Pangenome and multi-tissue gene atlas provide new insights into the domestication and highland adaptation of yaks

Background The genetic diversity of yak,a key domestic animal on the Qinghai-Tibetan Plateau(QTP),is a vital resource for domestication and breeding efforts.This study presents the first yak pangenome obtained through the de novo assembly of 16 yak genomes.Results We discovered 290 Mb of nonreference sequences and 504 new genes.Our pangenome-wide presence and absence variation(PAV)analysis revealed 5,120 PAV-related genes,highlighting a wide range of variety-specific genes and genes with varying frequencies across yak populations.Principal component analysis(PCA)based on binary gene PAV data classified yaks into three new groups:wild,domestic,and Jinchuan.Moreover,we pro-posed a‘two-haplotype genomic hybridization model'for understanding the hybridization patterns among breeds by integrating gene frequency,heterozygosity,and gene PAV data.A gene PAV-GWAS identified a novel gene(Bos-Gru3G009179)that may be associated with the multirib trait in Jinchuan yaks.Furthermore,an integrated transcrip-tome and pangenome analysis highlighted the significant differences in the expression of core genes and the muta-tional burden of differentially expressed genes between yaks from high and low altitudes.Transcriptome analysis across multiple species revealed that yaks have the most unique differentially expressed m RNAs and lnc RNAs(between high-and low-altitude regions),especially in the heart and lungs,when comparing high-and low-altitude adaptations.Conclusions The yak pangenome offers a comprehensive resource and new insights for functional genomic studies,supporting future biological research and breeding strategies.

Study on the Correlation between Blood Enzyme Activity and Production Performance in Tibetan Yaks

Yak ( Bos grunniens ) is classified as Bovine genus,they live in Qingzang Plateau with elevation more than 3500m and it's neighbor highland,where the weather is high chilly,short of oxygen and large difference of temperature between day and night.But yak have adapted that circumstance after thousands of years' artificial and natural selection and has great anti adversity capacity.Yak is an important sustenance and means of production to Tibetan.China is a country with the largest number of yak,whose amount of livestock on hand accounts for 95% of the world and Tibet region takes the second place next to Qinghai in the number of yak.Tibetan yak has formed some groups for Tibetan's large area,complicated geological ecosystem conditions,geological isolation.The typical better groups are Yadong yak,Jiali yak and Sibu yak. Study about yak fell behind other animals due to the restriction of inconvenient transportation,difficult sampling and poor experimental technology.Study about the relationship between yak blood enzyme activities and milk production was little,only Jing (1992) studied correlation of milk production with serum amylase,esterase in Gansu Jiulong yak,Maiwa yak and no report was found in other groups.This study discussed six Jiali yak blood enzyme activities lactate dehydrogenase (LDH),alkaline phosphatases (AKP),acid phosphatase (ACP),catalase (CAT),amylase (Amy) and superoxide dismutase (SOD),and explored their relationship with milk production in Jiali yak,so as to supply with theoretical evidence by using blood enzyme activity as biochemical assisted selection marker in the breeding of Tibetan yak milk yield. This experiment investigated activity of six blood enzymes from 28 Tibetan yaks and explored its relationship to production performance.The results showed a extremely positive significant difference ( P <0.01) between activity of LDH and milk yield,CAT activity and length of belly hair respectively,while a positive significant difference ( P <0.05) was observed between AKP activity and body weight,Amy activity and body weight and a negative significant difference ( P <0.05) for SOD activity and body weight.Stepwise Regression Analysis showed that activity of LDH could be used for the prediction of milk yield,AKP,CAT,Amy for body weight,CAT,Amy for length of belly hair.So it is expected to use activity of LDH,AKP,CAT,Amy as biochemical genetic marker in the selection of milk yield,body weight and length of belly hair.

Potential antibacterial activity of berberine against multi drug resistant enterovirulent Escherichia coli isolated from yaks(Poephagus grunniens) with haemorrhagic diarrhoea

Objective:To evaluate the antimicrobial efficacy of berberine,a plant alkaloid.Methods:Five multi-drug resistant（MDR） STEC/EPEC and five MDR ETEC isolates from yaks with haemorrhagic diarrhoea were selected for the study.Antibacterial activity of berberine was evaluated by broth dilution and disc diffusion methods.The binding kinetics of berberine to DNA and protein was also enumerated.Results:For both categories of enterovirulent Escherichia coli（E.roli） isolates, berberine displayed the antibaclerial effect in a dose dependent manner.The MIC50 of berberine chloride for STEC/EPEC isolates varied from 2.07μM to 3.6μM with a mean of（2.95±0.33）μM where as for ETEC strains it varied from 1.75 to 1.96μM with a mean of（1.87±0.03）μM. Berberine bind more tightly with double helix DNA with Bmax and Kd of（24.68±2.62） and（357.8±57.8）,respectively.Berberine reacted with protein in comparatively loose manner with Bmax and Kd of（18.9±3.83） and 【286.2±113.6),respectively.Conclusions:The results indicate clearly that berberine may serve as a good antibacterial against multi drug resistant E.coli.

Comparison of rumen archaeal diversity in adult and elderly yaks(Bos grunniens)using 16S rRNA gene high-throughput sequencing

This study was conducted to investigate the phylogenetic diversity of archaea in the rumen of adult and elderly yaks. Six domesticated female yaks, 3 adult yaks （（5.3±0.6） years old）, and 3 elderly yaks （（10.7±0.6） years old）, were used for the rumen contents collection. Illumina MiSeq high-throughput sequencing technology was applied to examine the archaeal composition of rumen contents. A total of 92 901 high-quality archaeal sequences were analyzed, and these were assigned to 2 033 operational taxonomic units （OTUs）. Among these, 974 OTUs were unique to adult yaks while 846 OTUs were unique to elderly yaks; 213 OTUs were shared by both groups. At the phylum level, more than 99% of the obtained OTUs belonged to the Euryarchaeota phylum. At the genus level, the archaea could be divided into 7 archaeal genera. The 7 genera （i.e., Methanobrevibacter, Methanobacterium, Methanosphaera, Thermogymnomonas, Methanomicrobiu, Meth- animicrococcus and the unclassified genus） were shared by all yaks, and their total abundance accounted for 99% of the rumen archaea. The most abundant archaea in elderly and adult yaks were Methanobrevibacterand Thermogymnomonas, respectively. The abundance of Methanobacteria （class）, Methanobacteriales （order）, Methanobacteriaceae （family）, and Methanobrevibacter （genus） in elderly yaks was significantly higher than in adult yaks. In contrast, the abundance of Ther-mogymnomonas in elderly yaks was 34% lower than in adult yaks, though the difference was not statistically significant. The difference in abundance of other archaea was not significant between the two groups. These results suggested that the structure of archaea in the rumen of yaks changed with age. This is the first study to compare the phytogenetic differences of rumen archaeal structure and composition using the yak model.

Effect of Nitrogenous Fertilizer Treatment on Mineral Metabolism in Grazing Yaks

To assess the impact of N fertilization on contents of mineral elements in herbage and the effect of increased forage S on the copper metabolism of grazing yaks, study was conducted during the summer grazing season （2005, 2006, and 2007）. Pasture replicates （20 ha; n=3 per treatment） received the same fertilizer treatment in each growing season, consisting of i） 90 kg N ha^-1 from quickly available nitrogen, ii） 90 kg N ha^-1 from ammonium nitrate, iii） 90 kg N ha^-1 from ammonium sulfate, and iv） control （no fertilizer）. Forage sampling was collected at 60 days intervals following fertilization （10 samples per pasture） for Cu, Mo, Mn, Se, Fe, Zn, Ca, and P. To determine the effect of fertilizer treatment on mineral metabolism in grazing yaks, liver and blood samples were collected at the start and end of the study period in 2005, 2006, and 2007. Ammonium sulfate fertilization increased （P 〈 0.01） forage S concentration. Plant tissue N concentrations were increased by N fertilization, regardless of source in 2005, 2006, and 2007. Yaks grazing S fertilization pastures had lower （P〈0.05） liver and blood Cu concentrations at the end of the study period in 2005, 2006, and 2007, compared with urea, ammonium nitrate, and control. Nominal increases in forage in vitro organic matter digestibility were realized by fertilization, regardless of N source in each year.

Sulfur-Induced Copper Deficiency in the Yaks

Since the 1990s, yak in the Haizi area in China has been affected by an ailment characterized by pica, emaciation, dyskinesia, and anemia. To determine the cause of disease, the mineral composition of soil and forages, and samples of blood, hair, and liver of yaks from the Haizi area in China were determined. The concentrations of copper in soil and forage from affected ranches and unaffected areas are within the normal ranges. The mean concentration of copper in blood and liver from the affected yaks was （0.31±0.03） and （13.7±3.1）μg·g^-1 respectively, compared with （0.98±0.16） and （95.6±11.2）μg·g^-1 for unaffected yaks. The concentrations of sulfur in soil and forage from affected ranches were （1.91±0.26） and （1.37±0.17）%, respectively, compared with （1.11±0.31） and （0.52±0.18）% （dry matter） for normal areas. The contents of sulfur in blood and liver affected animals were （7.32±1.8） and （2.54±3.1）%, respectively, compared with （4.22±0.73） and （1.31±0.33）% （in fresh and soft tissues） for healthy animals, respectively. Oral administration of tribasic copper chloride prevented and cured the disease. Thus it is reasonable to conclude that ailments of yaks in the Haizi area are probably caused by a secondary copper deficiency, mainly due to high sulfur content in soil and forage.

Morphological Observation on the Test and Epididymis in Hybrid of Wild and Domestic Yaks During the Growth Periods

This paper was carried out on the morphological character of the test and epididymis of three types of yak bull age 6,12,18,24 months old (1/2 wild yak, cross 1/2 wild yak and domestic yak). The results showed that the weight and size of testes and epidiymis was increased with the age which was hardly affected by imbalance of food supply during the cold and warm seasons. The development were similar for three kinds of yak at the same age(P＞0.05).

Confinement and Semi-confinement Raising Fattening Technology of Yaks in Agricultural Areas of Tibet

In the study, confinement and semi-confinement raising fattening technology of yaks in agricultural areas of tibet were analyzed. And several suggestions for improving the efficiency of yak raising were put forward. Aiming at providing the reference of healthy raising and sustainable development of yaks in the agricul- tural areas of tibet.

Supplementation with yak (Bos grunniens) bone collagen hydrolysate altered the structure of gut microbiota and elevated short-chain fatty acid production in mice

In this study, yak bone collagen hydrolysate(YBCH)was produced by mixed proteases and provided to standard-diet mice at a different dose(low dose(LD), medium dose(MD), and high dose(HD))to investigate its effects on the composition of gut microbiota and short-chain fatty acids(SCFA)production. It was found that YBCH was mainly composed of small molecular peptides whose molecular weight below 2 000 Da. Notably, supplementation with different doses of YBCH could significantly downregulate the ratio of Firmicutes to Bacteroidetes in the fecal microbiota. At the family level, the Lachnospiraceae abundance was significantly reduced in the YBCH gavage groups(mean reduction ratio 41.7 %, 35.2%, and 36.4% for LD, MD, and HD group, respectively). The predicted functions of gut microbes in the MD group were significantly increased at “lipid metabolism” and “glycan biosynthesis and metabolism”. Moreover, the SCFA production in the YBCH groups was elevated. Especially, the concentration of acetic acid, propionic acid, and butyric acid in the MD group was separately increased 79.7%, 89.2%, and 78.8% than that in the NC group. These results indicated that YBCH might be applied in the development of functional food for intestinal microecological regulation.

Meat Production from Crossbred and Domestic Yaks in China

Female domesticated yaks were artificially inseminated with semen taken from wild yaks and the offspring used to form a nucleus breeding herd of crossbred animals. The meat production of the first generation(F1 × F2)from breedtng within the nucleus herd was assessed by slaughter and carcass dissection of males. One group(no. =14)was slaughtered at 6 months of age and the second(no. = 12)at 18months. Crossbred yaks were significantly heavier(P＜0.01)at 6 months(74.7(s. e. 10.41)kg v. 59.8(s.e. 10.23)kg)and at 18 months(150.5(s. e. 56.1)kg v. 117.7(s. e. 17.4)kg)than domesticated ones,The killing-out proportion(0.47)was similar at both ages and for both groups of animals. Carcass weight,meat weight and the yield of prime cuts were higher for crossbred animals than for domestic yak at both ages.

The Milking Performance of dual-purpose Crossbred Yaks

Wild yak males were crossed with domesticated female yaks to produce a breeding herd of crossbred animals. The milk production of the progeny of this herd was measured in the present study. Yaks were milked once daily after prior suckling of the calf. yaks were allowed to graze for 15 h/day on high-altitude(3200 to 3500 m) pastures. No supplementary food was given. Average daily milk yield of 1.77(s. e. 0. 16)kg and milk yield over 120 days,212.2(s. e. 20.2)kg were significantly higher(P＜0.01)than the corresponding figures for uninlproved domestic yaks(1.53(s. e. 0. 10)kg and 164. 6(s. e. 10.5)kg respectively). The fat content of milk from crossbred yaks, 52(s. e. 2. 9)g/kg, was not significantly dlfferent from that of unimproved animals, 53.5(s. e. 4. 1), g/kg.

Domestication process of yaks revealed

In his monumental work “Origin of Species,” Charles Darwin suggested that all domestic animals originated from their wild an-

Improving the Breed of Yaks

Yaks live in high frigid areas some 3,000-5,000 meters above sea level.In China there are 13 million yaks,making up 90 percent of the world total.They provide with transport means,meat and hide for 4.6 Tibe-tans in Tibet as well as Qinghai,Sichuan,Yunnan and Gansu prov-inces.

基于转录组数据挖掘牦牛皱胃发育代谢的关键候选基因

旨在比较不同年龄段牦牛皱胃指数测定、转录组表达谱的变化,挖掘影响牦牛皱胃发育代谢的信号通路和关键基因,为进一步探讨牦牛皱胃发育机制提供理论基础。本研究对1日龄、20日龄、60日龄、15月龄与3岁的牦牛皱胃组织进行转录组测序,对转录组数据进行质控、比对、差异表达基因筛选,并对差异表达基因进行GO功能注释和KEGG富集分析。为进一步验证测序数据的可靠性,随机选取5个差异表达基因进行qRT-PCR验证。结果显示,在发育过程中,瘤胃重的增长最快,其次是瓣胃、网胃和皱胃。转录组结果显示,以1日龄组为对照,在20日龄、60日龄、15月龄和3岁组中分别鉴定到1310、1715、1931和2199个差异表达基因,4个组共有基因565个;以前一个时间点为对照,20日龄、60日龄、15月龄和3岁组分别鉴定到1310、861、569和597个差异表达基因,4个对比组共有基因9个。GO功能注释发现,以1日龄组为对照,20日龄、60日龄、15月龄和3岁组分别富集到1191、2578、1117和2835条显著条目,不同年龄组的前10条显著性GO条目中有共有的,也有各年龄阶段特有的条目。KEGG富集分析结果显示,20日龄、60日龄、15月龄和3岁4个年龄段的前30条显著通路中特有信号通路分别为4、1、3和4条,包括ECM受体相互作用、细胞色素P450对外源性物质的代谢和药物代谢-细胞色素P450等与皱胃发育相关的通路。qRT-PCR结果与测序结果基本一致,表明测序结果可靠。通过对牦牛不同发育阶段皱胃组织的转录组测序及生物信息学分析,筛选到与皱胃发育相关的差异表达候选基因,这些基因主要参与胃粘膜上皮细胞增殖分化、细胞分化和免疫调控等过程,其中GKN1、CXCL17、SCNN 1B、SCNN 1G、CCL 5和IGF 2BP3等基因可能在牦牛皱胃发育过程中起着重要作用;进一步筛选到参与皱胃葡萄糖代谢、葡萄糖转运、脂肪酸转运、肽转运等过程相关的信号通路和候选基因,其中GANAB、GBA2、SLC 2A1、SLC 2A3、SLC 2A4、CPT 1B、SLC 15A1等是与牦牛皱胃组织营养代谢和吸收相关的重要候选基因。

YAKS710-4 6300kW 6kV高压增安型三相异步电动机的研制

介绍了YAKS71 0 - 4 630 0kW 6kV高压增安型三相异步电动机的研制过程、性能指标及防爆安全性等 ,对该电动机的技术经济性进行了分析 ,并提出了非防爆型避雷器、电容器在防爆危险区域内应用所采取的措施。

犊牦牛肾周棕色脂肪组织的发育及其产热相关基因的表达分析

棕色脂肪组织(BAT)作为非震颤性产热(NST)的主要产热器官,在新生动物的寒冷适应中发挥重要的作用。为探究犊牦牛肾周BAT的发育及其产热相关基因的表达,本试验采集1日龄、7日龄和30日龄犊牦牛肾周脂肪组织,利用苏木精-伊红染色观察脂肪细胞,利用透射电子显微镜观察脂滴和线粒体的超微结构,利用免疫组织化学染色、实时荧光定量PCR和蛋白质免疫印迹(Western blot)检测解偶联蛋白1(UCP1)在脂肪细胞的定位、mRNA和蛋白表达水平,以及脂肪转化因子过氧化物酶体增殖激活受体α(PPARα)和过氧化物酶体增殖物受体γ共激活因子1α(PGC-1α)基因mRNA表达水平。结果显示,犊牦牛肾周存在2种类型的脂肪细胞,即含有小脂滴和大量线粒体的棕色脂肪细胞以及含有大脂滴和少量线粒体的白色脂肪细胞;与1日龄犊牦牛相比,7日龄和30日龄犊牦牛肾周白色脂肪细胞的面积和密度均显著增加(P<0.05),棕色脂肪细胞的面积和密度均显著降低(P<0.05);不同日龄犊牦牛肾周棕色脂肪细胞和白色脂肪细胞质膜上均有UCP1阳性表达,与1日龄犊牦牛相比,7日龄和30日龄犊牦牛肾周脂肪细胞中UCP1阳性表达强度均显著降低(P<0.05);与1日龄犊牦牛相比,30日龄犊牦牛肾周脂肪组织中BAT产热相关基因(UCP1、PPARα和PGC-1α)mRNA表达水平均显著降低(P<0.05);与1日龄犊牦牛相比,7日龄和30日龄犊牦牛肾周脂肪组织中UCP1蛋白表达水平均显著降低(P<0.05)。结果表明,出生后犊牦牛肾周棕色脂肪细胞数量逐渐减少而白色脂肪细胞数量逐渐增加,且产热相关基因表达水平逐渐降低。该结果为深入探究犊牦牛寒冷适应机制提供了参考资料。

四川、西藏部分地区牦牛场球虫感染情况调查

【目的】调查四川省和西藏自治区部分地区牦牛球虫感染情况,为该地区牦牛球虫病的预防、控制提供理论参考。【方法】从四川省和西藏自治区部分地区8个牦牛场采集2~6、7~12和>12月龄牦牛的新鲜粪样共376份,采用饱和盐水漂浮法对粪便样品中球虫卵囊进行定性检查,采用麦克马斯特计数法统计球虫阳性粪样中每克粪便中的球虫卵囊数(OPG),了解不同牦牛场、不同月龄牦牛的球虫感染情况。【结果】8个牦牛场均检测出球虫感染,阳性样品共85份,平均感染率为22.6%(85/376),平均OPG为1643。共检出9种艾美耳属球虫,优势虫种为阿拉巴艾美耳球虫,感染率为37.6%(32/85),多呈混合感染。平均感染率最高的是2~6月龄牦牛,感染率为37.9%(11/29);其次是7~12月龄牦牛,感染率为31%(57/184);>12月龄牦牛的球虫感染率为10.4%(17/163)。【结论】四川和西藏部分地区牦牛场均存在不同程度的球虫感染,均以混合感染为主。牦牛球虫感染率、感染强度以及优势虫种在不同地区、不同年龄牦牛之间存在差异。

帕米尔牦牛屠宰性能及肉品质分析

为揭示帕米尔牦牛种质资源特性,选取成年公母牛各5头进行屠宰性能及肉品质测定,并与文献报道的查吾拉牦牛、环湖牦牛、大通牦牛、肃南牦牛、金川牦牛、九龙牦牛数据进行比较分析。结果显示,帕米尔牦牛公牛的活重(317.00 kg)、胴体重(164.16 kg)、眼肌面积(45.85 cm^(2))、屠宰率(51.32%)和净肉率(39.56%)比母牛分别高25.79%、29.60%、11.45%、2.23%和0.18%,母牛的肉骨比(4.48)比公牛高12.10%。与其他牦牛品种相比,帕米尔牦牛公牛的活重和胴体重比大通牦牛分别高3.31%和43.01%,比环湖牦牛分别高39.04%和61.10%;屠宰率比大通牦牛、环湖牦牛和查乌拉牦牛分别高13.49%、14.89%和6.01%;净肉率比大通牦牛和环湖牦牛分别高31.38%和15.13%,肉骨比比环湖牦牛高7.53%。帕米尔牦牛公牛肉的熟肉率(62.38%)、pH0值(5.86)、pH24值(5.46)和嫩度(10.04 kgf)比母牦牛分别高1.33%、1.21%、3.80%和9.61%,但母牛肉色的亮度(9.97)、红度(37.14)和黄度(10.73)比公牛分别高23.24%、4.44%和2.68%。帕米尔牦牛公牛肉的氨基酸总量(21.09 g/100 g)比大通牦牛和金川牦牛分别高13.39%和2.08%。帕米尔牦牛公、母牛肉的EAA/TAA均大于38.5%,EAA/NEAA分别为63.87%和63.19%。说明帕米尔牦牛肉不仅氨基酸总量丰富,而且必需氨基酸和非必需氨基酸比例适宜。可见,帕米尔牦牛具有良好的屠宰性能及优良的肉品质和营养价值,在今后的品种选育和育肥过程中应该更加重视优质肉块的产量、肉品质及营养价值的整体提升。

青海地区不同动物源志贺菌毒力相关基因的分布研究

为了解青海省不同动物源志贺菌相关毒力基因的分布情况,试验对分离自青海省不同地区的62株不同动物源志贺菌进行了DNA提取,将其作为模板对志贺菌的毒力基因set1B、virA、set1A、ial、ipaBCD、Sen、icsP、iutA、icsA、ipaH进行了PCR检测,并统计各毒力基因在不同动物源志贺菌中的检出率、不同动物源志贺菌毒力基因携带模式及携带毒力基因种类。结果表明:62株志贺菌毒力基因set1B、virA、set1A、ial、ipaBCD、icsP、Sen、iutA、icsA、ipaH的检出率分别为6.5%、43.5%、3.2%、25.8%、37.1%、0、12.9%、22.6%、50.0%、100%。在27株猪源志贺菌中,毒力基因ipaH、VirA、icsA、ipaBCD的检出率较高,然后依次为ial、iutA、Sen,未检出icsP。在27株鸡源志贺菌中,毒力基因ipaH、icsA、virA的检出率较高,然后依次为ipaBCD、ial、Sen、iutA,未检出set1B、set1A、icsP。在4株牦牛源志贺菌中,毒力基因ipaH、icsA、ipaBCD的检出率较高,然后依次为virA、ial、iutA,未检出set1B、set1A、Sen、icsP。在4株藏羊源志贺菌中,毒力基因ipaH、ipaBCD、iutA的检出率较高;然后依次为virA、ial,未检出set1B、set1A、Sen、icsP、icsA。在62株志贺菌中,有7株菌只检出毒力基因ipaH,55株菌携带两种及以上毒力基因,共呈现出30种携带模式,其中以virA-icsA-ipaH模式的菌株最多(11.3%,7/62),然后为ipaBCD-ipaH模式(9.7%,6/62);猪源和鸡源志贺菌毒力基因的携带模式均为18种,牦牛和藏羊源志贺菌毒力基因的携带模式均为4种。在62株志贺菌中,有18株菌携带2种毒力基因,15株菌携带3种毒力基因,13株菌携带4种毒力基因,7株菌携带5种毒力基因,2株菌携带6种毒力基因。27株猪源志贺菌中携带1,2,3,4,5,6种毒力基因菌株的占比分别为3.7%、40.7%、14.8%、18.5%、14.8%、7.4%,27株鸡源志贺菌中携带1,2,3,4,5,6种毒力基因菌株的占比分别为18.5%、18.5%、29.6%、22.2%、11.1%、0,4株牦牛源志贺菌中携带1,2,3,4,5,6种毒力基因菌株的占比分别为25.0%、0、25.0%、50.0%、0、0,4株藏羊源志贺菌中携带1,2,3,4,5,6种毒力基因菌株的占比分别为0、50.0%、50.0%、0、0、0。62株志贺菌单毒力基因携带率(11.3%,7/62)<多重毒力基因携带率(88.7%,55/62),其中猪源志贺菌的多重基因携带率最高(42.0%),然后依次为鸡源(35.5%)、藏羊源(6.4%)和牦牛源(4.8%)。说明青海地区志贺菌携带多种毒力基因,携带模式呈现多样性且因动物源不同有所差异,同时应重点加强青海地区猪志贺菌病的防治工作。

LPA对牦牛卵丘细胞扩张因子HAS2、PTGS2和PTX3表达的影响

本研究以溶血磷脂酸(lysophosphatidic acid,LPA)在卵丘细胞扩张中的作用为切入点,旨在探讨不同浓度LPA对牦牛卵丘细胞(yak cumulus cells,YCCs)中卵丘扩张因子(透明质酸合成酶2(hyaluronate synthase 2,HAS2)、前列腺素内过氧化物合酶2(prostaglandin-endoperoxide synthase 2,PTGS2)和正五聚蛋白3(pentraxin 3,PTX3))表达的影响。本研究以健康成年(3~4岁)雌牦牛的YCCs为研究对象,取对数生长期的YCCs,将不同浓度的LPA(空白对照、阴性对照、5、15、30和50μmol·L^(-1))作用于体外培养的YCCs,分别培养12、24、36、48 h后,CCK-8检测YCCs的细胞活性,采用RT-qPCR和Western-blot法检测YCCs中HAS2、PTGS2和PTX3 mRNA和蛋白相对表达量,细胞免疫荧光染色法检测卵丘扩张因子HAS2、PTGS2和PTX3在YCCs中的分布。试验中每个处理组3个重复。结果显示,LPA孵育12、24、36和48 h,对YCCs的活性有着明显的促进作用。当孵育时间为24 h时,LPA对YCCs活性的促进作用最明显。相比较于对照组而言,当LPA浓度为15μmol·L^(-1)时,不同孵育时间中YCCs的活性提升最为显著(P<0.05)。当LPA浓度为15μmol·L^(-1)时,与空白对照组相比,HAS2、PTGS2和PTX3的mRNA和蛋白相对表达量最高(P<0.05),且YCCs中HAS2、PTGS2和PTX3的荧光强度明显增强。当LPA浓度大于15μmol·L^(-1)时,HAS2、PTGS2和PTX3的mRNA和蛋白相对表达量逐渐下降。本研究表明,LPA对YCCs活性具有促进作用。当孵育时间为24 h,并且LPA浓度为15μmol·L^(-1)时,活性提升最为显著(P<0.05)。LPA可以增强YCCs中卵丘扩张因子HAS2、PTGS2、PTX3的表达,且其作用浓度具有剂量依赖性,最佳浓度为15μmol·L^(-1)。研究结果为阐明LPA促进牦牛卵丘细胞扩张的分子机制提供了理论依据,为进一步提高牦牛卵母细胞的质量和体外受精(in vitro fertilization,IVF)成功率提供理论基础。