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1.
Int J Parasitol ; 29(9): 1437-46, 1999 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10579430

RESUMEN

The gene encoding the cytoplasmic copper/zinc superoxide dismutase (AVSOD1) from the filarial parasite Acanthocheilonema viteae was isolated from a genomic DNA library using a degenerate oligonucleotide probe. Additionally, cDNAs of the AVSOD1 and the secreted extracellular SOD (AVSOD2) were both cloned by RT-PCR, and the AVSOD2 was expressed at high levels in E. coli. The amino acid sequence of the AVSOD1 is 89.5 and 87.5% identical to that of the corresponding enzymes of Brugia pahangi and Onchocerca volvulus, respectively. In contrast, the AVSOD2 shows a lower degree of identity to the other filarial SODs and is extensively glycosylated. RT-PCR studies demonstrate the expression of both SOD subtypes in all developmental stages of A. viteae and indicate up-regulation of the AVSOD2 expression after transmission from the vector to the definitive host. This suggests an enhanced requirement for SOD activity in post-infective larval stages and adults of A. viteae. ELISAs performed with purified recombinant AVSOD2 show that the AVSOD2 is not a major target for the immune system in naturally infected jirds.


Asunto(s)
Infecciones por Dipetalonema/veterinaria , Regulación Enzimológica de la Expresión Génica , Gerbillinae/parasitología , Enfermedades de los Roedores/enzimología , Superóxido Dismutasa/genética , Secuencia de Aminoácidos , Animales , Infecciones por Dipetalonema/enzimología , Infecciones por Dipetalonema/transmisión , Datos de Secuencia Molecular , ARN de Helminto/análisis , ARN Mensajero/análisis , Especies Reactivas de Oxígeno/metabolismo , Homología de Secuencia de Aminoácido , Regulación hacia Arriba
2.
J Biol Chem ; 274(35): 24585-92, 1999 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-10455123

RESUMEN

Signal peptides direct the export of secretory proteins from the cytoplasm. After processing by signal peptidase, they are degraded in the membrane and cytoplasm. The resulting fragments can have signaling functions. These observations suggest important roles for signal peptide peptidases. The present studies show that the Gram-positive eubacterium Bacillus subtilis contains two genes for proteins, denoted SppA and TepA, with similarity to the signal peptide peptidase A of Escherichia coli. Notably, TepA also shows similarity to ClpP proteases. SppA of B. subtilis was only required for efficient processing of pre-proteins under conditions of hyper-secretion. In contrast, TepA depletion had a strong effect on pre-protein translocation across the membrane and subsequent processing, not only under conditions of hyper-secretion. Unlike SppA, which is a typical membrane protein, TepA appears to have a cytosolic localization, which is consistent with the observation that TepA is involved in early stages of the secretion process. Our observations demonstrate that SppA and TepA have a role in protein secretion in B. subtilis. Based on their similarity to known proteases, it seems likely that SppA and TepA are specifically required for the degradation of proteins or (signal) peptides that are inhibitory to protein translocation.


Asunto(s)
Adenosina Trifosfatasas/genética , Bacillus subtilis/enzimología , Proteínas Bacterianas , Endopeptidasas/genética , Péptido Hidrolasas/genética , Señales de Clasificación de Proteína/metabolismo , Serina Endopeptidasas/genética , Adenosina Trifosfatasas/metabolismo , Secuencia de Aminoácidos , Bacillus subtilis/genética , Proteínas de la Membrana Bacteriana Externa/metabolismo , Secuencia Conservada , Citosol/enzimología , Endopeptidasa Clp , Endopeptidasas/metabolismo , Regulación Bacteriana de la Expresión Génica , Datos de Secuencia Molecular , Mutación , Péptido Hidrolasas/metabolismo , Precursores de Proteínas/metabolismo , Procesamiento Proteico-Postraduccional , Homología de Secuencia de Aminoácido , Serina Endopeptidasas/metabolismo , Transformación Genética , alfa-Amilasas/metabolismo
3.
Parasite Immunol ; 21(4): 219-24, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10320619

RESUMEN

The recombinant extracellular copper/zinc superoxide dismutase of the filarial parasite Acanthocheilonema viteae (AVSOD2) was cloned in an expression vector under control of the bacteriophage T7 promoter and the resulting plasmid pLAT7 was introduced in tha aroA attenuated Salmonella typhimurium vaccine strain SL3261:pYZ84. This vaccine strain carries a chromosomally integrated two phase expression system containing inducible T7 RNA polymerase. The recombinant AVSOD2 was efficiently expressed, constituting up to 5% of the total bacterial protein. Furthermore, the plasmid vector containing the AVSOD2 cDNA was shown to be stable over a long period of time in the vaccine strain without antibiotic selection in vitro and in vivo. Jirds which were immunised orally with the recombinant vaccine strain expressing the A. viteae EC-SOD produced a strong humoral immune response.


Asunto(s)
Antígenos Helmínticos/inmunología , Dipetalonema/inmunología , Superóxido Dismutasa/inmunología , Administración Oral , Animales , Anticuerpos Antihelmínticos/sangre , Vacunas Bacterianas/inmunología , Dipetalonema/enzimología , Portadores de Fármacos , Gerbillinae , Proteínas Recombinantes/inmunología , Salmonella typhimurium/inmunología , Superóxido Dismutasa/genética
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