1,720,988 research outputs found
An Efficient Workflow for Screening and Stabilizing CRISPR/Cas9-Mediated Mutant Lines in Bombyx mori
Full text linkThe domestic silkworm Bombyx mori is extensively studied as a model organism for lepidopteran genetics and has an economic value in silk production. Silkworms also have applications in biomedical and cosmetic industries, and the production of mutant B. mori strains significantly enhances basic and applied silkworm research. In recent years, CRISPR/Cas9 technology is being rapidly adopted as the most efficient molecular tool for generating silkworm lines carrying mutations in target genes. Here we illustrate a complete and efficient workflow to screen, characterize rapidly and follow mutations through generations, allowing the generation of B. mori lines, stably inheriting single CRISPR/Cas9-induced mutations. This approach relies on the use of different molecular methods, the heteroduplex assay, cloning followed by Sanger sequencing, and the amplification refractory mutation system PCR. The use of these methodologies in a sequential combination allows the identification of CRISPR/Cas9-induced mutations in genes mapping on both autosomes and sex chromosomes, and the selection of appropriate individuals to found stable mutant B. mori lines. This protocol could be further applied to screen CRISPR/Cas9 mutations in haploid insects
Silkworm and Silk: Traditional and Innovative Applications
Full text linkThe various subjects covered in the present Special Issue “Silkworm and Silk: Traditional and Innovative Applications” demonstrate how sericulture, a practice deeply rooted in human history, can act as a bridge to bring together an exceptionally wide range of scientific and technical expertise in both conventional topics and cutting-edge technologies [...
Bombyx mori from a food safety perspective: A systematic review
No full text: Bombyx mori (BM) is an economically important insect for silk production, and it is also farmed and used as food in different countries around the world. The present systematic review aims to assess the suitability of BM as an edible insect, retrieving data from scientific papers reporting microbiological, chemical, and allergenic hazards of silkworm consumed as either whole insects or insect derivatives. We considered all studies published in peer-reviewed journals in English, French, and Spanish languages. No time limits were imposed. We searched PUBMED, WEB of Science Core Collection, and EMBASE databases. The last literature search was carried out on May 5th, 2021. Data were collected in pre-defined tabular forms for the aforementioned hazards. In total, 65 records investigating the safety aspects were included after screening: 32 on microbiological hazards; 27 on chemical hazards; 16 on allergenic hazards. Concerning microbiological aspects, a high presence of Enterococcus in raw insects (5.00 % to 70.10 %) was reported through metagenomic analysis. Through non-metagenomic methods (classical and biomolecular microbiology techniques), Bacillus cereus and Pseudomonas fluorescens were the most commonly investigated and detected bacteria in the unprocessed insects, while B. cereus and Enterobacteriaceae were studied and reported in insect-based food. The foodborne pathogens Listeria monocytogenes and Salmonella spp. were never detected. Concerning toxicological aspects, three studies assessed the toxicity of BM powder in laboratory animals, but no negative effects were observed. Regarding heavy metal bioaccumulation in BM, evidence was reported for As, Cu, and, Zn. Allergic reactions following the ingestion of BM or derivative products are due to proteins that are widespread in arthropods. Furthermore, BM proteins can undergo possible cross-reactions with proteins of other insect species or crustaceans. However, heat treatments do not seem to reduce the allergenic potential of the silkworm proteins. The major limitation of the present review is that we could include only scientific literature published in Western languages, while the majority of relevant studies were conducted in Asian countries and part of them are published in Asian languages. In conclusion, scientific evidence regarding microbiological and chemical hazards of BM relevant for food safety is very limited. In the present work microbiological and chemical hazards relevant for food safety were identified in BM, however their presence do not impair the use as food but suggest the need for a risk assessment under specific conditions of production and use. Allergic reactions are possible in sensitive individuals following the ingestion of edible BM
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Timing of autophagy and apoptosis during posterior silk gland degeneration in Bombyx mori
No full textOver the years, the silkworm, Bombyx mori, has been manipulated by means of chemical and genetic approaches to improve silk production both quantitatively and qualitatively. The silk is produced by the silk gland, which degenerates quickly once the larva has finished spinning the cocoon. Thus, interfering with this degeneration process could help develop new technologies aimed at ameliorating silk yield. To this end, in this work we studied the cell death processes that lead to the demise of the posterior silk gland of B. mori, directing in particular our attention to autophagy and apoptosis. We focused on this portion of the gland because it produces fibroin, the main component of the silk thread. By using multiple markers, we provide a morphological, biochemical and molecular characterization of the apoptotic and autophagic processes and define their timing in this biological setting. Our data demonstrate that the activation of both autophagy and apoptosis is preceded by a transcriptional rise in key regulatory genes. Moreover, while autophagy is maintained active for several days and progressively digests silk gland cells, apoptosis is only switched on at a very late stage of silk gland demise
An artificial diet for rearing three exotic longhorn beetles invasive to Europe
Full text linkAnoplophora glabripennis, Anoplophora chinensis and Psacothea hilaris hilaris are three invasive exotic longhorn species (Coleoptera Cerambycidae) threatening native broadleaf trees in Europe and North America. Field studies on invasive species are somewhat difficult in the areas of introduction due to the application of eradication measures and the activation of quarantine protocols. Rearing these species in standard laboratory conditions would allow specific ecological and biological investigations to be conducted. In this paper, the rearing of these longhorn beetles has been tested on an artificial diet in laboratory conditions. The tested diet can be used to obtain viable healthy adults of each of the three studied species. P. h. hilaris had the best rearing performance with 74% of eggs producing new adults, while A. chinensis and A. glabripennis were poorer with 24.7% and 23.3%, respectively. The low percentage of emerging A. glabripennis and A. chinensis adults was due mainly to a high mortality of their first instar larvae not entering the diet. Moreover, A. chinensis and A. glabripennis had a mean development time, 60.06 and 37.29 weeks, respectively (including the chilling periods required for pupation), longer than P. h. hilaris (16.1 weeks). During development, larval moults varied according to species and within species ranging from 5-7 (P. h. hilaris), 6-11 (A. chinensis) and 7-8 (A. glabripennis) moults, respectively. Adults of A. glabripennis and P. h. hilaris reared on the diet were bigger than wild specimens collected from the same population, whereas A. chinensis adults were smaller. Adult survival was shorter in A. glabripennis (62.9 days) than in P. h. hilaris (119.3 days). According to the different performance of the three species, the rearing costs were about 2.0, 8.1 and 16.1 US dollars per adult beetle for P. h. hilaris, A. glabripennis and A. chinensis, respectively. A laboratory insect population has to be cost effective and self-sustainable over time, and the tested diet provided valuable results for the low-cost mass rearing of these invasive longhorn beetles
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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