The brown hare (Lepus europaeus) as a novel intermediate host for Echinococcus multilocularis in Europe

A typical multivesiculated metacestode tissue has been found in the liver of a European brown hare (Lepus europaeus) originating from a northern area of Switzerland. In this study, the causative species was identified as Echinococcus multilocularis by appropriate histological and molecular analyses and corresponding DNA sequencing. This is the first confirmation of larval E. multilocularis from hares in central Europe. The metacestode tissue contained protoscolices, suggesting that the hare may contribute to the transmission of E. multilocularis in Switzerland.

The gene for histone RNA hairpin binding protein is located on human chromosome 4 and encodes a novel type of RNA binding protein.

The hairpin structure at the 3' end of animal histone mRNAs controls histone RNA 3' processing, nucleocytoplasmic transport, translation and stability of histone mRNA. Functionally overlapping, if not identical, proteins binding to the histone RNA hairpin have been identified in nuclear and polysomal extracts. Our own results indicated that these hairpin binding proteins (HBPs) bind their target RNA as monomers and that the resulting ribonucleoprotein complexes are extremely stable. These features prompted us to select for HBP-encoding human cDNAs by RNA-mediated three-hybrid selection in Saccharomyces cerevesiae. Whole cell extract from one selected clone contained a Gal4 fusion protein that interacted with histone hairpin RNA in a sequence- and structure-specific manner similar to a fraction enriched for bovine HBP, indicating that the cDNA encoded HBP. DNA sequence analysis revealed that the coding sequence did not contain any known RNA binding motifs. The HBP gene is composed of eight exons covering 19.5 kb on the short arm of chromosome 4. Translation of the HBP open reading frame in vitro produced a 43 kDa protein with RNA binding specificity identical to murine or bovine HBP. In addition, recombinant HBP expressed in S. cerevisiae was functional in histone pre-mRNA processing, confirming that we have indeed identified the human HBP gene.

Chromosomally and extrachromosomally mediated high-level gentamicin resistance in Streptococcus agalactiae

Streptococcus agalactiae (group B Streptococcus, GBS) is a leading cause of sepsis in neonates. The rate of invasive GBS disease in non-pregnant adults also continues to climb. Aminoglycosides alone have little or no effect on GBS, but synergistic killing with penicillin has been shown in vitro. High-level gentamicin resistance (HLGR) in GBS isolates, however, leads to loss of a synergistic effect. We therefore performed a multicentre study to determine the frequency of HLGR GBS isolates and to elucidate the molecular mechanisms leading to gentamicin resistance. From eight centres in four countries, 1128 invasive and colonizing GBS isolates were pooled and investigated for the presence of HLGR. We identified two strains that displayed HLGR (BSU1203 and BSU452), both of which carried the aacA-aphD gene, typically conferring HLGR. Though, only one strain (BSU1203) also carried the previously described chromosomal gentamicin resistance transposon, designated Tn3706. In the other strain (BSU452), plasmid purification and subsequent DNA sequencing resulted in the detection of plasmid pIP501 carrying a remnant of a Tn3 family transposon. Its ability to confer HLGR was proven by transfer into an Enterococcus faecalis isolate. Conversely, loss of HLGR was documented after curing both GBS BSU452 and the transformed E. faecalis strain from the plasmid. This is the first report showing a plasmid mediated HLGR in GBS. Thus, in our clinical GBS isolates HLGR is mediated both chromosomally and extrachromosomally.

The Phosphoinositide 3-Kinase p110α Isoform Regulates Leukemia Inhibitory Factor Receptor Expression via c-Myc and miR-125b to Promote Cell Proliferation in Medulloblastoma.

Medulloblastoma (MB) is the most common malignant brain tumor in childhood and represents the main cause of cancer-related death in this age group. The phosphoinositide 3-kinase (PI3K) pathway has been shown to play an important role in the regulation of medulloblastoma cell survival and proliferation, but the molecular mechanisms and downstream effectors underlying PI3K signaling still remain elusive. The impact of RNA interference (RNAi)-mediated silencing of PI3K isoforms p110α and p110δ on global gene expression was investigated by DNA microarray analysis in medulloblastoma cell lines. A subset of genes with selectively altered expression upon p110α silencing in comparison to silencing of the closely related p110δ isoform was revealed. Among these genes, the leukemia inhibitory factor receptor α (LIFR α) was validated as a novel p110α target in medulloblastoma. A network involving c-Myc and miR-125b was shown to be involved in the control of LIFRα expression downstream of p110α. Targeting the LIFRα by RNAi, or by using neutralizing reagents impaired medulloblastoma cell proliferation in vitro and induced a tumor volume reduction in vivo. An analysis of primary tumors revealed that LIFRα and p110α expression were elevated in the sonic hedgehog (SHH) subgroup of medulloblastoma, indicating its clinical relevance. Together, these data reveal a novel molecular signaling network, in which PI3K isoform p110α controls the expression of LIFRα via c-Myc and miR-125b to promote MB cell proliferation.

Genomics of Rapid Incipient Speciation in Sympatric Threespine Stickleback

Ecological speciation is the process by which reproductively isolated populations emerge as a consequence of divergent natural or ecologically-mediated sexual selection. Most genomic studies of ecological speciation have investigated allopatric populations, making it difficult to infer reproductive isolation. The few studies on sympatric ecotypes have focused on advanced stages of the speciation process after thousands of generations of divergence. As a consequence, we still do not know what genomic signatures of the early onset of ecological speciation look like. Here, we examined genomic differentiation among migratory lake and resident stream ecotypes of threespine stickleback reproducing in sympatry in one stream, and in parapatry in another stream. Importantly, these ecotypes started diverging less than 150 years ago. We obtained 34,756 SNPs with restriction-site associated DNA sequencing and identified genomic islands of differentiation using a Hidden Markov Model approach. Consistent with incipient ecological speciation, we found significant genomic differentiation between ecotypes both in sympatry and parapatry. Of 19 islands of differentiation resisting gene flow in sympatry, all were also differentiated in parapatry and were thus likely driven by divergent selection among habitats. These islands clustered in quantitative trait loci controlling divergent traits among the ecotypes, many of them concentrated in one region with low to intermediate recombination. Our findings suggest that adaptive genomic differentiation at many genetic loci can arise and persist in sympatry at the very early stage of ecotype divergence, and that the genomic architecture of adaptation may facilitate this.

Initial characterization of stiff skin-like syndrome in West Highland white terriers

BACKGROUND Stiff skin syndrome and systemic or localized scleroderma are cutaneous disorders characterized by dermal fibrosis and present clinically with induration of the skin, with or without joint, internal organ or vascular involvement. OBJECTIVES To provide clinical, histological and preliminary genetic analysis of two West Highland white terrier siblings presenting with indurated skin resembling stiff skin syndrome in humans. ANIMALS Two client owned full sibling West Highland white terriers from two different litters. METHODS Clinical examination, histopathological examination and whole genome sequencing analysis of affected and unaffected West Highland white terriers. RESULTS Affected dogs exhibited markedly indurated skin that was attached firmly to the underlying tissue and incomplete closure of the mouth and eyes. No abnormalities were found by neurological or orthopaedic examination, radiographs of the head or whole body computed tomography. Histologically, the dermis and pannicular septa were thickened by a marked increase in coarse collagen fibres and a mild to moderate increase in collagen fibre diameter. The syndrome most likely follows an autosomal recessive mode of inheritance. The sequence analysis did not reveal any obvious causative variant in the investigated candidate genes ADAMTSL2 and FBN1. CONCLUSION AND CLINICAL IMPORTANCE The clinical phenotype and histopathological features of two West Highland white terrier siblings resembled stiff skin syndrome in humans. Unlike in humans, or previously described beagles with stiff skin, there was no restriction of joint mobility. Genetic analysis did not detect a candidate causative variant and warrants further research.

Prediction of whole-genome DNA-DNA similarity, determination of G+C content and phylogenetic analysis within the family Pasteurellaceae by multilocus sequence analysis (MLSA)

Genome predictions based on selected genes would be a very welcome approach for taxonomic studies, including DNA-DNA similarity, G+C content and representative phylogeny of bacteria. At present, DNA-DNA hybridizations are still considered the gold standard in species descriptions. However, this method is time-consuming and troublesome, and datasets can vary significantly between experiments as well as between laboratories. For the same reasons, full matrix hybridizations are rarely performed, weakening the significance of the results obtained. The authors established a universal sequencing approach for the three genes recN, rpoA and thdF for the Pasteurellaceae, and determined if the sequences could be used for predicting DNA-DNA relatedness within the family. The sequence-based similarity values calculated using a previously published formula proved most useful for species and genus separation, indicating that this method provides better resolution and no experimental variation compared to hybridization. By this method, cross-comparisons within the family over species and genus borders easily become possible. The three genes also serve as an indicator of the genome G+C content of a species. A mean divergence of around 1 % was observed from the classical method, which in itself has poor reproducibility. Finally, the three genes can be used alone or in combination with already-established 16S rRNA, rpoB and infB gene-sequencing strategies in a multisequence-based phylogeny for the family Pasteurellaceae. It is proposed to use the three sequences as a taxonomic tool, replacing DNA-DNA hybridization.