209 research outputs found
Origin and evolution of the Italian subterranean termite Reticulitermes lucifugus (Isoptera: Rhinotermitidae).
No full textThe Holarctic genus Reticulitermes shows seven species within the Mediterranean Basin. While phylogeny and systematics at continental level has been deeply investigated, a few studies concentrated on local ranges. To gain a clearer picture of the diversity and evolution of the Italian species Reticulitermes lucifugus, we analyzed the mitochondrial cytochrome oxidase II (COII) gene marker in newly collected colonies across the Peninsula. Data were gathered with all R. lucifugus sequences available from previous studies; COII sequences of the closely related Iberian taxa were also added to the data set. Maximum-likelihood, median-joining and statistical parsimony network elaborations on the resulting 119 colonies all agreed in indicating that: (i) the Sardo-Corsican subspecies R. lucifugus corsicus, strictly related to Southern Italian populations (including the Sicilian ones), is phylogenetically closer to the Iberian Reticulitermes grassei; and (ii) R. lucifugus lucifugus peninsular populations are structured into three clusters. The phylogenetic relationships and the biogeography of extant taxa suggest a scenario in which R. lucifugus ancestors colonized the Italian region through the Sardo-Corsican microplate during its Oligocene-Miocene anticlockwise rotation. Moreover, well after the colonization took place, northward range expansion might have produced the presently observed genetic diversity, as inferred from haplotype and nucleotide diversity estimates. On the whole, this study highlights the evolution of Italian Reticulitermes taxa and supports the importance of a wide taxon sampling especially when dealing with organisms easily dispersed by human activities
Phylogeography and colony structure of dry-wood dwelling termites of the genus Kalotermes (Isoptera, Kalotermitidae) in Southern Europe
No full textAccording to the most recent phylogenetic and phylogeographic investigations, the Kalotermes genus (Kalotermitidae) includes three different mitochondrial lineages of K. flavicollis and the new K. italicus species. In some Italian populations extreme colony fusion events were observed, with mixed families composed by up to nine maternal lines belonging to different genetic lineages or even to different species. In termites with the same nesting type, colony fusions lead to the death of queens and kings allowing false workers (pseudoergates) to evolve into reproducers and to inherit the colony (Accelerated Nest Inheritance). To widen the analyses on Kalotermes phylogeography and colony structure, we sequenced 912 bp of the mitochondrial genome, corresponding to COI/tRNA-Leu/COII, in two individuals from each of the 21 colonies collected in 11 European localities. In four colonies showing haplotypes of different genetic lineages/species, five-eight individuals per colony were further analyzed. A more detailed biogeographic scenario is obtained, with overlapping distribution areas of the considered lineages/species. Moreover, data confirm that mixed colonies with haplotypes of different genetic lineages/species may show more than two maternal lines. On the whole, colony fusions appear to occur more frequently than expected on the basis of eusociality models. Moreover, the possibility of hybridization between different genetic lineages or species could facilitate the fusion of more than two colonies wiping out mechanisms of nest-mate recognition. This analysis, therefore, demonstrates that dry-wood dwelling termites might be an interesting framework to study the evolution and maintenance of eusociality
Molecular systematics, biogeography, and colony fusion in the European dry-wood termites Kalotermes spp. (Blattodea, Termitoidae, Kalotermitidae)
No full textEuropean dry-wood termites belong to the genus Kalotermes (Kalotermitidae), one of the two termite genera in Europe. Until the recent description of two new species, Kalotermes italicus in Italy and Kalotermes phoenicae in the eastern Mediterranean area, Kalotermes flavicollis was the only taxon known in this region. The presence of additional entities, suggested by morphological and physiological variation observed in K. flavicollis, was supported by molecular studies revealing four distinct genetic lineages: lineage A, K. flavicollis sensu strictu, from the Aegean area to Italy; lineage B, in Tuscany; lineage SC, in Sardinia and Corsica; lineage SF, in southern France. Lineages A and B may form mixed colonies, suggesting hybridization. To draw a more detailed picture of Kalotermes evolution and biogeography in Europe, we analyzed samples from previously unsampled areas, such as Spain and southern Italy, by means of the highly informative cox1/trnL/cox2 mitochondrial DNA marker. Overall, phylogenetic analyses confirmed previously identified lineages and taxa, but widened the distribution of the lineage SC to the mainland and of the lineage SF to Spain and Portugal. Results further provided evidence for the synonymy between lineage B and K. italicus. Species delimitation analysis suggested that the three K. flavicollis lineages, as well as K. italicus, can be separate taxa. Data also suggest a possible interspecific hybridization between K. italicus and both K. flavicollis lineages A and SC
Preparation, Characterisation and Testing of Photocatalytic Polymeric Membranes with Entrapped or Suspended TiO2
No full textVarious cellulose triacetate (CTA) or polysulfone (PSf) membranes with entrapped polycrystalline TiO2 were prepared by using different methods of the so-called phase inversion process. Porosity and permeability of the membranes increased by increasing the amount of entrapped TiO2 while rejection decreased. The photoactivity of entrapped TiO2 for the degradation of congo-red was compared with that of the same quantity of suspended TiO2 and the results indicated that TiO2 was always more efficient when used in suspension. A hybrid configuration consisting of a continuous membrane photoreactor with the photocatalyst in suspension showed to be the most promising one
Left ventricle outflow tract vegetation, embolism and troponin rise: An infective endocarditis case report
No full textFILOGENESI DELLE TERMITI EUROPEE DEL LEGNO SECCO DEL GENERE KALOTERMES (ISOPTERA, KALOTERMITIDAE)
No full textLe sole termiti del legno secco native dell’Europa appartengono al genere Kalotermes. Fino a poco tempo fa, queste termiti erano considerate appartenenti alla sola specie Kalotermes flavicollis, distribuita in tutto il bacino del Mediterraneo. In due recenti studi, tuttavia, sono state descritte due nuove specie: K. italicus, in Italia, e K. phoenicae, a Cipro e nel Medio Oriente. Inoltre, studi di filogenesi molecolare hanno rivelato diverse linee di K. flavicollis: una in Corsica e Sardegna ed una nella Francia meridionale. Per ampliare le analisi sulla sistematica e la biogeografia di Kalotermes in Europa, sono state analizzate 43 colonie raccolte in 28 diverse località, insieme a campioni ottenuti da studi precedenti. Le analisi di filogenesi molecolare, condotte sul DNA mitocondriale, indicano i) che la distribuzione di K. italicus si estende dall'Italia centrale fino alla Francia meridionale, ii) che la linea Sardo-Corsa si trova anche nell’Italia continentale, e iii) che la linea della francese si estende fino alla penisola iberica. L’analisi dei cronogrammi, inoltre, hanno mostrato che le attuali Kalotermes europee si sono differenziate ~32 milioni di anni fa, con la separazione di K. phoenicae. Le specie K. italicus e K. flavicollis si sono separate ~15 milioni di anni fa, con le linee di K. flavicollis diversificatesi ~6 milioni di anni fa. In confronto alla storia evolutiva di un altro genere di termiti europee, Reticulitermes, è interessante notare come, sebbene si siano originate più di recente, queste ultime presentino una maggiore diversità. Le differenti caratteristiche ecologiche e/o di dinamica delle colonie possono spiegare questa differenza significativa
MILLSTONES COASTAL QUARRIES AS INDICATOR OF RELATIVE SEA LEVEL CHANGES
No full textThe Italian coasts shows numerous archaeological remains which reveals the activities that were
carried out along the coast for thousands of years of history. In order to use archaeological
structures for coastal studies, an accurate estimate of their relationship to the sea level at the time of
construction is required (Lambeck et al 2004, Antonioli et al 2007, Auriemma & Solinas 2009).
Millstone coastal quarries are only documented in southern Italy; they are carved on beachrock,
calcarenites and other sedimentary rock easy to be exploited. Few archaeological information have
been published about quarries for millstones extraction; they are documented since around 2500 yr
BP (Amouretti, 1986; Amouretti, Brun, 1993; Brun, 1997).
Millstone quarries carved within sandstone bedrocks and nowadays partially submerged was used
as archaeological sea level marker for two sites in Calabria and Sicily by Scicchitano et al.(2011).
In this study we analyzed 11 coastal sites of: Sicily (Capo d’Orlando, Letojanni, Giardini Naxos),
Calabria (Soverato, Tropea, Capo dell’Armi, Crotone, Roccella Ionica), Campania (Palinuro,
Scario) and Apulia (Polignano San Vito).
Thanks to the discovery and dating of an iron wedge used as tool for carving, for the first time we
can restrict the period of exploitation of this specific type of quarry (Ronchitelli, 1993). In addition,
based on geological knowledge of each sector and on measures made on the quarries, we present
considerations on functionality, geological uplift rate and reconstruction of possible ages of each
studied archaeological sites
Tumor necrosis factor-α inhibition of skeletal muscle regeneration is mediated by a caspase-dependent stem cell response
No full textSkeletal muscle is susceptible to injury following trauma, neurological dysfunction, and genetic diseases. Skeletal muscle homeostasis is maintained by a pronounced regenerative capacity, which includes the recruitment of stem cells. Chronic exposure to tumor necrosis factor-α(TNF) triggers a muscle wasting reminiscent of cachexia. To better understand the effects of TNF upon muscle homeostasis and stem cells, we exposed injured muscle to TNF at specific time points during regeneration. TNF exposure delayed the appearance of regenerating fibers, without exacerbating fiber death following the initial trauma. We observed modest cellular caspase activation during regeneration, which was markedly increased in response to TNF exposure concomitant with an inhibition in regeneration. Caspase activation did not lead to apoptosis and did not involve caspase-3. Inhibition of caspase activity improved muscle regeneration in either the absence or the presence of TNF, revealing a nonapoptotic role for this pathway in the myogenic program. Caspase activity was localized to the interstitial cells, which also express Sca-1, CD34, and PW1. Perturbation of PW1 activity blocked caspase activation and improved regeneration. The restricted localization of Sca-1+, CD34 +, PW1+ cells to a subset of interstitial cells with caspase activity reveals a critical regulatory role for this population during myogenesis, which may directly contribute to resident muscle stem cells or indirectly regulate stem cells through cell-cell interactions. ©AlphaMed Press
On the complementarity between on-the-job training and R&D: a brief overview
No full textIn this paper I briefly review the existing literature on the complementarity between on-the-job training and R&D. I show that the complementarity is studied, on the one hand, within two lines of economic research, labour economics and endogenous growth. On the other hand, from the empirical point of view, some recent papers seem to confirm results of theoretical studies, by arguing that a specific training for R&D is quite often a crucial condition for adopting new technologies. I conclude that this issue is treated by different subsets of economic literature which need other improvements, and particularly, an integration
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