Biomedical subjects

Isabelle Lanneluc

Publications and source records attributed to Isabelle Lanneluc.

3 recordsLinked to original sources

PubMed2004

Characterization of a centromeric marker on mouse chromosome 11 and its introgression in a domesticus/musculus hybrid zone.

It has been proposed that the distribution of Robertsonian chromosome fusions and the Chromosome 11 Nucleolar Organizer Region (NOR) in the Danish hybrid zone between M. m. musculus and M. m. domesticus stems from centromeric incompatibilities between the two subspecies. To test this hypothesis, we identified and characterized a diagnostic subspecific marker closely linked to the centromere on mouse Chromosome 11. Using an allele-specific PCR assay, we investigated the introgression pattern of this centromere in a large sample of mice from a North-South transect of the hybrid zone in Jutland. Domesticus alleles were found to introgress far away from the center of the zone on the musculus side. These results suggest there is no incompatibility between the domesticus centromere of Chromosome 11 in the musculus genomic background.

Animals↗

PubMed2004

Genetic analysis and complete primary structure of microcin L.

Escherichia coli LR05, in addition to producing MccB17, J25, and D93, secretes microcin L, a newly discovered microcin that exhibits strong antibacterial activity against related Enterobacteriaceae, including Salmonella enterica serovars Typhimurium and Enteritidis. Microcin L was purified using a two-step procedure including solid-phase extraction and reverse-phase C(18) high-performance liquid chromatography. A 4,901-bp region of the DNA plasmid of E. coli LR05 was sequenced revealing that the microcin L cluster consists of four genes, mclC, mclI, mclA, and mclB. The structural gene mclC encoded a 105-amino-acid precursor with a 15-amino-acid N-terminal extension ending with a Gly-Ala motif upstream of the cleavage site. This motif is typical of the class II microcins and other gram-positive bacteriocins exported by ABC transporters. The mclI immunity gene was identified upstream of the mclC gene and encodes a 51-amino-acid protein with two potential transmembrane domains. Located on the reverse strand, two genes, mclA and mclB, encoded the proteins MclA and MclB, respectively. They bear strong relatedness with the ABC transporter proteins and accessory factors involved in the secretion of microcins H47, V, E492, and 24. The microcin L genetic system resembles the genetic organization of MccV. Furthermore the MccL primary structure has been determined. It is a 90-amino-acid peptide of 8,884 Da with two disulfide bridges. The N-terminal region has significant homologies with several gram-positive bacteriocins. The C-terminal 32-amino-acid sequence is 87.5% identical to that of MccV. Together, these results strongly indicate that microcin L is a gram-negative class II microcin.

ATP-Binding Cassette Transporters↗

PubMedDate not supplied

New developments in non-post translationally modified microcins.

Microcins are a family of low molecular weight antibiotic peptides produced by Enterobacteriaceae strains and active against related bacteria. According to some features we propose to classify these antibiotic substances into two distinct groups. The class I microcins contain Mcc B17, C7, J25 and D93 that are small molecules (molecular mass inferior to 5 kDa), largely post-translationally modified and with specific intracellular targets. The class II microcins, MccV, E492, H47, L and 24, share several common properties with class IIa Gram-positive bacteriocins: molecular mass ranging from 7 to 10 kDa, absence of modified amino acids, double-glycine type leader peptides, secretion mediated by an ABC transporter and antibacterial activity due to interaction with bacterial membrane. This review discusses common features of the class II microcins and provides new insights into these peptides.

Amino Acid Sequence↗