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991.
HSP68 — a DnaK-like heat-stress protein of plant mitochondria 总被引:1,自引:0,他引:1
D. Neumann M. Emmermann J.-M. Thierfelder U. zur Nieden M. Clericus H.-P. Braun L. Nover U. K. Schmitz 《Planta》1993,190(1):32-43
A 68-kDa heat-stress protein (HSP68) has been purified from cell-suspension cultures of tomato (Lycopersicon peruvianum L.). Antibodies raised against HSP68 cross-react with the Escherichia coli heat-stress protein DnaK. HSP68 was found to be a hydrophilic, ATP-binding protein. Immunological analysis of subcellular fractions and immunogold-labelling of ultrathin sections showed consistently that HSP68 is localized in the mitochondrial matrix. In-vitro translation experiments indicated that HSP68 is synthesized as a precursor protein. Immunoscreening of cDNA libraries from tomato and potato (Solanum tuberosum L.) led to the isolation of corresponding cDNA clones. The deduced amino-acid sequences show strong relationships to the DnaK-like proteins from bacteria and organelles of eukaryotic cells. The protein HSP68 is constitutively expressed, but its synthesis is increased during heat stress in all cells of higher plantes investigated so far.Abbreviations HSP
heat-stress protein
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
This work was supported by the Deutsche Forschungsgemeinschaft. 相似文献
992.
All living cells, when exposed to elevated temperatures, undergo physiological changes which result in the expression of a
specific set of heat shock proteins. Study of the possible physiological changes in adult and embryonic rat liver cells indicated
a change in intracellular pH upon heat shock. Using 2′, 7′-bis (2-carboxyethyl)-5 (and -6) carboxyfluorescein acetoxymethyl
ester, we demonstrate here that the intracellular pH of adult and embryonic liver cells is different and that there is an
increase in relative fluorescence intensity in both adult and embryonic cells upon heat shock, which corresponds to about
0.2 to 0.3 pH units. We also show that in addition to heat, some of the inducers of heat shock like response in many systems
also induce a change in intracellular pH and induce heat shock proteins at 37°C in fetal liver cells. The possible mechanisms
of induction of heat shock proteins during heat shock and in the presence of inducers at normal temperature are discussed. 相似文献
993.
Comparisons of diverse plant species reveal that only grasses show drastically reduced levels of ubiquitin monomer in mature pollen 总被引:3,自引:0,他引:3
Ubiquitin is a ubiquitous protein involved in targeting proteins for degradation. Maize pollen was previously reported (Callis and Bedinger 1994) to show extremely low levels of ubiquitin monomer, and developmental significance was attributed to this surprising feature of maize pollen. However, we had previously shown (Muschietti et al. 1994) that tomato pollen had high levels of ubiquitin monomer. Here we show that pollen from most plant families has high levels of ubiquitin monomer. Most grasses tested show reduced levels of ubiquitin monomer, but some maize inbred lines have higher levels of ubiquitin monomer than other inbreds. There was no correlation between the level of ubiquitin monomer and either the monocotyledonous or tri-cellular condition of grass pollen or the dehydrated condition of mature pollen. Since many aspects of pollen development (i.e., wall formation, microspore mitosis, synthesis and storage of mRNAs and proteins, carbohydrates and lipids, dehydration at maturity) are stereotypical among all plant families, the reduced level of ubiquitin monomer in pollen of many grasses cannot be crucial for any feature of normal pollen development. 相似文献
994.
We report on the stress-independent, tissue-specific expression of the heat-stress protein HSP17 in developing seeds of different plant species and on its intracellular localization. Though HSP17 expression during seed development seems to be a general phenomenon, the isoform patterns, the relative amounts in embryonic tissues and the intracellular localization show species-specific variations. In contrast to the results on the stressinduced protein forming large cytoplasmic aggregates (heat stress granules) the developmentally expressed HSP17 is mainly found in nuclei. But in addition, a considerable part is also detected in protein bodies of mature seeds of Lycopersicon esculentum and Vicia faba, but not of Zea mays. The mechanism of this transition into the vacuolar compartment remains to be investigated.Abbreviations 2D
two-dimensional
- HSE
heat shock elements
- HSP
heat stress protein 相似文献
995.
996.
Conditioning Heat Stress Reduces Excitotoxic and Apoptotic Components of Oxygen-Glucose Deprivation-Induced Neuronal Death In Vitro 总被引:2,自引:2,他引:0
B. Joy Snider Doug Lobner Kelvin A. Yamada Dennis W. Choi 《Journal of neurochemistry》1998,70(1):120-129
Abstract: We investigated the effects of sublethal heat stress in murine cortical cell cultures exposed to combined oxygen and glucose deprivation. Pretreatment with sublethal heat stress mildly attenuated the widespread neuronal death induced a day later by 30–60 min of oxygen-glucose deprivation. Heat stress also blunted the increase in extracellular glutamate concentrations induced by the oxygen-glucose deprivation, as well as the neuronal death and 45 Ca2+ uptake induced by exogenous addition of NMDA, although no reduction was seen in neuronal death caused by exogenous kainate or in NMDA-induced whole-cell currents. However, arguing against the idea that the neuroprotective effect of heat stress against neuronal death was exclusively due to reduction of excitotoxicity was the finding that heat stress also reduced the neuronal apoptosis induced by oxygen-glucose deprivation in the presence of glutamate antagonists. This antiapoptotic effect was specific in that heat stress did not reduce neuronal vulnerability to staurosporine-induced apoptosis. Whereas heat stress transiently suppressed protein synthesis, achieving comparable protein synthesis inhibition with cycloheximide did not reproduce the neuroprotective effects of heat stress. These studies suggest that a conditioning heat stress is able to attenuate both the excitotoxic and the apoptotic components of oxygen-glucose deprivation-induced neuronal death in vitro, by mechanisms independent of protein synthesis reduction. 相似文献
997.
T. Mizushima Y. Ohtsuka H. Mori T. Miki K. Sekimizu 《Molecular & general genetics : MGG》1996,253(3):297-302
We report here that in Escherichia coli, the anti-bacterial agent nalidixic acid induces transient stabilization and increased synthesis of σ32, accompanied by the induction of heat shock proteins (Dnak and GroEL proteins). The induction of heat shock proteins, increased
synthesis of σ32, and stabilization of σ32 observed on treatment of wild-type cells with nalidixic acid were not observed in a nalA26 mutant, a strain that is resistant to nalidixic acid as the result of a mutation in the gyrA gene. Not only oxolinic acid, but also novobiocin, whose targets are the A and B subunits of DNA gyrase, respectively, also
induced stabilization and increased synthesis of σ32. Thus, inhibition of the activity of DNA gyrase may cause stabilization and increased synthesis of σ32, resulting in turn in induction of heat shock proteins.
Received: 11 July 1996 / Accepted: 16 August 1996 相似文献
998.
Takao Kaneko Tohru Mizushima Yoshihisa Ohtsuka Kenji Kurokawa Kazuhiro Kataoka Takeyoshi Miki Kazuhisa Sekimizu 《Molecular & general genetics : MGG》1996,250(5):593-600
We examined the influence of overexpression of LetD (CcdB) protein, an inhibitor of DNA gyrase encoded by the F factor ofEscherichia coli, on DNA supercoiling and induction of heat shock proteins. Cells were transformed with a plasmid carrying the structural gene for LetD protein under control of thetac promoter, and LetD protein was induced by adding isopropyl-d-thiogalactopyranoside (IPTG) to the culture medium. Analysis by agarose gel electrophoresis in the presence of chloroquine revealed relaxation of plasmid DNA in cells depending on the concentration of IPTG employed for induction. Protein pulse-labeling experiments with [35S]methionine and cysteine revealed that synthesis of DnaK and GroEL proteins was also induced by IPTG, and concentrations necessary for DNA relaxation and induction of the heat shock proteins were much the same. Expression of mutant LetD protein lacking two amino acid residues at the C-terminus induced neither DNA relaxation nor the synthesis of DnaK and GroEL proteins. Induction of wild-type LetD protein but not mutant LetD protein markedly enhanced synthesis of
32. We interpret these results to mean that DNA relaxation in cells caused by the expression of LetD protein induces heat shock proteins via increased synthesis of
32. 相似文献
999.
1000.
R. J. Campbell H. F. Linskens 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1984,68(3):259-264
Summary Detached pistils of the clonal variety, Lilium longiflorum Aral No. 5, were submerged before pollination in 50°C water for 0, 1, 2, 3, 4, 5, 6 or 7 min and then immediately compatibly and incompatibly pollinated. Incompatibility, as indicated by pollen tube length after 48 h at 23.5°C, was eliminated by a 1–2 min submersion while compatibility was removed by a 4–5 min one. The window of incubation temperatures at which incompatible and compatible pollen tubes are clearly differentiated occurred between 15 and 30°C. 相似文献