Current studies have indicated the utility of photodynamic therapy using porphyrins in the treatment of bacterial infections. Photoactivation of porphyrins results in the production of singlet oxygen ((1)O(2)) that damages biomolecules associated with cells and biofilms, e.g., proteins, polysaccharides, and DNA. The effect of a cationic porphryin on P. aeruginosa PAO1 biofilms was assessed by exposing static biofilms to 5,10,15,20-tetrakis(1-methyl-pyridino)-21H,23H-porphine, tetra-p-tosylate salt (TMP) followed by irradiation. Biofilms were visualized using confocal laser scanning microscopy (CLSM) and cell viability determined using the LIVE/DEAD BacLight viability assay and standard plate counts. At a concentration of 100 μM TMP, there was substantial killing of P. aeruginosa PAO1 wild-type and pqsA mutant biofilms with little disruption of the biofilm matrix or structure. Exposure to 225 μM TMP resulted in almost complete killing as well as the detachment of wild-type PAO1 biofilms. In contrast, pqsA mutant biofilms that contain less extracellular DNA remained intact. Standard plate counts of cells recovered from attached biofilms revealed a 4.1-log(10) and a 3.9-log(10) reduction in viable cells of wild-type PAO1 and pqsA mutant strains, respectively. Our results suggest that the action of photoactivated TMP on P. aeruginosa biofilms is two-fold: direct killing of individual cells within biofilms and detachment of the biofilm from the substratum. There was no evidence of porphyrin toxicity in the absence of light; however, biofilms pretreated with TMP without photoactivation were substantially more sensitive to tobramycin than untreated biofilms.
Twitching motility allows Pseudomonas aeruginosa to respond to stimuli by extending and retracting its type IV pili (TFP). PilJ is a protein necessary for this surface-associated twitching motility and bears high sequence identity with Escherichia coli methyl-accepting chemotaxis proteins (MCP). Here, we report that whereas wild-type P. aeruginosa PAO1 cells have extended pili at a single pole, pilJ mutant cells have shortened pili often at both poles despite normal levels of pilin accumulation, suggesting that PilJ is required for full TFP assembly/extension. Using yellow fluorescent protein fusions (pilJ-yfp), both plasmid born and in-frame chromosomal constructs, we determined that PilJ localizes to both poles of the cell. Overexpression of pilJ-yfp resulted in the protein accumulating between the poles.
Increasingly men are becoming widowed in later life due in part to a longer life expectancy. Social networks and social support are thought to help buffer the negative consequences of such later life transitions. This paper explores the personal communities of a group of older men experiencing widowhood. Qualitative in‐depth interviews were conducted, September 2013–February 2014, with seven older widowers, 71–89 years of age, in North Staffordshire, UK. Interviews included personal community diagrams to identify the structure of the older men's social relationships. Data analysis comprised thematic analysis of interview transcripts and content analysis of personal community diagrams. Three overarching themes were identified from the interview data: “Personal identity and resilience assist transition,” “Continuity in personal communities provides stability” and “Changes in social relationships and practices facilitate adaptation.” The study identified three types of personal community among the older widowers, comprising different combinations of family, friends and others. The findings illustrate that some older widowers have very restricted personal communities which puts them at greater risk of loneliness and social isolation. The social needs of long‐term carers should be addressed as isolation and loneliness can begin long before the death of a spouse. It is important to consider gender differences and preferences when designing interventions for older people in order to promote engagement, social inclusion and well‐being.
Remembering the past, looking to the future : Christmas as a symbol of change in later life widowhood Remembering the past, looking to the future: Christmas as a symbol of change in later life widowhood TRACY COLLINS* ABSTRACTMany older women experience the loss of a spouse or partner in later life. This paper explores older women's experiences of Christmas in order to locate process and meaning in relation to the transition of later life widowhood. Drawing on longitudinal data, derived from three in-depth interviews conducted over months with older widows, this paper presents a number of themes from the women's accounts of their Christmas celebrations and their Christmas cards. The importance of continuity, social relations and autonomy is situated in three emergent themes: 'Family, intergenerational ties and tradition', 'Friendships, organisational ties and reciprocity' and 'Personal continuity and activation'. The significance of discontinuity, change and mediation is illustrated through three emergent themes: 'Christmas as a catalyst for change', 'We are all widows' and 'Negotiating change with others'. The findings, including the positive aspects of continuity and discontinuity, demonstrate that Christmas is a potent symbol of both personal and social transformation during later life widowhood, and that the management of transition incorporates not only social relations, but also personal agency and flexibility. This paper further challenges the predominantly negative stereotype of older widows and illustrates their resilience and growth in the later stages of life.
In Europe, cremation as a burial practice is often associated with the Bronze Age, but examples of cremated human remains are in fact known from the Palaeolithic onwards. Unlike conventional inhumation, cremation destroys most of the evidence we can use to reconstruct the biography of the buried individual. Remarkably, in Ireland, cremation is used for the earliest recorded human burial and grave assemblage (7530–7320 bc) located on the banks of the River Shannon, at Hermitage, County Limerick. While we are unable to reconstruct in any great detail the biography of this individual, we have examined the biography of a polished stone adzehead interred with their remains. To our knowledge, this adze represents the earliest securely dated polished axe or adze in Europe. Microscopic analysis reveals that the adze was commissioned for burial, with a short duration of use indicating its employment in funerary rites. Before its deposition into the grave it was intentionally blunted, effectively ending its use-life: analogous to the death of the individual it accompanied. The microwear traces on this adze thus provide a rare insight into early Mesolithic hunter-gatherer belief systems surrounding death, whereby tools played an integral part in mortuary rites and were seen as fundamental pieces of equipment for a successful afterlife.
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