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1.
A. Španová 《Folia microbiologica》1980,25(4):281-288
Temperature-sensitive (ts) mutations of the G101 phage were isolated after mutagenesis with hydroxylamine. A complementation analysis of 61ts mutants showed that these mutants may be divided into at least 12 complementation groups. Twots mutants probably originated in genes which control lytic functions of the G101 phage. It was shown by three factor crosses
that all of the 12ts mutations tested are localized on that side of the “c” region where the probablecI repressor gene is positioned. Sevents mutations is closely linked to thecI
26 clear marker, three exhibit a closer linkage and two do not exhibit any linkage withcI. All mutations isolated until now can be arrange linearly. According to the present knowledge the preliminary genetic map
of the G101 phage is linear. 相似文献
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H. Štorchová 《Biologia Plantarum》1994,36(3):358-358
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F. Šrámek 《Biologia Plantarum》1999,42(4):582-582
8.
Hana Votavová Vladimír Gut Karel Bláha Jaroslav Šponar 《International journal of biological macromolecules》1982,4(6):341-346
DNA complexes with polypeptides (Lys-Ala-Ala)1)] and (Lys-Ala-Ala)34 have been studied using the methods of thermal melting and circular dichroism. Derivative melting curves of (Lys-Ala-Ala)10 DNA differed substantially from those of (Lys-Ala-Ala)34 prepared either by salt gradient dialysis or by direct mixing. Melting curves of the former complex were unimodal or bimodal with Tm increasing continuously withn input lysin-to-DNA phosphate ratio (r); those of the latter complex consisted of three separate transitions with Tm values almost independent of r. Complete reversibility of binding in the (Lys-Ala-Ala)10-DNA system but a slow redistribution of (Lys-Ala-Ala)34 on DNA at low temperature were found in the redistribution experiments Much faster redistribution from denatured to native DNA occurs at the temperature of melting, contributing to the unusual trimodal melting pattern. Circular dichroism curves are very similar for both complexes and indicate little change of DNA conformation upon polypeptide binding. 相似文献
9.
Phylogenetic analyses of primate size evolution: the consequences of sexual selection 总被引:6,自引:0,他引:6
Patrik Lindenfors Birgitta S. Tullberg 《Biological journal of the Linnean Society. Linnean Society of London》1998,64(4):413-447
We have analysed the relationship between primate mating system, size and size dimorphism by utilizing several phylogenetically based methods. An independent contrast analysis of male and female size (log weight) showed that these are tightly correlated and that size dimorphism is not a simple allometric function of size. We found no relationship between mating system and sexual dimorphism in strepsirhines but a strong relationship in haplorhines. By matched-pairs analysis, where sister groups were matched according to whether the mating system predicted higher or lower intrasexual selection for male size, haplorhine species in more polygynous clades (with a predicted higher sexual selection) were significantly more dimorphic, had larger males, and also, but to a lesser degree, larger females. Both independent contrast and matched-pairs analyses are non-directional and correlational. By using a directional test we investigated how a transition in mating system affects size and dimorphism. Here, each observation is the sum of changes in dimorphism or size in a clade that is defined by a common origin of a mating system. Generally, dimorphism, as well as male and female size, increased after an expected increase in sexual selection, and decreased after an expected decrease in sexual selection. The pattern was, however, not significant for all of the alternative character reconstructions. In clades with an expected increase in sexual selection, male size increased more than female size. This pattern was significant for all character reconstructions. The directional investigation indicates that the magnitude of change in haplorhine dimorphism is larger after an increase in sexual selection than after a decrease, and, for some reconstructions, that the magnitude of size increase is larger than the magnitude of size decrease for both sexes. Possible reasons for these patterns are discussed, as well as their implications as being one possible mechanism behind Cope's rule, i.e. general size increase in many phylogenetic lineages. 相似文献
10.
Twelve metronidazole-resistant and twelve metronidazole-susceptible strains ofTrichomonas vaginalis were tested for the presence of dsRNA. Three resistant and five susceptible strains were found to contain dsRNA which indicated
that metronidazole resistance does not correlate with the absence of dsRNA. Electron microscopy showed the homogenates of
all dsRNA -positive strains to contain virus-like particles 32 –38 nm in diameter, while no such particles were found in the
dsRNA-negative strains. A mutual relationship between the dsRNA and virus-like particles seems to exist.
After this paper had been accepted for publication the occurrence of virus-like particles in dsRNA-positive trichomonads was
reported by others (Wang A.L., Wang C.C.: The double stranded RNA inTrichomonas vaginalis may originate from virus-like particles.Proc. Nat. Acad. Sci. USA
83, 7956–7961, 1986). 相似文献