Recursive construction of perfect DNA molecules from imperfect oligonucleotides

Making faultless complex objects from potentially faulty building blocks is a fundamental challenge in computer engineering, nanotechnology and synthetic biology. Here, we show for the first time how recursion can be used to address this challenge and demonstrate a recursive procedure that constructs error-free DNA molecules and their libraries from error-prone oligonucleotides. Divide and Conquer (D&C), the quintessential recursive problem-solving technique, is applied in silico to divide the target DNA sequence into overlapping oligonucleotides short enough to be synthesized directly, albeit with errors; error-prone oligonucleotides are recursively combined in vitro, forming error-prone DNA molecules; error-free fragments of these molecules are then identified, extracted and used as new, typically longer and more accurate, inputs to another iteration of the recursive construction procedure; the entire process repeats until an error-free target molecule is formed. Our recursive construction procedure surpasses existing methods for de novo DNA synthesis in speed, precision, amenability to automation, ease of combining synthetic and natural DNA fragments, and ability to construct designer DNA libraries. It thus provides a novel and robust foundation for the design and construction of synthetic biological molecules and organisms

EuCARE-POSTCOVID Study: a multicentre cohort study on long-term post-COVID-19 manifestations

BACKGROUND: Post-COVID-19 condition refers to persistent or new onset symptoms occurring three months after acute COVID-19, which are unrelated to alternative diagnoses. Symptoms include fatigue, breathlessness, palpitations, pain, concentration difficulties ("brain fog"), sleep disorders, and anxiety/depression. The prevalence of post-COVID-19 condition ranges widely across studies, affecting 10-20% of patients and reaching 50-60% in certain cohorts, while the associated risk factors remain poorly understood. METHODS: This multicentre cohort study, both retrospective and prospective, aims to assess the incidence and risk factors of post-COVID-19 condition in a cohort of recovered patients. Secondary objectives include evaluating the association between circulating SARS-CoV-2 variants and the risk of post-COVID-19 condition, as well as assessing long-term residual organ damage (lung, heart, central nervous system, peripheral nervous system) in relation to patient characteristics and virology (variant and viral load during the acute phase). Participants will include hospitalised and outpatient COVID-19 patients diagnosed between 01/03/2020 and 01/02/2025 from 8 participating centres. A control group will consist of hospitalised patients with respiratory infections other than COVID-19 during the same period. Patients will be followed up at the post-COVID-19 clinic of each centre at 2-3, 6-9, and 12-15 months after clinical recovery. Routine blood exams will be conducted, and patients will complete questionnaires to assess persisting symptoms, fatigue, dyspnoea, quality of life, disability, anxiety and depression, and post-traumatic stress disorders. DISCUSSION: This study aims to understand post-COVID-19 syndrome's incidence and predictors by comparing pandemic waves, utilising retrospective and prospective data. Gender association, especially the potential higher prevalence in females, will be investigated. Symptom tracking via questionnaires and scales will monitor duration and evolution. Questionnaires will also collect data on vaccination, reinfections, and new health issues. Biological samples will enable future studies on post-COVID-19 sequelae mechanisms, including inflammation, immune dysregulation, and viral reservoirs. TRIAL REGISTRATION: This study has been registered with ClinicalTrials.gov under the identifier NCT05531773

Physiological and psychological stress responses to labor and delivery during COVID-19 pandemic: a cohort study

Objective To evaluate objective (saliva cortisol) and subjective (questionnaire) stress levels during the Coronavirus disease (COVID-19) pandemic compared to before the pandemic and their effects on obstetric and neonatal outcomes. Methods This cohort study included 36 women with low-risk, singleton, term deliveries at a tertiary academic center during the COVID-19 pandemic and 49 who delivered before. Physiological stress was evaluated with salivary cortisol measurements, and emotional stress with stress scale questionnaires (0–10) during active and full dilation stages of labor, and 2-min postpartum. Cord blood cortisol and pH were obtained. Delivery mode, complications, and neonatal outcomes were evaluated. Results Psychological stress was higher for the COVID-19 group compared to controls during full dilation (6.2 ± 3.4 vs. 4.2 ± 3, p = .009). The COVID-19 group had significantly lower cord cortisol levels (7.3 vs. 13.6 mcg/dl, p = .001). No differences were found regarding salivary cortisol level assessments at active, full dilation and 2-min post-delivery (p = .584, p = .254, p = .829, respectively). No differences were found regarding pH < 7.1 (p = .487), 1- and 5-min Apgar scores < 7 (p = .179) and neonatal weight (p = .958). Conclusions Women who delivered during COVID-19 pandemic had higher stress levels at full dilation and lower cord cortisol levels, as may be expected after exposure to a chronic stressor