Exploration of the effects of altitude change on bacteria and fungi in the rumen of yak (Bos grunniens).

The yak (Bos grunniens) is a ruminant animal with strong regional adaptability. However, little is known about the adaptation of the rumen microbial community of yaks at different altitudes and the adaptation mechanism of the host and intestinal microorganisms to the habitat. We investigated the adaptability of the rumen microorganisms of yaks at high and low altitudes. We also compared and analyzed the abundance and diversity of core microorganisms and those that varied between different animals. The aim was to compare the rumen bacterial and fungal communities of grazing yak living at two elevations. Bacteroidetes, Firmicutes, Ascomycota, and Chytridiomycota were the dominant bacteria in the plateau and low-altitude regions. Significant differences between the dominant microorganisms in the rumen of yaks were evident in the two regions. The proportion of fiber-degrading bacteria was significantly different between yaks dwelling at high-altitude and low-altitude regions. The abundance of starch-degrading bacteria was not significantly different with altitude. Species clustering similarity analysis showed that the rumen microorganisms in the two areas were obviously isolated and clustered into branches. Functional prediction showed significant differences in rumen microbial methane metabolism, starch and sucrose metabolism, ion-coupled transporter and bacterial secretion system at different altitudes. Overall, the results of this study improved our understanding of the abundance and composition of microorganisms in the rumen of yak at different altitudes.

Host and altitude factors affect rumen bacteria in cattle.

There are many kinds of microorganisms in the gastrointestinal tract of mammals, some of which are closely related to the host. Rumen microorganisms are essential for normal physiological activities of their host by decomposing plant crude lignin and providing essential nutrients. The composition and diversity of this microbial population are influenced by the host, environment, and diet. Despite its importance, little is known about the effects of factors such as altitude variation on rumen microbial population abundance and diversity in different ruminants. Here, we described the changes in overall rumen bacteria in four groups of cattle, including the Zhongdian yellow cattle and Zhongdian yaks, grazing at high altitudes (3600 m); the Jiangcheng yellow cattle and Jiangcheng buffalo were kept at an altitude of 1100 m. We found that there was a significant difference in rumen bacterial abundance of the Zhongdian yellow cattle and Zhongdian yaks at high altitude and there was obvious homogeneity in rumen bacterial abundance and diversity in the Jiangcheng yellow cattle and Jiangcheng buffalo at low altitude. Therefore, our research concluded that under the same dietary environment, there were differences in the abundance and diversity of certain bacteria in the rumen of different breeds of cattle, indicating that host genetic factors and intestinal microorganisms related to altitudinal variation had a greater influence on rumen bacterial abundance in the cattle.

Directed modification of a ruminal cellulase gene (CMC-1) from a metagenomic library isolated from Yunnan gayal (Bos frontalis).

Gayal (Bos frontalis) of the Yunnan region is well adapted to harsh environmental conditions. Its diet consists predominantly of bamboo, reeds, and woody plants, suggesting that the rumen of this species contains many fiber-degrading bacteria and cellulases. The aim of this study was to identify and modify specific cellulases found in the gayal rumen. In the present study, a directed evolution strategy of error-prone PCR was employed to improve the activity or optimal temperature of a cellulase gene (CMC-1) isolated from gayal rumen. The CMC-1 gene was heterologously expressed in Escherichia coli (E. coli) BL21, and the recombinant CMC-1 protein hydrolyzed carboxyl methyl cellulose (CMC) with an optimal activity at pH 5.0 and 50 °C. A library of mutated ruminal CMC-1 genes was constructed and a mutant EP-15 gene was identified. Sequencing analysis revealed that EP-15 and CMC-1 belonged to the glycosyl hydrolase family 5 (GHF5) and had the highest homology to a cellulase (Accession No. WP_083429257.1) from Prevotellaceae bacterium, HUN156. There were similar predicted GH5 domains in EP-15 and CMC-1. The EP-15 gene was heterologously expressed and exhibited cellulase activity in E. coli BL21 at pH 5.0, but the optimum temperature for its activity was reduced from that of CMC-1 (50 °C) to 45 °C, which was closer to the physiological temperature of the rumen (40 °C). The cellulase activity of EP-15 was about two times higher than CMC-1 at 45 °C or PH 5.0, and also was more stable in response to temperature and pH changes compared to CMC-1. This study successfully isolated and modified a ruminal cellulase gene from metagenomics library of Yunnan gayal. Our findings may obtain a useful cellulase in future applications and present the first evidence of modified cellulases in the gayal rumen.

[Effectiveness of total elbow arthroplasty with preservation of triceps brachii insertion approach].

OBJECTIVE: To investigate the effectiveness of total elbow arthroplasty (TEA) with preservation of triceps brachii insertion approach. METHODS: Between January 2012 and September 2017, 17 patients with elbow disease were treated with TEA with preservation of triceps brachii insertion approach. There were 3 males and 14 females, with an average age of 65.2 years (range, 48-85 years). The injuries located on left elbow in 5 cases and on right elbow in 12 cases. There were 11 cases of distal humerus fracture (AO type C1 in 2 cases and type C3 in 9 cases); the interval between fracture and operation was 3-10 days (mean, 4.1 days). There were 3 cases of osteoarthritis and 3 cases of rheumatoid arthritis, with the disease duration of 2-26 years (mean, 8.7 years). The postoperative elbow function and pain was assessed by Mayo elbow performance score (MEPS) and visual analogue scale (VAS) score, respectively. The prosthesis position, heterotopic ossification, and periprosthetic fracture were observed by X-ray films. RESULTS: All incisions healed by first intention. Sixteen patients were followed up 18-69 months (mean, 40.6 months). Intraoperative ulnar nerve injury occurred in 2 cases, and healed after symptomatic treatment. At last follow-up, the MEPS score was 55-100 (mean, 90.3). The results were excellent in 11 cases, good in 2 cases, fair in 2 cases, and poor in 1 case, with an excellent and good rate of 81.3%. The VAS score was 0-2 (mean, 0.4). X-ray reexamination showed that no polyethylene wear, prosthesis loosening and fracture, abnormal prosthesis position, periprosthetic fracture occurred during the follow-up period, and the prosthesis survival rate was 100%. Heterotopic ossification occurred in 2 and 3 months after operation in 2 cases, respectively. CONCLUSION: The triceps on approach for TEA are satisfactory for distal humerus fracture, osteoarthritis, and rheumatoid arthritis.

Gill transcriptome alterations in Macrobrachium rosenbergii under copper exposure.

Copper is one of common contaminants in estuaries and coastal zones, which may cause physiological dysfunction in aquatic organisms. However, molecular response triggered by Cu have remained largely unknown in freshwater prawn Macrobrachium rosenbergii. In the present study, we performed transcriptomic analysis to characterize molecular mechanisms of copper immunotoxicity in gills from M. rosenbergii. A large number of potential simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs) loci in the transcriptome were identified. 19,417 and 8989 differentially expressed genes (DEGs) were obtained at 3 h and 48 h after exposure, respectively. Most of these DEGs were down-regulated implying that gene expressions were largely inhibited by Cu, which might lead to impairments of biological functions. Functional enrichment analysis of these DEGs revealed that immune, detoxification and apoptosis were the differentially regulated processes by Cu stress. 12 DGEs involved in immune response and heavy metal detoxification were discovered and validated by qRT-PCR. The results indicated that the M. rosenbergii might counteract the toxicity of Cu at the transcriptomic level by increasing expressions of immune- and heavy metal detoxification-related genes, and these selected genes could be used as molecular indicators for Cu stress. Our study firstly reported the stress response at transcriptional level in M. rosenbergii during Cu exposure. The genes and pathways identified here not only give us new insight into molecular mechanisms underlying Cu toxicity effects in prawn, but facilitate biomarker identification and stress-resistant breeding studies.

Natural selection on TMPRSS6 associated with the blunted erythropoiesis and improved blood viscosity in Tibetan pigs.

Tibetan pigs, indigenous to Tibetan plateau, are well adapted to hypoxia. So far, there have been not any definitively described genes and functional sites responsible for hypoxia adaptation for the Tibetan pig. The whole genome-wide association studies in human suggested that genetic variations in TMPRSS6 was associated with hemoglobin concentration (HGB) and red cell counts (RBC). Here we conducted resequencing of the nearly entire genomic region (40.1 kb) of the candidate gene TMPRSS6 in 40 domestic pigs and 40 wild boars along continuous altitudes and identified 708 SNPs, in addition to an indel (CGTG/----) in the intron 10. We conduct the CGTG indel in 838 domestic pigs, both the CGTG deletion frequency and the pairwise r2 linkage disequilibrium showed an increase with elevated altitudes, suggesting that TMPRSS6 has been under Darwinian positive selection. As the conserved core sequence of hypoxia-response elements (HREs), the deletion of CGTG in Tibetan pigs decreased the expression levels of TMPRSS6 mRNA and protein in the liver revealed by real-time quantitative PCR and western blot, respectively. We compared domestic pigs and Tibetan pigs living continuous altitudes, found that the blood-related traits with the increase of altitude, however, the HGB did not increase with the elevation in Tibetan pigs. Genotype association analysis results dissected a genetic effect on reducing HGB by 13.25 g/L in Gongbo'gyamda Tibetan pigs, decreasing mean corpuscular volume (MCV) by 4.79 fl in Diqing Tibetan pigs. In conclusion, the CGTG deletion of TMPRSS6 resulted in lower HGB and smaller MCV, which could reflect a blunting erythropoiesis and improving blood viscosity as well as erythrocyte deformability. It remains to be determined whether a blunting of erythropoiesis for TMPRSS6 or others genetic effects are the physiological adaptations among Tibetan pigs.

Alginate capped and manganese doped ZnS quantum dots as a phosphorescent probe for time-resolved detection of copper(II).

A method is described for the detection of Cu(II). It is based on the use of a room-temperature phosphorescent probe consisting of alginate-capped and manganese(II)-doped ZnS quantum dots. The carboxy groups at the surface of the probe strongly coordinate Cu(II) to form a complex. As a result, the 4T1-6A1 transition of the Mn(II) ions in the probe is quenched, and the long decay time (~2.1 ms in the unquenched state) is accordingly reduced. At excitation/emission wavelengths of 316/590 nm and a delay time of 0.1 ms, the probe shows a linear response in the 0.01 to 12 µM Cu(II) concentration range. The detection limit is 6.0 nM and the RSD is 3.2% (for n = 5). Graphical Abstract A two-step procedure is described to synthesize alginate capped manganese doped ZnS QDs. These coordinate with Cu(II) to form an absorbent complex and can be used as a phosphorescent probe for time-resolved detection of Cu(II).