Chemical constituents and strong larvicidal activity of Solanum xanthocarpum among selected plants extracts against the malaria, filaria, and dengue vectors.

BACKGROUND & OBJECTIVES: The role of mosquitoes is instrumental in the transmission of various diseases. Mosquitoe-borne diseases account for a significant share of the global burden of total infectious diseases. Vector control is the principal method for the control of these mosquito-borne diseases. Plant-derived insecticides serve as an effective alternative to chemical insecticides. The present study has been undertaken to assess the larvicidal potential of methanol and petroleum ether extracts of leaves of Solanum xanthocarpum, Parthenium hysterophorus, Manihot esculenta, and Chamaecyparis obtusa. METHODS: Larvicidal activity was tested against the early four-stage instar larvae of laboratory-reared susceptible strains of the malaria vector, Anopheles stephensi, dengue fever vector, Aedes aegypti, and the lymphatic filariasis vector, Culex quinquefasciatus at 20 to 120 ppm concentrations. Further, liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectroscopy (GC-MS) analyses were carried out to identify the bioactive compounds present in the methanolic leaf extracts of Solanum xanthocarpum for designing a larvicidal product in future. RESULTS: After 72 h of exposure high larvicidal activities were observed in methanolic and petroleum ether leaves extract of S. xanthocarpum against An. stephensi, Ae. aegypti and Cx. quinquefasciatus. The larvicidal activities for methanol and petroleum ether leaf extract of S. xanthocarpum with LC50 = 09.201 and 12.435 ppm and LC90 = 21.578 and 27.418 ppm for An. stephensi; LC50 = 11.450 and 10.026 ppm and LC90 = 26.328 and 22.632 ppm for Ae. aegypti and LC50 = 12.962 and 13.325 ppm and LC90 = 26.731 and 30.409 ppm for Cx. quinquefasciatus, respectively, were found to be most effective. GC-MS analysis revealed 43 compounds, amongst these phytol (13.09%), 3-allyl-2-methoxy phenol (9.55%), (9Z, 12Z)-9, 12-octadecadienoyl chloride (7.93%), linoleic acid (5.45%), alpha-tocospiro B (5.08%) and hexadecanoic acid (4.35%) were identified as major compounds. INTERPRETATION & CONCLUSION: Present work showed that leaf extracts of S. xanthocarpum are a source of potential natural candidate that possess several phytochemicals which can be explored further for the development of ecologically safer mosquito control products.

Mitigation of salt stress in lettuce by a biostimulant that protects the root absorption zone and improves biochemical responses.

Horticultural crops constantly face abiotic stress factors such as salinity, which have intensified in recent years due to accelerated climate change, significantly affecting their yields and profitability. Under these conditions, it has become necessary to implement effective and sustainable solutions to guarantee agricultural productivity and food security. The influence of BALOX®, a biostimulant of plant origin, was tested on the responses to salinity of Lactuca sativa L. var. longifolia plants exposed to salt concentrations up to 150 mM NaCl, evaluating different biometric and biochemical properties after 25 days of treatment. Control plants were cultivated under the same conditions but without the biostimulant treatment. An in situ analysis of root characteristics using a non-destructive, real-time method was also performed. The salt stress treatments inhibited plant growth, reduced chlorophyll and carotenoid contents, and increased the concentrations of Na+ and Cl- in roots and leaves while reducing those of Ca2+. BALOX® application had a positive effect because it stimulated plant growth and the level of Ca2+ and photosynthetic pigments. In addition, it reduced the content of Na+ and Cl- in the presence and the absence of salt. The biostimulant also reduced the salt-induced accumulation of stress biomarkers, such as proline, malondialdehyde (MDA), and hydrogen peroxide (H2O2). Therefore, BALOX® appears to significantly reduce osmotic, ionic and oxidative stress levels in salt-treated plants. Furthermore, the analysis of the salt treatments' and the biostimulant's direct effects on roots indicated that BALOX®'s primary mechanism of action probably involves improving plant nutrition, even under severe salt stress conditions, by protecting and stimulating the root absorption zone.

Virtual screening of gut microbiome bacteriocins as potential inhibitors of stearoyl-CoA desaturase 1 to regulate adipocyte differentiation and thermogenesis to combat obesity.

The gut bacterial strains and their metabolites have been shown to play a significant role in obesity, but the molecular mechanisms underlying this association are largely unresolved. Obesity is a multifactorial problem and is controlled by various mechanisms and pathways to produce and store fat cells. Bacteriocins are secondary metabolites produced by gut bacteria to defend themselves against their competitors. Recently, they have gained great attention due to their role in metabolic disorders, including obesity. Stearoyl-CoA desaturase 1 (SCD1) is a key enzyme involved in the differentiation of adipocytes. The aim of this study is to show the regulation of SCD1 by bacteriocins and thus their importance in obesity control. We screened the human gut bacteriome for the presence of bacteriocins, predicted their structures, and showed their inhibitory role by molecular docking with SCD1. Further, to confirm the docking results, MDS of six top scoring SCD1-bacteriocin complexes were carried out for 100 ns. These six bacteriocins namely, Plantaricin S-beta, Carnolysin, Lactococcin B, Bacteriocin Iic, Plantaricin N, and Thermophilin A, with strong binding affinities, are primarily produced by bacterial strains from the Lactobacillaeacea family. These findings can be the basis of further experiments for enhanced understanding of the underlying mechanisms for obesity control, specifically bacteriocins driven regulation of the SCD1 enzyme. In addition, a consortium of bacterial strains producing these bacteriocins can be developed and used as probiotics for the amelioration of obesity and other metabolic complications.Communicated by Ramaswamy H. Sarma.

Evaluation of Drought Responses in Two Tropaeolum Species Used in Landscaping through Morphological and Biochemical Markers.

One of the most important challenges horticultural crops confront is drought, particularly in regions such as the Mediterranean basin, where water supplies are usually limited and will become even scarcer due to global warming. Therefore, the selection and diversification of stress-tolerant cultivars are becoming priorities of contemporary ornamental horticulture. This study explored the impact of water stress on two Tropaeolum species frequently used in landscaping. Young plants obtained by seed germination were exposed to moderate water stress (half the water used in the control treatments) and severe water stress (complete withholding of irrigation) for 30 days. Plant responses to these stress treatments were evaluated by determining several growth parameters and biochemical stress markers. The latter were analysed by spectrophotometric methods and, in some cases, by non-destructive measurements using an optical sensor. The statistical analysis of the results indicated that although the stress responses were similar in these two closely related species, T. minus performed better under control and intermediate water stress conditions but was more susceptible to severe water stress. On the other hand, T. majus had a stronger potential for adaptation to soil water scarcity, which may be associated with its reported expansion and naturalisation in different regions of the world. The variations in proline and malondialdehyde concentrations were the most reliable biochemical indicators of water stress effects. The present study also showed a close relationship between the patterns of variation of flavonoid and chlorophyll contents obtained by sensor-based and spectrophotometric methods.

A comparative analysis of the distribution and composition of lipidic constituents and associated enzymes in pollen and stigma of sunflower.

Spatial distribution and compositional analyses of the lipidic constituents in pollen and stigma of sunflower (Helianthus annuus L. cv. Morden) were conducted using ultrastructural, histochemical, and biochemical analysis. Detection of secretions at the base of stigmatic papillae and neutral lipid accumulations on the surface of stigmatic papillae and between adjacent pseudopapillae demonstrates the semidry nature of stigma surface in sunflower. Pollen coat is richer in lipids (8%) than stigma (2.2%) on fresh weight basis. Nile Red-fluorescing neutral lipids are preferentially localized in the pollen coat. Neutral esters and triacylglycerols (TAGs) are the major lipidic constituents in pollen grains and stigma, respectively. Lignoceric acid (24:0) and cis-11-eicosenoic acid (20:1) are specifically expressed only in the pollen coat. Similar long-chain fatty acids have earlier been demonstrated to play a significant role during the initial signaling mechanism leading to hydration of pollen grains on the stigma surface. Lipase (EC 3.1.1.3) activity is expressed both in pollen grains and stigma. Stigma exhibits a better expression of acyl-ester hydrolase (EC 3.1.1.1) activity than that of observed in both the pollen fractions. Expression of two acyl-ester hydrolases (41 and 38 kDa) has been found to be specific to pollen coat. Specific expression of lignoceric acid (24:0) in pollen coat and localization of lipase in pollen and stigma have been discussed to assign possible roles that they might play during pollen-stigma interaction.