160 research outputs found

    Biological functions at high pressure: transcriptome response of Shewanella oneidensis MR-1 to hydrostatic pressure relevant to Titan and other icy ocean worlds

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    High hydrostatic pressure (HHP) is a key driver of life's evolution and diversification on Earth. Icy moons such as Titan, Europa, and Enceladus harbor potentially habitable high-pressure environments within their subsurface oceans. Titan, in particular, is modeled to have subsurface ocean pressures ≥ 150 MPa, which are above the highest pressures known to support life on Earth in natural ecosystems. Piezophiles are organisms that grow optimally at pressures higher than atmospheric (0.1 MPa) pressure and have specialized adaptations to the physical constraints of high-pressure environments – up to ~110 MPa at Challenger Deep, the highest pressure deep-sea habitat explored. While non-piezophilic microorganisms have been shown to survive short exposures at Titan relevant pressures, the mechanisms of their survival under such conditions remain largely unelucidated. To better understand these mechanisms, we have conducted a study of gene expression for Shewanella oneidensis MR-1 using a high-pressure experimental culturing system. MR-1 was subjected to short-term (15 min) and long-term (2 h) HHP of 158 MPa, a value consistent with pressures expected near the top of Titan's subsurface ocean. We show that MR-1 is metabolically active in situ at HHP and is capable of viable growth following 2 h exposure to 158 MPa, with minimal pressure training beforehand. We further find that MR-1 regulates 264 genes in response to short-term HHP, the majority of which are upregulated. Adaptations include upregulation of the genes argA, argB, argC, and argF involved in arginine biosynthesis and regulation of genes involved in membrane reconfiguration. MR-1 also utilizes stress response adaptations common to other environmental extremes such as genes encoding for the cold-shock protein CspG and antioxidant defense related genes. This study suggests Titan's ocean pressures may not limit life, as microorganisms could employ adaptations akin to those demonstrated by terrestrial organisms

    Hepatocyte and keratinocyte growth factors and their receptors in human lung emphysema

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    BACKGROUND: Hepatocyte and keratinocyte growth factors are key growth factors in the process of alveolar repair. We hypothesized that excessive alveolar destruction observed in lung emphysema involves impaired expression of hepatocyte and keratinocyte growth factors or their respective receptors, c-met and keratinocyte growth factor receptor. The aim of our study was to compare the expression of hepatocyte and keratinocyte growth factors and their receptors in lung samples from 3 groups of patients: emphysema; smokers without emphysema and non-smokers without emphysema. METHODS: Hepatocyte and keratinocyte growth factor proteins were analysed by immunoassay and western blot; mRNA expression was measured by real time quantitative polymerase chain reaction. RESULTS: Hepatocyte and keratinocyte growth factors, c-met and keratinocyte growth factor receptor mRNA levels were similar in emphysema and non-emphysema patients. Hepatocyte growth factor mRNA correlated negatively with FEV1 and the FEV1/FVC ratio both in emphysema patients and in smokers with or without emphysema. Hepatocyte and keratinocyte growth factor protein concentrations were similar in all patients' groups. CONCLUSION: The expression of hepatocyte and keratinocyte growth factors and their receptors is preserved in patients with lung emphysema as compared to patients without emphysema. Hepatocyte growth factor mRNA correlates with the severity of airflow obstruction in smokers

    Callous-unemotional traits moderate the relation between prenatal testosterone (2D:4D) and externalising behaviours in children

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    Children who exhibit callous-unemotional (CU) traits are identified as developing particularly severe forms of externalising behaviours (EB). A number of risk factors have been identified in the development of CU traits, including biological, physiological, and genetic factors. However, prenatal testosterone (PT) remains un-investigated, yet could signal fetal programming of a combination of CU/EB. Using the 2D:4D digit ratio, the current study examined whether CU traits moderated the relationship between PT and EB. Hand scans were obtained from 79 children aged between 5 and 6 years old whose parents completed the parent report ICU (Inventory of Callous Unemotional Traits) and SDQ (Strengths and Difficulties Questionnaire). CU traits were found to moderate the relationship between PT and EB so that children who were exposed to increased PT and were higher in CU traits exhibited more EB. Findings emphasize the importance of recognising that vulnerability for EB that is accompanied by callousness may arise before birth

    Adaptations Made to Pediatric Consultation-Liaison Psychiatry Service Delivery During the Early Months of the COVID-19 Pandemic: A North American Multisite Survey.

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    BackgroundThe COVID-19 pandemic led to rapid changes in clinical service delivery across hospital systems nationally. Local realities and resources were key driving factors impacting workflow changes, including for pediatric consultation-liaison psychiatry service (PCLPS) providers.ObjectiveThis study aims to describe the early changes implemented by 22 PCLPSs from the United States and Canada during the COVID-19 pandemic. Understanding similarities and differences in adaptations made to PCLPS care delivery can inform best practices and future models of care.MethodsA 20-point survey relating to PCLPS changes during the COVID-19 pandemic was sent to professional listservs. Baseline hospital demographics, hospital and PCLPS workflow changes, and PCLPS experience were collected from March 20 to April 28, 2020, and from August 18 to September 10, 2020. Qualitative data were collected from responding sites. An exploratory thematic analysis approach was used to analyze the qualitative data that were not dependent on predetermined coding themes. Descriptive statistics were calculated using Microsoft Excel.ResultsTwenty-two academic hospitals in the United States and Canada responded to the survey, with an average of 303 beds/hospital. Most respondents (18/22) were children's hospitals. Despite differences in regional impact of COVID-19 and resource availability, there was significant overlap in respondent experiences. Restricted visitation to one caregiver, use of virtual rounding, ongoing trainee involvement, and an overall low number of COVID-positive pediatric patients were common. While there was variability in PCLPS care delivery occurring virtually versus in person, all respondents maintained some level of on-site presence. Technological limitations and pediatric provider preference led to increased on-site presence.ConclusionsTo our knowledge, this is the first multicenter study exploring pandemic-related PCLPS changes in North America. Findings of this study demonstrate that PCLPSs rapidly adapted to COVID-19 realities. Common themes emerged that may serve as a model for future practice. However, important gaps in understanding their effectiveness and acceptability need to be addressed. This multisite survey highlights the importance of establishing consensus through national professional organizations to inform provider and hospital practices

    Genomic analysis of the causative agents of coccidiosis in domestic chickens

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    Global production of chickens has trebled in the past two decades and they are now the most important source of dietary animal protein worldwide. Chickens are subject to many infectious diseases that reduce their performance and productivity. Coccidiosis, caused by apicomplexan protozoa of the genus Eimeria, is one of the most important poultry diseases. Understanding the biology of Eimeria parasites underpins development of new drugs and vaccines needed to improve global food security. We have produced annotated genome sequences of all seven species of Eimeria that infect domestic chickens, which reveal the full extent of previously described repeat-rich and repeat-poor regions and show that these parasites possess the most repeat-rich proteomes ever described. Furthermore, while no other apicomplexan has been found to possess retrotransposons, Eimeria is home to a family of chromoviruses. Analysis of Eimeria genes involved in basic biology and host-parasite interaction highlights adaptations to a relatively simple developmental life cycle and a complex array of co-expressed surface proteins involved in host cell binding

    Potential for non-combustible nicotine products to reduce socioeconomic inequalities in smoking: a systematic review and synthesis of best available evidence

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    While some experts have emphasised the potential for e-cigarettes to facilitate cessation among smokers with low socioeconomic status (SES), there is limited evidence of their likely equity impact. We assessed the potential for electronic cigarettes and other non-combustible nicotine-containing products (NCNPs) to reduce inequalities in smoking by systematically reviewing evidence on their use by SES in countries at stage IV of the cigarette epidemic
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