Non-Apis bee diversity in an experimental pollinator garden in Bengaluru – a Silicon Valley of India

Necessity of pollinators in ecosystem services and their decline has raised concern for their conservation both in farm lands and urban areas. With the aim of conservation of these pollinators, we initiated developing a pollinator garden at Yelahanka Campus of ICAR-National Bureau of Agricultural Insect Resources in an area of one acre by planting over 50 diverse plant species. Thirty-nine different species of bees were documented from the flora of the pollinator garden. Out of the thirty-nine species of bees, nineteen species of bees belong to non-apis families viz., Megachilidae and Halictidae. Apart from foraging on the flowers, the solitary bees like Megachile sp. were found nesting in the stems, fallen dried flowers in the pollinator garden. The bees were found year-round foraging upon the flora in the pollinator garden. Pollinator garden is a way to in-situ conserve the native bees to sustain the valuable pollination service in various crop plants provided by them.

Foraging specificity of Tetralonia (Thygatina) macroceps (Hymenoptera: Apidae: Anthophorinae) on Argyreia cuneata (Convolvulaceae)

Floral specificity is a behavior that evolved due to mutualistic interactions between the plant-pollinator community. Flowers advertise themselves using visual or chemical cues to attract pollinators and gain reproductive success through pollination. Pollinators forage for rewards such as nectar or pollen produced by the flowers. We found that an anthophorid bee, Tetralonia macroceps, foraged specifically on Argyreia cuneata flowers. No visitation was observed on the flowers of A. nervosa though both belong to Convolvulaceae. T. macroceps was the most abundant floral visitor (5.21 bees/flower/5 min) on A. cuneata and did not visit A. nervosa. Mass flowering and narrow tubular flower structure with easy access to pollen in A. cuneata were the traits that accounted for the foraging specificity of T. macroceps. The present study investigates the preference of T. macroceps for the flowers and floral extracts of A. cuneata and A. nervosa. The bee visited 10.16 flowers/5 min of A. cuneata. T. macroceps were highly attracted to the flowers of A. cuneata. No bees were attracted to A. nervosa. The floral abundance of A. cuneata was relatively higher compared to A. nervosa. Pollen analysis of foraging bees of T. macroceps revealed the selective preference towards the pollen of A. cuneata. The highest number of bees preferred the extract of A. cuneata (7.75) compared to A. nervosa (0.50) in the Y-olfactory maze. Floral extract of A. cuneata caused the highest neuronal electroantennogram (EAG) response (1.48 mV) than A. nervosa (0.36 mV). Our preliminary studies indicated the presence of specific volatile organic compounds (VOCs) nonacosane (13.26%), hexatriacontane (12.06%), and beta farnesene (6.19%) observed in A. cuneata were absent in congener A. nervosa

FoldAffinity: Binding affinities from nDSF experiments

Differential scanning fluorimetry (DSF) using the inherent fluorescence of proteins (nDSF) is a popular technique to evaluate thermal protein stability in different conditions (e.g. buffer, pH). In many cases, ligand binding increases thermal stability of a protein and often this can be detected as a clear shift in nDSF experiments. Here, we evaluate binding affinity quantification based on thermal shifts. We present four protein systems with different binding affinity ligands, ranging from nM to high μM. Our study suggests that binding affinities determined by isothermal analysis are in better agreement with those from established biophysical techniques (ITC and MST) compared to apparent Kds obtained from melting temperatures. In addition, we describe a method to optionally fit the heat capacity change upon unfolding (Δ Cp) during the isothermal analysis. This publication includes the release of a web server for easy and accessible application of isothermal analysis to nDSF data.Fil: Niebling, Stephan. Centre for Structural Systems Biology; Alemania. European Molecular Biology Laboratory; AlemaniaFil: Burastero, Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina. European Molecular Biology Laboratory; AlemaniaFil: Bürgi, Jérôme. European Molecular Biology Laboratory; AlemaniaFil: Günther, Christian. European Molecular Biology Laboratory; AlemaniaFil: Defelipe, Lucas Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. European Molecular Biology Laboratory; AlemaniaFil: Sander, Simon. Universitat Hamburg; AlemaniaFil: Gattkowski, Ellen. Universitat Hamburg; AlemaniaFil: Anjanappa, Raghavendra. Universitat Bremen. School of Engineering and Science Jacobs; AlemaniaFil: Wilmanns, Matthias. European Molecular Biology Laboratory; Alemania. Universitat Hamburg; AlemaniaFil: Springer, Sebastian. Universitat Bremen. School of Engineering and Science Jacobs; AlemaniaFil: Tidow, Henning. Universitat Hamburg; AlemaniaFil: García Alai, María. European Molecular Biology Laboratory; Alemania. Centre for Structural Systems Biology; Alemani

Acetylcholinesterase inhibition by biofumigant (Coumaran) from leaves of Lantana camara in stored grain and household insect pests

Recent studies proved that the biofumigants could be an alternative to chemical fumigants against stored grain insect pests. For this reason, it is necessary to understand the mode of action of biofumigants. In the present study the prospectus of utilising Lantana camara as a potent fumigant insecticide is being discussed. Inhibition of acetylcholinesterase (AChE) by Coumaran, an active ingredient extracted from the plant L. camara, was studied. The biofumigant was used as an enzyme inhibitor and acetylthiocholine iodide as a substrate along with Ellman's reagent to carry out the reactions. The in vivo inhibition was observed in both dose dependent and time dependent in case of housefly, and the nervous tissue (ganglion) and the whole insect homogenate of stored grain insect exposed to Coumaran. The possible mode of action of Coumaran as an acetylcholinesterase inhibitor is discussed

Fractographic analysis of tensile failures of aerospace grade composites

This paper describes fractographic features observed in aerospace composites failed under tensile loads. Unidirectional Carbon Fibre Reinforced Plastic (UD CFRP) and Unidirectional Glass Fibre Reinforced Plastic (UD GFRP) composite specimens were fabricated and tested in tension. The morphology of fractured surfaces was studied at various locations to identify failure mechanism and characteristic fractographic features. CFRP composites displayed transverse crack propagation and the fracture surface showed three distinct regions, viz., crack origin, propagation and final failure. Significant variations in the fractographic features were noticed in crack propagation and final failure regions. Crack propagation region exhibited brittle fracture with chevron lines emanating from the crack origin. The entire crack propagation region exhibited radial marks on the individual fibre broken ends. On the other hand, the final fracture region revealed longitudinal matrix splitting and radial marks in majority of locations, and chop marks at some locations. The change in fracture mode in the final fracture was attributed to superimposition of bending loads. GFRP composites exhibited broom like fracture with extensive longitudinal splitting with radial marks present on individual fibre broken ends. Transverse fracture was observed at a few locations. These fracture features were analyzed and correlated with the loading conditions

Opening opportunities for Kd determination and screening of MHC peptide complexes

An essential element of adaptive immunity is selective binding of peptide antigens by major histocompatibility complex (MHC) class I proteins and their presentation to cytotoxic T lymphocytes. Using native mass spectrometry, we analyze the binding of peptides to an empty disulfide-stabilized HLA-A*02:01 molecule and, due to its unique stability, we determine binding affinities of complexes loaded with truncated or charge-reduced peptides. We find that the two anchor positions can be stabilized independently, and we further analyze the contribution of additional amino acid positions to the binding strength. As a complement to computational prediction tools, our method estimates binding strength of even low-affinity peptides to MHC class I complexes quickly and efficiently. It has huge potential to eliminate binding affinity biases and thus accelerate drug discovery in infectious diseases, autoimmunity, vaccine design, and cancer immunotherapy

Structures of peptide-free and partially loaded MHC class I molecules reveal mechanisms of peptide selection

Major Histocompatibility Complex (MHC) class I molecules selectively bind peptides for presentation to cytotoxic T cells. The peptide-free state of these molecules is not well understood. Here, we characterize a disulfide-stabilized version of the human class I molecule HLA-A*02:01 that is stable in the absence of peptide and can readily exchange cognate peptides. We present X-ray crystal structures of the peptide-free state of HLA-A*02:01, together with structures that have dipeptides bound in the A and F pockets. These structural snapshots reveal that the amino acid side chains lining the binding pockets switch in a coordinated fashion between a peptide-free unlocked state and a peptide-bound locked state. Molecular dynamics simulations suggest that the opening and closing of the F pocket affects peptide ligand conformations in adjacent binding pockets. We propose that peptide binding is co-determined by synergy between the binding pockets of the MHC molecule