Essential and dual effects of Notch activity on a natural transdifferentiation event.

Cell identity can be reprogrammed, naturally or experimentally, albeit with low frequency. Why some cells, but not their neighbours, undergo a cell identity conversion remains unclear. We find that Notch signalling plays a key role to promote natural transdifferentiation in C.

Combinatorial Action of Temporally Segregated Transcription Factors.

Combinatorial action of transcription factors (TFs) with partially overlapping expression is a widespread strategy to generate novel gene-expression patterns and, thus, cellular diversity. Known mechanisms underlying combinatorial activity require co-expression of TFs within the same cell. Here, we describe the mechanism by which two TFs that are never co-expressed generate a new, intersectional expression pattern in C.

Direct cellular reprogramming in Caenorhabditis elegans: facts, models, and promises for regenerative medicine.

In vitro systems of cellular reprogramming [induced pluripotent stem (iPS) cells and direct reprogramming or transdifferentiation] are rapidly improving our repertoire of molecular techniques that can force cells in culture to change into a desired identity. However, the new frontier for regenerative medicine is in vivo cellular reprogramming, which in light of concerns about the safety of in vitro cell manipulations, is an increasingly attractive approach for regenerative medicine. Powerful in vivo approaches are currently being undertaken in the genetic model Caenorhabditis elegans.

Cell plasticity in Caenorhabditis elegans: from induced to natural cell reprogramming.

Achieving controlled reprogramming of differentiated cells into a desired cell type would open new opportunities in stem-cell biology and regenerative medicine. Experimentation on cell reprogramming requires a model in which cell conversion can be induced and tracked individually. The tiny nematode, Caenorhabditis elegans, owing to its known cellular lineage, allows the study of direct cell type conversion with a single-cell resolution.

Molecular typing and characterization of extended-spectrum TEM, SHV and CTX-M beta-lactamases in clinical isolates of Enterobacter cloacae.

Sixty-one non-repetitive Enterobacter cloacae ESBL producers were collected at the Amiens University Hospital in France. Eight beta-lactam resistance phenotypes (a-h) and three aminoglycoside resistance phenotypes (i-k) were identified among these isolates, and 32 different pulsotypes were observed. Of these 61 isolates, 37 were sequenced and found to harbor beta-lactamases with a pI of 5.

Molecular characterisation and mechanisms of resistance of multidrug-resistant human Salmonella enterica serovar Typhimurium isolated in Amiens (France).

Antimicrobial resistance patterns of Salmonella enterica serovar Typhimurium isolates obtained during the study period were examined. The molecular epidemiology and the mechanisms of resistance to ampicillin, chloramphenicol and tetracycline were investigated. Resistance to ampicillin increased from 59% between 1996 and 1999 to 62.