Characterization of a bacteriocin produced by enterococcus gallinarum CRL 1826 Isolated from captive bullfrog: evaluation of its mode of action against Listeria monocytogenes and gram-negatives

Enterococcus gallinarum CRL 1826 isolated from an American bullfrog (Lithobates catesbeianus) skin inhibits the growth of Citrobacter freundii, Pseudomonas aeruginosa (bullfrog pathogens) and Listeria monocytogenes by a synergistic effect between organic acids and a bacteriocin-like molecule. This bacteriocin, named enterocin CRL 1826, showed a proteinaceous nature, heat stability and polar characteristics. Its production followed kinetics of primary metabolites synthesis reaching a maximum of 61,400 AU/mL. The minimum inhibitory and minimumbactericidal concentrations were 2,640 and 5,280 AU/mL, respectively, against L. monocytogenes. The addition of 120,000 AU/mL of enterocin to growing L. monocytogenes and Gram-negative (P. aeruginosa and C. freundii) bacteria showed bactericidal and bacteriostatic effects, respectively. However, enterocin derived-peptides had bactericidal effect only against Gram-negatives.Enterocin produced cell envelope damages and efflux of citosolic content on L. monocytogenes, while enterocin derived-peptides showed granulation and contraction of cytoplasm material on P. aeruginosa and increase in theperiplasmic space and empty cells appearance on C. freundii.Enterocin CRL 1826 is the first bacteriocin described for E. gallinarum from raniculture. It could be used as a biopreservative while the derived-peptides represent an alternative to control multi-drug resistant Gram-negatives.The antimicrobial spectrum and the stability of enterocin and its derived-peptides indicate that they could be applied in different biotechnological areas.Fil: Montel Mendoza, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; ArgentinaFil: Ale, Cesar Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; ArgentinaFil: Nader, Maria Elena Fatima. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Pasteris, Sergio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; Argentin

Isolation and Selection of Potentially Beneficial Autochthonous Bacteria for Piaractus mesopotamicus Aquaculture Activities

Piaractus mesopotamicus is the most produced specie in Argentinian fish culture with an annual production of 2,017 tons. Thehigh demands of specimens generated a deficit of larvae, juveniles and sexually mature adults. The high stress conditions and theincidence of diseases had intensified this deficit. Probiotics are proven to increase survival and growth rates in aquaculture. Thefirst step in the design of a putative probiotic is the selection of adequate microorganisms to boost fish health. Lactic Acid Bacteriaand Bacillus are generally accepted as probiotics in aquaculture. In this work we obtained 522 isolates from different anatomicalparts of P. mesopotamicus, with a total of 30 lactic acid bacteria (LAB) and 8 Bacillus strains submitted for the evaluation of theirbeneficial properties. Only eight of these strains were selected for further "in vivo" assays based on following criteria: production ofinhibitory metabolites and biosurfactants, screening of antagonistic activity against foodborne and pathogenic microorganisms, abilityto emulsify polar solvents and compatibility between strains. All selected microorganisms were identified by sequencing 16S RNAgene. Pure cultures of all strains herein studied are preserved in Centro de Referencia de Lactobacilos (CERELA-CONICET) andLaboratorio de Sanidad Animal of the Estación Experimental Agropecuaria Rafaela, Instituto Nacional de Tecnología Agropecuaria(INTA) culture collectionsFil: Guidoli, Marcos Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias. Instituto de Ictiología del Nordeste; ArgentinaFil: Santinón, Juan José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias. Instituto de Ictiología del Nordeste; ArgentinaFil: Pasteris, Sergio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Sánchez, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias. Instituto de Ictiología del Nordeste; ArgentinaFil: Nader, Maria Elena Fatima. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Papel do córtex parietal posterior na realização de uma tarefa sensório-motora

This study aimed to elucidate electrophysiological and cortical mechanisms involved in anticipatory actions when individuals had to catch balls in free drop; specifically through quantitative electroencephalography (qEEG) alpha absolute power changes. The sample was composed for 23 health subjects, both sexes, with ages varying between 25 and 40 years, absence of mental and physical illness, right handed and don't make use of any psychoactive or psychotropic substance at the time of the study. The experiment consisted of a task of catching balls in free drop. The three-way ANOVA analysis demonstrated an interaction between moment and position factors in left parietal posterior cortex (PPC) (p=0.001). Through the experimental task employed, this area demonstrated a differentiated activity involving expectation, planning and preparedness in the ball's drop task.O estudo tentou elucidar mecanismos eletrofisiológicos e corticais envolvidos em ações antecipatórias quando os sujeitos testados tiveram que apreender bolas em queda livre; especificamente através de mudanças na potência absoluta na banda alfa da eletrencefalografia quantitativa (EEGq). A amostra foi composta por 23 sujeitos sadios, ambos os sexos, idade entre variando entre 25 e 40 anos, sem comprometimento físico e mental, destros, e não fazer uso de nenhuma substância psicoativa ou psicotrópicos até o momento do estudo. O experimento consistiu de uma tarefa de apreensão de bolas em queda livre. A análise three-way ANOVA demonstrou uma interação entre os fatores momento e posição no córtex parietal posterior (CPP) esquerdo (p=0,001). Através da tarefa experimental empregada, esta área demonstrou uma atividade diferenciada envolvendo expectativa, planejamento e prontidão na tarefa de queda de bolas

Skin-associated lactic acid bacteria from North American bullfrogs as potential control agents of Batrachochytrium dendrobatidis

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis and has been a key driver in the catastrophic decline of amphibians globally. While many strategies have been proposed to mitigate Bd outbreaks, few have been successful. In recent years, the use of probiotic formulations that protect an amphibian host by killing or inhibiting Bd have shown promise as an effective chytridiomycosis control strategy. The North American bullfrog (Lithobates catesbeianus) is a common carrier of Bd and harbours a diverse skin microbiota that includes lactic acid bacteria (LAB), a microbial group containing species classified as safe and conferring host benefits. We investigated beneficial/probiotic properties: anti-Bd activity, and adhesion and colonisation characteristics (hydrophobicity, biofilm formation and exopolysaccharide-EPS production) in two confirmed LAB (cLAB-Enterococcus gallinarum CRL 1826, Lactococcus garvieae CRL 1828) and 60 presumptive LAB (pLAB) [together named as LABs] isolated from bullfrog skin.We challenged LABs against eight genetically diverse Bd isolates and found that 32% of the LABs inhibited at least one Bd isolate with varying rates of inhibition. Thus, we established a score of sensitivity from highest (BdGPL AVS7) to lowest (BdGPL C2A) for the studied Bd isolates. We further reveal key factors underlying host adhesion and colonisation of LABs. Specifically, 90.3% of LABs exhibited hydrophilic properties that may promote adhesion to the cutaneous mucus, with the remaining isolates (9.7%) being hydrophobic in nature with a surface polarity compatible with colonisation of acidic, basic or both substrate types. We also found that 59.7% of LABs showed EPS synthesis and 66.1% produced biofilm at different levels: 21% weak, 29% moderate, and 16.1% strong. Together all these properties enhance colonisation of the host surface (mucus or epithelial cells) and may confer protective benefits against Bd through competitive exclusion. Correspondence analysis indicated that biofilm synthesis was LABs specific with high aggregating bacteria correlating with strong biofilm producers, and EPS producers being correlated to negative biofilm producing LABs. We performed Random Amplified Polymorphic DNA (RAPD)-PCR analysis and demonstrated a higher degree of genetic diversity among rod-shaped pLAB than cocci. Based on the LAB genetic analysis and specific probiotic selection criteria that involve beneficial properties, we sequenced 16 pLAB which were identified as Pediococcus pentosaceus, Enterococcus thailandicus, Lactobacillus pentosus/L. plantarum, L. brevis, and L. curvatus. Compatibility assays performed with cLAB and the 16 species described above indicate that all tested LAB can be included in a mixed probiotic formula. Based on our analyses, we suggest that E. gallinarum CRL 1826, L. garvieae CRL 1828, and P. pentosaceus 15 and 18B represent optimal probiotic candidates for Bd control and mitigation.Fil: Niederle, María Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Bosch, Jaime. Consejo Superior de Investigaciones Científicas; España. Universidad de Oviedo; EspañaFil: Ale, Cesar Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Nader, Maria Elena Fatima. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Aristimuño Ficoseco, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Toledo, Luis Felipe. Universidade Estadual de Campinas; BrasilFil: Valenzuela-Sánchez, Andrés. Universidad Andrés Bello; Chile. Universidad Austral de Chile; ChileFil: Soto-azat, Claudio. Universidad Andrés Bello; ChileFil: Pasteris, Sergio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentin

Biophysical interactions in the Cabo Frio upwelling system, southeastern Brazil

The rising of cold water from deeper levels characterizes coastal upwelling systems. This flow makes nutrients available in the euphotic layer, which enhances phytoplankton production and growth. On the Brazilian coast, upwelling is most intense in the Cabo Frio region (RJ). The basic knowledge of this system was reviewed in accordance with concepts of biophysical interactions. The high frequency and amplitude of the prevailing winds are the main factor promoting the rise of South Atlantic Central Water, but meanders and eddies in the Brazil Current as well as local topography and coast line are also important. Upwelling events are common during spring/summer seasons. Primary biomass is exported by virtue of the water circulation and is also controlled by rapid zooplankton predation. Small pelagic fish regulate plankton growth and in their turn are preyed on by predatory fish. Sardine furnishes an important regional fish stock. Shoreline irregularities define the embayment formation of the Marine Extractive Reserve of Arraial do Cabo making it an area with evident different intensities of upwelled water that harbors high species diversity. Consequently, on a small spatial scale there are environments with tropical and subtropical features, a point to be explored as a particularity of this ecosystem

Phospholipase-D activity and inflammatory response induced by brown spider dermonecrotic toxin: Endothelial cell membrane phospholipids as targets for toxicity

Brown spider dermonecrotic toxins (phospholipases-D) are the most well-characterized biochemical constituents of Loxosceles spp. venom. Recombinant forms are capable of reproducing most cutaneous and systemic manifestations such as dermonecrotic lesions, hematological disorders, and renal failure. There is currently no direct confirmation for a relationship between dermonecrosis and inflammation induced by dermonecrotic toxins and their enzymatic activity. We modified a toxin isoform by site-directed mutagenesis to determine if phospholipase-D activity is directly related to these biological effects. the mutated toxin contains an alanine substitution for a histidine residue at position 12 (in the conserved catalytic domain of Loxosceles intermedia Recombinant Dermonecrotic Toxin - LiRecDT1). LiRecDT1H12A sphingomyelinase activity was drastically reduced, despite the fact that circular dichroism analysis demonstrated similar spectra for both toxin isoforms, confirming that the mutation did not change general secondary structures of the molecule or its stability. Antisera against whole venom and LiRecDT1 showed cross-reactivity to both recombinant toxins by ELISA and immunoblotting. Dermonecrosis was abolished by the mutation, and rabbit skin revealed a decreased inflammatory response to LiRecDT1H12A compared to LiRecDT1. Residual phospholipase activity was observed with increasing concentrations of LiRecDT1H12A by dermonecrosis and fluorometric measurement in vitro. Lipid arrays showed that the mutated toxin has an affinity for the same lipids LiRecDT1, and both toxins were detected on RAEC cell surfaces. Data from in vitro choline release and HPTLC analyses of LiRecDT1-treated purified phospholipids and RAEC membrane detergent-extracts corroborate with the morphological changes. These data suggest a phospholipase-D dependent mechanism of toxicity, which has no substrate specificity and thus utilizes a broad range of bioactive lipids. (C) 2010 Elsevier B.V. All rights reserved.Secretaria de Estado de CienciaTecnologia e Ensino Superior (SETI) do ParanaFundacao Araucaria-PRFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ Fed Parana, Dept Cell Biol, BR-81531990 Curitiba, Parana, BrazilUniversidade Federal de São Paulo, Dept Biochem, São Paulo, BrazilUniv Estadual Ponta Grossa, Dept Struct Mol Biol & Genet, Ponta Grossa, BrazilCatholic Univ Parana, Hlth & Biol Sci Inst, Curitiba, Parana, BrazilUniversidade Federal de São Paulo, Dept Biochem, São Paulo, BrazilWeb of Scienc

Amyotrophic lateral sclerosis: one or multiple causes?

The Amyotrophic lateral sclerosis (ALS) is the most common form of motor neuron disease in the adulthood, and it is characterized by rapid and progressive compromise of the upper and lower motor neurons. The majority of the cases of ALS are classified as sporadic and, until now, a specific cause for these cases still is unknown. To present the different hypotheses on the etiology of ALS. It was carried out a search in the databases: Bireme, Scielo and Pubmed, in the period of 1987 to 2011, using the following keywords: Amyotrophic lateral sclerosis, motor neuron disease, etiology, causes and epidemiology and its similar in Portuguese and Spanish. It did not have consensus as regards the etiology of ALS. Researches demonstrates evidences as regards intoxication by heavy metals, environmental and occupational causes, genetic mutations (superoxide dismutase 1), certain viral infections and the accomplishment of vigorous physical activity for the development of the disease. There is still no consensus regarding the involved factors in the etiology of ALS. In this way, new research about these etiologies are necessary, for a better approach of the patients, promoting preventive programs for the disease and improving the quality of life of the patients