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91.
92.
Toshio Sugimoto Tsutomu Kawasaki Tomohiko Kato Robert F. Whittier Daisuke Shibata Yukio Kawamura 《Plant molecular biology》1992,20(4):743-747
A full-length cDNA encoding a subunit of phosphoenolpyruvate carboxylase (PEPC) was isolated from a developing seed expression library of the C3 plant Glycine max. The corresponding mRNA is present at similar levels in leaf, stem, root and developing seed. Two potential start codons exist, and the activity of protein initiated from the first such codon could be subject to regulation by protein kinase. Sequence comparison shows a similar upstream start codon in the case of the Ppc2 gene from Mesembryanthemum crystallinum, previously assumed to lack the sequences necessary for phosphorylation. The soybean encoded protein tends to resemble other C3-type PEPC proteins more closely than those implicated in C4 or crassulacean acid metabolism. 相似文献
93.
Application of the voltage clamp technique to cardiac primary pacemaker tissue has yielded sufficiently detailed information that a qualitative model of the pacemaker response can now be formulated. One important difference between the generation of spontaneous activity in sinus tissue, and in the Purkinje fiber, appears to be the involvement of the slow inward current, Isi, in the sinus pacemaker depolarization. The voltage clamp results also demonstrate the importance of the Isi in the chronotropic responses of pacemaker tissue. Epinephrine has been shown to increase Isi in rabbit sinoatrial node, and there is indirect evidence that acetylcholine may reduce Isi in reptilian sinus venosus. Additional, more quantitative data are essential, however, before cardiac primary pacemaker activity and its modulation by the autonomic transmitters can be fully understood. 相似文献
94.
Murakami K Irie K Morimoto A Ohigashi H Shindo M Nagao M Shimizu T Shirasawa T 《The Journal of biological chemistry》2003,278(46):46179-46187
Cerebral amyloid angiopathy (CAA) due to beta-amyloid (Abeta) is one of the specific pathological features of familial Alzheimer's disease. Abeta mainly consisting of 40- and 42-mer peptides (Abeta40 and Abeta42) exhibits neurotoxicity and aggregative abilities. All of the variants of Abeta40 and Abeta42 found in CAA were synthesized in a highly pure form and examined for neurotoxicity in PC12 cells and aggregative ability. All of the Abeta40 mutants at positions 22 and 23 showed stronger neurotoxicity than wild-type Abeta40. Similar tendency was observed for Abeta42 mutants at positions 22 and 23 whose neurotoxicity was 50-200 times stronger than that of the corresponding Abeta40 mutants, suggesting that these Abeta42 mutants are mainly involved in the pathogenesis of CAA. Although the aggregation of E22G-Abeta42 and D23N-Abeta42 was similar to that of wild-type Abeta42, E22Q-Abeta42 and E22K-Abeta42 aggregated extensively, supporting the clinical evidence that Dutch and Italian patients are diagnosed as hereditary cerebral hemorrhage with amyloidosis. In contrast, A21G mutation needs alternative explanation with the exception of physicochemical properties of Abeta mutants. Attenuated total reflection-Fourier transform infrared spectroscopy spectra suggested that beta-sheet content of the Abeta mutants correlates with their aggregation. However, beta-turn is also a critical secondary structure because residues at positions 22 and 23 that preferably form two-residue beta-turn significantly enhanced the aggregative ability. 相似文献
95.
Leaf physiological and gas-exchange traits of a summer-green herbaceous perennial, Parasenecio yatabei, growing along a stream were examined in relation to leaf age. In its vegetative phase, the aerial part of this plant consists
of only one leaf and provides an ideal system for the study of leaf longevity. Volumetric soil water content (SWC) decreased
with increasing distance from the stream, whereas relative light intensity was nearly constant. The light-saturated net CO2 assimilation rate (A
sat) and leaf stomatal conductance (gs) were approximately 1.5-fold and 1.4-fold higher, respectively, in the lower slope near
the mountain stream than in the upper slope far from the mountain stream. The lifespan of aerial parts of vegetative plants
significantly increased with decreasing SWC. The leaf mass-based nitrogen content of the leaves (N
mass) was almost constant (ca. 2.2%); however, the maximum carboxylation rate by ribulose-1,5-biphosphate carboxylase/oxygenase
(rubisco) (V
cmax) and photosynthetic nitrogen use efficiency (PNUE, A
sat/N
area) decreased more slowly in the upper slope than in the lower slope. The higher leaf photosynthetic activity of P. yatabei plants growing lower on the slope leads to a decrease in V
cmax and PNUE in the early growing season, and to a shorter leaf lifespan. 相似文献
96.
WAVE2 deficiency reveals distinct roles in embryogenesis and Rac-mediated actin-based motility 总被引:11,自引:0,他引:11
Yan C Martinez-Quiles N Eden S Shibata T Takeshima F Shinkura R Fujiwara Y Bronson R Snapper SB Kirschner MW Geha R Rosen FS Alt FW 《The EMBO journal》2003,22(14):3602-3612
The Wiskott-Aldrich syndrome related protein WAVE2 is implicated in the regulation of actin-cytoskeletal reorganization downstream of the small Rho GTPase, Rac. We inactivated the WAVE2 gene by gene-targeted mutation to examine its role in murine development and in actin assembly. WAVE2-deficient embryos survived until approximately embryonic day 12.5 and displayed growth retardation and certain morphological defects, including malformations of the ventricles in the developing brain. WAVE2-deficient embryonic stem cells displayed normal proliferation, whereas WAVE2-deficient embryonic fibroblasts exhibited severe growth defects, as well as defective cell motility in response to PDGF, lamellipodium formation and Rac-mediated actin polymerization. These results imply a non-redundant role for WAVE2 in murine embryogenesis and a critical role for WAVE2 in actin-based processes downstream of Rac that are essential for cell movement. 相似文献
97.
Proteome analysis of programmed cell death and defense signaling using the rice lesion mimic mutant cdr2 总被引:7,自引:0,他引:7
Tsunezuka H Fujiwara M Kawasaki T Shimamoto K 《Molecular plant-microbe interactions : MPMI》2005,18(1):52-59
We have previously identified three lesion-mimic mutants, cell death and resistance (cdr), in rice. These mutants induce a series of defense responses, including expression of defense-related genes and high accumulation of phytoalexins, indicating that the cdr mutants are useful materials to study programmed cell death and defense signaling in rice. Here, we carried out a proteome analysis of the cdr2 mutant. Total proteins prepared from the wild type and the cdr2 mutant at three different stages of lesion formation were compared using two-dimensional electrophoresis. We found a total of 37 proteins that were differentially expressed between cdr2 and wild type. Among them, 28 spots were up-regulated and nine were down-regulated in the cdr2 mutant. All the protein spots were identified by mass spectrometric analysis. These differentially regulated proteins included defense-related proteins. In addition, 27 proteins were classified as metabolic enzymes, suggesting that the programmed cell death that occurs in the cdr2 mutant is associated with active metabolic changes. Our study shows that proteome analysis is a useful approach to study programmed cell death and defense signaling in plants. 相似文献
98.
Kerstin Törner Takashi Nakanishi Tomoaki Matsuura Yasuhiko Kato Hajime Watanabe 《Molecular genetics and genomics : MGG》2014,289(4):707-715
The water flea Daphnia is a new model organism for ecological, evolutionary, and toxicological genomics. Detailed functional analysis of genes newly discovered through genomic approaches often requires overexpression of the identified protein. In the present study, we report the microinjection of in vitro-synthesized RNAs into the eggs as a method for overexpressing ubiquitous proteins in Daphnia magna. We injected a 1.3-kb mRNA that coded for the red fluorescent protein (DsRed2) flanked by UTRs from the ubiquitously expressed elongation factor 1α-1 (EF1α-1) into D. magna embryos. DsRed2 fluorescence in the embryos was measured 24 h after microinjection. Unexpectedly, the reporter RNA containing the 522-bp full-length EF1α-1 3′ UTR failed to induce fluorescence. To assess reporter expression, the length of the 3′ UTR that potentially contained negative regulatory elements of protein expression, including AU-rich regions and Musashi binding elements, was serially reduced from the 3′ end. Assessing all injected RNA alternatives, mRNA containing the first 60 bp of the 3′ UTR gave rise to the highest fluorescence, 14 times the Daphnia auto-fluorescence. In contrast, mRNA lacking the entire 3′ UTR hardly induced any change in fluorescence intensity. This is the first evaluation of UTRs of mRNAs delivered into Daphnia embryos by microinjection for overexpressing proteins. The mRNA with truncated 3′ UTRs of Daphnia EF1α-1 will be useful not only for gain-of-function analyses but also for labeling proteins and organelles with fluorescent proteins in Daphnia. 相似文献
99.
Hajime Otani Hitomi Otan Masao Morita Dipak K. Das 《Molecular and cellular biochemistry》1989,90(2):111-120
We investigated the effect of Ca2+ overload on the phospholipase C-catalyzed hydrolysis of phosphoinositides in the rat left ventricular papillary muscle. Ca2+ overload on the papillary muscle was induced by treatment with 0.3 mM ouabain in Ca2+-containing medium following either Ca2+-containing or Ca2+-free superfusion. The phosphoinositide breakdown was evaluated by determining accumulations of [3H]inositol phosphates ([3H]IPs) in the tissues prelabeled with [3H]inositol. Ca2+ repletion following Ca2+-free superfusion resulted in a rapid but small increase in resting tension that was not followed by contracture, nor was it associated with a significant increase in [3H]IPs accumulations. Treatment with ouabain following Ca2+-containing superfusion increased resting tension after a lag period of several minutes and produced contracture associated with an increase in [3H]IPs accumulations. The ouabain induced increases in resting tension, and accumulations of [3H]IPs were significantly potentiated by prior Ca2+-free superfusion instead of Ca2+-containing superfusion. There was a significant positive correlation between increases in resting tension and the phosphoinositide breakdown. The increased resting tension and the accumulations of [3H]IPs were not antagonized by treatments with prazosin plus atropine or indomethacin, but were abolished by superfusion with Ca2+-free buffer solution. Although the enhanced phospholipase C-catalyzed hydrolysis of phosphoinositides appears to be a consequence rather than a cause of increased intracellular Ca2+, such a biochemical change may provoke a positive feedback mechanism to develop the muscle contracture through the putative intracellular messenger action of inositol triphosphate and diacylglycerol.Abbreviations [3H]IPs
[3H]Inositol Phosphates
- IP
Inositol Phosphate
- IP2
Inositol Bisphosphate
- IP3
Inositol Trisphosphate
- PI
Phosphatidylinositol
- PI-4-P
Phosphatidylinositol-4-phosphate
- PI-4,5-P2
Phosphatidylinositol 4,5-bisphosphate
- PRZ
Prazosin
- ATR
Atropine
- INDO
Indomethacin
- min
Minutes 相似文献
100.
Tomonori Deguchi Kazuhiro E. Fujimori Takashi Kawasaki Hajime Ohgushi Shunsuke Yuba 《Gene expression patterns : GEP》2009,9(5):341-347
Prox1 is a prospero-related homeobox gene. Prox1 is expressed in various internal organs and is related to those differentiations. Small fishes such as the zebrafish and the medaka are useful model animals in the clarification of the mechanism of development. The zebrafish prox1 is also identified, and it contributes to clarifying the function of prox1. However, it is necessary to note that many genes are duplicated in teleost fishes. In this study, we identified the orthologs of the mammalian prox1 gene in the medaka. The gene was also duplicated in the medaka, and we named it prox1a and prox1b. In silico analysis from the perspective of synteny indicated that medaka prox1a was similar to the prox1 gene of other vertebrates. Medaka prox1a was expressed in all internal organs that we have examined by RT-PCR. In contrast, medaka prox1b expression was limited to the brain, heart, liver, kidney, thymus, gill, testis, and ovary. This suggests that the two prox1 genes do not have a complementary relationship. In addition, we examined their expression patterns during embryonic development using whole-mount in situ hybridization. The expression pattern of prox1a showed a pattern similar to that of zebrafish prox1. In contrast, medaka prox1b was expressed asymmetrically in part of the central nervous system, especially strongly in the right side of the habenula. 相似文献