417 research outputs found

    Spectra of algebras of holomorphic functions of bounded type

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    AbstractWe prove that if U is a balanced Hb (U)-domain of holomorphy in Tsirelson's space then the spectrum of Hb (U) is identified with U. We derive theorems of Banach Stone type for algebras of holomorphic functions and algebras of holomorphic germs

    System analysis of metabolism in Helicobacter pylori

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    Systems biology integrates different levels of information for understanding biological systems. The availability of the genome sequence of Helicobacter pylori has allowed the construction of a genome-scale metabolic model for this organism. In order to study the behaviour of H. pylori and understand the mechanisms associated with infection using systems biology tools and controlled cultivation conditions, fermentations in a chemically defined medium were performed and several conditions were tested. The experimental data obtained were compared with simulated data generated by the existing model. The simultaneous use of both approaches allows to correct the in silico model and, on the other hand, to rationally adjust the medium components. The improvement of the genome-scale metabolic model will allow the identification of potential targets in order to design more effective drugs for the inactivation of H. pylori

    Development and characterization of pectin films with Salicornia ramosissima: biodegradation in soil and seawater

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    Pectin films were developed by incorporating a halophyte plant Salicornia ramosissima (dry powder from stem parts) to modify the film’s properties. The films’ physicomechanical properties, Fourier-transform infrared spectroscopy (FTIR), and microstructure, as well as their biodegradation capacity in soil and seawater, were evaluated. The inclusion of S. ramosissima significantly increased the thickness (0.25 ± 0.01 mm; control 0.18 ± 0.01 mm), color parameters a* (4.96 ± 0.30; control 3.29 ± 0.16) and b* (28.62 ± 0.51; control 12.74 ± 0.75), water vapor permeability (1.62 × 10−9 ± 1.09 × 10−10 (g/m·s·Pa); control 1.24 × 10−9 ± 6.58 × 10−11 (g/m·s·Pa)), water solubility (50.50 ± 5.00%; control 11.56 ± 5.56%), and elongation at break (5.89 ± 0.29%; control 3.91 ± 0.62%). On the other hand, L* (48.84 ± 1.60), tensile strength (0.13 ± 0.02 MPa), and Young’s modulus (0.01 ± 0 MPa) presented lower values compared with the control (L* 81.20 ± 1.60; 4.19 ± 0.82 MPa; 0.93 ± 0.12 MPa), while the moisture content varied between 30% and 45%, for the film with S. ramosissima and the control film, respectively. The addition of S. ramosissima led to opaque films with relatively heterogeneous microstructures. The films showed also good biodegradation capacity—after 21 days in soil (around 90%), and after 30 days in seawater (fully fragmented). These results show that pectin films with S. ramosissima may have great potential to be used in the future as an eco-friendly food packaging material.info:eu-repo/semantics/publishedVersio

    Comparison of H. pylori in silico metabolic model predictions with experimental data

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    [Excerpt] The Systems Biology approach has been replacing the reductionist view that dominated biology research in the last decades. Present biochemical knowledge and genomic databases allowed the development of metabolic models for several organisms, which, however, are still incomplete. The availability of the genome sequence of H. pylori has allowed the construction of a genome-scale metabolic model for this organism. The purposes of this work were to study the growth of H. pylori in a chemically defined medium, to compare the experimental data obtained with the simulated data supplied by the model and analyse the composition of the in silico media used. [...

    Growth assessment methods for Helicobacter pylori in liquid medium

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    Helicobacter pylori is known to be associated with chronic gastritis, peptic ulcers and gastric cancer. The lack of physiological data has hampered the uncover of mechanisms associated with H. pylori infection and consequently, many aspects related with the appearance of diseases remain unclear. It is well known that H. pylori can change cell morphology from spiral to coccoid form when exposed to adverse conditions. Some authors have reported the existence of a viable but nonculturable state of this bacterium. The development of robust methods to grow this bacterium and reliable methods for the assessment of growth are needed for a better characterization of its physiology. As such, the purpose of this work was to study H. pylori growth in a chemically defined medium, compare different methods to assess the growth and observe the changes of morphology. Cultures were grown at 37ºC under controlled conditions in Ham´s F-12 medium supplemented with fetal bovine serum. Samples were collected until 72 hours. For growth assessment, the following methods were used and compared: optical density, cultivable cell counts, total cell counts using DAPI staining, evaluation of viability with the Live/Dead viability kit and a PNA FISH probe which evaluates the content of stable rRNA. Cell counts and analysis of cell morphology were assessed using an epifluorescence microscope. Under the conditions of atmospheric oxygen 6.5%, pH 7, and shaking speed 110 rpm, H. pylori was in exponential growth from 0 to 4 hours. In comparison to total counts, PNA FISH displayed, in general, lower counts, particularly after cells have reached the stationary phase. Changes in morphology and viability were observed. After 60 hours of culture cells were mainly coccoid and nonviable

    Influence of human t-cell lymphotropic virus type 1 (HTLV-1) Infection on laboratory parameters of patients with chronic hepatitis C virus

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    Hepatitis C virus (HCV) and human T-cell lymphotropic virus type 1 (HTLV-1) share routes of transmission and some individuals have dual infection. Although some studies point to a worse prognosis of hepatitis C virus in patients co-infected with HTLV-1, the interaction between these two infections is poorly understood. This study evaluated the influence of HTLV-1 infection on laboratory parameters in chronic HCV patients. Twelve HTLV-1/HCV-coinfected patients were compared to 23 patients infected only with HCV, in regard to demographic data, risk factors for viral acquisition, HCV genotype, presence of cirrhosis, T CD4+ and CD8+ cell counts and liver function tests. There was no difference in regard to age, gender, alcohol consumption, smoking habits, HCV genotype or presence of cirrhosis between the groups. Intravenous drug use was the most common risk factor among individuals co-infected with HTLV-1. These patients showed higher TCD8+ counts (p = 0.0159) and significantly lower median values of AST and ALT (p = 0.0437 and 0.0159, respectively). In conclusion, we have shown that HCV/HTLV-1 co-infected patients differs in laboratorial parameters involving both liver and immunological patterns. The meaning of these interactions in the natural history of these infections is a matter that deserves further studies.O vírus da hepatite C (VHC) e vírus linfotrópico humano tipo 1 (HTLV-1) compartilham formas de transmissão e algumas pessoas apresentam coinfecção. Embora alguns estudos apontem para um pior prognóstico da infecção pelo VHC em pacientes coinfectados com HTLV-1, a interação entre estas infecções é mal compreendida. Este estudo avaliou a influência da infecção pelo HTLV-1 em parâmetros laboratoriais de pacientes com VHC. 12 coinfectados VHC/HTLV-1 foram comparados com 23 pacientes monoinfectados com VHC, no que diz respeito aos dados demográficos, fatores de risco para aquisição viral, genótipo do VHC, presença de cirrose, contagens de linfócitos T CD4+ e CD8+ e testes de função hepática. Não houve diferença em relação à idade, sexo, consumo de álcool, tabagismo, genótipo do VHC ou presença de cirrose entre os grupos. O uso de drogas injetáveis foi o fator de risco mais comum entre coinfectados. Esses pacientes apresentaram maiores contagens de linfócitos T CD8+ e valores medianos de AST e ALT significativamente mais baixos (p = 0,0437 e 0,0159, respectivamente). Em conclusão, demonstrou-se que os pacientes com VHC/HTLV-1 diferem quanto aos parâmetros hepáticos e imunológicos. O significado destas diferenças na história natural destas infecções é um assunto que merece estudos mais aprofundados

    Growth assessment of Helicobacter pylori in liquidmedium – effect of aggregation

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    Helicobacter pylori is a pathogenic organism associated with gastric diseases. It is described that H. pylori can change morphology when exposed to adverse conditions and H. pylori cells can aggregate in clusters when in liquid culture. Such phenomenon makes it difficult to assess growth using the conventional methods. The development of robust methods to assess growth in a more reliable way is needed. In the present work a method that allows efficient cell disaggregation was developed.Fundação para a Ciência e Tecnologia (FCT) PhD Grant (SFRH/BD/47596/2008

    Human fallopian tube: a new source of multipotent adult mesenchymal stem cells discarded in surgical procedures

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    <p>Abstract</p> <p>Background</p> <p>The possibility of using stem cells for regenerative medicine has opened a new field of investigation. The search for sources to obtain multipotent stem cells from discarded tissues or through non-invasive procedures is of great interest. It has been shown that mesenchymal stem cells (MSCs) obtained from umbilical cords, dental pulp and adipose tissue, which are all biological discards, are able to differentiate into muscle, fat, bone and cartilage cell lineages. The aim of this study was to isolate, expand, characterize and assess the differentiation potential of MSCs from human fallopian tubes (hFTs).</p> <p>Methods</p> <p>Lineages of hFTs were expanded, had their karyotype analyzed, were characterized by flow cytometry and underwent <it>in vitro </it>adipogenic, chondrogenic, osteogenic, and myogenic differentiation.</p> <p>Results</p> <p>Here we show for the first time that hFTs, which are discarded after some gynecological procedures, are a rich additional source of MSCs, which we designated as <it>human tube MSCs </it>(htMSCs).</p> <p>Conclusion</p> <p>Human tube MSCs can be easily isolated, expanded <it>in vitro</it>, present a mesenchymal profile and are able to differentiate into muscle, fat, cartilage and bone <it>in vitro</it>.</p

    Bacteriocin production by Escherichia coli during biofilm development

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    Escherichia coli is a highly versatile bacterium ranging from commensal to intestinal pathogen, and is an important foodborne pathogen. E. coli species are able to prosper in multispecies biofilms and secrete bacteriocins that are only toxic to species/strains closely related to the producer strain. In this study, 20 distinct E. coli strains were characterized for several properties that confer competitive advantages against closer microorganisms by assessing the biofilm-forming capacity, the production of antimicrobial molecules, and the production of siderophores. Furthermore, primer sets for E. coli bacteriocins–colicins were designed and genes were amplified, allowing us to observe that colicins were widely distributed among the pathogenic E. coli strains. Their production in the planktonic phase or single-species biofilms was uncommon. Only two E. coli strains out of nine biofilm-forming were able to inhibit the growth of other E. coli strains. There is evidence of larger amounts of colicin being produced in the late stages of E. coli biofilm growth. The decrease in bacterial biomass after 12 h of incubation indicates active type I colicin production, whose release normally requires E. coli cell lysis. Almost all E. coli strains were siderophore-producing, which may be related to the resistance to colicin as these two molecules may use the same transporter system. Moreover, E. coli CECT 504 was able to coexist with Salmonella enterica in dual-species biofilms, but Shigella dysenteriae was selectively excluded, correlating with high expression levels of colicin (E, B, and M) genes observed by real-time PCR.info:eu-repo/semantics/publishedVersio

    Comparison of H. pylori in silico metabolic model predictions with experimental data

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    The Systems Biology approach has been replacing the reductionist view that dominated biology research in the last decades. Present biochemical knowledge and genomic databases allowed the development of metabolic models for several organisms, which, however, are still incomplete. The availability of the genome sequence of H. pylori has allowed the construction of a genome-scale metabolic model for this organism. The purposes of this work were to study the growth of H. pylori in a chemically defined medium, to compare the experimental data obtained with the simulated data supplied by the model and analyse the composition of the in silico media used. Cultures were grown at 37ºC under microaerophilic conditions in Ham´s F-12 medium supplemented with fetal bovine serum. Optical density and the counting of CFU/mL were performed for assessing the growth. OptFlux, a software platform for metabolic engineering, which includes several tools such as flux balance analysis (FBA) was employed for simulate the behavior of wild type H. pylori under the conditions used in vivo. The simultaneous use of both approaches allows to correct the in silico model, and on the other hand, to rationally adjust the medium components present in F-12. For instance pimelate, that has been considered to be essential in the latest metabolic model, is lacking in F-12 and is likely to be redundant in the model. Our future work is not only to improve the genome-scale metabolic model, but also, identify potential targets for design more effective drugs for the inactivation of H. pylori
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