BoLA在牛抗病育种中的研究进展

BoLA基因同牛多种疾病和生产性状相联系,因此如何利用BoLA基因进行牛抗病育种是育种学家关心的问题,作者综述了BoLA基因同牛一些疾病的关系,并对BoLA基因进行牛抗病育种的现状及发展方向作了探讨。     

俄罗斯野麦草引种试验

俄罗斯野麦草青草产量,４７３７０ｋｇ／ｈｍ＾２,种子产量为２２９５ｋｇ／ｈｍ＾２,抗逆性强,适应范围广,返青早,枯黄期迟,青绿期长,利用价值高,适宜甘肃省绝大多数牧区和半农半牧区推广种植。     

副猪嗜血杆菌耐药性研究进展

作者主要对国内外副猪嗜血杆菌耐药性的研究进展进行综述,基于国内外副猪嗜血杆菌的最新耐药性研究报道,揭示了当前副猪嗜血杆菌的耐药性趋势,并根据其试验结果证明了前人提出的治疗方案确实、可靠,指出了目前治疗副猪嗜血杆菌病的有效药物,为养猪生产中综合防制副猪嗜血杆菌病提供了参考和依据。     

牛支原体耐药性研究进展

在对国内外牛支原体的耐药性研究进展做以综述的基础上,对近年来支原体的耐药机制进行了概述,以期为养牛业生产中牛支原体病的防治和耐药机制的研究提供参考.     

施用有机肥对当归药材性状、产量及抗病性的影响

为了探寻有机肥对当归成药栽培的影响,采用黑膜覆盖栽培,基施纯有机肥(O,2000 kg·hm-2)、纯化肥(C,磷酸二铵,420 kg·hm-2)、减半量化肥增施有机肥[1/2(O+C)],以不施肥为对照(CK),栽培期测定早期抽薹率、发病率、药材产量和性状指标.结果表明,纯有机肥栽培当归早期抽薹率为8.0％,分别较C...     

红三叶遗传图谱构建及抗白粉病基因QTL定位

本研究以感(岷山红三叶)、抗(澳大利亚红三叶品种♀Sensation×Renegade♂杂交新品系“甘农PR1”)白粉病红三叶材料为父母本杂交并种植成苗经人工接菌后筛选出抗、感白粉病的F₁群体为作图群体,利用AFLP标记构建红三叶高密度遗传图谱,并利用区间作图法对抗白粉病QTL进行了定位分析,可以为红三叶抗白粉病基因克隆和转基因等分子辅助育种奠定基础。结果表明,149个AFLP标记构建得到的遗传图谱包含7个连锁群(LG1,LG2,LG3,LG4,LG5,LG6和LG7),遗传图谱的总距离为640.5 cM。其中,LG1连锁群的遗传距离(140.6 cM)和标记间平均距离(9.4 cM)均最大;LG4连锁群的遗传距离(55.2 cM)和标记间平均距离(1.8 cM)最小。应用区间作图法对红三叶抗白粉病基因进行QTL分析定位,共检测到5个抗白粉病相关QTL位点(qrp-1,qrp-2,qrp-3,qrp-4和qrp-5),其中qrp-1、qrp-2、qrp-3和qrp-4位于LG4连锁群上,qrp-5位于LG5连锁群上。5个QTL位点对抗白粉病的贡献率为29%~90%,qrp-1对红三叶白粉病抗性的贡献率最大(90%),为主效QTL。     

Antimicrobial‐resistant Enterobacteriaceae recovered from companion animal and livestock environments

Antimicrobial‐resistant bacteria represent an important concern impacting both veterinary medicine and public health. The rising prevalence of extended‐spectrum beta‐lactamase (ESBL), AmpC beta‐lactamase, carbapenemase (CRE) and fluoroquinolone‐resistant Enterobacteriaceae continually decreases the efficiency of clinically important antibiotics. Moreover, the potential for zoonotic transmission of antibiotic‐resistant enteric bacteria increases the risk to public health. Our objective was to estimate the prevalence of specific antibiotic‐resistant bacteria on human contact surfaces in various animal environments. Environmental surface samples were collected from companion animal shelters, private equine facilities, dairy farms, livestock auction markets and livestock areas of county fairs using electrostatic cloths. Samples were screened for Enterobacteriaceae expressing AmpC, ESBL, CRE or fluoroquinolone resistance using selective media. Livestock auction markets and county fairs had higher levels of bacteria expressing both cephalosporin and fluoroquinolone resistance than did equine, dairy, and companion animal environments. Equine facilities harboured more bacteria expressing cephalosporin resistance than companion animal shelters, but less fluoroquinolone resistance. The regular use of extended‐spectrum cephalosporins in livestock populations could account for the increased levels of cephalosporin resistance in livestock environments compared to companion animal and equine facilities. Human surfaces, as well as shared human and animal surfaces, were contaminated with resistant bacteria regardless of species environment. Detecting these bacteria on common human contact surfaces suggests that the environment can serve as a reservoir for the zoonotic transmission of antibiotic‐resistant bacteria and resistance genes. Identifying interventions to lower the prevalence of antibiotic‐resistant bacteria in animal environments will protect both animal and public health.     

细菌生物被膜与抗生素耐药机制研究进展

细菌引发的感染已成为感染性疾病的主要原因之一,具有耐药性和难治性的特点,而且还可以对抗机体的免疫清除作用,对人类和动物的健康造成很大的危害,也给人们生活的其他方面带来了越来越严重的影响,引起了基础和临床研究的极大关注。但是细菌生物被膜对抗生素的耐药机制目前还不十分清楚,现对近年来细菌生物被膜对抗生素耐药形成的几种可能机制进行综述。     

Identification of the tet(B) resistance gene in Streptococcus suis

The tetracycline resistance gene, tet(B), has been described previously in Gram negative bacteria. In this study tet(B) was detected in plasmid extracts from 17/111 (15%) Streptococcus suis isolates from diseased pigs, representing the first report of this resistance gene in Gram positive bacteria.     

Measurement of C‐peptide concentrations and responses to somatostatin,glucose infusion,and insulin resistance in horses

Reasons for performing study: Hyperinsulinaemia is detected in horses with insulin resistance (IR) and has previously been attributed to increased pancreatic insulin secretion. Connecting peptide (C‐peptide) can be measured to assess pancreatic function because it is secreted in equimolar amounts with insulin and does not undergo hepatic clearance. Hypothesis: A human double antibody radioimmunoassay (RIA) detects C‐peptide in equine serum and concentrations would reflect responses to different stimuli and conditions. Methods: A validation procedure was performed to assess the RIA. Six mature mares were selected and somatostatin administered i.v. as a primed continuous rate infusion, followed by 50 nmol human C‐peptide i.v. Insulin and C‐peptide concentrations were measured in horses (n = 6) undergoing an insulin‐modified frequently sampled i.v. glucose tolerance test, and in horses with insulin resistance (n = 10) or normal insulin sensitivity (n = 20). Results: A human RIA was validated for use with equine sera. Endogenous C‐peptide secretion was suppressed by somatostatin and median (range) clearance rate was 0.83 (0.15–1.61) ml/min/kg bwt. Mean ± s.d. C‐peptide‐to‐insulin ratio significantly (P = 0.004) decreased during the glucose tolerance test from 3.60 ± 1.95 prior to infusion to 1.03 ± 0.18 during the first 20 min following dextrose administration. Median C‐peptide and insulin concentrations were 1.5‐ and 9.5‐fold higher, respectively in horses with IR, compared with healthy horses. Conclusions: Endogenous C‐peptide secretion decreases in response to somatostatin and increases after dextrose infusion. Results suggest that relative insulin clearance decreases as pancreatic secretion increases in response to dextrose infusion. Hyperinsulinaemia in insulin resistant horses may be associated with both increased insulin secretion and decreased insulin clearance. Potential relevance: Both C‐peptide and insulin concentrations should be measured to assess pancreatic secretion and insulin clearance in horses.