Absolute structures and bioactivities of euryspongins and eurydiene obtained from the marine sponge Euryspongia sp. collected at Iriomote Island

Marine Sponge Endosymbionts: Structural and Functional Specificity of the Microbiome within Euryspongia arenaria Cells

Sponge microbiomes are typically profiled by analyzing the community DNA of whole tissues, which does not distinguish the taxa residing within sponge cells from extracellular microbes. To uncover the endosymbiotic microbiome, we separated the sponge cells to enrich the intracellular microbes. The intracellular bacterial community of sponge Euryspongia arenaria was initially assessed by amplicon sequencing, which indicated that it hosts three unique phyla not found in the extracellular and bulk tissue microbiomes. These three phyla account for 66% of the taxonomically known genera in the intracellular microbiome. The shotgun metagenomic analysis extended the taxonomic coverage to viruses and eukaryotes, revealing the most abundant signature taxa specific to the intracellular microbiome. Functional KEGG pathway annotation demonstrated that the endosymbiotic microbiome hosted the greatest number of unique gene orthologs. The pathway profiles distinguished the intra- and extracellular microbiomes from the tissue and seawater microbiomes. Carbohydrate-active enzyme analysis further discriminated each microbiome based on their representative and dominant enzyme families. One pathway involved in digestion system and family esterase had a consistently higher level in intracellular microbiome and could statistically differentiate the intracellular microbiome from the others, suggesting that triacylglycerol lipases could be the key functional component peculiar to the endosymbionts. The identified higher abundance of lipase-related eggNOG categories further supported the lipid-hydrolyzing metabolism of endosymbiotic microbiota. Pseudomonas members, reported as lipase-producing bacteria, were only in the endosymbiotic microbiome, meanwhile Pseudomonas also showed a greater abundance intracellularly. Our study aided a comprehensive sponge microbiome that demonstrated the taxonomic and functional specificity of endosymbiotic microbiota.

IMPORTANCE Sponges host abundant microbial symbionts that can produce an impressive number of novel bioactive metabolites. However, knowledge on intracellular (endosymbiotic) microbiota is scarce. We characterize the composition and function of the endosymbiotic microbiome by separation of sponge cells and enrichment of intracellular microbes. We uncover a noteworthy number of taxa exclusively in the endosymbiotic microbiome. We unlock the unique pathways and enzymes of endosymbiotic taxa. This study achieves a more comprehensive sponge microbial community profile, which demonstrates the structural and functional specificity of the endosymbiotic microbiome. Our findings not only open the possibility to reveal the low abundant and the likely missed microbiota when directly sequencing the sponge bulk tissues, but also warrant future in-depth exploration within single sponge cells.

Exploration of marine natural resources in Indonesia and development of efficient strategies for the production of microbial halogenated metabolites

Nature is a prolific source of organic products with diverse scaffolds and biological activities. The process of natural product discovery has gradually become more challenging, and advances in novel strategic approaches are essential to evolve natural product chemistry. Our focus has been on surveying untouched marine resources and fermentation to enhance microbial productive performance. The first topic is the screening of marine natural products isolated from Indonesian marine organisms for new types of bioactive compounds, such as antineoplastics, antimycobacterium substances, and inhibitors of protein tyrosine phosphatase 1B, sterol O-acyl-transferase, and bone morphogenetic protein-induced osteoblastic differentiation. The unique biological properties of marine organohalides are discussed herein and attempts to efficiently produce fungal halogenated metabolites are documented. This review presents an overview of our recent work accomplishments based on the MONOTORI study.

Extracting value: mechanistic insights into the formation of natural product artifacts – case studies in marine natural products

This review highlights the importance of valuing natural product handling artifacts, to open a new window into, and provide a unique perspective of, bioactive chemical space.

Marine Pharmacology in 2014-2015: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis, Antiviral, and Anthelmintic Activities; Affecting the Immune and Nervous Systems, and Other Miscellaneous Mechanisms of Action

The systematic review of the marine pharmacology literature from 2014 to 2015 was completed in a manner consistent with the 1998-2013 reviews of this series. Research in marine pharmacology during 2014-2015, which was reported by investigators in 43 countries, described novel findings on the preclinical pharmacology of 301 marine compounds. These observations included antibacterial, antifungal, antiprotozoal, antituberculosis, antiviral, and anthelmintic pharmacological activities for 133 marine natural products, 85 marine compounds with antidiabetic, and anti-inflammatory activities, as well as those that affected the immune and nervous system, and 83 marine compounds that displayed miscellaneous mechanisms of action, and may probably contribute to novel pharmacological classes upon further research. Thus, in 2014-2015, the preclinical marine natural product pharmacology pipeline provided novel pharmacology as well as new lead compounds for the clinical marine pharmaceutical pipeline, and thus continued to contribute to ongoing global research for alternative therapeutic approaches to many disease categories.

[Search for Protein Tyrosine Phosphatase 1B Inhibitors from Marine Organisms and Induced Production of New Fungal Metabolites by Modulating Culture Methods]

Marine environments offer a rich source of natural products with potential therapeutic applications because the ocean covers 70% of the earth's surface and approximately 80% of all living organisms live in the sea. Therefore we have investigated bioactive compounds from marine organisms such as marine sponges, ascidians, and marine-derived microorganisms. This review consists of two topics based on marine natural product chemistry. (1) Protein tyrosine phosphatase (PTP) 1B plays a key role as a negative regulator in the insulin and leptin signaling pathways. Accordingly, the development of PTP1B inhibitors is expected to provide new drugs for type 2 diabetes and obesity. We have been searching for new types of PTP1B inhibitors among marine organisms and identified various PTP1B inhibitors from marine sponges and fungi. This review presents their structural diversities and unique biological properties. (2) In the course of our studies on the induced production of new fungal metabolites, the Palauan marine-derived fungus, Trichoderma cf. brevicompactum TPU199, was found to produce the unusual epipolythiodiketopiperazines, gliovirin and pretrichodermamide A. Long-term static fermentation of the strain induced production of a new dipeptide, dithioaspergillazine A, whereas fermentation of the strain with NaCl, NaBr, and NaI produced the Cl and Br derivatives of pretrichodermamide A and a new iodinated derivative, iododithiobrevamide, respectively. Moreover, DMSO-added seawater medium induced the production of diketopiperazine with the unprecedented trithio-bridge, chlorotrithiobrevamide. This fermentation study on the strain as well as the structures of the metabolites obtained are described in this review.

Lamellodysidines A and B, Sesquiterpenes Isolated from the Marine Sponge Lamellodysidea herbacea

Four new sesquiterpenes, lamellodysidines A and B, O,O-dimethyllingshuiolide A, and 11-epi-O,O-dimethyllingshuiolide A (1-4), were obtained from the marine sponge, Lamellodysidea herbacea, collected in Indonesia. Their planar structures were elucidated by analysis of spectroscopic data. The absolute configurations of the new compounds were determined by the calculated ECD spectra. Compound 1 has a unique carbon framework, and 2 is a new nitrogenous sesquiterpene.

Marine natural products

Covering: 2015. Previous review: Nat. Prod. Rep., 2016, 33, 382-431This review covers the literature published in 2015 for marine natural products (MNPs), with 1220 citations (792 for the period January to December 2015) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1340 in 429 papers for 2015), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

Metabolic Disorder in Chronic Obstructive Pulmonary Disease (COPD) Patients: Towards a Personalized Approach Using Marine Drug Derivatives

Metabolic disorder has been frequently observed in chronic obstructive pulmonary disease (COPD) patients. However, the exact correlation between obesity, which is a complex metabolic disorder, and COPD remains controversial. The current study summarizes a variety of drugs from marine sources that have anti-obesity effects and proposed potential mechanisms by which lung function can be modulated with the anti-obesity activity. Considering the similar mechanism, such as inflammation, shared between obesity and COPD, the study suggests that marine derivatives that act on the adipose tissues to reduce inflammation may provide beneficial therapeutic effects in COPD subjects with high body mass index (BMI).

Sesquiterpene Hydroquinones with Protein Tyrosine Phosphatase 1B Inhibitory Activities from a Dysidea sp. Marine Sponge Collected in Okinawa

Three new sesquiterpene hydroquinones, avapyran (1), 17-O-acetylavarol (2), and 17-O-acetylneoavarol (3), were isolated from a Dysidea sp. marine sponge collected in Okinawa together with five known congeners: avarol (4), neoavarol (5), 20-O-acetylavarol (6), 20-O-acetylneoavarol (7), and 3'-aminoavarone (8). The structures of 1-3 were assigned on the basis of their spectroscopic data. Compounds 1-3 inhibited the activity of protein tyrosine phosphatase 1B with IC50 values of 11, 9.5, and 6.5 μM, respectively, while known compounds 4-8 gave IC50 values of 12, >32, 10, 8.6, and 18 μM, respectively. In a preliminary investigation on structure-activity relationships, six ester and methoxy derivatives (9-14) were prepared from 4 and 5.

Strongylophorines, new protein tyrosine phosphatase 1B inhibitors, from the marine sponge Strongylophora strongilata collected at Iriomote Island

A new meroditerpene, 26-O-ethylstrongylophorine-14 (1), was isolated from the Okinawan marine sponge Strongylophora strongilata together with six known strongylophorines: 26-O-methylstrongylophorine-16 (2) and strongylophorines-2 (3), -3 (4), -8 (5), -15 (6), and -17 (7). The structure of 1 was assigned on the basis of its spectroscopic data. Compound 1 inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with an IC50 value of 8.7 μM, while known compounds 2-8 gave IC50 values of 8.5, >24.4, 9.0, 21.2, 11.9, and 14.8 μM, respectively. Oleanolic acid, a positive control, inhibited PTP1B activity at 0.7 μM (IC50). The inhibitory activities of strongylophorines possessing the acetal moiety at C-26 (1, 2, and 6) were stronger than those of the lactone derivatives (3 and 5). This is the first study to demonstrate that meroditerpenes inhibit PTP1B activity.

Structures and Biological Evaluations of Agelasines Isolated from the Okinawan Marine Sponge Agelas nakamurai

Three new N-methyladenine-containing diterpenes, 2-oxoagelasines A (1) and F (2) and 10-hydro-9-hydroxyagelasine F (3), were isolated from the Okinawan marine sponge Agelas nakamurai Hoshino together with eight known agelasine derivatives, 2-oxoagelasine B (4), agelasines A (5), B (6), D (7), E (8), F (9), and G (10), and ageline B (11). The structures of 1-3 were assigned on the basis of their spectroscopic data and their comparison with those of the literature. Compounds 3 and 5-11 inhibited the growth of Mycobacterium smegmatis with inhibition zones of 10, 14, 15, 18, 14, 20, 12, and 12 mm at 20 μg/disc, respectively. All compounds were inactive (IC50 > 10 μM) against Huh-7 (hepatoma) and EJ-1 (bladder carcinoma) human cancer cell lines. Three 2-oxo derivatives (1, 2, and 4) exhibited markedly reduced biological activity against M. smegmatis. Moreover, compound 10 inhibited protein tyrosine phosphatase 1B (PTP1B) activity with an IC50 value of 15 μM.

Trichoketides A and B, two new protein tyrosine phosphatase 1B inhibitors from the marine-derived fungus Trichoderma sp

Two new octaketides, trichoketides A (1) and B (2), were isolated from a culture broth of the seawater-derived fungus Trichoderma sp. TPU1237 together with two known analogs, trichodermaketones C (3) and D (4), by ODS column chromatography followed by preparative ODS and chiral HPLC. The structures of 1 and 2 were elucidated on the basis of their spectroscopic data, and absolute configurations were assigned by comparing their experimental electronic circular dichroism (ECD) spectra with the calculated ECD spectra. Compounds 1 and 2 were epimers at the C-8 position (α-position of dihydrofuran ring). The IC50 values of compounds 1-4 against protein tyrosine phosphatase 1B were 53.1, 65.1, 68.0 and 55.9 μM, respectively.