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排序方式: 共有489条查询结果,搜索用时 15 毫秒
71.
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Francesca Gherardi Sandro Bertolino Marco Bodon Sandra Casellato Simone Cianfanelli Marco Ferraguti Elisabetta Lori Graziella Mura Annamaria Nocita Nicoletta Riccardi Giampaolo Rossetti Emilia Rota Riccardo Scalera Sergio Zerunian Elena Tricarico 《Biological invasions》2008,10(4):435-454
The paper provides a list of the non-indigenous animal species occurring today in Italian inland waters. Xenodiversity was
found to amount to 112 species (64 invertebrates and 48 vertebrates), which contribute for about 2% to the inland-water fauna
in Italy. Northern and central regions are most affected, and Asia, North America, and the rest of Europe are the main donor
continents. The large majority of non-indigenous species entered Italy as a direct or indirect effect of human intervention.
A difference between invertebrates and vertebrates was found for their mode of arrival (unintentional for invertebrates and
intentional for vertebrates). Accidental transport, in association with both fish (for aquaculture or stock enhancement) and
crops, has been the main vector of invertebrate introductions, whereas vertebrates were mostly released for stocking purposes.
Overall stock enhancement (47.92%) and culture (37.5%) prevailed over the other pathways. Seventeen and 7 species of our list
are included among the 100 worst invasive species of Europe (DAISIE) and of the world (IUCN), respectively. For some (but
not all) non-indigenous species recorded in Italy the multilevel impact exerted on the recipient communities and ecosystems
is known, even if rarely quantified, but knowledge on their chronic impact is still missing. Additional research is needed
to provide criteria for prioritizing intervention against well established invaders and identify which new potential invader
should be targeted as “unwanted”. 相似文献
74.
75.
Banks AS Kon N Knight C Matsumoto M Gutiérrez-Juárez R Rossetti L Gu W Accili D 《Cell metabolism》2008,8(4):333-341
In yeast, worms, and flies, an extra copy of the gene encoding the Sirtuin Sir2 increases metabolic efficiency, as does administration of polyphenols like resveratrol, thought to act through Sirtuins. But evidence that Sirtuin gain of function results in increased metabolic efficiency in mammals is limited. We generated transgenic mice with moderate overexpression of SirT1, designed to mimic the Sirtuin gain of function that improves metabolism in C. elegans. These mice exhibit normal insulin sensitivity but decreased food intake and locomotor activity, resulting in decreased energy expenditure. However, in various models of insulin resistance and diabetes, SirT1 transgenics display improved glucose tolerance due to decreased hepatic glucose production and increased adiponectin levels, without changes in body weight or composition. We conclude that SirT1 gain of function primes the organism for metabolic adaptation to insulin resistance, increasing hepatic insulin sensitivity and decreasing whole-body energy requirements. These findings have important implications for Sirtuin-based therapies in humans. 相似文献
76.
Maria João Fernandes Martins Francesc Mezquita Olivier Schmit Juan Rueda Giampaolo Rossetti Tadeusz Namiotko 《Hydrobiologia》2009,636(1):219-232
Eucypris virens is a freshwater ostracod in which both sexual reproduction and parthenogenesis occur. Sympatric coexistence of both reproductive
modes is known in zones of overlap. This renders the species a potentially valuable model organism to study the ‘queen of
evolutionary problems’, i.e. why sex is so successful despite its costs (paradox of sex). In order to maximally exploit this
potential, a broad knowledge of the species’ ecology is essential, including an understanding of its life history and population
dynamics. Here, the phenology of the species was followed in three temporary ponds through monthly (Spain) or fortnightly
(Poland) samplings, throughout an inundation period. This study confirms the wide ecological tolerances of E. virens. Although the species is generally assumed to be univoltine, two hatching periods were observed in the Spanish sites. Biotic
interactions, especially predation, appear to be the important determinants of population dynamics in long-hydroperiod sites.
Abiotic conditions may influence population dynamics through their impact on egg hatching. In the site with male presence,
the initially female-biased sex ratio evolved towards a balanced sex ratio through the season. No consistent differences in
limb morphology were observed between females originating from the three study sites. On the other hand, valve size of adult
females varied among sites, possibly influenced by local environmental conditions (mainly salinity and pH) as well as the
expected genetic diversity. 相似文献
77.
78.
The influence of local (i.e. physico-chemical constraints) and regional (i.e. dispersal) processes in determining the structure of zooplankton communities in lentic waters was analysed in a mountain district of 4500 km2 (northern Apennines, Italy). In the 47 lakes and ponds considered in this study, a total of 139 taxa were found. Surface area (SA) and maximum depth (Zmax) significantly influenced species richness and nestedness, stressing the importance of habitat availability for zooplankton diversity and composition. Species richness and nestedness did not correlate with site isolation, indicating low influence of dispersal for these community properties. A negative relationship between the similarity in species composition among sites and their mutual geographic distance was also found. The relative importance of different sources of compositional variation was quantified by direct ordination. Local environmental conditions (i.e. Zmax, altitude, pH and conductivity) accounted for 65.9 % of the variation in rotifer assemblages. The importance of environmental constraints in structuring zooplankton communities was best documented by the microcrustacean distribution in the study area, which was mainly correlated (73.4 % of the variation in the species data) with water ionic content, surface area and hydroperiod of the habitats.Although previous studies on processes shaping zooplankton assemblages that operate at different scales have yielded contrasting results, our data provide clear evidence for a major role of local constraints. 相似文献
79.
Raffaele Lombardi Patrizia Circelli Maria Elena Villani Giampaolo Buriani Luca Nardi Valentina Coppola Linda Bianco Eugenio Benvenuto Marcello Donini Carla Marusic 《BMC biotechnology》2009,9(1):96
Background
In recent years, different HIV antigens have been successfully expressed in plants by either stable transformation or transient expression systems. Among HIV proteins, Nef is considered a promising target for the formulation of a multi-component vaccine due to its implication in the first steps of viral infection. Attempts to express Nef as a single protein product (not fused to a stabilizing protein) in transgenic plants resulted in disappointingly low yields (about 0.5% of total soluble protein). In this work we describe a transient expression system based on co-agroinfiltration of plant virus gene silencing suppressor proteins in Nicotiana benthamiana, followed by a two-step affinity purification protocol of plant-derived Nef. 相似文献80.
Anna Lange Consiglio Maria Elena Dell'Aquila Nadia Fiandanese Barbara Ambruosi Yoon S Cho Giampaolo Bosi Silvana Arrighi Giovanni M Lacalandra Fausto Cremonesi 《Reproductive biology and endocrinology : RB&E》2009,7(1):113-11