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Antifouling Potentials and Metabolite Profiles of Two Marine-derived Fungal Isolates
No full textExtracts of the culture broths of Aspergillus sydowii SCSIO 00305 and Penicillium chrysogenum SCSIO 00258 exhibited a relatively broad spectrum of antifouling activity against various biofoulers. The main chemical components of their bioactive fractions were analyzed and identified by LC-MS and from literature data. Two bioactive fractions comprised of 1 alpha-methoxyroquefortine C, meleagrin, roquefortine C and isoroquefortine C exhibited more significant anti-barnacle activity than meleagrin in field bioassays, suggesting that the combination of different bioactive compounds could display a stronger antifouling activity than a single compound in the complicated marine ecological environments
Involvement of eIF2 alpha of Epinephelus coioides in the fish immune response to virus infection
No full textThe eukaryotic initiation factor 2 alpha subunit (eIF2 alpha) is a key translation regulator that plays an important role in different cellular pressures and stimuli, including virus infection. In the present study, an eIF2 alpha homolog (EcelF2 alpha) from the orange-spotted grouper (Epinephelus coioides) was cloned and its roles during fish viral infection were characterized. EcelF2 alpha encodes a putative protein of 315 amino acid residues, and shares a high degree of similarity with elF2 alpha s from other species. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that EcelF2 alpha was distributed in all examined tissues. Both of the expression levels of EceIF2 alpha in the spleen and head kidney of E. coioides were up-regulated when challenged with polyinosine-polycytidylic acid (poly[I:C]). EceIF2 alpha was abundantly distributed in both the cytoplasm and nucleus in grouper spleen (GS) cells. Over-expression of EceIF2 alpha improved the expression of red-spotted grouper nervous necrosis virus (RGNNV) genes in GS cells. In addition, EceIF2 alpha depressed the activation of NK-kappa B and IFN-beta. Furthermore, dephosphorylation inhibitor treatment led to a significant decrease of RGNNV gene transcription. Taken together, these results suggest that EcelF2 alpha might be involved in the fish immune response to virus challenge
Contrasting patterns of freshwater microbial metabolic potentials and functional gene interactions between an acidic mining lake and a weakly alkaline lake
No full textAcidic coal mining lakes (AMLs) are characterized by low pH, low biodiversity, and high concentrations of sulfate and metals. However, to date, knowledge is inadequate on the involvement of the aquatic microbial functions in biogeochemical processes of an AML. Here, we use a natural weakly alkaline lake (WAL) as a reference to investigate the functional gene structure of microbial communities in the aerobic surface waters of an AML by using a metagenomic approach with GeoChip-based functional gene arrays (GeoChip 5.0). We found significant differences in the compositions of the microbial functional genes between the two lake types. The AML had significantly lower gene diversity than the WAL, and the functional genes detected in the AML were almost a subset of those in the WAL. We also found significant differences in the microbial metabolic potentials between the two lake types. In the AML, the microbial communities had higher functional capacities in phosphorus-utilization, sulfur oxidation, and metal-detoxification and had lower metabolic potentials of carbon and nitrogen fixation, and the degradation of starch, hemicellulose, cellulose, chitin, and lignin than those in the WAL. By performing null model and network analyses, we observed stronger deterministic effects of the functional gene assemblages and greater clustering among the co-occurring functional genes in the AML than those in the WAL. Altogether, we demonstrated contrasting patterns of freshwater microbial metabolic potentials and functional gene interactions between an AML and a WAL, which may advance the understanding of microbial functional response to acidification in freshwater lakes
New chlorinated diphenyl ethers and xanthones from a deep-sea-derived I fungus Penicillium chrysogenum SCSIO 41001
No full textSeven new compounds, including four new chlorinated diphenyl ethers, namely chrysines A-D (1-4), one new dichlorinated xanthone, chrysoxanthone (5), dichloroorcinol (6), and one new benzeneacetic acid derivative, 3-isopentyl-4-hydroxy phenylacetic acid methyl ester (7), along with fourteen known compounds (8-21), were isolated from a deep-sea-derived fungus Penicillium chrysogenum SCSIO 41001. Their structures were determined by extensive spectroscopic methods and X-ray single-crystal diffraction analysis. All of the isolated compounds (1 - 21) were evaluated for their a-glucosidase inhibitory activity using PNPG method. Among them, nine compounds (2, 3, 5, 6, 8, 9, 13, 17, and 18) exhibited inhibitory activity against alpha-glucosidase with IC50 values of 0.35, 0.20, 0.04, 0.16, 0.15, 0.09, 0.14, 0.14, and 0.12 mM, respectively (IC50 0.28 mM for the positive control acarbose)
Arsenic biokinetics and bioavailability in deposit-feeding clams and polychaetes
No full textIn the present study, the arsenic (As) biokinetics and bioavailability in two deposit-feeding invertebrates (clams Gafrarium tumidum and polychaetes Nereis succinea) were quantified. Radiotracer techniques were applied to measure the dissolved uptake rate, dietary assimilation efficiency and efflux of As by the clams and polychaetes. Simultaneously, arsenic species analysis was conducted to examine the As biotransformation following dietary uptake. The radiotracer results showed that the uptake rate constant and efflux rate constant were 0.068 L/g/d and 0.07 d(-1), and 0.173 L/g/d and 0.09 d(-1), in the clams and polychaetes, respectively. Sediments labeled for different times (1.5-60 d) with different inorganic/organic As percentages led to diverse assimilation efficiencies of As (35.1-56.1% in the clams, and 51.6-72.6% in the polychaetes). Modeling calculations showed that sediment was a significant source for As bioaccumulation in the two deposit-feeders. After feeding on the spiked sediments, inorganic As (75.6%) was initially the predominant form, but arsenobetaine (AsB) became the predominant compound (>90%) in the clams and polychaetes during depuration, suggesting biotransformation of inorganic As. Combined with the biokinetics and biotransformation measurements, we showed that AsB was more efficiently assimilated and tended to be accumulated, whereas As(III) was less efficiently assimilated and more rapidly eliminated by the two invertebrates. This study demonstrated that As speciation in the sediments as a significant source for As bioaccumulation caused different bioavailability in deposit-feeding clams and polychaetes. (c) 2017 Elsevier B.V. All rights reserved
Identification and analysis of an MKK4 homologue in response to the nucleus grafting operation and antigens in the pearl oyster, Pinctada fucata
No full textThe mitogen-activated protein kinase kinase 4 (MKK4) is a key component of the c-Jun N-terminal kinase (JNK) signaling pathway and regulates multiple cellular activities. However, little is known about the roles of this kinase in pearl oyster. In this study, we identified an MKK4 homologue in Pinctada fucata by using a transcriptome database. Sequence analysis and protein structure prediction showed that PfMKK4 is highly conserved to MKK4 from other vertebrate and invertebrate species. Phylogenetic analysis revealed that PfMKK4 has the closest relationship with that from Crassostrea gigas. QPCR was used to investigate expression profiles in different healthy adult tissues and developmental stages of P. fucata. We found that PfMKK4 was ubiquitously expressed in all tissues and developmental stages examined except for in D-shaped larvae. Gene expression analysis suggested that PfMKK4 is involved in the response to the nucleus insertion operation. Lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid [poly(I:C)] stimulation in vivo reduced PfMKK4 mRNA expression at 6 h, 48 h and 48 h, 72 h, respectively. LPS and poly(I:C) induced PfMKK4 phosphorylation in a primary mantle cell culture. These results contribute to better understanding of the potential role played by PfMKK4 in protecting the pearl oyster from injury caused by grafting or disease
Grincamycins I-K, Cytotoxic Angucycline Glycosides Derived from Marine-Derived Actinomycete Streptomyces lusitanus SCSIO LR32
No full textThree new angucycline glycosides, designated grincamycin I ( 1 ), J ( 2 ), and K ( 3 ), together with the known congener A-7884 ( 4 ), were isolated from marine-derived actinomycete Streptomyces lusitanus SCSIO LR32. The structures of the new compounds were elucidated by comprehensive spectral data analysis. Compounds 2 and 4 exhibited antitumor activity against human cancer cells MDA-MB-435, MDA-MB-231, NCI-H460, HCT-116 and HepG2, and human normal breast epithelial cell MCF10A with IC (50) values ranging from 0.4 to 6.9 mu M. In addition, A-7884 ( 4 ) demonstrated antimicrobial activity against Micrococcus luteus with an MIC value of 1.95 mu g/mL
Genome mining of Streptomyces olivaceus SCSIO T05: Discovery of olimycins A and B and assignment of absolute configurations
No full textNaphthoquinone macrolides have attracted considerable synthetic interest due to their unique scaffolds, but there was no completion of total synthesis reported. In this study, genome mining and genetic manipulations were applied to stimulate the production of naphthoquinone macrolides from the deep-sea actinomycete Streptomyces olivaceus SCSIO T05; as a result, new metabolites olimycins A and B (1, 2) were isolated. The structures were elucidated on the basis of extensive spectroscopic data and X-ray single crystal diffraction studies. The results of these efforts enabled rectification of a key structural error made during previous efforts to characterize naphthoquinone macrolides. (C) 2017 Elsevier Ltd. All rights reserved
Antitubercular Marine Natural Products
No full textDue to the importance of nature as a source of new drug candidates, the purpose of this article is to emphasize the marine natural products, which exhibit antitubercular activity, published between January 2000 and May 2016, with 138 quotations to 250 compounds obtained from marine resources. These metabolites are organized by chemical constitution and named as simple alkyl lipids derivatives, aromatics derivatives, peptides, alkaloids, terpenoids, steroids, macrolides, and polycyclic polyketides
MicroRNA-146a promotes red spotted grouper nervous necrosis virus (RGNNV) replication by targeting TRAF6 in orange spotted grouper, Epinephelus coioides
No full textMicroRNA-146a (miR-146a) has been demonstrated to function as a negative regulator of cellular immune responses against pathogens in mammals, however, little information focused on its functions in lower vertebrates. In this study, we investigated the regulatory roles of orange spotted grouper, Epinephelus coioides miR-146a during red spotted grouper nervous necrosis virus (RGNNV) infection. During RGNNV infection in grouper spleen (GS) cells, the endogenous expression level of miR-146a and tumor necrosis factor receptor-associated factor 6 (TRAF6) significantly increased along with the infection time. Overexpression of miR-146a significantly facilitated viral infection, evidenced by the increased transcription of viral CP and RdRp genes, while miR-146a knockdown by specific inhibitors decreased RGNNV replication. Using pMIR-REPORT Luciferase system, we found that the 3' untranslated region (UTR) of grouper TRAF6 could be specifically targeted by miR-146a. Further studies showed that its downstream target gene pro-inflammatory cytokines, including TNF-alpha, IL-8 and IL-beta, were all significantly decreased in miR-146a mimic transfected cells, but increased in miR-146a inhibitors transfected cells during RGNNV infection. Thus, our results suggested and verified that holding the level of miR-146a exerted crucial roles in RGNNV infection through TRAF6-mediated inflammatory response