Interests, Motives, and Psychological Burdens in Times of Crisis and Lockdown: Google Trends Analysis to Inform Policy Makers.

BACKGROUND: In the face of the COVID-19 pandemic, the German government and the 16 German federal states implemented a variety of nonpharmaceutical interventions (NPIs) to decelerate the spread of the SARS-CoV-2 virus and thus prevent a collapse of the health care system. These measures comprised, among others, social distancing, the temporary closure of shops and schools, and a ban of large public gatherings and meetings with people not living in the same household. OBJECTIVE: It is fair to assume that the issued NPIs have heavily affected social life and psychological functioning. We therefore aimed to examine possible effects of this lockdown in conjunction with daily new infections and the state of the national economy on people's interests, motives, and other psychological states. METHODS: We derived 249 keywords from the Google Trends database, tapping into 27 empirically and rationally selected psychological domains. To overcome issues with reliability and specificity of individual indicator variables, broad factors were derived by means of time series factor analysis. All domains were subjected to a change point analysis and time series regression analysis with infection rates, NPIs, and the state of the economy as predictors. All keywords and analyses were preregistered prior to analysis. RESULTS: With the pandemic arriving in Germany, significant increases in people's search interests were observed in virtually all domains. Although most of the changes were short-lasting, each had a distinguishable onset during the lockdown period. Regression analysis of the Google Trends data confirmed pronounced autoregressive effects for the investigated variables, while forecasting by means of the tested predictors (ie, daily new infections, NPIs, and the state of economy) was moderate at best. CONCLUSIONS: Our findings indicate that people's interests, motives, and psychological states are heavily affected in times of crisis and lockdown. Specifically, disease- and virus-related domains (eg, pandemic disease, symptoms) peaked early, whereas personal health strategies (eg, masks, homeschooling) peaked later during the lockdown. Domains addressing social life and psychosocial functioning showed long-term increases in public interest. Renovation was the only domain to show a decrease in search interest with the onset of the lockdown. As changes in search behavior are consistent over multiple domains, a Google Trends analysis may provide information for policy makers on how to adapt and develop intervention, information, and prevention strategies, especially when NPIs are in effect.

Decomposing alpha and 1/f brain activities reveals their differential associations with cognitive processing speed.

Research in cognitive neuroscience has extensively demonstrated that the temporal dynamics of brain activity are associated with cognitive functioning. The temporal dynamics mainly include oscillatory and 1/f noise-like, non-oscillatory brain activities that coexist in many forms of brain activity and confound each other's variability. As such, observed functional associations of narrowband oscillations might have been confounded with the broadband 1/f component. Here, we investigated the relationship between resting-state EEG activity and the efficiency of cognitive functioning in N = 180 individuals. We show that 1/f brain activity plays an essential role in accounting for between-person variability in cognitive speed - a relationship that can be mistaken as originating from brain oscillations using conventional power spectrum analysis. At first glance, the power of alpha oscillations appeared to be predictive of cognitive speed. However, when dissociating pure alpha oscillations from 1/f brain activity, only the 1/f predicted cognitive speed, whereas the predictive power of alpha vanished. With this highly powered study, we disambiguate the functional relevance of the 1/f power law pattern in resting state neural activities and substantiate the necessity of isolating the 1/f component from oscillatory activities when studying the functional relevance of spontaneous brain activities.

Efficacy of psychotherapies and pharmacotherapies for Bulimia nervosa.

BACKGROUND: Bulimia nervosa (BN), a mental disorder that causes significant impairment, can be treated with psychological, pharmacological, nutrition-based and self-help interventions. We conducted a pre-registered meta-analysis of randomized-controlled trials (RCTs) to assess the efficacy of these interventions in up to 19 different interventions. METHODS: Database search terms were combined for BN and RCTs from database inception to March 2017. Abstinence from binge eating episodes, compensatory behaviors, the absence of a BN diagnosis and reduction of symptom severity were considered as primary outcome variables, reduction of self-reported eating pathology and depression served as secondary outcome variables. Retrieved RCTs were meta-analyzed using fixed and random effects models. RESULTS: RCT (79 trials; 5775 participants) effects post-treatment revealed moderate to large intervention effects for psychotherapy [mostly cognitive-behavioral therapy (CBT)] for primary outcome variables. Slightly reduced effects were obtained for self-help and moderate effects for pharmacotherapy. Similarly, psychotherapy yielded large to very large effects in regard to secondary outcome variables, while moderate to large effects were observed for self-help, Pharmacotherapy and combined therapies. Meta-analyses for the pre to post changes within group confirmed these findings. Additionally, follow-up analyses revealed the sustainability of psychotherapies in terms of large effects in primary outcome criteria, while these effects were moderate for self-help, pharmacotherapy, and combined therapies. CONCLUSIONS: Most psychological and pharmacological interventions revealed to be effective in BN treatment. Taking effect size, sustainability of the intervention, as well as the consistency of findings and available evidence into consideration, CBT can be recommended as the best intervention for the initial treatment of BN.

Utility of the PHQ-9 to identify major depressive disorder in adult patients in Spanish primary care centres.

BACKGROUND: The prevalence of major depressive disorder (MDD) in Spanish primary care (PC) centres is high. However, MDD is frequently underdiagnosed and consequently only some patients receive the appropriate treatment. The present study aims to determine the utility of the Patient Health Questionnaire-9 (PHQ-9) to identify MDD in a subset of PC patients participating in the large PsicAP study. METHODS: A total of 178 patients completed the full PHQ test, including the depression module (PHQ-9). Also, a Spanish version of the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) was implemented by clinical psychologists that were blinded to the PHQ-9 results. We evaluated the psychometric properties of the PHQ-9 as a screening tool as compared to the SCID-I as a reference standard. RESULTS: The psychometric properties of the PHQ-9 for a cut-off value of 10 points were as follows: sensitivity, 0.95; specificity, 0.67. Using a cut-off of 12 points, the values were: sensitivity, 0.84; specificity, 0.78. Finally, using the diagnostic algorithm for depression (DSM-IV criteria), the sensitivity was 0.88 and the specificity 0.80. CONCLUSIONS: As a screening instrument, the PHQ-9 performed better with a cut-off value of 12 versus the standard cut-off of 10. However, the best psychometric properties were obtained with the DSM-IV diagnostic algorithm for depression. These findings indicate that the PHQ-9 is a highly satisfactory tool that can be used for screening MDD in the PC setting. TRIAL REGISTRATION: Current Controlled Trials ISRCTN58437086 . Registered 20 May 2013.

Gating of attention towards food stimuli in binge eating disorder.

Cognitive models of eating disorders propose that attentional biases for disorder-relevant stimuli contribute to eating disorder pathology. Empirical evidence of a contribution of attentional biases for binge eating disorder (BED) is still scarce. The aim of the present study was to assess attention engagement towards, and disengagement from, food stimuli in overweight females with BED (n = 25) and a group of overweight and obese women without BED (OW; n = 30). Participants completed a rapid serial visual presentation (RSVP) paradigm with food and neutral words as target stimuli. This task can be used to decompose an attentional bias for food stimuli into its stimulus engagement and stimulus disengagement components. Findings indicate that facilitated stimulus engagement for food stimuli over neutral stimuli was more pronounced in the BED group compared to the OW group. Conversely, there were no substantial disengagement effects in either group. Thereby, results support the idea that early attentional processes are biased in BED.

Age-related increases in Stroop interference: delineation of general slowing based on behavioral and white matter analyses.

The Stroop interference task is a widely used paradigm to examine cognitive inhibition, which is a key component of goal-directed behavior. With increasing age, reaction times in the Stroop interference task are usually slowed. However, to date it is still under debate if age-related increases in reaction times are merely an artifact of general slowing. The current study was conducted to investigate the role of general slowing, as measured by Trail-Making-Test-A, in age-related alterations of Stroop interference. We applied Diffusion Tensor Imaging (DTI) to determine the topography of neuronal networks underlying Stroop interference under control of general slowing. On the behavioral level, linear regression analysis demonstrated that age accounted for significant variance on Stroop interference, whereas TMT-A performance did not. Controlling for TMT-A, DTI based white matter analyses demonstrated a strong association of Stroop interference with integrity measures of genu of corpus callosum, bilateral anterior corona radiata, and bilateral anterior limb of capsula interna. These pathways are associated with frontal brain regions by either connecting the bilateral dorsolateral prefrontal cortex or the anterior cingulate cortex with frontal and subcortical regions or by containing fibers which are part of cortico-thalamic circuits that cross prefrontal regions. Importantly, results expand our knowledge of the neural basis of Stroop interference and emphasize the importance of white matter integrity of frontal pathways in the modulation of Stroop interference. Combining behavioral and DTI findings our results further suggest that cognitive inhibition, as measured by Stroop task, is a qualitatively distinct cognitive process that declines with age.

General and food-specific inhibitory deficits in binge eating disorder.

OBJECTIVE: To investigate behavioral inhibition in individuals with binge eating disorder (BED) compared with overweight and obese individuals without BED (No-BED). METHOD: Participants with BED (n = 31) and the weight-matched No-BED group (n = 29) completed an inhibitory control task (stop-signal task, SST) with food and neutral stimuli. RESULTS: The BED group needed more time to stop an ongoing response, as indicated by increased stop signal reaction time (SSRT) relative to the No-BED group. Additionally, compared with the No-BED group, the BED group displayed more difficulty inhibiting responses elicited by food stimuli. The deficits in behavioral response inhibition were also found to be related to the severity of reported symptoms. DISCUSSION: There is a general deficit in late stage behavioral inhibition in BED, and this may be particularly pronounced in the context of food stimuli.

Attentional bias for food cues in binge eating disorder.

The aim of the present study was to investigate an attentional bias toward food stimuli in binge eating disorder (BED). To this end, a BED and a weight-matched control group (CG) completed a clarification task and a spatial cueing paradigm. The clarification task revealed that food stimuli were faster detected than neutral stimuli, and that this difference was more pronounced in BED than in the CG. The spatial cueing paradigm indicated a stimulus engagement effect in the BED group but not in the CG, suggesting that an early locus in stimulus processing contributes to differences between BED patients and obese controls. Both groups experienced difficulty disengaging attention from food stimuli, and this effect was only descriptively larger in the BED group. The effects obtained in both paradigms were found to be correlated with reported severity of BED symptoms. Of note, this relationship was partially mediated by the arousal associated with food stimuli relative to neutral stimuli, as predicted by an account on incentive sensitization.

Cognitive interference and a food-related memory bias in binge eating disorder.

The present study was concerned with cognitive interference and a specific memory bias for eating-related stimuli in binge eating disorder (BED). Further objectives were to find out under which circumstances such effects would occur, and whether they are related with each other and with reported severity of BED symptoms. A group of women diagnosed with BED and a matched sample of overweight controls completed two paradigms, an n-back task with lures and a recent-probes task. The BED group generally experienced more interference in the n-back task. Additionally, they revealed selectively increased interference for food items in the recent-probes task. Findings can be reconciled with the view that control functions are generally impaired in BED, and that there is an additional bias for eating-related stimuli, both of which were related with reported severity of BED symptoms.

Task Switching: On the Relation of Cognitive Flexibility with Cognitive Capacity.

The task-switching paradigm is deemed a measure of cognitive flexibility. Previous research has demonstrated that individual differences in task-switch costs are moderately inversely related to cognitive ability. However, current theories emphasize multiple component processes of task switching, such as task-set preparation and task-set inertia. The relations of task-switching processes with cognitive ability were investigated in the current study. Participants completed a task-switching paradigm with geometric forms and a visuospatial working memory capacity (WMC) task. The task-switch effect was decomposed with the diffusion model. Effects of task-switching and response congruency were estimated as latent differences using structural equation modeling. Their magnitudes and relations with visuospatial WMC were investigated. Effects in the means of parameter estimates replicated previous findings, namely increased non-decision time in task-switch trials. Further, task switches and response incongruency had independent effects on drift rates, reflecting their differential effects on task readiness. Findings obtained with the figural tasks employed in this study revealed that WMC was inversely related to the task-switch effect in non-decision time. Relations with drift rates were inconsistent. Finally, WMC was moderately inversely related to response caution. These findings suggest that more able participants either needed less time for task-set preparation or that they invested less time for task-set preparation.

Testing Replicability and Generalizability of the Time on Task Effect.

The time on task (ToT) effect describes the relationship of the time spent on a cognitive task and the probability of successful task completion. The effect has been shown to vary in size and direction across tests and even within tests, depending on the test taker and item characteristics. Specifically, investing more time has a positive effect on response accuracy for difficult items and low ability test-takers, but a negative effect for easy items and high ability test-takers. The present study sought to test the replicability of this result pattern of the ToT effect across samples independently drawn from the same populations of persons and items. Furthermore, its generalizability was tested in terms of differential correlations across ability tests. To this end, ToT effects were estimated for three different reasoning tests and one test measuring natural sciences knowledge in 10 comparable subsamples with a total N = 2640. Results for the subsamples were highly similar, demonstrating that ToT effects are estimated with sufficient reliability. Generally, faster answers tended to be more accurate, suggesting a relatively effortless processing style. However, with increasing item difficulty and decreasing person ability, the effect flipped to the opposite direction, i.e., higher accuracy with longer processing times. The within-task moderation of the ToT effect can be reconciled with an account on effortful processing or cognitive load. By contrast, the generalizability of the ToT effect across different tests was only moderate. Cross-test relations were stronger in relative terms if performance in the respective tasks was more strongly related. This suggests that individual differences in the ToT effect depend on test characteristics such as their reliabilities but also similarities and differences of their processing requirements.

High-resolution structure of a fish aquaporin reveals a novel extracellular fold.

Aquaporins are protein channels embedded in the lipid bilayer in cells from all organisms on earth that are crucial for water homeostasis. In fish, aquaporins are believed to be important for osmoregulation; however, the molecular mechanism behind this is poorly understood. Here, we present the first structural and functional characterization of a fish aquaporin; cpAQP1aa from the fresh water fish climbing perch (<i>Anabas testudineus</i>), a species that is of high osmoregulatory interest because of its ability to spend time in seawater and on land. These studies show that cpAQP1aa is a water-specific aquaporin with a unique fold on the extracellular side that results in a constriction region. Functional analysis combined with molecular dynamic simulations suggests that phosphorylation at two sites causes structural perturbations in this region that may have implications for channel gating from the extracellular side.

A bimolecular fluorescence complementation flow cytometry screen for membrane protein interactions.

Interactions between membrane proteins within a cellular environment are crucial for all living cells. Robust methods to screen and analyse membrane protein complexes are essential to shed light on the molecular mechanism of membrane protein interactions. Most methods for detecting protein:protein interactions (PPIs) have been developed to target the interactions of soluble proteins. Bimolecular fluorescence complementation (BiFC) assays allow the formation of complexes involving PPI partners to be visualized in vivo, irrespective of whether or not these interactions are between soluble or membrane proteins. In this study, we report the development of a screening approach which utilizes BiFC and applies flow cytometry to characterize membrane protein interaction partners in the host Saccharomyces cerevisiae. These data allow constructive complexes to be discriminated with statistical confidence from random interactions and potentially allows an efficient screen for PPIs in vivo within a high-throughput setup.

Binding Costs in Processing Efficiency as Determinants of Cognitive Ability.

Performance in elementary cognitive tasks is moderately correlated with fluid intelligence and working memory capacity. These correlations are higher for more complex tasks, presumably due to increased demands on working memory capacity. In accordance with the binding hypothesis, which states that working memory capacity reflects the limit of a person's ability to establish and maintain temporary bindings (e.g., relations between items or relations between items and their context), we manipulated binding requirements (i.e., 2, 4, and 6 relations) in three choice reaction time paradigms (i.e., two comparison tasks, two change detection tasks, and two substitution tasks) measuring mental speed. Response time distributions of 115 participants were analyzed with the diffusion model. Higher binding requirements resulted in generally reduced efficiency of information processing, as indicated by lower drift rates. Additionally, we fitted bi-factor confirmatory factor analysis to the elementary cognitive tasks to separate basal speed and binding requirements of the employed tasks to quantify their specific contributions to working memory capacity, as measured by Recall-1-Back tasks. A latent factor capturing individual differences in binding was incrementally predictive of working memory capacity, over and above a general factor capturing speed. These results indicate that the relation between reaction time tasks and working memory capacity hinges on the complexity of the reaction time tasks. We conclude that binding requirements and, therefore, demands on working memory capacity offer a satisfactory account of task complexity that accounts for a large portion of individual differences in ability.

Emotional Disorders During the COVID-19 Outbreak in Spain: The Role of Sociodemographic Risk Factors and Cognitive Emotion Regulation Strategies.

BACKGROUND: Cognitive emotion regulation strategies (CERS) play a transdiagnostic role in emotional disorders, but the role of these strategies in coping with emotions during the coronavirus disease 2019 (COVID-19) pandemic remains poorly understood. AIMS: To assess the presence of emotional disorders in Spain and the association to sociodemographic characteristics and CERS during the COVID-19 outbreak. METHOD: Cross-sectional survey administered through an online platform. Sociodemographic variables and CERS (CERQ-Short) were collected and possible diagnoses of generalized anxiety disorder (GAD, GAD-7), major depression disorder (MDD; Patient Health Questionnaire-9 [PHQ-9]), panic attacks (PA; PHQ-PD), and panic disorders (PD; PHQ-PD) were assessed. Sociodemographic risk factors and CERS association to the possible diagnosis of emotional disorders were reported with hierarchical multivariate logistic regression analyses. RESULTS: A total of 1,753 respondents completed the questionnaire in Spain. Of these, most (76.8%) were female, with a mean (SD) age of 40.4 years (12.9). A high proportion of participants met diagnostic criteria for emotional disorders: 15.3% for GAD, 12.2% for MDD, 17.2% for PD, and 25.7% had experienced a PA. The contribution of sociodemographic variables to diagnoses of emotional disorders was modest, explaining from 3.1% to 5.7% of the variance; however, when CERS were added, the combination of sociodemographic and CERS explained from 15% to 29% of the variance. Rumination and catastrophizing were the most transdiagnostic maladaptive strategies and positive refocusing was another adaptive strategy. DISCUSSION: Although results from convenience samples should be handled with caution, the high prevalence of emotional disorders in this study suggests that the demand of mental health interventions will probably increase in Spain. Also, CERS play a clear role in the presence of these disorders. CONCLUSION: Intervention programs should focus on training CERS in populations at high risk, focusing on the reduction of maladaptive CERS and the reinforce of other more adaptive CERS.

Predicting suicidal behavior by implicit associations with death? Examination of the death IAT in two inpatient samples of differing suicide risk.

Assessment of implicit self-associations with death, measured by a death Implicit Association Test (IAT), has shown promise for the prediction of suicide risk. The present study examined whether the performance on the death IAT is associated with lifetime, recent, or future suicide attempt status as well as self-report measures of suicide risk factors (e.g., perceived burdensomeness, thwarted belongingness) in two inpatient samples with low versus high severity of suicidality. Furthermore, we investigated whether explicit suicidal ideation and implicit associations with death predict recent and future suicide attempt status. Seventy-one depressed inpatients with recent/lifetime suicidal ideation (first sample) as well as 226 inpatients with a recent suicide attempt or a severe suicidal crisis (second sample) were interviewed on lifetime suicidal ideation and behavior, completed self-report measures (i.e., suicidal ideation, thwarted belongingness, perceived burdensomeness), and conducted the death IAT. The second sample was also interviewed and completed self-report measures longitudinally, 6, 9, and 12 months later. The IAT was conducted twice in this sample, at the beginning of the assessment (T0) as well as 12 months later (T3). Implicit associations with death neither differ between lifetime suicide ideators, single attempters, and multiple attempters, nor between recent and future nonattempters and attempters. IAT scores were unrelated to other suicide risk factors. Neither the IAT scores nor the interaction of IAT scores and explicitly stated suicidal ideation was predictive of recent or future suicide attempts. The present study points to a limited utility of the death IAT for the prediction of suicide risk. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Molecular Level Characterization of Circulating Aquaporin-4 Antibodies in Neuromyelitis Optica Spectrum Disorder.

OBJECTIVE: To determine whether distinct aquaporin-4 (AQP4)-IgG lineages play a role in neuromyelitis optica spectrum disorder (NMOSD) pathogenesis, we profiled the AQP4-IgG polyclonal serum repertoire and identified, quantified, and functionally characterized distinct AQP4-IgG lineages circulating in 2 patients with NMOSD. METHODS: We combined high-throughput sequencing and quantitative immunoproteomics to simultaneously determine the constituents of both the B-cell receptor (BCR) and the serologic (IgG) anti-AQP4 antibody repertoires in the peripheral blood of patients with NMOSD. The monoclonal antibodies identified by this platform were recombinantly expressed and functionally characterized in vitro. RESULTS: Multiple antibody lineages comprise serum AQP4-IgG repertoires. Their distribution, however, can be strikingly different in polarization (polyclonal vs pauciclonal). Among the 4 serum AQP4-IgG monoclonal antibodies we identified in 2 patients, 3 induced complement-dependent cytotoxicity in a model mammalian cell line (p < 0.01). CONCLUSIONS: The composition and polarization of AQP4-IgG antibody repertoires may play an important role in NMOSD pathogenesis and clinical presentation. Here, we present a means of coupling both cellular (BCR) and serologic (IgG) antibody repertoire analysis, which has not previously been performed in NMOSD. Our analysis could be applied in the future to clinical management of patients with NMOSD to monitor disease activity over time as well as applied to other autoimmune diseases to facilitate a deeper understanding of disease pathogenesis relative to autoantibody clones.

Patient participation in antipsychotic drug choice decisions.

Patient inclusion in antipsychotic drug decisions is recommended by international treatment guidelines. For N=300 in patients with schizophrenia, we analysed patients' preferences for inclusion in decisions and physicians' estimates which patients actually participated in drug choice. Path analysis was used to examine the relationships between patients' preferences/actual participation and clinical variables measured. Forty percent of the patients expressed a wish to participate in clinical decisions. Those patients wishing to participate in medical decisions had less insight into the necessity of treatment. Psychiatrists gave better ratings of the doctor-patient relationship to those patients whom they rated as having participated in their drug choice. These patients had more positive attitudes towards antipsychotic medication. There was no relationship between the desire to participate and actual participation in the drug choice. When working with patients exhibiting poor insight and negative drug attitudes, psychiatrists use authoritative decision-making styles despite the patient's desire to participate.

Quantitative analysis of H2O2 transport through purified membrane proteins.

Hydrogen peroxide (H2O2) is an important signal molecule produced in animal and plant cells. The balance of H2O2 between the intra- and extracellular space is regulated by integral membrane proteins, which thereby modulate signaling. Several methods have been established to analyze aquaporin mediated transport of H2O2 in whole cells with the intrinsic limitation that the amount of protein responsible for a certain activity cannot be standardized. As a consequence, the quantification of the transport and specific activity is difficult to extract making it problematic to compare isoforms and mutated variants of one specific target. Moreover, in cell-based assays, the expression of the target protein may alter the physiological processes of the host cell providing a complication and the risk of misleading results. To improve the measurements of protein based H2O2 transport, we have developed an assay allowing quantitative measurements.•Using purified aquaporin reconstituted in proteoliposomes, transport of H2O2 can be accurately measured.•Inside the liposomes, H2O2 catalyzes the reaction between Amplex Red and horseradish peroxidase (HRP) giving rise to the fluorescent product resorufin.•Analysing pure protein provides direct biochemical evidence of a specific transport excluding putative cellular background.

Characterization of aquaporin-driven hydrogen peroxide transport.

Aquaporins are membrane-intrinsic proteins initially defined as water (H2O) channels in all organisms and subsequently found to have multiple substrate specificities, such as hydrogen peroxide (H2O2). H2O2 is a signaling molecule that partakes in immune responses where its transport is mediated by aquaporins. To shed further light on the molecular basis of the aquaporin function in H2O2 transport, we have characterized an Arabidopsis thaliana aquaporin, AtPIP2;4, recombinantly produced to high yields in Pichia pastoris. Here, we present a newly established assay that allows detection of H2O2 transport by purified aquaporins reconstituted into liposomes, enabling us to compare aquaporin homologues with respect to substrate specificity. To get additional insight into the structural determinants for aquaporin-mediated H2O2 transport, we solved the 3D-structure of AtPIP2;4 to 3.7 Šresolution and found structural identity to the water channel from spinach (SoPIP2;1), with the difference that Cd2+ cation is not required to retain the closed conformation. The transport specificities of the two plant aquaporins were compared to a human homologue, AQP1. Overall, we conclude that AtPIP2;4, SoPIP2;1 and hAQP1 are all transporters of both H2O and H2O2, but have different efficiencies for various specificities. Notably, all three homologues expedite H2O transport equally well while the plant aquaporins are more permeable to H2O2 than hAQP1. Comparison of the structures indicates that the observed variations in H2O and H2O2 transport cannot be explained by differences in the monomeric pore. Possibly, the determinants for transport specificities reside in the flexible domains outside the membrane core of these channels.