BioScience Dictionary

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Found Culture 86 times.

Displaying results 1 to 10.

1. Absorbance (optical density)
This is a measure of the amount of light absorbed by a suspension of bacterial cells or a solution of an organic molecule; it is measured by a colorimeter or spectrophotometer . Absorbance values are used to plot the growth of bacteria in suspension culture s and to gauge the purity and concentration of molecules (such as proteins) in solution. Absorbance is defined as a logarithmic function of the percent transmission of a wavelength of light through a liquid.

2. Acceleration phase
A period of increasing growth before the log phase in a culture of microbes. After the culture is started on a medium, at first there is no growth (the lag phase), and then the microbes start to gradually grow (acceleration phase) until they reach a constant maximum rate of growth (log phase).

3. Acclimatization (adaptation)
The physiological process through which an organism grows accustomed to a new environment. In microbial cultures, this can involve enzymatic changes that allow it to use an new nutrient source for energy.

4. Active biomass
The amount of a given culture that is actively growing.

5. Agar
This gelatinous material, an extract from red algae (mainly Gelidium and Gracilaria species), is most frequently used as a culture medium, especially for bacteria. It is also used as a thickener in foods, but humans can't digest it.

6. Agriculture
The science of raising plants and/or animals for food, clothing, or other useful products.

7. Agrochemical
Term for any artificially-produced chemical (such as a feed additives, pharmaceutical, fertilizer or pesticide ) used in agriculture to improve crop or livestock production.

8. Amniocentesis
A technique for testing the genetic health of a fetus by inserting a needle through the mother's abdominal wall into the uterus and extracting a small amount of the amniotic fluid, the fluid that surrounds the fetus. Sloughed-off fetal cells ( fibroblast s) found in this fluid are then cultured and their DNA examined for defects. This procedure is done in the second trimester, and because of the time needed to do the culture, results aren't generally available until after the 20th week of pregnancy.

9. Amplified Fragment Length Polymorphism (AFLP)
Invented by KeyGene, a Dutch biotech company based in Wageningen, Holland The technique is now merchandised under licence agreement by Perkin Elmer. Selected markers are amplified in a PCR , which makes AFLP an easy and fast tool for strain identification in agriculture , botany , microbiology and animal breeding.

10. Anchorage dependence
The phenomena that many mammalian cells won't culture properly unless they're grown in single layers of cells anchored to glass or plastic substrate s. This makes it difficult to culture such cells on a large scale. Only transformed cell s, hybridoma s and hematopoietic cells are easily grown in suspension cultures, which are preferred because they're easier to maintain.

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