(p)ppGpp and CodY promote Enterococcus faecalis virulence in a murine model of catheter-associated urinary tract infection

ABSTRACT In Firmicutes, the nutrient-sensing regulators (p)ppGpp, the effector molecule of the stringent response, and CodY work in tandem to maintain bacterial fitness during infection. Here, we tested (p)ppGpp and codY mutant strains of Enterococcus faecalis in a catheter-associated urinary tract infection (CAUTI) mouse model and used global transcriptional analysis to investigate the relationship of (p)ppGpp and CodY. The absence of (p)ppGpp or single inactivation of codY led to lower bacterial loads in catheterized bladders and diminished biofilm formation on fibrinogen-coated surfaces under in vitro and in vivo conditions. Single inactivation of the bifunctional (p)ppGpp synthetase/hydrolase rel did not affect virulence, supporting previous evidence that the association of (p)ppGpp with enterococcal virulence is not dependent on the activation of the stringent response. Inactivation of codY in the (p)ppGpp0 strain restored E. faecalis virulence in the CAUTI model as well as the ability to form biofilms in vitro. Transcriptome analysis revealed that inactivation of codY restores, for the most part, the dysregulated metabolism of (p)ppGpp0 cells. While a clear linkage between (p)ppGpp and CodY with expression of virulence factors could not be established, targeted transcriptional analysis indicates that a possible association between (p)ppGpp and c-di-AMP signaling pathways in response to the conditions found in the bladder may play a role in enterococcal CAUTI. Collectively, data from this study identify the (p)ppGpp-CodY network as an important contributor to enterococcal virulence in catheterized mouse bladder and support that basal (p)ppGpp pools and CodY promote virulence through maintenance of a balanced metabolism under adverse conditions. IMPORTANCE Catheter-associated urinary tract infections (CAUTIs) are one of the most frequent types of infection found in the hospital setting that can develop into serious and potentially fatal bloodstream infections. One of the infectious agents that frequently causes complicated CAUTI is the bacterium Enterococcus faecalis, a leading cause of hospital-acquired infections that are often difficult to treat due to the exceptional multidrug resistance of some isolates. Understanding the mechanisms by which E. faecalis causes CAUTI will aid in the discovery of new druggable targets to treat these infections. In this study, we report the importance of two nutrient-sensing bacterial regulators, named (p)ppGpp and CodY, for the ability of E. faecalis to infect the catheterized bladder of mice

Evaluación de calidad de agua en un sistema ribereño utilizado para riego agrícola de subsistencia

En la evaluación del impacto de la contaminación en el ambiente, existen diversas herramientas y técnicas que se aplican para conocer la calidad ambiental de los recursos naturales. El objetivo de este trabajo fue evaluar la calidad del agua en un sistema ribereño en San Luis Potosí, México asociado al impacto del uso agrícola, urbano e industrial. Fueron establecidos cinco puntos de muestreo asociado a diversos usos y descargas residuales en donde se evaluaron 28 muestras durante cuatro días de muestro. Estas fueron distribuidas a los 20, 40, 60, 80, 100 y 120 minutos del trayecto determinando con un medidor multiparámetro los sólidos disueltos totales (SDT), temperatura (T), conductividad eléctrica (CE), pH y oxígeno disuelto (OD). El resultado más destacado de las 28 muestras diarias y del total de 112 que los promedios oxígeno disuelto indican condición hipoxia que indica la desaparición de organismos y especies sensibles, concluyendo que el área ribereña requiere un constante monitoreo y diversificación de parámetros para evaluar su condición para actividades agrícolas.In the assessment of the impact of pollution on the environment, there are various tools and techniques that are applied to know the environmental quality of natural resources. The objective of this work was to evaluate water quality in a river system in San Luis Potosí, Mexico associated with the impact of agricultural, urban and industrial use. Five sampling points associated to various uses and residual discharges were established where 28 samples were evaluated during four days of sampling. The total dissolved solids (SDT), temperature (T), electrical conductivity (CE), pH and dissolved oxygen (OD) were distributed at 20, 40, 60, 80, 100 and 120 minutes of the path. The most outstanding result of the 28 daily samples and the total of 112 that dissolved oxygen averages indicate hypoxia condition indicating the disappearance of sensitive organisms and species, concluding that the riparian area requires constant monitoring and diversification of parameters to evaluate agricultural activities.Fil: Alcalá Jáuregui, J. A. Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Acosta Doporto Geiler, A. Instituto Tecnológico Superior de los Ríos de Balancan (México)Fil: Rodríguez Ortiz, J.C. Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Hernández Montoya, A. Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Martínez Carretero, Eduardo. Consejo Nacional de Investigaciones Científicas y TécnicasFil: Filippini, Maria Flavia. Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Díaz Flores, P. E. Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Lara Mireles, J. L. Universidad Autónoma de San Luis Potosí. Facultad de Agronomí

Pilin and Sortase Residues Critical for Endocarditis- and Biofilm-Associated Pilus Biogenesis in Enterococcus faecalis

Enterococci commonly cause hospital-acquired infections, such as infective endocarditis and catheter-associated urinary tract infections. In animal models of these infections, a long hairlike extracellular protein fiber known as the endocarditis- and biofilm-associated (Ebp) pilus is an important virulence factor for Enterococcus faecalis. For Ebp and other sortase-assembled pili, the pilus-associated sortases are essential for fiber formation as they create covalent isopeptide bonds between the sortase recognition motif and the pilin-like motif of the pilus subunits. However, the molecular requirements governing the incorporation of the three pilus subunits (EbpA, EbpB, and EbpC) have not been investigated in E. faecalis. Here, we show that a Lys residue within the pilin-like motif of the EbpC subunit was necessary for EbpC polymerization. However, incorporation of EbpA into the pilus fiber only required its sortase recognition motif (LPXTG), while incorporation of EbpB only required its pilin-like motif. Only the sortase recognition motif would be required for incorporation of the pilus tip subunit, while incorporation of the base subunit would only require the pilin recognition motif. Thus, these data support a model with EbpA at the tip and EbpB at the base of an EbpC polymer. In addition, the housekeeping sortase, SrtA, was found to process EbpB and its predicted catalytic Cys residue was required for efficient cell wall anchoring of mature Ebp pili. Thus, we have defined molecular interactions involved in fiber polymerization, minor subunit organization, and pilus subcellular compartmentalization in the E. faecalis Ebp pilus system. These studies advance our understanding of unique molecular mechanisms of sortase-assembled pilus biogenesis

Oxidative Stress and Parkinson’s Disease: Effects on Environmental Toxicology

Epidemiological studies have found an increased risk of Parkinson’s disease (PD) with environmental factors such as exposure to substances derived from industrial processes, use of agrochemicals, or living in a rural environment. The hypothesis that certain environmental toxins could be the source of the EP is supported by the discovery that chemicals such as herbicides paraquat, diquat, and the fungicide maneb are selectively toxic in nigrostriatal dopaminergic neurons. Also, one of the insecticides produced by plants, such as rotenone, and by-product of the synthesis of synthetic heroin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) can be reproduced in animal models where neurochemicals, histopathological, and clinical characteristic of PD can be found. Interestingly, there are similarities in the chemical structure of paraquat and MPTP. Recent evidence exhibited that inflammation and oxidative stress play an essential role in the development of PD. So, in our laboratory we found that in an animal model melatonin decreases the products of lipid oxidation, nitric oxide metabolites, and the activity of cyclooxygenase 2, which are induced by an intraperitoneal injection of MPTP. This suggests that the neuroprotective effects of melatonin are partially attributed to its antioxidant scavenging and anti-inflammatory action

Physiology and Pathology of Neuroimmunology: Role of Inflammation in Parkinson’s Disease

Parkinson’s disease (PD) is a neurodegenerative disease that affects 1% of the population aged 65 and over and is the second most common neurodegenerative disease next to Alzheimer’s disease. Interneuronal proteinaceous inclusions called Lewy bodies (LB) and a selective degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNPC) are the main features of PD pathology. The most common clinical manifestations are rigidity, tremor, bradykinesia, postural instability, sleep disorders, alterations in gait, smell, memory, and dementia. Genetic and environmental factors are involved in PD, and, recently, oxidative stress, proteasome-mediated protein degradation, and inflammation have acquired relevance as major mechanisms of neuronal dysfunction. Increased levels of reactive oxygen and nitrogen species in the brain contribute to greater vulnerability of proteins to nitro-oxidative modification and to greater degrees of aggregation. These protein aggregates contain a variety of proteins of which α-synuclein appears to be the main structural component. Interestingly, α-synuclein can be secreted by neuronal cells and may lead the initiation and the maintenance of inflammatory events through the activation of microglia, which contributes to dopaminergic neuron depletion. New evidence also suggests that PD may be the result of an autoimmune response in which the immune cells recognize the neurons as foreign elements and would act against them, causing their death

Antimicrobial activity of apple cider vinegar against Escherichia coli, Staphylococcus aureus and Candida albicans; downregulating cytokine and microbial protein expression

The global escalation in antibiotic resistance cases means alternative antimicrobials are essential. The aim of this study was to investigate the antimicrobial capacity of apple cider vinegar (ACV) against E. coli, S. aureus and C. albicans. The minimum dilution of ACV required for growth inhibition varied for each microbial species. For C. albicans, a 1/2 ACV had the strongest effect, S. aureus, a 1/25 dilution ACV was required, whereas for E-coli cultures, a 1/50 ACV dilution was required (p < 0.05). Monocyte co-culture with microbes alongside ACV resulted in dose dependent downregulation of inflammatory cytokines (TNFα, IL-6). Results are expressed as percentage decreases in cytokine secretion comparing ACV treated with non-ACV treated monocytes cultured with E-coli (TNFα, 99.2%; IL-6, 98%), S. aureus (TNFα, 90%; IL-6, 83%) and C. albicans (TNFα, 83.3%; IL-6, 90.1%) respectively. Proteomic analyses of microbes demonstrated that ACV impaired cell integrity, organelles and protein expression. ACV treatment resulted in an absence in expression of DNA starvation protein, citrate synthase, isocitrate and malate dehydrogenases in E-coli; chaperone protein DNak and ftsz in S. aureus and pyruvate kinase, 6-phosphogluconate dehydrogenase, fructose bisphosphate were among the enzymes absent in C.albican cultures. The results demonstrate ACV has multiple antimicrobial potential with clinical therapeutic implications

The Microbiome of Brazilian Mangrove Sediments as Revealed by Metagenomics

Here we embark in a deep metagenomic survey that revealed the taxonomic and potential metabolic pathways aspects of mangrove sediment microbiology. The extraction of DNA from sediment samples and the direct application of pyrosequencing resulted in approximately 215 Mb of data from four distinct mangrove areas (BrMgv01 to 04) in Brazil. The taxonomic approaches applied revealed the dominance of Deltaproteobacteria and Gammaproteobacteria in the samples. Paired statistical analysis showed higher proportions of specific taxonomic groups in each dataset. The metabolic reconstruction indicated the possible occurrence of processes modulated by the prevailing conditions found in mangrove sediments. In terms of carbon cycling, the sequences indicated the prevalence of genes involved in the metabolism of methane, formaldehyde, and carbon dioxide. With respect to the nitrogen cycle, evidence for sequences associated with dissimilatory reduction of nitrate, nitrogen immobilization, and denitrification was detected. Sequences related to the production of adenylsulfate, sulfite, and H2S were relevant to the sulphur cycle. These data indicate that the microbial core involved in methane, nitrogen, and sulphur metabolism consists mainly of Burkholderiaceae, Planctomycetaceae, Rhodobacteraceae, and Desulfobacteraceae. Comparison of our data to datasets from soil and sea samples resulted in the allotment of the mangrove sediments between those samples. The results of this study add valuable data about the composition of microbial communities in mangroves and also shed light on possible transformations promoted by microbial organisms in mangrove sediments