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1.
Estrogen can regulate the cell cycle in the early G1 phase of yeast by increasing the amount of adenylate cyclase mRNA 总被引:4,自引:0,他引:4
The effects of beta-estradiol (estrogen; a minor component of yeast cells) on S. cerevisiae cells in the G0 and G1 phases were examined. Results showed that estrogen stimulated the recovery of growth from G0 arrest induced by nutrient limitation or ts mutation of cdc35 (adenylate cyclase) in the early G1 phase, and inhibited entry into the resting G0 phase by increasing the intracellular cAMP level. However, estrogen had no effect on late G1 arrest induced by the alpha factor or ts mutation of cdc36. Estrogen was found to lead to higher steady-state levels of adenylate cyclase mRNA but not to affect the expression of the RAS1 and RAS2 genes, although these can also alter the intracellular cAMP level. These results suggest that estrogen influences the cell cycle of yeast in the early G1 phase by controlling the level of cAMP through the increase of adenylate cyclase mRNA. 相似文献
2.
It is often reported that an animal with spotty coat markings on its body has a tail with stripe-shaped pattern. In other various biological and chemical phenomena in/on cylinder-like domains, longitudinally periodic band patterns are observed much more often than the other non-uniform patterns. This paper mathematically explains these observations by proving that, in/on a long and narrow cylinder-like domain, any solution of reaction-diffusion system asymptotically loses its spatial dependence in the transectional/circumferential direction. 相似文献
3.
Synaptosomal membrane proteins solubilized with 8% CHAPS-8 M urea were analyzed with twodimensional electrophoresis (2DE). The membrane proteins were resolved up to 250 spots on a 2DE map, ranging in isoelectric points (pI) from 3.5 to 10.0 and molecular weights (MW) from 10 kDa to 200 kDa. Comparison of the mapped proteins of synaptosomal membranes with those of myelin and mitochondorial membranes revealed that synaptosomal membrane proteins were characteristic in the area of pI from 4.0 to 7.5 and MW from 20 kDa to 130 kDa, and that at least 30 spots were synaptosomal membrane-specific proteins. Most of these 30 proteins have not been previously described, named, and characterized Serial numbers (from SY1 to SY30) were assigned to the proteins on the map in order to investigate them systematically. A preliminary attempt to separate synaptosomal membrane proteins was carried out using a reversed-phase HPLC system. Several proteins could either be isolated or enriched. SY10 (pI 4.6; MW 56 kDa) was one of these proteins, and was of particular interest for its unusual behavior on the reversed-phase column, and for its binding to an immobilized protein A-gel. 相似文献
4.
Noriaki Murakami Yoshiyuki Tanaka Kunio Takishima Yuzo Minobe Makoto Matsuoka Sei-Ichiro Kiyota Shin-ichi Hatanaka Katsuhiro Sakano 《Journal of plant research》1990,103(4):419-434
We isolated the small subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO SSu) from a fern,Asplenium cataractarum and determined its 34 N-terminal amino acid sequence. We obtained a cDNA clone that contains the entire coding region of
the SSu from the same fern species, using synthetic oligonucleotide probes derived from the above amino acid sequence. It
contains a 525 bp open reading frame capable of coding for a polypeptide with 174 amino acids, 31 bp 5′-and 206 bp 3′-noncoding
regions. It was also elucidated that the precursor to the SSu contains a transit peptide of 53 amino acid residues and a mature
protein of 121 residues. We compared the deduced amino acid sequence of the fern SSu with those of 11 other vascular plant
species (including gymnosperms, monocots and dicots). As low as 55% homology was observed between those of a fern and seed
plants. Constancy of the amino acid substitution rate in RuBisCO SSu was supported by our relative rate test. Amino acid substitution
rate per year per site for RuBisCO SSu was calculated to be 0.81×10−9 assuming that the separation between pteridophytes and seed plants arose 380 million years ago. 相似文献
5.
Neuronal activity preceding directional and nondirectional cues in the premotor cortex of rhesus monkeys 总被引:1,自引:0,他引:1
Pre-cue activity, the neuronal modulation that precedes a predictable stimulus, was studied in the premotor cortex of three rhesus monkeys. In one condition, a directional cue dictated the timing and target of a forelimb movement. In another condition, a nondirectional cue provided identical timing information but did not indicate the target. Of 501 task-related neurons recorded in premotor cortex, 168 showed pre-cue activity. The onset time of pre-cue activity varied markedly from trial to trial and cell to cell, ranging from trial initiation to 4.8 sec later. No pre-cue activity reflected the direction of limb movement; thus, the data argue against the hypothesis that pre-cue activity reflects preparation for specific limb movements. A small number of cells showed greater pre-cue activity before directional than before nondirectional cues, and this difference may reflect anticipation of the cue's directional information. However, the vast majority (84%) of neurons lacked such differences. We therefore hypothesize that most pre-cue activity reflects or contributes to a facet of behavior common to the two conditions: anticipation of the time and/or nature of events. 相似文献
6.
Concanavalin A (Con A)-binding proteins obtained from solubilized synaptosomal membranes of bovine brain were analyzed by two-dimensional electrophoresis (2DE), and were identified by peroxidase conjugated Con A (Con A-peroxidase staining), after transfer from 2DE gel to nitrocellulose paper. The Con A-binding proteins were resolved up to 40 spots, ranging in isoelectric points (pI) from 4.5 to 8.0 and molecular weight (MW) from 10 kDa to 120 kDa. Most of the Con A-binding proteins were streaked across a pH gradient and/or exhibited as multiple spots, indicating broad charge and molecular weight heterogeneity. The presence of protein groups that showed high affinities for Con A were revealed. Most interesting group (named GP51), which consisted of seven spots separated horizontally in charge heterogeneity (pI5.85-7.5) with MW 51kDa, was characterized by its binding to an immobilized protein A gel. This implies that GP51 is related to immunoglobulins and/or GP51 may be a new member of the immunoglobulin supergene family. 相似文献
7.
Tanaka Kiyoshi; Suda Yoshiko; Kondo Noriaki; Sugahara Kiyoshi 《Plant & cell physiology》1985,26(7):1425-1431
The relationship between O3 tolerance and the chloroplast H2O2scavenging system (PS I 相似文献
8.
9.
Chemotaxonomy of Gibberella zeae with special reference to production of trichothecenes and zearalenone. 总被引:8,自引:7,他引:1 下载免费PDF全文
By adopting a single-spore isolation technique, 113 isolates of Gibberella zeae, the perfect stage of Fusarium graminearum, were isolated from rice stubbles in barley and wheat fields and tested for production of trichothecenes and zearalenone on rice grains. Of the isolates, 93% produced the trichothecenes, and they could be subdivided into two chemotaxonomic groups: nivalenol and fusarenon-X producers and deoxynivalenol and 3-acetyldeoxynivalenol producers. No cross production of these two types of trichothecenes was observed in these isolates. Zearalenone was detected in 68% of the isolates, but no clear relationship could be observed regarding its position with respect to the two chemotaxonomic groups. 相似文献
10.
Noriaki Inamura Saburo Sone Akio Okubo Eiji Kunishige Mie Nakanishi Takeshi Ogura 《Cancer immunology, immunotherapy : CII》1989,28(3):164-170
Summary Human blood monocytes were isolated by counter-flow centrifugal elutriation from healthy donors and these noncytotoxic monocytes were rendered tumoricidal to allogeneic melanoma (A375) cells by activation with a synthetic acyltripeptide (FK-565), as assessed by measuring release of [125I]iododeoxyuridine in 72 h. When monocytes were treated with FK-565 for 16 h, and then fixed with paraformaldehyde, they showed cytotoxicity to A375 melanoma cells. The fixed-monocyte-mediated cytotoxicity to A375 cells was induced by the synergistic actions of FK-565 and recombinant interferon- (rIFN-), but not other cytokines [rIFN-A, rIFN-, tumor necrosis factor (TNF), interleukin (IL)-2, -3 and -6]. For synergistic activation of monocytes with induction of a membrane-associated antitumor monokine, the monocytes had to be incubated first with rIFN- and then with FK-565. FK-565 also acted synergistically with rIFN- to stimulate monocytes to produce membrane-associated IL-1 activity, which induced C3H/HeJ thymocyte blastogenesis in response to phytohemagglutinin P. The tumoricidal and thymocytestimulating activities of the fixed monocytes were almost completely inhibited by a specific anti-(IL-1) antiserum, but not by a specific anti-(IL-1) antiserum or monoclonal anti-TNF antibody. These results suggest that membrane-associated IL-1 of human blood monocytes can be induced by two activation signals (rIFN- then FK-565) at their suboptimal concentrations.Abbreviations IL
interleukin
- IFN
interferon
- TNF
tumor necrosis factor 相似文献