lecture 1

microbiology

study of organisms and acellular entities too small to be clearly seen by the unaided eye

highly differentiated cells and distinct tissues

what do microorganisms lack?

can cause disease in plants and animals

why do we study microbiology

fungi, protists, bacteria, archaea

cellular microorganisms

viruses, viroids, virusoids, prions

acellular microorganisms

proteins and nucleic acids

what are viruses composed of

RNA

what are viroids and virusoids composed of

proteins

what are prions composed of

prokaryotic

cells that lack a true membrane delimited nucleus (bacteria)

eukaryotic

cells that have a membrane enclosed nucleus , are more complex, and larger than prokaryotic cells (fungi)

domain bacteria

single celled, peptidoglycan walls, lack membrane bound nucleus, some live in extreme environments

By unique rRNA sequences

How are archaea distinguished from bacteria?

peptidoglycan

What do archaea lack in their cell walls that bacteria have?

Metabolic characteristics

What type of characteristics do archaea have that are considered unusual?

Extreme environments

Where do archaea typically live?

Domain Eukarya

includes protists and fungi

algae

type of protists that is photosynthetic

protozoa

type of protist that may be motile

slime molds

type of protists that have two life cycle stages

water molds

type of protists that have devastating diseases in plants

yeast

type of fungi that is unicellular

mold

type of fungi that is multicellular

bacteria and archaea

in what domains are DNA free in cytoplasm

Eukarya

domain where there is more than one chromosome

hopanoids

what do cytoplasmic membranes of bacteria contain

isoprenes

what do membranes of archaea contain

sterols

what do cytoplasmic membranes of eukarya contain

70s

ribosomes of bacteria

80s

ribosomes of eukaryotic and archaea

polysaccharides

what are cell walls of eukarya made of

viruses

smallest of all microbes, requires host to replicate, has proteins with genetic materials inside

central dogma

dna to rna to protein

transcription

step of dna to rna

translation

step of rna to proteins via ribosomes

Anthony Van Leeuwenhoek

first person to observe and describe microorganisms accurately

spontaneous generation

living organisms can develop from nonliving or decomposing matter

Francesco Redi

discredited spontaneous generation, showed maggots on decaying meat came from fly eggs

John Needham

put broth in flasks, boiled it, then sealed; broth became cloudy and contained microorganisms

Lazzaro Spallanzani

put broth in flasks, sealed, then boiled; showed no growth of microorganisms

Louis Pasteur

created flasks with long, curved necks, boiled the solutions, and left flasks exposed to air; saw no growth of microorganisms

John Tyndall

demonstrated that dust carries microorganisms

showed that if dust was absent, nutrient broths remained sterile, even if directly exposed to air

also provided evidence for the existence of exceptionally heat-resistant forms of bacteria

Ferdinand Cohn

discovered and described heat-resistant endospores

Agostini Bassi

showed that a disease of silkworms was caused by a fungus

MJ Berkeley

demonstrated that the great Potato Blight of Ireland was caused by water mold

Heinrich de Bary

shows that smut and rust fungi caused cereal crop diseases

Ignaz Phillip Semmelweiss

trying to stop childbed fever, though hand washing reduces risk of infectious diseases

Joseph Lister

discovered how antiseptics prevented infection

William Stewart Halsted

tried to prevent microbes from being spread in first place, one of first surgeons to use rubber gloves

Robert Koch

established the relationship between Bacillus, anthracis, and anthrax

The first of Koch's postulates

organism must be isolated from every patient with the disease and its distribution in the body must correspond to that of the lesions observed

Second of Koch's postulates

organism must be isolated and cultured outside of body in pure culture

Third of Koch's Postulates

pure organism must cause the disease in healthy, susceptible animals

Fourth of Koch's Postulates

organisms must be recovered from the inoculated animal

fifth Koch's Postulate

antibody to the organism should be detected in patients serum

Challenge with Koch's second postulate

some microorganisms cannot be grown in pure culture

Challenge with Koch's first postulate

sometimes microorganisms may be present in healthy host without causing disease

genomic techniques

how can uncultivable microorganisms be studied

Charles Chamberland

Bacterial filter that removed bacteria and larger microbes; this led to the discovery of viruses as disease-causing agent

Pasteur and Roux

discovered that incubation of cultures for long intervals between transfers caused pathogens to lose their ability to cause disease (attenuation), led to development of vaccines

immunology

study of host defenses

Edward Jenner

Discovered the small pox vaccine.

medical/oral microbiology

diseased of humans and animals

public health microbiology

control and spread of communicable diseases

mutualism

A relationship between two species in which both species benefit

commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

nosocomial infection

hospital acquired infections