Metrik und Evolutionsniveau der Höhlenbärenzähne aus der Medvedia-Höhle im Slovensky raj (Slowakei)

Während der dreijähriger Grabungskampagne in einer Forschungskooperation zwischen der Universität Wien (Institut für Paläontologie) und der Comenius-Universität (Die Abteilung der Geologie und Paläontologie) Bratislava, wurden in der Bären-Höhle Medvedia jaskyna, die im Nationalpark Slovenský raj liegt, eine große Zahl an Bärenresten geborgen. Für die vorliegende Studie standen insgesamt 1016 Zahnelemente (148 Eckzähne sowie 868 Backenzähne) von Höhlenbären zur Verfügung. Durch metrische und morphodynamische Analysen, sowie durch Vergleiche mit anderen Höhlenbärenfaunen konnte die systematische Stellung der Bären geklärt werden. Alle untersuchten Reste gehören einem großwüchsigen, hoch evoluierten Höhlenbären an, der erst vor ca. 50.000 Jahren nach Mitteleuropa eingewandert ist. Aus der metrischen Verteilung der Eckzähne kann geschlossen werden, dass das Geschlechtsverhältnis ausgeglichen war

Assembling of G-strands into novel tetra-molecular parallel G4-DNA nanostructures using avidin–biotin recognition

We describe a method for the preparation of novel long (hundreds of nanometers), uniform, inter-molecular G4-DNA molecules composed of four parallel G-strands. The only long continuous G4-DNA reported so far are intra-molecular structures made of a single G-strand. To enable a tetra-molecular assembly of the G-strands we developed a novel approach based on avidin–biotin biological recognition. The steps of the G4-DNA production include: (i) Enzymatic synthesis of long poly(dG)-poly(dC) molecules with biotinylated poly(dG)-strand; (ii) Formation of a complex between avidin-tetramer and four biotinylated poly(dG)-poly(dC) molecules; (iii) Separation of the poly(dC) strands from the poly(dG)-strands, which are connected to the avidin; (iv) Assembly of the four G-strands attached to the avidin into tetra-molecular G4-DNA. The average contour length of the formed structures, as measured by AFM, is equal to that of the initial poly(dG)-poly(dC) molecules, suggesting a tetra-molecular mechanism of the G-strands assembly. The height of tetra-molecular G4-nanostructures is larger than that of mono-molecular G4-DNA molecules having similar contour length. The CD spectra of the tetra- and mono-molecular G4-DNA are markedly different, suggesting different structural organization of these two types of molecules. The tetra-molecular G4-DNA nanostructures showed clear electrical polarizability. This suggests that they may be useful for molecular electronics

Risk of Dumping Syndrome after Sleeve Gastrectomy and Roux-en-Y Gastric Bypass: Early Results of a Multicentre Prospective Study

Background. Bariatric surgery is an important field of surgery. An important complication of bariatric surgery is dumping syndrome (DS). Aims. To evaluate the incidence of DS in patients undergoing bariatric surgery. Methods. 541 patients included from 5 nutrition and bariatric centers in France underwent either LSG or LRYGB. They were evaluated at 1 month (M1) and 6 months (M6) postoperatively by an interview and completion of a dumping syndrome questionnaire. Results. 268 patients underwent LSG (Group A) and 273 underwent LRYGB. From the LRYGB patients 229 had mechanical gastrojejunoanal anastomosis with 30 mm linear stapler (Group B) and 44 had manual (hand sewn) 15 mm gastrojejunal anastomosis (Group C). Overall incidence of DS was 8.5% at M1 and M6. In LSG group (Group A), only 4 patients (1.49%) reported episodes of DS at M1 and 3 (1.12%) at M6. In Group B, 41 patients (17.90%) reported episodes of DS at M1 and 43 (18.78%) at M6. Group C experienced one case (2.27%) of DS at M1 and none (0%) at M6. Conclusions. Patients undergoing LRYGB, especially with larger gastrojejunal anastomosis, are more prone to developing DS following surgery than patients undergoing LSG or LRYGB with calibrated manual anastomosis

Comparison of stapled haemorrhoidopexy with traditional excisional surgery for haemorrhoidal disease (eTHoS): a pragmatic, multicentre, randomised controlled trial

Background Two commonly performed surgical interventions are available for severe (grade II–IV) haemorrhoids; traditional excisional surgery and stapled haemorrhoidopexy. Uncertainty exists as to which is most eff ective. The eTHoS trial was designed to establish the clinical effectiveness and cost-eff ectiveness of stapled haemorrhoidopexy compared with traditional excisional surgery. Methods The eTHoS trial was a large, open-label, multicentre, parallel-group, pragmatic randomised controlled trial done in adult participants (aged 18 years or older) referred to hospital for surgical treatment for grade II–IV haemorrhoids. Participants were randomly assigned (1:1) to receive either traditional excisional surgery or stapled haemorrhoidopexy. Randomisation was minimised according to baseline EuroQol 5 dimensions 3 level score (EQ-5D-3L), haemorrhoid grade, sex, and centre with an automated system to stapled haemorrhoidopexy or traditional excisional surgery. The primary outcome was area under the quality of life curve (AUC) measured with the EQ-5D-3L descriptive system over 24 months, assessed according to the randomised groups. The primary outcome measure was analysed using linear regression with adjustment for the minimisation variables. This trial is registered with the ISRCTN registry, number ISRCTN80061723. Findings Between Jan 13, 2011, and Aug 1, 2014, 777 patients were randomised (389 to receive stapled haemorrhoidopexy and 388 to receive traditional excisional surgery). Stapled haemorrhoidopexy was less painful than traditional excisional surgery in the short term and surgical complication rates were similar between groups. The EQ-5D-3L AUC score was higher in the traditional excisional surgery group than the stapled haemorrhoidopexy group over 24 months; mean diff erence –0·073 (95% CI –0·140 to –0·006; p=0·0342). EQ-5D-3L was higher for stapled haemorrhoidopexy in the fi rst 6 weeks after surgery, the traditional excisional surgery group had signifi cantly better quality of life scores than the stapled haemorrhoidopexy group. 24 (7%) of 338 participants who received stapled haemorrhoidopexy and 33 (9%) of 352 participants who received traditional excisional surgery had serious adverse events. Interpretation As part of a tailored management plan for haemorrhoids, traditional excisional surgery should be considered over stapled haemorrhoidopexy as the surgical treatment of choice

Electronic properties of guanine-based nanowires

We present a first-principle study of the electronic and conduction properties of a few classes of nanowires constituted of guanine (G) molecules, self-assembled in different geometries. We first analyze the effect of the vertical $\pi$-$\pi$ interaction in model G-stack columns. Then, we exploit the results obtained from those models to interpret the features of realistic stacked and hydrogen-bonded structures, namely the guanine quadruple helices and the planar ribbons. With respect to natural DNA, the different structures as well as the inclusion of metal cations, drastically affect the bonding pattern among the bases, introducing novel features in the electronic properties of the systems. These supramolecular G-aggregates, alternative to DNA, are expected to show intersting properties for molecular elec tronics applications.Comment: 30 pages (preprint format), 8 figures. To appear in Solid State Communications - Special Issue on "New advances on collective phenomena in one-dimensional systems

Synthesis, Purification and Crystallization of Guanine-rich RNA Oligonucleotides

Guanine-rich RNA oligonucleotides display many novel structural motifs in recent crystal structures. Here we describe the procedures of the chemical synthesis and the purification of such RNA molecules that are suitable for X-ray crystallographic studies. Modifications of the previous purification methods allow us to obtain better yields in shorter time. We also provide 24 screening conditions that are very effective in crystallization of the guanine-rich RNA oligonucleotides. Optimal crystallization conditions are usually achieved by adjustment of the concentration of the metal ions and pH of the buffer. Crystals obtained by this method usually diffract to high resolution

Crystallization and characterization of the thallium form of the Oxytricha nova G-quadruplex

The crystal structure of the Tl(+) form of the G-quadruplex formed from the Oxytricha nova telomere sequence, d(G(4)T(4)G(4)), has been solved to 1.55 Å. This G-quadruplex contains five Tl(+) ions, three of which are interspersed between adjacent G-quartet planes and one in each of the two thymine loops. The structure displays a high degree of similarity to the K(+) crystal structure [Haider et al. (2002), J. Mol. Biol., 320, 189–200], including the number and location of the monovalent cation binding sites. The highly isomorphic nature of the two structures, which contain such a large number of monovalent binding sites (relative to nucleic acid content), verifies the ability of Tl(+) to mimic K(+) in nucleic acids. Information from this report confirms and extends the assignment of (205)Tl resonances from a previous report [Gill et al. (2005), J. Am. Chem. Soc., 127, 16 723–16 732] where (205)Tl NMR was used to study monovalent cation binding to this G-quadruplex. The assignment of these resonances provides evidence for the occurrence of conformational dynamics in the thymine loop region that is in slow exchange on the (205)Tl timescale

Backbone-base inclination as a fundamental determinant of nucleic acid self- and cross-pairing

The crystal structure of the duplex formed by oligo(2′,3′-dideoxy-β-d-glucopyranosyl)nucleotides (homo-DNA) revealed strongly inclined backbone and base-pair axes [Egli,M., Pallan,P.S., Pattanayek,R., Wilds,C.J., Lubini,P., Minasov,G., Dobler,M., Leumann,C.J. and Eschenmoser,A. (2006) Crystal structure of homo-DNA and nature's choice of pentose over hexose in the genetic system. J. Am. Chem. Soc., 128, 10847–10856]. This inclination is easily perceived because homo-DNA exhibits only a modest helical twist. Conversely, the tight coiling of strands conceals that the backbone-base inclinations for A- (DNA and RNA) and B-form (DNA) duplexes differ considerably. We have defined a parameter ηB that corresponds to the local inclination between sugar-phosphate backbone and base plane in nucleic acid strands. Here, we show its biological significance as a predictive measure for the relative strand polarities (antiparallel, aps, or parallel, ps) in duplexes of DNA, RNA and artificial nucleic acid pairing systems. The potential of formation of ps duplexes between complementary 16-mers with eight A and U(T) residues each was investigated with DNA, RNA, 2′-O-methylated RNA, homo-DNA and p-RNA, the ribopyranosyl isomer of RNA. The thermodynamic stabilities of the corresponding aps duplexes were also measured. As shown previously, DNA is capable of forming both ps and aps duplexes. However, all other tested systems are unable to form stable ps duplexes with reverse Watson–Crick (rWC) base pairs. This observation illustrates the handicap encountered by nucleic acid systems with inclinations ηB that differ significantly from 0° to form a ps rWC paired duplex. Accordingly, RNA with a backbone-base inclination of −30°, pairs strictly in an aps fashion. On the other hand, the more or less perpendicular orientation of backbone and bases in DNA allows it to adopt a ps rWC paired duplex. In addition to providing a rationalization of relative strand polarity with nucleic acids, the backbone-base inclination parameter is also a determinant of cross-pairing. Thus, systems with strongly deviating ηB angles will not pair with each other. Nucleic acid pairing systems with significant backbone-base inclinations can also be expected to display different stabilities depending on which terminus carries unpaired nucleotides. The negative inclination of RNA is consistent with the higher stability of duplexes with 3′- compared to those with 5′-dangling ends

Functional binding of hexanucleotides to 3C protease of hepatitis A virus

Oligonucleotides as short as 6 nt in length have been shown to bind specifically and tightly to proteins and affect their biological function. Yet, sparse structural data are available for corresponding complexes. Employing a recently developed hexanucleotide array, we identified hexadeoxyribonucleotides that bind specifically to the 3C protease of hepatitis A virus (HAV 3Cpro). Inhibition assays in vitro identified the hexanucleotide 5′-GGGGGT-3′ (G5T) as a 3Cpro protease inhibitor. Using 1H NMR spectroscopy, G5T was found to form a G-quadruplex, which might be considered as a minimal aptamer. With the help of 1H, 15N-HSQC experiments the binding site for G5T was located to the C-terminal β-barrel of HAV 3Cpro. Importantly, the highly conserved KFRDI motif, which has previously been identified as putative viral RNA binding site, is not part of the G5T-binding site, nor does G5T interfere with the binding of viral RNA. Our findings demonstrate that sequence-specific nucleic acid–protein interactions occur with oligonucleotides as small as hexanucleotides and suggest that these compounds may be of pharmaceutical relevance

Interaction of Pyrrolobenzodiazepine (PBD) Ligands with Parallel Intermolecular G-Quadruplex Complex Using Spectroscopy and ESI-MS

Studies on ligand interaction with quadruplex DNA, and their role in stabilizing the complex at concentration prevailing under physiological condition, has attained high interest. Electrospray ionization mass spectrometry (ESI-MS) and spectroscopic studies in solution were used to evaluate the interaction of PBD and TMPyP4 ligands, stoichiometry and selectivity to G-quadruplex DNA. Two synthetic ligands from PBD family, namely pyrene-linked pyrrolo[2,1-c][1,4]benzodiazepine hybrid (PBD1), mixed imine-amide pyrrolobenzodiazepine dimer (PBD2) and 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin (TMPyP4) were studied. G-rich single-stranded oligonucleotide d(5′GGGGTTGGGG3′) designated as d(T2G8), from the telomeric region of Tetrahymena Glaucoma, was considered for the interaction with ligands. ESI-MS and spectroscopic methods viz., circular dichroism (CD), UV-Visible, and fluorescence were employed to investigate the G-quadruplex structures formed by d(T2G8) sequence and its interaction with PBD and TMPyP4 ligands. From ESI-MS spectra, it is evident that the majority of quadruplexes exist as d(T2G8)2 and d(T2G8)4 forms possessing two to ten cations in the centre, thereby stabilizing the complex. CD band of PBD1 and PBD2 showed hypo and hyperchromicity, on interaction with quadruplex DNA, indicating unfolding and stabilization of quadruplex DNA complex, respectively. UV-Visible and fluorescence experiments suggest that PBD1 bind externally where as PBD2 intercalate moderately and bind externally to G-quadruplex DNA. Further, melting experiments using SYBR Green indicate that PBD1 unfolds and PBD2 stabilizes the G-quadruplex complex. ITC experiments using d(T2G8) quadruplex with PBD ligands reveal that PBD1 and PBD2 prefer external/loop binding and external/intercalative binding to quadruplex DNA, respectively. From experimental results it is clear that the interaction of PBD2 and TMPyP4 impart higher stability to the quadruplex complex