intro to microbio/microbial diversity/prokaryotic anatomy & characteristics

what are the 9 themes in microbio

1. microbes are ubiquitous

2. microbes are diverse (still learning)

3. microbes are essential for like (unknown)

   • nitrogen fixation

   • recycling

   • oxygen production

4. most bacteria live in biofilm communities

5. microbes can interact with human hosts in beneficial, neutral, or detrimental ways

   • most microbes are not harmful

6. the likelihood of developing an infection depends on 3 factors

   1. number of microbes *

   2. virulence of microbe (how well a microbe can invade immune system and cause damage) /

   3. host immunity (immunocompromised people are more likely to become ill)

7. the chain of infection can be broken (e.g., washing hands, vaccines)

8. microbes are capable of rapid change

9. we are more microbial than human (more microbial cells than human genes, 1:1 ratio)

what is the relationship between the microbiome, health, and disease?

an imbalance can lead to disease

e.g., female with UTI takes antibiotic, antibiotic clears infection, BUT good bacteria are gone

still an ongoing search

what is a microbe?

an organism or infectious particle too small to be seen without a microscope

what are the 3 groups of microbes?

1. acellular:

   • lack cellular structure

   • no cytoplasmic membranes or ribosomes

   • e.g., prions, viroids, virus or phage

2. prokaryotic:

   • simple, unicellular

   • have nucleoid

   • lack any membrane-bound organelle and a nucleus

   • contain ribosomes and cytoplasm

   • e.g., bacteria, archaea

3. eukaryotic (us):

   • large because they contain more things

   • unicellular or multiucellular

   • contain membrane-bound nucleus and multiple chromosomes, ribosomes and cytoplasm

   • have mitrochondria, lysozomes, ER, golgi apparatus (membrane bound organelles)

   • e.g., fungi, protozoa, algae

how many nanometers in a meter?

10-9

how many micrometers in a meter?

1000000

what is the naming system for microorganisms?

genus (e.g., theodor escherich):

• typically named after a person who discovered it, capitalized

• first part of name

species name (e.g., colon):

• second part of name

• where bacteria would be found in body, lower case

escherichia coli (E. coli)

who is carl linnaeus?

he formalised binomial nomenclature (modern system of naming microorganisms

where do microorganisms come from?

biogenesis: living things can only come from other living things

who is francesco reid and his maggot experiment?

believed all life comes from an egg

had 2 jars with meat inside, one covered and one uncovered

the uncovered jar had flies and they left maggots

the covered jar had no flies and no maggots

the maggots must have come from the flies

correlation does not equal causation (maggots did not come from meat just because it was spoiled)

who is louis pasteur and his swan neck flask experiment

one of the founders of microbio

many achievements: pasteurization, germ theory of disease, immunology and vaccination

lost 3 daughters to typhoid fever and blood poisoning (sepsis) (dedicated his work to them)

filled flasks that had a long neck to trap particles with broth and boiled the broth which killed any microbes that might have been in the broth

flasks were open but no microbes were present because the long neck of the flask trapped any particles that were in the air

when the flasks were laid on the side or the neck was broken off, the broth would spoil

proved that microbes in the air were responsible for any contamination

who is john snow?

father of epidemiology

discovered that the contaminated water was the cause of the cholera epidemics

what is the germ theory of disease?

scientific theory that germs can cause disease

what is the miasma theory?

a theory that disease was caused by bad air

who is robert koch?

developed a method to establish the cause of a microbial infection (koch’s postulates)

what is colistridium botulinum?

• gram positive

• endospore former

• found in the soil

• produces the most potent neurotoxin known

what is an endospore former?

An endospore is a dormant, tough, and non-reproductive structure produced by certain bacteria from the Firmicute phylum. Endospore formation is usually triggered by lack of nutrients, and usually occurs in Gram-positive bacteria

biosafety

aka biocontainment

• infectivity

• severity of disease

• transmissibility

• origin of microbe/agent

• route of exposure

levels 1-4

bsl1

well characterized

does not cause disease

minimal potential hazard

e.g., E. coli

PPE: coat, gloves

bsl2

various agents

cause mild disease

or difficult to contract via aresol in lab setting

e.g., measles salmonellae, hep. B, staphyll

PPE: coat, gloves, goggles, BSC

most flus are bsl2

bsl3

indigenous or exotic agents

may cause serious or lethal disease

e.g., tuberculosis, yellow fever, west nile virus

PPE: BSC, coat, gloves, goggles, sleeve covers, masks

bsl4

high individual risk of aerosol

transmitted lab infections

cause severe to fatal disease

NO vaccines or other treatments available

8 bsl 4 labs in US, ~60 worldwide

e.g., hemorrhagic fever virus, small pox (eradicated)

what are the basic shapes of prokaryotes?

• coccus

• rod (bacillus)

• vibrio

• spirillum

• spirochete

what is morphology?

the branch of biology that deals with the form of living organisms, and with relationships between their structures.

how does the plane of cell division determine the way cells are grouped?

• if cell divides in one plane it can group in a chain

  • e.g., streptococcus: Gram-positive, nonmotile, nonsporeforming, catalase-negative cocci that occur in pairs or chains

• if cell divides in two or more planes, it can group in a packet

• if cell divides in several planes at random, it can group in a cluster

  • e.g., staphylococcus:

what is a membrane protein?

common proteins that are part of, or interact with, biological membranes. Membrane proteins fall into several broad categories depending on their location

some can be transporters which allow desirable molecules to enter, receptors which bind to signals either inside or outside the cell and transmit info, or enzymes

what is peptidoglycan?

a substance forming the cell walls of many bacteria, consisting of glycosaminoglycan chains interlinked with short peptides.

what are the two defenses that target peptidoglycan?

• lysozyme

  • an enzyme found in tears, saliva, and other bodily fluids

  • breaks bonds in peptidoglycan

  • cell wall is destroyed

• penicillin

  • produced by the fungus penicillium

  • prevents peptidoglycan synthesis

  • kills actively growing bacteria (mostly gram +)

what are the differences between bacteria and archaea?

• archaea cell walls do not have peptidoglycan

• archaea have different lipids in cell membrane

• archaea have different shape ribosomes

• archaea are not known to cause disease

what is the bacteria that lacks a cell wall?

mycoplasma species