The responses of an anaerobic microorganism, Yersinia intermedia MASE-LG-1 to individual and combined simulated Martian stresses

The limits of life of aerobic microorganisms are well understood, but the responses of anaerobic microorganisms to individual and combined extreme stressors are less well known. Motivated by an interest in understanding the survivability of anaerobic microorganisms under Martian conditions, we investigated the responses of a new isolate, Yersinia intermedia MASE-LG-1 to individual and combined stresses associated with the Martian surface. This organism belongs to an adaptable and persistent genus of anaerobic microorganisms found in many environments worldwide. The effects of desiccation, low pressure, ionizing radiation, varying temperature, osmotic pressure, and oxidizing chemical compounds were investigated. The strain showed a high tolerance to desiccation, with a decline of survivability by four orders of magnitude during a storage time of 85 days. Exposure to X-rays resulted in dose-dependent inactivation for exposure up to 600 Gy while applied doses above 750 Gy led to complete inactivation. The effects of the combination of desiccation and irradiation were additive and the survivability was influenced by the order in which they were imposed. Ionizing irradiation and subsequent desiccation was more deleterious than vice versa. By contrast, the presence of perchlorates was not found to significantly affect the survival of the Yersinia strain after ionizing radiation. These data show that the organism has the capacity to survive and grow in physical and chemical stresses, imposed individually or in combination that are associated with Martian environment. Eventually it lost its viability showing that many of the most adaptable anaerobic organisms on Earth would be killed on Mars today

Contrôle de l'eau dans les petites agglomérations : des modalités à réviser ?

L'eau de 30 communes rurales ne disposant pas de traitement de désinfection a été analysée pendant 18 semaines. Il est montré une très grande variabilité de la qualité de l'eau d'une semaine à l'autre. Une filtration de 300 ml a été menée en parallèle à celle de 100 ml. Les résultats des deux analyses sont proches lorsque l'eau est habituellement conforme sur 100 ml. Ils sont très différents lorsque l'eau est de qualité variable sur 100 ml. Les indicateurs bactériens (numération totale, coliformes totaux et fécaux, streptocoques et spores de bactéries anaérobies) présentent des résultats concordants et donc redondants. Lorsque l'eau est de qualité variable, la fréquence analyses bactériologiques par an n'est pas suffisante pour garantir la qualité Dans ce cas recommencer l'analyse après un résultat contaminé n'apporte pas d'information supplémentaire. L'amélioration de la ressource est alors prioritaire

Differences in the frequency and function of HHV8-specific CD8 T cells between asymptomatic HHV8 infection and Kaposi sarcoma

It is unclear how the immune response controls human herpesvirus 8 (HHV8; also known as Kaposi sarcoma-associated herpesvirus [KSHV]) replication and thereby prevents Kaposi sarcoma (KS). We compared CD8 T-cell responses to HHV8 latent (K12) and lytic (glycoprotein B, ORF6, ORF61, and ORF65) antigens in patients who spontaneously controlled the infection and in patients with posttransplantation, AIDS-related, or classical KS. We found that anti-HHV8 responses were frequent, diverse, and strongly differentiated toward an effector phenotype in patients who controlled the infection. Conversely, HHV8-specific CD8 cells were very rare in patients who progressed to KS, and were not recruited to the tumoral tissue, as visualized by in situ tetramer staining of KS biopsies. Last, HHV8-specific CD8 T cells were observed in a seronegative recipient of an HHV8infected graft who remained persistently aviremic and antibody negative, suggesting that specific cytotoxic T lymphocytes (CTLs) may provide protection from persistent HHV8 infection. These results support the crucial role of cellular immune responses in controlling HHV8 replication, in preventing malignancies in latently infected subjects, and in conferring genuine resistance to persistent infection. They may also have important implications for the design of prophylactic and therapeutic HHV8 vaccines, and for adoptive immunotherapy of KS

Paradoxical simultaneous regression and progression of lesions in a phase II study of everolimus in classic Kaposi sarcoma

International audienc

Ketosis-Prone Type 2 Diabetes Mellitus and<em> Human Herpesvirus 8 </em>Infection in Sub-Saharan Africans

Context: An atypical form of type 2 diabetes mellitus (DM-2) is revealed by ketosis (ketosis-prone type 2 diabetes mellitus), frequently occurring in individuals who are black and of African origin, and characterized by an acute onset requiring transient insulin therapy. Its sudden onset suggests precipitating factors. Objective: To investigate the putative role of human herpesvirus 8 (HHV-8) in the pathogenesis of ketosis-prone DM-2. Design, Setting, and Participants: A cross-sectional study in which antibodies were searched against latent and lytic HHV-8 antigens using immunofluorescence. The presence of HHV-8 in genomic DNA was investigated in 22 of the participants at clinical onset of diabetes. We also tested whether HHV-8 was able to infect human pancreatic β cells in culture in vitro. The study was conducted at Saint-Louis University Hospital, Paris, France, from January 2004 to July 2005. All participants were black and of African origin: 187 were consecutive diabetic patients of whom 81 had ketosis-prone DM-2 and 106 had nonketotic DM-2, and 90 individuals were nondiabetic control participants who were matched for age and sex. Main Outcome Measures: Seroprevalence of HHV-8 and percentage of patients with HHV-8 viremia at onset in ketosis-prone DM-2. Results: HHV-8 antibodies were found in 71 patients (87.7%) with ketosis-prone DM-2 vs 16 patients (15.1%) with nonketotic DM-2 (odds ratio, 39.9; 95% confidence interval, 17.1-93.4; P &lt; .001) and 36 of the control participants (40.0%) (odds ratio, 10.7; 95% confidence interval, 4.9-23.4; P &lt; .001). HHV-8 in genomic DNA was present in 6 of 13 patients with ketosis-prone DM-2 tested at acute onset and in 0 of 9 patients with nonketotic DM-2. HHV-8 proteins were present in human islet cells that were cultured for 4 days in the presence of HHV-8. Conclusions: In this preliminary cross-sectional study, the presence of HHV-8 antibodies was associated with ketosis-prone DM-2 in patients of sub-Saharan African origin. Longitudinal studies are required to understand the clinical significance of these findings. \ua92008 American Medical Association. All rights reserved