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Ravikumar G.,Seri biotech Research Laboratory | Vardhana K.V.,Seri biotech Research Laboratory | Basavaraja H.K.,Seri biotech Research Laboratory
Journal of Insect Science | Year: 2011

In an earlier report, we described the gene encoding a lipophorin receptor (LpR) of the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), and recombinant expression of the protein. The present study was performed to characterize the corresponding native BmLpR and its binding characteristics. Polyclonal anti-LpR antibody prepared against the cloned receptor fragment from the cytoplasmic domain specifically detected the receptor. Through immunoblotting, ovary and brain membrane protein samples of BmLpR have shown an apparent molecular mass of 105 kDa and 120 kDa under nonreducing and reducing conditions, respectively. Ligand binding of LpR supported the immunoblot results. It bound to high density lipophorin (HDLp) and has shown requirement of Ca 2+ in binding. Further, a dose-dependent inhibition by EDTA was observed in receptor ligand binding. The characteristics of the BmLpR protein confirm the properties of a ligand-receptor interaction similar to that of vertebrate low density lipoprotein receptor (LDLR). Source

Vijayan K.,Seri biotech Research Laboratory | Vijayan K.,Academia Sinica, Taiwan | Nair C.V.,Seri biotech Research Laboratory | Urs R.S.,Seri biotech Research Laboratory
Emirates Journal of Food and Agriculture | Year: 2010

Genetic diversity among 13 tropical nondiapausing silkworm (Bombyx mori L.) genotypes was estimated with simple sequence repeats (SSRs) and mitochondrial DNA (mtDNA)- single strand conformation polymorphism (SSCP) markers. Seven SSR primers from silkworm genome and the eight mtDNA primers from the conserved regions of 16S and 12S ribosomal RNA, cytochrome oxidase I, II and III, and cytochrome B revealed considerable genetic distance among the 13 silkworm genotypes. The heterozygosity generated by the seven pairs of SSR primers varied from 0.098 to 0.396. The eight pairs of mtDNA primers developed 2 to 10 haplotypes per primer sets. The dendrogram from these markers grouped the silkworm genotypes into different groups, from which potential parents could be selected for developing hybrids for commercial exploitations. Based on cocoon characters and the genetic diversity analysis, Kollegal Jawan was identified as a parent that can be crossed with either BL-23 or Mysore Princess for developing high yielding silkworms to rear commercially during summer and rain seasons. Source

Lekha G.,Seri biotech Research Laboratory | Gupta T.,Seri biotech Research Laboratory | Trivedy K.,Seri biotech Research Laboratory | Ponnuvel K.,Seri biotech Research Laboratory
Invertebrate Survival Journal | Year: 2015

The genomic organization, structure and polymorphism of attacin gene within the mulberry silkworm Bombyx mori strains have been analyzed. Genomic contig (AADK01007556) of B. mori attacin gene contains locus with two transcribed basic attacin genes, which were designated as attacin I and attacin II. Survey of the naturally occurring genetic variation in different strains of silkworm B. mori at the promoter and coding regions of two attacin genes revealed high levels of silent nucleotide variations (1- 4 % per nucleotide heterozygosity) without polymorphism at the amino acid level (non-Synonymous substitution). We also investigated variations in gene expression of attacin I and attacin II in silkworm B. mori infected with nucleopolyhedrovirus (BmNPV). Two B. mori strains, Sarupat, CSR-2 which were resistant and susceptible to BmNPV infection respectively were used in this study. Expression profiles of B. mori genes were analyzed using microarray technique and results revealed that the immune response genes including attacin were selectively up regulated in virus invaded midguts of both races. Microarray data and real-time qPCR results revealed that attacin I gene was significantly up-regulated in the midgut of Sarupat following BmNPV infection, indicating its specific role in the anti-viral response. Our results imply that these up-regulated attacin genes were not only involved in anti-bacterial mechanism, but are also involved in B. mori immune response against BmNPV infection. © 2015, Universita degli Studi di Modena e Reggio Emilia. All rights reserved. Source

Ravikumar G.,Seri biotech Research Laboratory | Raje Urs S.,Seri biotech Research Laboratory | Vijaya Prakash N.B.,Seri biotech Research Laboratory | Rao C.G.P.,Seri biotech Research Laboratory | Vardhana K.V.,Seri biotech Research Laboratory
Journal of Invertebrate Pathology | Year: 2011

We have developed a novel PCR-based assay for individual and simultaneous detection of three major pathogens (microsporidians, nucleopolyhedrovirus (NPV) and densovirus (DNV)) infecting the silkworm, Bombyx mori. Multiplex PCR, using three primer pairs, two of which were designed from the conserved regions of 16S small subunit ribosomal RNA gene of microsporidians, and polyhedrin gene of NPVs respectively, and a third primer pair designed from the internal sequences of B. mori DNVs (BmDNV), showed discrete and pathogen specific PCR products. The assay showed high specificity and sensitivity for the pathogenic DNA. Under optimized PCR conditions, the assay yielded a 794. bp DNA fragment from Nosema bombycis, 471. bp fragment from B. mori NPV (BmNPV) and 391. bp fragment from BmDNV. Further, this detection method was successfully applied to other silkworm species such as Antheraea mylitta and Samia cynthia ricini, in detecting same or similar pathogens infecting them. This method is a valuable supplement to the conventional microscopic diagnostic methods and can be used for the early detection of pathogens infecting silkworms. Furthermore it can assist research and extension centers for the safe supply of disease-free silkworms to farmers. © 2011 Elsevier Inc. Source

Gopalapillai R.,Seri biotech Research Laboratory | Vasantkumar V.K.,Seri biotech Research Laboratory | Bala R.,Seri biotech Research Laboratory | Modala V.,Seri biotech Research Laboratory | And 2 more authors.
Journal of Molecular Recognition | Year: 2014

The silkworm, Bombyx mori lipophorin receptor (BmLpR), is expressed as splice variants. The alternative splicing of its primary gene transcripts yields four isoforms namely, LpR1 through 4. Among these isoforms, the LpR4 is unique, expressed only in the brain and CNS and with a unique amino acid tail sequence in its cytoplasmic domain. We carried out yeast two-hybrid screens to identify effector proteins that interact specifically with the cytoplasmic tail of LpR4 from a cDNA library derived from silkworm brain. The validity of the screen was confirmed by immunoblotting and further by co-immunoprecipitation. We have identified 11 novel proteins that are capable of interacting with the cytoplasmic domain of LpR4 in the silkworm brain. Most of these newly identified target proteins have known functions in lipid signalling, protein kinase pathways, cell motility, and organization of cytoskeleton, neurotransmission, and neuroprotection. These findings, for the first time, demonstrate a molecular link between LpR4 and the interacting proteins that might be involved in the regulation of signalling pathways in silkworm brain. Copyright © 2014 John Wiley & Sons, Ltd. IP of a lipophorin receptor with interacting proteins demonstrates a possible link in the regulation of signalling pathways in the silkworm brain. Copyright © 2014 John Wiley & Sons, Ltd. Source

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