98 research outputs found

    Molecular and morphological analyses confirm two new species of the Hydraena emarginata–saga clade (Coleoptera, Hydraenidae) from Spain and France

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    El documento auto-archivado en Digital.CSIC es el PRE-PRINT del autor. La versión definitiva se publicó posteriormente en Zootaxa 2760 : 29-38 (2011)Using morphological and molecular analyses, the existence of two undescribed species, H. diazi from north–eastern Spain and French Pyrenees, and H. fosterorum from north–central Spain is confirmed. These species are members of a European endemic complex of hydraenid beetles, the Hydraena emarginata–saga clade, belonging to the ”Haenydra“ lineage. The two new species are described and the geographic range of the widespread H. saga is revised.A visit of the first author to the NMW was supported by Synthesys (Application AT–TAF–53); the work of IR was funded by projects CGL2007–61665 and CGL2010–15755.Peer reviewe

    Epuraea imperialis (Reitter, 1877). New invasive species of Nitidulidae (Coleoptera) in Europe, with a checklist of sap beetles introduced to Europe and Mediterranean areas

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    Australian species Epuraea imperialis (Reitter, 1877), previously introduced to New Zealand, is recorded as a new invasive species from the Canary Islands, Continental Spain, Portugal, France, Belgium, and Italy. It is redescribed and figured, and its taxonomic position in the genus Epuraea Erichson, 1843 is discussed. A tentative checklist of sap beetles introduced to Europe and the Mediterranean areas is finally included

    Molecular biogeography of Mediterranean and southern African disjunctions as exemplified by pollen beetles of the Meligethes planiusculus species-group and related taxa (Coleoptera: Nitidulidae; Meligethinae)

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    We investigated the apparent disjunction expressed in two related assemblages of species of the genus Meligethes, i.e. M. fruticola and its allies in the Cape region of South Africa and the M. planiusculus group in the Mediterranean region. We also inferred possible dynamics in the radiation of the Meligethes planiusculus complex within Macaronesia utilizing morphological, molecular and bionomical data, exploring potential historical and palaeoecological scenarios regulated by a molecular clock dating system. We reconstructed phylogenetic relationships of the M. planiusculus complex and of related Mediterranean (M. tristis), tropical (M. scotti) and southern African (M. chevrolati, M. conformis, and M. fruticola) species, using COI mitochondrial gene sequences. Phylogenetic reconstructions support an unambiguous distinction of two major clades grouping European-Mediterranean M. canariensis, M. isoplexidis andM. planiusculus specimens in one clade and the South-African specimens related to M. fruticola in another. Molecular markers suggested that the European-Mediterranean taxon M. tristis is unambiguously more distantly related to the partly sympatric M. canariensis, M. isoplexidis and M. planiusculus, than to the geographically isolated Southern African taxon, M. fruticola. However, morphological data revealed that M. tristis is more closely related to M. planiusculus and its allies while occupying a position internal to the M. planiusculus species group, but external to the M. planiusculus complex. Results of divergence estimation analyses suggest a splitting between ancestors of the European-Mediterranean species of the M. planiusculus complex and that of the African species M. fruticola at ~21-23 MYA. Molecular results also demonstrated that the remaining Afrotropical species are more related to the M. planiusculus and M. fruticola complexes than to M. tristis. This evidence clearly indicates that the Holarctic M. planiusculus group represents a paraphyletic assemblage with heterochronic Afrotropical origin. The estimated times of divergence supports evidence from other researchers of an ‘Arid Corridor’, or of a ‘Central or Eastern High Africa Corridor’, which connected several times in the last twenty MY the European-Mediterranean and eastern/southern African areas, and facilitated species migration northwards and southwards. The dynamics of the Meligethes planiusculus complex radiation in Macaronesia apparently followed a contradictory biogeographical scenario than the sequence of events recently hypothesized for their host-plants (Echium, Boraginaceae)

    Epuraea imperialis (Reitter, 1877). New invasive species of Nitidulidae (Coleoptera) in Europe, with a checklist of sap beetles introduced to Europe and Mediterranean areas

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    Australian species Epuraea imperialis (Reitter, 1877), previously introduced to New Zealand, is recorded as a new invasive species from the Canary Islands, Continental Spain, Portugal, France, Belgium, and Italy. It is redescribed and figured, and its taxonomic position in the genus Epuraea Erichson, 1843 is discussed. A tentative checklist of sap beetles introduced to Europe and the Mediterranean areas is finally included

    New Species in the Old World: Europe as a Frontier in Biodiversity Exploration, a Test Bed for 21st Century Taxonomy

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    The number of described species on the planet is about 1.9 million, with ca. 17,000 new species described annually, mostly from the tropics. However, taxonomy is usually described as a science in crisis, lacking manpower and funding, a politically acknowledged problem known as the Taxonomic Impediment. Using data from the Fauna Europaea database and the Zoological Record, we show that contrary to general belief, developed and heavily-studied parts of the world are important reservoirs of unknown species. In Europe, new species of multicellular terrestrial and freshwater animals are being discovered and named at an unprecedented rate: since the 1950s, more than 770 new species are on average described each year from Europe, which add to the 125,000 terrestrial and freshwater multicellular species already known in this region. There is no sign of having reached a plateau that would allow for the assessment of the magnitude of European biodiversity. More remarkably, over 60% of these new species are described by non-professional taxonomists. Amateurs are recognized as an essential part of the workforce in ecology and astronomy, but the magnitude of non-professional taxonomist contributions to alpha-taxonomy has not been fully realized until now. Our results stress the importance of developing a system that better supports and guides this formidable workforce, as we seek to overcome the Taxonomic Impediment and speed up the process of describing the planetary biodiversity before it is too late

    Molecular evolution of a gene cluster of serine proteases expressed in the Anopheles gambiae female reproductive tract

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    <p>Abstract</p> <p>Background</p> <p>Genes involved in post-mating processes of multiple mating organisms are known to evolve rapidly due to coevolution driven by sexual conflict among male-female interacting proteins. In the malaria mosquito <it>Anopheles gambiae </it>- a monandrous species in which sexual conflict is expected to be absent or minimal - recent data strongly suggest that proteolytic enzymes specifically expressed in the female lower reproductive tissues are involved in the processing of male products transferred to females during mating. In order to better understand the role of selective forces underlying the evolution of proteins involved in post-mating responses, we analysed a cluster of genes encoding for three serine proteases that are down-regulated after mating, two of which specifically expressed in the atrium and one in the spermatheca of <it>A. gambiae </it>females.</p> <p>Results</p> <p>The analysis of polymorphisms and divergence of these female-expressed proteases in closely related species of the <it>A. gambiae </it>complex revealed a high level of replacement polymorphisms consistent with relaxed evolutionary constraints of duplicated genes, allowing to rapidly fix novel replacements to perform new or more specific functions. Adaptive evolution was detected in several codons of the 3 genes and hints of episodic selection were also found. In addition, the structural modelling of these proteases highlighted some important differences in their substrate specificity, and provided evidence that a number of sites evolving under selective pressures lie relatively close to the catalytic triad and/or on the edge of the specificity pocket, known to be involved in substrate recognition or binding. The observed patterns suggest that these proteases may interact with factors transferred by males during mating (e.g. substrates, inhibitors or pathogens) and that they may have differently evolved in independent <it>A. gambiae </it>lineages.</p> <p>Conclusions</p> <p>Our results - also examined in light of constraints in the application of selection-inference methods to the closely related species of the <it>A. gambiae </it>complex - reveal an unexpectedly intricate evolutionary scenario. Further experimental analyses are needed to investigate the biological functions of these genes in order to better interpret their molecular evolution and to assess whether they represent possible targets for limiting the fertility of <it>Anopheles </it>mosquitoes in malaria vector control strategies.</p

    The European union’s 2010 target: Putting rare species in focus

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    P. 167-185The European Union has adopted the ambitious target of halting the loss of biodiversity by 2010. Several indicators have been proposed to assess progress towards the 2010 target, two of them addressing directly the issue of species decline. In Europe, the Fauna Europaea database gives an insight into the patterns of distribution of a total dataset of 130,000 terrestrial and freshwater species without taxonomic bias, and provide a unique opportunity to assess the feasibility of the 2010 target. It shows that the vast majority of European species are rare, in the sense that they have a restricted range. Considering this, the paper discusses whether the 2010 target indicators really cover the species most at risk of extinction. The analysis of a list of 62 globally extinct European taxa shows that most contemporary extinctions have affected narrow-range taxa or taxa with strict ecological requirements. Indeed, most European species listed as threatened in the IUCN Red List are narrow-range species. Conversely, there are as many wide-range species as narrow-range endemics in the list of protected species in Europe (Bird and Habitat Directives). The subset of biodiversity captured by the 2010 target indicators should be representative of the whole biodiversity in terms of patterns of distribution and abundance. Indicators should not overlook a core characteristic of biodiversity, i.e. the large number of narrow-range species and their intrinsic vulnerability. With ill-selected indicator species, the extinction of narrowrange endemics would go unnoticedS

    Investigating orphan cytochromes P450 from Mycobacterium tuberculosis : the search for potential drug targets

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    Tuberculosis (TB) is a disease that the World Health Organisation (WHO) regards as a global pandemic. There is a great need for new drugs to combat this threat. Drug resistant strains of the causative agent, Mycobacterium tuberculosis (Mtb), have increased the urgency of this quest for novel anti-mycobacterial medicines. Publication of the Mtb genome sequence revealed a large number of cytochrome P450 (CYP) enzymes [Cole, S. T. et al. 1998]. These mono-oxygenase enzymes have been studied for many years and are responsible for metabolic functions in every kingdom of life. Research on the Mtb P450s to date has highlighted several of them as having critcal roles within the organism. CYP121 and CYP128 have been implicated as essential through gene knockout studies. It has been demonstrated that CYP125 is not essential for viability. However, it is part of a gene cluster highly important for Mtb infectivity and virulence. Due to the prospective importance of P450s to Mtb, this group of enzymes is under investigation as a source of novel drug targets. CYP142 was discovered as a potential drug target after it was located to a gene cluster involved in cholesterol catabolism during Mtb dormancy. As part of this PhD project, it was demonstrated that CYP142 performs an almost identical role to that reported for CYP125. These enzymes both perform C27 hydroxylation and carboxylation of the cholesterol side chain. However, variations in the level of oxidation have been identified, dependent upon the redox system with which these P450s are associated. A crystal structure of CYP142 showing high similarity in active site architecture to CYP125 supports the physiological role of CYP142 in cholesterol catabolism. Combining this with in vitro data which demonstrates that CYP142 possesses high affinity for a range of azole anti-fungal agents [Ahmad, Z. et al. 2005, 2006] supports the suggestion that it is a candidate target for the next generation of anti-mycobacterial drugs. CYP144 was highlighted as being important during the latent phase of Mtb growth, a phase that is not targeted by any of the current antimycobacterials. Work performed as part of this PhD has shown that many characteristics of CYP144 are highly comparable to those reported for other MtbP450s. CYP144 shows high affinity and specificity towards many azole molecules. Econazole, clotrimazole and miconazole have repeatedly been shown to bind to MtbP450s, including CYP144 and CYP142, with high affinity and are excellent potential candidates as novel anti-mycobacterial agents. An N-terminally truncated form of CYP144, CYP144-T, has been investigated in the pursuit of a CYP144 crystal structure. It is hoped that this will enable the elucidation of a physiological role for CYP144. Both CYP142 and CYP144 have demonstrated biochemical and biophysical characteristics that contribute to our knowledge of P450 enzymes. This PhD has established that CYP142 exhibits an equilibrium between P450 and P420 species in its CO-bound, ferrous form. A conversion from P420, and stabilisation of P450, upon substrate binding was also demonstrated. CYP144 displays unusual azole coordination characteristics when examined by EPR and removal of the CYP144 gene from Mtb increased sensitivity of the strain to clotrimazole. Studies of these enzymes has advanced knowledge of P450 and Mtb redox chemistry, established roles for the MtbP450 cohort and identified the potential of anti-mycobacterial drugs and associated targets.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    West Palaearctic taxa formerly connected to the ‘old’ genus&lt;i&gt;Atritomus &lt;/i&gt;Reitter, 1877 (Coleoptera, Mycetophagidae): taxonomy, distribution, and description of a new genus

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    The present study aims to resolve the taxonomic confusion involving several taxa within Mycetophagidae Leach, 1815, originating from the introduction of the genus Atritomus Reitter, 1877, and then by its subsequent controversial interpretation. A detailed overview of the taxonomic and nomenclatural history of the taxa previously linked to Atritomus is provided. The authors propose the introduction of Stereophilus Biscaccianti, Audisio &amp; Esser gen. nov. for Atritomus filicornis Reitter, 1887, and the restoration of Entoxylon Ancey, 1869 at the genus rank, together with some rectifications regarding the authorship and the date of publication of both Entoxylon and its type species, E. abeillei Ancey, 1869. Moreover, the Ethiopian species Atritomus vicinus Grouvelle, 1908 is herein transferred to the genus Typhaeola Ganglbauer, 1899 based on the examination of the holotype. The following new combinations are proposed: Entoxylon baudii (Seidlitz, 1889) comb. nov. (from Esarcus Reiche, 1864), Entoxylon besucheti (Dajoz, 1964) comb. nov. (from Esarcus subg. Entoxylon), Entoxylon franzi (Dajoz, 1964) comb. nov. (from Esarcus subg. Entoxylon), Entoxylon inexpectatus (Dajoz, 1964) comb. nov. (from Esarcus subg. Entoxylon), Entoxylon martini (Reitter, 1887) comb. nov. (from Esarcus), Stereophilus filicornis (Reitter, 1887) gen. et comb. nov. (from Atritomus), Typhaeola vicina (Grouvelle, 1908) comb. nov. (from Atritomus).</p
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