23 research outputs found

    Mitochondrial DNA Regionalism and Historical Demography in the Extant Populations of Chirocephalus kerkyrensis (Branchiopoda: Anostraca)

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    Background: Mediterranean temporary water bodies are important reservoirs of biodiversity and host a unique assemblage of diapausing aquatic invertebrates. These environments are currently vanishing because of increasing human pressure. Chirocephalus kerkyrensis is a fairy shrimp typical of temporary water bodies in Mediterranean plain forests and has undergone a substantial decline in number of populations in recent years due to habitat loss. We assessed patterns of genetic connectivity and phylogeographic history in the seven extant populations of the species from Albania, Corfu Is. (Greece), Southern and Central Italy. Methodology/Principal Findings: We analyzed sequence variation at two mitochondrial DNA genes (Cytochrome Oxidase I and 16s rRNA) in all the known populations of C. kerkyrensis. We used multiple phylogenetic, phylogeographic and coalescence-based approaches to assess connectivity and historical demography across the whole distribution range of the species. C. kerkyrensis is genetically subdivided into three main mitochondrial lineages; two of them are geographically localized (Corfu Is. and Central Italy) and one encompasses a wide geographic area (Albania and Southern Italy). Most of the detected genetic variation (<81%) is apportioned among the aforementioned lineages. Conclusions/Significance: Multiple analyses of mismatch distributions consistently supported both past demographic and spatial expansions with the former predating the latter; demographic expansions were consistently placed during interglacial warm phases of the Pleistocene while spatial expansions were restricted to cold periods. Coalescence methods revealed a scenario of past isolation with low levels of gene flow in line with what is already known for other co-distributed fairy shrimps and suggest drift as the prevailing force in promoting local divergence. We recommend that these evolutionary trajectories should be taken in proper consideration in any effort aimed at protecting Mediterranean temporary water bodies

    Life history of <i>Tanymastigites perrieri</i> (Anostraca) in relation to temperature

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    Growth, longevity, and reproduction of Tanymastigites perrieri (Daday, 1910) have been studied under standardized laboratory conditions at six different temperature regimes: 10, 20, 25, 30, 35, and 40°C. The development D of the shrimps as a function of the temperature T is expressed as K = D(T - Q. The temperature at which development stopped is C = 4.32°C, while K is a thermal constant, the number of degrees-days above threshold, or the physiological time (K = 719 degrees-days). The highest growth rate occurred at 25°C. The greatest body size, however, was attained in animals reared at 10d°C (22 mm). Longevity decreased with increasing temperatures (from 41 days to 4 days). Maturation time was inversely related to temperature (from 20 days to 4 days; at 40°C no larvae survived). Offspring per individual varies with temperature (maximum 447 eggs at 20°C); while the innate capacity for increase, r, fluctuates between 0.07 and 0.34

    Odporność zarodników na warunki technologiczne procesu wytłaczania stopu polimeru

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    With the increasing demand for functionalised textile materials, industry is focusing on research that will add novel properties to textiles. Bioactive compounds and their benefits have been and are still considered as a possible source of unique functionalities to be explored. However, incorporating bioactive compounds into textiles and their resistance to textile process parameters has not yet been studied. In this study, we developed a system to study the resistance of Bacillus amyloliquefaciens spores against melt extrusion process parameters, like temperature (21, 200, 250, 300 °C), pressure (0.1, 0.6 and 1.0 MPa) and residence time (0, 1 and 10 minutes). The spores were successfully embedded in PET (polyethylene terephthalate) films and fibres through melt extrusion. Afterwards the survival rate of the spores was determined after extrusion and the data was used to develop a quadratic equation that relates the survival rate to the spore concentration.Wraz ze wzrostem zainteresowania funkcjonalizacją tekstyliów, przemysł skupia swoją uwagę na badaniach, dzięki którym można nadać nowe właściwości tekstyliom. Bioaktywności produktów jest jednym z czynników, które mają bardzo duże znaczenie. Jednakże możliwości wprowadzania substancji bioaktywnych do stosowanych materiałów włókienniczych nie są dostatecznie poznane. W pracy przedstawiono badania pozwalające na określenie odporności zarodników Bacillus amyloliquefaciens na warunki procesu wytłaczania stopów polimerów. Badania prowadzono przy temperaturach 21, 200, 250, 300 °C, ciśnieniach 0.1, 0.6 and 1.0 MPa oraz czasie oddziaływania 1 i 10 minut. Zarodniki wprowadzono do stopu PET i wytłaczano w postaci folii i włókien. Określono zależności przeżycia zarodników w zależności od ich stężenia w stopie polimerów

    Właściwości morfologiczne i strukturalne włókien z polietylenu tereftalatu domieszkowanych zarodnikami

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    Owing to the current demand for textiles with new functionalities and improved properties, there has been a continuous effort to modify Polyethylene terephthalate (PET) materials. In our previous study, we demonstrated that Bacillus amyloliquefaciens spores can be incorporated into PET fibres during extrusion. However, the extent to which they can be incorporated without fundamentally changing the properties of the fibres is unknown. In this work, scanning electron microscopy (SEM), transmission electron microscopy (TEM), optical microscopy (OM), differential scanning calorimetry (DSC), a Favimat tensile tester, and Raman and Fourier transform infrared spectroscopy (FT-IR) were used to study the properties of PET/spore fibres. The tensile strength, Young’s modulus and elongation at break were dependent on the spore concentration. Additionally the degree of crystallinity increased slightly, whereas the melting and crystallisation temperatures remained constant at all spore concentration levels. Nevertheless the properties of the fibres fall within the acceptable range of variation and are found to be as good as normal PET fibres.Biorąc pod uwagę zapotrzebowanie na tekstylia o polepszonych właściwościach i nowych właściwościach funkcyjnych prowadzone są ciągłe badania nad modyfikacyjny z polietylenu tereftalanowego (PET). W naszej poprzedniej pracy wykazaliśmy,ze zarodniki Bacillus amylliquefaciens można wprowadzić do włókien PET w czasie ich wytłaczania. Teraz badano w jakiej ilości zarodniki te można wprowadzić do włókien bez fundamentalnej zmiany ich właściwości. W pracy stosowano mikroskopie optyczna, SEM, TEEM jak również różnicową kalorymetrie skaningową (DSC), spektroskopię FTIR oraz Ramana oraz badania wytrzymałościowe. Stwierdzono,ze wytrzymałość na rozciąganie, moduł Younga oraz wydłużenie przy zerwaniu zależą od stężenia zarodników we włóknie. Dodatkowo stwierdzono, że stopień krystaliczności lekko wzrasta, podczas gdy temperatura topnienia i krystalizacji pozostają stałe przy wszystkich stosowanych stężeniach zarodników. Badania pozwoliły stwierdzić,ze właściwości włókien z zarodnikami są w granicach akceptowalnych zmian normalnych włókien PET

    Effects of anthropogenic factors on spider communities (Arthropoda: Araneae) in Chréa National park (Blida, Algeria)

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    Chrea National Park, one of the 11 national parks in Algeria, is natural and diverse but under different pressures: urbanisation, fires caused by the high flux of visitors. Several ecological and systematic studies have been conducted on the Araneae, the most important epigeal fauna, but no attention was given to the anthropogenic parcels of the Park. To assess the effects of urbanisation and fires on the ecology of this fauna, spiders were collected monthly for 2 years, using 'Pitfall' traps in three disturbed stations: burned, urbanised and reforested and three natural sites as control. In total, 1,476 specimens were sampled (19 families, 42 genera and 68 species). Zodarion algericum was the dominant species (13.25%), particularly in the burned station. Mann-Whitney U test showed a significant difference between urbanised and nonurbanised sites in contrast to other ones and no significant differences with the control. Our results show that fires transform the forest into a mosaic of habitats, with open gaps of different stages of succession. In addition, the reforestation of cedars without any agricultural practices has no negative effects on the Park. No loss of biodiversity was observed; this would encourage the restoration of the forest to protect its fauna and flora
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