Asunto(s)
Chryseobacterium , Infecciones por Flavobacteriaceae , Meningitis Bacterianas/microbiología , Infecciones Comunitarias Adquiridas/diagnóstico , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infecciones por Flavobacteriaceae/diagnóstico , Infecciones por Flavobacteriaceae/tratamiento farmacológico , Humanos , Lactante , Masculino , Meningitis , Meningitis Bacterianas/diagnóstico , Meningitis Bacterianas/tratamiento farmacológicoRESUMEN
Aberrant de novo methylation of DNA is considered an important mediator of tumorigenesis. To investigate the role of de novo DNA methyltransferase 3a (Dnmt3a) in intestinal tumor development, we analyzed the expression of Dnmt3a in murine colon crypts, murine colon adenomas and human colorectal cancer using RNA fluorescence in situ hybridization (FISH), quantitative PCR and immunostaining. Following conditional deletion of Dnmt3a in the colon of APC((Min/+)) mice, we analyzed tumor numbers, genotype of macroadenomas and laser dissected microadenomas, global and regional DNA methylation and gene expression. Our results showed increased Dnmt3a expression in colon adenomas of APC((Min/+)) mice and human colorectal cancer samples when compared with control tissue. Interestingly, in tumor tissue, RNA FISH analysis showed highest Dnmt3a expression in Lgr5-positive stem/progenitor cells. Deletion of Dnmt3a in APC((Min/+)) mice reduced colon tumor numbers by ~40%. Remaining adenomas and microadenomas almost exclusively contained the non-recombined Dnmt3a allele; no tumors composed of the inactivated Dnmt3a allele were detected. DNA methylation was reduced at the Oct4, Nanog, Tff2 and Cdkn1c promoters and expression of the tumor-suppressor genes Tff2 and Cdkn1c was increased. In conclusion, our results show that Dnmt3a is predominantly expressed in the stem/progenitor cell compartment of tumors and that deletion of Dnmt3a inhibits the earliest stages of intestinal tumor development.
Asunto(s)
Adenoma/genética , Neoplasias Colorrectales/genética , ADN (Citosina-5-)-Metiltransferasas/genética , Metilación de ADN/genética , Células Madre Neoplásicas/patología , Adenoma/patología , Animales , Transformación Celular Neoplásica/genética , Colon/metabolismo , Colon/patología , Neoplasias Colorrectales/patología , Inhibidor p57 de las Quinasas Dependientes de la Ciclina/biosíntesis , Inhibidor p57 de las Quinasas Dependientes de la Ciclina/genética , ADN (Citosina-5-)-Metiltransferasas/biosíntesis , ADN Metiltransferasa 3A , Regulación Neoplásica de la Expresión Génica , Proteínas de Homeodominio/genética , Humanos , Hibridación Fluorescente in Situ , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mucinas/biosíntesis , Mucinas/genética , Proteínas Musculares/biosíntesis , Proteínas Musculares/genética , Proteína Homeótica Nanog , Factor 3 de Transcripción de Unión a Octámeros/genética , Péptidos/genética , Regiones Promotoras Genéticas , Reacción en Cadena en Tiempo Real de la Polimerasa , Factor Trefoil-2RESUMEN
INTRODUCTION: Pneumococcal infections are a major public health problem because of the virulence of this bacterium and its ability to develop resistance. MATERIAL AND METHOD: Two hundred and ninety-four strains of Streptococcus pneumoniae were isolated from sterile (56.8%) and non-sterile samples (43.2%), from January 2001 to July 2010. RESULTS: The interpretation of antibiotic susceptibility testing, according to CLSI criteria (M100-S21 2011), yielded a 25.2% overall resistance to penicillin, with 23.5% of strains isolated from CSF (meningitis), and only 1.7% in other samples. Resistance to cefotaxime was 8.1% (including 4.4% at a high level). The most common serotypes were: 14 (19.5%), 23F (9.7%), 6B (9.3%), 19F (5.4%), and serotype 1 (5%). The percentage of these serotypes isolated from normally sterile sites in children under 5 years of age was 31.25% for 14, 10.4% for 23F, 8.3% for 19F, 6.25% for 6B, and 4.2% for serotype 1. The theoretical vaccinal coverage against invasive infections in children under 2 years of age was 61.5%, 69.2%, and 76.9% for the 7-valent, 10-valent, and 13-valent conjugate vaccines, respectively. Penicillin non-susceptible Streptococcus pneumoniae (PNSP) strains accounted for 67.1, 68.6, and 72.8% for each of these three vaccines. CONCLUSION: There was a variation of serotype rates compared to previous studies. The increase in pneumococcal antibiotic resistance is concerning, particularly for the treatment of pneumococcal infections in children and infants. Pneumococcal vaccination is not compulsory yet in Algeria.
RESUMEN
INTRODUCTION: Pneumococcal infections are a major public health problem because of the virulence of this bacterium and its ability to develop resistance. MATERIAL AND METHOD: Two hundred and ninety-four strains of Streptococcus pneumoniae were isolated from sterile (56.8%) and non-sterile samples (43.2%), from January 2001 to July 2010. RESULTS: The interpretation of antibiotic susceptibility testing, according to CLSI criteria (M100-S21 2011), yielded a 25.2% overall resistance to penicillin, with 23.5% of strains isolated from CSF (meningitis), and only 1.7% in other samples. Resistance to cefotaxime was 8.1% (including 4.4% at a high level). The most common serotypes were: 14 (19.5%), 23F (9.7%), 6B (9.3%), 19F (5.4%), and serotype 1 (5%). The percentage of these serotypes isolated from normally sterile sites in children under 5 years of age was 31.25% for 14, 10.4% for 23F, 8.3% for 19F, 6.25% for 6B, and 4.2% for serotype 1. The theoretical vaccinal coverage against invasive infections in children under 2 years of age was 61.5%, 69.2%, and 76.9% for the 7-valent, 10-valent, and 13-valent conjugate vaccines, respectively. Penicillin non-susceptible Streptococcus pneumoniae (PNSP) strains accounted for 67.1, 68.6, and 72.8% for each of these three vaccines. CONCLUSION: There was a variation of serotype rates compared to previous studies. The increase in pneumococcal antibiotic resistance is concerning, particularly for the treatment of pneumococcal infections in children and infants. Pneumococcal vaccination is not compulsory yet in Algeria.
Asunto(s)
Infecciones Neumocócicas/microbiología , Streptococcus pneumoniae/aislamiento & purificación , Adulto , Argelia/epidemiología , Preescolar , Países en Desarrollo , Farmacorresistencia Bacteriana Múltiple , Humanos , Lactante , Resistencia a las Penicilinas , Infecciones Neumocócicas/epidemiología , Infecciones Neumocócicas/prevención & control , Vacunas Neumococicas , Estudios Retrospectivos , Serotipificación , Streptococcus pneumoniae/clasificación , Streptococcus pneumoniae/efectos de los fármacos , Vacunación/estadística & datos numéricosRESUMEN
Electropermeabilization of Clostridium cellulolyticum was optimized using ATP leakage assays. Electrotransformation was then performed under optimized conditions (6 to 7.5 kV x cm(-1) field strength applied during 5 ms to a mixture containing methylated plasmids and late exponential phase cell suspensions (10 molecules:1 cell) in a sucrose-containing buffer). Transformants were only obtained when 7 or 7.5 kV x cm(-1) pulses were applied. Transformation efficiencies evaluated from the growth curves of transformed cells were between 10(5) and 10(7) transformants per microgram of plasmid DNA for five different replicon-based plasmids. Restriction nuclease digestion patterns of pJIR418 purified from transformed Clostridia and Escherichia coli were indistinguishable, indicating that heterologous DNA was structurally stable in the Clostridium strain. Copy numbers of 130, 70 and 10 were estimated from purification yield for pCTC1, pKNT19 and pJIR418, respectively.
Asunto(s)
Clostridium/genética , Transformación Bacteriana/genética , Permeabilidad de la Membrana Celular , Electricidad , Plásmidos , Selección GenéticaRESUMEN
We have evaluated the activity of a new fluoroquinolone, trovafloxacin (CP-99,219), against 434 strains; 24 of them are resistant to ciprofloxacin. Against gram-negative bacteria, trovafloxacin has the same activity as the others fluoroquinolones. Against gram-positive bacteria, this antibiotic agent is very active. (MIC = 0.016 to 0.5 microgram/ml); Streptococcus is the most sensitive species. The ciprofloxacin resistant strains are also resistant to trovafloxacin.