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Introduction: This article focuses on medical fatphobia as a specific phenomenon structuring interactions between patients and healthcare practitioners. Throughout the article, we use 'fat' and 'fatphobia' as the preferred terms in the body positivity and fat acceptance communities. It is well documented that 'fat' people frequently experience negative and highly stigmatising healthcare encounters where weight is disproportionately centred and over-attributed as a cause of ill-health. This can compound and worsen disordered eating, trigger mental health problems, and lead to healthcare avoidance. Although the regularity and risks of these weight-focused encounters are well established, there does not yet exist a coherent theoretical framework for understanding such discriminatory practises., Methods: In this article, we draw on the experiences of 15 fat women who are members of the Health at Every Size (HAES) online community to explore how they perceive their fatness impacting medical encounters., Results and Discussion: Through these data and specifically drawing on the framework of 'cultural health capital,' we suggest that given the deep purchase of cultural tropes surrounding it, fatness is perceived to embody and therefore confer on patients' assumptions of low cultural health capital. We argue that ubiquitously characteristic of medical fatphobia is what we call an 'interactional and relational disconnect' between fat patients and healthcare practitioners. We suggest that this disconnect structures fatphobic interactions by over-attributing fatness as the underlying cause of medical problems, which entrenches patient and practitioner ambivalence because of a lack of joint decision-making. We argue that interactional and relational disconnect is produced by, sustained by, and reproduces asymmetric power relations between patients and practitioners. While we demonstrate that patients develop tactics to mitigate and manage fatphobia in healthcare encounters, the persistent interactional asymmetry between doctors and patients means these attempts often fail. We conclude with a plea for sociology to take medical fatphobia seriously as a form of intersectional systemic discrimination. While movements like HAES, fat positivity, and body acceptance create kinship and support fat patients with self-advocacy in healthcare interactions, we suggest that systemic rather than individual change is necessary for effective healthcare inclusion and interaction., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Kost, Jamie and Mohr.)

Microbial communities drive global biogeochemical cycles and shape the health of plants and animals-including humans. Their structure and function are determined by ecological and environmental interactions that govern the assembly, stability and evolution of microbial communities. A widely held view is that antagonistic interactions such as competition predominate in microbial communities and are ecologically more important than synergistic interactions-for example, mutualism or commensalism. Over the past decade, however, a more nuanced picture has emerged, wherein bacteria, archaea and fungi exist within interactive networks in which they exchange essential and non-essential metabolites. These metabolic interactions profoundly impact not only the physiology, ecology and evolution of the strains involved, but are also central to the functioning of many, if not all, microbiomes. Therefore, we advocate for a balanced view of microbiome ecology that encompasses both synergistic and antagonistic interactions as key forces driving the structure and dynamics within microbial communities., (© 2023. Springer Nature Limited.)

Bacteria are ubiquitous and colonize virtually every conceivable habitat on earth. To achieve this, bacteria require different metabolites and biochemical capabilities. Rather than trying to produce all of the needed materials by themselves, bacteria have evolved a range of synergistic interactions, in which they exchange different commodities with other members of their local community. While it is widely acknowledged that synergistic interactions are key to the ecology of both individual bacteria and entire microbial communities, the factors determining their establishment remain poorly understood. Here we provide a comprehensive overview over our current knowledge on the determinants of positive cell-cell interactions among bacteria. Taking a holistic approach, we review the literature on the molecular mechanisms bacteria use to transfer commodities between bacterial cells and discuss to which extent these mechanisms favour or constrain the successful establishment of synergistic cell-cell interactions. In addition, we analyse how these different processes affect the specificity among interaction partners. By drawing together evidence from different disciplines that study the focal question on different levels of organisation, this work not only summarizes the state of the art in this exciting field of research, but also identifies new avenues for future research., (© 2023 Walter de Gruyter GmbH, Berlin/Boston.)

Competing Interests: Declaration of interests D.S. is a member of the DOE Biological and Environmental Research Advisory Committee and the KBase science advisory committee. G.E.L. is an employee and shareholder of PharmaBiome AG. G.E.L. is an inventor on patent application number WO2022023458 entitled "Microbial Niche Mapping."

Explaining the de novo evolution of obligate cooperative cross-feeding interactions among bacteria is a fundamental problem. A critical step during this process is the emergence of reciprocity among two interaction partners, because a mutually beneficial exchange of metabolic byproducts can subsequently favour the evolution of cooperative cross-feeding. However, so far, the propensity with which unidirectional cross-feeding interactions transition into bidirectional interactions remains unknown. To address this issue, we systematically cocultured four amino acid auxotrophic genotypes of two bacterial species with potential amino acid donors belonging to 25 different bacterial species. Surprisingly, the results of this experiment revealed that in around 40% of all cases analysed, both the auxotrophic recipient and the metabolically autonomous donor gained a significant growth advantage in coculture. Subsequent experiments clarified that the auxotrophy-causing mutation did not induce the growth-enhancing effect of recipients, but that it was rather due to a generally high propensity of different species to engage in synergistic metabolic interactions. Together, these findings show that reciprocity commonly emerges spontaneously in unidirectional cross-feeding interactions, thus paving the way for the evolution of even tighter metabolic interactions., (© 2022. The Author(s).)

Individual-based modeling is widely applied to investigate the ecological mechanisms driving microbial community dynamics. In such models, the population or community dynamics emerge from the behavior and interplay of individual entities, which are simulated according to a predefined set of rules. If the rules that govern the behavior of individuals are based on generic and mechanistically sound principles, the models are referred to as next-generation individual-based models. These models perform particularly well in recapitulating actual ecological dynamics. However, implementation of such models is time-consuming and requires proficiency in programming or in using specific software, which likely hinders a broader application of this powerful method. Here we present McComedy, a modeling tool designed to facilitate the development of next-generation individual-based models of microbial consumer-resource systems. This tool allows flexibly combining pre-implemented building blocks that represent physical and biological processes. The ability of McComedy to capture the essential dynamics of microbial consumer-resource systems is demonstrated by reproducing and furthermore adding to the results of two distinct studies from the literature. With this article, we provide a versatile tool for developing next-generation individual-based models that can foster understanding of microbial ecology in both research and education., Competing Interests: The authors have declared that no competing interests exist.

Cooperative mutualisms are widespread and play fundamental roles in many ecosystems. Given that these interactions are often obligate, the Darwinian fitness of the participating individuals is not only determined by the information encoded in their own genomes, but also the traits and capabilities of their corresponding interaction partners. Thus, a major outstanding question is how obligate cooperative mutualisms affect the ability of organisms to adapt evolutionarily to changing environmental conditions. Here we address this issue using a mutualistic cooperation between two auxotrophic genotypes of Escherichia coli that reciprocally exchanged costly amino acids. Amino acid-supplemented monocultures and unsupplemented cocultures were exposed to stepwise increasing concentrations of different antibiotics. This selection experiment reveals that metabolically interdependent bacteria are generally less able to adapt to environmental stress than autonomously growing strains. Moreover, obligate cooperative mutualists frequently regain metabolic autonomy, resulting in a collapse of the mutualistic interaction. Together, our results identify a limited evolvability as a significant evolutionary cost that individuals have to pay when entering into an obligate mutualistic cooperation., (© 2022. The Author(s).)

The exchange of metabolites among different bacterial genotypes profoundly impacts the structure and function of microbial communities. However, the factors governing the establishment of these cross-feeding interactions remain poorly understood. While shared physiological features may facilitate interactions among more closely related individuals, a lower relatedness should reduce competition and thus increase the potential for synergistic interactions. Here, we investigate how the relationship between a metabolite donor and recipient affects the propensity of strains to engage in unidirectional cross-feeding interactions. For this, we performed pairwise cocultivation experiments between four auxotrophic recipients and 25 species of potential amino acid donors. Auxotrophic recipients grew in the vast majority of pairs tested (63%), suggesting metabolic cross-feeding interactions are readily established. Strikingly, both the phylogenetic distance between donor and recipient and the dissimilarity of their metabolic networks were positively associated with the growth of auxotrophic recipients. Analyzing the co-growth of species from a gut microbial community in silico also revealed that recipient genotypes benefitted more from interacting with metabolically dissimilar partners, thus corroborating the empirical results. Together, our work identifies the metabolic dissimilarity between bacterial genotypes as a key factor determining the establishment of metabolic cross-feeding interactions in microbial communities., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Bacteria frequently engage in obligate metabolic mutualisms with other microorganisms. However, it remains generally unclear how the resulting metabolic dependencies affect the ecological niche space accessible to the whole consortium relative to the niche space available to its constituent individuals. Here we address this issue by systematically cultivating metabolically dependent strains of different bacterial species either individually or as pairwise cocultures in a wide range of carbon sources. Our results show that obligate cross-feeding is significantly more likely to expand the metabolic niche space of interacting bacterial populations than to contract it. Moreover, niche expansion occurred predominantly between two specialist taxa and correlated positively with the phylogenetic distance between interaction partners. Together, our results demonstrate that obligate cross-feeding can significantly expand the ecological niche space of interacting bacterial genotypes, thus explaining the widespread occurrence of this type of ecological interaction in natural microbiomes., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

In an iconicity judgement task, participants were asked whether word pairs were iconic (e.g., nose-tongue; joy-sorrow ) or reverse-iconic (e.g., tongue-nose; sorrow-joy ), and an advantage for abstract word pairs (i.e., joy-sorrow ) was found. Malhi and Buchanan proposed that this reverse concreteness, or abstractness, effect was the result of participants taking a visualisation/imagining (time-costly) approach towards the concrete word pairs and an emotional/intuitive (time-efficient) approach towards the abstract word pairs. This study tested this proposal by asking participants questions about strategy use (Experiment 1). In the forced-choice questions, all participants reported using a visualisation/imagining approach towards the concrete word pairs and most participants reported using an emotional/intuitive approach towards the abstract word pairs. In the open-ended responses, visual-spatial reasoning and real-life experience emerged as themes for the concrete word pairs and social norms and values emerged as themes for the abstract word pairs, adding to our understanding of the grounding of abstract words. In Experiment 2, participants were supplied with pictures as an aid to visualisation with the expectation that this would reduce the time required for concrete word processing. Supplying pictures made participants faster and more accurate at completing the task. Experiment 3 manipulated the type of visual aid by also supplying pictures that did not match the orientation of the word pairs. Participants were only more accurate when the pictures were in the correct and iconic spatial arrangement. A flexible abstractness and concreteness effects (FACE) theory is proposed which integrates symbolic and embodied accounts and introduces constructs such as direct and constrained imageability for concrete words and indirect and free imageability for abstract words.

Mutually beneficial interactions are ubiquitous in nature and have played a pivotal role for the evolution of life on earth. However, the factors facilitating their emergence remain poorly understood. Here, we address this issue both experimentally and by mathematical modeling using cocultures of auxotrophic strains of Escherichia coli, whose growth depends on a reciprocal exchange of amino acids. Coevolving auxotrophic pairs in a spatially heterogeneous environment for less than 150 generations transformed the initial interaction that was merely based on an exchange of metabolic byproducts into a costly metabolic cooperation, in which both partners increased the amounts of metabolites they produced to benefit their corresponding partner. The observed changes were afforded by the formation of multicellular clusters, within which increased cooperative investments were favored by positive fitness feedbacks among interacting genotypes. Under these conditions, non-cooperative individuals were less fit than cooperative mutants. Together, our results highlight the ease with which mutualistic cooperation can evolve, suggesting similar mechanisms likely operate in natural communities. VIDEO ABSTRACT., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Insects frequently harbor multiple symbionts that collectively provide them with essential nutrients. Comparing several recent and ancient associations revealed a strikingly parallel pattern, by which a new symbiont was integrated into a preexisting host-symbiont interaction., (Copyright © 2020 Elsevier Inc. All rights reserved.)