Mutation on lysX from Mycobacterium avium hominissuis impacts the host–pathogen interaction and virulence phenotype

The lysX gene from Mycobacterium avium hominissuis (MAH) is not only involved in cationic antimicrobial resistance but also regulates metabolic activity. An MAH lysX deficient mutant was shown to exhibit a metabolic shift at the extracellular state preadapting the bacteria to the conditions inside host-cells. It further showed stronger growth in human monocytes. In the present study, the LysX activity on host–pathogen interactions were analyzed. The lysX mutant from MAH proved to be more sensitive toward host-mediated stresses such as reactive oxygen species. Further, the lysX mutant exhibited increased inflammatory response in PBMC and multinucleated giant cell (MGC) formation in human macrophages during infection studies. Coincidentally, the lysX mutant strain revealed to be more reproductive in the Galleria mellonella infection model. Together, these data demonstrate that LysX plays a role in regulating the bacillary load in host organisms and the lack of lysX gene facilitates MAH adaptation to intracellular host-habitat, thereby suggesting an essential role of LysX in the modulation of host–pathogen interaction.Peer Reviewe

Evaluation des activités polyphénoloxydases, peroxydases et l’accumulation des composés phénoliques dans la résistance du manioc stimulé au Benzo (1,2,3) thiadiazol-7-carbothionic acid-s-méthyl ester vis-à-vis de Colletotrichum gloeosporioides Penz

Le manioc (Manihot esculenta Crantz) est une plante pluriannuelle cultivée dans les régions tropicales de la plupart des pays d’Afrique, d’Asie et d’Amérique Latine. Il contribue fortement à la sécurité alimentaire. L’objectif de cette étude est d’analyser le comportement des polyphénoloxydases (PPO), de la peroxydase (POX) et des composés phénoliques chez trois variétés de manioc au cours de leur induction au Benzo (1,2,3) thiadiazol-7-carbothionic acid-s-methyl ester (BTH) vis-à-vis de C. gloeosporioides. L’induction de résistance a été évaluée par des PPO , de la POX et de la teneur en composés phénoliques totaux solubles accumulés avant et après l’inoculation (I) par C. gloeosporioides, la stimulation (St) par BTH et de la stimulation suivie de l’inoculation (St+I). Avec les différents traitements, on note une augmentation progressive et significative (p<0,05) de l’activité de ces enzymes et des teneurs en phénols dans les feuilles et les tiges chez les trois variétés. Ces résultats montrent bien que le BTH stimule les mécanismes de défenses des plantes de manioc, bien que ces mécanismes diffèrent en fonction des variétés.   English title: Evaluation of polyphenoloxidase and peroxidase activities and accumulation of phenolic compounds in the resistance of stimulated cassava to Benzo (1,2,3) thiadiazol-7-carbothionic acid-s-methyl ester against Colletotrichum gloeosporioides Penz. Cassava (Manihot esculenta Crantz) is a perennia plant cultivated in the tropical regions of most countries in Africa, Asia and Latin America. It contributes strongly to food security. The aim of this study was to analyze the behavior of polyphenoloxidases (PPO), peroxidase (POX) and phenolic compounds in three cassava varieties during their induction to Benzo (1,2,3) thiadiazol-7-carbothionic acid-s-methyl ester (BTH) against C. gloeosporioides. Resistance induction was evaluated by PPO, POX and total soluble phenolic compounds content accumulated before and after inoculation (I) with C. gloeosporioides, stimulation (St) with BTH and stimulation followed by inoculation (St+I). With the different treatments, there was a progressive and significant (p<0.05) increase in the activity of these enzymes and in the phenol contents in the leaves and stems of the three varieties. These results show that BTH stimulates the defense mechanisms of cassava plants, although these mechanisms differ according to the varieties. &nbsp

Redox electrocatalysis of floating nanoparticles: determining electrocatalytic properties without the influence of solid supports

peer-reviewedRedox electrocatalysis (catalysis of electron transfer reactions by floating conductive particles) is discussed from the point-of-view of Fermi level equilibration, and an overall theoretical framework is given. Examples of redox electrocatalysis in solution, in bipolar configuration and at liquid-liquid interfaces are provided, highlighting that bipolar and liquid-liquid interfacial systems allow the study of the electrocatalytic properties of particles without effects from the support, but only liquid-liquid interfaces allow measurement of the electrocatalytic current directly. Additionally, photo-induced redox electrocatalysis will be of interest, for example to achieve water splittin

Coronary Spasm: Ethnic and Sex Differences

Coronary spasm (CS), which may occur at the epicardial (focal or diffuse spasm) and/or microvascular (microvascular spasm) level, is a well-established cause of myocardial ischaemia, in particular in patients with anginal chest pain despite unobstructed coronary arteries. The diagnosis of CS can be confirmed during coronary angiography by an additional provocation test with vasoactive substances such as acetylcholine. Due to partially inconsistent data from large clinical studies, especially between Asian and white CS patients, ethnic differences concerning the prevalence and angiographic patterns of CS seem to exist. Furthermore, several studies in patients with coronary vasomotor disorders pointed towards differences among male and female CS patients. This article gives an overview of ethnic- and sex-related differences in patients with CS

A self-assembled organic/metal junction for water photo-oxidation

We report the in situ self-assembly of TTF, TTF ·+ , and BF 4 - or PF 6 - into p-type semiconductors on the surface of Pt microparticles dispersed in water/acetonitrile mixtures. The visible light photoactivation of these self-assemblies leads to water oxidation forming O 2 and H + , with an efficiency of 100% with respect to the initial concentration of TTF ·+ . TTF ·+ is then completely reduced to TTF upon photoreduction with water. The Pt microparticles act as floating microelectrodes whose Fermi level is imposed by the different redox species in solution; here predominantly TTF, TTF ·+ , and HTTF + , which furthermore showed no signs of decomposition in solution.Fil: Olaya, Astrid J.. Swiss Federal Institute Of Technology Epfl; SuizaFil: Omatsu, Terumasa. Kyoto Institute Of Technology; JapónFil: Hidalgo-Acosta, Jonnathan C.. Swiss Federal Institute Of Technology Epfl; SuizaFil: Riva, Julieta Soledad. Swiss Federal Institute Of Technology Epfl; Suiza. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bassetto, Victor Costa. Swiss Federal Institute Of Technology Epfl; SuizaFil: Gasilova, Natalia. Swiss Federal Institute Of Technology Epfl; SuizaFil: Girault, Hubert. Swiss Federal Institute Of Technology Epfl; Suiz

Serotonin receptor type 3 antagonists improve obesity-associated fatty liver disease in mice

ABSTRACT Obesity is a major cause for nonalcoholic fatty liver disease (NAFLD). Previous studies suggested that alterations in intestinal motility and permeability contribute to the development of NAFLD. Serotonin and serotonin receptor type 3 (5-HT 3 R) are key factors in the regulation of intestinal motility and permeability. Therefore, we studied the effect of the 5-HT 3 R antagonists tropisetron and palonosetron on the development of NA-FLD in leptin-deficient obese mice. Four-week-old ob/ob mice and lean controls were treated for 6 weeks orally with tropisetron or palonosetron at 0.2 mg/kg per day. We determined markers of liver damage and inflammation, portal endotoxin levels, and duodenal concentrations of serotonin, serotoninreuptake transporter (SERT), occludin, and claudin-1. Tropisetron treatment significantly reduced liver fat content (Ϫ29%), liver inflammation (Ϫ56%), and liver cell necrosis (Ϫ59%) in ob/ob mice. The beneficial effects of tropisetron were accompanied by a decrease in plasma alanine aminotransferase and portal vein plasma endotoxin levels, an attenuation of enhanced MyD88 and tumor necrosis factor-␣ mRNA expression in the liver, and an increase of tight junction proteins in the duodenum. Tropisetron treatment also caused a reduction of elevated serotonin levels and an increase of SERT in the duodenum of ob/ob mice. Palonosetron had similar effects as tropisetron with regard to the reduction of liver fat and other parameters. Tropisetron and palonosetron are effective in attenuating NAFLD in a genetic mouse model of obesity. The effect involves the intestinal nervous system, resulting in a reduction of endotoxin influx into the liver and subsequently of liver inflammation and fat accumulation

Ultrafast Population Dynamics of Surface-Active Dyes during Electrochemically Controlled Ion Transfer across a Liquid|Liquid Interface

We present for the first time experimental measurements on the ultrafast population dynamics of the model surface-active dye methyl orange (MO) during its ion transfer across the water|1,2-dichloroethane interface by using time-resolved surface second harmonic generation (TR-SSHG). The interfacial dynamics reveals that the population of MO relaxes to the ground state within 160 fs without any significant contribution of the molecular reorientation. It is concluded that the MO transfer across the interface considerably affects the population of MO at the interface but has no effect on the dynamics of the molecule itself

Genetic diversification of persistent Mycobacterium abscessus within cystic fibrosis patients

Mycobacterium (M.) abscessus infections in Cystic Fibrosis (CF) patients cause a deterioration of lung function. Treatment of these multidrug-resistant pathogens is associated with severe side-effects, while frequently unsuccessful. Insight on M. abscessus genomic evolvement during chronic lung infection would be beneficial for improving treatment strategies. A longitudinal study enrolling 42 CF patients was performed at a CF center in Berlin, Germany, to elaborate phylogeny and genomic diversification of in-patient M. abscessus. Eleven of the 42 CF patients were infected with M. abscessus. Five of these 11 patients were infected with global human-transmissible M. abscessus cluster strains. Phylogenetic analysis of 88 genomes from isolates of the 11 patients excluded occurrence of M. abscessus transmission among members of the study group. Genome sequencing and variant analysis of 30 isolates from 11 serial respiratory samples collected over 4.5 years from a chronically infected patient demonstrated accumulation of gene mutations. In total, 53 genes exhibiting non-synonymous variations were identified. Enrichment analysis emphasized genes involved in synthesis of glycopeptidolipids, genes from the embABC (arabinosyltransferase) operon, betA (glucose-methanol-choline oxidoreductase) and choD (cholesterol oxidase). Genetic diversity evolved in a variety of virulence- and resistance-associated genes. The strategy of M. abscessus populations in chronic lung infection is not clonal expansion of dominant variants, but to sustain simultaneously a wide range of genetic variants facilitating adaptation of the population to changing living conditions in the lung. Genomic diversification during chronic infection requires increased attention when new control strategies against M. abscessus infections are explored.Peer Reviewe

Voltammetric determination of extreme standard Gibbs ion transfer energy

A voltammetric methodology to determine the standard Gibbs energy of transfer of highly hydrophobic and hydrophilic ions has been developed. The electrochemical cell used includes a water|1,2-dichloroethane micro-interface supported on a microhole in a thin polymer film separating an electrolyte-free aqueous phase and an organic phase with an electrolyte at low concentrations. The limiting current and the half-wave potential of these organic ions were determined by fitting the initial part of the ion transfer wave. The methodology was validated using ions with known thermodynamic data, and applied to very hydrophobic and very hydrophilic ions that usually cannot be observed within the potential window