Publications by authors named "Yang Xianle"

17 Publications

  • Page 1 of 1

Effect of Dietary Supplementation of YYL3 and YYL5 on Growth, Immune Response and Intestinal Microbiota in Channel Catfish.

Animals (Basel) 2019 Nov 20;9(12). Epub 2019 Nov 20.

Chinese Academy of Fishery Sciences, Beijing 100141, China.

The purpose of this study is to investigate the effect of probiotics YYL3 (Lc) and YYL5 (Lp) on growth performance, innate immunity, disease resistance and intestinal microbiota of channel catfish. A total of 252 catfish (67.20 ± 1.46 g) were randomly divided into 3 groups which were fed with basal diet, Lc-added (3.0 × 10 cfu/g) or Lp-added (3.0 × 10 cfu/g) diets, respectively. After 4 weeks of feeding, Lc significantly enhanced the growth and feed utilization of channel catfish compared with the control group (CG). Following that, the catfish were challenged with an intraperitoneal injection of 200 μL of the pathogenic (2.0 × 10 cfu/mL), the relative percent survival of Lc and Lp were 38.28% and 12.76%, respectively. High-throughput sequencing indicated Lc and Lp reduced the alpha diversity of the intestinal microbiota in channel catfish. were overwhelming in the guts during probiotics treatment, but almost vanished away after 2 weeks post-cessation of probiotics administration. Compared to CG, Lc and Lp resulted in an increased abundance of and decreased amount of . Functional analysis revealed that Lc treatment upregulated the relative abundance of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways including lipid metabolism, metabolism of other amino acids, metabolism of terpenoids and polyketides, xenobiotics biodegradation and metabolism, and nucleotide metabolism. Combined, our data revealed that Lc, as a feed additive at 3.0 × 10 cfu/g, could promote the growth performance, disease resistance and dramatically change the composition of intestinal microbiota of channel catfish.
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http://dx.doi.org/10.3390/ani9121005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6941169PMC
November 2019

Effect of copper sulfate on Bdellovibrio growth and bacteriolytic activity towards gibel carp-pathogenic Aeromonas hydrophila.

Can J Microbiol 2018 Dec 30;64(12):1054-1058. Epub 2018 Jul 30.

b Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, P.R. China.

The use of bdellovibrios has been regarded as an alternative to control multidrug-resistant pathogens and fish bacteriosis. However, scarce information is available on the potential of bdellovibrios in the presence of copper sulfate, which is an algicide widely used to treat cyanobacterial blooms in aquaculture. In the present study, the effects of copper sulfate at sublethal and lethal levels (0.1 and 1.0 mg·L) on Bdellovibrio sp. strain BDF-H16 were evaluated. The growth of Bdellovibrio sp. strain BDF-H16 was significantly promoted by both concentrations of copper sulfate, but less so by the lethal concentration. The bacteriolysis of gibel carp-pathogenic Aeromonas hydrophila by Bdellovibrio sp. strain BDF-H16 was also stimulated by copper sulfate in both solid and liquid media. However, Bdellovibrio sp. strain BDF-H16 with 0.1 mg·L copper sulfate clearly inhibited infection of gibel carps by A. hydrophila better than Bdellovibrio sp. strain BDF-H16 with 1.0 mg·L copper sulfate did.
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http://dx.doi.org/10.1139/cjm-2018-0165DOI Listing
December 2018

Transcriptional responses in the hepatopancreas of Eriocheir sinensis exposed to deltamethrin.

PLoS One 2017 14;12(9):e0184581. Epub 2017 Sep 14.

National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, China.

Deltamethrin is an important pesticide widely used against ectoparasites. Deltamethrin contamination has resulted in a threat to the healthy breeding of the Chinese mitten crab, Eriocheir sinensis. In this study, we investigated transcriptional responses in the hepatopancreas of E. sinensis exposed to deltamethrin. We obtained 99,087,448, 89,086,478, and 100,117,958 raw sequence reads from control 1, control 2, and control 3 groups, and 92,094,972, 92,883,894, and 92,500,828 raw sequence reads from test 1, test 2, and test 3 groups, respectively. After filtering and quality checking of the raw sequence reads, our analysis yielded 79,228,354, 72,336,470, 81,859,826, 77,649,400, 77,194,276, and 75,697,016 clean reads with a mean length of 150 bp from the control and test groups. After deltamethrin treatment, a total of 160 and 167 genes were significantly upregulated and downregulated, respectively. Gene ontology terms "biological process," "cellular component," and "molecular function" were enriched with respect to cell killing, cellular process, other organism part, cell part, binding, and catalytic. Pathway analysis using the Kyoto Encyclopedia of Genes and Genomes showed that the metabolic pathways were significantly enriched. We found that the CYP450 enzyme system, carboxylesterase, glutathione-S-transferase, and material (including carbohydrate, lipid, protein, and other substances) metabolism played important roles in the metabolism of deltamethrin in the hepatopancreas of E. sinensis. This study revealed differentially expressed genes related to insecticide metabolism and detoxification in E. sinensis for the first time and will help in understanding the toxicity and molecular metabolic mechanisms of deltamethrin in E. sinensis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0184581PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5599000PMC
October 2017

Pharmacokinetics of sulfamethoxazole and trimethoprim in Pacific white shrimp, Litopenaeus vannamei, after oral administration of single-dose and multiple-dose.

Environ Toxicol Pharmacol 2017 Jun 28;52:90-98. Epub 2017 Mar 28.

College of Aquatic and Life, Shanghai Ocean University, Shanghai 201306, PR China.

The tissue distribution and depletion of sulfamethoxazole (SMZ) and trimethoprim (TMP) were studied in Pacific white shrimp, Litopenaeus vannamei, after single-dose and multiple-dose oral administration of SMZ-TMP (5:1) via medicated feed. In single-dose oral administration, shrimps were fed once at a dose of 100 mg/kg (drug weight/body weight). In multiple-dose oral administration, shrimps were fed three times a day for three consecutive days at a dose of 100mg/kg. The results showed the kinetic characteristic of SMZ was different from TMP in Pacific white shrimp. In the single-dose administration, the SMZ was widely distributed in the tissues, while TMP was highly concentrated in the hepatopancreas. The t values of SMZ were larger and persist longer than TMP in Pacific white shrimp. In the multiple-dose administration, SMZ accumulated well in the tissues, and reached steady state level after successive administrations, while TMP did not. TMP concentration even appeared the downward trend with the increase of drug times. Compared with the single dose, the t values of SMZ in hepatopancreas (8.22-11.33h) and muscle (6.53-10.92h) of Pacific white shrimps rose, but the haemolymph dropped (13.76-11.03) in the multiple-dose oral administration. Meanwhile, the corresponding values of TMP also rose in hepatopancreas (4.53-9.65h) and muscle (2.12-2.71h), and declined in haemolymph (7.38-5.25h) following single-dose and multiple-dose oral administration in Pacific white shrimps. In addition, it is worth mentioning that the ratios of SMZ and TMP were unusually larger than the general aim ratio.
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http://dx.doi.org/10.1016/j.etap.2017.03.019DOI Listing
June 2017

Toll-like receptors and interferon associated immune factors responses to spring viraemia of carp virus infection in common carp (Cyprinus carpio).

Fish Shellfish Immunol 2016 Aug 1;55:568-76. Epub 2016 Jun 1.

Shenzhen Entry-Exit Inspection and Quarantine Bureau, Shenzhen 518045, China. Electronic address:

Pattern recognition receptor (PRR) toll-like receptors (TLRs), antiviral agent interferon (IFN) and the effector IFN stimulated genes (ISGs) play a fundamental role in the innate immune response against viruses among all vertebrate classes. Common carp is a host for spring viraemia of carp virus (Rhabdovirus carpio, SVCV), which belong to Rhabdoviridae family. The present in-vivo experiment was conducted to investigate the expression of these innate immune factors in early phase as well as during recovery of SVCV infection by real-time quantitative reverse transcriptase polymerase chain reaction. A less lethal SVCV infection was generated in common carp (Cyprinus carpio) and was sampled at 3, 6, 12 h post infection (hpi), 1, 3, 5, 7 and 10 days post infection (dpi). At 3 hpi, the SVCV N gene was detected in all three fish and all three fish showed a relative fold increase of TLR2, TLR3 and TLR7, IFNa1, ISG15 and Vig1. Viral copies rapidly increased at 12 hpi then remained high until 5 dpi. When viral copy numbers were high, a higher expression of immune genes TLR2, TLR3, TLR7, IFNa1, IFNa2, IFNa1S, IFN regulatory factor 3 (IRF3), IRF7, interleukin 1β (IL1β), IL6, IL10, ADAR, ISG15, Mx1, PKR and Vig1 were observed. Viral copies were gradually reduced in 5 to 10 dpi fish, and also the immune response was considerably reduced but remained elevated. A high degree of correlation was observed between immune genes and viral copy number in each of the sampled fish at 12 hpi. The quick and prolonged elevated expression of the immune genes indicates their crucial role in survival of host against SVCV.
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http://dx.doi.org/10.1016/j.fsi.2016.05.043DOI Listing
August 2016

Effect of common carp (Cyprinus carpio) TLR9 overexpression on the expression of downstream interferon-associated immune factor mRNAs in epithelioma papulosum cyprini cells.

Vet Immunol Immunopathol 2016 Feb 23;170:47-53. Epub 2015 Oct 23.

Shenzhen Entry-Exit Inspection and Quarantine Bureau, Shenzhen 518045, China. Electronic address:

Toll-like receptors (TLRs) are a class of pattern recognition receptors (PRRs) that recognize pathogen associated molecular patterns (PAMPs) and play an important role in the antiviral response. To determine the effect of common carp TLR9 (CcTLR9) overexpression on the expression of down-stream interferon associated immune factors in epithelioma papulosum cyprini (EPC) cells, may provide useful information for the further investigation on the anti-virus effect mediated by TLR9 in fish. In this study, we constructed an overexpression vector, pEGFP-N1-CcTLR9, by cloning the CcTLR9 gene and inserting it into an expression vector pEGFP-N1. Both plasmids DNA of pEGFP-N1 and pEGFP-N1-CcTLR9 were transfected into EPC cells, and the expression of IRF3, IRF7, ISG15, Mx1, PKR and Viperin mRNA at 0, 6, 12, 24, 48 and 72h post-transfection were determined by real-time quantitative PCR (Q-PCR). Overexpression of the CcTLR9 gene in EPC cells upregulates the expression of IRF3, IRF7, ISG15, Mx1, PKR, and Viperin mRNA, and this was more significant for Viperin, ISG15, and IRF7, and least significant for PKR. Thus, fish TLR9 activates IRF7 signaling to induce I-IFN secretion and the subsequent upregulation of IFN-stimulated genes.
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http://dx.doi.org/10.1016/j.vetimm.2015.10.006DOI Listing
February 2016

Isolation, characterization, and tissue-specific expression of GABA A receptor α1 subunit gene of Carassius auratus gibelio after avermectin treatment.

Fish Physiol Biochem 2016 Feb 29;42(1):83-92. Epub 2015 Aug 29.

National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, No. 999 Hucheng Huan Road, Lingang New City, Pudong New District, Shanghai, 201306, People's Republic of China.

Carassius auratus gibelio has been widely cultivated in fish farms in China, with avermectin (AVM) being used to prevent parasite infection. Recently, AVM was found to pass through the Carassius auratus gibelio blood-brain barrier (BBB). Although AVM acts mainly through a GABA receptor and specifically the α1 subunit gene, the most common isoform of the GABA A receptor, which is widely expressed in brain neurons and has been studied in other fish, Carassius auratus gibelio GABA A receptor α1 subunit gene cloning, and whether AVM passes through the BBB to induce Carassius auratus gibelio GABA A receptor α1 subunit gene expression have not been studied. The aim of this study was to clone, sequence, and phylogenetically analyze the GABA A receptor α1 subunit gene and to investigate the correlation of its expression with neurotoxicity in brain, liver, and kidney after AVM treatment by quantitative real-time reverse transcription polymerase chain reaction. The α1 subunit gene was 1550 bp in length with an open reading frame of 1380 bp encoding a predicted protein with 459 amino acid residues. The gene contained 128 bp of 5' terminal untranslated region (URT) and 72 bp of 3' terminal UTR. The α1 subunit structural features conformed to the Cys-loop ligand-gated ion channels family, which includes a signal peptide, an extracellular domain at the N-terminal, and four transmembrane domains. The established phylogenetic tree indicated that the α1 subunits of Carassius auratus gibelio and Danio rerio were the most closely related to each other. The α1 subunit was found to be highly expressed in brain and ovary, and the α1 mRNA transcription level increased significantly in brain. Moreover, the higher the concentration of AVM was, the higher the GABA A receptor expression was, indicating that AVM can induce significant neurotoxicity to Carassius auratus gibelio. Therefore, the α1 subunit mRNA expression was positively correlated with the neurotoxicity of AVM in Carassius auratus gibelio. Our findings suggest that AVM should be used carefully in Carassius auratus gibelio farming, and other alternate antibiotics with lower toxicity should be investigated with respect to toxicity via the induction of GABA A receptor expression for fish farming.
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http://dx.doi.org/10.1007/s10695-015-0119-9DOI Listing
February 2016

Comparison of praziquantel pharmacokinetics and tissue distribution in fresh and brackish water cultured grass carp (ctenopharyngodon idellus) after oral administration of single bolus.

BMC Vet Res 2015 Apr 1;11:84. Epub 2015 Apr 1.

College of Aquaculture and Life Science, Shanghai Ocean University, No. 999, Huchenghuan Road, Shanghai, 200090, P.R. China.

Background: Praziquantel (PZQ) is an effective pesticide against monogeneans. Its pharmacokinetics in fish may be affected by water environment and temperature. The present study was designed to compare the pharmacokinetics, tissue distribution, and elimination of PZQ in freshwater-acclimated grass carp and brackish water cultured grass carp. Plasma and tissue PZQ concentrations were determined after a single 10 mg/kg oral PZQ dose.

Results: The datas of plasma and tissues drug concentration was calculated by the software SPSS 13.0. According to the One-Way ANOVA, the results showed that the salinity had a significant effect on the drug concentration of plasma (p < 0.01), muscle (p < 0.01), liver (p < 0.01) and kidney (p < 0.01) in the all sampling time points between the brackish water grass carps and the freshwater grass carps, wherein, PZQ plasma and tissue concentrations in the brackish water group were constantly lower than that in the freshwater group. The peak PZQ levels of plasma, muscle, liver, and kidneys in the brackish water group were 0.76 μg/ml, 0.51 μg/g, 2.7 μg/g, and 2.99 μg/g, respectively; and that in the freshwater group were 0.91 μg/ml, 0.62 μg/g, 3.87 μg/g, and 3.39 μg/g, respectively. The elimination half-lives (t1/2β) in plasma and all tissues of the freshwater group were significantly longer than that in the brackish water group. The elimination half-lives (t1/2β) of plasma, muscle, liver and kidneys in brackish water grass carps were 56.46, 36.17, 15.31, and 132.64 h, respectively; and that in the freshwater grass carps were 71.15, 44.88, 23.86, and 150.23 h, respectively.

Conclusion: These findings indicate that water environment affects the tissue distribution and elimination of PZQ in grass carps, the elimination in brackish water grass carps is more rapid than that in fresh water grass carps and tissue concentrations of brackish water grass carps are lower than that in freshwater grass carps after orally administrating the same dosage at the same water temperature. We speculate that the main excretion pathway of the drug is through renal elimination, and the decreased kidney function in brackish water grass carps is likely responsible for the considerable difference in pharmacokinetics between the two groups of grass carps.
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http://dx.doi.org/10.1186/s12917-015-0400-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4389578PMC
April 2015

Relationship between permeability glycoprotein (P-gp) gene expression and enrofloxacin metabolism in Nile Tilapia.

J Aquat Anim Health 2014 Jun;26(2):59-65

a National Pathogen Collection Center for Aquatic Animals , Shanghai Ocean University , 999 Hucheng Huan Road, Shanghai , 201306 , China.

The aim of this study was to analyze the influence of permeability glycoprotein (P-gp) gene expression on enrofloxacin (ENR) metabolism in aquatic animals. Nile Tilapia Oreochomis niloticus were fed different doses of ENR ranging from 0 to 80 mg/kg. The P-gp gene expression levels were determined by quantitative real-time PCR (qRT-PCR) at indicated time points after drug administration. Drug metabolism was determined by HPLC. The P-gp gene expression in liver and kidney was greatly enhanced 30 min after ENR administration at 40 mg/kg, peaked 3 h after drug administration, and then gradually decreased. Thirty minutes after a single oral administration of ENR (0, 20, 40, or 80 mg/kg), the P-gp gene expression increased in a dose-dependent manner. The P-gp gene expression levels in the kidney were significantly higher than those in the liver. Additionally, the metabolic rate of ENR in kidney was more rapid than that in liver. Furthermore, a close correlation was found between P-gp gene expression and ENR concentrations. These results suggest that P-gp may be involved in the ENR metabolism process in Nile Tilapia, providing a novel model for the potential utility of gene expression and drug metabolism studies in aquatic animals.
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http://dx.doi.org/10.1080/08997659.2013.860059DOI Listing
June 2014

Distribution and quantitative detection of GABAA receptor in Carassius auratus gibelio.

Fish Physiol Biochem 2014 Aug 1;40(4):1301-11. Epub 2014 Apr 1.

National Center for Aquatic Pathogen Collection, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, 201306, People's Republic of China.

Gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in brain, is synthesized from glutamate and metabolized to succinic semialdehyde by glutamic acid decarboxylase (GAD) and GABA transaminase (GABA-T), respectively. The fast inhibitory effect of GABA is mediated by GABA type A (GABAA) receptors that are associated with several neurological disorders, and GABAA receptors are targets of several therapeutic agents. To date, information on the distribution and quantity of GABAA receptors in Carassius auratus gibelio is still limited. We investigated for the first time, the tissue-specific distribution of GABAARβ2a and GABAARβ2b, the two subunits of the predominant GABAA receptor subtype (α1β2γ2), and then, the expression of GABAARβ2a, GABAARβ2b, GAD, and quantified GABA-T genes in different tissues by quantitative real-time PCR method and compared different expressions between two developmental stages of C. auratus gibelio. Results showed that GABAARβ2a and GABAARβ2b genes expressed in both brain and peripheral organs using reverse transcription-polymerase chain reaction. In addition, the majority of GABAARβ2a, GABAARβ2b, GAD, and GABA-T were mainly synthesized in brain; however, a considerable amount of GABA-T was secreted from the peripheral tissues, especially in the liver. Moreover, the expression of GABAARβ2a and GABAARβ2b genes in different tissues varied with body weight change. This study provides a reference for further studies on GABA and GABAA receptors subunits and an insight on the possible pharmacological properties of the GABAA receptor in C. auratus gibelio.
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http://dx.doi.org/10.1007/s10695-014-9925-8DOI Listing
August 2014

Identification of a Proteus penneri isolate as the causal agent of red body disease of the cultured white shrimp Penaeus vannamei and its control with Bdellovibrio bacteriovorus.

Antonie Van Leeuwenhoek 2014 Feb 22;105(2):423-30. Epub 2013 Nov 22.

Key Laboratory of Freshwater Fishery Germplasm Resources, Ministry of Agriculture of P. R. China, Shanghai Engineering Research Center of Aquaculture, Shanghai University Knowledge Service Platform, Shanghai Ocean University Aquatic Animal Breeding Center (ZF1206), National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, 201306, People's Republic of China,

Bacteriosis has become a major economic problem in the farming of the Pacific white shrimp Penaeus vannamei. However, no definitive data are available about Proteus penneri infection in cultured P. vannamei and its control. In this study, a virulent strain NC was isolated from diseased P. vannamei suffering from red body disease and identified as a P. penneri isolate through phylogenetic analysis and ATB 32GN system. A phylogenetic constructed tree using the neighbour-joining method identified the NC isolate as a P. penneri strain. In addition, Bdellovibrio bacteriovorus conferred significant protection against P. penneri: it exhibited significant bacteriolytic effects on the pathogenic P. penneri, had a wide prey range towards Proteus pathogens, and displayed a good protective efficacy on experimental P. penneri infection in P. vannamei. To the best of our knowledge, this is the first report of farmed P. vannamei infected with P. penneri and its control with B. bacteriovorus.
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http://dx.doi.org/10.1007/s10482-013-0079-yDOI Listing
February 2014

Integrated pharmacokinetics/pharmacodynamics parameters-based dosing guidelines of enrofloxacin in grass carp Ctenopharyngodon idella to minimize selection of drug resistance.

BMC Vet Res 2013 Jun 25;9:126. Epub 2013 Jun 25.

Key Laboratory of Freshwater Fishery Germplasm Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, People's Republic of China.

Background: Antibiotic resistance has become a serious global problem and is steadily increasing worldwide in almost every bacterial species treated with antibiotics. In aquaculture, the therapeutic options for the treatment of A. hydrophila infection were only limited to several antibiotics, which contributed for the fast-speed emergence of drug tolerance. Accordingly, the aim of this study was to establish a medication regimen to prevent drug resistant bacteria. To determine a rational therapeutic guideline, integrated pharmacodynamics and pharmacokinetics parameters were based to predict dose and dosage interval of enrofloxacin in grass carp Ctenopharyngodon idella infected by a field-isolated A. hydrophila strain.

Results: The pathogenic A. hydrophila strain (AH10) in grass carp was identified and found to be sensitive to enrofloxacin. The mutant selection window (MSW) of enrofloxacin on isolate AH10 was determined to be 0.5-3 μg/mL based on the mutant prevention concentration (MPC) and minimum inhibitory concentration (MIC) value. By using high-performance liquid chromatography (HPLC) system, the Pharmacokinetic (PK) parameters of enrofloxacin and its metabolite ciprofloxacin in grass carp were monitored after a single oral gavage of 10, 20, 30 μg enrofloxacin per g body weight. Dosing of 30 μg/g resulted in serum maximum concentration (Cmax) of 7.151 μg/mL, and concentration in serum was above MPC till 24 h post the single dose. Once-daily dosing of 30 μg/g was determined to be the rational choice for controlling AH10 infection and preventing mutant selection in grass carp. Data of mean residue time (MRT) and body clearance (CLz) indicated that both enrofloxacin and its metabolite ciprofloxacin present similar eliminating rate and pattern in serum, muscle and liver. A withdraw time of more than 32 d was suggested based on the drug eliminating rate and pharmacokinetic model described by a polyexponential equation.

Conclusions: Based on integrated PK/PD parameters (AUC/MIC, Cmax/MIC, and T>MPC), the results of this study established a principle, for the first time, on drawing accurate dosing guideline for pharmacotherapy against A. hydrophila strain (AH10) for prevention of drug-resistant mutants. Our approach in combining PK data with PD parameters (including MPC and MSW) was the new effort in aquaculture to face the challenge of drug resistance by drawing a specific dosage guideline of antibiotics.
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http://dx.doi.org/10.1186/1746-6148-9-126DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3717066PMC
June 2013

Identification of an isolate of Saprolegnia ferax as the causal agent of saprolegniosis of yellow catfish (Pelteobagrus fulvidraco) eggs.

Vet Res Commun 2012 Dec 16;36(4):239-44. Epub 2012 Aug 16.

National Pathogen Collection Center for Aquatic Animals, Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, People's Republic of China.

Saprolegnia species have been implicated for significant fungal infections of both living and dead fish as well as their eggs. In the present study, an oomycete water mould (strain HP) isolated from yellow catfish (Peleobagrus fulvidraco) eggs suffering from saprolegniosis was characterized both morphologically and from ITS sequence data. It was initially identified as a Saprolegnia sp. isolate based on its morphological features. The constructed phylogenetic tree using neighbour joining method indicated that the HP strain was closely related to Saprolegnia ferax strain Arg4S (GenBank accession no. GQ119935), that had previously been isolated from farming water samples in Argentina. In addition, the zoospore numbers of strain HP were markedly influenced by a variety of environmental variables including temperature, pH, formalin and dithiocyano-methane. Its zoospore formation was optimal at 20 °C and pH 7, could be well inhibited by formalin and dithiocyano-methane above 5 mg/L and 0.25 mg/L, respectively. To our knowledge, this is the first report on the S. ferax infection in the hatching yellow catfish eggs.
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http://dx.doi.org/10.1007/s11259-012-9536-8DOI Listing
December 2012

Influence of hapten density on immunogenicity for anti-ciprofloxacin antibody production in mice.

Biosci Trends 2012 Apr;6(2):52-6

Shanghai Ocean University, Shanghai, China.

To generate antibodies against small molecules, it is necessary to couple them as haptens to large carriers such as proteins. However, the immunogenicity of the conjugates usually has no linear correlation with the hapten-protein ratio, which may lead to large variations in the character of the desired antibodies. In the present study, ciprofloxacin (CPFX) was coupled to bovine serum albumin (BSA) in five different proportions using a modified carbodiimide method. The conjugates were characterized qualitatively by spectrophotometric absorption and electrophoresis methods. Mass spectrometry and the trinitrobenzene sulfonic acid method were adopted to assay the density of conjugates quantitatively. As a result, CPFX-BSA conjugates with various hapten densities (21-30 molecules per carrier protein) were obtained. After immunization in mice, ELISA tests showed that the antisera titer increased gradually with the increase of hapten density. The antibody obtained from the mice showed high sensitivity toward CPFX. These results revealed the relationship between hapten density and immunogenicity as well as an optimized conjugation approach for immunization purposes.
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April 2012

A nonluminescent and highly virulent Vibrio harveyi strain is associated with "bacterial white tail disease" of Litopenaeus vannamei shrimp.

PLoS One 2012 27;7(2):e29961. Epub 2012 Feb 27.

Key Laboratory of Marine and Estuarine Fisheries Resources and Ecology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Science, Shanghai, China.

Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by "white tail" and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905) was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN), white tail disease (WTD) or penaeid white tail disease (PWTD). To differentiate from such diseases as with a sign of "white tail" but of non-bacterial origin, the present disease was named as "bacterial white tail disease (BWTD)". Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029961PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3288001PMC
August 2012

Bdellovibrios, potential biocontrol bacteria against pathogenic Aeromonas hydrophila.

Vet Microbiol 2012 Jan 4;154(3-4):413-8. Epub 2011 Aug 4.

Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources of Ministry of Education, National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai 201306, PR China.

Recent studies have revealed that the use of bdellovibrios is an alternative to control bacteriosis. However, no bdellovibrios are available against Aeromonas hydrophila infections in sturgeons. In the present study, a potential Bdellovibrio strain F16 was isolated from sturgeon gut samples, using a sturgeon-pathogenic A. hydrophila as the prey bacterium. It was initially identified as a Bdellovibrio strain using morphological characteristics and specific PCR amplification, and confirmed to be Bdellovibrio sp. strain ETB (GenBank Accession No. DQ302728) and Bdellovibrio bacteriovorus strain SRA9 (GenBank Accession No. AF263833) by phylogenetic analysis. In addition, it was shown to be safe for mammalians and sturgeons, had a wide prey range, and exhibited significant bacteriolytic effects on the pathogenic A. hydrophila. To the best of our knowledge, this is the first report on a promising gut Bdellovibrio strain against pathogenic A. hydrophila.
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http://dx.doi.org/10.1016/j.vetmic.2011.07.032DOI Listing
January 2012

A novel method for characterizing the multi-functional C-terminal domain of the Hepadnavirus core protein.

J Virol Methods 2009 Jun 6;158(1-2):195-8. Epub 2009 Feb 6.

Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China.

The Hepadnavirus core protein is a viral structural protein with an N-terminal self-assembling domain and a C-terminal protamine-like arginine-rich domain (ARD). The ARD contains four clusters of arginine residues involved in RNA binding, genome DNA synthesis, and nuclear localization. Characterization of the multi-functions of ARD has been impeded due to the insoluble nature of the core protein expressed in vitro. A GST (glutathione-S-transferase) and ARD fusion protein, GST-ARD, was expressed and purified in this study. Gel mobility shift assays using purified GST-ARD fusion proteins demonstrated that, similar to protamine, the ARD domain of the core protein bound to oligonucleotides without sequence preference. In vitro affinity chromatography binding assays showed further that the ARD bound to tested random plasmid DNA in a sequence-independent manner. The GST-ARD fusion protein-based approach can be employed further to study other biochemical properties of the core protein.
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http://dx.doi.org/10.1016/j.jviromet.2009.01.025DOI Listing
June 2009
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