Agar, 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 phylum. The processing of food-grade agar removes the agaropectin, and the commercial product is essentially pure agarose.
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.
Bacteriological water analysis is a method of analysing water to estimate the numbers of bacteria present and, if needed, to find out what sort of bacteria they are. It represents one aspect of water quality. It is a microbiological analytical procedure which uses samples of water and from these samples determines the concentration of bacteria. It is then possible to draw inferences about the suitability of the water for use from these concentrations. This process is used, for example, to routinely confirm that water is safe for human consumption or that bathing and recreational waters are safe to use.
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.
Lysogeny broth (LB) is a nutritionally rich medium primarily used for the growth of bacteria. Its creator, Giuseppe Bertani, intended LB to stand for lysogeny broth, but LB has also come to colloquially mean Luria broth, Lennox broth, life broth or Luria–Bertani medium. The formula of the LB medium was published in 1951 in the first paper of Bertani on lysogeny. In this article he described the modified single-burst experiment and the isolation of the phages P1, P2, and P3. He had developed the LB medium to optimize Shigella growth and plaque formation.
Potato dextrose agar and potato dextrose broth are common microbiological growth media made from potato infusion and dextrose. Potato dextrose agar is the most widely used medium for growing fungi and bacteria.
Plate Count Agar (PCA), also called Standard Methods Agar (SMA), is a microbiological growth medium commonly used to assess or to monitor "total" or viable bacterial growth of a sample. PCA is not a selective medium.
R2A agar is a culture medium developed to study bacteria which normally inhabit potable water. These bacteria tend to be slow-growing species and would quickly be suppressed by faster-growing species on a richer culture medium.
De Man, Rogosa and Sharpe agar, often abbreviated to MRS, is a selective culture medium designed to favour the luxuriant growth of Lactobacilli for lab study. Developed in 1960, this medium was named for its inventors, Johannes Cornelis de Man, Morrison Rogosa, and Margaret Elisabeth Sharpe. It contains sodium acetate, which suppresses the growth of many competing bacteria. This medium has a clear brown colour.
Brain heart infusion (BHI) is a growth medium for growing microorganisms. It is a nutrient-rich medium, and can therefore be used to culture a variety of fastidious organisms. In particular, it has been used to culture streptococci, pneumococci and meningococci, which can be otherwise challenging to grow. BHI is made by combining an infusion from boiled bovine or porcine heart and brain with a variety of other nutrients. BHI broth is often used in food safety, water safety, and antibiotic sensitivity tests.
YM Agar and Broth, is a selective growth medium with low pH useful for cultivating yeasts, molds, or other acid-tolerant or acidophilic organisms, while deterring growth of most bacteria and other acid intolerant organisms. It is malt extract medium modified by the addition of yeast extract and peptone.
Nutrient agar is a general purpose liquid medium supporting growth of a wide range of non-fastidious organisms. It typically contains (mass/volume):
Sabouraud agar or Sabouraud dextrose agar (SDA) is a type of agar growth medium containing peptones. It is used to cultivate dermatophytes and other types of fungi, and can also grow filamentous bacteria such as Nocardia. It has utility for research and clinical care.
Tryptic soy broth or Trypticase soy broth is used in microbiology laboratories as a culture broth to grow aerobic bacteria. It is a complex, general purpose medium that is routinely used to grow certain pathogenic bacteria, which tend to have high nutritional requirements. Its agar counterpart is tryptic soy agar (TSA). One of the components of Tryptic soy broth is PhytoneArchived 2014-08-22 at the Wayback Machine, which is an enzymatic digest of soybean meal.
Oxidative/fermentation glucose test is a biological technique. It was developed in 1953 by Hugh and Leifson to be utilized in microbiology to determine the way a microorganism metabolizes a carbohydrate such as glucose (dextrose). OF-glucose deeps contain glucose as a carbohydrate, peptones, bromothymol blue indicator for Hugh-Leifson's OF medium or phenol red for King's OF medium, and 0.5% agar.
This bacterial growth medium was developed in 1971 for Lactococcus species isolated from milk products. It was originally called M16 medium, but in 1975 Terzaghi and Sandine added disodium-β-glycerophosphate to the medium as a buffer, and named the new growth medium M17 medium. It was later found that the addition of disodium-β-glycerophosphate inhibits the growth of many Lactobacillus species.
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.
C.D.V. agar is a nutrient medium prepared using Cicer arietinum, Daucus carota (carrot) and Vigna radiata by Vinay J. Rao and Keshava Murthy P. at Surana College, Bangalore, India under the guidance of their botany lecturers, B. R. Chandrashekarappa, Sharada H.C., and with the aid of their classmates from Vijaya College, Bangalore.
The NYC medium or GC medium agar is used for isolating Gonococci.
BAF agar or biotin-aneurin-folic acid agar is a type of agar growth medium containing peptones. It is used to grow cultures of mycorrhizal fungi. It was first described by A.J.P. Oort in Nutritional requirements of Lactarius species and cultural characters in relation to taxonomy in 1981. The acidic pH (5.8-6.3) of BAF agar inhibits bacterial growth.
