MB 351 Exam 1
The system of nomenclature for organisms are scientific names that are
"latinized"
Electron wavelength
0.005 nm
Light resolution
0.2 micrometers
The limit of resolution for light microscope is
0.2 micrometers
The smallest object the human eye can see is about
0.2 mm or half a grain of salt
Electron resolution
0.2 nm
What is the average bacillus size?
0.5-1 micrometer wide by 1-4 micrometers long
An average coccus is about
0.5-1 micrometers in diameter
The simple microscope used by Aton Van Leeuwenhoek in the 1600s had how many lenses?
1
1 bacterium is about how long
1 micrometer
Spirals range in size from
1 micrometer to over 100 micrometers in length
marine microbes typically grow best between
1-4% NaCl
Typical glass has a reflective index of
1.5
Electron maximum magnification
100,000+
Light maximum magnification
1000 to 1500
How long did it take Europe's population to recover from the Black Death?
150 years
The 16S rRNA consists of
1542 bases and contains the substrate binding A-, P-, E- sites
The 30S subunit is composed of
16S rRNA and 21 ribosomal proteins
Light microscopes can visual a range of sizes from
200nm (.2 micrometer) to 10 mm
TEM gives you a
2D image with internal structures
Seawater contain how much NaCl
3%
Most natural environments have a pH between
3-9
1 m = ___ft
3.29
Scientists had evidence that cells first appeared on earth
3.8 to 3.9 billion years ago
Plasmids can contain 5-100 genes, but are usually less than
30
Robert Hooke's lenses achieved what fold power?
30-fold power
Prokaryotic ribosomes consists to two subunits denoted
30S (small subunit) and 50S (large subunit)
What is the 50S subunit made of
31 proteins, and 2 rRNA molecules, the 5S and 23S
The Black Death reduced the World Population from and estimated 450 million to
350 to 275 million
SEM gives you a
3d image with no internal structures
Eukaryotic ribosomes have two unequal subunits
40S (small subunit) and 60S (large subunit)
Light wavelength
530 nm
Estimates of total microbial cell numbers on earth are on the order of
5X10^30 cells
When the two subunits are joined together, the complete ribosome is the
70S, referring to the sedimentation coefficient in Svedberg units.
Eukaryotic ribosomes are also known as
80S ribosomes because they sediment faster than the prokaryotic 70S ribosomes
Mordant
A chemical which is added to the solution to intensify the stain. This may help to increase the affinity of the stain for the specimen
Overheating the organism in heat fixing causes what?
A distortion of the sample.
Capsule
A gelatinous covering meant to determine an organism's virulence
What are NAG and NAM linked by
A glycosidic bond with B-1,4 linage.
Lysozyme
A natural form of protection from gram-positive pathogens
What happens during protein synthesis?
A ribosome moves along an mRNA molecule, reading the codon and adding the correct amino acid (from the corresponding aminoacyl tRNA) to the growing protein. When the stop codon is reached, translation verses, and the mRNA and protein are released.
When the flagella motor goes CCW what occurs
A run
Chicken/Fowl Cholera
A serious, highly contagious disease caused by the bacterium Pasteurella multocida in a range of avian species includingg chickens, turkeys, and water fowl
What are Koch's postulates?
A set of rules and experimental procedures for the assignment of a microbe as the cause of a disease
Monotrichous
A single flagellum at one pole
Where is Y. Pestis naturally found?
A small type of rodent of Central Asia called a marmot
Pili gliding movemetn
A smooth gliding movement of myxobaceteria. It provides a means for microbes to travel in environments with low eater content such as biofilms and soil
Culture media
A solid or liquid preparation use to grow, transport and store microorganism. It is an aqueous solution to which all the necessary nutrients have been added
Twitching motility
A special "Type IV" pilus extend by the addition of subunits of piling. This makes contact with a surface or another cell and then retracts as the piling subunits are disassembled. This is called the grappling hook model of twitching and results in short, jerky, intermittent movements
Model organism
A species that has been widely studied, usually because it is easy to maintain and breed in a laboratory setting and has particular experimental advantages
Condenser
A substage lens which focuses the light on the specimens. Most condensers move up and down to focus the light beam
Antigen
A substance that elects antibody formation
In the 1950s and 1960s, the U.S. and Soviet Biological weapons programs developed techniques to directly aerosolize plague particles
A technique that leads to pneumonic plague, an otherwise uncommon, highly lethal and potentially contagious form of plague.
Lophotrichous and polar
A tuft of flagella coming from one pole
Describe the petri dish design
A two dish design that allows for gas exchange but prevent microbial contamination
Compound microscope
A type of light microscope which contains 2 lenses
Colony
A visible mass of microbial cells arising from one cell or from a group of the same microbes
What did Pasteur and his team announce they had discovered in April 1881?
A way to weaken anthrax viruses and so could produce a vaccine against it
Pathogenesis
Ability to cause disease
Needham's experimental design
After heating nutrient broth, he let a flask cool and sit at a constant temperature open to the environment for several hours. later the flasks would be sealed.
Slant cultures
Agar Media is poured into test tubes and allowed to solidify in an angled position so that the media has a "slant" to it allowing for greater surface area and inoculation on this slanted surface.
Who discovered Penicillin
Alexander Fleming
What is the poisonous ingredients in shellfish poisoning?
Algae-like organisms known as dinoflagellates which build up in some types of seafood
Cell Theory
All living cells are composed of cells and come from preexisting cells
What likely caused the microbial growth in Needham's experiment?
Allowing the broth to cool in an open container for several hours. The microbes in the air contaminated it leading to the microbial growth he observed
Lipid A serves as what when it is released?
An endotoxin
Capsules glycocalyx appearance
An extensive, tightly bound accumulation of gelatinous material adhering to the cell wall
Who does not have cell walls
Animal and protozoans
The acid-fast stain
Another type of differential staining which binds strongly to bacteria that have a way lipid material called mycelia acid in their cells
Phase contrast
Another way to observe living specimens and permits more detailed examinations of internal structures
The overall negative charge of the outer membrane of gram-negative cells protects the cell from
Antibiotics and limits the permeability of many compounds damaging to the cell
"Histone-like" proteins in
Archaea (prokaryotes)
Pseudomurein cell walls if
Archaea (prokaryotes)
Impacts of microorganisms
As agents of disease, environmental damage, microbial ecosystems, food production, agriculture, energy, biotechnology and model for basic science
How must specimens be prepared in TEM
As an ultra thing section or slices because the beam of electrons must pass through the sample to illuminate it. This gives you incredible internal detail of a cell or strucutre
What was leading to the collapse of the wine industry in France?
At the time, the wind industry of France was facing collapse due to problems with fermentation process leading to production of acidic byproducts and thus a sour taste.
Core Polysaccharide
Attached to lipid A and provides structural stability
Hook
Attaches to the filament. Is slightly wider in size than the filament
Yeast is particularly rich in
B vitamins
BSL 2:
BSL-2 builds upon BSL-1. If you work in a lab that is designated a BSL-2, the microbes there pose moderate hazards to laboratorians and the environment. The microbes are typically indigenous and associated with diseases of varying severity. laboratory personnel have specific training in handling pathogenic agents and are directed by scientists with advanced training; access to the laboratory is limited when work is being conducted; extreme precautions are taken with contaminated sharp items; and certain procedures in which infectious aerosols or splashes may be created are conducted in biological safety cabinets or other physical containment equipment.
Prokaryotes can be what shapes
Bacillus (rod), coccus (sphere)
Peptidoglycan (murein) cell walls if
Bacteria (prokaryotes)
There are no histones in
Bacteria (prokaryotes)
Examples of prokaryotes
Bacteria and Archaea
Anaerobe
Bacteria that doesn't utilize ozygen
All living organisms are classified into three domains of life
Bacteria, Archaea and Eukarya
What are the different types of microbes?
Bacteria, archaea, fungi, protozo, microscopic algae and viruses
Why are specimen visualized in brightfieqld microscopy?
Because of the differences in contrast (density) between the specimens and surroundings
Sterols
Believed to help protect mycoplasmas from lysis
The ability for glycocalyx to adhere to surfaces aids in what?
Biofilm formation and the ability to cause disease
What did Spallanzani's experiment show?
Biogenesis
What theory did Pasteur's experiment support?
Biogenesis
What theory does Redi's experiment support?
Biogenesis
What are some common features between prokaryotes and eukaryotes
Both have DNA as their genetic material, Both are covered by a cell (plasma) membrane, both contain RNA, Botha re made from the same basic chemicals (carbohydrates, proteins, nucleic acid, minerals, fats and vitamins, Both have ribosome, both regulate the flow of nutrients and wastes that enter and leave them, both have similar metabolism like photosynthesis and reproduction, both require a supply of energy and both are highly regulated by elaborate sensing systems ("chemical noses") that make them aware of the reactions within them and the environment around them
How did Pasteur's idea gain creditability?
By discovering that spoiled organisms could be inactivated in wine by applying heat at temperatures below its boiling point.
How does penicillin kill bacteria?
By interfering with the ability to synthesize the cell wall
How did Pasteur show the air was full of microorganisms?
By passing air through gun cotton filters. The filter trapped tiny parities floating in the air. By dissolving the cotton with a mixture of ether and alcohol, the particles were released and then settled to the bottom of the liquid. Inspection of this material revealed numerous microbes that resembled the typed of bacteria often found in putrefying media.
How was the incidence of Small pos decreased in countries of Asia and Africa?
By the practice of deliberately inoculating children with material from smallpox pustules
Both photoautotrophs and chemoautotrophs carry of the autotrophic process of
CO2 fixation
All cells consist mainly of
Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous and Sulfur
Chemical requirements for growth
Carbon, hydrogen, nitrogen, sulfur, phosphorous, micronutrients such as trace elements and growth factors, molecular oxygen (aerobes or anaerobes), various organic growth factors and water
Flagella special stain
Carnolfuschin
Rabies
Caused human victims to die a painful death and the disease appeared to be getting more and more common in France
Endotoxin
Causes an immune response in the host
Koch's third postulate
Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal
Iron is the chief trace elements and it play a key role in
Cellular respiration by seeing as the redox center or function as cofactors in enzymes involved in electron transport reactions
Streptobacillus
Chain of rods
Streptococcus
Chain of spheres
What are the two broad classes of culture media?
Chemically defined and complex
In order to overcome these limitations of a batch culture, what might be set up
Chemostats
What is the increasing order of susceptibility of avian species with Chicken Cholera?
Chicken, turkey, water fowl
What are the three most common shapes of bacteria?
Coccus, bacillus and spiral
Capsules special stain
Colloids (india ink)
Biofilm
Community of microorganisms living within a shared mass of secreted slime.
Complex media
Composed of a mixture of proteins and extracts in which the exact chemical composition is poorly defined, often made of natural source components - red blood cells, yeast extract, peptone, Casein, etc. It is used as a non-specific medium for growing many organisms
Body tube
Contains mirrors and prisms which direct the image to the ocular lens
Focusing knobs
Control the up/down movement of the stage
Spiral
Corkscrew or curved
What are the two types of glycocalyx
Cpasules and slime layer
Staphylococcus
Custer of spheres
What is analyzed to reveal the ancient divergence of the 3 domains of living organisms?
DNA sequences (specifically rRNA gene)
Soil microbes
Decompose organic waste and incorporate N2 gas into organic compounds: recycling all thees chemical elements between soil, water and air
Virulence
Degree to which a pathogen can cause disease
Beef extract (meat)
Derived from infusion of beef and provides an undefined source of nutrients. A Mixture of peptides, amino acids, nucleotidesm organic acids, minerals and some vitamins.
Tactic (taxis response behavior
Directed cell movements in response to a stimulus
Dominant Concepts during the 17th and 18th Century Microbiology
Disease are caused by "poisonous" air (miasmas), Disease are transmitted by touch (contagions), Creatures like maggot, flies, toads and snacks, microbes are formed directly from decaying matter
What did Varro believe in 120 BC?
Diseases were caused by small animal, too small to be seen and are carried in the air
Eukaryotes
Distinguished by their membrane bound nucleus, their DNA is consistently associated with chromosomal proteins and have a number of membrane enclosed organelles
Electron type of lens
Electromagnet
The MS and C rings
Embedded in the cytoplasmic membraen
What are the two important functions of glycocalyx?
Enables certain bacteria to resist phagocytic engulfment by white blood cells in the body or protozoans in soil and water. It also enables some bacteria to adhere to environmental surfaces which will lead to colonization of that surface
What is typically more difficult for phagocytic cells of the immune system to recognize and destroy?
Encapsulated pathogenic bacteria
Exoenzymes
Enzymes produces within the cell, then released outside the cell to begin the process of extracellular digestion
Pasteur Institute
Established by the French government as a major biomedical research center focused on antiserum and vaccine research
Divide by mitosis
Eukaryotes
Has histones
Eukaryotes
Has organelles
Eukaryotes
Sterols and carbohydrates that serve as receptors present in plasma membrane
Eukaryotes
True uncles, with nuclear membrane/envelope, nuceoli
Eukaryotes
What cells are generally larger, prokaryotes or eukaryotes?
Eukaryotes
What has paired chromosomes, in nuclear membrane?
Eukaryotes
Caseinase
Exoenzyme that hydrolyzes the milk protein casein
Since most cells are clear, what is used to bring up the contrast?
False coloring
Pseudopods
False feet
Who suggested the use of agar?
Fannie Wilshemius who was the wife of one of Koch's assistants
What did Fannie's agar provide?
Fannie suggested the use of agar as a solidifying agent, providing a level inert surface material for microbes to grow on, other nutrients (salts, sugars, proteins) could be included to satisfy the microbes nutritional needs
What are non polar tails made of
Fatty acids that are hydrophobic and insoluble in water
Examples of trace elements
Fe, Cu, Mo, Zn, B Co, Mn
What are the three parts of the flagellum
Filament, hook, basal body
What was Leeuwenhoek able to first view what with the simple microscope?
First single-celled organisms (animalcules)
There are a few advantages to the growth pattern of biofilms:
First, bacteria are protected from the inhibitory effects of antimicrobial compounds, biocides, chemical stresses (such as pH and oxygen), and physical stresses (like pressure, heat, and freezing). Second, the polymeric matrix increases the binding of water and leads to a decreased chance of dehydration of the bacterial cells—a stress that planktonic cells are subject to. And third, close proximity of the microorganisms in biofilms allows nutrients, metabolites, and genetic material to be readily exchanged.
Amphitrichous
Flagella on both poles of cell
What did Francesco Reid suspect?
Flies landing on the meat laid eggs that eventually grew into maggots
Where is algae most abundant?
Fresh and salt water, and in soil
Flies proteins
Function as the motor swtich
What does Gram staining look at
Fundamental differences in the cell wall of bacteria
Examples of eukaryotes
Fungi, protozoa and algae
Small scale cultivation on plates is done in
GasPak jars
Ways to grow bacteria
Generally you start off with either a solid or liquid culture, then the size of the culture you want, next figure out the nutritional requirements and make the media. Then you grow it in the right environment: in a incubator for solid (plate cultures) and standing liquid culture (bottle/flask).
Robert Koch provided definitive proof of what
Germ Theory of Disease
Scanning electron microscope (SEM)
Gives highly magnified, 3-d images of the specimen
Light type of lens
Glass
Limited LPS
Gram-positive
Thick peptidoglycan
Gram-positive
Tetrad
Group of four spheres
Phase contrast microscopes
Have a phase plate which filters out the original image components. The resultant image is the samples effect on light
How did Jenner confirm his cowpox theory?
He deliberately infected patients with matter from cowpox lesions. In May 1796, Jenner found a young dairyman, Sarah Nelms, who had fresh cowpox lesions on her had and arms. On May 14, 1976, using matter from Nelms' lesions, he inoculated an 8-year-old boy, James Phipps. Subsequently, he felt cold and had lost his appetitive, but on the next day hw was much better. In July 1796, he inoculated the boy again, this time with matter from fresh small pox lesions. No disease was developed, and Jenner concluded that protection was complete.
Lazzaro Spallanzani's experimental design
He repeated the experiments of Needham, but removed air from the flask, suspecting that the air was providing a source of contamination. Nutrient broth was placed in flask, heated, air removed, then sealed. No growth was observed
Redi experimental design
He used three pieces of meat. Once piece of meat was left in the open jar, resulting in maggots and flies. One piece of meat was left in a sealed jar, no maggots or flies could be observed as the meat decomposed. In the final test, a third piece of meat was overlaid with cheesecloth which allows air to go in, but not access for flies. Flies and maggots were observed on the surface of the cheesecloth but not inside the jar where meat was.
Spirochetes
Helical and flexible spirals. They have axial filaments, which resemble flagella but are contained within a flexible external sheath
Spirillum
Helical shape like a corkscrew, and are rigid, spirilla move using flagella
Electron medium of travel
High vacuum
Pasteur's experimental design
His experiment consisted of filling several short necked flasks with nutrient broth and then boiled the contents. Some were left open and allowed t cool, in a few days, these flanked were contaminated with microbes. The other flasks, sealed after boiling were free of microbes.
Robert Koch was an important microbiologist because
His pioneering work in the isolation and characterization of bacterial diseases helped to identify the causes of many of the maladies plaguing humanity
What did Needham's experiment support?
His results supported spontaneous generation.
Nosepiece
Holds the objective lenses, rotates
Penicillian was called a "miracle drug" because it doesn't harm human cells. Why doesn't it?
Human cells don't contain a cell wall
Why does Azithromycin not affect humans?
Humans do not have a 50S ribosomal subunit
How did this Y. Pestis get to Europe?
Hunters trapped Marmots for their fur and transported Tham along the Silk Road. Fleas that lived on them became the vector. The Black Death was believed to have started in China, travelled along the Silk Road and Reached the Crimea by 1346. From there, the fleas came in contact with black rates which were regular passengers on merchant ships, and it spread throughout the Mediterranean and Europe
What did Needham theorize?
If he took a nutrient broth and heat it, all living things in it would die and then he could observe if microbes were spontaneously going to arise after all for hem have been killed by the heat, or would none of them be able to come back.
What did Pasteur conclude from the gun cotton filters?
If these bacteria were present in the air then they would likely land on and contaminate any material exposed to it
BSL1:
If you work in a lab that is designated a BSL-1, the microbes there are not known to consistently cause disease in healthy adults and present minimal potential hazard to laboratorians and the environment. Work can be done on an open lab bench, requires a sink. Requires personal protective equipment (PPE) such as lab coats, gloves, eye protection.
Describe Pasteur's work with Joseph Meister
In 1885, a young boy, Joseph Meister, had been bitten by a rabid dog, and was brought to Pasteur. The boy almost certainly would have died an agonizing death if nothing was done so Pasteur took the risk on using his untested vaccine. The boy survived and Pasteur knew that he found a vaccine for rabies. Three months later, when he examined Meister again, Pasteur reported that the boy was in good health.
Cell envelope
In a prokaryotic cell, the portion composed of the plasma membrane, the cell wall, and the glycocalyx.
Conjugation
In bacteria, the direct transfer of DNA between two cells that are temporarily joined.
Describe how to properly stain using simple staining
In order to fix the cells to the slide before staining, use air drying and heat fixing. The organisms are heat fixed by passing an air-dried smear of the organism thought he flame as a gas burner or a slide warmer. The heat coagulates the organism's proteins causing the bacteria to stick to the slide. When you heat fix the slide, you want to apply enough heat to precipitate the proteins to allow the cells to stick to the slide y not to drastically change the shape of the cell. Once you fix the cells, you can now flood the slide with your stain, rinse well, and pat dry with paper.
Why do microorganisms move?
In response to a stimulus which could be food, nutrients (carbon or nitrogen), to flee a predator or catching prey
Where does H. pylori live?
In the interface between the surface of gastric epithelial cells (lining of the stomach) where it often clusters are the junction of epithelial cells
Where do most microbes obtain almost all of their nutrients from?
In the solution from the surrounding aqueous environment
Describe Pasteur's Chicken Cholera Vaccine experiment
In the summer of 1880, Pasteur found a vaccine by chance. Charles Chamberland had inoculated some chicken with chicken cholera germs from an old culture that had been around for some time. The chickens did not die. Pasteur asked Chamberland to repeat wheat he had done with a fresh culture of chicken cholera germs. Pasteur reasons that a new culture would provide more potent germs. Two groups of chickens were inoculated; one that had been given old culture and one that had not. This chickens that had been given the old culture survived, those that had not died. The chickens that had been inoculated with the old culture had become immune to chicken cholera
How does Azithromycin work?
It binds to the 50S subunit of the bacterial ribosome and thus inhibits translation of mRNA. Nucleic acid synthesis is not affected. It sits in the tunnel where it would occlude the nascent polypeptide chain from transiting through the subunit.
What was the aftermath of the Plague?
It created a series of religious, social and economic upheavals which had profound effects on the course of European history. It marked the end of the middle ages and the advent of the modern world. It created a society where there was much less competition ofr food, shelter, work, even at the lower levels of the social scale. People were able to prosper like never before.
Why was the spontaneous generation idea attractive
It meshed nicely with the prevailing religious vies of how God created the universe. There was a strong bias to legitimize the idea because the vital force was considered a strong proof of God's presence in the world
Growing microbes aerobically
It's pretty straightforward-you make the culture media with the required chemical elements, use agar if you want a solid medium or skip it for a broth/liquid medium. Sterilize the medium. Inoculate the medium, put it into the incubator or shaker and wait till it grows.
Beef extract function
Its function is to complement the nutritive properties of peptone by contributing minerals, phosphates, energy sources, and essential factors missing from peptone.
What was developed from the Germ Theory of Disease?
Koch's postulates
Mycoplasmas
Lacks cell wall and sterols are found in plasma membrane
Who discovered and observed the first bacteria, sperm cell, blood cells and microscopic nematodes and rotifers and much more?
Leeuwenhoek
Leeuwenhoek's microscope used what type of microscopy?
Light
LPS is composed of what
Lipid A, Core polysaccharide and Variable O-polysaccharide
What the 2 classes of teichoic acids?
Lipoteichoic acids and wall teichoic acid
Planktonic
Live within the water column of lakes and oceans
P ring
Located in the peptidoglycan
Who finally resolved the spontaneous generation vs. biogenesis debate?
Lous Pasteur
Examples of attenuated vaccines used in humans
MMR, Polio, Influenza, BCG for TB, Typhoid , Typhus
Endospores special stain
Malachite green
Microbes are an integral part of what ecosystem?
Marine and freshwater where they are producers in the ecosystem by photosynthesis and form the basis of the food chain
Who developed the TEM?
Max Knoll and Ernest Ruska in Germany in 1931
What did Redi conclude?
Meat could not be transformed into flies, only flies can make more flies, and proposed that the theory of Spontaneous generation could not be supported and was incorrect
What are the three main groups of archaea?
Methanogens, extreme halophiles and hyperthermophiles
Plate cultures
Microbes grow the surface of an agar plate
What did Pasteur conclude from his initial experiment?
Microbes in the air were the agents responsible for contaminating non-living matter
What did Needham claim?
Microbes spontaneously developed from his fluids.
The plasma membrane is also the site of energy conservation
Microbial energy generating processes involve the generation of a proton motive form (PMF) where proteins (H+) are selectively moved across the membrane
What is the most typical fungi?
Molds
How did wine producers believe wine was produced?
Most wine producers thought wine was completely abiotic chemical process, where you tossed some grapes together, waited a bit and then the sugars in the grapes were converted to alcohol thought a simple chemical process.
Aerotaxis
Move in response to oxygen concentration
Stage
Moveable platform on which slides are mounted for viewing;
Chemotaxis
Movement in response to chemicals. Process by which can organism migrate toward nutrient sand favorable environments and away from toxins and unfavorable environments.
Example of large multicellular fungi
Mushroom
The peptidoglycan polymer is made of what two sugars?
N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)
What did Spallanzani conclude?
Needham was wrong about spontaneous generation
Can large molecules such as proteins pass through the plasma membrane?
No
What are the exceptions to Koch's Postulates
Not always possible to obtain a disease causing microbe in pure culture (not culturable, biofilms), If humans are sole host, can't ethically test the postulates (HIV), Animal models are not always available, some microbes can be isolated from both healthy and sick individuals (cholera), Some viruses do not cause illness in all infected individuals (polio)
What is the core of a virus particle made of?
Nucleic acids which is surrounded by a protein coat
What do microorganisms need in order to grow and reproduce?
Nutrients, a source of energy and certain environmental conditions
Total magnification =
Objective lens X Ocular lens
Fimbriae location
Occur at the poles or can be even distributed over the entire surface of the cell
What did Hook use to provide light to his microscope?
Oil lamp
Genome
One complete copy of the genetic information in an organism
What were the two lenses in Robert Hooke's microscope
One lens was the eye piece while the other at the bottom was the objective lens
Vector
Organism that transmits the disease
Where is the cell well located in prokaryotes
Outside the cell membrane and provides these cells with structural support and protection and also acts a a filtering mechanism
Yeast
Oval shaped microbes that are larger than bacteria
Scanning Electron Microscope (SEM)
Overcomes the sectioning/slicing problem associated with the TEM and produces a 3D-image surface of the specimen. It involves "scanning" the beam of electrons across the sample
The most well known types of shellfish poisoning?
Paralytic shellfish poisoning, neurotoxic shellfish poisoning and amnestic shellfish poisoning
Describe Pasteur's rabies vaccine experiment
Pasteur injected "clean" animals with the rabies virus found in spinal cord that was fourteen days old. At this age, the virus was relatively weak and unlikely to threaten the life of the animals. He then used spinal cords that were thirteen days old, twelve days old etc on the animals until thy were injected with the most virulent virus found in infected spinal cords that was fresh. All survived this.
Pasteur's second experimental design
Pasteur next placed broth in open-ended long necked flasks and bent the necks into S-shaped curves called Swan flask. The broth in thee flanked were boiled and cooled. The broth in the flasks showed no sign of microbial life, even after months.
Germ Theory of Disease
Pasteur suggestion that microbes cause diesase
What is the name of the heating process used by Pasteur?
Pasteurization
The Black Death/Plague/Bubonic plague
Peaked in Europe between 1348 and 1350 and killed 30-60% of Europe
What is the 50S subunit involved in?
Peptide bond formation through peptide ttanderase activity. In addition, GTP binding proteins can interact with the subunit to aid in translation processes such as initiation, elongation and termination
Why is it advantageous for cells to be able to store phosphate as polyphosphate for future use?
Phosphate is often a limiting nutrient
Algae
Photosynthetic with a wide range of shapes and sizes
Typically no organelles
Porkaryotes
The dyes are usually what charge?
Positively charged or cationic
Chromosomal DNA arrangement usually a single circular chromosome, some have linear chromosomes, lack histones except for Archaea with histone-like proteins, plasmids
Prokaryotes
Divides using binary fission
Prokaryotes
No meiosis; transfer of DNA fragments only
Prokaryotes
What typically has one circular chromosome, not in a membrane?
Prokaryotes
What are the two groups that all living cells can be classified into based on their structural and functional characteristics?
Prokaryotes and Eukaryotes
How does the "proton turbine" work
Protons, flwoing through the MOT proteins may exert forces on charges present on the C and MS rings, thereby spinning the rotor and the attached filament. It can rotate at around 20,000 rpm with an energy consumption of only around 10-16 W
What do protozoa use to move?
Pseudopods, flagella or cilia
four broad classes of microbes in relation to their growth temperature optima:
Psychrophiles, mesophiles, thermophiles, hyperthermophiles
Gram-positive
Purple-blue staining
Gram-negative
Reddish-pink staining
Macronutrients
Required in large amounts by the cell
Immunity
Resistance to disease
What is the limiting factor in our ability to see small objects?
Resolution
Larger ribosomes (80s)
Ribosomes
Who was the first to build elaborate compound microscopes?
Robert Hooke
What is the shape, diameter and length of E. coli cells?
Rod shaped; 0.8 micrometers; 1-2 micrometers long
Bacillus
Rod-shaped
If you are only interested in the external features of an organism, what should you use?
SEM
What is smaller SEM or TEM?
SEM
What are the three types of stains:
Simple, differential and special
Another time when you will need enrichment cultures
Since microbes may be present in small numbers can be missed, especially if other microbes are present in much larger numbers, like for soil or fecal samples. The medium for an enrichment culture provides nutrients and environmental conditions that favor the growth of a particular microbe but not others.
Electron transparency
Sliced thin enough for electrons to pass through
During much of human history, infectious diseases dominated, one of the deadliest scourges to human kind was
Smallpox
How are polyphosphate granules used
Some and be degrade and used as source of phosphate for nucleic acids and phospholipid biosynthesis and in some organisms can be used to directly make ATP
extreme halophile
Some halophiles are capable of growth in very salty environments, typically 15-30% for optimum growth, and they cannot grow at all if the concentration is below this
Differential stains
Stains one kind of cell nut not another, helping to separate them into groups by utilizing different properties of the cell in order to distinguish them
Gram-negative bacteria
Stains red/pink and tend to be more resistant to antibiotics, but some types such as chloramphenicol and streptomycin might work.
Bacteria can also be what shape?
Star shape or square
Stells
Star shaped
The Golden Ages of Microbiology
Started roughly in the mid-1850s to the early 1910s. During this period, rapid advance lead to the establishment of Microbiology as a science
What do the teichoic acids provide?
Structural support, stabilizing the cell wall and making it stronger. It may also help in maintaining a negative charge of the cell wall and in ion transport
Most bacterial species are motile and move by
Swimming through liquid environments or by moving across surfaces
Maximum =
Temperature above which no growth occurs
Optimum =
Temperature at which the bacterium grows most rapidly
Minimum =
Temperature below which no growth occurs
Physical requirements for growth
Temperature, pH and Osmotic pressure
Fimbriae function
Tendency to adhere to each other and to surface, as a result, they are involved in forming biofilms. They can also help bacteria to adhere to epithelial surface in the body which helps the pathogen colonize the host and establish infection
neutrophils
Terms used to describe organisms that grow best at a neutral range (pH >5.5 and <8). The approximate pH for optimal growth is 7
What happens at the origin of bacterial chromosomes?
The DNA double helix is melted open by binding proteins, and then DNA polymerase synthesizes new strands in both directions which is known as theta replication
Koch's success depended on the technical achievements of what?
The Petri dish, agar and culture media
Resolution
The ability to distinguish two adjacent objects as separate and distinct
What did proponents of spontaneous generation discount about Spallanzani's experiment?
The air was required for the vital force to work
What did Pasteur conclude?
The chicken's bodies had used the weaker strain of germ to form a defense against the more powerful germs in the fresher culture. he found that the bacterium that causes chicken cholera lost its ability to cause disease.
The darker areas of an image produced by TEM represents
The dense areas of the object
What did Needham notice about his broth?
The development of a thick turbid solution of microorganisms (and thus microbial growth) in the flask
Iris Diaphragm
The diaphragm is located just below the stage and controls the amount of light which passes to the specimens and can drastically affect the focus of the image
Contrast
The difference in visual properties that makes an object distinguishable from other objects and the background. You will get a better image
Carboxysomes are inclusions that contain
The enzyme Ribulose 1,5 dispute carboxylase for carbon dioxide fixation
Chemically defined media
The exact composition of pure chemicals used to formulate the media is known
Yeast extract
The extract of yeast cells provides vitamins and other organic growth factors, they also supplement the organic Nitrogen and carbon compounds.
What is the first name?
The genus and is always capitalized and italicized
Spontaneous generation
The hypothesis that living organisms arise spontaneously from nonliving matter. It requires a "vital force," (present in air) to form life
Biogenesis
The hypothesis that the living organisms arise from preexisting life
This domain classification replaces the last highest classification of all living things
The kingdom
Lipid A
The lipid portion of LPS which acts as an anchor for the molecules into the cell membrane
Substances that dissolve easily in lipids enter and exit more easily than others because
The membrane consists of mostly phospholipids
Batch cultures
The more common is the batch culture where microbes are cultured in an enclosed vessel (tube, flask) with a broth medium that supplies its nutritional requirements. Microbes are inoculated into this medium and placed in an appropriate environmental condition. Microbes will adjust and grow in this medium until nutrients run out, and/or toxic waste products are accumulated, and there are too many cells-running out of space (physical limitation), and growth ceases.
What did Richard Petri invent?
The petri dish
What did Pasteur's work with wine reveal?
The process of converting sugar to alcohol is actually performed by various yeast strains. He then showed that the wine was going bad because a contaminating bacterial microbe was generating lactic acids instead of alcohol from sugar.
Magnetotaxis
The process of migrating along Earth's magnetic field lines
Why did Hooke call them cells?
The shape of the hollow cell walls in a slice of Cork reminded home of the shape of monks' cells in a monastery
What is the second name?
The specific epithet (species name) which is not capitalized and is italicized
Phylogenetic
The study of evolutionary relationships based on the ribosomal RNA (or other gene or protein)
What is microbiology?
The study of microbes
Koch's second postulate
The suspected pathogen must be grown in pure culture
Koch's fourth postulate
The suspected pathogen must be preisolated and shown to be the same as the original
The cell wall
The tough, usually flexible but sometime a fairly rising layer that surrounds some type of cells
What was discovered during the Golden Ages if Microbiology?
The true nature of infectious disease, the role of immunity in preventing and curing disease, people started studying the chemical role of microbes, the techniques for microscopy, culturing, vaccine development and improving surgical techniques
What did Pasteur's team know about the rabies virus?
The virus attacked the nervous system only after it had made its way to the brain.
Humans, animals and even insects depend of microbes in what locations?
Their intestines for digestion and synthesis of some vitamins
What did Edward Jenner notice about Milkmaids in the late 1700s.
There were protected from smallpox after they contracted cowpox, a related. ut much milder disease
What makes viruses a very different microbe?
They are not cellular, and are structurally very simple.
What makes archaea different from bacteria?
They did not have peptidoglycan in their cell walls
A few prokaryotes are pleomorphic meaning
They have the ability to alter their shape or size in response to environmental conditions
What common thread did Pasteur seem to find between wine and infectious diseases?
They might both involve infection by a microorganism
anaerobic chambers (also called a glove box)
This is usually a plastic chamber that contains an atmosphere of H2, CO2, and N2. Culture media are placed within the chamber by means of an airlock which can be evacuated and refilled with N2. From the airlock ,the media are placed within the main chamber where the work or cultivation is to be done. Any oxygen in the media is slowly removed by reaction with H2, forming water; there is also a palladium catalyst in here to aid the process. After being rendered oxygen free, the media are inoculated within the chamber (by means of the glove ports) and incubated (also within the chamber).
What is a disadvantage of using complex media
This nutritional composition is now precisely known
What is a major function of the cell well
To act as a pressure vessel, preventing over-expansion when water enters the cells
What did Robert Koch need to test the idea that microbes caused some diseases?
To isolate the causative agent
How did the team trace the rabies virus
To the brain and spinal cord of infected animals and by using dried spinal cord, they produced the vaccine for rabies
If aerobes are plain this an environment with air bubbles, where will they move
Towards the air bubbles
The consumption of undercooked pork could lead to
Trichinosis
Pili are involved in a special type of motility known as
Twitching motility
Protozoa
Unicellular microbes
Slime layer glycocalyx appearance
Unorganized and more loosely attached
Light microscopy
Use of any kind of microscope that uses visible light to observe specimens
Simple staining
Use one basic dye and its purpose is to highlight the entire organisms so that cellular shapes and basic structures are visible
For nutrition, what do most bacteria do?
Use organic compounds, some make their own food via photosynthesis and some get it from inorganic substances?
Special stains
Used to color and isolate specific parts of microbes, such as the endospores, flagella or to reveal the presence of capsules
Darkfield illumination
Uses a dark field condenser that contains an opaque disk, which is often used to examine unstained live specimen
Objective lenses
Usually 2-4 lenses with magnification of 4x, 10x, 40x, 100x oil immersion.
Light source
Usually a bright halogen bulb. The rheostat switch is used to regulate light intensity
Ocular lens or eyepiece
Usually at 10x magnification.
The practice of cowpox inoculations called
Vaccination
Who was the first to observe single celled microbes called "animalcules"
Van Leeuwenhoek
Who won the Nobel prize in chemistry in 2009 for showing what the ribosome looked like and how it functioned at the atomic level?
Venkatraman Ramakrishnan, Thomas A Steitz, Ada E. Yonath
What is important in the containment and control of infectious diseases?
Vigilance, research and public information
Transmission Electron Microscope (TEM)
Was the first type of electron microscope to be developed and is pattered exactly on the light microscope except that a focused beam of electron is used instead of light to "see through" the specimen.
When does it mean to be not culturable?
We don't know their nutritional requirements, some exist in communities attached to each other and a surface, like a biofilm, which are complicated ecosystems that may not be replicated in the lab. Many of these microbes can't live without other microbes.
Attenuated
When strains of bacteria or viruses lose its ability to cause serious disease in the host organism
Eukaryotes do what with their DNA
Wrap their DNA around proteins called histones to help package the DNA into smaller spaces
What pathogen is responsible for the Black Death?
Yersinia Pestis
A practical advantage to the chemostat is that
a cell population can be maintained in the exponential growth phase (where cells are rapidly dividing) for long periods, days or even weeks.
Agar
a complex polysaccharide polymer derived from marine algae. It isn't broken down by bacteria, unlike previously used gelatin or starch polymers. It provides an ideal solidifying medium platform.
MacConkey agar
a culture medium designed to grow Gram-negative bacteria and stain them for lactose fermentation. Selectivity of the medium is due to the presence of crystal violet and bile salts, which will both inhibit the growth of Gram-positive bacteria Differential action is based on lactose fermentation, which produces acid end products that causes the neutral red dye in this medium to turn red.
In prokaryotic cells, DNA is present in
a large double stranded molecule called the chromosome. It aggregates within the cell to Norma. mass called the nuceloid
The mycelia acid of acid-fast cells forms
a layer outside of a thin layer of peptidoglycan, which are help together by a polysaccharide
Biofilms usually consist of
a mixed bacterial population, but they may also consist of a single bacterial species
The major structures in the cytoplasm of prokaryotes are
a nucleoid (containing DNA), ribosomes, and reserve deposits called inclusion bodies
What is the polar head made of
a phosphate group and glycerol that is hydrophilic and soluble in water
Each phosophlipid bilayer contains
a polar head and non polar tails
A pure culture is defined as
a population containing only a single species or strain of bacteria. A culture is considered a pure culture if only one type of organism is present
What does the 5S rRNA molecule appear to act as
a seventh domain in the large ribosomal subunit in conferring stability to the entire 3D structure
To improve the resolving power,
a shorter wavelength is needed
Bacillus shaped
a single rod
The nucleoid of a bacterial cell usually contains
a single, long, continuous and frequently circularly arranged thread of double stranded DNA which is the cell's genetic material
In the streak plate method
a small amount of inoculum is picked up on a sterile inoculating loop, made of wire (easily sterilized by heating).The loop is drawn repeatedly across the surface of the plate, diluting microbes as it moves.
Lipopolysaccharide (LPS) is
a substance present in the outer membrane of gram-negative bacteria and penetrates into the surround environemtn
Glycocalyx
a sugary coat which is secreted by most Bactria. An outer viscous covering of fibers extending from the bacterium that is outside of the cell wall
The bacteria that become part of a biofilm engage in quorum sensing
a type of decision-making process in which behavior is coordinated through a "chemical vocabulary."
Gram staning is based on the
ability of the bacterial cell wall to retain a certain dye during solvent treatment
Nitrogen is
about 13% by dry weight of the cell and a key element in proteins, nucleic acids and other call parts
Light medium of travel
air
Acid-fast staining is used by microbiologist to identify
all bacteria in the genus Mycobacterium. This stain is also used to identify some pathogenic stains from the genus Nocardia
The optimum temperature reflects a state in which
all or most cellular components are functioning at their maximum rate and is usually closer to the temperature maximum than to the minimum.
What is included in the bacteria domain?
all pathogenic prokaryotes, many non-pathogenic prokaryotes found in soil and water and photoautotrophic prokaryotes
What are the three main types of growth factors
amino acids for proteins, purines/pyrimidines for nucleic acids and vitamins (mainly B-type vitamins)
Amylase
an exoenzyme the hydrolyzes stash into mono and disaccharide subunits
In gram-negative bacteria the peptidoglycan is surrounded by
an outer membrane on one side and by another inner cell/plasma membrane facing the inside of the cell.
Larger cultivation and processes are done in
anaerobic chambers (also called a glove box)
Basal. body
anchors the flagellum to the cell wall and plasma membrane
The rabies vaccine was the first vaccine tried on
animals
What is included in the eukarya domain?
animals, plants, protozoans, protists, and fungi
The gram-negative outer membrane which contains LPS, an endotoxin can block hydrophobic components such as
antibiotics, dyes and detergents protecting the sensitive inner membrane and cell wall
In between the origin and the terminus, the chromosome is condensed into
approximately 500 loops
If the pH is raised to 7, the cytoplasmic membrane of acidophiles
are destroyed and cells lyse.
Many microphiles are also capnophiles,
as they require an elevated concentration of carbon dioxide too.
What were the 3 processes philosophers believed living things arose from
asexual reproduction, sexual reproduction and from nonliving matter
Autotrophs
assimilate inorganic CO2 as a carbon source, reducing it (adding hydrogen atoms) to make complex cell constituents made of C, H and O.
Research over the last decade has shown that ____ also possess protein cytoskeleton components and remarkably, some of them are homologous to wukaryotic proteins such as tubular and actin
bacteria
Aerobes
bacteria that utilizes oxygen
Why was penicillin called a "miracle drug"
because it doesn't harm human cells
Why does acid-fast bacteria retain the red/pink cabolsuchsin stain
because it is more soluble in the waxy cell lipids in the acid alcohol mixture
Without a strong cell wall, the bacterium would
best from the osmotic pressure of the water flowing into the cells
The pathogenesis of gram-negative cells contributes to the ability to
bind to surfaces
Many microorganisms can satisfy their own requirements for growth factors through
biosynthetic processes (making their own) but some require one or more preformed from the environment and must then by supplied in the media culture in lab
The only difference between liquid (or broth) media and agar media is that
broths do not contain the agar component
Endospores can be dormant for thousands of years and may return to its vegetative state by a specialized process
called germination when conditions are improved for the cell.
Molecular oxygen (O2) is not toxic, but O2
can be converted to highly reactive toxic oxygen by-products
Facultative anaerobes (or facultative aerobes or just "facultative") are organisms that
can switch between aerobic and anaerobic types of metabolism. Under anaerobic conditions (no O2) they grow by fermentation or anaerobic respiration, but in the presence of O2 they switch to aerobic respiration.
halotolerant microbes
can tolerate some level of dissolved solutes, but grow best in the absence of added solute or very limiting quantities.
Molecules that carry a fixed charged
cannot cross the phospholipid bilayer
Aerotolerant anaerobes
cannot use oxygen for growth, but they tolerate it well. These bacteria use an exclusively anaerobic (fermentative) type of metabolism, whether or not O2 is present in their environment
In gram-positive cells, NAG and NAM serve as
carbohydrate "backbone" and cross linking them re tetra peptides (4 amino acids)
About half the dry weight of a typical cell is made of
carbon
Hydrogen and oxygen is usually attached to
carbon
The key macronutrients are
carbon and nitrogen
Under certain conditions, however, plasmids are at an advantage and can
carry gens for antibiotic resistance, tolerance to heavy toxic metals, produce toxins, synthesize specialized enzymes for the degradation of unique compounds and under in transferring genetic material between cells
Some of the membrane proteins
catalyze bioenergetic reactions, transport substances, detect environmental signs and secrete communication signals
The chromosome of prokaryotes is attached to the
cell membrane
The gram-negative cell envelope includes the
cell wall and the cell membrane compoents
Most cells appear colorless when viewed through a standard light microscope because
cells are mostly made of water
What is included in the archaea domain?
cells which do not have peptidoglycan in cell walls, live in extreme environments and carry out unusual metabolic processes
The plasma membrane have selective permeability indicating
certain molecules and ions pass through the membrane, while others are preventing. This allows the cell the to concentrate certain metabolites and excrete waste materials
Most vitamins functions as
coenzymes which are nonprotein components of enzymes
Vibrios
comma-shaped
The gas vesicles are
conical shaped structures made of protein; they are hollow yet rigid
Staining is what improves the
contrast between the specimens and the background of the slide
The polymer id further strengthen by
covalent bonds between cross-bridges and the degrees of cross-linking determines the degree of ridigity
Vacca
cow
Culturing
cultivating bacteria in a microbiology laboratory environment, and culture media contain the nutrients and other substances required to cultivate bacteria
A nutrient material prepared for the growth of microbes in a lab
culture media
Images produced with bright field illumination appear
dark and/or highly colored against a bright, often light gray or white background.
The 30S subunit has a crucial role in
decoding mRNA by providing the A, P and E binding sites and being responsible for monitoring base-pairing between he codon on mRNA and the anticodon on tRNA
Most microbes get nitrogen from
decomposing protein containing material and re-incorpoartion the amino acids into new proteins. Some use NH4+, some get nitrogen from nitrates in solution, while some photosynthetic cyanobacteria use N2 gas through nitrogen fixation
Peptones
derived from animal, milk, or meat digested by proteolytic digestion. In addition to containing small peptides, the resulting dried material includes fats, metals, salts, vitamins and many other biological compounds.
Obligate anaerobes (occasionally called aerophobes)
do not need or use O2 as a nutrient. In fact, O2 is a toxic substance, which either kills or inhibits their growth.
facultative halophiles
do not require high NaCl concentrations but are able to grow at salt concentrations up to 2%, a concentration that inhibits the growth of many other organisms
Both 40S and 60S subunits contain
dozens of ribosomal proteins arranged on a scaffold composed of ribosomal RNA, the 5S, 18S and 28S
Generally, you prepare reducing media for anaerobic cultures
during preparation of the culture media, it is boiled for several minutes to drive off most of the dissolved oxygen. A reducing agent, such as cysteine, is added to further lower the oxygen content, and oxygen free N2 is bubbled through the medium to keep it anaerobic. Then medium is then dispensed into tubes, again, flushed with N2, stoppered and then autoclaved.
Evidence indicates that all cells, organelles such as mitochondria and chloroplasts, and all major metabolic pathways evolved from
early prokaryotic cells
Sulfur is obtained from
either sulfur containing amino acid or from sulfate and sulfude
Electron radiation source
electron beam
Viruses can only be seen by what type of microscope?
electron microscope
The oxidation of sulfide is linked to the need for
electrons to drive either reactions of energy metabolism or carbon fixations
L ring
embedded in the outer membrane and LPS
Infectious diseases are not disappearing, but rather
emerging or reemerging
One example of an extreme survival strategy employed by certain Gram-positive bacteria (mostly in the Clostridium and Bacilllus genera) is the formation
endospores which is often initiated in response to nutrient deprivation
Many cells perform active transport whereby the cell uses
energy in the form of ATP in order to move substances across the plasma membrane
Sulfur granulates serve as
energy reserves
selective and differential characteristics are combined in a single medium
enhance the growth of certain species that can then be distinguished by other species due to variations in their effect on the medium or by the color of colonies they produce.
Chocolate agar
enriched with heat-treated blood (40- 45°C), which turns brown and gives the medium the color for which it is named.
Lipases
enzymes that break down lipids, which can be directly observed by changes in the appearance of a lipid structure
Often though, two or more cells are in a clump, they will grow to form only a single colony. So if a sample contains many cell clumps, a viable count (viable means one that successfully replicates to form a colony) of that sample may be
erroneously low
Microbes produces industrial chemicals such as
ethanol and acetone
Chromosomal (DNA) arragnement is multiple linear chromosomes; histones
eukaryotes
Cytoskeleton; cytoplasmic streaming in cytoplasm
eukaryotes
Meiosis
eukaryotes
Membrane associated organelles present
eukaryotes
All three Nobel laureates hade generated structures showing
exactly where different antibiotic attack bacterial ribosomes
Electron microscopes were developed to
examine structures too small to be resolved with a light microscope such as ribosomes, but can also give gene detail for large structures such as a red blood cell
O-polysaccharide
extend outward from the core polysaccharide and is made of sugar molecules. It functions and an antigen
Plasmids are
extra-chromosomal genetic elements that are not connected to the main bacterial chromosomes and replicate independent of the chromosomal DNA
Chemotaxis occurs in many species of bacteria when
extracellular signals are detected by transmembrane receptors and relayed to flagellar motors
Where are archaea usually found?
extreme environments, very hot, very cold, very salty, low/high pH
Obligate anaerobic prokaryotes may live by
fermentation, anaerobic respiration, bacterial photosynthesis, or the novel process of methanogenesis.
Without resolution, no matter how much the image is magnified, the amount is observable detail is
fixed
Peritrichous
flagella distributed all over the cell
In a prokaryotic cell, the term cytoplasm refers to the
fluid-like substance inside the cell membrane. It represent nearly 70% of the wet weight of the cell. It is about 80% water and contains primarily proteins (enzymes) carbohydrates, lipids, inorganic ions, ions, dissolved gases.
Chemostat in microbial ecology
for enrichment and isolation of bacteria for nature by selecting for a stable population under nutrient and dilution rate conditions chosen
Superoxide free radicals or superoxide anions, are
formed in small amounts during normal respiration of microbes that use oxygen as the final electron acceptor. These radicals are toxic to cellular components.
The proteins move to
function
MOT proteins
function as the flagellar motor
Water availability is not only dependent on how moist or dry an environment is, but also a
function of the concentration of solutes (salts, sugars, etc.) dissolved in the water that is present.
Many planktonic organisms can float because they contain
gas vesicle which cause buoyancy which allows the cells to position themselves in a water column in a particular location
"Immersion oil"has the same refractive index as
glass
Abundant LPS
gram-negative
Excel in host intestinal environments
gram-negative
High lipid content
gram-negative
Low susceptibility to penicillin
gram-negative
No techoic acids
gram-negative
Outer membrane
gram-negative
Periplasmic space present
gram-negative
Susceptible to mechanical stress
gram-negative
Thin peptidoglycan
gram-negative
low susceptibility to lysozymes
gram-negative
The o-polysaccharide if useful in distinguishing species of
gram-negative bacetai
Abundant techoic acids
gram-positive
Better in dry conditions
gram-positive
High susceptibility lysozymes
gram-positive
Low lipid content
gram-positive
Penicillin sensitive
gram-positive
Periplasmic space absent
gram-positive
resistant to mechanical stress
gram-positive
Acidophiles
grow at pH<5.5, there are different classes of acidophiles, some grow best at moderately acidic pH (pH5) and others at very low pH (pH 1). Some acidophiles are obligate (require) acidic conditions
Its been hypothesized that one function of magnetosomes may be to
guide these primarily aquatic cells downward toward the sediment where oxygen levels are lower
Unidirectional flagella
have to stop, reorient itself in order to change direction
In Gram-positive cells the peptidoglycan is
heavily cross-linked woven structures that encircles the cell in many layers. It is very thick with peptidoglycan accounting for 50% of weight of cell and 90% of the weight of the cell wall.
The organic compounds made by autotrophs can then be used by
heterotrophs
Acidophiles are not just acid tolerant but require
high concentrations of H+ for membrane stability.
Through their anaerobic metabolism, some magnetosomes will accumulate
high concentrations toxic metal from the water
Thermophiles
high temperature optima. Certain bacteria can live and grow at temperatures that exceed 50degC
Endosporescan survive environmental assaults that would normally kill the bacterium. These stresses include
high temperature, high UV irradiation, desiccation, chemical damage and enzymatic destruction.
Brilliant Green Agar
highly selective medium used to inhibit gram-positive bacteria and most gram- negative bacilli for the selective isolation of gram negative Salmonella species from feces and other clinical specimens.
Digestive exoenzymes break down large molecules into smaller ones via
hydrolysis
mixed culture
if populations of different organisms are present (as seen here in this top plate, note the different colony types)
Confocal microscopy
illuminated each plant in a specimens to produce three-dimensional images up to 100 micrometers deeps. It uses fluorescence as well
Mangetosomes
impart a magnetic dipole on a cell, allowing it to orient itself in a magnetic field
gas vesicles are
impermeable to water and solutes, but permeable to gases.
Gas vesicles occur almost exclusively
in prokaryotes from aquatic habitats
The hydroxyl radical is another intermediate form of oxygen and probably the most reactive. It is formed
in the cytoplasm by ionizing radiation.
What physiological reactions does LPS create?
induction of fever, changes in white blood cell count, leakage from blood vessels, tumor necrosis and lowered pressure leading to vascular collapse and eventually shock. It can be lethal at high enough concentrations.
Bacterial exoenzymes are produced in the largest amount on an
industrial basis, used as additives in laundry detergents
Bacteria that break away from a biofilm can cause
infections in patients using catheters
The difference in color shade in TEM images provides
information on the structure, texture, shape and size of the sample
What are some of the outcomes of antibiotics attacking bacterial ribosomes
inhabit the monitoring mechanism of the molecular ruler, under the formation of the connection between amino acids or block the tunnel through which the merging protein chain leaves the ribosome
Coarse focus
innermost
GasPak jars
inoculated plates or tubes are placed inside the jar, and anaerobic conditions are created by adding water to a gas generator envelope placed in the jar just before sealing. The envelope contains two chemical tablets: sodium borohydride and sodium bicarbonate. Water reacts with them producing hydrogen gas and CO2. The H2 combines with free oxygen in the chamber to produce water, removing all the free oxygen from the chamber. This reaction is catalyzed by palladium, which is attached to the underside of the lid of the jar. The CO2 replaces the removed oxygen, creating a completely anaerobic environment.
Trace elements are
inorganic
Phosphorous is usually supplied to a cell as
inorganic phosphate
Sulfure originates from
inorganic sources in nature (sulfate and sulfide)
Pili fucntion
involved in DNA transform. They often play an important role in connecting two cells for the exchange of genetic material, and in the attachment to host cells during infection
Among the substances actively transported are
ions, amino acids, and simple sugars
Blood agar
is considered to be differential but not selective, because it is an enriched medium that provides a rich nutrient environment for many types of bacteria, while a selective medium supports the growth of certain types of bacteria but inhibits other types.
In gram-negative bacteria, the peptidoglycan
is much thiner with only 15-20% of the cell wall being peptiodyglycan and it is only intermittently cross-linked with tetapeptide side cahins
Phosphorous
is need for synthesis of nucleic acids and phospholipids and is also found in high energy bonds of ATP. Can occur as organic or inorganic phosphates
Complex media are often referred to as "Rich" media, which means
it contains the nutrients required to support the growth of a wide variety of organisms, including some of the more fastidious ones.
Any type of staining going to
kill cells and distort its features to some degree
BSL-4
labs builds on the containment requirements of BSL-3 and is the highest level of biological safety. BSL-4 labs is required for work with dangerous and exotic agents that pose a high individual risk of life-threatening disease, aerosol transmission or unknown risk of transmission. The microbes in BSL4 labs cause infections that are frequently fatal and generally there are no vaccines or treatments for these infections. There are only a small number of such labs in the U.S (<10) and the world. Laboratory staff must have specific and thorough training in handling extremely hazardous infectious agents. Access to the laboratory is controlled by the laboratory supervisor. All handling of agents must be performed in a gas tight Class III Biosafety Cabinet or by personnel wearing a positive pressure protective suit. BSL-4 Laboratories have special engineering and design features to prevent microorganisms from being released into the environment. The lab is in a separate building or isolated restricted zone of the building, and has a dedicated supply and exhaust air, as well as vacuum lines and decontamination systems. Personnel mush change clothing before entering and shower upon exiting.
Phospholipids rotate and move
laterally
microbes produce products uses in manufacturing food additive and many important enzymes are used in your
laundry detergent and medicine such as insulin
In this complex biofilm network, the cells act
less as individual entities and more as a collective living system, often with channels to deliver water and nutrients to the cells at the inner portion of the biofilm
These enzymes are often able to convert these toxic oxygen radicals to something less damaging,
like water.
Wall teichoic acid
linked only to the peptiodglycan layer
The outer membrane of gram-negative bacteria is another lipid bilayer similar to the cytoplasmic membrane and contains
lipids, proteins and LPS
Most move by using a flagella which are
long filamentous appendages that propel bacteria
Filament
long outermost region that is made of flagellin proteins
Stab cultures are good for
long term storage of microbes and also for figuring out motility and oxygen requirements.
Slant cultures are also suitabitl for
longer term maintenance of bacteria
The bacterial DNA is packed into
loops back and forth which concentrates the DNA of the cell, but it is not separated by a nuclear membrane.
Loss of light leads to
loss of image detail
psychrophiles
low temperature optima These are cold loving microbes that prefer a range from just below 0degC to 11degC.
Glycosidic bonds are sensitive to
lysozyme
Differential media
make it easier to distinguish colonies of the desired organism from other colonies growing on the same plate. It is a media that supports growth of many different organisms, but differentiates between them. This type of media will allow identification of microbes based on their growth, color, and appearance on the medium
There are numerous antibacterial agents that target the bacterial cell wall because
mammals do not synthesize walls and therefore are not susceptible to the toxic effects of these agents
batch cultures
meaning they are closed systems, the microbe is growing in an enclosed vessel: you put a set amount of liquid culture media in a bottle/flask/test tube and inoculate it with your microbe, there is no new media supplied during the course of growth, once they use up all the nutrients, they generally stop growing.
thioglycollate is a
medium that may be used in two ways: to grow microorganisms under anaerobic conditions, or to test for the oxygen requirements of a bacterium.
Volutin
metachromatic granulates which act as a storage form of complexed inorganic polyphosphates
Halophiles
microbes that inhabit these marine environments almost always have a NaCl requirement
Biofilms on surfaces have a characteristic structure consisting of
microcolonies enclosed in a hydrated matrix of microbially produced : proteins, nucleic acids, and polysaccharides, often called a slime or hydrogel
mesophiles
midrange temperature optima. These are the moderate-temperature loving microbes, with a range form 9 to 48degC. Neither too hot nor too cold, typically between 25 and 40°C (77 and 104 °F).
We use special oil immersion lenses to
minimize refraction
Some diseases are polymicrobial meaning
more than one pathogen is the cause, so you won't be able to get a pure culture all the time to test
Contamination means that
more than one species is present in a culture that is supposed to be pure
Microorganisms sense and adapt to changes in their environment. When favored nutrients are exhausted, some bacteria may become
motile to seek out nutrients, or they may produce enzymes to exploit alternative resources
In broth, a species may display
motility and/or a characteristic pattern of association among individual cells, such as chains or clusters, that is not obvious in agar cultures
Some bacterial with color flagella will have reversible motors that allow them to
move forward when it turns CCW and backwards when it goes CW
If you are converting to larger numbers,
move the decimal to the left or divide
To convert to smaller units,
move the decimal to the right or multiply
Phototaxis
movement in response to light
Fungi can be
multicellular or unicellular
Prokaryotes often only have a singular enclosed circular chromosome. However, some have
multiple chromosomes or even linear chromosomes
These growth factors may be needed in varying concentrations, ranging from
none to mg quantities per liter
Singlet oxygen is
normal molecular O2 that has been boosted into a higher energy state and is extremely reactive.
Special techniques, commonly referred to as aseptic pure culture techniques, must be used to
obtain a single isolated strain for study
The compound light microscope uses what two lenses to magnify the specimen image
ocular and objective
Spiral shaped
one or more twists; they are never straight
Pure culture
one species of microbe in isolation
Thus, each colony on an agar plate represents
one viable organism (or CFU) present in the original liquid culture
Growth factors are
organic and required in small amounts only by certain organisms
Microbes/microorganisms are
organisms that are too small to be seen with the unaided eye
bacterial chromosomes are arranged with a
origin of replication at one end and a terminus at the other
Fine focus
outermost
Chemoautotrophs gain energy by
oxidizing inorganic substances such as iron or ammonia
Diplobacillus
paired rods
Diplococcus
paired spheres
Peroxide anions are produced as
part of Hydrogen peroxide (H2O2).
In Mosaic Law,
people understood that there were certain foods that were to be avoided, such as pork and seafood
The 60S subunit catalyzes
peptide bond formation
Gram-positive cell walls are mainly
peptidoglycan and threading between this is teichoic acids which consists primarily of an alcohol and phosphates
The space between the outer and inner membrane where peptidoglycan is found is known as
periplasm
Usually a redox indicator dye such as resazurin is present to signal oxic (oxygen-containing regions); the dye is
pink when oxidized and colorless when reduced and thus gives you a visual assessment of the degree of penetration of O2 into the medium.
Biofilm organisms are significantly more resistant to environmental stresses or microbially deleterious substances (such as antibiotics and biocides) than
planktonic (floating or free-living) cells
What is algae associated with?
plants
Cells walls are found in
plants, bacteria, fungi, algae and some archaea
In addition to bacterial chromosomes, bacteria often contain small, usually circular double strand DNA molecules called
plasmis
Mineral ions are necessary in most microbes, elements such as iron, potassium, and sodium because they
play an important role in enzymes and macromolecules
Some bacteria use special gas vesicles which contain
pockets of gases for buoyancy and move up and down the water column
Many microbes accumulate inorganic phosphate in the form of
polyphosphate also known as volutin
One way prokaryotes compress their DNA into smaller spaces is through supercoiling which causes
portions of DNA to double back and twist itself. These interactions are stabilized by proteins
Alkaliphiles
prefer pH of 8 or above.
Azithromycin
prevents bacteria from growing by interfering with their protein synthesis
endospores allow the cell to
produce a dormant and highly resistantcelltopreservethecell'sgeneticmaterialintimesofextremestress.
Cytoskeleton proteins that are homologs to eukaryotic proteins in cytoplasm
prokaryotes
Membrane associated organelles generally absent
prokaryotes
No carbohydrates and usually lacks sterols in plasma membrane
prokaryotes
No nuclear membrane or nucleoli
prokaryotes
Smaller ribosomes (70s)
prokaryotes
Ribosomes contain both
protein and RNA molecules
Proteases hydrolyze
proteins into amino acid subunits
The plasma membrane also serves as a protein anchors which allows
proteins to anchor together in different layers of the cell envelop providing structural support
Electron microscopes
provide approximately another 1000-fold maginification over light scopes
In prokaryotes, gas vesicles function to
provide buoyancy, which allows aerophilic bacteria to float into oxygenated surface waters .
Stab (deep) cultures:
puncturing suitable medium such as nutrient agar with an inoculating needle that goes deep into the agar, allows growth within the semi-solid media.
Koch was also able to isolate bacteria in a
pure culture
In the Fluid mosaic model, phospholipids and proteins are not static but move
quite freely
Haloarcula
rectangle shape
The acid-fast stains will retain the
red/pink carbolsuchsin stain
Majority of bacteria are heterotrophs meaning they
rely on other organisms to form the organic compounds (such as glucose) that they use as carbon sources
After melting, agar
remains liquid down to 50 degrees Celsius which makes it easy to dispense, pour into containers, tubes, or dishes.
High osmotic pressures have the effect of
removing necessary water from a cell.
Obligate aerobes
require O2 for growth; and can grow at full oxygen tensions (air is 21% Ox); these microbes use O2 as a final electron acceptor in aerobic respiration.
Micronutrients
required be the cell in small amounts
BSL-3
required for work involving indigenous or exotic agents, and they can cause serious or potentially lethal disease that are transmitted through the air (via aerosols). Respiratory transmission is the inhalation route of exposure. Laboratory personnel must receive specific training in handling pathogenic and potentially lethal agents, and must be supervised by scientists competent in handling infectious agents and associated procedures. Lab personnel are under medical surveillance and might receive immunizations for microbes they work with. All procedures involving the manipulation of infectious materials must be conducted within Biosafety Cabinets (BSCs). A BSL-3 laboratory has special engineering and design features that prevent the release of microorganisms to the environment. Facilities have hands free sink, exhaust air cannot be recirculated, entrance is through two sets of self closing and clocking doors.
A microaerophile
requires oxygen to survive, but requires environments containing lower levels of oxygen than are present in the atmosphere. Therefore they need oxygen levels that are <20% concentration(which is atmospheric oxygen concentration).
What are tumbles caused by
reversal of the flagella rotation
All prokaryotes and eukaryotes contain ___ which functions as the sites of protein synthesis
ribosomes
Due to the lack of sterols in the plasma membrane, prokaryotic membranes are less ___ than eukaryotic membranes
rigid
The basal body contain a small central rod inserted into a series of
rings
coccus
round, spherical
When bacterium moves in one direction for a length of time, the movement is called a
run or a swim
Combination of rRNAs and proteins typically have a ______ than their component parts due to condensations
sedimentation rate (S)
The most important function of the plasma membrane is to
serve as a selective barrier through which material enter and exit the cells
Magnetosomes have been found in
several aquatic organisms that grow at low oxygen concentrations
Prokaryotes
single celled organisms, whose genetic material is not enclosed in a special nuclear material
The NAM, NAG and amino acid side chain from a
single peptidoglycan unit that can link with other units via covalent bonds to form repeating pikymers
Coccus shape
single sphere
The LPS of gram-negative cells lead to
some antigenic variability
Polysaccharide cell wells in
some eukaryotes - not in animal cells
Heterotrophs get most of their carbon from the
source of their energy-organic materials such as proteins, carbohydrates, and lipids. This usually supplies their hydrogen and oxygen requirements
Lipteichoic acids
span the peptidoclcyan layer and is linked to the cell membrane
Bacteria are enclosed in what?
special cell walls made of carbohydrates and proteins called peptidoglycan
Endospores are
special resistant, dormant structure formed within a cell that protects the bacterium from adverse environmental conditions
Inclusion bodies are
specialized structures often present in prokaryotes which may function as energy reserves an for carbon reservoirs or have special functions for motility
We use broths primarily for
specific assays or (rarely) for bacteria that will not form colonies on a solid surface
The dyes we use a usually organic compounds which bind to
specific cellular materials
Larger, uncharged polar molecules such as amino acids cannot pass through the plasma membrane unless three is a
specific transporter protein
What are the shapes of nucleoids
spherical, elongated or dumbbell shaped
Endospore stability may come from
spore specific chemicals such as dipicolinic acid and proteins that protect the DNA.
For many microbes, O2 is an
ssential nutrient; others cannot grow in its presence and may even be killed by it.
The development of a biofilm in vitro involves the following 5 stages
stage 1: reversible attachment of bacterial cells to a surface, Stage 2: irreversible attachment mediated by the formation of exopolymeric (polysaccharides, etc) material, Stage 3: formation of microcolonies and the beginning of biofilm maturation, Stage 4: formation of a mature biofilm with a 3-dimensional structure containing cells packed in clusters with channels between the clusters that allow transport of water and nutrients and waste removal, and Stage 5: detachment and dispersion of cells from the biofilm and initiation of new biofilm formation
Gram-positive bacteria
stain purple/blue and tens to be sensitive to penicillin and cephalosporin antibiotics
One way to visualize these colorless cells is by
staining the specimen
Iodine binds to
starch
After solidifying, agar
stays solid up to nearly 100 degrees Celsius allowing incubation at warm temperatures
The isolation method most commonly used to get pure cultures is the
streak plate method/t-streak/quadrant streak/isolation streak
The 16S rRNA is important for
subunit association and translational accuracy
Many gram-negative prokaryotes can oxidize reduced
sulfur compounds
Elemental sulfure for the oxidation of sulfide may accumulate in the cell in
sulfure granules
the Peroxidation of lipids is a major consequence of exposure to these oxygen forms and the cell possesses various enzymes:
superoxide dismutase, catalase, peroxidase, as well as cellular antioxidants which are able to scavenge oxygen free radicals and repair peroxidized lipids.
Selective media are designed to
suppress/inhibit the growth of unwanted bacteria and encourage the growth of desired microbe
Fluorescence microscopy
takes advantages of fluorescence, the ability of substances to absorb short wavelength of light (UV) and gives off a light at a longer wavelength (visible). Cells may be stained with fluorescent eyes. It is used to visualize location or pattern of fluorescence in cells
The process of endospore formation within a vegetative cell (which is an actively growing cell)
takes several hours and is known as sporulation.
These biofilm communities consist of sessile organisms, meaning
that they grow attached to a surface
When did the Black Death finally leave Europe?
the 19th Century
Sulfur is needed in
the amino acid cystine and methionine and also in vitamins like thiamine and biotin
Nitrogen is used primarily fro
the amino group of amino acid proteins and DNA and RNA synthesis
Biosafety
the application of safety precautions that reduce a scientists' risk of exposure to a potentially infectious microbe and limit contamination of the work environment.
Refraction
the bending of light as it travels through substances with different densities
Many bacteria in biofilms are often resistant to antibiotics because
the biofilm offers a protective barrier
The development of a biofilm allows for the cells inside to become more resistant to
the body's natural antimicrobials as well as the antibiotics (antibiotic resistance) administered in a standard fashion.
The 16S rRNA makes up
the bulk of the 30S subunit
In non acid-fast bacteria lacking lipid components
the carbolsuchsin is removed and leaves cells colorless. A counterstain is applied than these cells will stain blue, distinguishing it from the acid-fast microbes.
When a microbe is in a solution whose concentration of solutes is higher than in the cell (the environment is hypertonic to the cell),
the cellular water passes out through the plasma membrane to the high solute concentration. This osmotic loss of water causes plasmolysis, or shrinkage of the cell's cytoplasm. This will inhibit cell growth
40S monitors
the complementarity between the tRNA anticodon and mRNA
When the flagella motor foes CE,
the flagella gly apartment and the cell tumbels
In a chemostat
the growth chamber is connected to a reservoir of sterile medium. Once growth is initiated, fresh medium is continuously supplied from the reservoir. The volume of fluid in the growth chamber is maintained at a constant. Fresh medium is allowed to enter into the growth chamber at a rate that limits the growth of the bacteria. The bacteria grow (cells are formed) at the same rate that bacterial cells (and spent medium) are removed by the overflow
Thus adding salts to a solution results in
the increase of osmotic pressure which can be used to preserve foods
Gram stain is widely used in medical microbiology to provide
the initial characterization and classification of bacteria.
chemostat relieves
the insufficiency of nutrients, the accumulation of toxic substances, and the accumulation of excess cells in the culture, which are the parameters that initiate the stationary phase (where cell growth is equal to cell death) of the growth cycle
Exoenzymes are classified on the basis of
the kind of molecules they hydrolyze
H. pylori
the main cause of chronic superficial gastritis and is associated with both gastric and duodenal ulcer.
The charge of the dye causes it to bind to
the negatively charged cell components such as the negatively charged backbone of DNA, cell proteins or membranes
The most important feature of the 23S rRNA is
the peptide transferase center, the site where peptide bonds are formed
The lighter areas of a image produced by TEM represents
the places where a greater number of electron were able to pass through
Osmotic pressure
the pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane (like the plasma membrane). It is also defined as the minimum pressure needed to nullify osmosis.
as temperatures rise,
the rate of enzymatic reactions increases and growth becomes faster. However, above a certain temperature, proteins or other cell parts may be denatured or irreversibly damaged.
Gram staining is an important step in
the screening of infectious bacteria for a patient, which could help a doctor prescribe the right course of treatment
Fixed position lenses
the stage moves up and down rather than the lens
The sulfur remains in granules as long as the source of the reduced sulfur from which is was derived from is still present. However, as the reduced sulfur source becomes limiting,
the sulfur granules is oxidized to sulfate and the granules will slowly disappear as the reaction proceeds
SEM is especially useful in studying
the surface structures of intact cells and viruses
Koch's first postulate
the suspected pathogen must be present in all cases of the disease and absent from healthy animals
The resolving power of a microscope is limited by
the wavelength of light
What causes the toxicity of superoxide free radicals
their great instability, which leads them to steal an electron from a neighboring molecule, and this repeats itself.
The Cardinal temperature
there is a minimum temp below which growth is not possible, and optimum temperature at which growth is most rapid, and a maximum temperature above which growth is not possible.
The extraordinary resistance properties of endospores make them of particular importance because
they are not readily killed by many antimicrobial treatments and could be a problem in food and medical industries.
Metals are important elements because
they are used as cofactors in enzymes to stabilize membranes and cell structures
Biofilms can also be a problem in industry:
they can be a problem in pipes and tubing where their accumulations impede circulation, such as in indwelling medical devices, including mechanical heart valves and catheters. Biofilms can do long term damage to water distribution facilities and other public utilities, causing fouling of equipment and contamination of products.
In tact gas vesicles can provide buoyancy because
they have an overall density much less than that of the aqueous medium in which the various organisms grow.
Complex media usually provide the full range of growth factors that may be required by an organism so
they may be more handily used to cultivate unknown bacteria or bacteria whose nutritional requirement are complex
Prokaryotes are monomorphic meaning
they stay the same shape
If anaerobes are placed in an environment with air bubbles, where will they move
they will disperse
Archaea have atypical cell walls because
they wither lack cell walls completely ot have unusual walls made of polysaccharides and proteins, but not peptidoglycan
The prokaryotic plasma membrane is a
thin structure lying inside the cell wall and encloses the cytoplasm of the cell and consists of a phospholipid bilayer with lipid-soluble proteins.
Gas vesicles in cyanobacteria (which are photosynthetic) allow
this species to float up toward the light; allowing them to migrate to the optimal light levels in water column.
Chemostat in microbial physiology
to mimic low substrate concentrations often found in nature and probe which microbes in mixed cultures of known composition can best survive nutrient limitations.
Thioglycollate in the medium serves as a reducing agent
to remove traces of O2 by reducing it to water.
LPS is medically important because when LPS is released from a dead bacterial cell it is
toxic to mammals and is therefore an endotoxin
Microbes require several metals for growth, typically in very small amounts and are referred to as
trace elements
The 23S molecule is involved in
translocation and peptide bond formation
Penicillin actually works by stopping the
transpeptide enzyme from building cross bridges, which ultimately weakens the cell well and leads to osmotic lysis of the cell
The various proteins found int eh cell envelope of gram-negative cells work to
transport
Rusnare interrupted by periodic, abrupt, random changes in direction called
tumbles
every microbe has a pH range
typically about 2- 3pH units, within which growth is possible. Also, each microbe shows a well defined pH optimum, where growth occurs best.
Most bacteria are
unicellular
The element Oxygen is a
universal component of cells and is always provided in large amounts by H2O.
Autotrophs are classified as Photoautotrophs which
use light for photosynthesis
Mannitol Salt agar (MSA)
used to isolate and differentiate Staphylococcus aureus, a common bacterium found in nasal passages. This microbe has a tolerance for high concentrations of sodium chloride, largely because their adaptation to salty habitats such as the human skin. It can also ferment the carbohydrate mannitol to form acid.
The vast majority of microbes are quite
useful
Can small molecules such as water, oxygen, carbon dioxide pass through the plasma membrane?
usually
Enrichment media:
usually a complex medium base to which additional nutrients such as serum or whole blood are added. These added nutrients better mimic conditions in the host and are required for successful lab culture of some human pathogens
Pili form
usually longer than fimbriae and only have 1-2 per cell.
Brightfield illumination is best suited for
utilization with fixed, stained specimens or other kinds of samples that naturally absorb significant amounts of visible light.
Molecular oxygen (O2) requirements
vary between different species of microbes
Given the exponential reproduction rate and the rate of spontaneous mutation
ven a pure bacterial culture will contain spontaneous mutant cells that will vary in their nucleotide sequences from the original cells. Thus the culture is not perfectly homogenous
Microbes produce fermented foods such as
vinegar, cheese, and bread
Light radiation source
visible light
A "colony" is a
visible mass of microbial cells arising form one cell or spore or from a group of the same microbes.
Mycelia
visible masses of mold
Magnetotactic bacteria are being studied for their potential in
wastewater treatment
Defined media is used extensively for
well characterized isolates in the lab, but may not be as useful when the nutritional requirements are unknown for a particular microbe
All of these biosafety levels follow "standard microbiological practices"
which are those practices common to all labs, which include not eating, drinking, or applying cosmetics, washing hands after working in the lab, routinely decontaminating work area.
Blood agar is an enriched medium
which nutritionally rich whole blood supplements the basic nutrients
Hyperthermophiles
with very high temperature optima, often exceeding 85-90degC
Example of unicellular fungi
yeast
Can bacteria be motile?
yes
The early Egyptians knew how to make various microbial fermented food such as
yogurt, beer, wine, bread in nearly 8,000 BC
