In many species, genomic data have revealed pervasive adaptive evolution indicated by the fixation of beneficial alleles. However, when selection pressures are highly variable along a species' range or through time adaptive alleles may persist at intermediate frequencies for long periods. So called “balanced polymorphisms” have long been understood to be an important component of standing genetic variation, yet direct evidence of the strength of balancing selection and the stability and prevalence of balanced polymorphisms has remained elusive. We hypothesized that environmental fluctuations among seasons in a North American orchard would impose temporally variable selection on Drosophila melanogaster that would drive repeatable adaptive oscillations at balanced polymorphisms. We identified hundreds of polymorphisms whose frequency oscillates among seasons and argue that these loci are subject to strong, temporally variable selection. We show that these polymorphisms respond to acute and persistent changes in climate and are associated in predictable ways with seasonally variable phenotypes. In addition, our results suggest that adaptively oscillating polymorphisms are likely millions of years old, with some possibly predating the divergence between D. melanogaster and D. simulans. Taken together, our results are consistent with a model of balancing selection wherein rapid temporal fluctuations in climate over generational time promotes adaptive genetic diversity at loci underlying polygenic variation in fitness related phenotypes.

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Genomic evidence of rapid and stable adaptive oscillations over seasonal time scales in Drosophila.

Geographic Variation, Speciation, and Clines.

Human exposure to neonicotinoid insecticides and the evaluation of their potential toxicity: An overview.

New information on the lethal and sublethal effects of neonicotinoids and fipronil on organisms is presented in this review, complementing the previous Worldwide Integrated Assessment (WIA) in 2015. The high toxicity of these systemic insecticides to invertebrates has been confirmed and expanded to include more species and compounds. Most of the recent research has focused on bees and the sublethal and ecological impacts these insecticides have on pollinators. Toxic effects on other invertebrate taxa also covered predatory and parasitoid natural enemies and aquatic arthropods. Little new information has been gathered on soil organisms. The impact on marine and coastal ecosystems is still largely uncharted. The chronic lethality of neonicotinoids to insects and crustaceans, and the strengthened evidence that these chemicals also impair the immune system and reproduction, highlights the dangers of this particular insecticidal class (neonicotinoids and fipronil), with the potential to greatly decrease populations of arthropods in both terrestrial and aquatic environments. Sublethal effects on fish, reptiles, frogs, birds, and mammals are also reported, showing a better understanding of the mechanisms of toxicity of these insecticides in vertebrates and their deleterious impacts on growth, reproduction, and neurobehaviour of most of the species tested. This review concludes with a summary of impacts on the ecosystem services and functioning, particularly on pollination, soil biota, and aquatic invertebrate communities, thus reinforcing the previous WIA conclusions (van der Sluijs et al. 2015).

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An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems.

Well, someone can decide by themselves what they want to do and need to do but sometimes, that kind of person will need some chemical mutagens principles and methods for their detection volume 2 references. People with open minded will always try to seek for the new things and information from many sources. On the contrary, people with closed mind will always think that they can do it by their principals. So, what kind of person are you?

Chemical Mutagens. Principles and Methods for Their Detection

Aerial parts of Eclipta alba are used traditionally for the treatment of several diseases of liver, skin and stomach. Methanolic extract and active principle compound of a well known Indian hepatoprotective herb, Eclipta alba was tested for in vitro antimicrobial studies. It was evaluated using zone of inhibition studies and minimum inhibitory concentration. The extract exhibited activity against all six strains studied. Phytochemical screening of the extract revealed the presence of tannins, flavonoids, coumestans, saponins and alkaloids etc. Ethylacetate fraction and further pure isolated wedelolactone showed enhanced antimicrobial activity. Staphylococcus epidermidis, Staphylococcus aureus and Salmonella typhimurium were most susceptible. Shigella flexneri was the most resistant bacterial strain. These results suggest coumestans/wedelolactone as a promising antimicrobial agent.

/pdf/phytochemical-screening-of-methanolic-extract-and-1qnba0o776.pdf

Phytochemical Screening of Methanolic Extract and Antibacterial Activity of Active Principles of Hepatoprotective Herb, Eclipta alba

Imidacloprid (IMD), 1(6-chloro-3-pyridinyl)methyl)-N-nitro-2-imidazolidinimine, was administered in female mice to study in vivo cytogenetic (chromosomal aberrations (CAs) and micronucleus assay) and hematological effects. The acute oral LD50 was determined to be 150 mg/kg bw in mice following OECD guidelines using AOT StatPgm425 software. The mice were administered orally with distilled water (negative control); mitomycin C (MMC), 1 mg/kg (positive control) and sub-lethal doses of 37.5 (low), 75.0 (medium) and 112.5 (high) mg/kg bw (25%, 50% and 75% of LD50) of IMD to analyze CAs and hematological effects after 24 h, whereas micronucleus test (MT) after 48 h. The genotoxicity analysis revealed that selected test doses of IMD--medium and high doses--induced significantly mitotic inhibition (p < 0.01), CAs (p < 0.01) and at high dose micronucleus (MN) formation (p < 0.05). Significant changes in red blood cell (RBC; p < 0.01), hemoglobin (Hb; p < 0.01) and erythrocyte sedimentation rate (ESR; p < 0.001) were observed, except WBC in which significant increase (p < 0.001) was observed. Present observation substantiates overall significant dose dependent genotoxic potential (p < 0.05; r = 0.98) of IMD. Precautions should be taken to minimize possible risk to exposed farmers of the state of Haryana (India)--an agrarian economy.

Cytogenetic and hematological alterations induced by acute oral exposure of imidacloprid in female mice.

A review on ameliorative green nanotechnological approaches in diabetes management.

We have measured alpha-particle spectra at different laboratory angles from the fusion reaction Si-28+V-51 at 140 MeV. These spectra deviate at higher energies from the statistical model calculations using rotating liquid drop model values of the moment of inertia. In order to explain the experimental spectra, changes were required in the moments of inertia corresponding to deformation, which suggests dynamical effects on the deexcitation process for charged-particle emission. The comparison of decay times with formation times implies that light charged particles are preferentially emitted prior to the full relaxation of the compound nucleus. Statistical models and dynamical calculations have been employed in an attempt to interpret the experimental data. The results were compared with the Si-28+Al-27 system studied earlier in order to understand the symmetric and asymmetric entrance channel effects in the formation of the compound system.

α-particle emission as a probe of dynamical deformations

Obesity is a serious health complication in almost every corner of the world. Excessive weight gain results in the onset of several other health issues such as type II diabetes, cancer, respiratory diseases, musculoskeletal disorders (especially osteoarthritis), and cardiovascular diseases. As allopathic medications and derived pharmaceuticals are partially successful in overcoming this health complication, there is an incessant need to develop new alternative anti-obesity strategies with long term efficacy and less side effects. Plants harbor secondary metabolites such as phenolics, flavonoids, terpenoids and other specific compounds that have been shown to have effective anti-obesity properties. Nanoencapsulation of these secondary metabolites enhances the anti-obesity efficacy of these natural compounds due to their speculated property of target specificity and enhanced efficiency. These nanoencapsulated and naive secondary metabolites show anti-obesity properties mainly by inhibiting the lipid and carbohydrate metabolizing enzymes, suppression of adipogenesis and appetite, and enhancing energy metabolism. This review focuses on the plants and their secondary metabolites, along with their nanoencapsulation, that have anti-obesity effects, with their possible acting mechanisms, for better human health.

Sudhir Kumar Kataria

Papers

Phytochemical Screening of Methanolic Extract and Antibacterial Activity of Active Principles of Hepatoprotective Herb, Eclipta alba

Cytogenetic and hematological alterations induced by acute oral exposure of imidacloprid in female mice.

A review on ameliorative green nanotechnological approaches in diabetes management.

α-particle emission as a probe of dynamical deformations

A Review on Obesity Management through Natural Compounds and a Green Nanomedicine-Based Approach