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 35 毫秒
1.
对中国内蒙古自治区饲育马土壤环境中马红球菌的分布知之甚少;为此,在中国内蒙古通辽近郊、内蒙古南部锡林郭勒盟大草原、内蒙古东部呼伦贝尔大草原等马场共收集了108份土壤样品进行了马红球菌的检测。结果,锡林郭勒盟大草原和呼伦贝尔大草原的马红球菌分离率为25.9%～30.0%,通辽近郊土壤中分离率高达82.3%。这说明在通辽近郊马红球菌的分离菌数是草原土壤中马红球菌分离菌数的10倍。应用PCR技术检测了488株的毒力相关基因,相对分子质量分别为15000～17000（VapA）和20000（VapB）。所有的分离株都未检出毒力相关基因。这些无毒力分离株的质粒资料显示,各种大小的潜在质粒的发生率为13.3%～21.5%。本研究结果截然不同于我们新近对蒙古国的调查结论：马红球菌在蒙古国乌兰巴托的马群中不存在。造成这一差异的原因可能在于蒙古国的游牧生活和内蒙古的非游牧生活。  相似文献   

2.
The absence of Rhodococcus equi in Mongolian horses   总被引：1，自引：0，他引：1  
In native Mongolian horses, the incidence and distribution of Rhodococcus equi are poorly understood. One hundred and fourteen equine fecal samples and 71 soil samples were collected from the camp sites of 26 nomadic families located in three areas less than 100 km from Ulaanbaatar, Mongolia. Five fecal samples were also collected from foals of Przewalski's Horses introduced into the Hustai National Park, Mongolia. No R. equi was isolated from the Mongolian horses or the soil samples. However, three colonies of R. equi were isolated from two fecal samples collected from foals of Przewalski's Horses. These isolates were avirulent, with neither 15- to 17-kDa antigens (VapA) nor a 20-kDa antigen (VapB) genes being detected. We concluded that native Mongolian horses and their environment appear free from contamination with R. equi.  相似文献   

3.
We recently demonstrated the presence of virulence-associated protein antigen (VapA)-positive Rhodococcus equi in Jeju Island, Korea. These bacteria contained one of two distinct plasmid types, a 90-kb type II plasmid, which has been found in isolates from the native Kiso horses of Japan, and a new variant, a 90-kb type V plasmid. However, the genotypic characters of the VapA-positive R. equi from Jeju native horses and their environments are poorly understood. Ninety-eight isolates from soil samples and 89 isolates from fecal samples were collected from five farms that breed or have bred Jeju native horses, and were tested for the presence of VapA by immunoblotting and PCR. Of the 98 soil isolates and 89 fecal isolates, seven and 13 were VapA-positive R. equi, respectively. In 2003, two Jeju foals died suddenly and were brought to the Faculty of Veterinary Medicine, Cheju National University, for postmortem examination. Pure cultures of R. equi were isolated from the lung lesions of both foals. Of the 16 clinical isolates, 14 were VapA-positive R. equi. Of the 34 VapA-positive clinical and environmental isolates, 16 contained the 90-kb type II plasmid and 18 contained a 90-kb type V plasmid. Pulsed-field gel electrophoresis (PFGE) patterns of the VapA-positive isolates from Jeju horses and Kiso horses, containing the 90-kb type II plasmid, were compared and formed two distinct groups. Furthermore, 18 virulent isolates containing the 90-kb type V plasmid formed two distinct PFGE groups (of 16 and two isolates). These results demonstrate that two virulence plasmid types are widespread in R. equi in Jeju native horses. However, there is little diversity in the PFGE patterns of virulent isolates, suggesting the clonal spread of virulent R. equi. The PFGE pattern of the virulent R. equi isolates from Jeju native horses in Korea is not identical to those of Kiso native horses in Japan.  相似文献   

4.
Isolation of virulent Rhodococcus equi from native Japanese horses   总被引：1，自引：0，他引：1  
R. equi was isolated from soil samples obtained from the environment of seven native Japanese horse breeds (Hokkaido, Kiso, Noma, Misaki, Tokara, Miyako and Yonaguni) and from fecal samples collected from three native horse breeds (Hokkaido, Kiso and Misaki). Virulent R. equi at various levels (ranging from 0.5 to 12.9%) was isolated from the feces or soil environment of Hokkaido, Kiso and Misaki horses. Isolates were investigated both for the presence of 15- to 17-kDa antigens (virulence-associated protein antigens; VapA) by colony blotting, using the monoclonal antibody 10G5, and the gene of VapA by PCR. Plasmid DNAs extracted from positive isolates were digested with restriction endonucleases, and the digestion patterns of the plasmids of virulent isolates were divided into three types. Two of the three types (87-kb type II and 90-kb type I) had already been reported in Japanese isolates, and a new type (tentatively designated as 90-kb type II) had been found in isolates from Kiso horses. Six virulent R. equi isolates from the Hokkaido horses contained an 87-kb type II plasmid. Eight of 24 isolates from the Kiso horses contained an 87-kb type II plasmid, and the remaining 16 contained a 90-kb type II (a new type) plasmid. Two isolates from the Misaki horses contained a 90-kb type I plasmid. These results demonstrate the geographic difference in the distribution of virulence plasmids in R. equi isolates among native Japanese horses.  相似文献   

5.
OBJECTIVE: To determine whether isolation and virulence of Rhodococcus equi from soil and infected foals are associated with clinical disease. DESIGN: Cross-sectional and case-control study. SAMPLE POPULATION: R equi isolates from 50 foals with pneumonia and soil samples from 33 farms with and 33 farms without a history of R equi infection (affected and control, respectively). PROCEDURE: R equi was selectively isolated from soil samples. Soil and clinical isolates were evaluated for virulence-associated protein antigen plasmids (VapA-P) and resistance to the beta-lactam antibiotics penicillin G and cephalothin. Microbiologic cultures and VapA-P assays were performed at 2 independent laboratories. RESULTS: VapA-P was detected in 49 of 50 (98%) clinical isolates; there was complete agreement between laboratories. Rhodococcus equi was isolated from soil on 28 of 33 (84.8%) affected farms and 24 of 33 (72.7%) control farms, but there was poor agreement between laboratories. Virulence-associated protein antigen plasmids were detected on 14 of 66 (21.2%) farms by either laboratory, but results agreed for only 1 of the 14 VapA-P-positive farms. We did not detect significant associations between disease status and isolation of R equi from soil, detection of VapA-P in soil isolates, or resistance of soil isolates to beta-lactam antibiotics. No association between beta-lactam antibiotic resistance and presence of VapA-P was detected. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of soil microbiologic culture and VapA-P assay results, it is not possible to determine whether foals on a given farm are at increased risk of developing disease caused by R equi.  相似文献   

6.
Rhodococcus equi isolates (462) obtained from 64 soil samples collected on 5 R. equi-endemic horse-breeding farms and isolates from 100 infected foals in Texas were examined to determine the prevalence and genotypic diversity of virulence-associated plasmids. Isolates were tested for the presence of 15-17-kDa virulence-associated protein antigens (VapA) by immunoblotting and virulence-associated plasmids by PCR. Plasmid DNAs were isolated and analyzed by digestion with restriction endonucleases for estimation of size and comparison of polymorphisims. Rhodococcus equi were isolated from soil of all 5 farms; however, virulent R. equi were only isolated from 3 of the 5 farms and represented 18.8% (87 of 462) of total isolates. Of the 87 virulent soil isolates, 56 (64.5%) contained an 85-kb type I plasmid, 23 (26.4%) an 87-kb type I plasmid, 7 (8%) a newly defined 85-kb type III plasmid (Tx 43), and 1 (1.1%) a newly defined 85-kb type IV plasmid (Tx 47). Of the 100 isolates from infected foals, 96 were virulent. Of the 96 virulent isolates, 51 (53.1%) contained an 85-kb type I plasmid, 39 (40.6%) an 87-kb type I plasmid, 4 (4.2%) an 85-kb type III plasmid (Tx 43), and 2 (2.1%) an 85-kb type IV plasmid (Tx 47). There are at least 4 different R. equi virulence-associated plasmids in Texas, 2 of which have not previously been described. Based upon virulence plasmid typing, there is geographic diversity among isolates of R. equi from clinical and environmental samples on horse-breeding farms in Texas. There is not a strong correlation between the presence of virulent R. equi in farm soils and the R. equi disease status of those farms.  相似文献   

7.
The prevalence of virulent Rhodococcus equi in soil isolates from two horse farms in South Africa and nine clinical isolates from six foals, a foal foetus, a dog, and a monkey was investigated. The isolates were tested for the presence of virulence plasmid DNA and 15- to 17-kDa antigens by immunoblotting. Rhodococcus equi was isolated from almost all of the soil samples obtained from the two farms with 5.0 x 10(1) to 3.3 x 10(4) colony forming units per gram of soil. Virulent R. equi was isolated from three soil samples from one of the farms and appeared in 3.8% (three of 80 isolates), but not in any of the 182 isolates from the other farm. Of the three virulent R. equi isolates, one contained an 85-kb type I plasmid and two an 87-kb type I plasmid. Of nine clinical isolates from the foals, foal foetus, dog and monkey, five from the foals were virulent R. equi which expressed the virulence-associated antigens and contained a virulence plasmid 85-kb type I, and were all isolated from cases of pneumonia typical of that induced by R. equi in young foals living in widely separated areas in South Africa. The isolates from the other four foals, the dog and the monkey were avirulent R. equi.  相似文献   

8.
Rhodococcus equi was isolated from fecal and soil samples from four native Jeju horse farms and six Thoroughbred farms in Jeju, Korea. The isolates were examined for the presence of virulence-associated 15-17-kDa antigens (VapA) by colony blotting, using the monoclonal antibody 10G5, and for the gene encoding VapA by PCR. R. equi was isolated from all 36 soil samples collected from the 10 farms with between 5.0 x 10(2) and 7.5 x 10(4) colony-forming units (cfu) per gram of soil, and from 37 of 40 fecal samples with between 5.0 x 10(1) and 1.1 x 10 (5) cfu per gram of feces. Virulent R. equi was isolated from seven farms and appeared in 2.0% of isolates (10 of 508). Of the 10 virulent isolates, four contained a 90-kb type II plasmid, which has been found in isolates from the Kiso native horses of Japan, and the other six contained a new variant, which did not display the EcoRI and EcoT22I digestion patterns of the 10 representative plasmids already reported (85-kb types I, II, III, and IV; 87-kb types I and II; 90-kb types I, II, III, and IV). We designated the new variant as the "90-kb type V" plasmid, because its EcoRI digestion pattern is similar to that of the 90-kb type II plasmid. This is the first report of the prevalence of virulent R. equi in Jeju, Korea. The same virulence plasmid type is found in both Korean and Japanese isolates, providing insight into the origin, ancestry, and dispersal of native horses in Korea and Japan.  相似文献   

9.
Rhodococcus equi isolates (204) obtained from foals (lung abscesses, lymph nodes, nasal discharge, rectal swabs) bred in 15 studs located throughout Hungary, isolates from soil samples, lymph nodes of pigs and from lesions of human patients were examined to determine genotypic diversity of virulence-associated plasmids. Isolates were tested for the presence of 15-17 kDa virulence-associated protein antigen (VapA) and 20k Da (VapB) genes by polymerase chain reaction (PCR). Plasmid DNAs were isolated and analysed by digestion with restriction endonucleases for estimation of size and comparison of polymorphisms. Of 146 clinical isolates from foals in 15 studs, 129 (88.3%) gave positive results for the VapA gene, showing a 564 bp product of the expected size in the PCR amplification. Of the 129 clinical isolates from foals, 123 contained an 85 kb type I plasmid and the remaining six contained an 87 kb type I plasmid. Of 48 soil isolates from two horse studs, 26 (54.2%) were positive for VapA gene and contained an 85 kb type I plasmid. Of three pig isolates, one was positive for VapA gene and contained an 85 kb type I plasmid, and the remaining two were positive for the VapB gene, showing a 827 bp product of the expected size in the PCR amplification and were R. equi of intermediate virulence which contained a 95 kb type S5 plasmid. Of the seven human isolates, five were positive for VapB gene by PCR, these were R. equi of intermediate virulence, which contained a 95 kb type S5 plasmid. These results revealed that virulent R. equi strains harbouring a virulence plasmid of 85 kb type I or 87 kb type I, which have been found in clinical isolates from Europe and North and South America, are widespread in Hungary. Furthermore, same intermediately virulence plasmid type was found in both human and pig isolates.  相似文献   

10.
[目的]研究内蒙古典型草地不同时期土壤及植被营养状况的差异及变化特点，为内蒙古典型草地的合理利用、退化草地的恢复治理以及畜牧业的可持续发展提供参考。[方法]从内蒙古不同地区典型草原选取8个监测点，包括G1（鄂温克草原，温性草甸草原，呼伦贝尔市）、G2（乌拉特草原，荒漠草原，巴彦淖尔市）、G3（天然草滩，乌兰察布市）、G4（辉腾锡勒草原，五花草甸草原，乌兰察布市）、G5（科尔沁草原，温性草甸草原，通辽市）、G6（人工牧草种植地，赤峰市）、G7（乌拉特草原，荒漠草原，包头市）、G8（格根塔拉草原，荒漠草原，乌兰察布市）；于2020年牧草返青期、旺盛期、枯萎期分别从不同监测点样方中取0~20 cm土层土样及植物样品地上部分，测定土壤和植物中的常规养分含量；利用主成分分析法计算不同监测点不同时期土壤及植被营养水平的综合得分并排序。[结果]返青期、旺盛期、枯萎期土壤全氮含量均为G4监测点（辉腾锡勒草原）最高，极显著（P<0.01）高于其他监测点；旺盛期、枯萎期G7监测点（包头市境内乌拉特草原）最低。3个时期土壤有效磷含量均为G6监测点（人工牧草种植地）最高，显著（P<0.05）或极显著（P<0.01）高于其他监测点。3个时期土壤有机质含量均为G4监测点（辉腾锡勒草原）最高，极显著（P<0.01）高于其他监测点，G7监测点（包头市境内乌拉特草原）最低。返青期G6监测点（人工牧草种植地）的植被氮、磷、钾含量均为最高，极显著（P<0.01）高于其他监测点。旺盛期G8监测点（格根塔拉草原）的植被氮、钾含量最高，G6监测点（人工牧草种植地）的植被磷含量最高。枯萎期G3监测点（乌兰察布市境内天然草滩）的植被氮、磷含量最高，G4监测点（辉腾锡勒草原）的植被钾含量最高。3个时期植被粗纤维含量均是G5监测点（科尔沁草原）最高，G4监测点（辉腾锡勒草原）最低。土壤营养状况评分为：G4监测点（辉腾锡勒草原）3个时期评分均较高，G7监测点（包头市境内乌拉特草原）3个时期评分均最低；植被营养状况评分为：G2监测点（巴彦淖尔市境内乌拉特草原）及G6监测点（人工牧草种植地）返青期>旺盛期>枯萎期，其余监测点均是旺盛期>返青期>枯萎期。[结论]内蒙古典型草原的土壤及植被养分含量存在明显的时空差异。总体来看，草甸草原返青期、旺盛期、枯萎期土壤中养分综合评分较高，荒漠草原3个时期评分较低；不同草原类型的植被养分综合评分在旺盛期较高，枯萎期较低。  相似文献   

11.
Ecology of Rhodococcus equi   总被引：7，自引：0，他引：7  
A selective broth enrichment technique was used to study the distribution of Rhodococcus equi in soil and grazing animals. Rhodococcus equi was isolated from 54% of soils examined and from the gut contents, rectal faeces and dung of all grazing herbivorous species examined. Rhodococcus equi was not isolated from the faeces or dung of penned animals which did not have access to grazing. The isolation rate from dung was much higher than from other samples and this was found to be due to the ability of R. equi to multiply more readily in dung. Delayed hypersensitivity tests were carried out on horses, sheep and cattle, but only horses reacted significantly. The physiological characteristics of R. equi and the nature of its distribution in the environment suggested that R. equi is a soil organism.  相似文献   

12.
OBJECTIVE: To evaluate sensitivity and specificity of a multiplex polymerase chain reaction (PCR) assay for simultaneous detection of Rhodococcus equi and differentiation of strains that contain the virulence-associated gene (vapA) from strains that do not. SAMPLE POPULATION: 187 isolates of R equi from equine and nonequine tissue and environmental specimens and 27 isolates of bacterial species genetically or morphologically similar to R equi. PROCEDURE: The multiplex PCR assay included 3 gene targets: a universal 311-bp bacterial 16S ribosomal RNA amplicon (positive internal control), a 959-bp R equi-specific target in the cholesterol oxidase gene (choE), and a 564-bp amplicon of the vapA gene. Duplicate multiplex PCR assays for these targets and confirmatory singleplex PCR assays for vapA and choE were performed for each R equi isolate. An additional PCR assay was used to examine isolates for the vapB gene. RESULTS: Results of duplicate multiplex and singleplex PCR assays were correlated in all instances, revealing high specificity and reliability (reproducibility) of the vapA multiplex assay. Of the pulmonary isolates from horses with suspected R equi pneumonia, 97.4% (76/78) yielded positive results for vapA. Seven of 50 (14%) human isolates of R equi yielded positive results for vapA. Six human R equi isolates and 1 porcine isolate yielded positive results for vapB. No isolates with vapA and vapB genes were detected. CONCLUSIONS AND CLINICAL RELEVANCE: The multiplex PCR assay is a sensitive and specific method for simultaneous confirmation of species identity and detection of the vapA gene. The assay appeared to be a useful tool for microbiologic and epidemiologic diagnosis and research.  相似文献   

13.
旨在调查引起内蒙古通辽地区奶牛乳房炎发生的优势病原菌。采用常规方法对采集自该地区某奶牛场的3份临床型乳房炎患牛奶样进行优势致病菌的分离鉴定,采用纸片扩散法（K-B法）评价分离菌对兽医临床常用抗菌药物的敏感性。结果表明,从3份乳样中共分离到14株菌,经生化试验鉴定为无乳链球菌;药敏试验结果表明,分离菌对链霉素及磺胺嘧啶表现出较强的耐药性,而卡那霉素、庆大霉素及麦迪霉素对分离菌则表现出较好的抑菌效果。  相似文献   

14.
为了确定内蒙古地区侵袭牛的双翅目昆虫种类与数量及其与气候的相关性，并确定昆虫对牛体产生的护体行为反应与双翅目昆虫数量之间的相关性。在内蒙古包头市、锡林郭勒盟、呼伦贝尔市、赤峰市和通辽市各选取10头年龄相似、体况相近的荷斯坦奶牛，对当地气候，双翅目昆虫种类、数量以及牛引起护体行为进行测定与统计。结果表明：内蒙古主要牛产地气候的差异与双翅目昆虫的数量之间无相关性（P〉0．05）；侵袭牛的双翅目昆虫种类主要是家蝇、厩螫蝇，部分地区存在大量的东方角蝇；双翅目昆虫的侵袭引起牛的护体行为反应，在护体行为中摆耳、颤动皮肤、踢腿、甩头均与侵袭牛体特定部位的昆虫数量有显著相关性（P〈0．05），而牛的摆尾行为发生频率较高，但与昆虫数量无相关性（P〉0．05），形成习惯性摆厘．  相似文献   

15.
试验旨在分析内蒙古生鲜乳中氨基酸含量、乳蛋白营养价值及其在不同地区的差异，为生鲜乳营养品质评定提供理论依据。选取内蒙古呼伦贝尔市、锡林郭勒盟、乌兰察布市、赤峰市、呼和浩特市、兴安盟、通辽市7个代表地区，采集同一季节70批次奶罐奶，用于分析内蒙古生鲜乳中17种氨基酸含量，并用FAO（2011）推荐的最新氨基酸评分模式评价乳蛋白营养价值，同时比较地区差异。结果表明：内蒙古生鲜乳中氨基酸总量为3.117%，其中谷氨酸含量最高（0.593%），其次是脯氨酸、亮氨酸、赖氨酸，甘氨酸和胱氨酸含量最低（0.060%和0.061%）。内蒙古生鲜乳中必需氨基酸（EAA）构成比例及氨基酸评分均高于FAO/WHO理想蛋白质标准和模式。内蒙古不同地区生鲜乳氨基酸含量存在较大差异，主要表现为：与赤峰市生鲜乳中氨基酸含量相比，锡林郭勒盟生鲜乳中EAA、非必需氨基酸（NEAA）和总氨基酸（TAA）的含量优势明显（P<0.05），呼伦贝尔市生鲜乳中缬氨酸、赖氨酸、组氨酸、甘氨酸、丙氨酸的含量较高（P<0.05），呼和浩特市生鲜乳中亮氨酸、赖氨酸、组氨酸、丙氨酸、天冬氨酸和酪氨酸含量相对较高（P<0.05），其他几个盟市差异不显著（P>0.05）。综合上述试验结果，内蒙古生鲜乳中乳蛋白为优质蛋白，其中锡林郭勒盟、呼伦贝尔市和呼和浩特市生鲜乳氨基酸营养价值相对较高。  相似文献   

16.
Pulsotypes of VapA positive Rhodococcus equi isolated from foals and soil on a farm in Germany were characterized on the basis of nasal and tracheal samples simultaneously collected in 2003 from 217 foals with sonographic evidence of pneumonia or pulmonary abscesses. Of the 217 double samples, R. equi was isolated in 118 (54%) of the tracheal samples and in 52 of the nasal swab samples (24%) (P<0.001). Furthermore, 37 and 55 isolates were also randomly selected from nasal swabs and the tracheal samples, respectively, and further processed to determine the presence of VapA by colony blot enzyme-linked immunosorbent assay. This method showed that 26 (68%) of the nasal swabs and 40 (73%) of the tracheal samples were VapA-positive. R. equi was isolated from 56 (87%) of the 64 soil samples taken from the paddocks and stables in March and from 17 (68%) of the 25 samples taken in July of 2003. Three (21%) of these randomly selected 14 isolates from March and 13 (81%) of the 16 from July were VapA-positive. The VapA positive isolates from foals and soil were genotyped by plasmid profiling, restriction fragment length polymorphism analysis and pulsed-field gel electrophoresis. Of the 83 isolates, 80 contained an 85-kb type I plasmid and three contained an 87-kb type I plasmid. Pulsed-field gel electrophoresis yielded four distinct VspI profiles dividing 83 isolates into three major (A1, 51; D, 14; and 11 isolates) and three minor (C, 4; A3, 2; and A2, 1 isolates) groups. These results suggest that the majority of foals were exposed to and infected with three pulsotypes of VapA positive R. equi containing an 85-kb type I plasmid.  相似文献   

17.
Rhodococcus equi has been isolated from the submaxillary lymph nodes of domesticated pigs, but little is known about the presence of R. equi in wild boars. The aim of the study was the evaluation of the incidence of R. equi in wild boars and the characterisation of them. Of 482 submaxillary lymph nodes of wild boars shot in 39 settlements throughout Hungary, R. equi was isolated from 60 specimens, and plasmid types of 82 isolates were examined. The isolates were tested for the presence of 15-17-kDa (VapA) and 20-kDa virulence-associated protein antigen (VapB) genes by polymerase chain reaction (PCR). Plasmid DNAs were isolated and analysed by digestion with restriction endonucleases to estimate size and compare their polymorphisms. None of the 82 isolates contained vapA gene but 21 isolates (25.6%) were positive for vapB gene showing 827bp product of the expected size in the PCR amplification. Sixty-one strains (74.4%) did not contain plasmid. The 21 isolates of intermediate virulence contained virulence plasmids that were identified as types 1 (1 isolate), 5 (16 isolates), 21 (1 isolate), and three new distinct plasmid variants (1-1-1 isolate), respectively. On the basis of restriction digestion patterns of plasmid DNAs, we tentatively designated the new variants as types 25-27, respectively. The prevalence of R. equi strains of intermediate virulence among the isolates originated from the submaxillary lymph nodes of wild boars (25.6%) is very similar to those of domestic pigs (26.8%) in Hungary, and plasmid type 5 is the predominating one in both groups. This is the first report of isolation of VapB-positive R. equi from wild boars in the world.  相似文献   

18.
扁蓿豆是异花授粉的多年生二倍体植物，分布于内蒙古中东部地区。利用SDS聚丙烯酰胺垂直板凝胶电泳技术对采自内蒙古5个地区的20个居群的种子贮藏蛋白质进行了研究。结果表明，供试材料蛋白质分子量介于140kDa-13kDa之间，共在36个点位出现了蛋白质带。分子量为41kDa、31kDa及13kDa点位的3条带在供试材料中全部出现。另外，第1和第17点位带表现频度比较低。对20个居群蛋白质带信息进行相异性平均聚类分析，共聚为六类：聚类Ⅰ包括赤峰市2个居群和锡林郭勒盟1个居群；聚类Ⅱ包括赤峰市1个居群、锡林郭勒盟2个居群和乌兰察布市2个居群；聚类Ⅲ包括通辽市1个居群、赤峰市2个居群、锡林郭勒盟2个居群和呼和浩特市1个居群；聚类Ⅳ包括呼和浩特市1个居群和乌兰察布市2个居群；聚类Ⅴ包括呼和浩特市和乌兰察布市各1个居群；聚类Ⅵ只有锡林郭勒盟1个居群。据此推测，扁蓿豆是蛋白质多样性的种群。  相似文献   

19.
Horse farms in Kansas were surveyed for the incidence of Rhodococcus equi. Fecal specimens and soil or cobweb samples were collected from each farm and cultured on selective media. One control farm (with no history of R. equi infection), one farm which had an outbreak 3 and 4 years previously and 2 farms which had R. equi-infected foals that season were surveyed. In addition, fecal samples from 21 horses hospitalized in the Kansas State University Veterinary Hospital were cultured. There was no significant difference in the incidence of R. equi in fecal samples from the 2 farms with recent disease problems. The farm with a history of disease had a significantly higher percentage of positive fecal cultures than the 2 farms with a more recent history of disease. Neither ration composition nor sex of the horses appeared to affect the fecal culture results. Fecal samples from 2 birds on 1 farm were positive for R. equi.  相似文献   

20.
氮肥对沙地燕麦生长特性及产量的影响   总被引：1，自引：0，他引：1  
在内蒙古通辽市珠日河沙化草地,研究燕麦(Avena sativa)种植在该地区氮肥的最佳用量,于苗期、分蘖期、拔节期、抽穗期4个时期施肥,分别占总施肥量的15%、40%、25%、20%。对燕麦追施0(CK)、70、140、210、280kg·hm~(-2)氮素,测定分蘖数、株高、茎粗、叶面积、生物量等生长指标及产量指标的变化。结果表明,追施70~280kg·hm-2氮肥均促进沙地燕麦地上部分的生长,其中以追施210kg·hm~(-2)氮肥效果最佳;追施70、140、210、280kg·hm~(-2)氮肥,沙地燕麦干草产量分别较N0增加56.96%(P0.05)、74.93%(P0.05)、121.32%(P0.05)、99.58%(P0.05)。因此,在内蒙古通辽市珠日河沙地种植燕麦追施氮肥的适宜用量为210kg·hm~(-2)。  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