Metabolism of saturated 1-14C-labelled fatty acids in the silkworm Bombyx mori L.
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ABSTRACT:
SUBMITTER: Sridhara S
PROVIDER: S-EPMC1264824 | biostudies-other | 1966 Jan
REPOSITORIES: biostudies-other
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Project description:BACKGROUND: The domesticated silkworm, Bombyx mori, is the model insect for the order Lepidoptera, has economically important values, and has gained some representative behavioral characteristics compared to its wild ancestor. The genome of B. mori has been fully sequenced while function analysis of BmChi-h and BmSuc1 genes revealed that horizontal gene transfer (HGT) maybe bestow a clear selective advantage to B. mori. However, the role of HGT in the evolutionary history of B. mori is largely unexplored. In this study, we compare the whole genome of B. mori with those of 382 prokaryotic and eukaryotic species to investigate the potential HGTs. RESULTS: Ten candidate HGT events were defined in B. mori by comprehensive sequence analysis using Maximum Likelihood and Bayesian method combining with EST checking. Phylogenetic analysis of the candidate HGT genes suggested that one HGT was plant-to- B. mori transfer while nine were bacteria-to- B. mori transfer. Furthermore, functional analysis based on expression, coexpression and related literature searching revealed that several HGT candidate genes have added important characters, such as resistance to pathogen, to B. mori. CONCLUSIONS: Results from this study clearly demonstrated that HGTs play an important role in the evolution of B. mori although the number of HGT events in B. mori is in general smaller than those of microbes and other insects. In particular, interdomain HGTs in B. mori may give rise to functional, persistent, and possibly evolutionarily significant new genes.
| S-EPMC3116507 | biostudies-other
Project description:Herein, we performed RNA-seq analysis of ten major tissues/subparts of silkworm larvae. The sequences were mapped onto the reference genome assembly and the reference transcriptome data were successfully constructed. The reference data provided a nearly complete sequence for sericin-1, a major silk gene with a complex structure. We also markedly improved the gene model for other genes. The transcriptomic expression was investigated in each tissue and a number of transcripts were identified that were exclusively expressed in tissues such as the testis. Transcripts strongly expressed in the midgut formed tight genomic clusters, suggesting that they originated from tandem gene duplication. Transcriptional factor genes expressed in specific tissues or the silk gland subparts were also identified. We successfully constructed reference transcriptome data in the silkworm and found that a number of transcripts showed unique expression profiles. These results will facilitate basic studies on the silkworm and accelerate its applications, which will contribute to further advances in lepidopteran and entomological research as well as the practical use of these insects.
| S-EPMC8228281 | biostudies-literature
Project description:Gloverin is one of the glycine-rich antimicrobial peptide exclusively found in Lepidoptera insects. It is generally activated through the innate immune system in insects. In this study, recombinant Gloverin2 from Bombyx mori (BmGlv2) was synthesized using a prokaryotic expression system. Circular dichroism spectroscopy showed that the recombinant BmGlv2 has random coil structure, which is relatively stable at the temperatures ranging from 15 to 82.5 °C. Antimicrobial activity analysis revealed that BmGlv2 significantly inhibited the growth of gram-negative bacteria, Escherichia coli JM109 and Pseudomonas putida, by disrupting cell integrity. Western blotting and immunofluorescence analyses suggested that BmGlv2 absorbed on the cell surface after incubation, which might be the first step in the antibacterial process. Our results also proved that the cell wall component lipopolysaccharides (LPS) induce a conformational change in BmGlv2 from a random coil to ?-helix. Subsequently, ?-helical BmGlv2 would recruit more BmGlv2 and form higher aggregation state. Collectively, these findings expand our understanding of antibacterial mechanism of BmGlv2.
| S-EPMC6121877 | biostudies-literature
Project description:BackgroundIn our previous study, we identified four isoforms of the Bmovo gene, Bmovo-1, Bmovo-2, Bmovo-3 and Bmovo-4 from the silkworm ovary and verified that ovarian development was regulated by the BmOVO proteins.ResultsTo understand the regulatory mechanisms of ovarian development, the regulation of four BmOVO isoforms on the B. mori ovarian tumor (Bmotu) promoter activity was investigated with luciferase reporter assays. The results showed the Bmotu promoter activity was positively regulated by BmOVO-1, BmOVO-2, BmOVO-3 and BmOVO-4 in a dose-dependent manner, of which BmOVO-2 had the highest transcriptional activation. However, the first (A1) and third acidic domains (A3) at the N-terminus of BmOVO-1 are transcriptional repression domains, while the fourth (A4) and fifth acidic domains (A5) are transcriptional activation domains. A recombinant BmOVO zinc-finger domain was found to bind to the GTACCGTTGTA sequence located at the Bmotu promoter. Furthermore, the Bmotu promoter activity was negatively regulated by 'Tal-like' peptide, which can trigger BmOVO-1 degradation at the N-terminus.ConclusionsThese results will help us to further understand the regulatory mechanisms of BmOVO isoforms on Bmotu promoter activity and ovarian development in the silkworm.
| S-EPMC6503385 | biostudies-literature
Project description:To investigate the patterns of nucleotide diversity in domesticated silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) and its wild relative, Chinese wild silkworm, Bombyx mandarina Moore, we sequenced nine nuclear genes. Neutrality test and coalescent simulation for these genes were performed to look at bottleneck intensity and selection signature; linkage disequilibrium (LD) within and between loci was employed to investigate allele association. As a result, B. mori lost 33-49% of nucleotide diversity relative to wild silkworm, which is similar to the loss levels found in major cultivated crops. Diversity of B. mori is significantly lower than that of B. mandarina measured as ?(total) (0.01166 vs. 0.1741) or ?(W)(0.01124 vs. 0.02206). Bottleneck intensity of domesticated silkworm is 1.5 (in terms of k = N(b) /d, N(b) -bottleneck population size; d-bottleneck duration) with different durations. Gene DefA showed signature of artificial selection by all analysis methods and might experience strong artificial selection in B. mori during domestication. For nine loci, both curves of LD decay rapidly within 200 bp and drop slowly when distance is > 200 bp, although that of B. mori decays slower than B. mandarina at loci investigated. However, LD could not be estimated at DefA in B. mori and at ER in both silkworms. Elevated LD observed in B. mori may be indicator of selection and demographic events.
| S-EPMC3391917 | biostudies-literature
Project description:1. After the injection of sodium [1-(14)C]acetate, the highest incorporation of (14)C into the lipids of the silkworm was observed after 24hr. 2. The specific radioactivity of the palmitic acid fraction was greater and increased more rapidly than that of the stearic acid fraction, which was consistent with the precursor-product relationship to be expected on the basis of current concepts of fatty acid synthesis in vivo. 3. The results indicate the probability of synthesis of lipid components in tissues other than the fat body. 4. Fractionation studies indicate considerable differences in the rate of incorporation of [1-(14)C]acetate into neutral lipids and phospholipids between larvae and pupae as well as among tissues of larvae. 5. The rate of incorporation of [1-(14)C]acetate remains constant throughout pupal development.
| S-EPMC1206605 | biostudies-other
Project description:BACKGROUND: Insect cuticle plays essential roles in many physiological functions. During molting and metamorphosis tremendous changes occur in silkworm cuticle where multiple proteins exist and genes encoding them constitute about 1.5% of all Bombyx mori genes. RESULTS: In an effort to determine their expression profiles, a microarray-based investigation was carried out using mRNA collected from larvae to pupae. The results showed that a total of 6676 genes involved in various functions and physiological pathways were activated. The vast majority (93%) of cuticular protein genes were expressed in selected stages with varying expression patterns. There was no correlation between expression patterns and the presence of conserved motifs. Twenty-six RR genes distributed in chromosome 22 were co-expressed at the larval and wandering stages. The 2 kb upstream regions of these genes were further analyzed and three putative elements were identified. CONCLUSIONS: Data from the present study provide, for the first time, a comprehensive expression profile of genes in silkworm epidermal tissues and evidence that putative elements exist to allow massive production of mRNAs from specific cuticular protein genes.
| S-EPMC2848646 | biostudies-literature
Project description:Bombyx mori densovirus 1 (BmDNV-1), a major pathogen of silkworms, causes significant losses to the silk industry. The structure of the recombinant BmDNV-1 virus-like particle has been determined at 3.1-Å resolution using X-ray crystallography. It is the first near-atomic-resolution structure of a virus-like particle within the genus Iteravirus. The particles consist of 60 copies of the 55-kDa VP3 coat protein. The capsid protein has a ?-barrel "jelly roll" fold similar to that found in many diverse icosahedral viruses, including archaeal, bacterial, plant, and animal viruses, as well as other parvoviruses. Most of the surface loops have little structural resemblance to other known parvovirus capsid proteins. In contrast to vertebrate parvoviruses, the N-terminal ?-strand of BmDNV-1 VP3 is positioned relative to the neighboring 2-fold related subunit in a "domain-swapped" conformation, similar to findings for other invertebrate parvoviruses, suggesting domain swapping is an evolutionarily conserved structural feature of the Densovirinae.
| S-EPMC3126189 | biostudies-literature
Project description:Insect cuticle plays essential roles in multiple physiological functions. During molting and metamorphosis, tremendous changes occur in silkworm cuticles. Silkworm is a model of Lepidoptera insects; however, little is known about the stage expression profiles of genes in cuticles of silkworm. In the present study, we selected 16 developmental stages, ranging from day 1 of the first instar larvae to day 8 of pupae, to perform microarray-based expression profiles. The data told us that various functions and physiological pathways were activated in the cuticle. Moreover, the expression profiles of cuticular protein genes, as the important components of cuticle, were investigated. The current study provides important insights for the functional study of insect cuticle and the regulation of insect cuticular protein genes.
2009-11-05 | GSE18878 | GEO
Project description:The conditions required for the emergence of supercontraction in regenerated silkworm (Bombyx mori) silk fibers are assessed through an experimental approach that combines the spinning of regenerated fibers with controlled properties and their characterization by 13C solid-state nuclear magnetic resonance (NMR). Both supercontracting and non-supercontracting regenerated fibers are produced using the straining flow spinning (SFS) technique from 13C labeled cocoons. The short-range microstructure of the fibers is assessed through 13C CP/MAS in air and 13C DD/MAS in water, and the main microstructural features are identified and quantified. The mechanical properties of the regenerated fibers and their microstructures are compared with those of natural silkworm silk. The combined analysis highlights two possible key elements as responsible for the emergence of supercontraction: (1) the existence of an upper and a lower limit of the amorphous phase compatible with supercontraction, and (2) the existence of two ordered phases, β-sheet A and B, which correspond to different packing arrangements of the protein chains.
| S-EPMC6382804 | biostudies-other