Complex regulatory network controls initial adhesion and biofilm formation in Escherichia coli via regulation of the csgD gene.

The Escherichia coli OmpR/EnvZ two-component regulatory system, which senses environmental osmolarity, also regulates biofilm formation. Up mutations in the ompR gene, such as the ompR234 mutation, stimulate laboratory strains of E. coli to grow as a biofilm community rather than in a planktonic state. In this report, we show that the OmpR234 protein promotes biofilm formation by binding the csgD promoter region and stimulating its transcription. The csgD gene encodes the transcription regulator CsgD, which in turn activates transcription of the csgBA operon encoding curli, extracellular structures involved in bacterial adhesion. Consistent with the role of the ompR gene as part of an osmolarity-sensing regulatory system, we also show that the formation of biofilm by E. coli is inhibited by increasing osmolarity in the growth medium. The ompR234 mutation counteracts adhesion inhibition by high medium osmolarity; we provide evidence that the ompR234 mutation promotes biofilm formation by strongly increasing the initial adhesion of bacteria to an abiotic surface. This increase in initial adhesion is stationary phase dependent, but it is negatively regulated by the stationary-phase-specific sigma factor RpoS. We propose that this negative regulation takes place via rpoS-dependent transcription of the transcription regulator cpxR; cpxR-mediated repression of csgB and csgD promoters is also triggered by osmolarity and by curli overproduction, in a feedback regulation loop.

[Adaptation of adolescents to the death or divorce of parents.]. / Adaptation des adolescents au décès ou au divorce des parents.

Research conducted on a sample of 5,539 francophone adolescents of the island of Montréal (from first year of High School to last year of Cégep) shows 446 children with divorced parents (9.82 %) and 330 orphans (7.27%). Simple and controlled comparisons of these two groups with adolescents living with both parents reveal a regular pattern where children of divorced families perceive themselves at a disadvantage, followed by orphans in the middle. The authors also analyse how the length of a divorce, the age at which parents divorced and the sex of the guardian parent influence the children. The authors then discuss the fact there are more girls born from divorced families.

Adolescents' perception of self and of immediate environment by parental marital status: a controlled study.

Most studies on children of "broken families" are based on small and unrepresentative samples, are limited to children of divorce and do not control for basic demographic variables. In order to do a survey with fewer methodological deficiencies, we managed to obtain a completely representative sample of a Francophone urban population attending High School I, II and III, with the reasonable sample size of 1519 subjects and including 72 subjects from widowed families in addition to 174 children of divorce; furthermore, we were able to control for the following eight demographic variables: father's and mother's occupation, mother's work, respondent's, father's and mother's age, family size, and respondent's rank of birth. When comparing children from legally intact, widowed, and divorced families, on a wide range of psychosocial variables, we found that on the average, divorce is associated with the greatest disadvantage in children, followed by widowhood; children belonging to intact families show the least disadvantage. Besides, when comparing girls and boys, we did not find striking differences between them in divorced families, but, on the other hand, we found striking differences in widowed families, boys being at much more disadvantage than girls. It is concluded that on the average a family breakup should be considered as a serious risk factor for teenagers and that clinicians would be well advised to monitor the situation carefully when aware of an impending family breakup.

Parental marital status and adolescents' health-risk behavior.

This article reports the results of a questionnaire survey of a representative random sample of all the in-school Francophone adolescents of Montreal. The sample size was 4,539 and included adolescents from legally intact homes, separated/divorced homes, and homes in which a parent was decreased. Health-risk behavioral indicators were smoking (how many cigarettes a day), fastening of car seat belts, and intemperate drinking. Adolescents who lived in intact families engaged less in health-risk behavior than the other adolescents, especially those from separated/divorced families. The results for adolescents from widowed families were mixed. Several mutually complementary explanations are presented.

Drug use in separated/divorced persons. Gender, parental status, and socio-economic status.

The purpose of this research was to explore drug use in a group of 49 separated/divorced persons. We differentiated between nonprescribed, prescribed psychotropic drugs, and other prescribed drugs. The research technique consisted of 3-h in-depth interviews. The independent variables were gender, socio-economic status, and the subjects' own parental status. Contrary to earlier studies, we found a higher drug use among men than women. Combinations of gender with socio-economic status followed different drug use patterns. Higher-status custodial mothers and custodial fathers had the lowest drug use. These results are explored within the framework of gender role atypicality, and suggest that intra-sex variations may be more meaningful to research than broad comparisons between men and women.

Parental marital status and adolescents' optimism about their future.

This article reports the results of a questionnaire survey of a representative random sample of all the schooled French-speaking adolescents of Montreal (N=4539). The sample included adolescents from legally intact homes, separated or divorced homes, and homes in which a parent was deceased. Three indicators of future success were included; adolescents from both types of broken families were less optimistic on all three dimensions than were adolescents from intact families. These results are discussed within a socioeconomic framework.