French Institute of Health and Medical Research

About: French Institute of Health and Medical Research is a government organization based out in Paris, France. It is known for research contribution in the topics: Population & Receptor. The organization has 109367 authors who have published 174236 publications receiving 8365503 citations.

The Listeria transcriptional landscape from saprophytism to virulence

Abstract: The bacterium Listeria monocytogenes is ubiquitous in the environment and can lead to severe food-borne infections. It has recently emerged as a multifaceted model in pathogenesis. However, how this bacterium switches from a saprophyte to a pathogen is largely unknown. Here, using tiling arrays and RNAs from wild-type and mutant bacteria grown in vitro, ex vivo and in vivo, we have analysed the transcription of its entire genome. We provide the complete Listeria operon map and have uncovered far more diverse types of RNAs than expected: in addition to 50 small RNAs (<500 nucleotides), at least two of which are involved in virulence in mice, we have identified antisense RNAs covering several open-reading frames and long overlapping 5' and 3' untranslated regions. We discovered that riboswitches can act as terminators for upstream genes. When Listeria reaches the host intestinal lumen, an extensive transcriptional reshaping occurs with a SigB-mediated activation of virulence genes. In contrast, in the blood, PrfA controls transcription of virulence genes. Remarkably, several non-coding RNAs absent in the non-pathogenic species Listeria innocua exhibit the same expression patterns as the virulence genes. Together, our data unravel successive and coordinated global transcriptional changes during infection and point to previously unknown regulatory mechanisms in bacteria.

Meat, Fish, and Colorectal Cancer Risk: The European Prospective Investigation into Cancer and Nutrition

Abstract: Background: Current evidence suggests that high red meat intake is associated with increased colorectal cancer risk. High fi sh intake may be associated with a decreased risk, but the existing evidence is less convincing. Methods: We prospectively followed 478 040 men and women from 10 European countries who were free of cancer at enrollment between 1992 and 1998. Information on diet and lifestyle was collected at baseline. After a mean follow-up of 4.8 years, 1329 incident colorectal cancers were documented. We examined the relationship between intakes of red and processed meat, poultry, and fi sh and colorectal cancer risk using a proportional hazards model adjusted for age, sex, energy (nonfat and fat sources), height, weight, workrelated physical activity, smoking status, dietary fi ber and folate, and alcohol consumption, stratifi ed by center. A calibration substudy based on 36 994 subjects was used to correct hazard ratios (HRs) and 95% confi dence intervals (CIs) for diet measurement errors. All statistical tests were two-sided. Results: Colorectal cancer risk was positively associated with intake of red and processed meat (highest [>160 g/day] versus lowest [ 80 g/day versus <10 g/day, HR = 0.69, 95 % CI = 0.54 to 0.88; P trend <.001), but was not related to poultry intake. Correcting for measurement error strengthened the associations between colorectal cancer and red and processed meat intake (per 100-g increase HR = 1.25, 95% CI =1.09 to 1.41, P trend = .001 and HR = 1.55, 95% CI = 1.19 to 2.02, P trend = .001 before and after calibration, respectively) and for fi sh (per 100 g increase HR = 0.70, 95% CI = 0.57 to 0.87, P trend <.001 and HR = 0.46, 95% CI = 0.27 to 0.77, P trend = .003; before and after correction, respectively). In this study population, the absolute risk of development of colorectal cancer within 10 years for a study subject aged 50 years was 1.71% for the highest category of red and processed meat intake and 1.28% for the lowest category of intake and was 1.86% for subjects in the lowest category of fi sh intake and 1.28% for subjects in the highest category of fi sh intake. Conclusions: Our data confi rm that colorectal cancer risk is positively associated with high consumption of red and processed meat and support an inverse association with fi sh intake. [J Natl Cancer Inst 2005;97:906–16]