Phylogenomics of the dog and fox family (Canidae,Carnivora) revealed by chromosome painting

Canid species (dogs and foxes) have highly rearranged karyotypes and thus represent a challenge for conventional comparative cytogenetic studies. Among them, the domestic dog is one of the best-mapped species in mammals, constituting an ideal reference genome for comparative genomic study. Here we report the results of genome-wide comparative mapping of dog chromosome-specific probes onto chromosomes of the dhole, fennec fox, and gray fox, as well as the mapping of red fox chromosome-specific probes onto chromosomes of the corsac fox. We also present an integrated comparative chromosome map between the species studied here and all canids studied previously. The integrated map demonstrates an extensive conservation of whole chromosome arms across different canid species. In addition, we have generated a comprehensive genome phylogeny for the Canidae on the basis of the chromosome rearrangements revealed by comparative painting. This genome phylogeny has provided new insights into the karyotypic relationships among the canids. Our results, together with published data, allow the formulation of a likely Canidae ancestral karyotype (CAK, 2n = 82), and reveal that at least 6–24 chromosomal fission/fusion events are needed to convert the CAK karyotype to that of the modern canids. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Chromosomal evolution of Arvicolinae (Cricetidae, Rodentia). II. The genome homology of two mole voles (genus Ellobius), the field vole and golden hamster revealed by comparative chromosome painting

Using cross-species chromosome painting, we have carried out a comprehensive comparison of the karyotypes of two Ellobius species with unusual sex determination systems: the Transcaucasian mole vole, Ellobius lutescens (2n = 17, X in both sexes), and the northern mole vole, Ellobius talpinus (2n = 54, XX in both sexes). Both Ellobius species have highly rearranged karyotypes. The chromosomal paints from the field vole (Microtus agrestis) detected, in total, 34 and 32 homologous autosomal regions in E. lutescens and E. talpinus karyotypes, respectively. No difference in hybridization pattern of the X paint (as well as Y paint) probes on male and female chromosomes was discovered. The set of golden hamster (Mesocricetus auratus) chromosomal painting probes revealed 44 and 43 homologous autosomal regions in E. lutescens and E. talpinus karyotypes, respectively. A comparative chromosome map was established based on the results of cross-species chromosome painting and a hypothetical ancestral Ellobius karyotype was reconstructed. A considerable number of rearrangements were detected; 31 and 7 fusion/fission rearrangements differentiated the karyotypes of E. lutescens and E. talpinus from the ancestral Ellobius karyotype. It seems that inversions have played a minor role in the genome evolution of these Ellobius species.     

Fibrinogen adsorption by PS latex particles coated with various amounts of a PEO/PPO/PEO triblock copolymer

Polystyrene (PS) latex particles of different sizes were adsorption coated with the polymeric surfactant Pluronic F108 (PEO129-PPO56-PEO129). The commercial surfactant was found to have a bimodal molecular weight distribution. However, the maximum surface concentrations resulting from adsorption of either the purified high molecular weight component or the composite were identical. An increase in the copolymer surface concentration on 252-nm particles was found to decrease their fibrinogen uptake exponentially. At maximum copolymer surface concentration, the fibrinogen uptake was two orders of magnitude lower than that of bare particles (down from 3.3 mg/m2 to 0.03 mg/m2). This surface protection was equally effective whether the adsorption involved the bimodal polymer surfactant or the purified high molecular weight fraction. The PEO tail mobility was investigated with electron paramagnetic resonance (EPR), and found to increase with an increase in polymer surface concentration. The comparatively slow motion of the PEO chains at low surface concentration indicated that not only the PPO block, but also the PEO blocks interacted hydrophobically with the PS surface. When the copolymer surface concentration was increased, the PEO tails were gradually being released, acquiring higher mobility as the surface became covered by the more strongly binding PPO blocks. Results obtained with F108 coated particles of different sizes showed that particle size had a significant effect on the fibrinogen uptake, with larger particles showing larger fibrinogen uptakes.     

Molecular-genetic diagnostics of von Hippel-Lindau syndrome (VHL) in Bulgaria: first complex mutation event in the VHL gene

Von Hippel-Lindau syndrome is an autosomal-dominant disease characterized by the formation of various tumours and cysts in many different parts of the body. Von Hippel-Lindau syndrome is caused by VHL gene mutations leading to production of impaired tumor suppressor Von Hippel-Lindau syndrome protein or its complete absence. Purpose: To study five patients with clinically suspected Von Hippel-Lindau syndrome, who were referred for molecular genetic testing. Methods: Sanger sequencing of the coding regions of the VHL gene. Results: Five clinically relevant germline mutations were detected. One of the pathogenic variants has not been previously reported. This novel mutation is a complex mutation event combining a duplication and an indel, rearranging exon 3 of the VHL gene - c. [516_517dupGTCAAGCCT; 532_542delCTGGACATCGTinsATTA], p. (Glu173Serfs*4). Conclusion: Overall, our results showed that the diagnosis of Von Hippel-Lindau syndrome in our country is difficult most probably because of its heterogeneous clinical manifestation and insufficient knowledge on the diagnostic criteria for the disease. From genetic point of view our results add some novel data on the mutation profile of the VHL gene. In order to prove or revise the diagnosis, early genetic testing is strongly recommended in affected patients and their family members to ensure appropriate follow-up and treatment of the malignancies.     

Reduced number of satellite oligodendrocytes of pyramidal neurons in layer 5 of the prefrontal cortex in schizophrenia

European Archives of Psychiatry and Clinical Neuroscience - Neuroimaging, genetic and molecular biological studies have shown impaired intra-cortical myelination in patients with schizophrenia,...     

Expression of factor VIII in recombinant and transgenic systems

Deficiency in a coagulation factor VIII (FVIII) causes a genetic disorder hemophilia A, which is treated by repeated infusions of expensive FVIII products. Recombinant FVIII (rFVIII), the culmination of years of extensive international research, is an important alternative to plasma-derived FVIII (pdFVIII) and is considered to have a higher margin of safety. Advances in biotechnology allowed production of rFVIII at industrial scale, which significantly improved treatment of hemophilia A patients. We review the contemporary methods used for FVIII expression in mammalian cell culture systems and discuss the factors responsible for insufficient recoveries of rFVIII, such as inefficient accumulation of FVIII mRNA in the cell, complexity of the mechanisms of FVIII secretion, and instability of secreted FVIII. The approaches to improve the yield of rFVIII in cell culture systems include genetic engineering of B-domain-deleted FVIII, introduction of introns into FVIII cDNA constructs for more efficient processing and accumulation of FVIII mRNA, and introduction of mutations into chaperone-binding sites of FVIII to improve its secretion. Design of FVIII with prolonged half-life in vivo is considered as another promising direction in improving rFVIII protein and efficiency of hemophilia A therapy. As an alternative to expression of rFVIII in cell culture systems, we discuss production of rFVIII in transgenic animals, where high levels of rFVIII have been successfully secreted into milk. We also pay attention to the major limitations of this approach, such as safety issues associated with potential transmission of animal pathogens. Finally, we present a brief characterization of commercial recombinant FVIII products currently available on the market for hemophilia A treatment.     

Using the wisdom of the crowds to find critical errors in biomedical ontologies: a study of SNOMED CT

Objectives The verification of biomedical ontologies is an arduous process that typically involves peer review by subject-matter experts. This work evaluated the ability of crowdsourcing methods to detect errors in SNOMED CT (Systematized Nomenclature of Medicine Clinical Terms) and to address the challenges of scalable ontology verification.Methods We developed a methodology to crowdsource ontology verification that uses micro-tasking combined with a Bayesian classifier. We then conducted a prospective study in which both the crowd and domain experts verified a subset of SNOMED CT comprising 200 taxonomic relationships.Results The crowd identified errors as well as any single expert at about one-quarter of the cost. The inter-rater agreement (κ) between the crowd and the experts was 0.58; the inter-rater agreement between experts themselves was 0.59, suggesting that the crowd is nearly indistinguishable from any one expert. Furthermore, the crowd identified 39 previously undiscovered, critical errors in SNOMED CT (eg, ‘septic shock is a soft-tissue infection’).Discussion The results show that the crowd can indeed identify errors in SNOMED CT that experts also find, and the results suggest that our method will likely perform well on similar ontologies. The crowd may be particularly useful in situations where an expert is unavailable, budget is limited, or an ontology is too large for manual error checking. Finally, our results suggest that the online anonymous crowd could successfully complete other domain-specific tasks.Conclusions We have demonstrated that the crowd can address the challenges of scalable ontology verification, completing not only intuitive, common-sense tasks, but also expert-level, knowledge-intensive tasks.