Lab manual topics

Gram positive coccus isolates

Enterococcus or staphylococcus

Lactose positive isolates

Klebsialla or enterobacter

Lactose negative isolates

Pseudomonas or proteus

Narrow spectrum antiobiotics

Inhibit or kill only limited types of microorganisms

Broad spectrum antibiotics

Inhibit or kills a wide range of microorganisms

Kirby Bauer disc diffusion test

Can determine an organisms antibiotic susceptibility

Indicator organisms

Their presence indicates that fecal pollution is present

Coliforms

Gram negative rods that ferment lactose with the production of acid and gas

MPN test

Monitors presence and number of coliforms

Fecal Microbiota

Most common source of bacteria causing uti’s

Quorum sensing

How bacteria talk to each other

Autoinducer

A fischeri-produced extracellular signal

Bacteriophage

Viruses that infect bacteria

Lytic cycle

Process of infection leaving to lysis of the host cell

Plaque

The result of a phage particle infecting a cell

Lysogenic Cycle

A phage resides silently in the host integrating into the genome

Prophage

Integrated viral DNA

Lysogen

A host cell that carries a prophage

Temperate phage

Bacteriophage that have the option of entering the lysogenic cycle

Virulent phage

Bacteriophage that always lyse their host

Streptococcus pyogenes

Causes strep throat

Conjugation

DNA is transferred by cell to cell contact via a sex pious

Transduction

Bacterial dna is carried in a phage

Transformation

Naked dna is taken up directly from the environment

Competent

The state bacteria needs to be in in order to take up naked dna from the environment

Prototroph

A wild type strain of an organism

Auxotroph

A mutant that lacks the ability to synthesize an essential nutrient

Growth yield

The total amount of biomass that is produced from a given amount of growth substrate

Energy yield

The total amount of energy the organism extracts from its growth substrate

Proton motive force

Electrochemical membrane potential

ATP

High energy phosphate bonds found in metabolites

ATP synthase

Uses the energy released by the passage of protons back into the cell

Respiration

High energy electrons obtained from the oxidation of organic compounds are transferred through a series of membrane associated carrier molecules

Substrate level phosphorylation

The energy is released by breaking the chemical bonds of high energy metabolic intermediates is transferred directly to the phosphorylation of ADP creating ATP

Anaerobic respiration

Bacteria can respire in the absence of oxygen

Nitrogen fixation

Nitrogen gas is converted into ammonia which then can be assimilated into organic compounds

Geosmins

Chemicals that give soil it’s characteristic “earthy odor”

Endospore

A metabolically inactive resting stage able to withstand high temperatures, acidity, drying, and irradiation

Sporulation

Depletion of nutrients

Germination

Reverse sporulation that occurs in more favorable conditions

UV light

Destroys airborne organisms

Lag phase

When there is extensive activity within the cells but they are not multiplying

Log phase

Where the cells are happiest and rapidly multiply

Stationary phase

Rate of cell division and death are equal

Death phase

Where the cell number decreases

Sulfonamides

Selective toxic that is more harmful to bacteria than to humans

Humans and folate

Humans lack the pathway to synthesize folate

What are sulfa drugs analogs of?

PABA

Competitive Inhibition

Sulfa inhibits enzyme activity by competing with PABA for the enzymes active site

How can effects of sulfa be neutralized

Reversing the competitive inhibition

Streptococcus progenies

Causes strep throat

Hemolysis

The lysis of red blood cells

What do streptococcus pyogenes produce?

A complete hemolysis called beta-hemolysis

Dilution calculation

sample volume/sample volume + volume of diluent

Catalase

an enzyme that breaks down hydrogen peroxide into water and oxygen

Indication of a positive test on a colony covered in hydrogen peroxide

bubble formation

Catalase test

distinguishes the lactic acid bacteria from other gram positive cocci

Endospore

A metabolically inactive resting stage able to withstand high temperatures, acidity, drying, and irradiation

What is the temperature needed to sterilize bacterial media?

115 - 121 degrees Celsius

How does UV irradiation kill organisms?

By indirectly causing extensive mutations in DNA

Growth of bacteria phases

Lag-exponentional-stationary-death

Lag phase

Although there is extensive activity in cells, they are not multiplying

Exponential phase

When the cells rapidly multiply due to components required for division being synthesized

Stationary phase

Nutrients are depleted and toxic metabolic products accumulate

Death phase

When the rate of cell death exceeds division, the cell number decreases