Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SILKWORMS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed2005

[The acquisition of two silkworm CAPs markers and their use in genetic diversity and phylogenetic relationship].

Cleaved amplified polymorphic sequence (CAPs) markers are based on PCR amplification of known genes, cDNA sequences or RAPD sequences. The PCR products are digested by restriction enzymes, generating the simple type of data as heterozygotes and homozygotes. Here we designed primers based on silkworm attacin and alpha-amylase genes, then digested the PCR products in silkworm strains P50, C108 and their progeny F1 using 4 different restriction enzymes respectively. Furthermore, the genetic diversity and phylogenetic relationship of 12 silkworm strains were investigated using the obtained two CAPs markers.

Amplified Fragment Length Polymorphism Analysis↗
PubMed2006

[Emergy analysis of mulberry-silkworm ecosystem in China].

Mulberry-silkworm ecosystem is one of the important agro-ecosystems in China. Based on the principles and methods of emergy analysis, this paper studied the interior structure of mulberry-silkworm ecosystem and its relationship with exterior environment and economy. Some emergy indices for this ecosystem were quantitatively calculated, and compared with those of the agro-ecosystem in China. The results showed that the emergy investment ratio, emergy yield ratio, environmental loading ratio and emergy sustainability index was 3.78, 4.68, 0.18 and 26.0, respectively, suggesting the low environmental pressure and good ecological benefit in mulberry-silkworm ecosystem in China. Hi-technology was required to further decrease the labor force input and enhance the comprehensive utilization of sericultural resources.

Agriculture↗
PubMed1978

[Mutagenic action of dimethyl sulfate and N-nitrosoethylurea on the mulberry silkworm].

Mutagenic effect of chemical mutagens, dimethalsulphate (DMS) and N-nitrosoethyl urea (NEU), on silkworm is studied. The effect of these mutagens have never been studied on silkworm before. DMS is found to be completely insufficient as mutagen for the silkworm, because its low mutability is accompanied with strong cytotoxic effect. NEU appeared to be of "milder" effect. Injection of male-moth proved to be very efficient. The majority of exuded mutants showed mosaic colouring of the graine.

Animals↗
PubMed1984

[Trials using drugs in diseases of the silkworm (Bombyx mori L.)].

Studied was the pharmacokinetic of chloramphenicol, tylosine, ampicillin, and penicillin in silkworm moths. The antibiotics were applied only once in the form of water solutions in concentrations of 0.062 to 1 per cent for chloramphenicol, 50 to 1500 IU/cm3 for tylosine, 0.03 to 0.5 per cent for ampicillin, and 300 to 2500 IU/cm3 for benzilpenicillin at the rate of 25 cm3/cm2 of a mulberry tree leaf. It was found that chloramphenicol in conc. 0.25 to 0.5 per cent was absorbed in the alimentary canal of the silkworm and was found in the haemolymph in bacteriostatic levels up to the 96th hour following treatment. Tylosine was also absorbed, and in concentrations of 500 to 1500 IU/cm3 was shown to maintain bacteriostatic levels in the haemolymph of the moths for a period of 24-32 hours. Ampicillin and penicillin were absorbed to a slight extent, and were eliminated from the haemolymph up to the eighth hour. It is suggested to use chloramphenicol and tylosine in the concentrations referred to for the control of the spontaneous nuclear polyhedria and flasheria in silkworm moths.

Absorption↗
PubMed1982

[Separation and properties of multiple forms of acid phosphatase from the tissues and organs of the mulberry silkworm].

The multiple forms of acid phosphatase from the hemolymph, fat body, intestinal wall and silk gland of the silkworm larvae differing in their mobility during polyacrylamide gel electrophoresis were separated by isoelectrofocusing, gel filtration and ion-exchange chromatography and characterized in terms of their molecular weight, isoelectric points and substrate specificity. It was found that silkworm tissues contain several enzyme forms possessing broad substrate specificity (EC 3.1.3.2) as well as forms predominantly catalyzing the hydrolysis of glucose-1-phosphate (EC 3.1.3.10). The enzyme forms with a broad substrate specificity were detected in all tissues studied with the exception of hemolymph and were found to have the molecular weights above 60,000, pI greater than pH 6.0 and the highest activity within the pH range of 3.0-4.5. The enzyme forms causing predominant hydrolysis of glucose-1-phosphate detected in the hemolymph, fat body and intestinal wall are characterized by Mr = 30,000-100,000, pI below 6.0 and the highest activity within the pH range of 4.8-5.6. A possible role of the multiple forms of acid phosphatase in silkworm metabolism is discussed.

Acid Phosphatase↗
PubMed1981

[Experiments to inactivate the entomopathogenic action of the preparation dipel in the silkworm Bombyx mori L].

Experiments were carried out at the vivarium of the Silkworm Experimental Station in Vratsa during the autumn silkworm feeding in 1980, using the Kinshu x Showa hybrid. Tested was its tolerance of a water solution of chlorinated lime with active chlorine from 0.003 to 1.0 per cent administered orally with the feed. Studied was at the same time the inactivating capacity of these chlorine solutions with regard to 0.3 per cent water solutions of dipel in less than a minute's time, the latter being sprayed over the leaves of mulberry trees 24 hours prior to giving the leaves to the worms. It was found that the silkworms tolerated well mulberry leaves sprayed with water solution of chlorinated lime of active chlorine ranging from 0.003 up to 0.4 per cent. Rates of 0.06-0.07 per cent active chlorine could inactivate dipel in 0.3 per cent solution. It is believed that aqueous solutions of chlorinated lime of 0.06-0.07 per cent active chlorine could be used in the inactivation of dipel in concentration not higher than 0.3 per cent when the preparation is sprayed at the rate of 100 cm3/m2 in mulberry plantations in the period of growing.

Animals↗
PubMed1995

High-level expression of human beta-interferon gene in the silkworm with new constructed BmNPV vector.

Bombyx mori nuclear polyhedrosis virus (BmNPV) and Bombyx mori cells as well as silkworm larvae were used successfully for the production of biologically active recombinant proteins. There are only a few types of BmNPV general vectors. Here a new type of vector plasmid pBm92 was constructed in this experiment. The translational initiation codon ATG of the polyhedrin gene in Pbm92 was changed into ATT, and then five cloning sites of a foreign gene were ligated after the +12 bp site of the polyhedrin gene. Human beta-interferon (HuIFN-beta) gene was cloned into Pbm92 to construct pBmIFN +12; meanwhile we constructed the transfer vector Pbmifn-3 in which HuIFN-beta was cloned after the -3 bp site of the polyhedrin gene. BM-N cells were cotransfected with the two types of transfer vector plasmid DNAs and BmNPV genomic DNA. Recombinant viruses that were screened did not produce polyhedrin inclusion bodies in the virus plaque assay, and were identified by the hybridization of recombinant virus DNA with HuIFN-b gene probe. IFN activity of the culture media of Bm-N cells infected with recombinant virus BmIFN +12 was 2.0 x 10(6) IU/mL, and IFN activity of hemolymph of silkworm larvae infected with BmIFN +12 was 5.0 x 10(7) IU/mL. Expression level of BmIFN +12 was two to four times more than that of BmIFN -3. The rHuIFN-beta produced by BM-N cells and silkworm larvae has an antigenicity identical to that of the native HuIFN-beta.

Animals↗
PubMed2026

The complete sequence of the silkworm W chromosome uncovers its rapid evolution by large-scale duplications/deletions and translocation of W-linked genes.

The complete sequence of the W chromosome, which carries feminization activity in the silkworm, is crucial for understanding the sex-determination system in Lepidoptera. However, extensive accumulation of transposons due to lack of recombination, the very rare protein-coding genes and almost no information about molecular markers has hindered full W sequencing. We report the first complete silkworm W sequence (T2T_W, 11683305 bp) obtained by combining sequencing-assembly technologies and newly developed error detection methods, evaluated with genetically mapped W-RAPD markers, W-mutants, and W-derived BAC clones. The T2T_W sequence showed that the W is composed of a massive 92% accumulation of transposons and repeat sequences, among which the main constituents are intact LTR/LINE retrotransposons indicating recent expansions. In addition to Fem clusters producing Fem piRNA (Feminizer-derived PIWI-interacting RNA), we found 26 protein-coding genes in the W sequence. These include four gene pairs encoding zinc-finger motifs designated z1:z20 and a gene encoding serine/arginine repetitive matrix protein 1-like (SRRM1-like). To identify candidate genes for female sex-determination and differentiation we also sequenced the shortest W (3.8 Mb) from a translocation mutant with feminizing activity, which harbored four conventional genes: a Fem cluster, a pair of z1:z20 isoforms, z20-S, and a SRRM1-like gene. Phylogenetic analysis revealed that z1:z20 originated from a copy of an autosomal zinc-finger gene pair, z2:z21, translocated onto the W around 2.43 Mya and subsequently amplified to yield 4 W-linked zinc-finger gene pairs. The complete W sequence revealed that large-scale deletions and amplifications played a significant role in W chromosome evolution.

Animals↗
PubMed1998

Sperm-mediated gene transfer in the silkworm Bombyx mori.

Plasmid DNA containing the CAT reporter gene was injected into the testis of V instar silkworm larvae. The persistence, expression, and transmission of the injected DNA were monitored in the injected individuals till eclosion as well as in the progeny. The DNA injected into the testis persisted extrachromosomally during the entire period of metamorphosis and was also transferred into the egg via sperm during fertilization. Injected plasmids were rescued from the moths that emerged from the injected larvae and also from the eggs laid by the moths that copulated with injected males. Positive signals for CAT assay in the experimental samples suggested that the injected DNA was internalized in the testicular cells and sperm. The persistence, expression, and transmission of the DNA injected into the testes indicate that sperm-mediated gene transfer is possible in the silkworm, Bombyx mori.

Animals↗
PubMed2003

Effects of silkworm paralytic peptide on in vitro hematopoiesis and plasmatocyte spreading.

Bombyx mori paralytic peptide (BmPP), a multifunctional cytokine-like molecule, is expressed in the hematopoietic organ-wing imaginal disc complex, suggesting that BmPP is involved in both immune response and the hematopoietic process. We studied the effects of BmPP on plasmatocytes and hematopoietic organs of the silkworm. BmPP (1 microM) stimulated spreading of circulating plasmatocytes, but the percentage of spread plasmatocytes was only 20%. Over 10 nM of BmPP, however, elicited prominent spreading in 70% of young plasmatocytes discharged from cultured hematopoietic organs. Cells in hematopoietic organs that were enzymatically dispersed did not spread even after adding 100 nM of BmPP, indicating that plasmatocytes acquired BmPP-sensitivity immediately after discharge. When cultured in a medium containing larval plasma, hematopoietic organs grew markedly and discharged a large number of hemocytes, over 95% of which were morphologically plasmatocytes. The hemocyte discharge was blocked in the medium containing BmPP dose-dependently, although hematopoietic organ growth was not suppressed. These results suggest that BmPP plays important roles both in hematopoietic regulation and in the hemocyte immune reaction of the silkworm.

Animals↗
PubMed2006

EST-based profiling and comparison of gene expression in the silkworm fat body during metamorphosis.

The fat body plays key roles in metabolism and sustenance of growth throughout the life of a silkworm, and thus represents a model tissue for studying development and metamorphosis. Analysis of 18,480 ESTs derived from larval and pupal fat body cDNA libraries allowed characterization of gene expression patterns in the fat body during metamorphosis. By Phrap assembling, 6,814 estimated transcription units (TUs) were generated, 2,673 of which contained 60% of the total ESTs and represented 1,366 distinctive known genes. These genes were classified into 14 categories based on their known or putative functions, and most were found to be involved in metabolism and cell defense. Further comparative analysis of the expression profiles revealed that the gene expression patterns in the larval fat body strikingly differed from those in the pupal fat body. From this, we identified a subset of genes potentially associated with metamorphic events such as the formation or destruction of specific tissues, and simultaneously confirmed the stage-specific expression patterns of several identified genes using RT-PCR examination. This work will provide a valuable resource for studying regulatory mechanisms associated with fat body developmental changes and silkworm metamorphosis.

Animals↗
PubMed1989

HPLC separation and characterization of chlorin derivatives with intact ring V from acid degradation products of silkworm excrement crude chlorophyll mixture.

A reversed-phase HPLC system with 88% methanol in 1 M ammonium acetate buffer pH 5.35 as the mobile phase on an ODS column was used to analyse pheophorbides a, a', b, b' and pyropheophorbides a and b. Pyropheophorbides a and b were found in samples obtained from silkworm excrement but not from spinach leaves though the preparation methods used were the same. This difference suggests that chlorophylls undergo metabolism in the body of silkworm to give pyrochlorophyll derivatives.

Animals↗
PubMed1995

Reexamination of properties of prophenoloxidase isolated from larval hemolymph of the silkworm Bombyx mori.

Prophenoloxidase in hemolymph of the silkworm (Bombyx mori) was purified by the method of Ashida (Ashida, M. (1971) Arch. Biochem. Biophys. 144, 749-762) with slight modifications to further increase the purity, and its properties were reinvestigated. The purified prophenoloxidase gave two discrete bands in isoelectric focusing-polyacrylamide gel electrophoresis (IEF-PAGE) (pI 4.95 and 4.98) and in native-polyacrylamide gel electrophoresis with 4.5% separating gel. Each band in IEF-PAGE was separated into two bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with mobilities corresponding to 71.5- and 71-kDa polypeptides. In HPLC on octadecyl column the prophenoloxidase preparation gave two well-separated symmetrical peaks (proPO polypeptide I and proPO polypeptide II). The molecular masses of the proPO polypeptides I and II were determined to be 71.5 and 71 kDa in SDS-PAGE and 78,880 and 81,105 Da by matrix-assisted laser desorption ionization mass spectrometry, respectively. Native prophenoloxidase was eluted at a position corresponding to 126-kDa protein in gel permeation chromatography. Amino acid compositions and peptide mappings of proPO polypeptides indicated that both polypeptides differ in their primary structures. These results are discussed in relation to the subunit structure, the presence of bicopper cluster, and the polymorphism of prophenoloxidase in silkworm hemolymph.

Amino Acids↗
PubMed2000

The enzyme that synthesizes tetrahydrobiopterin from 6-pyruvoyl-tetrahydropterin in the lemon mutant silkworm consists of two carbonyl reductases.

Tetrahydrobiopterin plays an important role in the biosynthesis of certain neurotransmitters. Using DEAE-Sepharose FF column chromatography, we separated the enzyme that synthesizes tetrahydrobiopterin from 6-pyruvoyl-tetrahydropterin [which is different from sepiapterin reductase (EC 1.1.1.153)] in the lemon mutant of the silkworm Bombyx mori into two fractions, which were named carbonyl reductase I (CR I) and carbonyl reductase II (CR II). The CR I enzyme converted 6-pyruvoyl-tetrahydropterin to 6-lactoyl-tetrahydropterin, while CR II converted 6-pyruvoyl-tetrahydropterin to 1'-hydroxy-2'-oxopropyl-tetrahydropterin, both reactions occurring only in the presence of NADPH. Neither of the two carbonyl reductases alone was able to catalyze the conversion of 6-pyruvoyl-tetrahydropterin to tetrahydrobiopterin in the presence of NADPH. However, when CR I was mixed with CR II in the reaction mixture, 6-pyruvoyl-tetrahydropterin was reduced to tetrahydrobiopterin in the presence of NADPH. Moreover, CR I catalyzed the formation of tetrahydrobiopterin from 1'-hydroxy-2'-oxopropyl-tetrahydropterin, while CR II converted 6-lactoyl-tetrahydropterin to tetrahydrobiopterin, both reactions occurring only in the presence of NADPH. Our results suggest that there are two potential routes for formation of tetrahydrobiopterin from 6-pyruvoyl-tetrahydropterin in the lemon mutant silkworm. In the first route, 1'-hydroxy-2'-oxopropyl-tetrahydropterin is formed from 6-pyruvoyl-tetrahydropterin by CR II and then reduced to tetrahydrobiopterin by CR I, both reactions occurring only in the presence of NADPH. In the other route, 6-pyruvoyl-tetrahydropterin is reduced to 6-lactoyl-tetrahydropterin by CR I and then converted to tetrahydrobiopterin by CR II, both reactions occurring only in the presence of NADPH.

Alcohol Oxidoreductases↗
PubMed1993

Active conformation of the pyrokinin/PBAN neuropeptide family for pheromone biosynthesis in the silkworm.

Members of the pyrokinin/pheromone biosynthesis activating neuropeptide family elicit pheromonotropic activity in at least two species of moths. We report that in the silkworm (Bombyx mori) the conformationally constrained octapeptide analog cyclo[Asn-Thr-Ser-Phe-Thr-Pro-Arg-Leu] retains 10% of the pheromonotropic activity of naturally occurring Bom-PBAN-I, a 33 amino acid peptide. Previous data from CD, NMR, and molecular dynamics analyses indicate a type I beta-turn conformation for active core residues Thr-Pro-Arg-Leu in the cyclic analog. The rigidity of the well-defined backbone structure of this cyclic pyrokinin/PBAN analog suggests that it represents the conformation necessary to interact with the pheromonotropic receptor site in the silkworm.

Amino Acid Sequence↗
PubMed1999

Prothoracicotropic activity of SBRPs, the insulin-like peptides of the saturniid silkworm Samia cynthia ricini.

Synthesis and secretion of the insect molting hormone ecdysteroid in the prothoracic glands (PGs) are stimulated by the prothoracicotropic hormone (PTTH) secreted by the brain. Bombyxins, insulin-like peptides of the silkworm Bombyx mori, show prothoracicotropic activity when administered to the saturniid silkworm Samia cynthia ricini, but they are inactive to B. mori itself. Recently, the genes for the bombyxin homologs of S. cynthia ricini (referred to as Samia bombyxin-related peptides, SBRPs) were cloned. To examine the prothoracicotropic activity of SBRPs on S. cynthia ricini, we synthesized two representative molecules, SBRP-A1 and -B1. They promoted pupa-to-adult development with ED(50) of 50 and 10 ng/pupa (EC(50) of 5 and 1 nM), respectively.

Amino Acid Sequence↗
PubMed2001

Molecular cloning of Bombyx cerebral opsin (Boceropsin) and cellular localization of its expression in the silkworm brain.

We have cloned a cDNA for a novel opsin from the larval brain of the silkworm Bombyx mori in which the photoperiodic photoreceptor had been supposed to reside in the cephalic central nervous system (CNS). Its deduced amino acid sequence was composed of 381 amino acids and included amino acid residues highly conserved in insect visual pigments. This opsin belonged to the long wavelength photoreceptor group of insect opsins and showed the greatest degree of homology (84%) with the green visual photoreceptor in the sphingid moth. We have designated this Bombyx cerebral opsin as Boceropsin. Southern blotting experiments indicated that the Boceropsin gene is present in a single copy, and RT-PCR analysis revealed that Boceropsin mRNA is expressed in the larval brain but not in the subesophageal ganglion (Sg) or thoracic ganglion (Tg). Immunohistochemical analyses demonstrated that Boceropsin protein is present bilaterally in some defined cells localized in the brain of Bombyx larvae. This is the first report of expression of an opsin-based protein in CNS of an insect. The possibility that the Boceropsin functions as the photoperiodic receptive pigment in the silkworm is also discussed.

Amino Acid Sequence↗
PubMed1994

Intermittent expression of BmFTZ-F1, a member of the nuclear hormone receptor superfamily during development of the silkworm Bombyx mori.

BmFTZ-F1 is a sequence-specific DNA-binding factor in the silkworm Bombyx mori sharing similar biochemical characteristics with Drosophila FTZ-F1, a member of the nuclear hormone receptor superfamily. Using DNA sequence homology with FTZ-F1 and information on tryptic peptide sequences of BmFTZ-F1, we isolated a cDNA encoding for BmFTZ-F1. Amino acid sequences in the zinc finger DNA-binding region and the putative ligand-binding domain of BmFTZ-F1 showed strong similarity to not only FTZ-F1 but also its mammalian homologues, LRH-1, ELP, and Ad4BP, suggesting the importance of each region for the function of these proteins. Northern blot analyses of RNA isolated from the middle and posterior silk glands and fat bodies showed that a 6.1-kb BmFTZ-F1 mRNA is present in all tissues so far examined. Expression of BmFTZ-F1 mRNA is intermittent, being high during larval molting and both the larval-pupal and the pupal-adult transformations. Injection of 20-hydroxyecdysone at the third day of the 5th instar larvae induced BmFTZ-F1 mRNA in the posterior silk gland after 24 hr. When 5th instar silk glands were cultured in vitro, BmFTZ-F1 mRNA was induced by a 6-hr exposure to 20-hydroxyecdysone followed by 6 hr in hormone-free medium. These results suggest that BmFTZ-F1 is inducible by decline in the ecdysteroid titer and may play an important role in the development of the silkworm as a transcription factor.

Amino Acid Sequence↗