1,721,018 research outputs found
Less is more: Low-cost in vitro propagation of an endangered Italian orchid
No full textOrchids are among the most widely distributed plants but also the most threatened by biotic and abiotic factors. Their interactions with specific symbiotic fungi during germination in natural environments make their propagation challenging for conservation biologists. In this study, in the framework of the European conservation project LIFEorchids, the germination protocol for the endangered Mediterranean species Orchis patens was optimised, and the effect of controlled constant temperature in growth chambers with fluctuations of temperature occurring in natural environments was compared. Seed viability was also evaluated by using a double-staining technique. Minimum, maximum and average daily temperatures were recorded for six months, from July to December, and germination percentages, as well as developmental stages of seeds, were annotated, for both conditions, every month. Even if germination was obtained under both conditions, the effect of temperature fluctuations was evident, by increasing the germination percentage of seeds from about 10% under controlled conditions to 59%. The latter result was almost comparable with seed viability data, indicating a strong impact of temperature fluctuations in breaking seed dormancy. Our results are a confirmation that temperature oscillations play a more important role than the average temperature in seed germination and suggest avoiding a constant temperature to optimise germination protocols for European orchid species
Monitoring a genetically engineered bacterium in a freshwater environment by rapid enzymatic amplification of a synthetic DNA "number plate".
No full textIn order to set up a sensitive and reliable detection method to monitor environmentally releases genetically engineered microorganisms (GEMs) a 72-bp, double-stranded DNA fragment has been built by annealing and ligating four synthetic oligonucleotides. Binding sites for two 20-mer oligonucleotides are situated inside the DNA fragment, flanking the centre. Into the central part of the construction a 30-nucleotide identification sequence has been fitted. Thanks to the presence of the two oligonucleotide binding sites, the synthetic construction ('number-plate') can be submitted to enzymatic amplification using the polymerase chain reaction (PCR), thus enabling the identification system to take advantage of the outstanding sensitivity of this technique. When released into a freshwater microcosm, cells of Pseudomonas putida carrying a 'number-plated' chromosome could be easily and rapidly detected merely by submitting boiled cell sediments to PCR amplification
Accessorio gelatiera per una impastatrice, kit gelatiera per una impastatrice e impastatrice [Sistema di aggancio ciotola] (estensione)
No full textTraditional, Therapeutic Uses and Phytochemistry of Terrestrial European Orchids and Implications for Conservation
No full textThe Orchidaceae family accounts for about 28,000 species, and most of them are mentioned in the folk medicine of nations around the world. The use of terrestrial orchids in European and Mediterranean regions has been reported since ancient times, but little information is available on their medicinal properties, as well as on their phytochemicals and biological activities. However, plant collection for human use is still listed as one of the main threats for terrestrial orchids, alongside other menacing factors such as wrong habitat management and disturbance to symbionts, such as pollinators and mycorrhizal fungi. Therefore, the primary aim of this review was to resume and discuss available information regarding the past and current popular uses of European orchids. We then grouped phytochemical data to evaluate the presence of bioactive compounds of pharmacological relevance, and we discussed whether these could support the therapeutic employment of the different organs. Finally, we briefly debated the sustainability of orchid utilizations, considering the different threatening factors and conservation actions including plant propagation methods
Genomics for the environment: the hidden power of bacteria
No full textPlants harbor a plethora of microorganisms with which they mutually interact, so to be considered as ‘super-organisms’. Plants are able to shape their associated microbiome and to recruit microbes useful for nutrition, growth and defense from pathogens and adverse environmental conditions. The genomics of plant associated microorganisms is then an emerging field with highly important outcomes for agriculture and, in general, for green biotechnologies. In the last years, an increasing number of genomes from plant-associated microorganisms have been sequenced, discovering an extraordinary number of genes potentially useful for biotechnology applications. This presentation will review some of
the relevant application of plant associated bacterial genomics and will focus on the exploration of the genome of the plant symbiont Sinorhizobium meliloti for genes relevant for the adaptation to heavy metal polluted soil. Heavy-metal tolerance in bacteria is indeed a widespread phenotype; in particular nickel tolerance has been characterized as depending on the nre system, which employs a Ni/H+ antiporter (NreB) to pump nickel out from the cell. An orthologous
of nreB gene was found in Sinorhizobium meliloti by genome scanning. The evolutionary origin of this gene and its functions have been extensively studied and a perspective for its potential biotechnology applications will be reviewed
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
Replicon-dependent bacterial genome evolution: The case of Sinorhizobium meliloti
No full textMany bacterial species, such as the alphaproteobacterium Sinorhizobium meliloti, are characterized by open pangenomes and contain multipartite genomes consisting of a chromosome and other large-sized replicons, such as chromids, megaplasmids, and plasmids. The evolutionary forces in both functional and structural aspects that shape the pangenome of species with multipartite genomes are still poorly understood. Therefore, we sequenced the genomes of 10 new S. meliloti strains, analyzed with four publicly available additional genomic sequences. Results indicated that the three main replicons present in these strains (a chromosome, a chromid, and a megaplasmid) partly show replicon-specific behaviors related to strain differentiation. In particular, the p SymB chromid was shown to be a hot spot for positively selected genes, and, unexpectedly, genes resident in the pSymB chromid were also found to be more widespread in distant taxa than those located in the other replicons. Moreover, through the exploitation of a DNA proximity network, a series of conserved "DNA backbones" were found to shape the evolution of the genome structure, with the rest of the genome experiencing rearrangements. The presented data allow depicting a scenario where the pSymB chromid has a distinctive role in intraspecies differentiation and in evolution through positive selection, whereas the pSymA megaplasmid mostly contributes to structural fluidity and to the emergence of new functions, indicating a specific evolutionary role for each replicon in the pangenome evolution. © 2013 The Author(s)
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
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