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How Does a Colony Develop in Microbiology?

In microbiology, colonies are collections of a single type of microorganism. Microorganisms divide and create new versions of themselves. These organisms usually remain together, though some forces can carry organisms to other locations where they can form other colonies. Organisms that form colonies include bacteria, fungi and protozoa. Bacterial cultures contain a variety of bacteria, and pure colonies of bacteria are very rare. They usually only form under artificial conditions.

Carried Spores
- New colonies start when part of a colony breaks off and wind carries that part to a new surface. When the surface is conducive to growth, the organism grows and reproduces. Some organisms, such as fungi, produce structures designed to send spores through the air.
Visibility
- While microorganisms are usually not visible by the naked eye, colonies become visible. When the individual organisms produce chemicals that create pigments, the surface colonized by these microorganisms will have this color. The colonies can look smooth and shiny or can have a rough and dry-looking surface. The borders can be jagged or very smooth, depending on the species. The growth of the bacteria depends mostly on the availability of nutrients. Semi-solid surfaces have nutrients that diffuse more than in solid mediums. Therefore, some organisms grow in wavy patterns when on semi-solid surfaces.
Movement
- The microorganisms sometimes release chemicals that communicate messages to other microorganisms, letting them know to migrate to a particular direction that has more food. Bacterial colonies mostly move using flagella, which are structures that extend from the cell surface. Helical bacteria have axial filaments that allow the cell to rotate in a spiral fashion. Some bacteria produce slime that helps them glide across surfaces. In liquid environments, bacteria usually have more motion. These bacteria are only constrained in movement by the other bacteria. These bacteria will sometimes move in organized ways to further expand the colony.
Cultures
- Scientists sometimes create their own colonies to study a particular type of microorganism using a culture medium. This is a medium conducive to bacterial growth. The scientists inoculate the medium with the bacteria and then incubate the organisms under conditions ideal for their growth. The medium can be synthetic or non-synthetic. It can also be solid or a broth. Solid mediums allow scientists to study how the bacteria grows. Non-synthetic mediums have one component that isn't consistent, purified or categorized. These components are often proteins from various organisms. Technicians use premixed mediums prepared by manufacturers that are ready for inoculation. Some mediums are enriched to help improve the growth condition. Some mediums deliberately suppress the growth of some microorganisms while encouraging the growth of others.

Nature