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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 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.

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.

Cheng C.,Zhejiang University | Chen J.,Zhejiang Fisheries Technical Extension Center | Fang C.,Zhejiang University | Xia Y.,Zhejiang University | And 5 more authors.
Journal of Biological Chemistry | Year: 2013

Background: Listeria monocytogenes has two putative agmatine deiminase homologs, AguA1 and AguA2. Results: Only AguA1, but not AguA2, acts as functional agmatine deiminase and mediates acid tolerance in L. monocytogenes. Conclusion: Provided is the first biological insight into the roles of AgDI in acid tolerance of L. monocytogenes. Significance: We have discovered a novel residue Gly-157 other than the known catalytic triad (Cys-His-Glu/Asp) critical for L. monocytogenes AgDI activity. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.

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.

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