Gayal is a rare semi-wild bovine species found in the Indo-China. They can graze grasses, including bamboo leaves, as well as reeds and other plant species, and grow to higher mature live weights than Yunnan Yellow ca...Gayal is a rare semi-wild bovine species found in the Indo-China. They can graze grasses, including bamboo leaves, as well as reeds and other plant species, and grow to higher mature live weights than Yunnan Yellow cattle maintained in similar harsh environments. The aim of this study was to identify specific cellulase in the gayal rumen. A metagenomic fosmid library was constructed using genomic DNA isolated from the ruminal contents of four adult gayals. This library contained 38400 clones with an average insert size of 35.5 kb. The Umcel-1 gene was isolated from this library. Investigation of the cellulase activity of 24 random clones led to the identification of the Umcel-1 gene, which exhibited the most potent cellulase activity. Sequencing the Umcel-1 gene revealed that it contained an open reading frame of 942 base pairs that encoded a product of 313 amino acids. The putative gene Umcel-1 product belonged to the glycosyl hydrolase family 5 and showed the highest homology to the cellulase （GenBank accession no. YP_004310852.1 ） from Clostridium lentocellum DSM 5427, with 44% identity and 62% similarity. The Umcel-1 gene was heterologously expressed in Escherichia coil BL21, and recombinant Umcel-1 was purified. The activity of purified recombinant Umcel-1 was assessed, and the results revealed that it hydrolyzed carboxymethyl cellulose with optimal activity at pH 5.5 and 45~C. To our knowledge, this study provides the first evidence for a cellulase produced by bacteria in gayal rumen.展开更多
To investigate the anaerobic fungal diversity in the rumen of gayals(Bos frontalis), Yunnan yellow cattle, yaks, and Tibetan yellow cattle, the ITS region of ruminal anaerobic fungi was sequenced. The anaerobic fungi ...To investigate the anaerobic fungal diversity in the rumen of gayals(Bos frontalis), Yunnan yellow cattle, yaks, and Tibetan yellow cattle, the ITS region of ruminal anaerobic fungi was sequenced. The anaerobic fungi found in four types of cattle could be divided into 16 groups(Neocallimastix, Anaeromyces, Orpinomyces, Caecomyces, Cyllamyces and unknown groups 1-11). There were 10 anaerobic fungal groups in the rumen of gayals, with three belonging to known genera(Orpinomyces, Neocallimastix, and Caecomyces), which accounted for 2.8% of sequences of gayals. There were fewer known anaerobic fungi in gayals than in Yunnan yellow cattle(Orpinomyces), yaks(Anaeromyces, Orpinomyces, and Cyllamyces) and Tibetan yellow cattle(Anaeromyces, Orpinomyces, Caecomyces, and Cyllamyces), accounting for 30.7%, 93.9%, and 35% of each of the relevant cattle species. The other seven unknown groups(NG1, NG4, NG6, NG7, NG9, NG10, and NG11) accounted for 91.6% of sequences from gayals, which was higher than Yunnan yellow cattle [69.3%(NG2, NG8 and NG9)], Tibetan yellow cattle [35%(NG4, NG5 and NG9)], and yaks [6.1%(NG3)]. Furthermore, NG1, NG6, NG7, NG10, and NG11 were only found in gayals,whereas NG3 and NG5 were found only in Tibetan yellow cattle and yak, respectively. Piromyces was not found in any of the four types of cattle. The anaerobic fungi abundance in the rumen of gayals was significantly higher than that of the other three types of cattle. The ruminal anaerobic fungi of gayals might have an important role in cellulose degradation, resulting in the ability of this species to successfully graze coarser fodder.展开更多
基金supported by the National Natural Science Foundation of China (31160467, 31360562, 31160449 and 31260543)
文摘Gayal is a rare semi-wild bovine species found in the Indo-China. They can graze grasses, including bamboo leaves, as well as reeds and other plant species, and grow to higher mature live weights than Yunnan Yellow cattle maintained in similar harsh environments. The aim of this study was to identify specific cellulase in the gayal rumen. A metagenomic fosmid library was constructed using genomic DNA isolated from the ruminal contents of four adult gayals. This library contained 38400 clones with an average insert size of 35.5 kb. The Umcel-1 gene was isolated from this library. Investigation of the cellulase activity of 24 random clones led to the identification of the Umcel-1 gene, which exhibited the most potent cellulase activity. Sequencing the Umcel-1 gene revealed that it contained an open reading frame of 942 base pairs that encoded a product of 313 amino acids. The putative gene Umcel-1 product belonged to the glycosyl hydrolase family 5 and showed the highest homology to the cellulase （GenBank accession no. YP_004310852.1 ） from Clostridium lentocellum DSM 5427, with 44% identity and 62% similarity. The Umcel-1 gene was heterologously expressed in Escherichia coil BL21, and recombinant Umcel-1 was purified. The activity of purified recombinant Umcel-1 was assessed, and the results revealed that it hydrolyzed carboxymethyl cellulose with optimal activity at pH 5.5 and 45~C. To our knowledge, this study provides the first evidence for a cellulase produced by bacteria in gayal rumen.
基金Supported by the National Natural Science Foundation of China(31672452)the Natural Science Foundation of Yunnan Province(2014FA033)the Foundation of Yunnan Provincial Key Laboratory of Animal and Feed Science(DYCX2015001)
文摘To investigate the anaerobic fungal diversity in the rumen of gayals(Bos frontalis), Yunnan yellow cattle, yaks, and Tibetan yellow cattle, the ITS region of ruminal anaerobic fungi was sequenced. The anaerobic fungi found in four types of cattle could be divided into 16 groups(Neocallimastix, Anaeromyces, Orpinomyces, Caecomyces, Cyllamyces and unknown groups 1-11). There were 10 anaerobic fungal groups in the rumen of gayals, with three belonging to known genera(Orpinomyces, Neocallimastix, and Caecomyces), which accounted for 2.8% of sequences of gayals. There were fewer known anaerobic fungi in gayals than in Yunnan yellow cattle(Orpinomyces), yaks(Anaeromyces, Orpinomyces, and Cyllamyces) and Tibetan yellow cattle(Anaeromyces, Orpinomyces, Caecomyces, and Cyllamyces), accounting for 30.7%, 93.9%, and 35% of each of the relevant cattle species. The other seven unknown groups(NG1, NG4, NG6, NG7, NG9, NG10, and NG11) accounted for 91.6% of sequences from gayals, which was higher than Yunnan yellow cattle [69.3%(NG2, NG8 and NG9)], Tibetan yellow cattle [35%(NG4, NG5 and NG9)], and yaks [6.1%(NG3)]. Furthermore, NG1, NG6, NG7, NG10, and NG11 were only found in gayals,whereas NG3 and NG5 were found only in Tibetan yellow cattle and yak, respectively. Piromyces was not found in any of the four types of cattle. The anaerobic fungi abundance in the rumen of gayals was significantly higher than that of the other three types of cattle. The ruminal anaerobic fungi of gayals might have an important role in cellulose degradation, resulting in the ability of this species to successfully graze coarser fodder.
