A new lysine biosynthetic enzyme from a bacterial endosymbiont shaped by genetic drift and genome reduction.

The effect of population bottlenecks and genome reduction on enzyme function is poorly understood. Candidatus Liberibacter solanacearum is a bacterium with a reduced genome that is transmitted vertically to the egg of an infected psyllid-a population bottleneck that imposes genetic drift and is predicted to affect protein structure and function. Here, we define the function of Ca. L. solanacearum dihydrodipicolinate synthase (CLsoDHDPS), which catalyzes the committed branchpoint reaction in diaminopimelate and lysine biosynthesis. We demonstrate that CLsoDHDPS is expressed in Ca. L. solanacearum and expression is increased ~2-fold in the insect host compared to in planta. CLsoDHDPS has decreased thermal stability and increased aggregation propensity, implying mutations have destabilized the enzyme but are compensated for through elevated chaperone expression and a stabilized oligomeric state. CLsoDHDPS uses a ternary-complex kinetic mechanism, which is to date unique among DHDPS enzymes, has unusually low catalytic ability, but an unusually high substrate affinity. Structural studies demonstrate that the active site is more open, and the structure of CLsoDHDPS with both pyruvate and the substrate analogue succinic-semialdehyde reveals that the product is both structurally and energetically different and therefore evolution has in this case fashioned a new enzyme. Our study suggests the effects of genome reduction and genetic drift on the function of essential enzymes and provides insights on bacteria-host co-evolutionary associations. We propose that bacteria with endosymbiotic lifestyles present a rich vein of interesting enzymes useful for understanding enzyme function and/or informing protein engineering efforts.

A Direct Comparison, and Prioritisation, of the Immunotherapeutic Targets Expressed by Adult and Paediatric Acute Myeloid Leukaemia Cells: A Systematic Review and Meta-Analysis.

Acute myeloid leukaemia (AML) is characterized by impaired myeloid differentiation resulting in an accumulation of immature blasts in the bone marrow and peripheral blood. Although AML can occur at any age, the incidence peaks at age 65. The pathobiology of AML also varies with age with associated differences in incidence, as well as the frequency of cytogenetic change and somatic mutations. In addition, 5-year survival rates in paediatrics are 60-75% but fall to 5-15% in older AML patients. This systematic review aimed to determine whether the altered genes in AML affect the same molecular pathways, indifferent of patient age, and, therefore, whether patients could benefit from the repurposing drugs or the use of the same immunotherapeutic strategies across age boundaries to prevent relapse. Using a PICO framework and PRISMA-P checklist, relevant publications were identified using five literature databases and assessed against an inclusion criteria, leaving 36 articles, and 71 targets for therapy, for further analysis. QUADAS-2 was used to determine the risk of bias and perform a quality control step. We then priority-ranked the list of cancer antigens based on predefined and pre-weighted objective criteria as part of an analytical hierarchy process used for dealing with complex decisions. This organized the antigens according to their potential to act as targets for the immunotherapy of AML, a treatment that offers an opportunity to remove residual leukaemia cells at first remission and improve survival rates. It was found that 80% of the top 20 antigens identified in paediatric AML were also within the 20 highest scoring immunotherapy targets in adult AML. To analyse the relationships between the targets and their link to different molecular pathways, PANTHER and STRING analyses were performed on the 20 highest scoring immunotherapy targets for both adult and paediatric AML. There were many similarities in the PANTHER and STRING results, including the most prominent pathways being angiogenesis and inflammation mediated by chemokine and cytokine signalling pathways. The coincidence of targets suggests that the repurposing of immunotherapy drugs across age boundaries could benefit AML patients, especially when used in combination with conventional therapies. However, due to cost implications, we would recommend that efforts are focused on ways to target the highest scoring antigens, such as WT1, NRAS, IDH1 and TP53, although in the future other candidates may prove successful.

Oxidation of caspase-8 by hypothiocyanous acid enables TNF-mediated necroptosis.

Necroptosis is a form of regulated cell death triggered by various host and pathogen-derived molecules during infection and inflammation. The essential step leading to necroptosis is phosphorylation of the mixed lineage kinase domain-like protein by receptor-interacting protein kinase 3. Caspase-8 cleaves receptor-interacting protein kinases to block necroptosis, so synthetic caspase inhibitors are required to study this process in experimental models. However, it is unclear how caspase-8 activity is regulated in a physiological setting. The active site cysteine of caspases is sensitive to oxidative inactivation, so we hypothesized that oxidants generated at sites of inflammation can inhibit caspase-8 and promote necroptosis. Here, we discovered that hypothiocyanous acid (HOSCN), an oxidant generated in vivo by heme peroxidases including myeloperoxidase and lactoperoxidase, is a potent caspase-8 inhibitor. We found HOSCN was able to promote necroptosis in mouse fibroblasts treated with tumor necrosis factor. We also demonstrate purified caspase-8 was inactivated by low concentrations of HOSCN, with the predominant product being a disulfide-linked dimer between Cys360 and Cys409 of the large and small catalytic subunits. We show oxidation still occurred in the presence of reducing agents, and reduction of the dimer was slow, consistent with HOSCN being a powerful physiological caspase inhibitor. While the initial oxidation product is a dimer, further modification also occurred in cells treated with HOSCN, leading to higher molecular weight caspase-8 species. Taken together, these findings indicate major disruption of caspase-8 function and suggest a novel mechanism for the promotion of necroptosis at sites of inflammation.

Coping and Conformity Motives Mediate the Joint Effects of the Behavioral Inhibition and Approach Systems on Alcohol Problems in Young Adults.

Background: Gray's original Reinforcement Sensitivity Theory (RST) posits that an oversensitive behavioral inhibition system (BIS) may increase risk for negative-reinforcement-motivated drinking, given its role in anxiety. However, existing data provides mixed support for the BIS-alcohol use association. The inconsistent evidence is not surprising, as the revised RST predicts that the behavioral approach system (BAS) should moderate the effect of the BIS on alcohol use. A strong BAS is thought to bring attention to the negatively reinforcing effects of alcohol, leading to problem drinking among those with a strong BIS. While emerging results support this interaction, we still have much to learn about the mechanisms underlying this effect on alcohol use. Accordingly, we examined motives for alcohol use as mediators of the joint associations of the BIS and the BAS on drinking behaviors. Specifically, our central hypothesis was that individuals with a strong BIS and a strong BAS would endorse increased negative reinforcement motives for drinking (coping and conformity motives), which in turn would predict heavy drinking and alcohol problems. Method: Participants (N=346; 195 women) completed study measures as part of the baseline assessment for a larger study. Results: Overall, results partially supported the hypotheses. Mediated moderation analyses showed that the indirect effect of the BIS on alcohol problems, through coping and conformity motives, was strongest at high levels of the BAS. This effect was not supported for alcohol use. Conclusions: Our findings suggest that clinical interventions should target coping and conformity reasons for drinking among anxious, reward responsive, young adults.

Efficacy of a novel online integrated treatment for problem gambling and tobacco smoking: Results of a randomized controlled trial.

Background and aims: Problem gambling and tobacco use are highly comorbid among adults. However, there are few treatment frameworks that target both gambling and tobacco use simultaneously (i.e., an integrated approach), while also being accessible and evidence-based. The aim of this two-arm open label RCT was to examine the efficacy of an integrated online treatment for problem gambling and tobacco use. Methods: A sample of 209 participants (Mage = 37.66, SD = 13.81; 62.2% female) from North America were randomized into one of two treatment conditions (integrated [n = 91] or gambling only [n = 118]) that lasted for eight weeks and consisted of seven online modules. Participants completed assessments at baseline, after treatment completion, and at 24-week follow-up. Results: While a priori planned generalized linear mixed models showed no condition differences on primary (gambling days, money spent, time spent) and secondary outcomes, both conditions did appear to significantly reduce problem gambling and smoking behaviours over time. Post hoc analyses showed that reductions in smoking and gambling craving were correlated with reductions in days spent gambling, as well as with gambling disorder symptoms. Relatively high (versus low) nicotine replacement therapy use was associated with greater reductions in gambling behaviours in the integrated treatment condition. Discussion and conclusions: While our open label RCT does not support a clear benefit of integrated treatment, findings suggest that changes in smoking and gambling were correlated over time, regardless of treatment condition, suggesting that more research on mechanisms of smoking outcomes in the context of gambling treatment may be relevant.

Fast-track pathway for early diagnosis and management of giant cell arteritis: the combined role of vascular ultrasonography and [18F]-fluorodeoxyglucose PET-computed tomography imaging.

Giant cell arteritis (GCA) is a medical emergency, which can lead to irreversible blindness and other ischaemic vascular events if left untreated. Prompt access to specialist assessment, diagnostics in the form of a fast-track pathway (FTP) and access to appropriate treatment are key factors in preventing morbidity associated with this disease. Recent developments in vascular imaging prompted review of our management of GCA patients. Here, we present the newly implemented FTP in GCA at the University College London Hospital, with added vascular imaging in the form of temporal artery ultrasound (TAUS) and [18F]-fluorodeoxyglucose PET-computed tomography ( 18 F-FDG PET-CT) with temporal artery biopsy. The initial pilot data on the FTP showed a significant negative predictive value of the combined TAUS and 18 F-FDG PET-CT, and the vast majority of cases positive on imaging were confirmed by biopsy. Through the new FTP in GCA, the diagnosis was completed within 48-72 h, compared with the conventional pathway time of up to 2-3 weeks awaiting biopsy results. Prompt and accurate diagnosis of GCA enables commencement of corticosteroid (prednisolone) treatment in the appropriate patient population while avoiding unnecessary steroid exposure and toxicity in GCA-negative patients.

Hazardous Drinking Mediates the Relation Between Externalizing Personality and Reduced Adherence to COVID-19 Public Health Guidelines in University Students.

Using a multigroup path analysis, we examined if hazardous alcohol use mediated the relations between elevated externalizing personality traits (i.e., impulsivity or sensation seeking) and reduced adherence to COVID-19 public health guidelines. We hypothesized that those high in externalizing personality traits would demonstrate less adherence to public health guidelines and that hazardous alcohol use would mediate this relationship. First- and second-year undergraduates (N = 1232; ages 18-25) from five Canadian universities participated in a cross-sectional survey between January to April 2021. Individuals with higher levels of impulsive or sensation seeking personality traits demonstrated poorer adherence to COVID-19 public health guidelines and these relations were mediated by hazardous alcohol use. Results suggest that hazardous drinking is an important target for students high in impulsivity and sensation seeking to increase their adherence to public health guidelines and thereby help control viral spread.

Intracortical myelin in individuals with alcohol use disorder: An initial proof-of-concept study.

INTRODUCTION: Disruption of cortical gray matter and white matter tracts are well-established markers of alcohol use disorder (AUD), but less is known about whether similar differences are present in intracortical myelin (ICM, i.e., highly myelinated gray matter in deeper cortical layers). The goal of this study was to provide initial proof-of-concept for using an optimized structural magnetic resonance imaging (MRI) sequence to detect differences in ICM in individuals with AUD compared to control participants reporting drinking within recommended guidelines. METHODS: This study used an optimized 3T MRI sequence for high intracortical contrast to examine ICM-related MRI signal in 30 individuals with AUD and 33 healthy social drinkers. Surface-based analytic techniques were used to quantify ICM-related MRI signal in 20 bilateral a priori regions of interest based on prior cortical thickness studies, and exploratory vertex-wise analyses were examined using Cohen's d effect size. RESULTS: The global distribution of ICM-related signal was largely comparable between groups. Region of interest analysis indicated that AUD group exhibited greater ICM-related MRI signal in precuneus, ventromedial prefrontal cortex, posterior cingulate, middle anterior cingulate, middle/posterior insula, and dorsolateral prefrontal cortex (Cohen's ds = 0.50-0.75). Four regions (right precuneus, ventromedial prefrontal cortex, posterior cingulate and left dorsolateral prefrontal cortex) remained significant (p < .05) after covarying for smoking status. CONCLUSION: These findings provide initial evidence of ICM differences in a moderately sized sample of individuals with AUD compared to controls, although the inflation of type 1 error rate necessitates caution in drawing conclusions. Robustly establishing these differences in larger samples is necessary. The cross-sectional design cannot address whether the observed differences predate AUD or are consequences of heavy alcohol consumption.

Fermentation of plant-based dairy alternatives by lactic acid bacteria.

Ethical, environmental and health concerns around dairy products are driving a fast-growing industry for plant-based dairy alternatives, but undesirable flavours and textures in available products are limiting their uptake into the mainstream. The molecular processes initiated during fermentation by lactic acid bacteria in dairy products is well understood, such as proteolysis of caseins into peptides and amino acids, and the utilisation of carbohydrates to form lactic acid and exopolysaccharides. These processes are fundamental to developing the flavour and texture of fermented dairy products like cheese and yoghurt, yet how these processes work in plant-based alternatives is poorly understood. With this knowledge, bespoke fermentative processes could be engineered for specific food qualities in plant-based foods. This review will provide an overview of recent research that reveals how fermentation occurs in plant-based milk, with a focus on how differences in plant proteins and carbohydrate structure affect how they undergo the fermentation process. The practical aspects of how this knowledge has been used to develop plant-based cheeses and yoghurts is also discussed.

A longitudinal approach to understanding risk factors for problem alcohol use during the COVID-19 pandemic.

BACKGROUND: We conducted a longitudinal study to examine person-centered heterogeneity in problem drinking risk during the 2019 Coronavirus disease (COVID-19) pandemic. We aimed to differentiate high- from low-risk subgroups of drinkers during the pandemic, to report on the longitudinal follow-up of the baseline sample reported in Wardell et al. (Alcohol Clin Exp Res, 44, 2020, 2073), and to examine how subgroups of drinkers differed on coping-related and pre-pandemic alcohol vulnerability factors. METHODS: Canadian alcohol users (N = 364) were recruited for the study. Participants completed surveys at four waves (spaced 3 months apart), with the first being 7 to 8 weeks after the COVID-19 state of emergency began in Canada. The data were analyzed using a parallel process latent growth class analysis followed by general linear mixed models analysis. RESULTS: We found evidence for three latent classes: individuals who increased drinking (class 1; n = 23), low-risk drinkers (class 2; n = 311), and individuals who decreased drinking (class 3; n = 30). Participants who increased (vs. those who decreased) problem drinking during the pandemic struggled with increasing levels of social disconnection and were also increasingly more likely to report drinking to cope with these issues. Those in the increasing class (relative to low-risk drinkers) reported increasing levels of depression during the study. Relative to low-risk drinkers, participants in the increasing class had higher pre-pandemic AUDIT scores, greater frequency of solitary drinking, and higher alcohol demand. Interestingly, participants in the decreasing class had the highest pre-pandemic AUDIT scores. CONCLUSIONS: We examined longitudinal data to identify subgroups of drinkers during the pandemic and to identify factors that may have contributed to increased problem drinking. Findings suggest that while most of the sample did not change their alcohol use, a small portion of individuals escalated use, while a small portion decreased their drinking. Identifying the vulnerability factors associated with increased drinking could aid in the development of preventative strategies and intervention approaches.

Neutrophil-vascular interactions drive myeloperoxidase accumulation in the brain in Alzheimer's disease.

INTRODUCTION: Neutrophil accumulation is a well-established feature of Alzheimer's disease (AD) and has been linked to cognitive impairment by modulating disease-relevant neuroinflammatory and vascular pathways. Neutrophils express high levels of the oxidant-generating enzyme myeloperoxidase (MPO), however there has been controversy regarding the cellular source and localisation of MPO in the AD brain. MATERIALS AND METHODS: We used immunostaining and immunoassays to quantify the accumulation of neutrophils in human AD tissue microarrays and in the brains of APP/PS1 mice. We also used multiplexed immunolabelling to define the presence of NETs in AD. RESULTS: There was an increase in neutrophils in AD brains as well as in the murine APP/PS1 model of AD. Indeed, MPO expression was almost exclusively confined to S100A8-positive neutrophils in both human AD and murine APP/PS1 brains. The vascular localisation of neutrophils in both human AD and mouse models of AD was striking and driven by enhanced neutrophil adhesion to small vessels. We also observed rare infiltrating neutrophils and deposits of MPO around plaques. Citrullinated histone H3, a marker of neutrophil extracellular traps (NETs), was also detected in human AD cases at these sites, indicating the presence of extracellular MPO in the vasculature. Finally, there was a reduction in the endothelial glycocalyx in AD that may be responsible for non-productive neutrophil adhesion to the vasculature. CONCLUSION: Our report indicates that vascular changes may drive neutrophil adhesion and NETosis, and that neutrophil-derived MPO may lead to vascular oxidative stress and be a relevant therapeutic target in AD.

Resting state functional connectivity in alcohol users and co-users of other substances.

Polysubstance use (PSU) is the use of more than one psychoactive substance simultaneously or independently, and occurs in roughly half of individuals who seek treatment for substance use. The current study sought to use resting state functional connectivity (rs-FC) to examine functional connectivity in participants who report using multiple or single substances. Participants were drawn from a larger neuroimaging study. From there, participants were placed into one of three groups based on their frequency of alcohol, tobacco, cannabis, and illicit drug use. The final sample consisted of 82 participants. We observed three clusters that differed significantly between the three groups; one within the salience network and two within the temporal network. Tri+ users were found to have a lesser amount of rs-FC in these regions (compared to the other two groups) and dual users were found to have a greater amount of rs-FC within these regions. Findings indicate that use of three or more substances may significantly impact rs-FC within the salience and temporal networks, and that those who use alcohol+cannabis have significantly greater rs-FC than those who use alcohol+tobacco. Research is needed to examine larger samples of PSU for comparisons across specific substance combinations.

Survivin' Acute Myeloid Leukaemia-A Personalised Target for inv(16) Patients.

Despite recent advances in therapies including immunotherapy, patients with acute myeloid leukaemia (AML) still experience relatively poor survival rates. The Inhibition of Apoptosis (IAP) family member, survivin, also known by its gene and protein name, Baculoviral IAP Repeat Containing 5 (BIRC5), remains one of the most frequently expressed antigens across AML subtypes. To better understand its potential to act as a target for immunotherapy and a biomarker for AML survival, we examined the protein and pathways that BIRC5 interacts with using the Kyoto Encyclopedia of Genes and Genomes (KEGG), search tool for recurring instances of neighbouring genes (STRING), WEB-based Gene Set Analysis Toolkit, Bloodspot and performed a comprehensive literature review. We then analysed data from gene expression studies. These included 312 AML samples in the Microarray Innovations In Leukemia (MILE) dataset. We found a trend between above median levels of BIRC5 being associated with improved overall survival (OS) but this did not reach statistical significance (p = 0.077, Log-Rank). There was some evidence of a beneficial effect in adjusted analyses where above median levels of BIRC5 were shown to be associated with improved OS (p = 0.001) including in Core Binding Factor (CBF) patients (p = 0.03). Above median levels of BIRC5 transcript were associated with improved relapse free survival (p < 0.0001). Utilisation of a second large cDNA microarray dataset including 306 AML cases, again showed no correlation between BIRC5 levels and OS, but high expression levels of BIRC5 correlated with worse survival in inv(16) patients (p = 0.077) which was highly significant when datasets A and B were combined (p = 0.001). In addition, decreased BIRC5 expression was associated with better clinical outcome (p = 0.004) in AML patients exhibiting CBF mainly due to patients with inv(16) (p = 0.007). This study has shown that BIRC5 expression plays a role in the survival of AML patients, this association is not apparent when we examine CBF patients as a cohort, but when those with inv(16) independently indicating that those patients with inv(16) would provide interesting candidates for immunotherapies that target BIRC5.

Is talk cheap? Correspondence between self-attributions about changes in drinking and longitudinal changes in drinking during the 2019 coronavirus pandemic.

BACKGROUND: There are concerns that the coronavirus disease 2019 (COVID-19) pandemic may increase drinking, but most accounts to date are cross-sectional studies of self-attributions about alcohol-related impacts and the accuracy of those perceptions has not been investigated. The current study examined the correspondence between self-attributions of pandemic-related changes in drinking and longitudinally-measured changes in drinking and alcohol-related consequences in a sample of emerging adults. METHODS: In an existing ongoing longitudinal study on alcohol misuse (≥1 heavy episodic drinking day/month) in emerging adults, 473 individuals (Mage  = 23.8; 41.7% male) received a supplemental assessment from June 17th to July 1st, 2020, during public health restrictions in Ontario, Canada. These intrapandemic data were matched to the most recent assessment prior to the pandemic (~8 months earlier). Self-attributions about changes in drinking were assessed globally (i.e., increases/decreases/no change) and with higher resolution questions clarifying the magnitude of changes. RESULTS: Global self-attributions about changes in drinking substantively paralleled longitudinal changes in weekly drinking days (DD). In the longitudinal data, individuals' who self-reported increases in drinking exhibited significant increases; individuals' who self-reported decreases exhibited significant decreases; and individuals who self-reported no change exhibited nonsignificant changes. Higher resolution items likewise revealed longitudinal patterns of weekly drinking that were substantively consistent with self-attributions. Heavy DD and alcohol-related consequences exhibited similar patterns, but only individuals who self-reported large increases in drinking exhibited increases on these outcomes. Individuals who reported large increases in drinking also exhibited significant increases in depression and posttraumatic stress disorder symptoms. CONCLUSIONS: Self-attributions about drinking closely corresponded to longitudinal changes in drinking, supporting the validity of self-attributions in population-level surveys, particularly in young adults. Notably, a subgroup was identified that exhibited pronounced increases for all alcohol-related outcomes and concurrent increases in internalizing psychopathology.

Impulsivity as a mediating factor in the association between posttraumatic stress disorder symptoms and substance use.

OBJECTIVE: Posttraumatic stress disorder (PTSD) has been associated with heightened impulsivity and risk-taking behaviors, including higher rates of substance use than individuals without PTSD. Although a number of studies suggest that impulsivity is associated with substance use in PTSD, the specific role of impulsivity in this common pattern of comorbidity remains unclear. The current study investigated associations between PTSD symptoms, substance use patterns, and impulsivity in a sample of adults. METHOD: A total of 2,967 participants were recruited online through Amazon's Mechanical Turk. Participants who did not report at least one Criterion A traumatic event on the Brief Trauma Questionnaire were excluded. The remaining 1,609 trauma-exposed individuals were placed into either the probable PTSD group (n = 406) or the trauma-exposed non-PTSD group (n = 1,203) based on their PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders, fifth edition (PCL-5) score. Impulsivity was assessed via a delay discounting measure and the brief UPPS-P (urgency, premeditation, perseverance, sensation seeking, and positive urgency) Impulsive Behavior Scale. Alcohol and cannabis were assessed using the Alcohol Use Disorders Identification Test (AUDIT) and Cannabis Use Disorders Identification Test (CUDIT-R) scales, respectively. RESULTS: Probable PTSD participants exhibited steeper (more impulsive) delay discounting and endorsed more impulsive traits than participants in the trauma-exposed non-PTSD group. Moreover, the PTSD group reported significantly higher scores on both the AUDIT and CUDIT-R. Lastly, impulsive personality traits on the UPPS-P partially mediated the association between PTSD and both cannabis and alcohol use. CONCLUSIONS: These findings suggest that trauma-exposed individuals who exhibit elevated PTSD symptoms show heightened impulsivity. It also appears that lower levels of impulsivity may serve as a protective factor among trauma-exposed individuals resilient to the development of PTSD. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Cysteine oxidation triggers amyloid fibril formation of the tumor suppressor p16INK4A.

The tumor suppressor p16INK4A induces cell cycle arrest and senescence in response to oncogenic transformation and is therefore frequently lost in cancer. p16INK4A is also known to accumulate under conditions of oxidative stress. Thus, we hypothesized it could potentially be regulated by reversible oxidation of cysteines (redox signaling). Here we report that oxidation of the single cysteine in p16INK4A in human cells occurs under relatively mild oxidizing conditions and leads to disulfide-dependent dimerization. p16INK4A is an all α-helical protein, but we find that upon cysteine-dependent dimerization, p16INK4A undergoes a dramatic structural rearrangement and forms aggregates that have the typical features of amyloid fibrils, including binding of diagnostic dyes, presence of cross-ß sheet structure, and typical dimensions found in electron microscopy. p16INK4A amyloid formation abolishes its function as a Cyclin Dependent Kinase 4/6 inhibitor. Collectively, these observations mechanistically link the cellular redox state to the inactivation of p16INK4A through the formation of amyloid fibrils.

Formation of Amphipathic Amyloid Monolayers from Fungal Hydrophobin Proteins.

The fungal hydrophobins are small proteins that are able to self-assemble spontaneously into amphipathic monolayers at hydrophobic:hydrophilic interfaces. These protein monolayers can reverse the wettability of a surface, making them suitable for increasing the biocompatibility of many hydrophobic nanomaterials. One subgroup of this family, the class I hydrophobins, forms monolayers that are composed of extremely robust amyloid-like fibrils, called rodlets. Here, we describe the protocols for the production and purification of recombinant hydrophobins and oxidative refolding to a biologically active, soluble, monomeric form. We describe methods to trigger the self-assembly into the fibrillar rodlet state and techniques to characterize the physicochemical properties of the polymeric forms.

Delay Discounting as a Transdiagnostic Process in Psychiatric Disorders: A Meta-analysis.

Importance: Delay discounting is a behavioral economic index of impulsive preferences for smaller-immediate or larger-delayed rewards that is argued to be a transdiagnostic process across health conditions. Studies suggest some psychiatric disorders are associated with differences in discounting compared with controls, but null findings have also been reported. Objective: To conduct a meta-analysis of the published literature on delay discounting in people with psychiatric disorders. Data Sources: PubMed, MEDLINE, PsycInfo, Embase, and Web of Science databases were searched through December 10, 2018. The psychiatric keywords used were based on DSM-IV or DSM-5 diagnostic categories. Collected data were analyzed from December 10, 2018, through June 1, 2019. Study Selection: Following a preregistered Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol, 2 independent raters reviewed titles, abstracts, and full-text articles. English-language articles comparing monetary delay discounting between participants with psychiatric disorders and controls were included. Data Extraction and Synthesis: Hedges g effect sizes were computed and random-effects models were used for all analyses. Heterogeneity statistics, one-study-removed analyses, and publication bias indices were also examined. Main Outcomes and Measures: Categorical comparisons of delay discounting between a psychiatric group and a control group. Results: The sample included 57 effect sizes from 43 studies across 8 diagnostic categories. Significantly steeper discounting for individuals with a psychiatric disorder compared with controls was observed for major depressive disorder (Hedges g = 0.37; P = .002; k = 7), schizophrenia (Hedges g = 0.46; P = .004; k = 12), borderline personality disorder (Hedges g = 0.60; P < .001; k = 8), bipolar disorder (Hedges g = 0.68; P < .001; k = 4), bulimia nervosa (Hedges g = 0.41; P = .001; k = 4), and binge-eating disorder (Hedges g = 0.34; P = .001; k = 7). In contrast, anorexia nervosa exhibited statistically significantly shallower discounting (Hedges g = -0.30; P < .001; k = 10). Modest evidence of publication bias was indicated by a statistically significant Egger test for schizophrenia and at the aggregate level across studies. Conclusions and Relevance: Results of this study appear to provide empirical support for delay discounting as a transdiagnostic process across most of the psychiatric disorders examined; the literature search also revealed limited studies in some disorders, notably posttraumatic stress disorder, which is a priority area for research.

Associations Between Drinking and Cortical Thickness in Younger Adult Drinkers: Findings From the Human Connectome Project.

BACKGROUND: Previous neuroimaging studies examining relations between alcohol misuse and cortical thickness have revealed that increased drinking quantity and alcohol-related problems are associated with thinner cortex. Although conflicting regional effects are often observed, associations are generally localized to frontal regions (e.g., dorsolateral prefrontal cortex [DLPFC], inferior frontal gyrus [IFG], and anterior cingulate cortex). Inconsistent findings may be attributed to methodological differences, modest sample sizes, and limited consideration of sex differences. METHODS: This study examined neuroanatomical correlates of drinking quantity and heavy episodic drinking in a large sample of younger adults (N = 706; Mage  = 28.8; 51% female) using magnetic resonance imaging data from the Human Connectome Project. Exploratory analyses examined neuroanatomical correlates of executive function (flanker task) and working memory (list sorting). RESULTS: Hierarchical linear regression models (controlling for age, sex, education, income, smoking, drug use, twin status, and intracranial volume) revealed significant inverse associations between drinks in past week and frequency of heavy drinking and cortical thickness in a majority of regions examined. The largest effect sizes were found for frontal regions (DLPFC, IFG, and the precentral gyrus). Follow-up regression models revealed that the left DLPFC was uniquely associated with both drinking variables. Sex differences were also observed, with significant effects largely specific to men. CONCLUSIONS: This study adds to the understanding of brain correlates of alcohol use in a large, gender-balanced sample of younger adults. Although the cross-sectional methodology precludes causal inferences, these findings provide a foundation for rigorous hypothesis testing in future longitudinal investigations.