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991.
Domonkos Ildiko; Malec Przemyslaw; Laczko-Dobos Hajnalka; Sozer Ozge; Klodawska Kinga; Wada Hajime; Strzalka Kazimierz; Gombos Zoltan 《Plant & cell physiology》2009,50(2):374-382
Phosphatidylglycerol (PG) depletion suppressed the oxygen-evolvingactivity of Synechocystis PCC6803 pgsA mutant cells. Shortageof PG led to decreased photosynthetic activity, which, similarto the effect of high light exposure, is likely to generatethe production of reactive oxygen species (ROS) or free radicals.Protection of the PG-depleted cells against light-induced damageincreased the echinenone and myxoxanthophyll content of thecells. The increased carotenoid content was localized in a solublefraction of the cells as well as in isolated thylakoid and cytoplasmicmembranes. The soluble carotenoid fraction contained carotenederivatives, which may bind to proteins. These carotene–proteincomplexes are similar to orange carotenoid protein that is involvedin yielding protection against free radicals and ROS. An increasein the content of myxoxanthophyll and echinenone upon PG depletionsuggests that PG depletion regulates the biosynthetic pathwayof specific carotenoids. 相似文献
992.
Methylguanidine (MG) is known as not only a nephrotoxin but also as a neurotoxine. We have previously showed that MG itself
generates hydroxyl radicals (•OH) in an in vitro study. In this study, we examined the inhibitory effects of ascorbate, EPC-K1 (α-tocopheryl-l-ascorbate-2-O-phosphate diester), Trolox (water-soluble vitamin E analogue), and glutathione (GSH) on •OH generation from
MG using an electron spin resonance (ESR) spectrometry with spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). It was found
that these compounds have potent inhibitory effect on •OH generation from MG in the order of ascorbate > GSH > EPC-K1 > Trolox.
Special issue article in honor of Dr. Akitane Mori. 相似文献
993.
Glucose metabolism is essential for normal brain function and plays a vital role in synaptic transmission. Recent evidence
suggests that ATP synthesized locally by glycolysis, particularly via glyceraldehyde 3-phosphate dehydrogenase/3-phosphoglycerate
kinase, is critical for synaptic transmission. We present evidence that ATP generated by synaptic vesicle-associated pyruvate
kinase is harnessed to transport glutamate into synaptic vesicles. Isolated synaptic vesicles incorporated [3H]glutamate in the presence of phosphoenolpyruvate (PEP) and ADP. Pyruvate kinase activators and inhibitors stimulated and
reduced PEP/ADP-dependent glutamate uptake, respectively. Membrane potential was also formed in the presence of pyruvate kinase
activators. “ATP-trapping” experiments using hexokinase and glucose suggest that ATP produced by vesicle-associated pyruvate
kinase is more readily used than exogenously added ATP. Other neurotransmitters such as GABA, dopamine, and serotonin were
also taken up into crude synaptic vesicles in a PEP/ADP-dependent manner. The possibility that ATP locally generated by glycolysis
supports vesicular accumulation of neurotransmitters is discussed.
Atsuhiko Ishida—On leave from the Department of Biochemistry, Asahikawa Medical College, Asahikawa, Japan. 相似文献
994.
Kaoru Wada Sachiko Mizoguchi Yoshinori Ito Jun-ichi Kawada Yohei Yamauchi Tsuneo Morishima Yukihiro Nishiyama Hiroshi Kimura 《Microbiology and immunology》2009,53(1):22-29
A simultaneous detection system to quantify HSV, HHV-6, and HHV-7 DNA via multiplex real-time PCR using different fluorochromes was developed. The minimum quantitative level established via this multiplex assay was four copies per reaction for HSV type 1, four copies for HHV-6, and three copies for HHV-7, respectively. The dynamic range encompassed at least six orders of magnitude. The system was specific and reproducible even in the presence of large amounts of other viral DNA. We then applied this multiplex real-time PCR assay to 105 CSF specimens obtained from subjects less than 15 years old in whom a diagnosis of viral encephalitis/encephalopathy was suspected on clinical grounds. The detection rate for each viral DNA was 6.7% for HSV, 9.5% for HHV-6, and 1.9% for HHV-7. These results indicate that our system is reliable and may be useful for the rapid diagnosis of viral encephalitis/encephalopathy. 相似文献
995.
The effects of light on the spore germination of a hornwort species,Anthoceros miyabeanus Steph., were investigated. Spores of this species were photoblastic, but their sensitivities to light quality were different.
Under either continuous white, red or diffused daylight, more than 80% of the spores germinated, but under blue light none
or a few of them germinated. Under continuous far-red light or in total darkness, the spores did not germinate at all.Anthoceros spores required red light irradiation for a very long duration, i.e., over 12–24 hr of red light for saturated germination.
However, the spore germination showed clear photo-reversibility by repeated irradiation of red and far-red light.
The germination pattern clearly varied with the light quality. There were two fundamental patterns; (1) cell mass type in
white or blue light: spores divide before germination, and the sporelings divide frequently and form 1–2 rhizoids soon after
germination, and (2) germ tube type in red light: spores germinate without cell division, and the single-cell sporelings elongate
without cell division and rhizoid formation. 相似文献
996.
997.
Tomomi Kimiwada Mikako Sakurai Hiroki Ohashi Shunsuke Aoki Teiji Tominaga Keiji Wada 《Neurochemistry international》2009,54(5-6):277-285
The circadian clock system plays multiple roles in our bodies, and clock genes are expressed in various brain regions, including the lateral subventricular zone (SVZ) where neural stem/progenitor cells (NSPCs) persist and postnatal neurogenesis continues. However, the functions of clock genes in adult NSPCs are not well understood. Here, we first investigated the expression patterns of Clock and Bmal1 in the SVZ by immunohistochemistry and then verified how the expression levels of 17 clock and clock-related genes changed during differentiation of cultured adult NSPCs using quantitative RT-PCR. Finally, we used RNAi to observe the effects of Clock and Bmal1 on neuronal differentiation. Our results revealed that Clock and Bmal1 were expressed in the SVZ and double-stained with the neural progenitor marker Nestin and neural stem marker GFAP. In cultured adult NSPCs, the clock genes changed their expression patterns during differentiation, and interestingly, Bmal1 started endogenous oscillation. Moreover, gene silencing of Clock or Bmal1 by RNAi decreased the percentages of neuronal marker Map2-positive cells and expression levels of NeuroD1 mRNA. These findings suggest that clock genes are involved in the neuronal differentiation of adult NSPCs and may extend our understanding of various neurological/psychological disorders linked to adult neurogenesis and circadian rhythm. 相似文献
998.
999.
Chloroplast photorelocation movement in green plants is generally mediated by blue light. However, in cryptogam plants, including
ferns, mosses, and algae, both red light and blue light are effective. Although the photoreceptors required for this phenomenon
have been identified, the mechanisms underlying this movement response are not yet known. In order to analyze this response
in more detail, chloroplast movement was induced in dark-adapted Adiantum
capillus-veneris gametophyte cells by partial cell irradiation with a microbeam of red and/or blue light. In each case, chloroplasts were
found to move toward the microbeam-irradiated area. A second microbeam was also applied to the cell at a separate location
before the chloroplasts had reached the destination of the first microbeam. Under these conditions, chloroplasts were found
to change their direction of movement without turning and move toward the second microbeam-irradiated area after a lag time
of a few minutes. These findings indicate that chloroplasts can move in any direction and do not exhibit a polarity for chloroplast
accumulation movement. This phenomenon was analyzed in detail in Adiantum and subsequently confirmed in Arabidopsis
thaliana palisade cells. Interestingly, the lag time for direction change toward the second microbeam in Adiantum was longer in the red light than in the blue light. However, the reason for this discrepancy is not yet understood.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
1000.
Identifying ecological factors associated with local differentiation of populations is important for understanding microevolutionary processes. Alpine environments offer a unique opportunity to investigate the effects of habitat-specific selective forces and gene flow limitations among populations at a microscale on local adaptation because the heterogeneous snowmelt patterns in alpine ecosystems provide steep environmental changes. We investigated the variation in morphological traits and enzyme loci between fellfield and snowbed populations of Potentilla matsumurae, a common alpine herb with a wide distribution along snowmelt gradients in northern Japan. We found significant differences in morphological traits between fellfield and snowbed habitats in a northern distribution region. These differences were maintained when plants were grown under uniform conditions in a greenhouse. Allozyme variations among 15 populations from geographically separated regions with different historical backgrounds showed that the populations are more genetically differentiated between the fellfield and snowbed habitats within a region than between populations occupying the same habitat type in different regions. These results suggest that variation in snowmelt regimes could be a driving force creating local adaptation and genetic differentiation of alpine plant populations. 相似文献