Biomedical subjects

N Joly

Publications and source records attributed to N Joly.

7 recordsLinked to original sources

PubMed2006

A second paradigm for gene activation in bacteria.

Control of gene expression is key to development and adaptation. Using purified transcription components from bacteria, we employ structural and functional studies in an integrative manner to elaborate a detailed description of an obligatory step, the accessing of the DNA template, in gene expression. Our work focuses on a specialized molecular machinery that utilizes ATP hydrolysis to initiate DNA opening and permits a description of how the events triggered by ATP hydrolysis within a transcriptional activator can lead to DNA opening and transcription. The bacterial EBPs (enhancer binding proteins) that belong to the AAA(+) (ATPases associated with various cellular activities) protein family remodel the RNAP (RNA polymerase) holoenzyme containing the sigma(54) factor and convert the initial, transcriptionally silent promoter complex into a transcriptionally proficient open complex using transactions that reflect the use of ATP hydrolysis to establish different functional states of the EBP. A molecular switch within the model EBP we study [called PspF (phage shock protein F)] is evident, and functions to control the exposure of a solvent-accessible flexible loop that engages directly with the initial RNAP promoter complex. The sigma(54) factor then controls the conformational changes in the RNAP required to form the open promoter complex.

Bacteria↗

PubMed2005

Interaction of an optical soliton with a dispersive wave.

Scattering of a dispersive wave by optical solitons is studied experimentally in photonic crystal fibers in cases when the soliton and the dispersive wave have either identical or orthogonal polarization states. Observations of new resonant frequencies are reported. The experimental results are compared to numerical simulations and predictions from the recently derived wave vector matching conditions.

Journal Article↗

PubMed2004

Reactive airways dysfunction syndrome caused by bromochlorodifluoromethane from fire extinguishers.

Although the neurological and cardiovascular effects of Freons have been extensively described, the respiratory effects have been less well documented. We report four cases of occupational asthma following accidental exposure to bromochlorodifluoromethane (Halon 1211) due to release of the contents of a fire extinguisher. All subjects developed an irritative reaction of the upper airways and lower respiratory symptoms immediately after exposure. Non-specific bronchial hyperreactivity was present for at least two months in all subjects and was still present more than two years after exposure in one case. The diagnosis of reactive airways dysfunction syndrome can be adopted in at least three of these four cases.

Adult↗

PubMed2004

Sequence protein alignment with composition new evolutions (SPACne): a program for the identification of polypeptides using amino acid composition. A user friendly modification of SPAC.

SPAC (sequence protein alignment with composition) is a software that retrieve from protein or nucleic acid databases, the sequences corresponding to a protein or peptide whose only amino acid composition and molecular weight are known. By accurately matching a DNA or a protein sequence to candidate protein or peptide fragment, this software may be used as a fast and cheap method for protein characterization. This paper describes a modification of the SPAC software, SPAC new evolutions (SPACne), which enables a more efficient and user friendly method of protein identification using amino acids composition. SPACne is available online at the web site: http://bioweb.pasteur.fr/seqanal/interfaces/spacne.html.

Algorithms↗

PubMed2003

[Outcome at 2 years of very premature infants cared at the hospital of Cayenne in 1998].

UNLABELLED: Perinatal mortality in French Guyana is twice as high as the national rates. Within a global project rallying all the people working around the birth, a catching up program benefited the neonatal unit of the Cayenne hospital in order to make up for the important lack of modern structures and means. OBJECTIVES: To establish some quality care for the less than 33 weeks preterm infants born in 1998, and to estimate the medical and familial future for these infants after they have reached 2 years of age. METHODS: All less than 33 weeks old infants born alive and admitted at the neonatology unit of the CHC were included in the study. The obstetrical and neonatal data were recorded from the medical files. A survey was conducted through a questionnaire including the familial and medical outcome and was led from december 1999 to july 2001. Results were analysed with Epi-info 6.0 software (CDC, Atlanta, USA). RESULTS: Eighty-eight infants issue from 78 pregnancies were included. Among them, 29 were transferred in utero and 12 were transferred after birth. The mothers' situations were mainly characterized by precariousness, a poor follow-up of the pregnancy (27% non-declared), a higher morbidity of their newborns. Neonatal results did not differ from national results from Epipage cohort in terms of gestational age (29.9 weeks), weight at birth (1411 g), mortality (90.9 alive when released from the hospital), morbidity, growth at 2. However, 26% were hypotrophic (15% in Epipage cohort) in relation with the 29% pregnancies complicated with hypertension. Four infants were suffering from acquisition retardation due to motor handicaps; 2 infants had severe socio-educative difficulties. The postnatal follow-up was mainly performed by the Mother and Children Health Centers. A third of medical exams were not recorded in the health book, sensory screening exams were not performed. The opening of a medicosocial actions center in 2001, will allow a prospective follow-up of this population. CONCLUSION: Early neonatal mortality decreased from 10.3 for 1000 births to 4.4 in 1998. This reflects the improvement of the new-born caring possibilities. However, an improvement of mortality rates will not be possible without a better pregnancy follow-up.

Female↗

PubMed2000

Genome-wide protein interaction screens reveal functional networks involving Sm-like proteins.

A set of seven structurally related Sm proteins forms the core of the snRNP particles containing the spliceosomal U1, U2, U4 and U5 snRNAs. A search of the genomic sequence of Saccharomyces cerevisiae has identified a number of open reading frames that potentially encode structurally similar proteins termed Lsm (Like Sm) proteins. With the aim of analysing all possible interactions between the Lsm proteins and any protein encoded in the yeast genome, we performed exhaustive and iterative genomic two-hybrid screens, starting with the Lsm proteins as baits. Indeed, extensive interactions amongst eight Lsm proteins were found that suggest the existence of a Lsm complex or complexes. These Lsm interactions apparently involve the conserved Sm domain that also mediates interactions between the Sm proteins. The screens also reveal functionally significant interactions with splicing factors, in particular with Prp4 and Prp24, compatible with genetic studies and with the reported association of Lsm proteins with spliceosomal U6 and U4/U6 particles. In addition, interactions with proteins involved in mRNA turnover, such as Mrt1, Dcp1, Dcp2 and Xrn1, point to roles for Lsm complexes in distinct RNA metabolic processes, that are confirmed in independent functional studies. These results provide compelling evidence that two-hybrid screens yield functionally meaningful information about protein-protein interactions and can suggest functions for uncharacterized proteins, especially when they are performed on a genome-wide scale.

Fungal Proteins↗

PubMed1999

Slow heat rate increases yeast thermotolerance by maintaining plasma membrane integrity.

Thermal resistance of Saccharomyces cerevisiae was found to be drastically dependent on the kinetics of heat perturbation. Yeasts were found to be more resistant to a plateau of 1 h at 50 degrees C after a slope of temperature increase (slow and linear temperature increments) than after a shock (sudden temperature change). Thermotolerance was mainly acquired between 40-50 degrees C during a heat slope, i.e., above the maximal temperature of growth. The death of the yeasts subjected to a heat shock might be related to the loss of membrane integrity: intracellular contents extrusion, i.e., membrane permeabilization, was found to precede cell death. However, the permeabilization did not precede cell death during a heat slope and, therefore, membrane permeabilization was a consequence rather than a cause of cell death. During a slow temperature increase, yeasts which remain viable may have time to adapt their plasma membrane and thus maintain membrane integrity.

Cations↗