1,720,963 research outputs found
How to develop a biofungicide based on a bacterial strain: the main steps for turning your discover into a plant protection product
No full textLess than 0.1 % of the potentially bioactive microbial biocontrol agents reaches the market (estimation based on the number of active strains reported in scientific journals, ‘grey literature’ and theses available on web and the number of registered commercial products). In the last decade research efforts on microbial biocontrol increased dramatically in EU, US and Canada, but also in India, China, Africa, Central and South America. However the EU market returns a very gloomy picture with very few commercial products available for the growers, all based on ‘old’ active ingredients (some of these strains have been identified 30 years ago or even more). The ‘new entries’ are mostly new strains of the same well-known species. To explain such situation we commonly refer to the intrinsic limiting factors in their use (i.e. microbial pesticides are expected to be less effective and more inconsistent than chemicals, they need specific environmental conditions for the application, high technical skills by growers and frequent crop monitoring, etc.) or in the economics (i.e. they are more expensive than chemicals, registration costs are too high for the companies, the market is too narrow to justify investments, etc.). However most of the product development fails for other reasons: as mistakes in the selection of the right strain (both in term of technological properties and level of efficacy) or the target disease and crop (type of disease, market size, etc.), in the IP protection and in the choice of the industrial partner to scale-up the production. This ‘how to’ presentation will define some of the most important steps in the development of a bacterial biofungicide starting from the very beginning and highlights some of the most commons mistakes that prevents these products reaching the market
Study of the genome of Bacillus amyloliquefaciens subsp. plantarum and role of its plasmid (pS499) in rhizosphere interactions
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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
Study of the genome of Bacillus amyloliquefaciens subsp. plantarum S499 and role of its plasmid (pS499) in rhizosphere interactions
Full text linkUnderstanding how soil-borne microorganisms can modulate the plant defence
responses and which factors affect rhizosphere multitrophic interactions is crucial
to improve the efficacy of biopesticides in agriculture. From this perspective,
whole-genome sequencing is a powerful tool to characterize the bacterial strains of
agronomic interest. Among these, Bacillus amyloliquefaciens subsp. plantarum
strain S499 is a plant-beneficial rhizobacterium that shows direct antagonistic
properties against phytopathogenic fungi and, in addition, a remarkable efficacy as
elicitor of induced systemic resistance (ISR) in plants. In these activities, the
production of bioactive secondary metabolites, such as cyclic lipopeptides
belonging to the fengycin, iturin and surfactin families, is involved.
By sequencing, assembling and annotating S499 genome, we identified the
principal genes involved in root colonization, plant-growth promotion and
biocontrol activities. These genes share a high percentage of nucleotide identity
with their homologs in the strain FZB42, the type strain of the bacterial subspecies.
One of the main genetic elements distinguishing S499 from FZB42 is the presence
of extrachromosomal DNA (plasmid pS499). This small rolling circle plasmid was
unknown before S499 genome sequencing, which also allowed to identify on pS499
the genes encoding a Rap-Phr regulatory system involved in quorum sensing.
Through a plasmid-curing approach, we carried out a functional characterization of
pS499. First, we studied the impact of the plasmid loss on the bacterial physiology,
by comparing the behaviours of S499, its plasmid-cured derivative, S499 P-, and
FZB42 on Luria-Bertani (LB) medium. Growth rate, extracellular proteolytic
activity and the regulation of lipopeptide production were significantly affected in
S499 P-. In agreement with an increased release of surfactins, swarming motility
improved after curing, whereas biofilm production was reduced in vitro. When the
evolution of bacterial populations was compared in planta, pS499 seemed not to
influence the root colonization ability, although we observed an over-production of
surfactins by S499 Palso on tomato roots. The quantification of the relative
expression of srfA and rap genes suggested an inhibitory effect of the plasmidencoded
Rap-Phr system on surfactin synthesis. Moreover, on LB, the antagonistic
effect against phytopathogenic fungi was limited for S499 P-, most probably due to a verified reduction of iturin secretion. Although less clearly, an impact of plasmid
curing on the biocontrol ability was observed also on a medium (RE) that
reproduced the typical composition of plant root exudates. Globally, our results
show that pS499 differently modulates S499 phenotype depending on the
nutritional context. More evidences are required to prove that pS499 is relevant for
the fitness of the rhizobacterium in its natural environment
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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