Cyclic di-GMP-dependent Signaling Pathways in the Pathogenic Firmicute Listeria Monocytogenes

We characterized key components and major targets of the c-di-GMP signaling pathways in the foodborne pathogen Listeria monocytogenes, identified a new c-di-GMP-inducible exopolysaccharide responsible for motility inhibition, cell aggregation, and enhanced tolerance to disinfectants and desiccation, and provided first insights into the role of c-di-GMP signaling in listerial virulence. Genome-wide genetic and biochemical analyses of c-di-GMP signaling pathways revealed that L. monocytogenes has three GGDEF domain proteins, DgcA (Lmo1911), DgcB (Lmo1912) and DgcC (Lmo2174), that possess diguanylate cyclase activity, and three EAL domain proteins, PdeB (Lmo0131), PdeC (Lmo1914) and PdeD (Lmo0111), that possess c-di-GMP phosphodiesterase activity. Deletion of all phosphodiesterase genes (ΔpdeB/C/D) or expression of a heterologous diguanylate cyclase stimulated production of a previously unknown exopolysaccharide. The synthesis of this exopolysaccharide was attributed to the pssA-E (lmo0527-0531) gene cluster. The last gene of the cluster encodes the fourth listerial GGDEF domain protein, PssE, that functions as an I-site c-di-GMP receptor essential for exopolysaccharide synthesis. The c-di-GMP-inducible exopolysaccharide causes cell aggregation in minimal medium and impairs bacterial migration in semi-solid agar, however, it does not promote biofilm formation on abiotic surfaces. The exopolysaccharide also greatly enhances bacterial tolerance to commonly used disinfectants as well as desiccation, which may contribute to survival of L. monocytogenes on contaminated food products and in food-processing facilities. The exopolysaccharide and another, as yet unknown c-di-GMP-dependent target, drastically decrease listerial invasiveness in enterocytes in vitro, and lower pathogen load in the liver and gallbladder of mice infected via an oral route, which suggests that elevated c-di-GMP levels play an overall negative role in listerial virulence

Resolving sea ice dynamics in the north-western Ross Sea during the last 2.6 ka: From seasonal to millennial timescales

12 months embargo applie

Respir Res

Background: Sexual function is often affected in patients suffering from chronic diseases especially chronic obstructive pulmonary disease (COPD). However, the effect of COPD on sexual satisfaction is underappreciated in clinical practice. The aim of this study is to evaluate the impact of COPD on patient’s sexuality and the explanatory variables of sexual dissatisfaction. Methods: Questionnaires were emailed to participants and they submitted their responses on the Santé Respiratoire France website. Data about sexual well-being (Arizona Sexual Experience Scale, ASEX), Quality of life (VQ11), anxiety, depression (Hospitalized anxiety and depression, HAD) and self-declared COPD grade were collected. Results: Seven hundred and fifty one subjects were included and were characterized as follows: women—51%, mean age—61 years, in a couple—62% and 70%—retired. Every grade of COPD was represented. Out of 751 participants, 301 participants (40%) had no sexual activity and 450 (60%) had sexual activity. From the 450 participants, 60% needed to change their sexual life because of their disease (rhythm, frequency and position). Subjects often used medications to improve sexual performance (43% used short-acting bronchodilator and 13% -specific erectile dysfunction drugs). ASEX questionnaire confirmed patients’ dissatisfaction (diminution of sexual appetite for 68% and sexual desire for 60%) because of breathlessness and fatigue. Eighty one percent of the responders had an altered quality of life (VQ11 mean score 35) and frequent suspected anxiety or depression (HAD mean score 10.8). Ninety percent declared that sexual dysfunction had never been discussed by their doctors, while 36% of patients would have preferred to undergo a specialized consultation. Conclusion: Sexual dysfunction is frequent among COPD patients and leads to an altered well-being, however being a cultural taboo, it remains frequently neglected. Sexual guidance should be a part of patient’s consultations improve quality of sexual life. © 2020, The Author(s)