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91.
Optically active aminonaphthols derivatives are obtained by condensation of 2-naphthol, substituted benzaldehyde, and (S)-methylbenzylamine under mild conditions, without side products. Their absolute configurations are determined by X-ray crystallographic analysis. The addition of diethylzinc to aromatic aldehydes is considerably accelerated by the presence of a catalytic amount of crystalline to give, after hydrolysis, the corresponding 1-phenylpropanol in good enantiomeric purity, as determined by CD-HPLC analysis as HTPS (high-throughput screening). 相似文献
92.
Amphiphilic beta-sheet cobra cardiotoxin targets mitochondria and disrupts its network 总被引:2,自引:0,他引:2
Recent advance in understanding the role of toxin proteins in controlling cell death has revealed that pro-apoptotic viral proteins targeting mitochondria contain amphiphilic alpha-helices with pore-forming properties. Herein, we describe that the pore-forming amphiphilic beta-sheet cardiotoxins (or cytotoxins, CTXs) from Taiwan cobra (Naja atra) also target mitochondrial membrane after internalization and act synergistically with CTX-induced cytosolic calcium increase to disrupt mitochondria network. It is suggested that CTX-induced fragmentation of mitochondria play a role in controlling CTX-induced necrosis of myocytes and cause severe tissue necrosis in the victims. 相似文献
93.
Calcium and mitochondria 总被引:8,自引:0,他引:8
The literature suggests that the physiological functions for which mitochondria sequester Ca(2+) are (1). to stimulate and control the rate of oxidative phosphorylation, (2). to induce the mitochondrial permeability transition (MPT) and perhaps apoptotic cell death, and (3). to modify the shape of cytosolic Ca(2+) pulses or transients. There is strong evidence that intramitochondrial Ca(2+) controls both the rate of ATP production by oxidative phosphorylation and induction of the MPT. Since the results of these processes are so divergent, the signals inducing them must not be ambiguous. Furthermore, as pointed out by Balaban [J. Mol. Cell. Cardiol. 34 (2002 ) 11259-11271], for any repetitive physiological process dependent on intramitochondrial free Ca(2+) concentration ([Ca(2+)](m)), a kind of intramitochondrial homeostasis must exist so that Ca(2+) influx during the pulse is matched by Ca(2+) efflux during the period between pulses to avoid either Ca(2+) buildup or depletion. In addition, mitochondrial Ca(2+) transport modifies both spatial and temporal aspects of cytosolic Ca(2+) signaling. Here, we look at the amounts of Ca(2+) necessary to mediate the functions of mitochondrial Ca(2+) transport and at the mechanisms of transport themselves in order to set up a hypothesis about how the mechanisms carry out their roles. The emphasis here is on isolated mitochondria and on general mitochondrial properties in order to focus on how mitochondria alone may function to fulfill their physiological roles even though the interactions of mitochondria with other organelles, particularly with endoplasmic and sarcoplasmic reticulum [Sci. STKE re1 (2004) 1-9], may also influence this story. 相似文献
94.
Malondialdehyde (MDA) is a well known inducer of carbonyl stress in a variety of human cells, however, its effects on human
bone marrow mesenchymal stem cells (hMSCs) have not been documented. In this study, the effects of MDA concentration on the
growth rate and proliferation of hMSCs in vitro were assessed. Under high concentrations of MDA, the cell count was decreased and the population doubling time (PDT) was
lengthened. Flow cytometry (FCM) demonstrated that MDA triggered cells to undergo apoptosis, in parallel with the findings
in MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay which showed that it can also impair cellular
viability. Surprisingly, FCM also determined that the percentage of hMSCs in G2/M-and S-phases also increased in a dose-dependent manner with respect to MDA concentration. These results strongly suggest
that even though hMSCs were severely impaired by high concentrations of MDA, they were still able to send signals that resulted
in accelerated cellular proliferation process. This study provided important insights on how carbonyl stress affects cell
cycle and proliferation of hMSCs.
__________
Translated from Journal of Natural Science of Hunan Normal University, 2005, 28 (2) [译自: 湖南师范大学自然科学报, 2005,28(2)] 相似文献
95.
FENG ZHU HE TANG XIN LV JIAN CHENG HUANG‐FAN XIE HONG‐HUI LIN 《Plant, cell & environment》2012,35(11):1983-1997
The effects of potassium cyanide (KCN) pretreatment on the response of cucumber (Cucumis sativus L.) plants to salt, polyethylene glycol (PEG) and cold stress were investigated in the present study. Here, we found that KCN pretreatment improved cucumber seedlings tolerance to stress conditions with maximum efficiency at a concentration of 20 µM. The results showed that pretreatment with 20 µM KCN alleviated stress‐induced oxidative damage in plant cells and clearly induced the activity of alternative oxidase (AOX) and the ethylene production. Furthermore, the structures of thylakoids and mitochondria in the KCN‐pretreated seedlings were less damaged by the stress conditions, which maintained higher total chlorophyll content, photosynthetic rate and photosystem II (PSII) proteins levels than the control. Importantly, the addition of the AOX inhibitor salicylhydroxamic acid (1 mm ; SHAM) decreased plant resistance to environmental stress and even compromised the cyanide (CN)‐enhanced stress tolerance. Therefore, our findings provide a novel role of CN in plant against environmental stress and indicate that the CN‐enhanced AOX might contribute to the reactive oxygen species (ROS) scavenging and the protection of photosystem by maintaining energy charge homoeostasis from chloroplast to mitochondria. 相似文献
96.
The four gases, nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H2S) and hydrogen cyanide (HCN) all readily inhibit oxygen consumption by mitochondrial cytochrome oxidase. This inhibition
is responsible for much of their toxicity when they are applied externally to the body. However, recently these gases have
all been implicated, to greater or lesser extents, in normal cellular signalling events. In this review we analyse the chemistry
of this inhibition, comparing and contrasting mechanism and discussing physiological consequences. The inhibition by NO and
CO is dependent on oxygen concentration, but that of HCN and H2S is not. NO and H2S are readily metabolised by oxidative processes within cytochrome oxidase. In these cases the enzyme may act as a physiological
detoxifier of these gases. CO oxidation is much slower and unlikely to be as physiologically important. The evidence for normal
physiological levels of these gases interacting with cytochrome oxidase is equivocal, in part because there is little robust
data about their steady state concentrations. A reasonable case can be made for NO, and perhaps CO and H2S, inhibiting cytochrome oxidase in vivo, but endogenous levels of HCN seem unlikely to be high enough. 相似文献
97.
The H-bonded complex of ATP with Arg 34 of Zn2+ finger I of poly-ADP-ribose polymerase-1 (PARP-1) determines trans-oligo-ADP-ribosylation from NAD+ to proteins other than PARP-1. This mechanism was tested in lysolecithin fractions of non-malignant and cancer cells separately and after their recombination. Cellular PARP-1 activity was recovered when the centrifugal sediment was recombined with the supernatant fraction containing cellular ADP-ribose oligomer acceptor proteins. Combination of the matrix fraction (Mx) of cancer cells (lacking OXPHOS) with its supernatant had the same PARP-1 activity as the Mx alone. The supernatant of non-malignant cells was replaced by glycolytic enzymes as ADP-ribose acceptor. The hexokinase activity of the supernatant increased when OXPHOS of intact cells was uncoupled by carbonyl cyanide 4-(trifluoro methoxy) phenylhydrazone. trans-ADP-ribosylation was demonstrated by polyacrylamide gel electrophoresis. 相似文献
98.
Susann Richert Nancy B Wehr Earl R Stadtman Rodney L Levine 《Archives of biochemistry and biophysics》2002,397(2):430-432
The oxidative modification of proteins by reactive species, especially reactive oxygen species, is implicated in the etiology or progression of a panoply of disorders and diseases. For the most part, oxidatively modified proteins are not repaired and must be removed by proteolytic degradation. The level of these modified molecules can be quantitated by measurement of the protein carbonyl content, which has been shown to increase in a variety of diseases and processes, most notably during aging. However, these studies have required invasive techniques to obtain cells for analysis. We examined the possibility that desquamating skin cells (corneocytes) would also show an age-related increase in protein carbonyl content, thus providing a noninvasive method for assessing biological age. This was not the case, as we found no age-dependent relationship in the protein carbonyl content of skin cells from volunteers aged 20 to 79 years. 相似文献
99.
Miyakawa Shin Cleaves H. James Miller Stanley L. 《Origins of life and evolution of the biosphere》2002,32(3):209-218
A wide variety of pyrimidines and purineswere identified as products of a dilute frozen ammoniumcyanide solution that had been held at –78°C for 27 years.This demonstrates that both pyrimidines and purines couldhave been produced on the primitive earth in a short time byeutectic concentration of HCN, even though the concentrationof HCN in the primitive ocean may have been low. We suggestthat eutectic freezing is the most plausible demonstratedmechanism by which HCN polymerizations could have producedbiologically important prebiotic compounds. 相似文献
100.
Tindaro M. Giardina 《BBA》2008,1777(2):118-129
Uncoupling protein-2 (UCP2) is a member of the inner mitochondrial membrane anion-carrier superfamily. Although mRNA for UCP2 is widely expressed, protein expression is detected in only a few cell types, including macrophages. UCP2 functions by an incompletely defined mechanism, to reduce reactive oxygen species production during mitochondrial electron transport. We observed that the abundance of UCP2 in macrophages increased rapidly in response to treatments (rotenone, antimycin A and diethyldithiocarbamate) that increased mitochondrial superoxide production, but not in response to superoxide produced outside the mitochondria or in response to H2O2. Increased UCP2 protein was not accompanied by increases in ucp2 gene expression or mRNA abundance, but was due to enhanced translational efficiency and possibly stabilization of UCP2 protein in the inner mitochondrial membrane. This was not dependent on mitochondrial membrane potential. These findings extend our understanding of the homeostatic function of UCP2 in regulating mitochondrial reactive oxygen production by identifying a feedback loop that senses mitochondrial reactive oxygen production and increases inner mitochondrial membrane UCP2 abundance and activity. Reactive oxygen species-induction of UCP2 may facilitate survival of macrophages and retention of function in widely variable tissue environments. 相似文献