Thirty-five SSR markers were used to construct 96 silkworm races fingerprint. All the SSR markers were polymorphic and unambiguously separated silkworm strains from each other. A total of 467 alleles were detected wit...Thirty-five SSR markers were used to construct 96 silkworm races fingerprint. All the SSR markers were polymorphic and unambiguously separated silkworm strains from each other. A total of 467 alleles were detected with a mean value of 13.34 alleles/locus （range 3-28）. The mean polymorphism index content （PIC） was 0.71 （range 0.299-0.919）. UPGMA cluster analysis of Nei＇s genetic distance grouped silkworm strains on the basis of their origin. The results indicated that SSR markers are efficient tools for fingerprinting cultivars and conducting genetic diversity studies in the silkworm.展开更多
Beyond the production of silk thread, there are several studies showing that the silk is a great biomaterial for surgical sutures and grafts. This paper shows a new technique to produce silk thread changing the natura...Beyond the production of silk thread, there are several studies showing that the silk is a great biomaterial for surgical sutures and grafts. This paper shows a new technique to produce silk thread changing the natural cycle of silk production, which is the production of cocoons. This new method has the purpose of producing a silk fabric free of impurities, through flat surfaces. Six different surfaces were tested: Glass, Formica Surface, Steel and Zinc Sheets, Cotton tissue and Burlap Bag. The first five surfaces had not presented enough larvae alive for statistical analysis, because there were several damages in silkworms larvae that resulted in mortality and low silk production. On the other hand, the burlap bag surface presented good results for web construction by biospinning and its use was indicated for silk industry focused on biomaterials. The present study suggested the potential of naturally biospun web, using Bombyx mori, to develop a new technique to produce silk thread matrices that will have several applications at the industry and production of biomedical materials.展开更多
The fibroin gene expression pattern and regulation of the posterior silkgland were studied by means of expressed sequence tags (ESTs) using the first and fifth day larvae of the fifth instar of silkworm, Bombyx mori L...The fibroin gene expression pattern and regulation of the posterior silkgland were studied by means of expressed sequence tags (ESTs) using the first and fifth day larvae of the fifth instar of silkworm, Bombyx mori L (strain: C 108). The results showed that there were 911 repetitive ESTs and 1950 single sequences (Singlets) among total 2861 consentient sequences, which were spliced. 1335 sequences were identified and the other 1526 were unknown. 5560 sequences (55.89%) in the posterior silkgland cell of the silkworm were new ESTs without homology with EST data published by Mita et al. The number of repetitive ESTs and single sequences from the first day larvae of the fifth instar was double more than that of the fifth day of the same instar in the silkworms. The unigenes which were more than 50 in repetitive EST size (contig size) came to only about 0.5% in total consentient sequences. There were significant differences between gene expression frequencies, and expressed genes were related to fibroin synthesis and its secretion and fibroin composition. Comparing the fifth day with the first day of the fifth instar, the genes-expressed quantity of fibroin heavy-chain gene was 18 fold higher, fibroin light-chain gene 9 fold and fibroin P52 gene 8 fold. 508 genes functioned for cellular component and 315 for enzyme after function tracing. These results implied that the gene expression of the first day was mainly for preparation for fibroin synthesis except for the growth of silkgland cells, and the gene expression of the fifth day of the fifth instar was mainly for synthesizing and excreting fibroin. Because the ratio of heavy chain, light chain and p25 of fibroin was not 6:6:1 as theoretically expected, or its special H-chain structure, the H-chain gene was not easy to detect through EST technique. Most of genes among total 2861 consentient sequences functioned for fibroin synthesis and secretion. This suggested the fibroin synthesis and secretion procedure of the posterior silkgland was more complex than the knowledge we have.展开更多
One of the major diseases in sericulture is the mid gut polyhedrosis, in which the pathogen is the cytoplasmic polyhedrosis virus （CPV）. After the silkworm larvae had been fed or injected with Poly Ⅰ: C or 2′, 5′...One of the major diseases in sericulture is the mid gut polyhedrosis, in which the pathogen is the cytoplasmic polyhedrosis virus （CPV）. After the silkworm larvae had been fed or injected with Poly Ⅰ: C or 2′, 5′-oligo （A） （2′, 5′-P3A3）, silkworms increased their ability to inhibit CPV, eventually, the attack rate of the silkworm decreased by about 40—50％. Moreover, it was found that Poly Ⅰ: C was able to induce some new proteins which seemed to be connected with the antiviral activity of the silkworm larva.展开更多
文摘Thirty-five SSR markers were used to construct 96 silkworm races fingerprint. All the SSR markers were polymorphic and unambiguously separated silkworm strains from each other. A total of 467 alleles were detected with a mean value of 13.34 alleles/locus （range 3-28）. The mean polymorphism index content （PIC） was 0.71 （range 0.299-0.919）. UPGMA cluster analysis of Nei＇s genetic distance grouped silkworm strains on the basis of their origin. The results indicated that SSR markers are efficient tools for fingerprinting cultivars and conducting genetic diversity studies in the silkworm.
文摘Beyond the production of silk thread, there are several studies showing that the silk is a great biomaterial for surgical sutures and grafts. This paper shows a new technique to produce silk thread changing the natural cycle of silk production, which is the production of cocoons. This new method has the purpose of producing a silk fabric free of impurities, through flat surfaces. Six different surfaces were tested: Glass, Formica Surface, Steel and Zinc Sheets, Cotton tissue and Burlap Bag. The first five surfaces had not presented enough larvae alive for statistical analysis, because there were several damages in silkworms larvae that resulted in mortality and low silk production. On the other hand, the burlap bag surface presented good results for web construction by biospinning and its use was indicated for silk industry focused on biomaterials. The present study suggested the potential of naturally biospun web, using Bombyx mori, to develop a new technique to produce silk thread matrices that will have several applications at the industry and production of biomedical materials.
文摘The fibroin gene expression pattern and regulation of the posterior silkgland were studied by means of expressed sequence tags (ESTs) using the first and fifth day larvae of the fifth instar of silkworm, Bombyx mori L (strain: C 108). The results showed that there were 911 repetitive ESTs and 1950 single sequences (Singlets) among total 2861 consentient sequences, which were spliced. 1335 sequences were identified and the other 1526 were unknown. 5560 sequences (55.89%) in the posterior silkgland cell of the silkworm were new ESTs without homology with EST data published by Mita et al. The number of repetitive ESTs and single sequences from the first day larvae of the fifth instar was double more than that of the fifth day of the same instar in the silkworms. The unigenes which were more than 50 in repetitive EST size (contig size) came to only about 0.5% in total consentient sequences. There were significant differences between gene expression frequencies, and expressed genes were related to fibroin synthesis and its secretion and fibroin composition. Comparing the fifth day with the first day of the fifth instar, the genes-expressed quantity of fibroin heavy-chain gene was 18 fold higher, fibroin light-chain gene 9 fold and fibroin P52 gene 8 fold. 508 genes functioned for cellular component and 315 for enzyme after function tracing. These results implied that the gene expression of the first day was mainly for preparation for fibroin synthesis except for the growth of silkgland cells, and the gene expression of the fifth day of the fifth instar was mainly for synthesizing and excreting fibroin. Because the ratio of heavy chain, light chain and p25 of fibroin was not 6:6:1 as theoretically expected, or its special H-chain structure, the H-chain gene was not easy to detect through EST technique. Most of genes among total 2861 consentient sequences functioned for fibroin synthesis and secretion. This suggested the fibroin synthesis and secretion procedure of the posterior silkgland was more complex than the knowledge we have.
文摘One of the major diseases in sericulture is the mid gut polyhedrosis, in which the pathogen is the cytoplasmic polyhedrosis virus （CPV）. After the silkworm larvae had been fed or injected with Poly Ⅰ: C or 2′, 5′-oligo （A） （2′, 5′-P3A3）, silkworms increased their ability to inhibit CPV, eventually, the attack rate of the silkworm decreased by about 40—50％. Moreover, it was found that Poly Ⅰ: C was able to induce some new proteins which seemed to be connected with the antiviral activity of the silkworm larva.
