Phenotypic responses to interspecies competition and commensalism in a naturally derived microbial co-culture

The fundamental question of whether different microbial species will co-exist or compete in a given environment depends on context, composition and environmental constraints. Model microbial systems can yield some general principles related to this question. In this study we employed a naturally occurring co-culture composed of heterotrophic bacteria, Halomonas sp. HL-48 and Marinobacter sp. HL- 58, to ask two fundamental scientific questions: 1) how do the phenotypes of two naturally co-existing species respond to partnership as compared to axenic growth? and 2) how do growth and molecular phenotypes of these species change with respect to competitive and commensal interactions? We hypothesized – and confirmed – that co-cultivation under glucose as the sole carbon source would result in competitive interactions. Similarly, when glucose was swapped with xylose, the interactions became commensal because Marinobacter HL-58 was supported by metabolites derived from Halomonas HL- 48. Each species responded to partnership by changing both its growth and molecular phenotype as assayed via batch growth kinetics and global transcriptomics. These phenotypic responses depended on nutrient availability and so the environment ultimately controlled how they responded to each other. This simplified model community revealed that microbial interactions are context-specific and different environmental conditions dictate how interspecies partnerships will unfold

Phenotypic responses to interspecies competition and commensalism in a naturally derived microbial co-culture

The fundamental question of whether different microbial species will co-exist or compete in a given environment depends on context, composition and environmental constraints. Model microbial systems can yield some general principles related to this question. In this study we employed a naturally occurring co-culture composed of heterotrophic bacteria, Halomonas sp. HL-48 and Marinobacter sp. HL- 58, to ask two fundamental scientific questions: 1) how do the phenotypes of two naturally co-existing species respond to partnership as compared to axenic growth? and 2) how do growth and molecular phenotypes of these species change with respect to competitive and commensal interactions? We hypothesized – and confirmed – that co-cultivation under glucose as the sole carbon source would result in competitive interactions. Similarly, when glucose was swapped with xylose, the interactions became commensal because Marinobacter HL-58 was supported by metabolites derived from Halomonas HL- 48. Each species responded to partnership by changing both its growth and molecular phenotype as assayed via batch growth kinetics and global transcriptomics. These phenotypic responses depended on nutrient availability and so the environment ultimately controlled how they responded to each other. This simplified model community revealed that microbial interactions are context-specific and different environmental conditions dictate how interspecies partnerships will unfold

Resisting the mantle of the monstrous feminine : women's construction and experience of premenstrual embodiment

The female reproductive body is positioned as abject, as other, as site of defciency and disease, the epitome of the ‘monstrous feminine.’ Premenstrual change in emotion, behavior or embodied sensation is positioned as a sign of madness within, necessitating restraint and control on the part of the women experiencing it (Ussher 2006). Breakdown in this control through manifestation of ‘symptoms’ is diagnosed as PMS (Premenstrual Syndrome) or PMDD (Premenstrual Dysphoric Disorder), a pathology deserving of ‘treatment.’ In this chapter, we adopt a feminist material-discursive theoretical framework to examine the role of premenstrual embodiment in relation to women’s adoption of the subject position of monstrous feminine, drawing on interviews we have conducted with women who self-diagnose as ‘PMS sufferers.’ We theorize women’s self-positioning as subjectifcation, wherein women take up cultural discourse associated with idealized femininity and the reproductive body, resulting in self-objectifcation, distress, and self-condemnation. However, women can resist negative cultural constructions of premenstrual embodiment and the subsequent self-policing. We describe the impact of women-centered psychological therapy which increases awareness of embodied change, and leads to greater acceptance of the premenstrual body and greater self-care, which serves to reduce premenstrual distress

Groups and individuals: conformity and diversity in the performance of gendered identities

The nature and role of social groups is a central tension in sociology. On the one hand, the idea of a group enables sociologists to locate and describe individuals in terms of characteristics that are shared with others. On the other, emphasizing the fluidity of categories such as gender or ethnicity undermines their legitimacy as ways of classifying people and, by extension, the legitimacy of categorization as a goal of sociological research. In this paper, we use a new research method known as the Imitation Game to defend the social group as a sociological concept. We show that, despite the diversity of practices that may be consistent with self‐identified membership of a group, there are also shared normative expectations – typically narrower in nature than the diversity displayed by individual group members – that shape the ways in which category membership can be discussed with, and performed to, others. Two claims follow from this. First, the Imitation Game provides a way of simultaneously revealing both the diversity and ‘groupishness’ of social groups. Second, that the social group, in the quasi‐Durkheimian sense of something that transcends the individual, remains an important concept for sociology

Anti-Effeminacy Moderates the Relationship Between Masculinity and Internalized Heterosexism Among Gay Men

Internalized heterosexism (IH) is linked to negative mental health outcomes among people who are lesbian, gay, and bisexual. This study examined whether anti-effeminacy moderates the relationship between masculinity and IH among gay men in the United States. The participants were 239 gay men who completed measures of masculinity, anti-effeminacy, and IH. Results indicated that anti-effeminacy and masculinity predicted IH and that anti-effeminacy moderated the relationship between masculinity and IH. These findings suggest that, to reduce IH and its deleterious mental health effects, counselors should work with their male clients who are gay to reduce their anti-effeminacy and sexism

Forfeiting the priority effect: turnover defines biofilm community succession

Microbial community succession is a fundamental process that affects underlying functions of almost all ecosystems; yet the roles and fates of the most abundant colonizers are often poorly understood. Does early abundance spur long term persistence? How do deterministic and stochastic processes influence the ecological contribution of colonizers? We performed a succession experiment within a hypersaline ecosystem to investigate how different processes contributed to the turnover of founder species. Bacterial and eukaryotic colonizers were identified during primary succession and tracked through a defined, 79-day biofilm maturation period using 16S and 18S rRNA gene sequencing in combination with high resolution imaging that utilized stable isotope tracers to evaluate successional patterns of primary producers and nitrogen fixers. The majority of the founder species did not maintain high abundance throughout succession. Species replacement (versus loss) was the dominant process shaping community succession. We also asked if different ecological processes acted on bacteria versus Eukaryotes during succession and found deterministic and stochastic forces corresponded more with microeukaryote and bacterial colonization, respectively. Our results show that taxa and functions belonging to different kingdoms, which share habitat in the tight spatial confines of a biofilm, were influenced by different ecological processes and time scales of succession