PapRIV, a BV-2 microglial cell activating quorum sensing peptide

Quorum sensing peptides (QSPs) are bacterial peptides produced by Gram-positive bacteria to communicate with their peers in a cell-density dependent manner. These peptides do not only act as interbacterial communication signals, but can also have effects on the host. Compelling evidence demonstrates the presence of a gut-brain axis and more specifically, the role of the gut microbiota in microglial functioning. The aim of this study is to investigate microglial activating properties of a selected QSP (PapRIV) which is produced by Bacillus cereus species. PapRIV showed in vitro activating properties of BV-2 microglia cells and was able to cross the in vitro Caco-2 cell model and reach the brain. In vivo peptide presence was also demonstrated in mouse plasma. The peptide caused induction of IL-6, TNFα and ROS expression and increased the fraction of ameboid BV-2 microglia cells in an NF-κB dependent manner. Different metabolites were identified in serum, of which the main metabolite still remained active. PapRIV is thus able to cross the gastro-intestinal tract and the blood–brain barrier and shows in vitro activating properties in BV-2 microglia cells, hereby indicating a potential role of this quorum sensing peptide in gut-brain interaction

Synthetic Communities of Bacterial Endophytes to Improve the Quality and Yield of Legume Crops

Plant-associated microbiomes confer fitness advantages to the plant host by growth promotion through different mechanisms including nutrient uptake, phytohormones production, resistance to pathogens, and stress tolerance. These effects of the potentially beneficial microbes have been used in a diversity of biotechnological approaches to improve crop performance applying individual bacterial cultures. However, healthy plants host a diversity of microorganisms (microbiota). Next-generation sequencing technologies have offered insights into the relative abundances of different phylogenetic groups in a community and the metabolic and physiological potential of its members. In the last decade, researchers have started to explore the possibilities to use temporal and functional combinations of those bacteria in the form of synthetic communities. In this chapter, we review the benefits of using endophytic bacteria in legumes, the available methodological approaches to study the effects of bacterial communities, and the most recent findings using synthetic communities to improve the performance of legume crops.Instituto de Patología VegetalFil: Monteoliva, Mariela Ines. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Monteoliva, Mariela Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Estudios Agropecuarios (UDEA) ; ArgentinaFil: Valetti, Lucio. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Valetti, Lucio. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Taurian, Tania. Universidad Nacional de Río Cuarto (UNRC). Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Taurian, Tania. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Agrobiotecnológicas; ArgentinaFil: Crociara, Clara Sonia. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Crociara, Clara Sonia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Guzzo, María Carla. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Guzzo, María Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Estudios Agropecuarios (UDEA) ; Argentin

Examination of \u3cem\u3eKlebsiella pneumoniae\u3c/em\u3e 5\u27-Methylthioadenosine/S-Adenosylhomocysteine Nucleosidase and 5-Methylthioribose Kinase

Klebsiella pneumoniae is an opportunistic bacterial pathogen that is emerging as a major global threat as an infectious agent. This organism, along with many other pathogens, possesses a broad suite of antibiotic resistances that can make treatment exceedingly difficult. As such, the impetus for creating novel antibiotics is at an all-time high despite the fact that pharmaceutical investment into drug development is at an all-time low. S-adenosylmethionine (SAM) is a universally utilized metabolite involved in a wide array of biosynthetic processes, and whose products are catabolized by a different set of enzymes in mammals than used by many bacteria, protozoa, and plants. This divergence provides two specific targets for enzymatic inhibition in K. pneumoniae: 5’-Methylthioadenosine/S-adenosylhomocysteine Nucleosidase (MTN) and 5-Methylthioribose Kinase (MTRK). In order to examine the potential effects of drugs targeting these enzymes, recombinant proteins from K. pneumoniae were isolated and purified, and a profile of their respective kinetic activities were determined. The MTRK enzyme was identified as using an ordered sequential mechanism, and shows preferential binding towards substrate analogs with hydrophobic 5-alkylthio substitutions. In addition, binding affinities of transition state-analogs and novel non-nucleoside small molecule inhibitors of MTN were quantified. Finally, the effects of MTN inhibitors on K. pneumoniae whole-cell growth, and gene expression were assessed. A number of the inhibitors demonstrated strong affinities for the MTN enzyme and induced alterations in cellular growth, autoinducer response, and the expression of genes associated with virulence

Anaerobiosis of Pseudomonas aeruginosa: Implications for Treatments of Airway Infection

Pseudomonas aeruginosa, as an opportunistic pathogen, establishes a chronic infection in the respiratory track of patients suffering from pneumonia and bronchiectasis, including cystic fibrosis. Biofilm formation inside the oversecreted mucus layer lining the patient airway and production of virulence factors, a process controlled by quorum sensing, are considered to be the major virulence determinants in P. aeruginosa pathogenesis. Recently, an abnormally thickened mucus layer was proven to be anaerobic. Given the fact that currently used antibiotics are less effective under anaerobic environments, these new findings lead us to change the way we confront P. aeruginosa infection. This article reviews pathological features of patient airways that become susceptible to P. aeruginosa infection and bacterial adaptation that contributes to the prolonged survival inside the patient airway.ope

Targeting Matrix Metallopeptidase 9 (MMP-9) and Role of Quorum Sensing (QS) in Diabetic Foot Ulcers

Diabetes-related foot ulcers (DFU) are a serious public health issue, and one of the main causes of death for diabetics is foot ulcers. Matrix metalloproteinase are crucial to both the pathophysiology of wounds and the healing process. MMPs have not previously been a focus for the treatment of DFUs due to the difficulty in differentiating between active MMPs and the two catalytically inactive forms of MMPs and the clinical failure of broad-spectrum MMP inhibitors in cancer. Managing bacterial infections by focusing on this quorum sensing (QS)-regulated process different from other management strategies. Despite the fact that the medical community has a thorough grasp of diabetic foot ulcers, research is continuously being done to find the most effective treatment for this crippling condition that is also safe to provide. Diabetic foot ulcers are brought on by a variety of factors, so a combination of therapies rather than a single medication will be the most effective course of treatment. This book chapter discusses the identification of active MMP-9 as the molecular cause of the diabetic wounds’ resistance to healing as well as the unique therapeutic strategy of inhibiting this proteinase and about role of inhibiting the quorum sensing (QS) system in the treatment of diabetic foot ulcer

Molecular Characterisation of Cultivation Processes - Stress-induced Rhamnolipid Production

The application of external stress on bacteria is a promising approach to evoke cellular responses in bioprocesses to improve production capacities. A prime example is the production of rhamnolipids, eco-friendly biosurfactants that can be used for diverse products. In this study, gene expression profiles of genes associated with the regulation of rhamnolipid synthesis as well as genes for the synthesis itself are presented to identify important points of regulation during such bio processes