In microbiology, a cell spreader or plate spreader is a tool used to smoothly spread cells and bacteria on a culture plate, such as a petri dish.
Cell spreaders can be made from glass, plastic, or metal, and come in various shapes.
A Drigalski spatula is a cell spreader consisting of a cylindrical rod or wire bent in the shape of a triangle with a handle. [1] [2] [3] Another variant is a rod bent in L-shape. [4] Extrusion molded versions can be T-shaped. [5]
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Drop cells or bacteria at the center of the dish. Researchers can then place the spreader on top of the dish and, without applying much pressure, swirl the spreader around on the dish to evenly distribute the cells or bacteria. [6]
Before using a cell spreader, if the spreader is made from glass or metal, researchers must sterilize the spreader by submerging it in alcohol or ethanol and later burning the alcohol off by placing the spreader in a Bunsen burner flame to eliminate microorganisms. [7]
After each use, the spreader should be placed in alcohol or ethanol to keep it clean and prevent it from being contaminated with unwanted particles.
Disposable cell spreaders made of plastic are usually not subject to sterilization, but discarded.
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.
A Petri dish is a shallow transparent lidded dish that biologists use to hold growth medium in which cells can be cultured, originally, cells of bacteria, fungi and small mosses. The container is named after its inventor, German bacteriologist Julius Richard Petri. It is the most common type of culture plate. The Petri dish is one of the most common items in biology laboratories and has entered popular culture. The term is sometimes written in lower case, especially in non-technical literature.
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.
Replica plating is a microbiological technique in which one or more secondary Petri plates containing different solid (agar-based) selective growth media are inoculated with the same colonies of microorganisms from a primary plate, reproducing the original spatial pattern of colonies. The technique involves pressing a velveteen-covered disk, and then imprinting secondary plates with cells in colonies removed from the original plate by the material. Generally, large numbers of colonies are replica plated due to the difficulty in streaking each out individually onto a separate plate.
A spatula is a broad, flat, flexible blade used to mix, spread and lift material including foods, drugs, plaster and paints.
An inoculation loop is a simple tool used mainly by microbiologists to pick up and transfer a small sample of microorganisms called inoculum from a microbial culture, e.g. for streaking on a culture plate. This process is called inoculation.
A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. Microbial cultures are foundational and basic diagnostic methods used as research tools in molecular biology.
The Ziehl-Neelsen stain, also known as the acid-fast stain, is a bacteriological staining technique used in cytopathology and microbiology to identify acid-fast bacteria under microscopy, particularly members of the Mycobacterium genus. This staining method was initially introduced by Paul Ehrlich (1854–1915) and subsequently modified by the German bacteriologists Franz Ziehl (1859–1926) and Friedrich Neelsen (1854–1898) during the late 19th century.
A blood culture is a medical laboratory test used to detect bacteria or fungi in a person's blood. Under normal conditions, the blood does not contain microorganisms: their presence can indicate a bloodstream infection such as bacteremia or fungemia, which in severe cases may result in sepsis. By culturing the blood, microbes can be identified and tested for resistance to antimicrobial drugs, which allows clinicians to provide an effective treatment.
Julius Richard Petri was a German microbiologist who is generally credited with inventing the device known as the Petri dish, which is named after him, while working as assistant to bacteriologist Robert Koch.
The oxidase test is used to determine whether an organism possesses the cytochrome c oxidase enzyme. The test is used as an aid for the differentiation of Neisseria, Moraxella, Campylobacter and Pasteurella species. It is also used to differentiate pseudomonads from related species.
In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria. Samples can then be taken from the resulting colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested.
A policeman is a hand-held flexible natural-rubber or plastic scraper. The common type of it is attached to a glass rod and used in chemical laboratories to transfer residues of precipitate or solid on glass surfaces when performing gravimetric analysis. This equipment works well under gentle, delicate and precise requirement. A policeman also comes in various sizes, shapes, and types. Some of them come in one-piece flexible plastic version and some in stainless. The origin of the policeman and its name cannot be identified for sure but some clues led back to the 19th century from German chemist Carl Remigius Fresenius.
The 3M Petrifilm plate is an all-in-one plating system made by the Food Safety Division of the 3M Company. They are heavily used in many microbiology-related industries and fields to culture various micro-organisms and are meant to be a more efficient method for detection and enumeration compared to conventional plating techniques. A majority of its use is for the testing of foodstuffs.
Instruments used specially in microbiology include:
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.
An inoculation needle is a laboratory equipment used in the field of microbiology to transfer and inoculate living microorganisms. It is one of the most commonly implicated biological laboratory tools and can be disposable or re-usable. A standard reusable inoculation needle is made from nichrome or platinum wire affixed to a metallic handle. A disposable inoculation needle is often made from plastic resin. The base of the needle is dulled, resulting in a blunted end.
A Drigalski spatula is a type of cell spreader consisting of a cylindrical rod or wire, usually of metal or glass, bent in the shape of a triangle with a handle.
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.
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.