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Altered heart rate (HR) and heart rate variability (HRV) are common observations in psychiatric disorders. Yet, few studies have examined these cardiac measures in obsessive-compulsive disorder (OCD). The current study aimed to investigate HR and HRV, indexed by the root mean square of successive differences (RMSSD) and further time domain indices, as putative biological characteristics of OCD. Electrocardiogram was recorded during a five-minute resting state. Group differences between patients with OCD (n = 96), healthy participants (n = 112), and unaffected first-degree relatives of patients with OCD (n = 47) were analyzed. As potential moderators of group differences, we examined the influence of age and medication, respectively. As results indicated, patients with OCD showed higher HR and lower HRV compared to healthy participants. These group differences were not moderated by age. Importantly, subgroup analyses showed that only medicated patients displayed lower HRV compared to healthy individuals, while HR alterations were evident in unmedicated patients. Regarding unaffected first-degree relatives, group differences in HRV remained at trend level. Further, an age-moderated group differentiation showed that higher HRV distinguished relatives from healthy individuals in young adulthood, whereas at higher age lower HRV was indicative of relatives. Both the role of familial risk and medication in HRV alterations need further elucidation. Pending future studies, alterations in HR and potentially HRV might serve as useful indices to characterize the pathophysiology of OCD., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Obsessive-compulsive disorder (OCD) is a prevalent mental disorder affecting ~2-3% of the population. This disorder involves genetic and, possibly, epigenetic risk factors. The dynamic nature of epigenetics also presents a promising avenue for identifying biomarkers associated with symptom severity, clinical progression, and treatment response in OCD. We, therefore, conducted a comprehensive case-control investigation using Illumina MethylationEPIC BeadChip, encompassing 185 OCD patients and 199 controls recruited from two distinct sites in Germany. Rigorous clinical assessments were performed by trained raters employing the Structured Clinical Interview for DSM-IV (SCID-I). We performed a robust two-step epigenome-wide association study that led to the identification of 305 differentially methylated CpG positions. Next, we validated these findings by pinpointing the optimal set of CpGs that could effectively classify individuals into their respective groups. This approach identified a subset comprising 12 CpGs that overlapped with the 305 CpGs identified in our EWAS. These 12 CpGs are close to or in genes associated with the sweet-compulsive brain hypothesis which proposes that aberrant dopaminergic transmission in the striatum may impair insulin signaling sensitivity among OCD patients. We replicated three of the 12 CpGs signals from a recent independent study conducted on the Han Chinese population, underscoring also the cross-cultural relevance of our findings. In conclusion, our study further supports the involvement of epigenetic mechanisms in the pathogenesis of OCD. By elucidating the underlying molecular alterations associated with OCD, our study contributes to advancing our understanding of this complex disorder and may ultimately improve clinical outcomes for affected individuals., (© 2023. The Author(s).)

Background: Virtual reality (VR) technologies are playing an increasingly important role in the diagnostics and treatment of mental disorders., Objective: To systematically review the current evidence regarding the use of VR in the diagnostics and treatment of mental disorders., Data Source: Systematic literature searches via PubMed (last literature update: 9 th of May 2022) were conducted for the following areas of psychopathology: Specific phobias, panic disorder and agoraphobia, social anxiety disorder, generalized anxiety disorder, posttraumatic stress disorder (PTSD), obsessive-compulsive disorder, eating disorders, dementia disorders, attention-deficit/hyperactivity disorder, depression, autism spectrum disorder, schizophrenia spectrum disorders, and addiction disorders., Eligibility Criteria: To be eligible, studies had to be published in English, to be peer-reviewed, to report original research data, to be VR-related, and to deal with one of the above-mentioned areas of psychopathology., Study Evaluation: For each study included, various study characteristics (including interventions and conditions, comparators, major outcomes and study designs) were retrieved and a risk of bias score was calculated based on predefined study quality criteria., Results: Across all areas of psychopathology, k = 9315 studies were inspected, of which k = 721 studies met the eligibility criteria. From these studies, 43.97% were considered assessment-related, 55.48% therapy-related, and 0.55% were mixed. The highest research activity was found for VR exposure therapy in anxiety disorders, PTSD and addiction disorders, where the most convincing evidence was found, as well as for cognitive trainings in dementia and social skill trainings in autism spectrum disorder., Conclusion: While VR exposure therapy will likely find its way successively into regular patient care, there are also many other promising approaches, but most are not yet mature enough for clinical application., Review Registration: PROSPERO register CRD42020188436., Funding: The review was funded by budgets from the University of Bonn. No third party funding was involved., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interests., (Copyright © 2022. Published by Elsevier Ltd.)

Understanding the genomic basis of memory processes may help in combating neurodegenerative disorders. Hence, we examined the associations of common genetic variants with verbal short-term memory and verbal learning in adults without dementia or stroke (N = 53,637). We identified novel loci in the intronic region of CDH18, and at 13q21 and 3p21.1, as well as an expected signal in the APOE/APOC1/TOMM40 region. These results replicated in an independent sample. Functional and bioinformatic analyses supported many of these loci and further implicated POC1. We showed that polygenic score for verbal learning associated with brain activation in right parieto-occipital region during working memory task. Finally, we showed genetic correlations of these memory traits with several neurocognitive and health outcomes. Our findings suggest a role of several genomic loci in verbal memory processes., (© 2022. The Author(s).)

Schizotypy refers to a set of personality traits that bear resemblance, at subclinical level, to psychosis. Despite evidence of similarity at multiple levels of analysis, direct comparisons of schizotypy and clinical psychotic disorders are rare. Therefore, we used functional magnetic resonance imaging (fMRI) to examine the neural correlates and task-based functional connectivity (psychophysiological interactions; PPI) of smooth pursuit eye movements (SPEM) in patients with recent onset psychosis (ROP; n = 34), participants with high levels of negative (HNS; n = 46) or positive (HPS; n = 41) schizotypal traits, and low-schizotypy control participants (LS; n = 61) using machine-learning. Despite strong previous evidence that SPEM is a highly reliable marker of psychosis, patients and controls could not be significantly distinguished based on SPEM performance or blood oxygen level dependent (BOLD) signal during SPEM. Classification was, however, significant for the right frontal eye field (FEF) seed region in the PPI analyses but not for seed regions in other key areas of the SPEM network. Applying the right FEF classifier to the schizotypal samples yielded decision scores between the LS and ROP groups, suggesting similarities and dissimilarities of the HNS and HPS samples with the LS and ROP groups. The very small difference between groups is inconsistent with previous studies that showed significant differences between patients with ROP and controls in both SPEM performance and underlying neural mechanisms with large effect sizes. As the current study had sufficient power to detect such differences, other reasons are discussed., (© The Author(s) 2022. Published by Oxford University Press on behalf of the University of Maryland's school of medicine, Maryland Psychiatric Research Center.)

Obsessive-compulsive disorder (OCD) has recently been linked to increased methylation levels in the oxytocin receptor ( OXTR ) gene, and OXTR hypermethylation has predicted a worse treatment response to cognitive-behavioural therapy (CBT). Furthermore, OCD is associated with childhood trauma and stressful life events, which have both been shown to affect OXTR methylation. Here, we aimed to replicate findings of increased OXTR methylation as a predictor of disease and worse treatment response in an independent sample that received treatment within the public health care system. In addition, we aimed to extend previous findings by examining associations between OXTR hypermethylation, environmental stressors, OCD diagnosis, and treatment response. Methylation levels at two CpGs within OXTR exon III were compared between n = 181 OCD patients and n = 199 healthy controls using linear regression analysis. In a subsample of OCD patients ( n = 98) with documented treatment data, we examined associations between methylation and treatment response to CBT. Childhood adversity and stressful life events were assessed using Childhood Trauma Questionnaire and Life Experience Survey, respectively. OCD patients exhibited significant hypermethylation at CpG site cg04523291 compared to controls, and increased methylation was associated with impaired treatment response. Moreover, hypermethylation at cg04523291 was associated with stressful life events in OCD patients, and with childhood adversity in controls. Yet, there were no significant mediation effects. In conclusion, we replicated the association between OXTR hypermethylation and OCD in the largest sample, so far. Furthermore, our findings support the role of OXTR methylation as a promising biomarker for treatment response in OCD.

Background: Although cognitive behavioral therapy is a highly effective treatment for obsessive-compulsive disorder (OCD), yielding large symptom reductions on the group level, individual treatment response varies considerably. Identification of treatment response predictors may provide important information for maximizing individual treatment response and thus achieving efficient treatment resource allocation. Here, we investigated the predictive value of previously identified biomarkers of OCD, namely the error-related activity of the supplementary motor area (SMA) and the sensorimotor network (SMN, postcentral gyrus/precuneus)., Methods: Seventy-two participants with a primary diagnosis of OCD underwent functional magnetic resonance imaging (fMRI) scanning while performing a flanker task prior to receiving routine-care CBT., Results: Error-related BOLD response of the SMN significantly contributed to the prediction of treatment response beyond the variance accounted for by clinical and sociodemographic variables. Stronger error-related SMN activity at baseline was associated with a higher likelihood of treatment response., Conclusions: The present results illustrate that the inclusion of error-related SMN activity can significantly increase treatment response prediction quality in OCD. Stronger error-related activity of the SMN may reflect the ability to activate symptom-relevant processing networks and may thus facilitate response to exposure-based CBT interventions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Inhibitory control is a crucial executive function with high relevance to mental and physical well-being. However, there are still unanswered questions regarding its neural mechanisms, including the role of the major inhibitory neurotransmitter, γ-aminobutyric acid (GABA)., Aims: This study examined the effects of lorazepam (0.5 mg and 1 mg), a positive allosteric modulator at the GABA A receptor, on response inhibition and interference control. We also explored the heterogeneity of inhibitory control and calculated delta plots to explore whether lorazepam affects the gradual build-up of inhibition and activation over time., Methods: N  = 50 healthy participants performed antisaccade, Eriksen flanker and Simon tasks in a within-subjects, placebo-controlled, double-blind randomized design., Results: Lorazepam increased reaction time (RT) and error rates dose dependently in all tasks ( p  ⩽ 0.005). In the antisaccade and Simon tasks, lorazepam increased congruency effects for error rate ( p  ⩽ 0.029) but not RT ( p  ⩾ 0.587). In the Eriksen flanker task, both congruency effects were increased by the drug ( p  ⩽ 0.031). Delta plots did not reflect drug-induced changes in inhibition and activation over time. Delta plots for RT in the Simon task were negative-going, as expected, whereas those for the antisaccade and flanker tasks were positive-going., Conclusions: This study provides evidence for GABAergic involvement in performance on response inhibition and interference control tasks. Furthermore, our findings highlight the diversity of the broader construct of inhibitory control while also pointing out similarities between different inhibitory control tasks. In contrast to RT and error rates, the cognitive processes indexed by delta plots may not be sensitive to GABAergic modulation.

Background: Obsessive-compulsive disorder (OCD) is a psychiatric disorder with multiple symptom dimensions (e.g. contamination, symmetry). OCD clusters in families and decades of twin studies clearly demonstrate an important role for genetics in the etiology of the disorder., Methods: In this review, we summarize the genetic epidemiology and molecular genetic studies of OCD and obsessive-compulsive symptoms., Results: OCD is a heritable, polygenic disorder with contributions from both common and rare variants, including de novo deleterious variations. Multiple studies have provided reliable support for a large additive genetic contribution to liability to OCD, with discrete OCD symptom dimensions having both shared and unique genetic risks. Genome-wide association studies have not produced significant results yet, likely because of small sample sizes, but larger meta-analyses are forthcoming. Both twin and genome-wide studies show that OCD shares genetic risk with its comorbid conditions (e.g. Tourette syndrome and anorexia nervosa)., Conclusions: Despite significant efforts to uncover the genetic basis of OCD, the mechanistic understanding of how genetic and environmental risk factors interact and converge at the molecular level to result in OCD's heterogeneous phenotype is still mostly unknown. Future investigations should increase ancestral genetic diversity, explore age and/or sex differences in genetic risk for OCD and expand the study of pharmacogenetics, gene expression, gene × environment interactions and epigenetic mechanisms for OCD.

Alterations in frontal and parietal neural activations during working memory task performance have been suggested as a candidate endophenotype of obsessive-compulsive disorder (OCD) in studies involving first-degree relatives. However, the direct link between genetic risk for OCD and neuro-functional alterations during working memory performance has not been investigated to date. Thus, the aim of the current functional magnetic resonance imaging (fMRI) study was to test the direct association between polygenic risk for OCD and neural activity during the performance of a numeric n-back task with four working memory load conditions in 128 participants, including patients with OCD, unaffected first-degree relatives of OCD patients, and healthy controls. Behavioral results show a significant performance deficit at high working memory load in both patients with OCD and first-degree relatives (p < 0.05). A whole-brain analysis of the fMRI data indicated decreased neural activity in bilateral inferior parietal lobule and dorsolateral prefrontal cortex in both patients and relatives. Most importantly, OCD polygenic risk scores predicted neural activity in orbitofrontal cortex. Results indicate that genetic risk for OCD can partly explain alterations in brain response during working memory performance, supporting the notion of a neuro-functional endophenotype for OCD., (© 2021. The Author(s).)

Background: Indicators of increased error monitoring are associated with obsessive-compulsive disorder (OCD), as shown in electroencephalography and functional magnetic resonance imaging studies. As most studies used strictly controlled samples (excluding comorbidity and medication), it remains open whether these findings extend to naturalistic settings. Thus, we assessed error-related brain activity in a large, naturalistic OCD sample. We also explored which activity patterns might qualify as vulnerability endophenotypes or protective factors for the disorder. To this aim, a sample of unaffected first-degree relatives of patients with OCD was also included., Methods: Participants (84 patients with OCD, 99 healthy control participants, and 37 unaffected first-degree relatives of patients with OCD) completed a flanker task while blood oxygen level-dependent responses were measured with functional magnetic resonance imaging. Aberrant error-related brain activity in patients and relatives was identified., Results: Patients with OCD showed increased error-related activity in the supplementary motor area and within the default mode network, specifically in the precuneus and postcentral gyrus. Unaffected first-degree relatives showed increased error-related activity in the bilateral inferior frontal gyrus., Conclusions: Increased supplementary motor area and default mode network activity in patients with OCD replicates previous studies and might indicate excessive error signals and increased self-referential error processing. Increased activity of the inferior frontal gyrus in relatives may reflect increased inhibition. Impaired response inhibition in OCD has been demonstrated in several studies and might contribute to impairments in suppressing compulsive actions. Thus, increased inferior frontal gyrus activity in the unaffected relatives of patients with OCD may have contributed to protection from symptom development., (© 2021 The Authors.)

Background: Benzodiazepines have reliable adverse effects on saccadic eye movements, but the impact of sex as a potential modulator of these effects is less clear. A recent study reported stronger adverse effects on the spatial consistency of saccades in females, which may reflect sex differences in cerebellar mechanisms., Aims: We aimed to further examine the role of sex as a potential modulator of benzodiazepine effects by employing the saccadic adaptation paradigm, which is known to be sensitive to cerebellar functioning., Methods: A total of n =50 healthy adults performed a horizontal step prosaccade task and a saccadic adaptation task under 0.5 mg lorazepam, 1 mg lorazepam and placebo in a double-blind, within-subjects design., Results: In the prosaccade task, lorazepam had adverse effects on measures of peak velocity, latency and spatial consistency. The administration of 0.5 mg lorazepam led to significant reductions in gain-decrease adaptation, while a dose of 1 mg did not impair adaptation learning. Gain-increase adaptation was generally less pronounced, and unaffected by the drug. There were no significant drug×sex interactions in either task., Conclusions: We conclude that a low dose of lorazepam impairs gain-decrease adaptation independent of sex. At higher doses, however, increasing fatigue may facilitate adaptation and thus counteract the adverse effects observed at lower doses. With regards to prosaccades, our findings confirm peak velocity as well as latency and spatial measures as sensitive biomarkers of GABAergic effects.

Objective: Obsessive-compulsive disorder (OCD) is a complex psychiatric disorder with a substantial genetic contribution. While the specific variants underlying OCD's heritability are still unknown, findings from genome-wide association studies (GWAS) corroborate the importance of common SNPs explaining the phenotypic variance in OCD. Investigating associations between the genetic liability for OCD, as reflected by a polygenic risk score (PRS), and potential endophenotypes of the disorder, such as the personality trait harm avoidance, may aid the understanding of functional pathways from genes to diagnostic phenotypes., Methods: We derived PRS for OCD at several P-value thresholds based on the latest Psychiatric Genomics Consortium OCD GWAS (2688 cases, 7037 controls) in an independent sample of OCD patients (n = 180), their unaffected first-degree relatives (n = 108) and healthy controls (n = 200). Using linear regression, we tested whether these PRS are associated with the personality trait harm avoidance., Results: Results showed that OCD PRS significantly predicted OCD status, with patients having the highest scores and relatives having intermediate scores. Furthermore, the genetic risk for OCD was associated with harm avoidance across the entire sample, and among OCD patients. As indicated by mediation analyses, harm avoidance mediated the association between the OCD PRS and OCD caseness. These results were observed at multiple P-value thresholds and persisted after the exclusion of patients with a current comorbid major depressive or anxiety disorder., Conclusion: Our findings support the polygenic nature of OCD and further validate harm avoidance as a candidate endophenotype and diathesis of OCD., (© 2020 The Authors. Acta Psychiatrica Scandinavica published by John Wiley & Sons Ltd.)

Seventeen-day-old twins were hospitalized for neonatal herpes simplex virus 1 (HSV-1) with central nervous system disease and internal capsule and thalamic lesions on magnetic resonance imaging (MRI). They were treated with the usual intravenous (IV) treatment and oral therapy for 6 months. The clinical course was good in both children with negative HSV polymerase chain reaction on completion of IV therapy. The neurological condition recurred in one child with new radiological lesions at 7 months of age, 2 weeks after discontinuation of oral treatment. Cerebral lesions highlighted on the MRI scan are specific to the neonatal period and impact long-term prognosis. The likely genetic predisposition in this case is interesting and requires further investigation. In addition, this case raises questions about the duration of oral acyclovir suppressive therapy., Competing Interests: None declared., (Georg Thieme Verlag KG Stuttgart · New York.)

The identification of the most efficient method for whole central nervous system targeting that is translatable to humans and the safest route of adeno-associated virus (AAV) administration is a major concern for future applications in clinics. Additionally, as many AAV serotypes were identified for gene introduction into the brain and the spinal cord, another key to human gene-therapy success is to determine the most efficient serotype. In this study, we compared lumbar intrathecal administration through catheter implantation and intracerebroventricular administration in the cynomolgus macaque. We also evaluated and compared two AAV serotypes that are currently used in clinical trials: AAV9 and AAVrh10. We demonstrated that AAV9 lumbar intrathecal delivery using a catheter achieved consistent transgene expression in the motor neurons of the spinal cord and in the neurons/glial cells of several brain regions, whereas AAV9 intracerebroventricular delivery led to a consistent transgene expression in the brain. In contrast, AAVrh10 lumbar intrathecal delivery led to rare motor neuron targeting. Finally, we found that AAV9 efficiently targets respiratory and skeletal muscles after injection into the cerebrospinal fluid (CSF), which represents an outstanding new property that can be useful for the treatment of diseases affecting both the central nervous system and muscle., (© 2020.)

Background: Increased neural error-signals have been observed in obsessive-compulsive disorder (OCD), anxiety disorders, and inconsistently in depression. Reduced neural error-signals have been observed in substance use disorders (SUD). Thus, alterations in error-monitoring are proposed as a transdiagnostic endophenotype. To strengthen this notion, data from unaffected individuals with a family history for the respective disorders are needed., Methods: The error-related negativity (ERN) as a neural indicator of error-monitoring was measured during a flanker task from 117 OCD patients, 50 unaffected first-degree relatives of OCD patients, and 130 healthy comparison participants. Family history information indicated, that 76 healthy controls were free of a family history for psychopathology, whereas the remaining had first-degree relatives with depression (n = 28), anxiety (n = 27), and/or SUD (n = 27)., Results: Increased ERN amplitudes were found in OCD patients and unaffected first-degree relatives of OCD patients. In addition, unaffected first-degree relatives of individuals with anxiety disorders were also characterized by increased ERN amplitudes, whereas relatives of individuals with SUD showed reduced amplitudes., Conclusions: Alterations in neural error-signals in unaffected first-degree relatives with a family history of OCD, anxiety, or SUD support the utility of the ERN as a transdiagnostic endophenotype. Reduced neural error-signals may indicate vulnerability for under-controlled behavior and risk for substance use, whereas a harm- or error-avoidant response style and vulnerability for OCD and anxiety appears to be associated with increased ERN. This adds to findings suggesting a common neurobiological substrate across psychiatric disorders involving the anterior cingulate cortex and deficits in cognitive control.

Patients with obsessive-compulsive disorder (OCD) show dysfunctions of the fronto-striatal circuitry, which imply corresponding oculomotor deficits including smooth pursuit eye movements (SPEM). However, evidence for a deficit in SPEM is inconclusive, with some studies reporting reduced velocity gain while others did not find any SPEM dysfunctions in OCD patients. Interestingly, psychosis-like traits have repeatedly been linked to both OCD and impaired SPEM. Here, we examined a large sample of n = 168 patients with OCD, n = 93 unaffected first-degree relatives and n = 171 healthy control subjects to investigate whether elevated levels of schizotypy and SPEM deficits represent potential endophenotypes of OCD. We applied a SPEM task with high demands on predictive pursuit that is more sensitive to assess executive dysfunctions than a standard task with continuous visual feedback, as episodes of target blanking put increased demands on basal ganglia and prefrontal involvement. Additionally, we examined the relation between schizotypy and SPEM performance in OCD patients and their relatives. Results indicate that OCD patients and unaffected relatives do not show deficient performance in either standard or predictive SPEM. Yet, both patients and relatives exhibited elevated levels of schizotypy, and schizotypy was significantly correlated with velocity gain during standard trials in unmedicated and depression-free OCD patients. These findings highlight the role of schizotypy as a candidate endophenotype of OCD and add to the growing evidence for predisposing personality traits in OCD. Furthermore, intact gain may represent a key characteristic that distinguishes the OCD and schizophrenia patient populations.

Increasing evidence indicates that patients with obsessive-compulsive disorder (OCD) exhibit alterations in fronto-striatal circuitry. Performance deficits in the antisaccade task would support this model, but results from previous small-scale studies have been inconclusive as either increased error rates, prolonged antisaccade latencies, both or neither have been reported in OCD patients. In order to address this issue, we investigated antisaccade performance in a large sample of OCD patients ( n = 169) and matched control subjects ( n = 183). As impaired antisaccade performance constitutes a potential endophenotype of OCD, unaffected first-degree relatives of OCD patients ( n = 100) were assessed, as well. Furthermore, we conducted a quantitative meta-analysis to integrate our data with previous findings. In the empirical study, OCD patients exhibited significantly increased antisaccade latencies, intra-subject variability (ISV) of antisaccade latencies, and antisaccade error rates. The latter effect was driven by errors with express latency (80-130 ms), as patients did not differ significantly from controls with regards to regular errors (>130 ms). Notably, unaffected relatives of OCD patients showed elevated antisaccade express error rates and increased ISV of antisaccade latencies, as well. Antisaccade performance was not associated with state anxiety within groups. Among relatives, however, we observed a significant correlation between antisaccade error rate and harm avoidance. Medication status of OCD patients, symptom severity, depressive comorbidity, comorbid anxiety disorders and OCD symptom dimensions did not significantly affect antisaccade performance. Meta-analysis of 10 previous and the present empirical study yielded a medium-sized effect ( SMD = 0.48, p < 0.001) for higher error rates in OCD patients, while the effect for latencies did not reach significance owing to strong heterogeneity ( SMD = 0.51, p = 0.069). Our results support the assumption of impaired antisaccade performance in OCD, although effects sizes were only moderately large. Furthermore, we provide the first evidence that increased antisaccade express error rates and ISV of antisaccade latencies may constitute endophenotypes of OCD. Findings regarding these more detailed antisaccade parameters point to potentially underlying mechanisms, such as early pre-stimulus inhibition of the superior colliculus.

Patients with obsessive-compulsive disorder (OCD) show deficient planning capacity in the Tower of London (TOL) problem solving task. Preliminary evidence for similar deficits in unaffected first-degree relatives suggests that impaired planning may constitute an endophenotype of OCD. However, results on this issue are inconsistent, possibly owing to small sample sizes and variability in problem structure across TOL tasks. Here, we adopted a computerized version of the TOL task featuring a 2 × 2 factorial design (high/low search depth × full/partial tower goal state) and examined a well-characterized sample of n = 72 OCD patients, n = 76 unaffected first-degree relatives and n = 102 healthy comparison subjects. Both OCD patients and relatives exhibited significantly less accurate problem solving than controls. Search depth, goal hierarchy, or the number of minimum moves did not moderate these group differences. Medication, OCD symptoms, and depressive comorbidity did not affect TOL performance in patients, suggesting a state-independent effect. In conclusion, we found that OCD patients as well as unaffected first-degree relatives show deficient TOL performance across a range of task conditions, strongly supporting the role of impaired planning as an endophenotype of OCD, and contributing to the growing evidence for fronto-striatal dysfunctions in OCD., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Repeated drug use modifies the emotional and cognitive processing of drug-associated cues. These changes are supposed to persist even after prolonged abstinence. Several studies demonstrated that smoking cues selectively attract the attention of smokers, but empirical evidence for such an attentional bias among successful quitters is inconclusive. Here, we investigated whether attentional biases persist after smoking cessation. Thirty-eight former smokers, 34 current smokers, and 29 non-smokers participated in a single experimental session. We used three measures of attentional bias for smoking stimuli: A visual probe task with short (500ms) and long (2000ms) picture stimulus durations, and a modified Stroop task with smoking-related and neutral words. Former smokers and current smokers, as compared to non-smokers, showed an attentional bias in visual orienting to smoking pictures in the 500ms condition of the visual probe task. The Stroop interference index of smoking words was negatively related to nicotine dependence in current smokers. Former smokers and mildly dependent smokers, as compared to non-smokers, showed increased interference by smoking words in the Stroop task. Neither current nor former smokers showed an attentional bias in maintained attention (2000ms visual probe task). In conclusion, even after prolonged abstinence smoking cues retain incentive salience in former smokers, who differed from non-smokers on two attentional bias indices. Attentional biases in former smokers operate mainly in early involuntary rather than in controlled processing, and may represent a vulnerability factor for relapse. Therefore, smoking cessation programs should strengthen self-control abilities to prevent relapses., (Copyright © 2017 Elsevier B.V. and ECNP. All rights reserved.)

Previous research in patients with obsessive-compulsive disorder (OCD) has indicated performance decrements in working memory (WM) and response inhibition. However, underlying neural mechanisms of WM deficits are not well understood to date, and empirical evidence for a proposed conceptual link to inhibition deficits is missing. We investigated WM performance in a numeric n-back task with four WM load conditions during functional Magnetic Resonance Imaging (fMRI) in 51 patients with OCD and 49 healthy control participants who were matched for age, sex, and education. Additionally, a stop signal task was performed outside the MRI scanner in a subsample. On the behavioral level, a significant WM load by group interaction was found for both accuracy (p < 0.02) and reaction time measures (p < 0.03), indicating increased reaction times as well as reduced accuracy specifically at high WM load (3-back) in patients with OCD. Whole-brain analyses of fMRI-data identified neural correlates of a load-dependent WM decrement in OCD in the supplementary motor area (SMA) and the inferior parietal lobule (IPL). Within the OCD sample, SMA-activity as well as n-back performance were correlated with stop signal task performance. Results from behavioral and fMRI-analyses indicate a reduced WM load-dependent modulation of neural activity in OCD and suggest a common neural mechanism for inhibitory dysfunction and WM decrements in OCD.

Recent evidence indicates that patients with obsessive-compulsive disorder (OCD) as well as their unaffected first-degree relatives show deficits in the volitional control of saccades, suggesting that volitional saccade performance may constitute an endophenotype of OCD. Here, we aimed to replicate and extend these findings in a large, independent sample. One hundred and fifteen patients with OCD, 103 healthy comparison subjects without a family history of OCD, and 31 unaffected first-degree relatives of OCD patients were examined using structured clinical interviews and performed a volitional saccade task as well as a prosaccade task. In contrast to previous reports, neither patients nor relatives showed impairments in the performance of volitional saccades compared to healthy controls. Notably, medicated patients did not differ from nonmedicated patients, and there was no effect of depressive comorbidity. Additional analyses investigating correlations between saccade performance and OCD symptom dimensions yielded no significant associations. In conclusion, the present results do not support the notion that volitional saccade execution constitutes an endophenotype of OCD. Possible explanations for inconsistencies with previous studies are discussed., (© 2017 Society for Psychophysiological Research.)

Frontal electroencephalographic alpha asymmetry as an indicator of trait approach and trait inhibition systems has previously been studied in individuals with obsessive-compulsive disorder (OCD) with mixed results. We explored frontal alpha asymmetry as a possible risk factor in OCD by investigating a large sample of OCD patients (n = 113), healthy control participants (n = 113), and unaffected 1st-degree relatives of OCD patients (n = 37). Additionally, the relationship between OCD symptom dimensions and frontal alpha asymmetry was explored. OCD patients and healthy control participants did not differ in alpha asymmetry scores. Hence, the current results do not support the notion that OCD as a diagnostic entity is associated with a shift in frontal cortical activity. Furthermore, alpha asymmetry scores were not statistically related to specific OCD symptom dimensions. Reasons for inconsistent results in OCD are discussed and should be explored in future studies. Compared to OCD patients and healthy control participants, unaffected 1st-degree relatives of OCD patients showed increased left frontal activity. Such asymmetry has previously been found to be associated with positive affect and adaptive emotion regulation under stress. Because stressful life events play an important role in the onset and exacerbation of OCD, increased left frontal activity might serve as a resilience factor in unaffected 1st-degree relatives. Future studies should follow up on these results with longitudinal risk studies and pre- and posttherapy assessments to further explore causality of this putative factor. (PsycINFO Database Record, ((c) 2017 APA, all rights reserved).)

Adeno-associated virus (AAV) gene therapy constitutes a powerful tool for the treatment of neurodegenerative diseases. While AAVs are generally administered systemically to newborns in preclinical studies of neurological disorders, in adults the maturity of the blood-brain barrier (BBB) must be considered when selecting the route of administration. Delivery of AAVs into the cerebrospinal fluid (CSF) represents an attractive approach to target the central nervous system (CNS) and bypass the BBB. In this study, we investigated the efficacy of intra-CSF delivery of a single-stranded (ss) AAV9-CAG-GFP vector in adult mice via intracisternal (iCist) or intralumbar (it-Lumb) administration. It-Lumb ssAAV9 delivery resulted in greater diffusion throughout the entire spinal cord and green fluorescent protein (GFP) expression mainly in the cerebellum, cortex and olfactory bulb. By contrast, iCist delivery led to strong GFP expression throughout the entire brain. Comparison of the transduction efficiency of ssAAV9-CAG-GFP versus ssAAV9-SYN1-GFP following it-Lumb administration revealed widespread and specific GFP expression in neurons and motoneurons of the spinal cord and brain when the neuron-specific synapsin 1 (SYN1) promoter was used. Our findings demonstrate that it-Lumb ssAAV9 delivery is a safe and highly efficient means of targeting the CNS in adult mice.

Objective: The etiology of obsessive-compulsive disorder (OCD) is assumed to involve interactions between genetically determined vulnerability factors and significant environmental features. Here, we aim to investigate how the personality trait harm avoidance and the experience of childhood adversities contribute to OCD., Method: A total of 169 patients with OCD, 157 healthy comparison subjects, and 57 unaffected first-degree relatives of patients with OCD participated in the study. Harm avoidance was assessed using the Temperament and Character Inventory, and the severity of childhood adversities was measured with the Childhood Trauma Questionnaire., Results: Both patients with OCD and relatives showed elevated levels of harm avoidance compared to controls. Furthermore, patients exhibited significantly higher scores than relatives. This linear pattern was observed throughout all subscales of harm avoidance, and remained stable after controlling for the severity of depressive and obsessive-compulsive symptoms. With regard to childhood adversities, patients with OCD reported higher levels than relatives and controls., Conclusion: Our results provide further evidence for a diathesis-stress model of OCD. While patients and unaffected relatives share elevated levels of harm avoidance, supporting the role of harm avoidance as an endophenotype of OCD, a heightened severity of childhood adversity was only observed in patients. The assumed biological underpinnings of these findings are discussed., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Retrospective studies suggest that early hypoproteinemia has prognostic value for adverse outcome in preemies, but the underlying pathophysiology is unknown. We hypothesized that the prognostic relevance of hypoproteinemia could be related to its association with impaired cardiovascular function and organ perfusion during transition., Objectives: To describe the plasma protein status and the measures of cardiovascular function according to the outcome in infants <32 weeks' gestation., Methods: One hundred and twenty-eight infants were prospectively included from birth to discharge. During the first 24 h of life, we assessed the cardiovascular function and systemic and organ blood flow by Doppler ultrasound, and monitored cerebral and renal regional oxygen saturation (cRSO2, rRSO2) using near-infrared spectroscopy. These measures were analyzed in relationship to hypoproteinemia (total plasma protein level <40 g/L at 12 h of life) and severe adverse outcome (death or survival with severe neurological injury)., Results: Hypoproteinemia was associated with a higher risk of a severe adverse outcome after adjustment of confounding variables (adjusted OR = 6.8; 95% CI 1.3-34). Compared to normoproteinemic infants and after adjustment for gestational age, hypoproteinemic ones had more significantly: hypotension (7 vs. 13%, p = 0.03), abnormal capillary refilling time (20 vs. 36%, p < 0.001), abnormal renal blood flow (resistive index 0.78 ± 0.11 vs. 0.85 ± 0.09, p = 0.04), lower rRSO2 (82.9 ± 9.2 vs. 73.6 ± 10.5%, p = 0.04), and lower systemic vascular resistance (0.155 ± 0.058 vs. 0.108 ± 0.037 mm Hg/L/kg; p = 0.04). The cRSO2 patterns were significantly decreased in infants with severe adverse outcome and independent from protein status., Conclusion: Hypoproteinemia is associated with impaired cardiovascular function. Further studies are required to elucidate the interplay between changes in protein levels, postnatal hemodynamics and clinical outcome., (© 2017 S. Karger AG, Basel.)

Alterations in DNA methylation have been associated with cognitive decline and Alzheimer's disease. A recent study of mild cognitive impairment (MCI) reported a significant association between annual decline in cognitive function and the rs11887120 SNP located in DNMT3A, a gene implicated in DNA methylation. Here, we aimed to replicate this finding in two independent MCI cohorts (n = 1024); however, no significant association was observed in either cohort or the pooled dataset. In stratified analyses for conversion to Alzheimer's disease status, no association between rs11887120 and cognitive decline was observed in either converters or nonconverters. In conclusion, our analyses provide no support for the hypothesis that genetic variants in DNMT3A are implicated in cognitive performance decline in individuals with MCI.

Harm avoidance is a personality trait characterized by excessive worrying and fear of uncertainty, which has repeatedly been related to anxiety disorders. Converging lines of research in rodents and humans point towards an involvement of the nicotinic cholinergic system in the modulation of anxiety. Most notably, the rs1044396 polymorphism in the CHRNA4 gene, which codes for the α4 subunit of the nicotinic acetylcholine receptor, has been linked to negative emotionality traits including harm avoidance in a recent study. Against this background, we investigated the association between harm avoidance and the rs1044396 polymorphism using data from N=1673 healthy subjects, which were collected in the context of the German multi-centre study ׳Genetics of Nicotine Dependence and Neurobiological Phenotypes׳. Homozygous carriers of the C-allele showed significantly higher levels of harm avoidance than homozygous T-allele carriers, with heterozygous subjects exhibiting intermediate scores. The effect was neither modulated by age or gender nor by smoking status. By replicating previous findings in a large population-based sample for the first time, the present study adds to the growing evidence suggesting an involvement of nicotinic cholinergic mechanism in anxiety and negative emotionality, which may pose an effective target for medical treatment., (Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.)

The proneness to minor errors and slips in everyday life as assessed by the Cognitive Failures Questionnaire (CFQ) constitutes a trait characteristic and is reflected in stable features of brain structure and function. It is unclear, however, how dynamic interactions of large-scale brain networks contribute to this disposition. To address this question, we performed a high model order independent component analysis (ICA) with subsequent dual regression on resting-state fMRI data from 71 subjects to extract temporal time courses describing the dynamics of 17 resting-state networks (RSN). Dynamic network interactions between all 17 RSN were assessed by linear correlations between networks' time courses. On this basis, we investigated the relationship between subject-level RSN interactions and the susceptibility to everyday cognitive failure. We found that CFQ scores were significantly correlated with the interplay of the cingulo-opercular network (CON) and a posterior parietal network which unifies clusters in the posterior cingulate, precuneus, intraparietal lobules and middle temporal regions. Specifically, a higher positive functional connectivity between these two RSN was indicative of higher proneness to cognitive failure. Both the CON and posterior parietal network are implicated in cognitive functions, such as tonic alertness and executive control. Results indicate that proper checks and balances between the two networks are needed to protect against cognitive failure. Furthermore, we demonstrate that the study of temporal network dynamics in the resting state is a feasible tool to investigate individual differences in cognitive ability and performance., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Introduction: It has been hypothesized that two distinctive forms of Internet addiction exist. Here, generalized Internet addiction refers to the problematic use of the Internet covering a broad range of Internet-related activities. In contrast, specific forms of Internet addiction target the problematic use of distinct online activities such as excessive online video gaming or activities in social networks., Methods: The present study investigates the relationship between generalized and specific Internet addiction in a cross-cultural study encompassing data from China, Taiwan, Sweden and Germany in n = 636 participants. In this study, we assessed - besides generalized Internet addiction - addictive behavior in the domains of online video gaming, online shopping, online social networks and online pornography., Results: The results confirm the existence of distinct forms of specific Internet addiction. One exception, however, was established in five of the six samples under investigation: online social network addiction correlates in large amounts with generalized Internet addiction., Discussion: In general, it is of importance to distinguish between generalized and specific Internet addiction., (Copyright © 2014 Wiley Publishing Asia Pty Ltd.)

Background: Evaluation of the right ventricle (RV) using transthoracic echocardiography is challenging in patients with repaired tetralogy of Fallot (rTOF)., Aims: To evaluate the accuracy of conventional echocardiographic variables and real-time three-dimensional echocardiography (RT3DE) in assessing right ventricular (RV) volumes and function compared with magnetic resonance imaging (MRI), in adult patients with rTOF and referred for pulmonary valve replacement (PVR)., Methods: Complete echocardiography was performed on 26 consecutive patients referred for PVR, before and 1 year after surgery. All variables were compared with MRI., Results: Correlations between conventional variables and MRI were absent or poor when assessing RV ejection fraction (RVEF), except for fractional area of change (FAC; r=0.70, P<0.01 before PVR; r=0.68, P<0.01 after PVR) and RT3DE (r=0.96, P<0.01 before PVR; r=0.98, P<0.01 after PVR). The RV volume correlation between RT3DE and MRI was excellent before and after surgery for RV end-diastolic volume (r=0.88, P<0.01 and r=0.91, P<0.01, respectively) and RV end-systolic volume (r=0.92, P<0.01 and r=0.95, P<0.01, respectively). The accuracy of these indices, as a diagnostic test for impaired RV (<45%), was good: Youden's indexes varied from 0.47 to 0.89; areas under the receiver operating characteristic curve before and after PVR were 0.86 and 0.81 for FAC and 0.98 and 0.97 for RT3DE, respectively., Conclusion: Commonly used echocardiography variables, such as tricuspid annular plane systolic excursion and tricuspid annular peak systolic velocity, did not sensitively evaluate global RVEF. A global approach, that includes the whole RV and integration of its different components, was more reliable in patients with rTOF., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Objectives: This study compares the prevalence and perinatal mortality of congenital heart defects on La Réunion with European (EUROCAT) standards., Methods and Results: Data were extracted from a EUROCAT-affiliated congenital malformations registry, covering 88,025 births during the period 2002-2007, on the whole island territory. A total of 512 congenital heart defects were registered, including 424 live births, 18 foetal deaths from 16 weeks of gestation, and 70 terminations of pregnancy. The total prevalence of congenital heart defects was 5.8 per 1000 births and live birth prevalence was 4.8 per 1000. The total prevalence of non-chromosomal congenital heart defects was 5.1 per 1000 births, of which 3% were perinatal deaths, 33.3% prenatally diagnosed, and 11.6% termination of pregnancy. Severe non-chromosomal congenital heart defects - excluding ventricular septal defects, atrial septal defects, and pulmonary valve stenosis - occurred in 2.1 per 1000 births, of which 10.3% were perinatal deaths, 59.1% prenatally diagnosed, and 24.3% termination of pregnancy. Of the severe congenital heart defects, the rates of single ventricle (0.20‰), Ebstein anomaly (0.11‰), common arterial trunk (0.25‰), and atrioventricular septal defect (0.62‰) exceeded averages found in Europe, although coarctation of the aorta was infrequent. Conversely, rates of ventricular septal defects, atrial septal defects, and pulmonary valve stenosis were inferior to European standards. Slightly less than half of the congenital heart defects of chromosomal origin were associated with Down syndrome., Conclusion: In La Réunion, the total prevalence of congenital heart defects is far inferior to that found in Europe. The difference can be attributable to lower prevalences of mild congenital heart defects.

A 10-year-old child was hospitalized for bradycardia during a viral infection with chikungunya. His history showed unexplored episodes of bradycardia. Cardiologic explorations revealed cardiac sinus node dysfunction (SD). Mutational screening of the SCN5A gene showed that this case was a compound heterozygote for p.Ala735Val and p.Asp1792Asn missense mutants. Five years later, the child underwent a pacemaker insertion after an electrophysiological study performed during an atrial flutter access., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Congenital bronchial stenosis is a very rare cause of neonatal dyspnea. Surgical management remains challenging in small children. We report successful implantation of a bronchial stent in a 3-month-old female infant presenting with congenital right bronchial stenosis and 18 months of follow-up. Use of stents in children remains controversial because of the problem of size mismatch as the child grows. Nevertheless, expandable stent implantation could be an interesting alternative to complex surgery for localized bronchial stenosis in neonates., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Subgaleal hematoma in the newborn infant is rare, occurs early, and often bears serious consequences. We report on 2 subacute cases of bruising of the scalp that occurred following the use of a suction cup. Emergency treatment consisted of a transfusion of packed red blood cells and fresh frozen plasma. Children born by use of vacuum extractor or forceps require careful monitoring by the nursing staff throughout their stay in the maternity unit., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Three infants aged less than 2 months were hospitalized for malignant pertussis. Echocardiography showed pulmonary hypertension. High-frequency oscillations and nitric oxide were ineffective. Respiratory and hemodynamic conditions deteriorated secondarily. The third case received an exchange transfusion without success. All three infants died following multiorgan failure. Malignant pertussis is the leading cause of infectious death in infants less than 2 months of age, treatment is often ineffective, and prevention, targeting the population of young adults, is particularly important., (Copyright 2009 Elsevier Masson SAS. All rights reserved.)

Objectives: The aim of this study was to describe the incidence of early onset neonatal infections (EONI) in the southern part of the Reunion Island, and to study the application of ANAES criteria., Patients and Methods: A cross-sectional study was made of data collected for all live births having occurred between 1st January 2001 and 31st December 2004., Results: Four hundred and thirty-seven in 16,071 neonates (out of 21,231 live births) presented with a certain or probable EONI, accounting for a regional rate of 20 per thousand (CI95 % 18-23 per thousand). Among 437 EONIs, group B streptococcus (GBS) was reported in 70.5% of the cases (n=308), Gram negative bacteria in 19.9% (n=87), of which nearly two thirds of Escherichia coli (n=56). Applying ANAES criteria led to identify 380 EONIs among 437 proven infections (sensitivity: 87%, specificity: 26%). A logistic regression analysis identified eight EONI predictors for the 7015 neonates for whom the mother GBS screening was documented: GBS positive vaginal culture (OR 4.2; CI95% 3.3-5.4), unexplained preterm birth less than 35 weeks (OR 5.7; CI95% 3.7-8.7), prolonged rupture of membranes greater than or equal to 18 hours (OR 2.1; CI95% 1.4-3.0), maternal fever greater than or equal to 37.8 degrees C (OR 3.2; CI95% 2.3-4.5), fetal tachycardia greater than or equal to 160 ppm (OR 2.7; CI95% 1.8-4.0), and thin (OR 1.6; CI95% 1.2-2.1) or thick meconium-stained amniotic fluid (OR 3.0; CI95% 2.1-4.5) or fetid fluid (OR 14.8; CI95% 4.2-51.8)., Conclusion: The incidence of EONIS far exceeded that observed in metropolitan France, and the ANAES criteria lack sensitivity and specificity.

Factor XIII deficiency is an uncommon inherited disorder which is characterized by umbilical cord bleeding and an unusually high incidence of intracranial hemorrhage. We report here a case of Factor XIII deficiency in a child that presented a caput. succedaneum as the first manifestation of the disease and then an umbilical cord bleeding. The importance of performing a quantitative FXIII assay in the presence of strong clinical suspicion is strengthened because of the normality of the standard screening tests and the important therapeutic consequences.

Botulism was suspected in a 17-day-old breastfed infant who developed over 2 days progressive muscular weakness and hypoventilation. The patient also presented with pupil dilation and light unresponsiveness. The electroencephalogram was normal. Full recovery was obtained after 85 days of artificial ventilation. Diagnosis was confirmed by the presence of the botulin toxin B in the patient serum. The source of the infection was not identified.

Glycosylation represents an attractive target for protein engineering of novel antibiotics, because specific attachment of one or more deoxysugars is required for the bioactivity of many antibiotic and antitumour polyketides. However, proper assessment of the potential of these enzymes for such combinatorial biosynthesis requires both more precise information on the enzymology of the pathways and also improved Escherichia coli-actinomycete shuttle vectors. New replicative vectors have been constructed and used to express independently the dnmU gene of Streptomyces peucetius and the eryBVII gene of Saccharopolyspora erythraea in an eryBVII deletion mutant of Sac. erythraea. Production of erythromycin A was obtained in both cases, showing that both proteins serve analogous functions in the biosynthetic pathways to dTDP-L-daunosamine and dTDP-L-mycarose, respectively. Over-expression of both proteins was also obtained in S. lividans, paving the way for protein purification and in vitro monitoring of enzyme activity. In a further set of experiments, the putative desosaminyltransferase of Sac. erythraea, EryCIII, was expressed in the picromycin producer Streptomyces sp. 20032, which also synthesises dTDP-D-desosamine. The substrate 3-alpha-mycarosylerythronolide B used for hybrid biosynthesis was found to be glycosylated to produce erythromycin D only when recombinant EryCIII was present, directly confirming the enzymatic role of EryCIII. This convenient plasmid expression system can be readily adapted to study the directed evolution of recombinant glycosyltransferases.

The production of erythromycin A by Saccharopolyspora erythraea requires the synthesis of dTDP-D-desosamine and dTDP-L-mycarose, which serve as substrates for the transfer of the two sugar residues onto the macrolactone ring. The enzymatic activities involved in this process are largely encoded within the ery gene cluster, by two sets of genes flanking the eryA locus that encodes the polyketide synthase. We report here the nucleotide sequence of three such ORFs located immediately downstream of eryA, ORFs 7, 8 and 9. Chromosomal mutants carrying a deletion either in ORF7 or in one of the previously sequenced ORFs 13 and 14 have been constructed and shown to accumulate erythronolide B, as expected for eryB mutants. Similarly, chromosomal mutants carrying a deletion in either ORF8, ORF9, or one of the previously sequenced ORFs 17 and 18 have been constructed and shown to accumulate 3-alpha-mycarosyl erythronolide B, as expected for eryC mutants. The ORF13 (eryBIV), ORF17 (eryCIV) and ORF7 (eryBII) mutants also synthesised small amounts of macrolide shunt metabolites, as shown by mass spectrometry. These results considerably strengthen previous tentative proposals for the pathways for the biosynthesis of dTDP-D-desosamine and dTDP-L-mycarose in Sac. erythraea and reveal that at least some of these enzymes can accommodate alternative substrates.

A promoter which controls expression of the pristinamycin multidrug resistance gene (ptr) in Streptomyces pristinaspiralis could be induced by physiological stresses in both Streptomyces spp. and Escherichia coli. In S. pristinaspiralis, the ptr promoter (Pptr) was induced by pristinamycin I (PI) or pristinamycin II (PII). Streptomyces lividans was adopted as a convenient heterologous host for studies of Pptr regulation since it has no known pristinamycin biosynthetic genes. Two key regulatory features were documented in these studies: many (19 of 70) antibiotics and chemicals with no common targets or structural features induced the Pptr; induction with PI was most efficient during a transition phase when antibiotic biosynthetic genes are switched on. In Streptomyces coelicolor, Pptr activity was similarly inducible by PI and not dependent on sigma factors HrdA, HrdC, or HrdD. In E. coli, Pptr cloned in the bifunctional promoter probe vector pIJ2839 was functional and activated upon entry into stationary phase in the absence of exogenous inducer. Finally, gel-retardation studies demonstrated a Pptr-binding protein in S. lividans (where its activity was PI-inducible), S. coelicolor and S. pristinaespiralis. The fact that this activity was not detected in E. coli suggested the existence of another regulatory system perhaps also present in Streptomyces.

A promoter controlling expression of the pristinamycin multidrug resistance gene (ptr), originally isolated from Streptomyces pristinaespiralis, is inducible by many toxic compounds in various Streptomyces species. Studies of ptr promoter control were carried out in the heterologous host, Streptomyces lividans. In S. lividans, a regulatory protein or a protein complex (Pip), identified by its ability to bind to the ptr promoter in gel-retardation experiments, was induced by pristinamycin I (PI). In situ copper-phenanthroline footprinting analysis identified three (A, B, and C) similar Pip-binding sites having the sequence GTACA(C/G)CGTA(C/T). These sites overlapped with functionally important regions of the promoter: the 'A' site overlapped with the -35 hexamer, 'B' overlapped with the -10 hexamer and 'C' was located between the transcription start site and the Shine-Dalgarno sequence. A GT-AG dinucleotide mutation was introduced at positions 8-9 of the consensus sequence to generate seven variant promoters: three mutated in one of the three sites, three mutated in two sites, and one mutated in all three sites. Whereas these promoters had reduced antibiotic (PI)-induced activity, their levels of expression in the absence of PI was higher. This suggested an unusual regulatory mechanism in which Pip could act either as an activator or repressor. Gel shift experiments revealed Pip or its homologues in many other Streptomyces species, suggesting that it is widely employed in the regulation of antibiotic resistance genes and perhaps secondary metabolism.

A multidrug resistance gene (mdr) has been cloned from Streptomyces pristinaespiralis, a producer of two antibiotics having synergistic activities together known as pristinamycin. This gene, ptr, provides resistance not only to two structurally dissimilar compounds (pristinamycin I, PI; pristinamycin II, PII) and the natural pristinamycin mixture but also to rifampicin. Mutagenesis and subcloning of ptr localized it to a 2 kb region which was sequenced and analyzed. It contained an open reading frame of 1506 bp which encoded a putative membrane protein with 14 hydrophobic domains, and showed sequence similarity to a superfamily of bacterial proteins that employ transmembrane electrochemical gradients to catalyse active efflux of various antibiotics and toxic compounds. Ptr was most similar to a subfamily which included other mdr genes and antibiotic transport genes associated with antibiotic biosynthetic gene clusters in actinomycetes. In vitro coupled transcription-translation experiments were used to identify the ptr gene product. Analysis of the upstream region did not reveal a divergently transcribed repressor gene, as is the case for several related resistance determinants involved in antibiotic transport, suggesting that ptr is regulated by a different mechanism. Transcriptional analyses of this gene, carried out in both S. pristinaespiralis and Streptomyces lividans, indicated the same transcriptional start point and predicted -10 and -35 hexamers which were somewhat similar to Streptomyces vegetative-type promoters.