416 research outputs found

    Deformations for Function Fields

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    AbstractWe consider a question of describing the one-dimensionalP-adic representations that lift a given representation over a finite field of the absolute Galois group of a function field. In this case, the characterization of abelianp-power extensions of fields of characteristicpcan be extended to abelian pro-p-extensions, and refined to allow only restricted ramification at the places ofK, and can be a tool for analyzing one-dimensionP-adic representations. We then turn to the problem of classifying those representations which can be realized as the action of the Galois group on the division points of a rank one Drinfeld module, discussing both results and a conjecture about the form of the representations that arise in this manner

    Multiplatform urinary metabolomics profiling to discriminate cachectic from non-cachectic colorectal cancer patients: Pilot results from the ColoCare Study

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    Cachexia is a multifactorial syndrome that is characterized by loss of skeletal muscle mass in cancer patients. The biological pathways involved remain poorly characterized. Here, we compare urinary metabolic profiles in newly diagnosed colorectal cancer patients (stage I-IV) from the ColoCare Study in Heidelberg, Germany. Patients were classified as cachectic

    The Proportion of Fixed-Point-Free Elements of a Transitive Permutation Group

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    In 1990 Hendrik W. Lenstra, Jr. asked the following question: if G is a transitive permutation group of degree n and A is the set of elements of G that move every letter, then can one find a lower bound (in terms of n) for f(G) = |A|/|G|? Shortly thereafter, Arjeh Cohen showed that 1/n is such a bound. Lenstra’s problem arose from his work on the number field sieve. A simple example of how f(G) arises in number theory is the following: if h is an irreducible polynomial over the integers, consider the proportion: |{primes ≤ x | h has no zeroes mod p}| / |{primes ≤ x}| As x → ∞, this ratio approaches f(G), where G is the Galois group of h considered as a permutation group on its roots. Our results in this paper include explicit calculations of f(G) for groups G in several families. We also obtain results useful for computing f(G) when G is a wreath product or a direct product of permutation groups. Using this we show that {f(G) | G is transitive} is dense in [0, 1]. The corresponding conclusion is true if we restrict G to primitive groups

    Crystal structure of 1-aminocyclopropane-1-carboxylate deaminase from Hansenula saturnus

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    This research was originally published in Journal of Biological Chemistry. Min Yao, T. Ose, Hiroshi Sugimoto, Atsushi Horiuchi, Atsushi Nakagawa, Soichi Wakatsuki, Daisuke Yokoii, Toyotaka Murakamii, Mamoru Honmai, and Isao Tanaka. Crystal structure of 1-aminocyclopropane-1-carboxylate deaminase from Hansenula saturnus. J. Biol. Chem. 2000; 275, 34557-34565. © the American Society for Biochemistry and Molecular Biology

    Versatile Virus-Like Particle Carrier for Epitope Based Vaccines

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    BACKGROUND: Recombinant proteins and in particular single domains or peptides are often poorly immunogenic unless conjugated to a carrier protein. Virus-like-particles are a very efficient means to confer high immunogenicity to antigens. We report here the development of virus-like-particles (VLPs) derived from the RNA bacteriophage AP205 for epitope-based vaccines. METHODOLOGY/PRINCIPAL FINDINGS: Peptides of angiotensin II, S.typhi outer membrane protein (D2), CXCR4 receptor, HIV1 Nef, gonadotropin releasing hormone (GnRH), Influenza A M2-protein were fused to either N- or C-terminus of AP205 coat protein. The A205-peptide fusions assembled into VLPs, and peptides displayed on the VLP were highly immunogenic in mice. GnRH fused to the C-terminus of AP205 induced a strong antibody response that inhibited GnRH function in vivo. Exposure of the M2-protein peptide at the N-terminus of AP205 resulted in a strong M2-specific antibody response upon immunization, protecting 100% of mice from a lethal influenza infection. CONCLUSIONS/SIGNIFICANCE: AP205 VLPs are therefore a very efficient and new vaccine system, suitable for complex and long epitopes, of up to at least 55 amino acid residues in length. AP205 VLPs confer a high immunogenicity to displayed epitopes, as shown by inhibition of endogenous GnRH and protective immunity against influenza infection

    Production and purification of chimeric HBc virus-like particles carrying influenza virus LAH domain as vaccine candidates

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    Background: The lack of a universal influenza vaccine is a global health problem. Interest is now focused on structurally conserved protein domains capable of eliciting protection against a broad range of influenza virus strains. The long alpha helix (LAH) is an attractive vaccine component since it is one of the most conserved influenza hemagglutinin (HA) stalk regions. For an improved immune response, the LAH domain from H3N2 strain has been incorporated into virus-like particles (VLPs) derived from hepatitis B virus core protein (HBc) using recently developed tandem core technology. Results: Fermentation conditions for recombinant HBc-LAH were established in yeast Pichia pastoris and a rapid and efficient purification method for chimeric VLPs was developed to match the requirements for industrial scale-up. Purified VLPs induced strong antibody responses against both group 1 and group 2 HA proteins in mice. Conclusion: Our results indicate that the tandem core technology is a useful tool for incorporation of highly hydrophobic LAH domain into HBc VLPs. Chimeric VLPs can be successfully produced in bioreactor using yeast expression system. Immunologic data indicate that HBc VLPs carrying the LAH antigen represent a promising universal influenza vaccine component
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