A pairwise cytokine code explains the organism-wide response to sepsis.

Sepsis is a systemic response to infection with life-threatening consequences. Our understanding of the molecular and cellular impact of sepsis across organs remains rudimentary. Here, we characterize the pathogenesis of sepsis by measuring dynamic changes in gene expression across organs. To pinpoint molecules controlling organ states in sepsis, we compare the effects of sepsis on organ gene expression to those of 6 singles and 15 pairs of recombinant cytokines. Strikingly, we find that the pairwise effects of tumor necrosis factor plus interleukin (IL)-18, interferon-gamma or IL-1ß suffice to mirror the impact of sepsis across tissues. Mechanistically, we map the cellular effects of sepsis and cytokines by computing changes in the abundance of 195 cell types across 9 organs, which we validate by whole-mouse spatial profiling. Our work decodes the cytokine cacophony in sepsis into a pairwise cytokine message capturing the gene, cell and tissue responses of the host to the disease.

Host obesity impacts genetic variation in influenza A viral populations.

Obesity is well established as a risk factor for many noncommunicable diseases; however, its consequences for infectious disease are poorly understood. Here, we investigated the impact of host obesity on influenza A virus (IAV) genetic variation using a diet-induced obesity ferret model and the A/Hong Kong/1073/1999 (H9N2) strain. Using a co-caging study design, we investigated the maintenance, generation, and transmission of intrahost IAV genetic variation by sequencing viral genomic RNA obtained from nasal wash samples over multiple days of infection. We found evidence for an enhanced role of positive selection acting on de novo mutations in obese hosts that led to nonsynonymous changes that rose to high frequency. In addition, we identified numerous cases of mutations throughout the genome that were specific to obese hosts and that were preserved during transmission between hosts. Despite detection of obese-specific variants, the overall viral genetic diversity did not differ significantly between obese and lean hosts. This is likely due to the high supply rate of de novo variation and common evolutionary adaptations to the ferret host regardless of obesity status, which we show are mediated by variation in the hemagglutinin and polymerase genes (PB2 and PB1). We also identified defective viral genomes (DVGs) that were found uniquely in either obese or lean hosts, but the overall DVG diversity and dynamics did not differ between the two groups. Our study suggests that obesity may result in a unique selective environment impacting intrahost IAV evolution, highlighting the need for additional genetic and functional studies to confirm these effects.IMPORTANCEObesity is a chronic health condition characterized by excess adiposity leading to a systemic increase in inflammation and dysregulation of metabolic hormones and immune cell populations. Influenza A virus (IAV) is a highly infectious pathogen responsible for seasonal and pandemic influenza. Host risk factors, including compromised immunity and pre-existing health conditions, can contribute to increased infection susceptibility and disease severity. During viral replication in a host, the negative-sense single-stranded RNA genome of IAV accumulates genetic diversity that may have important consequences for viral evolution and transmission. Our study provides the first insight into the consequences of host obesity on viral genetic diversity and adaptation, suggesting that host factors associated with obesity alter the selective environment experienced by a viral population, thereby impacting the spectrum of genetic variation.

Tetradentate Ligand's Chameleon-Like Behavior Offers Recognition of Specific Lanthanides.

The surging demand for high-purity individual lanthanides necessitates the development of novel and exceptionally selective separation strategies. At the heart of these separation systems is an organic compound that, based on its structural features, selectively recognizes the lighter or heavier lanthanides in the trivalent lanthanide (Ln) series. This work emphasizes the significant implications resulting from modifying the donor group configuration within an N,O-based tetradentate ligand and the changes in the solvation environment of Ln ions in the process of separating Lns, with the unique ability to achieve peak selectivity in the light, medium, and heavy Ln regions. The structural rigidity of the bis-lactam-1,10-phenanthroline ligand enforces size-based selectivity, displaying an exceptional affinity for Lns having larger ionic radii such as La. Modifying the ligand by eliminating one preorganization element (phenanthroline → bipyridine) results in the fast formation of complexes with light Lns, but, in the span of hours, the peak selectivity shifts toward middle Ln (Sm), resulting in time-resolved separation. As expected, at low nitric acid concentrations, the neutral tetradentate ligand complexes with Ln3+ ions. However, the change in extraction mechanism is observed at high nitric acid concentrations, leading to the formation and preferential extraction of anionic heavy Ln species, [Ln(NO3)x+3]x-, that self-assemble with two ligands that have undergone protonation, forming intricate supramolecular architectures. The tetradentate ligand that is structurally balanced with restrictive and unrestrictive motifs demonstrates unique, controllable selectivity for light, middle, and heavy Lns, underscoring the pivotal role of solvation and ion interactions within the first and second coordination spheres.

Translational validity of neuropsychological tasks of sustained attention between rodents and humans: A systematic review of three rodent tasks.

Atypical sustained attention is a symptom in a number of neurological and psychological conditions. Investigations into its neural underpinnings are required for improved management and treatment. Rodents are useful in investigating the neurobiology underlying atypical sustained attention and several rodent tasks have been developed for use in touchscreen testing platforms that mimic methodology used in human clinical attention assessment. This systematic review was conducted to assess how translatable these rodent tasks are to equivalent clinical human tasks. Studies using the rodent Continuous Performance Task (rCPT), Sustained Attention Task (SAT), and 5-choice CPT (5C-CPT) were sought and screened. Included in the review were 138 studies, using the rCPT (n = 21), SAT (n = 90), and 5C-CPT (n = 27). Translatability between rodent and human studies was assessed based on (1) methodological similarity, (2) performance similarity, and (3) replication of results. The 5C-CPT was found to be the most translatable cross-species paradigm with good utility, while the rCPT and SAT require adaptation and further development to meet these translatability benchmarks. With greater replication and more consistent results, greater confidence in the translation of sustained attention results between species will be engendered.

The chloroplast and mitochondrial genomes of two Gomphonema parvulum (Bacillariophyta) environmental isolates from South Carolina (United States) and Virginia (United States).

Gomphonema parvulum is a cosmopolitan freshwater diatom that is used as an indicator in water quality biomonitoring. In this study, we report the culturing of two geographically separated isolates from southeastern North America, their morphology, and the sequencing and assembly of their mitochondrial and chloroplast genomes. Morphologically, both strains fit G. parvulum sensu lato, but the frustules from a protected habitat in South Carolina were smaller than those cited in the historic data of this species from the same location as well as a second culture from Virginia. Phylogenetic analyses using the rbcL gene placed both within a clade with G. parvulum. Genetic markers, including full chloroplast and mitochondrial genomes and the nuclear small subunit rRNA gene region were assembled from each isolate. The organellar genomes of the two strains varied slightly in size due to small differences in intergenic regions with chloroplast genomes of 121,035 bp and 121,482 bp and mitochondrial genomes of 34,639 bp and 34,654 bp. The intraspecific pairwise identities of the chloroplast and mitochondrial genomes of these two isolates were 97.9% and 95.4%, respectively. Multigene phylogenetic analysis demonstrated a close relationship between G. parvulum, Gomphoneis minuta, and Didymosphenia geminata.

A cry for kelp: Evidence for polyphenolic inhibition of Oxford Nanopore sequencing of brown algae.

Genomic resources have yielded unprecedented insights into ecological and evolutionary processes, not to mention their importance in economic and conservation management of specific organisms. However, the field of macroalgal genomics is hampered by difficulties in the isolation of suitable DNA. Even when DNA that appears high quality by standard metrics has been isolated, such samples may not perform well during the sequencing process. We here have compared Oxford Nanopore long-read sequencing results for three species of macroalgae to those of nonmacroalgal species and determined that when using macroalgal samples, sequencing activity declined rapidly, resulting in reduced sequencing yield. Chemical analysis of macroalgal DNA that would be considered suitable for sequencing revealed that DNA derived from dried macroalgae was enriched for polyphenol-DNA adducts (DNA with large polyphenols chemically attached to it), which may have led to sequencing inhibition. Of note, we observed the strongest evidence of sequencing inhibition and reduced sequence output when using samples dried using silica gel-suggesting that such storage approaches may not be appropriate for samples destined for Oxford Nanopore sequencing. Our findings have wide-ranging implications for the generation of genomic resources from macroalgae and suggest a need to develop new storage methods that are more amenable to Oxford Nanopore sequencing or to use fresh flash-frozen tissue wherever possible for genome sequencing.

'A profound effect on how I see myself and the world around me': what students found meaningful about taking an academic course intended to reduce campus sexual violence.

Sexual violence is common on US college campuses and can result in negative health and academic outcomes. Credit-bearing courses are a possible innovative intervention, but few have been studied, and little is known about enrolled students' experiences. Our institution, located in the Southern United States, developed a semester-long class as a curricular intervention after our institutional climate survey results showed high rates of sexual violence among undergraduate students. Students enrolled in the course wrote a final reflection paper on what they found meaningful about the class (N = 62). Qualitative conventional content analysis was used to examine what students found most salient. Three overarching categories emerged: course content, course delivery and course impact, each with multiple themes. For course content, students wrote about 22 different topics from the class. For course delivery, students discussed the open forum to discuss sexuality, the importance of taking the course in their first year of college and the course structure. For course impact, students discussed gaining new knowledge, questioning prior assumptions, experiencing personal transformation and feeling empowered to act. Results indicated that students had a powerful class experience and that this kind of educational intervention has the potential to positively impact enrolled students.

"It feels like you have to choose one or the other": a qualitative analysis of obstetrician focus groups on periviability counseling.

OBJECTIVES: The objective of this study was to gain knowledge and ascertain challenges about periviability counseling among obstetricians to inform curricular development. METHODS: Focus groups were utilized. A series of open-ended questions was posed to each group of obstetricians; responses were audio recorded and transcribed. Transcriptions were analyzed by two coders using thematic analysis. RESULTS: Four focus groups were convened. Prominent themes included: (1) Obstetrician knowledge about neonatal outcomes is limited, (2) Periviability counseling is both time intensive and time-challenged, (3) Patient processing of information relies on the content, delivery and patient readiness, and (4) Obstetrician bias is toward advocating for maternal safety, which may run counter to parental instinct to "do everything." The last theme was specifically focused on the role of cesarean delivery. CONCLUSIONS: Curricula focused on improving obstetrician periviability counseling should focus on neonatal outcomes, the role of cesarean delivery, and utilization of shared decision-making.

Cerclage Plus Adjuvant Vaginal Progesterone for Preterm Birth Prevention in Patients with a Short or Dilated Cervix without Prior Preterm Birth.

OBJECTIVE: The primary objective was to determine if vaginal progesterone following cerclage for cervical length <10 mm or cervical dilation in patients without a history of spontaneous preterm birth (sPTB) decreased the risk of preterm birth at <34 weeks' gestation compared with cerclage alone. Secondary objectives were to determine if vaginal progesterone following cerclage (1) decreased the risk of preterm birth at <24, <28, and <37 weeks' gestation and (2) increased the latency period from cerclage placement to delivery compared with treatment with cerclage alone. STUDY DESIGN: Multicenter retrospective cohort study from 2015 to 2020 of singleton pregnancies, without prior sPTB, who had cerclage placement <24 weeks' gestation for cervical length <10 mm or cervical dilation. Exposure defined as cerclage plus vaginal progesterone postoperatively (dual therapy) and unexposed as cerclage alone (monotherapy), based on surgeon preference. RESULTS: We included 122 patients, 78 (64%) treated with dual therapy and 44 (36%) treated with monotherapy. In the crude analysis, dual therapy was associated with a lower risk of delivery at <28 weeks' gestation (13%) compared with monotherapy (34%; crude risk ratio: 0.38 [95% confidence interval (CI): 0.19-0.75]). When adjusted for preoperative vaginal progesterone, results were attenuated (adjusted risk ratio: 0.45 [95% CI: 0.20-1.01]). In both the crude and adjusted analyses, the risk of sPTB was not statistically different at <24, <34 or <37 weeks' gestation. Dual therapy was associated with a greater pregnancy latency from cerclage to delivery (16.3 vs. 14.4 weeks; p = 0.04), and greater gestational age at delivery (37.3 vs. 35.8 weeks' gestation; p = 0.02) compared with monotherapy. CONCLUSION: While not statistically significant, the risk of sPTB was lower at all gestational ages studied in patients treated with dual therapy compared with monotherapy. Dual therapy was associated with longer pregnancy latency and greater gestational age at delivery compared with monotherapy. KEY POINTS: · Dual therapy did not decrease preterm birth risk compared with monotherapy.. · Dual therapy prolonged pregnancy compared with monotherapy.. · Dual therapy can be considered but further studies are needed..

Benefit-Cost Analysis for Earthquake-Resilient Building Design and Retrofit: State of the Art and Future Research Needs.

This paper reviews the state of the art in using benefit-cost analysis (BCA) to inform earthquake risk reduction decisions by building owners and policymakers. The goal is to provide a roadmap for the application and future development of BCA methods and tools for earthquake risk reduction. Our review covers three earthquake risk reduction measures: adopting up-to-date building codes for new construction, designing new buildings to exceed code requirements, and retrofitting deficient existing buildings. We highlight the factors that influence the cost-effectiveness of building design and retrofit, as well as tactics for increasing the cost-effectiveness of risk reduction strategies. We also present BCA results, methods, and data sources used in the literature to help researchers and practitioners design and conduct a reliable and robust BCA study. In the process, we develop a set of opportunities and challenges for applying BCA to new areas of research, as well as key gaps and limitations in current BCA approaches, including further investigation of above-code design, incorporation of code implementation and enforcement into BCA, quantification of environmental benefits of seismic retrofits, and optimization of seismic retrofits with energy upgrades. Overall, our review provides practical guidance and useful insights into BCA with the goal of increasing the earthquake resilience and economic efficiency of buildings in the United States.

Structurally Conserved Domains between Flavivirus and Alphavirus Fusion Glycoproteins Contribute to Replication and Infectious-Virion Production.

Alphaviruses and flaviviruses have class II fusion glycoproteins that are essential for virion assembly and infectivity. Importantly, the tip of domain II is structurally conserved between the alphavirus and flavivirus fusion proteins, yet whether these structural similarities between virus families translate to functional similarities is unclear. Using in vivo evolution of Zika virus (ZIKV), we identified several novel emerging variants, including an envelope glycoprotein variant in ß-strand c (V114M) of domain II. We have previously shown that the analogous ß-strand c and the ij loop, located in the tip of domain II of the alphavirus E1 glycoprotein, are important for infectivity. This led us to hypothesize that flavivirus E ß-strand c also contributes to flavivirus infection. We generated this ZIKV glycoprotein variant and found that while it had little impact on infection in mosquitoes, it reduced replication in human cells and mice and increased virus sensitivity to ammonium chloride, as seen for alphaviruses. In light of these results and given our alphavirus ij loop studies, we mutated a conserved alanine at the tip of the flavivirus ij loop to valine to test its effect on ZIKV infectivity. Interestingly, this mutation inhibited infectious virion production of ZIKV and yellow fever virus, but not West Nile virus. Together, these studies show that shared domains of the alphavirus and flavivirus class II fusion glycoproteins harbor structurally analogous residues that are functionally important and contribute to virus infection in vivo.IMPORTANCE Arboviruses are a significant global public health threat, yet there are no antivirals targeting these viruses. This problem is in part due to our lack of knowledge of the molecular mechanisms involved in the arbovirus life cycle. In particular, virus entry and assembly are essential processes in the virus life cycle and steps that can be targeted for the development of antiviral therapies. Therefore, understanding common, fundamental mechanisms used by different arboviruses for entry and assembly is essential. In this study, we show that flavivirus and alphavirus residues located in structurally conserved and analogous regions of the class II fusion proteins contribute to common mechanisms of entry, dissemination, and infectious-virion production. These studies highlight how class II fusion proteins function and provide novel targets for development of antivirals.

Supplementation With Iron Syrup or Iron-Containing Multiple Micronutrient Powders Alters Resting Brain Activity in Bangladeshi Children.

BACKGROUND: Anemia and iron deficiency have been associated with poor child cognitive development. A key rationale for the prevention of anemia using supplementation with iron has been the benefits to neurodevelopment. However, little causal evidence exists for these gains. OBJECTIVES: We aimed to examine effects of supplementation with iron or multiple micronutrient powders (MNPs) on brain activity measures using resting electroencephalography (EEG). METHODS: Children included in this neurocognitive substudy were randomly selected from the Benefits and Risks of Iron Supplementation in Children study, a double-blind, double-dummy, individually randomized, parallel-group trial in Bangladesh, in which children, starting at 8 mo of age, received 3 mo of daily iron syrup, MNPs, or placebo. Resting brain activity was recorded using EEG immediately after intervention (month 3) and after a further 9-month follow-up (month 12). We derived EEG band power measures for delta, theta, alpha, and beta frequency bands. Linear regression models were used to compare the effect of each intervention with that of placebo on the outcomes. RESULTS: Data from 412 children at month 3 and 374 at month 12 were analyzed. At baseline, 43.9% were anemic and 26.7% were iron deficient. Immediately after intervention, iron syrup, but not MNPs, increased the mu alpha-band power, a measure that is associated with maturity and the production of motor actions (iron vs. placebo: mean difference = 0.30; 95% CI: 0.11, 0.50 µV2; P = 0.003; false discovery rate adjusted P = 0.015). Despite effects on hemoglobin and iron status, effects were not observed on the posterior alpha, beta, delta, and theta bands, nor were effects sustained at the 9-month follow-up. CONCLUSIONS: The effect size for immediate effects on the mu alpha-band power is comparable in magnitude with psychosocial stimulation interventions and poverty reduction strategies. However, overall, we did not find evidence for long-lasting changes in resting EEG power spectra from iron interventions in young Bangladeshi children. This trial was registered at www.anzctr.org.au as ACTRN12617000660381.

Does the impact of bereavement vary between same and different gender partnerships? A representative national, cross-sectional study.

BACKGROUND: Data suggest poorer bereavement outcomes for lesbian, gay and bisexual people, but this has not been estimated in population-based research. This study compared bereavement outcomes for partners of same-gender and different-gender decedents. METHODS: In this population-based, cross-sectional survey of people bereaved of a civil partner or spouse 6-10 months previously, we used adjusted logistic and linear regression to investigate outcomes of interest: (1) positive screen on Inventory of Complicated Grief (ICG), (2) positive screen on General Health Questionnaire (GHQ), (3) grief intensity (ICG) and (4) psychiatric symptoms (GHQ-12). RESULTS: Among 233 same-gender partners and 329 of different-gender partners, 66.1% [95% confidence interval (CI) 60.0-72.2] and 59.2% [95% CI (53.9-64.6)] respectively screened positive for complicated grief on the ICG, whilst 76.0% [95% CI (70.5-81.5)] and 69.3% [95% CI (64.3-74.3)] respectively screened positive on the GHQ-12. Same-gender bereaved partners were not significantly more likely to screen positive for complicated grief than different-gender partners [adjusted odds ratio (aOR) 1.56, 95% CI (0.98-2.47)], p = 0.059, but same-gender bereaved partners were significantly more likely to screen for psychiatric caseness [aOR 1.67 (1.02, 2.71) p = 0.043]. We similarly found no significant association of partner gender with grief intensity [B = 1.86, 95% CI (-0.91to 4.63), p = 0.188], but significantly greater psychological distress for same-gender partners [B = 1.54, 95% CI (-0.69-2.40), p < 0.001]. CONCLUSIONS: Same-gender bereaved partners report significantly more psychological distress. In view of their poorer sub-clinical mental health, clinical and bereavement services should refine screening processes to identify those at risk of poor mental health outcomes.

LGBT+ partner bereavement and appraisal of the Acceptance-Disclosure Model of LGBT+ bereavement: A qualitative interview study.

BACKGROUND: Support from social networks is vital after the death of a partner. Lesbian, gay, bisexual and/or transgender (LGBT+) people can face disenfranchisement and isolation in bereavement. The Acceptance-Disclosure Model (of LGBT+ bereavement) posits that experiences are shaped by the extent to which individuals feel able to disclose their bereavement to others, and whether that loss is acknowledged appropriately. AIM: To explore LGBT+ specific experiences of partner bereavement; determine decision-making processes regarding disclosure of relationships/identities; and appraise the Acceptance-Disclosure Model using primary qualitative data. DESIGN: Exploratory in-depth qualitative interview study positioned within a social constructivist paradigm. Data were analysed using inductive and deductive reflexive thematic analysis. SETTING/PARTICIPANTS: 21 LGBT+ people from across England bereaved of their civil partner/spouse. RESULTS: Participants described LGBT+ specific stressors in bereavement: lack of recognition of their loss; inappropriate questioning; unwanted disclosure of gender history; and fears of discrimination when accessing support. Disclosure of LGBT+ identities varied across social networks. Some participants described hiding their identities and bereavement to preserve relationships, and challenging intersections between LGBT+ identities and other aspects of culture or self. These findings provide primary evidence to support the Acceptance-Disclosure Model. CONCLUSIONS: LGBT+ people face additional stressors in bereavement. Not all LGBT+ people want to talk directly about their relationships/identities. Sensitive exploration of support needs, aligned with preferences around disclosure of identities, can help foster trust. Five recommendations for inclusive practice are presented. Further research should consider whether the Acceptance-Disclosure Model has utility to explain bereavement experiences for other isolated or disenfranchised groups.

Direct lysosome-based autophagy of lipid droplets in hepatocytes.

Hepatocytes metabolize energy-rich cytoplasmic lipid droplets (LDs) in the lysosome-directed process of autophagy. An organelle-selective form of this process (macrolipophagy) results in the engulfment of LDs within double-membrane delimited structures (autophagosomes) before lysosomal fusion. Whether this is an exclusive autophagic mechanism used by hepatocytes to catabolize LDs is unclear. It is also unknown whether lysosomes alone might be sufficient to mediate LD turnover in the absence of an autophagosomal intermediate. We performed live-cell microscopy of hepatocytes to monitor the dynamic interactions between lysosomes and LDs in real-time. We additionally used a fluorescent variant of the LD-specific protein (PLIN2) that exhibits altered fluorescence in response to LD interactions with the lysosome. We find that mammalian lysosomes and LDs undergo interactions during which proteins and lipids can be transferred from LDs directly into lysosomes. Electron microscopy (EM) of primary hepatocytes or hepatocyte-derived cell lines supports the existence of these interactions. It reveals a dramatic process whereby the lipid contents of the LD can be "extruded" directly into the lysosomal lumen under nutrient-limited conditions. Significantly, these interactions are not affected by perturbations to crucial components of the canonical macroautophagy machinery and can occur in the absence of double-membrane lipoautophagosomes. These findings implicate the existence of an autophagic mechanism used by mammalian cells for the direct transfer of LD components into the lysosome for breakdown. This process further emphasizes the critical role of lysosomes in hepatic LD catabolism and provides insights into the mechanisms underlying lipid homeostasis in the liver.

The Multimethod Evaluation of a Curricular Intervention Intended to Reduce Sexual Violence on a College Campus: A Synthesis of Findings and Lessons Learned.

Sexual violence is a major problem on college campuses, and innovative solutions are needed. Our university created a semester-long, credit-bearing, academic course as a curricular intervention intended to reduce sexual violence on campus. In this article, we describe the multiple methods used to evaluate the course, including a pre-post online survey with a quasi-experimental design, a qualitative content analysis of student reflection papers, and semistructured interviews with previously enrolled students conducted by a peer interviewer 3 months after course completion. The synthesis of evaluation findings indicated that an academic course has the potential to positively affect campus climate around sexual violence. Furthermore, using multiple methods enabled us to create a theory of change that illustrates how key course components shaped students' knowledge, attitudes, and behaviors about sexual violence, thereby ideally generating campus change. Results have been used by various stakeholders for both practice-based and scholarly purposes. We provide lessons learned and implications for practice that are transferable to other multimethod curricular intervention evaluations regardless of topical focus, including the many ways in which using multiple methods added value to the study; the considerable investment of time and resources needed when using multiple methods; the challenges that can arise when integrating findings across methods; the major benefits of having a multidisciplinary research team consisting of faculty and students; and the need to engage in critical reflexivity.

Health-Related Social Needs Screening: Promising Practices From the Accountable Health Communities Model.

Health-related social needs (HRSNs), such as food insecurity and housing instability, drive health and well-being. The socioeconomic impacts of the COVID-19 pandemic increased the prevalence of HRSNs and highlighted the critical need for strategies to address those needs, particularly in communities experiencing health disparities. Implementing HRSN screening requires adopting effective strategies to overcome common challenges. This report synthesizes promising implementation approaches and lessons learned from the Accountable Health Communities Model, a national effort funded by the Centers for Medicare & Medicaid Services Innovation Center to systematically screen for and address HRSNs in clinical settings. Key strategies include increasing patient engagement and building trust through culturally tailored language and outreach; using and sharing data for monitoring and improvement; using technology to expand access to screening and referrals; dedicating staff to screening roles; integrating screening into existing workflows; and building buy-in among staff by communicating the impact of screening and encouraging peer connections.

Daily arousal variation has little effect on sustained attention performance.

Sustaining attention is an important cognitive process for everyday functioning and arousal is thought to underpin its performance. Primate studies depict an inverted-u relation between sustained attention and arousal, in which sustained attention performance is most affected at the extreme levels of arousal and peak performance aligns with moderate arousal. Human research findings are, however, inconsistent. This study aimed to investigate the effects of arousal on sustained attention performance in humans using two approaches-a small-N study with an inbuilt replication to test within-participant variation, and a larger sample assessing between-participant variation. The Sustained Attention to Response Task (SART) was used to measure sustained attention performance and the Karolinska Sleepiness Scale (KSS) was used to measure arousal. In the small-N study five participants completed the SART and KSS once an hour between 7 a.m. and 7 p.m., repeated two weeks later. Significant, curvilinear variation in KSS across time-of-day was found. A linear association between SART response time variability (sigma) and KSS was noted, however no other consistent associations between the SART and KSS were found. In the large-N study, 161 participants completed the SART and KSS once, at a time of day of their choosing. There were no significant relations between SART measures and the KSS, indicating that subjective sleepiness was not related to sustained attention performance. Overall, the hypothesized inverted-u relation between arousal and sustained attention performance was not found. The results suggested that diurnal arousal variation does not modify sustained attention performance in adults.

Longitudinal maturation of resting state networks: Relevance to sustained attention and attention deficit/hyperactivity disorder.

The transition from childhood to adolescence involves important neural function, cognition, and behavior changes. However, the links between maturing brain function and sustained attention over this period could be better understood. This study examined typical changes in network functional connectivity over childhood to adolescence, developmental differences in attention deficit/hyperactivity disorder (ADHD), and how functional connectivity might underpin variability in sustained attention development in a longitudinal sample. A total of 398 resting state scans were collected from 173 children and adolescents (88 ADHD, 85 control) at up to three timepoints across ages 9-14 years. The effects of age, sex, and diagnostic group on changes in network functional connectivity were assessed, followed by relationships between functional connectivity and sustained attention development using linear mixed effects modelling. The ADHD group displayed greater decreases in functional connectivity between salience and visual networks compared with controls. Lower childhood functional connectivity between the frontoparietal and several brain networks was associated with more rapid sustained attention development, whereas frontoparietal to dorsal attention network connectivity related to attention trajectories in children with ADHD alone. Brain network segregation may increase into adolescence as predicted by key developmental theories; however, participants with ADHD demonstrated altered developmental trajectories between salience and visual networks. The segregation of the frontoparietal network from other brain networks may be a mechanism supporting sustained attention development. Frontoparietal to dorsal attention connectivity can be a focus for further work in ADHD.

A mutagenesis screen for essential plastid biogenesis genes in human malaria parasites.

Endosymbiosis has driven major molecular and cellular innovations. Plasmodium spp. parasites that cause malaria contain an essential, non-photosynthetic plastid-the apicoplast-which originated from a secondary (eukaryote-eukaryote) endosymbiosis. To discover organellar pathways with evolutionary and biomedical significance, we performed a mutagenesis screen for essential genes required for apicoplast biogenesis in Plasmodium falciparum. Apicoplast(-) mutants were isolated using a chemical rescue that permits conditional disruption of the apicoplast and a new fluorescent reporter for organelle loss. Five candidate genes were validated (out of 12 identified), including a triosephosphate isomerase (TIM)-barrel protein that likely derived from a core metabolic enzyme but evolved a new activity. Our results demonstrate, to our knowledge, the first forward genetic screen to assign essential cellular functions to unannotated P. falciparum genes. A putative TIM-barrel enzyme and other newly identified apicoplast biogenesis proteins open opportunities to discover new mechanisms of organelle biogenesis, molecular evolution underlying eukaryotic diversity, and drug targets against multiple parasitic diseases.