Net overboard: Comparing marine eDNA sampling methodologies at sea to unravel marine biodiversity

Environmental DNA (eDNA) analyses are powerful for describing marine biodiversity but must be optimized for their effective use in routine monitoring. To maximize eDNA detection probabilities of sparsely distributed populations, water samples are usually concentrated from larger volumes and filtered using fine-pore membranes, often a significant cost–time bottleneck in the workflow. This study aimed to streamline eDNA sampling by investigating plankton net versus bucket sampling, direct versus sequential filtration including self-preserving filters. Biodiversity was assessed using metabarcoding of the small ribosomal subunit (18S rRNA) and mitochondrial cytochrome c oxidase I (COI) genes. Multispecies detection probabilities were estimated for each workflow using a probabilistic occupancy modelling approach. Significant workflow-related differences in biodiversity metrics were reported. Highest amplicon sequence variant (ASV) richness was attained by the bucket sampling combined with self-preserving filters, comprising a large portion of microplankton. Less diversity but more metazoan taxa were captured in the net samples combined with 5 μm pore size filters. Prefiltered 1.2 μm samples yielded few or no unique ASVs. The highest average (~32%) metazoan detection probabilities in the 5 μm pore size net samples confirmed the effectiveness of preconcentration plankton for biodiversity screening. These results contribute to streamlining eDNA sampling protocols for uptake and implementation in marine biodiversity research and surveillance.     

Mating practices and the dissemination of genetic disorders in domestic animals,based on the example of dog breeding

On the basis of simulations and genealogical data of ten dog breeds, three popular mating practices (popular sire effect, line breeding, close breeding) were investigated along with their effects on the dissemination of genetic disorders. Our results showed that the use of sires in these ten breeds is clearly unbalanced. Depending on the breed, the effective number of sires represented between 33% and 70% of the total number of sires. Mating between close relatives was also found to be quite common, and the percentage of dogs inbred after two generations ranged from 1% to about 8%. A more or less long‐term genetic differentiation, linked to line breeding practices, was also emphasized in most breeds. F_IT index based on gene dropping proved to be efficient in differentiating the effects of the different mating practices, and it ranged from ?1.3% to 3.2% when real founders were used to begin a gene dropping process. Simulation results confirmed that the popular sire practice leads to a dissemination of genetic disorders. Under a realistic scenario, regarding the imbalance in the use of sires, the dissemination risk was indeed 4.4 times higher than under random mating conditions. In contrast, line breeding and close breeding practices tend to decrease the risk of the dissemination of genetic disorders.     

Making sense of medically unexplained symptoms in general practice: a grounded theory study

Background General practitioners often encounter patients with medically unexplained symptoms. These patients share many common features, but there is little agreement about the best diagnostic framework for describing them.Aims This study aimed to explore how GPs make sense of medically unexplained symptoms.Design Semi-structured interviews were conducted with 24 GPs. Each participant was asked to describe a patient with medically unexplained symptoms and discuss their assessment and management.Setting The study was conducted among GPs from teaching practices across Australia.Methods Participants were selected by purposive sampling and all interviews were transcribed. Iterative analysis was undertaken using constructivist grounded theory methodology.Results GPs used a variety of frameworks to understand and manage patients with medically unexplained symptoms. They used different frameworks to reason, to help patients make sense of their suffering, and to communicate with other health professionals. GPs tried to avoid using stigmatising labels such as ‘borderline personality disorder’, which were seen to apply a ‘layer of dismissal’ to patients. They worried about missing serious physical disease, but managed the risk by deliberately attending to physical cues during some consultations, and focusing on coping with medically unexplained symptoms in others. They also used referrals to exclude serious disease, but were wary of triggering a harmful cycle of uncoordinated care.Conclusion GPs were aware of the ethical relevance of psychiatric diagnoses, and attempted to protect their patients from stigma. They crafted helpful explanatory narratives for patients that shaped their experience of suffering. Disease surveillance remained an important role for GPs who were managing medically unexplained symptoms.     

REFLECTIVE EQUILIBRIUM AND EMPIRICAL DATA: THIRD PERSON MORAL EXPERIENCES IN EMPIRICAL MEDICAL ETHICS

In ethics, the use of empirical data has become more and more popular, leading to a distinct form of applied ethics, namely empirical ethics. This ‘empirical turn’ is especially visible in bioethics. There are various ways of combining empirical research and ethical reflection. In this paper we discuss the use of empirical data in a special form of Reflective Equilibrium (RE), namely the Network Model with Third Person Moral Experiences. In this model, the empirical data consist of the moral experiences of people in a practice. Although inclusion of these moral experiences in this specific model of RE can be well defended, their use in the application of the model still raises important questions. What precisely are moral experiences? How to determine relevance of experiences, in other words: should there be a selection of the moral experiences that are eventually used in the RE? How much weight should the empirical data have in the RE? And the key question: can the use of RE by empirical ethicists really produce answers to practical moral questions? In this paper we start to answer the above questions by giving examples taken from our research project on understanding the norm of informed consent in the field of pediatric oncology. We especially emphasize that incorporation of empirical data in a network model can reduce the risk of self‐justification and bias and can increase the credibility of the RE reached.     

REASONS TO REDEFINE MORAL DISTRESS: A FEMINIST EMPIRICAL BIOETHICS ANALYSIS

There has been increasing debate in recent years about the conceptualization of moral distress. Broadly speaking, two groups of scholars have emerged: those who agree with Jameton’s ‘narrow definition’ that focuses on constraint and those who argue that Jameton’s definition is insufficient and needs to be broadened. Using feminist empirical bioethics, we interviewed critical care nurses in the United Kingdom about their experiences and conceptualizations of moral distress. We provide our broader definition of moral distress and examples of data that both challenge and support our conceptualization. We pre‐empt and overcome three key challenges that could be levelled at our account and argue that there are good reasons to adopt our broader definition of moral distress when exploring prevalence of, and management strategies for, moral distress.     

The Laboratory Technology of Discrete Molecular Separation: The Historical Development of Gel Electrophoresis and the Material Epistemology of Biomolecular Science, 1945–1970

Preparative and analytical methods developed by separation scientists have played an important role in the history of molecular biology. One such early method is gel electrophoresis, a technique that uses various types of gel as its supporting medium to separate charged molecules based on size and other properties. Historians of science, however, have only recently begun to pay closer attention to this material epistemological dimension of biomolecular science. This paper substantiates the historiographical thread that explores the relationship between modern laboratory practice and the production of scientific knowledge. It traces the historical development of gel electrophoresis from the mid-1940s to the mid-1960s, with careful attention to the interplay between technical developments and disciplinary shifts, especially the rise of molecular biology in this time-frame. Claiming that the early 1950s marked a decisive shift in the evolution of electrophoretic methods from moving boundary to zone electrophoresis, I reconstruct various trajectories in which scientists such as Oliver Smithies sought out the most desirable solid supporting medium for electrophoretic instrumentation. Biomolecular knowledge, I argue, emerged in part from this process of seeking the most appropriate supporting medium that allowed for discrete molecular separation and visualization. The early 1950s, therefore, marked not only an important turning point in the history of separation science, but also a transformative moment in the history of the life sciences as the growth of molecular biology depended in part on the epistemological access to the molecular realm available through these evolving technologies.