UNM BIOL351 (General Microbiology 1) exam 1

Major cause of death for humans until about 100 years ago

diseases caused by microorganisms

Infant mortality 100 years ago

about 30%

global estimate of microbe cells

5*10^30

Microbiology definition

study of entities too small to be seen with unaided human eye (

groups of microorganisms: prokaryotes

bacteria and archaea

groups of microorganisms: eukaryotes

protozoa, helminths, and fungi

non-cellular group of microorganisms

viruses

Viruses

- Not independently living cellular organisms

- much smaller than cells - DNA or RNA wrapped in protein

- depend on host cell's machinery to multiply and disperse

Prokaryotes

- "pre-nucleus"

- lack organelles: small, double membrane-bound structures

- 10-100x smaller than eukaryotic cells

- ALL are single cells

Eukaryotes

- "True-nucleus"

- cells with a nucleus (organelles)

_ SOME are single cells

Carolus Linnaeus (1758)

Developed a new way to categorize plants and animals

Ernst Haeckel (1866)

Wrote about the morphology of organisms, proposing 4 kingdoms; Monera, Protists, Plants, and Animals

Robert Whittaker (1969)

Proposed adding a fifth kingdom - fungi - to the tree of life

Problems with the five kingdoms

1. relationships among microbes, both prokaryote and eukaryote were speculative

2. No criteria to relate organisms between "kingdoms"

3. Implicit timeline remained - "prokaryotes", "protists", "primitive"

4. Supposition that the eukaryotic nucleus was derived from a "prokaryote" progenitor turned out to be fundamentally incorrect

Carl Woese (1978)

developed the 3 domains based on sequences of nucleotides in a ribosomal RNA gene

The three domains

Bacteria, Archaea, Eukarya

Eukarya

Animals, plants, fungi, protists, algae...

Bacteria

- prokaryotes

- singe-celled

- divide via binary fission

- derive nutrition from organic or inorganic chemicals, or photosynthesis

- Free-living or symbiotic/pathogenic/parasitic

Archaea

- prokaryotes

- lack peptidoglycan cell walls

- gained notoriety for living in extreme environments, but just as many are found in the usual places

- free-living or symbiotic, no known human pathogens

- includes: methanogens, nitrifiers, organotrophs, extreme halophiles, extreme thermophiles

Major types of organisms referred to as microorganisms

Bacteria, archaea, fungi, protozoa, algae, viruses, multicellular animal parasites

fungi

- eukaryotes

- chitin cell walls

- yeasts are unicellular

- molds and mushrooms are multicellular

- free-living and parasitic

protozoa

- eukaryotes

- absorb or ingest organic chemicals

- may be motile via pseudopods, cilia, or flagella

- free-living or parasitic (derive nutrients from a living host)

algae

- eukaryotes

- cellulose in cell walls

- found in freshwater, saltwater, and soil

- use photosynthesis for energy

- produce oxygen and carbohydrates

multicellular animal parasites

- eukaryotes

- multicellular animals

- not strictly microorganisms

- helminths - parasitic flatworms and roundworms

- some microscopic stages in their life cycles

- not microbes but included in the study of microbiology due to similarity to bacterial diseases

- transmission

- human body response (immune system)

Viruses

- acellular

- consist of DNA or RNA core

- core is surrounded by a protein coat

- coat may be enclosed in a lipid envelope

- are replicated only when they are in a living host cell

- inert outside living hosts

Effects of microbes on humans

- spoilage

- disease

- fermentation

- decomposition

Robert Hooke (1665)

- Micrographia

- insects

- molds

- coined the term cell

- walls in cork

Antonie van Leeuwenhoek (1676)

- dutch fabric merchant

- considered father of microbiology, despite it being a side interest of his

- described bacteria

- made much better microscope lenses (light microscopes)

- very secretive about lenses

- possibly knew Johannes Vermeer

Antonie van Leeuwenhoek cont.

- saw much smaller things

- "animalicules"

Before 1600 AD

- no human knowledges of microbes

- Preservation of food - fermenation

- control of diseases - restrict movement of sick

- religious and cultural practices - types of food and natural preservatives

- agricultural practices - cyanobacteria added to fields to increase yield

Spontaneous generation

- hypothesis that life arises from nonliving matter - "vital force" necessary for life

- Extension of early philosophers

- enticing because microbes are invisible to naked eye

- also used for larger organisms, like insects

Crazy former biogenesis theories

- recipe for flies

- "Goose trees"

Francesco Redi (1668)

- rotting meat experiment, showed that maggots only developing in meat with the addition of eggs

- ended debate for MACRO organisms

- consistent with biogenesis - hypothesis that life can only arise from preexisting life

John Needham (1745)

- boiled chicken broth and put into covered flask. microbes grew - supported spontaneous generation

Lazzaro Spallanzani (1765)

- repeated Needham's experiments, removed air (source of contamination). No microbes grew, supporting biogenesis

Louis Pasteur (1861)

"boiled chicken broth, and put into long, s-shaped flasks. Microbes only grew when contamination could reach the broth. STRONGLY supported biogenesis

Louis Pasteur contributions

- yeast responsible for fermentation in alcohol

- Contamination in fermentation (bacteria) - heat it up to kill the bad microbes - pasteurization

Agostino Bassi (1835)

- amateur microscopist

- proved another silkworm disease was caused by a fungus

Louis Pasteur (1865)

- more problems for silkworm industry

- pasteur figures out its a fungus

- new hygiene rules implemented

Louis Pasteur (1857)

- Germ theory of disease 1857

- first to suggest it

- vaccine for anthrax (bacterium) and rabies (virus)

germ theory of disease

microorganisms are the causative agent for most diseases

Sterile

Free of all microorganisms

John Tyndall (1877)

found that microbes in the dust and air have high heat resistance

Ferdinand Cohn (1876)

discovered and described bacterial endospores

Ignaz Semmelweis (1840)

showed women became infected after examinations by doctors working in autopsy rooms. advocates hand washing to prevent disease transmission

Joseph Lister (1879)

First to utilize hand washing and misting operating rooms with antiseptic chemicals. Techniques would become foundation of modern microbial control. Listerine named after him - eucalyptol, menthol, thymol. and methyl salicylate

Robert Koch (1876)

first to link a specific microorganism with a specific disease (anthrax). Bacillus anthracis found in blood, cultured out on nutrients, injected back into healthy animals. Established a series of proofs that verified germ theory of disease

Koch's postulates

1. specific microorganisms should be present in all cases of the disease, but not in healthy animals.

2. The specific microorganisms should be isolated from diseased animal and grown in pure culture.

3. The freshly isolated microorganism when inoculated into a healthy non-immune laboratory animal should cause the same disease

4. The microorganism should be re-isolated in pure culture from the experimental infection

Koch Laboratory

- early work all in liquid media

- growing microbes on solid media (potato slices)

Fanny Hesse

- wife of Walter Hesse (lab member)

- recommended use of agar to culture bacteria

Koch (1881)

Grew the causative agent of tuberculosis (mycobacterium tuberculosis)

Richard Petri

made dish that made solid media easier to use and keep uncontaminated

Variolation

- early form of vaccination, powdered smallpox scabs, rubbed into scratches, had 1-2% mortality (still had scarring)

- china, India, possibly as far as sudan (1100s)

- spread to Europe in 1700s

- used in Americas at least by 1706

- technique brought by Onesimus (west African slave)

- continental army used technique in 1776 on orders by George washington

Edward Jenner (1796)

- vaccination

- milkmaids contracted cowpox, but not smallpox (much milder disease)

- collected cowpox blisters and infected people with them

- Vacca - latin meaning cow

Louis Pasteur (1876)

- vaccination

- wipe out a whole flock in days

- attenuated (aged) cultures of pathogen were used to create vaccine

Chemotherapy

synthetic drugs or antibiotics

antibiotics

chemicals produced by bacteria and fungi that inhibit or kill other microbes

Quinine

- alkaloid

- from cinchona trees

- used as medicine by Quechua people of current day Peru, Bolivia, Ecuador

- 1500s or 1600s people began using it to treat/prevent malaria

- tonic water + gin and tonic

Paul Ehrlich (1912)

- syphilis - Treponema pallidum - new world disease

- salvarsan - synthetic arsenic drug

- first for bacterial disease

- nausea, vomiting, deafness, liver damage

Alexander Fleming (1928)

- penicillium fungus makes compound that kills staphylococcus aureus

Howard Florey and Ernst Chain

- purify penicillin

- 1940 it is tested and mass produced

Martinus Beijerinck

- 1888 enrichment or selective media

- goal: isolate microbes capable of nitrogen fixation

- 1888 enrichment or selective media approach

- made media with no nitrogenous compounds

- if anything grew they had to make their own N (called enrichment culture)

- 1888 enrichment or selective media results

- isolated bacteria, green algae, others

- symbiont: Rhizobium - nitrogen fixing, plant associate)

Martinus Beijerinck (1898)

recognized that viruses are infectious agents smaller than bacteria

Sergei Winogradsky

- soil and water microbes 1887-1891

- specific bacteria are linked to specific biogeochemical transformations

- N cycle, S cycle

Sergei Winogradsky cont.

- proposed and demonstrated the concepts of chemolithotrophy, and oxidation of inorganic compounds to yield energy

- autotrophy: obtaining carbon from CO2 gas

Carl Woese

- studied genetics of microbes

- tree of life

- discovered archaea: looked like bacteria, but are not bacteria

- proposed new taxonomy system

- 3 domains: Bacteria, Archaea, and Eukarya

Ribomsomes

site of protein synthesis

Ribosomes

- ubiquitous in living organisms

- critical for reading RNA transcripts and creating amino acid chains for proteins

- composed of: small ribosomal proteins + ribosomal RNA

- woese used the small subunit rRNA: 16S rRNA gene sequences

- molecular phylogeny

Coccus

spherical or ovoid

Bacillus

rod-shaped, cylindrical

coccobacillus

short rod

vibrioid

curved rod

spirillum

spiral

spirochete

long, loose helical spiral

unusual shapes (prokaryotes)

stalked, filamentous, star-shaped, rectangular

diplococci, diplobacilli

pairs of bacteria

staphylococci

clusters of bacteria

streptococci, streptobacilli

chains of bacteria

tetrads

groups of 4 bacteria

sarcina

cube-like groups of 8 bacteria

prosthecate or appendaged bacteria

-appendages

- extensions of the cellular membrane

- contain cytoplasm

- different than pilli and flagella

prosthecate or appendaged bacteria stages

prosthecate or appendaged bacteria life cycle

Cytoskeletal proteins (prokaryotes)

FtsZ (tubulin homologue), MreB (actin homologue), CreS, crescentin (Intermediate filament protein homologue)

FtsZ

- tubulin homologue

- contractile ring that divides cell

- nearly all bacteria and archaea

MreB

- actin homologue

- elongation of cell

- motility, cell-polarity

CreS (crescentin)

- intermediate filament protein homologue

- polymerizes along the inner curve

Microbial cytoskeletal protein examples and diagram

Microbial division example (appendaged bacteria)

units microorganisms are measured in

micrometers (μm, = 10^-3mm = 10^-6m), nanometer (nm = 10^-6mm = 10^-9m)

size range for eukaryotic cells

diameter: 10μm to >200μm

size range for prokaryotes

- diameter: 0.2μm to > 700μm

- length: up to 700 μm

- most cultured rod-shaped bacteria are 0.5μm - 4μm wide and

Unaided eye microscopy range

> 200μm

light microscope range

10mm - 200nm

scanning electron microscope

1mm - 10nm

transmission electron microscope range

100μm - 10pm (picometer = 10^-12m)

atomic force microscope range

10nm - 0.1nm

red blood cell size

5μm - 8μm