Microbiology lecture - Carol Lauzon PDF

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Carol Lauzon...

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Microorganisms

● We are coated with more microbial organism on our human body than we have human cells ● Humans are more microbial and bacterial than we are human ● Only 1% of the microbes is known/described ○ Most microbes are in a state of starvation ○ Are alive but nonculturable (not able to be grown) ■ VBCS/VNCS ○ Most microbe organism is positive towards us ○ They like to work in communities ● Microorganism exist as multicellular organisms (Pure Culture)

● Microbial World ○ Living organisms - (can replicate on their own) ■ Bacteria ● Prokaryote (unicellular)

○ Pro (prefix) = Primitive ○ Nucleoid like/ no nucleus bound by a nuclear membrane ○ Lack mitochondria ○ Only bacteria ● Archaea - (Bacteria) ○ Prokaryote (unicellular) ○ Primitive “Extremes” ● Eubacteria - (Bacteria) ○ Prokaryote (unicellular) ○ More modern than archaea ○ Cell wall composition ■ Gram + ■ Gram ● Aerobes ○ Must need oxygen ● Anaerobes ○ Cannot have oxygen bc it’s toxic to

them ■ Eukarya ● Eukaryote ○ EU (prefix) = True ■ Nuclear membrane around nucleus ■ Possess mitochondria ■ Bacteria origin ○ Algae (unicellular or multicellular)/ Protozoa (Unicellular) ■ Protists ○ Fungi (Unicellular or Multicellular) ○ Helminths (Multicellular parasites) ○ Nonliving infectious agents - (cannot reproduce on their own) (needs a host) ■ Viruses ■ Viroids ■ Prions ■ Virions ■ Virinos

● “One microbe’s trash is another microbe’s treasure” ○ Heterotrophs -> CO2 -> Autotrophs -> preformed organic carbon ■ (Cycle) ■ Heterotroph waste feeds autotrophs, while autotroph waste feed heterotroph

● Nutritional Classification ○ Based on how a bacterium derives energy and its preferred source of carbon ○ Photo and Chemo (Prefixes) = Photosynthesis (photon energy) and typical metabolic processes ○ Photoautotroph ■ Photosynthesis (photon energy) and typical metabolic processes ● Source of carbon is CO2 ○ Photoheterotrophs ■ Photosynthesis (photon energy) and typical metabolic processes ■ Source of carbon is Pre-formed organic carbon

● Carbs ● Proteins ● Lipids ○ Chemoautotrophs ■ Derive energy through typical metabolism ● Ex. Glycolysis ■ Preferred source of carbon is CO2 ○ Chemoheterotrophs ■ Derive energy through typical metabolism ■ Source of carbon is Pre-formed organic carbon ● Carbs ● Proteins ● Lipids ○ Auto and Hetero - Prefer carbon dioxide and preformed organic carbon dioxide and preformed organic carbon respectively

● Bacteria - plural

● Bacterium - Singular

● Prokaryotic Cell Structure -

○

Flagellum(Singular)/Flagella(Plural) ■ Most efficient motor ■ Tail moves the bacteria ● Function: Helps bacteria with motility ■ Protein called flagellin ● - inogen means protein ■ Fuel used is ATP ● More motors = more ATP needed ● Starving them from ATP cause them to not function ■ Structure of flagellum ● Motor connects to the cytoplasm -> Cell membrane -> cell wall ● 1.) Basal Apparatus ○ Motor

○ Over 40 proteins in the motor ● 2.) Hook ● 3.) Filament ■ Identification ● Gram + ● Gram ○ Motile ● Monotrichous ○ Mono ■ One ○ Trichous ■ Hair ● Lophotrichous ○ Lopho■ Tuft or bundle ○ Bundles at one or both ends ● Amphitrichous -

○ Single flagellum at each hole of the bacterium ● Peritrichous ○ Peri ■ Perimeter ■ Movement ● 1.) Run(s) ○ Straight line movement ● 2.) Tumble ○ Change in direction ○ Can not do right hand turns ○ Must flip ● 3.) Twiddle ○ Idle (nowhere to go) ● Sensory domain (receptor) tells the signalling domain (receptor) which way the flagellum to move ● Chemotaxis ○ Movement towards chemicals

○ Relay message to the flagellum to move in a CCW or a CW positions ● Hook and filament works in opposite directions for a run ○ Filament turning in one direction and the hook turning in the other direction makes it move in a straight line ○ Filament and hook turning in the same direction make it tumble ■ CCW ● Counter clockwise ■ CW ● Clockwise ● Fimbriae - (Dense) ○ hair like structure ○ Are used for attachment ■ Can attach to each other ● Pilus(singular)/ Pili (plural) - (Hollow) ○ Sex pilus

○ Transfer DNA with other microbes

● Capsule ■ Adherence ● Help it stick to surfaces ■ Protection ● Protect it from losing water, heat, and viral invasion ● No receptors = nowhere for the viruses to attach to ■ **Evade immune responses** ■ Food reserve ● Not good at storing food ○ Carbohydrate (CH2O) coating for a microbe

● Streptococcus Pyogenes ○ Flesh eating bacteria

● Biofilm ○ If patient has a catheter biofilms can occur ■ Antibiotics won't work ○ Steps of biofilm formation: ■ 1) Bacterium attaches to a surface (Conditioning film (Food)) using fimbriae ■ 2) Start to attach to each other ■ 3) Bacteria start producing capsule material ((EPS) Extra Polysaccharide) ■ 4) Production of a glycocalyx

● Cell Wall ○ Christian gram ■ Gram + ● After stain is purple ■ Gram ● After stain is red or pink

○ Peptidoglycan (PG) ■ NAG -NAM -NAG -NAM ● NAG ○ N-acetylglucosamine ● NAM ○ N-acetylmuramic acid ● Penta peptide chains ● Teichoic acid ○ When bound to (Under) cell membrane it is called lipoteichoic acid ■ G+ ●

80%PG

■ G● 4% PG

○ Lipopolysaccharide (LPS) ■ Recognized whether it is a good or bad bacterium

● Alert your body whether that should or should not be there ■ If LPS is detached, LPS can cause inflammation ● When LipidA is detached it is toxic ● Lipid A is associated with Gram -

○ Mycolic acid - (acid fast bacteria infection)(AFBs) ■ When a gram stain is done, it does not stain due to its waxy nature

○ Morphology ■ Colonial morphology ● One cell that produces more cells ○ Reaches a mass that is visible to the naked eye ■ Cellular morphology ● Rod, coccus

○ Cell Membrane ■ Phospholipid bilayer ● Head is hydrophilic ● Tail is hydrophobic ■ Selectively permeable membrane ■ Site for ATP synthesis ■ Bacterium is 80% water ● Has transmembrane channels (PORINS) that allow molecules to come in

○ Cytoplasm ■ Made up of primarily water and solutes (salt) ■ Where metabolic pathways take place ■ Home of bacterial organelles

■ Nucleoid - (no nuclear membrane) ● Like a nucleus ● Is full of DNA ● Brain of the cell

■ Plasmid ● Made up of DNA ● We can use enzymes to open up a plasmid to insert the gene we want and then put it back into a bacterium ● Degrade oil

■ Magnetosomes -

● Bacteria that possess magnetosomes move on magnetic field toward organic compounds

■ Vacuoles ● Light color = Storage for organic compounds/gas ○ Uses gas to float to the surface of water to obtain UV light ○ Carbon ○ Glycogen ○ PHBs (Polyhydroxybutyrate) ■ Sugar polymer ■ Used to create recyclable plastics ● Dark color = contain inorganic compounds ○ Iron, magnesium

■ Spores ● Are resistant to heat, desiccation, chemicals, and radiation ● 1) calcium

● 2) dipicolinic acid ● 3) glycerol

■ Bacterial ribosomes ● Involved in making proteins (protein synthesis) ● Small size ● Large subunit ● Small subunit ● Eukaryotes ○ Ribosomes larger ● Prokaryote ○ Ribosomes smaller (less side effects when taking antibiotics) ● Binary Fission - (Growth) (Bi = 2/ Fission = split) ○ Growth and reproduction in numbers ○ Prokaryotic cells -> DNA is copied -> cell begins to divide -> Two identical Haploid cells (Clonal)

■ Considered asexual reproduction ○ Lag phase -> Log, or exponential growth phase -> Stationary phase -> Death or logarithmic decline phase

● Bacterial Morphology ○ Rods ○ Streptococci ○ Staphylococci ○ Diplocci ○ Spirillum/a ○ Vibrio

● Generation time ○ Is the time it takes for a population of bacteria to double in number ■ For common bacteria, the generation time is about 20-60 min ■ For common pathogens in the body, the generation time is 5-10 hours ○ The relationship between the number of bacteria in a population at a given time

(Nt), the original number of bacterial cells in the population (No), and the number of divisions those bacteria have undergone during that time ○ Equation: Nt = No X 2^n ■ For example ● Escherichia coli, under optimum conditions, has a generation time of 20 minutes. If one started with only 10 E. coli (No = 10) and allowed them to grow for 12 hours (n = 36; with a generation time of 20 minutes they would divide 3 times in one hour and 36 times in 12 hours), then plugging the numbers in the formula, thenumber of bacteria after 12 hours (Nt) would be 10 X 236 = Nt = 687,194,767,360 E. coli

● To make a cell ○ 2 things required ■ Parts, pieces to make the cell ■ Energy to make the cells

● Metabolism ○ Sum of all chemical reactions in a cell ○ Food ■ Tears, blood, sweat, flesh, muscle, etc. ■ Food types - Media (plural)/ Medium (singular) ● Nutrient media ○ Defined medium ■ Know all the ingredients and their amounts ● Example - TSB ( like a recipe) ○ Complex medium ■ Dont know the exact constituents and their amounts ● Example - BHI (Brain heart infusion)

○ Minimal medium ■ Least amount of nutrients to sustain life ● Example - very little sugar ○ Reduced medium -

■ Example - Sodium thioglycollate (reducing compound) ● Atmospheric requirements ○ Anerobes ■ Oxygen is toxic ○ Microaerophiles ■ Can tolerate small amounts of oxygen ○ Aerobes ■ Need oxygen ■ Strict obligate aerobes ● Has to be in an environment where there is no oxygen or they die ■ Aerotolerant aerobes ● Can be exposed to oxygen for a short time ■ Facultative anaerobes ● The most flexible in their atmosphere ● Can live in the presence or absence of

oxygen

● Growth requirement optima ○

Optimal conditions for microbe to grow

○ pH ■ Acidophiles ● Lemon juice ● Battery in a car ■ Neutrophils ● Baking soda ● Pool area ■ Alkaliphiles ○ Temp ■ Psycrophile ● Cold temp (0-15^C) ■ Mesophile ● Middle temp (15-45^C)

■ Thermophile ● Great than 45^C temp ○ Osmophiles ■ Two categories: ● Halophiles ○ Halogen ■ Salt ● Osmophiles ○ Sugar ■ Osmostic pressure ● Entry mechanisms ○ Diffusion (passive) ■ Movement from high concentration to a low concentration ○ Osmosis ■ Diffusion with water ● Movement of water

○ Faciliated diffusion ■ Using protein channels to allow molecules that have a hard time crossing the lipid bilayer to pass ● Transmembrane proteins - porin ○ Active transport ■ ○ Group translocation (PTS) ■ Only prokaryotes have this (Bacteria) ■ Phosphoenol pyruvate ● ■ Phosphotransferase system ■ HPR - (heat shock proteins) ●...