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排序方式: 共有416条查询结果,搜索用时 15 毫秒
1.
N. LA PORTA P. CAPRETTI K. KAMMIOVIRTA R. KARJALAINEN & K. KORHONEN 《Plant pathology》1997,46(5):773-784
Eighty-six Heterobasidion annosum isolates, mainly belonging to the F intersterility group and obtained from 32 different geographical localities in Italy, were subjected to genetic analysis by the Random Amplified Polymorphic DNA (RAPD) markers. The similarity between F and S groups was higher than that between F and P. In UPGMA Cluster Analysis, the F isolates originating from the same locality usually grouped in the same cluster. The isolates also showed a tendency to group at the level of larger geographical areas. Within the F group, isolates from the south of the Italian peninsula showed the highest genetic variation and northern isolates from the Alpine regions showed the lowest. This indicates a gradual cline along the peninsula. The genetic variability in the Italian F group is discussed in relation to the past and present distribution of the host species in Italy and Europe. 相似文献
2.
Laryngeal mask airway and transient hypercapnic hyperpnea for video‐endoscopic assessment of unilateral laryngeal paralysis in dogs 下载免费PDF全文
3.
Swai ES Karimuribo ED French NP Fitzpatrick JL Bryant MJ Kambarage DM Ogden NH 《Journal of the South African Veterinary Association》2007,78(1):15-20
Variations in the seroprevalence of antibody to Babesia bigemina infection by farm and animal level risk factors were investigated for 2 contrasting regions of Tanga and Iringa in Tanzania. Tanga is situated in the eastern part of the country and has typical tropical coast climate while Iringa is situated in the Southern Highlands and has a tropical highland climate. Two hundred farms from each region were selected using simple random sampling procedure and visited once between January 1999 and April 1999. Blood samples were collected from 1329 smallholder dairy animals on selected farms for harvesting serum which was subsequently used for serodiagnosis of B. bigemina using an indirect enzyme linked immuno-sorbent assay (ELISA). Of the 1329 sera samples screened, 34.9 % were positive for B. bigemina. The prevalence was higher in Iringa Region [43%, 95% confidence intervals (CI) = 39.5-47.3] than in Tanga Region (27%, CI = 23.6-30.5). Using a logistic binomial regression model as an analytical method for predicting the likelihood of animal seropositivity, we found (in both regions) that the risk of positive reaction varied with the animal's age, history of grazing and geographical location. Seroprevalence increased with age (beta = 0.01 and 0.01 per year of age, P < 0.005 in Tanga and Iringa, respectively). Animals located in Lushoto and Iringa urban district were associated with increased risk of seropositivity [Odds ratio (OR) = 4.24, P = 0.001, for Lushoto, and OR = 1.81, P = 0.040, for Iringa Urban, respectively). Animals grazed 3 months prior to sampling had higher odds for seropositivity than zero/semi-grazed, despite farmer-reported high frequency of tick control (OR = 2.71, P = 0.0087, for Tanga, and OR = 4.53, P = 0.001, for Iringa). Our study suggests that even though herd sizes are small, B. bigemina infection is widespread in many smallholder dairy farms and endemic stability with respect to this disease has not yet been attained, but the observed levels are sufficiently high to ensure that clinical disease would be a risk. 相似文献
4.
甜菜SSR反应体系优化及重要农艺性状分子标记 总被引:5,自引:0,他引:5
[目的]为选育优质甜菜新品种,利用SSR法筛选与高糖、高产、耐盐相关的分子标注.[方法]研究对甜菜SSR-PCR反应体系进行优化,并利用SSR分子标记方法和分离群体分组分析法(Bulked SegregateAnalysis,BSA)对具有高糖/低糖、低产/高产、耐盐/不耐盐三种重要农艺性状的甜菜亲本和F2代植株进行分析.[结果]研究建立了适宜甜菜的SSR-PCR反应体系为:20μL反应体系中含l×Buffer、2.0 mmol/LMg2+、1.5 uTaq DNA聚合酶、0.20 mmol/L dNTP、1.5 μmol/L引物、60 ng DNA模板.依据优化体系,对不同农艺性状的甜菜亲本与F2代进行SSR-PCR扩增分析,高糖性状获得了200和100 bp两条与高糖性状连锁的标记,250和230 bp两条与高产性状连锁的标记,550、250和100 bp三条与耐盐性状紧密连锁的分子标记.[结论]研究获得的7条特异条带是与甜菜重要农艺性状连锁的分子标记,将为甜菜的育种工作提供重要的理论基础. 相似文献
5.
【目的】为鉴定绵羊乳酸脱氢酶β(lactate dehydrogenase B,LDHβ)基因的分子特征,研究其在不同剩余采食量绵羊肝脏和肌肉组织中的表达差异.【方法】测定了137只‘湖羊’公羔的剩余采食量(residual feed intake,RFI),按RFI进行排序,分别筛选出RFI最高(high-residual feed intake,H-RFI)和RFI最低(low-residual feed intake,L-RFI)的羊各15只,屠宰后,采集肝脏和肌肉组织,利用Q-PCR技术检测绵羊LDHβ基因分别在H-RFI和L-RFI羊肝脏和肌肉中表达量,并利用生物信息学软件构建了该基因的系统进化树和预测其结构与功能.【结果】绵羊LDHβ基因开放阅读框(open reading frame,ORF)为1 005bp,编码334个氨基酸,其蛋白质分子质量为36 479.43U,理论等电点为6.40.绵羊LDHβ基因与山羊的亲缘关系较近,其次为牛,序列同源性高.功能结构域预测结果显示,该基因编码产物在内质网中参与辅酶因子生物合成的可能性最高.Q-PCR结果显示,绵羊LDHβ-mRNA基因在L-RFI羊肝脏和肌肉中表达量均显著低于H-RFI羊(P0.01).【结论】绵羊LDHβ基因作为能量代谢的关键酶参与绵羊饲料效率的调控. 相似文献
6.
LA Barre W McAllester DP Slotkin JS Stewart OC Tax S 《Science (New York, N.Y.)》1951,114(2970):582-583
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Signs of ascites were observed in only nine of 1863 cattle examined over a period of five years. The ascites was most commonly associated with either primary or secondary cardiac disease; cattle with ascites have a poor prognosis because the condition is usually assocaited with terminal disease. Two animals had cor pulmonale with chronic pneumonia, three had cardiomyopathy, one had bacterial endocarditis, two had thrombosis of the caudal vena cava and one had diffuse abdominal epithelioid mesothelioma. 相似文献
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10.
Farmers recorded the clinical signs of cows with clinical mastitis and submitted milk samples for bacteriological examination, so that the clinical signs could be correlated with the bacteriological findings. Odds ratios for the demeanour of the cow, the appearance of the milk, milk yield, udder texture, and the administration of parenteral antibiotics were calculated for mastitis cases classified in terms of their microbiology as either enterobacteriaceae, major Gram-positive pathogens, minor pathogens, 'no growths' or 'all other pathogens'. Animals infected with enterobacteriaceae had the highest odds of being reported as having a reduced milk yield, swollen or hard udders, watery milk and/or being systemically sick. A logistic regression model was used to predict the Gram-staining characteristics of the bacteria causing clinical mastitis. The clinical findings found to be significant predictors in the model were the demeanour of the cow and its milk yield. The regression model was used as a basis for a predictive test. Using a test data set, the sensitivity of the test was 28 per cent, its specificity was 96 per cent, the positive predictive value was 74 per cent and the negative predictive value was 80 per cent. The overall accuracy of these predictions was 79 per cent. 相似文献