ABSTRACT
Interactions between primary producers and bacteria impact the physiology of both partners, alter the chemistry of their environment, and shape ecosystem diversity. In marine ecosystems, these interactions are difficult to study partly because the major photosynthetic organisms are microscopic, unicellular phytoplankton. Coastal phytoplankton communities are dominated by diatoms, which generate approximately 40% of marine primary production and form the base of many marine food webs. Diatoms co-occur with specific bacterial taxa, but the mechanisms of potential interactions are mostly unknown. Here we tease apart a bacterial consortium associated with a globally distributed diatom and find that a Sulfitobacter species promotes diatom cell division via secretion of the hormone indole-3-acetic acid, synthesized by the bacterium using both diatom-secreted and endogenous tryptophan. Indole-3-acetic acid and tryptophan serve as signalling molecules that are part of a complex exchange of nutrients, including diatom-excreted organosulfur molecules and bacterial-excreted ammonia. The potential prevalence of this mode of signalling in the oceans is corroborated by metabolite and metatranscriptome analyses that show widespread indole-3-acetic acid production by Sulfitobacter-related bacteria, particularly in coastal environments. Our study expands on the emerging recognition that marine microbial communities are part of tightly connected networks by providing evidence that these interactions are mediated through production and exchange of infochemicals.
Subject(s)
Diatoms/metabolism , Diatoms/microbiology , Ecosystem , Indoleacetic Acids/metabolism , Phytoplankton/metabolism , Phytoplankton/microbiology , Rhodobacteraceae/metabolism , Diatoms/cytology , Diatoms/genetics , Metabolomics , Molecular Sequence Data , Oceans and Seas , Photosynthesis , Phytoplankton/cytology , Phytoplankton/genetics , Rhodobacteraceae/genetics , Seawater/chemistry , Transcriptome , Tryptophan/metabolismABSTRACT
AIMS: Bacterial community structure and composition of a drinking water network were assessed to better understand this ecosystem in relation to haloacetic acid (HAA) degradation and to identify new bacterial species having HAA degradation capacities. METHODS AND RESULTS: Biofilm samples were collected from a model system, simulating the end of the drinking water distribution network and supplied with different concentrations of dichloroacetic and trichloroacetic acids at different periods over the course of a year. The samples were analysed by culturing, denaturing gradient gel electrophoresis (DGGE) and sequencing. Pipe diameter and HAA ratios did not impact the bacterial community profiles, but the season had a clear influence. Based on DGGE profiles, it appeared that a particular biomass has developed during the summer compared with the other seasons. Among the bacteria isolated in this study, those from genus Cupriavidus were able to degrade dichloroacetic acid. Moreover, these bacteria degrade dichloroacetic acid at 18°C but not at 10°C. CONCLUSIONS: The microbial diversity evolved throughout the experiment, but the bacterial community was distinct during the summer. Results obtained on the capacity of Cupriavidus to degrade DCAA only at 18°C but not at 10°C indicate that water temperature is a major element affecting DCAA degradation and confirming observations made regarding season influence on HAA degradation in the drinking water distribution network. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first demonstration of the HAA biodegradation capacity of the genus Cupriavidus.
ABSTRACT
In order to explain the cognitive and cerebral mechanisms responsible for the visuospatial peak in autism, and to document its specificity to this condition, a group of eight high-functioning individuals with autism and a visuospatial peak (HFA-P) performed a modified block-design task (BDT; subtest from Wechsler scales) at various levels of perceptual cohesiveness, as well as tasks tapping visuomotor speed, global perception, visual memory, visual search and speed of visual encoding. Their performance was compared with that of 8 autistics without a visuospatial peak (HFA-NP), 10 typically developing individuals (TD) and 8 gifted comparison participants with a visuospatial peak (TD-P). Both HFA-P and HFA-NP groups presented with diminished detrimental influence of increasing perceptual coherence compared with their BDT-matched comparison groups. Neither autistic group displayed a deficit in construction of global representations. The HFA-P group showed no differences in performance level or profile in comparison with the gifted BDT-matched [i.e. higher full-scale IQ (FSIQ)] group, apart from locally oriented perception. Diminished detrimental influence of perceptual coherence on BDT performance is both sensitive and specific to autism, and superior low-level processing interacts with locally oriented bias to produce outstanding BDT performance in a subgroup of autistic individuals. Locally oriented processing, enhanced performance in multiple tasks relying on detection of simple visual material and enhanced discrimination of first-order gratings converge towards an enhanced functioning and role of the primary visual cortex (V1) in autism. In contrast, superior or typical performance of autistics in tasks requiring global processing is inconsistent with the global-deficit-driven Weak Central Coherence hypothesis and its neurobiological magnocellular deficit counterpart.
Subject(s)
Autistic Disorder/psychology , Cognition , Visual Perception , Adolescent , Adult , Discrimination, Psychological , Humans , Intelligence , Memory , Models, Neurological , Models, Psychological , Pattern Recognition, Visual , Photic Stimulation/methods , Reaction Time , Sensitivity and Specificity , Space PerceptionABSTRACT
Configural processing in autism was studied in Experiment 1 by using the face inversion effect. A normal inversion effect was observed in the participants with autism, suggesting intact configural face processing. A priming paradigm using partial or complete faces served in Experiment 2 to assess both local and configural face processing. Overall, normal priming effects were found in participants with autism, irrespective of whether the partial face primes were intuitive face parts (i.e., eyes, nose, etc.) or arbitrary segments. An exception, however, was that participants with autism showed magnified priming with single face parts relative to typically developing control participants. The present findings argue for intact configural processing in autism along with an enhanced processing for individual face parts. The face-processing peculiarities known to characterize autism are discussed on the basis of these results and past congruent results with nonsocial stimuli.
Subject(s)
Attention , Autistic Disorder/diagnosis , Discrimination Learning , Face , Field Dependence-Independence , Pattern Recognition, Visual , Adolescent , Adult , Association Learning , Autistic Disorder/psychology , Cues , Depth Perception , Female , Humans , Intelligence , Male , OrientationABSTRACT
OBJECTIVE: To examine the reliability of the French Diagnostic Interview Schedule for Children (DISC-2.25) in Quebec in light of other DISC-2 studies conducted in the National Institute of Mental Health's Methods for the Epidemiology of Child and Adolescent Mental Disorders Study. METHOD: Reliability was assessed for DSM-III-R disorders in a community sample comprising 260 parents of youths aged 6 to 14 years and 145 adolescents aged 12 to 14 years. The DISC was completed at home. The mean test-retest interval was 13.8 days for parents and 12.8 days for adolescents. RESULTS: Parents' reports: Internal consistency was acceptable for a majority of disorders. The kappa coefficients were in the fair or good ranges except for depressive disorders and were higher for children than for adolescents, and intraclass correlations were higher than kappa coefficients. Adolescents' reports: Internal consistency was acceptable or nearly acceptable for a majority of disorders. The kappa coefficients were in the fair range, and intraclass correlations were higher than kappa coefficients. The kappa coefficients were significantly higher for the test-retest interval of 7 to 14 days than for 14 to 21 days for adolescents' reports of anxious disorders and internalizing disorders. CONCLUSION: The French DISC-2.25 shows acceptable internal consistency and fair to good test-retest reliability. Across DISC-2 studies, test-retest reliability of the parents' reports improved for anxiety and depressive disorders. Among sources of variation, studies on attributes of questions would be meaningful.
Subject(s)
Diagnosis, Computer-Assisted/standards , Interview, Psychological/standards , Mental Disorders/diagnosis , Psychometrics/standards , Adolescent , Child , Confidence Intervals , Female , Humans , Longitudinal Studies , Male , Quebec , Reproducibility of Results , TranslatingABSTRACT
Previous epidemiological studies of correlates of child and adolescent mental disorders in the general population have focused more on child/adolescent and socioeconomic/sociodemographic characteristics than on family characteristics. Moreover, there are no generally accepted methods to analyze and interpret correlates. The purpose of the Quebec Child Mental Health Survey in this regard was twofold: (1) to identify correlates of DSM-III-R internalizing and externalizing disorders according to informant (youth, parent, teacher), for three age groups (6-8, 9-11, and 12-14 years), including relevant family characteristics not considered in previous studies; and (2) to interpret the relative importance of risk indicators by ranking correlates according to strength and consistency of association across age groups. Logistic regression models suggest the inconsistency of correlates across informants. The ranking of correlates reveals that individual and family characteristics make a more important contribution than do socioeconomic characteristics, thereby supporting the relevance of proximal variables in the development of psychopathology.
Subject(s)
Mental Disorders/epidemiology , Adolescent , Adolescent Behavior/psychology , Age Factors , Child , Female , Humans , Male , Mental Disorders/diagnosis , Population Surveillance , Psychiatric Status Rating Scales , Psychology, Adolescent , Quebec/epidemiology , Reproducibility of ResultsABSTRACT
Macrocephaly has been reported as one of the few physiological markers of several syndromes which are identified during childhood. However, only a limited number of studies have investigated whether macrocephaly persists in adults in these conditions, due to an absence of up-to-date reference charts constructed for typically developing adults. Available adult head circumference reference charts either don't measure individuals beyond 21 years of age, are outdated, mostly use homogeneous samples and most importantly do not account for the individual's height and weight at the same time. Two hundred twenty-one male adults were recruited in a large urban community. For each participant, height, weight and head circumference were measured. A significant positive relationship was found between head circumference and height (r=0.379) as well as between head circumference and weight (r=0.391) and a weaker positive correlation with bodymass index (r=0.213). Charts to determine the level of head circumference abnormalities in adulthood are provided, along with a calculation formula for head circumference based on height and weight. The findings indicate the necessity of taking height and weight into account when measuring head circumference in adults.
La macrocefalia ha sido reportada como uno de los pocos marcadores fisiológicos de varios síndromes que se identifican durante la infancia. Sin embargo, sólo un número limitado de estudios han investigado si la macrocefalia persiste en los adultos con estas condiciones, debido a la ausencia de tablas de referencia actualizadas, construidas para el desarrollo normal de adultos. Las tablas de referencia de circunferencia cefálica disponible para adultos, no miden a los individuos más allá de los 21 años de edad, no están actualizadas, y la mayoría utiliza muestras homogéneas y lo más importante, no toman en cuenta al mismo tiempo la altura y peso del individuo. Fueron reclutados 221 hombres adultos de una comunidad urbana grande. En cada participante se midió la circunferencia cefálica, altura y peso. Se observó una relación significativamente positiva entre la circunferencia cefálica y la altura (r = 0,379), así como entre la circunferencia cefálica y el peso (r = 0,391), mientras la correlación positiva fue débil con el índice de masa corporal (r = 0,213). Se proporcionan tablas para determinar el nivel de anormalidades de la circunferencia cefálica en la edad adulta, junto con una fórmula de cálculo para la circunferencia cefálica basada en la altura y el peso. Los resultados indican la necesidad de tomar en cuenta altura y peso al momento de medir la circunferencia cefálica en adultos.
Subject(s)
Humans , Male , Adolescent , Adult , Middle Aged , Aged , Young Adult , Head/anatomy & histology , Reference Values , Body Height , Body Weight , Canada , Linear ModelsABSTRACT
This paper examines associations between informants, correlates and child disorders in a sample of 230 outpatients six to 14 years of age. K-SADS-E diagnoses and scores were studied according to informant, gender, age group, mental health of the parents, life events and parents' relationship. The results show that parents underreport their daughters' internalized disorders compared with reports of children and adolescents and that male children and adolescents underreport all types of disorders compared with the reports of their parents. Intra-informant correlations and differences between informants suggest an uneven influence according to informants of correlates on the report of child disorders.
Subject(s)
Affective Symptoms/diagnosis , Attention Deficit Disorder with Hyperactivity/diagnosis , Child Behavior Disorders/diagnosis , Personality Assessment/statistics & numerical data , Social Environment , Adolescent , Affective Symptoms/psychology , Age Factors , Anxiety Disorders/diagnosis , Anxiety Disorders/psychology , Attention Deficit Disorder with Hyperactivity/psychology , Child , Child Behavior Disorders/psychology , Depressive Disorder/diagnosis , Depressive Disorder/psychology , Female , Humans , Life Change Events , Male , Psychometrics , Reproducibility of Results , Sex FactorsABSTRACT
The Quebec Child Mental Health Survey (QCMHS) was conducted in 1992 on a representative sample of 2400 children and adolescents aged 6 to 14 years from throughout Quebec. Prevalences of nine Axis-I DSM-III-R (American Psychiatric Association, 1987) mental health disorders were calculated based on each informant (for 6-11-year-olds: child, parent, and teacher; for 12-14-year-olds: child and parent). Informant parallelism allows the classification of results of the demographic variables associated with disorders in the logistic regression models. This strategy applies to group variables (correlates of disorders) whereas informant agreement applies to individual diagnoses. Informant parallelism implies that results for two informants or more are in the same direction and significant. In the QCMHS, informant parallelism exists for disruptive disorders, i.e. in two ADHD regression models (child and parent) higher rates among boys and young children, and in three oppositional/conduct disorders regression models (child, parent, and teacher) higher rates among boys. No informant parallelism is observed in the logistic regression models for internalizing disorders, i.e. the patterns of association of demographic variables with anxiety and depressive disorders vary across informants. Urban-rural residence does not emerge as a significant variable in any of the logistic regression models. The overall 6-month prevalences reach 19.9% according to the parent and 15.8% according to the child. The implications of the results for policy makers and clinicians are discussed.
Subject(s)
Attitude to Health , Caregivers/psychology , Mental Disorders/epidemiology , Adolescent , Age Factors , Anxiety Disorders/diagnosis , Anxiety Disorders/epidemiology , Anxiety Disorders/psychology , Attention Deficit and Disruptive Behavior Disorders/diagnosis , Attention Deficit and Disruptive Behavior Disorders/epidemiology , Attention Deficit and Disruptive Behavior Disorders/psychology , Behavioral Symptoms/diagnosis , Behavioral Symptoms/psychology , Child , Comorbidity , Depressive Disorder/diagnosis , Depressive Disorder/epidemiology , Depressive Disorder/psychology , Female , Health Surveys , Humans , Logistic Models , Male , Manuals as Topic/standards , Mental Disorders/diagnosis , Mental Disorders/psychology , Parents , Prevalence , Quebec/epidemiology , Sampling Studies , Sex Factors , TeachingABSTRACT
INTRODUCTION: The Dominic Interactive was developed in North America to assess a child's perception of her/his own symptoms, which is critical to balance parents' and school professionals' perception. It is a computerized, DSM-IV-based pictorial questionnaire akin to a video game, for children aged 6-11. A strengths and competencies scale displays positive situations. Most children complete the Dominic Interactive 90 situations within 10-15 min. OBJECTIVE: Because of the cultural differences between North American and French children, a study of the appropriateness of the instrument to assess French children was required. METHODS: The CD-ROM-based Dominic Interactive was completed by 253 community children, and by 150 children from outpatient clinics in four French cities. The latter also received clinical diagnoses. Prevalence estimates yielded by the Dominic Interactive in the general population and referred children, relationships between prevalence estimates based on the Dominic Interactive and clinical judgments, and differences between Dominic Interactive scores in sub-samples of children with and without a clinical diagnosis were studied. RESULTS: Significant differences between clinically referred and non-referred children were found for every diagnosis, and between Dominic Interactive scores of referred children with and without a clinical diagnosis with the exception of oppositional disorder. Parental acceptability of the instrument was never a problem, children like it, and clinicians' comments were positive. DISCUSSION: Reference and clinical judgment both indicate that the Dominic Interactive is appropriate to assess child mental health in France. Clinical judgment discrepancies between sites and small numbers are the limitations of this study. CONCLUSION: The instrument performed well in the French context. The potential advantages of using the Dominic Interactive (children enjoy the activity, parents approve of it, it is relatively cost-effective, etc.) suggest its applicability in other settings.