Microbiology Chapter 4

Reflects biosynthetic capabilities E. coli synthesizes all _________ Neisseria unable to synthesize many________ Termed fastidious: ___________

*cellular components from glucose, has wide metabolic capabilities *requires numerous growth factors *have complicated nutritional requirements

Psychorophile

-5 to 15 C -arctic and antarctic regions

Psychrotroph

20-30 C-food spoilage

Most microbes are neutraphiles pH ranges from

5 to 8, optimum near pH of 7

Alkaliphiles grow optimally at pH above

8.5

Growth factors: some microbes cannot synthesize certain molecules unless certain growth factors are present

Amino acids, vitamins, purines, pyrimidine

Nitrogen required for amino acids, nucleic acids may use ______ (some convert nitrate to ammonia), and ______ _______ is important

Ammonia Nitrogen fixation

H. Pylori grows in stomach and produces urease to split urea into

C02 and ammonia to decrease acidity of surroundings

Obligate Anaerobe: Growth characteristics

Cannot grow when 02 is present

Function: Nitrogen

Component of amino acids and nucleic acids

Function: Carbon, oxygen, and hydrogen

Component of amino acids, lipids, nucleic acids and sugars

Function: Phosphorous

Component of nucleic acids, membrane lipids and ATP

Function: Sulfur

Component of some amino acids

Extreme halophiles are greater than or equal to 9% and examples are

Dead sea, Utah's salt flats

Obligate Anaerobe: typical mechanism to protect against reactive oxygen species

Does not produce super-oxide dismutase or catalase

Aerotolerant Anaerobe: Use of O2 in energy harvesting processes

Does not use 02

Obligate Anaerobe: Use of O2 in energy harvesting processes

Does not use 02

Facultative anaerobe do ____ at the bottom and ___ at the top

Fermentation ( low 02) Respiration (high 02) (so grows in more concentration at top of tube)

Facultative anaerobe: Growth characteristics

Grows best when O2 is available but also grows without it

Aerotolerant anaerobe: Growth characterisitics

Grows equally well with or without 02

Microaerophile: Growth characteristics

Grows only if small amounts of 02 are available

Obligate Aerobe: Growth characteristics

Grows only when 02 is available

Some microbes withstand or even require high salt content and are called

Halotolerant or Halophiles

Carbon source distinguishes different groups

Heterotrophs use organic carbon where Autotrophs use inorganic carbon like C02 (carbon fixation)

Chemolithoautotroph: energy source and carbon source

Inorganic Chemicals (H2, NH3, NO2-, Fe2+, H2S) & C02 (bacteria or Archea that live in hostile environments)

Chemotrophs extract energy from chemicals examples:______ common sources are __________, Some prokaryotes use inorganic chemicals such as ____________

Mammalian cells, fungi, many types of prokaryotes Sugars, amino acids, fatty acids hydrogen sulfide, hydrogen gas

Nitrogen fixation takes

N2 and turns it into ammonia NH3 (only prokaryotes can do this)

Number of cells in population at t=time equals orignal number in population times 2 to the number of divisons

Nt = No X 2^n Nt = 10 X 2^12 Nt = 10 X 4096 Nt = 40,960 (in 4 hours) 12= 3 divisions in 4 hours

Lag phase

Number of cells doesn't increase but begin synthesizing enzymes required for growth, delay depends on conditions

Chemoorganoheterotroph: energy source and carbon source

Organic compounds (sugars, amino acids, etc.) & Organic compounds (humans)

Hypo-soln: H20 leaves environment to go into cell and is called

Osmolysis

Functions of iron

Part of certain enzymes

Acidophiles grow: optimally at pH below 5.5

Picrophilus oshimae has optimum pH of less than 1

Phototrophs obtain energy from sunlight : EX:

Plants, algae, photosynthetic bacteria

Facultative Anaerobe: typical mechanism to protect against reactive oxygen species

Produces super-oxide dismutase and catalase

Obligate Aerobe: typical mechanism to protect against reactive oxygen species

Produces super-oxide dismutase and catalase

Aerotolerant Anaerobe: typical mechanism to protect against reactive oxygen species

Produces super-oxide dismutase but doesn't produce catalase

Microaerophile: typical mechanism to protect against reactive oxygen species

Produces super-oxide dismutase but doesn't produce catalase

Key consideration that influence microbial growth

Required elements, growth factors, energy sources, nutritional diversity

Function: Potassium, magnesium and calcium

Required for the functioning of certain enzymes, additional functions as well

Microaerophile: Use of O2 in energy harvesting processes

Requires 02 for respiration

Obligate Aerobe: Use of O2 in energy harvesting processes

Requires 02 for respiration

Photoautotrophs: energy source and carbon source

Sunlight & C02 (plants)

Photoheterotrophs: energy source and carbon source

Sunlight& Organic molecules (algea, green & purple bacteria)

Energy sources

Sunlight, chemical compound

Generation time

Time it takes to double, depends on species and environment

Facultative Anaerobe: Use of O2 in energy harvesting processes

Uses O2 for respiration if available

Neutrophiles can use food can be preserved by increasing

acidity

Secondary metabolites production after primary metabolites occur

as nutrients are depleted and wastes accumulate

Prokaryotes divide by

binary fission

Prokaryotes often grow in close association with many different species and can be cooperative

can foster growth of species otherwise unable to survive (strict anaerobes can only grow in mouths who consume o2, metabolic waste of one can survive as nutrient of other) or they can synthesize toxins to prevent growth of others

Exponential phase

cells divide at constant rate, where generation time is measured, most sensitive to antibiotics, production of primary metabolites (commercial importance)

Pure cultures using aseptic technique-to minimize potential contamination

cells grown on medium-nutrients dissolved in water, broth or solid gel

Complex conditions of nature have an effect on microbial growth and behavior

cells sense change and adjust to surroundings, synthesize compounds useful for growth, can live in communities-called biofilms (causes slipperiness of rocks in stream bed, slimy "gunk" in sink drains, scum in toilet bowls, dental plaque)

Reactive oxygen species are damaging to

cellular components

Organisms that are fastidious are organism that require a

complex medium that provide heme or etc. with complex organic molecules (more they require the more fastidious they are

Almost All cells also produce Catalases which help

convert H202 and H20, with the exception is aerotolerant anaerobes, makes for useful test (if not catalase then proctase)

Trace elements usually available of

copper, cobalt, zinc, molybdenum, manganese

Aerotolerant Anaerobe: can tolerate 02 but

could really care less if it is there or not ( why there is growth in all parts of the tube)

bio-films can do many things

dental plaque, infections, clog pipes and drains, cause to be more resistant, or can be helpful-waste water treatment

Carbon makes up 50% of

dry weight of cell

Chemoorganoheterotrophs (also termed chemoheterotrophs, chemoorganotrophs

energy and carbon from organic compounds

Chemolithoautotrophs (also termed chemoautotrophs, chemolithotrophs):

energy from inorganic compounds; carbon from CO2

Photoautotrophs

energy from sunlight; carbon from CO2

Photoheterotrophs

energy from sunlight; carbon from organic compounds

Prokaryotes can live in all environments, comfortable in humans or in harsh environments called

extremophiles - archaea

Heterotroph

gets organic carbon from environment because cant use C02 and make own sugar from organic carbons

Obligate anaerobe do

grow near the bottom of the tube (far away from any contact with oxygen)

oxygen requirements: boil nutrient Agar to drive off O2, cool to just above solidifying temperature inoculate and gently swirl

growth demonstrates organism's O2 requirements

Almost all organisms growing in the presence of oxygen produce an enzyme called super-oxide dismutase which

inactivates super-oxide by converting to 02 and H202. (reactive molecules)

5 phases based on the growth curve

lag phase, exponential (log ) phase, stationary phase, death phase, phase of prolonged decline

Iron, phosphorus often is

limiting (because Phosphorous is not in protein or carbohydrates normally

Prokaryotes require nutrients to synthesize cell components such as

lipid membranes, cell walls, proteins, nucleic acids=which subunits composed of chemical element s including carbon and nitrogen

The required elements are

major elements that make up the cell components

Autotroph

make their own sugar via taking C02 from H20 or AIR

Prokaryotes have remarkable

metabolic diversity

Chemostats can maintain continuous growth by drip fresh medium into culture chamber and equal volume is removed (cell wastes)

nutrient content and speed of addition can be controlled-constant growth rate and cell density, uniform population for study

Stationary phase

nutrient levels too low to sustain growth, numbers remain constant, some die and release contents so others can grow

Bio-films have architectures or channels through which

nutrients and wastes pass and cells can communicate by synthesizing chemical signals

Cells must have mechanism to protect from reactive oxygen species but

obligate anaerobes typically do not (have the enzymes to get rid of excess 02)

4 categories

photoautotrophs, chemoautotrophs (chemolitotrophs), chemheterotrophs, photoheterotrophs

Hyper-soln: water moves out of cell and is called

plasmylysis (press together or shrink)

Exponential growth

population doubles each division

Pure culture

population of cells derived from a single cell -study of single species

Salt and sugar are used to

preserve food

Sulfur is found in

proteins, cysteine and methionine

Microaerophile

require O2 a relatively low levels

Halophiles

require high salt concentrations ( marine bacteria 3%)

Streak plate method

simplest most common used method for isolating, spreads out cells to separate- obtain single cells so individual colonies can form

Dissolved salts, sugars make water unavailable to the cell: if

solute concentrations is higher outside of the cell , water diffuses out (osmosis)

Phase of prolonged decline

some fraction may survive, adapted to tolerate worsened conditions

Streak plate method can yield pure culture and maintained as

stock culture, frozen at -70 degrees for long term or freeze dried

Reactive oxygen species: using 02 in aerobic respiration produces harmful reactive oxygen species (ROS) as by-products which inculdes

super-oxide (02-) and hydrogen peroxide ( will react with anything free radicals-to many e-)

Major conditions that influence growth are

temperature, atmosphere, pH, water availablity

Anything else besides auto or heterotroph gets sugar from

their environment

Bacteria Survive a range of pH and have optimum : most maintain constant internal pH typically near neutral

to pump out protons if in acidic environment and bring in protons if in alkaline environment

Obligate aerobe: grows almost completely at

top of the tube

Death phase

total number of viable cells decrease, and die at a constant rate, exponential but much slower than cell growth

All microorganisms require_____ for growth

water

Halotolerant

withstand up to 10% salt concentration ( Staphylococcus)