University of Cologne

About: University of Cologne is a education organization based out in Cologne, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 32050 authors who have published 66350 publications receiving 2210092 citations. The organization is also known as: Universität zu Köln & Universitatis Coloniensis.

Deciphering amphibian diversity through DNA barcoding: chances and challenges

Abstract: Amphibians globally are in decline, yet there is still a tremendous amount of unrecognized diversity, calling for an acceleration of taxonomic exploration. This process will be greatly facilitated by a DNA barcoding system; however, the mitochondrial population structure of many amphibian species presents numerous challenges to such a standardized, single locus, approach. Here we analyse intraand interspecific patterns of mitochondrial variation in two distantly related groups of amphibians, mantellid frogs and salamanders, to determine the promise of DNA barcoding with cytochrome oxidase subunit I (cox1) sequences in this taxon. High intraspecific cox1 divergences of 7‐14% were observed (18% in one case) within the whole set of amphibian sequences analysed. These high values are not caused by particularly high substitution rates of this gene but by generally deep mitochondrial divergences within and among amphibian species. Despite these high divergences, cox1 sequences were able to correctly identify species including disparate geographic variants. The main problems with cox1 barcoding of amphibians are (i) the high variability of priming sites that hinder the application of universal primers to all species and (ii) the observed distinct overlap of intraspecific and interspecific divergence values, which implies difficulties in the definition of threshold values to identify candidate species. Common discordances between geographical signatures of mitochondrial and nuclear markers in amphibians indicate that a single-locus approach can be problematic when high accuracy of DNA barcoding is required. We suggest that a number of mitochondrial and nuclear genes may be used as DNA barcoding markers to complement cox1.

First-line chemoimmunotherapy with bendamustine and rituximab versus fludarabine, cyclophosphamide, and rituximab in patients with advanced chronic lymphocytic leukaemia (CLL10): an international, open-label, randomised, phase 3, non-inferiority trial.

Abstract: Summary Background Chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab is the standard therapy for physically fit patients with advanced chronic lymphocytic leukaemia. This international phase 3 study compared the efficacy and tolerance of the standard therapy with a potentially less toxic combination consisting of bendamustine and rituximab. Methods Treatment-naive fit patients with chronic lymphocytic leukaemia (aged 33–81 years) without del(17p) were enrolled after undergoing a central screening process. Patients were randomly assigned (1:1) with a computer-generated randomisation list using randomly permuted blocks with a block size of eight and were stratified according to participating country and Binet stage. Patients were allocated to receive six cycles of intravenous fludarabine (25 mg/m 2 per day) and cyclophosphamide (250 mg/m 2 per day) for the first 3 days or to intravenous bendamustine (90 mg/m 2 per day) for the first 2 days of each cycle. Rituximab 375 mg/m 2 was given intravenously in both groups on day 0 of cycle 1 and subsequently was given at 500 mg/m 2 during the next five cycles on day 1. The primary endpoint was progression-free survival with the objective to assess non-inferiority of bendamustine and rituximab to the standard therapy. We aimed to show that the 2-year progression-free survival with bendamustine and rituximab was not 67·5% or less with a corresponding non-inferiority margin of 1·388 for the hazard ratio (HR) based on the 90·4% CI. The final analysis was done by intention to treat. The study is registered with ClinicalTrials.gov, number NCT%2000769522. Findings 688 patients were recruited between Oct 2, 2008, and July 11, 2011, of which 564 patients who met inclusion criteria were randomly assigned. 561 patients were included in the intention-to-treat population: 282 patients in the fludarabine, cyclophosphamide, and rituximab group and 279 in the bendamustine and rituximab group. After a median observation time of 37·1 months (IQR 31·0–45·5) median progression-free survival was 41·7 months (95% CI 34·9–45·3) with bendamustine and rituximab and 55·2 months (95% CI not evaluable) with fludarabine, cyclophosphamide, and rituximab (HR 1·643, 90·4% CI 1·308–2·064). As the upper limit of the 90·4% CI was greater than 1·388 the null hypothesis for the corresponding non-inferiority hypothesis was not rejected. Severe neutropenia and infections were more frequently observed with fludarabine, cyclophosphamide, and rituximab (235 [84%] of 279 vs 164 [59%] of 278, and 109 [39%] vs 69 [25%], respectively) during the study. The increased frequency of infectious complications with fludarabine, cyclophosphamide, and rituximab was more pronounced in patients older than 65 years. Interpretation The combination of fludarabine, cyclophosphamide, and rituximab remains the standard front-line therapy in fit patients with chronic lymphocytic leukaemia, but bendamustine and rituximab is associated with less toxic effects. Funding Roche Pharma AG, Mundipharma, German Federal Ministry of Education and Research.

TRIPTYCHON and CAPRICE mediate lateral inhibition during trichome and root hair patterning in Arabidopsis

Abstract: Trichome patterning in Arabidopsis is a model for the generation of a spacing pattern from initially equivalent cells. We show that the TRIPTYCHON gene that functions in lateral inhibition encodes a single-repeat MYB-related transcription factor that lacks a recognizable activation domain. It has high sequence similarity to the root hair patterning gene CAPRICE. Both genes are expressed in trichomes and act together during lateral inhibition. We further show that TRIPTYCHON and CAPRICE act redundantly in the position-dependent cell fate determination in the root epidermis. Thus, the same lateral inhibition mechanism seems to be involved in both de novo patterning and position-dependent cell determination. We propose a model explaining trichome and root hair patterning by a common mechanism.