Salinispora

Salinispora members are gram-positive, filamentous bacteria which form extensively branched hyphae with smooth surfaced spores that can occur in clusters or singles. with a much larger abundance and distribution of spores relative to growing individuals. They have been shown in culture to preferentially grow at the upper sediment layers where blooms at the sediment-seawater interface have been observed. Species and strains within Salinispora produce a wide variety of secondary metabolites. It is likely that the biosynthetic gene clusters producing these secondary metabolites were initially acquired via horizontal gene transfer, potentially explaining the high sequence similarity among species and strains. The wide array of different biosynthetic gene products may have also contributed to niche differentiation. The large production of species/strains' particular secondary metabolite lends evidence to the importance of them in bacterial survival, and can potentially be used to identify specific species and strains within the genus Salinispora. == Distribution ==

Salinispora are commonly found in tropical and subtropical near-shore marine sediments of the Atlantic, Pacific, and Indian oceans. They have been detected at depths up to 5699 m (undetermined whether actively growing or spores) and confirmed to be growing at depths up to 1100 m. == Pharmaceutical significance ==

Salinispora has been used as a model for analyzing genome sequence data in order to further uncover biosynthetic pathways among bacteria. This has been an integral part of research into using microbial natural products as leads for the discovery of traditional natural products and potential new drugs. Salinispora arenicola secondary metabolites Salinispora arenicola secondary metabolites have a broad range of pharmaceutical applications. There are over 20 natural compounds that can be isolated from Salinispora arenicola (e.g., arenamides, arenicolides, arenimycins or salinisporamycin). The potential applications for these compounds are extensive. Over nine compounds are related to cancer cells or cancer precursor inhibition; other compounds have shown antibiotic abilities for resistant bacteria, yeast and fungi. Cycloaspeptides could be a potential treatment for asthma, as it is slightly toxic to lung fibroblasts, the human lung cells responsible for inflammation. Other compounds could be used in treatments for heavy metal poisoning or cholesterol-lowering. for example, were found to be a potential inhibitor of human colon carcinoma. Other metabolites can be used as antioxidants or antibiotics. Pacificanones A and B are other metabolites with immunosuppressant capacities and possible applications in the treatment of allergies. Lomaiviticins A and B Salinispora pacifica produces a cytotoxic family of secondary metabolites called lomaiviticins. They were the first compounds isolated from the genus Salinispora, with the structures being published in 2001. It was initially reported that the producing bacterial strain was a new Micromonospora species with "Micromonospora lomaivitiensis" as the proposed name. Further gene sequence analysis revealed that the strain was in fact S. pacifica. There are two classes of this natural product: lomaiviticin A and lomaiviticin B. Both classes demonstrate potent activity that is damaging to DNA, and is observed to be highly cytotoxic against human cancer cells. Lomaiviticin A in particular generates the greatest activity and is the most abundant of the two. Due to their unique molecular architecture and biological activities, lomaiviticins are an ideal natural product for chemical synthesis. However, notwithstanding the interest shown by the synthetic chemistry community, total synthesis of lomaiviticins has not yet been achieved and the enzymatic chemistry associated with lomaiviticin assembly has not yet been extensively researched. From studying their distinctive structure, it is theorized that the synthesis of this product will lead to many novel enzymatic transformations. In addition to driving the discovery of new analogs through metabolic engineering or chemoenzymatic synthesis, further research could uncover applicable tools for biocatalysis and metabolic engineering. Salinispora tropica also produces antiprotealide, another anti-cancer agent which is potentially the strongest cancer inhibitor within the Salinospora secondary metabolite lists. This natural compound is a very potent cytotoxin for myeloma cells. == References ==