Laboratory-based Studies Research Articles

Cardiovascular reactivity during conversations about discrimination is buffered by social support among U.S. Latines

Racial discrimination is conceptualized as an acute and chronic stressor. Like other acute stressors, lab-based studies demonstrate acute effects of discrimination-related stressors on stress-related cardiovascular outcomes, including total cardiac output, blood pressure, and indices of sympathetic and parasympathetic nervous system activity. Critically, it is important to understand how individual and social factors buffer the experience of race-related acute stress. The current study extends existing work by measuring cardiovascular indices of stress during conversations about racial/ethnic discrimination and examines the moderating role of social support. Latine/Hispanic participants (N = 97) talked about personal discrimination experiences with either a close other or a research assistant they had never previously met. Participants in both conditions exhibited cardiovascular reactivity indicative of stress during the conversation. Additionally, patterns of reactivity reflected a more adaptive stress response and recovery profile when participants talked about discriminatory experiences with a close other relative to a stranger (less parasympathetic withdrawal during the stressor and more parasympathetic rebound during recovery). These patterns are consistent with a stress buffering account of social support, which suggests social bonds and community-level support are critical to consider in interventions to mitigate the harms of experiencing discrimination and prevent chronic health disparities.

Studying bats using a One Health lens: bridging the gap between bat virology and disease ecology.

Accumulating data suggest that some bat species host emerging viruses that are highly pathogenic in humans and agricultural animals. Laboratory-based studies have highlighted important adaptations in bat immune systems that allow them to better tolerate viral infections compared to humans. Simultaneously, ecological studies have discovered critical extrinsic factors, such as nutritional stress, that correlate with virus shedding in wild-caught bats. Despite some progress in independently understanding the role of bats as reservoirs of emerging viruses, there remains a significant gap in the molecular understanding of factors that drive virus spillover from bats. Driven by a collective goal of bridging the gap between the fields of bat virology, immunology, and disease ecology, we hosted a satellite symposium at the 2024 American Society for Virology meeting. Bringing together virologists, immunologists, and disease ecologists, we discussed the intrinsic and extrinsic factors such as virus receptor engagement, adaptive immunity, and virus ecology that influence spillover from bat hosts. This article summarizes the topics discussed during the symposium and emphasizes the need for interdisciplinary collaborations and resource sharing.

Low cost and real-time surveillance of enteric infection and diarrhoeal disease using rapid diagnostic tests in Cox’s Bazar, Bangladesh

BackgroundReal-time disease surveillance is an important component of infection control in at-risk populations. However, data on cases or from lab testing is often not available in many low-resource settings. Rapid diagnostic tests (RDT), including immunochromatographic assays, may provide a low cost, expedited source of infection data.MethodsWe conducted a pilot survey-based prevalence mapping study of enteric infection in Camp 24 of the camps for the forcibly displaced Rohingya population from Myanmar in Cox’s Bazar, Bangladesh. We randomly sampled the population and collected and tested stool from under-fives for eight pathogens using RDTs in January–March 2021 and September–October 2021. A Bayesian geospatial statistical model allowing for imperfect sensitivity and specificity of the tests was adapted.ResultsWe collected and tested 396 and 181 stools in the two data collection rounds. Corrected prevalence estimates ranged from 0.5% (Norovirus) to 27.4% (Giardia). Prevalence of Escherichia coli O157, Campylobacter, and Cryptosporidium were predicted to be higher in the high density area of the camp with relatively high probability (70–95%), while Adenovirus, Norovirus, and Rotavirus were lower in the areas with high water chlorination. Clustering of cases of Giardia and Shigella was also observed, although associated with relatively high uncertainty.ConclusionsWith an appropriate correction for diagnostic performance RDTs can be used to generate reliable prevalence estimates, maps, and well-calibrated uncertainty estimates at a significantly lower cost than lab-based studies, providing a useful approach for disease surveillance in these settings.

Plasma ghrelin and risks of sex-specific, site-specific, and early-onset colorectal cancer: A Mendelian randomization analysis.

Epidemiological and laboratory-based studies have provided conflicting evidence for a role of ghrelin in colorectal cancer (CRC) development. We conducted two-sample Mendelian randomization (MR) analyses to evaluate evidence for an association of circulating ghrelin and CRC risk overall and by sex, cancer subsite and age at diagnosis. Genetic instruments proxying plasma total ghrelin levels were obtained from a recent genome-wide association study of 54,219 participants. Summary data for CRC risk were obtained from a recent meta-analysis of several genetic consortia (up to 73,673 cases and 86,854 controls). A two-sample MR approach and several sensitivity analyses were applied. We found no evidence for an association of genetically-predicted plasma total ghrelin levels and CRC risk (0.95, 95% confidence interval: 0.81-1.12; R2 of ghrelin genetic instruments: 4.6%), with similarly null results observed when stratified by sex, anatomical subsite, and for early-onset CRC. Our study suggests that plasma ghrelin levels are unlikely to have a causal relationship with overall, early-onset, and sex- and cancer subsite-stratified CRC risk. This large-scale analysis adds to the growing body of evidence that plasma total ghrelin levels are not associated with CRC risk.

Interactions between antibiotic removal, water matrix characteristics and layered double hydroxide sorbent material

Sorption by layered double hydroxides (LDH) is gaining substantial interest for remediating emerging contaminants, including pharmaceuticals from wastewaters. Findings from a sorbent material performing successfully in lab-based studies using non-environmental (laboratory-sourced) water cannot be assumed to translate to equal performance under environmental downstream applications. However, studies evaluating sorbent material performance for removal of pollutants and understanding material interactions with environmental waters are limited. This study evaluates the removal of the antibiotic amoxicillin (AMX) using a Mg2Al–NO3-LDH sorbent material from laboratory-grade water and wastewater effluent (WWE). AMX is successfully removed (94.53 ± 4.30 % within 24 h) in laboratory-grade water (under batch sorption conditions: 100 μg/L AMX, 0.2 g/L LDH, 20 °C). The comparison of LDH removal performance in laboratory grade and WWE shows a decreased maximum removal of AMX in WWE (13.39 ± 5.53 %). A lower final AMX concentration is observed in the WWE without the presence of LDH, compared to the ‘removal’ experiments in WWE with the presence of LDH, indicating a contribution of non-sorption removal pathways of AMX. This is proposed to be due to the difference in metal concentrations in the WWE with and without LDH present. The presence of LDH is found to decrease concentrations of metal pollutants in WWE, such as Zn concentration decreasing by 85 % over 24 h, changing water characteristics. Overall, this paper reports that an LDH performs differently in laboratory-sourced water and a wastewater effluent. This provides evidence that sorbent material performance needs to be evaluated in complex water matrices to ensure that it is representative of how a sorbent material will perform in an environmental application, which is the end goal of developing such technologies. Finally, good practice recommendations are provided for future lab-scale sorption experiments evaluating the performance of any new sorbent materials for water treatment applications.

Combined effect of polyphosphate kinase and lon protease in Streptomyces coelicolor A3(2) antibiotic production.

The bacterial stringent response is a global regulatory process in which polyphosphate kinase (Ppk) and lon protease are important players. Previous studies have shown that overexpression of the lon gene and deletion of the ppk gene significantly increased actinorhodin production in Streptomyces coelicolor (SCO). In this study, a recombinant SCOΔppk-lon cell, expressing the extra lon gene in Δppk cells, was simulated using a modified in silico (computational) model, ecSco-GEM, and the negative effect of Ppk on actinorhodin production was confirmed. In addition, we identified key enzymes that play a positive role in actinorhodin production. Of these, NADH dehydrogenase/complex-I, beta-ketoacyl-[acyl-carrier-protein] synthase III, glycine cleavage system, and superoxide dismutase were identified as the most significant. By confirming these results with experiments, we have shown that GEMs can be a reliable starting point for in vitro (lab-based) studies of Streptomyces..

Haemolysis overestimates plasma oxidative stress biomarkers in free-ranging roe deer

Quantifying oxidative stress has garnered extensive interest in evolutionary ecology and physiology since proposed as a mediator of life histories. However, while the theoretical framework of oxidative stress ecology is well-supported by laboratory-based studies, results obtained in wild populations on oxidative damage and antioxidant biomarkers have shown inconsistent trends. We propose that red blood cell lysis could be a source of bias affecting measurements of oxidative stress biomarkers, distorting the conclusions drawn from them. Using an experimental approach consisting of enriching plasma from roe deer with lysed red blood cells, we show that the values of commonly used oxidative stress biomarkers linearly increase with the degree of haemolysis – assayed by haemoglobin concentration. This result concerns oxidized proteins (carbonyls) and lipids (TBARS), as well as enzymatic (superoxide dismutase) and non-enzymatic (trolox assay, OXY assay) antioxidant markers. Based on 707 roe deer blood samples collected in the field, we next show that the occurrence of haemolysis in plasma samples is negatively related to age. Finally, we illustrate that considering the variance explained by age-related haemolysis improves explanatory models for inter-individual variability in plasma oxidative stress biomarkers, without substantially altering the estimates of the parameters studied here. Our results raise the question of the veracity of the conclusions if the degree of haemolysis in plasma is not considered in animal models such as roe deer, for which the occurrence and severity of haemolysis vary according to individual characteristics. We recommend measuring and controlling for the degree of haemolysis be considered in future studies that investigate the causes and consequences of oxidative stress in ecophysiological studies.

Temperature dependence of mosquitoes: Comparing mechanistic and machine learning approaches.

Mosquito vectors of pathogens (e.g., Aedes, Anopheles, and Culex spp. which transmit dengue, Zika, chikungunya, West Nile, malaria, and others) are of increasing concern for global public health. These vectors are geographically shifting under climate and other anthropogenic changes. As small-bodied ectotherms, mosquitoes are strongly affected by temperature, which causes unimodal responses in mosquito life history traits (e.g., biting rate, adult mortality rate, mosquito development rate, and probability of egg-to-adult survival) that exhibit upper and lower thermal limits and intermediate thermal optima in laboratory studies. However, it remains unknown how mosquito thermal responses measured in laboratory experiments relate to the realized thermal responses of mosquitoes in the field. To address this gap, we leverage thousands of global mosquito occurrences and geospatial satellite data at high spatial resolution to construct machine-learning based species distribution models, from which vector thermal responses are estimated. We apply methods to restrict models to the relevant mosquito activity season and to conduct ecologically plausible spatial background sampling centered around ecoregions for comparison to mosquito occurrence records. We found that thermal minima estimated from laboratory studies were highly correlated with those from the species distributions (r = 0.87). The thermal optima were less strongly correlated (r = 0.69). For most species, we did not detect thermal maxima from their observed distributions so were unable to compare to laboratory-based estimates. The results suggest that laboratory studies have the potential to be highly transportable to predicting lower thermal limits and thermal optima of mosquitoes in the field. At the same time, lab-based models likely capture physiological limits on mosquito persistence at high temperatures that are not apparent from field-based observational studies but may critically determine mosquito responses to climate warming. Our results indicate that lab-based and field-based studies are highly complementary; performing the analyses in concert can help to more comprehensively understand vector response to climate change.

Sensitivity of Alabama Freshwater Gastropod Species to Nickel Exposure.

Snails are effective bioindicators due to their prolific distribution, high level of endemism, and capacity to accumulate contaminants. Freshwater snails have unique ecological niches which are imperiled by land-use change and the introduction of hazardous chemicals. To assess how environmental alterations affect gastropods, lab-based studies are needed to characterize the toxicity of specific stressors. This can help guide policy decisions and remediation efforts. The aim of this research was to characterize acute toxicity of nickel (Ni) on endemic snails (Somatogyrus georgianus [Walker, 1904], Elimia cahawbensis [Lea, 1861], and Elimia spp.) and measure the accumulation of Ni and mineral elements including calcium (Ca), magnesium, potassium, and sodium (Na). Snails were exposed to six concentrations (25-800 µg/L) of Ni for 96 h. Among the studied snail species, E. cahawbensis was the most sensitive to Ni, with the lowest lethal concentration where 50% of the organisms died (LC50) at 88.88 µg/L Ni after 96 h. The LC50 at 96 h for S. georgianus was 167.78 µg/L Ni, and 393.13 μg/L Ni for Elimia spp. Except for Elimia spp., mortality of the other two snail species corresponded to the whole-body uptake of Ni. Nickel exposure also influenced Ca and Na uptake for Elimia spp. All three endemic species are potential candidate species for evaluating localized effects of human activities, and the present study provides a first step in characterizing how snails would be affected by environmental alterations. More research could further characterize potential effects of other human stressors on these endemic snail species. Future research into subindividual responses and routes of exposure can further elucidate variations in species sensitivity. Environ Toxicol Chem 2024;00:1-11. © 2024 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Validating Silent Gesture Lab Studies in a Naturally Emerging Sign Language:How Order is Used to Describe Intensional Versus Extensional Events in Nicaraguan Sign Language.

Languages are neither designed in classrooms nor drawn from dictionaries-they are products of human minds and human interactions. However, it is challenging to understand how structure grows in these circumstances because generations of use and transmission shape and reshape the structure of the languages themselves. Laboratory studies on language emergence investigate the origins of language structure by requiring participants, prevented from using their own natural language(s), to create a novel communication system and then transmit it to others.Because the participants in these lab studies are already speakers of a language, it is easy to question the relevance of lab-based findings to the creation of natural language systems. Here, we take the findings from a lab-based language emergence paradigm and test whether the same pattern is also found in a new natural language: Nicaraguan Sign Language. We find evidence that signers of Nicaraguan Sign Language may show the same biases seen in lab-based language emergence studies: (1) they appear to condition word order based on the semantic dimension of intensionality and extensionality, and (2) they adjust this conditioning to satisfy language-internal order constraints. Our study adds to the small, but growing literature testing the relevance of lab-based studies to natural language birth, and provides convincing evidence that the biases seen in the lab play a role in shaping a brand new language.

Disturbances in Electrodermal Activity Recordings Due to Different Noises in the Environment.

Electrodermal activity (EDA) is a widely used psychophysiological measurement in laboratory-based studies. In recent times, these measurements have seen a transfer from the laboratory to wearable devices due to the simplicity of EDA measurement as well as modern electronics. However, proper conditions for EDA measurement are recommended once wearable devices are used, and the ambient conditions may influence such measurements. It is not completely known how different types of ambient noise impact EDA measurement and how this translates to wearable EDA measurement. Therefore, this study explored the effects of various noise disturbances on the generation of EDA responses using a system for the simultaneous recording of all measures of EDA, i.e., skin conductance responses (SCRs), skin susceptance responses (SSRs), and skin potential responses (SPRs), at the same skin site. The SCRs, SSRs, and SPRs due to five types of noise stimuli at different sound pressure levels (70, 75, 80, 85, and 90 dB) were measured from 40 participants. The obtained results showed that EDA responses were generated at all levels and that the EDA response magnitudes were significantly (p < 0.001) influenced by the increasing noise levels. Different types of environmental noise may elicit EDA responses and influence wearable recordings outside the laboratory, where such noises are more likely than in standardized laboratory tests. Depending on the application, it is recommended to prevent these types of unwanted variation, presenting a challenge for the quality of wearable EDA measurement in real-world conditions. Future developments to shorten the quality gap between standardized laboratory-based and wearable EDA measurements may include adding microphone sensors and algorithms to detect, classify, and process the noise-related EDA.

Nature should be the model for microbial sciences.

Until recently, microbiologists have relied on cultures to understand the microbial world. As a result, model organisms have been the focus of research into understanding Bacteria and Archaea at a molecular level. Diversity surveys and metagenomic sequencing have revealed that these model species are often present in low abundance in the environment; instead, there are microbial taxa that are cosmopolitan in nature. Due to the numerical dominance of these microorganisms and the size of their habitats, these lineages comprise mind-boggling population sizes upward of 1028 cells on the planet. Many of these dominant groups have cultured representatives and have been shown to be involved in mediating key processes in nature. Given their importance and the increasing need to understand changes due to climate change, we propose that members of Nitrosophaerota (Nitrosopumilus maritimus), SAR11 (Pelagibacter ubique), Hadesarchaeia, Bathyarchaeia, and others become models in the future. Abundance should not be the only measure of a good model system; there are other organisms that are well suited to advance our understanding of ecology and evolution. For example, the most well-studied symbiotic bacteria, like Buchnera, Aliivibrio, and Rhizobium, should be models for understanding host-associations. Also, there are organisms that hold new insights into major transitions in the evolution of life on the planet like the Asgard Archaea (Heimdallarchaeia). Innovations in a variety of in situ techniques have enabled us to circumvent culturing when studying everything from genetics to physiology. Our deepest understanding of microbiology and its impact on the planet will come from studying these microbes in nature. Laboratory-based studies must be grounded in nature, not the other way around.

Clinical characteristics, laboratory features and genetic profile of hemoglobin E (HBB:c.79 G > A)/β (nucleotide -28 A > G) (HBB:c.-78 A > G) -thalassemia subjects identified from community- and hospital-recruited cohorts

Despite several existing laboratory-based studies of hemoglobin (Hb) E (HBB:c.79 G > A)/ β (nucleotide (NT) -28 A > G) (HBB:c.-78 A > G) -thalassemia, no reports have ever provided clinical severity information as well as dependency of blood transfusion. Previously, a comparative study of community- and hospital-recruited Hb E/β-thalassemia subjects was conducted in the lower northern Thailand between June 2020 and December 2021. A mobile medical team visited each community hospital on-site, collecting clinical severity parameters, and conducting Hb and DNA analyses. The control included Hb E/β-thalassemia patients undergoing transfusions. Subgroup study of adult Hb E/β (NT -28 A > G) -thalassemia subjects was subsequently conducted. Additional pediatric individuals were recruited from prenatal diagnosis databases. Twenty adult and nine pediatric subjects were enrolled; all were classified as having mild disease severity. Twenty-two individuals (75.9 %) were asymptomatic. Six adults (20.7 %) required blood transfusion. The mean Hb level of subjects without transfusion (23 [79.3 %]) was 10.77 ± 1.10 g/dL. Hb analysis revealed a distinct EFA pattern with low Hb F fraction. The positive impact of genetic modifiers could not be statistically demonstrated except rs7482144-XmnI. These findings could provide essential information for parents carrying fetuses with Hb E/β (NT -28 A > G) -thalassemia.

Experimental and Numerical Simulation Study on CO2-Assisted Steamflooding in Ultraheavy Oil Reservoirs

Summary Certain ultraheavy oil reservoirs with depths approaching 1000 m feature wide well spacing. After cyclic steam stimulation (CSS), cold oil zones with high residual oil saturation exist between wells. This leads to a high oil saturation at the steam front during the subsequent steamflooding process, which in turn results in a high injection pressure. The simultaneous injection of CO2 and steam into the formation can optimize formation pressure and enhance steam utilization efficiency. A majority of laboratory-based experimental studies have reported favorable outcomes with CO2-assisted steamflooding. However, some field tests of CO2-assisted steamflooding have encountered severe steam channeling problems, resulting in oil recovery and an oil/steam ratio below the expected level. Consequently, this study uses an ultraheavy oil reservoir as a case study and integrates physical simulation with numerical simulation to investigate the impact of CO2-assisted steamflooding on enhanced oil recovery in ultraheavy oil reservoirs. The findings suggest that the beneficial effect of CO2 in reducing oil viscosity and injection pressure plays a significant role in models with smaller thickness, thereby improving oil production rate and recovery factor. However, as the thickness of the model increases, the adverse effect of CO2 exacerbating steam channeling becomes increasingly evident, leading to a decline in the oil recovery factor and a longer duration to reach the maximum recovery factor. Therefore, in field applications, it is essential to consider adjusting the CO2 injection method or using thermosetting plugging agents to achieve superior results.

TEG® 6s coagulation testing with a novel heparin neutralization cartridge: Technical validation and determination of normal reference ranges.

We sought to establish normal reference ranges (NRRs) for a novel TEG 6s cartridge (TEG 6s Citrated: K, KH, RTH, FFH [Global Hemostasis]) (Haemonetics Corporation, Boston, MA, US). Healthy volunteers (≥18 years of age) included in this single-arm study provided single samples of whole blood. Primary end points included TEG parameters in the citrated kaolin (CK), CK with heparinase (CKH), RapidTEG with heparinase (CRTH), and functional fibrinogen with heparinase (CFFH) assays. Evaluable data were contributed by 164 volunteers (48.8% female; 62% White/Caucasian). The following NRRs were established: CK maximum amplitude (MA), 51.0 to 67.6mm; CKH-MA, 51.8 to 67.9mm; CRTH-MA, 53.0 to 68.9mm; CFFH-MA, 15.3 to 34.4mm; CK reaction time, 5.0 to 9.1 minutes; CKH reaction time, 4.9 to 9.4 minutes; CKH lysis 30 minutes after MA, 0% to 3.2%. Duplicate measurements demonstrated high reproducibility. CFFH-MA correlated with Clauss fibrinogen concentration (Pearson correlation coefficient, 0.74). Laboratory-based studies demonstrated maintenance of the relationship between CFFH-MA and fibrinogen up to 1344mg/dL (hyperfibrinogenemic samples) and acceptability of heparin neutralization up to concentrations of low molecular weight and unfractionated heparin of 1.3 IU/mL and 5 IU/mL, respectively. This study established NRRs for the Global Hemostasis cartridge and serves as a proof of concept for the validity of results obtained using this cartridge.

The Ecology of Human Sleep (EcoSleep) Cohort Study: Protocol for a longitudinal repeated measurement burst design study to assess the relationship between sleep determinants and outcomes under real-world conditions across time of year.

The interplay of daily life factors, including mood, physical activity, or light exposure, influences sleep architecture and quality. Laboratory-based studies often isolate these determinants to establish causality, thereby sacrificing ecological validity. Furthermore, little is known about time-of-year changes in sleep and circadian-related variables at high resolution, including the magnitude of individual change across time of year under real-world conditions. The Ecology of Human Sleep (EcoSleep) cohort study will investigate the combined impact of sleep determinants on individuals' daily sleep episodes to elucidate which waking events modify sleep patterns. A second goal is to describe high-resolution individual sleep and circadian-related changes across the year to understand intra- and inter-individual variability. This study is a prospective cohort study with a measurement-burst design. Healthy adults aged 18-35 years (N = 12) will be enrolled for 12 months. Participants will continuously wear actimeters and pendant-attached light loggers. A subgroup will also measure interstitial fluid glucose levels (six paticipants). Every 4 weeks, all participants will undergo three consecutive measurement days of four ecological momentary assessments each day ('bursts') to sample sleep determinants during wake. Participants will also continuously wear temperature loggers (iButtons) during the bursts. Body weight will be captured before and after the bursts in the laboratory. The bursts will be separated by two at-home electroencephalogram recordings each night. Circadian phase and amplitude will be estimated during the bursts from hair follicles, and habitual melatonin onset will be derived through saliva sampling. Environmental parameters (bedroom temperature, humidity, and air pressure) will be recorded continuously.

Reduced heart rate variability is related to fluctuations in psychological stress levels in daily life.

Laboratory-based studies have shown that psychological stress caused by response to various stressors triggers acute changes in the cardiovascular system. A better understanding is needed of the emerging evidence on temporal associations between psychological stress and cardiovascular responses in natural settings. This study examined the association of psychological stress and heart rate variability (HRV) in daily life, at high resolution over 2weeks, taking the effect of physical activity into account. Participants (n=34) completed ecological momentary assessments (EMA) 6 times per day, reporting levels of perceived stress, low-arousal negative affect (LNA), and high-arousal negative affect. Chest-mounted heart-rate monitors were worn to assess HRV. Multilevel models were used to examine the association between psychological stress levels and preceding/subsequent HRV. Reduced time domain HRV measures (mean and standard deviation of R-wave to R-wave intervals) during the prior hour predicted higher levels of perceived stress. Frequency domain HRV measures higher low to high frequency (LF/HF) and lower HF to total power (HF nu) ratios during the preceding 10min predicted higher perceived stress levels, suggesting the dominance of sympathetic nervous system activity. EMA reports of higher perceived stress levels were associated with reduced time domain HRV measures during the following 10min. On the other hand, higher LNA were related to increased HRV measures, such as lower LF/HF and higher HF nu during the following hour.The dynamic associations observed may have therapeutic implications for 'just-in-time' interventions in the management of daily stress and cardiovascular health.

P-241 The in vivo human uterine pH and uterine fluid composition differs from pH and composition of clinically used in vitro preimplantation embryo culture media

Abstract Study question To study the pH and uterine fluid composition in the human uterus three days after a positive LH test or ovum pick-up. Summary answer The uterine pH three days after a positive LH test or ovum pick-up was 6.8. Concentrations of 37 components were determined in uterine fluid. What is known already In assisted reproductive technologies (ART), the in vitro culture of human preimplantation embryos is known to play a crucial role in the success of In Vitro Fertilization (IVF) treatments. It affects live birth rates and child outcomes such as birth weight. Numerous commercial embryo culture media are routinely used in clinical practice worldwide, but their composition is primarily based on laboratory-based clinical insights and experimental studies with animal models. Studies on the natural human preimplantation embryo environment during the physiologically relevant time of the menstrual cycle are limited. Study design, size, duration A cross sectional clinical study was conducted to study the uterine pH and the composition of human uterine fluid. The uterine pH was measured in 53 women on the third day after LH surge (N = 46) or ovum pickup (N = 7), as that time in the menstrual cycle is associated with endometrial receptivity for embryo implantation. Twenty-two samples of aspirated uterine fluid, that were collected at the same time, were analyzed for the concentrations of thirty-seven components. Participants/materials, setting, methods Healthy women of reproductive age with normal functional uterine anatomy were included. Uterine pH was determined using pH probe inserted through outer sheath of an Embryo Transfer (ET) catheter at the lithotomy position. Uterine fluid was then aspirated using a syringe connected to outer sheath of this ET catheter. Collected samples were analyzed using a Cobas 8000 chemistry analyser and ultra-performance liquid chromatography-tandem mass spectrometry. Main results and the role of chance The mean pH in the uterine cavity on the third day after a positive LH test (6.75 ± 0.22) or ovum pick-up (6.82 ± 0.18) was clearly lower than the pH used in routine clinical practice for preimplantation embryo culture (pH 7.3 ± 0.1). Calcium, phosphate, lactate(L), pyruvate, albumin and 21 amino acids were present at different concentrations in human uterine fluid compared to most commonly used preimplantation embryo culture media. Immunoglobulins, citrulline, ornithine and uric acid were present in uterine fluid, but not in clinically used culture media. Limitations, reasons for caution As the uterine cavity is only one part of the reproductive tract, our measurements do not fully represent the complete in vivo environment of preimplantation embryo development. We only studied 37 components, recognizing that uterine fluid likely contains additional components. Wider implications of the findings The observed differences between the uterine pH and the composition of uterine fluid and the pH and composition of preimplantation embryo culture media used in routine clinical practice could be a starting point to further optimize in vitro embryo culture in ART treatments. Trial registration number Not applicable

Field- and laboratory-based studies on correlates of Chlamydia trachomatis transmission by Musca sorbens: Determinants of fly-eye contact and investigations into fly carriage of elementary bodies.

Musca sorbens (Diptera: Muscidae) flies are thought to be vectors of the blinding eye disease trachoma, carrying the bacterium Chlamydia trachomatis (Ct) between the eyes of individuals. While their role as vectors has been convincingly demonstrated via randomised controlled trials in The Gambia, studies of fly-borne trachoma transmission remain scant and as such our understanding of their ability to transmit Ct remains poor. We examined fly-eye contact and caught eye-seeking flies from 494 individuals (79% aged ≤9 years) in Oromia, Ethiopia. Ct-carrying flies (harbouring Ct DNA) were found to cluster spatially in and nearby to households in which at least one resident had Ct infection. Fly-eye contact was positively associated with the presence of trachoma (disease), lower human body weight and increased human body temperature. Studies of laboratory-reared M. sorbens indicated that Ct is found both externally and internally following feeds on Ct culture, with scanning electron microscopy revealing how Ct bodies can cling to fly hairs (setae). Testing for Ct on field-caught M. sorbens found fly 'bodies' (thorax, wings and abdomen) to consistently test positive for Ct while legs and heads were infrequently Ct-positive. These studies strongly support the role of M. sorbens as vectors of trachoma and highlight the need for improved understanding of fly-borne trachoma transmission dynamics and vector competence.

Iron Chelation in Soil: Scalable Biotechnology for Accelerating Carbon Dioxide Removal by Enhanced Rock Weathering.

Enhanced rock weathering (EW) is an emerging atmospheric carbon dioxide removal (CDR) strategy being scaled up by the commercial sector. Here, we combine multiomics analyses of belowground microbiomes, laboratory-based dissolution studies, and incubation investigations of soils from field EW trials to build the case for manipulating iron chelators in soil to increase EW efficiency and lower costs. Microbial siderophores are high-affinity, highly selective iron (Fe) chelators that enhance the uptake of Fe from soil minerals into cells. Applying RNA-seq metatranscriptomics and shotgun metagenomics to soils and basalt grains from EW field trials revealed that microbial communities on basalt grains significantly upregulate siderophore biosynthesis gene expression relative to microbiomes of the surrounding soil. Separate in vitro laboratory incubation studies showed that micromolar solutions of siderophores and high-affinity synthetic chelator (ethylenediamine-N,N'-bis-2-hydroxyphenylacetic acid, EDDHA) accelerate EW to increase CDR rates. Building on these findings, we develop a potential biotechnology pathway for accelerating EW using the synthetic Fe-chelator EDDHA that is commonly used in agronomy to alleviate the Fe deficiency in high pH soils. Incubation of EW field trial soils with potassium-EDDHA solutions increased potential CDR rates by up to 2.5-fold by promoting the abiotic dissolution of basalt and upregulating microbial siderophore production to further accelerate weathering reactions. Moreover, EDDHA may alleviate potential Fe limitation of crops due to rising soil pH with EW over time. Initial cost-benefit analysis suggests potassium-EDDHA could lower EW-CDR costs by up to U.S. $77 t CO2 ha-1 to improve EW's competitiveness relative to other CDR strategies.