Institutional Repository of South China Sea Institute of Oceanology, CAS
Not a member yet
6199 research outputs found
Sort by
Vital role for the J-domain protein Mdj1 in asexual development, multiple stress tolerance, and virulence of Beauveria bassiana
No full textMdj1 is a member of the Hsp40 family containing a DnaJ or J domain. Here, we have examined the functions of an Mdj1 orthologue (56.68 kDa) in Beauveria bassiana, a filamentous fungal insect pathogen widely applied in biological control of insect pests. Deletion of mdj1 in B. bassiana resulted in significant growth defects on a variety of complex and minimal media. The Delta mdj1 mutant exhibited not only a drastic reduction (92 %) in aerial conidiation during optimal cultivation but also a remarkable decrease (77 %) in submerged blastospore production. Compared to wild-type, the deletion mutant was significantly more sensitive to the stresses of cell wall perturbation, high osmolarity, oxidation, carbendazim fungicide, several metal ions, and acidic/alkaline pH during conidial germination and/or colony growth. In the mutant, conidial thermotolerance and UV-B resistance decreased by 61 and 25 %, respectively, and virulence to Galleria mellonella larvae was largely attenuated. Transcript levels of many phenotype-related genes were drastically suppressed in the absence of mdj1, accompanied with impaired cell walls and reduced intracellular anti-stress molecules, including superoxide dismutases, catalases, glycerol, trehalose, and mannitol. These data indicate that Mdj1 plays a vital role in normal fungal development and contributes significantly to the biological control potential of B. bassiana against insect pests
Quinone/hydroquinone meroterpenoids with antitubercular and cytotoxic activities produced by the sponge-derived fungus Gliomastix sp ZSDS1-F7
No full textFifteen compounds, including six quinone/hydroquinone meroter-penoids, purpurogemutantin (1), macrophorin A (2), 4'-oxomacrophorin (3), 7-deacetoxyyanuthone A (4), 2,3-hydro-deacetoxyyanuthone A (5), 22-deacetylyanuthone A (6), anicequol (7), three roquefortine derivatives, roquefortine C (8), (16S)-hydroxyroquefortine C (9), (16R)-hydroxyroquefortine C (10), dihydroresorcylide (11), nectriapyrone (12), together with three fatty acid derivatives, methyl linoleate (13), phospholipase A 2 (14), methyl elaidate (15), were isolated from the sponge-derived fungus Gliomastix sp. ZSDS1-F7 isolated from the sponge Phakellia fusca Thiele collected in the Yongxing island of Xisha. Their structures were elucidated mainly by extensive NMR spectroscopic and mass spectrometric analyses. Among these compounds, compounds 1-3 and 5-7 showed significant in vitro cytotoxicities against the K562, MCF-7, Hela, DU145, U937, H1975, SGC-7901, A549, MOLT-4 and HL60 cell lines, with IC50 values ranging from 0.19 to 35.4 mu M. And compounds 2-4 exhibited antitubercular activity with IC 50 values of 22.1, 2.44 and 17.5 mu M, respectively. Furthermore, compound 7 had anti-enterovirus 71 activity with MIC value of 17.8 mu M. To the best of our knowledge, this is the first report to product two quinone/hydroquinone meroterpenoids skeletons (linear skeleton and drimane skeleton) from the same fungal strain. [GRAPHICS]
TRAF6 is a critical factor in fish immune response to virus infection
No full textTumor necrosis factor receptor-associated factor 6 (TRAF6) is one of the key adaptor molecule in Toll-like receptor signal transduction that triggers downstream cascades involved in innate immunity. In our previous study, the molecular characteristics of EtTRAF6 (TRAF6 from Epinephelus tauvina), the tissue distributions, expression patterns after challenging with bacterial and viral pathogens were investigated. Here we identified EtTRAF6 as an important regulator of virus-triggered signaling pathway. Over expression of EtTRAF6-ORF and truncated forms of EtTRAF6, including EtTRAF6-C (delete the MATH domain), EtTRAF6-N (delete the RING domain) and EtTRAF6-MATH, inhibited IFN-beta activity strongly in grouper spleen (GS) cells. Overexpression of EtTRAF6 repressed virus-induced production of type I IFNs. When EtTRAF6 cotransfected with EcIRF3 or EcIRF7, EtTRAF6 inhibited IRF-induced activation of IFN-beta. Over-expressed EtTRAF6 inhibited" the transcription of SGIV genes significantly in GS cells. Although TRAF6 has a role in apoptosis regulation, it is not known if EtTRAF6 has any role in apoptosis regulation. Strikingly, when over-expressed in fathead minnow (FHM) cells, EtTRAF6 protected them from cell death induced by SGIV. Therefore, these results suggest that TRAF6 may play a critical role in their response to SGIV infection, through regulation of a cell death pathway that is common to fish and humans. (C) 2016 Elsevier Ltd. All rights reserved
Temperature shapes coral-algal symbiosis in the South China Sea
No full textWith the increase in sea surface temperature (SST), scleractinian corals are exposed to bleaching threats but may possess certain flexibilities in terms of their associations with symbiotic algae. Previous studies have shown a close symbiosis between coral the and Symbiodinium; however, the spatial variation of the symbiosis and the attribution underlying are not well understood. In the present study, we examined coral-algal symbiosis in Galaxea fascicularis and Montipora spp. from three biogeographic regions across similar to 10 degrees of latitude in the South China Sea. Analysis of similarities (ANOSIM) indicated a highly flexible coral-algal symbiosis in both G. fascicularis and Montipora spp. and canonical correspondence analysis (CCA) showed that temperature explained 83.2% and 60.1% of the explanatory subclade variations in G. fascicularis and Montipora spp., respectively, which suggested that temperature was the main environmental factor contributing to the diversity of Symbiodinium across the three regions. The geographic specificity of the Symbiodinium phylogeny was identified, revealing possible environmental selection across the three regions. These results suggest that scleractinian corals may have the ability to regulate Symbiodinium community structures under different temperatures and thus be able to adapt to gradual climate change
Spatial distributions of delta C-13, delta N-15 and C/N ratios in suspended particulate organic matter of a bay under serious anthropogenic influences: Daya Bay, China
No full textStable isotopic signatures (delta C-13 and delta N-15) and C/N ratios of suspended particulate organic matter (POM) were investigated from the surface water of Daya Bay during summer and winter of 2015. The relatively high 813Crom values suggested the input of C-13-depleted terrigenous organic matter was low in Daya Bay. There were significant correlations between delta C-13(POM) values and chlorophyll a concentrations both during summer and winter, suggesting the delta C-13(POM) values were mainly controlled by the phytoplankton biomass in the surface water. The distribution of delta N-15(POM) values was more complicated than that of delta C-13(POM) and displayed low values in the outer bay and the Dan'ao River estuary. N-15-depleted ammonia originating from industrial wastewater might have strongly influenced the water quality and stable isotopic signatures of POM near the Dan'ao River estuary. The delta C-13(POM) and delta N-15(POM) values strongly reflect the influences of anthropogenic activity and eutrophication in Daya Bay. (C) 2016 Elsevier Ltd. All rights reserved
Morphological and molecular evidence of hybridization events between two congeneric oysters, Crassostrea hongkongensis and C. ariakensis, in southern China
No full textCytochalasin P-1, a new cytochalasin from the marine-derived fungus Xylaria sp SOF11
No full textA new cytochalasin, named cytochalasin P-1 (1), together with four known analogs (2-5) was isolated from marine-derived fungus Xylaria sp. SOF11 from the South China Sea. The structure of the new compound was elucidated on the basis of MS and NMR (H-1, C-13, HSQC, HMBC, and NOESY) data analyses. Compounds 1-5 were tested for their cytotoxicities against four tumor cell lines (SF-268, MCF-7, NCI-H460, and HepG-2). Compounds 1-5 showed significant cytotoxicity against two tumor cell lines MCF-7 and SF-268, with the IC50 values varying between 0.33 and 4.17 mu M
A bacterial infection by Vibrio harveyi causing heavy reduction of cultured lined seahorse Hippocampus erectus
No full textComparative Characterization of Sequence Structure, Gene Expression, and Enzyme Activity of Alpha-2-macroglobulin between Stichopus monotuberculatus (Stichopodidae) and Holothuria atra (Holothuriidae)
No full textAlpha-2-macroglobulin (A(2)M) is essential for hosts defending against pathogen infections. In this study, two distinct A(2)Ms were identified from sea cucumbers Stichopus monotuberculatus and Holothuria atra, which belong to different genera in the Phylum Echinodermata, and named StmA(2)M and HaA(2)M, respectively. Structural analysis of StmA(2)M and HaA(2)M revealed that all contain the bait region domain, thioester domain, and receptor-binding domain. Phylogenetic analysis indicated that StmA(2)M and HaA(2)M all belong to the echinoderm A(2)Ms. The cleavage site RXXR and the catalytic histidine residue for complement component C3 were found in StmA(2)M and HaA(2)M. Compared with human A(2)M, the three-dimensional structures of StmA(2)M and HaA(2)M were more similar to that of common carp A(2)M. Both StmA(2)M and HaA(2)M showed the strongest response at transcriptional levels to lipopolysaccharide (LPS) at 12h and polyriboinosinic polyribocytidylic acid [Poly (I: C)] at 24h, respectively. Activity of StmA(2)M showed the strongest response to Poly (I: C) at 6h, while the strongest change of HaA(2)M activity was induced by LPS at 24h. The differential mRNA expression and enzyme activity levels suggested that A(2)M in sea cucumbers might be involved in different immune responses to LPS or Poly (I: C) challenge
Simultaneous photocatalytic Cr(VI) reduction and ciprofloxacin oxidation over TiO2/Fe-omicron composite under aerobic conditions: Performance, durability, pathway and mechanism
No full textCoexistence of organic compounds and heavy metals in aquaculture waters is a widespread problem. In this study, a rapid reduction of Cr(VI) and oxidation of ciprofloxacin (CIP) in a simultaneous manner was firstly reported through the photocatalysis of TiO2/Fe-omicron composite under aerobic conditions. The significantly enhanced removals of Cr(VI) and CIP by TiO2/Fe-omicron composite due to a synergetic effect between oxidation and reduction processes. Within 60 min UV light irradiation, the simultaneous removals of Cr(VI) and CIP by TiO2/Fe-omicron composite were 97.7 and 94.6%, respectively, whereas the corresponding values by TiO2 Were 57.9 and 68.7%. CIP oxidation process could be significantly accelerated under acidic and aerobic conditions. Intriguingly, a low Pb(II) concentration could induce an enhancement of CIP oxidation, whereas a negative effect on both Cr(VI) reduction and CIP oxidation was observed at a relatively high concentration. A low concentration of ethylene diamine tetra-acetic acid (EDTA) did positively affect both Cr(VI) reduction and CIP oxidation processes, whereas a negative effect on CIP oxidation was found at a relatively high concentration. A possible reaction pathway and mechanism between CIP oxidation and Cr(VI) reduction was proposed. CIP was attacked by HO- produced from the decomposition of water and photo-excited holes through substitution and hydroxylation processes, leading to the production of a series of intermediates, whereas the Cr(VI) was converted into Cr(III) through the capture of photo -excited electrons and Fe reduction. (C)2017 Elsevier B.V. All rights reserved