BIOL 375 Ex 1

structure, metabolism, growth, evolution

microbiome

robert hooke (1600s)

Antoni van Leeuwenhoek 1600s

1800s

Francesco Redi

Lazzaro Spallanzani

differentiation, communicate (signal transduction), motility, horizontal gene transfer

•Question of Spontaneous Generation

–The belief that life generated spontaneously from putrid & decaying materials

•Nature of Infectious Disease

–Why were some diseases contagious?  What caused them?

•Francesco Redi (1660’s) demonstrated that maggots in decaying meat were the offspring of flies

•Lazzaro Spallanzani (1760’s) demonstrated that a sealed flask of meat broth sterilized by boiling failed to spoil

Pasteur’s swan neck flask

Joseph Lister

The Semmelweis Reflex

1.Microbe must always be:

ØPresent in diseased animals

ØNever in healthy animals

2.The organism must be isolated in pure culture from the diseased animal

3.The isolated culture must cause the same disease in a healthy animal

4.The organism must be:

Ø re-isolated from the experimental animal

Øconfirmed to be the same organism as found in the original animal

liquid was sterilized in the flask, and when upright airflow could happen but no microbes, and when down all could get in, showed that SG isn’t real

•Observations:

–many diseases were contagious

–microbes seen everywhere, spoiled food, and caused fermentation

•Cleaning of wounds by Joseph Lister in the 1860’s

•Ignaz Semmelweis & hand washing, 1847

•Developed Germ Theory of Disease

–A.k.a. “Koch’s Postulates”

•Developed method for isolating pure cultures of microorganisms

–Pure culture = 1 single species present

•Discovered the causes of anthrax, TB, cholera

•Helped develop the petri plate with Richard Petri

•Hypothesized that microbes also cause disease (Germ Theory of Disease)

•Disproved Spontaneous Generation of microorganisms

•First to recognize significance of optical isomers

•Discovered microbial fermentation

•Invented Pasteurization

•Developed rabies vaccines + others

Martinus Beijerinck

Sergei Winogradsky

archaea, diverged after bacteria

used rrna to find 3 domains (rrna is well conserved)

looked for rrna in funky places, saw that some can live off non-organic stuff, unculturables

by lynn margulis

2 pathways

evidence: chloro and mito both have own DNA and ribosomes and rrna (70s instead of 80s) and binary fission all resemble bac

prok: circ dna chrom, cell membrane, cytoplasm, ribosomes, flagella, cell wall

euk: linear, plasma membrane, cytoplasm, ribosomes, endomembrane system makes lipids, flagella or cilia, cell wall

need more than one carbon source

get carbon from CO2

grow with or without o2

grow with only a small amount of O2

strep= strands

staph= clumped like grapes

zig zag guy

look like a comma

2-4 micrometers

.15 micrometers

large SA:V= small cell, small cell has a higher metabolism, faster cellular transport, faster reprod

1. gram

2. shape/size

3. growth requirements

4. physical components

maintains a positive internal turgor pressure, permeability barrier, protein anchor, E conservation, ECT occurs there, detects environmental signals, structure support for pili/flag, secretes virulence factors, communication signals, toxins, wastes, ion transport and energy storage

simple (driven by proton motive force), ABC (periplasmic binding protein and get E from ATP), group translocation

chemical modification of cargo through phospho pyruvate

glucose is phosphor as it enters the cell

a phosphate from PEP goes through some enzymes to phosphor substrate

means that glucose-6p is ready to do glycolysis

allows for certain molecules to be picked first for energy use

prok- peptidolglycan

arch- pseudopeptidolglycan

helps maintain turgor pressure, provides shape and rigidity

made up of NAG and NAM glycan chains that are cross linked by peptide crossbridges that have tetrapeptide side chains extending up

the beta (1,4) bonds is sensitive to lysozyme attack

D-aa help it avoid protease attack

bac- have waxy coat so doesnt gram stain and isnt sensitive to antibiotics, have to do acid fast stain to see (TB)

plasm- no PDG only cell mem

•Gram-Positives have a thick cell wall, up to 40 layers of PDG

–Often surrounded by S-layers, capsules, or slime layers

-has teichoic acid (extend partially) and lipoteichoic acid (extend through), no periplasm, no porins, stains purple

•Gram-Negatives have a thin cell wall with 1-3 layers of PDG

–Surrounded by an outer membrane, often encapsulated, has periplasm, has porins, no teichoic acid, outer membrane has LPS (lipopolysaccharides- •Protection from ,Dehydration, Phagocytes, Immune system. Certain antibiotics (esp. penicillin)) that contains o-specific polysaccharide (antigenic), and lipid A (a toxin), porins extend only in the outer membrane, PDG is surrounded by periplasm, stains pink

–All secreted proteins contained here until transported across outer membrane

–Also contains proteins & enzymes for nutrient processing and building cell wall

capsules and slime layer known as glycocalyx

-Capsules are thick and tightly bound to the cell

-Slime layers are thin and loosely bound to the cell

•Retention of nutrients & moisture

•Protection

•Attachment

Are often part of biofilms

biofilm- lets bac stick to stuff and gives them a safe place to live, how they colonize, can degrade things, made of poly sacc matrix

mucoid- goopy slime layer

fimbriae- attachment and pellicles (film layer at the top) (shorter and fewer)

pili- attachment (longer and more) twitching motility, and transfer of DNA through conjugation

sing circ prok genome found throughout cell, uses binding proteins to do supercoiling

not always present circular DNA separate from genome that doesn’t encode housekeeping genes and often encodes virulence factors, carries antibiotic resistance, and can destroy stuff like oil slicks

70s (50+30) target for antibiotics, rRNAs and proteins cause change in protein synth

for phosphate or sulfate when environ nut is limited

—Inclusions containing iron

—Magnetite, greigite

—Magnetosomes serve to orient the swimming of magnetotactic bacteria within a magnetic field

have monolayer membrane

met resting/ dormant cells keep cell alive in bad conditions and are resistant to dessication, heat, chem, spread thru wind, water, guts (C.diff), and are only found in G+, pathogens make spores

s=makes endospore

g=returns to veg state

reproductive, terminal, subterminal, central

flagella (swimming), gliding (needs contact with a surface, can use fimbriae), gas vesicle (regulate aquatic positions)

flagellin monomers, Proton motive force powers rotation (can be Na in marine areas)

polar (monotrichous, or amphitrichous), lophotrichus (branched), peritrichous (all over)

turn it like a corkscrew to burrow found in the periplasm, lots of G-

G- has 4 rings (L,P,MS, and C rings)

G+ has MS and C

L- LPS, P- periplasmic, MS- motor proteins, C- cytoplasmic membrane

mot proteins turn it like a rotor

CCW- propells

CW- flag flares out and causes it to tumble

there are reversible and unidirectional flagella

helps them stay in one general area

when it encounters a gradient of attractants or repellents and changes flagellar motion to move away for towards an area

—Chemotaxis (chemicals)

—Phototaxis (light)

—Aerotaxis (oxygen)

—Osmotaxis (high ionic strength)

—Hydrotaxis (water)

—Magnetotaxis (in a magnetic field)

bac sense environment with receptors that note when a concentration of something increases, if attractant, will increase runs over tumbles, w/o gradient they increase their tumbles

more on group level, increases the net movement

methyl accepting chemotaxis proteins (MCPs) detect stimuli and tell bac when to run and tumble, MCPs generally cluster to one end