BIO 208 Lab Quiz 2

___________ immune mechanisms can recognize billions of different antigenic structures and launch a directed attack against each one. Once such an attack is under way, the immune system stores a "memory" of the exposure in the form of specific memory cells.

Adaptive

microorganism which prefers anaerobic conditions but can tolerate exposure to low levels of oxygen

Aerotolerant

Examples of when Endospores form (2)

Amino acids or water is no longer available

substance that triggers an immune response (such as the production of antibodies)

Antigen

chemicals that remove pathogens from the surface of living tissues, such as the skin

Antiseptics

heat loving microbes (50-80 degrees C)

Thermophiles (hot springs)

Ampicillin is a broad/narrow spectrum drug

broad (effective for both GP and GN bacteria)

Many bacteria, especially pathogenic bacteria, have a thick polysaccharide __________ surrounding the cell

capsule

chemicals that kill organisms

cidal agents

pure culture

contains only one species or strain

___ stains allow microbiologists to detect differences between microbes or parts of the same microbes and allows us to divide bacteria into GP and GN bacteria

differential stains

the killing, or removal, of disease-producing organisms from inanimate surfaces

disinfectants

the optimum growth temperature is close to the typical temperature of the _________ in which the microbe naturally lives in

environment

Decolorizing agent in gram stain vs acid stain

ethyl alcohol acid alcohol

live in extreme environments for humans

extremophiles

Can make enough ATP to survive using using fermentation or respiration.

facultative anaerobes

the thick waxy lipids in acid fast bacteria slows down nutrients and thus slows _________ __________

growth rates

Adaptive/Innate responses are present even before birth

innate

The system of nonspecific mechanisms the body uses for protecting against pathogens.

innate immunity

Gram-negative bacteria have a cell wall with an outer membrane consisting of alcohol soluble lipids called _____________

lipopolysaccharides

Obligate aerobes

require O2 for cellular respiration; depend completely on aerobic respiration to produce ATP

bacteria not inhibited or killed by a concentration of drug that patients can tolerate

resistant bacterial strain

pour plate

sample is serially diluted diluted samples are mixed with liquid agar mixture of cells and agar are poured into sterile culture dishes allows you to find a dilution that provides well-isolated. countable colonies

the ability of an antibiotic to attack a unique component of microbial physiology that is missing or distinctly different from eukaryotic physiology

selective toxicity

Compare measured zone to value listed in standardized table to see if the bacterium is _________ if that particular antibiotic

sensitive

bacteria inhibited or killed by a concentration of drug that is low enough that patients can tolerate the drug

sensitive bacterial strain

Two types of pipettes: -_________ pipette: meant to be emptied to deliver the total volume (have graduations down to the tip) -_________ pipette: delivers the volume read on the graduations

serological measuring

a means of survival for bacteria where spores become enclosed in several protein coats that resist drying, heat, and most chemicals

sporulating (form endospores)

inhibit the growth of microorganisms but may not kill enzymes; microbes may resume growth if removed from the chemical

static agents

2 forms of highly reactive oxygen

superoxide (O2-) and hydrogen peroxide (H2O2)

catalyzes conversion of superoxide radicals to hydrogen peroxide and water

superoxide dismutase

describes the values between the minimal and maximal growth temperatures that can support growth and metabolism the lowest temperature at which the species will grow = the highest temperature at which growth is possible = the temperature at which the species grows best =

temperature growth range minimum growth temperature maximum growth temperature optimum growth temperature

the most difficult of all living things to kill

Endospores

Cellular target and Action: Nystatin

-Changes permeability of fungal cell membrane -Fungicidal

Cellular target and Action: Penicillin/Vancomycin

-Disrupts cell wall synthesis and promotes osmotic lysis -Bactericidal

Cellular target and Action: Gentamicin

-Inhibits protein synthesis -Bactericidal

Cellular target and Action: Tetracycline

-Inhibits protein synthesis -Bacteriostatic

acid fast stain procedure

1) Primary stain, Carbolfuschin dye - basic dye stains bacteria hot pink (10 minutes) 2) Decolorize the smear with Acid-Alcohol mixture, holding slide at 45 degree angle and rinsing until mixture runs clear (pink stays in layers of mycolic acid) (4 to 5 seconds) 3) Counter stain, methylene blue dye - Binds to all bacteria but hot pink will mask the blue in acid fast bacteria (45 seconds)

Antibiotics are produced by (2) and affect the growth of another bacterium

bacteria and fungi

Cidal agents are influenced by (3)

1. how the chemical is used 2. the length of time the chemical is in contact with the microbe 3. the nature of the microbe

Gram stain - describe the procedure:

1. primary stain is crystal violet (a basic stain w/a positive charge), which attracts to the negatively charged bacteria. All cells will be purple (30 seconds) 2. apply mordant - iodine: combines with crystal violet (CV) to form crystal-violet-iodine complex (CV-I). This enhances color intensity and enhances binding to thick peptidoglycan layer of G+ cell walls. Still both G+ and G- are purple. (10 seconds) 3. Decolorization - ETHANOL: outer lipid layer of G- cells is extracted, color molecules are lost in G- cells. in G+ cells, peptidoglycan layer (with many cross links) will retain stain. G- are decolorized and G+ cells purple. G+ cells have no lipid layer to remove so the alcohol traps the CV-I complexes even more firmly in the peptidoglycan layers 4. Counterstain with Safranin (another basic stain): stains G- cells. G- cells are pinkish, and G+ cells are purple. (30 seconds) After each stain, rinse with water. Wait for a minute before rinsing for all steps except #3. Blot using bibulous paper

Gram negative bacteria have a cell wall that has only _______% peptidoglycan

10-15%

Pour plating: Transferring 0.1 ml into 9.9 ml of melted agar from an original undiluted sample results in a _______-fold dilution

100

E. coli take ________ minutes to divide Mycobacterium take ________ __________ to divide

20 several hours

a lymphocyte not processed by the thymus gland, and responsible for producing antibodies

B cells

Genera in the GP Phylum Firmicutes that can sporulate

Bacillus and Clostridium

Name a pathogenic species from the following genera: -Bacillus -Clostridium

Bacillus anthrax (causes anthrax) C. tetani (causes tetanus)

white blood cell containing granules that stain blue; associated with release of histamine and heparin

Basophil

an enzyme that catalyzes the reduction of hydrogen peroxide to oxygen and water

Catalase

__________- cells are different from macrophages in structure and because they take up small soluble antigens from the surroundings in addition to phagocytizing whole bacteria.

Dendritic

A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions (heat and chemical resistant)

Endospore

a white blood cell containing granules that are readily stained by eosin and release products toxic to microbes

Eosinophils

Gram Stains: S. aureus Bacillus E. coli

GP GP GN

Are acid fast bacteria gram positive or gram negative?

Gram positive but the waxy lipids prevent the gram stains from reaching the peptidoglycan layer (stain = ineffective)

Organisms that grow in extremely high temperatures (Above 80 degrees C)

Hyperthermophiles (deep sea geothermal vents)

A disk diffusion test to determine the susceptibility of a microorganism to chemotherapeutic agents

Kirby-Bauer disc diffusion assay

Why do old bacterial cultures not produce reliable gram stain results

Lost their ability to retain the primary stain (GP may appear red)

the capsule surrounds the cell wall of bacteria and covers up __________ which phagocytic cells of the host innate immune defense system recognize invading bacteria

MAMPS (microbe-associated molecular patterns)

moderate temperature loving microbes (15-45 degrees C)

Mesophiles (humans)

Aerobes that require oxygen levels from 2-10% (rather than 21%) and have a limited ability to detoxify ROS

Microaerophiles

An leukocyte that is able to migrate into tissues and transform into a macrophage or dendritic cell

Monocytes

Medically important acid fast bacteria (2)

Mycobacterium (M. tuberculosis, agent of tuberculosis, and M. leprae, agent of leprosy) Nocardia

Most abundant white blood cell., The most abundant type of white blood cell. Phagocytic and tend to self-destruct as they destroy foreign invaders, limiting their life span to a few days.

Neutrophils

cold-loving microbes (-5 to 20 degrees celsius)

Psychrophiles (polar ice or deep sea)

3 extremophiles

Psychrophiles, Thermophiles, and Hyperthermophiles

Organisms that can grow in cold temperatures (0-37 degrees C)

Psychrotrophs (refrigerators)

a group of extremely reactive peroxides and oxygen-containing radicals that may contribute to cellular damage

Reactive Oxygen Species (ROS)

the range of microbes that a given drug affects

Spectrum of activity

Differentiating step in acid fast staining

Step 2 - decolorizing

What may have went wrong if E. coli has some red and some purple cells

Step 3 of decolorizing the stain was done incorrectly (some CV and CV-I didn't wash free)

Cells created in the thymus that produce substances that attack infected cells in the body

T cells

Making a smear prep

This is done before staining. A thin film of the microorganism is spread on the surface of a microscope slide. The slide is allowed to air dry, then is specimen is heat fixed by passing the microscope slide through a burner flame.

5 patterns of growth in growth cultures -__________: cells are evenly suspended to produce a uniform cloudiness -__________: cells form a thick later at the top of the broth -__________: cells settle to the bottom to form a loose "pellet" -__________: cells remain near the surface and tend to cling to the sides of the tube -__________: cells are floating in visible, separated clumps called "flocs"

Turbid Pellicle Sediment Ring Flocculent

acid fast stain

a differential stain used to identify bacteria with high concentrations of waxy lipids (e.g. mycolic acid) that are not decolorized by acid-alcohol

Immune responses activated by a specific antigen and mediated by B cells and T cells

adaptive immunity

Quadrant Streak Plating Method

allows sequential dilution of the original microbial material over the entire surface of a fresh plate. The original sample is diluted by streaking it over successive quadrants, the number of organisms decreases. This produces single, discrete colonies (appear bigger than original colonies)

against bacterial life =

antibiotic

__________ serve as a chemotherapeutic drug unlike antiseptics or disinfectants

antibiotics (any chemical used in the treatment, relief, or prophylaxis of a disease)

Read the fluid volume of a pipette at the lowest level of the _________

meniscus

Slide of red rods and purple cocci =

mixed culture with multiple types of bacteria

Penicillin G is a broad/narrow spectrum drug

narrow (only effective for GP bacteria)

Elevated ________ or their precursors, called band cells, suggest a bacterial infection Elevated _________ suggest a viral infection. ·Increase in _________ can indicate the presence of intestinal parasites or some blood parasites

neutrophils lymphocytes eosinophils

carry out fermentation or anaerobic respiration and cannot survive in the presence of O2; lack oxygen-detoxifying enzymes

obligate anaerobes

antibiotics can be administered in what two ways

orally or by injection

To cope with potential damage caused by ROS, some cells produce ______________ enzymes

oxygen-detoxifying

Gram positive bacteria have a cell wall has thick layer of _____________

peptidoglycan (90%)

2 ways to isolate cells on solid media

pour plating and quadrant streak plating

Pour plating is more time consuming but has one major advantage over streak plating in that it can be done __________

quantitatively (determine concentration of living cells in a liquid sample)

________ ________ act as a strictly regulated port of entry that opens and closes in response to various signals.

tight junctions

Why will most simple stains not adhere to capsules

uncharged

Endospores are much more resistant than active _________ (growing) cells to the damaging effects of drying, heat, radiation, and toxic chemicals (e.g. disinfectants)

vegetative

in endospore staining, the _________ portion binds to dye while the endospore inside remains unstained

vegetative

a capsule is an important __________ __________ of pathogenic bacteria

virulence factor

trait that enhances ability to cause disease =

virulence factor

the thick waxy lipids in acid fast bacteria protect the cells from (2)

water loss (survive long in environments) host immune defense/penetration of disinfectants & antibiotics

If G+ cells lose their color and appear G- (too much pink), what likely happened?

you decolorized w/ethanol for too long

Region around a chemical saturated disc, where bacteria are unable to grow due to adverse effects of the compound in the disc

zone of inhibition