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1.
The optimum conditions for using the method of radioimmunoprecipitation (RIP) for the detection of human immunodeficiency virus (HIV) in serum samples have been established. Out of several available cell lines persistently infected with HIV, specially selected line 17 has been chosen. The characteristic feature of this is the high and stable (under the conditions of prolonged cultivation) accumulation of virus-specific proteins in infected cells. The optimum conditions for making the test and its evaluation have also been established. The data of literature on the advantages of the method of RIP over such traditional methods as the enzyme immunoassay and immunoblotting have been confirmed. Thus, the presence of specific antibodies in several serum samples registered as false negative has been established. The intertypical reactivity of two serotypes of the virus, HIV-1 and HIV-2, has been studied. Cross reactivity of antibodies with respect to the HIV gene gag, but not with respect to viral glycoproteids, has been established. Ideas on the expediency and prospects of using RIP for the serological control of HIV infection are presented.  相似文献   
2.
The peroxisomal manganese superoxide dismutase (perMn‐SOD; EC 1.15.1.1) was purified to homogeneity for the first time from peroxisomes of pea ( Pisum sativum L.) leaves. Peroxisomes were isolated from pea leaves by sucrose density‐gradient centrifugation, and then perMn‐SOD was purified from these organelles by two purification steps involving anion‐exchange and gel‐filtration fast protein liquid chromatography. Pure peroxisomal Mn‐SOD had a specific activity of 2 880 units per mg protein and was purified 3 000‐fold, with a yield of about 7 µg enzyme per kg pea leaves. The relative molecular mass determined for perMn‐SOD was 92 000, and it was composed of four equal subunits of 27 kDa. Ultraviolet and visible absorption spectra of the enzyme showed two absorption maxima at 278 and 483 nm, respectively, and two shoulders at 290 and 542 nm. By isoelectric focusing (pH 5‐7), an isoelectric point of 5.53 was determined for perMn‐SOD. In immunoblot assays, purified Mn‐SOD was recognized by a polyclonal antibody against mitochondrial Mn‐SOD (mitMn‐SOD) from pea leaves. The amino acid sequence of the N‐terminal region of the purified peroxisomal enzyme was determined. A 100% identity was found with the mitMn‐SOD from pea leaves, and high identities were also found with Mn‐SODs from other plant species.  相似文献   
3.
Although structurally similar to the natural plant hormone indol-3- acetic acid, auxin herbicides were developed for purposes other than growth, and have been successfully used in agriculture for the last 60 years. Concerted efforts are being made to understand and decipher the precise mechanism of action of IAA and synthetic auxins. Innumerable results need to be interconnected to resolve the puzzle of auxin biology and action mode of auxin herbicides. To date, different breakthroughs are providing more insights into the process of plant-herbicide interactions. Here we highlight some of the latest findings on how the 2,4-dichlorophenoxyacetic acid damages susceptible broadleaf plants, emphasizing the role of ROS as a downstream component of the auxin signal transduction under herbicide treatment.  相似文献   
4.
Peroxisomes are subcellular respiratory organelles which contain catalase and H2O2-producing flavin oxidases as basic enzymatic constituents. These organelles have an essentially oxidative type of metabolism and have the potential to carry out different important metabolic pathways. In recent years the presence of different types of superoxide dismutase (SOD) have been demonstrated in peroxisomes from several plant species, and more recently the occurrence of SOD has been extended to peroxisomes from human and transformed yeast cells. A copper,zinc-containing SOD from plant peroxisomes has been purified and partially characterized. The production of hydroxyl and superoxide radicals has been studied in peroxisomes. There are two sites of O2- production in peroxisomes: (1) in the matrix, the generating system being xanthine oxidase; and (2) in peroxisomal membranes, dependent on reduced nicotinamide adenine dinucleotide (NADH), and the electron transport components of the peroxisomal membrane are possibly responsible. The generation of oxygen radicals in peroxisomes could have important effects on cellular metabolism. Diverse cellular implications of oxyradical metabolism in peroxisomes are discussed in relation to phenomena such as cell injury, peroxisomal genetic diseases, peroxisome proliferation and oxidative stress, metal and salt stress, catabolism of nucleic acids, senescence, and plant pathogenic processes.  相似文献   
5.
Cadmium causes the oxidative modification of proteins in pea plants   总被引:23,自引:0,他引:23  
In pea (Pisum sativum L.) leaves from plants grown in the presence of 50 µm CdCl2 the oxidative production of carbonyl groups in proteins, the rate of protein degradation and the proteolytic activity were investigated. In leaf extracts the content of carbonyl groups measured by derivatization with 2,4‐dinitrophenylhydrazine (DNPH), was two‐fold higher in plants treated with Cd than in control plants. The identification of oxidized proteins was carried out by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis of proteins derivatized with DNPH and immunochemical detection with an antibody against DNPH. The intensity of the reactive bands was higher in plants exposed to Cd than in controls. By using different antibodies some of the oxidized proteins were identified as Rubisco, glutathione reductase, manganese superoxide dismutase, and catalase. The incubation of leaf crude extracts with increasing H2O2 concentrations showed a progressive enhancement in carbonyl content and the pattern of oxidized proteins was similar to that found in Cd‐treated plants. Oxidized proteins were more efficiently degraded, and the proteolytic activity increased 20% due to the metal treatment. In peroxisomes purified from pea leaves a rise in the carbonyl content similar to that obtained in crude extracts from Cd‐treated plants was observed, but the functionality of the peroxisomal membrane was not apparently affected by Cd. Results obtained demonstrate the participation of both oxidative stress, probably mediated by H2O2, and proteolytic degradation in the mechanism of Cd toxicity in leaves of pea plants, and they appear to be involved in the Cd‐induced senescence previously reported in these plants.  相似文献   
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7.

Background  

The influenza A virus is an important infectious cause of morbidity and mortality in humans and was responsible for 3 pandemics in the 20th century. As the replication of the influenza virus is based on its host's machinery, codon usage of its viral genes might be subject to host selection pressures, especially after interspecies transmission. A better understanding of viral evolution and host adaptive responses might help control this disease.  相似文献   
8.
Background Peroxisomes are highly dynamic, metabolically active organelles that used to be regarded as a sink for H2O2 generated in different organelles. However, peroxisomes are now considered to have a more complex function, containing different metabolic pathways, and they are an important source of reactive oxygen species (ROS), nitric oxide (NO) and reactive nitrogen species (RNS). Over-accumulation of ROS and RNS can give rise oxidative and nitrosative stress, but when produced at low concentrations they can act as signalling molecules.Scope This review focuses on the production of ROS and RNS in peroxisomes and their regulation by antioxidants. ROS production is associated with metabolic pathways such as photorespiration and fatty acid β-oxidation, and disturbances in any of these processes can be perceived by the cell as an alarm that triggers defence responses. Genetic and pharmacological studies have shown that photorespiratory H2O2 can affect nuclear gene expression, regulating the response to pathogen infection and light intensity. Proteomic studies have shown that peroxisomal proteins are targets for oxidative modification, S-nitrosylation and nitration and have highlighted the importance of these modifications in regulating peroxisomal metabolism and signalling networks. The morphology, size, number and speed of movement of peroxisomes can also change in response to oxidative stress, meaning that an ROS/redox receptor is required. Information available on the production and detection of NO/RNS in peroxisomes is more limited. Peroxisomal homeostasis is critical for maintaining the cellular redox balance and is regulated by ROS, peroxisomal proteases and autophagic processes.Conclusions Peroxisomes play a key role in many aspects of plant development and acclimation to stress conditions. These organelles can sense ROS/redox changes in the cell and thus trigger rapid and specific responses to environmental cues involving changes in peroxisomal dynamics as well as ROS- and NO-dependent signalling networks, although the mechanisms involved have not yet been established. Peroxisomes can therefore be regarded as a highly important decision-making platform in the cell, where ROS and RNS play a determining role.  相似文献   
9.
Recent studies of mitochondrial DNA (mtDNA) variation in mammals and Drosophila have shown an excess of amino acid variation within species (replacement polymorphism) relative to the number of silent and replacement differences fixed between species. To examine further this pattern of nonneutral mtDNA evolution, we present sequence data for the ND3 and ND5 genes from 59 lines of Drosophila melanogaster and 29 lines of D. simulans. Of interest are the frequency spectra of silent and replacement polymorphisms, and potential variation among genes and taxa in the departures from neutral expectations. The Drosophila ND3 and ND5 data show no significant excess of replacement polymorphism using the McDonald-Kreitman test. These data are in contrast to significant departures from neutrality for the ND3 gene in mammals and other genes in Drosophila mtDNA (cytochrome b and ATPase 6). Pooled across genes, however, both Drosophila and human mtDNA show very significant excesses of amino acid polymorphism. Silent polymorphisms at ND5 show a significantly higher variance in frequency than replacement polymorphisms, and the latter show a significant skew toward low frequencies (Tajima's D = -1.954). These patterns are interpreted in light of the nearly neutral theory where mildly deleterious amino acid haplotypes are observed as ephemeral variants within species but do not contribute to divergence. The patterns of polymorphism and divergence at charge-altering amino acid sites are presented for the Drosophila ND5 gene to examine the evolution of functionally distinct mutations. Excess charge-altering polymorphism is observed at the carboxyl terminal and excess charge-altering divergence is detected at the amino terminal. While the mildly deleterious model fits as a net effect in the evolution of nonrecombining mitochondrial genomes, these data suggest that opposing evolutionary pressures may act on different regions of mitochondrial genes and genomes.   相似文献   
10.
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