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Types of Actinobacteria


Actinobacteria are a group of Gram-positive bacteria with high guanine and cytosine content in their DNA, which can be in their terrestrial or aquatic environment. Although they are unicellular like bacteria, they do not have separate cell walls but produce a thinner mycelium without septa. It includes the most common types of soil, freshwater and marine types that play an important role in the degradation of organic materials such as actinobacteria, cellulose and chitin. Thus, it plays a vital role in organic matter transformation and carbon cycle and replenishes the nutrients in it. It is an important part of soil and humus formation. These bacterial colonies are powdery in consistency and adhere tightly to the agar surface, producing hyphae and conidia / sporangium-like fungi in culture medium as well as various secondary metabolites with high pharmacological and commercial interest.
Types of ActinobacteriaWith the discovery of actinomycin, a number of antibiotics from actinobacteria, particularly the genus, have been discovered. They are widely found in soils with high acid sensitivity and low pH. Cellulose, polysaccharides, protein oils, organic acids, etc. It has a number of important functions, including breaking down and decomposing all kinds of organic matter. They are also responsible for the later decomposition of humus in the soil and the soil odor of freshly plowed soils. However, they produce a number of antibiotics such as streptomycin, terramycin, aureomycin.

Types of Actinobacteria

Actinobacteria are divided into 6 different species. As a result of the researches and examinations, many types of these six different species have been found. Species determined in line with the researches are as follows:
Thermophilic actinobacteria
Researchers have done many studies to confirm the presence of extremophilic and hypertolerant soil actinobacteria. It has been found that mesophilic actinobacteria can grow at an optimal temperature from 20 ° C to 42 ° C, among which are heat-resistant strains that can survive at 50 ° C. Moderately thermophilic actinobacteria have an optimum growth at 45 ° – 55 ° C, while solid thermophilic ones grow at an optimum temperature of 37 ° – 65 ° C and 55 ° – 60 ° C. Incubation temperatures of 28 °, 37 ° and 45 ° C are considered optimal for the isolation of soil mesophilic, heat-resistant and moderately thermophilic actinobacteria. Excluded from the class Actinomycetales, thermoactinomyces are defined as thermophilic forms depending on their phenotypic and molecular genetic characteristics, as well as among some species.
Acidophilic actinobacteria
Acidophilic actinobacteria, common in terrestrial habitats such as acidic forest and mine drainage soil, grow in the pH range of about 3.5 to 6.5 with optimum rates between 4.5 and 5.5. Acidophilic ones have been shown to consistently form two distinct clustered taxa, namely, neutrolerant acidophilic and strictly acidophilic cluster groups, based on numerical phenetic data. In addition, members of the two groups share common morphological and chemotaxonomic characteristics. Certainly, however, some members of the acidophilic group form a different taxon like genus. Streptacidiphilus is Kitasatospora and Streptomyces, assigned to the revised family Streptomycetaceae with the genera.
Halophilic actinobacteria
Halophilic actinobacteria are divided into different types according to their growth in environments containing different salt concentrations. Extreme halophiles grow best in environments containing 2.5-5.2 M salt, while borderline excess halophiles grow best in environments containing 1.5-4.0 M salt. Middle halophiles grow best in environments containing 0.5-2.5 M salt and finally in halotolerants that do not show an absolute value. Salt requirement for growth, but they usually grow well to very high salt concentrations and tolerate at least 100 g / l salt (equivalent to 1.7 M NaCl). For isolating halophilic actinobacteria, seawater, saline soils, salt lakes, saltwater and alkaline salt habitats are considered the best habitat locations. Generally, most are isolated from saline soils, some of which are as follows:
• Micromonospores,
• Rhodococcus,
• Streptomyces,
• Diet,
• Salinispora,
• Marinophilus,
• Solwaraspora,
• Salinibacterium,
• Aeromicrobium,
• Gordonia,
• Microbacterium,
• Mycobacterium,
• Nocardiopsis,
• Pseudonocardia,
• Actinomadura,
• Saccharopolyspora,
• Streptosporangium,
• Nonomuraea,
• Williamsia,
• Verrucosispora,
Endophytic actinobacteria
Types of ActinobacteriaEndophytic Actinobacteria are defined as those living in the interior of plants and apparently do not cause any visible changes in their hosts. They play specific roles, such as protecting host plants from insects and diseases. In addition, they make up a large part of the rhizosphere and are found in plants of the intensely studied species. Frankia, nitrogen-binding bacteria of non-legume plants and a few species of this genus Streptomyces these are phytopathogens. Generally, the endophytic Actinobacteria are as follows:
• Streptomyces,
• Streptoverticillium,
• Nocardia,
• Micromonospores,
• Kitasatospora,
• Pseudonocardia,
• Microbispora,
• Kibdelosporangium,
• Actinopolyspora,
• Nocardioides,
• Brevibacterium,
• Actinomadura,
• Glycomyces Plantactinospora,
• Polymorphospora,
• Promicromonospora,
Streptosporangium (also found in plants),
• Palicourea longifolia,
• Calycophyllum acreanum,
• Monstera spruceana,
• Croton lechleri,
• Cantua buxifolia,
• Siparuna crassifolia,
• Eucharis cyaneosperma,
Symbiotic actinobacteria
About 15% of the world’s nitrogen is naturally fixed by symbiotic relationships between various species. Frankia belongs to the family of actinobacteria and plants that form symbiotic relationships are called Frankia actinorhizal plants. Researchers have found more than 160 plants, including alder, Russian olive, bay fruit, sweet fern, bitter bush, and cliff rose, which are home to actinobacteria. They are capable of meeting most or all of the nitrogen needs of the Frankia host plant. Numerous Frankia species, including Casuarina isolates, form nitrogen-depleting (NIR) vesicles in vitro and planta. These nitrogen-fixing bacteria and their host plants are often pioneer species in young nitrogen-deficient and degraded soils such as moraines, volcanic currents and dunes.
Endosymbiotic actinobacteria
Endosymbiotic is any organism that lives in the body or in the cells of another organism. The endosymbiosis process is sometimes necessary, meaning that they cannot survive without endosymbionts or hosts. Phylum actinobacteria members have been identified as abundant members of sponge-associated microbial communities. It has been found to inhabit marine sponges as endosymbionts along with mycobacteria and they are as follows:
• Micrococcus,
• Micromonospora,
• Microbacterium,
• Brevibacterium,
• Kocuria,
• Corynebacterium,
• Rhodococcus,
• Brachybacterium,
• Rubrobacter,
• Streptomyces,
• Diet,
• Salinispora,
• Actinokineospora,
• Gordonia,
• Arthrobacter,
• Nocardiopsis,
• Rothia,
• Callyspongia aff,
• tangle
• Aplysina aerophoba,
• Spheciospongia vagabunda,
• Hemimycale culumella,
• Hyrtios erecta,
• Dysidea tupha,
• Callyspongia sp,
• Disidea avara,
• Amphimedon sp,
• Negombata magnifica,
However, actinobacterial endosymbionts have also been reported from different animal species and they are as follows:
• Hylobates hoolock,
• Rhinopithecus roxellanae,
• Rhinopithecus bieti,
• Panthera tigris altaica,
• Panthera tigris tigris,
• Panthera tigris amoyensis,
• Ailurus fulgens,
• Cavnlvara zlrsidae,
• Ursus thibetanus,
• Cervus elaphus,
• Elaphurus davidianus,
• Vicugna pacos,
Well actinobacterialTypes of Actinobacteria
Although actinobacteria are found in a variety of different habitats, some are also known to form close relationships with invertebrates and vertebrates. Symbiotic interactions are essentially essential for survival and reproduction because they play a crucial role in nutrition, detoxification of certain compounds, growth performance, and protection against pathogenic bacteria. Many studies have shown that some symbiotic actinobacterial species, namely probiotics, control bacterial diseases in livestock, poultry and aquaculture. They also positively affect host health by converting feed ingredients into microbial biomass and fermentation end products that can be used by the animal host.
Tan et al. Isolated streptomyces, nocardiopsis, and oerskovia from healthy goat droppings. Latha and Dhanasekaran similarly collected goat and chicken droppings from different parts of the Pudukkottai and Tiruchirappalli areas in Tamil Nadu. They isolated 87 actinobacterial cultures from goat and chicken droppings they collected. In addition, among them, 45 isolates were allocated to screen antibacterial activity and extracellular digestive enzyme production. As a result, the proion’s ability JD9 from streptomyces sp broiler intestines has all the properties required to satisfy the native actinobacterial probion for improved broiler production.

References:
mmbr.asm.org/content/80/1/1
sciencedirect.com/topics/medicine-and-dentistry/actinobacteria
researchgate.net/publication/294705164_An_Introduction_to_Actinobacteria
courses.lumenlearning.com/boundless-microbiology/chapter/gram-positive-bacteria-and-actinobacteria/

Writer: Ozlem Guvenc Agaoglu


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