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1.
Clin Gastroenterol Hepatol ; 19(5): 1030-1037, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-32663522

RESUMO

BACKGROUND AND AIM: Etiologies of acute viral hepatitis in high-income countries change with migration of populations, lifestyle changes, and emergence of new pathogens. We analyzed etiologies, characteristics, and outcomes of patients with acute viral hepatitis at a tertiary hospital in Spain. METHODS: We analyzed data from all patients with acute hepatitis (n = 100; 71% male; median age, 42 years; 72% Spanish nationals), older than 16 years, diagnosed in the emergency department of an academic hospital in Barcelona, Spain, from January 2014 through December 2018. Blood samples were collected and patients with serum levels of alanine aminotransferase more than 10-fold the upper limit of normal and markers viral infection were considered to have acute viral hepatitis. We collected clinical information from patients, and samples were analyzed for IgM antibody to hepatitis B (HB) core antigen, HB surface antigen, antibody against hepatitis C virus (HCV), HCV RNA, IgM against hepatitis E virus (HEV), HEV RNA, and IgM against hepatitis A virus (HAV). Patients were followed until resolution of infections or evidence of chronic infection. RESULTS: The most common etiologies of acute hepatitis were HBV infection (28%), HEV infection (18%), HCV infection (17%), and HAV infection (14%). The main risk factors of the cohort were sexual risk contact and intravenous drug use; 79% of cases of HAV had sexual risk behavior. Twenty-nine percent of patients with acute HAV infection and 29% of patients with HBV infection were immigrants to Spain. Fifty-four patients were hospitalized; jaundice and HCV infection were associated with hospital admission. Three patients died (2 from acute liver failure related to acute HBV infection or HBV and HDV co-infection). Chronic infections developed in 5/28 patients (18%) with acute HBV infection and 7/17 patients (41%) with acute HCV infection. CONCLUSIONS: Despite universal vaccination against HBV in Spain, HBV remains the most frequent cause of acute viral hepatitis in our emergency department. Almost one-third of cases of acute HBV and HAV infections were immigrants, possibly from countries with suboptimal vaccination programs. A high proportion of patients with acute hepatitis have HEV infection (18%); acute HAV infection was associated with sexual risk behavior.


Assuntos
Hepatite A , Hepatite C , Hepatite E , Adulto , Feminino , Hepacivirus , Hepatite A/complicações , Hepatite A/epidemiologia , Hepatite E/complicações , Hepatite E/epidemiologia , Humanos , Masculino , Espanha/epidemiologia
2.
PLoS Pathog ; 15(8): e1008016, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31461501

RESUMO

Entamoeba histolytica is a pathogen that during its infective process confronts the host defenses, which damages the amoebic plasma membrane (PM), resulting in the loss of viability. However, it is unknown whether amoebic trophozoites are able to repair their PM when it is damaged. Acid sphingomyelinases (aSMases) have been reported in mammalian cells to promote endocytosis and removal of PM lesions. In this work, six predicted amoebic genes encoding for aSMases were found to be transcribed in the HM1:IMSS strain, finding that the EhaSM6 gene is the most transcribed in basal growth conditions and rendered a functional protein. The secreted aSMase activity detected was stimulated by Mg+2 and inhibited by Co+2. Trophozoites that overexpress the EhaSM6 gene (HM1-SM6HA) exhibit an increase of 2-fold in the secreted aSMase activity. This transfectant trophozoites exposed to pore-forming molecules (SLO, Magainin, ß-Defensin 2 and human complement) exhibited an increase from 6 to 25-fold in the secreted aSMase activity which correlated with higher amoebic viability in a Ca+2 dependent process. However, other agents that affect the PM such as hydrogen peroxide also induced an increase of secreted aSMase, but to a lesser extent. The aSMase6 enzyme is N- and C-terminal processed. Confocal and transmission electron microscopy showed that trophozoites treated with SLO presented a migration of lysosomes containing the aSMase towards the PM, inducing the formation of membrane patches and endosomes in the control strain. These cellular structures were increased in the overexpressing strain, indicating the involvement of the aSMase6 in the PM injury repair. The pore-forming molecules induced an increase in the expression of EhaSM1, 2, 5 and 6 genes, meanwhile, hydrogen peroxide induced an increase in all of them. In all the conditions evaluated, the EhaSM6 gene exhibited the highest levels of induction. Overall, these novel findings show that the aSMase6 enzyme from E. histolytica promotes the repair of the PM damaged with pore-forming molecules to prevent losing cell integrity. This novel system could act when encountered with the lytic defense systems of the host.


Assuntos
Membrana Celular/fisiologia , Entamoeba histolytica/enzimologia , Entamebíase/parasitologia , Esfingomielina Fosfodiesterase/metabolismo , Trofozoítos/metabolismo , Cálcio/metabolismo , Entamebíase/metabolismo , Humanos , Esfingomielina Fosfodiesterase/genética , Trofozoítos/crescimento & desenvolvimento
3.
Antonie Van Leeuwenhoek ; 114(2): 209-221, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33394209

RESUMO

Entamoeba histolytica represents a useful model in parasitic organisms due to its complex genomic organization and survival mechanisms. To counteract pathogenic organisms, it is necessary to characterize their molecular biology to design new strategies to combat them. In this report, we investigated a less-known genetic element, short interspersed nuclear element 2 (SINE2), that is present in this ameba and is highly transcribed and polyadenylated. In this study, we show that in two different nonvirulent strains of E. histolytica, SINE2 is differentially processed into two transcript fragments, that is, a full-length 560-nt fragment and a shorter 393-nt fragment bearing an approximately 18-nt polyadenylation tail. Sequence analysis of the SINE2 transcript showed that a Musashi-like protein may bind to it. Also, two putative Musashi-like sequences were identified on the transcript. Semiquantitative expression analysis of the two Musashi-like proteins identified in the E. histolytica genome (XP_648918 and XP_649094) showed that XP_64094 is overexpressed in the nonvirulent strains tested. The information available in the literature and the results presented in this report indicate that SINE2 may affect other genes, as observed with the epigenetic silencing of the G3 strain, by an antisense mechanism or via RNA-protein interactions that may ultimately be involved in the phenotype of nonvirulent strains of E. histolytica.


Assuntos
Entamoeba histolytica , Poliadenilação , Entamoeba histolytica/genética
4.
Antonie Van Leeuwenhoek ; 112(2): 167-177, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30099683

RESUMO

Oxidative stress is a key regulator in many cellular processes but also an important burden for living organisms. The source of oxidative damage usually is difficult to measure and assess with analytical tools or chemical indicators. One major limitation is to discriminate the presence of secondary oxidant molecules derived from the cellular metabolism after exposure to the oxidant or the scavenging capacity of reactive oxygen species by cells. Using a whole-cell reporter system based on an optimized HyPer2 protein for Escherichia coli expression, we demonstrate that, as previously shown for eukaryotic organisms, the effect at the transcriptional level of hydrogen peroxide can be monitored in vivo using flow cytometry of bacterial cells without the need of a direct analytical measurement. In this approach, we generated two different HyPer2 expression systems, one that is induced by IPTG and a second one that is induced by oxidative stress responsive promoters to control the expression of the HyPer2 protein and the exposure of higher H2O2 concentrations that has been shown to activate oxidative response genes. Both systems showed that the pathway that leads to the generation of H2O2 in vivo can be traced from H2O2 exposure. Our results indicate that hydrogen peroxide pulses can be readily detected in E. coli cells by a defined fluorescence signature that is H2O2 concentration-dependent. Our findings indicate that although less sensitive than purified protein or expressed in eukaryotic cells, HyPer2 is a good bacterial sensor for H2O2. As proof of concept, this system was used to trace the oxidative capacity of Toluidine Blue O showing that oxidative stress and redox imbalance is generated inside the cell. This system is expanding the repertoire of whole cell probes available for tracing cellular stress in bacteria.


Assuntos
Proteínas de Bactérias/metabolismo , Escherichia coli/química , Escherichia coli/metabolismo , Fluorometria/métodos , Proteínas Luminescentes/metabolismo , Estresse Oxidativo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Genes Reporter/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Proteínas Luminescentes/química , Proteínas Luminescentes/genética , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/química , Espécies Reativas de Oxigênio/metabolismo
5.
Exp Parasitol ; 187: 86-92, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29476758

RESUMO

Entamoeba histolytica genetic organization and genome structure is complex and under intense research. The genome is fully sequenced, and several tools have been developed for the molecular study of this organism. Nevertheless, good protein tracking tags that are easy to measure and image, like the fluorescent proteins are lacking. In this report, we codon-optimized the red fluorescent protein from the coral Discosoma striata (DsRFP) for its use in E. histolytica and demonstrated functionality in vivo. We envision that this protein can be widely used for the development of transcriptional reporter systems and protein-tagging applications.


Assuntos
Entamoeba histolytica/metabolismo , Substâncias Luminescentes/metabolismo , Proteínas Luminescentes/metabolismo , Animais , Antozoários/química , Clonagem Molecular , Códon/fisiologia , Entamoeba histolytica/genética , Entamoeba histolytica/patogenicidade , Citometria de Fluxo , Expressão Gênica , Proteínas Luminescentes/genética , Microscopia Confocal , Plasmídeos/genética , Plasmídeos/metabolismo , Reação em Cadeia da Polimerase , Mapeamento por Restrição , Esfingomielina Fosfodiesterase/genética , Virulência , Proteína Vermelha Fluorescente
6.
Exp Parasitol ; 194: 38-44, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30253133

RESUMO

Amoebiasis is a worldwide health problem caused by the pathogen Entamoeba histolytica. Several virulence factors have been implicated in host invasion, immune evasion, and tissue damage. There are still new factors that remain to be elucidated and characterized. In this work, we obtained amoebic transfectants overexpressing three of the neutral sphingomyelinase enzymes encoded in the E. histolytica genome. The EhnSM3 overexpression induced an increase in hemolytic and cytotoxic activities, besides an increase in gene expression of amoebapore A, B, and C. Meanwhile the EhnSM1 and EhnSM2 overexpression caused an increase in cytopathic activity. In all the neutral sphingomyelinases overexpressing strains, the gene expression levels for cysteine proteinase 5, adhesin 112 and, heavy and light Gal/GalNAc lectin subunits were not affected. We propose that the increase of cytotoxic and lytic effect of EhnSM3 overexpressed strain can be related to the sum of the effect of EhnSM3 plus amoebapores, in a process cell contact-dependent or as mediator by inducing the gene expression of amoebapores enabling a link between EhnSM3 with the virulence phenotype in E. histolytica. Our results suggest a differential role for neutral sphingomyelinases in E. histolytica virulence.


Assuntos
Entamoeba histolytica/patogenicidade , Esfingomielina Fosfodiesterase/metabolismo , Animais , Cães , Entamoeba histolytica/enzimologia , Entamoeba histolytica/genética , Eritrócitos/metabolismo , Expressão Gênica , Genoma de Protozoário , Hemólise , Humanos , Células Madin Darby de Rim Canino , Esfingomielina Fosfodiesterase/genética , Esfingomielina Fosfodiesterase/isolamento & purificação , Esfingomielinas/metabolismo , Transfecção , Virulência
7.
Optom Vis Sci ; 95(12): 1142-1148, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30451801

RESUMO

SIGNIFICANCE: This is a prospective observational investigation that studies the repeatability of several outcomes obtained with the Keratron Scout in healthy and keratoconic corneas. In addition, we have been able to determine the "noise" values of the instrument, which can be very useful when evaluating possible progression in keratoconus (KCN). PURPOSE: The purpose of this study was to evaluate the repeatability of several anterior curvature metrics provided by a portable and handheld Placido disk-based topographer in healthy and keratoconic eyes. METHODS: One eye from 50 keratoconic patients and 50 eyes from healthy patients were included in this prospective observational study. Two consecutive sessions (with three scans per session) were performed, and the following parameters were analyzed with a Keratron Scout topographer: flat keratometry, steep keratometry, flat corneal axis, corneal astigmatism, and flat and steep asphericities. In addition, in the KCN cohort, indices derived from the Cone Location and Magnitude Index were also recorded. Intrasession (first session, all three measurements) and intersession (one measurement from each session, selected randomly) statistics were calculated. The following variables were calculated: within-subject standard deviation, coefficient of repeatability (R), coefficient of variation, and intraclass correlation coefficient (ICC). RESULTS: In healthy eyes, the intrasession and intersession ICCs were high (0.947 to 0.999), and for both flat keratometry and steep keratometry, the within-subject standard deviation was 0.08 and R was 0.24 diopters. Repeatability was slightly lower in the KCN group, but the ICC was greater than 0.95, whereas the R for flat keratometry was 0.41 diopters. CONCLUSIONS: The Keratron Scout provides repeatable measures for the studied metrics in healthy and keratoconic eyes.


Assuntos
Córnea/patologia , Topografia da Córnea/instrumentação , Ceratocone/diagnóstico , Adolescente , Adulto , Astigmatismo , Biometria/instrumentação , Estudos de Coortes , Feminino , Voluntários Saudáveis , Humanos , Masculino , Estudos Prospectivos , Reprodutibilidade dos Testes , Adulto Jovem
8.
Arch Microbiol ; 197(6): 815-21, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25983135

RESUMO

Bacterial reporter assays are powerful tools used to study the effect of different compounds that affect the physiology of cellular processes. Most bacterial reporters are luciferase based and can be monitored in real time. In the present study we designed and implemented two sets of Escherichia coli bacterial reporter assays, using a multicopy plasmid system. Each reporter strain was constructed using either green fluorescent protein or ß-galactosidase (LacZ) proteins. The designed reporter strains are capable of responding in a specific manner to molecules that either oxidative stress, or membrane, protein, or DNA damage. In order to respond to the desired stimulus, promoter sequences from E. coli were used. These sequences correspond to the promoter of the major catalase (KatG) activated with cellular oxidative damage, the promoter of the ß-hydroxydecanoyl-ACP dehydrase (FabA) which is activated with membrane perturbation, the promoter of DNA recombinase (RecA) which is activated by DNA lesions. For protein misfolding, the promoter of the heat-shock responsive chaperon (DnaK) was used. Our constructs displayed activation to damage from specific stimuli, and low response to nonspecific stimuli was detected. Our results suggest that these types of bacterial reporter strains can be used in semiquantitative (fluorometric) and qualitative (ß-galactosidase activity) studies of different xenobiotic substances and pollutants.


Assuntos
Técnicas Biossensoriais , Colorimetria/métodos , Escherichia coli , Proteínas de Fluorescência Verde , Plasmídeos , Sequência de Bases , Dano ao DNA/fisiologia , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Estresse Oxidativo/fisiologia , Regiões Promotoras Genéticas , beta-Galactosidase/genética , beta-Galactosidase/metabolismo
9.
Molecules ; 20(7): 12436-49, 2015 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-26184131

RESUMO

In vitro studies to fourteen previously synthesized chromone-tetrazoles and four novel fluorine-containing analogs were conducted against pathogenic protozoan (Entamoeba histolytica), pathogenic bacteria (Pseudomonas aeruginosa, and Staphylococcus aureus), and human fungal pathogens (Sporothrix schenckii, Candida albicans, and Candida tropicalis), which have become in a serious health problem, mainly in tropical countries.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antiprotozoários/farmacologia , Cromonas/farmacologia , Tetrazóis/farmacologia , Antibacterianos/síntese química , Antifúngicos/síntese química , Antiprotozoários/síntese química , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Candida albicans/patogenicidade , Candida tropicalis/efeitos dos fármacos , Candida tropicalis/crescimento & desenvolvimento , Candida tropicalis/patogenicidade , Cromonas/síntese química , Entamoeba histolytica/efeitos dos fármacos , Entamoeba histolytica/crescimento & desenvolvimento , Entamoeba histolytica/patogenicidade , Flúor/química , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/patogenicidade , Sporothrix/efeitos dos fármacos , Sporothrix/crescimento & desenvolvimento , Sporothrix/patogenicidade , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/patogenicidade , Tetrazóis/síntese química
10.
Mol Biochem Parasitol ; 260: 111647, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-39002760

RESUMO

Entamoeba histolytica, an intestinal parasite of global significance, poses substantial health risks with its associated high morbidity and mortality rates. Despite the current repertoire of molecular tools for the study of gene function in, the regulatory mechanisms governing its pathogenicity remain largely unexplored. This knowledge gap underscores the need to elucidate key genetic determinants orchestrating cellular functions critical to its virulence. Previously, our group generated an avirulent strain, termed UG10, with the same genetic background as the HM1:IMSS strain. UG10 strain, despite showing normal expression levels of well-known virulence factors, was unable to perform in-vitro and in-vivo activities related to amoebic virulence. In this study, we aimed to uncover the genome-wide modifications that rendered the avirulent phenotype of the UG10 strain through whole-genome sequencing. As a complementary approach, we conducted Methylated DNA Immunoprecipitation coupled with sequencing (MeDIP-seq) analysis on both the highly virulent HM1:IMSS strain and the low-virulence UG10 strain to uncover the genome-wide methylation profile. These dual methodologies revealed two aspects of the UG10 avirulent strain. One is the random integration of fragments from the ribosomal gene cluster and tRNA genes, ranging from 120 to 400 bp; and secondly, a clear, enriched methylation profile in the coding and non-coding strand relative to the start codon sequence in genes encoding small GTPases, which is associated with the previously described avirulent phenotype. This study provides the foundation to explore other genetic and epigenetic regulatory circuitries in E. histolytica and novel targets to understand the pathogenic mechanism of this parasite.

11.
Pathogens ; 12(3)2023 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-36986411

RESUMO

Entamoeba histolytica virulence results from complex host-parasite interactions implicating multiple amoebic components (e.g., Gal/GalNAc lectin, cysteine proteinases, and amoebapores) and host factors (microbiota and immune response). UG10 is a strain derived from E. histolytica virulent HM-1:IMSS strain that has lost its virulence in vitro and in vivo as determined by a decrease of hemolytic, cytopathic, and cytotoxic activities, increased susceptibility to human complement, and its inability to form liver abscesses in hamsters. We compared the transcriptome of nonvirulent UG10 and its parental HM-1:IMSS strain. No differences in gene expression of the classical virulence factors were observed. Genes downregulated in the UG10 trophozoites encode for proteins that belong to small GTPases, such as Rab and AIG1. Several protein-coding genes, including iron-sulfur flavoproteins and heat shock protein 70, were also upregulated in UG10. Overexpression of the EhAIG1 gene (EHI_180390) in nonvirulent UG10 trophozoites resulted in augmented virulence in vitro and in vivo. Cocultivation of HM-1:IMSS with E. coli O55 bacteria cells reduced virulence in vitro, and the EhAIG1 gene expression was downregulated. In contrast, virulence was increased in the monoxenic strain UG10, and the EhAIG1 gene expression was upregulated. Therefore, the EhAIG1 gene (EHI_180390) represents a novel virulence determinant in E. histolytica.

12.
PeerJ ; 11: e16309, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37849831

RESUMO

The complex metabolism of Escherichia coli has been extensively studied, including its response to oxygen availability. The ArcA/B two-component system (TCS) is the key regulator for the transition between these two environmental conditions and has been thoroughly characterized using genetic and biochemical approaches. Still, to date, limited structural data is available. The breakthrough provided by AlphaFold2 in 2021 has brought a reliable tool to the scientific community for assessing the structural features of complex proteins. In this report, we analyzed the structural aspects of the ArcA/B TCS using AlphaFold2 models. The models are consistent with the experimentally determined structures of ArcB kinase. The predicted structure of the dimeric form of ArcB is consistent with the extensive genetic and biochemical data available regarding mechanistic signal perception and regulation. The predicted interaction of the dimeric form of ArcB with its cognate response regulator (ArcA) is also consistent with both the forward and reverse phosphotransfer mechanisms. The ArcB model was used to detect putative binding cavities to anaerobic metabolites, encouraging testing of these predictions experimentally. Finally, the highly accurate models of other ArcB homologs suggest that different experimental approaches are needed to determine signal perception in kinases lacking the PAS domain. Overall, ArcB is a kinase with features that need further testing, especially in determining its crystal structure under different conditions.


Assuntos
Proteínas de Escherichia coli , Anaerobiose , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/genética , Dimerização , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Modelos Teóricos , Fosforilação , Proteínas Quinases/genética , Proteínas Repressoras/genética
13.
Biology (Basel) ; 11(6)2022 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-35741397

RESUMO

We used light and confocal microscopy to visualize bacteria in leaf and bract cells of more than 30 species in 18 families of seed plants. Through histochemical analysis, we detected hormones (including ethylene and nitric oxide), superoxide, and nitrogenous chemicals (including nitric oxide and nitrate) around bacteria within plant cells. Bacteria were observed in epidermal cells, various filamentous and glandular trichomes, and other non-photosynthetic cells. Most notably, bacteria showing nitrate formation based on histochemical staining were present in glandular trichomes of some dicots (e.g., Humulus lupulus and Cannabis sativa). Glandular trichome chemistry is hypothesized to function to scavenge oxygen around bacteria and reduce oxidative damage to intracellular bacterial cells. Experiments to assess the differential absorption of isotopic nitrogen into plants suggest the assimilation of nitrogen into actively growing tissues of plants, where bacteria are most active and carbohydrates are more available. The leaf and bract cell endosymbiosis types outlined in this paper have not been previously reported and may be important in facilitating plant growth, development, oxidative stress resistance, and nutrient absorption into plants. It is unknown whether leaf and bract cell endosymbioses are significant in increasing the nitrogen content of plants. From the experiments that we conducted, it is impossible to know whether plant trichomes evolved specifically as organs for nitrogen fixation or if, instead, trichomes are structures in which bacteria easily colonize and where some casual nitrogen transfer may occur between bacteria and plant cells. It is likely that the endosymbioses seen in leaves and bracts are less efficient than those of root nodules of legumes in similar plants. However, the presence of endosymbioses that yield nitrate in plants could confer a reduced need for soil nitrogen and constitute increased nitrogen-use efficiency, even if the actual amount of nitrogen transferred to plant cells is small. More research is needed to evaluate the importance of nitrogen transfer within leaf and bract cells of plants.

14.
AMB Express ; 12(1): 2, 2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-34989906

RESUMO

The presence of pollutants in soil and water has given rise to diverse analytical and biological approaches to detect and measure contaminants in the environment. Using bacterial cells as reporter strains represents an advantage for detecting pollutants present in soil or water samples. Here, an Escherichia coli reporter strain expressing a chromoprotein capable of interacting with soil or water samples and responding to DNA damaging compounds is validated. The reporter strain generates a qualitative signal and is based on the expression of the coral chromoprotein AmilCP under the control of the recA promoter. This strain can be used simply by applying soil or water samples directly and rendering activation upon DNA damage. This reporter strain responds to agents that damage DNA (with an apparent detection limit of 1 µg of mitomycin C) without observable response to membrane integrity damage, protein folding or oxidative stress generating agents, in the latter case, DNA damage was observed. The developed reporter strain reported here is effective for the detection of DNA damaging agents present in soils samples. In a proof-of-concept analysis using soil containing chromium, showing activation at 15.56 mg/L of Cr(VI) present in soil and leached samples and is consistent with Cr(III) toxicity at high concentrations (130 µg). Our findings suggest that chromogenic reporter strains can be applied for simple screening, thus reducing the number of samples requiring analytical techniques.

15.
PeerJ ; 10: e13772, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35880217

RESUMO

Organisms need mechanisms to perceive the environment and respond accordingly to environmental changes or the presence of hazards. Transcription factors (TFs) are required for cells to respond to the environment by controlling the expression of genes needed. Escherichia coli has been the model bacterium for many decades, and still, there are features embedded in its genome that remain unstudied. To date, 58 TFs remain poorly characterized, although their binding sites have been experimentally determined. This study showed that these TFs have sequence variation at the third codon position G+C content but maintain the same Codon Adaptation Index (CAI) trend as annotated functional transcription factors. Most of these transcription factors are in areas of the genome where abundant repetitive and mobile elements are present. Sequence divergence points to groups with distinctive sequence signatures but maintaining the same type of DNA binding domain. Finally, the analysis of the promoter sequences of the 58 TFs showed A+T rich regions that agree with the features of horizontally transferred genes. The findings reported here pave the way for future research of these TFs that may uncover their role as spare factors in case of lose-of-function mutations in core TFs and trace back their evolutionary history.


Assuntos
Escherichia coli , Fatores de Transcrição , Fatores de Transcrição/genética , Escherichia coli/genética , Evolução Biológica , Regiões Promotoras Genéticas/genética , Códon
16.
Curr Microbiol ; 62(1): 301-6, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20640424

RESUMO

Antimicrobial peptides are widely distributed in nature; they play important roles in several aspects of innate immunity and may provide a basis for the design of novel therapeutic agents. In this study, C-amidated tritrpticin, a 13 amino acid tryptophan-rich antimicrobial peptide derived from a porcine cathelicidin, was tested against Trichomonas vaginalis, a protozoan that causes a serious non-viral sexually transmitted disease associated with preterm birth, low birth weight, and high risk of HIV-1 infection. Tritrpticin was selected due to its reasonably easy synthesis and because analogs with lower toxicity may be designed. Our results show that tritrpticin-NH(2) at either 100 or 200 µg/ml (52.5 or 105 µM) clearly reduces the viability and growth of Trichomonas vaginalis. Together with tritrpticin-NH(2), sodium bicarbonate further limited trichomonad growth. Additionally, a low concentration of metronidazole (5.8 µM), the most commonly used medication for Trichomonas vaginalis, was more effective against the growth of the parasite when it was combined with tritrpticin-NH(2).


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Antiprotozoários/farmacologia , Oligopeptídeos/farmacologia , Trichomonas vaginalis/efeitos dos fármacos , Sinergismo Farmacológico , Feminino , Humanos , Metronidazol/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Testes de Sensibilidade Parasitária , Bicarbonato de Sódio/farmacologia , Trichomonas vaginalis/crescimento & desenvolvimento , Trichomonas vaginalis/fisiologia
17.
Eye Contact Lens ; 37(6): 381-5, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21983547

RESUMO

OBJECTIVE: The aim was to report three cases of severe bilateral epithelial edema (central corneal clouding [CCC]) in association with ClearKone SynergEyes hybrid contact lenses for the vision rehabilitation of keratoconus. METHODS: Retrospective case series of six eyes of three patients that developed CCC with ClearKone SynergEyes hybrid contact lens wear shortly after beginning to wear those lenses. RESULTS: Severe CCC was diagnosed on removal of the lenses. Despite attempts to modify the parameters of the lenses to reduce edema, two patients discontinued lens wear entirely, and one patient was able to wear lenses only on a limited basis. CONCLUSIONS: Different degrees of CCC have been reported with the use of polymethyl methacrylate lenses; however, the condition may also occur with the use of ClearKone SynergEyes lenses. Although the lenses may provide good subjective responses, careful observation of the corneal response after 5 hrs of wear is advised.


Assuntos
Lentes de Contato/efeitos adversos , Edema da Córnea/etiologia , Ceratocone/terapia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Acuidade Visual
18.
Cont Lens Anterior Eye ; 44(2): 289-329, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33775381

RESUMO

The medical use of contact lenses is a solution for many complex ocular conditions, including high refractive error, irregular astigmatism, primary and secondary corneal ectasia, disfiguring disease, and ocular surface disease. The development of highly oxygen permeable soft and rigid materials has extended the suitability of contact lenses for such applications. There is consistent evidence that bandage soft contact lenses, particularly silicone hydrogel lenses, improve epithelial healing and reduce pain in persistent epithelial defects, after trauma or surgery, and in corneal dystrophies. Drug delivery applications of contact lens hold promise for improving topical therapy. Modern scleral lens practice has achieved great success for both visual rehabilitation and therapeutic applications, including those requiring retention of a tear reservoir or protection from an adverse environment. This report offers a practical and relevant summary of the current evidence for the medical use of contact lenses for all eye care professionals including optometrists, ophthalmologists, opticians, and orthoptists. Topics covered include indications for use in both acute and chronic conditions, lens selection, patient selection, wear and care regimens, and recommended aftercare schedules. Prevention, presentation, and management of complications of medical use are reviewed.


Assuntos
Lentes de Contato Hidrofílicas , Distrofias Hereditárias da Córnea , Erros de Refração , Humanos , Esclera , Acuidade Visual
19.
Exp Parasitol ; 125(3): 279-85, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20138872

RESUMO

A novel neutral sphingomyelinase (nSMase) was characterized in Entamoeba histolytica trophozoites. SMase, a sphingomyelin-specific form of phospholipase C, catalyzes the hydrolysis of sphingomyelin to ceramide and phosphorylcholine. Three amebic putative nSMase genes were found to be actively transcribed. Mg(2+)-independent nSMase activity in the soluble fraction of the trophozoites was stimulated by Mn(2+) and partially inhibited by Zn(2+). nSMase activity of the recombinant protein EhnSM1, increased 4.5-fold in the presence of 0.5mM Mn(2+), and abolished by 5mM Zn(2+). A dose-dependent inhibition of rEhnSM1 was observed with scyphostatin, a specific inhibitor of nSMases. The EhnSM1 and EhnSM3 were detected in the soluble fraction of the amebic lysate as 35-37kDa proteins by western blot analysis. Immunofluorescence assay showed that the overexpressed HA-tagged EhnSM1 and EhnSM3 were localized to the cytosol. The biological role of these novel E. histolytica nSMases described in this work remains to be determined.


Assuntos
Entamoeba histolytica/enzimologia , Entamoeba histolytica/genética , Esfingomielina Fosfodiesterase/genética , Esfingomielina Fosfodiesterase/metabolismo , Amidas/farmacologia , Sequência de Aminoácidos , Western Blotting , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Técnica Indireta de Fluorescência para Anticorpo , Dados de Sequência Molecular , Pironas/farmacologia , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Esfingomielina Fosfodiesterase/antagonistas & inibidores , Trofozoítos/enzimologia
20.
Cir Cir ; 88(2): 128-136, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32116313

RESUMO

Trauma to peripheral vascular organ is a very frequent condition during military conflicts. Fortunately, comprehensive understanding of local and systemic pathophysiology, in addition to the development of innovative surgical techniques and technological advances, have improved the outcome regarding to survival and anatomic and functional conservation of the limbs. In this manuscript, we perform an historical and state of the art review related to the approach of the peripheral vascular trauma, on the basis of an heroical episode from the Mexico City's Campaign, during North American invasion 1846-1848: the defense of Chapultepec's Castle by cadet Agustin Melgar.


El trauma del órgano vascular periférico es una condición muy frecuente en los conflictos militares. Por fortuna, la comprensión integral de la fisiopatología local y sistémica, en adición al desarrollo de técnicas quirúrgicas innovadoras y avances tecnológicos, ha mejorado el pronóstico relativo a la sobrevida y la conservación anatómica y funcional de las extremidades. En este trabajo se hace una revisión histórica y del estado actual del abordaje del trauma vascular periférico, sobre la base de un episodio heroico de la Campaña por la Ciudad de México durante la invasión norteamericana de 1846-1848: la defensa del Castillo de Chapultepec por el cadete Agustín Melgar.


Assuntos
Vasos Sanguíneos/lesões , Militares , Procedimentos Cirúrgicos Vasculares/história , Lesões Relacionadas à Guerra/cirurgia , História do Século XIX , Humanos , México
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