1,720,977 research outputs found
Fatty Acids as Biomarkers of the Influence of Biological and Environmental Factors on Marine Organisms
Full text linkI lipidi come bioindicatori sono già stati utilizzati in diversi studi ed in differenti aree di ricerca, come per esempio: i) in studi di interazioni trofiche tra diversi organismi marini (catena alimentare), ii) in studi di biomassa e identificazione della tipologia di popolazione nei sedimenti marini, iii) per studiare la comunità algale all’interno del ghiaccio marino e iv) per analizzare la relazione tra inquinamento ambientale o condizioni ambientali stressanti con la risposta biologica degli organismi marini. Durante la mia ricerca, ho usato i lipidi (in particolare gli acidi grassi) come bioindicatori per studiare l’influenza di alcune variabili in diversi organismi marini. In particolare: l'effetto del tempo e della temperatura sul pesce antartico Trematomus bernacchii, l'influenza della taglia e del sesso sulla qualità del tonno rosso dell'Atlantico, e il cambiamento del profilo lipidico durante la maturazione della gonade femminile della mazzancolla (Penaeus kerathurus). I risultati mostrano che ogni cambiamento di fattori esterni (ambientale, dieta, ecc.) o interni (taglia, genere, ciclo biologico, ecc.) corrispondeva a un cambiamento del profilo lipidico, con una particolare influenza sulla composizione degli acidi grassi. In conclusione, lo studio del profilo lipidico o della composizione degli acidi grassi sono validi strumenti per comprendere la risposta di un organismo al cambiamento di una variabile esterna o interna. Inoltre, questo approccio può essere un importante studio che arricchisce e aiuta a comprendere le informazioni ottenute da indagini biochimiche e/o genetiche.Lipids as biomarkers have already been used in several studies, lied for example to: i) trophic interactions between different marine organisms (food chain), ii) the biomass and the typology of population in marine sediments, iii) the algal community of the sea ice and iv) the relationship between environmental pollution or stressful habitat conditions with the biological response of marine organisms. During my research, I used lipids (in particular fatty acids) as biomarkers to study the influences of some variables in different marine organisms. In particular: the effect of time and temperature on Antarctic fish Trematomus bernacchii, the influence of size and gender on meat quality of the Atlantic Bluefin tuna, the change in lipid profile during gonadal maturation of Caramote prawn Penaeus kerathurus. The results showed that every change in external (environmental, diets, etc.) or internal (size, gender, biological cycles, etc.) factors, corresponded to changes within the lipid profile, with a particular influence on fatty acid composition. In conclusion, the study of fatty acid composition or of lipid profiles are good instruments to understand the response of an organisms to an external or internal change. Furthermore, this approach can be a valuable complementary study to previous research involving biochemical and/or genetic investigations
Quantification of fatty acids in the muscle of Antarctic fish Trematomus bernacchii by gas chromatography-mass spectrometry: Optimization of the analytical methodology
No full textThis work presents data on the quantification of fatty acids (FAs, in terms of mass unit per tissue weight)
in the muscle of Trematomus bernacchii, a key species in Antarctica, often used as bioindicator for
contamination studies. Modifications in fatty acids content should be considered a useful biomarker to
study how contaminants affect Antarctic biota. Until now, very few studies quantified fatty acids of
muscle of T. bernacchii, and only as percentage of a single fatty acid on total lipids. To perform the
quantification of fatty acids, we used an analytical method based on a fast microwave-assisted extraction
of lipids from a lyophilized sample, a base-catalyzed trans-esterification of lipid extract to obtain Fatty
Acids Methyl Esters (FAMEs), and a separation and identification of FAMEs by gas chromatography-mass
spectrometry. With the optimized and validated method, a fast and accurate separation of Fatty Acids
Methyl Esters was performed in 43 min. The linearity was checked up to about 320 mg mL1; limit of
detection and limit of quantification are in the range 4e22 mgmL1 and 13e66 mgmL1, respectively. The
optimized method showed a good accuracy and precision. Major fatty acids were 14:0, 16:0, 16:1n7,
18:1n9, 18:1n7, 20:1n9, 20:5n3 and 22:6n3. Quantified FAs compute for about 47 mg g1 tissue dry
weight (dw), with 9.1 ± 0.1 mg g1 dw of saturated FAs, 25.5 ± 0.1 mg g1 dw of mono-unsaturated FAs,
and 12.2 ± 0.1 mg g1 dw of poly-unsaturated FA
Global Warming: Influence of Raising Temperature on Fatty Acid Composition of Muscle of Antarctic Teleost Trematomus Bernacchii, Analysed by Gas-Chromatography Mass-Spectrometry
No full text
The impact of seawater warming on fatty acid composition and nutritional quality indices of Trematomus bernacchii from the Antarctic region
Full text linkThere is a growing interest in exploiting Antarctic fisheries for human consumption. However, information on how the nutritional qualities of these resources will respond to the predicted seawater warming in the region for the next century is poor. The present research investigates changes in various nutritional indices of dietary importance (e.g. the ratio polyunsaturated to saturated fatty acids, the atherogenicity index, the thrombogenicity index, the hypo-cholesterolemic to hyper-cholesterolemic index, the health-promoting index, the flesh lipid quality and the ratio omega-3 to omega-6 index) by determining the fatty acid composition in muscle of Trematomus bernacchii (an Antarctic fish species) in its natural habitat (-1.87 °C) and warmer temperatures (0.0, 1.0, 2.0 °C). Comparison of the estimated nutritional indices at −1.87 °C with those at warmer temperatures revealed that seawater warming caused changes in the nutritional indices in the range of −12%<Δ < 30%. The observed changes were not statistically significant and ascribed to biological variability. Therefore, the nutritional values of T. bernacchii muscle were preserved after increasing the temperature of its natural habitat by + 4 °C. The present research is the first report describing the nutritional quality indices for an Antarctic fish species and the consequences of seawater warming on the nutritional value of T. bernacchii
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
Synthetic Feed Attractants in European Seabass (Dicentrarchus labrax) Culture: Effects on Growth, Health, and Appetite Stimulation
Full text linkSynthetic flavors from standardized processes have recently emerged as a promising and sustainable alternative to traditional feed attractants. In this study, two attractive (F25, cheese; F35, caramel) and one repulsive (F32-, coconut) synthetic flavors were individually added (1% w/w) to a commercial diet for European seabass (Dicentrarchus labrax) and tested over a 90-day feeding trial (30 fish per tank, in triplicate; initial weight 72.48 ± 8.04 g) to assess their impact on fish growth performance, welfare, and the modulation of brain appetite and monoaminergic pathways. None of the tested flavors negatively affected overall fish health. The F35 flavor enhanced feed intake (90.1 ± 5.6%) and growth (SGR 2.2 ± 0.2%) and positively influenced appetite-related and monoaminergic signals, thus being more effective than the F25 one (80.4 ± 3.2 and 1.6 ± 0.1%, respectively). A weekly feeding rotation between F35 and F25 (ROT group) resulted in suboptimal outcomes compared to F35 administration alone. The F32- flavor was not clearly perceived as strongly aversive by seabass and did not impair zootechnical performance. These findings highlight the potential of attractive synthetic flavors to improve diet palatability in a carnivorous species of commercial value, offering novel insights for more sustainable and cost-effective aquaculture feeding strategie
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