Adipokines measured during pregnancy and at birth are associated with infant negative affect.

BACKGROUND: Increased adiposity during pregnancy may be related to offspring risk for mental health disorders, although the biological mechanisms are poorly understood. One promising hypothesis is that factors secreted from adipocytes such as leptin and adiponectin may explain this association. The current study examined whether pregnancy or umbilical cord blood concentrations of leptin and/or adiponectin a) predict elevated infant negative affect at 6 months (an early life marker of risk for psychopathology); and b) help explain the association between pregnancy adiposity and increased infant negative affect. METHODS: Data came from a prospective cohort (N = 305) of pregnant individuals and their offspring. Second trimester adiposity was assessed using air displacement plethysmography. Concentrations of leptin and adiponectin were measured in second trimester plasma and umbilical cord plasma. Infant negative affect was assessed by standardized observation at 6 months. Second trimester inflammation was assessed using a comprehensive panel of cytokines. RESULTS: Lower second trimester adiponectin was associated with elevated infant negative affect, and mediated the effect of pregnancy adiposity on infant negative affect. This association was independent of the effect of second trimester inflammation. Umbilical cord leptin also predicted higher infant negative affect and mediated the association between pregnancy adiposity and infant negative affect. CONCLUSIONS: This is the first study to link pregnancy adiponectin or cord blood leptin to infant markers of risk for psychopathology, and the first to demonstrate that these adipokines mediate the association between pregnancy adiposity and offspring behavioral outcomes, suggesting novel markers of risk and potential mechanisms of effect.

Underrepresentation of racial and ethnic minority groups in gynecologic oncology: An analysis of over 250 trials.

OBJECTIVE: To describe the participation of racial and ethnic minority groups (REMGs) in gynecologic oncology trials. METHODS: Gynecologic oncology studies registered on ClinicalTrials.gov between 2007 and 2020 were identified. Trials with published results were analyzed based on reporting of race/ethnicity in relation to disease site and trial characteristics. Expected enrollment by race/ethnicity was calculated and compared to actual enrollment, adjusted for 2010 US Census population data. RESULTS: 2146 gynecologic oncology trials were identified. Of published trials (n = 252), 99 (39.3%) reported race/ethnicity data. Recent trials were more likely to report these data (36% from 2007 to 2009; 51% 2013-2015; and 53% from 2016 to 2018, p = 0.01). Of all trials, ovarian cancer trials were least likely to report race/ethnicity data (32.1% vs 39.3%, p = 0.011). Population-adjusted under-enrollment for Blacks was 7-fold in ovarian cancer, Latinx 10-fold for ovarian and 6-fold in uterine cancer trials, Asians 2.5-fold in uterine cancer trials, and American Indian and Alaska Native individuals 6-fold in ovarian trials. Trials for most disease sites have enrolled more REMGs in recent years - REMGs made up 19.6% of trial participants in 2007-2009 compared to 38.1% in 2016-2018 (p < 0.0001). CONCLUSION: Less than half of trials that published results reported race/ethnicity data. Available data reveals that enrollment of REMGs is significantly below expected rates based on national census data. These disparities persisted even after additionally adjusting for population size. Despite improvement in recent years, additional recruitment of REMGs is needed to achieve more representative and equitable participation in gynecologic cancer clinical trials.

Home indoor air quality and cognitive function over one year for people working remotely during COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic triggered an increase in remote work-from-home for office workers. Given that many homes now function as offices despite not being designed to support office work, it is critical to research the impact of indoor air quality (IAQ) in homes on the cognitive performance of people working from home. In this study, we followed 206 office workers across the U.S. over one year under remote or hybrid-remote settings during 2021-2022. Participants placed two real-time, consumer-grade indoor environmental monitors in their home workstation area and bedroom. Using a custom smartphone application geofenced to their residential address, participants responded to surveys and periodic cognitive function tests, including the Stroop color-word interference test, Arithmetic two-digit addition/subtraction test, and Compound Remote Associates Task (cRAT). Exposures assessed included carbon dioxide (CO2) and thermal conditions (indoor heat index: a combination of temperature and relative humidity) averaged over 30 minutes prior to each cognitive test. In fully adjusted longitudinal mixed models (n≤121), we found that indoor thermal conditions at home were associated with cognitive function outcomes non-linearly (p<0.05), with poorer cognitive performance on the Stroop test and poorer creative problem-solving on the cRAT when conditions were either too warm or too cool. Most indoor CO2 levels were <640 ppm, but there was still a slight association between higher CO2 and poorer cognitive performance on Stroop (p=0.09). Our findings highlight the need to enhance home indoor environmental quality for optimal cognitive function during remote work, with benefits for both employees and employers.

Elucidation of the DNA-Binding Activity of VirF from Shigella flexneri for the icsA and rnaG Promoters and Characterization of the N-Terminal Domain To Identify Residues Crucial for Dimerization.

A novel approach to treat the highly virulent and infectious enteric pathogen Shigella flexneri, with the potential for reduced resistance development, is to target virulence pathways. One promising such target is the AraC-family transcription factor VirF, which activates downstream virulence factors. VirF harbors a conserved C-terminal DNA-binding domain (DBD) and an N-terminal dimerization domain (NTD). Previously, we studied the wild type (WT) and seven alanine DBD mutants of VirF binding to the virB promoter (N. J. Ragazzone, G. T. Dow, and A. Garcia, J Bacteriol 204:e00143-22, 2022, https://doi.org/10.1128/jb.00143-22). Here, we report studies of VirF binding to the icsA and rnaG promoters. Gel shift assays (electrophoretic mobility shift assays [EMSAs]) of WT VirF binding to these promoters revealed multiple bands at higher apparent molecular weights, indicating the likelihood of VirF dimerization when bound to DNA. For three of the mutants, we observed consistent effects on binding to the three promoters. For the four other mutants, we observed differential effects on promoter binding. Results of a cell-based, LexA monohybrid ß-galactosidase reporter assay [D. A. Daines, M. Granger-Schnarr, M. Dimitrova, and R. P. Silver, Methods Enzymol 358:153-161, 2002, https://doi.org/10.1016/s0076-6879(02)58087-3] indicated that WT VirF dimerizes in vivo and that alanine mutations to Y132, L137, and L147 significantly reduced dimerization. However, these mutations negatively impacted protein stability. We did purify enough of the Y132A mutant to determine that it binds in vitro to the virB and rnaG promoters, albeit with weaker affinities. Full-length VirF model structures, generated with I-TASSER, predict that these three amino acids are in a "dimerization" helix in the NTD, consistent with our results. IMPORTANCE Antimicrobial-resistant (AMR) infections continue to rise dramatically, and the lack of new approved antibiotics is not ameliorating this crisis. A promising route to reduce AMR is by targeting virulence. The Shigella flexneri virulence pathway is a valuable source for potential therapeutic targets useful to treat this infection. VirF, an AraC-family virulence transcription factor, is responsible for activating necessary downstream virulence genes that allow the bacteria to invade and spread within the human colon. Previous studies have identified how VirF interacts with the virB promoter and have even developed a lead DNA-binding inhibitor, but not much is known about VirF dimerization or binding to the icsA and rnaG promoters. Fully characterizing VirF can be a valuable resource for inhibitor discovery/design.

Predictors of Preexposure Prophylaxis Eligibility among Pregnant People with Opioid Use Disorder.

OBJECTIVE: We seek to evaluate risk factors for eligibility for preexposure prophylaxis (PrEP) among pregnant people with opioid use disorder (OUD). STUDY DESIGN: This is a single-site retrospective cohort study of pregnant people admitted for management of OUD at an urban, tertiary care center from 2013 to 2022. PrEP eligibility was defined based on (1) modified American College of Obstetricians and Gynecologists' (ACOG) 2014 criteria: diagnosis of a sexually transmitted infection (STI), engagement in transactional sex work, intravenous drug use (IVDU), or incarceration and (2) modified 2021 Centers for Disease Control (CDC) criteria: diagnosis of bacterial STI (e.g., gonorrhea or syphilis) or transactional sex work. Risk factors associated with PrEP eligibility were evaluated using chi- square or Fischer's exact tests for categorical variables and t-tests or Wilcoxon rank-sum tests for continuous variables. Multivariable regression was used to control for confounding covariates, defined as p < 0.10 on bivariate analysis. p < 0.05 was used to indicate statistical significance. RESULTS: A total of 132 individuals met inclusion criteria, of whom 101 (76.5%) were deemed eligible for PrEP by meeting one or more modified 2014 ACOG criteria: 42 (31.8%) were incarcerated or had one or more STIs, while 30 (22.7%) endorsed engaging in transactional sex work and 68 (58.6%) endorsed IVDU. Using modified 2021 CDC criteria, 37 (28%) met PrEP eligibility, with 12 (9.1%) diagnosed specifically with a bacterial STI and 30 (22.7%) engaging in transactional sex work. Only comorbid psychiatric illness was associated with an increased risk for PrEP eligibility based on 2014 criteria, which persisted after controlling for maternal race/ethnicity (aRR 1.52, 95% confidence interval [CI] 1.24-1.86), and 2021 criteria, which persisted after controlling for nulliparity (aRR 2.12, 95% CI 1.30-3.57). CONCLUSION: A significant number of pregnant people with OUD meet one or more criteria for PrEP, with comorbid psychiatric conditions increasing the risk of meeting criteria. KEY POINTS: · Comorbid psychiatric illness is significantly associated with high risk of PrEP eligibility.. · A large proportion of pregnant individuals with active OUD meet criteria for PrEP prescribing.. · Risk-based screening algorithms for PrEP eligibility have limitations..

Coevolution of relative brain size and life expectancy in parrots.

Previous studies have demonstrated a correlation between longevity and brain size in a variety of taxa. Little research has been devoted to understanding this link in parrots; yet parrots are well-known for both their exceptionally long lives and cognitive complexity. We employed a large-scale comparative analysis that investigated the influence of brain size and life-history variables on longevity in parrots. Specifically, we addressed two hypotheses for evolutionary drivers of longevity: the cognitivebuffer hypothesis, which proposes that increased cognitive abilities enable longer lifespans, and the expensive brain hypothesis, which holds that increases in lifespan are caused by prolonged developmental time of, and increased parental investment in, large-brained offspring. We estimated life expectancy from detailed zoo records for 133 818 individuals across 244 parrot species. Using a principled Bayesian approach that addresses data uncertainty and imputation of missing values, we found a consistent correlation between relative brain size and life expectancy in parrots. This correlation was best explained by a direct effect of relative brain size. Notably, we found no effects of developmental time, clutch size or age at first reproduction. Our results suggest that selection for enhanced cognitive abilities in parrots has in turn promoted longer lifespans.

The 2016 Presidential Election and Prenatal Care Utilization Among Foreign-born Hispanic Pregnant People.

BACKGROUND: Few studies have evaluated the relationship between adequate and timely prenatal care among immigrant pregnant people and the recent political climate, including the 2016 election and associated campaigns. OBJECTIVES: We examine whether the 2016 presidential election was associated with changes in prenatal care utilization among US foreign-born Hispanic pregnant people. RESEARCH DESIGN: Interrupted time series. SUBJECTS: All foreign-born Hispanic and US-born non-Hispanic White people delivering singleton infants from 2008 to 2017 who resided in the 23 states that fully implemented the 2003 version of the birth certificate before January 2008 (n=12,397,503). MEASURES: We examine the relationship between the presidential election and changes in the odds of inadequate or late/no prenatal care among immigrant Hispanic pregnant people, as well as trends in prenatal care utilization before the election. RESULTS: Our results show no unexpected changes in receipt of inadequate prenatal care, and late/no prenatal care, among the 7 monthly conception cohorts exposed to the election before the third trimester. However, we detected increases in the odds of both inadequate care and late/no prenatal care among foreign-born Hispanic pregnant people in June 2015 and January 2016, respectively. These upward level shifts persisted through the remainder of our time series ending with the cohort conceived around December 2016. CONCLUSIONS: The worsening shifts in prenatal care utilization we observe may serve as a bellwether for worsening outcomes among immigrant women and their families. Research is therefore urgently needed to investigate the determinants and consequences of these concerning trends.

Organic Fluorine as an Indicator of Per- and Polyfluoroalkyl Substances in Dust from Buildings with Healthier versus Conventional Materials.

Per- and polyfluoroalkyl substances (PFAS) are a class of thousands of persistent, organic fluorinated chemicals added to materials and products mainly to repel stains and water. PFAS have been associated with many adverse human health effects. We aimed to determine whether buildings with "healthier" materials─defined here as reportedly free of all PFAS─exhibit lower PFAS in dust. In addition to analyzing targeted PFAS with available commercial standards, we measured extractable organic fluorine (EOF) as a novel proxy that includes both known and unknown types of PFAS. We measured at least 15 targeted PFAS (n = 24), EOF (n = 24), and total fluorine (TF; n = 14) in dust collected from university common spaces and classrooms, half of which had "healthier" furniture and carpet. We observed lower PFAS contamination in buildings with "healthier" materials: "healthier" rooms had a 66% lower median summed PFAS and a 49% lower Kaplan-Meier estimated mean EOF level in dust in comparison to conventional rooms. The summed targeted PFAS were significantly correlated with EOF but accounted for up to only 9% of EOF, indicating the likely presence of unidentified PFAS. EOF levels explained less than 1% of TF in dust. We emphasize the need to use chemical class-based methods (e.g., EOF) for evaluating class-based solutions and to expand non-PFAS solutions for other building materials.

Indoor humidity levels and associations with reported symptoms in office buildings.

Moderate indoor relative humidity (RH) levels (i.e., 40%-60%) may minimize transmission and viability of some viruses, maximize human immune function, and minimize health risks from mold, yet uncertainties exist about typical RH levels in offices globally and about the potential independent impacts of RH levels on workers' health. To examine this, we leveraged one year of indoor RH measurements (which study participants could view in real time) in 43 office buildings in China, India, Mexico, Thailand, the United Kingdom, and the United States, and corresponding self-report symptom data from 227 office workers in a subset of 32 buildings. In the buildings in this study, 42% of measurements during 9:00 - 17:00 on weekdays were less than 40% RH and 7% exceeded 60% RH. Indoor RH levels tended to be lower in less tropical regions, in winter months, when outdoor RH or temperature was low, and late in the workday. Furthermore, we also found statistically significant evidence that higher indoor RH levels across the range of 14%-70% RH were associated with lower odds of reporting dryness or irritation of the throat and skin among females and unusual fatigue among males in models adjusted for indoor temperature, country, and day of year.

Contextual factors associated with gender-based violence and related homicides perpetrated by partners and in-laws: A study of women survivors in India.

Gender based violence (GBV) is a significant public health concern for women globally, including countries such as India. The researchers investigated factors related to GBV and GBV-related homicides perpetrated by both husbands and in-laws using a qualitative approach. Data were collected from 27 women in India. Analysis revealed factors at the societal/cultural (e.g. dowry), community (e.g. inadequate resources), relationship (e.g. in-laws abuse) and individual (e.g. internalized powerlessness) levels. Findings highlight the need for culturally appropriate risk assessment and safety planning procedures, as well as policies and programs across different ecological levels to reduce risk for GBV and GBV-related homicides.

Impact of animal programming on children's attitudes toward local wildlife.

Attitudes toward wildlife can have direct implications on children's interest in conservation behaviors. Animal programs are an example of interactive, educational experiences that have the potential to change attitudes by providing individuals the opportunity to get close to animal ambassadors and participate in engaging conversations about them. We conducted an animal program assessment with summer camps at the Ohio Wildlife Center to quantify changes in children's affiliation with local wildlife and their willingness to live near local wildlife. Campers showed an overall increase in affiliation and willingness scores from before to after an animal program, although with a small effect size. Overall willingness scores were lower than affiliation scores, but there was a significantly larger increase in willingness following the program. We found a strong correlation between affiliation and willingness scores. Overall, the study found that these animal programs positively influenced children's attitudes toward local wildlife and increased their willingness to live near them, suggesting animal programming could be used to decrease human-wildlife conflict. Visually seeing animals in the programs improved attitude scores, even for those not seen in this study, which suggests that program animals can act as an ambassador for other species. This opens the potential for utilizing animal ambassadors as powerful tools in conservation education about threatened and endangered species.

Impact of Sources of Strengths on Coping and Safety of Immigrant Survivors of Intimate Partner Violence.

Intimate partner violence (IPV) is a national and international public health and human rights concern. Immigrant women are disproportionately affected by IPV that includes homicides. This study explored the perspectives of survivors of IPV, who are immigrants to the United States, regarding their sources of strength that enhance their safety and promote coping in abusive relationships. Data for this qualitative study were collected from ethnically diverse immigrant women residing in Massachusetts, Arizona, Virginia, Washington, D.C., New York, Minnesota, and California, using purposive and snowball sampling techniques. Eighty-three in-depth interviews were conducted with adult immigrant survivors of IPV who self-identified as Asian (n = 30), Latina (n = 30), and African (n = 23). Data were analyzed using thematic analysis. Women identified both external (e.g., community support, support from social service agencies) and internal (e.g., optimism, faith, beliefs) sources of strength. The study highlights how these sources can adequately address needs of survivors and offers areas for improvement in services for survivors. The findings are informative for practitioners serving immigrant survivors of IPV in legal, social service, and physical and mental health settings.

Trajectories of perinatal depressive symptoms in the context of the COVID-19 pandemic.

This study sought to advance understanding of the potential long-term consequences of the COVID-19 pandemic for child development by characterizing trajectories of maternal perinatal depression, a common and significant risk factor for adverse child outcomes. Data came from 393 women (86% White, 8% Latina; mean age = 33.51 years) recruited during pregnancy (n = 247; mean gestational age = 22.94 weeks) or during the first year postpartum (n = 146; mean child age = 4.50 months; 55% female). Rates of depression appear elevated, relative to published reports and to a pre-pandemic comparison group (N = 155). This study also provides evidence for subgroups of individuals who differ in their depressive symptom trajectories over the perinatal period. Subgroup membership was related to differences in maternal social support, but not to child birth outcomes.

Obstetrical care is associated with child's dietary diversity in Indonesia: analysis from Demographic and Health Survey 2017.

OBJECTIVE: To explore the influence of obstetrical care factors on dietary diversity and individual food group consumption in Indonesia. DESIGN: Cross-sectional study to assess the association between pregnancy care factors and dietary diversity score, minimum dietary diversity (MDD) and consumption of seven food groups. SETTING: Data from the Indonesia Demographic and Health Survey 2017. PARTICIPANTS: A total of 5113 children aged 6-23 months. RESULTS: Dietary diversity score was significantly higher for children whose mothers received four or more prenatal care visits, were delivered at a health facility, had a professionally trained delivery assistant and were delivered by C-section. Children born at a health facility and delivered by a health professional had higher odds of meeting MDD (adjusted OR (AOR) 1·45, 95 % CI 1·18, 1·79 and OR 2·10, 95 % CI 1·54, 2·87, respectively). Four or more antenatal visits, delivering at a health facility and having a professional delivery attendant were associated with higher odds of consumption of lentils (AOR 1·66, 95 % CI 1·23, 2·25, AOR 1·30, 95 % CI 1·02, 1·65 and AOR 1·79, 95 % CI 1·19, 2·69). Four or more antenatal visits, delivering at a health facility and having a professional delivery attendant had higher odds of consumption of other fruits and vegetables (AOR 1·70, 95 % CI 1·23, 2·35, OR 1·23, 95 % CI 1·03, 1·61 and OR 1·90, 95 % CI 1·29, 2·79). CONCLUSIONS: Efforts focusing on providing nutritional education during antenatal care and delivery should be encouraged, especially for mothers seeking care outside of a health facility.

Identification of Tumor Antigens in Ovarian Cancers Using Local and Circulating Tumor-Specific Antibodies.

Ovarian cancers include several disease subtypes and patients often present with advanced metastatic disease and a poor prognosis. New biomarkers for early diagnosis and targeted therapy are, therefore, urgently required. This study uses antibodies produced locally in tumor-draining lymph nodes (ASC probes) of individual ovarian cancer patients to screen two separate protein microarray platforms and identify cognate tumor antigens. The resulting antigen profiles were unique for each individual cancer patient and were used to generate a 50-antigen custom microarray. Serum from a separate cohort of ovarian cancer patients encompassing four disease subtypes was screened on the custom array and we identified 28.8% of all ovarian cancers, with a higher sensitivity for mucinous (50.0%) and serous (40.0%) subtypes. Combining local and circulating antibodies with high-density protein microarrays can identify novel, patient-specific tumor-associated antigens that may have diagnostic, prognostic or therapeutic uses in ovarian cancer.

The Effects of Ventilation and Filtration on Indoor PM2.5 in Office Buildings in Four Countries.

Fine particulate matter (PM2.5) is an airborne pollutant associated with negative acute and chronic human health outcomes. Although the majority of PM2.5 research has focused on outdoor exposures, people spend the majority of their time indoors, where PM2.5 of outdoor origin can penetrate. In this work, we measured indoor PM2.5 continuously for one year in 37 urban commercial offices with mechanical or mixed-mode ventilation in China, India, the United Kingdom, and the United States. We found that indoor PM2.5 concentrations were generally higher when and where outdoor PM2.5 was elevated. In India and China, mean workday indoor PM2.5 levels exceeded the World Health Organization's 24-hour exposure guideline of 25 µg/m3 about 17% and 27% of the time, respectively. Our statistical models found evidence that the operation of mechanical ventilation systems could mitigate the intrusion of outdoor PM2.5: during standard work hours, a 10 µg/m3 increase in outdoor PM2.5 was associated with 19.9% increase in the expected concentration of indoor PM2.5 (p<0.0001), compared to a larger 23.4% increase during non-work hours (p<0.0001). Finally, our models found that using filters with ratings of MERV 13-14 or MERV 15+ was associated with a 30.9% (95% CI: -55.0%, +6.2%) or 39.4% (95% CI: -62.0%, -3.4%) reduction of indoor PM2.5, respectively, compared to filters with lower MERV 7-12 ratings. Our results demonstrate the potential efficacy of mechanical ventilation with efficient filtration as a public health strategy to protect workers from PM2.5 exposure, particularly where outdoor levels of PM2.5 are elevated.

Phthalate and Organophosphate Plasticizers in Nail Polish: Evaluation of Labels and Ingredients.

In the 2000s, nail polish manufacturers started promoting "3-Free" products, phasing out three widely publicized toxic chemicals: toluene, formaldehyde, and dibutyl phthalate (DnBP). However, DnBP was sometimes replaced by another endocrine-disrupting plasticizer, triphenyl phosphate (TPHP). Many new " n-Free" labels have since appeared, without any standardization on which n chemicals are excluded. This study aimed to compare measured plasticizer content against nail polish labels. First, we summarized definitions of labels. Then, we measured 12 phthalate and 10 organophosphate plasticizers in 40 nail polishes from 12 brands selected for popularity and label variety. We found labels ranging from 3- to 13-Free; 10-Free was the most inconsistently defined (six definitions). Our samples contained TPHP and bis(2-ethylhexyl) phthalate (DEHP) at up to 7940 and 331 µg/g, respectively. The 5- to 13-Free samples had lower TPHP levels than unlabeled or 3-Free samples (median <0.002 vs 3730 µg/g, p < 0.001). The samples that did not contain TPHP had higher DEHP levels (median 68.5 vs 1.51 µg/g, p < 0.05). We measured plasticizers above 100 µg/g in five brands that did not disclose them and in two that excluded them in labels. This study highlights inconsistencies in nail polish labels and identifies TPHP and DEHP as ingredient substitutes for DnBP.

A rapid and reagent-free bioassay for the detection of dioxin-like compounds and other aryl hydrocarbon receptor (AhR) agonists using autobioluminescent yeast.

An autonomously bioluminescent Saccharomyces cerevisiae BLYAhS bioreporter was developed in this study for the simple and rapid detection of dioxin-like compounds (DLCs) and aryl hydrocarbon receptor (AhR) agonists. This recombinant yeast reporter was based on a synthetic bacterial luciferase reporter gene cassette (lux) that can produce the luciferase as well as the enzymes capable of self-synthesizing the requisite substrates for bioluminescent production from endogenous cellular metabolites. As a result, bioluminescent signal production is generated continuously and autonomously without cell lysis or exogenous reagent addition. By linking the expression of the autobioluminescent lux reporter cassette to AhR activation via the use of a dioxin-responsive promoter, the S. cerevisiae BLYAhS bioreporter emitted a bioluminescent signal in response to DLC exposure in a dose-responsive manner. The model dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), could be detected within 4 h with a half maximal effective concentration (EC50) of ~ 8.1 nM and a lower detection limit of 500 pM. The autobioluminescent response of BLYAhS to other AhR agonists, including 2,3,7,8-tetrachlorodibenzofuran (TCDF), polychlorinated bisphenyl congener 126 (PCB-126) and 169 (PCB-169), 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (HxCDD), 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD), benzo[a]pyrene (BaP), and ß-naphthoflavone (bNF), were also characterized in this study. The non-destructive and reagent-free nature of the BLYAhS reporter assay facilitated near-continuous, automated signal acquisition without additional hands-on effort and cost, providing a simple and cost-effective method for rapid DLC detection.

Coupled chaperone action in folding and assembly of hexadecameric Rubisco.

Form I Rubisco (ribulose 1,5-bisphosphate carboxylase/oxygenase), a complex of eight large (RbcL) and eight small (RbcS) subunits, catalyses the fixation of atmospheric CO(2) in photosynthesis. The limited catalytic efficiency of Rubisco has sparked extensive efforts to re-engineer the enzyme with the goal of enhancing agricultural productivity. To facilitate such efforts we analysed the formation of cyanobacterial form I Rubisco by in vitro reconstitution and cryo-electron microscopy. We show that RbcL subunit folding by the GroEL/GroES chaperonin is tightly coupled with assembly mediated by the chaperone RbcX(2). RbcL monomers remain partially unstable and retain high affinity for GroEL until captured by RbcX(2). As revealed by the structure of a RbcL(8)-(RbcX(2))(8) assembly intermediate, RbcX(2) acts as a molecular staple in stabilizing the RbcL subunits as dimers and facilitates RbcL(8) core assembly. Finally, addition of RbcS results in RbcX(2) release and holoenzyme formation. Specific assembly chaperones may be required more generally in the formation of complex oligomeric structures when folding is closely coupled to assembly.

Hsc70-induced changes in clathrin-auxilin cage structure suggest a role for clathrin light chains in cage disassembly.

The molecular chaperone, Hsc70, together with its co-factor, auxilin, facilitates the ATP-dependent removal of clathrin during clathrin-mediated endocytosis in cells. We have used cryo-electron microscopy to determine the 3D structure of a complex of clathrin, auxilin(401-910) and Hsc70 at pH 6 in the presence of ATP, frozen within 20 seconds of adding Hsc70 in order to visualize events that follow the binding of Hsc70 to clathrin and auxilin before clathrin disassembly. In this map, we observe density beneath the vertex of the cage that we attribute to bound Hsc70. This density emerges asymmetrically from the clathrin vertex, suggesting preferential binding by Hsc70 for one of the three possible sites at the vertex. Statistical comparison with a map of whole auxilin and clathrin previously published by us reveals the location of statistically significant differences which implicate involvement of clathrin light chains in structural rearrangements which occur after Hsc70 is recruited. Clathrin disassembly assays using light scattering suggest that loss of clathrin light chains reduces the efficiency with which auxilin facilitates this reaction. These data support a regulatory role for clathrin light chains in clathrin disassembly in addition to their established role in regulating clathrin assembly.