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M Kwiatkowska K Pop?ońska A Gosek 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》1999,37(3):219-221
Autoradiographic research with the use of 3H-leucine demonstrates that circadian rhythm of protein synthesis characteristic of manubria at the proliferative phase of spermatogenesis in Chara vulgaris disappears after symplasmic isolation of antheridium from thallus during the time preceding block of DNA endoreplication in manubria following initiation of spermiogenesis insensitive to light. 相似文献
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Kerry-Ann da Costa Kiranmai S. Rai Corneliu N. Craciunescu Komal Parikh Mihai G. Mehedint Lisa M. Sanders Audrey McLean-Pottinger Steven H. Zeisel 《The Journal of biological chemistry》2010,285(2):1008-1015
The development of fetal brain is influenced by nutrients such as docosahexaenoic acid (DHA, 22:6) and choline. Phosphatidylethanolamine-N-methyltransferase (PEMT) catalyzes the biosynthesis of phosphatidylcholine from phosphatidylethanolamine enriched in DHA and many humans have functional genetic polymorphisms in the PEMT gene. Previously, it was reported that Pemt−/− mice have altered hippocampal development. The present study explores whether abnormal phosphatidylcholine biosynthesis causes altered incorporation of DHA into membranes, thereby influencing brain development, and determines whether supplemental dietary DHA can reverse some of these changes. Pregnant C57BL/6 wild type (WT) and Pemt−/− mice were fed a control diet, or a diet supplemented with 3 g/kg of DHA, from gestational day 11 to 17. Brains from embryonic day 17 fetuses derived from Pemt−/− dams fed the control diet had 25–50% less phospholipid-DHA as compared with WT (p < 0.05). Also, they had 60% more neural progenitor cell proliferation (p < 0.05), 60% more neuronal apoptosis (p < 0.01), and 30% less calretinin expression (p < 0.05; a marker of neuronal differentiation) in the hippocampus compared with WT. The DHA-supplemented diet increased fetal brain Pemt−/− phospholipid-DHA to WT levels, and abrogated the neural progenitor cell proliferation and apoptosis differences. Although this diet did not change proliferation in the WT group, it halved the rate of apoptosis (p < 0.05). In both genotypes, the DHA-supplemented diet increased calretinin expression 2-fold (p < 0.05). These results suggest that the changes in hippocampal development in the Pemt−/− mouse could be mediated by altered DHA incorporation into membrane phospholipids, and that maternal dietary DHA can influence fetal brain development. 相似文献
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G Benga O Popescu V Borza A Hodarn?u V I Pop J Wrigglesworth 《Biochimica et biophysica acta》1991,1061(2):309-312
The water diffusional permeability of human red blood cells following exposure to various sulfhydryl group (SH) reagents have been studied using a nuclear magnetic resonance technique. Exposure of red blood cells up to 12 mM N-ethylmaleimide (NEM) or 10 mM 5,5'-dithio-bis(2-nitrobenzoic acid) (DTNE) alone does not affect water diffusion. In contrast, when DTNB treatment follows a preincubation of the cells with NEM, a small (18% at 37 degrees C) but significant inhibition of water permeability occurs. The NEM and DTNB treatment of the cells caused no change of the cell shape and volume or of the cell water volume. Consequently, the inhibition observed after NEM and DTNB treatment has a real significance. 相似文献
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A Pop A Opri?an A Pop A Cerbu M Stavarache R Ni?u 《Archives roumaines de pathologie expérimentales et de microbiologie》1989,48(4):373-378
The frequency of Toxoplasma gondii infection in the meat provided by two abattoirs, as well as the pathogenicity of the isolated strains were studied. The parasite carriage was investigated on 299 pools of diaphragmatic muscle (1 pool = 10 animals) from 740 swine, 910 cattle and 1340 sheep: the methods used were bioassays on mice and the precocious identification of the tachyzoites in the peritoneal exudate and after 30 days the cerebral cysts. There were obtained 27 positive results (9.01%), in the examined pools of meat, without significant differences as concerns the frequency in relation to the animal species. Out of these strains two were virulent for mice and rabbits. 相似文献