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991.
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Interactions between two catalytically distinct MCM subgroups are essential for coordinated ATP hydrolysis and DNA replication. 总被引:9,自引:0,他引:9
The six MCM (minichromosome maintenance) proteins are essential DNA replication factors that each contain a putative ATP binding motif and together form a heterohexameric complex. We show that these motifs are required for viability in vivo and coordinated ATP hydrolysis in vitro. Mutational analysis discriminates between two functionally distinct MCM protein subgroups: Mcm4p, 6p, and 7p contribute canonical ATP binding motifs essential for catalysis, whereas the related motifs in Mcm2p, 3p, and 5p serve a regulatory function. Reconstitution experiments indicate that specific functional interactions between these two subgroups are required for robust ATP hydrolysis. Our observations show parallels between the MCM complex and the F1-ATPase, and we discuss how ATP hydrolysis by the MCM complex might be coupled to DNA strand separation. 相似文献
995.
Brunner RM Srikanchai T Murani E Wimmers K Ponsuksili S 《Molecular biology reports》2012,39(1):97-107
Six genes that were known to exhibit expression levels that are correlated to drip loss BVES, SLC3A2, ZDHHC5, CS, COQ9, and
EGFR have been for candidate gene analysis. Based on in silico analysis SNPs were detected, confirmed by sequencing, and used for genotyping. The SNPs were genotyped in about 1,800 animals
from six pig populations including commercial herds of Pietrain (PI) and German Landrace (DL), different commercial herds
of Pietrain × (German Large White × German Landrace) (PIF1(a/b/c)), and one experimental F2-population Duroc × Pietrain (DUPI). Comparative and genetic mapping established the location of BVES on SSC1, of SLC3A2 and
ZDHHC5 on SSC2, of CS on SSC5, of COQ9 on SSC6 and of EGFR on SSC9, respectively, coinciding with QTL regions for carcass
and meat quality traits. BVES, SLC3A2, and CS revealed association at least with drip loss and with several other measures
of water holding capacity (WHC). Moreover, COQ9 and EGFR were associated with several meat quality traits such as meat color
and/or thawing loss. This study reveals statistic evidence in addition to the functional relationship of these genes to WHC
previously evidenced by expression analysis. This study reveals positional and genetic statistical evidence for a link of
genetic variation at these loci or close to them and promotes those six candidate genes as functional and/or positional candidate
genes for meat quality traits. 相似文献
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997.
Little is known regarding the role of androgenic hormones in the maintenance of myosin heavy chain (MHC) composition of rodent masticatory muscles. Because the masseter is the principal jaw closer in rodents, we felt it was important to characterize the influence of androgenic hormones on the MHC composition of the masseter. To determine the extent of sexual dimorphism in the phenotype of masseter muscle fibers of adult (10-mo-old) C57 mice, we stained tissue sections with antibodies specific to type IIa and IIb MHC isoforms. Females contain twice as many fibers containing the IIa MHC as males, and males contain twice as many fibers containing the IIb MHC as females. There is a modest amount of regionalization of MHC phenotypes in the mouse masseter. The rostral portions of the masseter are composed mostly of type IIa fibers, whereas the midsuperficial and caudal regions contain mostly type IIb fibers. Using immunoblots, we showed that castration results in an increase in the expression of type IIa MHC fibers in males. Ovariectomy has no effect on the fiber type composition in females. We conclude that testosterone plays a role in the maintenance of MHC expression in the adult male mouse masseter. 相似文献
998.
S. P. Kharitonov D. E. Nowak A. I. Nowak N. A. Egorova S. A. Korkina D. V. Osipov O. V. Natal’skaya 《Biology Bulletin》2009,36(5):469-478
Red-breasted goose colonies have been studied near Medusa Bay (73°21′N, 80°32′E), on the northwestern Taimyr Peninsula, and
along the Agapa River (70°11′N, 86°15′E) down to its mouth (71°26′N, 89° 13′E), in the central Taimyr Peninsula. Red-breasted
geese nesting near peregrine falcons are protected by the falcons from arctic foxes; however, they are sometimes attacked
by the falcons themselves. In the colonies near peregrine falcon nests, the vast majority of goose nests were situated no
farther than 100 m from the falcon nest. When food is abundant, falcons protect a larger area around their nest. The distance
between the falcon nest and the surrounding goose nests is inversely related to the falcon’s activity. In years of higher
falcon activity, falcons prevent red-breasted geese from nesting as close to their nest as in years of lower falcon activity.
Additional stimuli are required for red-breasted geese to form colonies near rough-legged buzzard nests. The distance between
snowy owl nests and red-breasted goose nests was smaller when arctic foxes were abundant than when they were scarce. 相似文献
999.
N. P. Krivosheina 《Biology Bulletin》2012,39(3):250-257
The composition of seven dipteran families from the complex of larvae dwelling in sandy soils of the southeastern Karakum Desert, represented by both free-living soil forms and endobionts ecologically dependent mainly on herbaceous plants, is analyzed. In the surface horizons of the soil, at a depth of up to 20 cm, free-living soil-dwellers form a stable complex, which includes saprophagous coleopteran larvae and their constant companions, the obligatorily predaceous dipteran larvae. Previously unknown data on the lifestyle of the larvae of five therevid genera are given. 相似文献
1000.