An
agar plate is a sterile
Petri dishA petri dish is a shallow glass or plastic cylindrical lidded dish that biologists use to culture cells. It was named after German bacteriologist Julius Richard Petri, who invented it when working as an assistant to Robert Koch...
that contains a
growth mediumA growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or cells , or small plants like the moss Physcomitrella patens .There are different types of media for growing different types of cells....
(typically
agarAgar or agar agar is a gelatinous substance derived from seaweed. Historically and in a modern context, it is chiefly used as an ingredient in desserts throughout Japan, but in the past century has found extensive use as a solid substrate to contain culture medium for microbiological work...
plus nutrients) used to
cultureA microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory conditions. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested,...
microorganisms or small plants like the
mossMosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
Physcomitrella patensPhyscomitrella patens is a moss used as a model organism for studies on plant evolution, development and physiology.-Model organism:...
.
Selective growth compounds may also be added to the media, such as
antibioticIn common usage, an antibiotic is a substance or compound that kills or inhibits the growth of bacteria...
s.
Individual microorganisms placed on the plate will grow into individual
coloniesIn biology, a colony refers to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defences or the ability to attack bigger prey. Some insects live only in colonies...
, each a
cloneCloning in biology is the process of producing populations of genetically-identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or organisms...
genetically identical to the individual ancestor organism (except for the low, unavoidable rate of
mutationIn biology, a mutation is a randomly derived change to the nucleotide sequence of the genetic material of an organism.Mutations can be caused by copying errors in the genetic material during cell division, or by exposure to mutagens , or can be induced by the organism itself, by cellular processes...
).
An
agar plate is a sterile
Petri dishA petri dish is a shallow glass or plastic cylindrical lidded dish that biologists use to culture cells. It was named after German bacteriologist Julius Richard Petri, who invented it when working as an assistant to Robert Koch...
that contains a
growth mediumA growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or cells , or small plants like the moss Physcomitrella patens .There are different types of media for growing different types of cells....
(typically
agarAgar or agar agar is a gelatinous substance derived from seaweed. Historically and in a modern context, it is chiefly used as an ingredient in desserts throughout Japan, but in the past century has found extensive use as a solid substrate to contain culture medium for microbiological work...
plus nutrients) used to
cultureA microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory conditions. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested,...
microorganisms or small plants like the
mossMosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
Physcomitrella patensPhyscomitrella patens is a moss used as a model organism for studies on plant evolution, development and physiology.-Model organism:...
.
Selective growth compounds may also be added to the media, such as
antibioticIn common usage, an antibiotic is a substance or compound that kills or inhibits the growth of bacteria...
s.
Individual microorganisms placed on the plate will grow into individual
coloniesIn biology, a colony refers to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defences or the ability to attack bigger prey. Some insects live only in colonies...
, each a
cloneCloning in biology is the process of producing populations of genetically-identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or organisms...
genetically identical to the individual ancestor organism (except for the low, unavoidable rate of
mutationIn biology, a mutation is a randomly derived change to the nucleotide sequence of the genetic material of an organism.Mutations can be caused by copying errors in the genetic material during cell division, or by exposure to mutagens , or can be induced by the organism itself, by cellular processes...
). Thus, the plate can be used either to estimate the concentration of organisms in a
liquid cultureA microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory conditions. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested,...
or a suitable dilution of that culture using a
colony counterA colony counter is an instrument used to count colonies of bacteria or other microorganisms growing on an agar plate. Early counters were merely lighted surfaces on which the plate was placed, with the colonies marked off with a felt-tipped pen on the outer surface of the plate while the operator...
, or to generate genetically pure cultures from a mixed culture of genetically different organisms, using a technique known as "
streakingStreaking is a technique used in microbiology to isolate a pure strain from a single species of microorganism, often bacteria. A microbiological culture can be grown so that the organism can be identified, studied, or tested. A sterile cotton swab or inoculation loop is sterilized and dipped in a...
". In this technique, a drop of the culture on the end of a thin,
sterileSterilization refers to any process that effectively kills or eliminates transmissible agents from a surface, equipment, article of food or medication, or biological culture medium. Sterilization does not, however, remove prions...
loop of wire, sometimes known as an inoculator, is streaked across the surface of the agar leaving organisms behind, a higher number at the beginning of the streak and a lower number at the end. At some point during a successful "streak", the number of organisms deposited will be such that distinct individual colonies will grow in that area which may be removed for further culturing, using another sterile loop.
Types of agar plates
Like other
growth mediaA growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or cells , or small plants like the moss Physcomitrella patens .There are different types of media for growing different types of cells....
, the formulations of agar used in plates may be classified as either "defined" or "undefined"; defined medium is synthesized from individual chemicals required by the organism so that the exact molecular composition is known, whereas undefined medium is made from natural products such as
yeast extractYeast extract is the common name for various forms of processed yeast products that are used as food additives or flavourings. They are often used in the same way that monosodium glutamate is used, and, like MSG, often contain free glutamic acid. The texture ranges from liquid to a light paste...
, where the precise composition is unknown.
Agar plates may be formulated as either
permissive, with the intent of allowing the growth of whatever organisms are present, or
restrictive or
selective, with the intent of only allowing growth a particular subset of those organisms. This may take the form of a nutritional requirement, for instance providing a particular compound such as
lactoseLactose is a sugar that is found most notably in milk. Lactose makes up around 2–8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey...
as the only source of
carbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
and thereby selecting only organisms which can
metabolizeMetabolism is the set of chemical reactions that occur in living organisms to maintain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories. Catabolism breaks down organic matter,...
that compound, or by including a particular antibiotic or other substance in order to select only organisms which are
resistantAntibiotic resistance is the ability of a microorganism to withstand the effects of antibiotics. It is a specific type of drug resistance. Antibiotic resistance evolves via natural selection acting upon random mutation, but it can also be engineered by applying an evolutionary stress on a population...
to that substance. This correlates to some degree with defined and undefined media; undefined media, made from natural products and containing an unknown combination of very many organic molecules, is typically more permissive in terms of supplying the needs of a wider variety of organisms, while defined media can be precisely tailored to select organisms with specific properties.
Agar plates may also be
indicator plates, in which the organisms are not selected on the basis of growth, but are instead distinguished by a color change in some colonies, typically caused by the action of an
enzymeEnzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, called the products. Almost all processes in a biological cell need enzymes to occur at...
on some compound added to the media.
Some commonly used agar plate types are:
Blood agar types
- Contains mammalian blood (usually sheep or horse), typically at a concentration of 5–10%. BAP are an enriched, differential media used to isolate fastidious
A growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or cells , or small plants like the moss Physcomitrella patens .There are different types of media for growing different types of cells....
organisms and detect hemolyticHemolysis is the breakdown of red blood cells. The ability of bacterial colonies to induce hemolysis when grown on blood agar is used to classify certain microorganisms. This is a particularly useful in classifying streptococcal species...
activity. β-hemolytic activity will show complete lysis of red blood cells surrounding colony. Examples include Streptococcus haemolyticus. α-hemolysis will only partially lyse hemoglobin and will appear green. An example of this would be Streptococcus viridans. γ-hemolysis (or non-hemolytic) is the term referring to a lack of hemolytic activity.
Contains meat extract,
tryptoneTryptone is the assortment of peptides formed by the digestion of casein by the protease trypsin.Tryptone is commonly used in microbiology to produce Lysogeny broth for the growth of E. coli and other microorganisms...
,
sodium chlorideSodium chloride, also known as salt, common salt, table salt, or halite, is an ionic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
, and agar.
- Chocolate agar
Chocolate agar - is a non-selective, enriched growth medium. It is a variant of the blood agar plate. It contains red blood cells, which have been lysed by heating very slowly to 56 °C. Chocolate agar is used for growing fastidious respiratory bacteria, such as Haemophilus influenzae...
(CHOC)
- A type of blood agar plate in which the blood cells have been lysed
Lysis refers to the death of a cell by breaking of the cellular membrane, causing the contents to spill out, often by viral, enzymic or osmotic mechanisms that compromise its integrity...
by heating the cells to 56 °C. Chocolate agar is used for growing fastidious (fussy) respiratory bacteria, such as Haemophilus influenzaeHaemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile Gram-negative rod-shaped bacterium first described in 1892 by Richard Pfeiffer during an influenza pandemic. A member of the Pasteurellaceae family, it is generally aerobic, but can grow as a...
. No chocolateChocolate comprises a number of raw and processed foods produced from the seed of the tropical cacao tree. Cacao has been cultivated for at least three millennia in Mexico, Central and South America, with its earliest documented use around 1100 BC...
is actually contained in the plate; it is named for the coloration only.
- Thayer-Martin agar
Thayer-Martin agar is a Mueller-Hinton agar with 5% chocolate sheep blood and antibiotics. It is used for culturing and primarily isolating pathogenic Neisseria bacteria, including Neisseria gonorrhoeae and Neisseria meningitidis, as the medium inhibits the growth of most other microorganisms...
(TM)
- Chocolate agar designed to isolate Neisseria gonorrhoeae
Neisseria gonorrhoeae, also known as Gonococci , or Gonococcus , is a species of Gram-negative coffee bean-shaped diplococci bacteria responsible for the sexually transmitted disease gonorrhea....
.
- TCBS (thiosulfate
Thiosulfate , sometimes spelled Thiosulphate, is an oxyanion of sulfur produced by the reaction of sulfite ions with elemental sulfur in boiling water. Thiosulfate occurs naturally in hot springs and geysers, and is produced by certain biochemical processes...
citrateA citrate can refer either to the conjugate base of citric acid, , or to the esters of citric acid...
bile saltsBile acids are steroid acids found predominantly in the bile of mammals. Bile salts are bile acids conjugated to glycine or taurine. In humans, taurocholic acid and glycocholic acid represent approximately eighty percent of all bile salts. The two major bile acids are cholic acid, and...
sucroseSucrose, commonly called table sugar, is a moosaccharide of glucose and fructose with the molecular formula C12H22O11. This white, odorless, crystalline powder has a pleasing, sweet taste. It is best known for its role in human nutrition...
)-enriched agar enhances growth of Vibrio choleraeVibrio cholerae is a motile gram negative curved-rod shaped bacterium with a polar flagellum that causes cholera in humans. V. cholerae and other species of the genus Vibrio belong to the gamma subdivision of the Proteobacteria. There are two major strains of V. cholerae, classic and El Tor,...
General bacterial media
- Bile esculin agar
Bile Esculin Agar is a selective differential agar used to isolate and identify members of the genus Enterococcus, also known as "group D streptococci".-Composition and process:...
(BEA)
- BEA is used for the isolation of Enterococci
Enterococcus is a genus of lactic acid bacteria of the phylum Firmicutes. Members of this genus were classified as Group D Streptococcus until 1984 when genomic DNA analysis indicated that a separate genus classification would be appropriate....
as well as Group D StreptococciStreptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name — from Greek στρεπτος streptos, meaning...
- CLED agar
CLED agar is a valuable non-inhibitory growth medium used in the isolation and differentiation of urinary organisms. Being electrolyte deficient, it prevents the swarming of Proteus species. Cysteine promotes the formation of cysteine-dependent dwarf colonies...
(CysteineCysteine is an α-amino acid with the chemical formula HO
2CCHCH
2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is nonpolar and thus cysteine is usually classified as...
LactoseLactose is a sugar that is found most notably in milk. Lactose makes up around 2–8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey...
Electrolyte Deficient agar)
- CLED agar is used to isolate and differentiate urinary tract bacteria, since it inhibits Proteus
Proteus is a genus of Gram-negative Proteobacteria.-Clinical significance:Three species—P. vulgaris, P. mirabilis, and P. penneri—are opportunistic human pathogens. Proteus includes pathogens responsible for many human urinary tract infections. Proteus mirabilis causes wound and...
species swarming and can differentiate between lactose fermenters and non-fermenters.
- Hektoen enteric agar
Hektoen enteric agar is a selective and differential agar primarily used to recover Salmonella and Shigella from patient specimens. HE contains indicators of lactose fermentation and H2S production; as well as inhibitors to prevent the growth of gram positive bacteria...
(HEA)
- HE agar is designed to isolate and recover fecal bacteria belonging to the Enterobacteriaceae
The Enterobacteriaceae are a large family of bacteria, including many of the more familiar pathogens, such as Salmonella and Escherichia coli...
family. HE is particularly useful in isolating SalmonellaSalmonella is a genus of rod-shaped, Gram-negative, non-spore forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which project in all directions...
and ShigellaShigella is a genus of Gram-negative, non-spore forming rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella cause disease in primates, but not in other mammals. It is only naturally found in humans and apes. During infection,...
.
- Lysogeny Broth
Lysogeny broth , a nutritionally rich medium, is primarily used for the growth of bacteria. It is also known as Luria broth or Luria-Bertani broth, though both of these names are incorrect...
(LB)
- McConkey agar (MAC)
- A selective and differential media used to differentiate between Gram negative bacteria while inhibiting the growth of Gram positive bacteria. The addition of bile salts and crystal violet to the agar inhibits the growth of most Gram positive bacteria, making MacConkey agar selective. Lactose and neutral red
Neutral Red is a eurhodin dye used for staining in histology. It stains lysosomes red . It is used as a general stain in histology, as a counterstain in combination with other dyes, and for many staining methods. Together with Janus Green B it is used to stain embryonal tissues and supravital...
are added to differentiate the lactose fermenters, which form pink colonies, from lactose nonfermenters that form clear colonies. An alternative media, eosin methylene blueEosin methylene blue is a selective stain for Gram-negative bacteria. It is a blend of two stains, eosin and methylene blue in the ratio of 6:1...
(EMB) serves a similar purpose.
- Mannitol salt agar
Mannitol salt agar or MSA is a commonly used growth medium in microbiology.It contains a high concentration of salt , making it selective for Staphylococci since this level of NaCl is inhibitory to most other bacteria. It is also a differential medium, containing mannitol and the indicator phenol...
(MSA)
- MSA is also a selective and differential media. The mannitol
Mannitol is an organic compound with the formula . This polyol is used as an osmotic diuretic agent and a weak renal vasodilator...
indicates organisms that ferment mannitol: mannitol fermentation produces lactic acidLactic acid , also known as milk acid, is a chemical compound that plays a role in several biochemical processes. It was first isolated in 1780 by a Swedish chemist, Carl Wilhelm Scheele, and is a carboxylic acid with a chemical formula of C
3H
6O
3...
, lowering the pH and turning the plate yellow. The salt is to select for halophileHalophiles are extremophile organisms that thrive in environments with very high concentrations of salt. The name comes from Greek for "salt-loving". While the term is perhaps most often applied to some halophiles classified into the Archaea domain, there are also bacterial halophiles and some...
s; organisms that cannot withstand a high salt content will be unable to grow well.
- Mueller-Hinton agar
Müller-Hinton agar is an microbiological growth medium that is commonly used for antibiotic susceptibility testing. It is also used to isolate and maintain Neisseria and Moraxella species.It typically contains :*30.0% beef infusion...
(MHA)
- MHA contains beef infusion, peptone, and starch
Starch or amylum is a polysaccharide carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds.Starch is produced by all green plants as an energy store and is a major food source for humans....
and is used primarily for antibiotic susceptibility testing. It can be in a form of blood agar.
- Nutrient agar
Nutrient agar is a microbiological growth medium commonly used for the routine cultivation of non-fastidious bacteria.Nutrient agar typically contains :*0.5 % peptone*0.3 % beef extract*1.5 % agar*pH adjusted to neutral at 25 °C....
- Nutrient agar is usually used for growth of non-fastidious organisms and observation of pigment production. It is safe to use in school science laboratories because it does not selectively grow pathogen
A pathogen , infectious agent, or germ, is a biological agent that causes disease or illness to its host....
ic bacteria.
- Önöz agar allows more rapid bacteriological diagnosis as Salmonella
Salmonella is a genus of rod-shaped, Gram-negative, non-spore forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which project in all directions...
and ShigellaShigella is a genus of Gram-negative, non-spore forming rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella cause disease in primates, but not in other mammals. It is only naturally found in humans and apes. During infection,...
colonies can be clearly and reliably differentiated from other EnterobacteriaceaeThe Enterobacteriaceae are a large family of bacteria, including many of the more familiar pathogens, such as Salmonella and Escherichia coli...
. The yields of Salmonella from stool samples obtained, when using this medium, are higher than those obtained with LEIFSON Agar or Salmonella–Shigella agar (SSA).
- Phenylethyl alcohol agar (PEA)
- PEA selects for Staphylococcus
Staphylococcus is a genus of Gram-positive bacteria. Under the microscope they appear round , and form in grape-like clusters....
species while inhibiting Gram-negativeGram-negative bacteria are those bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
bacilli (e.g. Escherichia coliEscherichia coli , is a Gram negative bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E...
, ShigellaShigella is a genus of Gram-negative, non-spore forming rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella cause disease in primates, but not in other mammals. It is only naturally found in humans and apes. During infection,...
, ProteusProteus is a genus of Gram-negative Proteobacteria.-Clinical significance:Three species—P. vulgaris, P. mirabilis, and P. penneri—are opportunistic human pathogens. Proteus includes pathogens responsible for many human urinary tract infections. Proteus mirabilis causes wound and...
, etc.).
- R2A Agar
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....
(R2A)
- A non-specific agar that imitates the medium of water. Used for water analysis.
- Tryptic (Trypticase) Soy Agar
Trypticase soy agar is a bacterial growth medium.The medium contains enzymatic digests of casein and soybean meal which provides amino acids and other nitrogenous substances making it a nutritious medium for a variety of organisms. Dextrose is the energy source. Sodium chloride maintains the...
(TSA)
- TSA is a general purpose media produced via enzymatic digestion of soybean
The soybean or soya bean is a species of legume native to East Asia. The plant is classed as an oilseed rather than a pulse. It is an annual plant that has been used in China for 5,000 years to primarily add nitrogen into the soil as part of crop rotation...
meal and caseinCasein is the predominant phosphoprotein that accounts for nearly 80% of proteins in cow milk and cheese. Milk-clotting proteases act on the soluble portion of the caseins, K-Casein, thus originating an unstable micellar state that results in clot formation. When coagulated with rennin, casein is...
. TSA is frequently the base media of other agar types; for example, blood agar plates are made by enriching TSA plates with blood (see above).
- TSA plates support growth of many semi-fastidious bacteria, including some species of Brucella
Brucella is a genus of Gram-negative bacteria. They are small , non-motile, non-encapsulated coccobacilli....
, CorynebacteriumCorynebacterium is a genus of Gram-positive rod-shaped bacteria. They are widely distributed in nature and are mostly innocuous. Some are useful in industrial settings such as C. glutamicum. Others cause human disease such as C...
, Listeria, NeisseriaThe Neisseria are a large family of commensal bacteria that colonize the mucosal surfaces of many animals. Of the eleven species that colonize humans, only two are pathogens. N. meningitidis and N. gonorrhoeae often cause asymptomatic infections, a commensal-like behavior...
, and VibrioVibrio is a genus of Gram-negative bacteria possessing a curved rod shape. Typically found in saltwater, Vibrio are facultative anaerobes that test positive for oxidase and do not form spores. All members of the genus are motile and have polar flagella with sheaths...
.
- Xylose
Xylose lysine deoxycholate agar is a selective growth medium used in the isolation of Salmonella and Shigella species from clinical samples and from food. It has a pH of approximately 7.4, leaving it with a bright pink or red appearance due to the indicator phenol red. Sugar fermentation lowers...
-LysineLysine is an α-amino acid with the chemical formula HO
2CCH
4NH
2. This amino acid is an essential amino acid, which means that humans cannot synthesize it. Its codons are AAA and AAG.Lysine is a base, as are arginine and histidine...
-Deoxycholate agar (XLD)
- XLD is used for the culture of stool
A stool can refer to:*A type of chair without back and arm rests** In West Africa, a throne** A bar stool ** A footstool* A flush toilet, in some dialects* Feces:* A living stump capable of producing sprouts or cuttings...
samples and contains two indicators. It is formulated to inhibit Gram-positive bacteria, while the growth of Gram-negative bacilliBacilli refers to a taxonomic class of bacteria. It includes two orders, Bacillales and Lactobacillales, which contain several well-known pathogens like Bacillus anthracis .- Ambiguity :...
is encouraged. The colonies of lactose fermenters appear yellow.
- It is also used to culture possible Salmonella
Salmonella is a genus of rod-shaped, Gram-negative, non-spore forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which project in all directions...
that may be present in a food sample. Salmonella colonies will show a black halo on XLD.
- Cetrimide agar
Cetrimide agar is a type of agar used for the selective isolation of the gram-negative bacteria, Pseudomonas aeruginosa. As the name suggests, it contains cetrimide, which is the selective agent against alternate microbial flora...
- Cetrimide agar is a type of agar used for the selective isolation of the gram-negative bacteria, Pseudomonas aeruginosa
Pseudomonas aeruginosa is a common bacterium which can cause disease in animals and humans. It is found in soil, water, skin flora and most man-made environments throughout the world. It thrives not only in normal atmospheres, but also with little oxygen, and has thus colonised many natural and...
.
- Tinsdale agar contains potassium tellurite, which can isolate Corynebacterium diphteriae.
Fungal media
- Sabouraud
Raymond Sabouraud was a French physician born in Nantes. He specialized in dermatology and mycology, and was also an accomplished painter and sculptor....
agar
- Sabouraud agar is used to culture fungi and has a low pH
pH is a measure of the acidity or basicity of a solution. It is defined as the cologarithm of the activity of dissolved hydrogen ions . Hydrogen ion activity coefficients cannot be measured experimentally, so they are based on theoretical calculations...
that inhibits the growth of most bacteria; it also contains the antibiotic gentamicinGentamicin is an aminoglycoside antibiotic, used to treat many types of bacterial infections, particularly those caused by Gram-negative bacteria...
to specifically inhibit the growth of Gram-negativeGram-negative bacteria are those bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
bacteria.
- Specific for the culturing of slime mould
Slime mold is a broad term describing fungi-like organisms that use spores to reproduce. They were formerly classified as fungi, but are no longer considered part of this group....
s (which are not fungi).
- Potato dextrose agar
Potato dextrose agar and potato dextrose broth are common microbiological media made from potato infusion, and dextrose...
- PDA is used to culture certain types of fungi.
- Malt extract agar has a high content of peptone and is acidic. It is essentially used in the isolation of fungal microorganisms.
Moss media
- Knop agar is used to culture axenically protonema
A protonema is a thread-like chain of cells that forms the earliest stage of a bryophyte life cycle. When a moss or liverwort first grows from the spore, it grows as a protonema which develops into a leafy gametophore.Moss spores germinate to form an alga-like filamentous structure called the...
and whole mossMosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
plants, e.g. those of Physcomitrella patensPhyscomitrella patens is a moss used as a model organism for studies on plant evolution, development and physiology.-Model organism:...
, a model organismA model organism is a species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms...
.
See also
- Growth medium
A growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or cells , or small plants like the moss Physcomitrella patens .There are different types of media for growing different types of cells....
- MRS agar
Often abbreviated to MRS, this type of bacterial growth medium is so-named by its inventors: de Man, Rogosa and Sharpe. Developed in 1960, this medium was designed to favour the luxuriant growth of Lactobacilli for lab study...
- Petri dish
A petri dish is a shallow glass or plastic cylindrical lidded dish that biologists use to culture cells. It was named after German bacteriologist Julius Richard Petri, who invented it when working as an assistant to Robert Koch...
- R2a agar
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....
- Replica plating
In molecular biology and microbiology, replica plating is a technique in which one or more secondary Petri plates containing different solid selective growth media are inoculated with the same colonies of microorganisms from a primary plate , reproducing the original spatial...
- Viral plaque
A viral plaque is a visible structure formed within a cell culture, such as bacterial cultures within some nutrient medium . The bacteriophage viruses replicate and spread, thus generating regions of cell destructions known as plaques....
External links