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Biomedical subjects

M Wallach

Publications and source records attributed to M Wallach.

8 recordsLinked to original sources
PubMed1992

Homology of a vesicular amine transporter to a gene conferring resistance to 1-methyl-4-phenylpyridinium.

The vesicular amine transporter (VAT) catalyzes transport and storage of catechol and indolamines into subcellular organelles in a wide variety of cells. It plays a central role in neurotransmission and is the primary target for several pharmacological agents. One of the drugs, reserpine, binds very tightly to the transporter and remains bound even after solubilization, a finding that has proven useful for purification of the transporter from bovine adrenal medulla in a fully functional state. The sequences of 26 N-terminal amino acids and of an additional 7-amino acid internal peptide are presented. Antibodies against a synthetic peptide based on the above sequences immunoprecipitate the transporter, confirming the conclusion that the peptide sequence is derived from bovine VAT. To our knowledge, documentation of sequences of vesicular neurotransmitter transporters has not been presented previously. In addition, the sequences obtained are highly homologous to the predicted sequence of a protein from PC12 cells that confers to Chinese hamster ovary cells resistance to 1-methyl-4-phenylpyridinium (MPP+), an agent that causes parkinsonism in model systems, confirming the hypothesis that the protein conferring resistance to MPP+ is a VAT.

1-Methyl-4-phenylpyridinium↗
PubMed1992

Developmental gene expression of a 230-kilodalton macrogamete-specific protein of the avian coccidial parasite, Eimeria maxima.

We prepared a cDNA library from gametocytes of Eimeria maxima and screened it using antibodies raised against an 82-kDa gametocyte antigen. One cDNA clone designated pEM230 was isolated and characterized. It encodes a portion of a 230-kDa gametocyte protein and its DNA sequence shows the presence of several tandem repeats of 42 bp. In order to determine the stage and sex specificity of the mRNA for the 230-kDa protein, Northern blotting and in situ hybridization studies were performed. The 230-kDa protein is encoded for by a 7 kb mRNA, which is expressed exclusively during the macrogamete stage with no detectable expression seen in any other stage of parasite development.

Amino Acid Sequence↗
PubMed1992

Maternal immunization with gametocyte antigens as a means of providing protective immunity against Eimeria maxima in chickens.

In the present study, we wished to demonstrate the ability of surface gametocyte antigens to induce protective immunity against Eimeria maxima infections in chickens. In order to accomplish this goal, we employed maternal immunization as a means of providing large amounts of specific antibodies to offspring chicks. Upon challenge with sporulated E. maxima oocysts, chicks from hens immunized with affinity-purified gametocyte antigens showed greatly reduced oocyst production compared with chicks from sham-immunized hens. These results suggest that maternal immunization with gametocyte antigens can be used as a means to provide transmission-blocking immunity against E. maxima infections.

Animals↗
PubMed1990

Passive immunization of chickens against Eimeria maxima infection with a monoclonal antibody developed against a gametocyte antigen.

Eimeria maxima gametocytes contain two major antigens with molecular masses of 56 and 82 kilodaltons (kDa) which are recognized by convalescent sera from immune chickens. Preparations enriched in these two antigens were used to immunize mice, and several monoclonal antibodies which specifically reacted with the 56-kDa antigen were produced. One of these monoclonal antibodies of the immunoglobulin M subclass, along with immune chicken sera raised against affinity-purified 56- and 82-kDa antigens, was used to passively immunize chicks. On the basis of the parameter of total oocyst output, it was found that these antibodies provided partial protection (40 to 50% inhibition) against E. maxima challenge infections.

Animals↗
PubMed1989

Antigenic proteins of Eimeria maxima gametocytes: cell-free translation and detection with recovered chicken serum.

RNA was extracted from isolated Eimeria maxima gametocytes and translated in a rabbit reticulocyte cell-free protein synthesis system. The major cell-free translation products from E. maxima gametocyte RNA ranged from 225 to 50 kDa, distinct and different from uninfected chicken intestine cell-free translation products. Rabbit antiserum to E. maxima gametocytes as well as recovered chicken sera specifically precipitated some of the major gametocyte cell-free products. A time course of infected intestine RNA indicated that these cell-free synthesized gametocyte antigens appear at 130 to 138 hr postinfection.

Animals↗
PubMed1989

Eimeria maxima: isolation of gametocytes and their immunogenicity in mice, rabbits, and chickens.

Eimeria maxima gametocytes were isolated from infected chicken intestinal tissue by treatment with hyaluronidase and subsequent filtration through polymon filters. The isolated gametocytes were analyzed by microscopical and biochemical methods and shown to be highly enriched. The antigenicity of the gametocytes was analyzed in mice, rabbits, and chickens by ELISA and indirect immunofluorescence. Contrary to published results, we have found gametocytes to be highly immunogenic in all animals tested.

Animals↗