The Shigella flexneri OmpA amino acid residues 188EVQ190 are essential for the interaction with the virulence factor PhoN2

Shigella flexneri is an intracellular pathogen that deploys an arsenal of virulence factors promoting host cell invasion, intracellular multiplication and intra- and inter-cellular dissemination. We have previously reported that the interaction between apyrase (PhoN2), a periplasmic ATP-diphosphohydrolase, and the C-terminal domain of the outer membrane (OM) protein OmpA is likely required for proper IcsA exposition at the old bacterial pole and thus for full virulence expression of Shigella flexneri (Scribano et al., 2014). OmpA, that is the major OM protein of Gram-negative bacteria, is a multifaceted protein that plays many different roles both in the OM structural integrity and in the virulence of several pathogens. Here, by using yeast two-hybrid technology and by constructing an in silico 3D model of OmpA from S. flexneri 5a strain M90T, we observed that the OmpA residues 188EVQ190 are likely essential for PhoN2-OmpA interaction. The 188EVQ190 amino acids are located within a flexible region of the OmpA protein that could represent a scaffold for protein-protein interaction

L-Acetylcarnitine causes analgesia in mice modeling Fabry disease by up-regulating type-2 metabotropic glutamate receptors

Fabry disease (FD) is a X-linked lysosomal storage disorder caused by deficient function of the alpha-galactosidase A (α-GalA) enzyme. α-GalA deficiency leads to multisystemic clinical manifestations caused by the preferential accumulation of globotriaosylceramide (Gb3). A hallmark symptom of FD patients is neuropathic pain that appears in the early stage of the disease as a result of peripheral small fiber damage. Previous studies have shown that Acetyl-L-carnitine (ALC) has neuroprotective, neurotrophic, and analgesic activity in animal models of neuropathic pain. To study the action of ALC on neuropathic pain associated with FD, we treated α-GalA gene null mice (α-GalA(-/0)) with ALC for 30 days. In α-Gal KO mice ALC treatment induced acute and long-lasting analgesia, which persisted 1 month after drug withdrawal. This effect was antagonized by single administration of LY341495, an orthosteric antagonist of mGlu2/3 metabotropic glutamate receptors. We also found an up-regulation of mGlu2 receptors in cultured DRG neurons isolated from 30-day ALC treated α-GalA KO mice. However, the up-regulation of mGlu2 receptors was no longer present in DRG neurons isolated 30 days after the end of treatment. Taken together, these findings suggest that ALC induces analgesia in an animal model of FD by up-regulating mGlu2 receptors, and that analgesia is maintained by additional mechanisms after ALC withdrawal. ALC might represent a valuable pharmacological strategy to reduce pain in FD patients

Characterization of the ear canal bacterial flora present in hearing Aids (HA) wearing subjects

The use of hearing aids (HA) is considered a predisposing factor for ear microbial infections. We undertook this study to compare the presence and nature of the microbial flora inhabiting of ears of HA and non-HA (nHA) users. Swab samples of the ears of HA and nHA users were collected from the Institute of Otolaryngology, “Cattolica del Sacro Cuore” University “Agostino Gemelli”, Rome, Italy. Swab samples were taken from the ear canal of 57 HA and 33 nHA users. The components of the microbial flora present on each swab sample were identified and characterized at the level of species. A total of 41 different bacterial species were identified. A statistically significant prevalence of polymicrobial communities was found in ears presenting signs of inflammation (2.5 ± 1.7 vs 2.1 ± 1.3; P = 0.02) and in HA users (2.3 ± 1.2 vs 1.7 ± 1.0; P = 0.002). Few putative pathogens were detected. Candida albicans spp. was not isolated in our study. A small number of swab samples presented no microbial growth. Bacterial species isolated from HA users with and without inflammation were assayed for the ability to form a biofilm. Among gram-positive and gram-negative bacteria, S. aureus, CoNS, P. aeruginosa, and K. pneumoniae were found to be strong biofilm producers. S. aureus and P. aeruginosa, isolated only from the ears of HA and nHA users presenting signs of inflammation, were further analyzed for their antibiotic-resistance profile and characterized by the Multilocus Sequence Typing (MLST) assay. The highest rates of antibacterial resistance were in S. aureus to a penicillin (75.5%) and in P. aeruginosa, to amoxicillin-clavulanic acid, cefotaxime, ertapenem, tigecycline and trimethoprim-sulfamethoxazole (100%). Moreover, three S. aureus strains (37.5%) were methicillin-resistant (MRSA). Of the eight S. aureus isolates, we identified six sequence types (ST) indicating that 75% are likely independent clones. For what it concerned P. aeruginosa, six different STs were assigned. Interestingly, two out of the six strains presented newly identified ST values. This study sheds new light on the combined effect of the presence of HA devices and signs of external ear inflammation on the composition of the ear bacterial flora. Our results reinforce the need to practice careful hygiene of HA devices to prevent serious ear canal infections

Systematic interaction network filtering identifies CRMP1 as a novel suppressor of huntingtin misfolding and neurotoxicity

Assemblies of huntingtin (HTT) fragments with expanded polyglutamine (polyQ) tracts are a pathological hallmark of Huntington's disease (HD). The molecular mechanisms by which these structures are formed and cause neuronal dysfunction and toxicity are poorly understood. Here, we utilized available gene expression data sets of selected brain regions of HD patients and controls for systematic interaction network filtering in order to predict disease-relevant, brain region-specific HTT interaction partners. Starting from a large protein-protein interaction (PPI) data set, a step-by-step computational filtering strategy facilitated the generation of a focused PPI network that directly or indirectly connects 13 proteins potentially dysregulated in HD with the disease protein HTT. This network enabled the discovery of the neuron-specific protein CRMP1 that targets aggregation-prone, N-terminal HTT fragments and suppresses their spontaneous self-assembly into proteotoxic structures in various models of HD. Experimental validation indicates that our network filtering procedure provides a simple but powerful strategy to identify disease-relevant proteins that influence misfolding and aggregation of polyQ disease proteins.DFG [SFB740, 740/2-11, SFB618, 618/3-09, SFB/TRR43 A7]; BMBF(NGFN-Plus) [01GS08169-73, 01GS08150, 01GS08108]; HDSA Coalition for the Cure; EU (EuroSpin) [Health-F2-2009-241498, HEALTH-F2-2009-242167]; Helmholtz Association (MSBN, HelMA) [HA-215]; FCT [IF/00881/2013]info:eu-repo/semantics/publishedVersio

Vigilância de leishmaniose visceral americana em cães de área não endêmica, São Paulo

A serological survey among domestic and stray dogs of the municipality of São José do Rio Preto, Brazil, was conducted to identify infected animals and detect the chances of transmitting the American visceral leishmaniasis . From November 1998 to June 2000, 2,104 sera samples were tested by indirect immunofluorescence reaction, using as antigen promastigotes of Leishmania (L.) chagasi. There were 2,092 no reactive samples and 12 reactive ones. Of the dogs with reactive serum it was possible to prepare lesion smears in only 3. The slide was stained by Giemsa method and only in one of them it was found amastigotes forms characteristic of Leishmania sp. This finding suggests the need of canine serological and entomological surveillance in São José do Rio Preto for an early detection of any local epidemiological changes.Realizou-se inquérito sorológico em cães domiciliados e errantes do Município de São José do Rio Preto, SP, para identificar animais infectados e detectar a possibilidade de transmissão da leishmaniose visceral americana. De novembro de 1998 a junho de 2000, 2.104 amostras de soros foram testadas por meio da reação de imunofluorescência indireta, empregando-se como antígeno formas promastigotas de Leishmania (L.) chagasi. Observaram-se 2.092 amostras não reagentes e 12 reagentes. Dos cães com sorologia positiva foi possível realizar raspados de lesão em três animais. O material fixado em lâminas foi corado por Giemsa e, em apenas um, foram encontradas formas amastigotas características de Leishmania sp. Este resultado indica a necessidade de manutenção da vigilância sorológica canina e entomológica no município de São José do Rio Preto, a fim de detectar, precocemente, qualquer alteração na epidemiologia local

Identificação sorológica de Rickettsia spp do grupo da febre maculosa em capivaras na região de Campinas, SP, Brasil

Diseases transmitted by ticks have been an important health problem all over the world. Brazilian Spotted Fever (BSF) stands for a serious epidemiological concern due to the high mortality rates pointed out. Capybaras are commonly incriminated as possible reservoirs in the BSF transmission cycle. In the last decades the numbers of these animals raised sharply and they have invaded human areas. They intensify the contact between ticks and humans beings. This study aim is to contribute to the possible role performed for this rodent in the BSF epidemiology in some areas located in Campinas region, São Paulo. Cabybaras infected by rickettsiae of BSF group were studied through the analysis of the frequencies of BSF-group rickettisae antibodies titer = 64 by indirect immunofluorescence test (IFA), and data from human cases epidemiological surveillance. The serum frequency positiveness varied greatly according to areas where animals were captured. However it was found serum positiviness only in the areas where human cases of BSF were reported. These findings suggest the capybara may be seen as sentinel animal. Due to presence of serological cross reactivity between microorganisms belonging to SF group, the results must be interpreted carefully and additional methods to distinguish pathogenic rickettsiae are required in our country.Doenças transmitidas por carrapatos vêm sendo um importante problema de saúde pública no mundo. A Febre Maculosa Brasileira (FMB) representa um sério risco epidemiológico devido às altas taxas de letalidade apresentadas. As capivaras são freqüentemente incriminadas como possíveis reservatórios no ciclo de transmissão da FMB. Nas últimas décadas o número desses animais cresceu intensamente e eles invadiram os espaços humanos. As capivaras intensificam o contato entre carrapatos e seres humanos na medida em que se apresentam muito infestadas por estes parasitos. O objetivo deste estudo é contribuir para o conhecimento do possível papel desempenhado por este roedor na epidemiologia da FMB em algumas áreas da região de Campinas, SP. Foi estudada a infecção das capivaras por rickettsias do grupo da FMB, por meio da análise das freqüências de anticorpos contra este grupo, nestes animais, e dados da vigilância epidemiológica de casos humanos. A freqüência desses anticorpos variou amplamente entre as localidades, entretanto, só foram encontrados soros com anticorpos com titulagem =64 naquelas onde havia notificação de casos humanos. Estes achados sugerem que a capivara poderá ser um animal sentinela. No entanto, devido à ocorrência de reação cruzada entre os microorganismos do grupo de FM estes resultados devem ser interpretados com cautela e são necessários métodos capazes de distinguir rickettsias patogênicas

Identificação sorológica de Rickettsia spp do grupo da febre maculosa em capivaras na região de Campinas, SP, Brasil

Diseases transmitted by ticks have been an important health problem all over the world. Brazilian Spotted Fever (BSF) stands for a serious epidemiological concern due to the high mortality rates pointed out. Capybaras are commonly incriminated as possible reservoirs in the BSF transmission cycle. In the last decades the numbers of these animals raised sharply and they have invaded human areas. They intensify the contact between ticks and humans beings. This study aim is to contribute to the possible role performed for this rodent in the BSF epidemiology in some areas located in Campinas region, São Paulo. Cabybaras infected by rickettsiae of BSF group were studied through the analysis of the frequencies of BSF-group rickettisae antibodies titer = 64 by indirect immunofluorescence test (IFA), and data from human cases epidemiological surveillance. The serum frequency positiveness varied greatly according to areas where animals were captured. However it was found serum positiviness only in the areas where human cases of BSF were reported. These findings suggest the capybara may be seen as sentinel animal. Due to presence of serological cross reactivity between microorganisms belonging to SF group, the results must be interpreted carefully and additional methods to distinguish pathogenic rickettsiae are required in our country38616941699Doenças transmitidas por carrapatos vêm sendo um importante problema de saúde pública no mundo. A Febre Maculosa Brasileira (FMB) representa um sério risco epidemiológico devido às altas taxas de letalidade apresentadas. As capivaras são freqüentemente incriminadas como possíveis reservatórios no ciclo de transmissão da FMB. Nas últimas décadas o número desses animais cresceu intensamente e eles invadiram os espaços humanos. As capivaras intensificam o contato entre carrapatos e seres humanos na medida em que se apresentam muito infestadas por estes parasitos. O objetivo deste estudo é contribuir para o conhecimento do possível papel desempenhado por este roedor na epidemiologia da FMB em algumas áreas da região de Campinas, SP. Foi estudada a infecção das capivaras por rickettsias do grupo da FMB, por meio da análise das freqüências de anticorpos contra este grupo, nestes animais, e dados da vigilância epidemiológica de casos humanos. A freqüência desses anticorpos variou amplamente entre as localidades, entretanto, só foram encontrados soros com anticorpos com titulagem =64 naquelas onde havia notificação de casos humanos. Estes achados sugerem que a capivara poderá ser um animal sentinela. No entanto, devido à ocorrência de reação cruzada entre os microorganismos do grupo de FM estes resultados devem ser interpretados com cautela e são necessários métodos capazes de distinguir rickettsias patogênica

Exposure of small mammals to ticks and rickettsiae in Atlantic Forest patches in the metropolitan area of Recife, North-eastern Brazil

Between December 2007 and March 2009, small mammals were captured in 6 Atlantic Forest patches in Brazil. We assessed tick-host associations and whether they differ among forest strata, sites, seasons, and host age classes or between sexes. Moreover, we assessed the exposure of animals to Rickettsia spp. In total, 432 animals were captured and 808 ticks were found on 32-9% of them. Significant differences were found among host species, collection sites, and forest strata; microhabitat preference was a strong risk factor for tick infestation. The highest tick density rates were recorded in forest fragments settled in rural areas; 91.3% of the ticks were collected from animals trapped in these forest fragments. A high prevalence (68.8%) of antibodies to Rickettsia spp. was detected among animals. This study suggests that disturbed Atlantic Forest fragments provide an environment for ticks and small mammals, which are highly exposed to rickettsiae. It also indicates that forest patches settled in rural areas are usually associated with higher small mammal diversity as well as with higher tick density rates.Conselho Nacional de Desenvolvimento Cientifico e Tenologioco (CNPq) [487.229/2007-0]Laboratoire Population Environnement Developpement, Universite de Provence (IRD) [UMR-151

Tumor Cell Phenotype Is Sustained by Selective MAPK Oxidation in Mitochondria

Mitochondria are major cellular sources of hydrogen peroxide (H2O2), the production of which is modulated by oxygen availability and the mitochondrial energy state. An increase of steady-state cell H2O2 concentration is able to control the transition from proliferating to quiescent phenotypes and to signal the end of proliferation; in tumor cells thereby, low H2O2 due to defective mitochondrial metabolism can contribute to sustain proliferation. Mitogen-activated protein kinases (MAPKs) orchestrate signal transduction and recent data indicate that are present in mitochondria and regulated by the redox state. On these bases, we investigated the mechanistic connection of tumor mitochondrial dysfunction, H2O2 yield, and activation of MAPKs in LP07 murine tumor cells with confocal microscopy, in vivo imaging and directed mutagenesis. Two redox conditions were examined: low 1 µM H2O2 increased cell proliferation in ERK1/2-dependent manner whereas high 50 µM H2O2 arrested cell cycle by p38 and JNK1/2 activation. Regarding the experimental conditions as a three-compartment model (mitochondria, cytosol, and nuclei), the different responses depended on MAPKs preferential traffic to mitochondria, where a selective activation of either ERK1/2 or p38-JNK1/2 by co-localized upstream kinases (MAPKKs) facilitated their further passage to nuclei. As assessed by mass spectra, MAPKs activation and efficient binding to cognate MAPKKs resulted from oxidation of conserved ERK1/2 or p38-JNK1/2 cysteine domains to sulfinic and sulfonic acids at a definite H2O2 level. Like this, high H2O2 or directed mutation of redox-sensitive ERK2 Cys214 impeded binding to MEK1/2, caused ERK2 retention in mitochondria and restricted shuttle to nuclei. It is surmised that selective cysteine oxidations adjust the electrostatic forces that participate in a particular MAPK-MAPKK interaction. Considering that tumor mitochondria are dysfunctional, their inability to increase H2O2 yield should disrupt synchronized MAPK oxidations and the regulation of cell cycle leading cells to remain in a proliferating phenotype