Variation of phenoloxidase activity affected by hemocyanin in shrimp Penaeus vannamei

以采自厦门的南美白对虾(Penaeusvannamei)为研究对象,运用病原菌人工感染、血蓝蛋白浓度和酚氧化酶(phenoloxidase,PO)活性测定等方法探索南美白对虾血蓝蛋白在体内、外对其血清酚氧化酶活性的影响。结果表明,南美白对虾人工感染副溶血弧菌后,其血淋巴中血蓝蛋白浓度和PO活性的变化趋势基本一致。在体外实验中将一定量的血蓝蛋白重组蛋白添加至血清中,其PO活性可明显升高;但同时添加血蓝蛋白重组蛋白和E.coliK12超声破碎液后,其PO活力反而降低。研究提示,血蓝蛋白在一定范围内确实可以正反馈调节PO活性,但在细菌等干扰之下,其又可表现出一定的负反馈抑制活性。It has been confirmed that hemocyanin is a kind of important multifunctional protein found in the hemolymph of both arthropod and mollusk. And phenoloxidase is a type of vital immune protein in invertebrate. Recently,interest has been focused on comparative research between hemocyanin and phenoloxidase. In the paper,a preliminary study was made to characterize the variation of phenoloxidase activity affected by in vivo hemocyanin and in vitro hemocyanin recombinant protein in shrimp Penaeus vannamei obtained from Xiamen. The methods of artificial infection by V. parahaemolyticus and measurement of both concentration of hemocyanin and phenoloxidase activity were used. The results showed that the variational trend of hemocyanin's concentration was similar to that of phenoloxidase activity after the shrimp was infected by V. parahaemolyticus,both of which increased to their maximum in 24?h,then descended slowly,finally came back to normal level in 36?h. In comparison with control group in vitro, the shrimp serum's phenoloxidase activity increased obviously after hemocyanin recombinant protein was added in at the concentration of 200?μg/mL or ultrasonic solution of E. coli K12 at the concentration of 35?mg/mL. However,when both hemocyanin recombinant protein and ultrasonic solution of E. coli K12 were added into the shrimp serum, its phenoloxidase activity descended immediately. It suggests that hemocyanin can adjust the phenoloxidase activity by means of positive feedback,but it also can adjust the phenoloxidase activity by means of negative feedback when its reactive solution is involved in some bacteria. In summary,these results are the latest discovery in the field of the immune function of hemocyanin and phenoloxidase,which will be helpful for elucidating the immune mechanism of hemocyanin and interrelation between hemocyanin and phenoloxidase.国家“863”计划项目基金(2002AA629050);; 广东省自然科学基金(博士启动基金)资助项目(130-122187).~

Preliminary Study on the Interaction between Hemocyanin inShrimp Penaeus vannamei and Anti_human IgG Antibody

以采自汕头的南美白对虾血清为研究对象, 运用Sephdex_75 柱层析、PAGE、Dot_ELISA、SDS_PAGE和Western_blotting等方法, 探索血蓝蛋白与抗人IgG之间的相互作用. 结果表明, 血蓝蛋白不仅可与兔抗虾血蓝蛋白抗血清发生特异性的结合, 也可与抗人IgG发生明显的交叉反应. 进一步研究显示, 血蓝蛋白表现为相对分子质量分别为75 kDa和73kDa的两个亚基, 其中75 kDa亚基与抗人IgG呈显著阳性, 表明, 血蓝蛋白75 kDa亚基与人Ig存在相似的抗原决定簇或高度同源的同源区域.In the paper,a preliminary study was made to analyze the interaction between hemocyanin, which was purified from shrimp P.vannamei obtained from Shantou,and anti-human antibody.The methods of Sephadex G-75 column chromatography,PAGE,Dot_ELISA, SDS_PAGE and Western_blotting were used. The results showed that hemocyanin not only could be specifically reacted with rabbit anti_shrimp hemocyanin antibody, but also peculiarly bound with goat anti_human antibody.Furthermore, hemocyanin appeared two subunit with Mr of 75kDa and 73kDa,respectively,of which only the protein with 75kDa was documented to be positive.The hemocyanin subunit with 75kDa probably shares similar epitopes or homologous motifs with human Ig.广东省自然基金(博士启动基金)资助项目(No: 130_122187);; 厦门大学细胞生物学与肿瘤细胞工程教育部重点实验室资助项目(No: 2004101

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies