The Antimicrobial Peptide Histatin-5 Causes a Spatially Restricted Disruption on the Candida albicans Surface, Allowing Rapid Entry of the Peptide into the Cytoplasm

Antimicrobial peptides play an important role in host defense against microbial pathogens. Their high cationic charge and strong amphipathic structure allow them to bind to the anionic microbial cell membrane and disrupt the membrane bilayer by forming pores or channels. In contrast to the classical pore-forming peptides, studies on histatin-5 (Hst-5) have suggested that the peptide is transported into the cytoplasm of Candida albicans in a non-lytic manner, and cytoplasmic Hst-5 exerts its candicidal activities on various intracellular targets, consistent with its weak amphipathic structure. To understand how Hst-5 is internalized, we investigated the localization of FITC-conjugated Hst-5. We find that Hst-5 is internalized into the vacuole through receptor-mediated endocytosis at low extracellular Hst-5 concentrations, whereas under higher physiological concentrations, Hst-5 is translocated into the cytoplasm through a mechanism that requires a high cationic charge on Hst-5. At intermediate concentrations, two cell populations with distinct Hst-5 localizations were observed. By cell sorting, we show that cells with vacuolar localization of Hst-5 survived, while none of the cells with cytoplasmic Hst-5 formed colonies. Surprisingly, extracellular Hst-5, upon cell surface binding, induces a perturbation on the cell surface, as visualized by an immediate and rapid internalization of Hst-5 and propidium iodide or rhodamine B into the cytoplasm from the site using time-lapse microscopy, and a concurrent rapid expansion of the vacuole. Thus, the formation of a spatially restricted site in the plasma membrane causes the initial injury to C. albicans and offers a mechanism for its internalization into the cytoplasm. Our study suggests that, unlike classical channel-forming antimicrobial peptides, action of Hst-5 requires an energized membrane and causes localized disruptions on the plasma membrane of the yeast. This mechanism of cell membrane disruption may provide species-specific killing with minimal damage to microflora and the host and may be used by many other antimicrobial peptides

Hyper-compressions: The rise of flash fiction in “post-transitional” South Africa

Blair, P. (2020). Hyper-compressions: The rise of flash fiction in “post-transitional” South Africa', The Journal of Commonwealth Literature, 55(1), 38-60. Copyright © 2018. Reprinted by permission of SAGE Publications.This article begins with a survey of flash fiction in “post-transitional” South Africa, which it relates to the nation’s post-apartheid canon of short stories and short-short stories, to the international rise of flash fiction and “sudden fiction”, and to the historical particularities of South Africa’s “post-transition”. It then undertakes close readings of three flash fictions republished in the article, each less than 450 words: Tony Eprile’s “The interpreter for the tribunal” (2007), which evokes the psychological and ethical complexities, and long-term ramifications, of the Truth and Reconciliation Commission; Michael Cawood Green’s “Music for a new society” (2008), a carjacking story that invokes discourses about violent crime and the “‘new’ South Africa”; and Stacy Hardy’s “Kisula” (2015), which maps the psychogeography of cross-racial sex and transnational identity-formation in an evolving urban environment. The article argues that these exemplary flashes are “hyper-compressions”, in that they compress and develop complex themes with a long literary history and a wide contemporary currency. It therefore contends that flash fiction of South Africa’s post-transition should be recognized as having literary-historical significance, not just as an inherently metonymic form that reflects, and alludes to, a broader literary culture, but as a genre in its own right

Counselling formerly heterosexually partnered gay fathers raised with religion

Formerly heterosexually partnered gay fathers raised with religion are an under-researched group of LGBTQ parents. This group have potentially complex coming out journeys, which can result in them seeking counselling. This research explores the counselling experiences of such men and offers suggestions for working therapeutically with them. Twelve self-identified gay fathers participated in qualitative interviews. These men all had children in the context of a heterosexual marriage or committed partnership, and a religious upbringing of some kind in the US, Canada, the UK or Ireland. The key finding of the qualitative analysis was that participants wanted therapists to not assume a ‘best’ outcome for them as either gay or ‘straight’. Instead, they wanted therapists to respect and assist them to explore their own individual sense-making around their identities and to reject fixed notions from both ex-gay and (some versions of) gay affirmative therapy of what it means to be a ‘well-adjusted’ (gay) father

Reflections on the challenges of understanding racial, cultural and sexual differences in couple relationship research

In the field of systemic psychotherapy there has been much recent interest in the areas of culture and reflexivity, and in working with couples. In this article we reflect on the process of conducting research in these areas. Drawing on findings from a large, national, empirical mixed-methods study on long-term relationships, we use two examples from the data to illustrate the complexity of researching across racial, cultural and sexual differences, in terms of research design and sampling, fieldwork and research practice, and making sense of multidimensional data. We point to findings that suggest that notions of coupledom are culturally constructed and thus challenge straightforward ideas of the procreative, sexually active couple dyad, separate from intergenerational extended families. The clinical significance of the findings for both lesbian, gay, bisexual or queer and culturally diverse couples and families are discussed

Molecular diagnosis of Pneumocystis pneumonia in dogs

Pneumocystis pneumonia (PCP) is a life-threatening fungal disease that can occur in dogs. The aim of this study was to provide a preliminary genetic characterisation of Pneumocystis carinii f. sp. 'canis' (P. canis) in dogs and thereby develop a reliable molecular protocol to definitively diagnose canine PCP. We investigated P. canis in a variety of lung specimens from dogs with confirmed or strongly suspected PCP (Group 1, n = 16), dogs with non-PCP lower respiratory tract problems (Group 2, n = 65) and dogs not suspected of having PCP or other lower respiratory diseases (Group 3, n = 11). Presence of Pneumocystis DNA was determined by nested PCR of the large and small mitochondrial subunit rRNA loci and by a real-time quantitative polymerase chain reaction (qPCR) assay developed using a new set of primers. Molecular results were correlated with the presence of Pneumocystis morphotypes detected in cytological/histological prepa rations. Pneumocystis DNA was amplified from 13/16 PCP-suspected dogs (Group 1) and from 4/76 dogs of control Groups 2 and 3 (combined). The latter four dogs were thought to have been colonized by P. canis. Comparison of C-T values in 'infected' versus 'colonized' dogs was consistent with this notion, with a distinct difference in molecular burden between groups (C-T <= 26 versus C-T range (26 < C-T < 35), respectively). Phylogenetic analyses showed that P. canis is specifically 'canine' associated, being separated from other mammalian Pneumocystis species, thereby confirming the accuracy of qPCR amplicon for Pneumocystis in dogs. Using qPCR, Pneumocystis DNA can be detected in specimens from the respiratory tract and a C-T value can be interpreted to distinguish infection versus colonization