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Mannitol motility medium is a bacterial growth medium used to detect the ability of bacteria to ferment mannite and produce nitrogen gas; and to indicate the motility of the organism. [1]
The typical medium is composed of: [1]
When inoculated with a sample organism and allowed to incubate, the medium will change color from red to yellow to indicate that the mannite has been fermented. The presence of bubbles in the medium indicates the presence of gaseous nitrogen, produced by the organism. The pattern of color change (localized along the inoculation site vs. dispersed throughout the medium) indicates the motility of the organism. [1]
The following known results can be used to validate the proper composition of the medium: [1]
An agar plate is a Petri dish that contains a growth medium solidified with agar, used to culture microorganisms. Sometimes selective compounds are added to influence growth, such as antibiotics.
Proteus vulgaris is a rod-shaped, nitrate-reducing, indole-positive and catalase-positive, hydrogen sulfide-producing, Gram-negative bacterium that inhabits the intestinal tracts of humans and animals. It can be found in soil, water, and fecal matter. It is grouped with the Morganellaceae and is an opportunistic pathogen of humans. It is known to cause wound infections and other species of its genera are known to cause urinary tract infections.
Malolactic conversion is a process in winemaking in which tart-tasting malic acid, naturally present in grape must, is converted to softer-tasting lactic acid. Malolactic fermentation is most often performed as a secondary fermentation shortly after the end of the primary fermentation, but can sometimes run concurrently with it. The process is standard for most red wine production and common for some white grape varieties such as Chardonnay, where it can impart a "buttery" flavor from diacetyl, a byproduct of the reaction.
Coliform bacteria are defined as either motile or non-motile Gram-negative non-spore forming Bacilli that possess β-galactosidase to produce acids and gases under their optimal growth temperature of 35-37°C. They can be aerobes or facultative aerobes, and are a commonly used indicator of low sanitary quality of foods, milk, and water. Coliforms can be found in the aquatic environment, in soil and on vegetation; they are universally present in large numbers in the feces of warm-blooded animals as they are known to inhabit the gastrointestinal system. While coliform bacteria are not normally causes of serious illness, they are easy to culture, and their presence is used to infer that other pathogenic organisms of fecal origin may be present in a sample, or that said sample is not safe to consume. Such pathogens include disease-causing bacteria, viruses, or protozoa and many multicellular parasites.
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.
MacConkey agar is a selective and differential culture medium for bacteria. It is designed to selectively isolate Gram-negative and enteric bacteria and differentiate them based on lactose fermentation. Lactose fermenters turn red or pink on MacConkey agar, and nonfermenters do not change color. The media inhibits growth of Gram-positive organisms with crystal violet and bile salts, allowing for the selection and isolation of gram-negative bacteria. The media detects lactose fermentation by enteric bacteria with the pH indicator neutral red.
Shigella dysenteriae is a species of the rod-shaped bacterial genus Shigella. Shigella species can cause shigellosis. Shigellae are Gram-negative, non-spore-forming, facultatively anaerobic, nonmotile bacteria. S. dysenteriae has the ability to invade and replicate in various species of epithelial cells and enterocytes.
Industrial fermentation is the intentional use of fermentation in manufacturing processes. In addition to the mass production of fermented foods and drinks, industrial fermentation has widespread applications in chemical industry. Commodity chemicals, such as acetic acid, citric acid, and ethanol are made by fermentation. Moreover, nearly all commercially produced industrial enzymes, such as lipase, invertase and rennet, are made by fermentation with genetically modified microbes. In some cases, production of biomass itself is the objective, as is the case for single-cell proteins, baker's yeast, and starter cultures for lactic acid bacteria used in cheesemaking.
Mannitol salt agar or MSA is a commonly used selective and differential growth medium in microbiology. It encourages the growth of a group of certain bacteria while inhibiting the growth of others. It contains a high concentration of salt (NaCl) which is inhibitory to most bacteria - making MSA selective against most Gram-negative and selective for some Gram-positive bacteria that tolerate high salt concentrations. It is also a differential medium for mannitol-fermenting staphylococci, containing the sugar alcohol mannitol and the indicator phenol red, a pH indicator for detecting acid produced by mannitol-fermenting staphylococci. Staphylococcus aureus produces yellow colonies with yellow zones, whereas other coagulase-negative staphylococci produce small pink or red colonies with no colour change to the medium. If an organism can ferment mannitol, an acidic byproduct is formed that causes the phenol red in the agar to turn yellow. It is used for the selective isolation of presumptive pathogenic (pp) Staphylococcus species.
In microbiology, the phenotypic testing of mycobacteria uses a number of methods. The most-commonly used phenotypic tests to identify and distinguish Mycobacterium strains and species from each other are described below.
Lentilactobacillus buchneri is a gram-positive, non-spore forming, anaerobic, rod prokaryote. L. buchneri is a heterofermentative bacteria that produces lactic acid and acetic acid during fermentation. It is used as a bacterial inoculant to improve the aerobic stability of silage. These bacteria are inoculated and used for preventing heating and spoilage after exposure to air.
Glucose phosphate broth is used to perform methyl red (MR) test and Voges–Proskauer test (VP).
Yeast assimilable nitrogen or YAN is the combination of free amino nitrogen (FAN), ammonia (NH3) and ammonium (NH4+) that is available for a yeast, e.g. the wine yeast Saccharomyces cerevisiae, to use during fermentation. Outside of the fermentable sugars glucose and fructose, nitrogen is the most important nutrient needed to carry out a successful fermentation that doesn't end prior to the intended point of dryness or sees the development of off-odors and related wine faults. To this extent winemakers will often supplement the available YAN resources with nitrogen additives such as diammonium phosphate (DAP).
Actinoplanes italicus is distinguished by the cherry-red color of its vegetative mycelium, and by the production of soluble pigments. It is also known to produce sporangia when cultured on starch or skim milk agar. Very few strains have been found and cultured, thus A. italicus is relatively uncharacterized.
In microbiology, the term isolation refers to the separation of a strain from a natural, mixed population of living microbes, as present in the environment, for example in water or soil, or from living beings with skin flora, oral flora or gut flora, in order to identify the microbe(s) of interest. Historically, the laboratory techniques of isolation first developed in the field of bacteriology and parasitology, before those in virology during the 20th century.
Azotobacter salinestris is a Gram-negative, nitrogen-fixing bacterium; its specific name, salinestris, comes from the Latin words salinus meaning saline and estris which means "living in". It can be found living in soil or marine habitats as single cells or in chains of six to eight cells. This organism is motile at younger stages, but loses its flagella at older stages. This species is known for its potential use in bioremediation.
Diagnostic microbiology is the study of microbial identification. Since the discovery of the germ theory of disease, scientists have been finding ways to harvest specific organisms. Using methods such as differential media or genome sequencing, physicians and scientists can observe novel functions in organisms for more effective and accurate diagnosis of organisms. Methods used in diagnostic microbiology are often used to take advantage of a particular difference in organisms and attain information about what species it can be identified as, which is often through a reference of previous studies. New studies provide information that others can reference so that scientists can attain a basic understanding of the organism they are examining.
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.
Propionispira raffinosivorans is a motile, obligate anaerobic, gram-negative bacteria. It was originally isolated from spoiled beer and believed to have some causative effect in beer spoilage. Since then, it has been taxonomically reclassified and proven to play a role in anaerobic beer spoilage, because of its production of acids, such as acetic and propionic acid, during fermentation
In microbiology, colonial morphology refers to the visual appearance of bacterial or fungal colonies on an agar plate. Examining colonial morphology is the first step in the identification of an unknown microbe. The systematic assessment of the colonies' appearance, focusing on aspects like size, shape, colour, opacity, and consistency, provides clues to the identity of the organism, allowing microbiologists to select appropriate tests to provide a definitive identification.