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Qiu Z.,Nanjing University of Information Science and Technology | Qiu Z.,Jiangsu Research Center for Ocean Survey Technology | Zheng L.,Nanjing University of Information Science and Technology | Zhou Y.,Zhejiang Fisheries Technical Extension Center | And 5 more authors.
Optics Express | Year: 2015

An innovative algorithm is developed and validated to estimate the turbidity in Zhejiang coastal area (highly turbid waters) using data from the Geostationary Ocean Color Imager (GOCI). First, satellite-ground synchronous data (n = 850) was collected from 2014 to 2015 using 11 buoys equipped with a Yellow Spring Instrument (YSI) multi-parameter sonde capable of taking hourly turbidity measurements. The GOCI data derived Rayleigh-corrected reflectance (Rrc) was used in place of the widely used remote sensing reflectance (Rrs) to model turbidity. Various band characteristics, including single band, band ratio, band subtraction, and selected band combinations, were analyzed to identify correlations with turbidity. The results indicated that band 6 had the closest relationship to turbidity; however, the combined bands 3 and 6 model simulated turbidity most accurately (R2 = 0.821, p<0.0001), while the model based on band 6 alone performed almost as well (R2 = 0.749, p<0.0001). An independent validation data set was used to evaluate the performances of both models, and the mean relative error values of 42.5% and 51.2% were obtained for the combined model and the band 6 model, respectively. The accurate performances of the proposed models indicated that the use of Rrc to model turbidity in highly turbid coastal waters is feasible. As an example, the developed model was applied to 8 hourly GOCI images on 30 December 2014. Three cross sections were selected to identify the spatiotemporal variation of turbidity in the study area. Turbidity generally decreased from near-shore to offshore and from morning to afternoon. Overall, the findings of this study provide a simple and practical method, based on GOCI data, to estimate turbidity in highly turbid coastal waters at high temporal resolutions. ©2015 Optical Society of America.


Chen J.,Zhejiang Fisheries Technical Extension Center | Chen J.,Zhejiang University | Chen J.,Zhejiang Aquatic Disease Prevention and Quarantine Center | Fang C.,Zhejiang University | And 7 more authors.
Foodborne Pathogens and Disease | Year: 2012

The ability to survive and proliferate in acidic environments is a prerequisite for the infection of Listeria monocytogenes. The glutamate decarboxylase (GAD) system is responsible for acid resistance, and three GAD homologs have been identified in L. monocytogenes: gadD1, gadD2, and gadD3. To examine whether GAD genes are specific to lineage, serovar, or certain subpopulation, we performed a systematic investigation on the prevalence of GAD genes in 164 L. monocytogenes. In contrast to gadD2 and gadD3 conserved in all L. monocytogenes strains, gadD1 was identified in 36.6% (60/164) of L. monocytogenes strains, including all serovar 1/2c and 68.5% (37/54) of serovar 1/2a strains, as well as a small fraction of serovar 1/2b (3.4%, 1/29) and lineage III (13.8%, 4/29) strains. All serovar 4b and lineage IV strains lacked this gene. According to the ascB-dapE structure, L. monocytogenes strains were classified into four subpopulations, carrying inlC2DE, inlGC2DE, inlGHE, or no internalin cluster, respectively. All L. monocytogenes strains with inlGC2DE or inlGHE pattern harbored gadD1, whereas those bearing inlC2DE or no internalin cluster between ascB and dapE lacked gadD1. In addition, other five non-monocytogenes Listeria species lacking ascB-dapE internalin cluster were gadD1-negative. Overall, the presence of gadD1 is not fully dependent on lineages or serovars but correlates with ascB-dapE internalin profiles, suggesting gadD1 might have co-evolved with the ascB-dapE internalin cluster in the primitive L. monocytogenes before divergence of serovars. © 2012, Mary Ann Liebert, Inc.


Yang D.,Zhejiang Ocean University | Yu W.,Wenling Environment Monitoring Station of Marine and Fishery | Miao Z.,Zhejiang Ocean University | Li M.,Wenling Environment Monitoring Station of Marine and Fishery | Zhou Y.,Zhejiang Fisheries Technical Extension Center
Proceedings - 2014 IEEE Workshop on Electronics, Computer and Applications, IWECA 2014 | Year: 2014

Based on hourly observational data on Temperature (T), salinity (S), dissolved oxygen (DO) and apparent oxygen utilization (AOU) in offshore cage aquaculture area in Yueqing Bay, eastern China, this paper tried to analysis the changing characteristics of these water quality parameters by means of maximum entropy method (MEM) and cross-correlation analysis (CCA). Results showed that, there were significant intra-day vairations for the water quality papameters under the influence of the flow tide. The intra-day changing periods of T, DO and AOU were 6.0 h and 12.0 h, while for S was 12.0 h. Under the influence of the flow tide, the changes of T was 6.0 h in advance of DO.Waters in autumn and winter was oxygen-enrich, and was suitable for aquaculture. © 2014 IEEE.


Chen J.,Zhejiang Fisheries Technical Extension Center | Chen F.,Technical Extension Center | Cheng C.,Zhejiang University | Fang W.,Zhejiang University
New Microbiologica | Year: 2013

Arginine deiminase and agmatine deiminase systems are involved in acid tolerance, and their encoding genes form the cluster lmo0036-0043 in Listeria monocytogenes. While lmo0042 and lmo0043 were conserved in all L. monocytogenes strains, the lmo0036-0041 region of this cluster was identified in all lineages I and II, and the majority of lineage IV (83.3%) strains, but absent in all lineage III and a small fraction of lineage IV (16.7%) strains, suggesting that the presence of the complete lmo0036-0043 cluster is dependent on lineages. lmo0036-0043-complete and -deficient lineage IV strains exhibit specific ascB-dapE profiles, which might represent two subpopulations with distinct genetic characteristics.


Chen J.,Zhejiang Fisheries Technical Extension Center | Zhu N.,Zhejiang Fisheries Technical Extension Center | Kong L.,Zhejiang Fisheries Technical Extension Center | Bei Y.,Zhejiang Fisheries Technical Extension Center | And 3 more authors.
Aquaculture | Year: 2013

Outbreaks of an epizootic in Chinese soft-shelled turtle (Trionyx sinensis) in Zhejiang province, China in 2012, caused severe economic losses to turtle culture industry. This disease was characterized by "soft dorsal shell" and "rugose abdominal shell" accompanied by significantly slower growth rate. Six bacterial isolates were collected from livers and kidneys of diseased turtles, and identified as Aeromonas sobria. Aeromonas veronii complex based on morphological and biochemical characteristics and phylogenetic analysis derived from 16S rRNA and six housekeeping genes. These isolates demonstrated pathogenic potential to juvenile Chinese soft-shelled turtles. To our knowledge, this is the first report of large-scale soft shell disease in Chinese soft-shelled turtles. © 2013 Elsevier B.V.


Chen J.,Zhejiang Fisheries Technical Extension Center | Jiang L.,Zhoushan Entry Exit Inspection and Quarantine Bureau | Lv Y.,National Fisheries Technical Extension Center | Liang Q.,Ningbo Entry Exit Inspection and Quarantine Bureau | And 3 more authors.
Journal of Chinese Institute of Food Science and Technology | Year: 2013

Listeria monocytogenes is an important foodborne pathogen of both humans and animals including aquatic animals. Serovar 4b causes the vast majority of listeriosis cases with a higher mortality rate than other serovars. In this study, we examined the molecular epidemiology and pathogenic potential of L. monocytogenes isolates from Chinese and imported aquatic products in an attempt to gain further insights on the public health risk caused by this organism. From the 3170 Chinese aquatic samples, the recovery rate of Listeria was 2.7%, with L. monocytogenes accounting for 22.2% of all samples. Serovar 1/2a predominated (42.1%), followed by serovars 1/2b (32.6%), 4b (15.8%) and 1/2c (10.5%). From the 1275 batches of aquatic products imported from 28 countries, the recovery rate of Listeria was 2.8%, similar to that in Chinese aquatic products (2.7%). However, L. monocytogenes accounted for a surprisingly high proportion (91.7%) compared to that in Chinese aquatic products (22.2%). Serovar 4b dominated (65.2%), with epidemic clones I (ECI) and II (ECU) recognized, followed by serovars 1/2b (17.4%), 1/2a (13.0%) and 1/2c (4.4%). Notably, the L. monocytogenes contamination in aquatic products from Chile (31.3%, mainly squid), Argentina (11.5%, mainly squid) and USA (11.1%, mainly salmon and sardine) was significantly higher than that from other countries (p<0.05). All of these isolates harbored a complete set of major infection-related genes, and were all as virulent as L. monocytogenes reference pathogenic strains revealed by cell plaque-forming and mouse assays. In conclusion, L. monocytogenes isolates from imported aquatic products pose higher risks than those from Chinese food system, suggesting inspection and quarantine strategies of aquatic products should be strengthened effectively.


Chen J.,Zhejiang Fisheries Technical Extension Center | Zhu N.,Zhejiang Fisheries Technical Extension Center | Kong L.,Zhejiang Fisheries Technical Extension Center | Bei Y.,Zhejiang Fisheries Technical Extension Center | And 3 more authors.
Aquaculture | Year: 2014

Recurrent outbreaks of an epizootic in Chinese soft-shelled turtles (Trionyx sinensis) in Zhejiang province, China in 2013, caused severe economic losses to turtle culture industry. This disease was characterized by listless swimming, craned or twisted neck, hyperemic laryngeal mucosa, and intumescent and hyperemic intestinal canal accompanied by mass mortality. Eleven diseased turtles with typical signs were collected from three distinct representative farms. Eleven bacterial isolates were collected from the livers and kidneys of diseased turtles and identified as Bacillus thuringiensis based on Vitek biochemical test, observation of rhizoid growth and protein toxin crystal production, 16S rRNA gene sequence analysis and Bacillus group species-specific PCR. These isolates demonstrated highly pathogenic potential to juvenile Chinese soft-shelled turtles with natural-infection-like symptoms. To our knowledge, this is the first case of B. thuringiensis infection in Chinese soft-shelled turtles and even in aquatic animals. © 2014 Elsevier B.V.


PubMed | Zhejiang Fisheries Technical Extension Center
Type: Journal Article | Journal: Foodborne pathogens and disease | Year: 2012

The ability to survive and proliferate in acidic environments is a prerequisite for the infection of Listeria monocytogenes. The glutamate decarboxylase (GAD) system is responsible for acid resistance, and three GAD homologs have been identified in L. monocytogenes: gadD1, gadD2, and gadD3. To examine whether GAD genes are specific to lineage, serovar, or certain subpopulation, we performed a systematic investigation on the prevalence of GAD genes in 164 L. monocytogenes. In contrast to gadD2 and gadD3 conserved in all L. monocytogenes strains, gadD1 was identified in 36.6% (60/164) of L. monocytogenes strains, including all serovar 1/2c and 68.5% (37/54) of serovar 1/2a strains, as well as a small fraction of serovar 1/2b (3.4%, 1/29) and lineage III (13.8%, 4/29) strains. All serovar 4b and lineage IV strains lacked this gene. According to the ascB-dapE structure, L. monocytogenes strains were classified into four subpopulations, carrying inlC2DE, inlGC2DE, inlGHE, or no internalin cluster, respectively. All L. monocytogenes strains with inlGC2DE or inlGHE pattern harbored gadD1, whereas those bearing inlC2DE or no internalin cluster between ascB and dapE lacked gadD1. In addition, other five non-monocytogenes Listeria species lacking ascB-dapE internalin cluster were gadD1-negative. Overall, the presence of gadD1 is not fully dependent on lineages or serovars but correlates with ascB-dapE internalin profiles, suggesting gadD1 might have co-evolved with the ascB-dapE internalin cluster in the primitive L. monocytogenes before divergence of serovars.


PubMed | Zhejiang University of Science and Technology, Zhejiang Fisheries Technical Extension Center and Zhejiang University
Type: | Journal: Gene | Year: 2016

The Chinese soft-shelled turtle (Pelodiscus sinensis) is a highly important freshwater aquaculture species in China. The molecular mechanisms underlying changes in immunity and growth in hybrid vigor are not well understood. In the present study, the transcriptomes from significantly different P. sinensis strains (Qingxi black turtle, B and Japanese strain, J) and the resulting hybrid (Zajiao-1, F) were sequenced using an Illumina sequencing platform. Differentially expressed genes (DEGs) between Zajiao-1 and the Qingxi black turtle were enriched mainly in the HTLV-I infection and Hippo signaling pathways, while DEGs between the Zajiao-1 and Japanese strain were enriched mainly in tryptophan metabolism, caner-associated pathways, transcriptional dysregulation in cancer, amebiasis, Fc-mediated phagocytosis and the peroxisome pathway. Highly expressed genes involved in the regulation of disorders of the fatty acid biosynthesis, immune and cardiovascular systems in P. sinensis were found among the DEGs. Enrichment categories for gene ontology included cellular processes, metabolic pathways, and the actin cytoskeleton pathway. The reliability of the sequencing data was verified through quantitative real-time polymerase chain reaction analysis of 20 immunity or growth-related genes. These findings offer new insights into heterosis of growth traits and resistance to stresses and potential strategies for selective breeding.


PubMed | Zhejiang Fisheries Technical Extension Center and Zhejiang University
Type: Journal Article | Journal: Genetics and molecular research : GMR | Year: 2015

The Chinese soft-shelled turtle (Pelodiscus sinensis) has been one of the most economically important aquatic animals in China for thousands of years, and several breeding strains have been formed. Since the morphological characteristics of some strains are similar, a rapid and accurate molecular method to differentiate between strains is required. In this study, partial sequences of mitochondrial DNA from four turtle strains, Taihu Lake Strain, Taiwan Strain, Japanese Strain, and Yellow River Strain, were amplified and sequenced based on selected strain-specific single nucleotide polymorphism (SNP) sites. The corresponding primers were designed and a high-resolution melting (HRM) technique was employed for genotyping these SNPs. The results indicated that a total of seven SNPs can be detected by HRM. Among these SNPs, one can be used for identifying the Taihu Lake Strain, one for the Japanese Strain, two for the Taiwan Strain, and three for the Yellow River Strain. This method is rapid and convenient, which offers technical support for strain identification and selective breeding in Chinese soft-shelled turtles.

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