Molecular phylogeny of living xenarthrans and the impact of character and taxon sampling on the placental tree rooting

Extant xenarthrans (armadillos, anteaters and sloths) are among the most derived placental mammals ever evolved. South America was the cradle of their evolutionary history. During the Tertiary, xenarthrans experienced an extraordinary radiation, whereas South America remained isolated from other continents. The 13 living genera are relics of this earlier diversification and represent one of the four major clades of placental mammals. Sequences of the three independent protein-coding nuclear markers alpha2B adrenergic receptor (ADRA2B), breast cancer susceptibility (BRCA1), and von Willebrand Factor (VWF) were determined for 12 of the 13 living xenarthran genera. Comparative evolutionary dynamics of these nuclear exons using a likelihood framework revealed contrasting patterns of molecular evolution. All codon positions of BRCA1 were shown to evolve in a strikingly similar manner, and third codon positions appeared less saturated within placentals than those of ADRA2B and VWF. Maximum likelihood and Bayesian phylogenetic analyses of a 47 placental taxa data set rooted by three marsupial outgroups resolved the phylogeny of Xenarthra with some evidence for two radiation events in armadillos and provided a strongly supported picture of placental interordinal relationships. This topology was fully compatible with recent studies, dividing placentals into the Southern Hemisphere clades Afrotheria and Xenarthra and a monophyletic Northern Hemisphere clade (Boreoeutheria) composed of Laurasiatheria and Euarchontoglires. Partitioned likelihood statistical tests of the position of the root, under different character partition schemes, identified three almost equally likely hypotheses for early placental divergences: a basal Afrotheria, an Afrotheria + Xenarthra clade, or a basal Xenarthra (Epitheria hypothesis). We took advantage of the extensive sampling realized within Xenarthra to assess its impact on the location of the root on the placental tree. By resampling taxa within Xenarthra, the conservative Shimodaira-Hasegawa likelihood-based test of alternative topologies was shown to be sensitive to both character and taxon sampling.     

Microbial diversity in ikaite tufa columns: an alkaline,cold ecological niche in Greenland

Ikaite tufa columns from the Ikka Fjord in south-western Greenland constitute a natural, stable environment at low temperature and with a pH ranging from neutral at the exterior to very alkaline (pH 10.4) at the interior of the column. Phylogenetic analysis of culturable organisms revealed ten different isolates representing three of the major bacterial divisions. Nine of the isolates showed 94-99% similarity to known sequences, whereas one isolate displayed a low degree of similarity (less than 90%) to a Cyclobacterium species. Seven of the isolates were shown to be cold active alkaliphiles, whereas three isolates showed optimal growth at neutral pH. Phylogenetic analysis of DNA isolated directly from the ikaite material demonstrated the presence of a microbial flora more diverse than the culturable isolates. Whereas approximately half of the phylotypes showed 90-99% similarity to known meso- or thermophilic alkaliphiles, the rest of the sequences displayed less than 90% similarity when compared to known 16S rRNA gene sequences in databases. Thus, in the present paper, we demonstrate that ikaite columns that host a specialized macroscopic flora and fauna also contain a unique, cold active, alkaliphilic microflora.     

Characterization of T cell hybridomas raised against a glycopeptide containing the tumor-associated T antigen, (betaGal (1-3) alphaGalNAc-O/Ser)

T cell hybridomas were raised against the glycopeptide S⁷² (Core-1) containing the tumor-associated disaccharide Gal (1–3) GalNAc (Core-1) O-linked to serine at position 72 in the mouse hemoglobin derived decapeptide Hb (67–76). All hybridomas recognized the glycopeptide S⁷² (Core-1). Two of the selected hybridomas responded, however, much better to the S⁷² (Tn) glycopeptide containing the monosaccharide GalNAc O-linked to serine. In addition, one hybridoma cross-responded to the glycopeptide T⁷² (Core-1) having a threonine at position 72 instead of a serine. No cross-responses were found to other glycopeptides consisting of the same hemoglobin peptide with different glycans attached or to the unglycosylated peptides. The T cell receptor V and V usage was clearly diverse. The CDR3 regions demonstrated moreover a predominance of small polar amino acid side chains, and three hybridomas contained a common sequence motif. All the sequenced CDR3 regions contained furthermore a conserved proline-glycine motif. In conclusion, immunization with the disaccharide containing glycopeptides S⁷² (Core-1) created a heterogeneous population of glycopeptide specific T cells with the ability of cross-responding toward related glycopeptides.     

Acoustic rhinometry in dog and cat compared with a fluid-displacement method and magnetic resonance imaging.

An increasing number of studies have used acoustic rhinometry (AR) for study of pharmacological interventions on nasal cavity dimensions in dogs and cats, but there have been no attempts to validate AR in these species. This is done in the present study. We compared area-distance relationships of nasal cavities from five decapitated dogs (3.5-41 kg) and cats (3.8-6 kg). AR was compared with magnetic resonance (MR) imaging and a fluid-displacement method (FDM) using perfluorocarbon. AR measured 88% (98-79%) (mean and 95% confidence interval) of nasal cavity volume in dogs determined by FDM and 71% (83-59%) in cats. AR markedly underestimated nasal cavity dimensions when minimum areas were below 0.1 cm2 in dogs and 0.05 cm2 in cats. AR underestimation increased with the severity of the constriction and with distance. Cross-sectional areas in the deeper parts of the cavity measured 76% (99-54%) of FDM in dogs and 52% (66-39%) in cats. AR agreed well with MR, especially in the deeper part of the cavity. MR images showed that the nasal cavities had a very complex structure not expected to be reproduced by AR. MR could not be considered a "gold standard" because definition of the cross-sectional area of the lumen depended critically on subjective choices. FDM produced repeatable measurements and possibly offers the most adequate reference in future evaluation of AR. AR underestimated what we believed were the most correct cross-sectional areas determined by FDM, especially in the deeper part of the dog and cat nasal cavities. Despite these difficulties, AR has been shown to be useful to describe qualitative changes in cross-sectional area.     

Riboflavin-photosensitized changes in aqueous solutions of alginate. Rheological studies

Interactions between photoexcited riboflavin (RF), promoted by irradiation in the range of 310-800 nm, and alginate have been studied in air equilibrated aqueous solutions with the aid of rheological methods. Light irradiation of RF causes under aerobic conditions fragmentation of alginate and a decrease in the shear viscosity and other rheological parameters of its solutions. The decrease is most pronounced in concentrated polymer solutions. The photochemical degradation of alginate is inhibited in the presence of the quenchers/scavengers d-mannitol, glutathione, potassium iodide, and sodium azide and in excess oxygen. The addition of thiourea to alginate-RF solutions leads to enhanced degradation of the polymer. Significant shear-thinning effects and deviations from the Cox-Merz rule are observed at higher polymer concentrations.     

The 1st results in the realization of the Harm Reduction program for intravenous narcotic users in the city of Penza

To achieve the aims of the project, the following stages were consecutively defined: (1) the exchange of syringes, organized by outreach workers, with the simultaneous popularization of the project, (2) the orientation of intravenous drug users to attending syringe exchange stations and (3) the extension of the area covered by the activities of outreach workers. Our experience showed that outreach workers, especially those working in the street, were the main force to count on for achieving success in the work of the projects. The budget of the project should provide for the publication of information material. Special assignments for outreach workers to study some concrete problem (drug service, the use of blood, etc.) can be useful. It is expedient to raise the status of syringe exchange stations by turning them into multi-purpose consultation centers.     

Editing of Multidimensional NMR Spectra of Partially Deuterated Proteins. Measurement of Amide Deuterium Isotope Effects on the Chemical Shifts of Protein Backbone Nuclei

Novel multidimensional NMR pulse sequences are presented for determination of amide deuterium isotope effects on the 13C chemical shifts of the backbone in proteins. The sequences edit heteronuclear triple resonance spectra into two subspectra according to whether a deuterium or a proton is attached to 15N for the pertinent correlations. The new experiments are demonstrated using 13C, 15N-labeled RAP 17-112 (N-terminal domain of 2-macroglobulin receptor associated protein).