Microbio Exam 1

What is flagella

- Flagella are whip-like filamentous structure used for rotary motion - Both gram positive and gram negative - Aid in attachment --> Long protein filaments --> can be receptor specific --> virulence factor

What is the cell membrane made out of?

phospholipid bilayer/monolayer (on present in eukaryotes and some bacteria)

Describe electron microscopy

- Uses electron beams - more dangerous - resolution 2-200 nm - uses electromagnetic lenses - black and white images - cells are fixed - transmission and scanning - free electrons travel in waves, like light - resolving power is greater because the wavelength of the electron beams are smaller

Describe compound light microscopy (apart of light microscopy)

- Uses visible light - inexpensive - easy to use - may require stains - Uses 2 lenses (ocular and objective) - Magnification (total mag. = individual x 10) - For good resolution at high magnification, a medium with a refractive index

Describe the domain tree of life

- All three domain share common ancestor - Archea, bacteria, and eurkarya have different cell types: --> Cell membrane; Ribosome shape and size (distinct rRNA sequence); antibiotic sensitivity; cell wall structure

Preparation of specimen for light microscopy

- Basic stains have positively charged chromophore (ex. methylene blue, crystal violet, safranin) - Basic stains are attracted by the bacteria and do not stain the background - acid stains have negatively-charged chromophore - acid stains are repelled by the bacteria but stain the background - This is negative staining (allows contrast b/w slide and bacteria without killing bacteria) - no fixing is required - simple stains one use one type of chromophore and highlight the shape of the organism - Differential stains use more than one type of chromophore and bind certain cell structures (ex. gram stain (+/-) and acid-fast stain)

Who is Carl Wose

- Believed that taxonomy should be based on evolutionary relationships - Molecules (genetics/proteins) are documents of evolutionary history

Describe the Capsule (carbohydrate layer) in a gram positive bacteria

- Both gram positive and gram negative (Klebsiella) - A thin layer of glycoprotein and carbohydrates --> Protection: Prevents phagocytosis --> Virulence factor

What are the main components the outer membrane of a gram negative cell wall contain?

- Braun's lipoprotein - Porin protein: Increase permeability; size exclusion - Lipopolysaccharides (LPS) - DANGEROUS! *These polysaccaride chains form a layer that helps a pathogen resist phagocytosis by white blood cells. -->Lipid A: acts as an endotoxin; anchored in the outer membrane -->Core polisaccaride: A sugar chain that extends outside the cell --> O antigen: a polysaccharide chain of as many as 200 sugars

What is a special culture technique?

- Capnophiles are microbes that require high CO2 levels. --> A culture environment that has high CO2 and low O2 concentration resembles the intestinal tract and other body tissue where pathogenic bacteria grow.

Describe general information about Eukaryotes

- Cell type: mostly unicellular - Larger than prokaryotes - more varies cell shape - Some are pathogens

What are common structures in bacteria?

- Cell wall (Cell envelope) - S layer (Cell envelope) - Capsule (Cell envelope) - Fimbria/pili - Flagellum

Describe the S-layer in a gram positive bacteria

- Certain bacteria: Genrally, gram positive bacteria (bacillus anthracis) - Protein layer --> Protection (prevents phagocytosis) --> Virulence factor --> Contains large proteins --> Non essential for existence Note: Repeated layer of proteins; self-assembly (when together)

Compare and contrast different types of culture media

- Chemical composition: --> Defined (we know exactly what is in it) -->Complex (ingredients the cause bacteria to stay alive, but don't exactly know what is in it) -Physical nature --> Liquid (broth) --> semiliquid --> solid (agar)

Be able to draw the common bacterial shapes (use the correct terminology to to identify the shape)

- Coccus - Bacillus - Vibrio - Spirillum - Spirochete

Define species

- Collection of stains that share many stable properties and differ significantly from other groups of strains OR - Collection of organisms that share the same sequence in their core house keeping genes

What are the general functions of bacterial cell wall?

- Contributes to cell shape (porous, keeps large things out) - Protects from osmotic lysis (water breakdown) - Protect cells from toxic substances - In pathogens, can contribute to pathogenicity *Antibiotics contributes to attacking the cell wall structure

Describe darkfield microscopy

- Darkfield microscopy is used to visualize small, unstained moving targets that are: - visible in brightfield microscopy - cannot be stated by standard methods, - are distorted by fixation/staining -No fixing or staining - Yields better resoltio of cell structor Note: organisms are undistorted, thus slightly better resolution - More complicated, but better relation - more expensive - An occupation disk blocks any light that would be transmitted through the specimen form entering the objective - Only light that is scattered by the specimens is relieved by the objective, and the specimen appears bright on a dark field

Describe the different culture media (differential or selective media)

- Differential media are designed to specifically identify an organism based upon a characteristic --> Can grow other types of bacteria that do not possess the characteristic (sheep blood agar plate- picks out different between bacteria) - Selective media are designed to encourage the growth of microbes based upon a specific characteristic and to prevent microbes from growing that do not posses the characteristic --> favor the growth of the one organism over another --> Key ingredient in agar plate (MSA-high salt) that only allow certain things to grow

Why should we study bacteria

- Disease - Microbial diseases change in history (black plague in Europe, small pox in America) - photosynthesis (cyanobacteria) - Cycling elements - breaking down dead plant and animal material - food production (cheese and yogurt) - Digestion - Help protect us form pathogens/normal flora - clean up oil spills and sewage - metabolic tool boxes --> Insulin, clotting facts, rocket fuel, antibiotics

Describe mycoplasma

- Does not contain a cell wall - Smallest bacteria (500 genes) - Walking pneumonia - more closely related to gram positive genetically - Cell shape: Pleomorphic - Sensitive to osmotic shock (cholesterol --> sterols) - Antibiotic resistance (to penicillin and other B-lactam) bc antibiotics attack cell wall

List portals of entry

- Entry via the eye - oral route - Entry through skin - respiratory route - genital or sexual transmission - parental route

Describe the gram negative group: Spirochetes

- Flexible helical shape - Distinct periplasmic flagellar --> At each end of the cell, one or more flagella extend and double back around the cell body within the periplasmic space --> The spirochetes flagella twine back around the cell body, their rotation forces the entire cel to twist around, cork screwing through the medium. -Notable pathogens: --> Treponema pallidum: Causative agent of syphilis -->Borrelia burgdoferi: causative agent of lyme disease

How do we measure virulence

- LD50 (lethal dose) - killing; amount of pathogen it has to kill 50% of population - ID50 (infected dose) - how many people you have to infect to get 50% of the rest infected *Is a microbe with an LD50 of 5x10^8 more or less virulent than a microbe with an LD50 of 5x10^8 virulent --> takes a lot more of LD50 virulent

Describe the gram negative group: Chlamydias

- Lack peptidoglycan in cell wall -->Evolved independently of the mycoplasmas, and their alternative cell forms show very different environmental adaptations - Obligate intracellular pathogens --> Pneumonia, blindness, Clamydia (Pelvic inflammatory disease - inflammation of the fallopian tues and ovaries - can leave permeant adhesions (fibrous tissues across the organs), common cause of infertility) - EB and RB (life cycle of Chlamydias) --> Different life cycles chlamydia goes though --> EB - less metabolic stage, escapes one cell and goes to the other --> RB - metabolically active stage

Name of non-spore formers

- Lactobacillus: Make yogurt and cheese - Listerna: Pathogen, grows at 4 C - Mycoplasma: no cell wall - Enterococcus: Normally found in intestinal tract; can cause UTI - Staphylococcus: Epidermids (species): all over human body; acres (species): Pathogenic causes diseases - Streptococcus: Pyogenes: cause strep throat

Describe the peptidoglycan formation

- Linked together by enzymes called transpeptidase - Strong enough to retain thee shape and integrity yet relatively porous and elastic *Note: Limited amount of transpeptidase = limited amount of cell wall creation

Name some of the fields in microbiology

- Medical microbiology - publics health microbiology - immunology - molecular biology, microbial genetics, and bioinformatics

General information eurkarya (Fungi)

- Not plants! Non photosynthesis - Energy source: absorb organic carbon from environment - Cell wall of chitin - Sexual and asexual reproduction - some are pathogens MAJOR TYPES: Unicellular yeast, multicellular molds, mushrooms

Describe the gram negative group: Bacteroidetes

- Obligate anaerobes (incapable of growing in the presence of oxygen) - Common inhabitants of human colon --> These bacteria actually communicate with our immune system, telling our immune cells which response to make while avoiding immune defenses that could harm them - Important role in the gut -->Their main source of energy is fermentation of a wide range of sugar derivative from plant material --> Removes side chains from bile acids allowing them to return to bloodstream

What is a microbe?

- Organism that usually cannot be seen with a naked eye --> usually less than or equal to 0.1 mm --> Some microscopic - Relatively simple structure; lack highly differentiated cells and distinct tissue - diverse groups -->Prokaryotic and eukaryotic cell types -->Unicellular and multicellular organisms --> cellular and non-cellular life

What are the different types of flagella

- Peritrichous - Polar - Monotrichous - Lophotrikhous - Amphitrichous

Describe the gram negative group: Cyanobacteria

- Photosynthetic bacteria --> Only bacteria that produce O2 gas, a by-product of oxygenic photosynthesis --> Fixes much of the carbon dioxide for consumers in ecosystem as well as biospheres nitrogen. --> chloroplast thought to have evolved this type of bacteria (plant cells cannot live without chloroplast because it has become so depended on it) --> Cyanobacteria commonly appear green because of the predominant blue and red absorbent by chclorphils. Essentially the same chlorophylls are found in plant chloroplast, which evolved form internalized cyannoacteria that became endosymbionts. - Also responsible for large scale blooms at sea

What do all bacteria have?

- Plasma membrane - ribosomes - DNA - Nucleiod

What is peptidoglycan?

- Polymer of identical subunits (composed of carbohydrates and amino acids) - Carbohydrates: NAG, NAM - Amino Acids: connected to NAM; alternative D- and L- amino acids (D-amino acids are not found in proteins)

Describe general information about: Domain Archea

- Prokaryotic cell type - Many similarities to bacteria --> lack nucleus and complex cell structure, small cell size, simple shapes, high metabolic diversity, asexual reproduction, can grow in wide variety of conditions - Distinct form bacteria, more similar to Eukaryotic cells biochemically and genetically - Does not have a peptidoglycan cell was if a cell wall is present. - Plasma membrane contains Ether linkages

Describe the anaerobic growth media and methods

- Reducing media is used to culture obligate anaerobes because it contains chemical that deplete O2 in the culture medium. - Anaerobic jars and anaerobic changers are used

Bacteria need to be able to...?

- Sense and respond to their environment - Metabolize - Grow and reproduce

Explain the advantages of biofilms

- Share nutrients - Shelter - Increased opportunity for conjugation Human health - 70% of infections involve biofilms - form on catheters and medical devices - more resistant to antimicrobial agents

Describe general information about: Domain Bacteria

- Single-celled organisms - Microscopic - Lack a nucleus - Cell membrane: lipid bilayer, specifically phospholipids help together by Ester bonds - Peptidoglycan Cell wall - Non-pathogenic/pathogenic - Extremely wide range of food sources - Reproduce asexually

Discuss the various host factors involved in diseases

- The frequency of a disease is also a characteristic that is used for classification - An endemic disease is constantly present in a population - An outbreak occurs when cases of disease rises above endemic level - An epidemic disease is exhibited geographical area widens and can number rise rapidly. - A pandemic disease is an epidemic disease that occurs worldwide.

What is the refraction index

- a measure of how greatly a substance slows the velocity of light - light bends when it shrinks a surface at an angle - A different ein refractive index is necessary to see specimens - Stains have different refractive indexes than the sample and are necessary with brightfield microscopes to increase the contrast between the specimen and its medium

Describe Archea's extremophiles

- includes many extremophiles (live in extreme environments or have unusual metabolism) 1. Methanogens - Strict anaerobes (wetland sediments, animal guts, land fills) 2. Extreme halophiles - Dead sea, great salt lake 3. Extreme thermophiles - Yellow stone, hydrothermal vents 4. Extreme acidophiles - Also non extreme Archaea: Soil, freshwater, ocean; no known pathogens

Preparation of specimens for light microscopy

- most samples appear colorless because of a lack of intrinsic contrast - FIX the sample (fixation): prepare smear, air dry, heat fix - stain the stain

Describe light microscopy and the different types of light microscopy

- resolves images of individual bacteria based on their absorption of light - Dark object (partly transparent) appears against bright background - Compound light microscopy (brightfield): The specimens is commonly viewed as a dark object against a light filled field or background - Darkfield microscopy: a type of light microscopy that produces brightly illuminated objects on a dark background

Describe cellular microbes

- viruses, viroids, virusoids (cells notice its DNA and replicate it) - Prions: Proteins that cause disease, act as infectious particles

Describe the phases of microbial growth, and breifly describe binary fission Be able to calculate bacterial growth

1. Cell elongates and DNA is replicated 2. Cell wall and plasma membrane begin to constrict 3. Cross-wall forms, completely separating the two DNA copies 4. Cells separate Binary fusion: Most bacteria reproduce by binary fusion; bacteria reproduce asexually; each become 2 cells

What are the 6 functions of LPS?

1. Contributes to the negative charge (core polysaccharide) 2. Stabilize outer membrane surface (Lipid A) 3. Aid in attachment to surfaces 4. Create permeability barrier 5. Protecting pathogenic bacteria from host immune response (O antigen) 6. LPS is an endotoxin --> septic shock (Lipid A)

Describe the gram positive bacteria groups

1. Firmicutes: **Low G/C gram positive - Most are heterotrophs with thick cell walls that resist dying - Many, such as Clostridium, form dormant endospores - Grow as well-defined rods or cocci - Some species of Firmicuties form endospores, inert heat-resistant spree that can remain viable for thousands of years. The endospores also resist dying, high-energy radiation, freezing, and chemical disinfectants 2. Antinotacteria **High G/C gram positive, including major - The acid-fast property is associated with using cell wall lipids - Figure 10.9 - Dark blue droplets on the colonies contain secreted antibodies on strepetomyes --> Streptomyces bacteria grow as filaments the develop specialized cells at their tips called arthrosproes, which are released and disperse in the air to form new colonies --> The mycelia of streptomycin and other actinomycetes produce molecules we use as antibiotics - Used as a defense mechanism against other bacteria - These antibiotic producing bacteria prevent other antibiotics to kill them. - They become antibiotic resistant by picking genes up from other bacteria that have antibiotic genes - Other filamentous actinocyctes are pathogens. For example, Nocardia species are opportunist that can cause pneumonia in hospital patients. Examples of Actinobacteria 1. Mycobacterium -Do not gram stain well - action bacteria include the causative agent of tuberculosis (M. tuberculosis) and leprosy (M. leprae) --> cells of M. tuberculosis can be deleted by the acid-fast stain as tiny rods --> M. tuberculosis has exceptionally thick, complex membrane that include some of the longest-chain acids - Mycolic acid (a polymer of sugar build onto the peptidoglycan) --> forms a waxy coat that impacts the entry of nutrients through porins and thus slows the growth rate, but also protects the bacterium from host defenses and antibiotics --> For this reason, the curve for tuberculosis requires an exceptionally long course of antibiotics therapy

What are some endospore genus

1. Genus Bacillus - Kills caterpillar pets by infection their digestive system tract; the high pH of the insect gut interior activates the crystalline toxin released by the bacteria. - *Bacillus species grow best by aerobic respiration; they form large, cream-colored colones on a nutrient agar plate exposed to air - To produce endospores, the cell divides near one of its poles, instead of at the cells equator 2. Genus Clostridium - Strict anaerobes (obligate anaerobe) - The growing endospore swells the end of the cell, giving the cell shape like a club. - Including the causative agents of two-well known diseases tetanus (C. tetani) and botulism (C. botulinum)

List four stages of an infections disease and describe each stage stains and symptoms; morbidity vs. mortality

1. Incubation Period: Period after pathogen entry, before signs and symptoms; you probably have no idea you're infected. 2. Prodromal stage: onset of signs and symptoms; not clear enough for diagnosis; beginning to show early signs of this pathogen 3. Period of this illness: disease is most severe, signs and symptoms; display al signs and symptoms 4. Covalenscence: signs and symptoms begin to disappear patient recovers Note: Morbidity: refers to the existence of a disease state and the rate of incidence of the disease; sickness Mortality: measure of how patience die from disease

Describe the gram negative group: Proteobacteria

1. Proteobacteria Pathogens (cause disease) - Family - Enterobacteraiceae --> E.coli: grows normally in human intestines, feeding on our mucous secretion and producing vitamin K; some stains are PATHOGENIC --> Salmonella enterica: Diarrhea, fever, and abdominal cramps --> Yersinia pestis: Cause of Bubonic plague - Members from other families --> Bordetella pertussis: Whooping cough (illness prevented by immunization) -->Helicobacter pylori: Ulcers --> Vibrio cholerae: Cholera --> Neisseria menigitidis: Can cause meningitis --> Neisseria gonorrhoeal: STD gonorrhea

What are the three major types pf eurkarya (Protist)

1. Protozoa - Energy source: organic carbon obtained from ingesting smaller cells/ particles - motile - no cell wall - Sexual and or asexaul reproduction - Some independent, some parasites 2. Algae - Energy source: light - Cell wall: cellulose - photosynthesize

What is the molecule of choice and why?

16s rRNA - Because all living organisms have it; associated with ribosomes - Genes slowly mutate over time

Describe the fundamental Host-Pathogen Interactions

A Productive Infection: - agent identity - virulence of agent (decrease the amount of damage that a particular microbe can cause) - means of exposure to age (have to be exposed by a microbe in a certain way; i.e.. flu virus breath it in) --> breath, ingest it, touch, exchange of body fluids - dose of age - susceptibility of host to agent (amount of times you come in contact with (dosage) depends on if you'll get infected not - depends of microbe)

What happens when the environment limits growth?

A bacteria growth curve represents the growth of a microbe after a culture is inoculated

Why do we study the cell wall structure?

Antibiotics --> microbial product or derivative that inhibits/kills microbes *We have to develop antibodies that are designed to kill bacteria cells, and not human cells --> target things particular to bacteria cells --> This is why we have side effects, the medication effects our original cells and not only the bacteria cells

What cells contain a monolayer?

Archea cells - some have bilayer, some have monolayer (both head groups, with long tails - makes more permeable - allowed to survive in different environment

What are the three domains of life?

Bacteria, Archea, Eukarya

Compare and contrast cell structure of eukaryotes versus bacteria

Bacteria/Prokaryote - Small cell size - DNA organized in nucleic throughout the cytoplasm - Small genome - Circular chromosomes, although may have multiple circular and linear chromosomes - Chromosomes replicate and segregate during cell growth - Few intracellular membranes - No intracellular endosymbiotic organalles - Cell wall composed of peptidoglycan - Rotary flagella for motility driven by proton motive force Eukaryotes - Wide range of cell size, from very small to very large - DNA contained in nucleus, enclosed by nuclear membrane - Wide range of genome size, including very large - Linear chromosomes (in nucleus, mitocondria (driven from bacteria)) have one circular chromosome - Chromosomes segregate by mitosis and meiosis, after replication during interphase - Many types of intracellular membranous organelles - Mitocondria and chloroplast are organelles that evolved from endosymbiotic bacteria - Cell walls of plants and fungi composed of various carbohydrates, but never peptidoglycan - Whiplike flagella for motility, with microtubule contraction driven by ATP

Describe biofilms and endospores

Biofilms - Microbes often live in communities as biofilms - A biofilm is a mass of bacteria that stick to and multiply on a solid surface - Biofilms can be constricted by a single spices or by multiple collaboration species and can form on a range of organic or inorganic surfaces - Biofilm is build up that bacteria secrets; waste products form bacteria benefits other bacteria - The matrix of the biofilm is composed of polysaccharides, proteins, and nutrients - As more and more cells bind to the surface, they can begin to communicate with each other by sending and receiving chemical signals in a process called QUORUM SENSING - Individual cells continually make these chemical signal molecules, but once the population reached a certain number the chemical signals reaches a concentration that the cells can sense ***NOTE*** - Only certain types of bacteria produces biofilms - Creating different kinds of gradients within a biofilm slows down O2 and nutrients (not only antibiotic resistant) - Importance? When bacteria get together like this, they start swaping genetic information - This is bad because they create new strains that is drug resistant and there may not be cure for it. Endospores - Endospores are specialized "resting" forms of cells formed during sporulation form vegetative cells - Endospores are highly durable, dehydrated from the cells with a "spore coat"that can survive extreme heat, lack of water, and exposure to chemical and radiation - Endospores can survive for millions of years to germinate - Only formed by gram-positive bacteria under extreme circumstances - Bacillus anthracis, Clostridium tetani, C. botulinum

Acid fast cell wall (staining techniques, decolorizes with acid alcohol)

Cell wall staining: - Waxy cell wall repel most dyes - Acid fast stain: lipid soluble dye; retain the dye when whaled within acid alcohol

What is refraction

Describes the bending of light in a medium

*Compare and contrast the methods for determining bacterial counts.

Direct Meausremet of Microbial Growth - Plante count is the most common technique --> measures viable cells --> takes time (overnight) - A colony forming unit could be a single cell or a clump of cells that give rise to a colony on a plate - A serial dilution is performed to avoid overcrowding on a plate, which leads to inaccuracies. This goal is 30-300 colonies/plate - A plate count is performed after either pour plates (liquor agar and mix bacteria with it) or spread plate (solution of bacteria and its spread across plate) are created - Pour plate may damage microbes, and sub-surface growth is not optimal for determining colony morphology --> advantage: a lot of dead or alive bacteria, so it'll only count live bacteria --> disadvantage: patients - Filtration method is necessary when the numbers of microbes in a sample is small --> the microbes are concentrated on the filter and then transferred to a plate for counting --> advantage: small concentration of bacteria; they have to grow (live bacterium) - Microbial cells are directly counted in a known volume in a direct microscope count --> This method is quick, but counts live and dead cells and is not appropriate for motile microbes --> advantage: straight counting; grade system; quick --> disadvantage: In low concentration of bacterium; not enough bacterium; non-mobile Indirect Measurement of Microbial Growth - Measure turbidity is an indirect method to estimate cell count - This method relies upon a spectrophotometer and correlates absorbance and turbidity (cell density) - This is a quick method, but must occur during log phase (a period of cell culture during which bacteria grow exponentially at their maximum possible rate based on the growth condition) - during turbidity, determine concentration of bacteria by shining light against tube (measure amount of absorbance) -->advantage: doesn't take very long -->disadvantage: not an exact count, if theres not a certain level of absorbance, this system will not work well.

What is the organization of phylum tree

Domain --> Kingdom --> Phylum --> Class --> Order --> Family --> Genus --> Species

What is an endospore, what types of bacteria form endospores?

Endospores are resistant asexual spore that develops inside some bacteria cells Gram positive: Firmicutes (Bacillus, and Claustidium)

Define/give examples of etiology, endemic, epidemic, and pandemic

Etiology: the cause of disease Pathogenesis: how the disease develops

Acid fast cell wall: What types of bacteria have acid-fast cell wall?

Genus: - Mycobacterium: Tuberculosis, leprosy - Nocardia: Healthy mouth flora

Distinguish major phylum of Gram-positive bacteria from Gram negative bacteria

Gram positive bacteria: - Firmicutes - Actinobacteria Gram negative: - Proteobacteria - Bacteriodetes - Spirochetes - Chlamydia

Compare and contrast that structure of gram positive cell walls vs. gram negative (draw, describe the functions of the cell wall the major components, discuss its importance in as a target for antibiotics)

Gram-Positive Cell Wall - Thick peptidoglycan layer - Small periplasmic space (very few proteins) - Teichoic acid --> Required (shape, cell division, attachment/pathogenicity) Gram Negative Cell Wall - Thin peptidoglycan layer - Large periplasmic space --> Contains enzymes and protein: Nutrient acquisition, ETC, peptidoglycan synthesis, and modification of toxic compounds - Contain an outer membrane (lipoproteins, poren proteins and LPS)

Acid fast cell wall: Impact of cell wall structure

High lipid content - 20x less permeable to hydrophilic compounds than other bacteria - Generally slow growing - Resistant to many antibiotics including penicillin Note: - Sensitive to osmotic lysis - Plasma membrane of bacteria that lack a cell wall are more rigid; die of osmotic shock, must have cell wall to survive - more closely related to gram positive genetically - Antibiotics attack cell wall

Discuss direct and indirect modes of transmission (formats, resovior, aerosol. Be able to list one resovior of human disease along with the organism it harbors)

Indirect transmission: Microbes can be transmitted indirectly by inanimate objects (fomites), by vehicle transmission or by insect vector. Direct transmission: Microbees can be transmitted by direct contact or by aerosolization (eg. sneezing, influenza) Vehicle transmission: Some microbes can be transmitted through contaminated fomites, food, water, or air Insect Vector: Microbes can be transmitted form animal to animal (and to humans) by insect vectors. Vertical transmission: Transmission of an infectious agent from an insect to its offspring. *Pathogens can be transmitted both directly and indirectly through contact with a reservoir, which describes that natural host of that pathogen (may or may not make that host sick) *Often the natural reservoirs for a human infectious disease are animals such as bats for SARS and rats for plague.

Define infectious disease,

Infectious disease: are caused by microbes - A disease is a disruption of the normal structure or functions of any part, organ, or system that can be recognized by a characteristic set of syphons and signs. The ability cause disease is called pathogenicity (when there is a change from a state of health) - caused by a microorganism (bacterial, viral, or parasitic) that can be transferred from one host to another Ex. Pneumonia (infectious disease) - caused by microbes

Describe each phase of growth. which comes first, second....last

Lag phase: - occurs because cells do not immediately reproduce a new medium --> No growth (bacteria is adjusting) --> Cells taken from an aged culture may be damaged and required time for repair before they can replicate - Cells do not dormant in lag phase - cells preparing for new growth medium Log phase (exponential growth): - Once cells have retooled their physiological to accommodate their new environment, they begin to grow exponentially and enter log phase - Exponential growths is balanced growth, where all cell component are synthesized at constant rates in relation to each other - cells grow at the maximum rate possible based on the medium and growth condition provided (such as temp, pH, and osmolarity) - Cells are larges at this stage of growth - Generation time reaches a constant - The bacteria growth curve is a line Stationary phase: - The stationary phase exhibits a balance between cell death and cell growth - The exhaustion of nutrients, accumulation of waste products, and harmful pH change is usually responsible - At this point, the growth curve levels off - As they enter this phase, many bacterial pathogens develop resistance to antibiotics and host defense Death phase - The death phase exhibits more cell death that cell growth - Like growth rate, the death rate, the rate at which cell dies is exponential - Exact death rates are difficult to define because mutations arise that promote survival, and some cells grow cannibalizing others.

What is the difference between living and non living microbes?

Living: Have plasma membrane; capable of making their own ATP; contain ribosomes (synthesis protein) Non-living: Gets their energy form host cell

Discuss different methods used to assign bacteria to a particular taxonomic group

Microbe taxonomy (classification) - Placed in taxonomic level so that each level not only includes the traits that define the rank about it but also a new set of more restrictive traits. - Classical characteristics: Morphological, Physiological, Biological, Ecological - Molecular characteristics: --> Nucleic acid based composition (DNA/RNA relationship) --> Nucleic acid hybridization: 70% identical means same species --> Nucleic acid sequencing --> Genomic fingerprinting

What is the purpose of the cell membrane?

Protection, cell to cell communication, contains proteins (carriers, channels)

Discuss motility and chemotaxis

Motility - Both prokaryote and eukaryote contain flagella --> eukaryotes- sperm cells --> prokaryotes - can move clock (stops forward motion so cell tumbles and changes direction) or counterclockwise (moves cell towards attractant) in a motor like motion, propelling flagella - Proteus spp. can 'swarm or display rapid wavelength movement across a solid culture medium Flagella - Motility leads to taxis, the movement towards or away from a stimulus: --> Chemotaxis: Chemical movement --> Phototaxis: Light movement --> Attractant --> repellent

Bacteria with atypical or absent Cell Walls: Acid fast cell wall

Mycobacteria and Nocardia

List examples of bacteria whose cell wall deviates form the typical +/- (When possible describe the unique cell wall components these bacteria contain; discuss the impact of these differences)

Mycobacterium contains an acid fast cell wall and is the main bacteria for turboquosis and leprosy. Nocardia also has an acid fast cell wall and is present in a healthy mouth flora. Mycoplasma does not contain a cell wall, is antibiotic resistant, and is sensitive to osmotic shock

Bacteria with atypical or absent Cell Walls: Do not contain a cell wall

Mycoplasma

Do all organism have a cell wall?

No, cell wall's are only present in bacteria, prokaryotes, arches, fungi, and pathogens

Which domain of life do microbes belong in?

None bc they're all non living organisms - Microbes are pathogenic non-living (has nucleic acid)

List common structures that most bacteria have and describe the fuctions

a. Diplococci, Streptococci b. Tetrad c. Sarcinal d. Staphylococci (All asexual reproduction)

What are the 4 major kingdoms of Domain Eukarya

Protist, Fungi, Plant, Animal

Compare and contrast pathogens, opportunistic pathogens, and nonpathogenic bacteria

Pathogen: is a microbe that causes disease An opportunistic infection is an infection caused by bacterial, viral, fungal, or protozoan pathogens that take advantage of a host with a weakened immune system or an altered microbiota

Define micro biome, pathogenicity, infection, virulence, LD50 and ID50

Pathology: the study of disease Infection: occurs when pathogens invade or colonize the body Disease: occurs when there is a change fro a state of heath Microbial: All microbes in the human body are made up of mutualistic relationship between human body and microbe. All non pathogenic.

The crucial art of Diagnosing

Patient History - Chief complain: a statement of what prompted the patient visit - History of present illness: a chronological summary of the current illness. - Medical history: a list of prior illness - Family history Differential: List of possible causes

What do gram positive and gram negative bacteria have in common?

Peptidoglycan layer in cell wall

Describe in detail what physical requirements affect microbial growth and how. (Know the terms associated with various physical conditions (halophile, mesophile, ect...)

Physical Requirements for growth: - temperature, pH, Osmolarity, Oxygen, pressure Temperature: - Certain organisms can survive 'extreme' temperatures --> Change in temperature impact every aspect of microbial physiology, including membrane fluidity, nutrient transport, DNA stability, RNA stability, and enzymatic structure and function. --> Every organism has an optimal temperature at which it grows most quickly, as well as minimum and maximum temperatures that define the limits of growth. --> At cold temperatures, growth ceases because enzymatic processes become too sluggish and the cell membrane less fluid. --> Heat increases molecular movement within proteins. Too much or too little movement will interfere with enzymatic reaction. - By their range of growth temperature, microorganism can be classified as linking hot (thermophiles), cold (psychrophiles), or in between (mesophiles) --> Thermophiles have adapted to growth at high temperatures typically 55 C and higher --> Psychrophiles hare microbes that grow at temperatures as low as 0 C, but their optimal growth temp. is usually around 15 C --> Mesophiles optimal range between 20 C - 40 C with a min of 15 C and max of 45 C (E. coli) -- easy to grown and human pathogens are mesophiles Oxygen Concentration 1. Obligate anaerobe: Cannot grow with presence of O2 2. Facultative anaerobes: Can live with or with out O2 because they come equipped with enzyme that destroy toxic oxygen byproducts 3. Aerotolerant anaerobes: sub class of facultative organisms; use only fermentation (not aerobic fermentation) to provide energy 4. Strict anaerobe: dies int he least bit of oxygen 5. Microaerophilic: will only grow at low O2 concentrations; needs O2 by can only grow at atmosphere level NaCl concentration - Some microbes are halophiles (requires high salt concentration) --> Most bacteria prefer NaCl concentration between 0.05-1M but halophilic microbes grow optimally at 0.85-3.4 M --> E. coli can grow in high concentrations pH - Most human pathogens thrive at 7.4 (blood) - Some bacteria are acidophiles (bacteria and arches that live in acidic environments - Too much acid or base is harmful to cells. Despite that sensitivity to pH extremes, living cell can tolerate a greater range of H+ concentration than of virtually and other chemical substances. ** Heliobacter pylon causes stomach ulcers, thrive at pH 1 **Lactobacillus maintains vaginal pH at 3-5, not a lot of bacteria in this environment, this bacteria eliminates a lot of bacteria growth. Pressure - Barophiles: Microorganism at location deep within ocean floor that have adapted to grow at oppressively high pressure --> actually require elevated pressure to grow, whereas barotolerant organisms grow over the range of 10-500 atm., but grows fall off there after.

What is the difference between simple stains vs. Differential staining?

Stimple stains: - 1 degree only - use can determine size, shape, and aggrangement of bacteria Differential stains - 1 and 2 degree - use can determine size, shape, arrangement, and structural feature

Define strain/ type strained

Strain: - descended from a single, pure microbial culture - vary from each other in many ways - biovals: differ biochemically and physiology - morphavars: differ morphologically - serovars: differ in antigenic properties Type strain - Most studied - Usually one of the first strains of species studied - Often most fully characterized - Not necessarily most representative member of species

List and describe each of the different "links" that are needed to contribute to a productive infection

Symbiosis: an association of two or more species of organism (smaller organisms --> symbiont; larger organism --> HOST) - Commensal symbiosis: organisms that take, but do not give sustenance form their host. - Mutualistic symbiosis: microbiota derive and give benefit to their host; mutualistic relationship. - Parasitic symbiosis: microbe is harming out HOST cells When parasites grow/multiply on the host, the host has an infection: --> Causes an infectious disease - any change in normal health function --> The host is an opportunity of the microbe to obtain protection, nutrients, and energy (bacteria have developed mechanisms to exploit the host --> resulting in disease)

Describe in detail what physical and chemical requirements affect microbial growth and how.

The Requirements for Growth - Microbial growth refers to the number of cells, not the size of cells - Nutrients, moister/temperature limits bacteria growth Chemical Requirements: - Essential Elements (compounds a microbe cannot make itself by must gather from its immediate environment): Carbon, Nitrogen, Phosphorous, Hydrogen, Oxygen, and sulfur. They are needed in large quantities (macronutrients) because they make up the carbohydrates, lipids, nucleic acids, and proteins of the cell. All cell use these building blocks but build themselves in different ways. Obtaining carbon: Autotrophy and Heterotrophy * Metabolic groups; each group converts carbon to a form that the other groups can use - Heterotrophs: --> Rely on other organism to make organic compounds, such as glucose, that they use as carbon sources. --> All bacterial pathogen are heterotrophs --> During heterotrophic metabolism, organic carbon sources are disassembled to generate energy and then reassembled to make cells constituents such as proteins and carbohydrates. --> This process converts a large amount of the organic carbon source to carbon dioxide, which is them released into the atmosphere. --> If left alone, heterotrophs would deplete the world or organic carbon sources (converting them to unusable CO2) and starve to death. For life to continue, CO2 myst be recycled. - Autotrophs --> Use the CO2 by heterotrophs to make complex organic compounds (C, H, and O) --> The organic compounds synthesized by autotrophs can later be used as carbon sources by heterotrophs

Describe electron microscopy (SEM/TEM)

Uses beams of electrons to resolve details several orders of magnitude smaller than those seen with light microscopy (ex. EM can resolve the shape of ribosomes and viruses)

Describe the formula needed to calculate the number of bacteria

Y = 2n Y= number of cells in the colony n= number of total generations * you may beed to calculate the number of generations, which is based upon the total time and generation (# of generations = total time/generation time)

Can the cell wall be used to differentiate between organism?

YES! Ester bonds (eukarya and bacteria), ether bonds (archea) how heads bond together

Do all living organisms have a cell membrane?

Yes, the cell membrane is located outside of the cell, surrounding cells (but is not always the outer most layer)

What the most abundant cells on earth

prokaryotes (humans are 90% prokaryotes

What is resolution

the ability to distinguish between two points - affected by 2 factors: wavelength of light being used and amount of light - the shorter the wavelength of light, the greater resolution - the limit of resolution, or resolving power, for light microscope is 0.2 um (200x)