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21.
Heat-shock proteins induce heavy-metal tolerance in higher plants 总被引:14,自引:0,他引:14
Cell cultures of Lycopersicon peruvianum L. stressed with CdSO4 (10–3M) show typical changes in the ultrastructure, starting with the plasmalemma and later on extending to the endoplasmic reticulum and the mitochondrial envelope. Part of the membrane material is extruded, with the formation of osmiophilic droplets which increase in size and number during the stress period. After 4 h, about 20 of the cells are dead. A short heat stress preceeding the heavy-metal stress induces a tolerance effect by preventing the membrane damage. The cells show a normal ultrastructure with one exception: cytoplasmic heat-shock granules are formed. This protective effect can be abolished by cycloheximide. Cadmium uptake is not markedly influenced by the heat stress. Cadmium is found together with sulfur in small deposits in the vacuoles of stressed cells. The precipitates contain an excess of sulfur, evidently due to the stress-induced formation of phytochelatins. The role in heavy-metal tolerance of heat-shock proteins in the plasmalemma (HSP70) and in cytoplasmic heat-stress granules (HSP17, HSP70) is discussed.Abbreviations EDX
energy dispersive analysis of X-rays
- ESI
electron-spectroscopic imaging
- HM
heavy metal
- HSG
heat-stress granules
- HSP
heat-shock protein
- MNDO
modified neglect of diatomic overlap
This work was supported by the Ministerium für Wissenschaft und Forschung des Landes Sachsen-Anhalt and the Deutsche Forschungsgemeinschaft. 相似文献
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Vegetation History and Archaeobotany - In this paper we present the analysis of archaeobotanical material retrieved by means of flotation from well-secured features during recent excavation work... 相似文献
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Background
The nonsteroidal anti-inflammatory drug (NSAID), indomethacin (Indo), has a large number of divergent biological effects, the molecular mechanism(s) for which have yet to be fully elucidated. Interestingly, Indo is highly amphiphilic and associates strongly with lipid membranes, which influence localization, structure and function of membrane-associating proteins and actively regulate cell signaling events. Thus, it is possible that Indo regulates diverse cell functions by altering micro-environments within the membrane. Here we explored the effect of Indo on the nature of the segregated domains in a mixed model membrane composed of dipalmitoyl phosphatidyl-choline (di16∶0 PC, or DPPC) and dioleoyl phosphatidyl-choline (di18∶1 PC or DOPC) and cholesterol that mimics biomembranes.Methodology/Principal Findings
Using a series of fluorescent probes in a fluorescence resonance energy transfer (FRET) study, we found that Indo induced separation between gel domains and fluid domains in the mixed model membrane, possibly by enhancing the formation of gel-phase domains. This effect originated from the ability of Indo to specifically target the ordered domains in the mixed membrane. These findings were further confirmed by measuring the ability of Indo to affect the fluidity-dependent fluorescence quenching and the level of detergent resistance of membranes.Conclusion/Significance
Because the tested lipids are the main lipid constituents in cell membranes, the observed formation of gel phase domains induced by Indo potentially occurs in biomembranes. This marked Indo-induced change in phase behavior potentially alters membrane protein functions, which contribute to the wide variety of biological activities of Indo and other NSAIDs. 相似文献27.
Naeem A. Ali Alice A. Gaughan Charles G. Orosz Chris P. Baran Sara McMaken Yijie Wang Timothy D. Eubank Melissa Hunter Frank J. Lichtenberger Nicholas A. Flavahan Jack Lawler Clay B. Marsh 《PloS one》2008,3(4)
Latency Associated Peptide (LAP) binds TGF-β1, forming a latent complex.
Currently, LAP is presumed to function only as a sequestering agent for active
TGF-β1. Previous work shows that LAP can induce epithelial cell
migration, but effects on leukocytes have not been reported. Because of the
multiplicity of immunologic processes in which TGF-β1 plays a role, we
hypothesized that LAP could function independently to modulate immune responses.
In separate experiments we found that LAP promoted chemotaxis of human monocytes
and blocked inflammation in vivo in a murine model of the
delayed-type hypersensitivity response (DTHR). These effects did not involve
TGF-β1 activity. Further studies revealed that disruption of specific
LAP-thrombospondin-1 (TSP-1) interactions prevented LAP-induced responses. The
effect of LAP on DTH inhibition depended on IL-10. These data support a novel
role for LAP in regulating monocyte trafficking and immune modulation. 相似文献
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BACKGROUND: Myiasis is the infestation of tissues and organs by dipteran larvae and is endemic in tropical areas. Diagnosis usually is made by demonstration of a larva or larvae in infected tissue, generally recognizable to the naked eye. In our case, diagnosis was based on fine needle aspiration cytology (FNAC). CASE: A 59-year-old female patient with a painful neck mass was examined at an otorhinolaryngologic department after symptoms for several weeks. The lesion was found to be an absceding lymphadenitis, based on clinical symptoms, palpation and imaging (ultrasound and computed tomography). The lesion did not improve with repeated courses of antibiotics, so surgery was performed. Pus cultures collected after incision were negative, leaving origin of the inflammation undetermined. Smears from FNA of the residual mass demonstrated a worm-like pathogen alien to most European pathologists' experience. The pathogen was identified as a dipteran larva, leading to accurate etiologic diagnosis of myiasis. More scrupulous examination of the patient's history revealed she had spent her vacation in Australia, where she probably acquired the infection. CONCLUSION: Our case demonstrates the growing importance of the pathology of infectious diseases. One reason for this may be the ever-increasing possibility, frequency and distance of travel. 相似文献
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D. Neumann O. Lichtenberger W. Schwieger U. zur Nieden 《Plant biology (Stuttgart, Germany)》1997,110(4):282-290
Silicon was localized in some dicotyledons (Minuartia verna, Silene cucubalus, Thlaspi coerulescens, Viola calaminaria, Nicotiana tabacum, Pisum sativum) by analytical transmission electron microscopy as apoplastic crystalline inclusions of SiO2 in intercellular spaces of the leaf parenchyma, between cell wall and plasma membrane and inside the vacuoles. Ca-silicate, and in some plants Sn-silicate, forms the peripheral parts of the crystalline inclusions. These unstable compounds are converted spontaneously in the plant cells into the more stable SiO2, which forms the central part of all crystalline inclusions. The function of silicon in these plants is discussed. 相似文献
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M. J. Lichtenberger 《Biotechnic & histochemistry》1983,58(4):185-188
Staining G-bands of chromosomes can be carried out in 2 minutes using a mixture of Giemsa solution with a special diluting preparation. The staining is completely reversible without any damage to the chromosomes. Moreover, an improved method for staining Q-bands with atebrin and mounting the preparation in sucrose is described. The whole process is performed in one minute and the preparations keep for weeks at laboratory temperature. 相似文献