Analysis of Transcripts Expressed in One-Day-Old Larvae and Fifth Instar Silk Glands of Tasar Silkworm, Antheraea mylitta

Antheraea mylitta is one of the wild nonmulberry silkworms, which produces tasar silk. An EST project has been undertaken to understand the gene expression profile of A. mylitta silk gland. Two cDNA libraries, one from the whole bodies of one-day-old larvae and the other from the silkglands of fifth instar larvae, were constructed and sequenced. A total of 2476 good-quality ESTs (1239 clones) were obtained and grouped into 648 clusters containing 390 contigs and 258 singletons to represent 467 potential unigenes. Forty-five sequences contained putative coding region, and represented potentially novel genes. Among the 648 clusters, 241 were categorized according to Gene Ontology hierarchy and showed presence of several silk and immune-related genes. The A. mylitta ESTs have been organized into a freely available online database “AmyBASE”. These data provide an initial insight into the A. mylitta transcriptome and help to understand the molecular mechanism of silk protein production in a Lepidopteran species

Ligand-induced segregation from large cell-surface phosphatases is a critical step in γδ TCR triggering

Gamma/delta (γδ) T cells are unconventional lymphocytes that recognize diverse ligands via somatically recombined T cell antigen receptors (γδ TCRs). The molecular mechanism by which ligand recognition initiates γδ TCR signaling, a process known as TCR triggering, remains elusive. Unlike αβ TCRs, γδ TCRs are not mechanosensitive and do not require co-receptors or typical binding-induced conformational changes for triggering. Here, we show that γδ TCR triggering by nonclassical MHC class Ib antigens, a major class of ligands recognized by γδ T cells, requires steric segregation of the large cell-surface phosphatases CD45 and CD148 from engaged TCRs at synaptic close-contact zones. Increasing access of these inhibitory phosphatases to sites of TCR engagement, by elongating MHC class Ib ligands or truncating CD45/148 ectodomains, abrogates TCR triggering and T cell activation. Our results identify a critical step in γδ TCR triggering and provide insight into the core triggering mechanism of endogenous and synthetic tyrosine-phosphorylated immunoreceptors

Inheritance and relationships of flowering time and seed size in kabuli chickpea

Flowering time and seed size are the important traits for adaptation in chickpea. Early phenology (time of flowering, podding and maturity) enhance chickpea adaptation to short season environments. Along with a trait of consumer preference, seed size has also been considered as an important factor for subsequent plant growth parameters including germination, seedling vigour and seedling mass. Small seeded kabuli genotype ICC 16644 was crossed with four genotypes (JGK 2, KAK 2, KRIPA and ICC 17109) to study inheritance of flowering time and seed size. The relationships of phenology with seed size, grain yield and its component traits were studied. The study included parents, F1, F2 and F3 of four crosses. The segregation data of F2 indicated flowering time in chickpea was governed by two genes with duplicate recessive epistasis and lateness was dominant to earliness. Two genes were controlling 100-seed weight where small seed size was dominant over large seed size. Early phenology had significant negative or no association (ICC 16644 × ICC 17109) with 100-seed weight. Yield per plant had significant positive association with number of seeds per plant, number of pods per plant, biological yield per plant, 100-seed weight, harvest index and plant height and hence could be considered as factors for seed yield improvement. Phenology had no correlation with yield per se (seed yield per plant) in any of the crosses studied. Thus, present study shows that in certain genetic background it might be possible to breed early flowering genotypes with large seed size in chickpea and selection of early flowering genotypes may not essentially have a yield penalty

Solvation dynamics of a probe covalently bound to a protein and in an AOT microemulsion: 4-(N-bromoacetylamino)-phthalimide

4-(N-bromoacetylamino)-phthalimide (I) is used as a new solvation probe for protein and microemulsions. The photophysics of the probe 4-(N-bromoacetylamino)-phthalimide (I) is dramatically different from that of the parent compound, 4-aminophthalimide (4-AP). The solvation dynamics of I in an AOT microemulsion is similar to that of 4-AP in microemulsions. Solvation dynamics in the vicinity of a protein glutaminyl-tRNA synthetase (GlnRS) is studied by covalently attaching I to the protein. The solvation dynamics of the protein-bound probe is described by a very fast component of 40 ps and another of 580 ps

Molecular characterization of genome segment 2 encoding RNA dependent RNA polymerase of Antheraea mylitta cytoplasmic polyhedrosis virus

AbstractGenome segment 2 (S2) from Antheraea mylitta cypovirus (AmCPV) was converted into cDNA, cloned and sequenced. S2 consisted of 3798 nucleotides with a long ORF encoding a 1116 amino acid long protein (123kDa). BLAST and phylogenetic analysis showed 29% sequence identity and close relatedness of AmCPV S2 with RNA dependent RNA polymerase (RdRp) of other insect cypoviruses, suggesting a common origin of all insect cypoviruses. The ORF of S2 was expressed as 123kDa soluble His-tagged fusion protein in insect cells via baculovirus recombinants which exhibited RdRp activity in an in vitro RNA polymerase assay without any intrinsic terminal transferase activity. Maximum activity was observed at 37°C at pH 6.0 in the presence of 3mM MgCl2. Site directed mutagenesis confirmed the importance of the conserved GDD motif. This is the first report of functional characterization of a cypoviral RdRp which may lead to the development of anti-viral agents

Crystal structure of a fungal protease inhibitor from Antheraea mylitta

Indian tasar silk is produced by a wild insect called Antheraea mylitta. Insects do not have any antigen-antibody mediated immune system like vertebrates but they produce a wide variety of effector proteins and peptides possessing potent antifungal and antibacterial activity to combat microbial attack. Antheraea mylitta expresses a fungal protease inhibitor AmFPI-1, in the hemolymph that inhibits alkaline protease of Aspergillus oryzae for protection against fungal infection. AmFPI-1 is purified from the hemolymph, crystallized and the structure is solved using the single isomorphous replacement with anomalous scattering (SIRAS) method to a resolution of 2.1 Å. AmFPI-1 is a single domain protein possessing a unique fold that consists of three helices and five β strands stabilized by a network of six disulfide bonds. The reactive site of AmFPI-1 is located in the loop formed by residues 46-66, wherein Lys54 is the P1 residue. Superimposition of the loop with reactive sites of other canonical protease inhibitors shows that reactive site conformation of AmFPI-1 is similar to them. The structure of AmFPI-1 provides a framework for the docking of a 1:1 complex between AmFPI-1 and alkaline protease. This study addresses the structural basis of AmFPI-1's specificity towards a fungal serine protease but not to mammalian trypsin and may help in designing specific inhibitors against fungal proteases

A Comparative Analysis of Studies on Heat Transfer and Fluid Flow in Microchannels

The extremely high rates of heat transfer obtained by employing microchannels makes them an attractive alternative to conventional methods of heat dissipation, especially in applications related to the cooling of microelectronics. A compilation and analysis of the results from investigations on fluid flow and heat transfer in micro- and mini-channels and microtubes in the literature is presented in this review, with a special emphasis on quantitative experimental results and theoretical predictions. Anomalies and deviations from the behavior expected for conventional channels, both in terms of the frictional and heat transfer characteristics, are discussed