Development of synbiotic weaning food supplemented with spirulina grown under precise/mild stress conditions

For alleviating child malnutrition, functional food from natural resources such as microalgae predominantly cyanobacteria came into existence as consumers today are more health conscious. No work of technological or scientific significance has been reported on standardized method for development of pearl millet weaning food supplemented with Spirulina maxima. Therefore, feasibility trials were done on the basis of sensory attributes analysis. Spirulina powder grown in optimized laboratory conditions was screened for its phytochemical constituents. The standardized product consisted of one part of pearl millet grounded for 5 min cooked with eight parts of water, 5% salt and 0.8% of cumin powder. Cooked weaning food mixed with 1% curd culture, 1.5% Spirulina powder and incubated for 12 h (fermentation). Standardized product consisting of this formulation scored 8.13, 7.93, 7.88, 7.94, 7.30, 8.14 for colour and appearance, flavour, consistency, mouthfeel, acidity and overall acceptability, respectively on 9 points hedonic scale

Modulation of AsA-GSH cycle by exogenous nitric oxide and hydrogen peroxide to minimize the Cd-induced damages in photosynthetic cyanobacteria

Cyanobacteria, the prominent nitrogen fixers, are facing many stressful situations throughout their life span, hence in recent years the yield and productivity of paddy crops are highly compromised. To address this problem, this study is structured to investigate how signaling molecules can positively influence the ability of tested cyanobacteria to counteract the adverse effects of metal stress. Thus, the main objective of this study is to elucidate the importance and crosstalk of intracellular signaling molecules, nitric oxide (NO), and hydrogen peroxide (H2O2) during Cd stress tolerance in cyanobacteria. The effect of exogenous gasotransmitter, NO and redox molecule, H2O2, in mitigation of cadmium (Cd, 6 µM) toxicity on different physiological and biochemical activities were well recorded in economically important cyanobacteria Nostoc muscorum ATCC 27893 and Anabaena sp. PCC 7120. Under Cd stress increased Cd accumulation and oxidative stress in test cyanobacteria, impaired the functioning of the ascorbate-glutathione (AsA-GSH) cycle. Exogenous application of NO (10 µM) and H2O2 (1 µM) ameliorated the negative effects of Cd through boosting-up the activities of enzymatic (ascorbate peroxidase, glutathione reductase and dehydroascorbate reductase) and the contents of non-enzymatic (cysteine, proline, ascorbate, glutathione and non-protein-thiols) antioxidants. The application of NO scavenger (PTIO) or NO synthase enzyme inhibitor (LNAME) to the Cd-stressed cells abolished the recovery of the above parameters, even in the presence of exogenous H2O2. Notwithstanding to this, under similar stress exogenous addition of scavenger of H2O2 (NAC) or inhibitor of NADPH oxidase enzyme (DPI) to the growth medium could not restrict the recovery of the above parameters in the presence of NO, hence pointing towards the major role of NO in tolerance of the test organisms to Cd stress. In conclusion, the finding revealed that NO plays a vital role in H2O2 signaling to attain Cd stress tolerance in cyanobacteria. Moreover, the study has created a scope to search for deeper insight into signaling interactions between other gasotransmitters and redox molecules in cyanobacteria. Further, the current finding recommends using a lower dose of SNP (NO donor, a cost-effective chemical) in paddy fields may ensure better growth of cyanobacteria (biofertilizer) even under prevailing stress conditions for sustainable agriculture to maintain productivity of rice crops

Hydrogen sulfide regulates NaCl tolerance in brinjal and tomato seedlings by Na+/K+ homeostasis and nitrogen metabolism

In the present study, hydroponic experiments were performed to explore the mechanistic role of H2S (NaHS (donor of H2S); 40 μM) in alleviating NaCl stress in brinjal and tomato seedlings by analyzing the growth, pigments content, gas exchange parameters, and contents of inorganic nitrogen and activities of enzymes involved in N2 metabolism. While NaCl at 20 mM declined the growth (tolerance index (TI) and plant height), pigment content (total chlorophyll and Chl a/b), and gas exchange parameters (intercellular CO2 concentration; Ci, net photosynthetic rate; A, transpiration rate; E, stomatal conductance; Gs). It also variably affected the inorganic N (NO3−, NO2− and NH4+) content, and the enzymes involved in nitrate (nitrate reductase; NR and nitrite reductase; NiR), and ammonium (glutamine synthetase; GS, glutamate synthase; GOGAT and Glutamate dehydrogenase; GDH) assimilation, whereas the supplementation of H2S showed considerable improvement in all the studied parameters. Furthermore, the addition of H2S scavenger hypotaurine (HT; 200 μM) to NaCl + NaHS seized all the recovery on the above parameters caused by the NaHS treatment, suggesting the role of exogenous H2S. While, the addition of an inhibitor of H2S generation propargylglycine (PAG; 100 μM) to NaCl treatments further declined the growth more than NaCl treatment alone, implying the role of endogenous H2S. Altogether, our study highlights the modulatory role of endogenous and exogenous H2S in conferring NaCl stress tolerance in brinjal and tomato seedlings by maintaining the ion homeostasis and the C/N ratio

Heavy metal tolerance in plants: Role of transcriptomics, proteomics, metabolomics and ionomics

Heavy metal contamination of soil and water causing toxicity/stress has become one important constraint to crop productivity and quality. This situation has further worsened by the increasing population growth and inherent food demand. It have been reported in several studies that counterbalancing toxicity, due to heavy metal requires complex mechanisms at molecular, biochemical, physiological, cellular, tissue and whole plant level, which might manifest in terms of improved crop productivity. Recent advances in various disciplines of biological sciences such as metabolomics, transcriptomics, proteomics etc. have assisted in the characterization of metabolites, transcription factors, stress-inducible proteins involved in heavy metal tolerance, which in turn can be utilized for generating heavy metal tolerant crops. This review summarizes various tolerance strategies of plants under heavy metal toxicity, covering the role of metabolites (metabolomics), trace elements (ionomics), transcription factors (transcriptomics), various stress-inducible proteins (proteomics) as well as the role of plant hormones. We also provide a glance at strategies adopted by metal accumulating plants also known as metallophytes

Validation of a questionnaire to identify noise-induced hearing loss among drivers

Objective: To assess the validity of a questionnaire (consisting of 10 items/questions) to identify hearing loss (HL) among three-wheeler tempo and noncommercial car drivers. Materials and Methods: This was a cross-sectional study conducted in an urban area of Lucknow city. Three-wheeler tempo drivers and noncommercial car drivers were assessed for HL by audiometry. A total of 300 subjects, who fulfilled the study criteria, were selected for the interview and health assessment. The pure tone audiometry was conducted after >12 hours of the last noise exposure to avoid temporary threshold shift. Results: The percentage of respondents aged between 31 and 40 years was 36%. The highest affirmative response item was “Do you have trouble hearing in noisy background?” constituting 68% and the lowest affirmative response item was “Do you have trouble understanding the speech of women and children?” constituting 33.7%. Kappa values showed that there was significantly (<0.05) mild agreement between most of the items and the gold standard for mid and high-frequency HL. The area under the curve for low, mid, and high frequency HL was 0.76% (95% CI = 0.68–0.84), 0.69 (95% CI = 0.73–0.75), and 0.67 (95% CI = 0.62–0.73), respectively. The sensitivity and specificity were reasonable for all the definition of HL at different cutoff scores. Conclusion: A self-reported questionnaire-based approach may be used for the assessment of HL especially when audiometry is not feasible

Reactive oxygen species signaling and stomatal movement: Current updates and future perspectives

Reactive oxygen species (ROS), a by-product of aerobic metabolism were initially studied in context to their damaging effect but recent decades witnessed significant advancements in understanding the role of ROS as signaling molecules. Contrary to earlier views, it is becoming evident that ROS production is not necessarily a symptom of cellular dysfunction but it might represent a necessary signal in adjusting the cellular machinery according to the altered conditions. Stomatal movement is controlled by multifaceted signaling network in response to endogenous and environmental signals. Furthermore, the stomatal aperture is regulated by a coordinated action of signaling proteins, ROS-generating enzymes, and downstream executors like transporters, ion pumps, plasma membrane channels, which control the turgor pressure of the guard cell. The earliest hallmarks of stomatal closure are ROS accumulation in the apoplast and chloroplasts and thereafter, there is a successive increase in cytoplasmic Ca2+ level which rules the multiple kinases activity that in turn regulates the activity of ROS-generating enzymes and various ion channels. In addition, ROS also regulate the action of multiple proteins directly by oxidative post translational modifications to adjust guard cell signaling. Notwithstanding, an active progress has been made with ROS signaling mechanism but the regulatory action for ROS signaling processes in stomatal movement is still fragmentary. Therefore, keeping in view the above facts, in this mini review the basic concepts and role of ROS signaling in the stomatal movement have been presented comprehensively along with recent highlights. Keywords: Calcium, Guard Cell, Reactive oxygen species, Stomatal movement, Transcription factor

Regulation of ascorbate-glutathione cycle by exogenous nitric oxide and hydrogen peroxide in soybean roots under arsenate stress

The role of nitric oxide (NO) and hydrogen peroxide (H2O2) is well known for regulating plant abiotic stress responses. However, underlying mechanisms are still poorly understood. Therefore, the present study investigated the involvement of NO and H2O2 signalling in the regulation of arsenate toxicity (AsV) in soybean roots employing a pharmacological approach. Results show that AsV toxicity declined root length and biomass due to greater As accumulation in the cell wall and cellular organelles. Arsenate induced cell death due to enhanced levels of reactive oxygen species, lipid and protein oxidation and down-regulation in ascorbate-glutathione cycle and redox states of ascorbate and glutathione. These results correlate with lower endogenous level of NO. Interestingly, addition of L-NAME increased AsV toxicity. However, addition of SNP reverses effect of L-NAME, suggesting that endogenous NO has a role in mitigating AsV toxicity. Exogenous H2O2 also demonstrated capability of alleviating AsV stress, while NAC reversed the protective effect of H2O2. Furthermore, DPI application further increased AsV toxicity, suggesting that endogenous H2O2 is also implicated in mitigating AsV stress. SNP was not able to mitigate AsV toxicity in the presence of DPI, suggesting that H2O2 might have acted downstream of NO in accomplishing amelioration of AsV toxicity