Mitochondrial GPX1 silencing triggers differential photosynthesis impairment in response to salinity in rice plants

The physiological role of plant mitochondrial glutathione peroxidases is scarcely known. This study attempted to elucidate the role of a rice mitochondrial isoform(GPX1) in photosynthesis under normal growth and salinity conditions. GPX1 knockdown rice lines(GPX1s) were tested in absence and presence of 100 mM NaCl for 6 d.Growth reduction of GPX1 s line under non-stressful conditions, compared with non-transformed(NT) plants occurred in parallel to increased H_2O_2 and decreased GSH contents. These changes occurred concurrently with photosynthesis impairment, particularly in Calvin cycle's reactions, since photochemical efficiency did not change.Thus, GPX1 silencing and downstream molecular/metabolic changes modulated photosynthesis differentially. In contrast, salinity induced reduction in both phases of photosynthesis, which were more impaired in silenced plants.These changes were associated with root morphology alterations but not shoot growth. Both studied lines displayed increased GPX activity but H_2O_2 content did not change in response to salinity. Transformed plants exhibited lower photorespiration, water use efficiency and root growth, indicating that GPX1 could be important to salt tolerance. Growth reduction of GPX1 s line might be related to photosynthesis impairment, which in turn could have involved a cross talk mechanism between mitochondria and chloroplast originated from redox changes due to GPX1 deficiency.     

Standardized Heat Fixation for Blood Smears

Because a technique was needed for good fixation of blood smears without the use of solvents such as methanol, the effect of heat fixation on human and rat blood smears was studied. Slides were placed in a fused silica dish, covered by a Pyrex petri dish lid, and heated for 5 min in an oven at 150° C. After such fixation, smears stained by Giemsa' s solution showed that the blood elements retained their characteristic morphology. Thus, even though volatile substances may be lost and heat-labile constituents may be modified, this simple method avoids contact of the cells with solvents.     

Production of metabolites with antioxidant activity by Botryosphaeria dothidea in submerged fermentation

Bioprocess and Biosystems Engineering - Antioxidants are able of inhibiting free radicals and play an important role in human diet, protection of foods, anti-aging cosmetics, among others. Fungi...