Bio15 Lax Exam :)

inappropriate antibiotic use increases the likelihood of developing

antibiotic resistance

antibiotic resistance can arise from

- using antibiotics when they are not needed

- selecting the wrong drug for the type of infection

- prescribing incorrect dosafes

- ending treatment too early

antibiotic susceptibility test

lab test that determines how effective different antibiotics are against particular bacterial strain

- Kirby Bauer disk diffusion test (culture and sensitivity test) using Mueller Hinton agar

antibiotics diffuse at different rates depending on molecular size: standardized reference tables classify bacterial response as

sensitive (S): antibiotic will most likely work at standard doses

intermediate (i): antibiotic may work at higher doses or in combination

resistant (r): antibiotic is unlikely to be effective

symptom caused by bacteria: how to choose antibiotic

- showing effectiveness

- large zone of inhibition

- sensitive (s) on chart

why penicillin is not good for P. fluorescens

P. fluorescens is gram negative.

penicillin = beta-lactam antibiotic

G- outer membrane = penicillin cannot target peptidoglycan wall

G- produces beta-lactamase enzymes = penicillin does not work

why important to measure zone of inhibition and use standardized charts

size of zone of inhibition depends on how well it works and how well it diffuses --> molecule size

small molecule diffuse far

shows if bacterium is sensitive, resistant, or intermediate

in clinical testing what are two factors to consider beyond Kirby-Bauer test result when choosing antibiotics

- allergies

- drug interactions with other medications

disinfectants kill microorganisms on external surface are called

antiseptics

Florence Nightingale introduced routine of what on care on wounded soldiers

use of hot water and soap = drop in infection and death rates

some compounds work on some bacteria but not others --> compound is

selective

epidemic occurs when

number of individuals affected by specific infectious disease rises significantly above normally expected within population or region

study of epidemics is known as

epidemiology = identify cause of outbreak, how it spread, how to control

epidemiology: why was red colony growth the only type recorded in experiment using S. marcescens?

S. marcescens makes natural red pigment called prodigiosin when it grows

epidemiology: if we used white candy instead of red would it compromise results of simulation

not really; it'll be hard to see if red bacteria spread because the red candy color helped us visually track infection when shaking hands to contaminate... white candy = still would grow red colony because of prodigiosin in S. marcescens

factors real epidemics are hard to track

- infections spread invisibly (asymptomatic carriers)

- more transmission pathway than just shaking hands (vectors formites droplet... hard to find source of travel)

- not everyone will report everyday contact, might not remember it... hard to trace to source

- not a contained space and population (control) like the lab

why airborne epidemic more difficult to trace using same method of red candy and hand shaking

it can spread to more people at once, compared to direct contact one to one in this lab

harder to see and know who infected who, cannot "see" every exposure

lytic cycle

viral (phage) replication cycle: virus needs host cell's metabolic process for viral replication

after virus attaches to cell surface and injects DNA into host it happens

- virus infects --> replicates --> lyses cell --> causes plaques (clear zones where phage lysed bacteria)

calculate concentration of plaque forming in units/mL in original sample

PFU/mL = (plaques counted / dilution factor x volume plated)

bacteriophage (phage=virus)

virus that infects bacterial cells

lysogenic cycle of bacteriophage

viral DNA incorporated into bacterial chromosome --> form prophage (viral dna in host genome) --> bacterial cell infected, called lysogen --> grow and divide

dilution series for accurate estimation of number of viable virus particles in sample

10^-1: likely heavy lysis no lawn if too concentrated

10^-2: moderate plaques for counting

10^-3: likely fewer plaques, maybe isolated with clear rings

why important to perform plaque assays using bacteria in log phase of growth

log phase = metabolically active bacteria, dividing --> best for phage to infect replicate and lyse host cell

what is added to control plate for viral plaque

only bacterial culture to see lawn

no bacterial lawn on plate for plaque assay can mean too FEW bacteria or too MANY virus

exposing bacterial lawn with lysogenic virus (phage dna in lysogen) to UV light... affect on plaque formation

uv triggers prophage in lysogenic cells to enter lytic cycle --> cells lyse --> release new virus --> more plaque

uneven spreading of lawn... affect of plaque assay result

you need uniformal even bacterial lawn, so plaques are separated

uneven spreading results in

- uneven plaque distribution

- merged plaques

- hard to count in accuracy in PFU/mL

anthrax laced letters... strain of B. anthracis = causes anthrax in humans

strains have different mutations during cellular replication in bacteria's dna

B. anthracis distributed to different labs --> cells grew and reproduced --> replicate own DNA each division

dna replication: double helix unzips --> nucleotide create complementary pairs for sequence AT CG --> IF WRONG NUCLEOTIDE INSERTED --> mutation

Sanger method DNA sequencing

mix template DNA with nucleotides, helper proteins, and fluorescent nucleotides --> build dna strands --> fluorescent nucleotide attaches to strand, stop copy process --> incomplete copies of dna strand with varying length --> sort strands by length --> find sequence

match sequence to find where strain came from

protozoa = primitive single celled organism that resemble animals in behavior from what kindgom

protista, like algae

are EUKARYOTIC have nucleus and membrane bound organelles

- most are motile

protozoa absorb nutrients through outer membrane this is called

endocytosis = engulf external materials into cell

amoeboids move using

pseudopods

ENTAMOEBA HISTOLYTICA CAUSES

AMOEBIC DYSENTERY GI INFECTION --> invades lining of colon and forms ulcers

flagellates move using

one or more whip like flagella

FLAGELLATE GIARDIA LAMBILIA CAUSES

GIARDIASIS INTESTINAL ILLNESS --> attaches to walls of small intestine --> nutrient absorption issue --> diarrhea gas and cramps

FLAGELLATE TRICHOMONAS VAGINALIS CAUSES

TRICHOMONIASIS STI --> affect urogenital tract --> itching burning discharge or male carrier

FLAGELLATE TRYPANOSOMA BRUCEI CAUSES

AFRICAN TRYPANOSOMIASIS SLEEPING SICKNESS --> transmitted by tsetse fly causing fever joint pain swollen lymph nodes --> invade central nervous system causing confusion coma death TRAVEL IN BLOOD USING UNDULATING MEMBRANE

FLAGELLATE TRYPANOSOMA CRUZI CAUSES

CHAGAS DISEASE BY THE KISSING BUG --> bites, parasite in feces --> scratch, parasite enter bloodstream --> damage to heart esophagus colon

apicomplexans DOES NOT MOVE

non motile obligate intracellular parasite

APICOMPLEXAN PLASMODIUM CAUSES

MALARIA --> parasite transmitted by bite of infected mosquito --> plasmodium invade liver cells and RBC --> cause fevers chills sweat bursts more cells

APICAL COMPLEX PENETRATES HOST CELL --> PRODUCE CYST OR SPOROZOITE

APICOMPLEXAN TOXOPLASMA GONDII CAUSES

TOXOPLASMOSIS in pregnant women

ciliates move using

coordinated beating of cilia

CILIATE BALANTIDIUM COLO CAUSES

BALANTIDIASIS RARE INTESTINAL INFECTION --> ingest cyst in contaminated water --> large bean shaped nucleus and covered in cilia for movement --> diarrhea

plasmodium apicomplexan malaria and trypanosoma flagellate sleeping sickness are both

parasites inside RBC bumpy and in blood plasma... both depend on host body to survive

how to tell parasite vs free living

parasites: close or inside host cell, smaller than free living protozoa, have flagella or adhesive disks

free living protozoa: like amoeba and ciliates have psuedopods and bigger

why is it important to know about parasitic protozoa even in the US

- travel and import cases of parasites

- global trade, climate change increase temperature preferred by parasites, increase risk in transportation of infected organism

kingdom protista includes

protozoa (parasite and freeliving) and algae (photosynthetic)

algae vs photosynthetic bacteria

algae EUKARYOTIC and have chloroplast

single cell algae DIATOM

entire life cycle as individual cell

- shell (test made of silica or glass)

unlike calcium carbonate (clam shells) that won't let sunlight in

single cell algae CERATIUM

entire life cycle as individual cell

- shell (test made of silica or glass) with groove, flagella out of groove

filamentous algae SPIROGYRA (internal spiral structure)

made of many cells all alike, in long thread

slimey green in tide pools and stream beds

MOVE BY TWISTING BENDING STRAIGHTENING INDIVIDUAL FILAMENTS

colonial algae VOLVOX

sheets or hollow balls, some reproduce growing new small balls of cells inside larger balls

each cell of sphere has two or more flagella

pond water rotifer

why you can't tell if pathogenic organism in water with naked eye

microorganisms including pathogens (virus bacteria protozoa) are microscopic

make sure sample size is big enough to find pathogens, or zoomed in enough to see virus

fungi important

recycle dead material, return nutrient

ALL FUNGI ARE EUKARYOTES

single celled yeast also very important

fungi rhizopus with zygospores

+- mating type

fungi aspergillus with conidia covered with spores

fungi penicillium with branched conidia

fungi candida albicans with hyphae and round yeast type cell

fungi saccharomyces with budding cells

single cell, budding cells are daughter cells

no sexual reproduction, no spores, o are single cell organisms

fungi schizosaccharomyces with ascus and spores inside

fungal spores come off easily why

- rapid reproduction

- large number of spores

- dispersal mechanisms

- adaptation in diverse environments

- increase chance of reproduction

pure culture = population of cells growing in absence of any other species... how to isolate colonies of pure cultures

t streak, 2 times

good isolation: flame loop properly between sections

overlap to get enough inoculum on streaks

if bacterium has capsules (sticky surface) can cause clumping, harder to do t streak isolation

gram positive has thick layer of peptidoglycan = stain doesn't wash out

gram negative is thin = washes out

gram stain steps

- smear

- primary stain CRYSTAL VIOLET 30-45sec

- wash WATER 2-3sec

- mordant IODINE to bind crystal violet 60sec

- wash WATER 2-3sec

- wash ALCOHOL 2-5sec

- wash WATER 2-3sec

- counterstain SAFRANIN 5MINS

- wash WATER until clear

always have control because it can be dyed too long or washed too long

mutations are changes in base sequence of DNA during replication... rate increased by

mutagen (can be chemical or physical like electromagnetic radiation)

mutagen electromagnetic radiation: ionizing and nonionizing radiation

ionizing radiation: xray gamma ray damage dna rna

short wavelength high energy dangerous --> penetrate cell structure

nonionizing radiation: UV LIGHT excite electrons form dimers distort DNA strucutre in transcription

can harm human cells and cause melanoma

UV exposure increase, bacterial growth decrease

uv disrupts bacteria replication

longer exposure more killed

sunscreen reduces damage from uv

uv is not good for sterilizing syringe in plastic wrap why

uv cannot penetrate plastic so cannot work unless it is exposed surface with no chemical or physical protection

ionizing radiation is used to treat fresh fruits and veggies, why uv not as good

ionizing penetrates more with shorter wavelength and higher energy. uv has poor penetration and can only kill microbes on surface, not as reliable

obligate aerobe M. luteus

only grow when oxygen present: only respiration not fermentation

obligate anaerobe C. sporogenes

only grow when oxygen not present: only fermentation

facultative anaerobe E.coli

can grow in both: use cellular respiration when oxygen is present (energy efficient), use fermentation when oxygen is not present (not as energy efficient)

highly adaptable, requires complex regulation and multiple metabolic pathways, energy costly

microorganisms (microscopic organism like bacteria, fungi, algae) need nutrients and proper environment to grow... and use

nutrient agar

growth forms colony of identical cells

helps find PURE CULTURE = isolated and uniform in color

incubate to make sure there is no contamination

bacterial growth curve 4 stages

- lag = metabolically active but not dividing = LOW OD

- log = exponential growth (ideal for experiments) = INC OD

- stationary = cell division slows and is appx equal to death rate = stationary OD

- death = dying cells exceed number of new cells

record pattern and growth using spectrophotometer

measures amount of light absorbed

turbidity = cloudiness

emits light at specific wavelength and OPTICAL DENSITY OD determined by how much light is blocked

spectrophotometer trasmittance vs absorbance

transmittance = amount of light passes sample

absorbance = amount of light blocked

WE USE ABSORBANCE SCALE

measured on LOG SCALE

LOG GROWTH straight line on semi log graph paper

generation time population to double: double OD, find time, time in btwn