Bacteria Structure, Function, and Pathogenicity Flashcards
What is the difference between eukaryote and prokaryote?
P- small, no nuclear membrane, circular chromosome, 70s ribosome (30s and 50s subunits), cell wall peptidoglycan (complex); E- large, nuclear membrane, linear multiple chromosomes, 80s ribosome (40s + 60s), wall of cellulose or chitin (simple)
What are the various staining reactions? What reagents are used?
gram staining (crystal violet, iodine, acetone, safranin), acid fast (carbolfuschin, heat, acid/alcohol pulls from non-acid fast, add methylene blue), immunoflourescent (Ab labeled w/ fluorescence to a cell wall component), geimsa stain, silver impregnation
What are the morphology of bacteria?
cocci (clusters, chain, diplococcic), bacilli (coccobacilli, vibrios, fusiform), spiral (spirochetes), and other (diptheroid, pleomorphic- clubbed, branched, filamentous, irregular, Chinese letters)
What are the general features of a gram positive cell?
cell wall has teichoic acid on the outer surface (roll in virulence), has pili (fimbriae), possibly a singular flagella and a capsule
What are the general features of a gram negative cell?
outer membrane with porins and adhesion sites, periplasmic space, inner membrane made of peptidoglycan (thinner for gram -)
What are the properties of flagella?
main way B move, aka H Ag target for antibodies, virulence factor, used in serological ID, is a PAMP
What are the properties of pili (fimbriae)?
attachment to tissues, virulence factor, anchored in membrane, sex pili (type IV secretion system) on gram -, antigenic variation to evade immune system, a PAMP
What are the properties of capsule or slime layer?
virulence factor, allow adherence to each other, biofilms and artificial surfaces, polysaccharide, K Ag in many Vi Ag in salmonella
What is a biofilm and what can it do?
plaque, increase gene transfer, increase antibiotic resistance, more virulent phenotypes, hard for antibiotic to get through, can be polymicrobial, can result in - blood cultures
What are the bacterial PAMPs?
LPS, peptidoglycan, flagellin, porins, lipoteichoic acids, lipoproteins and other membrane/cell wall/cytoplasm components
What is the make up of gram + cell wall organization?
polysaccharide chain linked by tetrapeptide chain and peptide cross bridge, teichoic acid and lipoteichoic acid anchored in wall and sticking out, pili, and cell wall specific Ag= peptidoglycan layer, cytoplasmic membrane under that made of phospholipids and proteins
What is the structure of peptidoglycan?
aka murein, polysaccharide chain, tetrapeptide side chains, peptide cross bridges (target of transpeptidase, penicillin binding protein), biologic activities- inflammation, adhesion antiphagocytic, somnolence, PAMP
What does teichoic acids cause in the host?
gram +, inflammation, adhesion, cation binding, biofilm formation, phage receptors, PAMPs
What are some key components of the outer membrane of gram - bacteria?
porins (trimer, PAMP), secretion systems (type III and IV), LPS (endotoxin), periplasmic space, and peptidoglycan (murein, PAMP)
How do the different secretion systems work?
III: syringe and needle, translocation of effector proteins (exotoxin) into eukaryotic cytoplasm (otherwise stuck in PP space); IV- conjugation, biofilm formation, adhesion
What are the features of LPS on gram - outer membranes?
lipid A is toxic portion (virulence factor), polysaccharide core, repeat unit P-O-P= O Ag in serotyping also for adherence (virulence factor)
What compounds are used to remove cell walls for different types of cells?
protoplasts (G+), Spheroblasts (G-), mycoplasma has no cell wall have to target protein synthesis
What are the cytoplasmic membrane functions?
active transport, electron transport, synthesis and export of cell wall components, secretion of enzymes, including exotoxins
What is an important factor in penicillin resistance in bacteria? is there a difference between Gram - and +?
periplasmic space allows for concentration of B-lactamase so more potent with Gram -, Gram + still secretes it but has to constantly produce it
What are the typical cytoplasmic contents of bacteria?
chromosome: circular, plasmid- extrachromosomal DNA-> virulence factor or AB resistance, spreads btwn B and viruses, can have multiple copies; ribosomes: 70s (30s + 50s), and inclusions
What is an endospore? Which type forms this?
protective function, gram positive, forms when nutrient levels drop so it can regerminate when there is a new nutrient source
What are the components of a spore? (outside in with function or make-up)
Exosporim, Coat (protein with disulfide bond, most of resistance), Outer membrane, cortex (peptidoglycan), inner membrane, core (dehydrated with enzymes and chromosome)
