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Artículos de revistas sobre el tema "Cholerae sialidase"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 20 de febrero de 2023

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1

Jung, K., M. Pergande y S. Klotzek. "Sialidase from different sources compared for electrophoretically separating serum alkaline phosphatase fractions from liver and bone." Clinical Chemistry 35, n.º 9 (1 de septiembre de 1989): 1955–57. http://dx.doi.org/10.1093/clinchem/35.9.1955.

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Abstract We compared sialidase (neuraminidase; EC 3.2.1.18) from Vibrio cholerae, Clostridium perfringens, and Arthrobacter ureafaciens, seeking to improve the electrophoretic separation of the liver and bone isoenzymes of alkaline phosphatase (EC 3.1.3.1) on cellulose acetate membranes. Resolution is decisively determined by the type and activity of sialidase used in the preincubation of serum sample. Sialidase from Arthrobacter ureafaciens is not suited for this method. For optimal separation of the two isoenzymes we recommend the use of sialidase from Vibrio cholerae, determination of its activity with a standard procedure such as described here (mucin or sialyl lactose as substrates), and a final concentration of sialidase activity of 2.0 or 2.9 U/L (measured with mucin or sialyl lactose) in the incubation mixture.

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2

Khedri, Zahra, Yanhong Li, Hongzhi Cao, Jingyao Qu, Hai Yu, Musleh M. Muthana y Xi Chen. "Synthesis of selective inhibitors against V. cholerae sialidase and human cytosolic sialidase NEU2". Organic & Biomolecular Chemistry 10, n.º 30 (2012): 6112. http://dx.doi.org/10.1039/c2ob25335f.

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3

Dhanushkodi, Anandh y Michael P. McDonald. "Intracranial V. cholerae Sialidase Protects against Excitotoxic Neurodegeneration". PLoS ONE 6, n.º 12 (15 de diciembre de 2011): e29285. http://dx.doi.org/10.1371/journal.pone.0029285.

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4

Watson, Jacqueline N., Tara L. Knoll, Johnny H. Chen, Doug T. H. Chou, Thor J. Borgford y Andrew J. Bennet. "Use of conformationally restricted pyridinium α-D-N-acetylneuraminides to probe specificity in bacterial and viral sialidases". Biochemistry and Cell Biology 83, n.º 2 (1 de abril de 2005): 115–22. http://dx.doi.org/10.1139/o04-126.

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Investigations into subtle changes in the catalytic activity of sialidases have been performed using enzymes from several different origins, and their results have been compared. This work highlights the potential pitfalls encountered when extending conclusions derived from mechanistic studies on a single enzyme even to those with high-sequence homology. Specifically, a panel of 5 pyridinium N-acetylneuraminides were used as substrates in a study that revealed subtle differences in the catalytic mechanisms used by 4 different sialidase enzymes. The lowest reactivity towards the artificial (pyridinium) substrates was displayed by the Newcastle disease virus hemagglutinin-neuraminidase. Moreover, in reactions involving aryl N-acetylneuraminides, the activity of the Newcastle enzyme was competitively inhibited by the 3,4-dihydro-2H-pyrano[3,2-c]pyridinium compound with a Ki = 58 µmol/L. Alternatively, the 3 bacterial enzymes tested, from Salmonella typhimurium, Clostridium perfringens, and Vibrio cholerae, were catalytically active against all members of the panel of substrates. Based on the observed effect of leaving-group ability, it is proposed that the rate-determining step for kcat (and likely for kcat/Km as well) with each bacterial enzyme is as follows: sialylation, which is concerted with conformational change for V. cholerae; and conformational change for S. typhimurium and C. perfringens.Key words: sialidases, neuraminidases, sialic acids, glycosidase, mechanism.

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5

Chuenkova, M. y M. E. Pereira. "Trypanosoma cruzi trans-sialidase: enhancement of virulence in a murine model of Chagas' disease." Journal of Experimental Medicine 181, n.º 5 (1 de mayo de 1995): 1693–703. http://dx.doi.org/10.1084/jem.181.5.1693.

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Trypanosoma cruzi, the etiological agent of Chagas' disease, expresses a trans-sialidase at highest levels in infective trypomastigotes, where it attaches to the plasma membrane by a glycophosphoinositol linkage. Bound enzyme sheds into the extracellular milieu in a soluble form. Experiments performed in vitro suggest that the trans-sialidase participates in several parameters of T. cruzi-host interactions, like cell adhesion and complement resistance. However, the role that membrane-bound and soluble trans-sialidase plays in the infection of mammals is not understood. To begin to study the role the enzyme may play in vivo, T. cruzi trypomastigotes were inoculated subcutaneously into mice that had been sensitized for various times with the purified protein. A single dose of either endogenous or recombinant trans-sialidase injected into the connective tissues of BALB/c mice greatly enhanced parasitemia and mortality. Maximum enhancement was achieved with 1-2-h priming. Injection of the enzyme after the parasites had been established in the inoculation site had little, if any, consequence in modifying virulence. The enhancement did not seem to be through a direct effect of the enzyme on trypomastigote-host cell interactions because it occurred when the sites of trans-sialidase sensitization and parasite inoculation were physically separate. Rather, virulence enhancement seemed to depend on inflammatory cells, since priming with trans-sialidase had no significant effect in severe combined immunodeficiency mice, which lack functional T and B lymphocytes. However, antibody response to T. cruzi in the trans-sialidase-primed BALB/c mice was the same as in the control animals. Virulence enhancement was specific for the trans-sialidase because it did not occur in mice primed with Newcastle virus sialidase, which has the same substrate specificity as the T. cruzi enzyme, or with the sialidase from the bacterium Vibrio cholerae, whose substrate specificity is broader than the trypanosome sialidase. Furthermore, no enhancement of virulence occurred after sensitization with another adhesion protein (penetrin) purified from T. cruzi trypomastigotes and engineered bacteria, nor with bacterial lipopolysaccharide. The virulence-promoting activity of soluble trans-sialidase in the mouse model may be physiologically relevant because it was achieved with tiny doses, approximately 1-2 microgram/kg, raising the possibility that neutralization of the enzyme with specific probes could impair the development of Chagas' disease. In fact, a monoclonal antibody specific for the tandem repeat in the trans-sialidase COOH terminus enhanced infection of BALB/c mice, in agreement with earlier experiments in vitro, whereas antibodies against an amino acid sequence in the Cys region had the opposite effect.

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6

Slack, Teri J., Wanqing Li, Dashuang Shi, John B. McArthur, Gengxiang Zhao, Yanhong Li, An Xiao et al. "Triazole-linked transition state analogs as selective inhibitors against V. cholerae sialidase". Bioorganic & Medicinal Chemistry 26, n.º 21 (noviembre de 2018): 5751–57. http://dx.doi.org/10.1016/j.bmc.2018.10.028.

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7

Powell, L. D., S. W. Whiteheart y G. W. Hart. "Cell surface sialic acid influences tumor cell recognition in the mixed lymphocyte reaction." Journal of Immunology 139, n.º 1 (1 de julio de 1987): 262–70. http://dx.doi.org/10.4049/jimmunol.139.1.262.

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Abstract The Ia+ B cell lymphoma, AKTB-1b, fails to stimulate thymic lymphocytes in a one-way mixed lymphocyte reaction unless pretreated with sialidase or inhibitors of N-linked oligosaccharide processing. A comparison of different sialidases and sialyltransferases suggests that the removal of only a subset of total surface sialic acid, rather than net desialylation of the cell surface, is required. Three sialidases were compared, including Vibrio cholerae (VC) and Clostridium perfringens (CP), which will cleave alpha 2-3, alpha 2-6, and alpha 2-8, sialic acid linkages, and Newcastle Disease virus (NDV), which will remove only alpha 2-3 and alpha 2-8 linked sialic acid. When treated with equivalent units of sialidase, CP-, VC-, and NDV-treated cells were 24-fold, sixfold, and threefold better stimulators than untreated cells. In contrast, VC released 1.3-fold and 2.5-fold more sialic acid per cell than did CP or NDV, respectively. Furthermore, VC was superior in reducing the levels of binding of the sialic acid-specific lectin, Limulus polyphemus agglutinin, in exposing Gal beta 1-3GalNAc and Gal beta 1-4GlcNAc residues, and in desialylating gangliosides. Two-dimensional gel analysis indicated that VC and CP were both equal and superior to NDV in the desialylation of iodinatable cell-surface proteins, including H-2Kk, I-A beta k, and a highly sialylated 65,000 dalton protein of unknown identity. Maximal resialylation of CP-treated cells with exogenously added CMP-NANA and either the alpha 2-3(Gal beta 1-3GalNAc) or alpha 2-6(Gal beta 1-4GlcNAc) sialyltransferase did not reduce the stimulatory capacity of these cells. However, resialylation of VC-treated cells with just CMP-NANA alone resulted in 49% reversal of their stimulatory capacity, and no additional reversal could be achieved with either of the sialyltransferases. Although the alpha 2-6(Gal beta 1-4GlcNAc) sialyltransferase was capable of adding back approximately 10% of the sialic acid removed, the endogenous activity added back approximately 0.1% of the total sialic acid removed. SDS-PAGE gels of the sialylated cells indicated that the exogenously added sialyltransferase labeled many different proteins, whereas the endogenous activity labeled far fewer proteins, predominantly in 46,000 and 25,000 m.w. range. Both the desialylation and resialylation data suggest that the sialidase-dependent stimulation is due to the desialylation of specific membrane structures. Together with previous studies, these data suggest that the sialic acids involved are probably alpha 2-6 linked to N-linked glycosyl moieties.

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8

Mann, Maretta C., Robin J. Thomson, Jeffrey C. Dyason, Sarah McAtamney y Mark von Itzstein. "Modelling, synthesis and biological evaluation of novel glucuronide-based probes of Vibrio cholerae sialidase". Bioorganic & Medicinal Chemistry 14, n.º 5 (marzo de 2006): 1518–37. http://dx.doi.org/10.1016/j.bmc.2005.10.004.

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9

Wilson, Jennifer C., Robin J. Thomson, Jeffrey C. Dyason, Pas Florio, Kaylene J. Quelch, Samia Abo y Mark von Itzstein. "The design, synthesis and biological evaluation of neuraminic acid-based probes of Vibrio cholerae sialidase". Tetrahedron: Asymmetry 11, n.º 1 (enero de 2000): 53–73. http://dx.doi.org/10.1016/s0957-4166(99)00552-2.

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10

Wallimann, Kurt y Andrea Vasella. "Phosphonic-Acid Analogues of the N-Acetyl-2-deoxyneiiraniinic Acids: Synthesis and Inhibition ofVibrio cholerae Sialidase". Helvetica Chimica Acta 73, n.º 5 (8 de agosto de 1990): 1359–72. http://dx.doi.org/10.1002/hlca.19900730523.

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11

Mizan, Shaikh, Adam Henk, Amy Stallings, Marie Maier y Margie D. Lee. "Cloning and Characterization of Sialidases with 2-6′ and 2-3′ Sialyl Lactose Specificity from Pasteurella multocida". Journal of Bacteriology 182, n.º 24 (15 de diciembre de 2000): 6874–83. http://dx.doi.org/10.1128/jb.182.24.6874-6883.2000.

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ABSTRACT Pasteurella multocida is a mucosal pathogen that colonizes the respiratory system of susceptible hosts. Most isolates ofP. multocida produce sialidase activity, which may contribute to colonization of the respiratory tract or the production of lesions in an active infection. We have cloned and sequenced a sialidase gene, nanH, from a fowl cholera isolate ofP. multocida. Sequence analysis of NanH revealed that it exhibited significant amino acid sequence homology with many microbial sialidases. Insertional inactivation of nanH resulted in a mutant strain that was not deficient in sialidase production. However, this mutant exhibited reduced enzyme activity and growth rate on 2-3′ sialyl lactose compared to the wild type. Subsequently, we demonstrated the presence of two sialidases by cloning another sialidase gene that differed from nanH in DNA sequence and substrate specificity. NanB demonstrated activity on both 2-3′ and 2-6′ sialyl lactose, while NanH demonstrated activity only on 2-3′ sialyl lactose. Neither enzyme liberated sialic acid from colominic acid (2-8′ sialyl lactose). Recombinant E. coli containing the sialidase genes were able to utilize several sialoconjugants when they were provided as sole carbon sources in minimal medium. These data suggest that sialidases have a nutritional function and may contribute to the ability of P. multocida to colonize and persist on vertebrate mucosal surfaces.

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12

Vasella, Andrea y Ren� Wyler. "Synthesis of a Phosphonic Acid Analogue ofN-Acetyl-2,3-didehydro-2-deoxyneuraminic Acid, an Inhibitor ofVibrio cholerae Sialidase". Helvetica Chimica Acta 74, n.º 2 (13 de marzo de 1991): 451–63. http://dx.doi.org/10.1002/hlca.19910740223.

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13

WALLIMANN, K. y A. VASELLA. "ChemInform Abstract: C-Glycosides of N-Acetylneuraminic Acid. Synthesis and Investigation of Their Effect on Vibrio cholerae Sialidase." ChemInform 23, n.º 3 (22 de agosto de 2010): no. http://dx.doi.org/10.1002/chin.199203241.

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14

Schreiner, Erwin, Erich Zbiral, Reinhard G. Kleineidam y Roland Schauer. "2,3-Didehydro-2-deoxysialic acids structurally varied at C-5 and their behaviour towards the sialidase from Vibrio cholerae". Carbohydrate Research 216 (septiembre de 1992): 61–66. http://dx.doi.org/10.1016/0008-6215(92)84150-q.

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15

VASELLA, A. y R. WYLER. "ChemInform Abstract: Synthesis of a Phosphonic Acid Analogue of N-Acetyl-2,3-didehydro-2- deoxyneuraminic Acid, an Inhibitor of Vibrio cholerae Sialidase." ChemInform 22, n.º 21 (23 de agosto de 2010): no. http://dx.doi.org/10.1002/chin.199121270.

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16

Haselhorst, Thomas, Jennifer C. Wilson, Robin J. Thomson, Sarah McAtamney, John G. Menting, Ross L. Coppel y Mark von Itzstein. "Saturation transfer difference (STD) 1H-NMR experiments and in silico docking experiments to probe the binding of N-acetylneuraminic acid and derivatives to Vibrio cholerae sialidase". Proteins: Structure, Function, and Bioinformatics 56, n.º 2 (28 de abril de 2004): 346–53. http://dx.doi.org/10.1002/prot.20143.

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17

Zbiral, Erich, Erwin Schreiner, Rudolf Christian, Reinhard G. Kleineidam y Roland Schauer. "Structural Variations ofN-Acetylneuraminic Acid, 10. Synthesis of 2,7-, 2,8-, and 2,9-Dideoxy- and 2,4,7-Trideoxy-2,3-didehydro-N-acetylneuraminic Acids and Their Behavior Towards Sialidase fromVibrio cholerae". Liebigs Annalen der Chemie 1989, n.º 2 (10 de febrero de 1989): 159–65. http://dx.doi.org/10.1002/jlac.198919890131.

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18

Schreiner, Erwin, Erich Zbiral, Reinhard G. Kleineidam y Roland Schauer. "Structural Variations on N-acetylneuraminic acid, 20. Synthesis of some 2,3-didehydro-2-deoxysialic Acids structurally varied at C-4 and their behavior towards Sialidase from Vibrio cholerae". Liebigs Annalen der Chemie 1991, n.º 2 (12 de febrero de 1991): 129–34. http://dx.doi.org/10.1002/jlac.199119910124.

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19

Maliakal, Mathew A., Mepur H. Ravindranath, Reiko F. Irie y Donald L. Morton. "An improved method for the measurement of total lipid-bound sialic acids after cleavage of ?2,8 sialic acid linkage withVibrio cholerae sialidase in the presence of cholic acid, SDS and Ca2+". Glycoconjugate Journal 11, n.º 2 (abril de 1994): 97–104. http://dx.doi.org/10.1007/bf00731149.

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20

SCHREINER, E., E. ZBIRAL, R. G. KLEINEIDAM y R. SCHAUER. "ChemInform Abstract: Structural Variations on N-Acetylneuraminic Acid. Part 20. Synthesis of Some 2,3-Didehydro-2-deoxysialic Acids Structurally Varied at C-4 and Their Behavior Towards Sialidase from Vibrio cholerae." ChemInform 22, n.º 17 (23 de agosto de 2010): no. http://dx.doi.org/10.1002/chin.199117258.

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21

Lee, Youngjin, Young Bae Ryu, Hyung-Seop Youn, Jung Keun Cho, Young Min Kim, Ji-Young Park, Woo Song Lee, Ki Hun Park y Soo Hyun Eom. "Structural basis of sialidase in complex with geranylated flavonoids as potent natural inhibitors". Acta Crystallographica Section D Biological Crystallography 70, n.º 5 (30 de abril de 2014): 1357–65. http://dx.doi.org/10.1107/s1399004714002971.

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Sialidase catalyzes the removal of a terminal sialic acid from glycoconjugates and plays a pivotal role in nutrition, cellular interactions and pathogenesis mediating various infectious diseases including cholera, influenza and sepsis. An array of antiviral sialidase agents have been developed and are commercially available, such as zanamivir and oseltamivir for treating influenza. However, the development of bacterial sialidase inhibitors has been much less successful. Here, natural polyphenolic geranylated flavonoids which show significant inhibitory effects againstCp-NanI, a sialidase fromClostridium perfringens, are reported. This bacterium causes various gastrointestinal diseases. The crystal structure of theCp-NanI catalytic domain in complex with the best inhibitor, diplacone, is also presented. This structure explains how diplacone generates a stable enzyme–inhibitor complex. These results provide a structural framework for understanding the interaction between sialidase and natural flavonoids, which are promising scaffolds on which to discover new anti-sialidase agents.

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22

Masserini, M., P. Palestini, B. Venerando, A. Fiorilli, D. Acquotti y G. Tettamanti. "Interactions of proteins with ganglioside-enriched microdomains on the membrane: the lateral phase separation of molecular species of GD1a ganglioside, having homogeneous long-chain base composition, is recognized by Vibrio cholerae sialidase". Biochemistry 27, n.º 20 (4 de octubre de 1988): 7973–78. http://dx.doi.org/10.1021/bi00420a057.

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23

Zbiral, Erich, Hannelore H. Brandstetter, Rudolf Christian y Roland Schauere. "Structural Variations ofN-Acetylneuraminic Acid, 7. Synthesis of the C-7-, C-8-, and C-7,8-Side Chain Epimers of 2-Deoxy-2,3-didehydro-N-acetylneuraminic Acid and Their Behaviour Towards Sialidase fromVibrio cholerae". Liebigs Annalen der Chemie 1987, n.º 9 (14 de septiembre de 1987): 781–86. http://dx.doi.org/10.1002/jlac.198719870828.

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24

Spiegel, S., K. M. Yamada, B. E. Hom, J. Moss y P. H. Fishman. "Fibrillar organization of fibronectin is expressed coordinately with cell surface gangliosides in a variant murine fibroblast." Journal of Cell Biology 102, n.º 5 (1 de mayo de 1986): 1898–906. http://dx.doi.org/10.1083/jcb.102.5.1898.

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NCTC 2071A cells, a line of transformed murine fibroblasts, grow in serum-free medium, are deficient in gangliosides, synthesize fibronectin, but do not retain and organize it on the cell surface. When the cells are exposed to exogenous gangliosides, fibrillar strands of fibronectin become attached to the cell surface. A morphologically distinct variant of NCTC 2071A cells was observed to both retain cell surface fibronectin and organize it into a fibrillar network when the cells were stained with anti-fibronectin antibodies and a fluorescent second antibody. A revertant cell type appeared to resemble the parental NCTC 2071A cells in terms of morphology and fibronectin organization. All three cell types were subjected to mild NaIO4 oxidation and reduction with KB3H4 of very high specific radioactivity in order to label the sialic acid residues of surface gangliosides. The variant had much more surface gangliosides than the parental, particularly more complex gangliosides corresponding to GM1 and GD1a. The surface gangliosides of the revertant were intermediate between the parental and the variant. By using sialidase, which hydrolyzes GD1a to GM1, and 125I-labeled cholera toxin, which binds specifically to GM1, the identity and levels of these gangliosides were confirmed in the three cell types. When variant cells were exposed to sialidase for 2 d, there appeared to be little change in fibronectin organization. Concomitant treatment of the cells with the B subunit of cholera toxin, which bound to all the surface GM1 including that generated by the sialidase, however, eliminated the fibrillar network of fibronectin. In addition, exposure of the variant cells to a 70,000-mol-wt fragment of fibronectin, which lacks the cell attachment domain but contains a matrix assembly domain, inhibited the formation of fibers. Finally, all three cell types were assayed for their ability to attach to and spread on fibronectin-coated surfaces; no significant differences were found. Our results further establish that the ability of a cell to organize fibronectin into an extracellular matrix is dependent on certain gangliosides, but they also indicate that cell adhesion to fibronectin is independent of these gangliosides. We suggest that matrix organization and cell attachment and spreading are based on separate mechanisms and that these functions are associated with different cell surface "receptors."

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Zbiral, Erich, Erwin Schreiner, Mamikrao M. Salunkhe, Gerhard Schulz, Reinhard G. Kleineidam y Roland Schauer. "Structural Variations ofN-Acetylneuraminic Acid, 11, Synthesis of the 4-Methylumbelliferyl 2α-Glycosides of 7-Epi-, 8-Epi-, and 7,8-Bis(epi)-N-acetylneuraminic Acids, as well as of 7-Deoxy-, 8-Deoxy-, 9-Deoxy-, and 4,7-Dideoxy-N-acetylneuraminic Acids and Their Behaviour Towards Sialidase fromVibrio cholerae". Liebigs Annalen der Chemie 1989, n.º 6 (13 de junio de 1989): 519–26. http://dx.doi.org/10.1002/jlac.198919890192.

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26

Almeida, C. N., T. Q. Furian, K. A. Borges, G. Perdoncini, M. J. Mauel, S. L. S. Rocha, V. P. Nascimento, C. T. P. Salle y H. L. S. Moraes. "Assessment of FTA card employment for Pasteurella multocida DNA transport and detection of virulence-associated genes in strains isolated from fowl cholera in the United States". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 70, n.º 6 (diciembre de 2018): 1855–61. http://dx.doi.org/10.1590/1678-4162-9821.

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ABSTRACT Fowl Cholera (FC) is a disease caused by Pasteurella multocida. The severity of this disease is partly caused by virulence factors. Genes encoding fimbriae, capsule, sialidases and proteins for iron metabolism may be related to P. multocida’s ability to infect the host. Besides to examining DNA for the presence of virulence genes, DNA is essential for the diagnostic and FTA cards are an alternative for genetic material transport. The study aims to evaluate the viability of P. multocida DNA transport using the cards and to detect 14 virulence genes in 27 strains isolated from FC cases in the United States by multiplex-PCR. No growth was observed in any of the FTA cards, which was essential to assess the security. Furthermore, DNA detection was possible in 100% of the samples, independent of the storage period (7 to 35 days) and temperature (4°C and 37°C). ptfA, exbd-tonB, hgbA, nanB, oma87, hyaD-hyaC, sodC, hgbB, sodA, nanH and pfhA genes were detected in more than 80% of the samples. FTA cards have proven to be a viable and safe tool for DNA transport of P. multocida. A majority of genes showed a high frequency, which was similar to strains isolated from FC cases.

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27

Kaisar, M. Hasanul, Mohammed Saruar Bhuiyan, Aklima Akter, Danial Saleem, Anita S. Iyer, Pinki Dash, Al Hakim et al. "Vibrio cholerae Sialidase-Specific Immune Responses Are Associated with Protection against Cholera". mSphere 6, n.º 2 (28 de abril de 2021). http://dx.doi.org/10.1128/msphere.01232-20.

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ABSTRACT Cholera remains a major public health problem in resource-limited countries. Vaccination is an important strategy to prevent cholera, but currently available vaccines provide only 3 to 5 years of protection. Understanding immune responses to cholera antigens in naturally infected individuals may elucidate which of these are key to longer-term protection seen following infection. We recently identified Vibrio cholerae O1 sialidase, a neuraminidase that facilitates binding of cholera toxin to intestinal epithelial cells, as immunogenic following infection in two recent high-throughput screens. Here, we present systemic, mucosal, and memory immune responses to sialidase in cholera index cases and evaluated whether systemic responses to sialidase correlated with protection using a cohort of household contacts. Overall, we found age-related differences in antisialidase immune response following cholera. Adults developed significant plasma anti-sialidase IgA, IgG, and IgM responses following infection, whereas older children (≥5 years) developed both IgG and IgM responses, and younger children only developed IgM responses. Neither older children nor younger children had a rise in IgA responses over the convalescent phase of infection (day 7/day 30). On evaluation of mucosal responses and memory B-cell responses to sialidase, we found adults developed IgA antibody-secreting cell (ASC) and memory B-cell responses. Finally, in household contacts, the presence of serum anti-sialidase IgA, IgG, and IgM antibodies at enrollment was associated with a decrease in the risk of subsequent infection. These data show cholera patients develop age-related immune responses against sialidase and suggest that immune responses that target sialidase may contribute to protective immunity against cholera. IMPORTANCE Cholera infection can result in severe dehydration that may lead to death within a short period of time if not treated immediately. Vaccination is an important strategy to prevent the disease. Oral cholera vaccines provide 3 to 5 years of protection, with 60% protective efficacy, while natural infection provides longer-term protection than vaccination. Understanding the immune responses after natural infection is important to better understand immune responses to antigens that mediate longer-term protection. Sialidase is a neuraminidase that facilitates binding of cholera toxin to intestinal epithelial cells. We show here that patients with cholera develop systemic, mucosal, and memory B-cell immune responses to the sialidase antigen of Vibrio cholerae O1 and that plasma responses targeting this antigen correlate with protection.

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28

Chowdhury, Fahima, Afroza Akter, Taufiqur Rahman Bhuiyan, Rajib Biswas, Md Golam Firoj, Imam Tauheed, Jason B. Harris et al. "Long-term sialidase-specific immune responses after natural infection with cholera: Findings from a longitudinal cohort study in Bangladesh". Frontiers in Immunology 13 (22 de diciembre de 2022). http://dx.doi.org/10.3389/fimmu.2022.1067737.

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BackgroundImmune responses that target sialidase occur following natural cholera and have been associated with protection against cholera. Sialidase is a neuraminidase that facilitates the binding of cholera toxin (CT) to intestinal epithelial cells. Despite this, little is known about age-related sialidase-specific immune responses and the impact of nutritional status and co-infection on sialidase-specific immunity.MethodsWe enrolled 50 culture-confirmed Vibrio cholerae O1 cholera cases presenting to the icddr,b Dhaka hospital with moderate to severe dehydration. We evaluated antibody responses out to 18 months (day 540) following cholera. We assessed immune responses targeting sialidase, lipopolysaccharide (LPS), cholera toxin B subunit (CtxB), and vibriocidal responses. We also explored the association of sialidase-specific immune responses to nutritional parameters and parasitic co-infection of cases.ResultsThis longitudinal cohort study showed age-dependent differences in anti-sialidase immune response after natural cholera infection. Adult patients developed plasma anti-sialidase IgA and IgG responses after acute infection (P<0.05), which gradually decreased from day 30 on. In children, no significant anti-sialidase IgA, IgM, and IgG response was seen with the exception of a late IgG response at study day 540 (p=0.05 compared to adults). There was a correlation between anti-sialidase IgA with vibriocidal titers, as well as anti-sialidase IgA and IgG with anti-LPS and anti-CtxB antibody responses in adult patients, whereas in children, a significant positive correlation was seen only between anti-sialidase IgA and CtxB IgA responses. Stunted children showed significantly lower anti-sialidase IgA, IgG, and IgM antibody responses and higher LPS IgG and IgM antibody responses than healthy children. The anti-sialidase IgA and IgG responses were significantly higher in cases with concomitant parasitic infection.ConclusionOur data suggest that cholera patients develop age-distinct systemic and mucosal immune responses against sialidase. The stunted children have a lower anti-sialidase antibody response which may be associated with gut enteropathy and the neuraminidase plays an important role in augmented immune response in cholera patients infected with parasites.

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Upadhyay, Ipshita, Siqi Li, Galen Ptacek, Hyesuk Seo, David A. Sack y Weiping Zhang. "A polyvalent multiepitope protein cross-protects against Vibrio cholerae infection in rabbit colonization and passive protection models". Proceedings of the National Academy of Sciences 119, n.º 50 (5 de diciembre de 2022). http://dx.doi.org/10.1073/pnas.2202938119.

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Using epitope- and structure-based multiepitope fusion antigen vaccinology platform, we constructed a polyvalent protein immunogen that presents antigenic domains (epitopes) of Vibrio cholerae toxin-coregulated pilus A, cholera toxin (CT), sialidase, hemolysin A, flagellins (B, C, and D), and peptides mimicking lipopolysaccharide O-antigen on a flagellin B backbone. Mice and rabbits immunized intramuscularly with this polyvalent protein immunogen developed antibodies to all of the virulence factors targeted by the immunogen except lipopolysaccharide. Mouse and rabbit antibodies exhibited functional activities against CT enterotoxicity, CT binding to GM 1 ganglioside, bacterial motility, and in vitro adherence of V. cholerae O1, O139, and non-O1/non-O139 serogroup strains. When challenged orogastrically with V. cholerae O1 El Tor N16961 or a non-O1/non-O139 strain, rabbits IM immunized with the immunogen showed a 2-log (99%) reduction in V. cholerae colonization of small intestines. Moreover, infant rabbits born to the mother immunized with the protein immunogen acquired antibodies passively and were protected from bacterial intestinal colonization (>2-log reduction), severe diarrhea (100%), and mild diarrhea (88%) after infection with V. cholerae O1 El Tor (N16961), O1 classical (O395), O139 (Bengal), or a non-O1/non-O139 strain. This study demonstrated that this polyvalent cholera protein is broadly immunogenic and cross-protective, and an adult rabbit colonization model and an infant rabbit passive protection model fill a gap in preclinical efficacy assessment in cholera vaccine development.

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Kauffman, Robert C., Taufiqur R. Bhuiyan, Rie Nakajima, Leslie M. Mayo-Smith, Rasheduzzaman Rashu, Mohammad Rubel Hoq, Fahima Chowdhury et al. "Single-Cell Analysis of the Plasmablast Response to Vibrio cholerae Demonstrates Expansion of Cross-Reactive Memory B Cells". mBio 7, n.º 6 (20 de diciembre de 2016). http://dx.doi.org/10.1128/mbio.02021-16.

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ABSTRACT We characterized the acute B cell response in adults with cholera by analyzing the repertoire, specificity, and functional characteristics of 138 monoclonal antibodies (MAbs) generated from single-cell-sorted plasmablasts. We found that the cholera-induced responses were characterized by high levels of somatic hypermutation and large clonal expansions. A majority of the expansions targeted cholera toxin (CT) or lipopolysaccharide (LPS). Using a novel proteomics approach, we were able to identify sialidase as another major antigen targeted by the antibody response to Vibrio cholerae infection. Antitoxin MAbs targeted both the A and B subunits, and most were also potent neutralizers of enterotoxigenic Escherichia coli heat-labile toxin. LPS-specific MAbs uniformly targeted the O-specific polysaccharide, with no detectable responses to either the core or the lipid moiety of LPS. Interestingly, the LPS-specific antibodies varied widely in serotype specificity and functional characteristics. One participant infected with the Ogawa serotype produced highly mutated LPS-specific antibodies that preferentially bound the previously circulating Inaba serotype. This demonstrates durable memory against a polysaccharide antigen presented at the mucosal surface and provides a mechanism for the long-term, partial heterotypic immunity seen following cholera. IMPORTANCE Cholera is a diarrheal disease that results in significant mortality. While oral cholera vaccines are beneficial, they do not achieve equivalent protection compared to infection with Vibrio cholerae . Although antibodies likely mediate protection, the mechanisms of immunity following cholera are poorly understood, and a detailed understanding of antibody responses to cholera is of significance for human health. In this study, we characterized the human response to cholera at the single-plasmablast, monoclonal antibody level. Although this approach has not been widely applied to the study of human bacterial infection, we were able to uncover the basis of cross-reactivity between different V. cholerae serotypes and the likely impact of prior enterotoxigenic Escherichia coli exposure on the response to cholera, as well as identify novel antigenic targets. In addition to improving our understanding of the repertoire and function of the antibody response to cholera in humans, this study has implications for future cholera vaccination efforts.

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Asang, Gogula Selvi, Shadariah Mamat, Nadiawati Alias y Asmad Kari. "Expression and characterization of family 40 Carbohydrate Binding Module (CBM) from Vibrio cholerae Non-O1 sialidase". Asia Pacific Journal of Molecular Biology and Biotechnology, 29 de octubre de 2020, 26–38. http://dx.doi.org/10.35118/apjmbb.2020.028.4.03.

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Carbohydrate Binding Module (CBM) is a non-catalytic protein domain found in carbohydrate-active enzyme (glycoside hydrolase) and its role is to bring carbohydrates in close proximity to the enzyme catalytic site for complete hydrolysis. The removal of this CBM from most protein domains often leads to reduced enzyme activity and efficiency. In this study, a gene encoding for family 40 CBM from Vibrio cholerae Non-O1 sialidase was cloned and successfully expressed in E. coli BL21 (DE3) strain. The CBM40 encoded 195 amino acids with 585 bp of nucleotide sequence. The protein was successfully expressed at 18°C when induced with 1 mM IPTG. Maximum expression was achieved at 20 hours after post-induction time. For purification of the protein, an anionic denaturing detergent method was used containing 1% SDS and 0.1% sarkosyl with gradient affinity elution at 50 mM imidazole concentrations. SDS-PAGE analysis of the purified CBM40 protein displayed a protein band with a molecular mass of 21 kDa. Protein characterization showed optimum stability in 100 mM citrate buffer pH 5.5, with the highest Tm value of 40 °C. The protein was stable between pH 5.5–6.2 and able to retain its activity at 27–56°C. The addition of Mn2+ and Mg2+ increased the protein melting temperature to 56°C. Meanwhile, the addition of reagents, such as 1% SDS and 1 M urea increased the protein melting temperature (Tm) to approximately 55°C. Protein stability can be influenced by many factors, including different buffers, pHs, temperatures, ionic strengths, and chemical reagents used in a study. The optimum characterization conditions established would further lead to the discovery of CBM40 protein true potential in enhancing substrate binding affinity and protein-carbohydrate recognition, which underpins its broad applications in biotechnology and protein engineering fields.

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WALLIMANN, K. y A. VASELLA. "ChemInform Abstract: Phosphonic-Acid Analogues of the N-Acetyl-2-deoxyneuraminic Acids: Synthesis and Inhibition of Vibrio cholerae Sialidase." ChemInform 21, n.º 48 (27 de noviembre de 1990). http://dx.doi.org/10.1002/chin.199048271.

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ZBIRAL, E., E. SCHREINER, R. CHRISTIAN, R. G. KLEINEIDAM y R. SCHAUER. "ChemInform Abstract: Structural Variations of N-Acetylneuraminic Acid. Part 10. Synthesis of 2,7-, 2,8-, and 2,9-Dideoxy- and 2,4,7-Trideoxy-2,3-didehydro-N-acetylneuraminic Acids and Their Behavior Toward Sialidase from Vibrio cholerae." ChemInform 20, n.º 19 (9 de mayo de 1989). http://dx.doi.org/10.1002/chin.198919288.

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ZBIRAL, E., H. H. BRANDSTETTER, R. CHRISTIAN y R. SCHAUER. "ChemInform Abstract: Structural Variations of N-Acetylneuraminic Acid. Part 7. Synthesis of the C-7-, C-8-, and C-7,8 Side Chain Epimers of 2-Deoxy-2,3-didehydro-N-acetylneuraminic Acid and Their Behavior Towards Sialidase from Vibrio cholerae." ChemInform 18, n.º 49 (8 de diciembre de 1987). http://dx.doi.org/10.1002/chin.198749326.

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