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.
Zhou
Jun
J
Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, College of Life Science, South China Normal University, Guangzhou 510631, PR China.
Wang
Wei-Na
WN
Wang
An-Li
AL
He
Wen-Yin
WY
Zhou
Qi-Ting
QT
Liu
Yuan
Y
Xu
Jie
J
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