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[4]: 188 The overall shape of the colony may be characterized as circular, irregular, or punctiform (like pinpoints). The vertical growth or elevation of the colony, another identifying characteristic, is assessed by tilting the agar plate to the side and is denoted as flat, raised, convex, pulvinate (very convex), umbilicate (having a ...
Colony-forming units are used to quantify results in many microbiological plating and counting methods, including: The pour plate method wherein the sample is suspended in a Petri dish using molten agar cooled to approximately 40–45 °C (just above the point of solidification to minimize heat-induced cell death).
Colonies of Bacillus subtilis on a Petri dish can grow under controlled conditions. By varying agar concentration (which permits the control of the hardness of the medium), and the nutrient concentration, the response of the colony to external stresses can be studied. The different morphologies appear in the following growth conditions:
Blood agar plates (BAPs) contain mammalian blood (usually sheep or horse), typically at a 5–10% concentration. BAPs are enriched, and differential media is used to isolate fastidious organisms and detect hemolytic activity. β-Hemolytic activity will show lysis and complete digestion of red blood cell contents surrounding a colony.
An agar plate – an example of a bacterial growth medium*: Specifically, it is a streak plate; the orange lines and dots are formed by bacterial colonies.. A growth medium or culture medium is a solid, liquid, or semi-solid designed to support the growth of a population of microorganisms or cells via the process of cell proliferation [1] or small plants like the moss Physcomitrella patens. [2]
The colony-forming unit (CFU) is an appropriate description of the colony's origin. In plate counts, colonies are counted, but the count is usually recorded in CFU. Due to the fact that colonies growing on plates may begin as either a single cell or a cluster of cells, CFU allows for a correct description of the cell density.
Bacillus mycoides is a bacterium of the genus Bacillus.Like other Bacillus species, B. mycoides is Gram positive, rod-shaped, and forms spores. B. mycoides is distinguished from other Bacillus species by its unusual growth on agar plates, where it forms expansive hairy colonies with characteristic swirls.
It grows readily on nutrient agar, producing distinctive smooth low convex colonies with a characteristic striking dark violet metallic sheen (due to violacein production). [3] Some strains of the bacteria which do not produce this pigment have also been reported. [4] It has the ability to break down tarballs. [5]