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M E Reyes

Publications and source records attributed to M E Reyes.

9 recordsLinked to original sources
PubMed2000

Membrane vesicles released by Actinobacillus pleuropneumoniae contain proteases and Apx toxins.

Actinobacillus pleuropneumoniae serotype 1 releases vesicles containing proteases and Apx toxins into the culture medium. Vesicles were concentrated by ultracentrifugation and analyzed by electron microscopy and electrophoresis; their size ranged from 20 to 200 nm. A polyclonal antiserum raised against a purified high molecular mass secreted protease of serotype 1 recognized this protease on the surface of the vesicles by immunogold electron microscopy. Higher molecular mass polypeptides from vesicle extracts were recognized by the antiserum by Western immunoblot, indicating that the protease could form oligomers. However, these oligomers were not active against gelatin until secreted. Additionally, Apx toxins were also present in vesicles, and were recognized by Western immunoblot by an anti-serotype 1 toxins polyclonal serum. A. pleuropneumoniae antigens in vesicles were recognized by convalescent-phase pig sera from animals infected with serotype 1 or 5. The release of vesicles containing virulence factors could be a tissue damage mechanism in swine pleuropneumonia.

Actinobacillus pleuropneumoniae↗
PubMed1998

Transposon tagging of the Defective embryo and meristems gene of tomato.

The shoot and root apical meristems (SAMs and RAMs, respectively) of higher plants are mechanistically and structurally similar. This has led previously to the suggestion that the SAM and RAM represent modifications of a fundamentally homologous plan of organization. Despite recent interest in plant development, especially in the areas of meristem regulation, genes specifically required for the function of both the SAM and RAM have not yet been identified. Here, we report on a novel gene, Defective embryo and meristems (Dem), of tomato. This gene is required for the correct organization of shoot apical tissues of developing embryos, SAM development, and correct cell division patterns and meristem maintenance in roots. Dem was cloned using transposon tagging and shown to encode a novel protein of 72 kD with significant homology to YNV2, a protein of unknown function of Saccharomyces cerevisiae. Dem is expressed in root and shoot meristems and organ primordia but not in callus. The expression pattern of Dem mRNA in combination with the dem mutant phenotype suggests that Dem plays an important role within apical meristems.

Amino Acid Sequence↗
PubMed1998

Purification and characterization of a protease from Actinobacillus pleuropneumoniae serotype 1, an antigen common to all the serotypes.

A high molecular-mass proteolytic enzyme of Actinobacillus pleuropneumoniae serotype 1, was purified from culture supernatants (CSN) by using DEAE-cellulose and sepharose-4B-gelatin chromatography. In 10% SDS-polyacrylamide gels copolymerized with porcine gelatin, the protease showed a single band of activity of > 200 kDa. However, minor molecular-mass proteolytic bands were observed when the protease was electrophoresed in the presence of either 5% beta-mercaptoethanol, 50 mM dithiothreitol, or 0.25 M urea. Furthermore, when the > 200-kDa purified protein was passed through a sucrose gradient, several bands with proteolytic activity were found: 62, 90, 190, and 540 kDa. The proteolytic activity was increased in the presence of calcium or zinc and was not affected after being heated at 90 degrees C for 5 min. Proteolytic activities were also observed in CSN from all A. pleuropneumoniae serotypes and biotypes. The purified protease hydrolyzed porcine IgA and IgG in vitro. In addition, by immunoblot the protease was recognized by serum of naturally infected pigs with serotypes 1 and 5, and by serum of pigs experimentally infected with serotypes 1, 2, 8, or 9. Serum of a pig vaccinated with CSN of a serotype 3 strain also recognized the protease, but not sera of pigs vaccinated with a bacterin (serotype 1). Proteins from CSN of all the serotypes, which were precipitated with 70% (NH4)2SO4, were recognized by a polyclonal antibody raised against the purified protease. Taken together these results indicate that an antigenic protease is produced in vivo by all the serotypes of A. pleuropneumoniae. The results indicate that proteases could have a role in the disease and in the immune response of pigs infected with A. pleuropneumoniae.

Actinobacillus pleuropneumoniae↗
PubMed1996

Comparison of the cervical cytology test using the PAPNET method and conventional microscopy.

From August 1994 to June 1995, laboratories in 28 Mexican states and the Federal District submitted a total of 10098 diagnosed Pap test slides to Mexico's National Institute of Epidemiologic Diagnosis and Reference (INDRE) for reexamination by conventional methods and also by the automated PAPNET system in Suffern, New York, U.S.A. The aim was to determine the degree of agreement obtained by these various methods. Most of the slides examined (at least 78%) yielded negative results or merely indicated an inflammatory process; 8% to 14% indicated mild or moderate cervical dysplasia; and 2% to 3% indicated conditions ranging from severe dysplasia to invasive cervical cancer. Comparison of the state laboratory and INDRE diagnoses yielded a Kappa correlation coefficient of 0.62, near the lower limit of agreement, the agreement being poorest in cases where it was necessary to distinguish between degrees of abnormality. Although state laboratory underestimation appeared lowest with respect to cases of atypia and of mild, moderate, and severe dysplasia (between 12% and 20%), these percentages are alarming because it is at these stages that the patient may be treated to prevent evolution to carcinoma. While the Kappa correlation coefficient was better (0.80) when the INDRE and PAPNET diagnoses were compared, PAPNET showed only limited ability to distinguish between various pathologic alterations, and the percentages of underestimates (false negatives) obtained with PAPNET were also high. Overall, the results indicate a need to improve the quality of cervical cytology diagnoses at state public health laboratories in Mexico through stepped-up training and supervision. They also indicate that the use of PAPNET involves greater difficulty than does manual microscopic examination of cervical smears, and that a way still needs to be found to detect and review the false negative results generated by PAPNET before approving use of this technology.

Adolescent↗
PubMed1994

Blood levels in macular cystoid spaces and their relationship to retinal vein obstruction.

BACKGROUND: Blood levels in macular cystoid spaces are commonly seen in patients with branch or central retinal vein obstruction, but have not been previously reported. METHODS: To determine blood levels in cystoid spaces, a retrospective study was conducted of 102 eyes with branch retinal vein obstruction, 54 eyes with central retinal vein obstruction, 207 eyes with clinically significant diabetic macular edema, and 109 eyes with aphakic or pseudophakic cystoid macular edema seen over a 5-year period. RESULTS: Definite blood levels in cystoid spaces were found in 26 eyes (25%) with branch vein obstruction and in 4 eyes (8%) with central vein obstruction. In contrast, this clinical change was detected in only 1 of 207 eyes (1%) with diabetic cystoid macular edema, and in only 2 of 109 eyes (2%) with aphakic or pseudophakic cystoid macular edema (P < 0.001). When blood levels in cystoid spaces were detected in patients with branch vein obstruction, the site of obstruction tended to be superotemporal (P < 0.05). CONCLUSION: Blood levels in cystoid spaces are an important sign of retinal vein obstruction, and may help establish the diagnosis in certain cases.

Adult↗