水稻品种抗瘟性诱导研究Ⅰ.非生物诱导物的筛选及诱导方法初探   总被引：8，自引：0，他引：8  

王国平  罗宽 《植物病理学报》1994,24(2):123-126

 采用经反复筛选的化学药剂亚硒酸钠、放线菌酮、氯化钾、硫酸锰和中药材前胡、白芷的提取液浸泡水稻种子或进行叶面喷雾,可诱导稻株产生对稻瘟病的抗性。在人工喷雾接种条件下,对感病品种抗叶瘟的诱导效果为43%~93%;在注射接种条件下,抗穗瘟的诱导效果为29%~78%。供试药剂对感病品种和弱致病菌株的诱导效果优于对抗病品种和强致病菌株;药液叶面喷雾的诱导效果优于药液浸种。  相似文献   

秦川牛近交与近交衰退的分析     

王金良  杜建昌 《中国牛业科学》1992,18(1):10-14

本文分析了陕西省秦川牛场秦川牛群近交及其对初生重、断奶重及哺乳期成活率的影响,并采用标准群体遗传学模型分析了秦川牛的致死当量。研究发现,30多年来秦川牛群平均近交系数呈明显的上升趋势,而且近交对成活率、初生重及断奶重均有一定危害;秦川牛群体的隐性有害基因含量较少,平均每个个体约携带2.05个致死当量。  相似文献   

Relationship of common avian pathogen antibody titers in so-called chicken anemia agent (CAA)-antibody-positive chicks to titers in CAA-antibody-negative chicks.     

M A Goodwin  J Brown  M A Smeltzer  T Girshick  S L Miller  T G Dickson 《Avian diseases》1992,36(2):356-358

Antibody titers for infectious bursal disease virus (IBDV), infectious bronchitis virus, Newcastle disease virus, and reovirus from chicks with chicken anemia agent (CAA) antibodies were compared with antibody titers from their CAA-antibody-negative counterparts. These comparisons were made in 396 chickens that were 1 day, 2 weeks, 8-9 weeks, 10 weeks, 17 weeks, or 29-32 weeks old. Only one serum sample was collected from any given chick or chicken. There were no significant differences between the antibody titers at any age for any antigen, with one exception: at 29-32 weeks, the IBDV titers were higher (t = 2.62, df = 142, P less than 0.01) in chickens with CAA antibody. Although not at all likely, we believe that the observation of high IBDV antibody titers in CAA-antibody-positive chicks could have been a spurious one.  相似文献   

Monoclonal antibodies to bovine viral diarrhea virus: cross-reactivities to field isolates and hog cholera virus strains.   总被引：2，自引：1，他引：1       下载免费PDF全文

D Deregt  S R Bolin  R A Heckert    K G Loewen 《Canadian journal of veterinary research》1994,58(1):71-74

Monoclonal antibodies to bovine viral diarrhea virus (BVDV) were examined for binding with a large number of North American BVDV isolates and eight strains of the serologically related pestivirus, hog cholera virus (HCV). No single BVDV monoclonal antibody reacted with all BVDV isolates. The most cross-reactive monoclonal antibody was an anti-p80/p125 antibody which showed a positive reaction with 173 of 180 (96%) North American isolates. From a fewer number of isolates tested, one anti-gp53 monoclonal antibody also showed a high cross-reactivity (94%). All BVDV isolates showed a positive reaction with at least one of the seven monoclonal antibodies in the panel. Thus, the results indicated that a pool of these monoclonal antibodies may be used in place of polyclonal antisera for the detection of BVDV contamination of cell lines or for virus isolation. For HCV, all three anti-p80/p125 monoclonal antibodies reacted positively with all eight virus strains. In contrast, none of the anti-gp53 monoclonal antibodies were reactive to HCV strains. Thus, the anti-gp53 monoclonal antibodies may be useful for distinguishing between usually innocuous BVDV infections and the highly significant HCV infections in swine for foreign animal disease surveillance.  相似文献   

COMPUTED TOMOGRAPHY-GUIDED PERCUTANEOUS BIOPSY: CRITERIA FOR ACCURATE NEEDLE TIP IDENTIFICATION     

Amy S.  Tidwell  DVM  Karen L.  Johnson  BS  CNMT 《Veterinary radiology & ultrasound》1994,35(6):440-444

Precise localization of the needle tip during CT-guided percutaneous biopsy is considered to be a key element of a successful procedure. To ensure accuracy, the true needle tip must be differentiated from a false or simulated tip which appears when the CT slice encompasses only the shaft of an angled needle. By obtaining images of an aspiration biopsy needle inserted vertically into a phantom and then incrementally tilting the gantry, the authors were able to compare the characteristic features of the true tip to the simulated tip. The true tip was abrupt and distinct and had an adjacent flame-like low density artifact. The simulated tip was indistinct and tapered, yet still produced the adjacent artifact. We concluded that the shape and distinctness of the end portion of the needle itself, rather than the attendant artifact, were the most reliable criteria for accurate needle tip identification.  相似文献   

5-bromo-2'-deoxyuridine blocks myogenesis by extinguishing expression of MyoD1   总被引：16，自引：0，他引：16  

S J Tapscott  A B Lassar  R L Davis  H Weintraub 《Science (New York, N.Y.)》1989,245(4917):532-536

The pyrimidine analog 5-bromodeoxyuridine (BUdR) competes with thymidine for incorporation into DNA. Substitution of BUdR for thymidine does not significantly affect cell viability but does block cell differentiation in many different lineages. BUdR substitution in a mouse myoblast line blocked myogenic differentiation and extinguished the expression of the myogenic determination gene MyoD1. Forced expression of MyoD1 from a transfected expression vector in a BUdR-substituted myoblast overcame the block to differentiation imposed by BUdR. Activation of BUdR-substituted muscle structural genes and apparently normal differentiation were observed in transfected myoblasts. This shows that BUdR blocks myogenesis at the level of a myogenic regulatory gene, possibly MyoD1, not by directly inhibiting the activation of muscle structural genes. It is consistent with the idea that BUdR selectively blocks a class of regulatory genes, each member of which is important for the development of a different cell lineage.  相似文献   

高维Mbius变换的类型判别法     

王仙桃 《湖南农业大学学报(自然科学版)》1992,19(3)

本文利用高维Mbius变换的直角坐标表示式,找到了它们Poincaré扩张的具体式子,并研究了任意有限维不同类型的Mǒbius变换的系数的一些性质及不动点的位置,在此基础上建立了高维Mbius变换只依赖于系数的判别法.  相似文献   

Trenbolone acetate/estradiol combinations in feedlot steers: dose-response and implant carrier effects.     

S J Bartle  R L Preston  R E Brown  R J Grant 《Journal of animal science》1992,70(5):1326-1332

Two experiments were conducted at three locations to determine the correct dosage and carrier for trenbolone acetate (TBA) and estradiol (E2) implants in feedlot steers. In the dose-response experiment, 1,296 steers were allotted to six implant treatments (48 pens per location): control, 140 mg of TBA (140/0), 30 mg of E2 (0/30), 20 mg of TBA + 4 mg of E2(20/4), 80 mg of TBA + 16 mg of E2(80/16), and 140 mg of TBA + 28 mg of E2 (140/28). In the carrier experiment, 575 steers were allotted to five implant treatments (25 pens per location): control, 140 mg of TBA + 28 mg of E2 in lactose (140/28-LA), 140 mg of TBA + 28 mg of E2 in cholesterol (140/28-CH), 140 mg of TBA + 20 mg of E2 in LA (140/20-LA), and 200 mg of progesterone + 20 mg of E2 benzoate (SS, reimplanted). In both experiments steers were fed a finishing diet for 140 to 168 d. In the dose-response experiment, response to TBA alone (140/0) did not differ from control (P greater than .2). Estradiol alone (0/30) improved ADG by 7% (P less than .01) and tended to improve feed efficiency over control (3%, P = .17). The highest dosage (140/28) improved ADG by 18% (P less than .001) and feed efficiency by 10% (P less than .001) over control and 10% (P less than .001) and 7% (P less than .01) over E2 alone, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

西农萨能奶山羊血浆生长激素水平的变化及其与奶产量的关系   总被引：1，自引：0，他引：1  

尤秋梅  王建元 《畜牧兽医学报》1992,23(2):118-123

本实验用放免测定法(RIA)测定了38只西农萨能奶山羊(其中360～450日龄的青年羊10只,产前一月至产后90天的头胎和2胎羊各14只)血浆GH水平变化,分析了血浆GH水平与奶量的相关性。结果表明:360～450日龄的青年羊血浆GH维持在一个波动较小的范围(20.37±5.17～23.13±5.97ng/ml),头胎羊和二胎羊分娩前后及泌乳早期血浆GH水平的变化趋势相一致,在同一生理状态下,二胎羊血浆GH水平都显著地高于头胎羊。相关分析还表明:头胎羊和二胎羊血浆GH水平都与其奶量呈直线正相关关系(P<0.05)。综上结果可以认为,奶山羊血浆GN水平可作为选育高产奶山羊的一项指标。  相似文献   

Humoral recognition of lipopolysaccharide core antigens of gram-negative bacteria in neonatal swine     

J W Tyler  J S Cullor  M C Thurmond  D W Hird  K M Parker 《American journal of veterinary research》1989,50(1):126-130

Serologic recognition of common lipopolysaccharide core antigens has been related to enhanced resistance to gram-negative bacterial disease in several species. Class-specific titers (IgG, IgM) were determined by direct ELISA, using intact Escherichia coli (J5) as a plate antigen. Serum samples were obtained from 224 neonatal swine between the ages of 36 and 60 hours. The mean (+/- SEM) log10 IgG titer against gram-negative core antigens was 1:1,713 +/- 0.4718 and the mean log10 IgM titer was 1:202 +/- 0.5644. The IgG titer was directly related with litter size, birth weight, and serum total IgG concentration; IgM titer was directly related with dam parity and serum total IgG concentration.  相似文献