The Actinomycetales is an

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

Actinomycetota The ''Actinomycetota'' (or ''Actinobacteria'') are a phylum of all gram-positive bacteria. They can be terrestrial or aquatic. They are of great economic importance to humans because agriculture and forests depend on their contributions to s ...

. A member of the order is often called an actinomycete. Actinomycetales are generally gram-positive and anaerobic and have mycelia in a filamentous and branching growth pattern. Some actinomycetes can form rod- or coccoid-shaped forms, while others can form spores on aerial

hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

. Actinomycetales bacteria can be infected by

bacteriophage A bacteriophage (), also known informally as a ''phage'' (), is a duplodnaviria virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν ('), meaning "to devour". Bac ...

s, which are called actinophages. Actinomycetales can range from harmless bacteria to pathogens with resistance to antibiotics.

Reproduction

Actinomycetales have 2 main forms of reproduction:

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, ...

formation and hyphae fragmentation. During reproduction, Actinomycetales can form

conidiophores A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to ...

, sporangiospores, and oidiospores. In reproducing through hyphae fragmentation, the hyphae formed by Actinomycetales can be a fifth to half the size of fungal hyphae, and bear long spore chains.

Presence and associations

Actinomycetales can be found mostly in soil and decaying organic matter, as well as in living organisms such as humans and animals. They form symbiotic

nitrogen fixing Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmo ...

associations with over 200 species of plants, and can also serve as growth promoting or biocontrol agents, or cause disease in some species of plants. Actinomycetales can be found in the human urogenital tract as well as in the

digestive system The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller compone ...

including the mouth, throat, and

gastrointestinal The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

tract in the form of Helicobacter without causing disease in the host. They also have wide medicinal and

botanical Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...

applications, and are used as a source of many

antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and preventio ...

and

pesticides Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and la ...

Antimicrobial properties

Many species of Actinomycetes produce antimicrobial compounds under certain conditions and growth media.

Streptomycin Streptomycin is an antibiotic medication used to treat a number of bacterial infections, including tuberculosis, ''Mycobacterium avium'' complex, endocarditis, brucellosis, ''Burkholderia'' infection, plague, tularemia, and rat bite fever. F ...

, actinomycin, and streptothricin are all medically important antibiotics isolated from Actinomycetes bacteria. Almost two-thirds of the natural antimicrobial drug compounds used currently are produced by different species of Actinomycetes.

References

{{Taxonbar, from=Q343452 Bacteria orders