1,720,958 research outputs found
Linseed to increase n-3 fatty acids in Tenebrio molitor (Coleoptera Tenebrionidae)
Full text linkThe yellow mealworm Tenebrio molitor is one of the most promising edible insect species for human consumption and its potential use as a supplement of unsaturated fatty acids (UFA) for human diet, has been recently confirmed. The possibility to enhance polyunsaturated acids (PUFA), especially omega-3 (n-3) content, was evaluated in T. molitor mealworms. The purpose was to obtain an n-6/n-3 ratio more suitable for human consumption, which is useful for the secondary prevention of cardiovascular diseases. To this end, tests were carried out by adding linseed, as source of n-3 acid, to insect feeding diets. A decrease of saturated fatty acids (SFA) and an increase of PUFA contents, especially n-3 acid, was simultaneously observed in larvae fed on almost all the diets enriched with linseed. As a result, supplementation of feeding diets with linseed determined a favorable insect growth rate and a decrease of n-6/n-3 ratio to values more suitable for the prevention and treatment of cardiovascular diseases
Chemical evaluation of the Rhynchophorus ferrugineus larvae fed on different substrates as human food source
No full textWe investigated the chemical composition of the weevil Rhynchophorus ferrugineus larvae, traditionally used as human food in Asia and known worldwide as one of the most significant pest for palm trees. Total fat content and fatty acid composition were analyzed using standard methodologies in (1) weevil larvae reared on apple fruit slices and wild specimens collected from attacked (2) Phoenix canariensis and (3) Syagrus romanzoffiana palm trees. Total fat content was extremely high in all the specimens (ranged between 57.62 and 60.03% based on dry weight). Despite sharing the same prevalent fatty acids (myristic acid, palmitic acid, stearic acid, palmitoleic acid, oleic acid, α-linoleic acid, and α-linolenic acid), fatty acid composition of the wild weevil larvae significantly differed from that of the specimens raised on apple fruit, due to the presence of other minor compounds. In general, a good balance between unsaturated fatty acids (∼53.68% of total fatty acids) and saturated fatty acids (∼43.41% of total fatty acids) and a low cholesterol content (74.61-152.32 mg/kg based on dry matter) were detected in all the specimens. Conversely, the weevil larvae did not represent a good source of α-tocopherol (14.17-26.22 mg/kg based on dry matter). The ability of the protein extracts obtained from the weevil larvae to inhibit in vitro the angiotensin-converting enzyme, the main enzyme involved in blood pressure regulation, was also investigated. To simulate gastrointestinal digestion process, protein extracts were hydrolyzed by the gastrointestinal enzymes. A significantly lower IC50 (0.588-0.623 mg/ml) was measured in all the protein extracts after enzymatic hydrolysis versus the corresponding crude protein extracts (3.270-3.752 mg/ml). Given that the weevil larvae are able to provide interesting benefits for human health, this study supports their use as human food not just in the native countries where they are traditionally consumed and farmed but also throughout the world
Cuticle-degrading protease and toxins as virulence markers of Beauveria bassiana (Balsamo) Vuillemin
No full textBeauveria bassiana is one of the most known entomopathogenic fungal species and its
entomopathogenic mechanism involves several bioactive metabolites, mainly cuticle-degrading
enzymes and toxic molecules, which are predicted to play a key role as virulence factors. In this
study six Beauveria bassiana strains (B 13/I03, B 13/I11, B 13/I49, B 13/I57, B 13/I63, and B 13/I64)
were assayed against Tenebrio molitor larvae. Enzymatic activity of total proteases and specifically
Pr 1 and Pr 2, as well as the production of toxic compounds were investigated in each fungal
strain. Toxins were detected both in vitro—in medium filtrates and mycelia—and in vivo—in
Tenebrio molitor larvae infected by the fungal strains tested. B 13/I11 and B 13/I63 strains showed
the most significant entomopathogenic activity against Tenebrio molitor larvae (cumulative
mortality rate 100 and 97%, respectively; average survival time 5.85 and 6.74 days, respectively).
A widely variable and fungal strain-dependent enzymatic activity of total proteases, Pr 1 and Pr 2
was found. Beauvericin, beauvericin A and bassianolide resulted the most prevalent toxins
detected in the substrates analyzed. It has been found that an increase of beauvericin content in
vivo resulted significantly correlated to a decrease of Tenebrio molitor larvae average survival time
in entomopathogenic bioassay (inverse correlation). The involvement of beauvericin in B. bassiana
entomopathogenic process is confirmed; in vitro analysis of cuticle degrading proteases activity
and toxins production in relation to the methods adopted resulted insufficient for a rapid
screening to determine the virulence of B. bassiana strains against Tenebrio molitor larvae
Dietary fatty acids influence the growth and fatty acid composition of the yellow mealworm Tenebrio molitor (Coleoptera: Tenebrionidae)
No full textFat is the second most abundant component of the nutrient composition of the mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) that represents also an interesting source of PUFA, especially n-6 and n-3 fatty acids, involved in prevention of cardiovascular diseases. This study investigated the possibility of modifying the fat content and the FA composition of yellow mealworms through feeding and how this would be influenced by developmental stages, pupal sex, and generation with the future aim of applying this coleopteran as a diet supplement for human health. Growth rate and cumulative mortality percentage on the different feeding substrates were also evaluated to select the optimal conditions for a mass-raising of this insect species. Despite the different fat content in the six different breeding substrates used, T. molitor larvae and pupae contained a constant fat percentage (>34% in larvae and >30% in pupae). A similar total fat content was found comparing larvae and male and female pupae of the second generation to those of the first generation. On the contrary, FA composition differed both in larvae and pupae reared on the different feeding substrates. However, the exemplars reared on the diets based on 100% bread and 100% oat flour showed SFA, PUFA percentages, and an n-6/n-3 ratio more suitable for human consumption; the diet based on beer yeast, wheat flour, and oat flour resulted in a contemporary diet that most satisfied the balance between a fat composition of high quality and favorable growth conditions
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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