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91.
92.
N C Kan 《Avian diseases》1991,35(4):941-949
Avian carcinoma retrovirus MH2 induces leukemia and solid tumors in chickens and transforms fibroblasts and macrophages in vitro. The genome of MH2 consists of two oncogenes, v-mht/mil and v-myc. Most of the transforming activity of MH2 is attributed to the v-myc oncogene. In contrast, the v-mht/mil oncogene alone does not induce a fully transformed phenotype of avian primary fibroblasts in vitro. It was shown previously that v-mht/mil is the avian homology of the v-raf oncogene in murine sarcoma retrovirus 3611. Because the v-raf oncogene transforms murine fibroblasts very efficiently, the present study tested the hypothesis that an extra segment in the 5' end of v-mht/mil relative to v-raf suppressed the fibroblast-transforming activity of v-mht/mil. By introducing an in-frame deletion of 195 nucleotides into the 5' end of v-mht/mil, the results demonstrate that in the presence of an inactive v-myc oncogene, the 5'-deleted v-mht/mil oncogene fails to transform chicken embryo fibroblasts. Therefore, it is likely that avian primary fibroblasts lack a cellular component that serves as a critical substrate/target for v-mht/mil-induced cellular transformation. 相似文献
93.
94.
S Sato K Ogimoto Y Nakai 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1990,52(4):719-725
Distribution of immunoglobulin(Ig)-containing cells was investigated in calves inoculated orally with live organisms of both Bacteroides succinogenes and Selenomonas ruminantium. Pathological changes and many Ig-containing cells were observed in calves which inoculated three times at 2, 3 and 26 days of age. Follicular germinal center was increased in number and size of the lymph nodes associated with the forestomach, suggesting activation of lymph apparatus. In the associated lymph nodes, IgG-containing cells were predominant and were located in both cortex and medulla, mainly in the medullary cord, B lymphocyte areas. Only a few IgA- and IgM-containing cells were observed in the lymph nodes. Accordingly, the inoculated bacteria may stimulate IgG-containing B lymphocyte populations. A few IgG-containing cells were detected in the mucosa of the forestomach. Ig-containing cells, predominantly IgG, were observed in the mucosa of the abomasum and intestine, and in the mesenteric lymph nodes. However, number of the cells in the mesenteric lymph nodes was smaller than that of the forestomach associated lymph nodes. The results suggest that the intraorally inoculated bacteria may stimulate the maturation of IgG positive lymphocytes in the lymph nodes associated with the forestomach. 相似文献
95.
介绍了食品生产、流通以及消费过程中存在的导致食品不安全的因素,论述了食品安全问题的重要性和特殊性,针对这些问题提出了解决食品安全的对策建议. 相似文献
96.
97.
The repeated elements called phytomers, which consist of leaf, node, internode and axillary bud, play an important role in
the development of modular organization in plants. Rice has the striking feature that the rate of the phytomer production
is closely synchronized with the rate of leaf emergence (phyllochron). We examined developmental changes of phyllochron by
using 10 near-isogenic lines (NILs) showing diversified growth durations in rice. The NILs were established by backcrosses
with a strain practically insensitive to photoperiod, and they consisted of early- or late-flowering NILs whose differences
of growth duration were caused by the combinations of alleles at 6 loci. The developmental patterns of phyllochron were evaluated
by means of a quartic polynomial, which fitted well in most cases. The results indicated that phyllochron greatly changed
during development, especially in late-flowering NILs as well as the recurrent parents, although the fluctuation of phyllochron
was not so marked in the early-flowering NILs. Thus, the developmental change of phyllochron was highly dependent upon the
genotypes and/or growth duration; however, it was associated with neither floral initiation nor temperature, indicating that
the change of phyllochron might reflect internal or physiological changes which occur during the life cycle of rice.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
98.
Summary Ninety Chinese rice landraces were examined with special reference to the indica-japonica differentiation in terms of traditional criteria, isozyme analysis and PCR analysis of the chloroplast DNA (cpDNA). Cultivars were separated into indica and japonica defined by a discriminant function (Z) based on key characters, as well as by isozyme genotypes. Most indica landraces had chloroplast DNAs with a deletion at the Pst-12 fragment, while most japonica landraces had cpDNAs without the deletion. Two traditionally recognized varietal groups in China, keng and hsien, corresponded largely to the respective japonica and indica revealed in our study. The results obtained in this study showed good agreement for classification of indica and japonica types by the three methods: discriminant analysis by Z value, isozyme analysis, and PCR analysis for cpDNA. 相似文献
99.
Zhengjun Xia Hiroko Sato Satoshi Watanabe Shiji Kawasaki Kyuya Harada 《Euphytica》2005,141(1-2):129-137
We have constructed a soybean (Glycine max (L.) Merrill) bacterial artificial chromosome (BAC) library from green leaf protoplasts of the cultivar, Misuzudaizu. The library contains 53,760 clones with an average insert size of 116 kb. About 2.9% chloroplast DNA origin was revealed by PCR and colony hybridization. Apart from 2.8% clones having no insert, this library represents 5.2 genome equivalents. With this genome coverage, the probability of having any DNA sequence represented in the library is higher than 99.5%. Three-dimensional pools of the BAC library in combination with the use of a high efficiency genome scanning (HEGS) electrophoresis facilitate rapid and efficient PCR-based screening. An average of five positive clones were identified after screening the BAC library with SSR and STS markers. BAC-end walking was performed for three SSR associated BACs. This library will provide a good resource for positional cloning of agronomically and biologically important QTL genes that Misuzudaizu possesses. 相似文献
100.
Deep-seeding tolerance, the emergence of seedlings from deep seeded conditions, is involved in stand establishment in semi-arid
regions, where the soil surface is too dry for seed germination. Genes determining deep-seeding tolerance in barley were mapped
using two doubled haploid populations derived from the following crosses: Harrington × TR306 (H/T)and Step toe × Morex (S/M).
Significant quantitative trait loci (QTLs) for deep-seeding tolerance were found in each population. Two QTL sex plained 40%
of the phenotypic variation in the H/T population and one QTL (S/M) 8% of the total phenotypic variance. Multiple QTLs accounting
for coleoptile length and first internode length were detected in both populations. In the H/T population, there were coincident
QTLs for deep-seeding tolerance, coleoptile length and first internode length on the long arm of chromosome 5H. These QTLs
correspond with previously reported QTLs for abscisic acid and gibberellic acid response. QTL coincidence may be due to the
pleiotropic effects of alleles at a single locus. This information may be useful for breeding programs manipulating morphological
and physiological traits in order to develop varieties for semi-arid regions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献