Up-regulation Of Oxidative Stress Genes Research Articles

İsatinin HepG2 ve AML12 hücre hatları üzerindeki moleküler etkilerinin araştırılması

Isatin is an indole-derived organic compound. It is a natural component of the Couroupita guianensis plant. It is also the metabolic derivative of the human body hormone adrenaline. Studies have shown the anti-tumoral effects of isatin derivatives. In this study, the cytotoxic effects of isatin on HepG2, a hepatocellular cancer cell line was investigated. Additionally, its cytotoxic and protective-proliferative effects on AML12, a healthy liver cell line was investigated. This evaluation was conducted using MTT, fluorescent staining, wound healing, and real-time polymerase chain reaction analyses. The IC50 values for 48 hours of isatin application were calculated as 186.23 µM for HepG2 and 7.05 mM for AML12. The analysis of wound healing and fluorescent staining at varying doses of HepG2 application revealed suppression of proliferation and triggered apoptosis in HepG2 cells. In contrast, AML12 cells exhibited promoted proliferation under similar conditions. Moreover, the observed upregulation of oxidative stress genes CuZn/Mn-SOD and mitochondrial apoptotic pathway genes Bax, cleaveled-Cas3, APAF1, and p53 in HepG2 cells contrasted with their decreased expression in AML12 cell lines. These results suggest the potential of natural isatin as a promising anti-cancer agent for liver cancer cell lines and as a protective supplement for healthy liver cells.

Phytohormones and induction of plant-stress tolerance and defense genes by seed and foliar inoculation with Azospirillum brasilense cells and metabolites promote maize growth

Azospirillum spp. are plant-growth-promoting bacteria used worldwide as inoculants for a variety of crops. Among the beneficial mechanisms associated with Azospirillum inoculation, emphasis has been given to the biological nitrogen fixation process and to the synthesis of phytohormones. In Brazil, the application of inoculants containing A. brasilense strains Ab-V5 and Ab-V6 to cereals is exponentially growing and in this study we investigated the effects of maize inoculation with these two strains applied on seeds or by leaf spray at the V2.5 stage growth—a strategy to relieve incompatibility with pesticides used for seed treatment. We also investigate the effects of spraying the metabolites of these two strains at V2.5. Maize growth was promoted by the inoculation of bacteria and their metabolites. When applied via foliar spray, although A. brasilense survival on leaves was confirmed by confocal microscopy and cell recovery, few cells were detected after 24 h, indicating that the effects of bacterial leaf spray might also be related to their metabolites. The major molecules detected in the supernatants of both strains were indole-3-acetic acid, indole-3-ethanol, indole-3-lactic acid and salicylic acid. RT-PCR of genes related to oxidative stress (APX1, APX2, CAT1, SOD2, SOD4) and plant defense (pathogenesis-related PR1, prp2 and prp4) was evaluated on maize leaves and roots. Differences were observed according to the gene, plant tissue, strain and method of application, but, in general, inoculation with Azospirillum resulted in up-regulation of oxidative stress genes in leaves and down-regulation in roots; contrarily, in general, PR genes were down-regulated in leaves and up-regulated in roots. Emphasis should be given to the application of metabolites, especially of Ab-V5 + Ab-V6 that in general resulted in the highest up-regulation of oxidative-stress and PR genes both in leaves and in roots. We hypothesize that the benefits of inoculation of Azospirillum on seeds or by leaf spray, as well as of leaf spraying of Azospirillum metabolites, are strongly correlated with the synthesis of phytohormones and by eliciting genes related to plant-stress tolerance and defense against pathogens.

Bemisia tabaci-infested tomato plants show phase-specific pattern of photosynthetic gene expression indicative of disrupted electron flow leading to photo-oxidation and plant death

A suppression-subtractive-hybridization (SSH) strategy led to the identification of several genes whose expression was differentially modified in response to different larval phases present during the infestation process of tomato plants (Solanum lycopersicum) by virus-free whitefly Bemisia tabaci (Bt, biotype A). The findings regarding photosynthetic gene expression were in accordance to previous studies reporting altered patterns of expression as a result of insect herbivory. However, the examination, in this study, of four stages of larval Bt development permitted the detection of phase-dependent changes in gene expression which appeared to target specific photosynthetic complexes. Thus, an up-regulation of photosystem II genes in the latter two phases of Bt development contrasted with a general repression of genes belonging to the three other photosynthetic complexes, in addition to a number of genes coding for proteins associated with the oxygen evolving complex and the Calvin cycle. We propose that the contrasting pattern of expression led to an over-excitation of PSII and consequent oxidative damage, as suggested by the concomitant up-regulation of oxidative stress genes, and could have contributed to the wide-spread necrosis observed in Bt-infested tomato plants at late stages of the plant-insect interaction.