Golden Age of Microbiology
made first microscope; sent descriptions of bacteria and protists to the Royal Society of London
Who is Antoni van Leeuwenhoech?
best for observing pale objects with little contrast
What are dark field microscopes?
1. capsule: organized repeating units: prevent them from being recognized
2. slime layer: loosely attached to cell; forms biofilms
What are the 2 types of glycocalyces?
light rays come from air, hit glass, then bend to get to focal point (light comes back together and crosses), they move away and the specimen gets larger
What is a light microscope?
use light as energy source and get carbon from inorganic source (CO2)
What are photoautotrophs?
researched anthrax and discovered organisms responsible for tuberculosis; created postulates to determine if microorganisms can cause disease
Who is Robert Koch?
uses polarized light to look at live specimen that would be damaged if attached to slides
What are phase microscopes?
an external structure of bacterial cells, used for locomotion, have basal body, hook and filament
What is the flagella?
magnification of objective lens and magnification of ocular lens
What is total magnification?
use light as energy source and use organic comps for carbon
What are photoheterotrophs?
Explain the importance of microorganisms.
1. play major role in recycling essential elements
2. source of nutrients and some carry out photosynthesis
3. benefit society by their production of food, drinks, antibiotics and vitamins
4. can cause disease in plants and animals
compared nucleotide sequences of rRNA subunits, proposed 3 domains
Who is Carl Woese?
thin layer of peptidoglycan with outer membrane (stains pink)
-lipopolysaccharides attached to outer membrane
- lipid A portion of LPS can cause septic shock
What is gram negative bacteria?
Explain the principles of microscopy
Wavelength of radiation
magnification
resolution
contrast
heterotrophs get electrons from same organic molecules that get the carbon
What are organotrophs?
Explain Koch's postulates.
1. microorganism has to be found in ALL cases of the disease, but absent from healthy people
2. microorganisms must be isolated, grown in a pure culture
3. put the culture into a healthy individual and it should cause the same disease
4. from the diseased organism, you must be able to re-isolate that microorganism
Explain each type of differential staining.
gram stain, acid fast stain, endosperm stain, histological stain
Explain the inclusions of cytoplasm of bacteria.
storage of nutrients, metabolic acid products, energy, building blocks, glycogen, carbon, phosphate, amino acids
Name and explain the different types of special stains
negative (Capsule) stain- look for capsule using negative stain bc dye and capsule are negative
flagellar stain
pressure exerted on semipermeable membrane by solution with solutes that CANNOT freely pass membrane
What is osmotic pressure?
Explain the issues with Koch's postulates.
1. some organisms cannot be grown in pure cultures
2. using humans for postulates in unethical
3. genetic and molecular evidence can overcome these limits
Explain the 6 types of general culture media.
defined media, complex media, selective media, differential media, anaerobic media, transport media
Explain archaea membrane, archaea cell wall, and cytoplasm of archaea.
Membrane- composed of unique lipids, lipids connected to each other through isoprene units, made of either linkages to glycerol (able to tolerate harsher environments)
Cell wall- lack peptidoglycan, most common is s layer
cytoplasm- 70s ribosomes, have circular DNA, genetic code is more similar to eukaryotes, 5.8s rRNA
look at serum (liquid portion of blood), look for agglutination of antibodies and microbes when mix serum and antibodies
What are serological tests?
Explain the two ways to culture prokaryotic microorganisms.
1. culture in liquid, broth media
2. solid medium that has addition of agar