Cell surface analysis of the basidiomycete yeast cryptococcus neoformans

Cell surface properties of the basidiomycete yeast Cryptococcus neoformans were investigated with a combination of novel and well proven approaches. Non-specific cell adhesion forces, as well as exposed carbohydrate and protein moieties potentially associated with specific cellular interaction, were analysed. Experimentation and analysis employed cryptococcal cells of different strains, capsular status and culture age. Investigation of cellular charge by particulate microelectrophoresis revealed encapsulated yeast forms of C. neoformans manifest a distinctive negative charge regardless of the age of cells involved; in turn, the neutral charge of acapsulate yeasts confirmed that the polysaccharide capsule, and not the cell wall, was responsible for this occurrence. Hydrophobicity was measured by MATH and HICH techniques, as well as by the attachment of polystyrene microspheres. All three techniques, where applicable, found C. neoformans yeast to be consistently hydrophilic; this state varied little regardless of strain and culture age. Cell surface carbohydrates and protein were investigated with novel fluorescent tagging protocols, flow cytometry and confocal microscopy. Cell surface carbohydrate was identified by controlled oxidation in association with biotin hydrazide and fluorescein-streptavidin tagging. Marked amounts of carbohydrate were measured and observed on the cell wall surface of cryptococcal yeasts. Furthermore, tagging of carbohydrates with selective fluorescent lectins supported the identification, measurement and observation of substantial amounts of mannose, glucose and N-acetyl-glucosamine. Cryptococcal cell surface protein was identified using sulfo-NHS-biotin with fluorescein-streptavidin, and then readily quantified by flow cytometry. Confocal imaging of surface exposed carbohydrate and protein revealed common localised areas of vivid fluorescence associated with buds, bud scars and nascent daughter cells. Carbohydrate and protein fluorescence often varied between strains, culture age and capsule status of cells examined. Finally, extension of protein tagging techniques resulted in the isolation and extraction of two biotinylated proteins from the yeast cell wall surface of an acapsulate strain of C.neoformans.

But it’s not all about the sex:mothering, normalisation and young learning disabled people

This paper is about mothering, young learning disabled people, their sexualised and relationship lives and normalisation - not through the lens of the disabled person, but via a mothers perspective and theoretical discussion. As a mother who has a learning disabled daughter, a feminist and an academic, my own mothering experience, my PhD research and social theory are woven throughout this paper with the intention of opening up debate about sex, intimacy, normalisation, and how this impacts upon young learning disabled people. I suggest that the relationship between sex, reproduction, intimacy and intellectual impairment, and a project to decipher what it means to be human, in all its dirty glory are also part of the discourse that needs to be discussed experientially and theoretically. So much so that the messy world within which we all live can be variously and differently constructed.

Disabling a family? Emotional dilemmas experienced in becoming a parent of a child with learning disabilities

Becoming the parent of a child diagnosed with learning disabilities can have a dramatic impact. Chrissie Rogers, the author of this article, is both a lecturer in education studies at Keele University and the mother of a daughter who has learning disabilities. She argues here that the pressures on mothers to produce ‘perfect’ babies and to meet all their needs are immense. These pressures arise from both internalised norms and societal expectations and, in the face of these pressures, parents may feel shock, loss and disappointment. These feelings may lead, in turn, to denial, anxiety and conflict affecting both the parents and the professionals involved with the family. Drawing on a series of in-depth interviews and personal narratives, Chrissie Rogers makes a powerful case for the importance of support, whether that support is formal or informal. She suggests that, without the right levels of support and understanding, having a child with a diagnosis of learning disability can disable the whole family.