PubMed Health⌕ Search

Biomedical subjects

R Crameri

Publications and source records attributed to R Crameri.

99 records · Page 6Linked to original sources
PubMed1982

Secretion of tyrosinase in Streptomyces glaucescens.

In Streptomyces glaucescens, the intracellular and the extracellular enzyme forms of tyrosinase were found to be indentical in molecular weight (29 000), in copper content (0.21%), in the 19 amino acids at the amino-terminal end and in the ratio of cresolase to catecholase activity (0,005). The tyrosinase secretion process exhibited a constant rate of 0.15 units h-1 (mg protein)-1. Under highly induced conditions intracellular tyrosinase was accumulated. Mutations responsible for the non-melanogenic, tyrosinase-positive non-secretor mutant type are located chromosomally on the upper right arc of the S. glaucescens map near the ade-1 marker.

Catechol Oxidase↗
PubMedDate not supplied

IgE-mediated reactions to autoantigens in allergic diseases.

BACKGROUND: There is increasing evidence that IgE-mediated reactivity against autoantigens could play a role in the pathology of severe chronic atopic diseases. METHODS: Human mitochondrial managenese superoxide dismutase (MnSOD), acidic ribosomal P2 protein and cyclophilins were cloned by PCR, expressed as inclusion body proteins in Escherichia coli, purified by Ni2+-chelate affinity chromatography, refolded in vitro and used for further experiments. RESULTS: Human MnSOD, P2 ribosomal protein and cyclophilins respectively, show sequence identity and similarity of >50% and 70% to the corresponding allergens of Aspergillus fumigatus. The human proteins were able to bind IgE from sera of individuals sensitized to the mould proteins and to elicit strong skin reactions of the immediate type in these individuals. CONCLUSIONS: These observations provide evidence for autoreactivity to human proteins in allergic persons chronically sensitized to environmental allergens from A. fumigatus which share a high degree of sequence homology to the corresponding human proteins.

Allergens↗
PubMedDate not supplied

Tapping allergen repertoires by advanced cloning technologies.

BACKGROUND: Complex allergenic sources such as moulds, foods and mites contain complex panels of IgE-binding molecules which need to be cloned, produced and characterized in order to mimic the entire allergenicity of whole extracts reconstituted by mixing single standardized recombinant allergens. METHODS: Phage surface display of cDNA libraries selectively enriched for allergen-expressing clones using IgE from allergic patients allows rapid isolation of large panels of allergens. For the characterization of all different clones present in enriched cDNA libraries in a fast and cost-effective way, high-throughput screening technology is required. RESULTS: The combination of selective enrichment of cDNA libraries based on biopanning against serum IgE from sensitized patients and automated robot technology for picking and high-density gridding of clones onto filter membranes, followed by hybridization, enables fast identification of all the different clones present in an enriched library. The consequent application of selective enrichment and robotic-based screening allows, within weeks, cloning and characterization of the whole allergenic repertoire of any organisms. CONCLUSIONS: Robotic-based high-throughput screening of clones selected for IgE-binding capacity from phage surface-displayed cDNA libraries of Aspergillus fumigatus, Cladosporium herbarum, Coprinus comatus, Malassezia furfur, peanut and human lung tissue allowed rapid characterization of 81, 28, 37, 27, 8 and 151 different sequences, respectively. All these cDNAs bear a high probability to encode allergens derived from the respective allergenic source.

Allergens↗
PubMedDate not supplied

Cloning, production, characterization and IgE cross-reactivity of different manganese superoxide dismutases in individuals sensitized to Aspergillus fumigatus.

BACKGROUND: Manganese superoxide dismutase (MnSOD) from Aspergillus fumigatus has been demonstrated to be an allergen showing a high degree of homology with phylogenetically distant MnSODs. We describe cloning, production and characterization of MnSODs from different species. METHODS: MnSODs were cloned by PCR, expressed as inclusion body protein in Escherichia coli, purified by Ni2+-chelate affinity chromatography and characterized. RESULTS: The MnSODs from A. fumigatus, man, yeast, Drosophila melanogaster and E. coli show about 50% identity and 70% similarity on the primary structure. All proteins were produced at a high level in E. coli and refolded to achieve enzymatic activity. The proteins were able to bind IgE from sera of individuals sensitized to the A. fumigatus MnSOD. CONCLUSIONS: MnSOD represents a novel pan-allergen restricted to individuals sensitized to A. fumigatus.

Allergens↗