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231.
Two fertility inhibition (Fi+) functions which reduce R388(Inc W) transfer were detected on RP1(Inc P). Neither function affected R388-mediated surface exclusion but they could be distinguished by their effect on pilus production. One of the functions was located in the 6.5-kb Pst1-C region of RP1, part or all of which also occurs on six Fi+ but not two Fi? Inc P plasmids studied. 相似文献
232.
Melanoides tuberculata in the Kuala Lumpur area of Malaysia were found to be entirely female, reproducing parthenogenetically. The reproductive system is extremely simple in structure and histology, lacking all the glandular developments common in most mesogastropods. Eggs pass into a cephalic brood-pouch where they develop to juveniles of 5–6 shell whorls before emergence. Numbers of developing young in the brood-pouches increased with shell height of the parents except for a decline in the few very largest snails. The highest brood-pouch count was 265, but average counts were much lower. 85 % of developing young in the brood-pouches were very early stages from eggs to embryos of one whorl only, perhaps implying that many eggs fail to develop successfully to young snails. Three localities studied yielded consistently different brood-pouch counts, implying variation in fecundity. Juveniles emerge from the brood-pouch most commonly between nightfall and midnight and normal emergence seems to require diurnal alternation of light and dark. In continuous darkness, brood-pouch counts increased markedly, perhaps as a result of greater activity and feeding during darkness. Several features of the reproductive biology suggest that Melanoides might become a useful experimental animal in freshwater studies. 相似文献
233.
Ul Haq Zaheer Uddin Reaz Wai Lam Kok Wadood Abdul Lajis Nordin Haji 《Journal of molecular modeling》2011,17(5):1149-1161
Structure-based 3D-QSAR approaches (CoMFA and CoMSIA) were applied to understand the structural requirements of the Cyclin-dependent
kinase 5/p25 inhibitors. Cyclin-dependent kinase 5 (CDK5) is believed to play an important role in the development of the
central nervous system during the process of mammalian embryogenesis. Genetic algorithm based docking program (GOLD) was successfully
utilized to orient the compounds inside the binding pocket of the CDK5/p25 structure. The adapted alignment method with the
suitable parameters resulted in a reliable model. Furthermore, the final model was robust enough to forecast the activities
of test compounds, satisfactorily. The contour maps were produced around the functional groups to understand the SAR requirements.
Moreover, we also investigate the structural attributes of the inhibitors which make them selective toward CDK5/p25 over its
close counterpart, i.e., CDK2. The study could be helpful to rationalize the new compounds with better inhibition and selectivity
profiles against CDK5/p25. 相似文献
234.