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Kanazuru T Sato EF Nagata K Matsui H Watanabe K Kasahara E Jikumaru M Inoue J Inoue M 《Journal of microbiology (Seoul, Korea)》2010,48(6):778-783
Some gastrointestinal bacteria synthesize hydrogen (H2) by fermentation. Despite the presence of bactericidal factors in human saliva, a large number of bacteria also live in the
oral cavity. It has never been shown that oral bacteria also produce H2 or what role H2 might play in the oral cavity. It was found that a significant amount of H2 is synthesized in the oral cavity of healthy human subjects, and that its generation is enhanced by the presence of glucose
but inhibited by either teeth brushing or sterilization with povidone iodine. These observations suggest the presence of H2-generating bacteria in the oral cavity. The screening of commensal bacteria in the oral cavity revealed that a variety of
anaerobic bacteria generate H2. Among them, Klebsiella pneumoniae (K. pneumoniae) generated significantly large amounts of H2 in the presence of glucose. Biochemical analysis revealed that various proteins in K. pneumoniae are carbonylated under standard culture conditions, and that oxidative stress induced by the presence of Fe++ and H2O2 increases the number of carbonylated proteins, particularly when their hydrogenase activity is inhibited by KCN. Inhibition
of H2 generation markedly suppresses the growth of K. pneumoniae. These observations suggest that H2 generation and/or the reduction of oxidative stress is important for the survival and growth of K. pneumoniae in the oral cavity. 相似文献
123.
Tomoyo Takeuchi Yoko Tanigawa Ryohei Minamide Kohji Ikenishi Tohru Komiya 《Mechanisms of development》2010,127(1-2):146-158
Directional migration of primordial germ cells (PGCs) toward future gonads is a common feature in many animals. In zebrafish, mouse and chicken, SDF-1/CXCR4 chemokine signaling has been shown to have an important role in PGC migration. In Xenopus, SDF-1 is expressed in several regions in embryos including dorsal mesoderm, the target region that PGCs migrate to. CXCR4 is known to be expressed in PGCs. This relationship is consistent with that of more well-known animals. Here, we present experiments that examine whether chemokine signaling is involved in PGC migration of Xenopus. We investigate: (1) Whether injection of antisense morpholino oligos (MOs) for CXCR4 mRNA into vegetal blastomere containing the germ plasm or the precursor of PGCs disturbs the migration of PGCs? (2) Whether injection of exogenous CXCR4 mRNA together with MOs can restore the knockdown phenotype? (3) Whether the migratory behavior of PGCs is disturbed by the specific expression of mutant CXCR4 mRNA or SDF-1 mRNA in PGCs? We find that the knockdown of CXCR4 or the expression of mutant CXCR4 in PGCs leads to a decrease in the PGC number of the genital ridges, and that the ectopic expression of SDF-1 in PGCs leads to a decrease in the PGC number of the genital ridges and an increase in the ectopic PGC number. These results suggest that SDF-1/CXCR4 chemokine signaling is involved in the migration and survival or in the differentiation of PGCs in Xenopus. 相似文献
124.
Introduction – Moso‐bamboo (Phyllostachys pubescens) is well known as an edible shoot in Asia, and the stems of moso‐bamboo are used as tableware due to its characteristic odour. Despite the pleasant odour of bamboo stems, no detailed analysis of the volatile compounds has been reported. Objective – To clarify the potent odourants contributing to the characteristic aroma of the bamboo, the aroma extract dilution analysis (AEDA) method was performed through gas chromatography olfactometry (GC‐O) analysis. In addition, relative flavour activity (RFA) was calculated, in which both the flavor dilution (FD) factor and weight percentage of each compound are involved. Results – Eighty‐nine compound in bamboo stems oil were identified by GC and GC‐MS. The main components of the oil were palmitic acid (16.5%), (E)‐nerolidol (10.2%) and indole (8.1%). In sensory analysis, 18 aroma‐active compounds were detected by aroma extract dilution analysis (AEDA). The most intense aroma‐active compounds were eugenol (sweet, clove‐like, green) and (E)‐2‐nonenal (green). Conclusion – The results of the sniffing test, RFA and FD factor indicated that (E)‐2‐nonenal and eugenol were estimated to have a bamboo‐like aroma, and aldehyde compounds, such as a phenylacetaldehyde (floral) and C9–C10 unsaturated aldehydes, make the aroma of bamboo. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Mori Y Shimoda K Kobayashi H Hayasaka I Hamada Y 《Primates; journal of primatology》2007,48(2):97-101
We examined the adolescent development of the sexual skin of chimpanzees (Pan troglodytes) by daily observation, evaluation of swelling, and weekly photogrametry. Although the size of swelling differed with the
individual, the development of sexual swelling followed four stages: (1) initial stage, the labial region began to show a
slight swelling and recovery; (2) labial stage, swelling at the labial region became maximal; (3) anal stage, another swelling
center appeared in the anal region and enlarged; and (4) full maturity stage, the labial and anal regions merged into a full
swelling. Menarche occurred after the beginning of the anal stage, and the regular cycle was then established. All of the
swelling stages and the peak swelling size are regarded as good indicators of reproductive maturation in chimpanzees. 相似文献
130.
Bhuiyan MS Shioda N Fukunaga K 《American journal of physiology. Endocrinology and metabolism》2007,293(6):E1606-E1614
To elucidate the molecular mechanism underlying estrogen-mediated cardioprotection in left ventricular (LV) hypertrophy and remodeling, we analyzed myocardial hypertrophy as well as cardiac function and hypertrophy-related protein expression in ovariectomized, aortic-banded rats. Wistar rats subjected to bilateral ovariectomy (OVX) were further treated with abdominal aortic stenosis. Effects on LV morphology and function were assessed using echocardiography, and expression of protein levels was determined by Western blot analysis. The heart-to-body weight ratio was most significantly increased in the OVX-pressure overload (PO) group compared with the OVX group and in the PO group compared with sham. The LV weight-to-body weight ratio was also significantly increased in the OVX-PO group compared with the OVX group and in the PO group compared with sham. The most significant increases in LV end diastolic pressure, LV developed pressure, and +/-dp/dt(max) were observed in the OVX-PO group compared with the OVX group and represent compensatory phenotypes against hypertrophy. Both endothelial nitric oxide (eNOS) synthase expression and activity was markedly reduced in the OVX-PO group, and protein kinase B (Akt) activity was largely attenuated. Marked breakdown of dystrophin was also seen in hearts of OVX-PO groups. Finally, significantly increased mortality was observed in the OVX-PO group following chronic isoproterenol administration. Our results demonstrate that rats subjected to ovariectomy are unable to compensate for hypertrophy, showed deteriorated heart function, and demonstrated increased mortality. Simultaneous impairment of eNOS and Akt activities and reduced dystrophin by ovariectomy likely contribute to cardiac decompensation during PO-induced hypertrophy in ovariectomized rats. 相似文献