Glutathione S-transferase in the white shrimp Litopenaeus vannamei: Characterization and regulation under pH stress.
We first expressed a Mu-class GST from white shrimp Litopenaeus vannamei in Escherichia coli, and then characterized the purified recombinant enzyme with respect to the effects of pH, temperature on its catalytic (1-chloro-2, 4-dinitrobenzene-glutathione conjugation) activity. We also analyzed its expression profile in L. vannamei tissues, and assessed changes in Mu-GST expression, GST activity profiles and mortality rates following exposure of white shrimp to low and high pH (5.6 and 9.3, respectively). Realtime-PCR analysis showed that Mu-GST transcripts were expressed in all examined L. vannamei tissues, but were most abundant in the hepatopancreas. At low pH Mu-GST transcript levels in the hepatopancreas were highest after 12 h, and then declined to their original levels after 24 h. After 12 h they were also upregulated in haemocytes, but downregulated in the gills, and unchanged in the stomach following exposure to pH stress. Western blot analyses confirmed that the Mu-GST protein was strongly expressed in the hepatopancreas after 12 h at low pH and remain unchanged in the stomach after exposure to pH stress. pH-Related changes in GST activities in the shrimp hepatopancreas were similar to those displayed by the Mu-GST mRNA and protein profiles. In addition, the mortality of L. vannamei was higher at high pH than at low pH. These results suggest that L. vannamei Mu-GST expression is stimulated by acidic pH and that it may play important roles in detoxification of xenobiotics and antioxidant defenses.
Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, College of Life Science, South China Normal University, Guangzhou 510631, PR China.
Jun
J
Zhou
Wei-Na
WN
Wang
An-Li
AL
Wang
Wen-Yin
WY
He
Qi-Ting
QT
Zhou
Yuan
Y
Liu
Jie
J
Xu
D000818:Animals; D003001:Cloning, Molecular; D004137:Dinitrochlorobenzene / Q000378:metabolism; D004795:Enzyme Stability; D015971:Gene Expression Regulation, Enzymologic; D005880:Gills / Q000201:enzymology; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D006434:Hemocytes / Q000201:enzymology; D006458:Hemolymph / Q000201:enzymology; D043143:Hepatopancreas / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D033561:Penaeidae / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D013270:Stomach / Q000201:enzymology; D013312:Stress, Physiological; D013379:Substrate Specificity; D013696:Temperature; D013997:Time Factors
C042630:1-chloro-2,4-dinitrobenzene-glutathione conjugate; D004137:Dinitrochlorobenzene; D011994:Recombinant Proteins; D005982:Glutathione Transferase; D005978:Glutathione