RESUMO
Antimicrobial proteins and peptides are an alternative to current antibiotics. Here, we report an antimicrobial activity in a low-molecular-weight protein secreted naturally by Streptomyces lividans TK24 when glucose or glycerol were used as carbon sources. The antimicrobial activity was demonstrated against Bacillus subtilis, Bacillus cereus, Kokuria rhizophila, Clostridium sporogenes and Clavibacter michiganensis, causal pathogen of tomato bacterial canker; one of the most destructive bacterial diseases of this crop. The protein fraction with antimicrobial activity was identified and quantified by LC-MS/MS. From a total of 155 proteins, 11 were found to be within the range of 11.3-13.9 kDa of which four proteins were selected by functional analysis as possibly responsible for the antimicrobial activity. Protein fractionation, correlation analysis between antimicrobial activity and abundance of selected proteins, as well as transcriptional expression analysis, indicate that 50S ribosomal protein L19 is the main candidate responsible for antimicrobial activity.
Assuntos
Anti-Infecciosos , Micrococcaceae , Solanum lycopersicum , Streptomyces lividans , Cromatografia Líquida , Espectrometria de Massas em Tandem , Solanum lycopersicum/microbiologia , Anti-Infecciosos/farmacologiaRESUMO
The coronavirus SARS-CoV-2 has caused a pandemic with > 550 millions of cases and > 6 millions of deaths worldwide. Medical management of COVID-19 relies on supportive care as no specific targeted therapies are available yet. Given its devastating effects on the economy and mental health, it is imperative to develop novel antivirals. An ideal candidate will be an agent that blocks the early events of viral attachment and cell entry, thereby preventing viral infection and spread. This work reports functionalized titanium dioxide (TiO2)-based nanoparticles adsorbed with flavonoids that block SARS-CoV-2 entry and fusion. Using molecular docking analysis, two flavonoids were chosen for their specific binding to critical regions of the SARS-CoV-2 spike glycoprotein that interacts with the host cell angiotensin-converting enzyme-2 (ACE-2) receptor. These flavonoids were adsorbed onto TiO2 functionalized nanoparticles (FTNP). This new nanoparticulate compound was assayed in vitro against two different coronaviruses; HCoV 229E and SARS-CoV-2, in both cases a clear antiviral effect was observed. Furthermore, using a reporter-based cell culture model, a potent antiviral activity is demonstrated. The adsorption of flavonoids to functionalized TiO2 nanoparticles induces a ~ threefold increase of that activity. These studies also indicate that FTNP interferes with the SARS-CoV-2 spike, impairing the cell fusion mechanism. KEY POINTS/HIGHLIGHTS: ⢠Unique TiO2 nanoparticles displaying flavonoid showed potent anti-SARS-CoV-2 activity. ⢠The nanoparticles precisely targeting SARS-CoV-2 were quantitatively verified by cell infectivity in vitro. ⢠Flavonoids on nanoparticles impair the interactions between the spike glycoprotein and ACE-2 receptor.
Assuntos
Tratamento Farmacológico da COVID-19 , Nanopartículas , Antivirais/química , Antivirais/farmacologia , Flavonoides/farmacologia , Humanos , Simulação de Acoplamento Molecular , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , TitânioRESUMO
In an earlier work on lovastatin production by Aspergillus terreus, we found that reactive oxygen species (ROS) concentration increased to high levels precisely at the start of the production phase (idiophase) and that these levels were sustained during all idiophase. Moreover, it was shown that ROS regulate lovastatin biosynthesis. ROS regulation has also been reported for aflatoxins. It has been suggested that, due to their antioxidant activity, aflatoxins are regulated and synthesized like a second line of defense against oxidative stress. To study the possible ROS regulation of other industrially important secondary metabolites, we analyzed the relationship between ROS and penicillin biosynthesis by Penicillium chrysogenum and cephalosporin biosynthesis by Acremonium chrysogenum. Results revealed a similar ROS accumulation in idiophase in penicillin and cephalosporin fermentations. Moreover, when intracellular ROS concentrations were decreased by the addition of antioxidants to the cultures, penicillin and cephalosporin production were drastically reduced. When intracellular ROS were increased by the addition of exogenous ROS (H2O2) to the cultures, proportional increments in penicillin and cephalosporin biosyntheses were obtained. It was also shown that lovastatin, penicillin, and cephalosporin are not antioxidants. Taken together, our results provide evidence that ROS regulation is a general mechanism controlling secondary metabolism in fungi.
Assuntos
Acremonium/metabolismo , Cefalosporinas/biossíntese , Penicilinas/biossíntese , Penicillium chrysogenum/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Acremonium/efeitos dos fármacos , Vias Biossintéticas , Fermentação , Regulação Fúngica da Expressão Gênica , Peróxido de Hidrogênio/farmacologia , Penicillium chrysogenum/efeitos dos fármacos , Espécies Reativas de Oxigênio/farmacologia , Metabolismo SecundárioRESUMO
Three different transformation strategies were tested and compared in an attempt to facilitate and improve the genetic transformation of Acremonium chrysogenum, the exclusive producer of the pharmaceutically relevant ß-lactam antibiotic cephalosporin C. We investigated the use of high-voltage electric pulse to transform germinated conidia and young mycelium and compared these procedures with traditional PEG-mediated protoplast transformation, using phleomycin resistance as selection marker in all cases. The effect of the field strength and capacitance on transformation frequency and cell viability was evaluated. The electroporation of germinated conidia and young mycelium was found to be appropriate for transforming A. chrysogenum with higher transformation efficiencies than those obtained with the conventional protoplast-based transformation procedures. The developed electroporation strategy is fast, simple to perform, and highly reproducible and avoids the use of chemicals toxic to cells. Electroporation of young mycelium represents an alternative method for transformation of fungal strains with reduced or no sporulation, as often occurs in laboratory-developed strains in the search for high-yielding mutants for industrial bioprocesses.
Assuntos
Acremonium/genética , Eletroporação/métodos , Transformação Genética , Acremonium/efeitos dos fármacos , Acremonium/metabolismo , Cefalosporinas/biossíntese , Farmacorresistência Bacteriana , Viabilidade Microbiana , Micélio/efeitos dos fármacos , Micélio/genética , Micélio/metabolismo , Fleomicinas/farmacologia , Protoplastos/fisiologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/genética , Esporos Fúngicos/metabolismoRESUMO
OBJECTIVES.: To evaluate the protective effect of Zea mays L., purple variety (purple corn) against inflammatory response and osteoarticular damage in rats with experimental arthritis. MATERIALS AND METHODS.: Sixty-five Holtzman rats were used, assigned to seven groups: G1 (n=5): control; G2 (n=10): pristane (PIA) + distilled water; G3 (n=10): PIA + methotrexate 0.1 mg/kg; G4 (n=10): PIA + indomethacin 0.6 mg/kg; G5 (n=10): PIA + Zea mays 100 mg/kg; G6 (n=10): PIA + Zea mays 1000 mg/kg, and G7 (n=10): PIA + methotrexate 0.1 mg/kg + Zea mays 1000 mg/kg. Treatments were administered by orogastric cannula daily for 21 days; pristane was administered subdermal only on day 1. Volume of hind leg was recorded with a digital plethysmometer. The radiological analysis of the legs was evaluated according to the modified Clark criteria. RESULTS.: The percentage of inflammation at the end of the experiment was: (G1) 1.50 ± 0.5; (G2) 13.73 ± 8.4; (G3) 14.76 ± 8.8; (G4) 14.22 ± 9.0; (G5) 10.81 ± 9.1; (G6) 5.31 ± 1.4; (G7) 6.38 ± 0.5. The radiological scores of the affected areas were: (G1) 0.6; (G2) 3.5; (G3) 0.6; (G4) 1.7; (G5) 1.9; (G6) 1.4; (G7) 1.0. Only the groups Zea mays L. 1000 mg/kg and methotrexate + Zea mays L. 1000 mg/kg showed a significantly lower inflammatory response (p<0.05) and showed significantly lower joint scores in relation to PIA. CONCLUSIONS.: Zea mays L. (purple corn) reduces the inflammatory process and radiological modifications of PIA-induced arthritis in rats in a dose-dependent manner.
OBJETIVOS.: Evaluar el efecto protector de Zea mays L. variedad morada (maíz morado) frente a la respuesta inflamatoria y daño osteoarticular en ratas con artritis experimental. MATERIALES Y MÉTODOS.: Se emplearon 65 ratas Holtzman, asignadas en siete grupos: G1 (n=5): control, G2 (n=10): pristane (PIA) + agua destilada, G3 (n=10): PIA + metotrexate 0,1 mg/kg, G4 (n=10): PIA + indometacina 0,6 mg/kg, G5 (n=10): PIA + Zea mays 100 mg/kg, G6 (n=10): PIA + Zea mays 1000 mg/kg y G7 (n=10): PIA + metotrexate 0,1 mg/kg + Zea mays 1000 mg/kg. Los tratamientos fueron administrados mediante cánula orogástrica diariamente durante 21 días; el pristane se administró vía subdérmica solo el día 1. Se registró el volumen de pata trasera con un pletismometro digital. El análisis radiológico de las patas se evaluó según los criterios de Clark modificado. RESULTADOS.: El porcentaje de inflamación al final del experimento fue: (G1) 1,50 ± 0,5, (G2) 13,73 ± 8,4; (G3) 14,76 ± 8,8; (G4) 14.22 ± 9,0; (G5) 10,81 ± 9.1; (G6) 5,31 ± 1.4; (G7) 6,38 ± 0,5. Los puntajes radiológicos de las áreas afectadas fueron: (G1) 0,6; (G2) 3,5; (G3) 0,6; (G4) 1,7; (G5) 1,9; (G6) 1,4; (G7) 1,0. Solo los grupos Zea mays L. 1000 mg/kg y metotrexate + Zea mays L. 1000 mg/kg mostraron una respuesta inflamatoria significativamente menor (p<0,05) y mostraron puntajes articulares significativamente bajos en relación a PIA. CONCLUSIONES.: El Zea mays L. (maíz morado) reduce el proceso inflamatorio y las modificaciones radiológicas de la artritis inducida por PIA en ratas de modo dosis dependiente.
Assuntos
Artrite/prevenção & controle , Fitoterapia , Extratos Vegetais/uso terapêutico , Zea mays , Animais , Doenças Ósseas/prevenção & controle , Modelos Animais de Doenças , Progressão da Doença , Feminino , Ratos , Ratos Sprague-DawleyRESUMO
A successful endodontic treatment requires knowledge of the internal configuration of dental root canals. Most of the people who live in Yucatan are of Maya origin, characterized by a Mongoloid dental pattern. Because of their ethnicity, variations are expected. The purpose of this investigation is to assess the morphological characteristics and variability of this population. One hundred and five extracted first mandibular premolars of Mexican Maya population were analyzed; the sample was obtained from the Oral Surgery Clinic in the School of Dentistry at the Autonomous University of Yucatan with written informed consent. Analyses were performed by means of Cone Beam Computed Tomography. Vertucci´s Type I was the most prevalent configuration with 51.4 %, but 41 cases (39.1 %) presented a radicular groove and a C-shaped canal configuration. Overall, we documented 1, 2, 3, and 4 root canals. Mandibular first premolars are very variable in the Yucatecan population. The variability and frequency of C-shape is similar to mandibular second molars confirming the importance of the ethnic background for the endodontic treatments.
El éxito en el tratamiento endodóntico requiere el conocimiento profundo de la configuración interna del sistema de conductos radiculares. La mayoría de las personas que viven en Yucatán son de origen Maya y poseen el patron dental Mongoloide; por lo tanto, se esperan variaciones debido a su etnicidad. El propósito de esta investigación fue evaluar las características morfológicas y la variabilidad del conducto radicular en la población yucateca. Se analizaron ciento cinco primeros premolars mandibulares extraídos de pacientes provenientes de una muestra Maya mexicana; la muestra fue obtenida de la Clínica de Cirugía Oral de la Facultad de Odontología de la Universidad Autónoma de Yucatán. Con consentimiendo informado escrito. Se utilizaron Tomografías Computarizadas para el análisis de la muestra. La configuración más prevalente fue la Tipo I de Vertucci con 51,4 %. Sin embargo, 41 de 105 casos (39,1 %) presentaron un surco radicular y la configuración en forma de "C". Se documentaron casos con 1, 2, 3 y 4 conductos radiculares. Los primeros premolares mandibulares de la población Yucateca son muy variables. La variabilidad y frecuencia de conductos en forma de "C" concuerda con estudios realizados en segundos molars mandibulares en esta zona confirmando la importancia del origen étnico de las poblaciones para los tratamientos endodónticos.
Assuntos
Humanos , Masculino , Feminino , Dente Pré-Molar/diagnóstico por imagem , Cavidade Pulpar/diagnóstico por imagem , Mandíbula/diagnóstico por imagem , Dente Pré-Molar/anatomia & histologia , Indígenas Norte-Americanos , Tomografia Computadorizada por Raios X , Cavidade Pulpar/anatomia & histologia , Mandíbula/anatomia & histologia , MéxicoRESUMO
RESUMEN Objetivos. Evaluar el efecto protector de Zea mays L. variedad morada (maíz morado) frente a la respuesta inflamatoria y daño osteoarticular en ratas con artritis experimental. Materiales y métodos. Se emplearon 65 ratas Holtzman, asignadas en siete grupos: G1 (n=5): control, G2 (n=10): pristane (PIA) + agua destilada, G3 (n=10): PIA + metotrexate 0,1 mg/kg, G4 (n=10): PIA + indometacina 0,6 mg/kg, G5 (n=10): PIA + Zea mays 100 mg/kg, G6 (n=10): PIA + Zea mays 1000 mg/kg y G7 (n=10): PIA + metotrexate 0,1 mg/kg + Zea mays 1000 mg/kg. Los tratamientos fueron administrados mediante cánula orogástrica diariamente durante 21 días; el pristane se administró vía subdérmica solo el día 1. Se registró el volumen de pata trasera con un pletismometro digital. El análisis radiológico de las patas se evaluó según los criterios de Clark modificado. Resultados. El porcentaje de inflamación al final del experimento fue: (G1) 1,50 ± 0,5, (G2) 13,73 ± 8,4; (G3) 14,76 ± 8,8; (G4) 14.22 ± 9,0; (G5) 10,81 ± 9.1; (G6) 5,31 ± 1.4; (G7) 6,38 ± 0,5. Los puntajes radiológicos de las áreas afectadas fueron: (G1) 0,6; (G2) 3,5; (G3) 0,6; (G4) 1,7; (G5) 1,9; (G6) 1,4; (G7) 1,0. Solo los grupos Zea mays L. 1000 mg/kg y metotrexate + Zea mays L. 1000 mg/kg mostraron una respuesta inflamatoria significativamente menor (p<0,05) y mostraron puntajes articulares significativamente bajos en relación a PIA. Conclusiones. El Zea mays L. (maíz morado) reduce el proceso inflamatorio y las modificaciones radiológicas de la artritis inducida por PIA en ratas de modo dosis dependiente.
ABSTRACT Objectives. To evaluate the protective effect of Zea mays L., purple variety (purple corn) against inflammatory response and osteoarticular damage in rats with experimental arthritis. Materials and Methods. Sixty-five Holtzman rats were used, assigned to seven groups: G1 (n=5): control; G2 (n=10): pristane (PIA) + distilled water; G3 (n=10): PIA + methotrexate 0.1 mg/kg; G4 (n=10): PIA + indomethacin 0.6 mg/kg; G5 (n=10): PIA + Zea mays 100 mg/kg; G6 (n=10): PIA + Zea mays 1000 mg/kg, and G7 (n=10): PIA + methotrexate 0.1 mg/kg + Zea mays 1000 mg/kg. Treatments were administered by orogastric cannula daily for 21 days; pristane was administered subdermal only on day 1. Volume of hind leg was recorded with a digital plethysmometer. The radiological analysis of the legs was evaluated according to the modified Clark criteria. Results. The percentage of inflammation at the end of the experiment was: (G1) 1.50 ± 0.5; (G2) 13.73 ± 8.4; (G3) 14.76 ± 8.8; (G4) 14.22 ± 9.0; (G5) 10.81 ± 9.1; (G6) 5.31 ± 1.4; (G7) 6.38 ± 0.5. The radiological scores of the affected areas were: (G1) 0.6; (G2) 3.5; (G3) 0.6; (G4) 1.7; (G5) 1.9; (G6) 1.4; (G7) 1.0. Only the groups Zea mays L. 1000 mg/kg and methotrexate + Zea mays L. 1000 mg/kg showed a significantly lower inflammatory response (p<0.05) and showed significantly lower joint scores in relation to PIA. Conclusions. Zea mays L. (purple corn) reduces the inflammatory process and radiological modifications of PIA-induced arthritis in rats in a dose-dependent manner.
Assuntos
Animais , Feminino , Ratos , Artrite/prevenção & controle , Extratos Vegetais/uso terapêutico , Zea mays , Fitoterapia , Doenças Ósseas/prevenção & controle , Ratos Sprague-Dawley , Progressão da Doença , Modelos Animais de DoençasRESUMO
The transition from primary to secondary metabolism in antibiotic-producing Streptomyces correlates with expression of genes involved in stress responses. Consequently, regulatory pathways that regulate specific stress responses are potential targets to manipulate to increase antibiotic titers. In this study, genes encoding key proteins involved in regulation of the osmotic stress response in Streptomyces avermitilis, the industrial producer of avermectins, are investigated as targets. Disruption of either osaBSa, encoding a response regulator protein, or osaCSa, encoding a multidomain regulator of the alternative sigma factor SigB, led to increased production of both oligomycin, by up to 200%, and avermectin, by up to 37%. The mutations also conditionally affected morphological development; under osmotic stress, the mutants were unable to erect an aerial mycelium. In addition, we demonstrate the delivery of DNA into a streptomycete using biolistics. The data reveal that information on stress regulatory responses can be integrated in rational strain improvement to improve yields of bioactive secondary metabolites.
Assuntos
Antibacterianos/metabolismo , Osmorregulação , Streptomyces/genética , Streptomyces/metabolismo , Deleção de Genes , Redes Reguladoras de Genes , Ivermectina/análogos & derivados , Ivermectina/metabolismo , Engenharia Metabólica , Oligomicinas/metabolismo , Streptomyces/fisiologiaRESUMO
The mutant Penicillium chrysogenum strain dogR5, derived from strain AS-P-78, does not respond to glucose regulation of penicillin biosynthesis and ß-galactosidase, and is partially deficient in D-glucose phosphorilating activity. We have transformed strain dogR5 with the (hexokinase) hxk2 gene from Saccharomyces cerevisiae. Transformants recovered glucose control of penicillin biosynthesis in different degrees, and acquired a hexokinase (fructose phosphorylating) activity absent in strains AS- P-78 and dogR5. Interestingly, they also recovered glucose regulation of ß-galactosidase. On the other hand, glucokinase activity was affected in different ways in the transformants; one of which showed a lower activity than the parental dogR5, but normal glucose regulation of penicillin biosynthesis. Our results show that Penicillium chrysogenum AS-P-78 and dogR5 strains lack hexokinase, and suggest that an enzyme with glucokinase activity is involved in glucose regulation of penicillin biosynthesis and ß-galactosidase, thus signaling glucose in both primary and secondary metabolism; however, catalytic and signaling activities seem to be independent.
Assuntos
Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Hexoquinase/metabolismo , Penicilinas/biossíntese , Penicillium chrysogenum/genética , Penicillium chrysogenum/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Hexoquinase/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Transformação Genética , beta-Galactosidase/biossínteseRESUMO
The mutant Penicillium chrysogenum strain dogR5, derived from strain AS-P-78, does not respond to glucose regulation of penicillin biosynthesis and β-galactosidase, and is partially deficient in D-glucose phosphorilating activity. We have transformed strain dogR5 with the (hexokinase) hxk2 gene from Saccharomyces cerevisiae. Transformants recovered glucose control of penicillin biosynthesis in different degrees, and acquired a hexokinase (fructose phosphorylating) activity absent in strains AS- P-78 and dogR5. Interestingly, they also recovered glucose regulation of β-galactosidase. On the other hand, glucokinase activity was affected in different ways in the transformants; one of which showed a lower activity than the parental dogR5, but normal glucose regulation of penicillin biosynthesis. Our results show that Penicillium chrysogenum AS-P-78 and dogR5 strains lack hexokinase, and suggest that an enzyme with glucokinase activity is involved in glucose regulation of penicillin biosynthesis and β-galactosidase, thus signaling glucose in both primary and secondary metabolism; however, catalytic and signaling activities seem to be independent.
Assuntos
Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Hexoquinase/metabolismo , Penicilinas/biossíntese , Penicillium chrysogenum/genética , Penicillium chrysogenum/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Hexoquinase/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Transformação Genética , beta-Galactosidase/biossínteseRESUMO
The mutant Penicillium chrysogenum strain dogR5, derived from strain AS-P-78, does not respond to glucose regulation of penicillin biosynthesis and β-galactosidase, and is partially deficient in D-glucose phosphorilating activity. We have transformed strain dogR5 with the (hexokinase) hxk2 gene from Saccharomyces cerevisiae. Transformants recovered glucose control of penicillin biosynthesis in different degrees, and acquired a hexokinase (fructose phosphorylating) activity absent in strains AS- P-78 and dogR5. Interestingly, they also recovered glucose regulation of β-galactosidase. On the other hand, glucokinase activity was affected in different ways in the transformants; one of which showed a lower activity than the parental dogR5, but normal glucose regulation of penicillin biosynthesis. Our results show that Penicillium chrysogenum AS-P-78 and dogR5 strains lack hexokinase, and suggest that an enzyme with glucokinase activity is involved in glucose regulation of penicillin biosynthesis and β-galactosidase, thus signaling glucose in both primary and secondary metabolism; however, catalytic and signaling activities seem to be independent.
Assuntos
Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Hexoquinase/metabolismo , Penicilinas/biossíntese , Penicillium chrysogenum/genética , Penicillium chrysogenum/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Hexoquinase/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Transformação Genética , beta-Galactosidase/biossínteseRESUMO
The present work was focused on finding a relationship between reactive oxygen species (ROS) and lovastatin biosynthesis (secondary metabolism) in Aspergillus terreus. In addition, an effort was made to find differences in accumulation and control of ROS in submerged (SmF) and solid-state fermentation (SSF), which could help explain higher metabolite production in the latter. sod1 expression, ROS content, and redox balance kinetics were measured during SmF and SSF. Results showed that A. terreus sod1 gene (oxidative stress defence enzyme) was intensely expressed during rapid growth phase (trophophase) of lovastatin fermentations. This high expression decreased abruptly, just before the onset of production (idiophase). However, ROS measurements detected high concentrations only in idiophase, suggesting a link between ROS and lovastatin biosynthesis. Apparently sod1 down regulation promotes the rise of ROS during idiophase. This oxidative state in idiophase was further supported by a high redox balance observed in trophophase that changed to a low value in idiophase (around six-fold lower). The patterns of ROS accumulation, sod1 expression, and redox balance behaviour were similar in SmF and SSF. However, sod1 expression and ROS concentration (ten-fold), were higher in SmF. Our results indicate a link between ROS and lovastatin biosynthesis. Also, showed differences of physiology in SSF that yield lower but more steady ROS concentrations, which could be associated to higher lovastatin production.
Assuntos
Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Técnicas de Cultura Celular por Lotes/métodos , Proteínas Fúngicas/metabolismo , Lovastatina/biossíntese , Espécies Reativas de Oxigênio/metabolismo , Aspergillus/enzimologia , Aspergillus/genética , Técnicas de Cultura , Fermentação , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão GênicaRESUMO
Ribosome-inactivating proteins (RIPs) are toxic due to their N-glycosidase activity catalyzing depurination at the universally conserved α-sarcin loop of the 60S ribosomal subunit. In addition, RIPs have been shown to also have other enzymatic activities, including polynucleotide:adenosine glycosidase activity. RIPs are mainly produced by different plant species, but are additionally found in a number of bacteria, fungi, algae and some mammalian tissues. This review describes the occurrence of RIPs, with special emphasis on bacterial RIPs, including the Shiga toxin and RIP in Streptomyces coelicolor recently identified in S. coelicolor. The properties of RIPs, such as enzymatic activity and targeting specificity, and how their unique biological activity could be potentially turned into medical or agricultural tools to combat tumors, viruses and fungi, are highlighted.
Assuntos
Proteínas de Bactérias/toxicidade , Proteínas de Bactérias/uso terapêutico , Proteínas Inativadoras de Ribossomos/toxicidade , Proteínas Inativadoras de Ribossomos/uso terapêutico , Proteínas de Algas/toxicidade , Proteínas Fúngicas/toxicidade , Humanos , Proteínas de Plantas/toxicidade , Shigella/metabolismo , Streptomyces coelicolor/metabolismoRESUMO
Ribosome-inactivating proteins (RIPs) are cytotoxic N-glycosidases identified in numerous plants, but also constitute a subunit of the bacterial Shiga toxin. Classification of plant RIPs is based on the absence (type I) or presence (type II) of an additional lectin module. In Shiga toxin, sugar binding is mediated by a distinct RIP-associated homopentamer. In the genome of two actinomycetes, we identified RIP-like proteins that resemble plant type I RIPs rather than the RIP subunit (StxA) of Shiga toxin. Some representatives of ß- and γ-proteobacteria also contain genes encoding RIP-like proteins, but these are homologous to StxA. Here, we describe the isolation and initial characterization of the RIP-like gene product SCO7092 (RIPsc) from the Gram-positive soil bacterium Streptomyces coelicolor. The ripsc gene was expressed in Escherichia coli as a recombinant protein of about 30 kDa, and displayed the characteristic N-glycosidase activity causing specific rRNA depurination. In Streptomyces lividans and E. coli, RIPsc overproduction resulted in a dramatic decrease in the growth rate. In addition, intracellular production was deleterious for Saccharomyces cerevisiae. However, when applied externally to microbial cells, purified RIPsc did not display antibacterial or antifungal activity, suggesting that it cannot enter these cells. In a cell-free system, however, purified S. coelicolor RIPsc protein displayed strong inhibitory activity towards protein translation.
Assuntos
Proteínas de Bactérias/metabolismo , Proteínas Inativadoras de Ribossomos/metabolismo , Streptomyces coelicolor/genética , Animais , Proteínas de Bactérias/genética , DNA Bacteriano/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Genoma Bacteriano , Glicosídeo Hidrolases/metabolismo , Biossíntese de Proteínas , Coelhos , Reticulócitos/metabolismo , Proteínas Inativadoras de Ribossomos/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Streptomyces coelicolor/crescimento & desenvolvimento , Streptomyces coelicolor/metabolismo , Streptomyces lividans/genética , Streptomyces lividans/metabolismoRESUMO
Objetivo. Evaluar los resultados en trasplante hepático en el Hospital de Especialidades 71, Centro Médico Nacional Torreón, del Instituto Mexicano del Seguro Social, así como la detección de sus problemas y potenciales soluciones. Antecedentes. En 1985 se realizó el primer trasplante hepático en México y desde entonces se han trasplantado alrededor de 50 pacientes. Los resultados en estos pacientes no se han igualado todavía a los publicados a nivel mundial y probablemente una de las principales causas sea que carecemos de una organización nacional para la donación-procuración que pueda sostener a un programa de esta naturaleza. Material y métodos. Se revisaron los expedientes clínicos de los pacientes a quienes se practicó trasplante de hígado en nuestra institución en el periodo comprendido de noviembre de 1995 a noviembre de 1996. El estudio es de tipo retrospectivo, descriptivo y observacional. Se analizan las siguientes variables: Sexo, edad, etiología de la hepatopatía, tipo de trasplante, complicaciones, función del injerto, sobrevida y causas de muerte. Resultados. Se trasplantaron un total de 5 pacientes (3 masculinos y 2 femeninos), con edades de 7 a 65 años. La cirrosis fue la causa principal de la hepatopatía. Se realizaron 2 trasplantes cadavéricos y 3 segmentarios de donador vivo relacionado. Cuatro de los pacientes sobrevivieron un mínimo de 30 días y no se presentaron complicaciones arteriales ni venosas. Sólo hubo fístula biliar que se corrigió con cirugía. En los dos pacientes que presentaron disfunción del injerto no fue posible retrasplantarlos por carecer de donadores cadavéricos. Nueve meses es el mayor periodo de sobrevida. Conclusiones. 1. Es pobre la experiencia que se tiene aún en México y los resultados todavía no son similares a los publicados a nivel mundial. 2. Es indispensable la formación de una organización nacional de donación-procuración para alcanzar, con mayor frecuencia, este tipo de trasplantes
Assuntos
Humanos , Masculino , Feminino , Avaliação de Programas e Projetos de Saúde , Previdência Social , Sobreviventes , Transplante de Fígado , MéxicoRESUMO
Demostrar que la inserción de endoprótesis biliar es un procedimiento efectivo y seguro en pacientes con coledocolitiasis de extracción difícil. Antecedentes: La coledocolitiasis inicialmente era manejada quirúrgicamente, pero con alta morbimortalidad pacientes ancianos y con enfermedades sistémicas, que fueron disminuidas con el uso de la esfinterotomía endoscópica. Posteriormente aparece el cálculo biliar de difícil extracción, basado tanto en el diámetro, número, características de la porción distal del colédoco y divertículo periampular. Las alternativas terapéuticas incluyen solventes orales y locales, litotripsia mecánica, electrohidráulica intracorpórea con ondas de choque o láser. La colocación de endoprótesis biliar como tratamiento alternativo, es sencilla, accesible, efectiva y segura. Pacientes, métodos y resultados: Se estudiaron 40 pacientes con litiasis biliar de difícil extracción manejados con endoprótesis biliar, con los siguientes resultados: Cuatro pacientes no acudieron a su control. De los 36 restantes, 29 mujeres y 7 hombres (edad media de 67 años), cuatro se intervinieron quirúrgicamente por: hemorragia postesfinterotomía (1 paciente), migración de la endoprótesis (1 paciente), divertículo periampular (2 pacientes). Siete pacientes con edad media de 81 años presentaron ictericia recurrente, que fue manejada mediante reemplazo de la endoprótesis; en ellos se intercambiaron un total de 24 endoprótesis en cuatro años de vigilancia y en seis de estos pacientes utilizamos ácido ursodeoxicólico por vía oral y después de un periodo de seguimiento de 24 meses, los litos desaparecieron. En 13 pacientes la endoprótesis se colocó temporalmente, ya que en un segundo intento se extrajeron los litos de colédoco mediante litotripsia mecánica, con catéter de balón y/o canasta de Dormia. Los restantes 12 pacientes se mantienen en control, asintomáticos después de 24 meses de seguimiento. Conclusiones: Al tomar como base nuestros hallazgos, concluimos que la colocación endoscópica de una endoprótesis biliar es un procedimiento efectivo y seguro en pacientes con coledocolitiasis de difícil manejo
Assuntos
Idoso , Humanos , Masculino , Feminino , Bioprótese , Ácido Quenodesoxicólico , Colelitíase/terapia , Endoscopia , Litotripsia/instrumentaçãoRESUMO
El carcinoma de ámpula de Vater(CAV) es un tumor de presentación poco frecuente en nuestro medio, y cuando se diagnostica, por lo general, es en etapas tardías con tumor no resecable. El Diagnóstico precoz permite un manejo temprano y un mejor pronóstico. La colangio-pancreatografía endoscópica (CPE) ha demostrado ser una de las modalidades diagnósticas de mayor precisión y permite, además, realizar procedimientos terapéuticos, como la esfinterotomía endoscópica (EE) y la colocación de endoprótesis. Pacientes y Métodos: De enero de 1990 hasta diciembre de 1993 se diagnosticaron 20 pacientes con CAV, 12 hombres y 8 mujeres con edad media de 71 años (rango: 43-92), quienes ingresaron al hospital por ictericia obstructiva. Resultados: En 18 de ellos (90 por ciento) se logró un drenaje endoscópico mediante la colocación de endoprótesis biliar tipo Amsterdam de 9 cm de longitud y 10 Fr de diámetro, lo cual permitió la resolución completa de la ictericia. En 8 pacientes de los 18 se practicó EE. Dos pacientes presentaron colangitis por obstrucción de la endoprótesis, la cual se resolvió al efectuar recambio de la misma. En los 2 pacientes restantes no pudo realizarse CPE ni procedimiento de drenaje debido a infiltración tumoral que impidió la canulación. Cinco pacientes fueron sometidos a operación de Whipple, sin mortalidad operatoria. Dos de ellos fallecieron debido a la enfermedad metastásica, con sobrevida media de 16 meses. Los 3 restantes viven después de 46, 25 y 18 meses de la cirugía. La sobrevida media de los 15 pacientes restantes fue de 4 meses (rango: 1-18). Conclusiones: La esfinterotomía endoscópica o la inserción de endoprótesis biliares es un procedimiento paliativo adecuado para drenar la vía biliar en pacientes con CAV. Su utilidad como tratamiento definitivo deberá reservarse a pacientes con enfermedad metastásica o que no reúnan los criterios necesarios