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本研究采用大肠杆菌GM133 rifr细胞和营养收集细胞HB214 strr进行适应性突变实验。在混合30min和2d 后添加链霉素杀死GM133基因型细胞,继续培养5d后,在选择平板上出现了一定数量的lac+strr基因型回复突变菌落。根据这些突变菌落的数量,估计在lac+突变产生之前,GM133和HB214细胞之间的接合频率分别为0.07%和7.47%。在培养了7d的选择平板上添加含链霉素的M9选择培养基,2d 后也观察到大量发生lac+突变但没有形成肉眼可见菌落的营养收集细胞。此外,在lac+突变发生后,也有F因子从GM133细胞转移进入HB214细胞。这些事实表明,在FC40系统的适应性突变实验中发生了真正的F因子转移。
Abstract:The experiment of adaptive mutation was performed by using Escherichia coli GM133 rifr as test cells and HB214 strr as scavenger cells.Transfer frequency between GM133 and HB214 was estimated,based on the number of revertants appeared on the selective plates when GM133 were killed by addition of M9 selective medium containing 100μg/mL of streptomycin at different time.After 30 minutes the cells of GM133 and HB214 were mixed,the estimated transfer frequency was about 0.07%,and two days,7.47%.After selection of 7 days,some HB214 cells with F` factor from GM133 cells and lac+ mutation were observed,but these cells failed to form the colonies which can be seen by the naked-eye.It was demonstrated that actual F` factor transfer events from test cells GM133 to scavenger cells HB214 occurred during the selection. 相似文献
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M. Zandipour M. Khodarahmi E. Majidi SH. Ebrahim-nejad 《Archives Of Phytopathology And Plant Protection》2013,46(12):1459-1465
In order to investigate heritability and gene action for yellow rust resistance in wheat, a resistance yellow rust cultivar Aflak was crossed to susceptible cultivar Avocet‘s’. Parents, F1, F2 and F3 generations were cultured according to randomised complete block design with two replications in the research station of Gharakhil, Iran. Parents and other generations were inoculated with 70E0A+ race. Traits including severity and infection type were recorded and then coefficient of infection was calculated. For this trait, generations mean and variance analysis were performed and results showed that there were significant differences among generations for coefficient of infection. Results showed that in addition to additive and dominance effects, at least one kind of epistasis interaction (additive × additive) control this trait. Although additive and dominance effects control this trait, but with attention to generations variance analysis, the results showed that additive variance had important role to control this trait. 相似文献
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Alexei A Sharov Geppino Falco Yulan Piao Suresh Poosala Kevin G Becker Alan B Zonderman Dan L Longo David Schlessinger Minoru SH Ko 《BMC biology》2008,6(1):24
Background
The aging of reproductive organs is not only a major social issue, but of special interest in aging research. A long-standing view of 'immortal germ line versus mortal soma' poses an important question of whether the reproductive tissues age in similar ways to the somatic tissues. As a first step to understand this phenomenon, we examine global changes in gene expression patterns by DNA microarrays in ovaries and testes of C57BL/6 mice at 1, 6, 16, and 24 months of age. In addition, we compared a group of mice on ad libitum (AL) feeding with a group on lifespan-extending 40% calorie restriction (CR). 相似文献18.
Forbes SH; Hogg JT; Buchanan FC; Crawford AM; Allendorf FW 《Molecular biology and evolution》1995,12(6):1106-1113
We compared genotypes at eight (AC)n microsatellite loci in domestic sheep
(Ovis aries) and wild Rocky Mountain bighorn sheep (O. canadensis). The
domestic sheep had greater genetic variation, higher allele-size variances,
and larger allele sizes than the wild sheep. Accumulating evidence from
higher taxonomic comparisons shows that these parameters are biased if
microsatellite loci are selected in one taxon and used in another. Our
results demonstrate similar biases between congeneric species. We compared
standard measures of genetic variation, differentiation, and distance
within and between species (H, D, FST) to newer measures based on
allele-size variance (SW, SB, RST). The size-based distances better
detected species-level divergence, but standard measures better
distinguished allopatric populations. Empirical calibration of these
measures at the subspecies level is needed to establish their useful
ranges.
相似文献
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The distribution of flourescently labeled α-actinin after microinjection into fibroblasts has been determined in both living and fixed cells. We have found that the distribution of the injected tetramethylrhodamine isthiocyanate-labeled protein (TMRITC-α-actinin) in living cells, which is in ruffling membranes, actin microfilament bundles, and polygonal microfilament networks (Feramisco, 1979, Proc. Natl. Acad. Sci. U. S. A. 76:3967-3971), was virtually unaffected by the fixation (3.5 percent formaldehyde) and extraction (absolute acetone) used for the preparation of the cells for immunoflourescence. Also, these patterns were found to coincide with the α-actinin revealed by immunoflourescence. Also, these patterns were found to coincide with the α-actinin revealed by immunoflourescence. These findings offer, for the first time, evidence indicating the validity of the immunoflourescence technique in the localization of α-actinin in cultured cells. With the combination of the injection procedure and the immunoflourescence localization of endogenous structural proteins, it was determined that nearly all of the actin stress fibers were decorated in a periodic manner with the injected α-actinin. Endogenous tropomyosin in the injected cells was found to be distributed with a periodic pattern along the stress fibers that was antiperiodic to the pattern observed for the microinjected α-actinin. The tropomyosin antibody stained the polygonal microfilament networks and was excluded from the foci, whereas the microinjected α-actinin was incorporated into the foci of the networks. Thus, the microinjected fluorescent derivative of α-actinin appears to be incorporated into the functional pools of α-actinin within the living cell and to be utilized by the cell with fidelity. 相似文献
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We determined the cellular localization of an endogenous lectin at various times during the development of a well-characterized region of chick brain, the optic tectum. This lectin is a carbohydrate-binding protein that interacts with lactose and other saccharides, undergoes striking changes in specific activity with development, and has previously been purified by affinity chromatography from extracts of embryonic chick brain and muscle. Cellular localization in the tectum was done by indirect immunofluoresecent staining, using immunoglobulin G derived from an antiserum raised against pure lectin. No lectin was detectable in the optic tectum examined at 5 days of embryonic development. From approximately 7 days of development, neuronal cell bodies and fibers were labeled by the antibody; and extracts of tectum contained hemagglutination activity that could be inhibited by lactose or by the antiserum. Lectin remained present in many tectal neuronal layers after hatching; but in 2-month-old chicks it was sparse or absent in most of the tectum except for prominent labeling of fibers in the stratum album centrale. The initial appearance of lectin in the optic tectum was not dependent on innervation by optic nerve fibers since bilateral enucleation during embryogenesis did not affect it. Lectin was detectable on the surface of embryonic optic tectal neurons dissociated with a buffer containing EDTA. 相似文献