Chromium tolerance,oxidative stress response,morphological characteristics,and FTIR studies of phytopathogenic fungus <Emphasis Type="Italic">Sclerotium rolfsii</Emphasis>

Sclerotium rolfsii is one of the most destructive fungal plant pathogens that can infect over 500 plants and can adapt to diverse environmental conditions. The present research work was carried out to evaluate the impact of both hexa- and trivalent chromium (Cr) on growth, morphology, enzymatic characteristics, and metal accumulation in S. rolfsii under laboratory conditions. Experiments were performed in both malt extract broth and agar growth medium amended with six different concentrations (10, 20, 40, 60, 80, and 100 ppm) of each Cr(III) and Cr(VI) ions inoculated with fungus and incubated for 6–7 days at 25 ± 3 °C. In broth medium, the total protein content was declined and activities of antioxidant enzymes were increased with an increase in metal concentrations. Lower concentrations (10 ppm) of the metal ions stimulated the growth of fungus and higher concentrations (60–100) inhibited it. The Fourier transform infrared spectroscopy (FTIR) assessment showed hydroxyl, carboxyl, and amine groups as major metal binding sites. In agar medium, tolerance index was decreased up to 0.56 at 10–80 ppm of Cr(III) and up to 0.62 at 10–60 ppm of Cr(VI). Considerable modifications were observed in hyphal and sclerotial morphology with an increase in concentration of metal ions. The current study concluded that interference of Cr with growth and physiological process of S. rolfsii could affect its infection level on its host plant. This study provides important information regarding cultivation of susceptible plant varieties in Cr-polluted soil as evidenced by pathogen growth up to 50 ppm of Cr(III) and Cr(VI) ions.     

Study of interaction effect between triacontanol and nitric oxide on alleviating of oxidative stress arsenic toxicity in coriander seedlings

In this study, triacontanol (TRIA) and nitric oxide (NO) interaction on arsenic (As)-induced oxidative stress tolerance in coriander (Coriandrum sativum L.) plants was investigated. The results showed that As had a significant adverse effect on the plant’s biomass. The seedlings pretreated with TRIA and NO significantly increased growth reduction induced by the metalloid. The obtained results indicated that the application of TRIA and sodium nitroprusside (SNP) generally reduced oxidative markers such as of electrolyte leakage percentage, malondialdehyde and H₂O₂ contents under As toxicity, while application of As treatment without TRIA?+?SNP increased these oxidative parameters compared to the control. The non-enzymatic antioxidant contents such as total phenol, anthocyanin, carotenoid, ascorbic acid and reduced glutathione (GSH) were extracted and assayed from both control and treated plants. It was found that TRIA?+?SNP treatments have a profound effect on the antioxidant metabolism and caused an enhancement in non-enzymatic antioxidant potentials under As toxicity in coriander. Moreover, the results revealed a mutually amplifying reaction between TRIA and NO in reducing As-induced damages.     

Antimicrobial activities of Gloriosa superba Linn (Colchicaceae) extracts

The methanol extract of the rhizomes of Gloriosa superba Linn (Colchicaceae) and its subsequent fractions in different solvent systems were screened for antibacterial and antifungal activities. Excellent antifungal sensitivity was expressed by the n-butanol fraction against Candida albicans and Candida glaberata (up to 90%) and against Trichophyton longifusus (78%) followed by the chloroform fraction against Microsporum canis (80%). In the antibacterial bioassay, the crude extract and subsequent fractions showed mild to moderate antibacterial activities. Chloroform fraction displayed highest antibacterial sensitivity against Staphylococcus aureous (88%) followed by the crude extract (59%). The total phenol content of the crude extract and fractions of the plant expressed no significant correlation with the antimicrobial activities.     

Validation of a simplified method for determination of cimetidine in human plasma and urine by liquid chromatography with ultraviolet detection

A HPLC method was developed for determination of cimetidine in human plasma and urine. Plasma samples were alkalinized followed by liquid extraction with water-saturated ethyl acetate then evaporated under nitrogen. The extracts were reconstituted in mobile phase and injected onto a C(18) reversed-phase column; UV detection was set at 228 nm. Urine samples were diluted with an internal standard/mobile phase mixture (1:9) prior to injection. The lower limit of quantification in plasma and urine were 100 ng/ml and 10 microg/ml, respectively; intra- and inter-day coefficients of variation were 相似文献   

Genetic Association of Butyrylcholinesterase with Major Depressive Disorder

Biochemical Genetics - Major depressive disorder (MDD) is characterized as clinical depression, which primarily affects the mood and behaviour of an individual. In the present study...     

Structural basis for interaction between the Ubp3 deubiquitinating enzyme and its Bre5 cofactor

The Bre5 protein is a cofactor for the deubiquitinating enzyme Ubp3, and it contains a nuclear transfer factor 2 (NTF2)-like protein recognition module that is essential for Ubp3 activity. In this study, we report the x-ray crystal structure of the Bre5 NTF2-like domain and show that it forms a homodimeric structure that is similar to other NTF2-like domains, except for the presence of an intermolecular disulfide bond in the crystals. Sedimentation equilibrium studies reveal that under non-reducing conditions, the Bre5 NTF2-like domain is exclusively dimeric, whereas a disulfide bond-deficient mutant undergoes a monomer-dimer equilibrium with a dissociation constant in the midnanomolar range, suggesting that dimer formation and possibly also disulfide bond formation may modulate Bre5 function in vivo. Using deletion analysis, we also identify a novel N-terminal domain of Ubp3 that is necessary and sufficient for interaction with Bre5 and use isothermal titration calorimetry to show that Bre5 and Ubp3 form a 2:1 complex, in contrast to other reported NTF2-like domain/protein interactions that form 1:1 complexes. Finally, we employ structure-based mutagenesis to map the Ubp3 binding surface of Bre5 to a region near the Bre5 dimer interface and show that this binding surface of Bre5 is important for Ubp3 function in vivo. Together, these studies provide novel insights into protein recognition by NTF2-like domains and provide a molecular scaffold for understanding how Ubp3 function is regulated by Bre5 cofactor binding.     

DNA repair in higher plants; photoreactivation is the major DNA repair pathway in non-proliferating cells while excision repair (nucleotide excision repair and base excision repair) is active in proliferating cells

We investigated expression patterns of DNA repair genes such as the CPD photolyase, UV-DDB1, CSB, PCNA, RPA32 and FEN-1 genes by northern hybridization analysis and in situ hybridization using a higher plant, rice (Oryza sativa L. cv. Nipponbare). We found that all the genes tested were expressed in tissues rich in proliferating cells, but only CPD photolyase was expressed in non-proliferating tissue such as the mature leaves and elongation zone of root. The removal of DNA damage, cyclobutane pyrimidine dimers and (6–4) photoproducts, in both mature leaves and the root apical meristem (RAM) was observed after UV irradiation under light. In the dark, DNA damage in mature leaves was not repaired efficiently, but that in the RAM was removed rapidly. Using a rice 22K custom oligo DNA microarray, we compared global gene expression patterns in the shoot apical meristem (SAM) and mature leaves. Most of the excision repair genes were more strongly expressed in SAM. These results suggested that photoreactivation is the major DNA repair pathway for the major UV-induced damage in non-proliferating cells, while both photoreactivation and excision repair are active in proliferating cells.     

Role of pollination in yield and physicochemical properties of tomatoes (Lycopersicon esculentum)

Very little is known about pollination and its effects on the yield and physicochemical properties of flowering plants in tropical countries. Wind and insect pollinators are among our natural resources because pollination is the most important ecosystem service performed by wind and insects, and is vital to the socio-economic status of human beings. In this experiment, different pollination methods for tomato plants were examined. Self-pollination was encouraged by covering the plants with a plastic sheet. Wind and insects were excluded from these plants, and thus only self-pollination was possible. The experiment occurred during the flowering stage. Wind-pollinated plants were covered with a muslin cloth, which excluded insects, and only wind could pass through the cloth. For insect pollination, plants remained uncovered, allowing free access to insects to pollinate the flowers. At fruit maturity, when fruits were completely red, fruits from each treatment were harvested on the same date and under the same conditions. Results illustrated the substantial importance of insects as pollinators of tomato crops. Open field had greater tomato yield and positive effects on physicochemical properties on fruit than under self and wind pollination.     

Terminal drought and seed priming improves drought tolerance in wheat

Plants retain the preceding abiotic stress memory that may aid in attainment of tolerance to subsequent stresses. This study was conducted to evaluate the influence of terminal drought memory (drought priming) and seed priming in improving drought tolerance in wheat (Triticum aestivum L.). During first growing season, wheat was planted in field under optimal (well-watered) and drought stress imposed at reproductive stage (BBCH growth stage 49) until maturity (BBCH growth stage 83). Seeds collected from both sources were subjected to hydropriming or osmopriming (with 1.5% CaCl₂ solution); while, dry seed was taken as control. Treated and control seeds, from both sources, were sown in soil filled pots. After the completion of seedling emergence, pots were maintained at 50% water holding capacity (drought) or 100% water holding capacity (well-watered). Drought stress suppressed the plant growth (2–44%), perturbed water relations (1–18%) and reduced yield (192%); however, osmolytes accumulation (3–14%) and malondialdehyde contents (26–29%) were increased under drought. The crop raised from the seeds collected from terminal drought stressed plants had better growth (5–63%), improved osmolyte accumulation (13–45%), and lower lipid peroxidation (3%) than the progeny of well-watered crop. Seed priming significantly improved the crop performance under drought stress as compared to control. However, osmopriming was more effective than hydropriming in this regard as it improved leaf area (9–43%), tissue water status (2–47%), osmolytes accumulation (6–48%) and grain yield (14–79%). In conclusion, terminal drought induced modifications in seed composition and seed priming improved transgenerational drought tolerance through improvement in tissue water status and osmolytes accumulation, and decrease in lipid peroxidation.