In a previous clinical study, a probiotic formulation (PF) consisting of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 (PF) decreased stress-induced gastrointestinal discomfort. Emerging evidence of a role for gut microbiota on central nervous system functions therefore suggests that oral intake of probiotics may have beneficial consequences on mood and psychological distress. The aim of the present study was to investigate the anxiolytic-like activity of PF in rats, and its possible effects on anxiety, depression, stress and coping strategies in healthy human volunteers. In the preclinical study, rats were daily administered PF for 2 weeks and subsequently tested in the conditioned defensive burying test, a screening model for anti-anxiety agents. In the clinical trial, volunteers participated in a double-blind, placebo-controlled, randomised parallel group study with PF administered for 30 d and assessed with the Hopkins Symptom Checklist (HSCL-90), the Hospital Anxiety and Depression Scale (HADS), the Perceived Stress Scale, the Coping Checklist (CCL) and 24 h urinary free cortisol (UFC). Daily subchronic administration of PF significantly reduced anxiety-like behaviour in rats (P,0·05) and alleviated psychological distress in volunteers, as measured particularly by the HSCL-90 scale (global severity index, P, 0·05; somatisation, P, 0·05; depression, P, 0·05; and anger-hostility, P,0·05), the HADS (HADS global score, P, 0·05; and HADSanxiety, P,0·06), and by the CCL (problem solving, P, 0·05) and the UFC level (P,0·05). L. helveticus R0052 and B. longum R0175 taken in combination display anxiolytic-like activity in rats and beneficial psychological effects in healthy human volunteers.

I n a recent clinical study, we demonstrated in the general population that Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 (PF) taken in combination for 30 days decreased the global scores of hospital anxiety and depression scale (HADs), and the global severity index of the Hopkins symptoms checklist (HSCL-90), due to the decrease of the sub-scores of somatization, depression and angerhostility spheres. Therefore, oral intake of PF showed beneficial effects on anxiety and depression related behaviors in human volunteers. From there, it is interesting to focus on the role of this probiotic formulation in the subjects with the lowest urinary free cortisol levels at baseline. This addendum presents a secondary analysis of the effects of PF in a subpopulation of 25 subjects with urinary free cortisol (UFC) levels less than 50 ng/ml at baseline, on psychological distress based on the percentage of change of the perceived stress scale (PSs), the HADs and the HSCL-90 scores between baseline and follow-up. The data show that PF improves the same scores as in the general population (the HADs global score, the global severity index of the HSCL-90 and three of its sub-scores, i.e., somatization, depression and anger-hostility), as well as the PSs score and three other subscores of the HSCL-90, i.e., "obsessive compulsive," "anxiety" and "paranoidideation." Moreover, in the HSCL-90, Beneficial psychological effects of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in healthy human volunteers

Lymphocyte polyclonal activation is a generalized mechanism of immune evasion among pathogens. In a mouse model of Trypanosoma cruzi infection (American trypanosomiasis), reduced levels of polyclonal lymphocyte responses correlate with resistance to infection and cardiopathy. We report here the characterization of a parasite protein with B-cell mitogenic properties in culture supernatants of infective forms, the cloning of the corresponding gene and the analysis of the biological properties of its product. We characterized the protein as a co-factor-independent proline racemase, and show that its expression as a cytoplasmic and/or membrane-associated protein is life-stage specific. Inhibition studies indicate that availability of the racemase active site is necessary for mitogenic activity. This is the first report to our knowledge of a eukaryotic amino acid racemase gene. Our findings have potential consequences for the development of new immune therapies and drug design against pathogens.