264 research outputs found
A tiny new species of Platypelis from the Marojejy National Park in northeastern Madagascar (Amphibia: Microhylidae)
We describe a tiny new frog species of the genus Platypelis (Anura: Microhylidae: Cophylinae) from Marojejy National Park, northeastern Madagascar. Platypelis ravus sp. nov. differs from all other known Platypelis and Cophyla species by its small size (17-19 mm snout-vent length) and a combination of other morphological and bioacoustic characters. The new species seems to be most closely related to P. milloti with which it shares the principal colour pattern, but exhibits a yellow rather than red posterior venter. Uncorrected pairwise sequence divergence in a 16S rRNA gene fragment to all other known species of the genus (except P. cowanii for which no genetic data is available) is greater than 6%. We suggest the inclusion of the new species in the IUCN threat category “Data Deficient”
Galenische Entwicklung eines Insektenrepellents mit verbesserter Haftfestigkeit
Insektenrepellents wie N,N-Diethyltoluamid (DEET) wirken in der Dampfphase über der Haut, deshalb kann die Wirkdauer durch mechanischen Abrieb der Formulierung von der Haut, Penetration mit anschließender transdermaler Resorption und Abwaschen durch Schweiß oder Regen verkürzt werden. Alkoholische Lösungen von DEET, die in gemäßigten Klimazonen einen Schutz von sechs bis acht Stunden gegen zahlreiche Insektenarten gewährleisten, haben in tropischen Regionen eine deutlich verkürzte Wirkdauer von beispielsweise nur 2 Stunden. Zielsetzung dieser Arbeit war, eine Formulierung zu entwickeln, die auch bei tropischem Klima durch verbesserte Haftfestigkeit länger Schutz bietet. Im Rahmen dieses Projektes wurden mit Hilfe von Faktorenversuchsplänen vier Generationen von Cremeformulierungen entwickelt, deren Haftfestigkeit bei gleichem DEET-Gehalt deutlich größer ist als bei alkoholischen Lösungen, wie dem bei der Bundeswehr eingeführten Insektenschutzmittel BW. Im Vergleich zum Insektenschutzmittel BW wurde die Haftfestigkeit einer optimierten Formulierung um das 30-fache erhöht. Wesentlich für die Verbesserung ist der Einsatz von Carbomeren (Pemulen® Tr 1 NF) und Bis-diglyceryl-polyacyladipat (Softisan 649®), das bereits als Hilfsstoff in einem zugelassenen Arzneimittel verwendet wird. Durch quantitative Auswertung des Bewegungsmusters von Mücken der Gattung Aedes aegypti mit Hilfe einer elektronischen Kamera und Bildanalyse-Software wurde gezeigt, dass die neuen Zubereitungen hinsichtlich der initialen Repellent-Wirkung den alkoholischen Lösungen mindestens gleichwertig sind. Die Wirkstofffreisetzung aus den neuen Zubereitungen wurde in vitro mit Hilfe der Franzzelle mit derjenigen aus der alkoholischen Lösung verglichen. Das Ausmaß und die Geschwindigkeit der Permeation des Wirkstoffs aus der Grundlage konnte durch den Einsatz von hochmolekularen Hilfsstoffen und Viskositätserhöhung der äußeren Phase deutlich verringert werden. Durch die Herstellung von Zubereitungen im Großansatz mit einer Zahnkolloidmühle konnte der Dispersitätsgrad gegenüber der Herstellung in Salbenschale und Stephanmischer erhöht und eine engere Tröpfchengrössenverteilung erreicht werden. In einigen Formulierungen wurden bereits unmittelbar nach der manuellen Herstellung in der Salbenschale optisch anisotrope Strukturen beobachtet, die als Kristallisate von Emulgatorkomponenten gedeutet wurden. Das Fließverhalten aller neu entwickelten Zubereitungen war plastisch- oder pseudoplastisch-thixotrop. Nach sechsmonatiger Lagerung bei unterschiedlichen Bedingungen nahm die Viskosität generell ab und anisotrope Strukturen traten stärker hervor. Durch Verdunstung flüchtiger Komponenten nahm der Wirkstoffgehalt geringfügig zu, blieb aber innerhalb der für Arzneimittel akzeptablen Grenzen. Die optimierte Rezeptur war nach sechsmonatiger Lagerung im Schaukeltest sowie unter tropischen Bedingungen optisch stabil, sie war den anderen getesteten Zubereitungen hinsichtlich Haftfestigkeit, Repellentwirkung und Wirkstofffreisetzung in den in-vitro-Experimenten überlegen oder gleichwertig. Ob mit diesen Untersuchungen das Ziel einer Verlängerung der Wirkdauer in tropischen Klimazonen erreicht wurde, kann im Labormodell nicht gezeigt werden. Hierzu sind Feldversuche erforderlich, die über den Rahmen dieser Arbeit hinausgehen.Galenical Development of an insect repellent with enhances adhesiveness The effect of insect repellents like N,N-Diethyltoluamide (DEET) depends upon their concentration in the vapour phase above the skin. Their duration of effectiveness can be shortened by mechanical abrasion from the skin, dermal penetration with subsequent absorption and removal by sweat or rain. In temperate climates, alcoholic DEET solutions protect their users for six to eight hours against numerous species of insects, in tropical climates this time span can be reduced to about two hours. The objective of the present study was to develop a formulation with improved adhesiveness and prolonged protection even under tropical conditions. For this purpose, four generations of creams containing 30% DEET were formulated according to factorial experimental designs. The adhesiveness of the optimal formulation was increased by a factor of 30 over that of the alcoholic solution used by the German armed forces (Insektenschutzmittel BW). The improvement is largely due to the use of Carbomer (Pemulen® TR 1 NF) and Bis-Diglyceryl-polyacyladipate (Softisan 649®) as polymeric excipients. The repellent effect of these creams was assessed in vitro by quantitative evaluation of the patterns of movement of Aedes aegypti mosquitoes using an electronic camera and picture analysis software. It was found that the new formulations were at least equivalent to the alcoholic solutions concerning their initial repellent effect. Drug release patterns were assessed in vitro using the Franz Cell. Both amount and rate of DEET release from the creams were significantly decreased by the addition of macromolecular excipients and an increased viscosity of the external phase. The amount and size of anisotropic crystalline structures visible under the microscope in polarized light and the rheological properties of the formulations depended significantly upon the methods of preparation. Initial batches were prepared manually by mortar and pestle, intermediate ones using a blender and larger ones in a colloid mill. This led to a higher degree of dispersion and a narrower droplet-size distribution. In general, the new formulations displayed plastic-thixotropic or pseudoplastic-thixotropic rheological behaviour. After six month of storage under different conditions, the viscosity decreased and optically anisotropic structures became more prominent. DEET content increased slightly because volatile components evaporated. The optimal formulation was visually stable after six months of storage under tropical climatic conditions and after thermal cycling. It was found to be superior or equal to the alternatives tested in vitro with respect to adhesiveness, repellent effectiveness and release of th active ingredient. The final proof of a repellent formulation, however, remains field-testing, which was beyond the scope of this project
The taxonomic status of Hyla roeschmanni De Grys, 1938 (Anura: Hylidae)
Accepted by S. Carranza: 18 May 2006; published: 12 Jun. 2006The taxonomic status of Hyla roeschmanni De Grys, 1938 (Anura: Hylidae) is reviewed. We place Hyla roeschmanni as a junior synonym of Hypsiboas raniceps Cope, 1862. Because the holotype of Hyla roeschmanni was destroyed, we designate a neotype from Department Beni, Bolivia, and provide a description of the neotype.This work was partially funded by the projects REN/GLO 2001-1046 and CGL2005-03156 of the Spanish Ministry of Education and Science (I. De la Riva, Principal Investigator).Peer reviewe
Species complexes and the importance of Data Deficient classification in Red List assessments: The case of Hylobatrachus frogs
This work is licensed under a Creative Commons Attribution 4.0 International License.Taxonomy is the cornerstone of extinction risk assessments. Currently, the IUCN Red List treats species complexes either under a single overarching species name—resulting in an unhelpfully broad circumscription and underestimated threat assessment that does not apply to any one species lineage—or omits them altogether—resulting in the omission of species that should be assessed. We argue that taxonomic uncertainty alone, as in species complexes, should be grounds for assessment as Data Deficient (DD). Yet, use of the DD category is currently discouraged, resulting in assessments based on poor data quality and dismissal of the importance of taxonomic confidence in conservation. This policy may be leading to volatile and unwarranted assessments of hundreds of species across the world, and needs to be revised. To illustrate this point, we here present a partial taxonomic revision of torrent frogs from eastern Madagascar in the Mantidactylus subgenus Hylobatrachus. Two named species, Mantidactylus (Hylobatrachus) lugubris and M. (H.) cowanii, and several undescribed candidate species are recognised, but the application of the available names has been somewhat ambiguous. In a recent re-assessment of its conservation status, M. (H.) lugubris was assessed including all complex members except M. (H.) cowanii within its distribution, giving it a status of Least Concern and distribution over most of eastern Madagascar. After describing two of the unnamed lineages as Mantidactylus (Hylobatrachus) atsimo sp. nov. (from southeastern Madagascar) and Mantidactylus (Hylobatrachus) petakorona sp. nov. (from the Marojejy Massif in northeastern Madagascar), we show that Mantidactylus (Hylobatrachus) lugubris is restricted to the central east of Madagascar, highlighting the inaccuracy of its current Red List assessment. We propose to re-assess its status under a more restrictive definition that omits well-defined candidate species, thus representing the actual species to which its assessment refers, to the best of current knowledge. We recommend that for species complexes in general, (1) nominal lineages that can be confidently restricted should be assessed under the strict definition, (2) non-nominal species-level lineages and ambiguous names should be prioritised for taxonomic research, and (3) ambiguous names should be assessed as DD to highlight the deficiency in data on their taxonomic status, which is an impediment to their conservation. This would reduce ambiguity and underestimation of threats involved in assessing species complexes, and place the appropriate emphasis on the importance of taxonomy in anchoring conservation.Deutscher Akademischer Austauschdienst fellowshipDeutsche Forschungsgemeinschaft (VE247/13-1 and 15-1
Zurich Consensus: Statement of German Experts on St. Gallen Conference 2011 on Primary Breast Cancer (Zurich 2011)
Every 2 years, the International Consensus Conference on the Treatment of Primary Breast Cancer takes place in St. Gallen. Given that the concept of the St. Gallen Consensus Conference mainly reflects an international opinion, it appears useful to adapt the results of the vote for everyday therapy in Germany. A German working group comprising 28 breast cancer experts, amongst whom there are 3 members of the international St. Gallen panel, has therefore commented on this year's St. Gallen Consensus Conference (2011) from the German viewpoint. The focus of interest of this year's St. Gallen Conference was tumour biology as the starting point for decisions regarding individual therapy. There was an intensive discussion in relation to the clinical relevance of predictive and prognostic factors and possible consequences for decisions regarding therapy. Therefore, questions concerning the indication for adjuvant chemotherapy focused especially on the significance of the molecular phenotype of the tumour. In addition, important points for discussion were also the value of complete axillary dissection and the use of accelerated complete breast irradiation
An integrative taxonomic revision and redefinition of Gephyromantis (Laurentomantis) malagasius based on archival DNA analysis reveals four new mantellid frog species from Madagascar
The subgenus Laurentomantis in the genus Gephyromantis contains some of the least known amphibian species of Madagascar. The six currently valid nominal species are rainforest frogs known from few individuals, hampering a full understanding of the species diversity of the clade. We assembled data on specimens collected during field surveys over the past 30 years and integrated analysis of mitochondrial and nuclear-encoded genes of 88 individuals, a comprehensive bioacoustic analysis, and morphological comparisons to delimit a minimum of nine species-level lineages in the subgenus. To clarify the identity of the species Gephyromantis malagasius, we applied a target-enrichment approach to a sample of the 110 year-old holotype of Microphryne malagasia Methuen and Hewitt, 1913 to assign this specimen to a lineage based on a mitochondrial DNA barcode. The holotype clustered unambiguously with specimens previously named G. ventrimaculatus. Consequently we propose to consider Trachymantis malagasia ventrimaculatus Angel, 1935 as a junior synonym of Gephyromantis malagasius. Due to this redefinition of G. malagasius, no scientific name is available for any of the four deep lineages of frogs previously subsumed under this name, all characterized by red color ventrally on the hindlimbs. These are here formally named as Gephyromantis fiharimpe sp. nov., G. matsilo sp. nov., G. oelkrugi sp. nov., and G. portonae sp. nov. The new species are distinguishable from each other by genetic divergences of >4% uncorrected pairwise distance in a fragment of the 16S rRNA marker and a combination of morphological and bioacoustic characters. Gephyromantis fiharimpe and G. matsilo occur, respectively, at mid-elevations and lower elevations along a wide stretch of Madagascar’s eastern rainforest band, while G. oelkrugi and G. portonae appear to be more range-restricted in parts of Madagascar’s North East and Northern Central East regions. Open taxonomic questions surround G. horridus, to which we here assign specimens from Montagne d’Ambre and the type locality Nosy Be; and G. ranjomavo, which contains genetically divergent populations from Marojejy, Tsaratanana, and Ampotsidy.info:eu-repo/semantics/publishedVersio
Phospho-proteomic analyses of B-Raf protein complexes reveal new regulatory principles
B-Raf represents a critical physiological regulator of the Ras/RAF/MEK/ERK-pathway and a pharmacological target of growing clinical relevance, in particular in oncology. To understand how B-Raf itself is regulated, we combined mass spectrometry with genetic approaches to map its interactome in MCF-10A cells as well as in B-Raf deficient murine embryonic fibroblasts (MEFs) and B-Raf/Raf-1 double deficient DT40 lymphoma cells complemented with wildtype or mutant B-Raf expression vectors. Using a multi-protease digestion approach, we identified a novel ubiquitination site and provide a detailed B-Raf phospho-map. Importantly, we identify two evolutionary conserved phosphorylation clusters around T401 and S419 in the B-Raf hinge region. SILAC labelling and genetic/biochemical follow-up revealed that these clusters are phosphorylated in the contexts of oncogenic Ras, sorafenib induced Raf dimerization and in the background of the V600E mutation. We further show that the vemurafenib sensitive phosphorylation of the T401 cluster occurs in trans within a Raf dimer. Substitution of the Ser/Thr-residues of this cluster by alanine residues enhances the transforming potential of B-Raf, indicating that these phosphorylation sites suppress its signaling output. Moreover, several B-Raf phosphorylation sites, including T401 and S419, are somatically mutated in tumors, further illustrating the importance of phosphorylation for the regulation of this kinase
Transforming growth factor-β activated kinase 1 (Tak1) is activated in hepatocellular carcinoma, mediates tumor progression, and predicts unfavorable outcome
Although knowledge on inflammatory signaling pathways driving cancer initiation and progression has been increasing, molecular mechanisms in hepatocarcinogenesis are still far from being completely understood. Hepatocyte-specific deletion of the MAPKKK Tak1 in mice recapitulates important steps of hepatocellular carcinoma (HCC) development, including the occurrence of cell death, steatohepatitis, dysplastic nodules, and HCCs. However, overactivation of Tak1 in mice upon deletion of its deubiquitinase Cyld also results in steatohepatitis and HCC development. To investigate Tak1 and Cyld in human HCCs, we created a tissue microarray to analyze their expression by immunohistochemistry in a large and well-characterized cohort of 871 HCCs of 561 patients. In the human liver and HCC, Tak1 is predominantly present as its isoform Tak1A and predominantly localizes to cell nuclei. Tak1 is upregulated in diethylnitrosamine-induced mouse HCCs as well as in human HCCs independent of etiology and is further induced in distant metastases. A high nuclear Tak1 expression is associated with short survival and vascular invasion. When we overexpressed Tak1A in Huh7 cells, we observed increased tumor cell migration, whereas overexpression of full-length Tak1 had no significant effect. A combined score of low Cyld and high Tak1 expression was an independent prognostic marker in a multivariate Cox regression model
How not to describe a species: lessons from a tangle of anacondas (Boidae: Eunectes Wagler, 1830)
A recent revision of the anacondas (Serpentes: Boidae: Eunectes), with the description of a new species of green anaconda, generated extensive publicity, but also provoked considerable controversy due to inadequacies of the evidence used and errors in nomenclature. We here use the case of this problematic publication to: (i) highlight common issues affecting species delimitations, especially an over-reliance on mitochondrial DNA data, and reiterate best practices; (ii) reanalyse the data available for anacondas to establish the true current state of knowledge and to highlight lines of further research; and (iii) analyse the nomenclatural history and status of the genus. While our analysis reveals significant morphological variation in both green and yellow anacondas, denser sampling and an analysis of informative nuclear markers are required for meaningful species delimitation in Eunectes. Tracing the history of name-bearing types establishes Trinidad as the type locality for Boa murina Linnaeus, 1758 and allows identification of the extant lectotype for the species. Finally, we emphasize the responsibility of both journals and authors to ensure that published taxonomic work meets the burden of evidence required to substantiate new species descriptions and that species are named in compliance with the rules of zoological nomenclature
The atypical kinase RIOK1 promotes tumor growth and invasive behavior
Despite being overexpressed in different tumor entities, RIO kinases are hardly characterized in mammalian cells. We investigated the role of these atypical kinases in different cancer cells. Using isogenic colon-, breast- and lung cancer cell lines, we demonstrate that knockdown of RIOK1, but not of RIOK2 or RIOK3, strongly impairs proliferation and invasiveness in conventional and 3D culture systems. Interestingly, these effects were mainly observed in RAS mutant cancer cells. In contrast, growth of RAS wildtype Caco-2 and Bcr-Abl-driven K562 cells is not affected by RIOK1 knockdown, suggesting a specific requirement for RIOK1 in the context of oncogenic RAS signaling. Furthermore, we show that RIOK1 activates NF-κB signaling and promotes cell cycle progression. Using proteomics, we identified the pro-invasive proteins Metadherin and Stathmin1 to be regulated by RIOK1. Additionally, we demonstrate that RIOK1 promotes lung colonization in vivo and that RIOK1 is overexpressed in different subtypes of human lung- and breast cancer. Altogether, our data suggest RIOK1 as a potential therapeutic target, especially in RAS-driven cancers
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