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What is microbiology?
Is the study of life forms too small to be seen with the naked eyes.
Give some examples of microorganisms.
Bacteria, fungi, virus
Name some sub--‐‑disciplines of microbiology.
Bacteriology, Virology, Mycology, Parasitology, Medical microbiology, Immunology…
What is Binomial Nomenclature?
2 parts naming of organism (Genus-Species)
What is the contribution of the following scientists? A. Anton Von Leeuwenhoekand 2. Robert Hooke
Anton Von Leeuwenhoek established the first microscope, first to describe protozoa,RBC,…Robert Hooke reported that living things were composed of little boxes or cells meaningorganism consists of many organelles
What is “spontaneous generation” theory? Who all tried to disprove this theory?Through what experiment?
Spontaneous generation theory is the hypothesis that living organisms arise from non-living matters, a “vital force” forms life.Francesco Redi, Lazzaro Spallanzani, and Louis Pasteur tried to disprove this theory.Redi’s experiment: flash (unsealed) with meat inside produce fly eggs, flash sealeddoesn’t, and flash covered with gauze produce eggs on top of gauze à experiment ofbiogenesis- the hypothesis that living organisms arise from preexisting life.Louis Pasteur demonstrated that microorganisms are present in the air.
What is chemotherapy?
Treatment with chemicals
What are antibiotics?
Chemotherapeutic agents used to treat infectious disease à produced naturally byorganisms to kill organisms
What are the three “Domains” microorganisms are classified into?
Bacteria, Archaea, and Eukarya
Distinguish between bacteria and archaea.
- Bacteria:o Prokaryoteso Have Peptidoglycan cell wall (protein + carbohydrate)o Produced by binary fission – asexuallyo For energy, use organic chemicals, inorganic chemicals, orphotosynthesis
- • Archaeao Prokaryoteso Lack peptidoglycano Live in extreme environments include: Methanogens, extreme halophiles –high salt concentration, and extreme thermophiles – high Temperature
Distinguish between prokaryotes and eukaryotes.
- • Prokaryoteso One single circular chromosome (in the cytoplasm)o No histoneo No membrane bound organelleso Peptidoglycan cell wall if it’s Bacteriao Produced by binary fission
- • Eukaryoteo Paired chromosome (in the nucleus) – linear chromosomes, not circular,and many of them, not singleo Have histoneso Membrane bound organelles presento Polysaccharide cell wall (if present). Sometimes have peptidoglycan butonly made of carbohydrate but mostly ABSENTo Sexual reproduction
What are monomorphic and pleomorphic organisms?
Monomorphic organism: appear to have same shape under microscopePleomorphic organism: appear with more than one shape under microscope
How do you group bacterial cells based on shape?
Bacillus (rod-shaped)Coccus (Spherical)Spiral- Spirillum, vibrio, and spirochete
How do you group bacterial cells based on arrangement of daughter cells? can onlydivide along the width, not the length à that’s why no stephbacilli
- Single bacillus
- • Diplobacilli – 2 daughter cells
- • Streptobacilli – multiple daughter cells
- • Coccobacillus – circular daughter cells
What is the nature of a bacterial cell wall? What is the function of a cell wall?
- • Cell wall prevents osmotic lysis and made of peptidoglycan (in bacteria)
- • Functions: used to distinguish between (+)gram and (-)gram cells base on stain,maintain shape, accumulation of nutrients, protection from bacteria outside cell(from antibodies or immune system)
What are the sugar components of peptidoglycan?
- Peptidoglycan is polymer of disaccharide:
- • NAG- N-acetylglucosamine
- • NAM- acetylmuramic acidGlycosidic linkage: caused by joint of disaccharide
Differentiate between a Gram--‐‑positive and a Gram--‐‑Negative cell wall.(thickness ofpeptidoglycan, presence or absence of teichoic acid and lipopolysaccharide, presenceof an outermembrane)
- • Gram positive Bacteria cell wallo Thick peptidoglycan cell wall (many layers)o Presence of lipoteichoic acid in cell wallo Absence of outer membrane
- • Gram negative Bacteria cell wallo Thin peptidoglycan cell wall ( single layer)o Presence of LPS- lipopolysaccharideo Presence of outer membrane
Why do we have to worry about the lipopolysaccharide (LPS) of Gram--‐‑negativebacteria? (endotoxin)
It’s more dangerous for Gram negative bacteria if having infection because LPS isantigen- foreign body that stimulates immune system to produce antibodies so verydangerous for bacteria.
What is an Acid--‐‑Fast cell wall? Give bacterial examples.
- • Like gram-positive cell wall
- • Waxy lipid (mycolic acid) bound to peptidoglycan
- • Examples: mycobacterium and Nocardia
What component of the bacteria is responsible for the “Acid--‐‑Fast”ness? (mycolicacid)
Acid-Fast cell wall doesn’t is like gram positive which doesn’t have the outer membranebut having mycolic acid so use acid-alcohol mixture (carbonin fuchsin) to dissolvemycolic acid first, then it can dehydrates peptidoglycan for staining.
Do Mycoplasma species have cell wall? What is unique about their cytoplasmicmembrane?
Mycoplasma species lack cell wall, have sterols in plasma membrane
What is the effect of penicillin on bacterial cell wall?
Penicillin inhibits peptide bridges in peptidoglycan à sensitive to gram(+)
What is the effect of lysozyme on bacterial cell wall?
Lysozyme digests disaccharide in peptidoglycan – attack monosaccharide linkage soprevents disaccharide formationà sensitive to gram(+)
What are protoplasts, spheroplasts and L forms?
- • Protoplast is a gram(+) bacteria, it’s a wall-less cell
- • Spheroplast is a wall-less gram(-) cellà They’re both susceptible (likely to be influenced) to osmotic lysis meaningcause cell burst because H2O move in cell in hypotonic solution
- • L forms are wall-less cells that swell into irregular shape
What is a glycocalyx? What are the two types of glycocalyces?
- • Gelatinous, sticky substance surrounding the outside of the cell
- • Composed of polysaccharides, polypeptides, or both
- • 2 types: capsules, slime layer
Name some functions of glycocalyces. (pathogenicity, virulence factor, preventsphagocytosis, allows attachment to cause infection, can be used in diagnostics)
- • Both capsule and slime layer are virulence factor which means the presence ofthose makes bacteria cause serious infection
- • Capsule
- o Firmly attached to cell surface
- o May prevent bacteria from being recognized by host (phacocytosis) àprevent bacteria from our immune system
- • Slime layer
- o Loosely attached to cell surface
- o Water soluble
- o Sticky layer allows prokaryotes to attach to surface
- o Prevent bacteria from immune system
What do you know about these following terms with respect to flagellararrangement? Atrichorus, peritrichorus, lophotrichorus, monotrichorus,amphitrichorus, and polar
- • Atrichoru: no flagella
- • Peritrichous: many everywhere- all over the place
- • Monotrichous and polar: one flagella
- • Lophotrichorus and polar: many in 1 end
- • Amphitrichorus and polar: 2 in both ends
- • Polar means the ending (can be 1 or 2)
What are the three regions of prokaryotic flagella?
Filament, hook, and basal body (located in cell wall in prokaryotes and cytoplasm ineukaryote)
The filament of the flagella is made of what protein?
What is the difference between a prokaryotic and an eukaryotic flagella?
- • Made up of flagellin
- • Movement: rotate flagella to run or tumble
- • Basal body is in cell wall
- • Plasma membrane doesn’t surround the entire flagellaEukaryote
- • Made up of microtubules
- • Movement: push or drag organism
- • Basal body is in cytoplasm
- • Plasma membrane surround the entire flagella
What is an endoflagella? What kind of organisms possesses them?
Endoflagella is also called endoflagella. Spirochetes organisms possess them, anchoredat one end of a cell, rotation causes cell to move (meaning flagella coil around body, itrotates to make body rotate as wellà movement)
What are fimbriae? How are they different from flagella or pili? What is theirfunction?
- • Sticky, bristlelike projections
- • Function: used by bacteria to adhere to one another to hosts, and to substances inenvironment, also used for movement
- • Shorter and more rigid then flagella
- • Shorter than pili
What are pili? What is their function? What are they made off?
- • Composed of pilin
- • Also known as conjugation pili
- • Longer than fimbriae but shorter than flagella
- • One or two per cell
- • Mediate the transfer of DNA from one cell to another (conjugation)- createmating tube to exchange/transfer DNA in generations (not reproduction)
- • During conjugation, plasmid is transferred to a receiver bacteria from a giverà receiver becomes resistant to some antibodies (can be used for diagnosis).Plasmid can give resistence to more than 1 antibodies using different enzyme
How the plasma membrane is organized in prokaryotes? What are theymade off? What is their function?
- • Plasma membrane is liquid phospholipid bilayer
- • Have hydrophilic (polar) head face the outside and hydrophobic (nonpolar) tailface the inside and have membrane proteins
- Function: communication through membrane proteins, control what and whatcannot get into cell (charge, big, hydrophilic molecules cannot)•
What are the different types of membrane proteins? What is a transmembraneprotein?
- • Peripheral proteins: bound to the surface of the membrane, not embedded in thelipid bilayer, easily dripped off
- • Integral proteins: attaches to the hydrophobic tail of plasma membrane so it’shard to dripped off
- • Transmembrane proteins: expand entire with the membrane
- • Functions: transporter, acting as receptor to receive signals, communications tobring nutrients inside
What is the consistency of a plasma membrane? What kind of movements domembrane lipids and proteins exhibit, lateral or transverse?
- • Membrane is as viscous as olive oil meaning everything on membrane constantlymove à membrane isn’t not rigid, stable
- • Membrane proteins move to function
- • Lipid and proteins exhibit lateral movement à no transverse movement – nochange in movement types
What is passive transport and how is it different from active transport?
- Passive transport
- • No energy input needed because move from high to low concentration
- • Diffusion movement of molecules from high to low concentration, doesn’t involveprotein
- • Facilitate diffusion
- • Osmosis- movement of waterActive transport
- • Energy input needed because move from low to high concentration
- • Need membrane proteins carriers
- • Uniport
- • Cotransport (symport and antiport)
What is simple diffusion? How is it different from facilitated diffusion?
- • Simple diffusion: movement of solute from high to low concentration, doesn’tinvolve protein (Ex: movement of gas)
- • Facilitate diffusion: solute moves with the help of a transporter protein in themembrane. Transporter protein has halocord for solute to move in:o Nonspecific: anything fit in diameter can go ino Specific: transport only specific molecules that fits channel shape
What is osmosis? If water has to be transported by facilitated diffusion, what kindof protein do they use for the transport?
Osmosis is the passive transport of water molecule. If they have to be transported byfacilitated diffusion, they use aquaporin proteins for the transport
What is uniport, cotransport, symport and antiport?
- • Uniport: movement of 1 molecule in 1 direction
- • Cotransport: 2 molecules move together at the same time
- o Symport: same direction. Ex: movement of Na and glucose
- o Antiport: opposite direction. Ex: movement of Na and
What is an isotonic, hypotonic and hypertonic solution? What do you expect when you place a protoplast (wall less cell) in any of these solutions?
- • Isotonic solution: No net movement of water – no differences in concentration sohaving the equal water moving in and out. Cell stays the same
- • Hypotonic solution: Concentration in > concentration out so water move in cell.In organism with cell wall, cell will swell. Protoplast doesn’t have cell wall socell will burst
- • Hypertonic solution: Concentration out > concentration in so water will move outof cell à cell shrinks (plasmolysis) – same with protoplast
What is a cytoplasm?
The entire substance inside the plasma membrane except nucleus, have all structuresuspended (nucleus, plasmids…)
What is a nucleoid?
Bacterial chromosome- have protein attached
What are plasmids?
Extracellular smaller circular DNA molecules, independent of the main bacterialchromosome
What are ribosomes? What are ribosomes made off? What is their function?
Non-membrane bound structure that is a protein synthesizing machinery (function-protein synthesis), made of protein and rRNA
Prokaryotes carry 70S or 80S ribosomes? What are the two subunits of prokaryoticribosome?
Prokaryotes carries 70S ribosomes. Two subunits are 50S and 30S
Name some bacterial inclusion bodies. What is the purpose of inclusion bodies?
- • Serve as energy storage, depend on species if they have all f the inclusions or not
- • Metachromatic granules (volutin)- phosphate reserves
- • Polysaccharide granules – energy reserves
- • Lipid inclusions- energy reserves
- • Sulfur granules- energy reserves
What are endospores? When do bacterial cells sporulate?
- • Spores that form inside cell for survival purpose. Not true spore – offspringspore. Bacteria turn to endospore when they undergo stress, such as increase inheat or lack of nutrient.
- • They’re extremely resistant to desiccation, heat, chemicals
- • Sporulation: endospore formation
- • Germination: return to vegetative state
- • Bacterial cells sporulate when
What are the different layers of coverings you see in an endospore?
[External – internal] spore septum- 2 layers of plasma membrane – peptidoglycanbetween 2 membranes- spore coat
Endospores, are they reproductive spores- offspring spore?
No they’re not. Sporulation: living cell die after producing spores (triggered by lack ofnutrient) while reproduction: living cell produce spore to produce another living cell(both survive)
Can endospores be destroyed easily?
No have to achieve certain degree of Temperature or pressure to destroy them
What are central, subterminal and terminal spores?
- • Central spores: formation of endospores right in the middle of organism
- • Subterminal spores: formation of endospores slightly away from end of organism
- • Terminal spores: formation of endospores at the end of organism
How eukaryotic flagella are different from prokaryotic flagella? (protein component, way they move, location of the basal body)
- Made up of flagellin
- •Movement: rotate flagella to run or tumble
- •Basal body is in cell wall
- •Plasma membrane doesn’t surround the entire flagella
- EukaryoteMade up of microtubules
- •Movement: push or drag organism
- •Basal body is in cytoplasm
- •Plasma membrane surround the entire flagella
How the microtubules are arranged in a eukaryotic flagellum and cilia?
Microtubules is made of tubulin arranged in 9 pairs (doublet microtubules) + 2 arrays (central microtubules)
What is the difference between prokaryotic and eukaryotic cell wall?
- • Prokaryote: Have peptidoglycan cell wall if its bacteria
- • Eukaryote: Polysaccharide cell wall of present but mostly absence of cell wallo In plant, algae, fungio Made of carbohydrates like cellulose (glucan) , chitin (mannan)
What is glycocalyx in a eukaryotic cell?
- • Is the carbohydrate (polysaccharides) that stick out of phospholipid bilayer-carbohydrates extending from animal plasma membrane that bonded to proteinsand lipid in membrane. Function: cell interaction. Pathogen use polysaccharidesto recognize the cell they infect.
- • Lack of capsule and slime layer with present in prokaryotes
What are the similarities and differences between prokaryotic and eukaryoticplasma membrane?
- • Similarities: both have phospholipid bilayers
- • Differences:o Prokaryote: no sterolo Eukaryote: have sterol (fat)
What is endocytosis, exocytosis, phagocytosis and pinocytosis?
- • Endocytosis: bring molecules from outside to inside cell
- o Phagocytosis: pseudopods extend and engulf particles
- o Pinocytosis: membrane folds inward, bringing in fluid and dissolvedsubstances
- Exocytosis: bring molecules from inside to outside cell•
What type of ribosomes do you see in eukaryotic cells?
- • 70S (present also prokaryote 50S + 30S): in chloroplasts and mitochondria
- • 80S (60S + 40S): membrane-bound: attach to ER, free in cytoplasm
Name some organelles present in eukaryotic cells. What is their function?
- • Nucleus: contains chromosomes
- • ER: transport network- smooth and rougho Smooth ER: with no ribosome: lipid synthesiso Rough ER: with ribosome: protein synthesis
- • Golgi complex: membrane formation and secretion
- • Lysosome: digestive enzyme
- • Vacuole: brings food into cells and provide supports
- • Mitochondrion: cellular respiration- double membrane bound, have circularDNA, for ATP sysnthesis
- • Chloroplast: photosynthesis, have circular DNA, 70S ribosome
- • Peroxisome: oxidation of fatty acids, destroy H2O2
- • Centrosome: consists of protein fibers and centrioles, play role in mitosis, it’s notmembrane bound organelle
Define metabolism, catabolism and anabolism.
- • Metabolism: the sum of all the chemical reactions in an organismo Catabolism: provides energy and building blocks for anabolism – breakdown big molecules into small (breaking glucose)o Anabolism: uses energy and building blocks to build large molecules –synthesize small molecules into big ( making glycogen from glucose)
- • Anabolism use energy ATP from catabolic reaction. Catabolism breaks downmolecules release energy ATP for anabolic reaction
What are amphibolic pathways?
Metabolic pathways that have both catabolic and anabolic functions (Crebbs cycle)
What are enzymes? What is an apoenzyme, cofactor, coenzyme, holoenzyme?
- • Enzyme: biological catalyst that speeds up the reactions by lowering theactivation energy and never get consumed in the reaction, it’s specific for achemical reaction
- • Apoenzyme: protein component - inactive
- • Cofactor (metals): nonprotein component – activatoro Coenzyme: organic cofactor (vitamins) need for enzyme to be functional
- • Haloenzyme: apoenzyme + cofactor = complete active enzyme
Give some examples of coenzymes.
- • NAD+
- • NADP+ à both derived from Nicotinic Acid
- • FAD
- • FMN à both derived from riboflavin (B2)
- • Coenzyme A: derived from Pantothenic Acid (Vitamin B5)
How enzymes increase the rate of a reaction?
Enzyme accelerate reaction velocity by lowering the activation energy
What are the different classes of enzymes
- Oxidoreductase: oxidation- reduction reactions
- Transferase: transfer functional groups
- Hydrolase: Hydrolysis
- Lyase: removal of atoms without hydrolysis
- Isomerase: rearrangement of atoms
- Ligase: joining of molecules, uses ATP
What is the effect of temperature, pH and substrate concentration on an enzymecatalyzed reaction?
- • Temperature: enzyme activity increases with increasing T until the enzyme isdenatured by heat and inactivated à works best at optimum T
- • pH: enzyme works best at pH 5.0 à pH< pH5.0<pH , enzyme activity decreasesbecause enzyme denatures
- • Substrate concentration: reaction increases with increasing substrateconcentration until all active sites on enzyme are filled. At that point, reactiondoesn’t change even when adding more substrate concentration
What are the two types of enzyme inhibition?
Competitive and noncompetitive inhibition
What is competitive inhibition? Give an example.
Enzyme inhibitor competes with substrate to bind to enzyme active site --> alter enzymeactivity --> decrease reaction rate. Reverse by removing inhibitor or increasing substrateconcentration so it increases chances that substrate binds to enzyme active site.Example: Sulfanilamid (Sulfur drug) competes with PABA
What is non--‐‑competitive inhibition or allosteric inhibition?
Enzyme inhibitor doesn’t compete with substrate for enzyme active site, instead, it bindsto allosteric site --> alter conformation of protein --> lost active site --> substrate can’tbind --> decrease reaction rate. ( Not all Allosteric regulators are inhibitors, some areactivator that change conformation that substrate prefers to bind)
What is feed back regulation? What are the two types of feedback regulation?
The end products activate/stimulate the early part of the pathway. Two types of feedbackregulation are positive feedback (stimulation) and negative feedback (inhibition)
What is substrate--‐‑level phosphorylation and oxidative--‐‑phosphorylation?
- • Substrate level phosphorylation is generation of ATP directly from metabolicpathway. Energy from the transfer of a high energy PO4 – to ADP generates ATP
- • Oxidative phosphorylation: generation of ATP in ETC, energy released from thetransfer of electrons (oxidation) of one compound to another (reduction) is usedto generate ATP in the ETC.
In what forms energy is extracted from fuel molecules?
ATP, NADH, FADH2
Energy extracted as NADH and FADH2 need which pathway to convert the energyto ATP?
Electron transport chain
What is cellular respiration? When is it aerobic/anaerobic?
- • Respiration: completely oxidize organic molecules and extract energy during theprocess.
- • Aerobic respiration requires oxygen to generate ATP while anaerobic respirationdoesn’t require oxygen
How aerobic respiration is different from anaerobic respiration?
- • Aerobic respiration: the final electron acceptor in the ETC is molecular oxygen(O2)
- • Anaerobic respiration: the final electron acceptor is N, S not O2. Yields lessenergy than aerobic because only part of Krebs cycle operates under anaerobicrespiration
What are the three essential pathways to complete respiration? What is thesubcellular location of these pathways in prokaryotes and eukaryotes?
- • 3 pathways are: glycolysis, Krebs cycle, and ETC
- • Prokaryote
- o Glycolysis: cytoplasm
- o Intermediate step: cytoplasm
- o Krebs cycle: cytoplasm
- o ETC: plasma membrane
- • Eukaryote
- o Glycolysis: cytoplasm
- o Intermediate step: cytoplasm
- o Krebs cycle: mitochondrial matrix
- o ETC: mitochondrial inner membrane
What are the two stages of glycolysis?
Preparatory Stage and Energy conserving stage
What is the starting material and the end product(s) of glycolysis?
Starting material is glucose and end product ares two 3C molecules (1st stage) and 2pyruvic acids (2nd stage)
What is the net ATP yield from glycolysis for a single molecule of glucose?
What is the net ATP yield through substrate level phosphorylation from glycolysisfor a single molecule of glucose?
4 ATP produced – 2 ATP used = 2 ATP
What is the net NADH yield from glycolysis from a single molecule of glucose?
What is the net energy yield (in terms of ATP) from glycolysis from a singlemolecule of glucose?
2 ATP + ( 2 x 3ATP)NADH = 8ATP
What is the net NADH yield from the step that converts pyruvate to acetyl CoA, fora single molecule of glucose?
2NADH = 6ATP
Why the conversion of pyruvate to acetyl CoA is an oxidative decarboxylationreaction?
Pyruvate gets oxidized (meaning, releases electrons) and simultaneously loses acarbon in the form of CO2. Therefore, this step is called oxidative decarboxylation
What is the net ATP yield from TCA cycle for a single molecule of glucose?
2ATP in 2 cycles
What is the net ATP yield through substrate level phosphorylation from TCA cyclefor a single molecule of glucose?
What is the net NADH yield from TCA cycle from a single molecule of glucose?
6 NADH in 2 cycles
What is the net FADH2 yield from TCA cycle from a single molecule of glucose?
2FADH2 in 2 cycles
What is the net energy yield (in terms of ATP) from TCA cycle from a singlemolecule of glucose?
2ATP + (6 x 3ATP) NADH + (2 x 2 ATP) FADH2 = 24 ATP
What is the purpose of the electron transport chain? (transport electron & pumpproton)
Transport electrons to create proton gradients by bumping proton out
Which is the non--‐‑protein component of the electron transport chain?
Q- ubiquinone: derived from vitamin K, functions by itself, doesn’t need a proteincomponent to work.
What is the terminal electron acceptor of the ETC in aerobic animals?
Oxygen – O2
What is the terminal electron acceptor of the ETC in anaerobic animals?
In which subcellular location the proton gradient is created when electrons travelthrough the ETC?
- • Prokaryote: Periplasmic space (Space between cell wall and cell membrane)
- • Eukaryote: Inter membrane space
What is ATP--‐‑synthase/ATPase? What are its functions?
It’s not part of ETC, function is to pump proton from outside to inside cell, catalyzephosphorylation of ADP to ATP
What are flavoproteins?
FMN: flavinmononucleotide and FAD: flavinadeninednucleotide that both derive fromriboflavin. Flavoproteins are proteins that use FMN or FAD as coenzyme
What are cytochromes?
Proteins (cyt) that contains HEME as cofactor
What is fermentation? How is it different from respiration?
• Partial break down of organic molecules• Compared to respiration, fermentation doesn’t use Krebs cycle or ETC, usesorganic molecules as the final electron acceptor (inorganic in respiration whichis O2)
What is the purpose of fermentation?
To regenerate NAD+ for more energy synthesize process
Name some end products of fermentation.
Alcohol, lactic acid, ethanol…
What are homolactic and heterolactic fermenters? Give one example for each.
- • Homolactic fermentation: produce lactic acid only
- • Heterolactic fermentation: produce lactic acid and other compounds
Name a biochemical test that relies on fermentation. How this test can be useful?
Mannitol test, it can be useful because S.epidermidis and S.aureus are clustered togetherso it’s hard to differentiate between them. Using mannitol test --> S.epidermidis is grampositive bacteria so doesn’t ferment mannitol while S.aureus does --> tell them apart
What is the lipid that is used for energy purposes? (triacylglycerol)
What is the enzyme that releases the fatty acids from glycerol?
What happens to the glycerol released from triacylglycerol?
Glycerol --> dihydroxyacetone phosphate --> glyceraldehyde 3-phosphate –Glycolysisàpyruvic acid --> Acetyl CoA --> Krebs cycle
What is the name of the process that releases acetyl CoA from fatty acids?
What happens to the acetyl CoA released from fatty acids?
Go to Krebs cycle
What is the enzyme released by prokaryotic cells to digest proteins?
What happens to the amino acids released from proteins?
Can go under deamnination/decarboxylation/dehydrogenation/desulfurylation to becomeorganic acid then go to Krebs cycle
What is the principle behind the urease test?
To test if organism contains urease by putting organism in the medium; if it containsurease, it will break Urea into NH3 (acid) + CO2 which increase pH à change in color
What is the principle behind the desulfurylation test?
To test if organism can remove Sulfur group, if it can remove it, then can see bacteriagrowth
How living things are classified based on their carbon source?
- • Autotroph: use inorganic compounds for C source
- • Heterotroph: use organic compound for C source
How living things are classified based on their mode of energy extraction?
- • Phototroph: use light as energy
- • Chemotroph: use chemical compound for energy
What does growth mean in the microbial world?
The increase in number of cells, not cell size
What are colonies/biofilms?
Big group of cells, every single cell is the replication of the single cell
What are psychrophiles, mesophiles, thermophiles and hyperthermophiles?Organisms pathogenic to human belong to which group?
- • Psychrophiles: cold T lover, can grow at O deg. but no above room T à notconcern of food poisoning
- • Mesophiles: body T lover à pathogenic to human
- • Thermophiles: higher T loverà doesn’t cause disease at room T
- •Hyperthermophiles: really high/hot T lover à doesn’t cause disease at room T
What are psychrotrophs? Why are they relevant?
They can grow at low T (0 deg.) and room T (30 deg.) so à food poisoning
What is an optimum growth temperature?
Is the T that organism grow the best
What are acidophiles, alkalinophiles, halophiles?
- • Acidophiles: organisms that grow in acidic environment (stomach)
- • Alkalinophiles: organisms that prefer alkaline environment
- • Halophiles: organisms that prefer salty environment
Why organisms need nitrogen? How do they obtain nitrogen?
- • Organisms need nitrogen to synthesize amino acids, to synthesize nucleotidebases and of course, anaerobic organisms need them as electron acceptors. Theyget nitrogen through nitrogen fixation or from ammonia or from other decayingmatter or from recycling their own proteins.
- • They obtain using nitrogen fixation, only N fixation can convert N into usefulform
What are obligate aerobes/obligate anaerobes? Why one can tolerate oxygen and theother cannot? (presence of superoxide dismutase, catalase, peroxidase)
- • Obligate aerobes: organism that need oxygen for life à only grow on surfaceof the tube where has high concentration O2. Presence of enzyme catalase andsuperoxide dismutase allows toxic forms of O2 to be neutralized, so they can useO2 (produce all 3 types of antioxidants)
- • Obligate anaerobes: organisms that hate O2, growth occur only where there isno O2. Lacks enzymes to neutralize harmful forms of Oxygen, cannot tolerate O2.(they can’t produce antioxidant)
- • Some can tolerate oxygen and the other can’t because of presence of superoxidedismutase, catalase, peroxidase – antioxidants (in those who tolerate) put free-radicals of O2 back to normal form (oxidant is toxic to body) while those whocan’t tolerate O2 can’t produce antioxidant so very dangerous to body.
What are facultative anaerobes? How are they different from aerotolerantanaerobes?
- • Facultative anaerobe: organisms that have both aerobic and anaerobic growth ,but have greater growth in presence of O2 à ability to tolerate O2 (produce 3types antioxidants) à grow better with O2 but doesn’t require it
- •Aerotolerant anaerobes: only anaerobic growth but can also grow in the presenceof O2, so growth occurs evenly à O2 has no effect, can grow with or withoutoxygen (produce 1 or 2 types of oxidants)
What are microaerophiles?
Only Aerobic growth, require O2 in low concentration (~5% O2 saturation) (producedvery little antioxidant)
Name some free radicals (reactive oxygen species; oxidizing agents) produced byorganisms. (superoxide, peroxide, singlet oxygen, hydroxyl radical)
- O2 ---------> H20 + H20
- 4 e- never goes at the same time, but one by one so become free-radical which is verydangerous for body. Body produces antioxidant to counteract it.Free radicals: superoxide, peroxide, singlet oxygen, hydroxyl radical
What are antioxidants? Name some natural antioxidants.
A substrate that reduces damage due to O2 that caused by free radicals, they’reproduced naturally by the body to put free radicals back to normal form.Antioxidants: superoxide dismutate, catalase, and peroxidase
What are biofilms? Through what mechanism organisms communicate with eachother within a biofilm?
• Biofilms are community of coexisting organisms, they’re microbial communities.•Organisms communicate with each other within a biofilm via quorum sensingmechanism which means they can sense concentration by counting number oforganisms exist in the community. They do that buy receiving and secreting signalfrom/to other organism. By that, they will send out enzyme to make disease whenthere are millions of them so immune system can’t kill them off. They don’t firedisease when community is small because immune system can kill them sincethey’re weak.
Where do you see biofilms?
Human hair, tooth
What is a bacterial colony?
Visible cluster of bacteria growing on the surface or within a solid medium, culturedfrom a single cell.A colony is a population of cells arising from a single cell or spore or from a group ofattached cells
What features of the colony can be used to identify bacteria?
Shape, margin, elevation, size, texture, appearance, pigmentation-color, opticalproperties
What is a colony--‐‑forming unit (CFU)?
An estimate of viable bacterial or fungal number (unlike direct plate count that all cells,dead and living, are counted, CFU only estimates the viable cells, a colony is often calleda CFU
What is an agar?
- • Complex polysaccharide, seaweed extract used to as solidifying agents for culturemedia in petri plates, slants, and deeps
- • Generally hot metabolized by microbes
- • Liquefies at 100 C, solidifies at 40C
5. Why is agar preferred to solidify culture media?
Because agar is neutral, bacteria can’t dissolve carbohydrates so they don’t utilize agaras nutrition and agar doesn’t melt as room Temperature
What is a chemically defined medium?
Exact chemical composition is known
What is a complex medium?
- Extracts and digests of yeasts, meat, or plants à don’t know exactly what thecomponents are, just simply put the exacts in
- • Nutrient broth
- • Nutrient agar
When is a complex medium preferred over a defined medium?
When we don’t know the exact nutrients organisms need, in this case, can’t use a definedmedium
What are selective media? List some methods of selection (answer: addingmore salt to select for salt--‐‑tolerant bacertia; adding bile salt to select for gramnegative organisms; adjusting the pH to the acidic side to prevent bacterial growthduring fungal culture, etc).
Media that suppress unwanted microbes and encourage desired microbes à selectinggrowth for some organisms by inhibiting growth of others
What is a differential media?
Medium used to distinguish colonies of different microbes because organisms usecomponents in plate differently.Examples: blood agar and MacConkey agar
How blood agar is used to differentiate between bacteria?
- Differentiate them base on whether they utilize RBC
- • S.pneumoniae- alpha hemolysis – hemolize RBC a little -> glow little
- • S.pyogenes- beta hemolysis – completely hemolize RBC--> glow a lot
- • Enterococcus faecalis- gamma hemolysis – doesn’t hemolize RBC --> no glow
What are the different kinds of hemolysis noticed on a blood agar?
Alpha, beta, and gamma hemolysis à blood agar is differential media not selective
What kind of medium is a MacConkey Agar? Name some anaerobic culturetechniques? (reducing media; anaerobic jar; anaerobic chamber)
- • Mac Conkey agar is selective and differential medium, it’s selective for gram-negative cells (presence of bile salt: only gram-negative can grow on it) anddifferentiate between gram-negative cells by lactose fermentation.
- o Lactose: ferment lactose, produce acid, color changes, appear pink
- o No lactose: no change in color
- • Anaerobic culture techniques
- o Reducing mediao Anaerobic jar
- o Anaerobic chamber
What is present in a reducing medium that takes away the oxygen?
Reducing medium contains chemical (thioglycolate) that combine with O2à trap O2,hold on to them so they can’t dissolve over the place à heated to drive off O2
Can all bacteria be cultured in a lab? Name some alternate bacterial culturetechniques (animal culture for Mycobacterium leprae; cell culture for Chlamydia).
- • Not all bacteria can be cultured in a lab
- • Techniques developed for culturing certain microorganisms (all are living cells)o Animal culture for mycobacterium lepraeo Cell culture for Chlamydia à intracellular so can’t keep them in solid/liquid medium, they have to grow inside cello Enrichment culture
What is an enrichment culture?
- • Encourages growth of some desired microbes
- • Assume a soil sample contains a few phenol-degrading bacteria and thousandsof bacteria (transfer medium with phenol bacteria to a fresh medium à enrichphenol growth)
- o Inoculate phenol-containing culture medium with the soil, and incubate
- o Transfer 1ml to another flask of the phenol medium, and incubateo Only phenol-metabolizing bacteria will be growing
What are capnophiles?
- • CO2 loving organisms -> love low oxygen culture or CO2 culture
- • Microbes that require high CO2 condition
- • CO2 packet, candle jar (can’t burn all O2)
What is the most common method used to obtain pure culture of bacteria?
Streak plate method
Name some bacterial preservation techniques employed routinely? Know thetemperature conditions.
- • Deep- freezing: -50C to -95C
- • Lyophilization (free-drying): frozen (-54C to -72C) and dehydrated in a vacuumà use mechanism of sublimation (solid --> gas, no liquid state)
What are the various phases of growth? Know about each of them.
- • Lag phase: no growth, organisms check out conditions à synthesize enzyme toget ready for replication
- • Log phase: growth starts, linear growth, unlimited supplies
- • Stationary phase: # organisms produced = # organisms died and run out ofnutrients
- • Death phase: # organisms produced < # organisms died , completely run out ofnutrients
What is the preferred bacterial growth phase for gram stain/introduce foreignDNA/antibiotic treatment?
Log phase because antibiotic acts on replicating cells so it can stain better
What is binary fission?
Asexual reproduction, used by prokaryotes
What is a “generation time”? (Questions on calculating the number of bacteria/number of generation/generation time are highly likely).
Time to double population in log phase
Name some direct and indirect ways of estimating bacterial growth.
- • Direct methods (count organisms)
- o Plate counts: for small numbero Filtrationo MPN
- o Direct microscope count
- Indirect methods (count things organisms produce)•
- o Turbidity: amount of light detected depend on amount of light observedby organisms -> more organisms, less light reach detector. If moreorganisms, tube is more cloudy/turbid
- o Metabolic activity: measure source of energy (glucose) that is used -> measure # of organisms grown in the culture (can also measure endproduct appearance or start material disappearance)
- o Dry weight
Know the terminologies used in the context of microbial growth control.
- • Sterilization: removing all microbial life
- • Commercial sterilization: Killing C.botulinum endospores in canned food usingheat
- • Disinfection: removing pathogens = destruction of vegetative (non-endosporeforming) pathogens
- • Antisepsis: removing pathogens from living tissues
- • Degerming: removing microbes from a limited area
- • Sanitization: lowering microbial counts on eating utensils
- • Biocide: Kills the organisms, Bactericide, Fungicide, Virucide
- • Biostatic: stops the growth of the organisms (when organisms secret things-enzymes that when released are more dangerous that organisms themselves sodon’t kill them)
- • Sepsis: refer to microbial contamination
- • Asepesis: absence of significant contamination, aseptic surgery techniquesprevent microbial contamination of wounds
How is sterilization different from disinfection /antisepsis /sanitization degerming?
- • Sterilization: removing all microbial life except prions , used on inanimatesubjects, not human being
- • Disinfection: removing pathogens, used on inanimate subjects, not completelyremove everything (not endospores, not on skins) (Ex: wash home bathroom)
- • Antisepsis: removing pathogens from living tissues
- • Santization: lowering microbial counts on eating utensils à used in public healthsetting to meet public standard (Ex: cleaning public restroom in a restaurant)
- • Degerming: removing microbes from a limited area, remove by scrubbing anarea, doesn’t matter what agents are used (Ex: skin is swabbed with alcoholbefore injection)
What infectious agent is resistant to sterilization? (Answer: Prions infectiousproteins)
Prions infectious proteins
What is a microbicide (microbicidal agent)?
Agents that kill the organism
What is a microbistatic agent?
Agents that stops or slows down the growth of organisms
What are the factors that influence the microbial growth control process/treatment?
- • Number of microbes
- • Environment (organic matter, Temperature, biofilms)
- • Time of exposure: depend on concentration, nature of chemical/surface, numberof organisms present
- • Microbial characteristics
- • Immune system
What are the modes of action of microbial growth control agents?
- • Alternation of membrane permeability: destruct integrity of cells
- • Damage to proteins: destruct metabolisms of cell
- • Damage nucleic acids
Name some physical agents that can be used to control microbial growth?
Heat, temperature, pressure, radiation
Name some techniques that apply moist heat?
Sterilization, autoclave, pasteurization, boiling
How to monitor the efficiency of an autoclave?
- • Autoclave is steam under pressure = preferred method of sterilization. It’smost effective when organisms either are contacted by the steam directly or arecontained in a small volume of aqueous liquid.
- • Steam at pressure of ~15psi (121C) will kill all organisms and their endosporesin 15 minutes
- • Disadvantage: doesn’t kill prions
35. Why is moist heat better than dry heat?
Moist heat is better and more damaging than dry heat because moist heat extractbacteria better and air is thermo heat
What is thermal death point?
Lowest temperature at which all cells in a culture are killed in 10 minutes
What is thermal death time?
Time during which all cells in a culture are killed
What is decimal reduction time?
Minutes to kill 90% of a population at a given temperature
What is pasteurization? Know the pasteurization conditions.
- • Process of heating a food which is usually a liquid to a specific T for a predefinedlength of time and then immediately cooling it after it is removed from the heat
- • Reduces spoilage organisms and pathogens àdoesn’t skill endospores, not kill100%, but just eliminate pathogens
- • Equivalent treatment
- o 63C for 30 minutes
- o High T short time: 72C for 15 seconds
- o Ultra high T: 140C for <1 second
- o Thermoduric organisms survive
Name some techniques that apply dry heat?
- • Flaming
- • Incineration
- • Hot-air sterilizationDry heat is less efficient than moist heat so require longer exposure time
How are heat--‐‑sensitive fluids sterilized?
- Sterilized by filtration (penetration) and radiation
- • Filtration (use filtration not heat because composition of fluid are heat sensitive)o HEPA removes microbes >0.3um
- o Membrane filtration removes microbes >0.22um
- • Radiation: UV light used to sterilization
What are ionizing and non--‐‑ionizing radiations? Give examples.
- • Ionizing radiation (X rays, gamma rays, electron beams)
- o Ionizes water to release OH
- o Damages DNA
- Nonionizing radiation (UC, 260nm-normal range)- Damage DNA•
Through what mechanism do these radiations act?
In nonionizing radiation, UV light damages the DNA by causing bonds to form betweenadjacent pyrimidine bases (usually thymine) cross link them à Thymine dimers inhibitsreplication of DNA during reproduction of cell
Name some chemical disinfectants?
Phenol and phenolics, bisphenols, halogens, alcohol, heavy metals,…
What are the factors that can affect the efficiency of a chemical disinfectant?
Concentration of disinfectants, organic matter, pH, time
How phenol, phenolics and bisphenols act?
- • Phenol and phenolics: disrupt plasma membranesà disrupt protein à effectmetabolism of cells. Disadvantages: can’t use on human because they can alsokill human plasma membrane
- • Bisphenols: hexacholorphene, triclosan disrupt plasma membranes (limit usingtriclosan because bacteria can gain resistance toward it)
What is phenol coefficient?
- Expose number of organism and disinfectant agent to phenol -> compare disinfectantand phenol.
- • >1: agents are better than phenol
- • <1: agents are worse than phenol
Name some halogens and their derivatives that have disinfectant properties?
- • Iodine: is very strong by itself
- o Tinctures: in aqueous alcohol, I dissolves in alcohol
- o Iodophors: in organic molecules
- o Alter protein synthesis and membranes
- • Chlorine: works same way with Iodine
- o Bleach: hypochlorous Acid (HOCl)
- o Chloramine: Chlorine + ammonia
- o Oxidizing agents
What are tinctures and iodophors?
- • Tincture: Iodine + alcohol
- • Iodophors: in organic molecules, iodine attach to any covalent compounds
What is the mode of action of chlorine or its derivatives?
When Cl is added with water, it creates hypochlorous acid (HOCl) which is a strongoxidizing agent that prevents much of cellular enzyme system from functioning
What percent alcohol is very effective as a disinfectant?
75% works best
Which heavy metal containing ointment was used to treat opthalmia neonatorum?
What are quats? What is their mechanism of action?
Quats (Quarternary ammonium compounds- cationic detergents) are amphipathicmolecules, they are bactericidal, they denature proteins and disrupt plasma membrane
Name some aldehydes and gaseous agents used for sterilization purposes.
- o Inactivate proteins by cross-linking with functional groups (-NH2, -OH, -COOH, -SH)
- o Use: sterilize medical equipment: glutaraldehyde, formaldehyde, andortho-phthalaldehyde
- Gaseous sterilantso Denature proteins
- o Use: sterilize heat- sensitive material: ethylene oxide•
What is a “use dilution test” and “disk--‐‑diffusion test”.
- • Use dilution test (put organism in different dilution to test which disinfectantswork better)- not directly testing
- o Metal rings dipped in test bacteria are dried
- o Dried cultures are placed in disinfectants for 10 minutes in 20C
- o Rings are transferred to culture media to determine whether bacteriasurvived treatment
- • Disk diffusion method – In use test: do directly testing in environment
- o Take filter paper disk, put in peri plate, incubate to let organism grow
- o Disinfectant agent from paper will diffuse and spread out of the plate àkill organism. The area where there is no growth of bacteria is called zoneof inhibition
What is chemotherapy?
The use of drugs to treat a any type of disease, doesn’t have to be infectious disease
What are antibiotics?
A substance produced by a microbe that, in small amount, inhibits another microbe
How bacteriostatic agents differ from bactericidal agents?
- • Bacteriostatico Reversibly inhibits growtho Duration of treatment sufficient for host defenses to eliminate infection
- • Bactericidalo Kill bacteriao Preferred for immune system inaccessible sites (endocardium, meninges)
While using the bacteriostatic agent, what kills the bacteria?
When do you call a drug bactericidal, as opposed to bacteriostatic?
- • If concentration to kill is >10 times the concentration to inhibit à microbiostatic
- • If concentration to kill is <10 times the concentration to inhibit à microbiocidal
What are broad spectrum and narrow spectrum antimicrobials?
- • Broad spectrum antibiotics: indiscriminate killing of bacteria (both Gram + andGram -)
- •Narrow spectrum antibiotics: restricted pattern of killing
What are the advantages and disadvantages of using broad spectrumantimicrobials?
- • Advantage: save time because identity of pathogen isn’t always immediatelyknown
- • Disadvantage: may give rise to drug resistance, may destroy many normalmicrobiota of the host à the survivors might flourish and become pathogens
What is therapeutic index and how is it useful?
The ration between the concentration required to hurt the host (high) / concentrationrequired to hurt the prokaryote (low) à high TI is good! TI is minimum does to killbacteria
What are the various mechanisms of action of antibacterial drugs? Which of themwould be exclusively specific to prokaryotes?
- • Inhibition of cell wall synthesis: penicillin, cephalosporins, bacitracin,vancomycin (Side effect: body allergy -> high TI)
- • Inhibition of protein sysnthesis: chloramphenicol, erythromycin, tetracyclines,streptomycin (Not as high TI as 1) because of presence of ribosome -> side effect)
- • Inhibition of nucleic acid replication and transcription: quinolones, rifampin
- • Injury to plasma membrane: polymyxin B
- • Inhibition of synthesis of essential metabolites: sulfanilamide, trimethoprim
What is beta--‐‑lactams? How do they inhibit bacterial growth?
Beta-lactams (Penicillin) are antibiotics that inhibit the growth of bacteria byinactivating enzymes located on bacteria cell membrane; they bind to Penicillin bindingproteins to inhibit those enzymes to prevent peptide cross-bridge
What are penicillin--‐‑binding proteins? Give examples.
- • They are groups of proteins that bind penicillin, involve in the final stage ofpeptidoglycan synthesis -> inhibitions of penicillin binding proteins lead toirregularities of bacteria cell wall
- • Examples: Transglycosylase, D-Carboxypeptidase, Transpeptidase
What feature of bacteria makes it resistant to penicillins? (Answer: Penicillinase/beta--‐‑lactamase production)
Bacteria produce penillinase (beta-lactamase) which are enzymes that act on penicillinto destroy them à organism is free to go and develop resistance to penicillin
Name some non--‐‑beta lactam cell wall synthesis inhibiting antibiotics.
INH and ethambutal are used against Mycobacterium sp. How do they act?
- They’re antimycobacterial antibiotics (can’t use in Gram positive and Gram negative)
- • Isoniazid (INH): inhibits mycolic acid synthesis
- • Ethambutol: inhibits incorporation of mycolic acid around bacteria
Name some antibiotics that inhibit bacterial protein synthesis.
- • Aminoglycosideso Streptomycin, Streptomyces sp.
- o Neomycin, gentamycin, amikacin
- § Broad spectrum
- § Changes shape of 30S subunit leading to incorrect reading ofcodons (therefore wrong protein) à permanent binding à lost30S forever
- o Bactericidal: bind permanently to the ribosomes
- • Tetracyclines (Streptomyces sp.)
- o Broad spectrum, bacteriostatic
- o Interfere with tRNA attachment so tRNA can’t bind to amino acids à noprotein synthesis
- o Bacteriacidis: not permanent binding
- o Side effect: color teeth in infant
- • Chloramphenicol (Streptomyces sp.)
- o Broad spectrum
- o Binds 50S subunit, inhibits peptide bond formation so no protein synthesisbecause amino acids are not connected
- o Causes aplastic anemia à inhibits RBC pathway à compromise bonemarrow
- • Macrolides (Erythromycin)
- o Gram positive (narrow spectrum)
- o Binds 50S, prevents transpeptidization amd translocation à preventpeptide linkage
- o Gastric discomfort
Name some antibiotics that inhibit the 30S ribosomal subunit?
How tetracyclines inhibit bacterial growth?
- Tetracyclines (Streptomyces sp.)
- Broad spectrum, bacteriostatic
- Interfere with tRNA attachment so tRNA can’t bind to amino acids à no proteinsynthesis
- Bacteriacidis: not permanent binding
- Side effect: color teeth in infant
Name some antibiotics that inhibit the 50S ribosomal subunit?
Name some nucleic acid synthesis inhibitors? How exactly do they work (whatenzyme do they inhibit)?
- • Rifamycin
- o Inhibits RNA synthesisà inhibits RNA polymerase so can’t produce anytype of RNA
- o Broad spectrum, used only as Antituberculosis
- o Unusual side effect: orange-red body fluids
- • Quinolones and fluoroquinoloneso Nalidixic acido Ciprofloxacin
- o Inhibits DNA gyrase (topoisomerase) in prokaryotes. Gyrase function:eliminate supercoiling of DNA when separate DNA into 2 single strains.Otherwise, not complete replication
- o Urinary tract infections à when drug in kidney: water soluable so kidneycan filter and make them active to transfer to bladder
What is the mode of action of polymyxinB?
- • Injury to the plasma membrane à affect lipid bilayer so affect both prokaryotesand eukaryotes
- • Polypeptide antibiotics
- • Binds phospholipids in the membrane, osmotic imbalance and prevent membranefunction à form channels so things move in/out of cells massively
- • Not very selective, there toxic
- • Topical
- • Combined with bacitracin and neomycin in over the counter preparation
Why sulfa drugs are specific for the prokaryotes?
Sulfa drugs are bacteriostatic (stop bacteria from growing), their action isdue to similar structure to PABA, microbes that are sensitive to sulfa drugsmust synthesize PABA (whereas human ingest it in diet). Sulfa drugs are broadspectrum, they inhibits folic acid synthesis à inhibits DNA/RNA synthesis
What is vertical acquisition of resistance?
Resistance genes are transferred directly to all the bacteria’s progeny by binary fissionduring DNA replication (a spontaneous mutation in the bacterial chromosome givesresistance to a member of the bacterial population)
What is horizontal acquisition of resistance?
Process by which genetic material contained in small packets of DNA (plasmids) can betransferred between bacteria through conjugation.
What are R--‐‑factors?
Resistant factors which come from in form of plasmids acquired by conjugation byhorizontal transport and passed down to progenies by vertical transport.
What are the three medical relevant Staph species?
Presence of what enzyme differentiated a staph species
from strep specie?
- Coagulase --> - in strep, + in staph
Why protein A is a virulence factor (on the cell wall
- Protein A binds antibody at different place so antibody
Toxin of Staphylo
- Cytolytic à disrupt cytoplasmic membrane
- Exfoliative à skin to separate Cuteneous
- Enterotoxin -> food poisoning Systemic, Toxin à responsible for food poisoning
what is S.pyogenes virulence factors
- M protein, which interferes with opsonization
- and lysis of the bacteria
- Hyaluronic acid capsule à prevent phagocytosis
- Cytotoxic: break all open
What chemical nature of the capsule produced by S.
pyogene? Why this capsule cannot be recognized by our immune system?
- Hydrolonic acid made up of capsule and cell make
- up of that acid so immune sys think its own cell
Rheumatic fever and glomerulonephritis are classified
as S.pyogenes disease but why are they call autoimmune disease
- Autoimmune got trigger by previous cased of
- strep throat to heart value
Group A strep disease from pyogenes
CAMP test of strep
- Pyogenes: BAC: Sen | CAMP test: -
- Agalactiae: BAC: RES | CAMP test: +
- Use Bacitracin – CAMP to diff between them
S. Pneumoniae classified as non groupable streptococci
- Present as dental carry flora
- The most prominent factor is large anti
- phagocytic capsule
- test is for identify S.Pneumoniae and presence of capsule
- Pneumococcal polysaccharide vaccine à
- mixture of 23 capsular polysaccharide
- B.Anthracis – Antrax ( gastro, cutaneous,
- Slow healing painless ulcer covered with black
- ESCHAR surrounded by edema
- 100% fatal gastrointestinal
- Treatment: penicillin, Erythro, Chloram
- B.Cereus – Gastroenteritis, ocular infections,
- Capsule is protein amino acid
For anthrax has cap___m \ exotoxin or endotoxin
yes Capsule and exotoxin
which specie of bacilli used for Test for autoclave sterilization
- Bacillus Stearothermophilus
Example of ANAEROBE G+ spore forming bacilli
- Clostridium - soil human intestine
- C. tetani tetanus
- C. botulinum
- C. perfringens gangrene
- C. difficile diarrhea
- Corynebacterium ·
- (club shaped, G+, bacilli)
- Mycobacterium avium-intracellular
- Mycobacterium Tuberculosis
C. tetani tetanus vrulence factor
A-B neurotoxin (tetanospasmin)
- Block release of inhibitory neurotransmitters
C. tetani tetanus: can antibiotic kill?
yes but not the toxin G+
C. tetani tetanus: treatment
- Treatment: passive vaccination Tetanus – Ig
- Passive vaccination: use antibody directly
- Active vaccination: DPT, TT G+
C. botulinum G+: mode of action
- Prevent NT to release Ach à
- paralysis à binding
- is irreversible
C. botulinum G+ toxin?
- Botulism toxin, prevent release of NT Ach à
- muscle not contract à
- INTOXICATION not INJECTION
- Food bourne à asphyxiation
- Infant botulism à ingestion of endospore
- Wound botulism à contamination wound of endospore
C. botulinum G+: kill bacteria --> kill toxin?
C. perfringens gangrene: type of toxin, mode of action
- Lecithinase (detect by Nagler Reaction use Egg
C. perfringens gangrene: what disease?
- Myonecrosis à amputation
C. difficile diarrhea:G+" unique thing about it?
- Normal flora but shit can hit fan after
- treatment of antibiotic
Corynebacterium (club shaped, G+, bacilli): unique thing about it? that can change the stain result?
- Alter the color of particular stain
Corynebacterium (club shaped, G+, bacilli): toxin
- Diphtheria toxin (introduce by lysogenic)
- Toxin interrupts the elongation à
- cant track the RNA à
- interrupt protein synthesis à
- cell die
- Exotoxin A-B neurotoxin
- Produce by TOX gene from bacteriophage
- Pseudomembrane on the tonsil is the sign
- vaccine can prevent the disease
Mycobacterium: virulence factor?
- Virulence factor is the ability to survive
- phagotic cell
- Mycobacterium avium-intracellular
- Common among AIDS patient
Mycobacterium Tuberculosis G+ bacilli
- Responsible for long generation time, inability
- to gram stain and antibiotic resistance
- Lowenstein-Jensen medium to grow
- PDD used to skin test for reaction
- Primary à secondary à disseminated
- Bacillus Calmette & Guerin à
- not patho to human used for V.F. to treat tuber
M. Leprae G+ bac
- Hensen’s disease is leprosy
- + lepromin test is Tubercoid neutral ß
- from weak immu sys
- - Lepromintest is Lepromatous progressive ß from strong immu sys
- affect area of cooler body
G- cocci: that only cause disease in human?
- Neisseria – only G- cocci that cause disease in
Neisseria oxidase test? what medium to grow?
- Oxidase test and diplococci under microscope is
- used to identify them as Neisseria
- Has to use SELECTIVE media. Thayer martin \
- modified TM \ Martin lewis
N. Gonnorhoeae (Gonococcal) G- coc: virulence factor?
- Only fimbriated is virulent
- Cell wall protein promote survivalbility
- Beta-Lactamase positive – resistant to
N. Gonnorhoeae (Gonococcal) : disease transmit by?
- G- coc
- Men à urethritis à discharge shit
- Female à affect cervix, urethra; pharynx \ vagina cannot be
- Pelvic inflammatory disease PID
- Neonatal à SYMP ophthalmia neonatum lead to blindness \ must
- be treat b4 giving birth.
- Find on top of the respiratory tract as flora
- If breach mucosal layer à meningitis
G- bacilli ( live in Enteric which in inside human
- Enterobacteriaceae à oxidase NEGATIVE
- E.coli COLI
- Klebsiella pneumonia COLI
- Serratia COLI
- Mirabilis NONCOLI
- Salmonella NONCOLI ALWAYS PATHO
- Always w/ disease à Shigella, Salmonella (resistance to bile salts)
- Opportunistic flora à E.coli, K.pneumoniae,
- P. mirabilis
- Classified into 3 groups
- Coliforms – present in intestine OPPOR (ecoli)
- True pathogen (shigella salmonella)
- Gastroenteritis: countries with poor hygiene
- Enterotoxigenic à traveller diarrhea
- Enterohemorrhagic à shiga like cytotoxin G-
Klebsiella pneumonia COLI
- In digestive and respiratory
- Opportunistic disease \\\ CAPSULE to protect
- from phagocytosis
- G -
- Turn urea into Co2 and ammonia à
- change renal pH à
- induce pH change BY USING UREASE enzyme
Salmonella NONCOLI ALWAYS PATHO
- S.typhi and S. paratyphi are the pathogenic
- Always small intestine à induce endocytosis and
- kill host à
- cause shits symptom à
- move to blood stream
- Have to take lots of them
Shigella NONCOLI PATHO
- Irreversible 60s INACTIVE à
- no pro. Syn.
- Cytotoxin kill intestinal epithelial
- Target Na+ absorb cells à more fluid accumulate
- in lumen
Yersinia Pestis NONCOLI PATHO direct contact or
- Bubonic plague – animal to H only
- Pneumonic plague - contagious
Pasteurellaceae à oxidase POSITIVE
- Obligate parasite because need cytochrome or
- heme from host to grow
- G- bac