Showing papers in "Journal of Ocean University of China in 2011"

A FVCOM-based unstructured grid wave, current, sediment transport model, I. Model description and validation

Abstract: An effort was made to couple FVCOM (a three-dimensional (3D), unstructured grid, Finite Volume Coastal Ocean Model) and FVCOM-SWAVE (an unstructured grid, finite-volume surface wave model) for the study of nearshore ocean processes such as tides, circulation, storm surge, waves, sediment transport, and morphological evolution. The coupling between FVCOM and FVCOM-SWAVE was achieved through incorporating 3D radiation stress, wave-current-sediment-related bottom boundary layer, sea surface stress parameterizations, and morphology process. FVCOM also includes a 3D sediment transport module. With accurate fitting of irregular coastlines, the model provides a unique tool to study sediment dynamics in coastal ocean, estuaries, and wetlands where local geometries are characterized by inlets, islands, and intertidal marsh zones. The model was validated by two standard benchmark tests: 1) spectral waves approaching a mild sloping beach and 2) morphological changes of seabed in an idealized tidal inlet. In Test 1, model results were compared with both analytical solutions and laboratory experiments. A further comparison was also made with the structured grid Regional Ocean Model System (ROMS), which provides an insight into the performance of the two models with the same open boundary forcing.

Enzymatic hydrolysis of defatted mackerel protein with low bitter taste

Abstract: Ultrasound-assisted solvent extraction was confirmed as a novel, effective method for separating lipid from mackerel protein, resulting in a degreasing rate (DR) of 95% and a nitrogen recovery (NR) of 88.6%. To obtain protein hydrolysates with high nitrogen recovery and low bitter taste, enzymatic hydrolysis was performed using eight commercially available proteases. It turned out that the optimum enzyme was the ‘Mixed enzymes for animal proteolysis’. An enzyme dosage of 4%, a temperature of 50°, and a hydrolysis time of 300 min were found to be the optimum conditions to obtain high NR (84.28%) and degree of hydrolysis (DH, 16.18%) by orthogonal experiments. Glutamic acid was the most abundant amino acid of MDP (defatted mackerel protein) and MDPH (defatted mackerel protein hydrolysates). Compared with the FAO/WHO reference protein, the essential amino acid chemical scores (CS) were greater than 1.0 (1.0–1.7) in MDPH, which is reflective of high nutritional value. This, coupled with the light color and slight fishy odor, indicates that MDPH would potentially have a wide range of applications such as nutritional additives, functional ingredients, and so on.

Morphology and molecular identification of Ulva forming green tides in Qingdao, China

Abstract: Green tides are caused by the proliferation of chlorophytes under suitable hydrographic conditions. These blooms lead to environmental degradation and negatively impact the waters and seagrass beds, as well as fishing and other recreational activities in the bay. A comprehensive ecological understanding of the bloom dynamics, including the origin and persistence, is needed to foster management decisions. The algae in the great majority of green tide blooms usually belong to two genera of Ulvophyceae, Ulva and Enteromorpha. Ulva has been observed more often in recent years. In China, green tides occurred for the first time in the middle area of the Yellow Sea in 2007, and a large-scale algae blooming broke out in the middle and southern areas of the Yellow Sea in late May 2008. We identified them as Ulva prolifera by comparative analysis of the rDNA internal transcribed spacer 1 (ITS1), 5.8S and ITS2 sequences in combination with microscopic observation. Morphological differences were found between the free-floating algae and the attached thalli. Various reproduction patterns of the free-floating algae include sexual, asexual and vegetative propagations, which played important roles in the long-term green tide persistence in China. The ITS sequences of the blooming algae were identical to those of the samples from the Lianyungang sea area but were different from the attached samples from the Qingdao sea area. The results infer that the blooms are originated from other sea areas rather than from the local attached populations.

Identification and characterization of a new IgE-binding protein in mackerel (Scomber japonicus) by MALDI-TOF-MS

Abstract: As fish is one source of the ‘big eight’ food allergens, the prevalence of fish allergy has increased over the past few years. In order to better understand fish allergy, it is necessary to identify fish allergens. Based on the sera from fish-allergenic patients, a 28 kDa protein from local mackerel (Scomber japonicus), which has not been reported as a fish allergen, was found to be reactive with most of the patients’ sera. The 28 kDa protein was analyzed by MALDI-TOF-MS (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry). Mascot search in NCBI database (Date: 08/07/2010) showed that the top protein matched, i.e. triosephosphate isomerase (TPI) from Xiphophorus maculatus and Poecilia reticulata, had a mowse (molecular weight search) score of 98. In addition, TPI from Epinephelus coioides also matched this mackerel protein with a mowse score of 96. Because TPI is considered as an allergen in other non-fish organisms, such as lychee, wheat, latex, archaeopotamobius (Archaeopotamobius sibiriensis) and crangon (Crangon crangon), we consider that it may also be an allergen in mackerel.

Preparation of cationic chitosan-polyacrylamide flocculant and its properties in wastewater treatment

Abstract: Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC) as raw materials and ceric ammonium nitrate (CAN) as initiator. The flocculation ability of the resulting polymer (PCAD) was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of chitosan and DMC content on PCAD’s flocculation ability were studied. Flocculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the chitosan’s content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD’s flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15–20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD’s dosage was 8mg·L−1. Compared with cationic polymer (the copolymer of AM and DMC, PAD), PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.

Biosorption of Cd(II) and Pb(II) ions by aqueous solutions of novel alkalophillic Streptomyces VITSVK5 spp. biomass

Abstract: Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment. Biosorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution. The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species. The biosorption property of Streptomyces VITSVK5 spp. was investigated by absorbing heavy metals Cadmium (Cd) and Lead (Pb). Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L−1, cadmium 3.1±0.3μg L−1, zinc 8.4±2.6μg L−1 and copper 0.3±0.1μg L−1, whereas mercury was well below the detection limit. The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated. The optimum pH for maximal biosorption was 4.0 for Cd (II) and 5.0 for Pb (II) with 41% and 84% biosorption respectively. The biosorbent dosage was optimized as 3 g L-1 for both the trace metals. Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl (-COOH), hydroxyl (-CHOH) and amine (-NH2) groups of biomass with the metal ions. This could be mainly involved in the biosorption of Cd (II) and Pb (II) onto Streptomyces VITSVK5 spp. The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.

Effects of carboxymethyl-chitosan on wound healing in vivo and in vitro

Abstract: Effects of carboxymethyl-chitosan with different molecular weights on wound healing were investigated in vivo and in vitro. A second degree burn model was performed in rats and the accelerative effects of carboxymethyl-chitosan on wound repair were observed. Contents of transforming growth factor (TGF)-β1, interleukin(IL)-6 and matrix metalloproteinase (MMP)-1 in wounds were determined by enzyme-linked immunosorbent assay (ELISA). In vitro study evaluated the influence of carboxymethyl-chitosan on cytokines secretion of fibroblasts and macrophages. In vivo results showed that carboxymethyl-chitosan effectively accelerated the wound healing process in burned rats (P<0.05). Levels of TGF-β1, IL-6 and MMP-1 in carboxymethyl-chitosan groups were significantly elevated, compared with control group (P<0.05). In vitro results indicated that carboxymethyl-chitosan significantly promoted the proliferation of fibroblasts and stimulated its IL-8 and IL-10 secretion at different incubation time, but it did not affect collagen secretion of fibroblasts. Carboxymethyl-chitosan enhanced phagocytosis ability of macrophages, and increased its tumor necrosis factor (TNF)-α secretion. In conclusion, carboxymethyl-chitosan promoted wound healing by activating macrophages, accelerating fibroblasts growth and exerting considerable effects on the secretion of a series of cytokines.

Amino acid composition and functional properties of giant red sea cucumber (Parastichopus californicus) collagen hydrolysates

Abstract: Giant red sea cucumber (Parastichopus californicus) is an under-utilized species due to its high tendency to autolysis. The aim of this study was to evaluate the functional properties of collagen hydrolysates from this species. The degree of hydrolysis (DH), amino acid composition, SDS-PAGE, emulsion activity index (EAI), emulsion stability index (ESI), foam expansion (FE), and foam stability (FS) of hydrolysates were investigated. The effects of pH on the EAI, ESI FE and FS of hydrolysates were also investigated. The results indicated that the β and α1 chains of the collagen were effectively hydrolyzed by trypsin at 50°c with an Enzyme/Substrate (E/S) ration of 1:20 (w:w). The DH of collagen was up to 17.3% after 3 h hydrolysis with trypsin. The hydrolysates had a molecular weight distribution of 1.1–17 kDa, and were abundant in glycine (Gly), proline (Pro), glutamic acid (Glu), alanine (Ala) and hydroxyproline (Hyp) residues. The hydrolysates were fractionated into three fractions ( 10 kDa), and the fraction of 3–10 kDa exhibited a higher EAI value than the fraction of > 10 kDa (P 10 kDa had higher FE and FS values than other fractions (P 10 kDa showed higher FE value, respectively. They are hoped to be utilized as functional ingredients in food and nutraceutical industries.

Influence of temperature and salinity on germination of eelgrass ( Zostera marina L.) seeds

Abstract: Seagrass restoration as part of ocean ecosystem protection has been launched for many years all over the world, but intensive research on this subject in China has just begun in recent years Seed broadcasting has been widely accepted as the most potentially useful method for seagrass restoration over large areas We examined the influence of key environmental factors on seed germination to help promote eelgrass bed restoration Under anoxic conditions, the influence of temperature and salinity on the germination rate of eelgrass (Zostera marina L) seeds was examined at different combinations of four temperatures (4, 9, 14, and 24°C) and nine salinities (5 to 45, increment of 5) The effect of significant interaction of temperature and salinity on germination rate was observed (ANOVA) (P<0001) The highest germination rate (833 ± 35)% was reached in 8 weeks at 14°C and salinity 5 Higher temperature significantly increased the germination rate at salinity 5 (P<0001) during the whole observation period except for 24°C, while lower salinity significantly increased the germination rate at 14°C (P<0001) Although significant interaction was found between temperature and salinity (P<0001), the influence of salinity was stronger than that of temperature for the germination of eelgrass seeds These results provide useful information for the propagation of artificial seedlings for seagrass restoration in China

Establishment of a spleen cell line from large yellow croaker Pseudosciaena crocea and its primitive application in foreign gene transfection

Abstract: A large yellow croaker, Pseudosciaena crocea, spleen (LYCS) cell line was established and the feasibility of using it for foreign gene transfection was evaluaed in this study. Primary culture of LYCS cells was initiated from spleen tissue pieces, which were cultured at 25°C in Dulbecco’s modiced Eagle medium/F12 medium (DMEM/F12, 1:1) (pH7.2), supplemented with 20% fetal bovine serum, carboxymethyl chitosan, chondroitin sulfate, basic fibroblast growth factor (bFGF) and insulin-like growth factor-I (IGF-I). The cultured LYCS cells, in fibroblast shape, proliferated to 100% confluency 20 days later. Chromosome analyses indicated that the LYCS cells exhibited chromosomal aneuploidy with a modal chromosome number of 48 which displayed the normal diploid karyotype of P. crocea (6m+6sm+36t, NF=60). A LYCS cell line, with a population doubling time of 48.7 h at passage 60, has been established and subcultured to passage 70. Transgenic feasibility test demonstrated that positive green fluorescence protein (GFP) expression was observed in LYCS cells after pcDNA3.1-GFP plasmid transfection. In conclusion, a continuous foreign gene transfection feasible LYCS cell line has been established successfully. The cell line might serve as a valuable tool for studies of transgenic breeding and has potential applications for different kinds of cytotechnological studies.

Influence of dietary probiotic Bacillus TC22 and Prebiotic fructooligosaccharide on growth, immune responses and disease resistance against Vibrio splendidus infection in sea cucumber Apostichopus japonicus

Abstract: The effects of probiotic Bacillus TC22 (isolated from intestine of infected sea cucumber) and prebiotic fructooligosaccharide (FOS) on growth, immunity and disease resistance in sea cucumber Apostichopus japonicus were studied Six experimental diets were formulated with combinations of three levels of TC22 (0, 107 and 109 CFU g−1 diet) and two levels of FOS (0 and 05%) in a 3 × 2 factorial experiment At the end of the 8-week feeding trial, animals were challenged by injecting Vibrio splendidus The results revealed that the specific growth rates (SGR) of sea cucumbers were not affected by TC22 and FOS, or the interaction between TC22 and FOS (P > 005) However, there were significant interactions between TC22 and FOS for immune response and disease resistance in sea cucumbers (P 005) Therefore, further studies should examine the effects of combinations of other levels of FOS (> 05% or < 05%) and TC22 on the immunity and disease resistance of sea cucumbers

Structure analysis of the complete mitochondrial genome in cultivation variety ‘Rongfu’

Abstract: In this report, complete mitochondrial genome sequences of Laminaria cultivation variety ‘Rongfu’ were obtained The results showed the length of circular molecule of mtDNA was 37 638 bp (647% A+T), encoding three rRNAs (23S, 16S and 5S), 25 tRNAs, 35 known mitochondrial proteins and 3 ORFs Sequence alignment indicated its mtDNA genome was very similar to that of Laminaria japonica Phylogenetic trees inferred from concatenated 30 mitochondrial genes showed that ‘Rongfu’, Laminaria japonica, Laminaria longipedalis, Laminaria diabolica, Laminaria religiosa and Laminaria ochotensis clustered together In addition, compared with mitochondrial genome of L japonica, ‘Rongfu’ mtDNA lacked a non-coding region of 19 nucleotides, which was located between rRNA small subunit gene 3 (rps3) and rRNA small subunit gene 9 (rps9) Seven cultivation varieties of China were divided into two groups based on this non-coding region which was absent in ‘Rongfu’, ‘Fujian’ and ‘Sanhai’ while present in ‘Ailunwan’, ‘Dongfang No2’, ‘Dongfang No3’ and ‘Zaohoucheng’ So this variation can be used in germplasm identification of cultivation variety

Heavy metal distribution in sediments of Muthupettai mangroves, south east coast of India

Abstract: Core sediments from the Muthupettai mangroves on the southeast coast of India were analyzed for soil texture, total nitrogen, organic carbon, phosphorus and heavy metals (Fe, Mn, Cr, Cu, Ni, Pb, Zn and Cd). The distinct seasonal variation in the distribution of metals in the sediments was observed. The minimum concentration was recorded in river mouth and the maximum was in lagoon. High metal concentration in sediment was observed during monsoon and low concentration in summer. The total nutrient in lagoon and river mouth was recorded in the range of 4.528 to 8.526 mg g−1 for organic carbon, 2.213 to 10.5 mg g−1 for nitrogen and 0.824 to 7.22 mg g−1.

Effects of heavy metal ions (Cu 2+ , Pb 2+ and Cd 2+ ) on DNA damage of the gills, hemocytes and hepatopancreas of marine crab, Charybdis japonica

Abstract: There are rising concerns about the hazardous effects of heavy metals on the environment. In this study, comet assay and DNA alkaline unwinding assay were conducted on the tissues (gills, hepatopancreas, and hemocytes) of Charybdis japonica in order to illustrate genotoxicity of three heavy metal ions (Cu2+, Pb2+, and Cd2+) on the marine crabs C. japonica. The crabs were exposed to Cu2+ (10, 50, and 100 μg.L−1), Pb2+ (50, 250, and 500 μg L−1) and Cd2+ (5, 25, and 50 μg L−1), and the tissues were sampled at days 0.5, 1, 3, 6, 9, and 15. DNA alkaline unwinding assay was used for testing the DNA single strand break in gills and hepatopancreas and comet assay was employed for testing the DNA damage in hemocytes. The results showed that the DNA damage (F-value) of gills in the crabs exposed to the three heavy metals was decreased gradually during the exposure periods and there was a dose-time response relationship in certain time, suggesting that the levels of DNA single strand break in all the experimental groups increased significantly compared to the controls. Changes of F-value in hepatopancreas of the crabs exposed to the three heavy metals were similar to those in gills except that the peak values were found in the 500 μg L−1 Pb2+ treatment group at day 3 and the 50 μg L−1 Cd2+ treatment group at day 9. The ranks of DNA damage in gills and hepatopancreas induced by the three heavy metal ions (50 μg L−1, day 15) were Cd2+ >Pb2+ >Cu2+ and Pb2+ >Cu2+ >Cd2+. The levels of DNA damage in gills were higher than those in hepatopancreas in the same experimental group. It can be concluded that indices of DNA damage can be used as the potential biomarkers of heavy metal pollution in marine environment.

Analysis of the Global Swell Distributions Using ECMWF Re-Analyses Wind Wave Data

Abstract: The existence of three well-defined tongue-shaped zones of swell dominance, termed as ‘swell pools’, in the Pacific, the Atlantic and the Indian Oceans, was reported by Chen et al. (2002) using satellite data. In this paper, the ECMWF Re-analyses wind wave data, including wind speed, significant wave height, averaged wave period and direction, are applied to verify the existence of these swell pools. The swell indices calculated from wave height, wave age and correlation coefficient are used to identify swell events. The wave age swell index can be more appropriately related to physical processes compared to the other two swell indices. Based on the ECMWF data the swell pools in the Pacific and the Atlantic Oceans are confirmed, but the expected swell pool in the Indian Ocean is not pronounced. The seasonal variations of global and hemispherical swell indices are investigated, and the argument that swells in the pools seemed to originate mostly from the winter hemisphere is supported by the seasonal variation of the averaged wave direction. The northward bending of the swell pools in the Pacific and the Atlantic Oceans in summer is not revealed by the ECMWF data. The swell pool in the Indian Ocean and the summer northward bending of the swell pools in the Pacific and the Atlantic Oceans need to be further verified by other datasets.

A numerical study of the effects of coastal geometry in the Bohai Sea on storm surges induced by cold-air outbreaks

Abstract: Strom surges are not only determined by the atmospheric forcing, but also influenced by the coastal geometry and bathymetry. The Bohai Sea, as one of China’s marginal seas, is seriously harmed by storm surges, especially those caused by cold-air outbreaks. As the coastline of the Bohai Sea has changed evidently these years, storm surges may have new characteristics due to the changes in the local geometry. This paper aims to find out these new characteristics by primarily investigating the influence of the changes in the local geometry on storm surges with numerical methods. 20 scenarios were constructed based on the track and intensity of the cold-air outbreaks to describe the actual situation. By analyzing the model results of the control scenarios, it is found that the main changes of the maximum surge elevation occur in the Bohai Bay and the Laizhou Bay. At the top of the Bohai Bay, the maximum surge elevation is obviously decreased, while in the Laizhou Bay, it is enhanced by the growing Yellow River Delta. This, however, does not suggest that the storm surges in the Laizhou Bay become more serious. A comparison of the risk assessment of storm surges in the Tanggu, Huanghua and Yangjiaogou regions shows that the risk of storm surges in these coastal areas is lightened by the evolvement of the coastal geometry. Particularly near Yangjiaogou, though the maximum surge elevation becomes higher to subject more areas to risk, the risk is still reduced by the evolvement of the Yellow River Delta.

Dynamic Performance of a Semi-Submersible Platform Subject to Wind and Waves

Abstract: By applying experimental and numerical simulations, the motion performance of a semi-submersible platform with mooring positoning system under combined actions of wind and waves is studied. The numerical simulation is conducted by the method of nonlinear time domain coupled analysis, and the mooring forces are calculated by the piecewise extrapolating method. The scale in the model experiment is 1:100, and the mooring system of the model is designed with the method of equivalent water-depth truncation by comparing the numerical and the experimental results, the platform motion and mooring forces subject to wind and waves are investigated. The results indicate that the numerically simulated mooring forces agree well with the experimental results in static equivalent field, but show some difference in dynamic equivalent field; the numerically simulated platform motions coincide well with the experimental results. The maximum motion of the platform under operating conditions is 20.5 m. It means that the horizontal displacement is 2% less than the water depth, which satisfies the operating requirements.

Patterns and Cellular Mechanisms of Arm Regeneration in Adult Starfish Asterias rollestoni Bell

Abstract: To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were studied. It was found that cells in the outer epidermis and inner parietal peritoneum near the end of the stump began to dedifferentiate 4 d after amputation. The dedifferentiated cells in the outer epidermis proliferated, migrated to the wound site and formed a thickened pre-epidermis which would then re-differentiate gradually into mature epidermis. The new parietal peritoneum formed on the coelomic side of wound might be from the curvely elongated parietal peritoneum, resulting from the dedifferentiated and proliferated cells by extension. Afterwards, the proliferated cells made the outer epidermis and inner parietal peritoneum invaginate into the interior dermis and formed blastema-like structures together with induced dedifferentiated dermal cells. Most interestingly, the arm regeneration in A. rollestoni was achieved synchronously by de novo arm-bud formation and growth, and arm-stump elongation. The crucial aspects of arm-bud formation included cell dedifferentiation, proliferation and migration, while those of arm-stump elongation included cell dedifferentiation, proliferation, invagination, and arm-wall-across blastema-like structure formation. The unique pattern and cellular mechanisms of amputated arm regeneration make it easier to understand the rapid regeneration process of adult starfish. This study may lay solid foundations for the research into molecular mechanisms of echinoderm regeneration.

Effect of dopamine injection on the hemocyte count and prophenoloxidase system of the white shrimp Litopenaeus vannamei

Abstract: Effects of dopamine injection on the hemocyte count, phenoloxidase activity, serine proteinase activity, proteinase inhibitor activity and α2-macroglobulin-like activity in L. vannamei were studied. Results showed that dopamine injection resulted in a significant effect on the parameters measured (P < 0.05), while no significant difference was observed in the control group (0.85% NaCl). In the experimental groups, the hemocyte count reached the minimum in 3 h; granular and semi-granular cells became stable after 12 h and hyaline cells and the total hemocyte count became stable after 18 h. Phenoloxidase activity reached the minimum in 6 h, and then became stable after 9 h. Serine protease activity and proteinase inhibitor activity reached the minimum in 3 h, and α2-macroglobulin-like activity reached the maximum in 3 h, and all the three parameters became stable after 12 h. The results suggest that the activating mechanisms of the proPO system triggered by dopamine are different from those triggered by invasive agents or spontaneously activated under a normal physical condition.

Low-temperature affected LC-PUFA conversion and associated gene transcript level in Nannochloropsis oculata CS-179

Abstract: Nannochloropsis oculata CS-179, a marine eukaryotic unicellular microalga, is rich in long-chain polyunsaturated fatty acids (LC-PUFAs). Culture temperature affected cell growth and the composition of LC-PUFAs. At an initial cell density of 1.5 × 106 cell mL−1, the highest growth was observed at 25°C and the cell density reached 3 × 107 cell mL−1 at the beginning of logarithmic phase. The content of LC-PUFAs varied with culture temperature. The highest content of LC-PUFAs (43.96%) and EPA (36.6%) was gained at 20°C. Real-time PCR showed that the abundance of Δ6-desaturase gene transcripts was significantly different among 5 culture temperatures and the highest transcript level (15°C) of Nanoc-D6D took off at cycle 21.45. The gene transcript of C20-elongase gene was higher at lower temperatures (10, 15, and 20°C), and the highest transcript level (20°C) of Nanoc-E took off at cycle 21.18. The highest conversion rate (39.3%) of Δ6-desaturase was also gained at 20°C. But the conversion rate of Nanoc-E was not detected. The higher content of LC-PUFAs was a result of higher gene transcript level and higher enzyme activity. Compared with C20-elongase gene, Δ6-desaturase gene transcript and enzyme activity varied significantly with temperature. It will be useful to study the mechanism of how the content of LC-PUFAs is affected by temperature.

Inhibition of fish nodavirus by gymnemagenol extracted from Gymnema sylvestre

Abstract: Viral nervous necrosis (VNN) has emerged to become a major problem in the culture of larval and juvenile marine fish worldwide Bioactive phytochemicals isolated from commonly available medicinal plants are often screened for their efficacy in controlling fish viral diseases Occurrence of newer viral strains and resistance to existing antiviral drugs are problems currently associated with treatment of VNN, which necessitates looking for alternate sources for effective antiviral drugs The aim of the present study was to screen antiviral potential of gymnemagenol (C30H50O4) previously extracted from leaves of Gymnema sylvestre The fish nodavirus, grouper nervous necrosis virus (GNNV) in infected Sahul Indian Grouper Eye (SIGE) cell lines were used to study the antiviral activity of gymnemagenol under in vitro conditions The susceptibility of the virus to gymnemagenol was confirmed by measuring the viral titre (TCID50 mL−1) in virus-infected SIGE cells every 24 h Gymnemagenol at 20 μg mL−1 inhibited the proliferation of GNNV to 53% at the end of the 6th d by inhibiting the proliferation of GNNV-infected SIGE cells The viable SIGE cells were reduced to 47% as determined by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay The viral titre (TCID50 mL−1) was also reduced to log 28 at the end of the 7th d in gymnemagenol-treated SIGE cells after inoculated with GNNV when compared to untreated control SIGE cell viral titre (log 41) Based on our results it can be concluded that gymnemagenol could be used as an antiviral agent against GNNV infection

Characterization of EmpA protease in Vibrio anguillarum M3

Abstract: EmpA is an extracellular metalloprotease secreted by Vibrio anguillarum. For better understanding its role in the pathogenicity of V. anguillarum strain M3, empA insertion mutant was constructed. In the mutant it decreased in extracellular proteolytic activity, swarming motility, hemolytic activity and virulence on turbot (Scophthalmus maximus). Significant decline (by 5-fold) of extracellular proteolytic activity and similar growth curve between mutant and wild type strains indicated that EmpA was the major extracellular protease of M3. LD50 of mutant increased by 38-fold compared with wild type. No pro-EmpA was detected in the supernatant of culture, indicating that EmpA autolyzed to mature protein after 24 h. Secretion of EmpA in M3 was similar to that in NB10 strain. Attenuated virulence of mutant was similar to that of M93Sm strain. It was demonstrated that specific operation of EmpA was different from that in previous studies and EmpA contributed to the swarming motility and hemolytic activity in V. anguillarum strain M3. The results provides insight into understanding the function of EmpA and its potential application in vaccine development.

Cloning, expressing, and hemolysis of tdh, trh and tlh genes of Vibrio parahaemolyticus

Abstract: Vibrio parahaemolyticus (VP) is one of the pathogenic vibrios endangering net-cage cultured Pseudosciaena crocea, Fennerpenaeus chinensis, and shellfish in coastal areas of China. Several types of hemolysins produced by Vp have been characterized as major virulence factors. They are thermostable direct hemolysin (TDH), TDH-related hemolysin (TRH) and thermolabile hemolysin (TLH). In this study, we cloned tdh, trh, and tlh genes from the genome DNA of VP by polymerase chain reaction (PCR). We ligated the three genes into prokaryotic expression vector pET-28a (+), and transformed the recombinant plasmids into Escherichia coli BL21 (DE3). The expression of recombinant proteins was induced by isopropyl-β-D-thiogalacto-pyranoside (IPTG). The recombinant proteins were expressed in a form of inclusion bodies and thus purified with Ni-NTA affinity chromatography. Western blotting results showed that recombinant proteins, TDH, TRH and TLH, could be recognized by rabbit anti-VP serum. The three purified proteins were renatured by gradient dialysis. The renatured proteins exhibited hemolytic activity except for TLH in the presence of phosphatidylcholine. These results not only are helpful for better understanding these genes’ functions under a single factor level, but also provide evidence for VP vaccine engineering.

Coastal erosion along the west coast of the Taiwan Strait and it's influencing factors

Abstract: Based on the field surveys and repeated cross-profile observations combined with the comparison of many years’ topographic maps, this study shows the spatial variability and varying patterns of coastal erosion along the west coast of the Taiwan Strait Regional differentiation in the Meso-Cenozoic coastal tectonics determined the irregular coastline and geological background for large-scale coastal erosion distribution The intensity of coastal erosion on the west side of the Taiwan Strait is mild in the northern region, severe in the central region and modest in the southern region The beaches along the coast are mainly backed by dunes, seawalls or cliffs The dunes and beaches show periodic erosion and recovery along the coast adjacent to river mouths, while persistent retreat of frontal dunes and beaches tends to occur in other areas The beach erosion occurs mainly in front of seawalls Due to the low strength of the unconsolidated sediment the soft cliffs suffer the severest coastline recession Sea level rise and river sediment discharge reduction are main causes of coastal erosion Storm surge is common in the studied area and plays an important role in the progress of coastal erosion Human activities including coastal constructions and sand mining also tend to interfere strongly with the balance of sediment budget in some coastal cells

Field and laboratory observations on predation and prey selectivity of the scyphomedusa Chrysaora cf. caliparea in Southeast Indian waters

Abstract: Chrysaora cf. caliparea, one of the most abundant medusae species in India, seems to be an important predator in the coastal waters of Bay of Bengal. The ability of Chrysaora cf. caliparea to feed at maximum rate in high prey concentrations implies that this jellyfish can efficiently exploit dense prey patches, at least for a short period. This study presents preliminary information regarding digestion and feeding rate upon copepods in a warm water environment. The ingestion rate of the average-sized medusae Chrysaora cf. caliparea is well balanced in nature, which in turn implies that this jellyfish is tuned for optimal utilization of available prey resources. Comparison with earlier research indicates that prey escape speed is one important factor governing which prey will be captured. A full understanding of predation mechanics awaits further investigation of both predator and prey behavior. However, because of the scarcity of long-term quantitative population data most insights have to be made indirectly. Nevertheless, low abundance of Chrysaora cf. caliparea in the water column during summer (May 2007) and the overall annual abundance seem not to considerably affect the zooplankton population, especially copepods. The present work contributes to the knowledge of prey-predator relationship of the forgotten fauna in Indian waters, which is especially crucial for understanding the process of ecological recovery of coastal water environment.

Molecular identification of a species in genus Nannochloropsis

Abstract: Nannochloropsis is a genus of marine eukaryotic unicellular algae, which belongs to class Eustigmatophyceae. The species of Nannochloropsis which are fine rotifer feed and rich in eicosapentaenoic acid (EPA) are economically important. Species in this genus are usually 2–5μm in size and are morphologically similar, which makes their identification difficult. We obtained a monoclone of Nannochloropsis with plating method in this study. DNA was extracted and the quality was determined by restriction enzyme digestion and spectrophotometer analysis. The DNA extracted was used to amplify the sequences of 18S ribosomal RNA gene, ITS region of ribosomal RNA transcription unit and rbcL gene. The phylogenetic analysis was carried out by constructing the neighbor-joining trees with Tamura-Nei distances. The phylogenetic analysis showed that the monoclone is N. oceanica.

Hydrodynamic efficiency improvement of the High Skew Propeller for the underwater vehicle under surface and submerged conditions

Abstract: An algorithm based on the Boundary Element Method (BEM) is presented for designing the High Skew Propeller (HSP) used in an Underwater Vehicle (UV). Since UVs operate under two different kinds of working conditions (i.e. surface and submerged conditions), the design of such a propeller is an unwieldy task. This is mainly due to the fact that the resistance forces as well as the vessel efficiency under these conditions are significantly different. Therefore, some factors are necessary for the design of the optimum propeller to utilize the power under the mentioned conditions. The design objectives of the optimum propeller are to obtain the highest possible thrust and efficiency with the minimum torque. For the current UV, the main dimensions of the propeller are predicted based on the given required thrust and the defined operating conditions. These dimensions (number of blades, pitch, diameter, expanded area ratio, thickness and camber) are determined through iterative procedure. Because the propeller operates at the stern of the UV where the inflow velocity to the propeller is non-uniform, a 5-blade HSP is preferred for running the UV. Finally, the propeller is designed based on the numerical calculations to acquire the improved hydrodynamic efficiency.

Effects of organic enrichment on sandy beach meiofauna: A laboratory microcosm experiment

Abstract: Meiofauna samples from intertidal sediments of Qingdao No.2 Bathing Beach, China, were collected for field study, and subjected to organic enrichment in a laboratory microcosm experiment for 21 d. There were three different treatments including non-organic addition as the control, low-organic enrichment (2 g DW green algae per 150 mL) and high-organic enrichment (10 g DW green algae per 150 mL). After 21 d, the meiofauna richness decreased in both organic enrichment treatments. Among the three treatments, total meiofauna abundance was significantly different, and the control groups had higher abundance than the other two treatment groups. However, the responses of the meiofauna abundance in the two organic enrichment treatments were non-significantly different. The relationship of meiofaunal abundance and nematode/copepod ratios to organic matter and oxygen level in the microcosm experiments were discussed.

Expression patterns of cytochrome P450 aromatase genes during ovary development and their responses to temperature stress in female yellow catfish (Pelteobagrus fulvidraco)

Abstract: Cytochrome P450 aromatase (P450arom) plays a pivotal role in ovary development. In this study, we used semi-quantitative reverse transcription PCR (RT-PCR) to analyze spatiotemporal expressions of two P450arom genes (CYP19A and CYP19B) and their responses to temperature stress in female yellow catfish (Pelteobagrus fulvidraco). Tissue distribution pattern of CYP19 showed that CYP19B was abundantly expressed in fish brain and ovary (brain > ovary), but weakly in intestines, whereas CYP19A was exclusively expressed in ovary. Semi-quantitative RT-PCR analyses showed high transcript abundance of both CYP19A and CYP19B in the ovarian reproductive cycle, corresponding with serum estradiol-17β (E2) levels. Increases in aromatases, serum E2 and testosterone (T) levels in fish exposed to higher temperature indicated stimulation of ovarian maturation and recrudescence by heat stress in stages II and V during the ovarian cycle, whereas associated decreases in stage III suggested vitellogenesis inhibition by heat stress. Gene expression of CYP19 was closely related to levels of serum E2. Results demonstrated CYP19 played a crucial role in the reproductive cycle of female yellow catfish. Different temperature stress affected CYP19 gene expression in the fish ovarian reproductive cycle. Associated P450arom genes could be useful for studying physiological aspects of yellow catfish.

Application of ICP-AES with microwave digestion to detect trace elements in oysters from Jiaozhou Bay, China

Abstract: Using ICP-AES with microwave digestion, we determined the concentrations of 16 trace elements in oysters from six sampling points in Jiaozhou Bay. The distributions of the wholesome elements Zn, Fe and Mn, and heavy metals such as As, Cd, Hg and Pb were studied. The oysters collected are all rich in the wholesome trace elements, and the oysters from Licun River have the highest concentrations of the three wholesome trace elements. The concentrations of heavy metals in oysters from Licun River are the highest and those from Hongdao are the lowest. Compared with the domestic and foreign sea-areas, the heavy metal contents in the oysters from Jiaozhou Bay are less in amount than those from some developed countries, and more than those in Southeast China. This implies that the Jiaozhou Bay’s oysters have been polluted by the environment to some extent.