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51.
Geok -Yong Tan Wai -Koon Tan 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,80(2):258-264
Summary Quantitative inheritance of resistance to Phytophthora pod rot (Ppr) was studied in cocoa hybrid progeny from 12 Trinitario x Amazonian crosses and their reciprocal crosses. The crossing scheme was similar to a factorial design. Disease was assessed by the number and percentage of infected pods on each tree. Highly significant differences due to general combining abilities (GCA) were obtained for all characters, except for the GCA of Trinitario on total pod production. Differences for specific combining ability (SCA) were not significant for all characters. There were no significant differences between reciprocal crosses. The Trinitario clone K82 provided the only source for the hybrid progenies of strong Ppr resistance to the hybrid progenies, while K20 provided moderate resistance. Other parental clones — KA2-101, KA5-201, KEE 2, KEE 5, and KEE 52 — produced progenies which were susceptible to Ppr. It is evident that resistance to Ppr in cocoa is inherited additively. Maternal and cytoplasmic effects were assumed to have no influence on inheritance of resistance. It is also concluded that resistance to Ppr of the kind shown by K82 is likely to be horizontal resistance. Breeding for high-yielding cultivars combined with Ppr resistance is the most effective way of controlling Ppr of cocoa on the crops of growers with small holdings in Papua New Guinea. 相似文献
52.
To determine the main causes of death in "owl monkeys" (Aotus nancymae and A. vociferans) in captivity, 115 necropsies were performed. According to the macroscopic findings and clinical data, results are as follow: acute lobular pneumonia (25.2%), chronic nephropathy (10.4%), acute catarrhal enteritis (8.7%), acute hemorrhagic enteritis (7%), acute toxic hepatitis (5.2%), trauma (5.2%), and others. 相似文献
53.
Shlomo Nir Nejat Düzgünes Maria C. Pedroso De Lima Dick Hoekstra 《Cell biochemistry and biophysics》1990,17(2):181-201
The fusion of viruses with cells and liposomes is reviewed with focus on the analysis of the final extents and kinetics of
fusion.Influenza virus andSendai virus exhibit 100% of fusion capacity with cells at pH 5 and pH 7.5, respectively. On the other hand, there may be in certain
cases, a limit on the number of virions that can fuse with a single cell, that is significantly below the limit on binding.
It still remains to be resolved whether this limit reflects a limited number of possible fusion sites, or a saturation limit
on the amount of viral glycoproteins that can be incorporated in the cellular membrane, like the case of virus fusion with
pure phospholipid vesicles, in which the fusion products were shown to consist of a single virus and several liposomes. Both
viruses demonstrate incomplete fusion activity towards liposomes of a variety of compositions. In the case ofSendai virus, fusion inactive virions bind essentially irreversibly to liposomes. Yet, preliminary results revealed that such bound,
unfused virions can be released by sucrose gradient centrifugation. The separated unfused virions subsequently fuse when incubated
with a “fresh” batch of liposomes. We conclude, therefore, that the fraction of initially bound unfused virions does not consist
of dective particles, but rather of particles bound to liposomes via “inactive” sites.
Details of the low pH inactivation of fusion capacity ofinfluenza virus towards cells and liposomes are presented. This inactivation is caused by protonation and exposure of the hydrophobic
segment of HA2, and affects primarily the fusion rate constants. Some degree of inactivation also occurs when virions are bound to cellular
membranes. 相似文献
54.
B. J. Steffenson P. M. Hayes A. Kleinhofs 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(5):552-558
Net blotch (caused by Pyrenophora teres f. teres) and spot blotch (Cochliobolus sativus) are important foliar diseases of barley in the midwestern region of the USA. To determine the number and chromosomal location of Mendelian and quantitative trait loci (QTL) controlling resistance to these diseases, a doubled haploid population (Steptoe/Morex) was evaluated to the pathogens at the seedling stage in the greenhouse and at the adult plant stage in the field. Alleles at two or three unlinked loci were found to confer resistance to the net blotch pathogen at the seedling stage depending on how progeny exhibiting an intermediate infection response were classified. This result was corroborated in the quantitative analysis of the raw infection response data as 2 major QTL were identified on chromosomes 4 and 6M. A third QTL was also identified on chromosome 6P. Seven QTL were identified for net blotch resistance at the adult plant stage and mapped to chromosomes 1P, 2P, 3P, 3M, 4, 6P, and 7P. The 7 QTL collectively accounted for 67.6% of the phenotypic variance under a multiple QTL model. Resistance to the spot blotch pathogen was conferred by a single gene at the seedling stage. This gene was mapped to the distal region of chromosome 1P on the basis of both qualitative and quantitative data analyses. Two QTL were identified for spot blotch resistance at the adult plant stage: the largest QTL effect mapped to chromosome 5P and the other mapped to chromosome 1P near the seedling resistance locus. Together, the 2 QTL explained 70.1% of the phenotypic variance under a multiple QTL model. On the basis of the chromosomal locations of resistance alleles detected in this study, it should be feasible to combine high levels of resistance to both P. teres f. teres and C. sativus in barley cultivars. 相似文献
55.
K. B. Singh M. V. Reddy 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(5):509-515
Ascochyta blight [Ascochyta rabiei (Pass.) Lab.] is the most destructive disease of chickpea (Cicer arietinum L.), but it can be managed effectively by the use of resistant cultivars. Therefore, a breeding programme was initiated during 1977–78 at ICARDA, Syria, to breed blight-resistant, high-yielding chickpeas with other desirable agronomic traits. Crosses were made in main season at Tel Hadya, Syria, and the F1s were grown in the off season at Terbol, Lebanon. The F2, F4 and F5 generations were grown in a blight nursery in the main season where blight epidemic was artificially created. The plants and progenies were scored for blight resistance and other traits. The F3 and F6 generations were grown in the off season under normal day length to eliminate late-maturing plants. The pedigree method of breeding was followed initially, but was later replaced by the F4-derived family method. The yield assessment began with F7 lines, first at ICARDA sites and later internationally. A total of 1584 ascochyta blight-resistant chickpea lines were developed with a range of maturity, plant height, and seed size not previously available to growers in the blight-endemic areas in the Mediterranean region. These included 92 lines resistant to six races of the ascochyta pathogen, and 15 large-seeded and 28 early maturity lines. New cultivars produced 33% more seed yield than the original resistant sources. The yield of chickpea declined by 340 kg ha-1, with an increase in blight severity by one class on a 1–9 scale, reaching zero yield with the 8 and 9 classes. Development of blight-resistant lines made the introduction of winter sowing possible in the Mediterranean region with the prospect of doubling chickpea production. Twenty three cultivars have been released so far in 11 countries.Joint contribution from ICARDA and ICRISAT. ICRISAT Journal Article no. JA 1886. 相似文献
56.
Markers for selection of the rice Xa21 disease resistance gene 总被引:8,自引:0,他引:8
C. E. Williams B. Wang T. E. Holsten J. Scambray F. de Assis Goes da Silva P. C. Ronald 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(7):1119-1122
Six molecular markers were mapped to a 7.4-cM region of rice chromosome 11 containing the Xa21 gene, which confers resistance to the pathogen Xanthomonas oryzae pv oryzae. Three markers, RG103, 248 and 818, co-segregated with Xa21 in a population of 1141 plants. Multiple copies of all marker loci were present within the region that was introgressed from Oryza longistaminata into O. sativa. The marker loci were cloned and primers were designed that defined sequence-tagged sites. Physical mapping of the three tightly linked central markers revealed that RG103, the marker that hybridizes to the Xa21 gene, resides on a separate DNA fragment from the other two markers.Disclaimer: Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable. 相似文献
57.
Synthesis of methyl
-Ribose was converted into methyl
and this, on tin-mediated allylation, gave a mixture of the 2-O-allyl and 3-O-allyl derivatives which were separated by chromatography. The more polar isomer was characterised as the 3-O-allyl derivative after conversion via
(which was also synthesised from
) into the known
. Methyl
was converted into methyl
via methyl
. 相似文献
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59.
用抗单纯疱疹病毒(HSV)型共同性gC和gD羊克隆抗体(McAb),包被即Eppendorf管,捕捉HSV,同时加入3个引物:一个是HSV─1/HSV─2型共同性上游引物,另两个分别是HSV─1和HSV─2型特异性下游引物。借此建立了能直接分型检测HSV的抗原捕获聚合酶链式反应(AC─PCR)。HSV─1的扩增产物为477bp,HSV─2的为399bp两型病毒经AC─PCR扩增后产生分子量不同的DNA片段,致使AC─PCR能直接分型检测HSV。HSV─1和HSV─2扩增产物的克隆和序列分析表明,本方法特异性好。用本法检测Balb/c幼鼠中枢神经系统HSV感染的脑标本,进一步证实本方法不仅敏感、特异,而且分型准确。 相似文献
60.
丙型肝炎病毒基因组部份NS5区蛋白基因在大肠杆菌中的表达 总被引:1,自引:0,他引:1
在大肠杆菌中表达了丙型肝炎病毒基因组NS5区A段和部份B段蛋白。NS5A蛋白溶于水,可经过GST亲和层析柱纯化;NS5B蛋白不溶于水,经PBS-Triton X-100洗涤,尿素溶解后,通过离子交换柱纯化。经SDS-PAGE和Westemblot分析,NS5A蛋白除在57kD左右有条带外,还有不同程度的降解产物;NS5B蛋白主要在58kD左右有条带出现。为查明表达蛋白抗体在病人血清中的分布,取9 相似文献