Okumura Takuji
National Research Institute of Aquaculture, Fisheries Research Agency, Minami-ise, Mie 516-0193, Japan.
Fish Shellfish Immunol. 2007 Jan-Feb;22(1-2):68-76. doi: 10.1016/j.fsi.2006.03.013. Epub 2006 Mar 30.
For shrimp immune defences, prophenoloxidase (proPO) activating system and antimicrobial peptides in circulating haemocytes play important roles. In the present study, the effects of lipopolysaccharide (LPS) injection on gene expression of penaeidins, crustin, serine proteinase and proPO in haemocytes were determined using real-time reverse transcription-polymerase chain reaction (PCR) in the Pacific white shrimp Litopenaeus vannamei. After injection of LPS, mRNA levels of antimicrobial peptides, penaeidin 2 (PEN2), penaeidin 3 (PEN3), penaeidin 4 (PEN4) and crustin decreased in a dose-dependent manner, while mRNA levels of serine proteinase and proPO did not change significantly. In a time-course experiment, injection of LPS caused significant depression in mRNA levels of PEN2, PEN3, PEN4 and crustin at 4h post-injection, and the depressed mRNA levels returned to initial levels by 72h post-injection. On the other hand, mRNA levels of serine proteinase and proPO did not show a significant change after injection. These results suggest that the antimicrobial peptide system responds to LPS injection at a gene expression level while the proPO system does not respond at a gene expression level.
对于虾类的免疫防御而言，循环血细胞中的酚氧化酶原（proPO）激活系统和抗菌肽发挥着重要作用。在本研究中，采用实时逆转录-聚合酶链反应（PCR）测定了脂多糖（LPS）注射对凡纳滨对虾血细胞中对虾素、甲壳素、丝氨酸蛋白酶和酚氧化酶原基因表达的影响。注射LPS后，抗菌肽对虾素2（PEN2）、对虾素3（PEN3）、对虾素4（PEN4）和甲壳素的mRNA水平呈剂量依赖性下降，而丝氨酸蛋白酶和酚氧化酶原的mRNA水平没有显著变化。在一项时间进程实验中，注射LPS导致注射后4小时PEN2、PEN3、PEN4和甲壳素的mRNA水平显著降低，且降低的mRNA水平在注射后72小时恢复到初始水平。另一方面，注射后丝氨酸蛋白酶和酚氧化酶原的mRNA水平没有显著变化。这些结果表明，抗菌肽系统在基因表达水平上对LPS注射有反应，而酚氧化酶原系统在基因表达水平上没有反应。
