Metagenomics Reveals Microbial Diversity and Metabolic Potentials of Seawater and Surface Sediment From a Hadal Biosphere at the Yap Trench

Hadal biosphere represents the deepest part of the ocean with water depth >6,000 m. Accumulating evidence suggests the existence of unique microbial communities dominated by heterotrophic processes in this environment. However, investigations of the microbial diversity and their metabolic potentials are limited because of technical constraints for sample collection. Here, we provide a detailed metagenomic analysis of three seawater samples at water depths 5,000–6,000 m below sea level (mbsl) and three surface sediment samples at water depths 4,435–6,578 mbsl at the Yap Trench of the western Pacific. Distinct microbial community compositions were observed with the dominance of Gammaproteobacteria in seawater and Thaumarchaeota in surface sediment. Comparative analysis of the genes involved in carbon, nitrogen and sulfur metabolisms revealed that heterotrophic processes (i.e., degradation of carbohydrates, hydrocarbons, and aromatics) are the most common microbial metabolisms in the seawater, while chemolithoautotrophic metabolisms such as ammonia oxidation with the HP/HB cycle for CO2 fixation probably dominated the surface sediment communities of the Yap Trench. Furthermore, abundant genes involved in stress response and metal resistance were both detected in the seawater and sediments, thus the enrichment of metal resistance genes is further hypothesized to be characteristic of the hadal microbial communities. Overall, this study sheds light on the metabolic versatility of microorganisms in the Yap Trench, their roles in carbon, nitrogen, and sulfur biogeochemical cycles, and how they have adapted to this unique hadal environment

Cytotoxic and Antibacterial Compounds from the Coral-Derived Fungus Aspergillus tritici SP2-8-1

Three novel compounds, 4-methyl-candidusin A (1), aspetritone A (2) and aspetritone B (3), were obtained from the culture of a coral-derived fungus Aspergillus tritici SP2-8-1, together with fifteen known compounds (4–18). Their structures, including absolute configurations, were assigned based on NMR, MS, and time-dependent density functional theory (TD-DFT) ECD calculations. Compounds 2 and 5 exhibited better activities against methicillin-resistant strains of S. aureus (MRSA) ATCC 43300 and MRSA CGMCC 1.12409 than the positive control chloramphenicol. Compound 5 displayed stronger anti-MRSA and lower cytotoxic activities than 2, and showed stronger antibacterial activities against strains of Vibrio vulnificus, Vibrio rotiferianus, and Vibrio campbellii than the other compounds. Compounds 2 and 10 exhibited significantly stronger cytotoxic activities against human cancer cell lines HeLa, A549, and Hep G2 than the other compounds. Preliminary structure–activity relationship studies indicated that prenylation of terphenyllin or candidusin and the tetrahydrobenzene moiety in anthraquinone derivatives may influence their bioactivity

Two new meroterpenoids and two new monoterpenoids from the deep sea-derived fungus Penicillium sp. YPGA11

Twelve terpenoids, including two new 3,5-dimethylorsellinic acid-based meroterpenoids (1 and 2) and two new monoterpenoids (11 and 12), were obtained from the deep-sea fungus Penicillium sp. YPGA11. Their structures were determined by extensive analyses of spectroscopic data, and the absolute configurations of 1 and 2 were determined by comparisons of experimental and calculated ECD spectra. Compounds 1 and 2, bearing a 23-aldehyde or 23-carboxylic acid group, were rarely found in compounds with similar carbon skeleton. All compounds but 11 were evaluated for inhibitory effects towards nitric oxide production induced by lipopolysaccharide in RAW 264.7 macrophage cells. Compound 9 exhibited significant inhibitory effects with an IC50 value of 7.58 μM, being comparable to the positive control, quercetin (10.97 μM)

Antimicrobial activity and molecular docking studies of a novel anthraquinone from a marine-derived fungus <i>Aspergillus versicolor</i>

<p>A novel anthraquinone, 2-(dimethoxymethyl)-1-hydroxyanthracene-9,10-dione (<b>1</b>), together with nine known compounds (<b>2</b>–<b>10</b>), were isolated from the fermentation of <i>Aspergillus versicolor</i> derived from deep sea sediment. Their structures were established through spectroscopic methods. Compound <b>1</b> exhibited strong inhibitory activities against MRSA ATCC 43300 and MRSA CGMCC 1.12409 (with MIC values of 3.9 and 7.8 μg/mL respectively) and moderate activities against tested strains of <i>Vibrio</i> (with MIC values ranging from 15.6 to 62.5 μg/mL). Compound <b>1</b> was subjected to molecular docking studies for inhibition of topoisomerase IV and AmpC <i>β</i>-lactamase enzymes indicating its usefulness as antimicrobial agent.</p

Butenolide Derivatives with α-Glucosidase Inhibitions from the Deep-Sea-Derived Fungus Aspergillus terreus YPGA10

Three new butenolide derivatives, namely aspernolides N&ndash;P (1&ndash;3), together with six known analogues (4&ndash;9), were isolated from the ethyl acetate (EtOAc) extract of the deep sea-derived fungus Aspergillus terreus YPGA10. The structures of compounds 1&ndash;3 were determined on the basis of comprehensive analyses of the nuclear magnetic resonance (NMR) and mass spectroscopy (MS) data, and the absolute configurations of 1 and 2 were determined by comparisons of experimental electronic circular dichroism (ECD) with calculated ECD spectra. Compound 1 represents the rare example of Aspergillus-derived butenolide derivatives featured by a monosubstituted benzene ring. Compounds 6&ndash;9 exhibited remarkable inhibitory effects against &alpha;-glucosidase with IC50 values of 3.87, 1.37, 6.98, and 8.06 &mu;M, respectively, being much more active than the positive control acarbose (190.2 &mu;M)

Peniginsengins B–E, New Farnesylcyclohexenones from the Deep Sea-Derived Fungus Penicillium sp. YPGA11

Chemical examination of the EtOAc extract of the deep sea-derived fungus Penicillium sp. YPGA11 resulted in the isolation of four new farnesylcyclohexenones, peniginsengins B–E (1–4), and a known analog peniginsengin A (5). The structures of compounds 1–4 were determined on the basis of comprehensive analyses of the nuclear magnetic resonance (NMR) and mass spectroscopy (MS) data, and the absolute configurations of 1, 2, and 4 were determined by comparisons of experimental electronic circular dichroism (ECD) with calculated ECD spectra. Compounds 1–5, characterized by a highly oxygenated 1-methylcyclohexene unit and a (4E,8E)-4,8-dimethyldeca-4,8-dienoic acid side chain, are rarely found in nature. Compounds 2–4 exhibited antibacterial activity against Staphylococcus aureus