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Silk gland

posted Mar 4, 2011, 8:23 AM by rajesh gk

Title

Changes in growth and lipid profiles of silk gland, mid-gut biochemical composition of silkworm, Bombyx mori L. on exposure to prostaglandin F2alpha.

Authors

Miao YG, Jiang LJ.

Department of Sericulture, College of Animal Sciences, Zhejiang University, Hangzhou 310029, China. miaoyg@zju.edu.cn

Journal

Prostaglandins Other Lipid Mediat. 2003 Jan;70(3-4):331-8.

Abstract

The growth of the silkworm is influenced by the outside and inside environment. Among them, the category of various endocrine hormone of inside is the main factors that adjust the characters such as growth and propagate. In this experiment, we applied different dosage of prostaglandin to the fourth and fifth instar silkworm to observe the effects of prostaglandin F2alpha (PGF2alpha) on silk gland growth, mid-gut biochemical constituents and the lipid profiles of silkworm larva, Bombyx mori L. The weight of the posterior silk gland increased significantly (P < 0.001) by 20-24% after treatment with PGF2alpha. The increase in the lipid profiles except lipase activity suggests that the silk gland had more synthetic activity that might reflect in active spinning of silkworm larva. The changes of total proteins, free amino acids and alkaline phosphatase in mid-gut of control and PGF2alpha treated silkworm, B. mori L. indicate that PGF2alpha favored stimulatory effect on physiology of digestion, absorption and transportation of nutrients which might influence on the growth and development of larva.

Citation

http://www.ncbi.nlm.nih.gov/pubmed/12611497 PMID: 12611497 [PubMed - indexed for MEDLINE]

 

Title

Exogenous prostaglandin F2alpha as a mediator in the regulation of silkworm growth and silk gland genome.

Authors

Miao YG, Nair KS.

Department of Sericulture, College of Animal Sciences, Zhejiang University, Hangzhou-310029, PR China. miaoyg@zju.edu.cn

Journal

Prostaglandins Other Lipid Mediat. 2003 Nov;72(3-4):147-54.

Abstract

Prostaglandins are locally acting hormones that have remarkable variety of physiological functions. They are rapidly synthesized in several types of vertebrate cells as oxygenated metabolites of arachidonic acid in response to various stimuli. In many insect species they are biosynthesized in fat body and hemocytes mainly in response to bacterial infections. In the present study, we administered synthetic analog of prostaglandin F2alpha, the most prominent of the prostaglandins to the 48 h old fifth instar silkworm, Bombyx mori L. at a single dose of 4 microg per larva to study its effects on the larval growth pattern and silk synthesis. The possible role of PGF2alpha at altering the quantum of silk synthesis by controlling the silk gene expression was also studied. The genomic DNA was isolated from the posterior silk gland on Days 5 and 7 of the fifth instar from the prostaglandin treated and the control larvae and were random amplified with arbitrary primers. The result presented notable variation in the amplified product suggesting the participation of PGF2alpha in the silk biosynthesis controlling the silk gene expression. The feeding period of treated larvae was unaffected while the cocoon characters exhibited considerable improvement. The filament traits also were improved notably in the treated larvae. The participation of PGF2alpha analog in the silk biosynthetic process with its physiological and molecular implications are discussed.

Citation

http://www.ncbi.nlm.nih.gov/pubmed/14674626 PMID: 14674626 [PubMed - indexed for MEDLINE]

 

Title

A new chitinase-related gene, BmChiR1, is induced in the Bombyx mori anterior silk gland at molt and metamorphosis by ecdysteroid.

Authors

Takahashi M, Kiuchi M, Kamimura M.

Department of Sericulture, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8634, Japan.

Journal

Insect Biochem Mol Biol. 2002 Feb;32(2):147-51.

Abstract

A novel ecdysteroid-inducible gene was isolated from the anterior silk gland of the silkworm by mRNA differential display and named Bombyx mori chitinase-related gene 1 (BmChiR1). cDNA for BmChiR1 is 3.7 kbp encoding 1080 amino acids. Its predicted protein sequence consists of two tandem-repeated sequences, both showing high similarities to arthropod chitinases but lacking the active site glutamate essential for catalytic activity, suggesting that BmChiR1 protein has no chitinolytic activity. BmChiR1 mRNA was expressed simultaneously with chitinase mRNA in the anterior silk gland at the ends of the penultimate and last larval instar. Injection of 20-hydroxyecdysone (20E) into feeding last instar larvae induced accumulation of BmChiR1 mRNA. Topical application of a juvenile hormone analog, fenoxycarb, just after the 20E injection, suppressed this induction. BmChiR1 expression is therefore upregulated by ecdysteroid and downregulated by juvenile hormone.

Citation

http://www.ncbi.nlm.nih.gov/pubmed/11755056 PMID: 11755056 [PubMed - indexed for MEDLINE]

 

Title

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

Authors

Maity S, Goel SI, Roy S, Ghorai S, Bhattacharyya S, Venugopalan A, Ghosh AK.

Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302, India.

Journal

Comp Funct Genomics. 2010:246738. Epub 2010 May 4

Abstract

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.

Citation

PMID: 20454581 [PubMed - in process]PMCID: PMC2864506 Free PMC Article

 

 

Title

Molecular evolution of lepidopteran silk proteins: insights from the ghost moth, Hepialus californicus.

Authors

Collin MA, Mita K, Sehnal F, Hayashi CY.

Department of Biology, University of California, Riverside, CA 92521, USA. matthew.collin@email.ucr.edu

Journal

J Mol Evol. 2010 May;70(5):519-29. Epub 2010 May 11.

Abstract

Silk production has independently evolved in numerous arthropod lineages, such as Lepidoptera, the moths and butterflies. Lepidopteran larvae (caterpillars) synthesize silk proteins in modified salivary glands and spin silk fibers into protective tunnels, escape lines, and pupation cocoons. Molecular sequence data for these proteins are necessary to determine critical features of their function and evolution. To this end, we constructed an expression library from the silk glands of the ghost moth, Hepialus californicus, and characterized light chain fibroin and heavy chain fibroin gene transcripts. The predicted H. californicus silk fibroins share many elements with other lepidopteran and trichopteran fibroins, such as conserved placements of cysteine, aromatic, and polar amino acid residues. Further comparative analyses were performed to determine site-specific signatures of selection and to assess whether fibroin genes are informative as phylogenetic markers. We found that purifying selection has constrained mutation within the fibroins and that light chain fibroin is a promising molecular marker. Thus, by characterizing the H. californicus fibroins, we identified key functional amino acids and gained insight into the evolutionary processes that have shaped these adaptive molecules.

Citation

PMID: 20458474 [PubMed - in process]PMCID: PMC2876269 Free PMC Article

 

 

Title

The silk proteins, sericin and fibroin in silkworm, Bombyx mori Linn., - a review

Authors

Mondal, M.*, Trivedy, K., Nirmal Kumar, S.,

Journal

Caspian J. Env. Sci., 5, 63-76. ( 2007 )

Abstract

The domesticated silkworm, Bombyx mori Linn., a lepidopteran molecular model and an important economic insect that are emerging as an ideal molecular genetic resource for solving a broad range of biological problems. The silkworm, B. mori produces massive amount of silk proteins during the final stage of larval development. These proteins are stored in the middle silk gland and they are discharged through the anterior duct and spinneret, at the end of the fifth instar. Two kinds of silk proteins have been distinguished as major components of silk cocoons, the first being fibroin, a fibrous protein composed of heavy (H) chain, Light (L) chain and glycoprotein linked by disulfide bonds and the second being sericin a natural macromolecular protein, serving as an adhesive to unite fibroin for making silk cocoons of silkworm, B. mori. Recently, silkworm is being used as biofactory for the production of useful protein using the silk gland, which has promoted the technological development in sericulture. With the above background silkworm can be classified as a value added biomaterial for medical application, application of silk protein fibroin and sericin as a biomaterial and other seri-byproducts. The present paper overviews some important studies carried out on sericin and fibroin of silkworm, Bombyx mori Linn.

Citation

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Title

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

Authors

Samita Maity ; Sagar I. Goel ; Sobhan Roy ; Suvankar Ghorai ; Swati Bhattacharyya ; Aravind Venugopalan ; Ananta K. Ghosh

Journal

Comparative and Functional Genomics

Abstract

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 specie

Citation

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