Six novel species of the obligate marine actinobacterium , sp. nov., sp. nov., sp. nov., sp. nov., sp. nov. and sp. nov., and emended description of the genus .

Ten representative actinobacterial strains isolated from marine sediments collected worldwide were studied to determine their taxonomic status. The strains were previously identified as members of the genus and shared >99 % 16S rRNA gene sequence similarity to the three currently recognized species. Comparative genomic analyses resulted in the delineation of six new species based on average nucleotide identity and digital DNA-DNA hybridization values below 95 and 70 %, respectively.

Marinocyanins, cytotoxic bromo-phenazinone meroterpenoids from a marine bacterium from the streptomycete clade MAR4.

Six cytotoxic and antimicrobial metabolites of a new bromo-phenazinone class, the marinocyanins A-F (-), were isolated together with the known bacterial metabolites 2-bromo-1-hydroxyphenazine (), lavanducyanin ( WS-9659A) and its chlorinated analog WS-9659B (). These metabolites were purified by bioassay-guided fractionation of the extracts of our MAR4 marine actinomycete strains CNS-284 and CNY-960. The structures of the new compounds were determined by detailed spectroscopic methods and marinocyanin A () was confirmed by crystallographic methods.

Plant-derived antimicrobials to fight against multi-drug-resistant human pathogens.

Antibiotic resistance is becoming a pivotal concern for public health that has accelerated the search for new antimicrobial molecules from nature. Numbers of human pathogens have inevitably evolved to become resistant to various currently available drugs causing considerable mortality and morbidity worldwide. It is apparent that novel antibiotics are urgently warranted to combat these life-threatening pathogens.

Aurantoside K, a new antifungal tetramic acid glycoside from a Fijian marine sponge of the genus Melophlus.

A new tetramic acid glycoside, aurantoside K, was isolated from a marine sponge belonging to the genus Melophlus. The structure of the compound was elucidated on the basis of spectroscopic analysis (¹H NMR, ¹H-¹H COSY, HSQC, and HMBC, as well as high-resolution ESILCMS). Aurantoside K did not show any significant activity in antimalarial, antibacterial, or HCT-116 cytotoxicity assays, but exhibited a wide spectrum of antifungal activity against wild type Candida albicans, amphotericin-resistant C.

Papuamides E and F, Cytotoxic Depsipeptides from the Marine Sponge Melophlus sp.

Two known papuamides C (1) and D (2) together with two new depsipeptides, papuamides E (3) and F (4), were isolated from an undescribed sponge of the genus Melophlus collected in the Solomon Islands. The planar structures of the compounds were elucidated on the basis of spectroscopic studies. Papuamides C-F (1-4) showed cytotoxicity against brine shrimp with LD(50) values between 92 and 106 μg/mL.