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91.
Kimura Y Alric J Verméglio A Masuda S Hagiwara Y Matsuura K Shimada K Nagashima KV 《The Journal of biological chemistry》2007,282(9):6463-6472
A new type of membrane-bound cytochrome c was found in a marine purple photosynthetic bacterium, Rhodovulum sulfidophilum. This cytochrome c was significantly accumulated in cells growing under anaerobic photosynthetic conditions and showed an apparent molecular mass of approximately 100 kDa when purified and analyzed by SDS-PAGE. The midpoint potential of this cytochrome c was 369 mV. Flash-induced kinetic measurements showed that this new cytochrome c can work as an electron donor to the photosynthetic reaction center. The gene coding for this cytochrome c was cloned and analyzed. The deduced molecular mass was nearly equal to 50 kDa. Its C-terminal heme-containing region showed the highest sequence identity to the water-soluble cytochrome c(2), although its predicted secondary structure resembles that of cytochrome c(y). Phylogenetic analyses suggested that this new cytochrome c has evolved from cytochrome c(2). We, thus, propose its designation as cytochrome c(2m). Mutants lacking this cytochrome or cytochrome c(2) showed the same growth rate as the wild type. However, a double mutant lacking both cytochrome c(2) and c(2m) showed no growth under photosynthetic conditions. It was concluded that either the membrane-bound cytochrome c(2m) or the water-soluble cytochrome c(2) work as a physiological electron carrier in the photosynthetic electron transfer pathway of Rvu. sulfidophilum. 相似文献
92.
Our previous studies on scalp-recorded event-related potentials (ERPs) showed that somatosensory N140 evoked by a tactile vibration in working memory tasks was enhanced when human subjects expected a coming visual stimulus that had been paired with the tactile stimulus. The results suggested that such enhancement represented the cortical activities involved in tactile-visual crossmodal association. In the present study, we further hypothesized that the enhancement represented the neural activities in somatosensory and frontal cortices in the crossmodal association. By applying independent component analysis (ICA) to the ERP data, we found independent components (ICs) located in the medial prefrontal cortex (around the anterior cingulate cortex, ACC) and the primary somatosensory cortex (SI). The activity represented by the IC in SI cortex showed enhancement in expectation of the visual stimulus. Such differential activity thus suggested the participation of SI cortex in the task-related crossmodal association. Further, the coherence analysis and the Granger causality spectral analysis of the ICs showed that SI cortex appeared to cooperate with ACC in attention and perception of the tactile stimulus in crossmodal association. The results of our study support with new evidence an important idea in cortical neurophysiology: higher cognitive operations develop from the modality-specific sensory cortices (in the present study, SI cortex) that are involved in sensation and perception of various stimuli. 相似文献
93.
Komazaki S Takano K 《Journal of experimental zoology. Part A, Ecological genetics and physiology》2007,307(3):156-162
The influence of an alternating electromagnetic field (EMF) on early development of amphibian embryos was examined. When the embryos developed under the influence of a low-frequency EMF (50 Hz, 5-30 mT), the rate of early development was accelerated. The effect of EMF was exerted preferentially at the gastrula stage, and the period of gastrulation was shortened. Histological observations showed that EMF promoted morphogenetic cell movements during the gastrulation. The concentration of intracellular free Ca2+ ([Ca2+]i) in the embryonic cells under the influence of EMF was analyzed using Fura-2, an indicator of the intracellular concentration of calcium ions. The influence of EMF on [Ca2+]i was analyzed in embryonic cells isolated from blastula, gastrula, and neurula, EMF increased a [Ca2+]i particularly in the cells isolated from gastrula. Our results suggest that EMF specifically increased the [Ca2+]i of gastrula cells, thereby, accelerating the rate of morphogenetic cell movements during gastrulation. 相似文献
94.
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96.
Makoto Bannai Katsushi Tokunaga Tadashi Imanishi Shinji Harihara Kiyoshi Fujisawa Takeo Juji Keiichi Omoto 《American journal of physical anthropology》1996,101(1):1-9
The Ainu people are considered to be the descendants of preagricultural native populations of northern Japan, while the majority of the population of contemporary Japan (Wajin) is descended mainly from postneolithic migrants. Polymorphisms of the HLA-DRB1, DRB3, and DQB1 alleles were investigated in DNA samples of 50 Ainu living in Hidaka district, Hokkaido. Unique features of the Ainu in this study were high incidences of DRB1*1401, DRB1*1406, and a newly described allele, DRB1*1106 (20%, 17%, and 5%, respectively). On the other hand, several common alleles in Wajin (DRB1*1502, 1302, 0803, and 1501) were found at relatively low frequencies (1–2%) in Ainu. Previously DRB1*1406 was described as a characteristic allele of some Native American or northeast Asian ethnic groups, and DRB1*1106 had been found in only two Singapore Chinese and one Korean. Principal component analysis of various populations based on HLA class II allele frequencies places the Ainu population midway between other east Asian populations, including Wajin, and Native Americans. These observations may support the hypothesis that the Ainu people are the descendants of some Upper Paleolithic populations of northeast Asia from which Native Americans are also descended. © 1996 Wiley-Liss, Inc. 相似文献
97.
98.
M Yoshiyama H Sakai M Teragaki K Takeuchi T Takeda M Ikata M Ishikawa I Miura 《Biochemical and biophysical research communications》1988,151(3):1408-1415
Perfused guinea-pig hearts, which were analyzed by 31P-MRS, were subjected to 30 and 60 minute ischemia and reperfused using two perfusates, one containing 200 microM inosine, and the other without inosine. After 4 hour reperfusion with inosine, ATP levels increased to 95.5% of preischemic value (30 minute ischemia) and 76.2% (60 minute ischemia). However, after 4 hour reperfusion without inosine, ATP levels increased only to 72.2% (30 minute ischemia) and to 48.2% (60 minute ischemia). In 60 minute ischemic hearts reperfused with inosine, left ventricular maximal positive dp/dt (LV dp/dt) was improved significantly to 82.4% after 6 hour reperfusion in contrast to hearts reperfused without inosine (43.1%). Administration of inosine was very useful for increasing myocardial gross energy product and improving cardiac performance. 相似文献
99.
Jin‐Shu Yang Hiromichi Nagasawa Yoshihiro Fujiwara Shinji Tsuchida Wei‐Jun Yang 《Zoologica scripta》2010,39(6):621-630
Yang, J.‐S., Nagasawa, H., Fujiwara, Y., Tsuchida, S. & Yang, W.‐J. The complete mitogenome of the hydrothermal vent crab Gandalfus yunohana (Crustacea: Decapoda: Brachyura): a link between the Bythograeoidea and Xanthoidea. —Zoologica Scripta, 39, 621–630. Metazoan mitochondrial genomes (mitogenomes) are often used for all‐level phylogenetic analyses and evolution modelling. Although mitochondrial fragments facilitate studying the occurrence and dispersal of hydrothermal‐vent species, few complete mitogenomes have been determined for comprehensive analyses. We determined the complete nucleotide sequence of the bythograeid crab Gandalfus yunohana. The G. yunohana mitogenome is 15 567 bp in length and with an AT content of 69.9%. A putative control region of 625 bp was identified due to its position (between rrnS and trnI) and AT richness (72.8%), which exhibits high similarity with that of the Australian giant crab Pseudocarcinus gigas. The mitochondrial gene order is identical to the typical brachyuran mode. Codon usage, nucleotide composition and bias are well conserved as the Brachyura. Phylogenetic analyses from protein‐coding genes indicated its closest relationship with P. gigas. All the results support the close evolution distance between the Bythograeoidea and Xanthoidea, which might imply the possible origin that the only superfamily of vent crabs underwent. The G. yunohana mitogenome exhibits highly conserved characteristics with those of other decapods, especially its close relative brachyurans. A recent origin rather than the relic fauna was suggested. The present study will supply considerable data of use for both genomics and evolutionary research on hydrothermal vent ecosystems. 相似文献
100.
Using a pair of plasmids carrying the rpsL target sequence in different orientations to the replication origin, we analyzed a large number of forward mutations generated in wild-type and mismatch-repair deficient (MMR(-)) Escherichia coli cells to assess the effects of directionality of replication-fork movement on spontaneous mutagenesis and the generation of replication error. All classes of the mutations found in wild-type cells but not MMR(-) cells were strongly affected by the directionality of replication fork movement. It also appeared that the directionality of replication-fork movement governs the directionality of sequence substitution mutagenesis, which occurred in wild-type cells at a frequency comparable to base substitutions and single-base frameshift mutations. A very strong orientation-dependent hot-spot site for single-base frameshift mutations was discovered and demonstrated to be caused by the same process involved in sequence substitution mutagenesis. It is surprising that dnaE173, a potent mutator mutation specific for sequence substitution as well as single-base frameshift, did not enhance the frequency of the hot-spot frameshift mutation. Furthermore, the frequency of the hot-spot frameshift mutation was unchanged in the MMR(-) strain, whereas the mutHLS-dependent mismatch repair system efficiently suppressed the generation of single-base frameshift mutations. These results suggested that the hot-spot frameshift mutagenesis might be initiated at a particular location containing a DNA lesion, and thereby produce a premutagenic replication intermediate resistant to MMR. Significant numbers of spontaneous single-base frameshift mutations are probably caused by similar mechanisms. 相似文献