Green synthesis, characterization and antimicrobial activity of silver nanoparticles using methanolic root extracts of Diospyros sylvatica

The current research study focuses to formulate the biosynthesized silver nanoparticles for the first time from silver acetate using methanolic root extracts of Diospyros sylvatica, a member of family Ebenaceae. TEM analysis revealed the average diameter of Ag NPs around 8 nm which is in good agreement with the average crystallite size (10 nm) calculated from X-ray Diffraction (XRD) analysis. Further the study has been extended to the antimicrobial activity against test pathogenic Gram (+) ve, Gram (−) ve bacterial and fungal strains. The bioinspired Ag-NP showed promising activity against all the tested bacterial strains and the activity was enhanced with increased dosage levels.     

Arsenic toxicity in garden cress (Lepidium sativum Linn.): significance of potassium nutrition

In a hydroponic culture, experiments were performed to study the influence of potassium (K) supplementation (0, 20, 40, 60, 80, and 100 mg L^?1) on the arsenic (As; 0, 8, and 10 mg L^?1)-accrued changes in growth traits (plant biomass, root–shoot length) and the contents of lepidine, As and K, in garden cress (Lepidium sativum Linn.) at 10 days after treatment. The changes in these traits were correlated with shoot proline content, protein profile, and the activities of antioxidant enzymes namely superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), glutathione reductase (GR, EC 1.8.1.7), and ascorbate peroxidase (APX, EC 1.11.1.11). In general, As-alone treatments significantly decreased the growth traits but lead to significant enhancements in shoot proline and enzyme activities. K-supplementation to As-treated L. sativum seedlings decreased shoot-As content, reduced As-induced decreases in growth traits but enhanced the content of shoot proline, and the activities of the studied enzymes maximally with K₁₀₀ + As₈ and As₁₀ mg L^?1. Both 8 and 10 mg L^?1 of As drastically downregulated the shoot proteins ranging from 43–65 kDa. With As₁₀ mg L^?1, there was a total depletion of protein bands below 23 kDa; however, K₈₀ mg L^?1 maximally recovered and upregulated the protein bands. Additionally, protein bands were downregulated (at par with As-alone treatment) above K₈₀ mg L^?1 level. Interestingly, As-stress increased lepidine content in a dose-dependent manner which was further augmented with the K-supplementation. It is suggested that K protects L. sativum against As-toxicity by decreasing its accumulation and strengthening antioxidant defense system and protein stability.     

Risk factors and prevalence of dental fluorosis and dental caries in school children of North India

The aim of the study was to assess the prevalence of dental fluorosis, dental caries, and associated risk factors in the school children of district Fatehgarh Sahib, Punjab, India, using a cross-sectional study design. Oral health status of children aged between 8 and 15 years was assessed using World Health Organization (WHO) 2013 criteria. Dental fluorosis was assessed using Dean’s index, and dental caries were recorded using decayed, missing, filled/decayed, extracted, filled (DMF/def) indices. Four hundred school children were examined, of which 207 were in the 8–11-year-old group and 193 were in the 12–15-year-old group. The overall prevalence of dental fluorosis was 4.1%, which might be linked to a high concentration of fluoride in drinking water at certain locations of rural Punjab. The prevalence of dental caries was 36.5% with a mean DMF score of 0.3 and def score of 0.6. Risk factors for dental caries include oral hygiene behavior and sugar consumption patterns. The study highlights the need to increase awareness about the oral health and hygiene among the school children in India.     

Leaf biochemistry of Lycopersicon esculentum Mill. at different stages of plant development as affected by mercury treatment

The effect of mercury (Hg) on the biochemical parameters of Lycopersicon esculentum Mill leaf was studied. Application of mercuric chloride in varying concentrations (0.5, 1.0, 1.5 and 2.0 mM HgCl2 kg(-1) sand) caused significant reduction that went up to 89% and 72% chlorophyll a and chlorophyll b contents respectively (at flowering stage), 69% in carotenoid content, 64% in total soluble protein content and 91% in nitrate reductase activity (all at post-flowering stage). The amounts of nitrate and proline increased maximally (151% and 143% respectively) at the flowering stage, whereas total soluble sugar enhanced by 57% at the post-flowering stage. Changes observed in most of the parameters, were concentration dependent. Such studies seem to be able to discover suitable bioindicators of heavy metal pollution.     

Neurotoxic and genotoxic effects of methylmercury

The toxic form of methylmercury is of concern in terms of its neurotoxicity, genotoxicity and reproductive toxicity. Extensive research has been carried out on the effects of exposure to high levels of this toxic compound, but this is not true for research on exposure to lower levels. The harmful effects of methylmercury are a cause for concern irrespective of the exposure levels. The problem becomes more serious because of biomagnifications of methylmercury. Disorders may develop during neonatal stage and then develop further during the lifetime. The common effects which can be seen are retarded brain development and permanent disorders like cerebral palsy. This can also cause neurogenerative disorders like Alzheimer’s and Parkinson’s. Research on animals has also shown toxicity. Inorganic Hg was found to be present in brains of neonatal rats, in monkeys prenatal exposure to MeHg resulted in a reduced number of births, and birds laid a lesser number of eggs and the infant mortality rate was higher.