Biomedical subjects

C D'Enfert

Publications and source records attributed to C D'Enfert.

4 recordsLinked to original sources

PubMed2003

Collaborative consensus for optimized multilocus sequence typing of Candida albicans.

A panel of 86 different Candida albicans isolates was subjected to multilocus sequence typing (MLST) in two laboratories to obtain sequence data for 10 published housekeeping gene fragments. Analysis of data for all possible combinations of five, six, seven, eight, and nine of the fragments showed that a set comprising the fragments AAT1a, ACC1, ADP1, MPIb, SYA1, VPS13, and ZWF1b was the smallest that yielded 86 unique diploid sequence types for the 86 isolates. This set is recommended for future MLST with C. albicans.

Candida albicans↗

PubMed1996

Attenuated virulence of uridine-uracil auxotrophs of Aspergillus fumigatus.

Aspergillus fumigatus mutants that are deficient in the de novo UMP biosynthesis pathway because of a mutation in the pyrG gene encoding orotidine-5'-phosphate decarboxylase (and therefore auxotrophic for uridine or uracil) were evaluated in a murine model of invasive aspergillosis. These mutants were entirely nonpathogenic, and mutant conidia remained ungerminated in alveolar macrophages. Both the germination and virulence defects could be restored by supplementing the drinking water of the animals with uridine. DNA-mediated transformation of one of the pyrG mutants with the Aspergillus niger pyrG gene also restored virulence. These results suggest that uridine and uracil are limiting in the lung environment, thus preventing conidium germination and hence virulence of the pyrG mutants.

Animals↗

PubMed1989

Klebsiella pneumoniae pulS gene encodes an outer membrane lipoprotein required for pullulanase secretion.

The product of the Klebsiella pneumoniae gene pulS, which is located downstream from the pullulanase structural gene (pulA), is essential for the cell surface localization and extracellular release of pullulanase in Escherichia coli K-12. pulS is transcribed in the opposite direction to pulA, from which it is separated by a region of 624 nucleotides. Although this latter region contains a new component of the maltose regulon, pulB, which is transcribed from the pulA promoter, it is not required for pullulanase synthesis or secretion. Unlike pulA and all other pullulanase secretion genes characterized so far, the expression of pulS is not induced by growth in the presence of maltose and is unaffected by mutations in the maltose regulator gene malT. The pulS gene product was identified as a ca. 12-kilodalton outer membrane lipoprotein. The characterization of PulS brings to three the number of identified proteins which are known to be required for pullulanase secretion in addition to the components of the signal sequence-dependent general protein export pathway.

Amino Acid Sequence↗

PubMed1985

Characterization and expression of the structural gene for pullulanase, a maltose-inducible secreted protein of Klebsiella pneumoniae.

Some strains of Klebsiella pneumonia secrete pullulanase, a debranching enzyme which produces linear molecules (maltodextrins, amylose) from amylopectin and glycogen. pulA, the structural gene for pullulanase, was introduced into Escherichia coli, either on a multiple-copy-number plasmid or as a single copy in the chromosome. When in E. coli, pulA was controlled by malT, the positive regulatory gene of the maltose regulon. Indeed, pulA expression was undetectable in a malT-negative mutant and constitutive in a malTc strain. Furthermore, the plasmid carrying pulA titrated the MalT protein. When produced in E. coli, pullulanase was not localized in the same way as in K. pneumoniae. In the latter case it was first exported to the outer membrane, with which it remained loosely associated, and was then released into the growth medium. In E. coli the enzyme was distributed both in the inner and the outer membranes and was never released into the growth medium.

Cell Membrane↗