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901.
The athermal bioeffects caused by nanosecond electromagnetic pulses with body cells was studied by using a broad band transverse EM-wave cell (BTEM CELL). The experimental system and preliminary mechanism analysis were presented. 相似文献
902.
YANG Jianbo WU Lijun LI Li WU JiadaoYU Zengliang XU Zhihong 《中国科学:生命科学英文版》1997,40(1):107-112
While M13mp18 double-stranded DNA was irradiated with ion beam, and transfected intoE. coli JM103, a decrease of transfecting activity was discovered. The lacZ- mutation frequency at 20% survival could reach (3.6–16.8) × 104, about 2, 3–10 times that of unirradiated M13DNA. Altogether, 27 IacZ-mutants were selected, 10 of which were used for sequencing. 7 of the sequenced mutants show base changes in 250-bp region
examined (the remaining 3 mutants probably have base changes outside the regions sequenced). 5 of the base-changed mutants
contain more than one mutational base sites (some of them even have 5–6 mutational base sites in 250-bp region examined);
this dense distribution of base changes in polysites has seldom been seen in X-rays, Y-rays or UV induced DNA mutations. Our
experiments also showed that the types of base changes include transitions(50%), transversions (45%) and deletion (5%); no
addition or duplication was observed. The transitions were mainly C→T and A→G; the transversions were mainly C→A and C→G.
The mutations involving cytosine residue (in the template strand) constitute about 60% of all the base changes observed. In
comparison with the surrounding sequences of mutational base sites, the base located between TG and CT is found to be easily
substituted. 相似文献
903.
Sequence variation and genetic diversity in the giant panda 总被引:3,自引:0,他引:3
ZHANG YapingOliver A. RyderFAN Zhiyong ZHANG HemingHE TingmeiHE Guangxin ZHANG Anju FEI LisongZHONG Shunlong CHEN HongZHANG Chenglin YANG Minghai ZHU Feibing PENG Zhenxin PU Tianchun CHEN Yucun YAO OMinda GUO Wei 《中国科学:生命科学英文版》1997,40(2):210-216
About 336–444 bp mitochondrial D-loop region and tRNA gene were sequenced for 40 individuals of the giant panda which were
collected from Mabian, Meigu, Yuexi, Baoxing, Pingwu, Qingchuan, Nanping and Baishuijiang, respectively. 9 haplotypes were
found in 21 founders. The results showed that the giant panda has low genetic variations, and that there is no notable genetic
isolation among geographical populations. The ancestor of the living giant panda population perhaps appeared in the late Pleistocene,
and unfortunately, might have suffered bottleneck attacks. Afterwards, its genetic diversity seemed to recover to some extent.
Project supported by the “8.5” Key Project of Chinese Academy of Sciences, the Chairman Foundation of Chinese Academy of Sciences,
K. C. Wang Education Foundation, the Applied Basic Research Foundation of Yunnan, the National Natural Science Foundation
of China, the Special Foundation for Returned Chinese Scientists, and Zoological Society of San Diego. 相似文献
904.
Path-coefficient analyses and genetic parameters of the components of field resistance of potatoes to late blight 总被引:4,自引:0,他引:4
Variation, genetic parameters, interrelationships and phenotypic and genetic path analyses for components of field resistance of potatoes to Phytophthora infestuns were studied using detached leaves from 16 potato cultivars. Inter-genotypic variability was significant for the components and the Area Under Disease Progress Curve (AUDPC). The resistant cultivars generally had a longer latent period and lower lesion size and spore production than the susceptible cultivars. The correlations between AUDPC and infection efficiency, and between AUDPC and spore density were not significant, but latent period, lesion size and sporulation did correlate significantly with AUDPC. Genetic and phenotypic path-coefficient analyses indicated lesion size to be the most important component of field resistance. The genetic correlation coefficients between the AUDPC and infection efficiency, latent period and spore density arose mainly because of their indirect effects on AUDPC via lesion size. Lesion size and AUDPC had a high genetic coefficient of variation, heritability and genetic advance (genetic gain). 相似文献
905.
906.
Joseph A. Ezzo Clark Spencer Larsen James H. Burton 《American journal of physical anthropology》1995,98(4):471-481
Multielement analysis was performed on bone samples extracted from the femora of 39 adults from three mortuary sites (Johns Mound, Santa Catalina de Guale, and Santa Catalina de Guale de Santa Meria) and time periods (late preagricultural, early contact, and late contact) in the Georgia Bight. This study was used to investigate whether elemental analysis would support or contradict other lines of data regarding diets and dietary change previously generated for the region. The data are in agreement with an earlier interpretation, based on stable isotopes, that dietary maize increases through time but fails to support the idea that marine resources decreased in importance. Rather, it appears that the wild plant food component of the diets decreases as maize increases in importance; throughout the sequence, marine resources comprise a significant portion of the diets. © 1995 Wiley-Liss, Inc. 相似文献
907.
Intergeneric hybridizations were made betweenT. elongatum, and twoPsathyrostachys and fiveLeymus species. The seed set obtained onT. elongatum ×Leymus hybrids ranged from 5.65% to 20.00%, depending onLeymus species. The seed set obtained onT. elongatum ×Psathyrostachys hybrids ranged from 16.07% to 19.70%. Meiotic pairing at metaphase-I in JN diploid hybrids ofT. elongatum ×Psathyrostachys species revealed a very low level homology between the basic J and N genomes, and further demonstrated that the two genomes are quite diverged. Chromosome pairing in theT. elongatum ×Leymus secalinus hybrid averaged 15.19 univalents + 2.62 rod bivalents + 0.26 ring bivalents + 0.02 trivalents, suggesting that the partial Je chromosomes ofT. elongatum has homology withLeymus secalinus genomes.L. secalinus might have 3–4 chromosomes originating from Je genome. 相似文献
908.
Bricchi Emma Frenguelli Giuseppe Mincigrucci Gianfranco Fornaciari Marco Ferranti Francesco Romano Bruno 《Aerobiologia》1995,11(1):57-61
Times of pollination of different taxa in the atmosphere of Perugia (Central Italy) over an 11-year period (1982–1992) were recorded and analysed by means of a 7-day volumetric Hirst-type pollen trap. For some taxa, the pollination period varied from year to year from a chronological and/or quantitative point of view. Several taxa showed a linkage in their starting dates of pollination. Knowledge of this kind of linkage allows us to build a forecasting model. 相似文献
909.
Kohei Murata Masato Sakon Jun-ichi Kambayashi Masaki Okuyama Toshiharu Hase Takesada Mori 《Journal of cellular biochemistry》1995,57(1):120-126
Calyculin A and okadaic acid, potent and cell permeable inhibitors of type 1 and type 2A protein phosphatases, inhibit platelet aggregation and secretion. However, the relationship between phosphatase inhibition and inhibition of platelet function is not well understood. We found that in unstimulated platelets, talin (P235) was phosphorylated at threonine residues by calyculin A. Furthermore, the extent of talin phosphorylation by calyculin A was closely correlated with its inhibition of thrombin-induced platelet aggregation. Since the binding of talin to platelet glycoprotein IIb/IIIa complex has been shown to be affected by its phosphorylation, these results suggest that type 1 and/or type 2A protein phosphatases may play a role in the regulation of membrane-cytoskeleton interaction through dephosphorylation of talin. 相似文献
910.