摘要 :
The climatic changes pose important threats to agriculture. Plants are sessile organisms and need to cope with different environmental conditions throughout their lifespan. Most responses involve different signaling molecules, inc...
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The climatic changes pose important threats to agriculture. Plants are sessile organisms and need to cope with different environmental conditions throughout their lifespan. Most responses involve different signaling molecules, including reactive oxygen species (ROS). Due to their high reactivity, ROS are also an oxidative threat to the cell. Consequently, plant cells display elaborated defenses against oxidative stress. The ascorbate-glutathione cycle is the main antioxidant pathway in photosynthetic organisms and is composed by the enzymes ascorbate peroxidase (APX), monodehydroascorbate reductase (MDAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR). Here, the APX, MDAR, DHAR and GR genes from castor bean, cassava, jatropha and rubber tree were identified and classified. This classification allowed the prediction of their subcellular localization within plant cells, such as cytosol, peroxisomes, chloroplasts, and mitochondria. Our analysis also contributes to understanding the evolutionary history of these genes. The expression pattern of ascorbate-glutathione cycle genes in castor bean submitted to drought reveals changes in leaves and roots. Altogether, these data contribute to uncovering the regulation of ROS metabolism during stress response in castor bean, which is highly tolerant to drought.
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Ascorbate peroxidases (APXs) are heme peroxidases involved in the control of hydrogen peroxide levels and signal transduction pathways related to development and stress responses. Here, a total of 238 APX , 30 APX-related ( APX-R ...
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Ascorbate peroxidases (APXs) are heme peroxidases involved in the control of hydrogen peroxide levels and signal transduction pathways related to development and stress responses. Here, a total of 238 APX , 30 APX-related ( APX-R ), and 34 APX-like ( APX-L ) genes were identified from 24 species from the Poaceae family. Phylogenetic analysis of APX indicated five distinct clades, equivalent to cytosolic ( cAPX ), peroxisomal ( pAPX ), mitochondrial ( mitAPX ), stromal ( sAPX ), and thylakoidal ( tAPX ) isoforms. Duplication events contributed to the expansion of this family and the divergence times. Different from other APX isoforms, the emergence of Poaceae mitAPXs occurred independently after eudicot and monocot divergence. Our results showed that the constitutive silencing of mitAPX genes is not viable in rice plants, suggesting that these isoforms are essential for rice regeneration or development. We also obtained rice plants silenced individually to sAPX isoforms, demonstrating that, different to plants double silenced to both sAPX and tAPX or single silenced to tAPX previously obtained, these plants do not show changes in the total APX activity and hydrogen peroxide content in the shoot. Among rice plants silenced to different isoforms, plants silenced to cAPX showed a higher decrease in total APX activity and an increase in hydrogen peroxide levels. These results suggest that the cAPXs are the main isoforms responsible for regulating hydrogen peroxide levels in the cell, whereas in the chloroplast, this role is provided mainly by the tAPX isoform. In addition to broadening our understanding of the core components of the antioxidant defense in Poaceae species, the present study also provides a platform for their functional characterization.
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摘要 :
Background: "Roberto Costa?￠a??a?￠s Biotherapics" are homeopathic remedies prepared from intact microorganisms which have been proposed for treatment of diseases like influenza. Aim: This study aimed to compare the biochemical e...
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Background: "Roberto Costa?￠a??a?￠s Biotherapics" are homeopathic remedies prepared from intact microorganisms which have been proposed for treatment of diseases like influenza. Aim: This study aimed to compare the biochemical effects, in MDCK cells and RAW-264-7 macrophages, of biotherapics prepared from intact influenza virus diluted in water as well as from a sample of the same virus inactivated by ethanol 70% (v / v), both in the homeopathic potencies of 12x and 30x. Water 30x, non-dynamized water and cells without treatment (control cells) were used as control. Methodology: Treatments were performed by incubating MDCK cells with DMEM medium added in a 1:10 ratio for 6 times (3 different aliquots per day) or 18 times (up to 4 aliquots per day) in each experimental situation. Each aliquot was added with an interval of at least 2 hours. After that, the mitochondrial activity of MDCK cells was analyzed by MTT assay. The effects of treatments with intact biotherapics on MDCK cells respiratory parameters were studied using high resolution respirometry (Oroboros Oxygraph-O2K). RAW-264-7 macrophages were treated with intact and inactivated biotherapic 30x (4 treatments, 24 hours) to verify the nitric oxide production. These macrophages were also submitted to MTT assay. Results: Both biotherapic preparations 1x (intact and inactivated virus sample) were analyzed by transmission electronic microscopy. The presence of virus particles was detected when water was used as solvent. The use of ethanol as biotherapic solvent induced complete virus lysis. There was no alteration in cell osmolarity revealed by neutral red assay, when 10% of each test solution was used. Cellular viability analyzed by MTT method increased when MDCK cells were treated with 18 stimuli of inactivated biotherapic 30x when compared to intact biotherapic 30x (p0.05) were detected when these cells were compared to control cells. The maximum respiratory capacity of MDCK cells increased after treatment with 18 stimuli of intact biotherapic 30x when compared to control cells. However, no statistically significant differences (p>0.05) induced by biotherapics in macrophage cells were observed by MTT and nitric oxide assays. Moreover, a reduction in nitric oxide was observed in macrophages treated with dynamized water when compared to control cells. Conclusions: These results indicate that the method of biotherapic compounding (intact or inactivated virus as starting point) can modify the cellular parameters with the tendency to increase cellular response with longer treatments and higher potencies.
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