Phytoremediation technologies and their mechanism for removal of heavy metal from contaminated soil: An approach for a sustainable environment.

The contamination of soils with heavy metals and its associated hazardous effects are a thrust area of today's research. Rapid industrialization, emissions from automobiles, agricultural inputs, improper disposal of waste, etc., are the major causes of soil contamination with heavy metals. These contaminants not only contaminate soil but also groundwater, reducing agricultural land and hence food quality. These contaminants enter the food chain and have a severe effect on human health. It is important to remove these contaminants from the soil. Various economic and ecological strategies are required to restore the soils contaminated with heavy metals. Phytoremediation is an emerging technology that is non-invasive, cost-effective, and aesthetically pleasing. Many metal-binding proteins (MBPs) of the plants are significantly involved in the phytoremediation of heavy metals; the MBPs include metallothioneins; phytochelatins; metalloenzymes; metal-activated enzymes; and many metal storage proteins, carrier proteins, and channel proteins. Plants are genetically modified to enhance their phytoremediation capacity. In Arabidopsis, the expression of the mercuric ion-binding protein in Bacillus megaterium improves the metal accumulation capacity. The phytoremediation efficiency of plants is also enhanced when assisted with microorganisms, biochar, and/or chemicals. Removing heavy metals from agricultural land without challenging food security is almost impossible. As a result, crop selections with the ability to sequester heavy metals and provide food security are in high demand. This paper summarizes the role of plant proteins and plant-microbe interaction in remediating soils contaminated with heavy metals. Biotechnological approaches or genetic engineering can also be used to tackle the problem of heavy metal contamination.

Barley Melanoidins: Key Dietary Compounds With Potential Health Benefits.

This paper is a review of the potential health benefits of barley melanoidins. Food melanoidins are still rather understudied, despite their potential antioxidant, antimicrobial, and prebiotic properties. Free radicals are villainous substances in humans produced as metabolic byproducts and causing cancers and cardiovascular diseases, and the melanoidins alleviate the effects of these free radicals. Malt is produced from cereal grains such as barley, wheat, and maize, and barley is predominantly used in beer production. Beer (alcoholic and non-alcoholic) is a widely consumed beverage worldwide and a good source of dietary melanoidins, which enhance the beers' flavor, texture, and sensorial properties. Melanoidins, the final products of the Maillard reaction, are produced at different stages during the brewing process. Beer melanoidins protect the cells from oxidative damage of DNA. The high reducing capacity of melanoidins can induce hydroxyl radicals from H2O2 in the presence of ferric ion (Fe3+). Melanoidins inhibit lipid peroxidation during digestion due to their chelating metal property. However, lower digestibility of melanoidins leads to less availability to the organisms but is considered to function as dietary fiber that can be metabolized by the lower gut microbiota and possibly incur prebiotic properties. Melanoidins promote the growth of Lactobacilli and Bifidobacteria in the gastrointestinal tract, preventing the colonization of potential pathogens. Barley is already popular through beer production and increasingly as a functional food. Considering this economic and industrial importance, more research to explore the chemical properties of barley melanoidins and corresponding health benefits as barley is warranted.

Impact assessment of major abiotic stresses on the proteome profiling of some important crop plants: a current update.

Abiotic stresses adversely affect the plant's growth and development leading to loss of crop plants and plant products in terms of both the quality and quantity. Two main strategies are adopted by plants to acclimatize to stresses; avoidance and tolerance. These adaptive strategies of plants at the cellular and metabolic level enable them to withstand such detrimental conditions. Acclimatization is associated with intensive changes in the proteome of plants and these changes are directly involved in plants response to stress. Proteome studies can be used to screen for these proteins and their involvement in plants response to various abiotic stresses evaluated. In this review, proteomic studies of different plants species under different abiotic stresses, particularly drought, salinity, heat, cold, and waterlogging, are discussed. From different proteomic studies, the stress response can be determined by an interaction between proteomic and physiological changes which occur in plants during such stress conditions. These identified proteins from different processes under different abiotic stress conditions definitely add to our understanding for exploiting them in various biotechnological applications in crop improvement.

Azadirachta indica plant-assisted green synthesis of Mn3O4 nanoparticles: Excellent thermal catalytic performance and chemical sensing behavior.

The leaf extract of Azadirachta indica (Neem) plant was utilized as reducing agent for the green synthesis of Mn3O4 nanoparticles (NPs). The crystalline analysis demonstrated the typical tetragonal hausmannite crystal structure of Mn3O4, which confirmed the formation of Mn3O4 NPs without the existence of other oxides. Green synthesized Mn3O4 NPs were applied for the catalytic thermal decomposition of ammonium perchlorate (AP) and as working electrode for fabricating the chemical sensor. The excellent catalytic effect for the thermal decomposition of AP was observed by decreasing the decomposition temperature by 175 °C with single decomposing step. The fabricated chemical sensor based on green synthesized Mn3O4 NPs displayed high, reliable and reproducible sensitivity of ∼569.2 µA mM(-1) cm(-2) with reasonable limit of detection (LOD) of ∼22.1 µM and the response time of ∼10 s toward the detection of 2-butanone chemical. A relatively good linearity in the ranging from ∼20 to 160 µM was detected for Mn3O4 NPs electrode based 2-butanone chemical sensor.

Synthesis and evaluation of substituted diphenyl-1,3,4-oxadiazole derivatives for central nervous system depressant activity.

BACKGROUND: Substituted 1,3,4-oxadiazoles are of considerable pharmaceutical interest. 2,5-Substituted diphenyl-1,3,4-oxadiazoles are associated with diverse biological activities by the virtue of -N = C-O- grouping. In the view of wide range of biological properties associated with 1,3,4-oxadiazole, we have synthesized substituted derivatives of 1,3,4-oxadiazole (XIII-XXII), a versatile hydrophobic molecule possessing preliminary CNS properties, with the hope to potentiate the biological activities with lesser or limited amount of toxicities. METHOD: The synthesis was based on ester substitution of substituted benzohydrazide in presence of hydrazine hydrate followed by cyclization in presence of phosphorus oxychloride. All the synthesized compounds were evaluated for their potential CNS depressant activities. Statistical analysis of the anticonvulsant, antidepressant, and antianxiety activity of the synthesized compounds on animals was evaluated using one-way analysis of variance (ANOVA). RESULTS: Two compounds 5-(4-nitrophenyl)-2-(4-chlorophenyl)-1,3,4-oxadiazole (XIV) and 5-(4-nitrophenyl)-2-(4-nitrophenyl)-1,3,4-oxadiazole (XV) were found to be the most promising compounds of the series in antidepressant, anticonvulsant and antianxiety activity with no neurotoxicity when compared with standard. CONCLUSIONS: Among the synthesized compounds, it was found that incorporation of electron withdrawing group at C2 and C5 position of the oxadiazole ring led to high degree of pharmacological activity. Thus compounds 5-(4-nitrophenyl)-2-(4-chlorophenyl)-1,3,4-oxadiazole (XIV) and 5-(4-nitrophenyl)-2-(4-nitrophenyl)-1,3,4-oxadiazole (XV) showed excellent CNS depressant activities. The result of the present investigation may encourage us to develop and/or improve similar other related compounds and it may be assumed that further modifications may produce compounds of better activity with lesser side effects.