The Wilms tumor genes wt1a and wt1b control different steps during formation of the zebrafish pronephros

The Wilms tumor protein WT1 is an essential factor for kidney development. In humans, mutations in WT1 lead to Wilms tumor, a pediatric kidney cancer as well as to developmental anomalies concerning the urogenital tract. Inactivation of Wt1 in mice causes multiple organ defects most notably agenesis of the kidneys. In zebrafish, two paralogous wt1 genes exist, wt1a and wt1b. The wt1 genes are expressed in a similar and overlapping but not identical pattern. Here, we have examined the role of both wt1 genes in early kidney development employing a transgenic line with pronephros specific GFP expression and morpholino knockdown experiments. Inactivation of wt1a led to failure of glomerular differentiation and morphogenesis resulting in a rapidly expanding general body edema. In contrast, knockdown of wt1b was compatible with early glomerular development. After 48 h, however, wt1b morphant embryos developed cysts in the region of the glomeruli and tubules and subsequent pericardial edema at 4 days post-fertilization. Thus, our data suggest different functions for wt1a and wt1b in zebrafish nephrogenesis. While wt1a has a more fundamental and early role in pronephros development and is essential for the formation of glomerular structures, wt1b functions at later stages of nephrogenesis.     

An improved molecular phylogeny of the Nematoda with special emphasis on marine taxa

Phylogenetic reconstructions of relations within the phylum Nematoda are inherently difficult but have been advanced with the introduction of large-scale molecular-based techniques. However, the most recent revisions were heavily biased towards terrestrial and parasitic species and greater representation of clades containing marine species (e.g. Araeolaimida, Chromadorida, Desmodorida, Desmoscolecida, Enoplida, and Monhysterida) is needed for accurate coverage of known taxonomic diversity. We now add small subunit ribosomal DNA (SSU rDNA) sequences for 100 previously un-sequenced species of nematodes, including 46 marine taxa. SSU rDNA sequences for >200 taxa have been analysed based on Bayesian inference and LogDet-transformed distances. The resulting phylogenies provide support for (i) the re-classification of the Secernentea as the order Rhabditida that derived from a common ancestor of chromadorean orders Araeolaimida, Chromadorida, Desmodorida, Desmoscolecida, and Monhysterida and (ii) the position of Bunonema close to the Diplogasteroidea in the Rhabditina. Other, previously controversial relationships can now be resolved more clearly: (a) Alaimus, Campydora, and Trischistoma belong in the Enoplida, (b) Isolaimium is placed basally to a big clade containing the Axonolaimidae, Plectidae, and Rhabditida, (c) Xyzzors belongs in the Desmodoridae, (d) Comesomatidae and Cyartonema belongs in the Monhysterida, (e) Globodera belongs in the Hoplolaimidae and (f) Paratylenchus dianeae belongs in the Criconematoidea. However, the SSU gene did not provide significant support for the class Chromadoria or clear evidence for the relationship between the three classes, Enoplia, Dorylaimia, and Chromadoria. Furthermore, across the whole phylum, the phylogenetically informative characters of the SSU gene are not informative in a parsimony analysis, highlighting the short-comings of the parsimony method for large-scale phylogenetic modelling.     

Incongruent plastid and nuclear DNA phylogenies reveal ancient intergeneric hybridization in Pilosella hawkweeds (Hieracium, Cichorieae, Asteraceae)

Phylogenetic relationships for Hieracium subgen. Pilosella were inferred from chloroplast (trnT-trnL, matK) and nuclear (ITS) sequence data. Chloroplast markers revealed the existence of two divergent haplotype groups within the subgenus that did not correspond to presumed relationships. Furthermore, chloroplast haplotypes of the genera Hispidella and Andryala nested each within one of these groups. In contrast, ITS data were generally in accord with morphology and other evidence and were therefore assumed to reflect the true phylogeny. They revealed a sister relationship between Pilosella and Hispidella and a joint clade of Hieracium subgenera Hieracium and Chionoracium (Stenotheca) while genus Andryala represented a third major lineage of the final ingroup cluster. Detailed analysis of trnT-trnL character state evolution along the ITS tree suggested two intergeneric hybridization events between ancestral lineages that resulted in cytoplasmic transfer (from Hieracium/Chionoracium to Pilosella, and from the introgressed Pilosella lineage to Andryala). These chloroplast capture events, the first of which involved a now extinct haplotype, are the most likely explanation for the observed incongruencies between plastid and nuclear DNA markers.     

A novel, single nucleotide polymorphism-based assay to detect 22q11 deletions

Velocardiofacial syndrome, DiGeorge syndrome, and conotruncal anomaly face syndrome, now collectively referred to as 22q11deletion syndrome (22q11DS) are caused by microdeletions on chromosome 22q11. The great majority ( approximately 90%) of these deletions are 3 Mb in size. The remaining deleted patients have nested break-points resulting in overlapping regions of hemizygosity. Diagnostic testing for the disorder is traditionally done by fluorescent in situ hybridization (FISH) using probes located in the proximal half of the region common to all deletions. We developed a novel, high-resolution single-nucleotide polymorphism (SNP) genotyping assay to detect 22q11 deletions. We validated this assay using DNA from 110 nondeleted controls and 77 patients with 22q11DS that had previously been tested by FISH. The assay was 100% sensitive (all deletions were correctly identified). Our assay was also able to detect a case of segmental uniparental disomy at 22q11 that was not detected by the FISH assay. We used Bayesian networks to identify a set of 17 SNPs that are sufficient to ascertain unambiguously the deletion status of 22q11DS patients. Our SNP based assay is a highly accurate, sensitive, and specific method for the diagnosis of 22q11 deletion syndrome.     

Invasive Fungal Infection Caused by Exophiala dermatitidis in a Patient After Lung Transplantation: Case Report and Literature Review

Mycopathologia - This report describes a case of invasive Exophiala dermatitidis infection after double lung transplantation in a 76-year-old man. After thoracotomy, the patient’s wound...     

HPTLC Autography Based Screening and Isolation of Mushroom Tyrosinase Inhibitors of European Plant Species

In the course of this project, 133 plants were evaluated on their ability to inhibit tyrosinase, a key enzyme in melanogenesis. The screening was performed by means of a HPTLC autographic assay, resulting in the selection of three plants, Asplenium trichomanes, Pinus uncinata, and Scutellaria altissima, with promising tyrosinase inhibiting activities. With the aid of the HPTLC assay, it was not only possible to select the most interesting plant extracts, but also to monitor the activity‐guided fractionation which, in a relatively short time period, led to the isolation of active principles. Benzoic acid, roseoside, and dihydrovomifoliol‐O‐β‐d ‐glucopyranoside could be identified as tyrosinase inhibitors present in P. uncinata. Globularin turned out to be the active principle of S. altissima, and 4‐ethenylphenyl 6‐O‐(6‐deoxy‐α‐l ‐mannopyranosyl)‐β‐d ‐glucopyranoside was detected as tyrosinase inhibitor of A. trichomanes. The pure compounds were tested also in a 96 well‐plate assay in order to determine their IC₅₀ values. The lowest IC₅₀ value (42 μm ) could be obtained for globularin, whereas the other compounds, e. g., benzoic acid exhibited a rather high IC₅₀ value (IC₅₀=552 μm ). This stood in clear contrast to the autographic assay, but is has to be taken into account that the outcome of the autography assay is not only depending on the IC50 value of a compound, but also on the content of the respective constituent in the extract.