Transcriptomic analysis of shell repair and biomineralization in the blue mussel, Mytilus edulis.

Biomineralization by molluscs involves regulated deposition of calcium carbonate crystals within a protein framework to produce complex biocomposite structures. Effective biomineralization is a key trait for aquaculture, and animal resilience under future climate change. While many enzymes and structural proteins have been identified from the shell and in mantle tissue, understanding biomieralization is impeded by a lack of fundamental knowledge of the genes and pathways involved. In adult bivalves, shells are secreted by the mantle tissue during growth, maintenance and repair, with the repair process, in particular, amenable to experimental dissection at the transcriptomic level in individual animals

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Kompensationsvermögen von Mytilus edulis gegenüber mechanischem Stress und erhöhtem pCO2 - kombinierte transkriptomische, proteomische und physiologische Analysen

The CO2 content of the atmosphere is increasing since the onset of the industrial revolution. As a result, CO2 is taken up by the oceans, which leads to decreases in seawater pH and carbonate ion concentration [CO32-]. As calcifying organisms use CO32- to construct their skeletons, they are suggested to be particularly impaired by ocean acidification. In this study, the basic molecular mechanisms underlying biomineralization of the blue mussel Mytilus edulis, and its acclimation potential towards elevated pCO2 in general and regarding biomineralization in particular were determined. For these experiments, a population from Kiel Fjord was used, which is already seasonally exposed to elevated pCO2 values that are predicted for the near future. First, separate transcriptomes were generated from the central and pallial/marginal mantle, the tissues responsible for biomineralization. For this purpose, animals that have been incubated for eight weeks at 500 µatm (control) and 3700 µatm pCO2 were used. Analyses revealed only minor global changes as a result of elevated pCO2

Responsiveness of Mytilus edulis towards mechanical stress and elevated pCO2 - combined transcriptomic, proteomic and physiological analyses

The CO2 content of the atmosphere is increasing since the onset of the industrial revolution. As a result, CO2 is taken up by the oceans, which leads to decreases in seawater pH and carbonate ion concentration [CO32-]. As calcifying organisms use CO32- to construct their skeletons, they are suggested to be particularly impaired by ocean acidification. In this study, the basic molecular mechanisms underlying biomineralization of the blue mussel Mytilus edulis, and its acclimation potential towards elevated pCO2 in general and regarding biomineralization in particular were determined. For these experiments, a population from Kiel Fjord was used, which is already seasonally exposed to elevated pCO2 values that are predicted for the near future. First, separate transcriptomes were generated from the central and pallial/marginal mantle, the tissues responsible for biomineralization. For this purpose, animals that have been incubated for eight weeks at 500 µatm (control) and 3700 µatm pCO2 were used. Analyses revealed only minor global changes as a result of elevated pCO2

Feasibility of Video Consultation for Preterm Neurodevelopmental Follow-up Care During the COVID-19 Pandemic: Cohort Study

BackgroundDuring the COVID-19 pandemic, parents of infants born very preterm or at risk were exceptionally worried about being infected. The only means of protection during the onset of the pandemic was social distancing. Video consultations for neurodevelopmental follow-up care were offered as an alternative way to stay in contact with patients and their families, to provide expert support, and to monitor and assess children’s development. ObjectiveTo assess the feasibility of and family satisfaction with video consultations, interviews were conducted after video and in-person consultations. MethodsAn interview with 28 questions was created to evaluate parental satisfaction with the consultations (eg, their confidentiality and the children’s behavior). A total of 93 interviews with parents were conducted between March 2020 and February 2021 and compared (58 after video consultations and 35 after in-person consultations). The interviews were conducted at the end of the consultations by a trained professional. The video consultations were conducted using a certified platform created by Zava Sprechstunde Online, maintaining data protection with end-to-end encryption. Follow-up consultations (video or in-person) were performed at corrected ages of 3, 6, and 12 months as well as 2, 3, 4, and 5 years. The rate of total follow-up appointments attended during the survey period was evaluated and compared with the previous year. ResultsThere were no significant differences between the video and in-person consultation groups in satisfaction, attitudes on the confidentiality of the consultation, or discussion of private and sensitive information. Following video consultations, parents were significantly more likely to report that they were avoiding contact with medical professionals during the pandemic (P=.045; Shapiro-Wilk W=1094.5, Cohen d=–0.1782146) than the in-person consultation group. Parents in the video-consultation group stated that performing a guided examination on their child was comfortable and helped them understand their child’s development. In fact, they agreed to take advantage of future video consultations. The rate of total follow-up appointments increased compared to the previous year. Between March 2019 and February 2020, 782 of 984 (79.5%) children born at Essen University Hospital attended a follow-up appointment. During the survey period, between March 2020 and February 2021, a total of 788 of 1086 children (73%) attended a follow-up appointment, of which 117 (14.9%) were video consultations. ConclusionsThe feasibility of attending video consultations for follow-up care of very preterm or at-risk infants and parental satisfaction with these consultations were as high as for in-person consultations. Parents rated video consultations as being as confidential as in-person appointments. Telemedicine can be offered as an equivalent alternative to in-person consultations and is particularly useful under certain circumstances, such as for very sick children who require assistive devices or respiratory support and oxygen or for those living a long distance away

Impacts of seawater acidification on mantle gene expression patterns of the Baltic Sea blue mussel: implications for shell formation and energy metabolism, link to supplementary material

Marine organisms have to cope with increasing CO2 partial pressures and decreasing pH in the oceans. We elucidated the impacts of an 8-week acclimation period to four seawater pCO2 treatments (39, 113, 243 and 405 Pa/385, 1,120, 2,400 and 4,000 µatm) on mantle gene expression patterns in the blue mussel Mytilus edulis from the Baltic Sea. Based on the M. edulis mantle tissue transcriptome, the expression of several genes involved in metabolism, calcification and stress responses was assessed in the outer (marginal and pallial zone) and the inner mantle tissues (central zone) using quantitative real-time PCR. The expression of genes involved in energy and protein metabolism (F-ATPase, hexokinase and elongation factor alpha) was strongly affected by acclimation to moderately elevated CO2 partial pressures. Expression of a chitinase, potentially important for the calcification process, was strongly depressed (maximum ninefold), correlating with a linear decrease in shell growth observed in the experimental animals. Interestingly, shell matrix protein candidate genes were less affected by CO2 in both tissues. A compensatory process toward enhanced shell protection is indicated by a massive increase in the expression of tyrosinase, a gene involved in periostracum formation (maximum 220-fold). Using correlation matrices and a force-directed layout network graph, we were able to uncover possible underlying regulatory networks and the connections between different pathways, thereby providing a molecular basis of observed changes in animal physiology in response to ocean acidification

A shell regeneration assay to identify biomineralization candidate genes in mytilid mussels

Biomineralization processes in bivalve molluscs are still poorly understood. Here we provide an analysis of specifically expressed sequences from a mantle transcriptome of the blue mussel, Mytilus edulis. We then developed a novel, integrative shell injury assay to test, whether biomineralization candidate genes highly expressed in marginal and pallial mantle could be induced in central mantle tissue underlying the damaged shell areas. This experimental approach makes it possible to identify gene products that control the chemical micro-environment during calcification as well as organic matrix components. This is unlike existing methodological approaches that work retroactively to characterize calcification relevant molecules and are just able to examine organic matrix components that are present in completed shells. In our assay an orthogonal array of nine 1 mm holes was drilled into the left valve, and mussels were suspended in net cages for 20, 29 and 36 days to regenerate. Structural observations using stereo-microscopy, SEM and Raman spectroscopy revealed organic sheet synthesis (day 20) as the first step of shell-repair followed by the deposition of calcite crystals (days 20 and 29) and aragonite tablets (day 36). The regeneration period was characterized by time-dependent shifts in gene expression in left central mantle tissue underlying the injured shell, (i) increased expression of two tyrosinase isoforms (TYR3: 29-fold and TYR6: 5-fold) at day 20 with a decline thereafter, (ii) an increase in expression of a gene encoding a nacrein-like protein (max. 100-fold) on day 29. The expression of an acidic Asp-Ser-rich protein was enhanced during the entire regeneration process. This proof-of-principle study demonstrates that genes that are specifically expressed in pallial and marginal mantle tissue can be induced (4 out of 10 genes) in central mantle following experimental injury of the overlying shell. Our findings suggest that regeneration assays can be used systematically to better characterize gene products that are essential for distinct phases of the shell formation process, particularly those that are not incorporated into the organic shell matrix