Term
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Definition
- appendages of bacterial cellular membranes
- neither pilli nor flagellum
- contain cytosol
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Term
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Definition
forms exactly midway between the
two cell poles during cell division |
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Term
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Definition
| a dormant, tough, and temporarily non-reproductive structure produced by certain bacteria |
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Term
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Definition
| structure capable of giving rise to a new bacterium |
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Term
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Definition
| the process of forming a bacterial endospore |
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Term
| spore acid-soluble proteins (SASPs) |
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Definition
| These are special proteins accumulated inside bacterial endospores; some are storage proteins degraded upon germination, others bind and protect spore DNA |
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Term
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Definition
| major constituent of the spore core |
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Term
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Definition
| The outer layer of the wall of a spore |
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Term
| Petroff-Hausser counting chamber |
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Definition
a method used to estimate the number of bacteria on a plate with a grid
- Advantages: quick, direct, can be linked to computer-assisted microscopy and image analysis
- Disadvantage: counts both living and dead cells, cell density must exceed ~ 106cells per ml
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Term
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Definition
measurement of light scatter
can be used as a method of estimating number of bacteria in a sample |
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Term
review the spore-forming Bacillus, Paenibacillus, and Clostridium species discussed in class: Paenibacillus
papilliae, Bacillus thuringiensis, |
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Definition
| see diagrams in the notes |
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Term
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Definition
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Term
| Bacillus and Paenibacillus characteristics |
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Definition
Rod shaped cells
Many produce antibiotics (examples: bacitracin, polymyxin, gramicidin)
B. thuringiensis
B. subtilis
B. anthracis |
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Term
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Definition
- rods
- Have no respiratory chain – energy from anaerobic fermentation
- Are strict anaerobes
- Some are beneficial (ferment sugars to produce solvents), while others are pathogens
- C. perfringens – pathogen causing gas gangrene and food poisoning
- C. tetani – causes tetanus
- C. botulinum – botulism
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Term
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Definition
| pathogen causing gas gangrene and food poisoning |
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Term
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Definition
| produces two equal products from bacterial division |
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Term
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Definition
unequal products of cell division
ex. Pirellula, Blastobacter |
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Term
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Definition
- unequal products
- progeny cell buds from a hyphae (extension of cell membrane)
- ex. hyphomicrobium, rhodomicrobium, pidomicrobium
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Term
| cell division of stalked organsim |
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Definition
- unequal products
- usually a flagullated bacterium is produced from an elongated stalked cell
- ex. Caulobacter
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Term
| polar growth without differentiation of cell size |
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Definition
- new cell arises from on pole of the parent cell
- unequal products
- ex. rhodopseudomonas, nitrobacter, methylosinus
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Term
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Definition
| https://angel.msu.edu/section/content/default.asp?WCI=pgDisplay&WCU=CRSCNT&ENTRY_ID=6FA3E46798544AEEAC031473CD0F53F3 |
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Term
| what is the structure of Streptomyces? |
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Definition
| a branching filamentous bacterium that produces spores by a distinct mechanism |
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Term
| Viable cell count by plating |
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Definition
- serial dilutions of culture
- transfer diluted samples to plate and incubate
- count colonies
- plate count x dilution factor = cells (colony forming units) per mililiter of original sample
- Advantages: very sensitive, only counts viable (culturable) cells
- Disadvantage: requires much preparation of
media, tubes, plates & pipettes; must use a wide range of dilutions; takes time to incubate before
obtaining results
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Term
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Definition
- Used mainly in water analysis
- water is filtered through a membrane filter
- membrane filter is incubated in an appropriate medium
- colonies are counted
- Advantages: very sensitive, only measures viable
(culturable) cells; can handle large sample sizes; requires less preparation than viable plate count
methods
- Disadvatages: incubation takes time before results are obtained, must use large range of dilutions
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Term
| Indirect Measurement by Turbidity |
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Definition
- Light passed through a bacterial suspension will scatter – less light will exit the sample than is entering the sample
- Thus, the loss of light energy (optical density) can be measured and indirectly quantitate cell numbers
- Is only accurate in a range in which the cell number is proportional to the optical density
- Advantages: quick, easy
- Disadvantages: requires preparation of a standard
curve, insensitive below 107 cells/ml, measures total (not viable) cell density
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Term
| why is standard curve needed for turbidity measurements of cell numbers? |
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Definition
| you need a standard curve with known concentrations that are associated with an optical density value in order to estimate the actual cell density of your sample |
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Term
| how many prokaryotic cells are estimated to be on earth? |
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Definition
- 4-6 x 1030 cells
- 92-94% of all prokaryotes live in the oceanic and terrestrial subsurface – below 0.1 meter
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