Browsing by Author "YUDELEVICH, A"

Now showing 1 - 9 of 9
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    DEOXYRIBONUCLEIC-ACID POLYMERASE FROM THE MARINE PSEUDOMONAS SP BAL-31
    (1980) VICUNA, R; VALDES, F; MEDINA, A; YUDELEVICH, A
    A DNA-dependent DNA polymerase (DNA nucleotidyltransferase) was purified 3000-fold from the marine Pseudomonas sp. BAL-31. The MW of the native enzyme was estimated by glycerol gradient sedimentation to be 110,000. The enzyme migrated in sodium dodecyl sulfate-acrylamide gels as a single polypeptide with a MW of 105,000. An absolute requirement for divalent cation was satisfied by Mg2+ or Mn2+ at concentrations of 1 mM. Monovalent cations at concentrations higher than 50 mM showed an inhibitory effect. The polymerase activity was resistant to N-ethylmaleimide and showed a wide pH optimum.
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    DEVELOPMENT OF HIGHLY SPECIFIC MONOCLONAL-ANTIBODIES FOR THE DIAGNOSIS OF VIBRIO-CHOLERAE-01
    (1995) CASTILLO, L; CASTILLO, D; SILVA, W; ZAPATA, L; REID, M; ULLOA, MT; SEOANE, M; MALDONADO, A; VALENZUELA, ME; BUSTOS, R; TAMPLIN, ML; MARTINEZ, MA; DEIOANNES, AE; JAMETT, A; YUDELEVICH, A; BECKER, MI
    We report here the development of two monoclonal antibodies, termed 5G8 and 5C12, belonging to the IgM and IgG(1) class, respectively, suitable for the identification of Vibrio cholerae 01 in clinical and environmental samples. The specificities of the monoclonals were evaluated by ELISA and indirect immunofluorescent microscopy of microorganisms normally present in stool samples and with two bacterial panels. One panel included 72 potentially antigenically related bacterial strains and the second panel included 20 pathogenic bacterial strains involved in diarrhea cases. The results of these extensive analyses indicate that monoclonal antibodies 5G8 and 5C12 are highly specific and suitable for the clinical diagnosis of Vibrio cholerae 01 inhuman stool samples by indirect immunofluorescent microscopy. Although the antigenic sites recognized by these antibodies were not identified in this study, the observation of Western blot patterns suggested that 5G8 and 5C12 monoclonal antibodies bind to LPS epitopes, a good structural marker for the detection of V. cholerae 01 because it is present in all bacterial cell walls.
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    ENTEROPATHOGENICITY OF AEROMONAS SPECIES ISOLATED FROM INFANTS - A COHORT STUDY
    (1988) FIGUEROA, G; GALENO, H; SOTO, V; TRONCOSO, M; HINRICHSEN, V; YUDELEVICH, A
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    MOLECULAR-CLONING AND EXPRESSION IN ESCHERICHIA-COLI OF A SALMONELLA-TYPHI PORIN GENE
    (1988) ZAROR, I; GOMEZ, I; CASTILLO, G; YUDELEVICH, A; VENEGAS, A
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    PHYSICAL CHARACTERIZATION OF A PLASMID (PTT1) ISOLATED FROM THERMUS THERMOPHILUS
    (1981) EBERHARD, MD; VASQUEZ, C; VALENZUELA, P; VICUNA, R; YUDELEVICH, A
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    RAPID PROCEDURE FOR PURIFYING A RESTRICTION ENDONUCLEASE FROM THERMUS-THERMOPHILUS (TTH I)
    (1980) VENEGAS, A; VICUNA, R; ALONSO, A; VALDES, F; YUDELEVICH, A
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    RESPIRATORY SYNCYTIAL VIRUS DETECTION BY DOT BLOT HYBRIDIZATION WITH A NONRADIOACTIVE SYNTHETIC OLIGODEOXYNUCLEOTIDE PROBE
    (1992) HERNANDEZ, O; FERNANDEZ, J; VALENZUELA, S; SANDINO, AM; PIZARRO, J; VASQUEZ, M; YUDELEVICH, A; SPENCER, E
    A synthetic oligodeoxynucleotide corresponding to a region of the nucleocapside gene (N) of respiratory syncytial virus (RSV), was used as a DNA probe to develop a nonradioactive hybridization assay for the detection of RSV. The probe was labeled by incorporation of biotin-7-dATP to the 3' end by a reaction catalyzed by terminal deoxynucleotydil transferase.
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    ROLE OF POLYMERIC FORMS OF THE BACTERIOPHAGE-PHI-X174 CODED GENE A-PROTEIN IN PHI-XRFI DNA CLEAVAGE
    (1979) IKEDA, JE; YUDELEVICH, A; SHIMAMOTO, N; HURWITZ, J
    Gene A of the .vphi.X174 genome codes for 2 proteins, A and A* of MW 60,000 and 35,000, respectively. The .vphi.X A* protein is formed from a natural internal initiator site within the A gene cistron while the .vphi.X A protein is the product of the entire A gene. These 2 proteins were purified to homogeneity as judged by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Previous studies showed that the .vphi.X A protein is an endonuclease which specifically introduces a discontinuity in the A cistron of the viral strand of supertwisted .vphi.XRF[replicative form]I DNA. In addition to this activity, the .vphi.X A protein also causes relaxation of supertwisted .vphi.XRFI DNA and formation of a .vphi.XRFII DNA .cntdot. .vphi.X A protein complex which has a discontinuity in the A cistron of the viral strand. This isolatable complex supports DNA synthesis when supplemented with extracts of uninfected Escherichia coli which lack .vphi.X A protein and .vphi.XRFI DNA. The .vphi.XRFII DNA .cntdot. .vphi.X A protein complex can be attacked by exonuclease III but is not susceptible to attack by E. coli DNA polymerase I, indicating that the 5''-end of the complex is blocked. Attempts to seal the RFII structure generated from the .vphi.XRFII DNA .cntdot. .vphi.X A protein complex with [phage] T4 DNA ligase in the presence or absence of DNA polymerase were unsuccessful. The .vphi.X A protein does not act catalytically in the cleavage of .vphi.XRFI DNA. Under conditions leading to the quantitative cleavage of .vphi.XRFI DNA, the molar ratio of .vphi.XRFI DNA to added .vphi.X A protein was approximately 1:10. At this molar ratio, cross-linking experiments with dimethyl suberimidate yielded 10 distinct protein bands which were multiples of the monomeric .vphi.X A protein. In the absence of DNA or in the presence of inactive DNA (.vphi.XRFII DNA) no distinct protein bands above a trimer were detected. It is possible in vitro to form a .vphi.XRFII DNA .cntdot. .vphi.X A protein complex with wild-type .vphi.XRFI DNA (.vphi.X A gene+) and with .vphi.XRFI DNA isolated from E. coli (su+) infected with phage .vphi.X H90 (an am mutant in the .vphi.X A gene). Thus, in vitro, in contrast to in vivo studies, .vphi.X A protein is not a cis acting protein. The purified .vphi.X A* protein does not substitute for the .vphi.X A protein in in vitro replication of .vphi.XRFI DNA nor does it interfere with the action of the .vphi.X A protein which binds only to supertwisted .vphi.XRFI DNA. In contrast, the .vphi.X A* protein binds to all duplex DNA preparations tested. This property prevents nucleases of E. coli from hydrolyzing duplex DNA to small MW products.
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    ROTAVIRUS DETECTION BY DOT BLOT HYBRIDIZATION ASSAY USING A NONRADIOACTIVE SYNTHETIC OLIGODEOXYNUCLEOTIDE PROBE
    (1992) FERNANDEZ, J; SANDINO, A; YUDELEVICH, A; AVENDANO, LF; VENEGAS, A; HINRICHSEN, V; SPENCER, E
    A synthetic oligodeoxynucleotide of 40 nucleotides corresponding to nucleotides 33-72 of the gene coding for the viral protein VP7 of rotavirus. was used as a nucleic acid probe to develop a non-radioactive hybridization method for rotavirus detection. The probe was labelled at the 3' end with biotin-7-dATP. The sensitivity and specificity of the dot blot hybridization assay for rotavirus detection was evaluated with 303 stool specimens. The results indicate that the hybridization assay has a higher sensitivity than both PAGE and EIA. Among the rotavirus strains tested 37 different electropherotypes were found. The results suggest that rotavirus diagnosis by dot hybridization using a non-radioactive probe may become routine laboratory procedure because it is simple, highly specific and very sensitive.