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1.
Biol Res ; 55(1): 8, 2022 Feb 22.
Article in English | MEDLINE | ID: mdl-35193678

ABSTRACT

BACKGROUND: Salmonella Typhimurium is a Gram-negative pathogen that causes a systemic disease in mice resembling typhoid fever. During its infective cycle, S. Typhimurium is phagocytized by macrophages and proliferates inside a Salmonella-containing vacuole where Salmonella is exposed and survives oxidative stress induced by H2O2 through modulation of gene expression. After exposure of Salmonella to H2O2, the expression of the porin-encoding gene ompX increases, as previously shown by microarray analysis. Expression of ompX mRNA is regulated at a post-transcriptional level by MicA and CyaR sRNAs in aerobiosis. In addition, sequence analysis predicts a site for OxyS sRNA in ompX mRNA. RESULTS: In this work we sought to evaluate the transcriptional and post-transcriptional regulation of ompX under H2O2 stress. We demonstrate that ompX expression is induced at the transcriptional level in S. Typhimurium under such conditions. Unexpectedly, an increase in ompX gene transcript and promoter activity after challenges with H2O2 does not translate into increased protein levels in the wild-type strain, suggesting that ompX mRNA is also regulated at a post-transcriptional level, at least under oxidative stress. In silico gene sequence analysis predicted that sRNAs CyaR, MicA, and OxyS could regulate ompX mRNA levels. Using rifampicin to inhibit mRNA expression, we show that the sRNAs (MicA, CyaR and OxyS) and the sRNA:mRNA chaperone Hfq positively modulate ompX mRNA levels under H2O2-induced stress in Salmonella during the exponential growth phase in Lennox broth. CONCLUSIONS: Our results demonstrate that ompX mRNA is regulated in response to H2O2 by the sRNAs CyaR, MicA and OxyS is Salmonella Typhimurium.


Subject(s)
Bacterial Outer Membrane Proteins/genetics , Porins , Salmonella typhimurium , Animals , Gene Expression Regulation, Bacterial , Hydrogen Peroxide/metabolism , Hydrogen Peroxide/pharmacology , Mice , Porins/genetics , Porins/metabolism , RNA, Bacterial/genetics , RNA, Bacterial/metabolism , Salmonella typhimurium/genetics , Salmonella typhimurium/metabolism
2.
Biol. Res ; 55: 8-8, 2022. ilus
Article in English | LILACS | ID: biblio-1383912

ABSTRACT

BACKGROUND: Salmonella Typhimurium is a Gram negative pathogen that causes a systemic disease in mice resembling typhoid fever. During its infective cycle, S. Typhimurium is phagocytized by macrophages and proliferates inside a Salmonella containing vacuole where Salmonella is exposed and survives oxidative stress induced by H2O2 through modulation of gene expression. After exposure of Salmonella to H2O2, the expression of the porin encoding gene ompX increases, as previously shown by microarray analysis. Expression of ompX mRNA is regulated at a post transcriptional level by MicA and CyaR sRNAs in aerobiosis. In addition, sequence analysis predicts a site for OxyS sRNA in ompX mRNA. RESULTS: In this work we sought to evaluate the transcriptional and post transcriptional regulation of ompX under H2O2 stress. We demonstrate that ompX expression is induced at the transcriptional level in S . Typhimurium under such conditions. Unexpectedly, an increase in ompX gene transcript and promoter activity after challenges with H2O2 does not translate into increased protein levels in the wild type strain, suggesting that ompX mRNA is also regulated at a post transcriptional level, at least under oxidative stress. In silico gene sequence analysis predicted that sRNAs CyaR, MicA, and OxyS could regulate ompX mRNA levels. Using rifampicin to inhibit mRNA expression, we show that the sRNAs (MicA, CyaR and OxyS) and the sRNA:mRNA chaperone Hfq positively modulate ompX mRNA levels under H2O2 induced stress in Salmonella during the exponential growth phase in Lennox broth. CONCLUSIONS: Our results demonstrate that ompX mRNA is regulated in response to H2O2 by the sRNAs CyaR, MicA and OxyS is Salmonella Typhimurium.


Subject(s)
Animals , Mice , Salmonella typhimurium/genetics , Salmonella typhimurium/metabolism , Bacterial Outer Membrane Proteins/genetics , Porins/genetics , Porins/metabolism , RNA, Bacterial/genetics , RNA, Bacterial/metabolism , Gene Expression Regulation, Bacterial , Hydrogen Peroxide/metabolism , Hydrogen Peroxide/pharmacology
3.
Sci Rep ; 11(1): 2429, 2021 01 28.
Article in English | MEDLINE | ID: mdl-33510337

ABSTRACT

A correlated human red blood cell membrane fluctuation dependent on D-glucose concentration was found with dual time resolved membrane fluctuation spectroscopy (D-TRMFS). This new technique is a modified version of the dual optical tweezers method that has been adapted to measure the mechanical properties of red blood cells (RBCs) at distant membrane points simultaneously, enabling correlation analysis. Mechanical parameters under different D-glucose concentrations were obtained from direct membrane flickering measurements, complemented with membrane fluidity measurements using Laurdan Generalized Polarization (GP) Microscopy. Our results show an increase in the fluctuation amplitude of the lipid bilayer, and a decline in tension value, bending modulus and fluidity as D-glucose concentration increases. Metabolic mechanisms are proposed as explanations for the results.


Subject(s)
Erythrocyte Membrane/physiology , Glucose/pharmacology , Spectrum Analysis , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/pharmacology , Adult , Biomechanical Phenomena , Erythrocyte Membrane/drug effects , Humans , Laurates/pharmacology , Membrane Fluidity/drug effects , Signal Processing, Computer-Assisted
4.
Rev. chil. obstet. ginecol ; 81(5): 411-420, 2016. ilus
Article in Spanish | LILACS | ID: biblio-830152

ABSTRACT

Se presenta el caso de paciente con ascitis, masa pelviana y CA 125 elevado, sugerentes de cáncer ovárico avanzado. Se realizó laparoscopía que demostró lesiones compatibles con tuberculosis peritoneal. La biopsia laparoscópica de las lesiones demostró granulomas, por lo que no se realizó más cirugía y se inició tratamiento antituberculoso específico con buena respuesta clínica. Se revisa en la literatura tuberculosis peritoneal y su dificultad con el diagnóstico diferencial con cáncer de ovario avanzado.


It is presented the case of a patient with ascites, pelvic mass and elevated CA 125, all suggested of advanced ovarian cancer. It was made a laparoscopy that evidenced lesions of peritoneal tuberculosis. The laparoscopic biopsy of the lesions demostrated granulomas, for that there was no more surgery made and antituberculosis specific treatment was started, with good clinical response. It is revisited in the literature peritoneal tuberculosis and its difficult differential diagnoses with advanced ovarian cancer.


Subject(s)
Humans , Female , Middle Aged , Peritonitis, Tuberculous/diagnosis , Peritonitis, Tuberculous/therapy , Anti-Bacterial Agents/therapeutic use , Ascites/etiology , Diagnosis, Differential , Laparoscopy , Ovarian Neoplasms/diagnosis , Peritonitis, Tuberculous/complications
5.
Rev. chil. obstet. ginecol ; 80(5): 414-420, ago. 2015. ilus, tab
Article in Spanish | LILACS | ID: lil-764074

ABSTRACT

Cáncer epitelial de ovario es una enfermedad altamente letal. Constituye la quinta causa de muerte por cáncer en mujeres a nivel mundial. El subtipo histológico más frecuente es el carcinoma seroso de alto grado. Este es el responsable de la alta letalidad de la enfermedad. Se presenta evidencia que respalda el origen tubario de este tipo histológico desde lesiones precursoras. A partir de estos datos se ha establecido que el cáncer tradicionalmente conocido como cáncer ovárico seroso de alto grado, el cáncer de trompa de Falopio y el carcinoma peritoneal primario, corresponden a una misma entidad nosológica: cáncer seroso pélvico de alto grado. Se revisa además la evidencia disponible para establecer que la salpingectomía podría constituir una medida de prevención para este tipo de cáncer.


Epithelial ovarian cancer is a highly lethal disease. It is the 5th cause of cancer death in women worldwide. The most common histologic subtype is the high-grade serous carcinoma. This is the responsible for the high lethality of the disease. Evidence supporting the tubal origin of this histological type from precursor lesions is presented. From these data it has been established that cancer traditionally known as serous high-grade ovarian cancer, cancer of the fallopian tube and primary peritoneal carcinoma, correspond to a single disease entity: pelvic serous high-grade cancer. We also check the available evidence to establish that the salpingectomy could be a preventive measure for this type of cancer.


Subject(s)
Humans , Female , Ovarian Neoplasms/etiology , Ovarian Neoplasms/pathology , Fallopian Tubes/pathology , Carcinoma, Ovarian Epithelial/etiology , Carcinoma, Ovarian Epithelial/pathology , Ovarian Neoplasms/genetics , Ovarian Neoplasms/prevention & control , Tumor Suppressor Protein p53 , Fallopian Tubes/surgery , Salpingectomy , Neoplasm Grading , Carcinogenesis , Carcinoma, Ovarian Epithelial/genetics , Carcinoma, Ovarian Epithelial/prevention & control
6.
Clin Exp Immunol ; 182(2): 173-83, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26174440

ABSTRACT

Epstein-Barr virus (EBV) is a persistent virus with oncogenic capacity that has been implicated in the development of aggressive B cell lymphomas, primarily in immunosuppressed individuals, although it can be present in immunocompetent individuals. Changes in the function and clonal diversity of T lymphocytes might be implied by viral persistence and lymphoma development. The aim of the present study was to evaluate the frequency, phenotype, function and clonotypical distribution of EBV-specific T cells after peripheral blood stimulation with a virus lysate in newly diagnosed patients with diffuse large B cell lymphoma (DLBCL) aged more than 50 years without prior histories of clinical immunosuppression compared with healthy controls. Our results showed impaired EBV-specific immune responses among DLBCL patients that were associated primarily with decreased numbers of central and effector memory CD8(+) T lymphocytes. In contrast to healthy controls, only a minority of the patients showed CD4(+)/tumour necrosis factor (TNF)-α(+) T cells expressing T cell receptor (TCR)-Vß17 and CD8(+)/TNF-α(+) T cells with TCR-Vß5·2, Vß9 and Vß18 in response to EBV. Notably, the production of TNF-α was undetectable among TCR-Vß5·3(+), Vß11(+), Vß12(+), Vß16(+) and Vß23(+) CD8(+) T cells. In addition, we observed decreased numbers of CD4(+)/TNF-α(+) and CD8(+)/TNF-α(+), CD8(+)/interleukin (IL)-2(+) and CD8(+)/TNF-α(+)/IL-2(+) T lymphocytes in the absence of T cells capable of producing TNF-α, IL-2 and IFN-γ after EBV stimulation simultaneously. Moreover, DLBCL patients displayed higher IL-10 levels both under baseline conditions and after EBV stimulation. These findings were also observed in patients with positive EBV viral loads. Prospective studies including a large number of patients are needed to confirm these findings.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , Epstein-Barr Virus Infections/immunology , Herpesvirus 4, Human/immunology , Lymphoma, Large B-Cell, Diffuse/immunology , Aged , Aged, 80 and over , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/virology , Epstein-Barr Virus Infections/blood , Epstein-Barr Virus Infections/virology , Female , Flow Cytometry , Herpesvirus 4, Human/physiology , Host-Pathogen Interactions/immunology , Humans , Interferon-gamma/immunology , Interferon-gamma/metabolism , Interleukin-10/immunology , Interleukin-10/metabolism , Interleukin-2/immunology , Interleukin-2/metabolism , Lymphocyte Count , Lymphoma, Large B-Cell, Diffuse/blood , Lymphoma, Large B-Cell, Diffuse/virology , Male , Middle Aged , Receptors, Antigen, T-Cell, alpha-beta/immunology , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Tumor Necrosis Factor-alpha/immunology , Tumor Necrosis Factor-alpha/metabolism , Viral Load/immunology
7.
Infect Genet Evol ; 33: 131-42, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25913156

ABSTRACT

The difference in host range between Salmonella enterica serovar Typhimurium (S. Typhimurium) and S. enterica serovar Typhi (S. Typhi) can be partially attributed to pseudogenes. Pseudogenes are genomic segments homologous to functional genes that do not encode functional products due to the presence of genetic defects. S. Typhi lacks several protein effectors implicated in invasion or other important processes necessary for full virulence of S. Typhimurium. SopA and SopE2, effectors that have been lost by pseudogenization in S. Typhi, correspond to an ubiquitin ligase involved in cytokine production by infected cells, and to a guanine exchange factor necessary for invasion of epithelial cells, respectively. We hypothesized that sopA and/or sopE pseudogenization contributed to the virulence of S. Typhi. In this work, we found that S. Typhi expressing S. Typhimurium sopE2 exhibited a decreased invasion in different epithelial cell lines compared with S. Typhi WT. S. Typhimurium sopA completely abolished the hypo-invasive phenotype observed in S. Typhi expressing S. Typhimurium sopE2, suggesting that functional SopA and SopE2 participate concertedly in the invasion process. Finally, the expression of S. Typhimurium sopA and/or sopE2 in S. Typhi, determined changes in the secretion of IL-8 and IL-18 in infected epithelial cells.


Subject(s)
Bacterial Proteins/genetics , Guanine Nucleotide Exchange Factors/genetics , Salmonella typhi/genetics , Salmonella typhi/pathogenicity , Typhoid Fever/microbiology , Virulence/genetics , Bacterial Proteins/metabolism , Cytokines/metabolism , Epithelial Cells/metabolism , Epithelial Cells/microbiology , Gene Expression , Genotype , Guanine Nucleotide Exchange Factors/metabolism , Host-Pathogen Interactions , Humans , Mutation , Pseudogenes
8.
Microbiology (Reading) ; 159(Pt 10): 2049-2057, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23918818

ABSTRACT

In response to antibiotics, bacteria activate regulatory systems that control the expression of genes that participate in detoxifying these compounds, like multidrug efflux systems. We previously demonstrated that the BaeSR two-component system from Salmonella enterica serovar Typhimurium (S. Typhimurium) participates in the detection of ciprofloxacin, a bactericidal antibiotic, and in the positive regulation of mdtA, an efflux pump implicated in antibiotic resistance. In the present work, we provide further evidence for a role of the S. Typhimurium BaeSR two-component system in response to ciprofloxacin treatment and show that it regulates sodA expression. We demonstrate that, in the absence of BaeSR, the transcript levels of sodA and the activity of its gene product are lower. Using electrophoretic mobility shift assays and transcriptional fusions, we demonstrate that BaeR regulates sodA by a direct interaction with the promoter region.


Subject(s)
Anti-Bacterial Agents/metabolism , Bacterial Proteins/biosynthesis , Ciprofloxacin/metabolism , Gene Expression Regulation, Bacterial , Multidrug Resistance-Associated Proteins/metabolism , Protein Kinases/metabolism , Salmonella typhimurium/drug effects , Superoxide Dismutase/biosynthesis , Trans-Activators/metabolism , Artificial Gene Fusion , DNA, Bacterial/metabolism , Electrophoretic Mobility Shift Assay , Gene Expression Profiling , Gene Knockout Techniques , Multidrug Resistance-Associated Proteins/genetics , Promoter Regions, Genetic , Protein Binding , Protein Kinases/genetics , Trans-Activators/genetics , Transcription, Genetic
9.
Sci Rep ; 3: 2316, 2013.
Article in English | MEDLINE | ID: mdl-23897033

ABSTRACT

The secure transfer of information is an important problem in modern telecommunications. Quantum key distribution (QKD) provides a solution to this problem by using individual quantum systems to generate correlated bits between remote parties, that can be used to extract a secret key. QKD with D-dimensional quantum channels provides security advantages that grow with increasing D. However, the vast majority of QKD implementations has been restricted to two dimensions. Here we demonstrate the feasibility of using higher dimensions for real-world quantum cryptography by performing, for the first time, a fully automated QKD session based on the BB84 protocol with 16-dimensional quantum states. Information is encoded in the single-photon transverse momentum and the required states are dynamically generated with programmable spatial light modulators. Our setup paves the way for future developments in the field of experimental high-dimensional QKD.

10.
Rev. chil. nutr ; 40(1): 71-78, mar. 2013. ilus
Article in Spanish | LILACS | ID: lil-679035

ABSTRACT

El objetivo del presente estudio fue determinar las características polínicas y la composición química del polen apícola, colectado en El Cafetal, Cayaltí (Lambayeque, Perú), un área rural del bosque estacionalmente seco. El polen apícola se colectó directamente de las colmenas y se clasificó en cuatro grupos de colores: amarillo, anaranjado, crema y gris. El análisis polínico reveló la presencia de polen de las especies: Acacia macracantha Humboldt & Bonpland, Encelia canescens Lamarck, Momordica charantia L. y Prosopis pallida (Humboldt & Bonpland ex Willdenow) H.B.K. El polen de P. pallida predominó en el polen apícola gris (98,1%) y amarillo (87,7%) en tanto que el polen de E. canescens predominó en el polen apícola anaranjado (72,7%) y crema (50,0%). Se observó una gran diversidad en las características morfológicas del polen, en la forma (poliada, oblado esferoidal y prolado esferoidal), elementos esculturales (liso, espinado y reticulado) y aberturas (tricolporado y estefanocolpado). Se determinó los contenidos de humedad (8,8 - 13,8%), cenizas (2,1 - 3,2%), calcio (6,4 - 12,4%), vitamina C (208 - 504 mg), azúcares totales y reductores (35 - 49,7 y 22,4 - 26%, respectivamente), grasas (0,15 - 0,18%) y proteínas (13,7 - 17,3%), observándose significativas variaciones en función del color del polen apícola. El valor nutritivo fue mayor en el polen apícola gris alcanzando el valor 3,51; en este color de polen apícola predominó P. pallida.


The aim of this study was to determine the pollen and chemical composition offour types ofbee pollen, collected in The Cafetal, Cayaltí (Lambayeque, Perú), a rural area of Perú seasonally dry forest. Bee pollen was collected directly from the hives and classified into four groups ofcolors: yellow, orange, cream and gray. Pollen analysis revealed the presence ofpollen in species: Acacia macracantha Humboldt & Bonpland, Encelia canescens Lamarck, Momordica charantia L. and Prosopis pallida (Humboldt & Bon-pland ex Willdenow) H.B.K. The pollen of P. pallida was predominant in the gray (98,1%) and yellow (87,7%) bee pollen; while pollen of E. canecens was predominant in the orange (72,7%) and cream (50,0%) bee pollen, respectively. A great diversity in the pollen morphology (polyad, oblate spheroidal and prolate spheroidal), scultural elements (psilate, echinate and reticulate) and openings (tricolporate and stephanocolpate) was observed. The moisture (8,8 - 13,8%), ash content (2,1 - 3,2%), calcium (6,4 - 12,4%), vitamin C (208 - 504 mg), total and reducing sugars (35 - 49,7y 22,4 - 26%, respectively), fat (0,15 - 0,18%) and proteins (13,7 - 17,3%) was determined, showing significant variations depending on the color of bee pollen. The nutritive value was higher in the gray bee pollen reaching the value 3.51; in this color was predominant P. pallida pollen.


Subject(s)
Pollen/chemistry , Forests , Nutritive Value , Peru , Chemical Phenomena
11.
Opt Express ; 21(1): 102-11, 2013 Jan 14.
Article in English | MEDLINE | ID: mdl-23388900

ABSTRACT

We report the experimental implementation of a new method for generating multiple dynamical optical tweezers, where each one of them is generated with an independent linear polarization state with arbitrary orientation. This also allows an independent simultaneous polarization-rotation control. The laser beam, both for generating multiple traps and polarization control, has been modulated using a single reflective nematic liquid crystal with parallel alignment. We present experimental results of controlled displacement, orientation and rotation of birefringent particles. In addition, a simple method for estimating and canceling out the primary astigmatism present in the system is presented.


Subject(s)
Biophysics/methods , Birefringence , Holography/instrumentation , Optical Tweezers , Rotation , Algorithms , DNA/chemistry , Dimerization , Equipment Design , Holography/methods , Liquid Crystals , Optics and Photonics/methods , Particle Size , Stress, Mechanical , Ultraviolet Rays
12.
Microbiology (Reading) ; 159(Pt 4): 715-725, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23393149

ABSTRACT

OmpW is a minor porin whose biological function has not been clearly defined. Evidence obtained in our laboratory indicates that in Salmonella enterica serovar Typhimurium the expression of OmpW is activated by SoxS upon exposure to paraquat and it is required for resistance. SoxS belongs to the AraC family of transcriptional regulators, like MarA and Rob. Due to their high structural similarity, the genes under their control have been grouped in the mar/sox/rob regulon, which presents a DNA-binding consensus sequence denominated the marsox box. In this work, we evaluated the role of the transcription factors MarA, SoxS and Rob of S. enterica serovar Typhimurium in regulating ompW expression in response to menadione. We determined the transcript and protein levels of OmpW in different genetic backgrounds; in the wild-type and Δrob strains ompW was upregulated in response to menadione, while in the ΔmarA and ΔsoxS strains the induction was abolished. In a double marA soxS mutant, ompW transcript levels were lowered after exposure to menadione, and only complementation in trans with both genes restored the positive regulation. Using transcriptional fusions and electrophoretic mobility shift assays with mutant versions of the promoter region we demonstrated that two of the predicted sites were functional. Additionally, we demonstrated that MarA increases the affinity of SoxS for the ompW promoter region. In conclusion, our study shows that ompW is upregulated in response to menadione in a cooperative manner by MarA and SoxS through a direct interaction with the promoter region.


Subject(s)
Bacterial Outer Membrane Proteins/metabolism , Bacterial Proteins/metabolism , Trans-Activators/metabolism , Vitamin K 3/pharmacology , Bacterial Outer Membrane Proteins/genetics , Bacterial Proteins/genetics , Bacterial Proteins/pharmacology , Electrophoretic Mobility Shift Assay , Promoter Regions, Genetic , Salmonella typhimurium/genetics , Salmonella typhimurium/metabolism , Trans-Activators/genetics , Trans-Activators/pharmacology , Up-Regulation/drug effects
13.
Clin Microbiol Infect ; 19(4): 356-61, 2013 Apr.
Article in English | MEDLINE | ID: mdl-22414066

ABSTRACT

Previous studies on commensal Escherichia coli from healthy children in the Bolivian Chaco have shown remarkable resistance rates to the old antibiotics since the early 1990s, and the emergence of resistance to newer drugs (fluoroquinolones and expanded-spectrum cephalosporins) in the 2000s. Here we report the results of a new survey conducted in 2011 in the same setting. Rectal swabs were obtained from 482 healthy children (aged 6-72 months) from three urban areas of the Bolivian Chaco. Screening for antibiotic-resistant E. coli was performed by a direct plating method, as in the previous studies. The blaCTX-M genes were investigated by PCR/sequencing, and CTX-M-producing isolates were subjected to genotyping and detection of several plasmid-mediated quinolone resistance mechanisms. Results showed high rates of resistance to nalidixic acid (76%), ciprofloxacin (44%) and expanded-spectrum cephalosporins (12.4%), demonstrating a relentless increase of resistance to those drugs over the past two decades. CTX-M-type extended-spectrum beta-lactamases were found to be widespread (12%, 97% of extended-spectrum beta-lactamase producers). Compared with the previous studies, CTX-M-producing E. coli underwent a dramatic dissemination (120-fold increase since early 2000s) and a radical change of dominant CTX-M groups (CTX-M-1 and CTX-M-9 groups versus CTX-M-2 group). Most CTX-M producers were not susceptible to quinolones (91%), and 55% carried plasmid-mediated quinolone resistance genes (different combinations of aac(6')-Ib-cr, qnrB and qepA). This study shows the rapid and remarkable increasing trend for resistance to fluoroquinolones and expanded-spectrum cephalosporins in one of the poorest regions of Latin America, and underscores the need for urgent control strategies aimed at preserving the efficacy of those drugs in similar settings.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cephalosporins/pharmacology , Drug Resistance, Bacterial , Escherichia coli Infections/epidemiology , Escherichia coli/drug effects , Fluoroquinolones/pharmacology , Bolivia/epidemiology , Child , Child, Preschool , Escherichia coli/isolation & purification , Escherichia coli Infections/microbiology , Female , Genotype , Humans , Infant , Male , Microbial Sensitivity Tests , Plasmids/analysis , Polymerase Chain Reaction , Rectum/microbiology , Sequence Analysis, DNA
14.
Arch Microbiol ; 194(11): 933-42, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22752112

ABSTRACT

To survive, Salmonella enterica serovar Typhimurium (S. Typhimurium) must sense signals found in phagocytic cells and modulate gene expression. In the present work, we evaluated the expression and cross-regulation of the transcription factors MarA, Rob, and SoxS in response to NaOCl. We generated strains ΔsoxS and ΔmarA, which were 20 times more sensitive to NaOCl as compared to the wild-type strain; while Δrob only 5 times. Subsequently, we determined that marA and soxS transcript and protein levels were increased while those of rob decreased in a wild-type strain treated with NaOCl. To assess if changes in S. Typhimurium after exposure to NaOCl were due to a cross-regulation, as in Escherichia coli, we evaluated the expression of marA, soxS, and rob in the different genetic backgrounds. The positive regulation observed in the wild-type strain of marA and soxS was retained in the Δrob strain. As in the wild-type strain, rob was down-regulated in the ΔmarA and ΔsoxS treated with NaOCl; however, this effect was decreased. Since rob was down-regulated by both factors, we generated a ΔmarA ΔsoxS strain finding that the negative regulation was abolished, confirming our hypothesis. Electrophoretic mobility shift assays using MarA and SoxS confirmed an interaction with the promoter of rob.


Subject(s)
Gene Expression Regulation, Bacterial/drug effects , Salmonella typhimurium/drug effects , Salmonella typhimurium/genetics , Sodium Hypochlorite/pharmacology , Transcription Factors/genetics , Down-Regulation , Electrophoretic Mobility Shift Assay , Mutation , Oxidants/pharmacology , Promoter Regions, Genetic , Protein Binding , Salmonella typhimurium/metabolism , Transcription Factors/metabolism
15.
Arch Microbiol ; 194(6): 453-60, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22173828

ABSTRACT

Two-component systems are one of the most prevalent mechanisms by which bacteria sense, respond and adapt to changes in their environment. The activation of a sensor histidine kinase leads to autophosphorylation of a conserved histidine residue followed by transfer of the phosphoryl group to a cognate response regulator in an aspartate residue. The search for antibiotics that inhibit molecular targets has led to study prokaryotic two-component systems. In this study, we characterized in vitro and in vivo the BaeSR two-component system from Salmonella Typhimurium and evaluated its role in mdtA regulation in response to ciprofloxacin treatment. We demonstrated in vitro that residue histidine 250 is essential for BaeS autophosphorylation and aspartic acid 61 for BaeR transphosphorylation. By real-time PCR, we showed that mdtA activation in the presence of ciprofloxacin depends on both members of this system and that histidine 250 of BaeS and aspartic acid 61 of BaeR are needed for this. Moreover, the mdtA expression is directly regulated by binding of BaeR at the promoter region, and this interaction is enhanced when the protein is phosphorylated. In agreement, a BaeR mutant unable to phosphorylate at aspartic acid 61 presents a lower affinity with the mdtA promoter.


Subject(s)
Anti-Bacterial Agents/pharmacology , Ciprofloxacin/pharmacology , Multidrug Resistance-Associated Proteins/metabolism , Protein Kinases/metabolism , Salmonella typhimurium/genetics , Trans-Activators/metabolism , Aspartic Acid/metabolism , Cloning, Molecular , Gene Expression Regulation, Bacterial/drug effects , Histidine/metabolism , Histidine Kinase , Multidrug Resistance-Associated Proteins/genetics , Mutagenesis, Site-Directed , Phosphorylation , Promoter Regions, Genetic , Protein Binding , Protein Kinases/genetics , Salmonella typhimurium/drug effects , Salmonella typhimurium/physiology , Trans-Activators/genetics
16.
Opt Express ; 19(4): 3542-52, 2011 Feb 14.
Article in English | MEDLINE | ID: mdl-21369178

ABSTRACT

We present the experimental quantum tomography of 7- and 8-dimensional quantum systems based on projective measurements in the mutually unbiased basis (MUB-QT). One of the advantages of MUB-QT is that it requires projections from a minimal number of bases to be performed. In our scheme, the higher dimensional quantum systems are encoded using the propagation modes of single photons, and we take advantage of the capabilities of amplitude- and phase-modulation of programmable spatial light modulators to implement the MUB-QT.

17.
Microbiology (Reading) ; 157(Pt 3): 636-647, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21148209

ABSTRACT

Salmonella enterica serovar Typhi (S. Typhi) is the aetiological agent of typhoid fever in humans. This bacterium is also able to persist in its host, causing a chronic disease by colonizing the spleen, liver and gallbladder, in the last of which the pathogen forms biofilms in order to survive the bile. Several genetic components, including the yihU-yshA genes, have been suggested to be involved in the survival of Salmonella in the gallbladder. In this work we describe how the yihU-yshA gene cluster forms a transcriptional unit regulated positively by the cAMP receptor global regulator CRP (cAMP receptor protein). The results obtained show that two CRP-binding sites on the regulatory region of the yihU-yshA operon are required to promote transcriptional activation. In this work we also demonstrate that the yihU-yshA transcriptional unit is carbon catabolite-repressed in Salmonella, indicating that it forms part of the CRP regulon in enteric bacteria.


Subject(s)
Bacterial Outer Membrane Proteins/metabolism , Cyclic AMP Receptor Protein/metabolism , Gene Expression Regulation, Bacterial , Hydroxybutyrate Dehydrogenase/metabolism , Operon , Salmonella typhi/genetics , Salmonella typhi/metabolism , Bacterial Outer Membrane Proteins/genetics , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Binding Sites , Catabolite Repression , Humans , Hydroxybutyrate Dehydrogenase/chemistry , Hydroxybutyrate Dehydrogenase/genetics , Mutagenesis, Site-Directed , Salmonella typhi/growth & development , Typhoid Fever/microbiology
18.
Opt Express ; 17(13): 10688-96, 2009 Jun 22.
Article in English | MEDLINE | ID: mdl-19550465

ABSTRACT

The study of how to generate high-dimensional quantum states (qudits) is justified by the advantages that they can bring for the field of quantum information. However, to have some real practical potential for quantum communication, these states must be also of simple manipulation. Spatial qudits states, which are generated by engineering the transverse momentum of the parametric down-converted photons, have been until now considered of hard manipulation. Nevertheless, we show in this work a simple technique for modifying these states. This technique is based on the use of programmable diffractive optical devices, that can act as spatial light modulators, to define the Hilbert space of these photons instead of pre-fabricated multi-slits.

19.
Microbiology (Reading) ; 155(Pt 8): 2490-2497, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19460824

ABSTRACT

OmpW of Salmonella enterica serovar Typhimurium has been described as a minor porin involved in osmoregulation, and is also affected by environmental conditions. Biochemical and genetic evidence from our laboratory indicates that OmpW is involved in efflux of and resistance towards paraquat (PQ), and its expression has been shown to be activated in response to oxidative stress. In this study we have explored ompW expression in response to PQ. Primer extension and transcriptional fusions showed that its expression was induced in the presence of PQ. In silico analyses suggested a putative binding site for the SoxS transcriptional factor at the ompW regulatory region. Electrophoretic mobility shift assays (EMSAs) and footprinting experiments showed that SoxS binds at a region that starts close to -54 and ends at about -197 upstream of the transcription start site. Transcriptional fusions support the relevance of this region in ompW activation. The SoxS site is in the forward orientation and its location suggests that the ompW gene has a class I SoxS-dependent promoter.


Subject(s)
Bacterial Outer Membrane Proteins , Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial/drug effects , Salmonella typhimurium/metabolism , Trans-Activators/metabolism , Bacterial Outer Membrane Proteins/biosynthesis , Bacterial Outer Membrane Proteins/genetics , DNA, Bacterial/analysis , DNA, Bacterial/genetics , Electrophoresis, Polyacrylamide Gel , Electrophoretic Mobility Shift Assay , Herbicides/pharmacology , Paraquat/pharmacology , Promoter Regions, Genetic , Salmonella typhimurium/drug effects , Salmonella typhimurium/genetics , Sequence Analysis, DNA , Transcriptional Activation/drug effects
20.
Rev. chil. obstet. ginecol ; 73(5): 325-329, 2008. ilus
Article in Spanish | LILACS | ID: lil-520638

ABSTRACT

Antecedentes: La infección persistente por VPH de alto riesgo se asocia con cáncer cervicouterino, encontrándosepositividad en el 99,7% de los casos. Las verrugas anogenitales son una forma de presentación de la infección persistente. Objetivo: Investigar la eficacia y seguridad de imiquimod en crema al 5%, en el tratamiento de las verrugas anogenitales en mujeres. Método: Estudio prospectivo no randomizado, en mujeres portadoras de verrugas anogenitales asociadas a VPH. El tratamiento consiste en la autoaplicación de imiquiomod en crema al 5% tres veces a la semana por hasta un período de 16 semanas. Se define como respuesta completa al tratamiento aquella en que desaparece completamente la lesión; por respuesta parcial la disminución de al menos un 50% del volumen inicial de la lesión. Resultados: Durante un período de 8 meses fueron ingresadas y tratadas 38 pacientes La duración del tratamiento varió entre 1 y 4 meses. El número promedio de aplicaciones fue de 28,7. El 66% (25 casos) de las pacientes presentaron una respuesta completa, en tres casos no hubo respuesta, uno de ellos en una paciente inmunodeprimida, en 10 casos hubo respuestas parciales. En las pacientes con respuestas completas se necesitó un promedio de 28,7 aplicaciones hasta obtener el resultado. Conclusiones: Imiquimod es un fármaco con buena efectividad y seguridad en el tratamiento de las verrugas anogenitales asociadas a VPH, en tratamiento de tres veces por semana durante mínimo de 10 semanas.


Background: The chronic infection by high-risk HPV serotypes is strongly associated with cervical cancer, detection of HPV on tissue sample has been reported 99.7% of cases. The anal-genital warts represent the clinical manifestation of the persistent infection by this virus. Objectives: To investigate the efficacy and safety of Imiquimod cream 5% concentration, in the treatment of anal-genital warts in women. Methods: A non-randomized prospective study in women diagnosed with anal-genital warts HPV associated. The treatment consists in self-application of imiquimod cream 5%, three times a week for a period of 16 weeks or more. We define complete response to treatment in those patients where the lesion disappeared completely, and partial response to those where the lesion declined at least 50% of its initial volume. Results: Over a period of 8 months were admitted to the study and treated a total of 38 patients. Treatment duration varied between 1 and 4 months. The average number of applications was 28.7 times. 66% (25 cases) of the patients had a complete response, in three cases there was no response, one of them was an immunodepressed patients, in 10 cases there was partial response. The patients with complete response needed an average of 28.7 applications to get that result. Conclusions: Imiquimod is a drug with high effectiveness and safety in the treatment of anal-genital warts HPV associated, in a three times per week and at least 10 weeks total duration treatment.


Subject(s)
Humans , Female , Adolescent , Adult , Middle Aged , Adjuvants, Immunologic/administration & dosage , Aminoquinolines/administration & dosage , Genital Diseases, Female/drug therapy , Anus Diseases/drug therapy , Papillomavirus Infections/drug therapy , Genital Diseases, Female/virology , Anus Diseases/virology , Prospective Studies , Treatment Outcome , Warts/drug therapy
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