Quiz 3 Flashcards
Aflatoxins (6)
Flat-ringed planar compounds that can intercalate between the bases of DNA & act as mutagens
Where are myxobacteria found? Gram positive or negative? Defining feature? (7A)
- Gram-negative bacteria found in high-organic soils and decomposing plant material
- Social bacteria
Myxobacteria shape (7A)
Rod-shaped with a flexible cell wall
Myxobacteria motility (7A)
- Do not use flagella
- Perform gliding motility that allows them to swarm on surfaces in a coordinated manner
- Travel in ripples
Myxobacteria life cycle (7A)
- Upon starvation, vegetative cells will aggregate into fruiting bodies, within which a subpopulation differentiates into stress-resistant myxospores
- When introduced to a new food source, the myxospores germinate & give rise to new cells which use gliding motility & divide via binary fission
Myxospores (7A)
-Some genera of myxobacteria will have myxospores containined in sacs called sporangioles borne on stalks formed by vegetative cells
Are Actinomycetes gram positive or negative? Aerobic or anaerobic? Defining feature? (7B)
- Aerobic, gram positive microbes
- Form branching filaments
Actinomycetes shape (7B)
- Appear to be intermediate between bacteria & fungi
- Resemble filamentous fungi with extensive, branching mycellium
- Some genera give rise to condidospores
Actinomycetes colonies (7B)
- Form small, compact, leathery colonies
- Usually consisting to two types of mycelia
- –i) Form a very fine vegetative/submerged mycellium that grows into the subsrate which feeds
- –ii) Form an aerial mycellium which is thicker and may give a powdery appearance as a result of condidospores
Streptomyces (7B)
- An important genera of Actinomycetes
- Soil-dwelling
- Major source of antibiotics
Photosynthesis (7C)
Capture light energy and convert it to chemical energy
Cyanobacteria (7C)
- A type of photosynthetic bacteria
- Performs oxygenic photosynthesis (provides oxygen)
- Use chlorophylls
Green and Purple Algae (7C)
- Types of photosynthetic bacteria
- Perform anoxygenic photosynthesis (do not provide oxygen) using other reduced compounds as sources of electrons
- Use bacteriochlorophylls
Accessory pigments (7C)
- Phycobiliproteins & carotenoids
- Absorb light energy and transfer it to the chlorophyll or bacteriochlorophyll
- Can protect the microorganism from intense sunlight
Green and purple sulfur bacteria (7C)
- Oxidize certain inorganic sulfur compounds during photosynthesis
- Obligate anaerobes – cannot tolerate any oxygen
- Found in aquatic sediments exposed to light
Green and purple non-sulfur bacteria (7C)
- Facultative aerobes – do not require oxygen for growth, but grow better in its presence
- Found in aquatic sediments exposed to light
Succession (7D)
How one group of organisms succeeds another as conditions are created which select for them
—Ex: Like in a Winogradsky column
What does a TTC Deep test for? What does TTC stand for? (8A)
- Triphenyl Tetrazolium Chloride
- Tests for motility
- No growth will occur if organism is obligate anaerobe
What does a TSI Slant test for? What does TSI stand for? (8A)
- Triple Sugar Iron Agar
- –Contains Lactose, Sucrose, and Glucose
- Tests for acid or alkaline
- –Yellow: Acid (fermentation)
- –Red: Alkaline (non-fermentation)
- Black color indicated H2S production
What does growing a microbe in Tryptone Broth indicate? What must you add after incubation to complete test? (8A)
-Must add Kovak’s Reagent to determine if Indole is produced
What does Bile Esculin Broth indicate? (8A)
- Contains bile salts, which inhibit Streptococcus from growing
- Tests ability to hydrolyze esculin to esculitin & glucose
What does MacConkey agar select for? What does it differentiate? (8A)
- Selectivity: Crystal violet inhibits gram positive growth
- Differentiable: Lactose with neutral red dye in media; Lactose fermenters appear pink, Nonfermentors are yellow or colorless
What does Ashby’s N-Free Agar select for? (8A)
-Selective for microorganisms able to fix atmospheric N2 for growth
What are the two non-selective types of media used in this lab? (8A)
i) TSA - Tryptic Soy Agar
ii) LB - Luria Bertani
What does CNA stand for? What does it select for? Differentiate for? (8A)
- Colistin-Nalidixic Acid Agar (with blood)
- Blocks gram negative organisms from growth – disrupts lipids and LPS in gram negative outer membrane
- –Note: Bacillus normally does not grow on CNA even though it is gram positive
- Differential: Blood detects hemolytic activity
Psuedomonas Enrichment Benzoate Medium (8A)
-Psuedomonas can convert hydroxybenzoate in the medium to Acetyl-CoA & Succinate, which can be used in the TCA cycle
What does PAF stand for What is it selective for? What does it differentiate? (8A)
- PAF: Psuedomonas Agar F
- Non-selective
- Differential: Color change to fluoresce in the presence of Pyoverdin
What does PAP stand for? What is in selective for? What does it differentiate? (8A)
- PAP: Psuedomonas Agar P
- Non-selective
- Differential: Color change to blue in presence of pyocyanin
What does MSA stand for? What is it selective for? What does it differentiate? (8A)
- MSA: Mannitol Salt Agar
- Selective: High salts selects for Staphylococcus
- Deifferential: Mannitol fermentation (yellow: acid fermentation)
Blood Agar selectivity and differentiability (8A)
- Non-selective
- Differential: Hemolysis
- Beta hemolysis: Complete (clear are around colonies)
- Alpha hemolysis: Partial, greenish
- Gamma hemolysis: No hemolysis
DNAse Test with Methyl Green (8A)
- Selective: Methyl green inhibits some gram positive bacteria
- Differential: Clearing indicated DNA hydrolysis / DNAse positive
Oxidase Test (8A)
- Tests for cytochrome oxidase
- Oxidation indicator produces purple color
Catalase Test (8A)
- Hydrogen peroxide detects presence of catalase
- –Bubble formation means catalase positive
