Microbiology Ch 1 - Ch 3
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Robert Hooke contribution?
- 1665 observed cork cells using compound lens.
- termed word "cells" began "cell theory"
Antony Van Leeuwenhoek contribution?
- first observations of living cells taken from his own body.
- first microscope using magnifying lens
some forms of life could arise spontaneously from nonliving matter
spontaneous generation myths
- fleas from hair
- flies from fresh and rotting fruit
- locusts from green leaves
- raccoons from hollow tree trunks
- termites from rotten wood
- eels from slimy mud at the bottome of bodies of water
- mosquitoes from stagnant pond water
who proved existance of microorganisms?
what experiment did Pasteur use to prove microorganisms exist?
filtered air through cotton plug showing that filterable particles cause contamination of sterile broths.
what steps were involved in pasteur's experiment?
- trapped air escapes from open end flask (sterile broth)
- bacteria/dust from air settle in bend of flasks
- broth sterile indefinately
- flask tilted so sterile broth makes contact with contaminated bacteria/dust from air
- bacteria multiplies in broth
why was Pasteur lucky he used animal broth? how would his experiment have been different?
if he used vegetable broth or soil broth there would have been endospores present and that has a bacterial state that is very hard to kill
study of microorganisms
what techniques are utilized in microbiology?
- aseptic technique
- pure culture technique
- microscopic observation of whole organism's
who is Linnaeus and what what his contribution?
establish system of scientific nomenclature, where each organism has 2 names, the genus and species.
- genus = first word, capitalized
- species=italicized, lower case
4 domains for classifying microorganism?
- 1. bacteria
- 2. archaea
- 3. eukarya
- 4. Nucleocytoplasmic Large DNA Virus (NCLDV) NEW DOMAIN
types of bacteria
- gram negative
- gram positive
- acid fast
- cyanobacteria (blue green algae)
what type of nutrients do bacteria have?
- 1. chemotrophs- use chemical for energy
- 2. phototrophs- use light for energy
examples of bacterial diseases?
durable state of bacteria?
some form endospores
how to tell how many clusters or numbers of bacteria?
- (diplo)- 2
- (strepto)- row or line
- (staphylo)- cluster
what does diplocoques mean?
2 sphere shaped bacteria
what does streptocoques mean ?
line or row of sphere shaped bacteria
what does staphylocoques mean?
cluster of sphere shaped bacteria
what color is cyanobacteria?
description of Archaea?
- lack peptidoglycan
- live in extreme environments
- none are known to cause disease
types of archaea?
- methanogens- produce methane as waste product of respiration
- extreme halophiles- extreme salty environment
- extreme thermophiles-extreme hot, sulfurous environment
basic qualities of bacteria
- simple single cell (unicellular),
- genetic material not enclosed in nuclear membrane,
- peptidoglycan cell walls
- reproduce by binary fusion
- appear in various shapes:
- * Bacillus- rod like
- *Coccus- spherical or ovoid
- *Spiral- corkscrew or curved
qualities of fungi
- chitin cell wall
- use organic chemical for energy
which fungi are unicellular/multicellular?
- unicellular: yeast
- multicellular: mold/mushrooms
what is hyphae?
filaments that consist of masses of mycelia in molds adn mushrooms
qualaties of protozoa
- slime molds, flagellates and ciliates
- absorb/ingest organic chemical for energy
- some form durable cysts
examples of protozoa diseases?
- amoebic dysentery
qualaties of helminths?
- flatworms, roundworms, nematodes
- some are multicellular animal parasites
- microscopic stages in life cycle
examples of diseases of helminth?
- hook worm
- tape worm
qualities of algae?
- brown, red, green
- in larvae stage are swimmers
- cellulose cell walls
- uses photosynthesis for energy
disease of algae?
some poisoning associated with unicellular types
qualaties of virus?
- not cells but some have lipid membranes and require cells to reproduce
- acellular, obligate intracellular parasites
- cant cure only treat s/s
diseases of virus?
- chicken pox
what are prions?
consist of DNA, RNA, protiens
disease from prions?
- Alpners syndrome
- (infant) Scrapie
- (infant) CWD
- ALL ARE FATAL
How do microbes influence ecology?
- produce energy to ecosystem
- make nutrients avail from inorganic sources
- decomposers-liberate nutrients from no longer living sources
- form symcioses (mycorrhizal fungi assoc with plant root, found in legume nodules)
- serve as endosymbionts (chloroplast, mitochondria)
how do microbes influence industry?
- fermentation products -cheese, hyogurt, bread, pickles
- biotech- recombinant products such as insulin/vaccines
- bioremediation- microbes used at max. levels to degrade other microbes
Historians and thier contributions to microbes
- 1796- Edward Jenner - innoculated person w/ cowpox and they were then protected from small pox (immune) and coined term Vaccination
- 1860- Joseph LIster- inspired by Pasteur, used chem disinfect to prvent surgical wound infect.
- 1876- Robert Koch- proof that bateria causes anthrax and proved experimental steps to prove specific microbe causes specific disease (germ theory of disease
what is normal microbiota?
- prevent pathogens
- produce growth factors such as folic acid and vit K
- hygeine hypothesis- we are too clean so immune system out of whack.
ability for body to ward off disease
why does disease occur?
when pathogen overcomes host's resistance
conversion of units of measurement?
- 1 um = 10 ^ -6 = 10 ^ -3 mm
- 1 nm= 10 ^ -9 = 10 ^ -6 mm
- 1000 nm = 1 um
- 0.001 um = 1 nm
- images from objective lens (eye) magnifies through second lens (object)
- total magnification = objective lens X ocular lens
- lenses to distinguish two points
- shorter wavelengths of light provide greater resolution
what increases resolution?
- immersion oil d/t light not bouncing or bending
- blue light
- using electrons
what is refractive index
light bending ability of medium
why is immersion oil used for better resolution?
keep light from bending so it doesnt miss the small high magnification lens
- dark objects visible against bright background
- light is reflected off specimen adn doesnt enter objective lens
- light objects visible against dark background
- light reflected off specimen enter objective lens
what microscope we use in lab?
phase contrast microscopy
accentuates diffractrion of light that passes through specimen
- uses UV light
- fluorescent substance absorb UV light and emit visible light
- cells may be staind with fluorescent dye
- uses fluorochromes and laser
- laser illuminates each plane in specimen to produce 3 D image
what are the 2 types of highest resolution microcopy?
- electron Microscopy- uses electrons (shorter wavelength then light)
- Scanning Probe and Atomic Force Microscopy (creates image with similar resolution but does not use electrons)
what is transmission electron microscope?
- electron microscope that transmits electrons through substance
- specimen may be stain with heavy metal salt
- sliced and very thin sections
what is scanning electric microscopy?
- electron microscope where electron gun fires beam of electrons
- electrons bounce off surface of specimen
- results in 3 D image
scanning probe microscopy
- uses metal probe to scan specimen
- resolution 1/100 of atom
atomic force microscopy
- uses metal and diamond probe inserted into specimen
- 3D image
how to prepare specimen?
- thin film of soln smeared on slide
- smear is "fixed" or attached to slide (kills microbes- overheating can distort shape)
purpose of staining
definition of contrast
- results from differences in index of refraction between specimen and background
- or results with difference in index of refraction within specimen and number of visible colors in specimen
what colors are highest contrast?
black / white
what increases contrast?
- black / white color
- closing the iris diaphragm
- use of a single basic (alkaline) dye
- mordant may be used to hold stain or coat specimen
what is mordant?
- coating used to hold stain on specimen
- makes specimen appear larger
- iodine soln.
- gram stain
- acid fast
what does gram stain classify?
- a) gram positive
- b) gram negative
what can kill gram positive bacteria
penicillin and detergents
gram negative bacteria and antibiotics
gram negative bacteria more resistant to antibiotic
color changes with gram positive/ gram negative stain?
- gram positive will be stay purple color
- gram negative will stain red
how to do a gram stain?
- add alkaline crystal violet (simple stain)
- add iodine (mordant - attach to crystal violet) all cells purple
- decolorize with alcohol (crytal violet washes out gram negative cells)
- counter stain with safranin
- gram positive remains purple
- gram negative counterstains red
acid fast staining
cells that retain basic stain in presence of acid- alcohol
what happens to non acid fast cells?
loose basic stain when rinsed with alcohol and are usually counterstained with different basic stain.
what stain is used to look for pathogenic TB?
acid fast staining
- usefull to visualize capsule around bacteria
- stains background dark (doesnt stain bacteris only background)
- less distortion of cells then other special stains
- no heat used
if halo around bacteria?
bacteria is sticky if it has a halo around it and wants to stick. if no halo, then not sticky. If it is sticky then it has a sugar coating around capsule
domains of eukarya?
common myths to spontaneous generation
- Toads, snakes and mice being born of moist soil
- Flies emerging from manure
- Maggots (larvae of flies) could arise from decaying corpses.
- Snakes from horse hairs in stagnant water
- Mice from grain and cheese wrapped in a sweater
- Maggots from rotting meat
- Fleas from hair
- Mosquitoes from stagnant pond water
- Eels from slimy mud at the bottom of bodies of water
- Locusts from green leaves
- Termites from rotten wood
- Raccoons from hollow tree trunks
who was Francesco Redi and what did he contribute to microbiology?
1668 maggots did not arise spontaneously from decaying meat
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