摘要： 为研究吉富罗非鱼感染无乳链球菌后肝脏组织多肽表达变化，采用串联飞行时间质谱仪（MALDI-TOF/TOF）扫描了吉富罗非鱼感染无乳链球菌24 h后与未感染的罗非鱼肝脏组织的多肽质谱峰值差异，并对表达差异的多肽峰值进行蛋白质质谱鉴定和功能分类。结果显示：对照组检测到信噪比（s/n）大于50的质谱峰为44个，试验组为52个，发现6个质谱峰（m/z 1 082，1 161，1 196，1 459，1 740，1 877）在感染24 h后与未感染鱼之间的表达差异明显，其中质荷比（m/z）1 196在试验组表达下降，而质荷比（m/z）1 161和1 459则是上升。共鉴定得到19种多肽，其中14个表达上调，4个下调，1个无明显变化。经生物信息学分析，鉴定得到的多肽分别参与了三羧酸循环、DNA拼接和细胞防御3条信号调控通路。选择其中的ATP合成酶6（ATP6）和beta-羟基丁酸脱氢酶（Bhd1）基因进行qRT-PCR验证，发现ATP6基因在感染24 h后的转录水平显著升高，而Bhd1基因的转录水平则是显著降低，与多肽组相对定量的结果相符。研究结果为无乳链球菌病的早期诊断提供了新的参考依据。

关键词: 吉富罗非鱼, 无乳链球菌, 多肽, 差异表达

Abstract: The polypeptide expression on GIFT tilapia liver was studied after infecting Streptococcus agalactiae.Matrix-assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) was employed to analyze the polypeptide,and they were identified by mass spectrometry.The results indicated that there were 44 and 52 polypeptide between control group and experimental group,which Signal/Noise (s/n) was more than 50.We discovered 6 peaks (m/z 1 082, 1 161,1 196,1 459,1 740,1 877) was obvious difference in two groups(P<0.01).The 1 196(m/z) peptide decreased,but the 1 161 and 1 459(m/z) peptide increased in experimental group.All the mass spectrums were corresponding to 19 peptides,and 14 shows a up-regulated expression,4 shows down-regulated expression,and 1 shows no obvious change.The results of bioinformatical analysis indicated that all the peptides were involved in three regulation pathways including TCA cycle,DNA splice and cell defensive signaling pathway.Real-time PCR was utilized to analysis the mRNA variation of ATP synthase 6 (ATP6) gene and D-beta-hydroxybutyrate dehydrogenase (Bhd1) gene.The results confirmed the positive correlation of gene expression and protein expression.The results of peptidome analysis provided a new approach to diagnose the Streptococcus agalactiae disease.

Key words: GIFT tilapia, Streptococcus agalactiae, Polypeptide, Differential expression

中图分类号: 

• Q78