MICROBIO EXAM 1

microbe

• single celled organism

• can only see through microscope

• very few cause disease

• not all can survive alone (make colonies/biofilms/viruses)

• can be eukaryotic (Protozoa)

cellular organisms

fungi (yeast/mold), protists (algrea/protozoa), bacteria, archaea (methanogens)

acellular organisms

viruses, viroids, virusoids, prions (mad cow)

How have we studied microorganisms?

• development of microscopes

• molecular biology

• sequencing of genomes (+their structure)

Why was studying genomes very important?

thought that by understanding the genome, we would be able to cure and create things valuable to life

Things to note about the genome

• most of the genome doesn’t code for everything, but helps to regulate other genes

• helped develop better classification of organisms

What was discussed about Celera?

• started with human genome project & people bought stocks

• they patented everything, but lawsuits followed b/c can’t patent natural things

Human Microbiome Project

12st century idea that we are not all human cells

• have microbial cells inside of us and have evolved with them

• can tell if irregularities in compositions b/c of how human’s react w/ and from

Microbiology Themes

• a basic science: understanding life processes and cellular processes

• applied science: benefits humans (medicine, ag, and industry)

Why is microbio important?

• keeps materials moving through biogeochemical cycles

• life requires microbes for survival

• oldest form of life

• lives in places unsuitable for other organisms

Types of Microbes

bacteria, archaea, eukarya

What has helped classify microbes?

16S rRNA gene sequencing

How do we know life origninated just once?

conservation of codon usage for different amino acids in all species

cyanobacteria

• produce oxygen

• blue/green filamentous

• Responsible for 1st mass extinction b/c (anaerobic to areobic)

actinomycetes

• form hyphae and stalks

• used for antibiotics

caulobacter spp.

exist as sticky sessile or mobile free swimming flagellated bacteria

myxococcus

functions like slime mold by producing fruiting bodies & organized structures

archaea

• remembles eubacteria (by looks)

• extremophiles

• gut colonization (methanogenic archaea)

Eukaryotes

• physical defining feature= nucleus (sometimes 2- giardia)

• compose plants, animals, and fungi

single celled forms of eukaryotes

yeast, protozoans, some algae

Why do we have the 3 domains?

different selective pressures caused changed (believed to be phage b/c outer celled components infiltrated cells)

Endosymbiont theory

• mitochondria were bacteria

• chloroplasts were cyanobacteria

• endosymbiosis

endosymbiosis

a biological relationship where one organism lives inside the body or cells of another organism, usually to the benefit of both

steps in the endosymbiotic hypothesis

1. ancestral eukaryotic cell lost cell wall *

2. engulfment of an endosymbiote occurred

3. genome reduction occured

4. evolution of organelles

rickettsiae

What did mitochondria descend from?

prochlorococcus

what is chloroplast descend from?

Robert Hooke

• built first compound microscope

• looked at piece of cork under microscope

• first to describe cells

• published the findings in microprahia (1665)

heat fixation

preserves morphology but not internal structures; pass slides over heat

chemical fixation

used w/ larger, more delicate organisms & preserves internal structures

dyes

two features: chromophore groups and able to bind to cells

simple stain

• 1 dye to stain cells

• determines cell size, shape, and arrangement

differential stain

divides bacteria based on staining properties (gram staining)

gram staining process

fix cells, add crystal violet, add iodine, wash with ethanol, add safranin

characteristics of gram positive

thick cell wall

characteristics of gram-negative

• outer membrane

gram positive microbes

bacillus, streptococcus, staphylococcus, clostridium, listeria

gram negative microbes

escherichia coli, pseudomonas aeruginosa, campylocater

cocci

sphere shape

staphylococci

bunches of spheres

diplococci

pairs of spheres

streptococci

chains of spheres

Tetradcocci

groups of 4 spheres

bacilli

rod shaped

types of bacilli

• single- bacillus

• pairs- diplobacilli

• chains- strptobacilli

coccobacilli

look between cocci and bacilli

vibrios

bent shape (like kidney bean/sickle cell/cause dysentery)

electron microscope

• longer sample prep process

• shows in B&W usually

• detailed

Antonie van Leeuwenhoek

• father of microbiology

• able to observe single celled organisms

• 1st to describe how heat can kill microbes

Why was spontaneous generation was important?

• if true, would mean life did not require a God to happen

• the church spent money to disprove

Key people who proved microbes arise from other microbes

• francesco redi

• lazzaro spallanzani

• edward jenner

• louis pasteur

francesco redi

italian priest that showed maggots did not spontaneously appear on decaying meat; only appeared when meat was available to flies

lazzaro spallanzani

italian priest who disproved spontaneous generation of microbes by sealing sterilized meat and seeing if microbes were produced

critiques of spallanzani’s experiment

results weren’t valid because experiment did not contain air; need air for spontaneous generation

Louis Pasteur

proposed that the transmission of microbes cause disease by boiling broth in swan necked flasks

John Tyndall

discovered that some organic matter can contain heat resistant spores because did pasteur’s experiment and had growth

Edward Jenner

• “Father of Immunology”

• Created the smallpox vaccine

• saw milk maids didn’t get small pox when had cow pox

• named for saving millions (even if they were reluctent)

variolation

• brought to europe by “lady mary wortley montagu”

• basically an attenuated virus (scraped smallpox, grinded, and injected into a body)

James Phipps

injected with smallpox vaccine as kid

Joseph Lister

used phenol to sterilize surgical equipment (antiseptic surgery 1865); 1827-1912

Ignaz Semmwlweis

• saw doctors wards has 3x mortality than midwives and found out it was b/c they had better hygiene

• observations rejected by medical community (b/c the standard was have messy hands=better doctor)

• started handwashing in hospitals (1847)

• died in asylum (1818-1865)

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Robert Koch

proposed 4 criteria that must be met in order to determine if microbes cause disease (1884)

Koch’s Postulates

1. microbe always present in diseased organism, absent in healthy

2. microbe isolated from diseased organism and grown in pure culture

3. microbe isolated must cause disease in healthy organism

4. re-isolate same microbe form now-sick individual

limitations for the postulates

• some diseases only occur in humans

• have to grow in vitro therefore viruses were eliminated

• some opportunistic

• not ethical in some situations (using humans to complete)

• immune system of species limits ability to cause disease

developments from Koch’’s work

agar, petri dish, nutrient broth and nutrient agar, methods for isolating microorganisms

Barry Marshall

used stats and evidence to show helicobacter pylori was the causative agent for stomach ulcers (gastritis) and that antibiotics could cure

strain specific pathogens

ghrelin “hunger hormone” shows that strains vary and can cause disease