Bos Grunniens Research Articles

C-type natriuretic peptide treatment before in vitro maturation enhances maturation of yak oocytes and developmental competence of their crossbred embryos

ABSTRACT The effects of C-type natriuretic peptide (CNP) pre-treatment on the in vitro maturation (IVM) and developmental competence of yak (Bos grunniens) oocytes were evaluated. The results showed that 100 nM CNP could effectively maintain meiotic arrest of yak oocytes in vitro within 6 h. Yak oocytes matured in two-step IVM (pre-IVM with 100 nM CNP for 6 h followed by conventional IVM for 28 h) yielded a significantly (P < .05) increased cleavage rate, blastocyst rate after in vitro fertilization with cattle spermatozoa compared to the conventional one-step IVM method. The density of transzonal projections (TZPs) decreased after 6 h standard IVM (P < .05), whereas, COCs pre-IVM with 100 nM CNP for 6 h maintained the same density of TZPs compared to the fresh COCs. This pre-IVM resulted in lesser reactive oxygen species level (P < .05). Two-step IVM resulted in the increased glutathione levels, mRNA expression levels of BCL2, BMP15, and GDF9 (P < .05) in oocytes. In conclusion, these results indicate that CNP treatment (100 nM, 6 h) before IVM could enhance the maturation of yak oocytes and developmental competence of their crossbred embryos. This may have important applications in in vitro production of yak crossbred embryos.

Identification and postnatal developmental characteristics of brown adipose tissue in yak calves

AbstractBackgroundBrown adipose tissue (BAT) provides newborn mammals with a critical capacity for non‐shivering thermogenesis and enables their adaptation to the cold of the extrauterine environment. The domestic yak (Bos grunniens) has evolved on the Qinghai–Tibet Plateau and has adapted well to extremely cold and hypoxic environments. However, the location, characterization and postnatal development of BAT in yak calves remain largely unknown.MethodsWe identified different types of adipocytes and explored the postnatal development of interscapular and subcutaneous adipose tissue in yak calves at 1, 7 and 30 days old using morphological and molecular biology methods.ResultsThe results show that multilocular and unilocular adipocytes were found in two depots. Multilocular adipocytes contained small lipid droplets packed with numerous mitochondria. However, unilocular adipocytes contained a single unilocular lipid droplet and few mitochondria. The number of multilocular adipocytes significantly decreased, whereas the number of unilocular adipocytes significantly increased from day 1 to 30. Furthermore, uncoupling protein 1 (UCP1) expressions in both multilocular and unilocular adipocytes, as well as UCP1 mRNA and protein expression, were significantly decreased from day 1 to 30. In addition, peroxisome proliferator‐activated receptor‐γ coactivator‐1α and peroxisome proliferator‐activated receptor alpha mRNA expression were significantly decreased.ConclusionsThe results of the research indicate that adipocytes in both newborn yak calf interscapular and subcutaneous adipose tissue are multilocular adipocytes. Many multilocular adipocytes were transformed into unilocular adipocytes after birth, but some multilocular adipocytes remained at day 30; this transition occurred at different rates in different depots. These results provide a basis for further study of BAT in yak calves.

Isolation and Screening of Cellulolytic Bacteria from Yak (Bos grunniens) Excreta from Lahaul Valley Region for Pre-treatment of Paddy Straw in Himachal Pradesh

The present study was conducted during August, 2021 at Department of Agricultural Engineering, College of Agriculture, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur to isolate and identify the cellulolytic bacteria from yak dung, yak dung manure and soil samples from spiti region in Lahaul-Spiti district of Himachal Pradesh. The bacterial isolates were identified by using morphological and biochemical standard methods, and identification based on Bergey’s Manual of Determinative Bacteriology. Cellulolytic bacteria from mentioned samples were isolated and cultured on CMC (Carboxymethyl cellulose) agar medium. The activity of cellulolytic bacterial was conducted based on halo area and cellulolytic index on CMC agar medium. Among 24 isolates of bacteria, 08 isolates were identified as cellulolytic bacteria. Furthermore, our isolates with higher cellulolytic index were identified as the Bacillus and Pseudomonas genus. Out of eight efficient cellulolytic isolates were identified as Bacillus spp. (06) three from yak dung manure, two from yak dung and one from soil sample and Pseudomonas spp. (02) one from yak dung manure and one from soil sample. Most Efficient cellulose degrading isolates of Bacillus spp. and Pseudomonas spp. were employed for biological pretreatment of paddy straw for two weeks and then run in laboratory biogas digester along with control digester. These digester sets were under observation from the second day of run upto three weeks and it was observed that the there was 10% hike in biogas production as compare to control digester on 22nd days at laboratory condition.

Proteomic Analysis Reveals the Effects of Different Dietary Protein Levels on Growth and Development of Jersey-Yak

Jersey-yak is a hybrid offspring of Jersey cattle and yak (Bos grunniens). Changing the feeding system of Jersey-yak can significantly improve its growth performance. In this study, tandem mass tag (TMT) proteomics technology was used to determine the differentially expressed proteins (DEPs) of the longissimus lumborum (LL) muscle of Jersey-yak fed different protein levels of diet. The results showed that compared with the traditional grazing feeding, the growth performance of Jersey-yaks was significantly improved by crude protein supplementation after grazing. A total of 3368 proteins were detected in these muscle samples, of which 3365 were quantified. A total of 434 DEPs were identified. Through analyses, it was found that some pathways related to muscle growth and development were significantly enriched, such as Rap1 signaling pathway, mTOR signaling pathway, and TGF-beta signaling pathway. A number of DEPs enriched in these pathways are related to muscle cell development, differentiation, and muscle development, including integrin subunit alpha 7 (ITGA7), myosin heavy chain 8 (MYH8), and collagen type XII alpha 1 chain (COL12A1). In conclusion, the results of this study provide insights into the proteomics of different feeding patterns of Jersey-yak, providing a stronger basis for further understanding the biological mechanism of hybrid varieties.

Whole-genome resequencing of major populations revealed domestication-related genes in yaks

BackgroundThe yak is a symbol of the Qinghai-Tibet Plateau and provides important basic resources for human life on the plateau. Domestic yaks have been subjected to strong artificial selection and environmental pressures over the long-term. Understanding the molecular mechanisms of phenotypic differences in yak populations can reveal key functional genes involved in the domestication process and improve genetic breeding.Material and methodHere, we re-sequenced 80 yaks (Maiwa, Yushu, and Huanhu populations) to identify single-nucleotide polymorphisms (SNPs) as genetic variants. After filtering and quality control, remaining SNPs were kept to identify the genome-wide regions of selective sweeps associated with domestic traits. The four methods (π, XPEHH, iHS, and XP-nSL) were used to detect the population genetic separation.ResultsBy comparing the differences in the population stratification, linkage disequilibrium decay rate, and characteristic selective sweep signals, we identified 203 putative selective regions of domestic traits, 45 of which were mapped to 27 known genes. They were clustered into 4 major GO biological process terms. All known genes were associated with seven major domestication traits, such as dwarfism (ANKRD28), milk (HECW1, HECW2, and OSBPL2), meat (SPATA5 and GRHL2), fertility (BTBD11 and ARFIP1), adaptation (NCKAP5, ANTXR1, LAMA5, OSBPL2, AOC2, and RYR2), growth (GRHL2, GRID2, SMARCAL1, and EPHB2), and the immune system (INPP5D and ADCYAP1R1).ConclusionsWe provided there is an obvious genetic different among domestic progress in these three yak populations. Our findings improve the understanding of the major genetic switches and domestic processes among yak populations.

Whole genome resequencing-based analysis of plateau adaptation in Meiren yak (Bos grunniens)

The Meiren yak is an important genetic resource in Gansu Province, China. In this study, we aimed to explore the evolutionary history and population structure of the genetic resource of Meiren yak and to mine the characteristic genes of Meiren yak. We analysed a total of 93 yaks of eight yak breeds based on whole genome resequencing combined with population genomics and used θπ ratio and Fst method to screen the selected sites in the genome region. The results proved that Meiren yak can be used as a potential genetic resource in Gansu Province. The genes in Meiren yak with positive selection in selection signal analysis were subjected to the Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses, which indicated that the genes were related to the adaptability to high altitude and hypoxic environment. By analysing the genetic variation of Meiren yak at the genome-wide level, this study provided a theoretical basis for genetic improvement of Meiren yak and for the development of high-quality yak resources.

Multi-omics revealed the effects of dietary energy levels on the rumen microbiota and metabolites in yaks under house-feeding conditions.

Yak (Bos grunniens) is a unique large ruminant species in the Qinghai-Tibetan Plateau (QTP). Changing the energy levels of their rations can significantly improve their growth performance. Therefore, studying the effects of dietary energy levels on the rumen microflora and metabolites of yak is crucial for enhancing the development of the yak industry. Currently, there is a lack of understanding regarding the impact of feeding energy diets on rumen fermentation parameters, microbial functions, and metabolites. This study was designed to determine the appropriate energy level for feeding yak. Three test diets with metabolizable energy levels of 7.57 MJ/kg, 9.44 MJ/kg, and 11.9 MJ/kg were used and the concentration of volatile fatty acids (VFA) in rumen fluid was measured. The microbial communities, functions, and metabolites in yaks were studied by 16S rRNA sequencing, metagenome, and LC-MS non-targeted metabolomics to investigate the relationships among rumen fermentation parameters, microbial diversity, and metabolites. Ration energy levels significantly affect total VFA, acetate, propionate, butyrate, iso-valerate, valerate, and acetate/propionate (p < 0.05). At the phylum level, the dominant phyla in all three treatment groups were Bacteroidota, Firmicutes, and Actinobacteriota. At the genus level, the abundance of the unclassified_o__Bacteroidales, norank_f_Muribaculaceae, Lachnospiraceae_NK4A136_group, and Family _XIII_AD3011_group showed significant differences (p < 0.05) and were significantly correlated with differential metabolites screened for phosphatidylcholine [PC(16:0/0:0), PC(18:3/0:0)], uridine 3'-monophosphate, and adenosine monophosphate, etc. CAZymes family analysis showed that GHs and CEs differed significantly among the three groups. In addition, differential metabolites were mainly enriched in the pathways of lipid metabolism, nucleotide metabolism, and biosynthesis of other secondary metabolites, and the concentrations of differential metabolites were correlated with microbial abundance. In summary, this study analyzed the effects of ration energy levels on rumen microorganisms and metabolites of yaks and their relationships. The results provided a scientific basis for the selection of dietary energy for yaks in the house feeding period in the future.

MRNA-Seq of testis and liver tissues reveals a testis-specific gene and alternative splicing associated with hybrid male sterility in dzo.

Alternative splicing (AS) plays an important role in the co-transcription and post-transcriptional regulation of gene expression during mammalian spermatogenesis. The dzo is the male F1 offspring of an interspecific hybrid between a domestic bull (Bos taurus ♂) and a yak (Bos grunniens ♀) which exhibits male sterility. This study aimed to identify the testis-specific genes and AS associated with hybrid male sterility in dzo. The iDEP90 program and rMATS software were used to identify the differentially expressed genes (DEG) and differential alternative splicing genes (DSG) based on RNA-seq data from the liver (n = 9) and testis (n = 6) tissues of domestic cattle, yak, and dzo. Splicing factors (SF) were obtained from the AmiGO2 and the NCBI databases, and Pearson correlation analysis was performed on the differentially expressed SFs and DSGs. We focused on the testis-specific DEGs and DSGs between dzo and cattle and yak. Among the top 3,000 genes with the most significant variations between these 15 samples, a large number of genes showed testis-specific expression involved with spermatogenesis. Cluster analysis showed that the expression levels of these testis-specific genes were dysregulated during mitosis with a burst downregulation during the pachynema spermatocyte stage. The occurrence of AS events in the testis was about 2.5 fold greater than in the liver, with exon skipping being the major AS event (81.89% to 82.73%). A total of 74 DSGs were specifically expressed in the testis and were significantly enriched during meiosis I, synapsis, and in the piRNA biosynthesis pathways. Notably, STAG3 and DDX4 were of the exon skipping type, and DMC1 was a mutually exclusive exon. A total of 36 SFs were significantly different in dzo testis, compared with cattle and yak. DDX4, SUGP1, and EFTUD2 were potential SFs leading to abnormal AS of testis-specific genes in dzo. These results show that AS of testis-specific genes can affect synapsis and the piRNA biosynthetic processes in dzo, which may be important factors associated with hybrid male sterility in dzo.

Whole-genome resequencing reveals the uniqueness of Subei yak.

Subei yak is an essential local yak in the Gansu Province, which genetic resource has recently been discovered. It is a meat-milk dual-purpose variety with high fecundity and relatively stable population genetic structure. However, its population genetic structure and genetic diversity are yet to be reported. Therefore, this study aimed to identify molecular markers of Subei yak genome by whole-genome resequencing, and to analyze the population structure and genetic diversity of Subei yak. This study screened 12,079,496 single nucleotide polymorphism (SNP) molecular markers in the 20 Subei yaks genome using whole-genome resequencing technology. Of these SNPs, 32.09% were located in the intronic region of the genome. Principal component analysis, phylogenetic analysis, and population structure analysis revealed that the Subei yak belonged to an independent group in the domestic yak population. A selective clearance analysis was carried out on Subei yak and other domestic yaks, and the genes under positive selection were annotated. The functional enrichment analysis showed that Subei yak possessed prominent selection characteristics in terms of external environment perception, hypoxia adaptation, and muscle development. Furthermore, Subei yak showed excellent muscle fat deposition and meat quality traits. Thus, this study will serve as a reference for discovering population structure, genetic evolution, and other unique traits of Subei yak and for expanding the genetic variation catalog of yaks.

Dynamic changes in cellular atlases and communication patterns within yak ovaries across diverse reproductive states unveiled by single-cell analysis.

Yaks (Bos grunniens) exhibit exceptional adaptation to the challenging high-altitude environment of the Qinghai-Tibetan plateau, making them the sole bovine species capable of thriving in such exreme conditions. Investigating the cellular and molecular characteristics of yak ovaries across different reproductive states is crucial for gaining insight into their ovarian functions. Herein, the cellular atlases of yak ovaries in different reproductive states were depicted by single-cell RNA-sequencing (scRNA-seq). The cellular atlases of the ovaries were established by identifying specific gene expression patterns of various cell types, including granulosa cells, theca cells, stromal cells, smooth muscle cells, endothelial cells, glial cell, macrophages, natural killer cells, and proliferating cells. The cellular compositions of the ovaries vary among different reproductive states. Furthermore, the granulosa cells comprise six cell subtypes, while theca cells consist of eight cell subtypes. The granulosa cells and theca cells exhibit distinct biological functions throughout different reproductive states. The two cell types were aligned along their respective pseudotime trajectories. Moreover, a cell-to-cell communication network was constructed among distinct cell types within the ovary, spanning the three reproductive states. Notably, during the estrus period, the granulosa cells demonstrated more prominent interactions with other cell types compared to the remaining reproductive states.

Influence of environmental factors on physiological state of domestic yak (Bos mutus) (on the example of the Steppe Research Station “Orenburg Tarpania”)

Increased interest in the treatment and prevention of diseases of large herbivorous animals is associated with the processes of their acclimatisation during introduction and reintroduction, modelling behaviour in the conditions of existence in a wild natural environment, with minimal human participation. Since 2014, acclimatisation of domestic yak (Bos mutus Przewalski, 1883) in the steppe zone in the east of the Russian Plain, at the Steppe Research Station “Orenburg Tarpania” has been carried out. “Orenburg Tarpania” is a project of the Steppe Institute of the Ural Branch of the Russian Academy of Sciences to return large ungulates to their natural habitat in order to maintain optimal functioning of natural ecosystems. The ideology of the project corresponds to the concept of ecological rewilding. The animals are kept in a semi-voluntary state. The domestic yak is chosen as a species adapted to existence in extreme conditions with low temperature, extreme solar radiation in the southern latitudes, and relatively arid conditions. The conditions of yak keeping in the steppe zone differ from its natural habitat. During the period of observation, two reasons for the disturbance of the physical condition of animals have been recorded. Firstly, these are injuries received in the process of life activity. Injuries are often complicated by wolfarthiasis. The second disturbance of physical condition of domestic yak is eye damage in some individuals, which occurs due to incomplete adaptation of some animals to high wind activity, typical for the steppe region. The main cause of conjunctivitis and keratitis is dust raised by strong winds. A set of measures has been developed and adapted to provide treatment of animals in conditions close to natural habitat and semivoluntary confinement.

Evidence for early domestic yak, taurine cattle, and their hybrids on the Tibetan Plateau

Domestic yak, cattle, and their hybrids are fundamental to herder survival at high altitudes on the Tibetan Plateau. However, little is known about their history. Bos remains are uncommon in this region, and ancient domestic yak have not been securely identified. To identify Bos taxa and investigate their initial management, we conducted zooarchaeological analyses of 193 Bos specimens and sequenced five nuclear genomes from recently excavated assemblages at Bangga. Morphological data indicated that more cattle than yak were present. Ancient mitochondrial DNA and nuclear genome sequences identified taurine cattle and provided evidence for domestic yak and yak-cattle hybridization ~2500 years ago. Reliance on diverse Bos species and their hybrid has increased cattle adaptation and herder resilience to plateau conditions. Ancient cattle and yak at Bangga were closely related to contemporary livestock, indicating early herder legacies and the continuity of cattle and yak husbandry on the Tibetan Plateau.

Differential metabolites screening in yak (Bos grunniens) seminal plasma after cryopreservation and the evaluation of the effect of galactose on post-thaw sperm motility

Sperm survival and activity depend on the provision of energy and nutrients from seminal plasma (SP). This study aimed to investigate the variations of metabolites within SP before and after freezing and subsequently explore the potential regulatory mechanisms affecting yak sperm cryodamage due to changes in metabolites in the SP. Untargeted metabolomics analysis was performed to screen for differential metabolites, followed by KEGG analysis to identify enriched signaling pathways. The combinatorial analysis of metabolomics and sperm proteomics revealed the influence of key SP metabolites on sperm proteins. Subsequently, the relevant differentially expressed proteins were verified by Western blot analysis. Finally, the mechanism underlying the positive effect of galactose on sperm motility was determined by assessing the change in ATP content in sperm before and after freezing and thawing. The data showed that a total of 425 and 269 metabolites were identified in the positive and negative ion modes, respectively. Freezing and thawing resulted in the up-regulation of 70 metabolites and the down-regulation of 29 metabolites in SP. The primary impact of freezing and thawing was observed in carbohydrate metabolism, including pyruvate metabolism, pentose phosphate pathway, galactose metabolism, the TCA cycle, and butanoate metabolism. In the combined analysis and Western blot results, a significant positive correlation was observed between galactose and Aldo-keto reductase family 1 member B1 (AKR1B1) (P < 0.05), which has the ability to convert galactose into galactol. Furthermore, the addition of galactose to thawed semen improved sperm motility by increasing AKR1B1 protein in sperm and was associated with the content of ATP. These data identify differential metabolites between fresh and frozen-thawed SP and suggest that galactose is a valuable additive for cryopreserved sperm, providing a theoretical basis for further exploration of the refrigerant formula for yak sperm cryopreservation.

Polymorphisms of CCSER1 Gene and Their Correlation with Milk Quality Traits in Gannan Yak (Bos grunniens).

Coiled-coil serine-rich protein 1 (CCSER 1) gene is a regulatory protein gene. This gene has been reported to be associated with various economic traits in large mammals in recent years. The aim of this study was to investigate the association between CCSER1 gene single nucleotide polymorphisms (SNPs) and Gannan yaks and to identify potential molecular marker loci for breeding milk quality in Gannan yaks. We genotyped 172 Gannan yaks using Illumina Yak cGPS 7K liquid microarrays and analyzed the correlation between the three SNPs loci of the CCSER1 gene and the milk qualities of Gannan yaks, including milk fat, protein and casein. It was found that mutations at the g.183,843A>G, g.222,717C>G and g.388,723G>T loci all affected the fat, protein, casein and lactose traits of Gannan yak milk to varying extents, and that the milk quality of individuals with mutant phenotypes was significantly improved. Among them, the milk fat content of AG heterozygous genotype population at g.183,843A>G locus was significantly higher than that of AA and GG genotype populations (p < 0.05); the casein and protein content of mutant GG and CG genotype populations at g.222,717C>G locus was significantly higher than that of wild-type CC genotype population (p < 0.05); and the g.388,723G>T locus of the casein and protein contents of the mutant TT genotype population were significantly higher (p < 0.05) than those of the wild-type GG genotype population. These results provide potential molecular marker sites for Gannan yak breeding.

Molecular Cloning and Functional Characterization of the 5′ Regulatory Region of the SLC11A1 Gene from Yaks

The solute transport protein family 11 A1 (SLC11A1), also recognized as natural resistance-associated macrophage protein 1 (NRAMP1), represents a transmembrane protein encoded by the SLC11A1 gene. A variety of prior investigations have illuminated its involvement in conferring resistance or susceptibility to bacterial agents, positioning it as a promising candidate gene for breeding disease-resistant animals. Yaks (Bos grunniens), renowned inhabitants of the Qinghai-Tibet Plateau in China, stand as robust ruminants distinguished by their adaptability and formidable disease resistance. Notwithstanding these unique traits, there is scant literature on the SLC11A1 gene in the yak population. Our inquiry commences with the cloning of the 5′ regulatory region sequence of the Zhongdian yak SLC11A1 gene. We employ bioinformatics tools to identify transcription factor binding sites, delineating pivotal elements like enhancers and cis-acting elements. To ascertain the promoter activity of this region, we amplify four distinct promoter fragments within the 5′ regulatory region of the yak SLC11A1 gene. Subsequently, we design a luciferase reporter gene vector containing four site-specific deletion mutations and perform transient transfection experiments. Through these experiments, we measure and compare the activity of disparate gene fragments located within the 5′ regulatory region, revealing regions bearing promoter functionality and discerning key regulatory elements. Our findings validate the promoter functionality of the 5′ regulatory region, offering preliminary insights into the core and principal regulatory segments of this promoter. Notably, we identified single nucleotide polymorphisms (SNPs) that may be associated with important regulatory elements such as NF-1 and NF-1/L. This study provides a theoretical framework for in-depth research on the function and expression regulation mechanism of the yak SLC11A1 gene.

Lumpy Skin Disease (LSD) in Yak (Bos grunniens): An Evidence of Species Spillover from Cattle in India.

Lumpy skin disease (LSD), caused by the lumpy skin disease virus (LSDV), is a global concern that affects cattle and buffalo. Recently, the disease has been reported in new species such as the Indian Gazelle, Camel, Banteng, Gaur, and Giraffe from various parts of the world. This report provides an insight into the occurrence of LSD in Yak from Sikkim, a North-Eastern state of India. During the investigation, both cattle and yak exhibited typical clinical signs of LSD, including skin nodular lesions. The morbidity, mortality, and case fatality rates for cattle were 9.08%, 1.84%, and 20.24%, respectively. Similarly, the morbidity, mortality, and case fatality rates in yak were 7.57%, 1.24%, and 16.33%, respectively. The virus isolation and amplification of LSDV-specific genes confirmed the presence of LSDV in cattle, yak, and vectors. Further, demonstrated antibodies in randomly collected sera from naïve and unvaccinated cattle and yak using indirect Enzyme Linked Immuno-sorbent Assay (iELISA) and Serum Neutralisation test (SNT) from this region. Sequencing and phylogenetic analysis of P32, GPCR, and RPO30 genes revealed that the virus isolated from both species was 100% identical to each other and also closely related to the field LSDV isolates circulating in the Indian subcontinent. The study highlighted the emergence of LSDV in unconventional hosts and underscored the need to include other bovine species in national disease control programs, encompassing disease surveillance initiatives.

Histological characteristics of hair follicles at different hair cycle and in vitro modeling of hair follicle-associated cells of yak (Bos grunniens).

To adapt to the extreme conditions of plateau environments, yaks have evolved thick hair, making them an ideal model for investigating the mechanisms involved in hair growth. We can gain valuable insights into how hair follicles develop and their cyclic growth in challenging environments by studying yaks. However, the lack of essential data on yak hair follicle histology and the absence of in vitro cell models for hair follicles serve as a limitation to such research objectives. In this study, we investigated the structure of skin tissue during different hair follicle cycles using the yak model. Additionally, we successfully established in vitro models of hair follicle-associated cells derived from yak skin, including dermal papilla cells (DPCs), preadipocytes, and fibroblasts. We optimized the microdissection technique for DPCs culture by simplifying the procedure and reducing the time required. Furthermore, we improved the methodology used to differentiate yak preadipocytes into mature adipocytes, thus increasing the differentiation efficiency. The introduction of yak as a natural model provides valuable research resources for exploring the mechanisms of hair growth and contributes to a deeper understanding of hair follicle biology and the development of regenerative medicine strategies.

Prevalence and Genetic Characterization of Morphologically Indistinguishable Sarcocysts of Sarcocystis cruzi in Cattle and Sarcocystis poephagicanis in Yaks

Sarcocystis cruzi in cattle (Bos taurus) and Sarcocystis poephagicanis in yaks (Bos grunniens) are morphologically indistinguishable. However, the relationship between the two parasites is still unclear. Here, muscular tissues of the two species of domestic animal collected from abattoirs in China were examined for sarcocysts of S. cruzi and S. poephagicanis. The sarcocysts isolated from the samples were analyzed using light microscopy (LM), transmission electron microscopy (TEM), and DNA analysis. Sarcocysts of S. cruzi and S. poephagicanis were found in 405 of 950 (42.6%) cattle and 304 of 320 (95.0%) yaks. LM and TEM showed that the sarcocysts of the two parasites had similar morphological characteristics. The thin-walled sarcocysts had hair-like protrusions on the surface. The ultrastructures were demonstrated to include a primary cyst wall containing irregularly folded, hirsute, or bone-like protrusions. Four genetic markers of the two parasites were sequenced and analyzed, namely, 18S rDNA, 28S rDNA, mitochondrial cox1, and apicoplast rpl6. The sequences of the four loci had an interspecific similarity of 97.9–98.6%, 97.2–98.1%, 89.5–90.4%, and 96.9–97.2% identity, respectively. Phylogenetic analysis using 28S rDNA and cox1 sequences indicated that both S. cruzi and S. poephagicanis were placed into a group encompassing Sarcocystis spp. in ruminants with canid as known or putative definitive hosts. Sarcocystis cruzi and S. poephagicanis represent separate species, and cox1 and rpl6 were suitable for distinguishing between them.

Study of Transcriptomic Analysis of Yak (Bos grunniens) and Cattle (Bos taurus) Pulmonary Artery Smooth Muscle Cells under Oxygen Concentration Gradients and Differences in Their Lung Histology and Expression of Pyruvate Dehydrogenase Kinase 1-Related Factors.

The aim of this study was to investigate the molecular mechanisms by which hypoxia affects the biological behavior of yak PASMCs, the changes in the histological structure of yak and cattle lungs, and the relationships and regulatory roles that exist regarding the differences in the distribution and expression of PDK1 and its hypoxia-associated factors screened for their role in the adaptation of yak lungs to the plateau hypoxic environment. The results showed that, at the level of transcriptome sequencing, the molecular regulatory mechanisms of the HIF-1 signaling pathway, glucose metabolism pathway, and related factors (HK2/PGK1/ENO1/ENO3/ALDOC/ALDOA) may be closely related to the adaptation of yaks to the hypoxic environment of the plateau; at the tissue level, the presence of filled alveoli and semi-filled alveoli, thicker alveolar septa and basement membranes, a large number of erythrocytes, capillary distribution, and collagen fibers accounted for all levels of fine bronchioles in the lungs of yaks as compared to cattle. A higher percentage of goblet cells was found in the fine bronchioles of yaks, and PDK1, HIF-1α, and VEGF were predominantly distributed and expressed in the monolayers of ciliated columnar epithelium in the branches of the terminal fine bronchioles of yak and cattle lungs, with a small amount of it distributed in the alveolar septa; at the molecular level, the differences in PDK1 mRNA relative expression in the lungs of adult yaks and cattle were not significant (p > 0.05), the differences in HIF-1α and VEGF mRNA relative expression were significant (p < 0.05), and the expression of PDK1 and HIF-1α proteins in adult yaks was stronger than that in adult cattle. PDK1 and HIF-1α proteins were more strongly expressed in adult yaks than in adult cattle, and the difference was highly significant (p < 0.01); the relative expression of VEGF proteins was not significantly different between adult yaks and cattle (p > 0.05). The possible regulatory relationship between the above results and the adaptation of yak lungs to the plateau hypoxic environment paves the way for the regulatory mechanisms of PDK1, HIF-1α, and VEGF, and provides basic information for studying the mechanism of hypoxic adaptation of yaks in the plateau. At the same time, it provides a reference for human hypoxia adaptation and a target for the prevention and treatment of plateau diseases in humans and plateau animals.

Study of relations between chemical, colour and fluorescence properties of raw and dried meat powders of cow and yak (Bos grunniens)

Gluteus medius, Longissimus thoracis, and Semitendinosus muscles from the cow and yak (Bos grunniens) reared in the Kyrgyz Republic were dried by convective (hot air) drying and freeze drying. The dried muscles were grinded into fine powders and along with raw muscles were evaluated for water activity (aW), chemical composition (moisture, fat, protein), colour characteristics (L, a, and b values), fluorescence of intrinsic fluorophores (tryptophan, vitamin A, and riboflavin). Processing of measured data tables using common components and specific weights analysis (CCSWA) showed close relations among the chemical, colour, and fluorescence data. CCSWA discriminated muscles depending on chemical composition, animal type, and drying technique applied based on the chemical properties, colour characteristics, and fluorescence spectra. The freeze drying was approved as a preferable dehydration technique comparing with convective drying as the one causing less discoloration to meat. Partial Least Squares Regression (PLSR) models developed using fluorescence spectra allowed accurate quantitative predicting of water activity (aW), moisture, fat, and protein contents, and colour characteristics (L, a, and b values).