1,720,970 research outputs found
Genetic diversity and structure of Megabalanus azoricus in the Azores: Implications for aquaculture management
No full textMegabalanus azoricus giant barnacles are the most traditional seafood of the Azores archipelago (NE Atlantic). This valuable commercial species has been highly exploited in the past and it is considered one of the key species for the development of aquaculture in the region. Despite the importance for conservation and aquaculture there is still a lack of basic information about M. azoricus genetic diversity and population structure. Here we used seven microsatellites markers to analyse 300 samples collected at six out of nine islands of the Azores archipelago, including also different locations from a single island, to provide information on the scale of genetic diversity and population structure of this species. Parameters like heterozygosity, allelic richness and effective number of alleles indicated a high genetic diversity and variability among islands. Pairwise comparisons and PCoA analysis on FST and Jost's DEST showed significant and evident differentiation among sampling locations. Additionally, AMOVA allocates a small (6.02%) but statistically significant portion of the variance to the among Island level revealing also a weak resolution (1.87%) at finer scale. Additionally Monte Carlo resampling methods indicated the most likely sources of the recruits were the local or adjacent populations. Genetic risks associated with the giant barnacle potential production scheme should be taken into account in a future management plan delimiting, as precautionary measure, this culture at a single island or at groups of islands here identified. Moreover a monitoring strategy should be implemented with the aim to evaluate possible changes in genetic parameters of native populations
A technical application of quantitative next generation sequencing for chimerism evaluation
Full text linkThe conservation of Apis mellifera (Linnaeus, 1758) in the Karst and Istria
No full textGenetic analyses conducted on bee samples from Istrian Karst have revealed the presence of a high degree of genetic reshuffling of local populations due to repeated imports of non-native bees for commercial purposes. Nevertheless, genetic traces of two presumably native ecotypes are still present. The first is a hybrid between the yellow Italian bee and the grey Carniolan bee and was found mainly in the area of the Karst above Trieste, the natural boundary between the two subspecies. The second, more abundant in Istria, could be the Istrian-Dalmatian ecotype, which is described in the literature as a coastal form of the Carniolan bee adapted to the warmer drier climate of the coastal Karst. These two ecotypes are morphologically very similar, but distinct from a genetic perspective. The identification and characterization of these local strains is a first step to implementing targeted programmes for the conservation and the restoration of their rearing. It then becomes of primary importance to create regulations that prohibit the introduction of non-native bees in the area to curb the risk of extinction of local varieties
Physiological and molecular responses of bivalves to toxic dinoflagellates
No full textDinoflagellates and other microalgae can produce a wide spectrum of toxic molecules, which are the main responsible of shellfish poisoning syndromes. During seasonal harmful algal blooms (HABs), many filter-feeding marine invertebrates, including bivalve molluscs, can accumulate phycotoxins at extremely high levels, thus representing a serious threat to human health. Furthermore, HABs also have a severe impact on the aquaculture sector due to the forced prolonged closure of large harvesting areas. Although the targets and mechanism of action of many phycotoxins have been extensively studied on vertebrate model organisms, so far just a little attention has been focused on their effects on marine invertebrates. Here we provide an overview about the molecular response of marine bivalves to phycotoxins, with a particular focus on toxins produced by dinoflagellates. Even though large-scale genomic and proteomic approaches on molluscs are still hindered by the limited molecular knowledge of these organisms, a few studies exploiting the most recent technological advances provide promising perspectives for a better comprehension of the mechanisms involved in shellfish toxicity and for the identification of molecular markers of contamination
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
ASPETTI DELLA BIOLOGIA ED ANALISI DEL CICLO RIPRODUTTIVO DI GOBIO BENACENSIS (POLLINI, 1816) NEL NORDEST ITALIA BIOLOGY ASPECTS OF GOBIO BENACENSIS (POLLINI, 1816) IN NORTHEAST ITALY
No full textThe aim of the present work is to study the biology and the reproductive cycle of the Italian gudgeon
Gobio benacensis, which is included as “endangered” (EN) in the IUCN Redlist, due to the
endangered status, information could be useful for the correct management of the species and for the
scheduling of focused conservation plans. Analyses were carried out within a watercourse included
in the Isonzo River Basin (Reca Stream, Northeast Italy) and regarded 86 specimen collected during
April 2016 in order to assess population consistence and structure, and 77 specimens collected
monthly and bimonthly between April 2016 and February 2017 to investigate the reproductive cycle.
Regression between total length (TL) and body weight (W) obtained for males (W=0,1253TL2,8770)
54 2
and females (W=0,1555TL2,7554) were analyzed using the ANCOVA and did not show significant
differences. Mean values of the gonadosomatic index (GSI) ranged from 0,61±0,49 and 1,75±0,58
for males and from 1,02±0,88 and 14,15±2,80 for females. Hepatosomatic index (HIS) showed ranges
between 0,05±0,02 and 2,68±1,26 for males and between 0,25±0,19 e 1,75±0,58 for females.
Analyses of ovaries and testicles, firstly performed for this species, allowed to identify maturation
stages. The results show that G. benacensis females repeatedly spawn during the reproductive period
between April and June and that males prolonged reproductive activity until August
dentification of host-pathogen interacting molecules of Mytilus galloprovincialis (Lamark, 1819) using phage-display technology.
No full text2013/2014Le cellule di mollusco immunocompetenti, in primis gli emociti circolanti, provvedono ad una rapida e robusta risposta difensiva nel confronti dei potenziali patogeni. Una volta che gli emociti vengono attivati dall'interazione tra pattern molecolari (PAMPs) presenti sulla superficie dei patogeni e specifici PRRs (pattern recognition receptors) in grado di riconoscerli, queste cellule innescano reazioni difensive. Nonostante un numero sempre più elevato di molecole in grado di interagire con i PAMPs sia stato caratterizzato in M. galloprovincialis, ad oggi non è mai stato effettuato uno studio di interattomica per l’identificazione su larga scala dei PRRs di mitilo coinvolti nel riconoscimento di specifici patogeni. Lo scopo di questo studio è, dunque, quello di identificare i PRRs delle cellule di mollusco immunocompetenti coinvolti nel riconoscimento dei batteri Vibrio splendidus e V. aestuarianus, Gram-negativi presenti in acque costiere e associati ai casi di mortalità che hanno colpito gli allevamenti di ostriche in tutto il mondo e verso i quali i mitili mostrano, invece, notevole resistenza . Per eseguire questo tipo di analisi è stata utilizzata, in modo innovativo, la tecnica phage-display, che si basa sulla possibilità di far esprimere ad un batteriofago un peptide esogeno in fusione con una delle proteine del capside, in modo che la particella fagica esponga sulla sua stessa superficie il peptide di interesse. Il nuovo approccio utilizzato in questo studio ha permesso lo studio diretto dell’interazione tra i fagi recanti un pool di peptiti espressi da emociti di mitilo e i PAMPs presenti sulla superficie delle cellule batteriche. Mediante successive fasi di selezione e amplificazione delle particelle fagiche in grado di legarsi alla superficie dei batteri, è stato possibile arricchire la frazione di cDNA di mitilo codificante PRRs. Con tecniche di sequenziamento massivo e strumenti bioinformatici è stato poi possibile risalire a tutte le sequenze codificanti i peptidi selezionati. I risultati ottenuti indicano che vi è una notevole differenza tra il numero di PRRs di emociti di mitilo che ha interagito con V. splendidus ripetto a V. aestuarianus. Lo studio si è, quindi, incentrato sui 42 peptidi selezionati contro V. splendidus, presunti PRRs, identificandone alcuni con funzione immunitaria già nota (C-type lectin, FREPs, C1qDC proteina, apextrin-related proteina), alcuni presumibilmente falsi positivi ed altri completamente nuovi che non mostrano similarità con sequenze omologhe annotate e il cui ruolo e funzione andrebbero indagati con futuri studi sperimentali.XXVII Ciclo198
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