Actinomycetes Krasil'nikov The Actinobacteria are a phylum of Gram-positive bacteria.
This article has been cited by other articles in PMC. Abstract The marine environment represents a largely untapped source for isolation of new microorganisms with potential to produce biologically active secondary metabolites.
Among such microorganisms, Gram-positive actinomycete bacteria are of special interest, since they are known to produce chemically diverse compounds with a wide range of biological activities. We have set out to isolate and characterize actinomycete bacteria from the sediments in one of the largest Norwegian fjords, the Trondheim fjord, with respect to diversity and antibiotic-producing potential.
Approximately 3, actinomycete bacteria were isolated using four different agar media from the sediment samples collected at different locations and depths 4.
Grouping of the isolates first according to the morphology followed by characterization of isolates chosen as group representatives by molecular taxonomy revealed that Micromonospora was the dominating actinomycete genus isolated from the sediments.
The deep water sediments contained a higher relative amount of Micromonospora compared to the shallow water samples. Nine percent of the isolates clearly required sea water for normal growth, suggesting that these strains represent obligate marine organisms.
Extensive screening of the extracts from all collected isolates for antibacterial and antifungal activities revealed strong antibiotic-producing potential among them.
The latter implies that actinomycetes from marine sediments in Norwegian fjords can be potential sources for the discovery of novel anti-infective agents.
Actinomycete bacteria, fjord sediments, molecular taxonomy, antimicrobial activities Introduction The demand for new antibiotics continues to grow due to the rapid spread of antibiotic-resistant pathogens causing life-threatening infections.
Although considerable progress is being made within the fields of chemical synthesis and engineered biosynthesis of antimicrobial compounds, nature still remains the richest and the most versatile source for new antibiotics [ 123 ]. Bacteria belonging to the family Actinomycetaceae are well known for their ability to produce secondary metabolites, many of which are active against pathogenic microorganisms.
Traditionally, these bacteria have been isolated from terrestrial sources although the first report of mycelium-forming actinomycetes being recovered from marine sediments appeared several decades ago [ 4 ].
It is only more recently that marine-derived actinomycetes have become recognized as a source of novel antibiotics and anti-cancer agents with unusual structures and properties [ 5 ]. Many microbiologists believe that free-living bacteria are cosmopolitan due to their easy dispersal [ 6 ].
However, chemical and physical factors contribute to selection of species and strains that are best adapted to that particular environment. Due to the broad bacterial species definition one may find members of one species in two very different environments [ 78 ]. However, comprehensive analysis of the recent studies strongly suggests that free-living microbial taxa exhibit biogeographic patterns [ 79 ].
Fjords are narrow inlets of the sea, which have been formed as a result of marine inundation of glaciated valleys. Typical characteristics of a fjord include a relatively narrow inlet, significantly eroded bottom and communication with the open sea.
The ecology of the microorganisms, especially bacteria, inhabiting the fjords is poorly studied. The Trondheim fjord km long differs from many other fjords by a large fresh water supplement from six major river systems. In one year these rivers bring fresh water to the fjord corresponding to 6.
From May until September the fjord contains a m thick layer of brackish surface water, depending on time, weather and location. In the brackish water layer the salt content varies from approximately 18 to 32 practical salinity units PSU.
The dissolved and particulate organic matter in the sediments from the fjord has both marine origin from phytoplankton and macroalgae as well as terrestrial from soil due to fresh water run-off, highly influenced by snow melting in April-May.
The Norwegian marine environments are largely unexplored, and may provide a rich source of the microorganisms producing novel and efficient anti-infective compounds. The purpose of this study was to investigate if fjord sediments from temperate areas could be suitable sources for isolation of mycelium-forming actinomycetes producing antimicrobial compounds.
Results Collection and analysis of the sediment samples Sediment samples from two different locations and five depths were collected and processed see Table 1 for description and ID.
The first site B-site was close to the shore and here samples were collected at depths of 4. The second site T-site was located in the middle of the fjord and here samples were taken at m depth, where the sediment was dominated by clay particles.
Visual inspection indicated a higher content of fine organic matter than in the other sediments. Similar to the B2 sample the sediments from this location also had a layer of dead micro algae on the surface. Table 1 Description of sediments and sampling sites.CHAPTER Nitrogen fixation and nitrogen metabolism.
Introduction Living organisms need nitrogen because it is a part of the amino acids that make up proteins, and the nucleic acids that make up DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).Nitrogen(dinitrogen, N2) is highly inter gas.
Distribution and Deposit of Biological Resources Microbial resources such as bacteria including actinomycetes and archaea, yeasts, fungi, algae, bacteriophages and DNA resources for academic research and industrial applications.
The Epidemiology Of Tuberculosis (Tb) - In extreme cases, TB can affect the brain’s membrane and the tissues surrounding the heart, risking fatality (Mayo Clinic, ).
Boron is an essential element for plants and probably essential for human and animal health. Boron has a broad range of physiological effects on biological systems at low concentrations, whereas it is toxic to at high concentrations.
Actinomycetes are a broad group of bacteria that form thread-like filaments in the soil. The distinctive scent of freshly exposed, moist soil is attributed to these organisms, especially to the nutrients they release as a result of their metabolic processes. Gold nanoparticles have been also used for tumor detection, angiogenesis, genetic disease and genetic disorder diagnosis, photoimaging, and photothermal therapy.
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