Jeproday Flashcards
This group of organisms is defined as gram-negative rods that ferment lactose with the production of acid and gas within 48 hours at 37°C.
Coliforms
This is responsible for the formation of tumors or crown galls in plants
Agrobacterium tumefaciens carrying Ti plasmid.
In which species of Streptococcus would you expect to see beta hemolysis?
S. Pyogens
Name two endospore forming genera as well as their oxygen requirements.
Clostridium: obligate anaerobe
Bacillus: obligate aerobe or Facultative anaerobe.
Name the genera of bacteria that you would expect to see from the following procedures:
Heated soil sample on Czapek’s agar
Unseated soil sample on Czapek)s agar
Heated: Bacillus and Clostridium
Unseated: bacillus, clostridium, streptomyces, and others.
What is the difference between antibody and antigen?
Antibody: produced by the immune system, recognizes and binds to foreign antigen.
Antigen: a substance recognized by antibodies.
Draw on the board, the pathway that sulfonamides inhibit and explain the mechanism of action.
They inhibit PABA (makes folate in bacteria but humans don’t have it) ex. of selective toxicity through competitive inhibition. They are bacteriostatic, meaning they inhibit the cells but don’t kill them unlike antibodies which are bactericidal.
Think inhibits folate which is required to make Coenzyme F (participates in biosynthesis)
Describe the Kirby Bauer disk diffusion test. Does this allow you to differentiate between bacteriostatic and bactericidal antibodies?
The Kirby Bauer test: you placed antibiotic disks on a lot of bacteria and look for zones of clearing after incubation. No this will not allow you to distinguish between bacteriostatic and bactericidal.
What is the difference between Agglutination and Immunoprecipitation?
Agglutination: clumping due to cross-linking of antigen and antibody.
Immunoprecipitation: the formation of an insoluble protein complex when antibodies recognize an appropriate antigen.
How does antigen antibody binding form an insoluble lattice that precipitates?
Antibodies are bivalent, whereas antigens are polyvalent. This means that an antibody combined to epitopes on separate antigens and cross-link them to form a lattice.
Explain with EMB agar is both differential and selective:
Selective: presence of dyes, select for gram-negative rods
Differential: lactose ferments appear purple.
In what type of bacteria would you typically expect a positive catalse test?
aerobes and facultative anaerobes.
A tube of glucose peptone broth was inoculated with a loop of organisms and incubated for 36 to 48 hours. Following incubation 12 drops of VP ration a and four drop of VP raging B were added. What molecule is being tested for and what metabolic pathway is it associated with?
The presence of acetone due to the butanediol fermentation pathway of glucose.
What two organisms covered in lab exhibit different phenotypes when grown on different media describe both media and appearance.
Streptococcus Salivarius: production of capsule on TSY+sucrose, no capsule on TSY
Streptomyces: on Czapek’s agar it forms aerial hyphae and appears as typical bull’s eye morphology, on TSY appears as flat white colonies,
Describe the difference between a prophage and a lysogen.
Prophage: the bacteria phage genome that has integrated into the host genome.
Lysogen: a bacterium that contains a prophase in its genome.
