MCBL MIDDY 1

Black Death

bacterial disease

plague

yersinia pestis

spread by fleas via rats

etiology

study of causes

robert hooke

invented compound microscope

described first microbes - fruiting structures of fungi

Antonio van leeuwenhoek

dutch amateur lens grinder

first observed single celled organisms (animalcules) - bacteria from his teeth

spontaneous generation

living creatures could arise without parents (aristotle)

francesco redi

flies around meat carcasses - meat can’t turn into flies so sealed rotting meat shouldn’t produce flies/maggots

disproved spontaneous generation for macro organisms

Lazaro spallanzani

sealed flask of meat broth sterilized by boiling failed to grow microbes for long periods

louis pasteur

swan necked flasks

disproved spontaneous generation

germ theory of disease

many diseases caused by microbes

kochs postulates

guidelines for causal relationships between disease and microorganisms

microorganism must be found in abundance in all organisms suffering from disease, but not in healthy organisms

microorganism must be isolated from diseased organisms and grown in pure culture

cultured microorganism should cause disease when introduced to a healthy organism

microorganism must be reisolated and be identical to original microorganism

kochs postulate limitations

most microbes can’t be cultured in lab

many human pathogens don’t infect other animals

some pathogens don’t cause disease in every case

don’t consider genetic/environmental factors

louis pasteur

developed first vaccine based on weakened strand of rabies

immunization is the stimulation of an immune response by inoculation with a piece of the pathogen

penicillin

first usable antibiotic (alexander fleming)

dmitri ivanovsky and martinus beijerinck

separately studied tobacco disease

infectious agent could pass through filters that block bacteria

tobacco mosaic virus

endosymbionts

microbes living symbiotically inside a larger organism

endosymbiont theory

mitochondria were bacteria

chloroplasts were cyanobacteria

either infected or eaten by other species and ended up living together

16s rRNA gene

found in all prokaryotes

large surface/volume ratios

allow for faster growth rates

rapid transport rates

enzymes are located on cell membrane

bacterial cell shapes

cocci - spheres

bacilli - rods

vibrios - bent rods

spirochetes - helical structures

irregular - everything else

cells can come in

pairs, clusters, or chains

bacterial cell

cytoplasm surrounded by cell envelope (cell membrane, wall, and outer membrane)

DNA contained in nuceloid

bacterial shape determining proteins

FtsZ - form z ring in spherical cells

MreB - form a coil inside rod shaped cells

CreS (crescentin) - forms a polymer along inner side of crescent shaped bacteria

bacterial nucleoid

single loop of double stranded DNA

isn’t separated from rest of cell

form loops of DNA called domains

RNA poly transcribes DNA —> mRNA

RNA —> protein (ribosomes)

cell division and replication

cell elongates as it grows

replicates bidirectionally

undergoes separation

cell membrane

phospholipid bilayer

have hydrophilic and hydrophobic regions

phospholipid bilayer

composed of fatty acids

hopanoids are molecules that strengthen lipid membrane

cholesterol is reinforcing agent in eukaryotes

passive and active transport

passive - follows concentration gradient

active - moves some sugars

pumps (transporters that use energy)

use atp/pmf against concentration gradient

pushes protons out of cell

bacterial cell wall

sacullus made of peptidoglycan

gram +/-

gram negative

direct cross linking

thin layer

stain pink

gram positive

peptide interbridge

thick layer

stain purple

teichoic/lipoteichoic acid

thread to reinforce wall/links wall to membrane

gram + envelope

capsule, s layer, thick wall, plasma membrane

gram - envelope

capsule, outer membrane, thin wall, thick periplasm, plasma membrane

gram - outer membrane

protection barrier

maintains permeability

asymmetric

lipopolysaccharides

porins

proteins for material transport

murein lipoproteins

link to peptidoglycan

gram stain

christian gram

crystal violet/iodine are added

alcohol is added

cell division

binary fission

elongates as grows

replicates bidirectionally to make 2 chromosomes

separation

pili and flagella

repeating protein monomers, anchored

pili more numerous, flagella longer

fimbriae and pili

thin protein filaments

twitching - individual movement

conjugation - transfer DNA between cells

flagella

whip like appendage (long protein filaments)

ring structures anchor

swimming - individual movement in liquid

swarming - multiceullar movement on solid

flagella types

monotrichous (polar) - single flagella attached to one end

lophotrichous - group attached to one/both ends

peritrichous - flagella attached on all sides

chemotaxis

movement in response to chemical gradient

attractants/nutrients - cells move up a gradient of these molecules

repellents/wastes - cells move down a gradient of these molecules

movement

runs + tumbles cause random walk

attraction concentration increases and prolongs run

net movement of bacteria towards attractants

heterotroph

use pre formed organic molecules

autotroph

fix carbon from CO2

chemotrophs

obtain energy from redox reactions

lithotrophs

use inorganic molecules as electron source

organotrophs

use organic molecules as electron source

ABC transporters

Atp Binding Casette

solute binding protein - substrate specific

ATP hydrolyzing protein - provides energy for final transport

symporter

moves two molecules against concentration gradient together

antiporter

moves molecule in opposite direction of driving ion

culture

growing microbes in culture media under controlled conditions

culture/growth media - material designed to support growth of microorganisms

pure culture

one type of organism

types of growth media

defined (all components are known), complex (nutrients/undefined substances), selective (favor one, inhibit other), differential (distinguish based on biological characteristics)

counting bacteria

direct count, viable count (small sample spread/incubated), turbidimetric (tube measured in spectophotometer), flow cytometry, other

bacterial growth curve

lag phase, exponential (log) phase, stationary phase, death phase

lag phase

after inoculation, before exp growth, don’t know how long will last

older cultures have longer lag phases

age of culture (rapidly diving culture usually doesn’t have lag phase), growth substrates, environmental changes

exponential (log) phase

cell doubling, 1-3 hours in complex media

N = N0(2)^t/td

stationary phase

cells alive but can’t be produced faster than others die

many cells stop growing

substrate limitation and waste accumulation

cells often become smaller

death phase

loss of cells due to accumulation of toxins and no new nutrients

decline in cell numbers not predictable

continuous cultures

set up in chemostat to get around bacterial growth curve

endospores

formed inside mother cell

occurs as bacteria age due to nutrient deprivation

protects against bad conditions, resistant to heat/environmental stress

biofilms

microbial cells acting together to form large organized structures

cell signal to each other (quorum sensing)

resistant to antibiotics, disinfectants, acids, immune responses, mechanical

form when nutrients are plentiful

environmental limits on mc growth

temperature

pH

osmolarity

oxygen

pressure

extremophile

organism that can grow outside of 20C —> 40C, neutral pH, .9% salt conc conditions

microorganism temp classifications

psychrophiles - 0 to 20 C

mesophiles 15 to 45 C

thermophiles 40 to 80 C

hyperthermophiles 65 to 121 C

hypotonic environment

lower solute concentration outside cell

hypertonic environment

higher solute concentration outside cell

halophiles

require high concentration of NaCl

microbes regulated pH

exchange K+ for H+ if too low

exchange Na+ for H+ if too high

pH microorganisms

neutralophiles - pH 5 to 8

acidophiles - pH 0 to 5

alkalophiles - pH 9 to 11

oxygen microorganisms

aerobes - grow in presence of O2

anaerobes - grow in absence of O2

aerotolerant anaerobes - can grow in O2, can’t use it

obligate anaerobes - inhibited by O2

micro-aerophiles - grow at low O2 levels

facultative aerobes - grow aerobically or anaerobically

microbial control

sterilization, disinfection, antisepsis, chemotherapy

control of microb growth

pasteurization - 63 C for 30 min

flash pasteurization - 72 C for 15 sec

UHT - 150 C for 3 sec

sterilization and filtration

removes microbes from liquids

disinfectants

kills all microbes

destroys eukaryotic cell

antibiotics

selectively kills microbes

minimal effect on eukaryotic cells

doesn’t work on all microbes

catabolism

breaking down for energy

anabolism

use energy to build cell components

metabolism

balance between catabolism and anabolism

energy/entropy

ability to do work/measure of disorder of a a system

electron transport system (ETS)

transfer energy associated with electrons

electrons passed through electron carriers

PMF generates ATP through ATP synth

summary - ETS enables production of ATP via PMF driving ATP synth

substrate level phosphorylation

direct transfer of phosphate from an organic molecule

oxidative phosphorylation

e- to ETS

protons —> periplasmic space

protons back inside cell via ATP synth

ATP produced

ATPase - proton channel

electron transfer and ATP generation

catabolism

organotrophy - “eating” organic molecules

lithotrophy - “eating” inorganic molecules

phototrophy - “light” absorption excites electrons

fermentation

without ETS/terminal inorganic electron acceptor

pyruvate to other products

rapid 2 ATP

fermentation vs respiration

ferm - substrate level phosphorylation

resp - oxidateive phosphorylation

no terminal electron acceptor in fermentation

resp - O2 terminal

anaerobic respiration

other electron acceptor than O2

uses ETS, PMF, ATP synth

less energy generation

only by prokaryotes

in vs out

glycolysis - glucose to pyruvate, atp, nadh (2 ATP)

pyruvate oxidation - pyruvate to acetyl coa

TCA - acetyl coa to CO2, NADH (a lot), ATP (2 ATP)

respiratory chain (34 ATP)

or

glycolysis

fermentation - pyruvate to lactate/alcohol, atp (2 ATP)