clpV is a key virulence gene during in vivo Pseudomonas plecoglossicida infection     

Gang Luo  Xiaojin Xu  Lingmin Zhao  Yingxue Qin  Lixing Huang  Yongquan Su  Qingpi Yan 《Journal of fish diseases》2019,42(7):991-1000

Interaction between bacterial pathogen and aquatic animal host is exceedingly complex, which involves large dynamic changes in gene expression during different stages of the disease. However, research on identifying key virulence genes based on the dynamics of gene expression changes of a one‐sided bacterial pathogen in tissue has not been reported so far across different stages of infectious disease. The clpV for the T6SS of Pseudomonas plecoglossicida was identified for a candidate for key virulence gene based on dynamic changes of gene expression. For the Epinephelus coioides infected using clpV‐RNAi strain, no deaths were observed up to 20 dpi. The spleens, kidneys and livers of all the E. coioides that received clpV‐RNAi strain failed to develop visible nodules at 5–8 dpi, with the swelling gradually disappearing. The burdens of clpV‐RNAi strain in the spleen and blood were greatly reduced at most of the time points after injection, and the burdens of clpV‐RNAi strain in the head kidneys and trunk kidneys also had a sharp reduction from 72 to 120 hpi. This paper provides a new insight into the discovery of key virulence genes of pathogens in infected tissue systems.  相似文献   

广西工厂化循环水养殖石斑鱼水质处理效果   总被引：1，自引：0，他引：1  

刘旭佳  王志成  熊向英  梁志辉  王贤丰  姚坤志 《渔业现代化》2019,(2):22-27

通过集成海水养鱼、生化处理、设施工程、环境工程、电器自控和水质监控等技术,建立一套适合广西地区应用的工厂化循环水石斑鱼养殖系统。该养殖系统处理流程为:鱼池→沉淀池→蛋白质分离器→生物滤池→海马齿浮床→紫外杀菌,生物滤池包括A、B、C三个通道,A、B通道均由珊瑚石作为一、二级生物过滤和生化球作为三级过滤,C通道由珊瑚石作为一级过滤和椰子壳碎作为二、三级过滤。结果显示:沉淀池处理可以显著降低鱼池的COD,氨氮、亚硝酸盐氮、硝酸盐氮和磷酸盐的质量浓度(P<0.05);经海马齿浮床系统处理后,硝酸盐氮质量浓度显著低于沉淀池、蛋白质分离器处理池、生物滤池A、B通道(P<0.05);整体上,C通道水质指标略低于A、B通道,但差异不明显(P>0.05)。该研究结果可为广西沿海发展循环水养殖技术以及养殖生产方式转变提供可靠的科学数据和技术参考。  相似文献   

Vibrio harveyi (VirB11) recombinant vaccine development against vibriosis in orange‐spotted grouper (Epinephelus coioides)     

Denicia Atujona  Yucong Huang  Zhiwen Wang  Jichang Jian  Shuanghu Cai 《Aquaculture Research》2019,50(9):2628-2634

Despite significant improvements in aquaculture to compensate wild catch, disease organisms have thrived in limiting its national and global potential. Using antibiotics, in a bid to remedy the havoc, has given rise to complications, attracting attention to disease prevention by immune enhancement against diseases. Grouper production has been inhibited for the threats of bacterial infection, particularly of Vibrio origin. Considering the rise in vibriosis cases, improved vaccines are necessary; moreover, recombinant vaccines, the choice for trial in the present experiment have been effective and more specific in improving immunity. The current work deals with grouper immune system enhancement with a recombinant vaccine developed from VirB11 gene in Vibrio harveyi. VirB11 was cloned in V. harveyi for recombinant vaccine development against vibriosis in orange‐spotted grouper (Epinephelus coioides). As indicated by the results, recombinant VirB11 protein showed effectiveness in conferring protection against vibriosis with observable specific antibody response in enzyme‐linked immunosorbent assay (ELISA) analysis; a significant increase (p < 0.05) in antibody levels was observed after a week and after 8 weeks post‐vaccination. From the weeks post‐vaccination, log2 (antibody titres) in the sera of vaccinated groups reached a peak of 14.2 at week 5 in the vaccinated group in comparison with a peak of approximately 5 and 2 in adjuvant and PBS controls. As indicated by the challenge results, 90% relative survival was observed in vaccinated group and 13% relative survival in control group I (adjuvant control). The cumulative performance of protein concludes VirB11 commendable for recombinant vaccine development.  相似文献   

真鲷虹彩病毒自然感染杂交石斑鱼“褐龙斑”的组织病理分析          下载免费PDF全文

刘冉阳  史成银  谢国驷  李晨  王海波 《渔业科学进展》2019,40(3):103-112

褐龙斑是雌性褐石斑鱼(Epinephelus bruneus)和雄性鞍带石斑鱼(E. lanceolatus)杂交产生的子代。作为杂交石斑鱼的新品种,国内外尚没有褐龙斑疾病的报道。2017年7月,某养殖场褐龙斑出现急性死亡,10 d内累积死亡率高达80%。现场调查发现,病鱼外观无明显异常,但反应迟钝,伏底死亡。临床检查和剖检可见脾和肾严重肿大、易碎。组织病理切片观察发现,各组织中存在数量不等的嗜碱性、细胞质均一、直径为10~15 µm的肿大细胞。超薄组织切片中发现,肿大细胞胞质内存在大量直径为130~150 nm的虹彩病毒样颗粒。使用特异性的PCR引物,从病鱼脾、头肾等组织中均检测到真鲷虹彩病毒(Red seabream iridovirus, RSIV)的高强度感染。测定了该病毒主要衣壳蛋白(Major capsid protein, MCP)基因1362 bp的全长编码区,构建了19种(株)虹彩病毒系统发育树,结果显示,该病毒属于虹彩病毒科肿大细胞病毒属RSIV类群。本研究首次描述了褐龙斑虹彩病毒病的组织病理特征,揭示了褐龙斑是RSIV新的敏感宿主,为杂交石斑鱼病毒病的诊断与防治提供了重要的参考依据。  相似文献   

Protection conferred against viral nervous necrosis by simultaneous inoculation of aquabirnavirus and inactivated betanodavirus in the sevenband grouper, Epinephelus septemfasciatus (Thunberg)     

H Yamashita  K Mori  T Nakai 《Journal of fish diseases》2009,32(2):201-210

An aquabirnavirus (ABV) and a formalin-inactivated betanodavirus [redspotted grouper nervous necrosis virus (RGNNV)] were investigated for their potential to prevent RGNNV-induced viral nervous necrosis (VNN) in the sevenband grouper, Epinephelus septemfasciatus (Thunberg). Three groups of fish were injected intramuscularly with ABV, intraperitoneally with inactivated RGNNV (iRGNNV) or with both ABV and iRGNNV. At 3, 7, 14, 21 and 28 days post-injection (p.i.), fish were challenged by intramuscular injection of RGNNV. Control fish, which received neither ABV nor iRGNNV, showed high mortalities in all RGNNV challenges. Fish that received only ABV exhibited relative percent survival (RPS) of >60 against RGNNV challenges at 3, 7, 14 and 21 days p.i., but not at 28 days p.i., while fish that received only iRGNNV showed significantly higher protection against RGNNV challenges only at 21 and 28 days p.i. In contrast, fish that received both ABV and iRGNNV showed 60 or higher RPS against all RGNNV challenges. Fish inoculated with iRGNNV with or without ABV exhibited similar high titres of neutralizing antibodies to RGNNV at 14, 21 and 28 days p.i. These results indicate that combined inoculation with iRGNNV and ABV conferred both rapid non-specific and delayed specific protection against VNN.  相似文献   

斜带石斑鱼溶藻弧菌病的研究   总被引：4，自引：0，他引：4  

黄瑞芳 《水产科学》2005,24(6):1-3

从患病的斜带石斑鱼肝和肾组织分离的两株病原菌,进行纯化培养、人工感染、VITEK-AMS-32自动微生物分析鉴定及药敏试验,经形态和生理生化测定,确定为溶藻弧菌(Vibrioalginolyticus)。组织病理变化主要表现为鳃、肝和肾细胞变性、坏死,病变组织炎性细胞浸润,呈变质性炎症。  相似文献   

LHRH-A缓释剂促进雄性赤点石斑鱼性类固醇激素分泌和精巢发育与排精的研究   总被引：3，自引：0，他引：3  

舒琥 《水产学报》2005,29(4):433-440

研究了促黄体生成素释放激素类似物(LHRHA)不同处理方式对雄性赤点石斑鱼性类固醇激素分泌和精子生成及精子排放的影响。对照组在0、7d二次注射生理盐水(50μg·kg-1BW),注射组在0、7d二次注射LHRHA(50μg·kg-1BW),埋植组在0d埋植LHRHA缓释剂(100μg·kg-1BW)。结果表明,通过埋植LHRHA缓释剂,血清睾酮(T)和11-酮基睾酮(11-KT)水平快速增加,显示血清睾酮和11-酮基睾酮水平与赤点石斑鱼精子生成和精子排放有密切关系。组织学观察表明,在21d,对照组和注射组鱼精巢充满了精子细胞、精母细胞和精原细胞,而在同一时间,LHRHA埋植组鱼精巢含有大量精子,表明精子排放仍在进行。在40d期间采集精液总量为对照组<注射组<埋植组,差异显著。当注射组在处理14d后精液量逐渐回落到对照组水平时,埋植组仍然维持较高精液量水平。各组采集的精子的活力与采集的精液量呈正相关,而精子密度没有显著差异。数据显示,LHRHA缓释剂能显著增加赤点石斑鱼的精液量及延长精子排放时间而不改变精子的质量。  相似文献   

Supplementation of heat‐inactivated Bacillus clausii DE5 in diets for grouper,Epinephelus coioides,improves feed utilization,intestinal and systemic immune responses and not growth performance          下载免费PDF全文

J. Wang  H.‐L. Yang  H.‐Q. Xia  J.‐d. Ye  K.‐L. Lu  X. Hu  Y. Feng  L. Ruan  Y.‐Z. Sun 《Aquaculture Nutrition》2018,24(2):821-831

In recent years, more and more attentions have been paid to the development and application of probiotics in aquaculture, and viable probiotics have been extensively studied, while rare information was available about inactivated probiotics in aquaculture. Therefore, in this study, a feeding trial was designed to investigate the effect of dietary supplementation of heat‐inactivated probiotic Bacillus clausii DE5 on growth performance, immune response and key immune genes expression in head kidney and intestine in grouper Epinephelus coioides. Fish were fed for 60 days with control diet (C) and two experimental diets containing 1.0 × 10⁸ CFU/g live (T1) and heat‐inactivated (T2) B. clausii DE5, respectively. The probiotic treatments did not affect the final weight, weight gain (WG) and specific growth rate (SGR) of E. coioides at days 30 and 60 (p > .05), while both heat‐inactivated and live B. clausii DE5 significantly decreased the feed intake and feed conversion ratio (FCR) at day 60 (p < .05). Serum lysozyme activity and complement C3 level in the two probiotic treatments were significantly higher than those in the control (p < .05). The lysozyme activity and complement C3 level at day 60 were significantly higher than those at day 30 (p < .05), while no significant interaction effect between diet and administration date was observed. Moreover, the heat‐inactivated B. clausii DE5 significantly improved the expression of TLR5, pro‐inflammatory cytokines (IL‐8 and IL‐1β) and TGF‐β1 in head kidney and intestine (p < .05), while the live probiotic did not show any significant effect on the expression of these key immune‐related genes in head kidney and intestine. These results indicate that dietary supplementation of heat‐inactivated B. clausii DE5 effectively improved feed utilization and both the local and systemic immune responses of E. coioides.  相似文献   

Effects of rhythmic temperature change on the growth,body composition and energy budget of hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀)          下载免费PDF全文

Rui‐Peng He  Xiang‐Li Tian  Jie Feng  Shuang‐Lin Dong  Bin Wen 《Aquaculture Research》2018,49(2):874-881

Effects of rhythmic temperature change on the growth, body composition and energy budget of hybrid grouper (Epinephelus lanceolatus ♂ × E. fuscoguttatus ♀) were investigated. Nine groups of fish received repeating cycles of low‐temperature manipulation (22°C) for 1, 2 and 4 days followed by recovery temperature (28°C) for (3, 7 and 11 days), (6, 14 and 22 days) and (12, 28 and 44 days) respectively, designated as L1R3, L1R7, L1R11, L2R6, L2R14, L2R22, L4R12, L4R28 and L4R44 respectively. In the control group (C), fish were reared at 28°C throughout the whole experiment. After 96‐day feeding trail, the final weight, relative weight gain rate, specific growth rate, food conversion efficiency and apparent digestibility coefficient of fish in L4R28 were significantly higher than those of control (p < .05). The crude protein contents of fish in L2R14, L2R22, L4R12, L4R28 and L4R44 were significantly higher compared to the control (p < .05). According to energy budget, fish in L4R28 exhibited significantly higher proportion of food energy assimilated into growth and lower proportion consumed for excretion than the control fish (p < .05). These results indicated the occurrence of complete or over growth compensation in hybrid grouper, and the use of repeated cycles of low temperature (22°C) for 4 days followed by recovery temperature (28°C) for 28 days could obtain enhanced growth, that is overcompensation, with improved apparent digestibility coefficient, food conversion efficiency and energetic efficiency into growth. This technique would be more practically applicable in indoor culture for this species.  相似文献   

斜带石斑鱼肝细胞分离及原代培养方法的建立   总被引：2，自引：2，他引：0  

骆源  张春晓  王玲  张冬玲  霍振华  宋凯 《水产学报》2016,40(4):558-565

本研究以斜带石斑鱼肝细胞为实验对象,在不同培养条件下进行原代培养,旨在探讨稳定可靠的斜带石斑鱼肝细胞分离及原代培养方法。采用组织块分离法和胰蛋白酶(含EDTA)消化法分离肝细胞,并通过密度梯度离心法分离纯化肝细胞,细胞悬液于DMEM/F-12、M199和L-15培养液中培养;细胞活力及数量采用血球计数板计数,并通过MTT法测定细胞增殖率;同时,测定不同时间培养上清液中乳酸脱氢酶(LDH)活性、白蛋白(ALB)和尿素氮(BUN)的含量,以分析肝细胞生长状态。结果表明,组织块方法不适于斜带石斑鱼肝细胞的培养,未见细胞从组织块中迁出,而胰蛋白酶消化法获得良好稳定的培养效果,细胞产量达到1.6×108个/g肝重,活细胞数达到95%;L-15培养基细胞生长明显优于DMEM/F-12和M199培养基;启动原代培养的48~72 h阶段肝细胞生长代谢旺盛,培养上清液中LDH活性显著降低,ALB和BUN含量显著升高。结果显示,0.25%的胰蛋白酶常温消化法适合斜带石斑鱼肝细胞的分离,斜带石斑鱼肝细胞原代培养的最适培养基为L-15培养基,肝细胞在启动原代培养的48~72 h生长代谢旺盛。  相似文献