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Craigie Tube
The Cragie tube or Craigie tube is a method used in microbiologyTextbook of Microbiology by Ananthanarayan and Panikar, for determining bacterial motility. __NOTOC__ Technique A hollow tube with some culture medium is placed in semi-solid agar inside a bottle. A sample of the bacterium to be tested is inoculated into the medium in the hollow tube and the setup is incubated at 37 °C overnight. Observation On examining the areas where bacterial growth has occurred there are several observations to be made: *the colonies of the non-motile bacteria Non-motile bacteria are bacteria species that lack the ability and structures that would allow them to propel themselves, under their own power, through their environment. When non-motile bacteria are cultured in a stab tube, they only grow along ... remain confined within the tube at the site of inoculation *the motile bacteria swim out from the bottom of the tube and colonize the surrounding medium as well Confirmation may be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbiology
Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology, and parasitology. Eukaryotic microorganisms possess membrane-bound organelles and include fungi and protists, whereas prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea. Microbiologists traditionally relied on culture, staining, and microscopy. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using current means. Microbiologists often rely on molecular biology tools such as DNA sequence based identification, for example the 16S rRNA gene sequence used for bacteria identification. Viruses have been variably classified as organisms, as they have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Motility
Bacterial motility is the ability of bacteria to move independently using metabolic energy. Most motility mechanisms which evolved among bacteria also evolved in parallel among the archaea. Most rod-shaped bacteria can move using their own power, which allows colonization of new environments and discovery of new resources for survival. Bacterial movement depends not only on the characteristics of the medium, but also on the use of different appendages to propel. Swarming and swimming movements are both powered by rotating flagella. Whereas swarming is a multicellular 2D movement over a surface and requires the presence of surfactants, swimming is movement of individual cells in liquid environments. Other types of movement occurring on solid surfaces include twitching, gliding and sliding, which are all independent of flagella. Twitching depends on the extension, attachment to a surface, and retraction of type IV pili which pull the cell forwards in a manner similar to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Culture Media
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 or small plants like the moss ''Physcomitrella patens''. Different types of media are used for growing different types of cells. The two major types of growth media are those used for cell culture, which use specific cell types derived from plants or animals, and those used for microbiological culture, which are used for growing microorganisms such as bacteria or fungi. The most common growth media for microorganisms are nutrient broths and agar plates; specialized media are sometimes required for microorganism and cell culture growth. Some organisms, termed fastidious organisms, require specialized environments due to complex nutritional requirements. Viruses, for example, are obligate intracellular parasites and require a growth medium containing living cells. Types The most common growth media fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agar
Agar ( or ), or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from ogonori (''Gracilaria'') and "tengusa" (''Gelidiaceae''). As found in nature, agar is a mixture of two components, the linear polysaccharide agarose and a heterogeneous mixture of smaller molecules called agaropectin. It forms the supporting structure in the cell walls of certain species of algae and is released on boiling. These algae are known as agarophytes, belonging to the Rhodophyta (red algae) phylum. The processing of food-grade agar removes the agaropectin, and the commercial product is essentially pure agarose. Agar has been used as an ingredient in desserts throughout Asia and also as a solid substrate to contain culture media for microbiological work. Agar can be used as a laxative; an appetite suppressant; a vegan substitute for gelatin; a thickener for soups; in fruit preserves, ice cream, and other desser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-motile Bacteria
Non-motile bacteria are bacteria species that lack the ability and structures that would allow them to propel themselves, under their own power, through their environment. When non-motile bacteria are cultured in a stab tube, they only grow along the stab line. If the bacteria are mobile, the line will appear diffuse and extend into the medium. The cell structures that provide the ability for locomotion are the cilia and flagella. Coliform and Streptococci are examples of non-motile bacteria as are ''Klebsiella pneumoniae'', and ''Yersinia pestis''. Motility is one characteristic used in the identification of bacteria and evidence of possessing structures: peritrichous flagella, polar flagella and/or a combination of both. Though the lack of motility might be regarded a disadvantage, some non-motile bacteria possess structures that allow their attachment to eukaryotic cells, like GI mucousal cells. Vancomycin resistant Enterococcus spp. are non-motile while vancomycin susceptib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inoculation
Inoculation is the act of implanting a pathogen or other microorganism. It may refer to methods of artificially inducing immunity against various infectious diseases, or it may be used to describe the spreading of disease, as in "self-inoculation," the spreading of disease from one part of the body to another, or even to the spreading of bacteria in a Petri dish for culturing purposes. The terms "inoculation", "vaccination", and "immunization" are often used synonymously, but there are some important differences among them. Inoculation is the act of implanting a disease inside a person or animal, vaccination is the act of implanting or giving someone a vaccine specifically, and immunization is what happens to the immune system as a result. Terminology Until the early 1800s inoculation referred only to variolation (from the Latin word ''variola'' = smallpox), the predecessor to the smallpox vaccine. The smallpox vaccine, introduced by Edward Jenner in 1796, was called cowpox inoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subculture (biology)
In biology, a subculture is either a new cell culture or a microbiological culture made by transferring some or all cells from a previous culture to fresh growth medium. This action is called subculturing or passaging the cells. Subculturing is used to prolong the lifespan and/or increase the number of cells or microorganisms in the culture. Role Cell lines and microorganisms cannot be held in culture indefinitely due to the gradual rise in toxic metabolites, use of nutrients and increase in cell number due to growth. Once nutrients are depleted and levels of toxic byproducts increase, the bacteria in the overnight culture enter the stationary phase, where proliferation is greatly reduced or ceased (the cell density value plateaus). When microorganisms from this overnight culture are transferred into the fresh media, nutrients trigger the growth of the microorganism and it goes through the lag phase, a period of slow growth and adaptation to the new environment, and then the log p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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