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Michael J. A. Tanner - One of the best experts on this subject based on the ideXlab platform.

  • the low incidence Blood Group Antigen wda is associated with the substitution val557 met in human erythrocyte band 3 ae1
    Vox Sanguinis, 1996
    Co-Authors: Lesley J Bruce, K Ridgwell, Teresa Zelinski, Michael J. A. Tanner
    Abstract:

    The Waldner Blood Group Antigen (Wda) was first identified in members of a Hutterite kindred. Evidence that the gene governing the Waldner polymorphism is located on chromosome 17, and the observation that the Antigen is inactivated by chymotrypsin prompted the investigation of a possible association between Wda and band 3. Single Stranded Conformational Polymorphism (SSCP) analysis and DNA sequence analysis of the AE1 gene, from subjects of known Waldner phenotypes, showed a heterozygous mutation leading to the substitution Val557-->Met in the presumptive Wd(a+) heterozygotes. Therefore the Wda Blood Group Antigen is associated with the presence of Met557 on band 3. the Waldner Antigen has been assigned to the Diego Blood Group system with the International Society of Blood Transfusion number D15.

  • band 3 memphis variant ii altered stilbene disulfonate binding and the diego dia Blood Group Antigen are associated with the human erythrocyte band 3 mutation pro854 leu
    Journal of Biological Chemistry, 1994
    Co-Authors: Lesley J Bruce, David J. Anstee, F A Spring, Michael J. A. Tanner
    Abstract:

    Abstract Band 3 Memphis is a commonly occurring polymorphic form of the human red cell anion transporter (band 3, AE1). Band 3 Memphis migrates more slowly on an SDS-polyacrylamide gel than normal band 3 and results from a point mutation Lys56-->Glu. Two types of band 3 Memphis, variants I and II, can be distinguished by their susceptibility to covalent labeling with H2DIDS (4,4'-diisothiocyanato-2,2'-dihydrostilbene disulfonate). Memphis variant II is more readily labeled than Memphis variant I or normal band 3. The Memphis variant II is also associated with the presence of the Diego (Dia) Blood Group Antigen on the red cells. We have shown that Memphis variant II carries the polymorphism Pro854-->Leu, as well as Lys56-->Glu. The Blood Group Antigen (Dia) present at the surface of Memphis variant II type red cells suggests the mutation Pro854-->Leu causes a change in the structure of an extracellular loop of Memphis variant II band 3. We discuss possible ways in which the mutation Pro854-->Leu affects the reactivity of Lys539 to covalent reaction with H2DIDS.

  • Studies on the glycoprotein associated with Rh (rhesus) Blood Group Antigen expression in the human red Blood cell membrane.
    The Journal of biological chemistry, 1994
    Co-Authors: K Ridgwell, David J. Anstee, S. A. C. Eyers, W. J. Mawby, Michael J. A. Tanner
    Abstract:

    The Blood Group Rh Antigens are associated with non-glycosylated 30-kDa erythrocyte membrane proteins (the Rh30 polypeptides) and the Rh glycoprotein. We used antipeptide antibodies to study the Rh glycoprotein in human erythrocyte membranes. The Rh glycoprotein was present in Rhnull U+ve cells. However, the N-glycan chain of the Rh glycoprotein in Rhnull U+ve cells was smaller than in normal cells. In contrast, the N-glycan chain of the Rh glycoprotein was larger than normal in glycophorin B-deficient red cells. We suggest that this observation reflects a lower rate of movement of newly synthesized Rh glycoprotein through intracellular membranes to the cell surface in the absence of glycophorin B, and that in normal red cells glycophorin B facilitates the movement of the Rh protein complex to the cell surface. Our results provide evidence for the intracellular interaction of at least three proteins, the Rh glycoprotein, Rh30 polypeptides, and glycophorin B during the biosynthesis and cell surface expression of the Rh complex. These observations are likely to be important for the successful design of expression systems for the Blood Group Rh Antigens.

Xi Jiang - One of the best experts on this subject based on the ideXlab platform.

  • association between norovirus and rotavirus infection and histo Blood Group Antigen types in vietnamese children
    Journal of Clinical Microbiology, 2014
    Co-Authors: Nguyen Van Trang, Hau Thibich Vu, Nhung Thihong Le, Pengwei Huang, Xi Jiang
    Abstract:

    ABSTRACT Norovirus and rotavirus are the two most important causes of acute gastroenteritis in children worldwide. Both norovirus and rotavirus recognize human histo-Blood Group Antigens (HBGAs), and multiple binding patterns for HBGAs have been reported. To explore the role of HBGAs in host susceptibility to norovirus and rotavirus, we conducted a cross-sectional study in children hospitalized with diarrhea in northern Vietnam from September 2010 through September 2012. Of 260 children with paired stool and saliva samples, 158 (61%) were classified as HBGA secretors (Le a−b+ ), 31 (12%) were nonsecretors (Le a+b− ), and 71 (27%) were partial secretors (Le a+b+ ). Norovirus was detected in 50 patients (19%), with viral genotypes GII.3 ( n = 28) and GII.4 ( n = 22) being the most common. All children infected with norovirus strains of genotype GII.4 were either HBGA secretors or partial secretors. Of the 28 GII.3 cases, 12 involved HBGA secretors, 11 partial secretors, and 5 nonsecretors. A total of 85 children tested positive for rotavirus, 74 of whom were infected with genotype P[8], 5 with P[4], and 6 with P[6]; all were HBGA secretors or partial secretors. This is the first epidemiological study demonstrating in a population that HBGA phenotype is a key susceptibility factor for both norovirus and rotavirus infections in children.

  • the p domain of norovirus capsid protein forms a subviral particle that binds to histo Blood Group Antigen receptors
    Journal of Virology, 2005
    Co-Authors: Ming Tan, Xi Jiang
    Abstract:

    Norovirus is the most important cause of nonbacterial acute gastroenteritis. We have shown previously that the isolated P domain containing the hinge forms a dimer and binds to histo-Blood Group Antigen (HBGA) receptors with a low affinity (M. Tan, R. S. Hegde, and X. Jiang, J. Virol. 78:6233-6242, 2004). Here, we reported that the P domain of VA387 without the hinge forms a small particle with a significantly increased receptor binding affinity. An end-linked oligopeptide containing one or more cysteines promoted P-particle formation by forming intermolecular disulfide bridges. The binding sensitivity of the P particle to HBGAs was enhanced >700-fold compared to the P dimer, which was comparable to that of virus-like particles. The binding specificity of the P particle was further confirmed by strong binding to the Caco-2 cells, a human colon carcinoma cell line. This binding enhancement was observed in the P particles of both norovirus GI and GII strains. The P particle is estimated to contain 12 P dimers, in which the P2 subdomain builds up the outer layer, while the P1 subdomain forms the internal core. Taken together, our data indicate that the P domain is involved not only in dimerization but also in polymerization of the protein during the capsid assembling. The enhanced receptor binding of the P particle reflects the intrinsic feature of the viral capsid. The easy production of the P particle and its strong binding to HBGAs suggest that the P particle is useful in studying pathogenesis and morphogenesis of norovirus and candidates for antiviral or vaccine development.

  • norovirus and its histo Blood Group Antigen receptors an answer to a historical puzzle
    Trends in Microbiology, 2005
    Co-Authors: Ming Tan, Xi Jiang
    Abstract:

    Recent findings demonstrate that human histo-Blood Group Antigens (HBGAs) serve as receptors for norovirus infection. The recognition of human HBGAs by noroviruses is a typical protein-carbohydrate interaction, in which the protruding domain of the viral capsid protein forms an interface with the oligosaccharide side-chains of the Antigens, with a wide diversity among different strains. The human HBGA system is also highly polymorphic and is controlled by multiple gene families with silent alleles. The presence of such diversified molecules on the cell surfaces indicates a possible host defense mechanism against the changing external environment. As mild pathogens that replicate possibly only in the intestinal tract, noroviruses have developed unique strategies to overcome the host defense system. This has been shown by their genetic and structural variations, which explains why norovirus-associated diseases are so common and widespread in every population worldwide.

  • the p domain of norovirus capsid protein forms dimer and binds to histo Blood Group Antigen receptors
    Journal of Virology, 2004
    Co-Authors: Ming Tan, Rashmi S Hegde, Xi Jiang
    Abstract:

    Noroviruses (NVs) are the most important pathogen of epidemic nonbacterial gastroenteritis. The recent finding that NVs recognize human histo-Blood Group Antigens (HBGAs) as receptors provided a new approach to study the pathogenesis of NVs. Using computational and site-directed mutagenesis approaches, our investigators previously identified a plausible binding pocket in the P domain of the NV capsids. In this study, we further characterize the role of the P domain in the interaction with human HBGA receptors using three NV strains representing three binding patterns. Our results show that the isolated P domain, although it did not form virus-like particles (VLPs), formed dimers, and the dimers bound HBGAs with the same patterns as those of the intact viral capsids. In contrast, the S domain, which formed small, thin-layer VLPs, did not bind A, B, or H HBGAs. A chimera containing the S domain of VA387 and the P domain of MOH revealed a binding pattern of the P donor strain (MOH). Deletion experiments revealed that an intact P domain is necessary for receptor binding. The P domain dimers are stable over a broad range of pH (2 to 11) or under strong denaturing conditions. Taken together, our results suggest that the P domain of NV contains essential elements for strain-specific binding to receptors. Further study of the P domain will provide useful information about the virus-receptor interaction. The high yield and easy production of the recombinant P protein in the Escherichia coli expression system will provide a simple approach to this goal.

Mary K. Estes - One of the best experts on this subject based on the ideXlab platform.

  • comparison of microneutralization and histo Blood Group Antigen blocking assays for functional norovirus antibody detection
    The Journal of Infectious Diseases, 2019
    Co-Authors: Robert L Atmar, Khalil Ettayebi, Vijayalakshmi B Ayyar, Frederick H Neill, Ralph P Braun, Sasirekha Ramani, Mary K. Estes
    Abstract:

    BACKGROUND The development of an in vitro cultivation system for human noroviruses allows the measurement of neutralizing antibody levels. METHODS Serum neutralizing antibody levels were determined using a GII.4/Sydney/2012-like virus in human intestinal enteroids in samples collected before and 4 weeks after administration of an investigational norovirus vaccine and were compared with those measured in histo-Blood Group Antigen (HBGA)-blocking assays. RESULTS Neutralizing antibody seroresponses were observed in 71% of 24 vaccinated adults, and antibody levels were highly correlated (r = 0.82, P < .001) with those measured by HBGA blocking. CONCLUSIONS HBGA-blocking antibodies are a surrogate for neutralization in human noroviruses. CLINICAL TRIALS REGISTRATION NCT02475278.

  • structural analysis of determinants of histo Blood Group Antigen binding specificity in genoGroup i noroviruses
    Journal of Virology, 2014
    Co-Authors: Sreejesh Shanker, Rita Czako, Robert L Atmar, Mary K. Estes, Banumathi Sankaran, B V V Prasad
    Abstract:

    Human noroviruses (NoVs) cause acute epidemic gastroenteritis. Susceptibility to the majority of NoV infections is determined by genetically controlled secretor-dependent expression of histo-Blood Group Antigens (HBGAs), which are also critical for NoV attachment to host cells. Human NoVs are classified into two major genoGroups (genoGroup I [GI] and GII), with each genoGroup further divided into several genotypes. GII NoVs are more prevalent and exhibit periodic emergence of new variants, suggested to be driven by altered HBGA binding specificities and Antigenic drift. Recent epidemiological studies show increased activity among GI NoVs, with some members showing the ability to bind nonsecretor HBGAs. NoVs bind HBGAs through the protruding (P) domain of the major capsid protein VP1. GI NoVs, similar to GII, exhibit significant sequence variations in the P domain; it is unclear how these variations affect HBGA binding specificities. To understand the determinants of possible strain-specific HBGA binding among GI NoVs, we determined the structure of the P domain of a GI.7 clinical isolate and compared it to the previously determined P domain structures of GI.1 and GI.2 strains. Our crystallographic studies revealed significant structural differences, particularly in the loop regions of the GI.7 P domain, altering its surface topography and electrostatic landscape and potentially indicating Antigenic variation. The GI.7 strain bound to H- and A-type, Lewis secretor, and Lewis nonsecretor families of HBGAs, allowing us to further elucidate the structural determinants of nonsecretor HBGA binding among GI NoVs and to infer several contrasting and generalizable features of HBGA binding in the GI NoVs. IMPORTANCE Human noroviruses (NoVs) cause acute epidemic gastroenteritis. Recent epidemiological studies have shown increased prevalence of genoGroup I (GI) NoVs. Although secretor-positive status is strongly correlated with NoV infection, cases of NoV infection associated with secretor-negative individuals are reported. Biochemical studies have shown that GI NoVs exhibit genotype-dependent binding to nonsecretor histo-Blood Group Antigens (HBGAs). From our crystallographic studies of a GI.7 NoV, in comparison with previous studies on GI.1 and GI.2 NoVs, we show that genotypic differences translate to extensive structural changes in the loop regions that significantly alter the surface topography and electrostatic landscape of the P domain; these features may be indicative of Antigenic variations contributing to serotypic differentiation in GI NoVs and also differential modulation of the HBGA binding characteristics. A significant finding is that the threshold length and the structure of one of the loops are critical determinants in the binding of GI NoVs to nonsecretor HBGAs.

  • cell attachment protein vp8 of a human rotavirus specifically interacts with a type histo Blood Group Antigen
    Nature, 2012
    Co-Authors: Liya Hu, Rita Czako, Mary K. Estes, Sue E Crawford, Nicolas W Cortespenfield, David F Smith, Jacques Le Pendu, B Venkataram V Prasad
    Abstract:

    This crystallographic study shows the attachment of human rotavirus VP8* to histo Blood Group A Antigen, and suggests how changes within the structure of VP8* could allow switching from sialylated to non-sialylated glycan receptor. Rotaviruses are the major pathogens of infantile gastroenteritis. They attach to the surfaces of cells through interactions with specific cellular glycans. Animal rotaviruses bind to glycans with terminal sialic acid, whereas human rotavirus strains are sialidase insensitive. Venkataram Prasad and colleagues now show that certain human rotavirus strains bind to and infect cells through A-type histo-Blood Group Antigen (HBGA), suggesting that susceptibility to specific human rotavirus strains might be influenced by different Blood-Group Antigens, a phenomenon reported in Helicobacter pylori and norovirus infection. Crystallographic studies show how HBGA binds to the attachment protein of human norovirus (VP8), and suggest how subtle changes in the structure of VP8 might allow receptor switching. As with many other viruses, the initial cell attachment of rotaviruses, which are the major causative agent of infantile gastroenteritis, is mediated by interactions with specific cellular glycans1,2,3,4. The distally located VP8* domain of the rotavirus spike protein VP4 (ref. 5) mediates such interactions. The existing paradigm is that ‘sialidase-sensitive’ animal rotavirus strains bind to glycans with terminal sialic acid (Sia), whereas ‘sialidase-insensitive’ human rotavirus strains bind to glycans with internal Sia such as GM1 (ref. 3). Although the involvement of Sia in the animal strains is firmly supported by crystallographic studies1,3,6,7, it is not yet known how VP8* of human rotaviruses interacts with Sia and whether their cell attachment necessarily involves sialoglycans. Here we show that VP8* of a human rotavirus strain specifically recognizes A-type histo-Blood Group Antigen (HBGA) using a glycan array screen comprised of 511 glycans, and that virus infectivity in HT-29 cells is abrogated by anti-A-type antibodies as well as significantly enhanced in Chinese hamster ovary cells genetically modified to express the A-type HBGA, providing a novel paradigm for initial cell attachment of human rotavirus. HBGAs are genetically determined glycoconjugates present in mucosal secretions, epithelia and on red Blood cells8, and are recognized as susceptibility and cell attachment factors for gastric pathogens like Helicobacter pylori9 and noroviruses10. Our crystallographic studies show that the A-type HBGA binds to the human rotavirus VP8* at the same location as the Sia in the VP8* of animal rotavirus, and suggest how subtle changes within the same structural framework allow for such receptor switching. These results raise the possibility that host susceptibility to specific human rotavirus strains and pathogenesis are influenced by genetically controlled expression of different HBGAs among the world’s population.

  • Cell attachment protein VP8* of a human rotavirus specifically interacts with A-type histo-Blood Group Antigen
    Nature, 2012
    Co-Authors: Sue E Crawford, Rita Czako, Mary K. Estes, David F Smith, Jacques Le Pendu, Nicolas W. Cortes-penfield, B Venkataram V Prasad
    Abstract:

    As with many other viruses, the initial cell attachment of rotaviruses, which are the major causative agent of infantile gastroenteritis, is mediated by interactions with specific cellular glycans. The distally located VP8* domain of the rotavirus spike protein VP4 (ref. 5) mediates such interactions. The existing paradigm is that 'sialidase-sensitive' animal rotavirus strains bind to glycans with terminal sialic acid (Sia), whereas 'sialidase-insensitive' human rotavirus strains bind to glycans with internal Sia such as GM1 (ref. 3). Although the involvement of Sia in the animal strains is firmly supported by crystallographic studies, it is not yet known how VP8* of human rotaviruses interacts with Sia and whether their cell attachment necessarily involves sialoglycans. Here we show that VP8* of a human rotavirus strain specifically recognizes A-type histo-Blood Group Antigen (HBGA) using a glycan array screen comprised of 511 glycans, and that virus infectivity in HT-29 cells is abrogated by anti-A-type antibodies as well as significantly enhanced in Chinese hamster ovary cells genetically modified to express the A-type HBGA, providing a novel paradigm for initial cell attachment of human rotavirus. HBGAs are genetically determined glycoconjugates present in mucosal secretions, epithelia and on red Blood cells, and are recognized as susceptibility and cell attachment factors for gastric pathogens like Helicobacter pylori and noroviruses. Our crystallographic studies show that the A-type HBGA binds to the human rotavirus VP8* at the same location as the Sia in the VP8* of animal rotavirus, and suggest how subtle changes within the same structural framework allow for such receptor switching. These results raise the possibility that host susceptibility to specific human rotavirus strains and pathogenesis are influenced by genetically controlled expression of different HBGAs among the world's population.

  • serum hemagglutination inhibition activity correlates with protection from gastroenteritis in persons infected with norwalk virus
    Clinical and Vaccine Immunology, 2012
    Co-Authors: Rita Czako, Mark A Gilger, Robert L Atmar, Antone R. Opekun, David Y. Graham, Mary K. Estes
    Abstract:

    ABSTRACT A hemagglutination inhibition (HAI) assay to assess serum antibody responses following Norwalk virus (NV) infection was developed. HAI activity increased significantly in individuals experimentally infected with NV ( n = 18) and correlated with antibody levels measured in a histo-Blood Group Antigen (HBGA) blocking assay. Prechallenge HAI antibody levels also correlated with protection from the development of gastroenteritis (Mann-Whitney test, P = 0.02). The HAI assay is another assay suitable for the detection of antibody that correlates with protection from Norwalk virus-associated disease.

Christian Prinz - One of the best experts on this subject based on the ideXlab platform.

  • the helicobacter pylori Blood Group Antigen binding adhesin facilitates bacterial colonization and augments a nonspecific immune response
    Journal of Immunology, 2002
    Co-Authors: Roland Rad, Markus Gerhard, W Schepp, Martin Schoniger, Ingrid Becker, Thomas Rosch, Roland Lang, Hermann Wagner, Christian Prinz
    Abstract:

    Presence of the Helicobacter pylori adherence factor Blood Group Ag-binding adhesin (BabA; binding to Lewisb (Leb)) is associated with ulcer disease, adenocarcinoma, and precancerous lesions. The importance of BabA for bacterial colonization and the inflammatory response is unknown. A total of 141 antral biopsies from H. pylori-infected patients were assessed in regard to the degree of granulocytic (G0°–G3°) and lymphocytic (L1°–L3°) infiltration. DNA genotypes of babA2 (the transcriptionally active gene of BabA), cagA, and vacAs1/2 were determined by PCR. Colonization density and Leb status on gastric epithelial cells were determined by immunohistochemistry. Real-time quantitative (TaqMan) RT-PCR determined mRNA expression of IL-8, TNF -α, and the Th1 markers IFN-γ and the IL-12R β2 chain. A total of 91% of infected patients were Leb positive. The vacAs1+/cagA+ strains harboring babA2 showed significantly higher levels of granulocytic infiltration, bacterial colonization, and IL-8 mRNA than vacAs1+/cagA+ strains lacking babA2. IL-8 mRNA and protein production by KATO III cells in vitro increased dose dependently with addition of different numbers of type 1 strains (G27 and 2808 strains, 0.1–20 bacteria/cell). The mRNA expression of TNF-α, IFN-γ, and IL-12R β2 was higher in H. pylori-positive patients than in controls, but it did not differ significantly between patients infected with different strain types. These data suggest that BabA facilitates colonization of H. pylori and thereby increases IL-8 response, resulting in enhanced mucosal inflammation. Infection with strains harboring BabA thereby augment a nonspecific immune response, whereas the Th1 response toward H. pylori appears to be independent of BabA, cytotoxin-associated gene A, or vacuolating cytotoxin.

  • key importance of the helicobacter pylori adherence factor Blood Group Antigen binding adhesin during chronic gastric inflammation
    Cancer Research, 2001
    Co-Authors: Christian Prinz, Roland Rad, W Schepp, Meinhard Classen, Martin Schoniger, Ingrid Becker, Erwin Keiditsch, Stephan Wagenpfeil, Thomas Rosch, Markus Gerhard
    Abstract:

    Helicobacter pylori has been assigned as a class I carcinogen because of its relation to gastric adenocarcinoma. Chronic H. pylori infection may lead to severe gastritis, glandular atrophy (AT), and intestinal metaplasia (IM). Strains secreting the vacuolating toxin VacA and producing the cytotoxin-associated Antigen CagA (type 1 strains), as well as the Blood Group Antigen binding adhesin (BabA) targeting Lewis(b) Antigens, have been associated previously with distal gastric adenocarcinoma (M. Gerhard et al., Proc. Natl. Acad. Sci. USA, 96: 12778-12783, 1999) and may therefore also be related to lesions preceding gastric cancer. Antral and corpus biopsies were collected from 451 patients; 151 were H. pylori positive, as determined by PCR. Gastric biopsies were histologically evaluated for activity of gastritis (G0-G3, granulocyte infiltration), chronicity of gastritis (L1-L3, lymphocyte infiltration), and the presence of IM and/or AT according to the Sydney classification. Simultaneously, the presence of bacterial genes encoding virulence and adherence factors (racAs1/s2, cagA, and babA2) was determined by PCR. The presence of cagA+ and vacAs1 (alone or combined) both correlated with activity and chronicity of gastritis (P < 0.05); however, the overall prevalence of these genes was 60 or 72%, respectively, and was thus relatively frequent. The babA2 gene, encoding the adhesin BabA, was detected in 38% of infected patients and was correlated with the activity of gastritis in antrum and corpus (P < 0.005). cagA+/vacAs1+ strains (suggesting the presence of type 1 strains) that were also babA2 positive were detected more frequently in patients with severe histological alterations (such as G3, IM, or AT) compared with subjects without these changes (P < 0.01). cagA+/vacAs1+ strains that were babA2 negative, however, lacked a significant correlation with severe histological changes, activity, or chronicity of gastritis in antrum and corpus. Adherence of H. pylori via BabA appears to be of importance for efficient delivery of VacA and CagA and may play a special role in the pathogenesis of severe histological changes.

  • clinical relevance of the helicobacter pylori gene for Blood Group Antigen binding adhesin
    Proceedings of the National Academy of Sciences of the United States of America, 1999
    Co-Authors: Markus Gerhard, Norbert Lehn, Nina Neumayer, Thomas Boren, Roland Rad, W Schepp, Stephan Miehlke, Meinhard Classen, Christian Prinz
    Abstract:

    Infection with Helicobacter pylori is associated with different human gastric diseases. Biochemical studies, in vitro adherence assays, and in vivo animal models revealed that epithelial attachment of H. pylori can be mediated by the Blood-Group Antigen-binding adhesin (BabA) targeting human Lewisb surface epitopes. Studies with transgenic mice expressing the Lewisb epitope have shown that such attachment can alter disease outcome. In the current study, the presence of the babA2 gene encoding the adhesin was investigated in clinical isolates from a German population by using PCR and reverse transcription–PCR. A positive genotype was correlated to allelic variations in the genes encoding VacA and CagA and also to the prevalence of duodenal ulcer, distal gastric adenocarcinoma, mucosa-associated lymphoid tissue lymphoma, and antral gastritis. The presence of babA2 was significantly associated with duodenal ulcer (P = 0.0002) and adenocarcinoma (P = 0.033). In contrast, type 1 strains (vacAs1- and cagA-positive) were associated with only duodenal ulcer (P = 0.004) but not adenocarcinoma (P = 0.235). Genotype presence of babA2, vacAs1, and cagA (“triple-positive” strains) showed a highly significant correlation to the prevalence of ulcer (P = 0.000002) and adenocarcinoma (P = 0.014) and discriminated significantly better between disease outcome than did the current type 1 classification. These results indicate that the babA2 gene is of high clinical relevance and would be a useful marker to identify patients who are at higher risk for specific H. pylori-related diseases.

Santosh Kumar Patnaik - One of the best experts on this subject based on the ideXlab platform.

  • bgmut database of allelic variants of genes encoding human Blood Group Antigens
    Transfusion Medicine and Hemotherapy, 2014
    Co-Authors: Santosh Kumar Patnaik, Wolfgang Helmberg, Olga O Blumenfeld
    Abstract:

    The Blood Group Antigen Gene MUTation (BGMUT) database documents variations in genes of human Blood Group systems. In March 2014, the database, accessible at www.ncbi.nlm.nih.gov/gv/mhc/xslcgi.cgi?cmd=bgmut, listed 1,545 alleles of 44 genes of 34 Blood Group systems. Besides allelic information, the BGMUT resource also presents comprehensive and current information on Blood Group systems. This review describes the database and notes its utility for the transfusion medicine and human genetics communities.

  • allelic genes of Blood Group Antigens a source of human mutations and csnps documented in the Blood Group Antigen gene mutation database
    Human Mutation, 2004
    Co-Authors: Olga O Blumenfeld, Santosh Kumar Patnaik
    Abstract:

    In this report, we analyze data assembled in the Blood Group Antigen Gene Mutation Database (www.bioc.aecom.yu.edu/bgmut/index.htm), which describes sequence information on human genes associated with expression of the various serologically-determined Blood Group phenotypes. The database documents 38 genetic loci and a total of 624 alleles that together encode a large repertoire of proteins and constitute 27 serologically-defined Blood Group systems. Analysis of sequence variation patterns across alleles of a number of genes is focused on their molecular profiles, including mutational sites and recurrence, patterns of gene rearrangements in duplicated gene families, correlation of predicted location of epitopes in extracellular loops with sites of alterations, and effects of mutations on protein expression. That information, and the relative ease of identifying individuals bearing variant alleles, has led to the proposal that genes encoding Blood Group Antigens are an important and unique resource for studies of human DNA variation. Another focus is on mutations in regions that encode the Antigenic epitopes and on their occurrence in world populations. These mutations may be viewed as coding single nucleotide polymorphisms (cSNPs). We propose that one Group of these cSNPs, which are known to occur with significant frequency in all world populations, could serve as well-validated genetic markers. In addition, specific mutations in a number of "low incidence" and rare alleles could serve as cSNPs specific for a given population. The allelic frequencies of these mutations and knowledge of their world-wide occurrence add a valuable dataset to the existing cSNP pools documented in SNP databases.

  • allelic genes of Blood Group Antigens a source of human mutations and csnps documented in the Blood Group Antigen gene mutation database
    Human Mutation, 2004
    Co-Authors: Olga O Blumenfeld, Santosh Kumar Patnaik
    Abstract:

    In this report, we analyze data assembled in the Blood Group Antigen Gene Mutation Database (www.bioc.aecom.yu.edu/bgmut/index.htm), which describes sequence information on human genes associated with expression of the various serologically-determined Blood Group phenotypes. The database documents 38 genetic loci and a total of 624 alleles that together encode a large repertoire of proteins and constitute 27 serologically-defined Blood Group systems. Analysis of sequence variation patterns across alleles of a number of genes is focused on their molecular profiles, including mutational sites and recurrence, patterns of gene rearrangements in duplicated gene families, correlation of predicted location of epitopes in extracellular loops with sites of alterations, and effects of mutations on protein expression. That information, and the relative ease of identifying individuals bearing variant alleles, has led to the proposal that genes encoding Blood Group Antigens are an important and unique resource for studies of human DNA variation. Another focus is on mutations in regions that encode the Antigenic epitopes and on their occurrence in world populations. These mutations may be viewed as coding single nucleotide polymorphisms (cSNPs). We propose that one Group of these cSNPs, which are known to occur with significant frequency in all world populations, could serve as well-validated genetic markers. In addition, specific mutations in a number of “low incidence” and rare alleles could serve as cSNPs specific for a given population. The allelic frequencies of these mutations and knowledge of their world-wide occurrence add a valuable dataset to the existing cSNP pools documented in SNP databases. Hum Mutat 23:8–16, 2004. © 2003 Wiley-Liss, Inc.