A Mutational Analysis of Conjugation inTetrahymena thermophila

AbstractConjugation in the freshwater ciliateTetrahymena thermophilainvolves a developmental program that models meiosis, fertilization, and early developmental events characteristic of multicellular eukaryotes. We describe a gallery of five early-acting conjugation mutations. These mutants,cnj1–5,exhibit phenotypes in which specific steps in the conjugal pathway have been altered or eliminated. Specifically,cnj1andcnj2fail to condense their micronuclear chromatin prior to each of the three prezygotic nuclear divisions. This results in nuclear division failure, failure to replicate DNA, and failure to initiate postzygotic development. Thecnj3mutant appears to exhibit a defect in chromosome separation during anaphase of mitosis.cnj4mutants successfully carry out meiosis I, yet are unable to execute the second meiotic division and abort all further development.cnj5mutants are unable to initiate either meiosis I or meiosis II, yet proceed to execute all subsequent developmental events. These mutant phenotypes are used to draw inferences regarding developmental dependencies that exist within the conjugation program

Removal of odorants from animal waste using Fenton’s reaction

The purpose of this study was to evaluate Fenton’s reaction as a means of mitigating the problem of offensive odors emitted from livestock manures. The hypothesis to be tested was that hydroxyl radicals generated during this reaction would oxidize odorant compounds, breaking them down to nonodorous products. The deodorization effect was assessed using various chromatographic techniques to determine the concentration of selected odor indicators present in swine slurry and reactor headspaces before and after treatment. The indicators included seven volatile fatty acids, three phenols, and two indoles that were positively correlated with malodors from animal manure. The extent of their removal strongly depended on the concentration of Fenton’s reagents (0 to 40 mM FeCl3, and 0 to 800 mM H2O2), the initial pH of swine slurry (2.0 to 6.5), and the total solids content (0.6 to 2.9% TSC). Control samples treated with no FeCl3 or H2O2 did not show significant reduction of odorant concentration at all pH and TSC levels tested. Acceptable removals of total odorants (65 to 90%) were observed between pH 3.5 and 5.5. When swine slurry (0.7% TSC, pH 5.0) was treated for 2 h with 40 mM FeCl3 at 400 mM H2O2, all odorants were removed completely (100%), except for small amounts of propionic acid. Odorant removal from swine slurry was in good agreement with that from the headspace air (90-100% removal for most measured odorants). Pilot-scale treatment produced encouraging results, surpassing the expectations based on the outcome of laboratory experiments

Dutch Healthcare Professionals’ Opinion on the Allocation of Responsibilities concerning Prescribing and Administering Medically Indicated Vaccines to Immunocompromised Patients

Background: Specific vaccines are indicated for immunocompromised patients (ICPs) due to their vulnerability to infections. Recommendation of these vaccines by healthcare professionals (HCPs) is a crucial facilitator for vaccine uptake. Unfortunately, the responsibilities to recommend and administer these vaccines are not clearly allocated among HCPs involved in the care of adult ICPs. We aimed to evaluate HCPs’ opinions on directorship and their role in facilitating the uptake of medically indicated vaccines as a basis to improve vaccination practices. Methods: A cross-sectional survey was performed among in-hospital medical specialists (MSs), general practitioners (GPs), and public health specialists (PHSs) in the Netherlands to assess their opinion on directorship and the implementation of vaccination care. Additionally, perceived barriers, facilitators, and possible solutions to improve vaccine uptake were investigated. Results: In total, 306 HCPs completed the survey. HCPs almost unanimously (98%) reported that according to them, the primary treating physician is responsible for recommending medically indicated vaccines. Administering these vaccines was seen as a more shared responsibility. The most important barriers experienced by HCPs in recommending and administering were reimbursement problems, a lack of a national vaccination registration system, insufficient collaboration among HCPs, and logistical problems. MSs, GPs and PHSs all mentioned the same three solutions as important strategies to improve vaccination practices, i.e., reimbursement of vaccines, reliable and easily accessible registration of received vaccines, and arrangements for collaboration among the different HCPs that are involved in care. Conclusion: The improvement in vaccination practices in ICPs should focus on better collaboration among MSs, GPs, and PHSs, who should know each other’s expertise; clear agreement on responsibility; reimbursement for vaccines; and the availability of clear registration of vaccination history.</p

Measures of outer setting constructs for implementation research: a systematic review and analysis of psychometric quality

Background: Despite their influence, outer setting barriers (e.g., policies, financing) are an infrequent focus of implementation research. The objective of this systematic review was to identify and assess the psychometric properties of measures of outer setting used in behavioral and mental health research. Methods: Data collection involved (a) search string generation, (b) title and abstract screening, (c) full-text review, (d) construct mapping, and (e) measure forward searches. Outer setting constructs were defined using the Consolidated Framework for Implementation Research (CFIR). The search strategy included four relevant constructs separately: (a) cosmopolitanism, (b) external policy and incentives, (c) patient needs and resources, and (d) peer pressure. Information was coded using nine psychometric criteria: (a) internal consistency, (b) convergent validity, (c) discriminant validity, (d) known-groups validity, (e) predictive validity, (f) concurrent validity, (g) structural validity, (h) responsiveness, and (i) norms. Frequencies were calculated to summarize the availability of psychometric information. Information quality was rated using a 5-point scale and a final median score was calculated for each measure. Results: Systematic searches yielded 20 measures: four measures of the general outer setting domain, seven of cosmopolitanism, four of external policy and incentives, four of patient needs and resources, and one measure of peer pressure. Most were subscales within full scales assessing implementation context. Typically, scales or subscales did not have any psychometric information available. Where information was available, the quality was most often rated as â 1-minimalâ or â 2-adequate.â Conclusion: To our knowledge, this is the first systematic review to focus exclusively on measures of outer setting factors used in behavioral and mental health research and comprehensively assess a range of psychometric criteria. The results highlight the limited quantity and quality of measures at this level. Researchers should not assume â one size fits allâ when measuring outer setting constructs. Some outer setting constructs may be more appropriately and efficiently assessed using objective indices or administrative data reflective of the system rather than the individual

Footprint of publication selection bias on meta-analyses in medicine, environmental sciences, psychology, and economics

Publication selection bias undermines the systematic accumulation of evidence. To assess the extent of this problem, we survey over 68,000 meta-analyses containing over 700,000 effect size estimates from medicine (67,386/597,699), environmental sciences (199/12,707), psychology (605/23,563), and economics (327/91,421). Our results indicate that meta-analyses in economics are the most severely contaminated by publication selection bias, closely followed by meta-analyses in environmental sciences and psychology, whereas meta-analyses in medicine are contaminated the least. After adjusting for publication selection bias, the median probability of the presence of an effect decreased from 99.9% to 29.7% in economics, from 98.9% to 55.7% in psychology, from 99.8% to 70.7% in environmental sciences, and from 38.0% to 29.7% in medicine. The median absolute effect sizes (in terms of standardized mean differences) decreased from d = 0.20 to d = 0.07 in economics, from d = 0.37 to d = 0.26 in psychology, from d = 0.62 to d = 0.43 in environmental sciences, and from d = 0.24 to d = 0.13 in medicine

Footprint of publication selection bias on meta-analyses in medicine, environmental sciences, psychology, and economics

Publication selection bias undermines the systematic accumulation of evidence. To assess the extent of this problem, we survey over 68,000 meta-analyses containing over 700,000 effect size estimates from medicine (67,386/597,699), environmental sciences (199/12,707), psychology (605/23,563), and economics (327/91,421). Our results indicate that meta-analyses in economics are the most severely contaminated by publication selection bias, closely followed by meta-analyses in environmental sciences and psychology, whereas meta-analyses in medicine are contaminated the least. After adjusting for publication selection bias, the median probability of the presence of an effect decreased from 99.9% to 29.7% in economics, from 98.9% to 55.7% in psychology, from 99.8% to 70.7% in environmental sciences, and from 38.0% to 29.7% in medicine. The median absolute effect sizes (in terms of standardized mean differences) decreased from d = 0.20 to d = 0.07 in economics, from d = 0.37 to d = 0.26 in psychology, from d = 0.62 to d = 0.43 in environmental sciences, and from d = 0.24 to d = 0.13 in medicine

Alix is required for activity-dependent bulk endocytosis at brain synapses

In chemical synapses undergoing high frequency stimulation, vesicle components can be retrieved from the plasma membrane via a clathrin-independent process called activitydependent bulk endocytosis (ADBE). Alix (ALG-2-interacting protein X/PDCD6IP) is an adaptor protein binding to ESCRT and endophilin-A proteins which is required for clathrinindependent endocytosis in fibroblasts. Alix is expressed in neurons and concentrates at synapses during epileptic seizures. Here, we used cultured neurons to show that Alix is recruited to presynapses where it interacts with and concentrates endophilin-A during conditions triggering ADBE. Using Alix knockout (ko) neurons, we showed that this recruitment, which requires interaction with the calcium-binding protein ALG-2, is necessary for ADBE. We also found that presynaptic compartments of Alix ko hippocampi display subtle morphological defects compatible with flawed synaptic activity and plasticity detected electrophysiologically. Furthermore, mice lacking Alix in the forebrain undergo less seizures during kainate-induced status epilepticus and reduced propagation of the epileptiform activity. These results thus show that impairment of ADBE due to the lack of neuronal Alix leads to abnormal synaptic recovery during physiological or pathological repeated stimulations