Effects of Pyruvate Decarboxylase Overproduction on Flux Distribution at the Pyruvate Branch Point in Saccharomyces cerevisiae

A multicopy plasmid carrying the PDC1 gene (encoding pyruvate decarboxylase; Pdc) was introduced in Saccharomyces cerevisiae CEN.PK113-5D. The physiology of the resulting prototrophic strain was compared with that of the isogenic prototrophic strain CEN.PK113-7D and an empty-vector reference strain. In glucose-grown shake-flask cultures, the introduction of the PDC1 plasmid caused a threefold increase in the Pdc level. In aerobic glucose-limited chemostat cultures growing at a dilution rate of 0.10 h(−1), Pdc levels in the overproducing strain were 14-fold higher than those in the reference strains. Levels of glycolytic enzymes decreased by ca. 15%, probably due to dilution by the overproduced Pdc protein. In chemostat cultures, the extent of Pdc overproduction decreased with increasing dilution rate. The high degree of overproduction of Pdc at low dilution rates did not affect the biomass yield. The dilution rate at which aerobic fermentation set in decreased from 0.30 h(−1) in the reference strains to 0.23 h(−1) in the Pdc-overproducing strain. In the latter strain, the specific respiration rate reached a maximum above the dilution rate at which aerobic fermentation first occurred. This result indicates that a limited respiratory capacity was not responsible for the onset of aerobic fermentation in the Pdc-overproducing strain. Rather, the results indicate that Pdc overproduction affected flux distribution at the pyruvate branch point by influencing competition for pyruvate between Pdc and the mitochondrial pyruvate dehydrogenase complex. In respiratory cultures (dilution rate, <0.23 h(−1)), Pdc overproduction did not affect the maximum glycolytic capacity, as determined in anaerobic glucose-pulse experiments

Metaproteomics, metagenomics and 16S rRNA sequencing provide different perspectives on the aerobic granular sludge microbiome

Abstract: The tremendous progress in sequencing technologies has made DNA sequencing routine for microbiome studies. Additionally, advances in mass spectrometric techniques have extended conventional proteomics into the field of microbial ecology. However, systematic studies that provide a better understanding of the complementary nature of these 'omics' approaches, particularly for complex environments such as wastewater treatment sludge, are urgently needed.Here, we describe a comparative metaomics study on aerobic granular sludge from three different wastewater treatment plants. For this, we employed metaproteomics, whole metagenome, and 16S rRNA amplicon sequencing to study the same granule material with uniform size. We furthermore compare the taxonomic profiles using the Genome Taxonomy Database (GTDB) to enhance the comparability between the different approaches. Though the major taxonomies were consistently identified in the different aerobic granular sludge samples, the taxonomic composition obtained by the different omics techniques varied significantly at the lower taxonomic levels, which impacts the interpretation of the nutrient removal processes. Nevertheless, as demonstrated by metaproteomics, the genera that were consistently identified in all techniques cover the majority of the protein biomass. The established metaomics data and the contig classification pipeline are publicly available, which provides a valuable resource for further studies on metabolic processes in aerobic granular sludge

Online computer or therapist-guided cognitive behavioral therapy in university students with anxiety and/or depression: Study protocol of a randomised controlled trial

Introduction Emerging adulthood is a phase in life that is associated with an increased risk to develop a variety of mental health disorders including anxiety and depression. However, less than 25% of university students receive professional help for their mental health reports. Internet-based cognitive behavioural therapy (iCBT) may entail useful interventions in a format that is attractive for university students. The aim of this study protocol is to test the effectiveness of a therapist-guided versus a computer-guided transdiagnostic iCBT programme with a main focus on anxiety and depression. Methods and analysis University students with anxiety and/or depressive symptoms will be randomised to a (1) 7-week iCBT programme (excluding booster session) with therapist feedback, (2) the identical iCBT programme with computer feedback only or (3) care as usual. Participants in the care as usual condition are informed and referred to conventional care services and encouraged to seek the help they need. Primary outcome variables are self-reported levels of anxiety as measured with the General Anxiety Disorder-7 and self-reported levels of depression as measured with the Patient Health Questionnaire-9. Secondary outcomes include treatment adherence, client satisfaction, medical service use, substance use, quality of life and academic achievement. Assessments will take place at baseline (t1), midtreatment (t2), post-treatment (t3), at 6 months (t4) and 12 months (t5) postbaseline. Social anxiety and perfectionism are included as potentially important predictors of treatment outcome. Power calculations are based on a 3 (group) × 3 (measurement: pretreatment, midtreatment and post-treatment) interaction, resulting in an aimed sample of 276 participants. Data will be analysed based on intention-to-treat and per protocol samples using mixed linear models

Can we Save the rectum by watchful waiting or TransAnal surgery following (chemo)Radiotherapy versus Total mesorectal excision for early REctal Cancer (STAR‐TREC)? Protocol for the international, multicentre, rolling phase II/III partially randomised patient preference trial evaluating long course concurrent chemoradiotherapy versus short course radiotherapy organ preservation approaches

International audienceAim: Organ-saving treatment for early-stage rectal cancer can reduce patient-reported side effects compared to standard total mesorectal excision (TME) and preserve quality of life. An optimal strategy for achieving organ preservation and longer-term oncological outcomes are unknown; thus there is a need for high quality trials.Method: Can we Save the rectum by watchful waiting or TransAnal surgery following (chemo)Radiotherapy versus Total mesorectal excision for early REctal Cancer (STAR-TREC) is an international three-arm multicentre, partially randomized controlled trial incorporating an external pilot. In phase III, patients with cT1-3b N0 tumours, ≤40 mm in diameter, who prefer organ preservation are randomized 1:1 between mesorectal long-course chemoradiation versus mesorectal short-course radiotherapy, with selective transanal microsurgery. Patients preferring radical surgery receive TME. STAR-TREC aims to recruit 380 patients to organ preservation and 120 to TME surgery. The primary outcome is the rate of organ preservation at 30 months. Secondary clinician-reported outcomes include acute treatment-related toxicity, rate of non-operative management, non-regrowth pelvic tumour control at 36 months, non-regrowth disease-free survival at 36 months and overall survival at 60 months, and patient-reported toxicity, health-related quality of life at baseline, 12 and 24 months. Exploratory biomarker research uses circulating tumour DNA to predict response and relapse.Discussion: STAR-TREC will prospectively evaluate contrasting therapeutic strategies and implement new measures including a smaller mesorectal target volume, two-step response assessment and non-operative management for complete response. The trial will yield important information to guide routine management of patients with early-stage rectal cancer