Search results for "Arid"
showing 10 items of 1382 documents
Klebsiella pneumoniae Lipopolysaccharides Serotype O2afg Induce Poor Inflammatory Immune Responses Ex Vivo
2021
Currently, Klebsiella pneumoniae is a pathogen of clinical relevance due to its plastic ability of acquiring resistance genes to multiple antibiotics. During K. pneumoniae infections, lipopolysaccharides (LPS) play an ambiguous role as they both activate immune responses but can also play a role in immune evasion. The LPS O2a and LPS O2afg serotypes are prevalent in most multidrug resistant K. pneumoniae strains. Thus, we sought to understand if those two particular LPS serotypes were involved in a mechanism of immune evasion. We have extracted LPS (serotypes O1, O2a and O2afg) from K. pneumoniae strains and, using human monocytes ex vivo, we assessed the ability of those LPS antigens to in…
Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages
2018
Background Klebsiella oxytoca DSM 29614 - isolated from acid mine drainages - grows anaerobically using Fe(III)-citrate as sole carbon and energy source, unlike other enterobacteria and K. oxytoca clinical isolates. The DSM 29614 strain is multi metal resistant and produces metal nanoparticles that are embedded in its very peculiar capsular exopolysaccharide. These metal nanoparticles were effective as antimicrobial and anticancer compounds, chemical catalysts and nano-fertilizers. Results The DSM 29614 strain genome was sequenced and analysed by a combination of in silico procedures. Comparative genomics, performed between 85 K. oxytoca representatives and K. oxytoca DSM 29614, revealed th…
Broad Prebiotic Potential of Non-starch Polysaccharides from Oats (Avena sativa L.): an in vitro Study
2018
Abstract Prebiotics inducing the growth or activity of beneficial intestinal bacteria – probiotics producing short-chain fatty acids (SCFA) have lately received wide recognition for their beneficial influence on host intestinal microbiota and metabolic health. Some non-starch polysaccharides (NSP) are defined as prebiotics and oats being one of richest sources of NSP in grains are considered as potentially having prebiotic effect. However, information on fermentation of specific NSP of oats is limited. Moreover, bacterial cross-feeding interactions in which fermentation of prebiotics is involved is poorly characterized. Here, we report the exploration of new candidates for the syntrophic ba…
The LuxR Regulators PcoR and RfiA Co-regulate Antimicrobial Peptide and Alginate Production in Pseudomonas corrugata
2018
Cyclic lipopeptides (CLPs) are considered as some of the most important secondary metabolites in different plant-associated bacteria, thanks to their antimicrobial, cytotoxic, and surfactant properties. In this study, our aim was to investigate the role of the Quorum Sensing (QS) system, PcoI/PcoR, and the LuxR-type transcriptional regulator RfiA in CLP production in the phytopatogenic bacterium, Pseudomonas corrugata based on our previous work where we reported that the pcoR and rfiA mutants were devoid of the CLPs cormycin and corpeptin production. Due to the close genetic link between the QS system and the RfiA (rfiA is co-transcribed with pcoI), it was difficult to ascertain the specifi…
Difference in Markers of Microbial Translocation and Cell Apoptosis in HIV Monoinfected and HIV/HCV Coinfected Patients
2019
Abstract Immune activation in human immunodeficiency virus (HIV) infection is driven by microbial translocation and in HIV patients is one of the contributors to faster progression of liver disease along with increased cell apoptosis. The aim of the study was to compare microbial translocation and apoptosis markers in HIV monoinfected and HIV/hepatitis C virus (HCV) coinfected patients, depending on HIV immune status and antiretroviral treatment (ART). We analysed data for 78 HIV monoinfected and 105 HIV/HCV coinfected patients from the Rīga East University Hospital. Lipopolysaccharide (LPS), endotoxin core antibodies (EndoCAb), cytokeratin 18 (CK18) and cyto-chrome c (Cyt-c) levels were me…
Large Blooms of Bacillales (Firmicutes) Underlie the Response to Wetting of Cyanobacterial Biocrusts at Various Stages of Maturity.
2018
ABSTRACT Biological soil crusts (biocrusts) account for a substantial portion of primary production in dryland ecosystems. They successionally mature to deliver a suite of ecosystem services, such as carbon sequestration, water retention and nutrient cycling, and climate regulation. Biocrust assemblages are extremely well adapted to survive desiccation and to rapidly take advantage of the periodic precipitation events typical of arid ecosystems. Here we focus on the wetting response of incipient cyanobacterial crusts as they mature from “light” to “dark.” We sampled a cyanobacterial biocrust chronosequence before (dry) and temporally following a controlled wetting event and used high-throug…
Long-Term in vivo Evaluation of Orthotypical and Heterotypical Bioengineered Human Corneas.
2020
Purpose: Human cornea substitutes generated by tissue engineering currently require limbal stem cells for the generation of orthotypical epithelial cell cultures. We recently reported that bioengineered corneas can be fabricated in vitro from a heterotypical source obtained from Wharton’s jelly in the human umbilical cord (HWJSC). Methods: Here, we generated a partial thickness cornea model based on plastic compression nanostructured fibrin-agarose biomaterials with cornea epithelial cells on top, as an orthotypical model (HOC), or with HWJSC, as a heterotypical model (HHC), and determined their potential in vivo usefulness by implantation in an animal model. Results: No major side effects …
Mesopolysaccharides: The extracellular surface layer of visceral organs
2020
The mesothelium is a dynamic and specialized tissue layer that covers the somatic cavities (pleural, peritoneal, and pericardial) as well as the surface of the visceral organs such as the lung, heart, liver, bowel and tunica vaginalis testis. The potential therapeutic manipulation of visceral organs has been complicated by the carbohydrate surface layer—here, called the mesopolysaccharide (MPS)—that coats the outer layer of the mesothelium. The traditional understanding of MPS structure has relied upon fixation techniques known to degrade carbohydrates. The recent development of carbohydrate-preserving fixation for high resolution imaging techniques has provided an opportunity to re-examine…
A Thermodynamic Model of Monovalent Cation Homeostasis in the Yeast Saccharomyces cerevisiae
2016
Cationic and heavy metal toxicity is involved in a substantial number of diseases in mammals and crop plants. Therefore, the understanding of tightly regulated transporter activities, as well as conceiving the interplay of regulatory mechanisms, is of substantial interest. A generalized thermodynamic description is developed for the complex interplay of the plasma membrane ion transporters, membrane potential and the consumption of energy for maintaining and restoring specific intracellular cation concentrations. This concept is applied to the homeostasis of cation concentrations in the yeast cells of S. cerevisiae. The thermodynamic approach allows to model passive ion fluxes driven by the…
Association between urticaria and nematode infections
2018
Background The association between parasites and urticaria was first suggested in the last century. A wide range, 0-75.4%, of the prevalence of parasitic infection has been reported with chronic urticaria (CU). Moreover, urticaria may be detected in patients with parasitosis. Nematodes are a type of helminth that infect hundreds of millions of people throughout the world. Objective The aim of this work was to collect and review the published studies and cases of urticaria associated with nematode infections. Methods A search of scientific literature data bases from January 1960 until May 2017 was carried out. Results Numerous nematode infections have been associated with urticaria and/or an…