1,721,101 research outputs found
Molecular and sub-cellular topology of the enzyme L-ornithine N-oxygenase (PvdA) in Pseudomonas aeruginosa
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Gut microbiota-derived outer membrane vesicles: Under-recognized major players in health and disease?
No full textThe role of gut microbiota both in human health and in disease is the subject of intense investigation. The interactions between gut microbiota and the host involve a complex network of metabolic pathways and of biologically active molecules secreted by intestinal bacteria, some of which are packed into nanoparticles known as outer membrane vesicles (OMVs). OMVs can enter the systemic circulation and be delivered to different organs including the brain, eliciting a variety of immunological and metabolic responses. The resulting acute and chronic effects are largely unknown. However, recent studies suggest that OMVs could play a critical role in immune homeostasis and in acute inflammatory reactions. Moreover, the "leaky gut" hypothesis has recently emphasized the role of the brain-gut axis in the pathogenesis of major depressive disorders, pointing to the importance of bacteria and of bacterial products delivered into the circulation in eliciting the low-grade inflammatory response associated with this syndrome. Interestingly, experimental evidence suggests that OMVs can also affect the permeability of the blood-brain barrier. This review also highlights the importance of investigating possible influences of OMVs on the development of the immune system
Pseudobactin biogenesis in the plant growth-promoting rhizobacterium Pseudomonas strain B10: Identification and functional analysis of the L-Ornithine N-5-oxygenase (psbA) gene
No full textPseudobactin(B10), the fluorescent siderophore produced by the rhizobacterium Pseudomonas strain B10, contains the hydroxamate ligand D-N-5-hydroxyornithine (D-N-5-OH-Orn). We cloned the L-Orn N-5-oxygenase (psbA) gene from a genomic library of Pseudomonas strain B10 and demonstrated that PsbA is involved in the conversion of L-Orn to its N-5-OH derivative. PsbA shows significant similarity to microbial omega-amino acid hydroxylases containing flavin adenine dinucleotide and NADP cofactor-binding sites and the FATGY signature of the putative substrate recognition pocket. The psbA gene is monocistronic, and its transcription is negatively controlled by iron. A site-specific psbA mutant of Pseudomonas strain B10 was biochemically complemented with the precursor L-N-5-OH-Orn, suggesting that L-Orn is hydroxylated before conversion to the D isomer. The L-Orn N-5-hydroxylase-defective mutants of Pseudomonas strain B10 and Pseudomonas aeruginosa PAO1 were much less effective than the parental strains in suppressing the growth of the phytopathogen Erwinia carotovora in iron-poor medium. The extent of in vitro inhibition of E. carotovora was strictly iron dependent and directly correlated with the amount of released siderophores. These data strengthen the role of fluorescent siderophores in biocontrol of deleterious rhizomicroorganisms
Gut Microbiota Profiling: Metabolomics Based Approach to Unravel Compounds Affecting Human Health
No full textThe gut microbiota is composed of a huge number of different bacteria, that produce a large amount of compounds playing a key role in microbe selection and in the construction of a metabolic signaling network. The microbial activities are affected by environmental stimuli leading to the generation of a wide number of compounds, that influence the host metabolome and human health. Indeed, metabolite profiles related to the gut microbiota can offer deep insights on the impact of lifestyle and dietary factors on chronic and acute diseases. Metagenomics, metaproteomics and metabolomics are some of the meta-omics approaches to study the modulation of the gut microbiota. Metabolomic research applied to biofluids allows to: define the metabolic profile; identify and quantify classes and compounds of interest; characterize small molecules produced by intestinal microbes; and define the biochemical pathways of metabolites. Mass spectrometry and nuclear magnetic resonance spectroscopy are the principal technologies applied to metabolomics in terms of coverage, sensitivity and quantification. Moreover, the use of biostatistics and mathematical approaches coupled with metabolomics play a key role in the extraction of biologically meaningful information from wide datasets. Metabolomic studies in gut microbiota-related research have increased, focusing on the generation of novel biomarkers, which could lead to the development of mechanistic hypotheses potentially applicable to the development of nutritional and personalized therapies
Effects of sub-lethal high-pressure homogenization treatment on the outermost cellular structures and the volatile-molecule profiles of two strains of probiotic lactobacilli
Full text linkApplying sub-lethal levels of high-pressure homogenization (HPH) to lactic acid bacteria has been proposed as a method of enhancing some of their functional properties. Because the principal targets of HPH are the cell-surface structures, the aim of this study was to examine the effect of sub-lethal HPH treatment on the outermost cellular structures and the proteomic profiles of two known probiotic bacterial strains. Moreover, the effect of HPH treatment on the metabolism of probiotic cells within a dairy product during its refrigerated storage was investigated using SPME-GC-MS. Transmission electron microscopy was used to examine the microstructural changes in the outermost cellular structures due to HPH treatment. These alterations may be involved in the changes in some of the technological and functional properties of the strains that were observed after pressure treatment. Moreover, the proteomic profiles of the probiotic strains treated with HPH and incubated at 37°C for various periods showed different peptide patterns compared with those of the untreated cells. In addition, there were differences in the peaks that were observed in the low-mass spectral region (2000-3000 Da) of the spectral profiles of the control and treated samples. Due to pressure treatment, the volatile-molecule profiles of buttermilk inoculated with treated or control cells and stored at 4°C for 30 days exhibited overall changes in the aroma profile and in the production of molecules that improved its sensory profile, although the two different species imparted specific fingerprints to the product. The results of this study will contribute to understanding the changes that occur in the outermost cellular structures and the metabolism of LAB in response to HPH treatment. The findings of this investigation may contribute to elucidating the relationships between these changes and the alterations of the technological and functional properties of LAB induced by pressure treatment.Fil: Tabanelli, Giulia. Universidad de Bologna; ItaliaFil: Vernocchi, Pamela. Irccs Ospedale Pediatrico Bambino Gesu; . Universidad de Bologna; ItaliaFil: Patrignani, Francesca. Università Degli Studi Di Bologna - Sede Di Cesena;Fil: Del Chierico, Federica. Irccs Ospedale Pediatrico Bambino Gesu;Fil: Putignani, Lorenza. Irccs Ospedale Pediatrico Bambino Gesu;Fil: Vinderola, Celso Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Reinheimer, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Gardini, Fausto. Universidad de Bologna; Italia. Università Degli Studi Di Bologna - Sede Di Cesena;Fil: Lanciotti, Rosalba. Universidad de Bologna; Italia. Università Degli Studi Di Bologna - Sede Di Cesena
Mediterranean diet and health: Food effects on gut microbiota and disease control
No full textThe Mediterranean diet (MD) is considered one of the healthiest dietary models. Many of the characteristic components of the MD have functional features with positive effects on health and wellness. The MD adherence, calculated through various computational scores, can lead to a reduction of the incidence of major diseases (e.g., cancers, metabolic and cardiovascular syndromes, neurodegenerative diseases, type 2 diabetes and allergy). Furthermore, eating habits are the main significant determinants of the microbial multiplicity of the gut, and dietary components influence both microbial populations and their metabolic activities from the early stages of life. For this purpose, we present a study proposal relying on the generation of individual gut microbiota maps from MD-aware children/adolescents. The maps, based on meta-omics approaches, may be considered as new tools, acting as a systems biology-based proof of evidence to evaluate MD effects on gut microbiota homeostasis. Data integration of food metabotypes and gut microbiota "enterotypes" may allow one to interpret MD adherence and its effects on health in a new way, employable for the design of targeted diets and nutraceutical interventions in childcare and clinical management of food-related diseases, whose onset has been significantly shifted early in life. © 2014 by the authors; licensee MDPI, Basel, Switzerland
What's in a child's ear? A case of otomyiasis by Sarcophaga argyrostoma (Diptera, Sarcophagidae)
No full text: A clinical report of otomyiasis in a 1-year-old girl is reported. A III instar larva of Sarcophaga sp. was microscopically identified and Sarcophaga (Liopygia) argyrostoma (Diptera, Sarcophagidae) was suspected. A molecular method targeting a fragment of the cox1 gene was used to confirm the identity of the specimen. Although myiases are not frequent manifestations in otolaryngology, they should arouse the attention of doctors, social workers and parents dealing with disabled people, the elderly and children. This contribution also highlights the need of combining microscopy and molecular tools to achieve a correct and reliable identification of the specimen/s
Extrachromosomal Circular DNA: An Emerging Potential Biomarker for Inflammatory Bowel Diseases?
Full text link: Inflammatory bowel disease (IBD) comprising ulcerative colitis and Crohn's disease is a chronic immune-mediated disease which affects the gastrointestinal tract with a relapsing and remitting course, causing lifelong morbidity. IBD pathogenesis is determined by multiple factors including genetics, immune and microbial factors, and environmental factors. Although therapy options are expanding, remission rates are unsatisfiable, and together with the disease course, response to therapy remains unpredictable. Therefore, the identification of biomarkers that are predictive for the disease course and response to therapy is a significant challenge. Extrachromosomal circular DNA (eccDNA) fragments exist in all tissue tested so far. These fragments, ranging in length from a few hundreds of base pairs to mega base pairs, have recently gained more interest due to technological advances. Until now, eccDNA has mainly been studied in relation to cancer due to its ability to act as an amplification site for oncogenes and drug resistance genes. However, eccDNA could also play an important role in inflammation, expressed both locally in the- involved tissue and at distant sites. Here, we review the current evidence on the molecular mechanisms of eccDNA and its role in inflammation and IBD. Additionally, the potential of eccDNA as a tissue or plasma marker for disease severity and/or response to therapy is evaluated
Gut microbiota-derived outer membrane vesicles: under-recognized major players in health and disease?
No full textThe role of gut microbiota both in human health and in disease is the subject of intense investigation. The interactions between gut microbiota and the host involve a complex network of metabolic pathways and of biologically active molecules secreted by intestinal bacteria, some of which are packed into nanoparticles known as outer membrane vesicles (OMVs). OMVs can enter the systemic circulation and be delivered to different organs including the brain, eliciting a variety of immunological and metabolic responses. The resulting acute and chronic effects are largely unknown. However, recent studies suggest that OMVs could play a critical role in immune homeostasis and in acute inflammatory reactions. Moreover, the "leaky gut" hypothesis has recently emphasized the role of the brain-gut axis in the pathogenesis of major depressive disorders, pointing to the importance of bacteria and of bacterial products delivered into the circulation in eliciting the low-grade inflammatory response associated with this syndrome. Interestingly, experimental evidence suggests that OMVs can also affect the permeability of the blood-brain barrier. This review also highlights the importance of investigating possible influences of OMVs on the development of the immune system
Gut Microbiota Dysbiosis as Risk and Premorbid Factors of IBD and IBS Along the Childhood-Adulthood Transition
No full textGastrointestinal disorders, although clinically heterogeneous, share pathogenic mechanisms, including genetic susceptibility, impaired gut barrier function, altered microbiota, and environmental triggers (infections, social and behavioral factors, epigenetic control, and diet). Gut microbiota has been studied for inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) in either children or adults, while modifiable gut microbiota features, acting as risk and premorbid factors along the childhood-adulthood transition, have not been thoroughly investigated so far. Indeed, the relationship between variations of the entire host/microbiota/environmental scenario and clinical phenotypes is still not fully understood. In this respect, tracking gut dysbiosis grading may help deciphering host phenotype-genotype associations and microbiota shifts in an integrated top-down omics-based approach within large-scale pediatric and adult case-control cohorts. Large-scale gut microbiota signatures and host inflammation patterns may be integrated with dietary habits, under genetic and epigenetic constraints, providing gut dysbiosis profiles acting as risk predictors of IBD or IBS in preclinical cases. Tracking dysbiosis supports new personalized/stratified IBD and IBS prevention programmes, generating Decision Support System tools. They include (1) high risk or flare-up recurrence-omics-based dysbiosis profiles; (2) microbial and molecular biomarkers of health and disease; (3)-omics-based pipelines for laboratory medicine diagnostics; (4) health apps for self-management of score-based dietary profiles, which can be shared with clinicians for nutritional habit and lifestyle amendment; (5)-omics profiling data warehousing and public repositories for IBD and IBS profile consultation. Dysbiosis-related indexes can represent novel laboratory and clinical medicine tools preventing or postponing the disease, finally interfering with its natural history
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