Participatory community action research in homeless shelters: Outcomes for shelter residents and service-learning research assistants.

The article reports empirical outcomes of an ongoing transdisciplinary participatory community action research project that implements behavioral activation in homeless shelters. The overall goal of this Project is twofold: (1) to improve psychosocial functioning of shelter residents and enhance their opportunities to overcome homelessness; and (2) to enhance civic development of service-learning students who assist in Project implementation. Two studies are reported, representing these goals. Study 1 found that residents of a men's shelter (n = 892), women's shelter (n = 433), and transitional housing (n = 40) perceived behavioral activation sessions as immediately beneficial (i.e., important, meaningful, worthy of repeating, and enjoyable), and over the course of shelter stay, they perceived behavioral activation as contributing to their hope, empowerment/self-sufficiency, quality of life, purpose/meaning in life, wellbeing, social support, shelter social climate, and relationships with staff. Quantitative findings are supported by qualitative data (comments by residents on forms). Study 2, which replicates and extends past research on civic-development in service-learning students, used a new quasi-experimental design to compare service-learning students (n = 41) in an interdisciplinary course on homelessness versus non-service-learning students (n = 16) in a psychology course. Service-learning students showed pre- to post-semester improvements in community service self-efficacy, decreases in stigmatizing attitudes, and increases in awareness of privilege and oppression, but students not engaged in service-learning did not show these civic-related changes. These quantitative results are supported by qualitative data (written reflections by students). Results and implications are discussed within the context of the concept of psychopolitical validity.

N-acyl homoserine lactones in diverse Pectobacterium and Dickeya plant pathogens: diversity, abundance, and involvement in virulence.

Soft-rot bacteria Pectobacterium and Dickeya use N-acyl homoserine lactones (NAHSLs) as diffusible signals for coordinating quorum sensing communication. The production of NAHSLs was investigated in a set of reference strains and recently-collected isolates, which belong to six species and share the ability to infect the potato host plant. All the pathogens produced different NAHSLs, among which the 3-oxo-hexanoyl- and the 3-oxo-octanoyl-L-homoserine lactones represent at least 90% of total produced NAHSL-amounts. The level of NAHSLs varied from 0.6 to 2 pg/cfu. The involvement of NAHSLs in tuber maceration was investigated by electroporating a quorum quenching vector in each of the bacterial pathogen strains. All the NAHSL-lactonase expressing strains produced a lower amount of NAHSLs as compared to those harboring the empty vector. Moreover, all except Dickeya dadantii 3937 induced a lower level of symptoms in potato tuber assay. Noticeably, aggressiveness appeared to be independent of both nature and amount of produced signals. This work highlights that quorum sensing similarly contributed to virulence in most of the tested Pectobacterium and Dickeya, even the strains had been isolated recently or during the past decades. Thus, these key regulatory-molecules appear as credible targets for developing anti-virulence strategies against these plant pathogens.

Effects of a skin neuropeptide (substance p) on cutaneous microflora.

BACKGROUND: Skin is the largest human neuroendocrine organ and hosts the second most numerous microbial population but the interaction of skin neuropeptides with the microflora has never been investigated. We studied the effect of Substance P (SP), a peptide released by nerve endings in the skin on bacterial virulence. METHODOLOGY/PRINCIPAL FINDINGS: Bacillus cereus, a member of the skin transient microflora, was used as a model. Exposure to SP strongly stimulated the cytotoxicity of B. cereus (+553±3% with SP 10(-6) M) and this effect was rapid (<5 min). Infection of keratinocytes with SP treated B. cereus led to a rise in caspase1 and morphological alterations of the actin cytoskeleton. Secretome analysis revealed that SP stimulated the release of collagenase and superoxide dismutase. Moreover, we also noted a shift in the surface polarity of the bacteria linked to a peel-off of the S-layer and the release of S-layer proteins. Meanwhile, the biofilm formation activity of B. cereus was increased. The Thermo unstable ribosomal Elongation factor (Ef-Tu) was identified as the SP binding site in B. cereus. Other Gram positive skin bacteria, namely Staphylococcus aureus and Staphylococcus epidermidis also reacted to SP by an increase of virulence. Thermal water from Uriage-les-Bains and an artificial polysaccharide (Teflose®) were capable to antagonize the effect of SP on bacterial virulence. CONCLUSIONS/SIGNIFICANCE: SP is released in sweat during stress and is known to be involved in the pathogenesis of numerous skin diseases through neurogenic inflammation. Our study suggests that a direct effect of SP on the skin microbiote should be another mechanism.