首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
Pituitary endocrine cells are supplied by Sox2-expressing stem/progenitor cells in the anterior lobe of the adult pituitary gland. These SOX2-positive cells are maintained in two types of microenvironments (niches): the marginal cell layer (MCL)-niche and the parenchymal-niche. Recently, we isolated dense SOX2-positive cell clusters from the parenchymal-niche by taking advantage of their resistance to protease treatment as parenchymal stem/progenitor cell (PS)-clusters. In the present study, by analyzing these isolated PS-clusters, we attempted to identify novel structural characteristics of pituitary stem/progenitor cell niches. Quantitative real-time PCR showed that tight junction-related genes were distinctly expressed in the isolated PS-clusters. Immunocytostaining showed that the tight junction molecules, ZO-1 and occludin, were localized in the apical membrane facing the pseudo-follicle-like structure of the isolated PS-clusters regardless of the expression of S100β, which distinguishes the sub-population of SOX2-positive cells. Furthermore, immunohistochemistry of the pituitary glands of adult rats clearly demonstrated that ZO-1 and occludin were densely present in the parenchymal-niche encircling the pseudo-follicle, while they were observed in the apical membrane in the MCL-niche facing the residual lumen. Collectively, these tight junction-related proteins might be involved in the architecture and maintenance of the plasticity of pituitary stem/progenitor cell niches.  相似文献   

3.
To develop the potential function of dairy cow mammary stem cells (DCMECs) in regulation of lactation,we identify putative DCMECs which were BrdU label retaining epithelial cells,at the same time,analysis the location of two new mammary stem cells molecular marks FNDC3B and PROCR to verify the feasibility of them to indicate DCMECs.The mRNA levels of prolactin,growth hormone,insulin-like growth factor-1 and their receptors were detected along with cell passage by Real-time quantitative PCR.The results showed that the proportion of BrdU label-retaining epithelial cells was nearly 0.4% after 25 d continuous culture (passaged 4 times) and few cells were positive for FNDC3B or PROCR.Moreover,we observed the BrdU labelled epithelial cells by asymmetric division.The mRNA levels of prolactin,growth hormone,insulin-like growth factor-Ⅰ and their receptors in primary and passage cells were extremely significant difference(P<0.01).DCMECs would rapidly lose some physiological characteristics and the ability of milk synthesis when not under the condition of induction of lactation differentiation,but a certain percentage of mammary stem/progenitor cells will be retained,whose potential effects on the regulation of lactation and mammary acinar remodeling were worthy of attention.  相似文献   

4.
为了揭示奶牛乳腺干细胞在体外泌乳调控中的潜在作用,本研究根据成体干细胞具有BrdU标记滞留的特点检测了奶牛乳腺上皮细胞(DCMECs)中疑似乳腺干/祖细胞,同时分析了两种新发现的乳腺干细胞分子标志(FNDC3B和PROCR)的表达定位,验证了它们指示DCMECs的可行性。通过实时荧光定量PCR方法检测分析DCMECs体外培养过程中催乳素、生长激素、胰岛素样生长因子Ⅰ及其受体的基因表达变化。结果显示,连续培养25 d后BrdU标记滞留细胞比例接近0.4%,极少数细胞呈FNDC3B或PROCR阳性,可以观察到不对称分裂细胞,原代和传代后DCMECs在激素、胰岛素样生长因子及其受体mRNA水平上差异极显著(P<0.01)。总之,在非诱导泌乳分化培养条件下,脱离泌乳生理环境的DCMECs自身具有的泌乳调控基因表达迅速受到抑制,但在一定培养时间内,DCMECs群体中能够保留一定比例疑似乳腺干/祖细胞,提示这些多能奶牛乳腺干/祖细胞在体外泌乳调控和乳腺腺泡重塑过程中可能发挥重要作用。  相似文献   

5.
Joint Nordic (Denmark, Finland, Sweden) genetic evaluation of female fertility is currently based on the multiple trait multilactation animal model (BLUP). Here, single step genomic model (ssGBLUP) was applied for the Nordic Red dairy cattle fertility evaluation. The 11 traits comprised of nonreturn rate and days from first to last insemination in heifers and first three parities, and days from calving to first insemination in the first three parities. Traits had low heritabilities (0.015–0.04), but moderately high genetic correlations between the parities (0.60–0.88). Phenotypic data included 4,226,715 animals with records and pedigree 5,445,392 animals. Unknown parents were assigned into 332 phantom parent groups (PPG). In mixed model equations animals were associated with PPG effects through the pedigree or both the pedigree and genomic information. Genotype information of 46,914 SNPs was available for 33,969 animals in the pedigree. When PPG used pedigree information only, BLUP converged after 2,420 iterations whereas the ssGBLUP evaluation needed over ten thousand iterations. When the PPG effects were solved accounting both the pedigree and the genomic information, the ssGBLUP model converged after 2,406 iterations. Also, with the latter model breeding values by ssGBLUP and BLUP became more consistent and genetic trends followed each other well. Models were validated using forward prediction of the young bulls. Reliabilities and variance inflation of predicted genomic breeding values (values for parent averages in brackets) for the 11 traits ranged 0.22–0.31 (0.10–0.27) and 0.81–0.95 (0.83–1.06), respectively. The ssGBLUP model gave always higher validation reliabilities than BLUP, but largest increases were for the cow fertility traits.  相似文献   

6.
不同牧草在奶牛瘤胃内的降解规律   总被引:2,自引:2,他引:0  
刘大林  赵丹  周洋  吕勇  吴敏  王留香  房震 《草业科学》2008,25(2):128-131
试验用尼龙袋法研究了不同种类牧草(黑麦草Lolium multiflorum、羊草Leymus chinese、返青期和盛花期紫花苜蓿Medicago sativa)的干物质(DM)、粗蛋白(CP)和粗纤维(CF)的在奶牛瘤胃内动态降解率变化规律.结果表明:在相同培养时间段内,返青期的紫花苜蓿DM的降解率显著高于黑麦草、羊草和盛花期的紫花苜蓿;不同生长期的紫花苜蓿其DM、CP的降解率差异显著(P<0.05),且返青期高于盛花期;各种牧草在48 h 的 CP 降解率都趋于平稳;经相关分析,各种牧草的DM、CP表现为强正相关关系.  相似文献   

7.
黑龙江省主要栽培的禾本科牧草对奶牛的营养价值评价   总被引:4,自引:0,他引:4  
通过对常见的13种栽培禾本科牧草的常规营养成分测定及用尼龙袋法测定的干物质在瘤胃72 h降解率(RDMD)的测定,结果表明:l)用营养成分和RDMD等指标进行评定,2个冰草Agropyron cristatum品种营养价值最高,猫尾草Phleum pratense次之,3个披碱草Puccinellia tenuiflora品种居中,羊草Leymuschinensis和墨西哥玉米Zea mays较差,谷莠子Setaria anceps和稗草Echinochloa crusgalli最差。2)禾本科牧草RDMD与ADF、ADL含量呈极显著负相关(P<0.05)。利用回归方程可以用ADF、ADL含量来预测禾本科牧草的RDMD。3)应用干物质采食量(DMI)、产奶净能(NEL)估测模型计算了各种禾本科牧草的分级指数(GI)值,并参照豆科和禾本科牧草质量分级标准对研究测定的禾本科牧草等级进行划分,其结果是:符合优质牧草等级的有高冰草、中间冰草,符合中等牧草等级标准的有无芒雀麦Bromus inermis、垂穗披碱草、东北羊草、吉生羊草、百特猫尾草、猎犬披碱草、润宝高丹草Sorghum×Sudan。属于劣质牧草的有粗穗披碱草Elymus dahuricus、墨西哥玉米、稗草、谷莠子。4)用单一的营养指标如化学成分、干物质降解率不能准确地评价牧草的营养价值。只有综合考虑DMI、养分含量、消化率和有效能才能对牧草的营养价值做出正确的评价。使用GI值能明显区分养分含量差异很小的不同种类牧草,这说明分级指数是评价牧草营养价值的最权威指标。  相似文献   

8.
为阐明金属硫蛋白在铜缺乏奶牛肝脏中的代谢特征 ,选择铜缺乏区有明显临床症状的奶牛 6头 ,采集肝脏样品后用差速离心法分离肝脏金属硫蛋白 ,以Sephadex G75进行层析纯化 ,测定各部分洗脱液中金属元素铜、锌、铁、镁的含量。将 6头健康奶牛的肝脏样品作为对照。试验结果表明 ,发病奶牛肝细胞浆Sephadex G75柱层析洗脱液中铜、铁含量峰值显著高于健康奶牛 ,且在后面部分层析液中出现小峰 ;发病奶牛肝细胞浆金属硫蛋白 (MT)层析液锌、镁含量曲线峰值宽阔且高于对照组 ,第 2峰形宽大且有前移现象。结论 :铜缺乏能够改变奶牛肝脏中金属硫蛋白的代谢  相似文献   

9.
Hepatic progenitor cells (HPCs) are bipotential stem cells residing in human and animal livers that are able to differentiate towards the hepatocytic or cholangiocytic lineages. HPCs are present in both hepatocellular (HCC) and cholangiocellular carcinoma (CC) in humans; and a small percentage of HCC can originate from cancer stem cells. However, its distribution in canine liver tumour has not been studied. Herein, we searched for stem/progenitor cells in 13 HCC and 7 CC archived samples by immunohistochemical analysis. We found that both liver tumours presented a higher amount of K19‐positive HPCs. Besides, 61.6% of HCC cases presented immature CD44‐positive hepatocytes. Nevertheless, only two cases presented CD133‐positive cells. As observed in humans, hepatic canine tumours presented activated HPCs, with important differentiation onto hepatocytes‐like cells and minimal role of cancer stem cells on HCC. These findings reiterate the applicability of canine model in the search for new therapies before application in humans.  相似文献   

10.
将免疫原性稳定的鹦鹉热衣原体SX5菌株灭活,加入油佐剂制备乳牛衣原体病灭活疫苗,并对疫苗的安全性进行了检测。用该疫苗对成年牛和犊牛进行了最小免疫量试验、效力试验和免疫持续期试验;结果表明,最小免疫量分别为3mL和5mL,平均免疫保护率达94.4%。免疫持续期达10个月。疫苗保存期试验表明,在4℃条件下可保存12个月。本动物安全试验和田间小试免疫证明,该疫苗安全性好,乳牛注射疫苗后饮食、产乳量及注苗部位没有明显的异常变化。  相似文献   

11.
文章综述了单菌株和多菌株微生态制剂在提高奶牛产奶性能上的应用,分析探讨了两种微生态制剂应用中存在的问题,并提出一些解决措施,为其进一步研究提供参考.  相似文献   

12.
全混合日粮对奶牛产乳性能的影响   总被引:4,自引:0,他引:4  
试验选用了12头奶牛,根据产奶量、泌乳天数和胎次相近的原则分为试验组和对照组,研究全混合日粮对奶牛产乳性能的影响。试验结果表明,试验组4%标准乳产量比对照组提高1 24kg,差异显著(P<0.05),乳脂率及乳脂、乳糖和乳固形物含量也分别比对照组显著提高11.60%、17.50%、13.21%和9.86%(P<0.05)。  相似文献   

13.
The objective of this study was to investigate the use of infrared thermography (IRT) for detection of foot lesions in dairy cattle. Thermal images of the rear feet of 139 lactating dairy cows were taken with a thermal camera and evaluated using imaging software. Foot lesions identified in the study included white line disease (WLD), sole ulcer (SU) and digital dermatitis (DD). Temperatures at the coronary band (CBT) and the skin (ST) were recorded. Cows were scored for locomotion on a scale of 1–5 (1?=?normal and 5?=?severely lame). CBT was higher for all types of foot lesion (34.1?±?2.3, 33.8?±?1.6 and 33.1?±?1.6°C for WLD, SU and DD, respectively) than for healthy (32.6?±?1.9°C) feet. ST was higher only for WLD (33.2?±?2.0°C) compared to healthy feet (31.5?±?1.7°C). ΔT (temperature difference between CBT and ST) was higher for SU (2.1?±?0.8°C) than healthy feet (1.1?±?0.9°C). Locomotion scores (LSs) were similar between healthy cows (2.2?±?0.7) and DD (2.4?±?0.7) but greater for SU and WLD cows (3.0?±?0.9, 3.0?±?0.8) than healthy cows. The threshold values established for CBT and ST were 33.5°C (sensitivity?=?77.8%, specificity?=?65.2%) and 33.7°C (sensitivity?=?44.4%, specificity?=?92.9%) for SU, and 34.4oC (sensitivity?=?28.1%, specificity?=?88.6%) and 31.8°C (sensitivity?=?60.7%, specificity?=?55.4%) for overall lesion, respectively. These results indicate that IRT can be a useful tool for detection of SU, but not WLD and DD. In addition, CBT and ΔT were the best indicators for the detection of foot lesions.  相似文献   

14.
15.
铜缺乏奶牛琥珀酸脱氢酶的组化特征   总被引:3,自引:0,他引:3  
为探讨铜缺乏对奶牛心脏、肝脏、肾脏琥珀酸脱氢酶 (SDHase)组化特征 (分布特点及活性 )的影响 ,本实验选择铜缺乏症高发区自然发病的奶犊牛 6头 ,剖杀后采集心、肝、肾作冰冻切片及酶组化染色 ,以 6头同年生健康奶犊牛为对照。实验结果表明 ,发病组奶牛心脏中 SDHase计数值显著高于对照组 (P<0 .0 5 ) ,而肝脏、肾脏中SDHase计数值显著低于对照组 (P<0 .0 5 ) ;健康组奶牛心脏、肝脏、肾脏中 SDH活性扫描值均显著大于发病组(P<0 .0 5 )。发病奶牛组组织中 SDHase酶颗粒的分布也发生特征性的变化。结论 :氧化呼吸链关键酶活性的改变是导致奶牛铜缺乏症病理过程的重要原因  相似文献   

16.
Summary

In a trial involving 542 dairy cattle on 28 farms, 276 were treated once with thiabendazole within two days of calving. The treated group showed an average increase in milk yielded over the non‐return group of 229.8 kg during the subsequent lactation.

In the treated group, total milk fat production was increased over that of the controls by 7.4 kg per cow; milk protein was increased by 6.9 kg per cow. All treatment parameter differences were highly significant at the 1% level of probability.  相似文献   

17.
直接饲喂微生物对奶牛瘤胃发酵和肠道的影响   总被引:1,自引:0,他引:1  
直接饲喂微生物(DFM)能够提高奶牛的日增重和饲料效率,增加奶牛的产奶量,改善犊牛的健康状况。然而其作用模式不是很明确。本文对目前应用在奶牛养殖方面直接饲喂微生物的种类及其与瘤胃和肠道的关系及作用模式进行综述。  相似文献   

18.
Corynebacterium pseudotuberculosis infection in an Israeli dairy cattle herd is described. The disease was characterized by ulcerative granulomatous lesions, which occurred in an epidemic form. Thirty-two cows and two heifers were affected, the ratio of the number affected to number at risk being 17.5 : 1 and 9.5 : 1, respectively. The culling rate was 50% of the affected animals. Most of the affected animals were cows (91.2%), with one first-calving cow (2.9%) and two heifers (5.9%) also affected. The infection occurred during the summer to autumn months (August-December), and lasted 118 days. The incubation period is about 2 months. The disease appeared in two clinical forms - cutaneous and mastitic - or as a mixed form. C. pseudotuberculosis organisms that were isolated from the ulcerative granulomatous lesions and from milk samples failed to reduce nitrate. A decrease in milk production (4%) and an increase in the bulk-milk somatic cell count from a herd mean of 240 x 10(3) mL(-1) to 460 x 10(3) mL(-1) were noted during the morbidity period. The organism was isolated from milk samples of eight animals (25%). Clinical, epizootiological and microbiological aspects of the infection are described.  相似文献   

19.
The antiradical function of sulfhydryl (SH) residue in dairy cattle plasma and the relationship of SH residue concentrations to other oxidative stress markers, ascorbic acid and thiobarbituric acid reactive substance (TBARS) in plasma were investigated. The concentration of reduced glutathione (GSH) in phosphate buffer solution (pH 7.6) and SH residues in dairy cattle plasma decreased significantly (P < 0.05) in vitro by the addition of peroxyradicals at 38°C, depending on incubation periods. The decrease of GSH concentration with the peroxyradical solution was partially protected by the addition of sodium ascorbate solution. A positive and significant correlation with SH residues and albumin concentration in the fresh plasma obtained from 15 dairy cattle was observed (P < 0.05). The SH residue concentration was not correlated with the TBARS concentration in plasma. The total ascorbic acid and SH residues concentration in the plasma correlated positively but not significantly (P < 0.10). These results suggested that SH residues in dairy cattle plasma play important part in the antiradical function.  相似文献   

20.
沈阳市某乳业公司奶牛钙、磷、β-胡萝卜素盈缺状况检查   总被引:1,自引:0,他引:1  
对沈阳市某乳业公司七个奶牛场牛群血中钙、磷、β-胡萝卜素含量进行抽检,从全群3,000多头成母牛中共抽检350头奶牛,其中包括84头高产奶牛、77头干奶牛、92头产后牛和97头有病牛。结果表明:全群牛血中钙、磷的平均含量偏低,血钙的最高值、平均值和最低值分别为3.32mmol/l、2.26 0.44mmol/l和1.53mmol/l,血磷的最高值、平均值和最低值分别为2.71mmol/l、1.72 0.51mmol/l和0.84mmol/l;血中钙、磷比例不当,其最大值、平均值和最小值分别为3.96:1.0、1.70:1.0和0.645:1.0:血中钙、磷含量乘积偏低,其最高值、平均值和最低值分别为63.74、48.20和24.50;血中β-胡萝卜素含量不足,其最高值、平均值和最低值分别为657μg/100ml、278.69 201.78μg/100ml和52μg/100ml,其中高产牛血中含量相对较高。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号