-
Antonie van Leeuwenhoek
Microscope builder (animalcules)
-
Lucretius
proposed disease caused by invisible living creatures
-
Aristotle
spontaneous generation
-
francesco redi
cheescloth over meet=no maggots
-
John Needham
boiled broth sealed in jars still becomes turbid
-
Lazzaro Spallanzani
- sealed flasks that where boiled did NOT become turbid
- air required for growth?
-
Louis Pasteur
- First to connect cause and effect of microbs and disease
- discovered fermentation
- disproved spontaneous generation
-
Robert Koch
- methods led to pure bacterial cultures
- Koch's postulates still used today
-
Koch's postulates
- 1)Show that the isolate is only present in diseased animals
- 2)Isolate the organism
- 3)Show that the isolated organism causes disease in healthy animals
- 4)Re-isolate the organism and show that it is the same as the original
- Limitations:
- must grow in pure culture
- slow organisms won't work
- complex nutrients or social needs won't be met
-
Fannie Hesse and Richard Petri
created Agar and Petri plate
-
Edward Jenner
Smallpox vaccine
-
Ferdinand Cohn
founder of bacteriology (described spores)
-
Sergei Winogradsky
concept of chemolithotrophy and autotrophy
-
Martinus Bejerinck
- enrichment culturing meathod
- idea behind virus
-
Alexander fleming
penicillin
-
Howard Foley
Industrial production of penicillin
-
Selman Waksman andd Albert Schatz
discovered streptomycin in soil bacteria
-
Thomas Brock
Discovered bacteria in hot springs (Thermus aquaticus) which gave us Taq polymerase
-
Carl Woese and George Fox
Discovered Archaea
-
Craig Venter and Hamilton Smith
first complete sequence of a bacterial genome
-
uses of bacteria in every day life
- Food (fermentaton, additives, preservatives)
- Diseases (treatment and identifying of new diseases)
- Energy/enviro
- biotechnology (genetically modified)
- Agriculture (nutrient cycling, husbandry)
-
Carl Linnaeus
Naming of organism into genus and species
-
Scientific naming
- Genus and Species
- Latin
- Italicized or underlined
- genus is capitalized, species is lowercase
- after first use in paper the genus is simplified into its first letter only
-
Escherichia coli
- Gram negative
- facultative anaerobe
- motile
- lives in GI tracts
- famous for being model organism & food poisoning
-
Ribosomal RNA
- Quantitative measure of relatedness/evolution of life forms
- consists of small subunit: 16S in Prok, 18S in Euk
- a structural molecule (not translated to protein)
- contains conserved and variable regions which allows for discrimination of relatedness
-
Prokaryotes vs Eukaryotes
- 1) Prokaryotes GENERALLY have no defined organelles (no nuclear membrane)
- 2) Prokaryotes are GENERALLY are smaller
-
caulobacter
fresh water appendaged/budding bacteria
model for complex prokayotic cell cycle
-
filamentous
- chloroflexus (photosynthetic, no o2 produced)
- bacteria that form thin strands that group together to form strands
-
Morphogenesis
change in shape
-
monomorphic
one shape for lifetime, observed in most pure cultures
-
pleomorphic
multiple shapes which can change during growth or due to environment (sporulation)
-
sporulation
creation of spores due to nutrient limitations
-
Arthrobacter sp.
Pleomorphic bacteria that undergoes morphogensis from rod to coccus
-
Macromolecules in Prok
- Proteins: throughout
- Nucleic acids: DNA in nucleoid; RNA in cytoplasm & ribosomes
- Polysaccharides: cell wall and granules
- Lipids: cytoplasm, cell wall, granules
-
Pourpose of Bacterial membrane
- 1) permeability barrier: prevents leakage and is gateway for transport
- 2) Protein Anchor: proteins involved in transport, bioenergetics and chemotaxis are located here
- 3) Energy conservation: PMF site
-
Phospholipid Bilayer
- Hydrophillic glycerol & phosphate backbone
- Hydrophobic fatty acid tails
- Archea actually have a Mono layer
-
Ester vs Ether bonds
- Ester linked lipids= bacteria and euk
- Ether linked lipids= Archaea (also have Isoprene chain instead of fatty acid chain)
-
Simple transport
- Driven by the energy in the proton motive force or by gradients.
- 3 mechanisms: uniporter, antiporter, and symporter
-
Group translocation
- The Phosphotransferase system (PTS)
- chemical modification of substances combines substances
- driven by high energy PEP
-
ABC system
- Periplasmic binding proteins assist in transport
- driven by ATP
- A=attaching to Periplasmic protein
- B= travel through mebrane protein
- C= use of ATP for hydrolysis protein
-
Uniporter
Single molecule transport along gradients but through specific channels
-
Antiporter
- two molecules transported through channel but in opposite directions.
- driven by PMF
-
Symporter
- Two molecules being transported through a channel in the same direction
- driven by PMF
-
Gram staining
- Christian Gram
- 1) cells stained with insoluble crystal violet
- 2) cells decolorized with alcohol (Gram + dehydrate and prevent dye from escaping resulting in purple colour)
- 3) counter stain of safranin (stains gram - bacteria purple)
-
Gram + vs Gram -
- Gram positive bacteria are susceptible to penicillin like anitibiotics
- gram positive bacteria "can" form spores to make them more resistant
- gram positive require additional vitamins or amino acids
-
Thermoplasma volcanii
- facultative anaerobe
- no cell wall (changes shape)
- HOT temperatures (55-60)
- loves acidity (0.5-4 pH)
- monotrichous flagella
-
Gram positive cell wall
- normal cytoplasmic membrane: contains proteins
- peptidoglycan layer: contains lipoteichoic acid (whole length), teichoic acid (partial length), proteins
-
Gram negative cell wall
- normal cytoplasmic membrane: contains proteins
- periplasm: contains thin peptidoglycan connected to outer membrane by lipoproteins
- Outer membrane: second lipid bylayer containing porins, proteins, and lipopolysaccharides (LPS)
-
Lipopolysaccharides (LPS)
- located in Gram negative cell wall
- Lipid A: binds to second bylayer
- Ketodeoxyoctonate (KDO): binding between Lipid and Polysacch
- Core: polysaccharides
- O specific: unique polysaccharide for each species
-
Porin
Channel for entrance and exit of hydrophillic low molec weight substances
-
periplasmic space
- almost non-existent in gram positive
- contains enzymes that help nutrient metabolism/acquisition
-
Chemolithotrophs
extensive arrays of electron transport proteins extending from periplamic space to outer membrane, used for inorganic ions
-
exoenzymes
- secreted by cell for nutrient transport
- in the periplasmic space
- ex. amylases aiding in mobilizing sugars
-
Capsule and slime layers
- made of polysaccharide matrix
- allows for attachment, resistence, and even virulence
-
cellular inclusions
- 1) Carbon storage: poly B Hydroxybutyrate
- 2) Sulfur storage: Sulfur granules in chromatium buderi
- 3) Magnetosomes: magnets that allow orientation of bacteria, often associated with O2 concentration
- 4) Gas Vessicles: allows flotation
-
Psychromonas ingrahmii
- Psychrophile (lives in sea ice, sub zero seawater)
- facultatively aerobic heterotroph
- non-motile
- lowest recorded growth temp (-12)
-
Endospores
- Gram positive bacteria in nutrient deprivation creates spores that are resistant to environmental stress.
- Few exceptions of gram neg bacteria forming spores
- controlled by complex cascade of sigma factor gene expression events
- consists of DNA- Cortex- Core wall- Spore coat- Exosprium
-
Sporulation stages
- stage 1) Assymmetric cell division: commitment to sporulation
- stage 2) Prespore is formed at one end of cell and engulfment into the main cell occurs
- stage 3) engulfment has occured and cortex formation begins
- stage 4) spore contains cortex, cell wall, and membrane
- stage 5) extra coating, Ca2+ uptake, SASPs (small acid soluble spore proteins), diplocolinic acid
- Stage 6-7) maturation and cell lysis releasing mature spore
-
Dipicolinic acid
Unique to spores which crosslinks with Ca in spore coat and makes impenetrable barrier
-
spore -> vegetative cell
- 1) activation: heating to sub-lethal temp
- 2) place in nutrients
- 3) germination: rapid RNA synthesis, protein and DNA. Breaks out of spore coat
-
-
types of flagella
- monotrichous: attached at one end
- amphitrichous: attached at both ends
- lophotrichous: tuft at one end
- peritrichous: all over cell
-
flagellum (gram negative)
3 parts: Fillament (flagellin), Hook (hook protein), and Basal Body (3 rings)
3 Rings: L ring (in LPS) - P Ring (in peptidoglycan) - MS ring (in cytoplasm with Mot protein and Fli proteins)
powered by PMF moving through Mot protein
Gram Positive only has 2 rings (no LPS)
-
Gliding motility
- Flavobacterium johnsioniae
- powered by PMF
- outer membrane contains proteins that connect to peptidoclycan layer and "walk" in one dircetion which pushes the cell in the opposite direction
-
Axial filaments
- aka Endoflagella
- usually in spirochaetes
- anchored at end of cell and rotates the whole cell
-
chemotaxis
directed random movement towards a gradient through increase or decrease of length of runs
-
Phototaxis
attraction to certain wavelength, swarming towards light source
-
Macronutrients
- CHONPS= building blocks of cell
- K, Na = membrane transport
- Ca, Mg = enzymatic function
- Fe = Cytrochromes and iron sulfer proteins
-
Redfield ratio
- 106C : 16N : 1P
- ratio of nutrients in seawater & in marine bacteria!
- caused because bacteria shape their environment around them
-
Micronutrients
Mn, Zn, Co, Mo, Ni, Cu
-
Siderophore
bind iron for transport into cell. transports Fe (III) which is not very soluble, but common.
-
Growth factors
- something a cell needs but can't create
- vitamins, AA, Purines/Pyrimidines
-
Phototroph
able to grow on minimal media. can produce required growth factors
-
auxotrophs
unable to synthesize essential nutrient(s) required in MM
-
Defined media
- everything in media is known. Only phototrophs will grow.
- same as minimal media
-
complex media
Unknown contents of media but rich enough for auxotrophs
-
selective media
- encourages growth of certain organisms and discourages others
- ALL media is selective
-
Differential media
distinguishes identity of certain microbes based on growth and appearance
-
Divisome
- responsible for cell division
- made of divisome complex which is powered by atp but the FtsZ ring which actually is responsible for the division is created using GTP
-
Peptidoglycan synthesis
- Bactoprenol: brings in Nam and Nag/precursors
- Autolysin: breaks existing glycolytic bonds for new insertion
- Penicillin proteins: transpeptidation (new poly peptides)
-
Growth pattern
- Lag phase
- exponential
- stationary
- death
-
Lag phase
- gearing up for cell division
- caused by age of culture, initial numbers, environmental changes, or synthesis of new enzymes needed.
-
exponential phase
- N = No2^n
- N=cell density at time, t
- No=initial cell density
- n=t/g
- g=generation/doubling time
n= 3.3 (log N-log No)
-
Stationary Phase
- cells alive but not growing or dying
- smaller cells in survival mode, sporulation
- caused by substrate limitation, O2 decrease, toxins. NOT due to crowding
-
cryptic growth
decrease growth rate so death is almost= to growth
-
Death phase
- decline in numbers, linear or exponential but never inverse of exponential growth
- transferring colonies to new plate shows lower than expected numbers
-
types of measurements of microbial growth
- direct count: Cells are counted under microscope (least reliable, dead counted)
- viable plate counts: counted on incubated plates (only works if you know the bacteria will grow on the media)
- turbidimetric: turbidity of culture tube is measured by spectrophotometer (doesn't work at high cell numbers)
- Indirect meathods: O2 consumption, CO2 production, ATPase, ect
-
Great plate count anomaly
- direct plate counts are 1000x larger than viable plate counts:
- caused by syntropy
- bacteria might be dead
- bacteria might be nonculturable
- might not have proper "food" in the plate (most likely)
-
Chemostat
- continuous exponential growth by having a dilution rate (flow) and growth rate matched up along with excess bacteria being removed
- used for industrial production, waste treatment, or any harvesting of cells
-
barophiles
high pressure organisms
-
optimal growth temps
- Psychrophile - 4
- mesophile - 39
- thermophile - 60 (<45)
- hyperthermophile - 88 (<80)
- hyperthermophile - 106
-
pH
- neutrophiles - 6-8
- acidophiles - below 5.5
- alkaliphiles - above 8.5
pH of all organisms internally is near neutral
-
Haloquadratum Walsbyi
- strict aerobe
- nonmotile
- 20% NaCl, salterns
- SQUARE
-
Osmophiles
- halophiles - require NaCl for growth (1-6% or 6-15%)
- extreme halophiles - require 15-30% NaCl
- Halo Tolerant - tolerate reduction in aw but not beneficial
- Osmophiles - grow in high sugar environments (yeast and fungi)
- xerophiles - grow in very dry environments
-
compatible solutes
made in cytoplasm to change aw so that it decreases and water won't leave the cell.
-
leibigs law of the minimum
biomass of organism is determined by the limiting nutrient
-
shelfords law of tolerance
at certain environmental limits a organism will not grow no matter what
-
SOD
- Super Oxide Dismutase: all O2 using organisms have this (even microaerophile)
- removes toxic oxygen species
-
catylase
present in most O2 using organism to help oxidise H2O2
|
|