Institutional Repository of South China Sea Institute of Oceanology, CAS
Not a member yet
6199 research outputs found
Sort by
MKK7 confers different activities to viral infection of Singapore grouper iridovirus (SGIV) and nervous necrosis virus (NNV) in grouper
No full textMitogen-activated protein kinase 7 (MKK7) is one of the major stress-activated protein kinase (SAPK)activating kinases in response to environmental or physiological stimuli. Here a MKK7 named as Ec-MKK7 was identified from orange-spotted grouper, Epinephelus coioides. The full-length cDNA of Ec-MKK7 was 1853 bp, with an open reading frame (ORF) of 1272 bp encoding a putative protein of 423 amino acids. A characteristic S-K-A-K-T motif was contained in the domain of dual-specificity protein kinase, mitogen-activated protein kinase kinase 7 (PKc_MKK7). Intracellular localization showed that Ec-MKK7 was localized in both the cytoplasm and the nucleus of grouper spleen (GS) and/or grouper brain (EAGB) cells. Moreover, Ec-MKK7 was universally expressed in all examined tissues and showed expression modulation to challenges of lipopolysacchride (LPS), Singapore grouper iridovirus (SGIV) and polyriboinosinic polyribocytidylic acid (poly I:C) in vivo. A gene targeting strategy over-expressing Ec-MKK7 was performed to examine the activities of MKK7 to viral infection in vitro. Our data showed that Ec-MKK7 was involved in the evasion and replication of SGIV but played an antiviral role to the infection of nervous necrosis virus (NNV). All results demonstrated that Ec-MKK7 could play important roles in grouper innate immunity and show distinct functions on virus infection. (C) 2016 ElSevier Ltd. All rights reserved
Cloning, expression and characterization of a lipase gene from marine bacterium Pseudoalteromonas lipolytica SCSIO 04301
No full textA lipase gene, lip1233, isolated from Pseudoalteromonas lipolytica SCSIO 04301, was cloned and expressed in E. coli. The enzyme comprised 810 amino acid residues with a deduced molecular weight of 80 kDa. Lip1233 was grouped into the lipase family X because it contained a highly conserved motif GHSLG. The recombinant enzyme was purified with Ni-NTA affinity chromatography. The optimal temperature and pH value of Lip1233 were 45A degrees C and 8.0, respectively. It retained more than 70% of original activity after being incubated in pH ranging from 6.0 to 9.5 for 30 min. It was stable when the temperature was below 45A degrees C, but was unstable when the temperature was above 55A degrees C. Most metal ions tested had no significant effect on the activity of Lip1233. Lip1233 remained more than original activity in some organic solvents at the concentration of 30% (v/v). It retained more than 30% activity after incubated in pure organic solvents for 12 h, while in hexane the activity was nearly 100%. Additionally, Lip1233 exhibited typical halotolerant characteristic as it was active under 4M NaCl. Lip1233 powder could catalyze efficiently the synthesis of fructose esters in hexane at 40A degrees C. These characteristics demonstrated that Lip1233 is applicable to elaborate food processing and organic synthesis
Distortion and broadening of internal solitary wavefront in the northeastern South China Sea deep basin
No full textInternal solitary waves (ISWs) with peculiar fronts are frequently observed in the world ocean by satellite images, though with quite few explanations. In this study a distorted and broadening ISW front across the northeastern South China Sea deep basin is presented by using synthetic aperture radar (SAR) image. To illustrate this peculiar front, a nonlinear refraction model is developed to simulate and evaluate the effects of realistic bottom topography, current, and stratification on its transformation. Simulated results in realistic oceanic environments show good agreements with this SAR-observed front. Based on separate and comparative results in different background environments, we demonstrate that the distortion is actually caused by the strong mesoscale currents at periphery of an anticyclonic eddy. Moreover, the broadening is due to the difference in change of wave half width at different rays, which is associated with the different transformation of ISWs across variable bottom topography in the deep basin
Features and variability of the South China Sea western boundary current from 1992 to 2011
No full textDifferent from the traditional definition of the South China Sea western boundary current (SCSWBC), in this paper, only the southwestward and southward currents along the northern and western slopes in the SCS, which are closely associated with the basin-wide wind stress curl, are defined as the SCSWBC, while the flows on the southwestern shelf driven directly by the local wind stress are regarded as part of the shelf circulation. Using a new reanalysis dataset of the SCS in conjunction with the in situ and remote sensing data, the main features and variability of the SCSWBC from 1992 to 2011 were studied. Dictated by the prevailing monsoonal winds and in- and outflows, the SCSWBC in winter extended the full length of the western slope and reached its maximum intensity off the southeast coast of Vietnam, while in summer the main body of the SCSWBC was limited to the northern half of the western slope and merged with the northward coastal current to form the Vietnam Offshore Current (VOC) at about 12A degrees N. Moreover, the respective seasonal patterns of the SCSWBC showed pronounced interannual variations in its structure, including the axis, the width, and the maximum depth. The strength of the SCSWBC, with the transport of -11.8 A +/- 3.5 Sv in winter and -3.0 A +/- 1.6 Sv in summer off the central coast of Vietnam, also varied significantly from year to year. It was demonstrated that the monsoonal forcing over the SCS, the interannual variability of which was closely associated with El Nio events, played an important role in modulating the interannual variability of the SCSWBC, whereas the influence from the upper-layer Luzon Strait transport was secondary
Asperpyrone-Type Bis-Naphtho--Pyrones with COX-2-Inhibitory Activities from Marine-Derived Fungus Aspergillus niger
No full textBis-naphtho--pyrones (BNPs) are an important group of aromatic polyketides derived from fungi, and asperpyrone-type BNPs are produced primarily by Aspergillus species. The fungal strain Aspergillus niger SCSIO Jcsw6F30, isolated from a marine alga, Sargassum sp., and identified according to its morphological traits and the internal transcribed spacer (ITS) region sequence, was studied for BNPs secondary metabolisms. After HPLC/MS analysis of crude extract of the fermentation broth, 11 asperpyrone-type BNPs were obtained directly and quickly by chromatographic separation in the extract, and those isolated asperpyrone-type BNPs were structurally identified by NMR and MS analyses. All of the BNPs showed weak cytotoxicities against 10 human tumor cells (IC50 > 30 M). However, three of them, aurasperone F (3), aurasperone C (6) and asperpyrone A (8), exhibited obvious COX-2-inhibitory activities, with the IC50 values being 11.1, 4.2, and 6.4 M, respectively. This is the first time the COX-2-inhibitory activities of BNPs have been reported
Seasonal occurrence of Calanus sinicus in the northern South China Sea: A case study in Daya Bay
No full textCalanus sinicus is a calanoid copepod species that is distributed broadly in the continental shelf waters of the Northwest Pacific Ocean. This study aims to understand the seasonal variations of the distribution and abundance of C. sinicus in Daya Bay from the northern South China Sea (nSCS) and to explore its possible seasonal occurrence based on current and historical data. Monthly surveys of the species were conducted in Daya Bay, a subtropical bay in the nSCS, during the period between May 2013 and April 2014. C. sinicus was present from January to May, and disappeared after June. The spatial pattern of C sinicus in the bay was characterized by its distribution into the southwestern part of the bay in January, bay-wide spread in February, patchiness in March and virtual retreat from the bay mouth in April. Reproduction occurred from January to April at a low rate. Adults were mostly abundant in January and declined to a minimum in April. The percentage of early developmental stages increased from 54.1% in January to 90.1% in April, as collected by a fine mesh size. Based on historical data from Daya Bay and from the coastal waters of the nSCS, C. sinicus, was carried into the nSCS from the East China Sea by the China Coastal Current during the northeastern monsoon period and survived from December to October of the next year. The summer coastal upwelling may provide suitable refuges for the species in the nSCS by limiting the adverse effects caused by high temperatures. Our results confirm the viewpoint that C. sinicus could exist in the nSCS in summer and fall. (C) 2016 Elsevier B.V. All rights reserved
Early embryo and larval development of inviable intergeneric hybrids derived from Crassostrea angulata and Saccostrea cucullata
No full textTo detect the intergeneric hybridization between the oyster Crassostrea angulata and Saccostrea cucullata coexisting along the southern coast of China, reciprocal crosses were conducted between the two species. Barriers for sperm recognizing, binding, penetrating the egg, and forming the pronucleus were detected by fluorescence staining. From the results, although fertilization success was observed in hybrid crosses, the overall fertilization rate was lower than that of intraspecific crosses. A large number of hybrid larvae died at 6-8 d after hatching, and those survived could not complete metamorphosis. C. angulata a (TM) Eurox S. cucullata a (TM), larvae had a growth rate similar to that of the maternal species, whereas S. cucullata a (TM) Euro x C. angulata a (TM), larvae grew the slowest among all crosses. Molecular genetics analysis revealed that hybrid progeny were amphimixis hybrids. This study demonstrated that hybrid embryos generated by crossing C. angulata and S. cucullata could develop normally to the larval state, but could not complete metamorphosis and then develop to the spat stage. Thus, there is a post-reproductive isolation between C. angulata and S. cucullata
MHC polymorphism and disease resistance to Singapore grouper iridovirus (SGIV) in the orange-spotted grouper, Epinephelus coioides
No full textMajor histocompatibility complex (MHC) genes are critical members in both innate and adaptive immunity, and the association between their polymorphism and disease resistance has been reported in many teleosts. In the present study, we first investigated the genetic variation at the MHC II beta gene in orange-spotted grouper (Epinephelus coioides) after a challenge with Singapore grouper iridovirus (SGIV). The results reveal that a high polymorphism level of the MHC II beta gene (H = 1.000; K = 20.206; pi = 0.081) and at least three loci exist in grouper. The rate of dN/dS in the peptide-binding region (PBR) and non-PBR were both >1, suggesting the loci were evolving under positive selection. A high ratio of heterozygous individuals (37.26 %) and high rate of dN/dS were discovered, suggesting that both heterozygote advantage and frequency-dependent selection might result in the high polymorphism levels in MHC II beta genes in grouper. A total of 33 MHC II beta alleles were identified from 40 high-susceptibility (HS) and 40 high-resistance group (HR) individuals, and 15 alleles were used in the association analysis. Three alleles, EPCO-DBB*0302, EPCO-DBB*0307, EPCO-DBB*0603, and EPCO-DBB*1001 were significantly associated with resistance ability to SGIV, and the EPCO-DBB*0607 and EPCO-DBB*1303 alleles were associated with susceptibility (P < 0.05). To further confirm the association, another independent challenge experiment was performed. The result of association analysis in the verification test found that only EPCO-DBB* 1001 alleles were significantly associated with resistance to SGIV (P < 0.05), while the other alleles showed no significance (P > 0.05) in the frequency distribution between HR and HS groups. Therefore, the EPCO-DBB*1001 alleles could be used as a disease resistance-related MHC marker in the molecular marker-assisted selective breeding program of grouper
Characteristics of secondary Pg phases from OBS wide-angle seismic survey and their role in crustal imaging
No full textHow to eliminate or utilize secondary waves is one of the significant topics in processing of seismic data of seismic exploration. Little work is concerned with this aspect of wide-angle seismic survey using the ocean bottom seismometer (OBS), especially taking advantage of the secondary waves to improve seismic imaging. This study attempts to deepen understanding of the characteristics of the secondary Pg phase and to discuss its application to seismic imaging in OBS wide-angle seismic survey. We firstly identify the secondary Pg phase from synthetic seismogram sections and record waveforms, then calculate and analyze particle motions of primary Pg and secondary Pg phases through the azimuth angle rotation. With this knowledge, we determine the propagation path by the theoretical model simulation and calculation of measured data from the P wave travel forward modeling method based on the RAYINVR. Furthermore, we use the theoretical model and the actual model of OBS2010 to show the role of the crustal structure imaging. The secondary Pg phase is roughly parallel to and follows closely the primary Pg phase, and is continuous and clear with strong amplitude. An obvious vibration is observed behind the vibration of the primary Pg with stronger amplitude, which is supposed to be generated by the secondary Pg phase. On the basis of particle motions, the secondary Pg phase belongs to the P wave seismic phase. The travel-time fits of the possible propagation path based on the test data give three different results: (1) The chi(2) value is 14.921 when the reflective layer is water and sediment. (2) The chi(2) value is 193.264 when the reflective layer is only water. And (3) the chi(2) value is 1.786 when the reflective layer is merely sediment. Theoretical investigation and data tests lead to following conclusions: (1) The secondary Pg phase is actually a P-wave. (2) The secondary Pg phase is mainly from the reflection between the sediments. (3) This wave greatly increases the constraint to the basement. And (4) it can be used to improve the imaging resolution of the sediments and the upper crust
Cryptic prophages as targets for drug development
No full textBacterial chromosomes may contain up to 20% phage DNA that encodes diverse proteins ranging from those for photosynthesis to those for autoimmunity; hence, phages contribute greatly to the metabolic potential of pathogens. Active prophages carrying genes encoding virulence factors and antibiotic resistance can be excised from the host chromosome to form active phages and are transmissible among different bacterial hosts upon SOS responses. Cryptic prophages are artifacts of mutagenesis in which lysogenic phage are captured in the bacterial chromosome: they may excise but they do not form active phage particles or lyse their captors. Hence, cryptic prophages are relatively permanent reservoirs of genes, many of which benefit pathogens, in ways we are just beginning to discern. Here we explore the role of active prophage- and cryptic prophage-derived proteins in terms of (i) virulence, (ii) antibiotic resistance, and (iii) antibiotic tolerance; antibiotic tolerance occurs as a result of the non-heritable phenotype of dormancy which is a result of activation of toxins of toxin/antitoxin loci that are frequently encoded in cryptic prophages. Therefore, cryptic prophages are promising targets for drug development. (C) 2016 The Authors. Published by Elsevier Ltd