Institutional Repository of South China Sea Institute of Oceanology, CAS
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Establishment and characterization of a cell line from the head kidney of golden pompano Trachinotus ovatus and its application in toxicology and virus susceptibility
No full textA cell line derived from the head kidney of golden pompano Trachinotus ovatus (TOHK) was established and characterized in this study. The TOHK cells grew most rapidly at 28 degrees C and the optimum foetal bovine serum concentration in L-15 medium was 10%. The TOHK cells have a diploid chromosome number of 2N = 54. The transfection efficiency of TOHK cells was 7<bold></bold>5% at the 15th passage and 72% at the 40th passage. The transfection efficiency in TOHK cells was high, so these cells are suitable for foreign gene expression. The cytotoxic effects of heavy metals and extracellular products from Vibrio anguillarum and Vibrio alginolyticus were demonstrated in TOHK cells, so this TOHK cell line could also be applied in environmental monitoring of heavy metals and pathogenic bacteria. TOHK cell line showed high virus susceptibility, such as grouper nervous necrosis virus (GNNV) and Singapore grouper iridovirus (SGIV). Then, TOHK cell line could be used for the study of viral pathogenesis and the development of antiviral strategies
ICTV Virus Taxonomy Profile: Iridoviridae
No full textThe Iridoviridae is a family of large, icosahedral viruses with double-stranded DNA genomes ranging in size from 103 to 220 kbp. Members of the subfamily Alphairidovirinae infect ectothermic vertebrates (bony fish, amphibians and reptiles), whereas members of the subfamily Betairidovirinae mainly infect insects and crustaceans. Infections can be either covert or patent, and in vertebrates they can lead to high levels of mortality among commercially and ecologically important fish and amphibians. This is a summary of the current International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Iridoviridae, which is available at www.ictv.global/report/iridoviridae
Effects of chronic ammonia exposure on ammonia metabolism and excretion in marine medaka Oryzias melastigma
No full textAmmonia is highly toxic to aquatic organisms, but whether ammonia excretion or ammonia metabolism to less toxic compounds is the major strategy for detoxification in marine fish against chronic ammonia exposure is unclear to date. In this study, we investigated the metabolism and excretion of ammonia in marine medaka Oryzias melastigma during chronic ammonia exposure. The fish were exposed to 0, 0.1, 0.3, 0.6, and 1.1 mmol l(-1) NH4Cl spiked seawater for 8 weeks. Exposure of 0.3-1.1 mmol l(-1) NH4Cl had deleterious effects on the fish, including significant reductions in growth, feed intake, and total protein content. However, the fish could take strategies to detoxify ammonia. The tissue ammonia (T-Amm) in the 0.3-1.1 mmol l(-1) NH4Cl treatments was significantly higher than those in the 0 and 0.1 mmol l(-1) NH4Cl treatments after 2 weeks of exposure, but it recovered with prolonged exposure time, ultimately reaching the control level after 8 weeks. The amino acid catabolic rate decreased to reduce the gross ammonia production with the increasing ambient ammonia concentration. The concentrations of most metabolites remained constant in the 0-0.6 mmol l(-1) NH4Cl treatments, whereas 5 amino acids and 3 energy metabolism-related metabolites decreased in the 1.1 mmol l(-1) NH4Cl treatment. J(Amm) steadily increased in ambient ammonia from 0 to 0.6 mmol l(-1) and slightly decreased when the ambient ammonia concentration increased to 1.1 mmol l(-1). Overall, marine medaka cope with sublethal ammonia environment by regulating the tissue T-Amm via reducing the ammonia production and increasing ammonia excretion. (C) 2017 Elsevier Ltd. All rights reserved
Antifungal and Antiviral Cyclic Peptides from the Deep-Sea-Derived Fungus Simplicillium obclavatum EIODSF 020
No full textA new linear peptide simplicilliumtide I (1) and four new cyclic peptides simplicilliumtides JM (25) together with known analogues verlamelins A and B (6 and 7) were isolated from the deep-sea-derived fungal strain Simplicillium obclavatum EIODSF 020. Their structures were elucidated by spectroscopic analysis, and their absolute configurations were further confirmed by chemical structural modification, Marfeys and Moshers methods. Compounds 2, 6, and 7 showed significant antifungal activity toward Aspergillus versicolor and Curvularia australiensis and also had obvious antiviral activity toward HSV-1 with IC50 values of 14.0, 16.7, and 15.6 mu M, respectively. The structurebioactivity relationship of this type of cyclic peptide was also discussed. This is the first time to discuss the effects of the lactone linkage and the substituent group of the fatty acid chain fragment on the bioactivity of this type of cyclic peptides. This is also the first time to report the antiviral activity of these cyclic peptides
Cytotoxic rearranged angucycline glycosides from deep sea-derived Streptomyces lusitanus SCSIO LR32
No full textTwo new rearranged linear angucycline glycosides, designated grincamycins G and H (1 and 2), together with three known congers P-1894B (vineomycin A(1), 3), saquayamycin B (4) and vineomycin B-2 (5), were obtained from marine-derived actinomycete Streptomyces lusitanus SCSIO LR32. The structures of 1 and 2 were elucidated by MS, 1D and 2D NMR techniques. Compounds 2-5 showed significant inhibitory effect on Jurkat T-cell proliferation with IC50 values of 3.0, 0.011, 0.037 and 0.3 mu M, respectively
Trajectory patterns of the annual cycle of the heat centre of the Indo-Pacific warm pool
No full textThe modulated annual cycle (MAC) of the Indo-Pacific warm pool (IPWP) heat centre location is investigated using the empirical mode decomposition-ensemble empirical mode decomposition method. The MAC and its interannual variability mainly affect the zonal and vertical locations of the heat centre; in fall and winter of El Nino years, the heat centre moves eastward from its normal location, with very little change in its meridional position. Four patterns of the heat centre trajectory in the IPWP are identified using the self-organizing map algorithm. Patterns 1 and 3 are both similar to a saddle, but pattern 1 is more winding. The shapes of patterns 2 and 4 are similar, but tilt in different directions: pattern 2 tilts southwest whereas pattern 4 tilts west. Of all the four patterns, the persistence of pattern 2 is generally relatively high. The trajectory of the heat centre develops in the sequence of patterns: 1-2-4-3-1. Pattern 1 (pattern 4) is related to the cold (warm) phase of the El Nino-Southern Oscillation (ENSO), while pattern 2 (pattern 3) corresponds to the negative (positive) phase of Indian Ocean dipole (IOD). The sequence of patterns in the trajectory of the heat centre in the IPWP is related to the IOD-ENSO interactions on a biennial timescale
Atmospheric aerosol compositions over the South China Sea: temporal variability and source apportionment
No full textIn order to evaluate impacts of different source emission on marine atmospheric particles over the South China Sea (SCS), major inorganic ionic concentrations (Na+, Cl-, SO42-, Ca2+, Mg2+, K+, NH4+ and NO3-) were determined in total suspended particulates (TSPs) at Yongxing Island, from March 2014 to February 2015. The annual average concentration of TSPs was 89.6 +/- 68.0 mu g m(-3), with 114.7 +/- 82.1, 60.4 +/- 27.0 and 59.5 +/- 25.6 mu g m(-3) in cool, warm and transition seasons, respectively. Cl- had the highest concentration, with an annual average of 7.73 +/- 5.99 mu g m(-3), followed by SO42- (5.54 +/- 3.65 mu g m(-3)), Na+ (4.00 +/- 1.88 mu g m(-3) ),Ca+2 C (2.15 +/- 1.54 mu g m(-3) /, NO3- (1.95 +/- 1.34 mu g m(-3)), Mg+2 (0.44 +/- 0.33 mu g m(-3)), K+ (0.33 +/- 0.22 mu g m(-3)) and NH4+ (0.07 +/- 0.07 mu g m(-3)) Concentrations of TSPs and the major ions showed seasonal variations, which were higher in the cool season and lower in the warm and transition seasons. Factors of influence were wind speed, temperature, relatively humidity, rain and air mass source region. Back trajectories, concentration- weighted trajectories (CWTs), and positive matrix factorization (PMF) of chemical compositions were analyzed for source apportionment, source contribution and spatiotemporal variation of major ions. Back trajectories and CWTs showed that air masses at Yongxing Island were mainly from the northeast, southwest and southeast in the cool, warm and transition seasons, respectively. The PMF results showed that 77.4% of Na+ and 99.3% of Cl- were from sea salt; 60.5% of NH4+ was from oceanic emission. Anthropogenic sources were very important for atmospheric aerosols over the island. Secondary inorganic aerosol of SO2 and NOx from fossil fuel combustion (especially coal in Chinese coastal regions) was the dominant source of NO3- (69.5 %) and SO42- (57.5 %)
The origin, historical variations, and distribution of heavy metals in the Qiongzhou Strait and nearby marine areas
No full textWe analyzed heavy metal concentrations in a number of surface sediments and cores from the Qiongzhou Strait and surrounding marine areas. The areas of high concentrations are primarily outside the eastern mouth of the Qiongzhou Strait and on the west side of the Leizhou Peninsula, whereas the areas of low concentrations are located primarily in the eastern Qiongzhou Strait. The maximum Cd, Pb and Zn concentrations in the samples collected in our study do not exceed the official standards for marine sediments, whereas the concentrations of Cr and Cu slightly exceed the standards. Correlations exist between the concentrations of Cu, Pb, Zn, Cr and Cd, and the concentrations of these metals are positively correlated with the mean particle size (phi value), indicating that the finer sediments have adsorbed greater amounts of heavy metal elements than the coarser sediments. An evaluation of the potential environmental risks demonstrates that certain indices of heavy metal pollution and environmental risks are relatively low and may be assigned low risk levels, thereby indicating that, in terms of heavy metals, the marine sedimentary environment in this region is only mildly impacted. Our analysis of the contaminant origins shows that the heavy metals in this region primarily originate in the Pearl River Estuary and that a small amount of them is derived from local runoff. The elevated heavy metal concentrations from the upper sections of the cores started 130 years ago, which indicats that heavy metals in the surface sediments are primarily due to human activities associated with industrialization
Variability of the Pacific North Equatorial Current and its implications on Japanese eel (Anguilla japonica) larval migration
No full textThe zonal velocity produced by a Regional Ocean Modeling System (ROMS)-based Pacific Ocean circulation model was validated against in situ measurements along the 137 degrees E longitude. The Pacific model successfully reproduced the position and the shape of the North Equatorial Current (NEC) as well as the latitude of maximum surface velocity in the NEC region (8-17 degrees N). The flow field produced by the Pacific model was then used to conduct numerical Lagrangian experiments, in which passive particles were released along a transect (142.5 degrees E, 12.5-17 degrees N) that traverses the known Japanese eel spawning area, and the effects of NEC strength and bifurcation latitude on the particle advection in the northwest Pacific were studied. Our results suggest that, in the 20-yr period (1993-2012), the variability of the currents alone can cause interannual variability of one order of magnitude in the Kuroshio Entrance (KE), the percentage of particles entering the Kuroshio, the range of which varies from 43% in 1997 to 6% in 2012. The yearly-averaged KE is not sensitive to the NEC bifurcation latitude. Instead, it is controlled by the average zonal velocity of a fixed domain (125-143 degrees E, 13.5-17 degrees N) and related to a recently-developed climate index, the Philippines-Taiwan Oscillation (PTO). During the positive phase of the PTO, the zonal velocity in the domain, hence the yearly-averaged KE, increases, and the opposite is true in the negative phase of the PTO. Considering only the trajectories, diel vertical migrations (DVM) in the top 400 m do not significantly affect Japanese eel larval transport, as incorporating DVM schemes does not increase the KE
Selection of internal wave beam directions by a geometric constraint provided by topography
No full textDirect numerical simulations are performed to investigate the generation of internal waves in a linearly stratified fluid by oscillating barotropic flows over a model continental shelf-slope topography. The presence of a third wave-beam emitted from an abrupt shelf break and transverse to the topography, which has not been adequately interpreted, is now explained in terms of a geometric constraint provided by the topography. This explanation applies to wave beam selection at any abrupt topographic junction point, no matter whether it is convex or concave, or its nearby slope is subcritical or supercritical. One exception is that, at an abrupt concave point with a nearby supercritical slope, the blocking effect leads to the presence of "dead water" (i.e., no flow) and thus no wave beam is emitted. On a critical slope, two beams with opposite directions are emitted from an amphidromic point that has a distinct distance from the shelf break. In addition to the internal wave dispersion relation that restricts possible wave beam directions to form an X-pattern, the geometric constraint proposed in the present work serves as a second selection mechanism that further restricts wave beam directions. The reflective direction of a wave beam incident onto a slope can also be explained by this geometric constraint. The present work provides an updated explanation of internal wave beams emitted at abrupt topographic junction points and unifies the explanation of the wave beam direction for both wave generation and reflection processes. Published by AIP Publishing