Genome-guided discovery of two undescribed 6,6-spiroketal polyketides and stereochemical correction of bafilomycins P and Q from the marine-derived Streptomyces sp. SCSIO 66814.

Bafilomycins are macrocyclic polyketides with intriguing structures and therapeutic value. Genomic analysis of Streptomyces sp. SCSIO 66814 revealed a type I polyketide synthase biosynthetic gene cluster (BGC), namely blm, which encoded bafilomycins and featured rich post-modification genes.

Peniditerpenoids A and B: Oxidized Indole Diterpenoids with Osteoclast Differentiation Inhibitory Activity from a Mangrove-Sediment-Derived sp.

An unprecedented di--indole diterpenoid, peniditerpenoid A (), and a rare -oxide-containing indole diterpenoid derivative, peniditerpenoid B (), together with three known ones (-), were obtained from the mangrove-sediment-derived fungus sp. SCSIO 41411. Their structures were determined by the analysis of spectroscopic data, quantum chemical calculations, and X-ray diffraction analyses.

Resistance of an intertidal oyster(Saccostrea mordax)to marine heatwaves and the implication for reef building.

Marine heatwaves (MHWs) have a significant impact on intertidal bivalves and the ecosystems they sustain, causing the destruction of organisms' original habitats. Saccostrea mordax mainly inhabits the intertidal zone around the equator, exhibiting potential tolerance to high temperatures and maybe a species suitable for habitat restoration. However, an understanding about the tolerance mechanism of S.

Small molecule deoxynyboquinone triggers alkylation and ubiquitination of Keap1 at Cys489 on Kelch domain for Nrf2 activation and inflammatory therapy.

Activation of nuclear factor erythroid 2-related factor 2 (Nrf2) by Kelch-like ECH-associated protein 1 (Keap1) alkylation plays a central role in anti-inflammatory therapy. However, activators of Nrf2 through alkylation of Keap1-Kelch domain have not been identified. Deoxynyboquinone (DNQ) is a natural small molecule discovered from marine actinomycetes.

Nanoplastics impair growth and nitrogen fixation of marine nitrogen-fixing cyanobacteria.

Nanoplastics pollution is a growing environmental problem worldwide. Recent research has demonstrated the toxic effects of nanoplastics on various marine organisms. However, the influences of nanoplastics on marine nitrogen-fixing cyanobacteria, a critical nitrogen source in the ocean, remained unknown.

In Situ Electrochemical Synthesis of Squamous-like CuS Induced by Sulfate-Reducing Bacteria as a Fenton-like Catalyst in Wastewater Treatment: Catalytic Performance and Mechanism.

In this paper, a novel method was proposed for the synthesis of CuS on copper mesh via electrolysis in SRB culture medium. It was found that following electrolysis in SRB medium, squamous-like CuS arrays were obtained on the copper mesh, and the CuS loading contents varied with the electrolyzing parameters. The resultant CuS on copper mesh in SRB (CSCM-SRB) with the highest catalytic MB degradation properties was produced by electrolysis at 3.

Evolution of groundwater system in the Pearl River Delta and its adjacent shelf since the late Pleistocene.

Our extensive field studies demonstrate that saline groundwater inland and freshened groundwater offshore coexist in the same aquifer system in the Pearl River delta and its adjacent shelf. This counterintuitive phenomenon challenges the commonly held assumption that onshore groundwater is typically fresh, while offshore groundwater is saline. To address this knowledge gap, we conduct a series of sophisticated paleo-hydrogeological models to explore the formation mechanism and evolution process of the groundwater system in the inland-shelf systems.

Five million years of Antarctic Circumpolar Current strength variability.

The Antarctic Circumpolar Current (ACC) represents the world's largest ocean-current system and affects global ocean circulation, climate and Antarctic ice-sheet stability. Today, ACC dynamics are controlled by atmospheric forcing, oceanic density gradients and eddy activity. Whereas palaeoceanographic reconstructions exhibit regional heterogeneity in ACC position and strength over Pleistocene glacial-interglacial cycles, the long-term evolution of the ACC is poorly known.

New Phenol Derivatives from the Haima Cold Seep-Derived Fungus CYH-17.

Seven new phenol derivatives, subversins A-E (-), subversic acid A () and -wortmannine G (); one new natural product, 4-hydroxy-7-methoxyphthalide (); and five known compounds (-) were isolated from the fungus CYH-17 collected from the Haima cold seep. The structures and absolute configurations of these compounds were determined via NMR, MS, optical rotation, electronic circular dichroism (ECD) calculation, X-ray diffraction analysis and comparison with the literature. Compounds and were two pairs of enantiomers.

Two New Sesquiterpenoids and a New Shikimic Acid Metabolite from Mangrove Sediment-Derived Fungus sp. SCSIO 41427.

Two new sesquiterpenoid derivatives, elgonenes M () and N (), and a new shikimic acid metabolite, methyl 5--acetyl-5--shikimate (), were isolated from the mangrove sediment-derived fungus sp. SCSIO 41427 together with fourteen known compounds (-). The planar structures were elucidated through nuclear magnetic resonance (NMR) and mass spectroscopic (MS) analyses.

Potential Function of 3,5-Dihydroxy-4-Methoxybenzyl Alcohol from Pacific Oyster (Crassostrea gigas) in Brain of Old Mice.

Scope: 3,5-Dihydroxy-4-methoxybenzyl alcohol (DHMBA) is found in oyster extracts in recent years and is reported to have antioxidant activity. Although it has been reported to be protective in various models of oxidative stress, the therapeutic effect of DHMBA on neurological damage caused by aging remains to be demonstrated.

Methods And Results: The present study investigates the potential functions of DHMBA in brain of old C57BL/6J mice and aging cell model.

First Evidence of the Bioaccumulation and Trophic Transfer of Tire Additives and Their Transformation Products in an Estuarine Food Web.

The discovery of the significant lethal impacts of the tire additive transformation product -(1,3-dimethylbutyl)-'-phenyl--phenylenediamine quinone (6PPD-Q) on coho salmon has garnered global attention. However, the bioaccumulation and trophic transfer of tire additives and their transformation products (TATPs) within food webs remain obscure. This study first characterized the levels and compositions of 15 TATPs in the Pearl River Estuary, estimated their bioaccumulation and trophic transfer potential in 21 estuarine species, and identified priority contaminants.

Combining CRISPR/Cas9 and natural excision for the precise and complete removal of mobile genetic elements in bacteria.

Horizontal gene transfer, facilitated by mobile genetic elements (MGEs), is an adaptive evolutionary process that contributes to the evolution of bacterial populations and infectious diseases. A variety of MGEs not only can integrate into the bacterial genome but also can survive or even replicate like plasmids in the cytoplasm, thus requiring precise and complete removal for studying their strategies in benefiting host cells. Existing methods for MGE removal, such as homologous recombination-based deletion and excisionase-based methods, have limitations in effectively eliminating certain MGEs.

Biological soil crust elicits microbial community and extracellular polymeric substances restructuring to reduce the soil erosion on tropical island, South China Sea.

Soil erosion stands as the preeminent environmental concern globally, attaining heightened significance, particularly within islands where land resources prove notably scarce. Biological soil crusts, referred to as biocrusts, assume a pivotal ecological role in soil conservation. Notably, they augment the horizontal stability of the substrate through the exudation of microbial extracellular polymeric substances (EPS), thereby shielding the soil against shear stress, exemplified in the form of water erosion.

New Antibacterial Peptaibiotics against Plant and Fish Pathogens from the Deep-Sea-Derived Fungus EIODSF 020.

Bacterial diseases could severely harm agricultural production. To develop new antibacterial agents, the secondary metabolites of a deep-sea-derived fungus EIODSF 020 with antibacterial activities against plant and fish pathogens were investigated by a bioassay-guided approach, which led to the isolation of 11 new peptaibiotics, simplicpeptaibs A-K (-). They contain 16-19 residues, including β-alanine, tyrosine, or tyrosine -sulfate, that were rarely present in peptaibiotics.

Gene expression of Pocillopora damicornis coral larvae in response to acidification and ocean warming.

Objectives: The endosymbiosis with Symbiodiniaceae is key to the ecological success of reef-building corals. However, climate change is threatening to destabilize this symbiosis on a global scale. Most studies looking into the response of corals to heat stress and ocean acidification focus on coral colonies.

An Enzymatic Carbon-Carbon Bond Cleavage and Aldol Reaction Cascade Converts an Angular Scaffold into the Linear Tetracyclic Core of Ochraceopones.

Meroterpenoids of the ochraceopones family featuring a linear tetracyclic scaffold exhibit exceptional antiviral and anti-inflammatory activities. The biosynthetic pathway and chemical logic to generate this linear tetracycle, however, remain unknown. In this study, we identified and characterized all biosynthetic enzymes to afford ochraceopones and elucidated the complete biosynthetic pathway.

Identification and involvement of DAX1 gene in spermatogenesis of boring giant clam Tridacna crocea.

DAX1 (dosage-sensitive sex reversal, adrenal hypoplasia congenital critical region on X chromosome gene 1), a key sex determinant in various species, plays a vital role in gonad differentiation and development and controls spermatogenesis. However, the identity and function of DAX1 are still unclear in bivalves. In the present study, we identified a DAX1 (designed as Tc-DAX1) gene from the boring giant clam Tridacna crocea, a tropical marine bivalve.

Linking coral fluorescence phenotypes to thermal bleaching in the reef-building from the northern South China Sea.

Unlabelled: Coral fluorescence phenotypes have been suggested as an adaptation to a broad range of environmental conditions, yet the mechanisms linking thermal bleaching tolerance in reef-building coral populations, associated with fluorescence phenotypes due to GFP-like proteins, remains unclear. In this study, the relationship between the thermal sensitivity and phenotypic plasticity of corals was investigated using two phenotypes of green and brown. The results reveal that brown was more susceptible to bleaching than green when exposed to a higher growth temperature of 32 °C.

Microascones, Decahydrofluorene-Class Alkaloids from the Marine-Derived Fungus sp. SCSIO 41821.

Eight new decahydrofluorene-class alkaloids, microascones A and B ( and ), 2,3-epoxyphomapyrrolidone C (), 14,16-epiascomylactam B (), 24-hydroxyphomapyrrolidone A (), and microascones C-E (-), along with five known analogs (-) were isolated from the marine-derived fungus sp. SCSIO 41821. Compounds and have an unprecedented complex macrocyclic alkaloid skeleton with a 6/5/6/5/6/5/13 polycyclic system.

Increased light intensity enhances photosynthesis and biochemical components of red macroalga of commercial importance, Kappaphycus alvarezii, in response to ocean acidification.

The concentration of atmospheric carbon dioxide (CO) has increased drastically over the past several decades, resulting in the pH of the ocean decreasing by 0.44 ± 0.005 units, known as ocean acidification (OA).

HPPO-Derived Meroterpenoids from the Marine-Derived Fungus sp. SCSIO 41691.

Seven new 4-hydroxy-6-phenyl-2-pyran-2-one (HPPO) derived meroterpenoids, 1-methyl-12a,12b-epoxyarisugacin M (), 1-methyl-4a,12b-epoxyarisugacin M (), 2,3-dihydroxy-3,4a-epoxy-12a-dehydroxyisoterreulactone A (), 2-hydroxy-12a-dehydroxyisoterreulactone A (), 3'-demethoxyterritrems B' (), 4a-hydroxyarisugacin P (), and 1-epi-arisugacin H (), together with two known analogues ( and ), were isolated from the marine-derived fungal strain sp. SCSIO 41691. Their structures were elucidated by spectroscopic methods, and the absolute configurations of compounds and were determined by single-crystal X-ray diffraction.

Reconstruction of Long-Chain Polyunsaturated Acid Synthesis Pathways in Marine Red Microalga Using Lipidomics and Transcriptomics.

The marine red microalga can simultaneously synthesize long-chain polyunsaturated fatty acids, including eicosapentaenoic acid (C20:5, EPA) and arachidonic acid (C20:4, ARA). However, the distribution and synthesis pathways of EPA and ARA in are not clearly understood. In this study, CCALA 415 was cultured in nitrogen-replete and nitrogen-limited conditions.

Diversified Chemical Structures and Bioactivities of the Chemical Constituents Found in the Brown Algae Family Sargassaceae.

Sargassaceae, the most abundant family in Fucales, was recently formed through the merging of the two former families Sargassaceae and Cystoseiraceae. It is widely distributed in the world's oceans, notably in tropical coastal regions, with the exception of the coasts of Antarctica and South America. Numerous bioactivities have been discovered through investigations of the chemical diversity of the Sargassaceae family.

Slc43a2 T cell metastasis from spleen to brain in RGNNV infected teleost.

The origin of T cells in the teleost's brain is unclear. While viewing the central nervous system (CNS) as immune privileged has been widely accepted, previous studies suggest that T cells residing in the thymus but not in the spleen of the teleost play an essential role in communicating with the peripheral organs. Here, we identified nine T cell subpopulations in the thymus and spleen of orange-spotted grouper (Epinephelus coioices) through single-cell RNA-sequencing analysis.