Effects Of Tannin Acid On The Metabolism Of Brandt’S Voles (Lasiopodomys Brandtii)

The co-evolution between herbivorous animals and plants is one of the main points of biological research. Herbivorous Animals need to feed on plants for their survival. But the plants produce a variety of plants second metabolites (PSMs) to hinder the feeding of animal. Then, the animals change their metabolism style to adapt the PSMs in food. Brandt’s vole is one of herbivorous mammals inhabiting in Inner Mongolia and feed on plants with high amount of PSMs. The aim of this study was to investigate the effect of PSMs on some important enzymes or proteins of Brandt’s vole after they were given food with3%tannin acid for37days. At first, the change of their salivary proteins was observed by SDS gel electrophoresis and the content of amino acids in saliva and feces were assayed using amino acid analyzer. Secondly, the enzyme activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) in liver of Brandt’s vole was determined and the content of SOD and GPx was measured by western blot method. Thirdly, the full length of the gene of3-hydroxy-3-methyl coenzyme A reductase (HMGCR), the key enzyme of the biosynthesis of cholesterol, was cloned. The expression of this gene detected by fluorescence quantitative real-time PCR and the content of this protein was measured by western blot method. Finally, the partial cDNA sequence of transferrin (Trf) was amplified and its transcription was checked, as well as its translation. The results were as follows.The result of SDS gel electrophoresis showed that new protein band was observed in the saliva of Brandt’s voles after they were treated by tannin acid. And both of proline and histidine increased significantly in their saliva and feces.Treating with tannin acid also induced the increasing of the amount of GPx and the enzyme activity of CAT, SOD, GR and GPx in liver of vole.And the full length cDNA of HMGCR of Brandt’s voles was obtained by combining the sequence amplified by degenerate primers with the sequence obtained by3’RACE and5’RACE technique. It was2633bp, encoding876amino acid residues. The homology of these amino acids with the amino sequence of HMGCR in both of Chinese hamster and gold hamster was96%. The transcription of HMGCR was reduced after the animals treated by tannin acid, same as the translation of this enzyme.We also got the partial sequence of cDNA of Trf in Brandt’s voles,which was427bp and encoded141amino acids. The similarity of these amino sequences with the amino sequence of Trf in Chinese hamster was86%. Both of the transcription and translation of this protein was enhanced by tannin acidAll of these suggested that tannin acid could influence the metabolism of Brandt’s voles. It could inhibit the biosynthesis of cholesterol by reduce the expression of HMGCR. But Brandt’s voles could secret salivary proline-rich proteins, which can bind to tannin acid in food, to reduce the bind of tannin acid to the digestive enzymes in alimentary canal and to lessen the influence of tannin acid on their assimilation of food. Taking tannin acid also enhanced the antioxidation ability of voles by increasing the amount and activity of their antioxidative enzymes. And to ensure iron-binding enzymes and proteins have normal activity, voles absorb more iron by increasing the expression of transferrin. In a words, Brandt’s voles could adapt to the change of the tannin acid in food by regulate their own metabolism. These results would be useful to elucidate the co-evolution between the animals and plants.