167 research outputs found
Chelarctus and Crenarctus (Crustacea: Scyllaridae) from Coral Sea waters, with molecular identification of their larvae
Chelarctus Holthuis, 2002 is widely distributed throughout the Indo-West Pacific, but its biogeographic patterns are unknown because Southern Hemisphere areas, such as the Coral Sea, remained poorly explored. Recent cruises organized by the Muséum national d'Histoire naturelle of Paris and the Australian Institute of Marine Science allowed the molecular identification of Crenarctus crenatus (Whitelegge, 1900), Chelarctus aureus (Holthuis, 1963) and Chelarctus crosnieri Holthuis, 2002 phyllosomae. The Coral Sea C. crenatus larvae are identical to stages IX and X of Scyllarus sp. Z, described in detail by Webber and Booth (2001). Descriptions of phyllosoma stages VI, IX and X of Ch. aureus and stages IX and X of Ch. crosnieri are also presented here. Morphological differences between Crenarctus and Chelarctus larvae are established for the first time and previous misidentifications in the literature are re-assessed
Diversity of Tanaidacea (Crustacea: Peracarida) in the World's Oceans – How Far Have We Come?
Tanaidaceans are small peracarid crustaceans which occur in all marine habitats, over the full range of depths, and rarely into fresh waters. Yet they have no obligate dispersive phase in their life-cycle. Populations are thus inevitably isolated, and allopatric speciation and high regional diversity are inevitable; cosmopolitan distributions are considered to be unlikely or non-existent. Options for passive dispersion are discussed. Tanaidaceans appear to have first evolved in shallow waters, the region of greatest diversification of the Apseudomorpha and some tanaidomorph families, while in deeper waters the apseudomorphs have subsequently evolved two or three distinct phyletic lines. The Neotanaidomorpha has evolved separately and diversified globally in deep waters, and the Tanaidomorpha has undergone the greatest evolution, diversification and adaptation, to the point where some of the deep-water taxa are recolonizing shallow waters. Analysis of their geographic distribution shows some level of regional isolation, but suffers from inclusion of polyphyletic taxa and a general lack of data, particularly for deep waters. It is concluded that the diversity of the tanaidomorphs in deeper waters and in certain ocean regions remains to be discovered; that the smaller taxa are largely understudied; and that numerous cryptic species remain to be distinguished. Thus the number of species currently recognized is likely to be an order of magnitude too low, and globally the Tanaidacea potentially rival the Amphipoda and Isopoda in diversity
Photochemical modification of polysulfone
Badano zmiany związane z fotochemiczną modyfikacją polisulfonu w oparciu o analizę spektralną naświetlanych próbek. Stwierdzono tworzenie połączeń karbonylowych, grup hydroksylowych a także obniżenie ilości grup eterowych i sulfonowych, które związane jest z degradacją polimeru. Obserwowany wzrost absorbancji w zakresie długofalowej części zakresu UV (?>290 nm) przypisano tworzeniu się sprzężonych struktur polifenylowych.The changes resulting from the photochemical modification of polysulfone were examined with the use of spectroscopic analysis of irradiated samples. The formation of carbonyl and hydroxyl groups in irradiated films and the reduction of the amount of ether and sulfone groups, connected with the degradation of the polymer were observed. The increase of the long wave UV absorption (?>290 nm) was attributed to the formation of polyphenyl conjugated structures
The impact of chemical and physical modification of polysulfone surface on cellular reactions in vitro
The effect of the carbon fibres diameter on cell response
W ramach pracy otrzymano włókninę zbudowaną z włókien o różnych średnicach i wielkości, której mikrostruktura posiada biomimetyczny charakter, tzn. składa się z włókien o średnicach zbliżonych do średnic włókien występujących w tkankach. Badania biologiczne wykazały, że włókna o niskich średnicach są gorzej tolerowane przez tkanki.A three dimensional fibrous material, made from fibres differing in diameters and porosity, has been designed and prepared. These materials will constitute a 3D scaffold containing fibrous components mimicking the structure of natural tissue. The biological studies indicate that the fibres with bigger diameter allow for more intense and quick regeneration of surrounding tissue
Integrative systematics and ecology of a new deep-sea family of tanaidacean crustaceans
A new family of paratanaoidean Tanaidacea – Paranarthrurellidae fam. nov. – is erected to accommodate two genera without family classification (Paratanaoidea incertae sedis), namely Armatognathia Kudinova-Pasternak, 1987 and Paranarthrurella Lang, 1971. Seven new species of Paranarthrurella and two of Armatognathia are described from material taken in different deep-sea areas of the Atlantic and Pacific oceans. The type species of Paranarthrurella — P. caudata (Kudinova-Pasternak, 1965) — is redescribed based on the paratype. The genus Cheliasetosatanais Larsen and Araújo-Silva, 2014 originally classified within Colletteidae is synonymised with Paranarthrurella, and Arthrura shiinoi Kudinova-Pasternak, 1973 is transferred to Armatognathia. Amended diagnoses of Armatognathia and Paranarthrurella genera are given. Choosing characters for distinguishing and defining both genera was supported by Principal Component Analysis. Designation of the new family is supported by molecular phylogenetic analysis of COI and 18S datasets. The distribution of all species currently included in the new family was visualised and their bathymetric distribution analysed
Composition and distribution of the peracarid crustacean fauna along a latitudinal transect off Victoria Land (Ross Sea, Antarctica) with special emphasis on the Cumacea
The following study was the first to describe composition and structure of the peracarid fauna systematically along a latitudinal transect off Victoria Land (Ross Sea, Antarctica). During the 19th Antarctic expedition of the Italian research vessel “Italica” in February 2004, macrobenthic samples were collected by means of a Rauschert dredge with a mesh size of 500 m at depths between 85 and 515 m. The composition of peracarid crustaceans, especially Cumacea was investigated. Peracarida contributed 63% to the total abundance of the fauna. The peracarid samples were dominated by amphipods (66%), whereas cumaceans were represented with 7%. Previously, only 13 cumacean species were known, now the number of species recorded from the Ross Sea increased to 34. Thus, the cumacean fauna of the Ross Sea, which was regarded as the poorest in terms of species richness, has to be considered as equivalent to that of other high Antarctic areas. Most important cumacean families concerning abundance and species richness were Leuconidae, Nannastacidae, and Diastylidae. Cumacean diversity was lowest at the northernmost area (Cape Adare). At the area off Coulman Island, which is characterized by muddy sediment, diversity was highest. Diversity and species number were higher at the deeper stations and abundance increased with latitude. A review of the bathymetric distribution of the Cumacea from the Ross Sea reveals that most species distribute across the Antarctic continental shelf and slope. So far, only few deep-sea records justify the assumption of a shallow-water–deep-sea relationship in some species of Ross Sea Cumacea, which is discussed from an evolutionary point of view
Hepatitis C virus quasispecies in chronically infected children subjected to interferon–ribavirin therapy
Accumulating evidence suggests that certain features of hepatitis C virus (HCV), especially its high genetic variability, might be responsible for the low efficiency of anti-HCV treatment. Here, we present a bioinformatic analysis of HCV-1a populations isolated from 23 children with chronic hepatitis C (CHC) subjected to interferon–ribavirin therapy. The structures of the viral quasispecies were established based on a 132-amino-acid sequence derived from E1/E2 protein, including hypervariable region 1 (HVR1). Two types of HCV populations were identified. The first type, found in non-responders, contained a small number of closely related variants. The second type, characteristic for sustained responders, was composed of a large number of distantly associated equal-rank variants. Comparison of 445 HVR1 sequences showed that a significant number of variants present in non-responding patients are closely related, suggesting that certain, still unidentified properties of the pathogen may be key factors determining the result of CHC treatment
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