1,720,977 research outputs found
Antimicrobial activity of active substance against free-living Erwinia species phylogenetically closer to Candidatus Erwinia dacicola, obligate endosymbiont of Bactrocera oleae
No full textCandidatus Erwinia dacicola is the main symbiotic bacterium of the olive fly, Bactrocera oleae (Diptera: Tephritidae), and it is essential for its suitability. The interruption of this symbiosis is a promising strategy to promote the sustainable control of the olive pest, which causes important economic losses in the Mediterranean basin countries. Since Ca. E. dacicola is uncultivated and cannot be used for in vitro inhibition tests, we evaluated the Minimum Inhibitory Concentration (MIC) of 8 active ingredients against two strains of E. persicina (1LMG 11254T and 2LMG 25707), the phylogenetically closest species to Ca. E. dacicola. The tested compounds were chosen among substances currently allowed in olive cultivation such as fungicides (copper oxychloride-Neoram WG®, dodine-Syllit 544 SC®, mancozeb-Aspor WDG, pyraclostrobin-Cabrio Olivo®, difeconazole-Score 250 EC®-), elicitors (propolis-Serbios®) and fertilizer (copper and citric acid biocomplex -Dentamet® and olive mill wastewater). For each substance, different concentrations (including the field one) were assessed in 96-well microplates, with three replicates for each strain. Subsequently, the concentration that inhibited the growth of the bacteria, were tested on agar plates to confirm the effectiveness. Overall, both strains of E. persicina showed similar MIC values for all compounds, except for propolis. Copper oxychloride (1,50 mg/mL), dodine (0,10 mg/mL), mancozeb (1,60 mg/mL), copper and citric acid biocomplex (3,42 mg/mL) showed their efficacy against E. persicina strains at lower MICs than the field rate; conversely, MICs were higher than the field rate for propolis (146,56 mg/mL and 293,12 mg/mL), pyraclostrobin (8,00 mg/mL) and difeconazole (4,32 mg/mL). Oil mill wastewater had antimicrobial activity at 2,64 mg/mL probably due to the high polyphenols content. These results suggest that these substances could be used in laboratory and field trials, with Ca. E. dacicola as a target, to confirm that E. persicina is suitable as a model for the uncultivated symbiont of B. oleae
The status of the species Lactobacillus rogosae Holdeman and Moore, 1974. Request for an Opinion.
No full textA brief history of the species Lactobacillus rogosae is presented. It was ascertained that the type strain and other existing strains are not available in any established culture collection; therefore, they cannot be included in any scientific study. This matter is referred to the Judicial Commission, asking for an Opinion on the status of the species
Unculturable taxa of insect pests microbiomes: a focus on genera Erwinia, Pantoea and Blattabacterium
No full textConsistent data from different databases are necessary to avoid loss of information about the real microbial biodiversity. The 16S rRNA gene has low discriminatory power and interrelationships in Erwiniaceae members. Therefore, alternative genes must be used. Appropriate use of the status «Candidatus» is advocated for any taxon lacking a pure culture (i.e. B. cuenoti should be indicated as Ca. B. cuenoti). This study provides a robust basis for comparative genomic analyses, aimed at understanding the genomic background related to the free-living state for Ca. E. dacicola
Genomic Characterisation of Starter Cultures and Probiotic Bacteria
No full textThe first publicly available genome sequence of a lactic acid bacteria (LAB) strain commonly used as a starter in dairy fermentations is that of Lactococcus lactis subsp. lactis IL1403 (Bolotin et al., 2001). Since then, a huge number of genome sequences of starter and probiotic LAB has been determined. Indeed, genome sequencing has become the starting point of most microbial studies, since it can provide, at a reasonable cost, the framework of the biology of any strain of interest. Comparative genome analyses can provide insights on the genetic make-up, and thus the metabolic potential, of the strains, as well as on many aspects of their genome evolution and divergence. Further, sequencing of genomes can reveal horizontal gene transfer (HGT) events between species and strains of starter and probiotic cultures. Knowledge of the complete genome sequence is not only useful in discovering novel genes and new properties, but also in determining the absence at the genetic level of undesirable traits. In addition, it is of much help in characterizing the variants of modified/improved strains for both cultures with a technological role, i.e., necessary/useful for food fermentation processes, and a functional role, i.e., able to confer health benefits to the consumer/host (FAO/WHO, 2001; Hill et al., 2014). Genome sequencing can further allow precise identification down to the strain level, while providing strategies for its specific detection and quantification, important aspects for commercially-relevant bacteria
Description of lactic acid bacteria associated with wheat (Triticum durum) and non-conventional flours: focus on their bacteriocinogenic activity
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Identification and functional characterization of Lactobacillus strains isolated from milk and Gioddu, a traditional Sardinian fermented milk
No full textRaw milk from Sardinian cows and sheep, and sheep's milk yoghurt (Gioddu), are food products that are poorly characterized in terms of the presence of mesophilic Lactobacillusstrains, and may be good sources from which to isolate novel bacterial strains. Sixteen Lactobacillusstrains were identified by genotypic and phenotypic methods from samples of sheep's milk (n=7), fermented sheep's milk (n=7) and one sample of cows’ milk. These strains were further characterized for the presence of functional traits useful for probiotic applications, such as resistance to simulated gastric acid, resistance to bile salts, and adhesion of two different cell lines (Caco-2 and MIM/PPK). Moreover, selected aspects correlated with safety (antimicrobial susceptibility and presence of plasmids) and ecological roles (ability to produce biofilms and bacteriocin-like substances) were tested. All but 1 of the 16 strains were unambiguously allotted to three species, L. paracasei (5 strains), L. plantarum (8 strains), and L. reuteri (2 strains). Many of the strains exhibited characteristics suggesting that they would survive in the gastrointestinal tract and also had the capability to attach to various cells. Greater variability was observed for the other traits analyzed. These data suggest that Sardinian artisan dairy products are interesting sources for the isolation of bacterial strains with characteristic and differentiated functional traits
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