RNA-Seq analysis reveals the potential molecular mechanisms of daidzein on adipogenesis in subcutaneous adipose tissue of finishing Xianan beef cattle

Daidzein has been reported to be effective in regulating lipid metabolism in animals. However, the molecular mechanisms of daidzein on adipogenesis in beef cattle are not yet reported and the results of daidzein on affecting lipid metabolism in other species have been conflicting. High-throughput sequencing of mRNA (RNA-Seq) technology was performed to elucidate the underlying molecular mechanisms of daidzein on adipogenesis in subcutaneous adipose tissue of finishing Xianan beef cattle. A total of 893 differentially expressed genes (DEGs) were identified by differential expression analysis, among which 405 genes were upregulated and 488 genes were downregulated. Bioinformatics analysis suggested that these DEGs were significantly enriched to the pathways related to lipid metabolism including ECM–receptor interaction, Glycolysis/Gluconeogenesis and Hedgehog signalling pathway. Daidzein significantly affected the candidate genes (Shh, Pec, Gli, Wnt6, DLK, IGFBP2, ID3 and C/EBPE) related to adipocyte differentiation. Besides, daidzein improved the ability of subcutaneous adipocytes in synthesizing triglycerides by directly using the long-chain fatty acids and enhanced the efficiency of triglyceride synthesis of subcutaneous adipocytes in Xianan steers. In conclusion, daidzein plays a positive role not only in adipogenic differentiation, but also in triglyceride synthesis in subcutaneous adipose tissue of Xianan beef cattle.     

Moringa oleifera leaf flavonoids protect bovine mammary epithelial cells from hydrogen peroxide-induced oxidative stress in vitro

Bovine mammary epithelial cells (BMECs) of high-producing dairy cows are subject to constant oxidative stress as a result of high metabolic rate and physiological adaptation to intensive farming. Moringa (Moringa oleifera) leaf has been proposed to have the antioxidant potential in scavenging free radicals due to the presence of flavonoids. In this study, we investigated the cytoprotective effects of moringa leaf flavonoids in alleviating oxidative stress in BMECs in vitro. Oxidative stress was established by exposing isolated BMECs to H₂O₂ for 2 hr. Doses of moringa leaf flavonoids were evaluated by treating BMECs for 12 hr. The optimal concentrations of H₂O₂ and moringa leaf flavonoids were 500 μmol/L and 1.0 mg/ml, respectively. The results showed that moringa leaf flavonoids increased the activities of superoxide dismutase, catalase, and glutathione peroxidase; and reduced malondialdehyde activity and intracellular accumulation of reactive oxygen species (ROS) in the H₂O₂-induced oxidative stress system. A Hoechst33258 staining assay revealed that moringa leaf flavonoids decreased the apoptosis rate in BMECs, while leaving membrane integrity and nucleolar morphology unchanged. We concluded that moringa leaf flavonoids have the antioxidant capacity to effectively reduce oxidative stress in BMECs.     

Identification of Differentially Expressed Genes and Lipid Metabolism Signaling Pathways between Muscle and Fat Tissues in Broiler Chickens

In this study, signaling pathways and key differentially expressed genes (DEGs) involved in lipid metabolism in muscle and fat tissues were investigated. Muscle and abdominal fat tissues were obtained from 35-day-old female broilers for RNA sequencing. DEGs between muscle and fat tissues were identified. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of DEGs were performed. A total of 6130 DEGs were identified to be significantly enriched in 365 GO terms, most of which were involved in biological processes, cellular components, and molecular functions in muscle and fat tissues. Three important lipid signaling pathways (pyruvate metabolism, the insulin signaling pathway, and the adipocytokine signaling pathway) were identified among the fat and muscle tissues of broilers. The key common DEGs in these pathways included phosphoenolpyruvate carboxykinase 2 (PCK2), acetyl-CoA carboxylase 1 alpha and beta (ACACA and ACACB), and the mitogen-activated protein kinase (AMPK) gene family. Hence, our findings revealed the pathways and key genes and gene families involved in the regulation of fat deposition in the muscle and fat tissues of broilers.     

PCR-based detection of genes encoding virulence determinants in Staphylococcus aureus from bovine subclinical mastitis cases

The present study was carried out to genotypically characterize Staphylococcus aureus (S. aureus) isolated from bovine mastitis cases. A total of 37 strains of S. aureus were isolated during processing of 552 milk samples from 140 cows. The S. aureus strains were characterized phenotypically, and were further characterized genotypically by polymerase chain reaction using oligonucleotide primers that amplified genes encoding coagulase (coa), clumping factor (clfA), thermonuclease (nuc), enterotoxin A (entA), and the gene segments encoding the immunoglobulin G binding region and the X region of protein A gene spa. All of the isolates yielded an amplicon with a size of approximately 1,042 bp of the clfA gene. The amplification of the polymorphic spa gene segment encoding the immunoglobulin G binding region was observed in 34 isolates and X-region binding was detected in 26 isolates. Amplification of the coa gene yielded three different products in 20, 10, and 7 isolates. The amplification of the thermonuclease gene, nuc, was observed in 36 out of 37 isolates. All of the samples were negative for the entA gene. The phenotypic and genotypic findings of the present strategies might provide an understanding of the distribution of the prevalent S. aureus clones among bovine mastitis isolates, and might aid in the development of steps to control S. aureus infections in dairy herds.     

Occurrence and Characterization of Escherichia coli O157 Isolated from Cattle in Norway

Faecal samples from 504 imported beef cattle were screened to investigate the occurrence of Escherichia coli O157. The results were compared with those from a previous screening of Norwegian dairy cattle, and the occurrence was found to be higher in the imported beef cattle. The E. coli O157 isolates from the previous and present studies were characterized for the genes encoding for shigatoxin 1 (stx ₁), shigatoxin 2 (stx ₂), the intimin protein (eae) and the flagellar protein H7 (fliC) using PCR analysis, pulsed-field gel electrophoresis (PFGE) with the restriction enzyme XbaI, and bacteriophage lambda RFLP analysis using the PvuII restriction enzyme. The isolates from the dairy and beef cattle could be distinguished by the profiles of the toxin genes and by PFGE patterns. Whether the importation of animals in itself should be regarded as a risk factor for the occurrence of E. coli O157, or whether other management factors contribute to the differences in carrier rates compared to the previous study on domestic cattle, is discussed.     

转录组测序筛选山羊妊娠早期胚胎附植相关基因

旨在通过胚胎附植前、后的山羊子宫角组织高通量测序筛选妊娠早期胚胎附植的关键基因。本研究选取2～4岁体重相近((44.76±3.49)kg)的经产努比亚母山羊16只，在同期发情-人工输精配种后的第15(D15)和第30天(D30)分别随机选取3只羊颈动脉放血处死。采集子宫角组织利用Illumina HiSeq进行高通量转录组测序(RNA-Seq)，筛选差异表达基因(differentially expressed genes, DEGs)并对DEGs进行功能注释，基因功能查询进一步筛选与胚胎附植直接相关的调控基因，荧光定量PCR(qRT-PCR)对筛选的基因进行表达量验证分析。D15和D30子宫角组织转录本比较分析发现了 2 000个DEGs，其中上调基因620个，下调基因1 380个。GO功能聚类分析共分为3大类52组，其中细胞组分17组，生物过程23组，分子功能12组，获得细胞连接与增殖，生物粘附与调节，分子活性与转导等重要生物途径。以D15表达量高低为排序标准，从表达量最高的10个基因中筛选出了与胚胎附植有关的基因MGP和TAGLN；从上调和下调幅度最大的前10个差异表达基因中，获得参与妊娠相关糖蛋白合成与分泌的基因PAG-3、PAG-8、PAG-12，参与生长因子结合与生长激素释放激素受体活性相关基因GHRHR和胰岛素样生长因子结合蛋白基因IGFBP1。qRT-PCR结果显示，随机选取的6个基因在D15和D30子宫角中表达变化趋势与RNA-Seq结果一致。获得的基因MGP、TAGLN、PAG-3、PAG-8、PAG-12、GHRHR、IGFBP1在努比亚山羊胚胎附植中具有重要作用。     

Study on Effect of IGF-1 on Proliferation and Apoptosis of Bovine Mammary Epithelial Cells by Adding Inhibitor

The test was aimed to study the effect of insulin-like growth factor 1(IGF-1) on the proliferation of bovine mammary epithelial cells (BMECs),and provide a theoretical basis for the subsequent regulating mammary gland development using IGF-1. The optimal IGF-1 concentration for inhibiting BMECs apoptosis was obtained by measuring the apoptosis rate at 12, 24, 48 and 72 h after the addition of IGF-1 at four groups (0, 10, 50 and 100 μg/mL). Then divided into six groups:BMECs group, BMECs+IGF-1 group, BMECs+LY294002 group, BMECs+IGF-1+LY294002 group, BMECs+RAPA group and BMECs+IGF-1+RAPA group,and the apoptosis rates were detected by flow cytometry. The results showed that the heterologous IGF-1 had an inhibitory effect on the apoptosis of BMECs with an optimal concentration of 50 μg/mL. The apoptosis rates of BMECs+IGF-1+LY294002 and BMECs+IGF-1+RAPA groups were extremely significantly higher than BMECs+IGF-1 group (P<0.01). This study suggested that IGF-1 could activate the PI3K/Akt/mTOR signaling pathway and thereby inhibit the apoptosis of BMECs. Moreover, IGF-1 might also promote the "repair" mechanism for the inhibited PI3K/Akt/mTOR signaling pathway, and therefore make it reparticipate in BMECs life process.     

添加通路阻断剂对IGF-1影响奶牛乳腺上皮细胞增殖与凋亡的研究

试验旨在研究胰岛素样生长因子-1（insulin-like growth factor 1,IGF-1）对奶牛乳腺上皮细胞（bovine mammary epithelial cells,BMECs）增殖的影响,为后期利用IGF-1调控乳腺发育奠定理论基础。以奶牛乳腺上皮细胞为材料,首先分4组分别外源添加0（对照组）、10、50、100 μg/mL IGF-1且分别培养12、24、48、72 h,测定抑制BMECs凋亡率的最佳浓度;然后分6组：单纯BMECs组、BMECs+IGF-1组、BMECs+LY294002组、BMECs+IGF-1+LY294002组、BMECs+RAPA组和BMECs+IGF-1+RAPA组,采用流式细胞术测定各组细胞凋亡率。结果表明,外源性添加IGF-1对BMECs凋亡率具有抑制作用,最佳浓度为50 μg/mL;BMECs+IGF-1+LY294002与BMECs+IGF-1+RAPA组细胞凋亡率均极显著高于BMECs+IGF-1组（P<0.01）。推断IGF-1能够活化PI3K/Akt/mTOR信号通路,参与BMECs凋亡的调控作用,进而抑制BMECs细胞凋亡;IGF-1可能会对被抑制PI3K/Akt/mTOR信号通路产生"修复"机制,使其能够重新参与BMECs的生命进程。     

基于转录组测序挖掘奶牛乳脂代谢关键候选基因

旨在对高、低乳脂率奶牛乳腺上皮细胞(BMECs)转录组测序的mRNA表达谱数据进行深入分析,挖掘影响奶牛乳脂代谢的关键候选基因。本研究采用Illumina PE150方法对乳脂率具有极端差异的荷斯坦奶牛(高、低乳脂组各4头)的BMECs进行转录组测序,以P<0.05和|log₂FoldChange|≥1.5为阈值筛选差异表达基因,并利用KOBAS在线网址进行功能富集分析,最后通过实时荧光定量PCR(qRT-PCR)技术分析测序结果的准确性及乳脂代谢相关差异表达基因的组织表达谱。结果表明,在高、低乳脂组之间共发现578个差异表达基因,包括332个上调差异表达基因,246个下调差异表达基因。功能富集分析共确定了包含生物学过程(BP)、细胞组分(CC)和分子功能(MF)的366个显著富集的GO条目(P<0.05),其中与脂代谢密切相关的GO条目有长链脂肪酸的运输、脂肪细胞分化的正向调节、乳腺肺泡发育、花生四烯酸的结合等。差异表达基因显著富集到47条KEGG通路(P<0.05),参与脂代谢的通路有15条,分别为脂肪细胞内脂解的调节、磷脂酶D信号通路、河马...     

Methicillin‐Resistant Staphylococcus aureus from Brazilian Dairy Farms and Identification of Novel Sequence Types

The aim of this study was to investigate the phenotypic and genotypic diversity and anti‐microbial resistance among staphylococci of dairy herds that originated from Paraiba State, north‐eastern Brazil, a region where such studies are rare. Milk samples (n = 552) were collected from 15 dairy farms. Isolates were evaluated for anti‐microbial susceptibility by Kirby–Bauer disc diffusion method. Confirmation of methicillin‐resistant Staphylococcus aureus (MRSA) was performed using multiplex PCR targeting mecA and nuc genes in addition to phenotypic assay based on PBP‐2a latex agglutination. Clonal relatedness of isolates was determined by pulsed‐field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) genotyping. Staphylococci were detected in 269 (49%) of the samples. Among these, 65 (24%) were S. aureus. The remaining 204 isolates were either coagulase‐negative staphylococci (n = 188; 70%) or coagulase positive other than S. aureus (n = 16; 6%). Staphylococci were cultured in seven (35%) of the 20 hand swab samples, from which five isolates were S. aureus. The isolates were most commonly resistant against penicillin (43%), ampicillin (38%) and oxacillin (27%). The gene mecA was detected in 21 S. aureus from milk and in one isolate from a milker's hand. None of the isolates were resistant to vancomycin. PFGE findings showed high clonal diversity among the isolates. Based on MLST, we identified a total of 11 different sequence types (STs 1, 5, 6, 83, 97, 126, 1583, 1622, 1623, 1624 and 1625) with four novel STs (ST1622‐ST1625). The findings show that MRSA is prevalent in milk from semi‐extensive dairy cows in north‐eastern Brazil, and further investigation on its extent in various types of milk production systems and the farm‐to‐table continuum is warranted.     

Expression of Mitochondria‐Associated Genes (PPARGC1A,NRF‐1, BCL‐2 and BAX) in Follicular Development and Atresia of Goat Ovaries

Most follicles undergo atresia during the developmental process. Follicular atresia is predominantly regulated by apoptosis of granulosa cells, but the mechanism underlying apoptosis via the mitochondria‐dependent apoptotic pathway is unclear. We aimed to investigate whether the mitochondria‐associated genes peroxisome proliferator‐activated receptor‐gamma, coactivator1‐alpha (PPARGC1A), nuclear respiratory factor‐1 (NRF‐1), B‐cell CLL/lymphoma 2 (BCL‐2) and BCL2‐associated X protein (BAX) played a role in follicular atresia through this pathway. The four mitochondria‐associated proteins (PGC‐1α, which are encoded by the PPARGC1A gene, NRF‐1, BCL‐2 and BAX) mainly expressed in granulosa cells. The mRNA and protein levels of PPARGC1A/PGC‐1α and NRF‐1 in granulosa cells increased with the follicular development. These results showed that these genes may play a role in the regulation of the follicular development. In addition, compared with healthy follicles, the granulosa cell in atretic follicles had a reduced expression of NRF‐1, increased BAX expression and increased ratio of BAX to BCL‐2 expression. These results suggested that changes of the mitochondria‐associated gene expression patterns in granulosa cells may lead to follicular atresia during goat follicle development.     

奶牛早孕因子重组蛋白的原核表达、纯化及多克隆抗体的制备

本研究旨在表达、纯化奶牛早孕因子重组蛋白及制备多克隆抗体.本试验构建奶牛早孕因子重组蛋白原核表达载体pET32a-EPF,转化至大肠杆菌BL21(DE3)内进行诱导表达,SDS-PAGE切胶纯化的早孕因子重组蛋白免疫BALB/c小鼠制备多克隆抗体,并用Western blotting和ELISA对重组蛋白及抗体进行检测.结果显示,成功表达并纯化了奶牛早孕因子重组蛋白,重组蛋白分子质量约37 ku,表达量约占菌体总蛋白的48.6%,纯化后目的蛋白纯度可达93%,重组蛋白可与所制备的多克隆抗体结合,ELISA测定的抗体效价为1:12 800.结果表明,本研究成功表达并纯化了奶牛早孕因子重组蛋白,为研究奶牛早孕诊断奠定基础.     

VPS28通过泛素化信号通路调控奶牛乳腺上皮细胞中乳蛋白的合成

旨在分析VPS28基因调控乳蛋白合成的分子机制，为奶牛泌乳性状的分子育种奠定理论基础。本研究首先利用RNA干扰（RNA interference，RNAi）技术敲降奶牛原代乳腺上皮细胞（bovine mammary epithelial cells，BMECs）中VPS28基因的表达水平，检测与乳蛋白合成、泛素化-溶酶体和泛素化-蛋白酶体通路相关的11个基因、泛素蛋白的表达水平及蛋白酶体活性；然后抑制BMECs中蛋白酶体和溶酶体的活性，检测酪蛋白相关基因、核糖体蛋白的表达水平；最后利用同位素标记相对和绝对定量（isobaric tags for relative and absolute quantification，iTRAQ）比较蛋白质组学分析敲降前后BMECs的差异表达蛋白。结果表明，敲降VPS28基因后，CSN1S1、CSN2、CSN3、RPS8、UBC、PSMC3、PSMC5基因均显著上调，PSMD12显著下调；抑制蛋白酶体后，CSN1S1、CSN2、CSN3显著上调，RPL13显著下调；抑制溶酶体活性后酪蛋白相关基因表达不显著；iTRAQ结果共筛选出129个差异表达蛋白，下调蛋白主要富集在核糖体、溶酶体、剪切体等相关通路，上调蛋白主要富集在内质网的蛋白质加工、加压素调控的水重吸收过程、RNA转运等通路中。研究表明，VPS28基因可通过泛素化信号通路影响BMECs中乳蛋白的合成。     

Molecular markers of prognosis in canine cortisol‐secreting adrenocortical tumours

Hypercortisolism is caused by a cortisol‐secreting adrenocortical tumour (ACT) in approximately 15%‐20% of cases in dogs. Little is known about which molecular markers are associated with malignant behaviour of canine ACTs. The objective of this study was to identify molecular markers of prognosis, which could be useful to refine prognostic prediction and to identify potential treatment targets. Cortisol‐secreting ACTs were included from 40 dogs, of which follow‐up information was available. The ACTs were classified as low risk of recurrence tumours (LRT; n = 14) or moderate‐high risk of recurrence tumours (MHRT; n = 26), based on the novel histopathological Utrecht score. Normal adrenals (NAs) were included from 11 healthy dogs as reference material. The mRNA expression of 14 candidate genes was analysed in the 40 ACTs and in 11 NAs with quantitative RT‐PCR. The genes' expression levels were statistically compared between NAs, LRTs and MHRTs. Univariate and multivariate analyses were performed to determine the association of the genes' expression levels with survival. Seven genes were differentially expressed between NAs and ACTs, of which pituitary tumour‐transforming gene‐1 (PTTG1) and topoisomerase II alpha (TOP2A) were also differentially expressed between LRTs and MHRTs. In survival analyses, high expression levels of Steroidogenic factor‐1 (SF‐1), PTTG1 and TOP2A were significantly associated with poor survival. In conclusion, we have identified several genes that are part of the molecular signature of malignancy in canine ACTs. These findings can be used to refine prognostic prediction, but also offer insights for future studies on druggable targets.