Plant growth promoting rhizobacteria alleviate salinity induced negative effects on growth, oil content and physiological status in Mentha arvensis

This study was aimed to investigate the effect of inoculation on three salt-tolerant, plant-growth-promoting rhizobacteria (PGPR) STR2 (Bacillus pumilus), STR8 (Halomonas desiderata) and STR36 (Exiguobacterium oxidotolerans), for their growth-promoting potential and efficacy in augmenting salt tolerance in Mentha arvensis, an essential oil-bearing crop and natural source of l-menthol, under varying levels of NaCl stress (0, 100, 300 and 500 mM) imposed through irrigating water. Increase in the levels of salt concentration led to a decrease in the growth, fresh weight, leaf–stem ratio, oil content and yield. However, the negative effects of salinity were observed to be convalesced in the PGPR inoculated plants. At salinity levels of 100 and 300 mM NaCl, H. desiderata inoculated plants recorded the highest herb yield, whereas at 500 mM NaCl, the plants inoculated with E. oxidotolerans yielded maximum herb. The oil content in non-inoculated, salt-stressed plants was observed to be 0.46, 0.42 and 0.35 % at 100, 300 and 500 mM NaCl, respectively, whereas the plants inoculated with H. desiderata recorded the oil content of 0.71 and 0.60 and 0.48 % at similar levels of NaCl stress, respectively. The halotolerant PGPR minimized the deleterious effects of salt toxicity producing at par or higher yields at lower and medium salinity levels (100, 300 mM NaCl) than the un-inoculated non-salt-stressed plants through improved foliar nutrient uptake and enhanced antioxidant machinery. Based on the results of the experiments reported herein, the use of salt-tolerant, plant-growth-promoting bacteria may provide an effective means of facilitating M. arvensis growth in salt-stressed environments.     

Evaluating genomic DNA extraction methods from human whole blood using endpoint and real-time PCR assays

The extraction of genomic DNA is the crucial first step in large-scale epidemiological studies. Though there are many popular DNA isolation methods from human whole blood, only a few reports have compared their efficiencies using both end-point and real-time PCR assays. Genomic DNA was extracted from coronary artery disease patients using solution-based conventional protocols such as the phenol–chloroform/proteinase-K method and a non-phenolic non-enzymatic Rapid-Method, which were evaluated and compared vis-a-vis a commercially available silica column-based Blood DNA isolation kit. The appropriate method for efficiently extracting relatively pure DNA was assessed based on the total DNA yield, concentration, purity ratios (A₂₆₀/A₂₈₀ and A₂₆₀/A₂₃₀), spectral profile and agarose gel electrophoresis analysis. The quality of the isolated DNA was further analysed for PCR inhibition using a murine specific ATP1A3 qPCR assay and mtDNA/Y-chromosome ratio determination assay. The suitability of the extracted DNA for downstream applications such as end-point SNP genotyping, was tested using PCR-RFLP analysis of the AGTR1-1166A>C variant, a mirSNP having pharmacogenetic relevance in cardiovascular diseases. Compared to the traditional phenol–chloroform/proteinase-K method, our results indicated the Rapid-Method to be a more suitable protocol for genomic DNA extraction from human whole blood in terms of DNA quantity, quality, safety, processing time and cost. The Rapid-Method, which is based on a simple salting-out procedure, is not only safe and cost-effective, but also has the added advantage of being scaled up to process variable sample volumes, thus enabling it to be applied in large-scale epidemiological studies.     

Quercetin plays protective role in oxidative induced apoptotic events during chronic chlorpyrifos exposure to rats

Chlorpyrifos (CPF), an organophosphate insecticide has a wider application throughout the world to protect agricultural crops and vegetables from insects. Polyphenolic compounds are considered as beneficial against toxicities induced by organophosphates. The present study was conducted to understand the neuroprotective role of quercetin in chlorpyrifos‐induced apoptotic events in rats. Twenty‐four male Sprague Dawley rats weighing 170 to 200 g were divided into four groups viz: Control, chlorpyrifos treated (13.5 mg/kg body wt. alternate day), quercetin treated (50 mg/kg body wt. every day) and combined chlorpyrifos + quercetin treated. All the treatments were carried out for a total duration of 60 days. Protein carbonyl content and acetylcholinesterase activity were estimated in serum along with cerebrum and cerebellum to ascertain neurotoxicity. Further, for appraisal of neurodegeneration as a consequence of apoptosis, protein expressions of Bcl‐2, Bax, cytochrome c, caspase‐8, and caspase‐9 were assessed. The results showed that protein carbonyl contents were markedly increased in both serum and brain tissues (cerebrum and cerebellum) of chlorpyrifos‐treated rats when compared with control group and were appreciably improved upon simultaneous supplementation with quercetin. Further, chlorpyrifos treatment revealed a significant decrease in the enzyme activity of acetylcholinesterase in serum as well as in cerebrum and cerebellum, which however was increased upon concomitant treatment with quercetin. In chlorpyrifos‐treated animals, we have observed a significant decrease in the protein expression level of Bcl‐2, but a remarkable increase in the expression levels of Bax, cytochrome c, caspase‐8, and caspase‐9 in both cerebrum and cerebellum. Interestingly, when chlorpyrifos‐treated animals were supplemented with quercetin, a significant increase in the expression of Bcl‐2 and an appreciable decline in the expression levels of Bax, cytochrome c, caspase‐8, and caspase‐9 was observed. In conclusion, the present study advocates that quercetin may prove to be a useful candidate in containing the oxidative‐induced apoptotic events during chlorpyrifos exposure.     

Protective effects of sodium orthovanadate in diabetic reticulocytes and ageing red blood cells of Wistar rats

The reticulocytes and the ageing red blood cells (RBCs) namely young (Y), middle-aged (M) and old RBCs (O) of female Wistar rats from different groups such as control animals (C), controls treated with vanadate (C + V), alloxan-induced diabetic (D), diabetic-treated with insulin (D + I) and vanadate (D + V), were fractionated on a percoll/BSA gradient. The following enzymes were measured-hexokinase (HK), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), glutathione-s-transferase (GST), alanine aminotransferase ΜlaAT), aspartate aminotransferase ΜsAT) and arginase in the hemolysates of all the RBCs fractions. Decreases in the activity of HK and AsAT by about 70%, arginase and GSH-Px by 30% in old RBCs were observed in comparison to reticulocytes of control animals. Increases in the activity of GSSG-R by 86%, AlaAT by more than 400% and GST by 70% were observed in old RBCs in comparison to reticulocytes of control animals. Alloxan diabetic animals showed a further decrease in the activities of HK in Y RBCs by 37%, M RBCs by 39% and O RBCs by 32%, GSH-Px activity in Y RBCs by 13%, M RBCs by 20% and O RBCs by 33% and GST activity in Y RBCs by 14%, M RBCs by 42% and O RBCs by 60% in comparison to their corresponding cells of control animals. An increase in the activity of all the enzymes studied was also observed in reticulocytes of diabetic animals in comparison to reticulocytes of controls. The GSSG-R activity was found to be increased in Y RBCs by 49%, M RBCs by 67% and O RBCs by 64% as compared to the corresponding age-matched cells of control animals. The activity of arginase also decreased in Y RBCs by about10%, M RBCs by 20% and O RBCs by 30% in comparison to the age-matched cells of control animals. A decrease in the activity of AsAT in Y and M RBCs by 30%, and O RBCs by 25% was observed in diabetic animals in comparison to the agematched cells of control animals. The activity of AlaAT was found to be decreased by more than 10% in Y and M RBCs and 25% in O RBCs of diabetic animals in comparison to the age-matched cells of control animals. Insulin administration to diabetic animals reversed the altered enzyme activity to control values. Vanadate treatment also reversed the enzyme levels except for that of GST in old cells     

Regulation of cellulase production in two thermophilic fungi Melanocarpus sp. MTCC 3922 and Scytalidium thermophilum MTCC 4520

This paper reports regulation of cellulase production in two thermophilic fungi, Melanocarpus sp. MTCC 3922 and Scytalidium thermophilum MTCC 4520. The expression of endoglucanase (EG), avicel adsorbable endoglucanase (AAEG) and β-glucosidase in both fungi was inducible. Of the different carbon sources tested, rice straw induced maximal levels of cellulase in both fungi. While, the addition of fructose (1%, w/v) to the carboxymethylcellulose (CMC) medium resulted in two-fold increase in endoglucanase production in Melanocarpus sp., however, the addition of ethanol (1%, v/v) resulted in eight-fold-increased expression of endoglucanase in S. thermophilum. The expression profiles of different components of cellulase complex were shown to be co-regulated in S. thermophilum but independently regulated in Melanocarpus sp.