Symplostatin 3 (1), a new analogue of dolastatin 10 (2), has been isolated from a tumor selective extract of a Hawaiian variety of the marine cyanobacterium Symploca sp. VP452. Compound 1 differs from 2 only in the C-terminal unit; the dolaphenine unit is substituted by a 3-phenyllactic acid residue. Symplostatin 3 (1) possesses IC(50) values for in vitro cytotoxicity toward human tumor cell lines ranging from 3.9 to 10.3 nM. It disrupts microtubules, but at a higher concentration than 2, correlating with the weaker in vitro cytotoxicity.
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http://dx.doi.org/10.1021/np010317s | DOI Listing |
Nat Microbiol
January 2025
Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.
Synechococcus is a significant primary producer in the oceans, coexisting with cyanophages, which are important agents of mortality. Bacterial resistance against phage infection is a topic of significant interest, yet little is known for ecologically relevant systems. Here we use exogenous gene expression and gene disruption to investigate mechanisms underlying intracellular resistance of marine Synechococcus WH5701 to the Syn9 cyanophage.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Cross-feeding involves microbes consuming exudates of other surrounding microbes, mediating elemental cycling. Characterizing the diversity of cross-feeding pathways in ocean microbes illuminates evolutionary forces driving self-organization of ocean ecosystems. Here, we uncover a purine and pyrimidine cross-feeding network in globally abundant groups.
View Article and Find Full Text PDFToxins (Basel)
December 2024
Cawthron Institute, Molecular Algal Ecology, Nelson 7010, New Zealand.
This study reports the first documented accumulation of lyngbyatoxin-a (LTA), a cyanotoxin produced by marine benthic cyanobacteria, in edible shellfish in Aotearoa New Zealand. The study investigates two bloom events in 2022 and 2023 on Waiheke Island, where hundreds of tonnes of marine benthic cyanobacterial mats (mBCMs) washed ashore each summer. Genetic analysis identified the cyanobacterium responsible for the blooms as sp.
View Article and Find Full Text PDFMar Drugs
November 2024
College of Chemistry, Nankai University, Tianjin 300071, China.
Majusculamide D, isolated from the marine cyanobacterium , is an anticancer lipopentapeptide consisting of fatty acid, tripeptide, and pyrrolyl proline moieties. In this work, by utilizing a convergent synthetic approach, late-stage modification, and bioisostere strategy, 26 majusculamide D analogues were synthesized, and two ( and ) demonstrated IC values < 1 nM against PANC-1 cancer cells. The results summarized a preliminary structure-activity relationship mainly at the C23, C4, C34, and C10 sites.
View Article and Find Full Text PDFJ Nat Prod
December 2024
Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Avenida General Norton de Matos, s/n4450-208Matosinhos, Portugal.
Genome mining has emerged as an important tool for the discovery of natural products and is particularly effective for the swift identification of ribosomally synthesized and post-translationally modified peptides (RiPPs). Among RiPPs, cyanobactins have gained attention due to their diverse structures and bioactive properties. Here, we explored the Microcoleaceae cyanobacterium LEGE 16532 strain and identified the biosynthetic gene cluster (BGC), which was predicted to encode cyanobactin-like molecules.
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