Antonio e Biagio e Cesare Arrigo Petri dish

Petri dish at the Pacific Northwest National Laboratory

A Petri dish (alternatively known as a Petri plate or cell-culture dish) is a shallow transparent lidded dish that biologists use to hold growth medium in which

cells Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

can be cultured,R. C. Dubey (2014): ''A Textbook Of Biotechnology For Class-XI'', 4th edition, p. 469. originally, cells of

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...

and small mosses. The container is named after its inventor, German

bacteriologist A bacteriologist is a microbiologist, or similarly trained professional, in bacteriology -- a subdivision of microbiology that studies bacteria, typically pathogenic ones. Bacteriologists are interested in studying and learning about bacteria, ...

Julius Richard Petri. It is the most common type of

culture plate In microbiology, a culture plate is a low flat-bottomed laboratory container for growing a layer of organisms such as bacteria, molds, and cells on a thin layer of nutrient medium. The most common types are the petri dish and multiwell plates. ...

. The Petri dish is one of the most common items in biology laboratories and has entered

popular culture Popular culture (also called mass culture or pop culture) is generally recognized by members of a society as a set of practices, beliefs, artistic output (also known as, popular art or mass art) and objects that are dominant or prevalent in a ...

. The term is sometimes written in lower case, especially in non-technical literature. What was later called Petri dish was originally developed by German physician Robert Koch in his private laboratory in 1881, as a precursor method. Petri, as assistant to Koch, at Berlin University made the final modifications in 1887 as used today.

Penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from '' Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum usin ...

, the first antibiotic, was discovered in 1929 when Alexander Fleming noticed that mold that had contaminated a

l culture in a Petri dish had killed the bacteria all around it.

Features and variants

Petri dishes are usually cylindrical, mostly with diameters ranging from , and a height to diameter ratio ranging from 1:10 to 1:4. Squarish versions are also available.(2019):
Item 1219C98: Square Petri dish w/ grid
. Thomas Scientific online catalog. Accessed on 2019-10-25.(2019):
Product 11708573: Gosselin Square Petri Dish
. Fischer Scientific online catalog. Accessed on 2019-10-25. Petri dishes were traditionally reusable and made of

glass Glass is a non- crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenchin ...

; often of heat-resistant borosilicate glass for proper

sterilization Sterilization may refer to: * Sterilization (microbiology), killing or inactivation of micro-organisms * Soil steam sterilization, a farming technique that sterilizes soil with steam in open fields or greenhouses * Sterilization (medicine) rende ...

at 120–160

°C The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The d ...

.(2019):
Product 4909050: PYREX reusable Petri dishes: complete
. Fischer Scientific online catalog. Accessed on 2019-10-25. Since the 1960s,

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adapta ...

dishes, usually disposable, are also common.(2019):
Product BP94S01: Corning 100 x 15mm Polystyrene Petri Dishes
. Fischer Scientific online catalog. Accessed on 2019-10-25. The dishes are often covered with a shallow transparent lid, resembling a slightly wider version of the dish itself. The lids of glass dishes are usually loose-fitting. Plastic dishes may have close-fitting covers that delay the drying of the contents.(2019):
Item 09-720-500: Fisherbrand disposable Petri dishes
. Fischer Scientific online catalog. Accessed on 2019-10-25. Alternatively, some glass or plastic versions may have small holes around the rim, or ribs on the underside of the cover, to allow for air flow over the culture and prevent water condensation.(2019):
Item SB93102: Corning 100x15mm Petri dish with three vents
. Fischer Scientific online catalog. Accessed on 2019-10-25. Some Petri dishes, especially plastic ones, usually feature rings and/or slots on their lids and bases so that they are less prone to sliding off one another when stacked or sticking to a smooth surface by suction. Small dishes may have a protruding base that can be secured on a

microscope A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisi ...

stage for direct examination(2019):
Product PD1504700 MilliporeSigma PetriSlide for contamination analysis
. Fischer Scientific online catalog. Accessed on 2019-10-25. Some versions may have grids printed on the bottom to help in measuring the density of cultures.(2019):
Item 41044: Petri dishes made of glass with grid and cover
. Assistent (Karl Hecht) online catalog. Accessed on 2019-10-25 A microplate is a single container with an array of flat-bottomed cavities, each being essentially a small Petri dish. It makes it possible to inoculate and grow dozens or hundreds of independent cultures of dozens of samples at the same time. Besides being much cheaper and convenient than separate dishes, the microplate is also more amenable to automated handling and inspection.

History

The Petri dish was developed by German physician Julius Richard Petri (after whom the name is given) while working as an assistant to Robert Koch at Berlin University. Petri did not invent the culture dish himself; rather, it was a modified version of Koch's invention which used an agar medium that was developed by Walther Hesse. Koch had published a precursor dish in a booklet in 1881 titled "''Zur Untersuchung von Pathogenen Organismen''" (''Methods for the Study of Pathogenic Organisms''), which has been known as the "Bible of Bacteriology." He described a new bacterial culture method that used a glass slide with agar and a container (basically a Petri dish, a circular glass dish of 20 × 5 cm with matching lid) which he called ''feuchte Kammer'' ("moist chamber"). A bacterial culture was spread on the glass slide, then placed in the moist chamber with a small wet paper. Bacterial growth was easily visible. Koch publicly demonstrated his plating method at the Seventh International Medical Congress in London in August 1881. There, Louis Pasteur exclaimed, ''"C'est un grand progrès, Monsieur''!" ("What a great progress, Sir!") It was using this method that Koch discovered important pathogens of

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, ...

('' Mycobacterium tuberculosis''),

anthrax Anthrax is an infection caused by the bacterium '' Bacillus anthracis''. It can occur in four forms: skin, lungs, intestinal, and injection. Symptom onset occurs between one day and more than two months after the infection is contracted. The s ...

('' Bacillus anthracis''), and cholera ('' Vibrio cholerae''). For his research on tuberculosis, he was awarded the

Nobel Prize in Physiology or Medicine The Nobel Prize in Physiology or Medicine is awarded yearly by the Nobel Assembly at the Karolinska Institute for outstanding discoveries in physiology or medicine. The Nobel Prize is not a single prize, but five separate prizes that, accordi ...

in 1905. His students also made important discoveries. Friedrich Loeffler discovered the bacteria of glanders (''

Burkholderia mallei ''Burkholderia mallei'' is a Gram-negative, bipolar, aerobic bacterium, a human and animal pathogen of genus ''Burkholderia'' causing glanders; the Latin name of this disease (''malleus'') gave its name to the species causing it. It is closel ...

'') in 1882 and

diphtheria Diphtheria is an infection caused by the bacterium '' Corynebacterium diphtheriae''. Most infections are asymptomatic or have a mild clinical course, but in some outbreaks more than 10% of those diagnosed with the disease may die. Signs and s ...

('' Corynebacterium diphtheriae'') in 1884; and

Georg Theodor August Gaffky Georg Theodor August Gaffky (17 February 1850 – 23 September 1918) was a Hanover-born bacteriologist best known for identifying bacillus salmonella typhi as the cause of typhoid disease in 1884. Early life and career Gaffky's parents were the ...

, the bacterium of typhoid ('' Salmonella enterica'') in 1884. Petri made changes in how the circular dish was used. It is often asserted that Petri developed a new culture plate, but this is incorrect. Instead of using a separate glass slide or plate on which culture media were placed, Petri directly placed media into the glass dish, eliminating unnecessary steps such as transferring the culture media, using the wet paper, and reducing the chance of contamination. He published the improved method in 1887 as "''Eine kleine Modification des Koch’schen Plattenverfahrens''" ("A minor modification of the plating technique of Koch"). Although it could have been named "Koch dish," the final method was given an eponymous name Petri dish.

Uses

Microbiology

Petri dishes are widely used in biology to cultivate microorganisms such as

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constit ...

s, and molds. It is most suited for organisms that thrive on a solid or semisolid surface. The

culture medium 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''. Differ ...

is often an agar plate, a layer a few mm thick of agar or agarose

gel A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still di ...

containing whatever nutrients the organism requires (such as

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

, salts,

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may o ...

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha ...

s) and other desired ingredients (such as dyes,

indicators Indicator may refer to: Biology * Environmental indicator of environmental health (pressures, conditions and responses) * Ecological indicator of ecosystem health (ecological processes) * Health indicator, which is used to describe the health o ...

, and

medicinal drug A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and r ...

s). The agar and other ingredients are dissolved in warm water and poured into the dish and left to cool down. Once the medium solidifies, a sample of the organism is inoculated ("plated"). The dishes are then left undisturbed for hours or days while the organism grows, possibly in an

incubator An incubator is anything that performs or facilitates various forms of incubation, and may refer to: Biology and medicine * Incubator (culture), a device used to grow and maintain microbiological cultures or cell cultures * Incubator (egg), a de ...

. They are usually covered, or placed upside-down, to lessen the risk of contamination from airborne

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

Virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsk ...

or phage cultures require that a population of bacteria be grown in the dish first, which then becomes the culture medium for the viral inoculum. While Petri dishes are widespread in microbiological research, smaller dishes tend to be used for large-scale studies in which growing cells in Petri dishes can be relatively expensive and labor-intensive.

Contamination detection and mapping

Petri dishes can be used to visualize the location of contamination on surfaces, such as kitchen counters and utensils, clothing, food preparation equipment, or animal and human skin.Sonja Bäumel (2009):
Oversized petri dish
. Culture of microorganisms from the artist's skin pressed onto a body-size culture plate, photographed over the span of 44 days. Part of her ''(In)visible membrane'' project. Wageningen, Germany. Accessed on 2019-10-25. For this application, the Petri dishes may be filled so that the culture medium protrudes slightly above the edges of the dish to make it easier to take samples on hard objects. Shallow Petri dishes prepared in this way are called Replicate Organism Detection And Counting (RODAC) plates and are available commercially.Scott Sutton (2007): "Microbial Surface Monitoring", p. 78. Chapter 5 of Anne Marie Dixon (ed.), ''Environmental Monitoring for Cleanrooms and Controlled Environments''. Géraldine Daneau, Elie Nduwamahoro, Kristina Fissette, Patrick Rüdelsheim, Dick van Soolingen, Bouke C. de Jong, Leen Rigouts (2016): "Use of RODAC plates to measure containment of Mycobacterium tuberculosis in a Class IIB biosafety cabinet during routine operations." ''International Journal of Mycobacteriology'', volume 5, issue 2, pp. 148–54.

Cell culture

Petri dishes are also used for cell cultivation of isolated cells from

eukaryotic Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

organisms, such as in

immunodiffusion Immunodiffusion is a diagnostic test which involves diffusion through a substance such as 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, prim ...

studies, on solid agar or in a liquid medium.

Botany and agriculture

Petri dishes may be used to observe the early stages of plant germination, and to grow plants asexually from isolated cells.

Entomology

Petri dishes may be convenient enclosures to study the behavior of insects and other small animals.

Chemistry

Due to their large open surface, Petri dishes are effective containers to evaporate

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

s and dry out precipitates, either at room temperature or in ovens and desiccators.

Sample storage and display

Petri dishes also make convenient temporary storage for samples, especially liquid, granular, or powdered ones, and small objects such as insects or seeds. Their transparency and flat profile allows the contents to be inspected with the naked eye,

magnifying glass A magnifying glass is a convex lens that is used to produce a magnified image of an object. The lens is usually mounted in a frame with a handle. A magnifying glass can be used to focus light, such as to concentrate the sun's radiation to c ...

, or low-power microscope without removing the lid.

In popular culture

The Petri dish is one of a small number of laboratory equipment items whose name entered popular culture. It is often used metaphorically, e.g. for a contained community that is being studied as if they were microorganisms in a biology experiment, or an environment where original ideas and enterprises may flourish.Gary Singer (2018):
Sonder, in the City
. Quote: ''As a native New Yorker, I tend to think of this city as a giant petri dish, in which some of the greatest breakthroughs, inventions, and audacious ideas have been nurtured to fruition.'' In Angela Dews (ed.) ''Still, in the City: Creating Peace of Mind in the Midst of Urban Chaos'', p. 40. Isabel Slone (2018):
What Does the Mall Goth Nostalgia Trend Really Mean?
. Quote: ''"mall goth" was a style of dress that combined the hallmarks of punk, goth and metal subcultures and thrived like bacteria in the petri dish of the early 2000s.'' Online article in the Fashion Magazine website, May 22, 2018. Accessed on 2019-10-25.

Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, ...

has a Petri dish emoji, "🧫", which has the code point U+1F9EB ( HTML entity "🧫" or "🧫",

UTF-8 UTF-8 is a variable-length character encoding used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode'' (or ''Universal Coded Character Set'') ''Transformation Format 8-bit''. UTF-8 is capable of e ...

"0xF0 0x9F 0xA7 0xAB").(2019):
Emoji List, v12.1
. Webpage at the Unicode Consortium website. Accessed on 2019-10-25.

References

External links

{{DEFAULTSORT:Petri Dish Laboratory glassware Microbiology equipment German inventions 1887 in science 1887 in Germany