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The Actinomycetota are a phylum of mostly 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 soil systems. In soil they help to decompose the organic matter of dead organisms so the molecules can be taken up anew by plants. While this role is also played by fungi, Actinomycetota are much smaller and likely do not occupy the same ecological niche. In this role the colonies often grow extensive mycelia, like a fungus would, and the name of an important order of the phylum, Actinomycetales, reflects that they were long believed to be fungi. Some soil actinomycetota live symbiotically with the plants whose roots pervade the soil, fixing nitrogen for the plants in exchange for access to some of the plant's saccharides. Other species, such as many members of the genus Mycobacterium, are important pathogens.
Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynthesis, and application of polyketides has evolved. It is a large and diverse group of secondary metabolites caused by its complex biosynthesis which resembles that of fatty acid synthesis. Because of this diversity, polyketides can have various medicinal, agricultural, and industrial applications. Many polyketides are medicinal or exhibit acute toxicity. Biotechnology has enabled discovery of more naturally-occurring polyketides and evolution of new polyketides with novel or better bioactivity.
The avermectins are a series of drugs and pesticides used to treat parasitic worms and insect pests. They are a group of 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties. These naturally occurring compounds are generated as fermentation products by Streptomyces avermitilis, a soil actinomycete. Eight different avermectins were isolated in four pairs of homologue compounds, with a major (a-component) and minor (b-component) component usually in ratios of 80:20 to 90:10. Other anthelmintics derived from the avermectins include ivermectin, selamectin, doramectin, eprinomectin, and abamectin.
Dehalococcoides is a genus of bacteria within class Dehalococcoidia that obtain energy via the oxidation of hydrogen and subsequent reductive dehalogenation of halogenated organic compounds in a mode of anaerobic respiration called organohalide respiration. They are well known for their great potential to remediate halogenated ethenes and aromatics. They are the only bacteria known to transform highly chlorinated dioxins, PCBs. In addition, they are the only known bacteria to transform tetrachloroethene to ethene.
Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota. It contains about 250 genera, which makes it the most genera-rich taxon of the Prokaryotes. Several medically, ecologically, and scientifically important groups of bacteria belong to this class. It is composed by all Gram-negative microbes and is the most phylogenetically and physiologically diverse class of Proteobacteria.
Salinosporamide A (Marizomib) is a potent proteasome inhibitor being studied as a potential anticancer agent. It entered phase I human clinical trials for the treatment of multiple myeloma, only three years after its discovery in 2003. This marine natural product is produced by the obligate marine bacteria Salinispora tropica and Salinispora arenicola, which are found in ocean sediment. Salinosporamide A belongs to a family of compounds, known collectively as salinosporamides, which possess a densely functionalized γ-lactam-β-lactone bicyclic core.
Desosamine is a 3-(dimethylamino)-3,4,6-trideoxyhexose found in certain macrolide antibiotics such as the commonly prescribed erythromycin, azithromycin, clarithroymcin, methymycin, narbomycin, oleandomycin, picromycin and roxithromycin. As the name suggests, these macrolide antibiotics contain a macrolide or lactone ring and they are attached to the ring Desosamine which is crucial for bactericidal activity. The biological action of the desosamine-based macrolide antibiotics is to inhibit the bacterial ribosomal protein synthesis. These antibiotics which contain Desosamine are widely used to cure bacterial-causing infections in human respiratory system, skin, muscle tissues, and urethra.
Nereus Pharmaceuticals was a pharmaceutical company focused on the development of natural products from marine microbial and other natural sources into small molecule human therapeutics. The major disease area addressed by Nereus is cancer. Nereus was purchased by Triphase Research and Development in 2012.
The Nitrososphaerota are a phylum of the Archaea proposed in 2008 after the genome of Cenarchaeum symbiosum was sequenced and found to differ significantly from other members of the hyperthermophilic phylum Crenarchaeota. Three described species in addition to C. symbiosum are Nitrosopumilus maritimus, Nitrososphaera viennensis, and Nitrososphaera gargensis. The phylum was proposed in 2008 based on phylogenetic data, such as the sequences of these organisms' ribosomal RNA genes, and the presence of a form of type I topoisomerase that was previously thought to be unique to the eukaryotes. This assignment was confirmed by further analysis published in 2010 that examined the genomes of the ammonia-oxidizing archaea Nitrosopumilus maritimus and Nitrososphaera gargensis, concluding that these species form a distinct lineage that includes Cenarchaeum symbiosum. The lipid crenarchaeol has been found only in Nitrososphaerota, making it a potential biomarker for the phylum. Most organisms of this lineage thus far identified are chemolithoautotrophic ammonia-oxidizers and may play important roles in biogeochemical cycles, such as the nitrogen cycle and the carbon cycle. Metagenomic sequencing indicates that they constitute ~1% of the sea surface metagenome across many sites.
Sporolides A and B are polycyclic macrolides extracted from the obligate marine bacterium Salinispora tropica, which is found in ocean sediment. They are composed of a chlorinated cyclopenta[a]indene ring and a cyclohexenone moiety. They were the second group of compounds isolated from Salinispora, and were said to indicate the potential of marine actinomycetes as a source of novel secondary metabolites. The structures and absolute stereochemistries of both metabolites were elucidated using a combination of NMR spectroscopy and X-ray crystallography.
The salinosporamides are a group of closely related chemical compounds isolated from marine bacteria in the genus Salinispora. They possess a densely functionalized γ-lactam-β-lactone bicyclic core.
Anthracimycin is a polyketide antibiotic discovered in 2013. Anthracimycin is derived from marine actinobacteria. In preliminary laboratory research, it has shown activity against Bacillus anthracis, the bacteria that causes anthrax, and against methicillin-resistant Staphylococcus aureus (MRSA).
Salinispora arenicola is an obligate marine actinomycetes bacterium species. It produces salinosporamide, a potential anti-cancer agent. The type strain is CNH-643T.
Salinispora is a genus of obligately aerobic, gram-positive, non-acid-fast bacteria belonging to the family of Micromonosporaceae. They are heterotrophic, non-motile, and obligately grow under high osmotic/ionic-strength conditions. They are the first identified genus of gram-positive bacteria which has a high osmotic/ionic-strength requirement for survival. They are widely abundant in tropical marine sediments and were first identified in 2002. This genus of bacteria has potential biotechnological significance due to their production of novel secondary metabolites which can be used pharmaceutically.
Opitutus terrae is an obligately anaerobic bacterium first isolated from rice paddy soil, hence its epithet. It is coccus-shaped and is motile by means of a flagellum. Its type strain is PB90-1T. Its genome has been sequenced.
Salinispora pacifica is an obligate marine actinomycetes bacterium species in the genus Salinispora.
Microbial oxidation of sulfur is the oxidation of sulfur by microorganisms to build their structural components. The oxidation of inorganic compounds is the strategy primarily used by chemolithotrophic microorganisms to obtain energy to survive, grow and reproduce. Some inorganic forms of reduced sulfur, mainly sulfide (H2S/HS−) and elemental sulfur (S0), can be oxidized by chemolithotrophic sulfur-oxidizing prokaryotes, usually coupled to the reduction of energy-rich oxygen (O2) or nitrate (NO3−). Anaerobic sulfur oxidizers include photolithoautotrophs that obtain their energy from sunlight, hydrogen from sulfide, and carbon from carbon dioxide (CO2).
Cytophagales is an order of non-spore forming, rod-shaped, Gram-negative bacteria that move through a gliding or flexing motion. These chemoorganotrophs are important remineralizers of organic materials into micronutrients. They are widely dispersed in the environment, found in ecosystems including soil, freshwater, seawater and sea ice. Cytophagales is included in the Bacteroidota phylum.
Enterocin and its derivatives are bacteriocins synthesized by the lactic acid bacteria, Enterococcus. This class of polyketide antibiotics are effective against foodborne pathogens including L. monocytogenes, Listeria, and Bacillus. Due to its proteolytic degradability in the gastrointestinal tract, enterocin is used for controlling foodborne pathogens via human consumption.
Plastic degradation in marine bacteria describes when certain pelagic bacteria break down polymers and use them as a primary source of carbon for energy. Polymers such as polyethylene(PE), polypropylene (PP), and polyethylene terephthalate (PET) are incredibly useful for their durability and relatively low cost of production, however it is their persistence and difficulty to be properly disposed of that is leading to pollution of the environment and disruption of natural processes. It is estimated that each year there are 9-14 million metric tons of plastic that are entering the ocean due to inefficient solutions for their disposal. The biochemical pathways that allow for certain microbes to break down these polymers into less harmful byproducts has been a topic of study to develop a suitable anti-pollutant.
References
- ↑ Fenical, W.; Jensen, P.R.; Palladino, M.A.; Lam, K.S.; Lloyd, G.K.; Potts, B.C. (2009). "Discovery and development of the anticancer agent salinosporamide A (NPI-0052)". Bioorganic & Medicinal Chemistry. 17 (6): 2175–2180. doi:10.1016/j.bmc.2008.10.075. PMC 2814440 . PMID 19022674.
- ↑ Maldonado, L. A. (2005). "Salinispora arenicola gen. nov., sp. nov. and Salinispora tropica sp. nov., obligate marine actinomycetes belonging to the family Micromonosporaceae". International Journal of Systematic and Evolutionary Microbiology. 55 (5): 1759–1766. doi: 10.1099/ijs.0.63625-0 . ISSN 1466-5026. PMID 16166663.
- ↑ Williams PG; Buchanan GO; Feling RH; Kauffman CA; Jensen PR; Fenical W (August 2005). "New cytotoxic salinosporamides from the marine Actinomycete Salinispora tropica". The Journal of Organic Chemistry . 70 (16): 6196–203. doi:10.1021/jo050511+. PMID 16050677.
- ↑ Buchanan, Greg O.; Williams, Philip G.; Feling, Robert H.; Kauffman, Christopher A.; Jensen, Paul R.; Fenical, William (2005). "Sporolides a and b: Structurally Unprecedented Halogenated Macrolides from the Marine Actinomycete Salinispora tropica". Organic Letters. 7 (13): 2731–2734. doi:10.1021/ol050901i. PMID 15957933.
