Widespread selective sweeps throughout the genome of model plant pathogenic fungi and identification of effector candidates.

Identifying the genes underlying adaptation, their distribution in genomes and the evolutionary forces shaping genomic diversity are key challenges in evolutionary biology. Very few studies have investigated the abundance and distribution of selective sweeps in species with high-quality reference genomes, outside a handful of model species. Pathogenic fungi are tractable eukaryote models for investigating the genomics of adaptation. By sequencing 53 genomes of two species of anther-smut fungi and mapping them against a high-quality reference genome, we showed that selective sweeps were abundant and scattered throughout the genome in one species, affecting near 17% of the genome, but much less numerous and in different genomic regions in its sister species, where they left footprints in only 1% of the genome. Polymorphism was negatively correlated with linkage disequilibrium levels in the genomes, consistent with recurrent positive and/or background selection. Differential expression in planta and in vitro, and functional annotation, suggested that many of the selective sweeps were probably involved in adaptation to the host plant. Examples include glycoside hydrolases, pectin lyases and an extracellular membrane protein with CFEM domain. This study thus provides candidate genes for being involved in plant-pathogen interaction (effectors), which have remained elusive for long in this otherwise well-studied system. Their identification will foster future functional and evolutionary studies, in the plant and in the anther-smut pathogens, being model species of natural plant-pathogen associations. In addition, our results suggest that positive selection can have a pervasive impact in shaping genomic variability in pathogens and selfing species, broadening our knowledge of the occurrence and frequency of selective events in natural populations.

[Propofol infusion syndrome]. / Le syndrome de perfusion du propofol.

OBJECTIVE: Propofol is commonly used for sedation of children or adult patients in intensive care unit as an alternative to benzodiazepines for the long-term sedation of mechanically ventiled patient. However, the life-threatening complication of propofol-infusion syndrome (PRIS) may in some case occur. The objective of this article is to review the clinical features, physiopathology and management of PRIS. DATA SOURCES: A PubMed database research in English and French languages published until December 2008. Keywords were propofol, propofol infusion syndrome (PRIS), rhabdomyolysis, heart failure, arrhythmias, metabolic acidosis, brain injury, sedation, intensive care. DATA SYNTHESIS: PRIS is a rare and potentially lethal complication, especially if there's no early identification of the syndrome. The physiopathology of PRIS mechanism remains unclear, however a dysfunction of mitochondrial respiratory chain could be involved and potential genetic factor may account. Clinical features consist of arrhythmias, metabolic acidosis, lipemia, rhabdomyolisis, myoglobinuria. PRIS has been described classically in children and adults undergoing a long term infusion with propofol (more than 48 hours) at doses higher than 4 mg/kg per hour. However, it can be observed with lower doses and after shorter duration of sedation. Steroids, vasopressors and low carbohydrate intake act as triggering factors. Early recognition of the syndrome improve patient's outcome. Propofol infusion must be avoided in susceptible patients and another sedative agent should be considered. When using prolonged sedation with propofol, arrhythmia and serum triglyceridemia level should be monitored.

Education research: cognitive performance is preserved in sleep-deprived neurology residents.

OBJECTIVE: To test the hypotheses that sleep deprivation in neurology residents is associated with performance deficits and that vigilance and cognitive performance is more compromised after overnight on-call duty compared to night shift. METHODS: Thirty-eight neurology residents of a university teaching hospital participated in a prospective single-blind comparison study. Residents were recruited according to their working schedule and divided into 3 groups: 24 hours overnight on-call duty, night shift, and regular day shift (controls). All participants underwent serial measurements of sleepiness and cognitive performance in the morning directly after or before their shift. Pupillary sleepiness test and Paced Auditory Serial Addition Test were applied. Perceived sleepiness was assessed by a questionnaire. RESULTS: Sleepiness was increased in residents after night shift and overnight call compared to controls while the type of night duty was not associated with the extent of sleepiness. Sleep-deprived residents did not show any performance deficits on the Paced Auditory Serial Addition Test. Cognitive performance was not associated with sleepiness measures. CONCLUSIONS: Night shift and overnight call duty have a similar impact on alertness in neurology residents. Sleep-deprived neurology residents may be able to overcome sleep loss-related performance difficulties for short periods.

Valsalva manoeuvre in patients with different Parkinsonian disorders.

The valsalva manoeuvre (VM), used as an autonomic function test, can detect sympathetic and/or parasympathetic autonomic dysfunction. This study investigated the value of VM in patients with different Parkinsonian syndromes (PS). We continuously recorded blood pressure, ECG and respiration among 38 patients with multiple system atrophy (MSA), 32 patients with progressive supranuclear palsy (PSP), 26 patients with idiopathic Parkinson's disease (PD) and in 27 healthy subjects matched in age and sex (Con). VM was performed in addition to metronomic breathing and tilt-table testing. VM could not be analysed in 26% of the ES patients. Valsalva ratio (VR), as a parameter of cardiovagal function, was pathologically decreased in all patient groups. Valsalva ratio (VR) was not able to discriminate parasympathetic dysfunction between patients and controls as well as E/I ratio of metronomic breathing. As a parameter of sympathetic dysfunction during VM, the physiological increase of blood pressure was more often missing during phase IV than phase II especially in PD and MSA patients. Correlation with orthostatic hypotension during tilt-table testing was only moderate. Although VM can demonstrate sympathetic and parasympathetic autonomic dysfunction, we cannot recommend VM as a first line autonomic test in PS patients. Metronomic breathing and tilt-table test seem more capable as parasympathetic resp. and sympathetic function tests to identify cardiovascular abnormalities in PS patients.

Baroreflex sensitivity and power spectral analysis in different extrapyramidal syndromes.

Cardiac autonomic abnormalities have been described in Parkinson's disease and other extrapyramidal syndromes. To investigate baroreflex sensitivity as an important risk marker of cardiovascular mortality in patients with Parkinson's disease and other extrapyramidal syndromes. We recorded continuously blood pressure, ECG and respiration in 35 patients with multiple system atrophy (MSA), 32 patients with progressive supranuclear palsy (PSP), 46 patients with idiopathic Parkinson's disease (PD) and in 27 corresponding healthy subjects (Con). Recordings of 2 min at rest were used to calculate baroreflex and spectral analysis of heart rate and systolic blood pressure. Resting baroreflex sensitivity (BRS) was significantly lower in the MSA and the PSP group but not in the PD group in comparison to the Con group. With increasing Hoehn & Yahr stage, BRS significantly decreased in all patient groups. In spectral analysis, all patient groups had a significantly lower relative low frequency (LF)-band power than the healthy controls. Patients with extrapyramidal disorders frequently demonstrate pathologically decreased BRS values and abnormalities of spectral analysis. This may have fundamental impact on the cardiovascular prognosis of patients with extrapyramidal disease.

Development of an in vitro potency test for tetanus vaccines: an immunoassay based on Hc fragment determination.

In the three Rs rule context, we have developed a method to quantify tetanus toxoid by ELISA detection of the specific Hc fragment. This fragment and several anti Hc fragment antibodies have been described as protective in mice models. By developing this assay, we have detected Hc presence in tetanus toxoid. Therefore, this functional in vitro assay could replace in vivo potency assays. We have evaluated the analytical performances of this ELISA in specificity, sensitivity, precision, and linearity tests on different combined vaccine formulations. This in vitro assay has been applied to various multi-component vaccines. Results are expressed in Lf Hc/ml with reference to a purified tetanus toxoid standard expressed in Lf/ml.

Siah-1 binds and regulates the function of Numb.

The Drosophila Seven in absentia (Sina) gene product originally was described as a protein that controls cell fate decisions during eye development. Its mammalian homolog, Siah-1, recently was found to be involved in p53-dependent and -independent pathways of apoptosis and G(1) arrest. We report that Siah-1 interacts directly with and promotes the degradation of the cell fate regulator Numb. Siah-1-mediated Numb degradation leads to redistribution of endogenous cell-surface Notch to the cytoplasm and nucleus and to augmented Notch-regulated transcriptional activity. These data imply that through its ability to target Numb for degradation, Siah-1 can act as a key regulator of Numb-related activities, including Notch signaling.

Behavioral alterations associated with apoptosis and down-regulation of presenilin 1 in the brains of p53-deficient mice.

Presenilin 1 (PS1) expression is repressed by the p53 tumor suppressor. As shown herein, wild-type PS1 is an effective antiapoptotic molecule capable of significantly inhibiting p53-dependent and p53-independent cell death. We analyzed, at the functional and molecular levels, the brains of p53 knockout mice. Surprisingly, we found that lack of p53 expression induces apoptotic brain lesions, accompanied by learning deficiency and behavioral alterations. p53-deficient mice show an unexpected overexpression of p21(waf1) with subsequent down-regulation of PS1 in their brains. This process is progressive and age-dependent. These data indicate that the p53 pathway, besides affecting tumor suppression, may play a major role in regulating neurobehavioral function and cell survival in the brain.

SIAH-1 promotes apoptosis and tumor suppression through a network involving the regulation of protein folding, unfolding, and trafficking: identification of common effectors with p53 and p21(Waf1).

We have previously described biological model systems for studying tumor suppression in which, by using H-1 parvovirus as a selective agent, cells with a strongly suppressed malignant phenotype (KS or US) were derived from malignant cell lines (K562 or U937). By using cDNA display on the K562/KS cells, 15 cDNAs were now isolated, corresponding to genes differentially regulated in tumor suppression. Of these, TSAP9 corresponds to a TCP-1 chaperonin, TSAP13 to a regulatory proteasome subunit, and TSAP21 to syntaxin 11, a vesicular trafficking molecule. The 15 cDNAs were used as a molecular fingerprint in different tumor-suppression models. We found that a similar pattern of differential regulation is shared by activation of p53, p21(Waf1), and the human homologue of Drosophila seven in absentia, SIAH-1. Because SIAH-1 is differentially expressed in the various models, we characterized it at the protein and functional levels. The 32-kDa, mainly nuclear protein encoded by SIAH-1, can induce apoptosis and promote tumor suppression. These results suggest the existence of a common mechanism of tumor suppression and apoptosis shared by p53, p21(Waf1), and SIAH-1 and involving regulation of the cellular machinery responsible for protein folding, unfolding, and trafficking.

Inhibition of presenilin 1 expression is promoted by p53 and p21WAF-1 and results in apoptosis and tumor suppression.

Previously, we cloned a cDNA fragment, TSIP 2 (tumor suppressor inhibited pathway clone 2), that detects by northern blot analysis of M1-LTR6 cells a 3-kb mRNA downregulated during p53-induced apoptosis. Cloning the full-length TSIP 2 cDNA showed that it corresponds to the presenilin 1 (PS1) gene, in which mutations have been reported in early-onset familial Alzheimer's disease. Here we demonstrate that PS1 is downregulated in a series of model systems for p53-dependent and p53-independent apoptosis and tumor suppression. To investigate the biological relevance of this downregulation, we stably transfected U937 cells with antisense PS1 cDNA. The downregulation of PS1 in these U937 transfectants results in reduced growth with an increased fraction of the cells in apoptosis. When injected into mice homozygous for severe combined immunodeficiency disease (scid/scid mice), these cells show a suppression of their malignant phenotype. Our results indicate that PS1, initially identified in a neurodegenerative disease, may also be involved in the regulation of cancer-related pathways.

p21WAF-1 reorganizes the nucleus in tumor suppression.

Interphasic nuclear organization has a key function in genome biology. We demonstrate that p21WAF-1, by influencing gene expression and inducing chromosomal repositioning in tumor suppression, plays a major role as a nuclear organizer. Transfection of U937 tumor cells with p21WAF-1 resulted in expression of the HUMSIAH (human seven in absentia homologue), Rb, and Rbr-2 genes and strong suppression of the malignant phenotype. p21(WAF-1) drastically modified the compartmentalization of the nuclear genome. DNase I genome exposure and fluorescence in situ hybridization show, respectively, a displacement of the sensitive sites to the periphery of the nucleus and repositioning of chromosomes 13, 16, 17, and 21. These findings, addressing nuclear architecture modulations, provide potentially significant perspectives for the understanding of tumor suppression.

Isolation of 10 differentially expressed cDNAs in p53-induced apoptosis: activation of the vertebrate homologue of the drosophila seven in absentia gene.

We report the isolation of 10 differentially expressed cDNAs in the process of apoptosis induced by the p53 tamor suppressor. As a global analytical method, we performed a differential display of mRNA between mouse M1 myeloid leukemia cells and derived clone LTR6 cells, which contain a stably transfected temperature-sensitive mutant of p53. At 32 degrees C wild-type p53 function is activated in LTR6 cells, resulting in programmed cell death. Eight genes are activated (TSAP; tumor suppressor activated pathway), and two are inhibited (TSIP, tumor suppressor inhibited pathway) in their expression. None of the 10 sequences has hitherto been recognized as part of the p53 signaling pathway. Three TSAPs are homologous to known genes. TSAP1 corresponds to phospholipase C beta 4. TSAP2 has a conserved domain homologous to a multiple endocrine neoplasia I (ZFM1) candidate gene. TSAP3 is the mouse homologue of the Drosophila seven in absentia gene. These data provide novel molecules involved in the pathway of wild-type p53 activation. They establish a functional link between a homologue of a conserved developmental Drosophila gene and signal transduction in tumor suppression leading to programmed cell death.

Dense Alu clustering and a potential new member of the NF kappa B family within a 90 kilobase HLA class III segment.

We have conducted a detailed structural analysis of 90 kilobases (kb) of the HLA Class III region from the Bat2 gene at the centromeric end to 23 kb beyond TNF. A single contig of 80 kb was sequenced entirely with a group of four smaller contigs covering 10 kb being only partly sequenced. This region contains four known genes and a novel telomeric potential coding region. The genes are bracketed by long, dense clusters of Alu repeats belonging to all the major families. At least six new families of MER repeats and one pseudogene are intercalated within and between the Alu clusters. The most telomeric 3.8 kb contains three potential exons, one of which bears strong homology to the ankyrin domain of the DNA binding factors NF kappa B and I kappa B.