Identifying the core microbiome of the sea star Pisaster ochraceus in the context of sea star wasting disease.

Sea stars are keystone species and their mass die-offs due to sea star wasting disease (SSWD) impact marine communities and have fueled recent interest in the microbiome of sea stars. We assessed the host specificity of the microbiome associated with three body regions of the sea star Pisaster ochraceus using 16S rRNA gene amplicon surveys of the bacterial communities living on and in Pisaster, their environment, and sympatric marine hosts across three populations in British Columbia, Canada. Overall, the bacterial communities on Pisaster are distinct from their environment and differ by both body region and geography. We identified core bacteria specifically associated with Pisaster across populations and nearly absent in other hosts and the environment. We then investigated the distribution of these core bacteria on SSWD-affected Pisaster from one BC site and by reanalyzing a study of SSWD on Pisaster from California. We find no differences in the distribution of core bacteria in early disease at either site and two core taxa differ in relative abundance in advanced disease in California. Using phylogenetic analyses, we find that most core bacteria have close relatives on other sea stars and marine animals, suggesting these clades have evolutionary adaptions to an animal-associated lifestyle.

A ubiquitous subcuticular bacterial symbiont of a coral predator, the crown-of-thorns starfish, in the Indo-Pacific.

BACKGROUND: Population outbreaks of the crown-of-thorns starfish (Acanthaster planci sensu lato; COTS), a primary predator of reef-building corals in the Indo-Pacific Ocean, are a major threat to coral reefs. While biological and ecological knowledge of COTS has been accumulating since the 1960s, little is known about its associated bacteria. The aim of this study was to provide fundamental information on the dominant COTS-associated bacteria through a multifaceted molecular approach. METHODS: A total of 205 COTS individuals from 17 locations throughout the Indo-Pacific Ocean were examined for the presence of COTS-associated bacteria. We conducted 16S rRNA metabarcoding of COTS to determine the bacterial profiles of different parts of the body and generated a full-length 16S rRNA gene sequence from a single dominant bacterium, which we designated COTS27. We performed phylogenetic analysis to determine the taxonomy, screening of COTS27 across the Indo-Pacific, FISH to visualize it within the COTS tissues, and reconstruction of the bacterial genome from the hologenome sequence data. RESULTS: We discovered that a single bacterium exists at high densities in the subcuticular space in COTS forming a biofilm-like structure between the cuticle and the epidermis. COTS27 belongs to a clade that presumably represents a distinct order (so-called marine spirochetes) in the phylum Spirochaetes and is universally present in COTS throughout the Indo-Pacific Ocean. The reconstructed genome of COTS27 includes some genetic traits that are probably linked to adaptation to marine environments and evolution as an extracellular endosymbiont in subcuticular spaces. CONCLUSIONS: COTS27 can be found in three allopatric COTS species, ranging from the northern Red Sea to the Pacific, implying that the symbiotic relationship arose before the speciation events (approximately 2 million years ago). The universal association of COTS27 with COTS and nearly mono-specific association at least with the Indo-Pacific COTS provides a useful model system for studying symbiont-host interactions in marine invertebrates and may have applications for coral reef conservation. Video Abstract.

Patiriisocius marinistellae gen. nov., sp. nov., isolated from the starfish Patiria pectinifera, and reclassification of Ulvibacter marinus as a member of the genus Patiriisocius comb. nov.

A marine strain, designated KK4T, was isolated from the surface of a starfish, Patiria pectinifera, which was collected from seawater off the coast of Hokkaido, Japan. Strain KK4T is a Gram-stain-negative, non-spore-forming, rod-shaped, aerobic bacterium that forms yellow-pigmented colonies. A phylogenetic relationship analysis, based on 16S rRNA gene sequences, revealed that strain KK4T was closely related to Ulvibacter marinus IMCC12008T, Ulvibacter antarcticus IMCC3101T and Ulvibacter litoralis KMM 3912T, with similarities of 96.9, 95.8 and 95.6 %, respectively, but low sequence similarities (<94 %) among other genera in the family Flavobacteriaceae. Genomic similarities between strain KK4T and the three Ulvibacter type strains based on average nucleotide identity and digital DNA-DNA hybridization values were lower than the species delineation thresholds. Moreover, phylogenetic tree based on genome sequences showed that strain KK4T was clustered with U. marinus IMCC12008T and formed a branch independent from the cluster including type species of the genera Ulvibacter, Marixanthomonas, Marinirhabdus, Aureitalea and Aequorivita. Amino acid identity values between strain KK4T/U. marinus IMCC12008T and the neighbour type species/strains were 61.9-68.2% and 61.5-67.4 %, which were lower than the genus delineation threshold, implying the novel genus status of strain KK4T. Strain KK4T growth occurred at pH 6.0-9.0, 4-30 °C and in NaCl concentrations of 0.5-5.0 %, and optimally at pH 7.0, 25 °C and 3.0 %, respectively. Unlike Ulvibacter strains, strain KK4T could assimilate glucose, mannose, galactose and acetate. The major quinone and fatty acids were menaquinone-6 and iso-C15 : 0 (27.5 %), iso-C15 : 1 G (22.5 %) and iso-C17 : 0 3-OH (12.8 %), respectively. Based on genetic, phylogenetic and phenotypic properties, strain KK4T represents a novel species of the genus Patiriisocius, for which the name Patiriisocius marinistellae gen. nov., sp. nov. is proposed. The type strain is KK4T (=JCM 33344T=KCTC 72225T). In addition, based on the current data, Ulvibacter marinus should be reclassified as Patiriisocius marinus comb. nov.

Enhanced bioactivity of Zanthoxylum schinifolium fermented extract: Anti-inflammatory, anti-bacterial, and anti-melanogenic activity.

Fermented extracts have evolved to be a potential alternative to synthetic chemicals, owing to their anti-inflammatory and anti-bacterial properties. This study intends to assess the potential of fermented Zanthoxylum schinifolium extract for use in biomedical applications. Probiotic bacteria, Lactobacillus rhamnosus A6-5, were deployed as a seed culture for fermentation. The fermented extract showed greater tyrosinase inhibitory activity and reduced melanin production (58.3%) compared with the raw extract. Cytotoxicity assay inferred that 500 µg/mL is the ideal non-toxic concentration with maximum cell viability. In addition, DAPI staining did not show any damage to the chromatin structure of the cells. The anti-aging property of the fermented extract was confirmed by a decrease in IL-6 content. The fermented extract showed lower MIC (40 mg/mL) and MBC (60 mg/mL), indicating greater anti-bacterial activity than the raw extract. The results confirmed that the fermented Z. schinifolium extract has high biomedical properties compared with the raw extract and can be used as an ideal skin whitening agent.

Enantiomeric Polyketides from the Starfish-Derived Symbiotic Fungus Penicillium sp. GGF16-1-2.

One new racemic mixture, penicilliode A (1) and four pairs of enantiomeric polyketides, penicilliode B and C (2 and 3) and coniochaetone B and C (4 and 5), were obtained from the starfish-derived symbiotic fungus Penicillium sp. GGF16-1-2. Interestingly, the strain GGF16-1-2 can produce enantiomers. The absolute configuration of 1 was determined by X-ray diffraction (XRD) analysis, and the absolute configurations of 2-4 were determined by the optical rotation (OR) values and electronic circular dichroism (ECD) calculations. Compounds 1-5 were firstly isolated from the marine-derived fungus Penicillium as racemates, and 2-5 were separated by HPLC with a chiral stationary phase. All the compounds were evaluated for their antibacterial, cytotoxic and inhibitory activities against PDE4D2.

Reciprocal abundance shifts of the intertidal sea stars, Evasterias troschelii and Pisaster ochraceus, following sea star wasting disease.

Disease emergence occurs within the context of ecological communities, and disease driven declines in host populations can lead to complex direct and indirect ecological effects. Varying effects of a single disease among multiple susceptible hosts could benefit relatively resistant species. Beginning in 2013, an outbreak of sea star wasting disease (SSWD) led to population declines of many sea star species along the west coast of North America. Through field surveys and laboratory experiments, we investigated how and why the relative abundances of two co-occurring sea star species, Evasterias troschelii and Pisaster ochraceus, shifted during the ongoing wasting epidemic in Burrard Inlet, British Columbia, Canada. We hypothesized that Evasterias is competitively inferior to Pisaster but more resistant to SSWD. Thus, we predicted that SSWD-induced declines of Pisaster could mitigate the negative effects of SSWD on Evasterias, as the latter would experience competitive release. We document shifts in sea star abundance from 2008-2017: Pisaster abundance and mean size declined during the outbreak, while Evasterias abundance increased from relatively rare to numerically dominant within the intertidal. When exposed to symptomatic sea stars, Pisaster and Evasterias both showed signs of SSWD, but transmission and susceptibility was lower in Evasterias. Despite diet overlap documented in our field surveys, Evasterias was not outcompeted by Pisaster in laboratory trails conducted with the relatively small Pisaster available after the outbreak. Interference competition with larger Pisaster, or prey exploitation by Pisaster during the summer when Evasterias is primarily subtidal, may explain the rarity of Evasterias prior to Pisaster declines. Our results suggest that indirect effects mediated by competition can mask some of the direct effects of disease outbreaks, and the combination of direct and indirect effects will determine the restructuring of a community after disturbance.

Microbiome shifts with onset and progression of Sea Star Wasting Disease revealed through time course sampling.

The recent outbreak of Sea Star Wasting Disease (SSWD) is one of the largest marine epizootics in history, but the host-associated microbial community changes specific to disease progression have not been characterized. Here, we sampled the microbiomes of ochre sea stars, Pisaster ochraceus, through time as animals stayed healthy or became sick and died with SSWD. We found community-wide differences in the microbiomes of sick and healthy sea stars, changes in microbial community composition through disease progression, and a decrease in species richness of the microbiome in late stages of SSWD. Known beneficial taxa (Pseudoalteromonas spp.) decreased in abundance at symptom onset and through disease progression, while known pathogenic (Tenacibaculum spp.) and putatively opportunistic bacteria (Polaribacter spp. and Phaeobacter spp.) increased in abundance in early and late disease stages. Functional profiling revealed microbes more abundant in healthy animals performed functions that inhibit growth of other microbes, including pathogen detection, biosynthesis of secondary metabolites, and degradation of xenobiotics. Changes in microbial composition with disease onset and progression suggest that a microbial imbalance of the host could lead to SSWD or be a consequence of infection by another pathogen. This work highlights the importance of the microbiome in SSWD and also suggests that a healthy microbiome may help confer resistance to SSWD.

Crown-of-Thorns Sea Star Acanthaster cf. solaris Has Tissue-Characteristic Microbiomes with Potential Roles in Health and Reproduction.

Outbreaks of coral-eating crown-of-thorns sea stars (CoTS; Acanthaster species complex) cause substantial coral loss; hence, there is considerable interest in developing prevention and control strategies. We characterized the microbiome of captive CoTS and assessed whether dysbiosis was evident in sea stars during a disease event. Most tissue types had a distinct microbiome. The exception was female gonads, in which the microbiomes were highly variable among individuals. Male gonads were dominated (>97% of reads) by a single Mollicutes-related operational taxonomic unit (OTU). Detailed phylogenetic and microscopy analysis demonstrated the presence of a novel Spiroplasma-related bacterium in the spermatogenic layer. Body wall samples had high relative abundance (43 to 64% of reads) of spirochetes, likely corresponding to subcuticular symbionts reported from many echinoderms. Tube feet were characterized by Hyphomonadaceae (24 to 55% of reads). Pyloric cecal microbiomes had high alpha diversity, comprising many taxa commonly found in gastrointestinal systems. The order Oceanospirillales (genera Endozoicomonas and Kistimonas) was detected in all tissues. A microbiome shift occurred in diseased individuals although differences between tissue types were retained. The relative abundance of spirochetes was significantly reduced in diseased individuals. Kistimonas was present in all diseased individuals and significantly associated with diseased tube feet, but its role in disease causation is unknown. While Arcobacter was significantly associated with diseased tissues and Vibrionaceae increased in diversity, no single OTU was detected in all diseased individuals, suggesting opportunistic proliferation of these taxa in this case. This study shows that CoTS have tissue-characteristic bacterial communities and identifies taxa that could play a role in reproduction and host health.IMPORTANCE Coral-eating crown-of-thorns sea stars (CoTS; Acanthaster species complex) are native to the Indo-Pacific, but during periodic population outbreaks they can reach extreme densities (>1,000 starfish per hectare) and function as a pest species. On the Great Barrier Reef, Australia, CoTS have long been considered one of the major contributors to coral loss. There has been significant investment in a targeted control program using lethal injection, and there is interest in developing additional and complementary technologies that can increase culling efficiencies. The biology of CoTS has been studied extensively, but little is known about their associated microbiome. This cultivation-independent analysis of the CoTS microbiome provides a baseline for future analyses targeting the functional role of symbionts, the identification of pathogens, or the development of reproduction manipulators.

A member of the Roseobacter clade, Octadecabacter sp., is the dominant symbiont in the brittle star Amphipholis squamata.

Symbiotic associations with subcuticular bacteria (SCB) have been identified and studied in many echinoderms, including the SCB of the brooding brittle star, Amphipholis squamata. Previous studies on the SCB of A. squamata placed the isolated bacterium, designated as AS1, in the genus Vibrio (Gammaproteobacteria), but subsequent studies suggested that the SCB of echinoderms belong to the Alphaproteobacteria. This study examines the taxonomic composition of SCB associated with A. squamata from the Northwest Atlantic using the 16S rRNA gene and next generation sequencing. Results show the presence of a single dominant bacterial type, within the Roseobacter clade, family Rhodobacteraceae, which composes 70%-80% of the A. squamata microbiome. These Rhodobacteraceae sequences were identified as members of the genus Octadecabacter. Additionally, the original isolate, AS1, from the brittle star A. squamata also belongs in the genus Octadecabacter based on Sanger sequencing of cloned 16S rRNA gene sequences. By comparison, adjacent seawater and sediment porewater communities were significantly more diverse, hosting bacteria in the phyla Proteobacteria, Bacteroidetes, Cyanobacteria, Verrucomicrobia and Actinobacteria. Thus, a distinct SCB community is present in A. squamata that is dominated by a member of the genus Octadecabacter and is identical to the original isolate, AS1, from this brittle star.

Microbiota in the coelomic fluid of two common coastal starfish species and characterization of an abundant Helicobacter-related taxon.

Marine invertebrates associate with diverse microorganisms. Microorganisms even inhabit coelomic fluid (CF), namely, the fluid filling the main body cavity of echinoderms. The CF microbiota potentially impacts host health and disease. Here, we analysed the CF microbiota in two common coastal starfish species, Patiria pectinifera and Asterias amurensis. Although microbial community structures were highly variable among individual starfish, those of P. pectinifera were compositionally similar to those in the surrounding seawater. By contrast, many A. amurensis individuals harboured unique microbes in the CF, which was dominated by the unclassified Thiotrichales or previously unknown Helicobacter-related taxon. In some individuals, the Helicobacter-related taxon was the most abundant genus-level taxon, accounting for up to 97.3% of reads obtained from the CF microbial community. Fluorescence in situ hybridization using a Helicobacter-related-taxon-specific probe suggested that probe-reactive cells in A. amurensis were spiral-shaped, morphologically similar to known Helicobacter species. Electron microscopy revealed that the spiral cells had a prosthecate-like polar appendage that has never been reported in Helicobacter species. Although culture of Helicobacter-related taxon was unsuccessful, this is the first report of the dominance of a Helicobacter-related taxon in invertebrates and non-digestive organs, reshaping our knowledge of the phylogeography of Helicobacter-related taxa.

Probiotic-mediated blueberry (Vaccinium corymbosum L.) fruit fermentation to yield functionalized products for augmented antibacterial and antioxidant activity.

The aim of this study was to investigate the fermentation of blueberry fruit with selected probiotic bacteria (Bacillus amyloliquefaciens and Lactobacillus brevis) and yeast (Starmerella bombicola) isolated from fermented starfish for the extraction of functionalized products for biomedical applications. All probiotic-based fermented extracts showed augmented antibacterial and antioxidant activity compared to the control. Biochemical parameters of viable cell count, titratable acidity, total phenol, total anthocyanin, total flavonoids, total sugar, and reducing sugar were analyzed during a 0-96 h fermentation period. In addition, Fourier transform infrared (FTIR) spectroscopy was performed to determine the functional groups in the control and fermented extracts and it signifies the presence of alcohol groups, phenol groups, carboxylic acids, and aliphatic amines, respectively. The well diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays determined that the S. bombicola-mediated fermented extract has excellent activity, followed by B. amyloliquefaciens and L. brevis, at a high concentration of 1.0 g/mL fermented extract. The ABTS and DPPH showed significant scavenging activity with IC50 values of (30.52 ± 0.08)/(155.10 ± 0.06) µg/mL, (24.82 ± 0.16)/(74.21 ± 1.26) µg/mL, and (21.81 ± 0.08)/(125.11 ± 0.04) µg/mL for B. amyloliquefaciens, L. brevis, and S. bombicola, respectively. Developing a value-added fermented blueberry product will help circumvent losses because of the highly perishable nature of the fruit.

Pseudoruegeria marinistellae sp. nov., isolated from an unidentified starfish in Sanya, China.

A taxonomic study was carried out on a Gram-stain negative, rod-shaped, non-flagellated, and facultatively anaerobic bacterial strain designated as strain SF-16T, which was isolated from an unidentified starfish in Sanya, China. Strain SF-16T was found to be 5.0-7.0 µm long, and oxidase and catalase positive. Cell growth was observed at pH 6.0-8.5 (optimum, 7.0-8.0), temperatures of 10-41 °C (optimum, 25-30 °C), and salinities of 0-12 % (optimum, 3.0-6.0 %). The predominant fatty acids (>20 %) were found to be C18:1 ω7c and/or C18:1 ω6c (summed feature 8). Ubiquinone 10 was identified as the predominant quinone for strain SF-16T. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids, two unidentified lipids, and three unidentified phospholipids. The DNA G+C content of the genomic DNA of strain SF-16T was determined to be 63.0 mol%. Phylogenetic analysis based on the 16S rRNA gene showed that strain SF-16T belongs to the genus Pseudoruegeria and is closely related to Pseudoruegeria sabulilitoris GJMS-35T (98.42 % similarity). The ANI value between strain SF-16T and P. sabulilitoris GJMS-35T was found to be 74.98 %, and DNA-DNA hybridization value was 21.1 ± 2.3 % in silico and 57 % in vitro. Based on the low level of the genetic relatedness, phylogenetic and phenotypic data, a novel species Pseudoruegeria marinistellae sp. nov. is proposed. The type strain is SF-16T (=MCCC 1K01155T = KCTC 42910T).

Bioprospecting from cultivable bacterial communities of marine sediment and invertebrates from the underexplored Ubatuba region of Brazil.

Shrimp fisheries along the Brazilian coast have significant environmental impact due to high by-catch rates (21 kg per kilogram of shrimp). Typically discarded, by-catch contains many invertebrates that may host a great variety of bacterial genera, some of which may produce bioactive natural products with biotechnological applications. Therefore, to utilize by-catch that is usually discarded we explored the biotechnological potential of culturable bacteria of two abundant by-catch invertebrate species, the snail Olivancillaria urceus and the sea star Luidia senegalensis. Sediment from the collection area was also investigated. Utilizing multiple isolation approaches, 134 isolates were obtained from the invertebrates and sediment. Small-subunit rRNA (16S) gene sequencing revealed that the isolates belonged to Proteobacteria, Firmicutes and Actinobacteria phyla and were distributed among 28 genera. Several genera known for their capacity to produce bioactive natural products (Micromonospora, Streptomyces, Serinicoccus and Verrucosispora) were retrieved from the invertebrate samples. To query the bacterial isolates for their ability to produce bioactive metabolites, all strains were fermented and fermentation extracts profiled by UP LC-HRMS and tested for antimicrobial activity. Four strains exhibited antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus warneri.

Lutimaribacter marinistellae sp. nov., isolated from a starfish.

A taxonomic study was carried out on a Gram-staining-negative bacterium, strain SF-12T, isolated from an unidentified starfish living in Sanya, PR China. Cells of SF-12T were non-spore-forming rods, 0.5-0.8 µm wide, 2.2-2.5 µm long and motile by means of flagella. SF-12T was facultatively anaerobic, heterotrophic, oxidase- and catalase-positive. Growth of SF-12T occurred at 15-38 °C (optimum, 30 °C), at pH 6.5-8.5 (optimum, pH 7.0), and in the presence of 2.0-7.0 % (w/v) NaCl (optimum, 3.0-4.0 %). The predominant fatty acids of SF-12T were C18 : 1ω7c and/or C18 : 1ω6c. Ubiquinone 10 was the sole respiratory quinone of SF-12T. The major polar lipids of SF-12T were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, three unknown aminolipids, and seven unknown phospholipids. The DNA G+C content was 61 mol%. SF-12T showed the highest 16S rRNA gene sequence similarity to Lutimaribacter pacificus W11-2BT (96.06 %), followed by Cribrihabitans neustonicus CC-AMHB-3T (96.02 %), Lutimaribacter saemankumensis SMK-117T (96.0 %), Cribrihabitans marinus CZ-AM5T (95.92 %), Lutimaribacter litoralis KU5D5T (95.92 %) and other species of the family Rhodobacteraceae(<95.9 %). However, phylogenetic trees based on 16S rRNA gene sequences showed that SF-12T formed a lineage with members of the genus Lutimaribacter in the trees. On the basis of phenotypic, chemotaxonomic and phylogenetic analyses, SF-12T is considered to represent a novel species of the genus Lutimaribacter, for which the name Lutimaribacter marinistellae sp. nov. is proposed. The type strain is SF-12T (=MCCC 1K01154T=KCTC 42911T).

Two chlorinated benzofuran derivatives from the marine fungus Pseudallescheria boydii.

The marine fungus Pseudallescheria boydii was isolated from the inner tissue of the starfish Acanthaster planci. This fungus was cultured in a high salinity glucose-peptone-yeast extract (GPY) medium. Two new chlorinated benzofuran derivatives, 6-chloro-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5 hydroxybenzofuran (1) and 7-chloro-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-hydroxybenzofuran (2), were obtained from the extract of the culture broth. Their structures were determined by analysis of the NMR and MS data.

Exploring the chemodiversity and biological activities of the secondary metabolites from the marine fungus Neosartorya pseudofischeri.

The production of fungal metabolites can be remarkably influenced by various cultivation parameters. To explore the biosynthetic potentials of the marine fungus, Neosartorya pseudofischeri, which was isolated from the inner tissue of starfish Acanthaster planci, glycerol-peptone-yeast extract (GlyPY) and glucose-peptone-yeast extract (GluPY) media were used to culture this fungus. When cultured in GlyPY medium, this fungus produced two novel diketopiperazines, neosartins A and B (1 and 2), together with six biogenetically-related known diketopiperazines,1,2,3,4-tetrahydro-2, 3-dimethyl-1,4-dioxopyrazino[1,2-a]indole (3), 1,2,3,4-tetrahydro-2-methyl-3-methylen e-1,4-dioxopyrazino[1,2-a]indole (4), 1,2,3,4-tetrahydro-2-methyl-1,3,4-trioxopyrazino[1,2-a] indole (5), 6-acetylbis(methylthio)gliotoxin (10), bisdethiobis(methylthio)gliotoxin (11), didehydrobisdethiobis(methylthio)gliotoxin (12) and N-methyl-1H-indole-2-carboxamide (6). However, a novel tetracyclic-fused alkaloid, neosartin C (14), a meroterpenoid, pyripyropene A (15), gliotoxin (7) and five known gliotoxin analogues, acetylgliotoxin (8), reduced gliotoxin (9), 6-acetylbis(methylthio)gliotoxin (10), bisdethiobis(methylthio) gliotoxin (11) and bis-N-norgliovictin (13), were obtained when grown in glucose-containing medium (GluPY medium). This is the first report of compounds 3, 4, 6, 9, 10 and 12 as naturally occurring. Their structures were determined mainly by MS, 1D and 2D NMR data. The possible biosynthetic pathways of gliotoxin-related analogues and neosartin C were proposed. The antibacterial activity of compounds 2-14 and the cytotoxic activity of compounds 4, 5 and 7-13 were evaluated. Their structure-activity relationships are also preliminarily discussed.

Pseudaboydins A and B: novel isobenzofuranone derivatives from marine fungus Pseudallescheria boydii associated with starfish Acanthaster planci.

Two novel isobenzofuranone derivatives, pseudaboydins A (1) and B (2), along with five known compounds, including (R)-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-hydroxybenzofuran (3), (R)-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-methoxybenzofuran (4), 3,3'-dihydroxy-5,5'-dimethyldiphenyl ether (5), 3-(3-methoxy-5-methylphenoxy)-5-methylphenol (6) and (-)-regiolone (7), were isolated from the culture broth of the marine fungus, Pseudallescheria boydii, associated with the starfish, Acanthaster planci. Their structures were elucidated primarily based on NMR and MS data. The absolute configurations of 1-4 were determined by CD spectroscopy and single-crystal X-ray diffraction studies. The cytotoxic and antibacterial activities of 1-4 were evaluated. Pseudaboydin A (1) showed moderate cytotoxic activity against human nasopharyngeal carcinoma cell line HONE1, human nasopharyngeal carcinoma cell line SUNE1 and human glandular lung cancer cell line GLC82 with IC50 values of 37.1, 46.5 and 87.2 µM, respectively.

Violapyrones H and I, new cytotoxic compounds isolated from Streptomyces sp. associated with the marine starfish Acanthaster planci.

Two new α-pyrone derivatives, violapyrones H (1) and I (2), along with known violapyrones B (3) and C (4) were isolated from the fermentation broth of a marine actinomycete Streptomyces sp. The strain was derived from a crown-of-thorns starfish, Acanthaster planci, collected from Chuuk, Federated States of Micronesia. The structures of violapyrones were elucidated by the analysis of 1D and 2D NMR and HR-ESIMS data. Violapyrones (1-4) exhibited cytotoxicity against 10 human cancer cell lines with GI50 values of 1.10-26.12 µg/mL when tested using sulforhodamine B (SRB) assay. This is the first report on the cytotoxicity of violapyrones against cancer cell lines and the absolute configuration of violapyrone C.

Pseudoalteromonas xishaensis sp. nov., isolated from Acanthaster planci in the Xisha islands.

A Gram-negative, aerobic, motile by means of single polar flagellum, short rod-shaped marine bacterium, designated strain E418T, was isolated from the spines on the body surface of starfish Acanthaster planci in the Xisha islands, China. Cells of strain E418T were found to grow optimally at pH 7­8, at 25­37 °C, and in the presence of 2­5 % (w/v) NaCl. Phylogenetic analysis based on the comparison of 16S rRNA gene sequences revealed that strain E418T is a member of the genus Pseudoalteromonas. The closest relative to this strain was found to be P. ruthenica LMG 19699T, with a similarity level of 97.7 %. DNA relatedness between the novel isolate and this phylogenetically related species was 57.4 %. Strain E418T decomposed Tween 80, gelatin, and casein, but was unable to decompose starch and grow on DNase Agar. The cellular fatty acid profile consisted of significant amounts of C16:1ω7c/C16:1ω6c, C18:1ω7c/C18:1ω6c, C16:0, and C17:1ω8c. The G+C content of DNA of this strain was determined to be 46.7 mol%. Phenotypic characteristics, phylogenetic analysis and DNA­DNA relatedness data suggest that strain E418T represents a novel species of the genus Pseudoalteromonas, for which the name Pseudoalteromonas xishaensis sp. nov. is proposed. The type strain of P. xishaensis is strain E418T (DSM 25588T = NBRC 108846T = CCTCC AB 2011177T).

Trichodermaerin, a new diterpenoid lactone from the marine fungus Trichoderma erinaceum associated with the sea star Acanthaster planci.

Trichodermaerin (1), a novel diterpenoid lactone, together with the known compound, harziandione (2) were isolated from the culture broth of the fungus Trichoderma erinaceum associated with the sea star Acanthaster planci. Their structures were determined by analysis of the NMR and MS data. 1 was the Baeyer-Villiger monooxygenase catalyzed oxidation product of 2. Compound 2 did not show cytotoxic activities against various cancer cell lines.