RESUMEN

How organisms adapt to unfavorable environmental conditions by means of plasticity or selection of favorable genetic variants is a central issue in evolutionary biology. In the Maipo River basin, the fish Basilichthys microlepidotus inhabits polluted and non-polluted areas. Previous studies have suggested that directional selection drives genomic divergence between these areas in 4% of Amplified Fragment Length Polymorphism (AFLP) loci, but the underlying genes and functions remain unknown. We hypothesized that B. microlepidotus in this basin has plastic and/or genetic responses to these conditions. Using RNA-Seq, we identified differentially expressed genes in individuals from two polluted sites compared with fish inhabiting non-polluted sites. In one polluted site, the main upregulated genes were related to cellular proliferation as well as suppression and progression of tumors, while biological processes and molecular functions involved in apoptotic processes were overrepresented in the upregulated genes of the second polluted site. The ornithine decarboxylase gene (related to tumor promotion and progression), which was overexpressed in both polluted sites, was sequenced, and a parallel pattern of a heterozygote deficiency and increase of the same homozygote genotype in both polluted sites compared with fish inhabiting the non-polluted sites was detected. These results suggest the occurrence of both a plastic response in gene expression and an interplay between phenotypic change and genotypic selection in the face of anthropogenic pollution.

Asunto(s)

Proteínas de Peces/genética , Peces/genética , Regulación de la Expresión Génica/efectos de los fármacos , Marcadores Genéticos , Ornitina Descarboxilasa/genética , Selección Genética , Contaminantes Químicos del Agua/toxicidad , Animales , Evolución Biológica , Contaminación Ambiental/efectos adversos , Genotipo , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Polimorfismo Genético

RESUMEN

Flavobacterium psychrophilum causes rainbow trout fry syndrome (RTFS) and cold water disease (CWD) in salmonid aquaculture. We report characterization of F. psychrophilum strains and their bacteriophages isolated in Chilean salmonid aquaculture. Results suggest that under laboratory conditions phages can decrease mortality of salmonids from infection by their F. psychrophilum host strain. Twelve F. psychrophilum isolates were characterized, with DNA restriction patterns showing low diversity between strains despite their being obtained from different salmonid production sites and from different tissues. We isolated 15 bacteriophages able to infect some of the F. psychrophilum isolates and characterized six of them in detail. DNA genome sizes were close to 50 Kbp and corresponded to the Siphoviridae and Podoviridae families. One isolate, 6H, probably contains lipids as an essential virion component, based on its chloroform sensitivity and low buoyant density in CsCl. Each phage isolate rarely infected F. psychrophilum strains other than the strain used for its enrichment and isolation. Some bacteriophages could decrease mortality from intraperitoneal injection of its host strain when added together with the bacteria in a ratio of 10 plaque-forming units per colony-forming unit. While we recognize the artificial laboratory conditions used for these protection assays, this work is the first to demonstrate that phages might be able protect salmonids from RTFS or CWD.

Asunto(s)

Bacteriófagos/genética , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/prevención & control , Infecciones por Flavobacteriaceae/veterinaria , Flavobacterium/virología , Salmonidae , Animales , Bacteriófagos/clasificación , Enfermedades de los Peces/mortalidad , Enfermedades de los Peces/virología , Infecciones por Flavobacteriaceae/mortalidad , Infecciones por Flavobacteriaceae/prevención & control , Flavobacterium/patogenicidad , Variación Genética , Genoma Bacteriano , Filogenia

RESUMEN

Dominant bacterial microbiota of the gut of juvenile farmed Atlantic salmon was investigated using a combination of molecular approaches. Bacterial community composition from the stomach, the pyloric caeca, and the intestine was assessed by extracting DNA directly from each gut compartment. Temporal temperature gradient gel electrophoresis (TTGE) analysis of 16S ribosomal DNA (rDNA) amplicons showed very similar bacterial compositions throughout the digestive tract. Band sequencing revealed a narrow diversity of species with a dominance of Pseudomonas in the three compartments. However, cloning revealed more diversity among the Pseudomonas sequences. To confirm these results, we analyzed the bacterial community by amplifying the variable 16S-23S rDNA intergenic spacer region (ITS). Similar ITS profiles were observed among gastrointestinal compartments of salmon, confirming the TTGE results. Moreover, the dominant ITS band at 650 bp, identified as Pseudomonas, was observed in the ITS profile from fish collected in two seasons (July 2003 and 2004). In contrast, aerobic culture analysis revealed Shewanella spp. as the most prevalent isolate. This discrepancy was resolved by evaluating 16S rDNA and ITS polymerase chain reaction amplification efficiency from both Shewanella and Pseudomonas isolates. Very similar efficiencies were observed in the two bacteria. Hence, this discrepancy may be explained by preferential cultivation of Shewanella spp. under the experimental conditions. Also, we included analyses of pelleted feed and the water influent to explore environmental influences on the bacterial composition of the gut microbiota. Overall, these results indicate a homogeneous composition of the bacterial community composition along the gastrointestinal tract of reared juvenile salmon. This community is mainly composed of Pseudomonas spp., which could be derived from water influent and may be selectively associated with salmon in this hatchery.

Asunto(s)

Tracto Gastrointestinal/microbiología , Pseudomonas/genética , Salmo salar/microbiología , Shewanella/genética , Animales , Recuento de Colonia Microbiana , ADN Bacteriano/genética , ADN Intergénico/genética , Ecosistema , Polimorfismo de Longitud del Fragmento de Restricción , Pseudomonas/clasificación , Pseudomonas/aislamiento & purificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Shewanella/clasificación , Shewanella/aislamiento & purificación

RESUMEN

To explore the bacterial microbiota in Chilean oyster (Tiostrea chilensis), a molecular approach that permits detection of different bacteria, independently of their capacity to grow in culture media, was used. Bacterial diversity was assessed by analysis of both the 16S rDNA and the 16S-23S intergenic region, obtained by PCR amplifications of DNA extracted from depurated oysters. RFLP of the PCR amplified 16S rDNA showed a prevailing pattern in most of the individuals analyzed, indicating that a few bacterial species were relatively abundant and common in oysters. Cloning and sequencing of the 16S rDNA with the prevailing RFLP pattern indicated that this rRNA was most closely related to Arcobacter spp. However, analysis by the size of the amplified 16S-23S rRNA intergenic regions revealed not Arcobacter spp. but Staphylococcus spp. related bacteria as a major and common component in oyster. These different results may be caused by the absence of target for one of the primers employed for amplification of the intergenic region. Neither of the two bacteria species found in large abundance was recovered after culturing under aerobic, anaerobic, or microaerophilic conditions. This result, however, is expected because the number of bacteria recovered after cultivation was less than 0.01% of the total. All together, these observations suggest that Arcobacter-related strains are probably abundant and common in the Chilean oyster bacterial microbiota.

Asunto(s)

Arcobacter/genética , Ostreidae/microbiología , ARN Ribosómico 16S/genética , Animales , Arcobacter/fisiología , Clasificación , ADN Bacteriano/análisis , ADN Bacteriano/genética , Reacción en Cadena de la Polimerasa , Dinámica Poblacional , ARN Ribosómico 16S/análisis

Asunto(s)

Humanos , Masculino , Adulto , Duodeno , Estómago , Esófago , Tuberculosis

RESUMEN

Se estudiaron 104 pacientes ambulatorios con SDF no ulceroso, en fase sintomática, randomizados en dos grupos homogéneos:medicamento (48), placebo (56). El presente ensayo evalúa la eficacia de la asociación farmacológica de metoclopramida (5mg), diazepam (2.5mg)y dimeticona (100 mg) frente al placebo en el SDF de tipo no ulceroso, así como la tolerancia y efectos colaterales de la asociación. Luego de una apreciación inicial se realizó el seguimiento de ambos grupos durante 21 días, evaluándose:naúsea, llenura postprandial, ardor epigástrico, dolor vago, eructación, y balonamiento, y la impresión final del médico y del paciente. Todos los parámetros evaluados fueron ampliamente favorables para la asociación medicamentosa, siendo la diferencia estadísticamente significativa en el caso náusea, llenura postprandial y ardor epigástrico. La tolerancia en ambos grupos fue buena y como efectos colaterales adversos sólo cabe consignar una mayor somnolencia en el grupo medicamento, que fue mínima.

Asunto(s)

Humanos , Masculino , Femenino , Dispepsia , Metoclopramida , Diazepam , Simeticona

Asunto(s)

Humanos , Neoplasias Gástricas/epidemiología , Neoplasias Gástricas/prevención & control , Gastritis Atrófica , Neoplasias Intestinales

RESUMEN

We studied the evolution of HIV-1 infection and immune response during six years in two twins born from an infected mother. The children had a continuous progression of the infection, proved by CD4+ cell count, serum anti-HIV antibodies, cultivable virus and proviral load. Now, both children are on antiviral treatment. The analysis of serum antibodies showed a different immune response in both children. One of them developed higher levels of antibodies directed against viral proteins and synthetic peptides derived from their aminoacid sequence. In this child, the amount of cultivable virus increased less than in his twin. Nucleotide sequencing of a part of viral genoma, showed that the virus belonged to the B subtype, prevalent in America and Europe. The observed differences in viral sequences suggest a different selective pressure in both twins. This phenomenon could be related to the observed differences in immune response.

Asunto(s)

Síndrome de Inmunodeficiencia Adquirida/inmunología , Enfermedades en Gemelos/etiología , Anticuerpos Anti-VIH/sangre , Síndrome de Inmunodeficiencia Adquirida/sangre , Síndrome de Inmunodeficiencia Adquirida/terapia , Síndrome de Inmunodeficiencia Adquirida/transmisión , Adulto , Secuencia de Aminoácidos , Secuencia de Bases , Recuento de Linfocito CD4 , Preescolar , Enfermedades en Gemelos/genética , Femenino , Estudios de Seguimiento , Genoma Viral , Proteína gp120 de Envoltorio del VIH/fisiología , Seropositividad para VIH/inmunología , VIH-1/genética , VIH-1/aislamiento & purificación , Humanos , Transmisión Vertical de Enfermedad Infecciosa , Masculino , Datos de Secuencia Molecular , Factores de Tiempo

RESUMEN

Entre 1974 y 1992, practicamos la colonoscopía como método de diagnóstico en 2,770 pacientes de ambos sexos, con síntomas digestivos bajos, cuyas edades variaron entre 1 y 101 años, la mayoría de las cuales se distribuyeron sobre la quinta década de edad; para las 3,054 instrumentacines que se practicaron, la preparación intestinal se hizo con el método tradicional o standar en 300 procedimientos y con la administarción oral de solución salina al 9 por ciento en los otros 2,754, esta última con resultados óptimos, la dedación se consigió con la administraciónIV de diazepan 10 mg, o de Petidina 50 mg, o de midazolam 2.5 a 5 mg, y en los niños con clorhidrato de Ketamina y con la asistencia de un anestesiólogo. El alcance a ciego e ileon se obtuvo en el 95 por ciento de los casos. En 52.78 por ciento el resultado fue normal, en 45.20 por ciento normal, y en 02.02 por ciento insuficiente, principalmente debido a mal preparación intestinal. En el grupo anormal, los diagnósticos más frecuentes fuero: pólipos, cáncer, y divertículos de colon y enfermedad inflamatoria del intestino de causas específicas como TBC, proctosigmoiditis actínica, amebiasis, e inespecíficas como "colitis, proctocolitis ulcerativa inespecífica, colitis erosiva y enfermedad de Crohn. La colonoscopía es un método de diagnóstico de gran valor, sola o complementando al estudio radiográfico del colon

Asunto(s)

Humanos , Masculino , Femenino , Adolescente , Adulto , Persona de Mediana Edad , Enfermedades del Colon , Enfermedades del Colon/diagnóstico , Colonoscopía

RESUMEN

Analysis by radioimmunoprecipitation of serum samples from 27 different human immunodeficiency virus type 1 (HIV-1)-infected individuals residing in Chile showed that the sera of 26% of these individuals also react with glycoprotein gp125 of HIV type 2 (HIV-2). This cross-reaction seems to reflect a qualitative difference among infected individuals, because the titer of antibodies against gp120 of HIV-1 in the cross-reacting samples did not differ significantly from that in the non-cross-reacting samples. Most of the HIV-1-seropositive sera, including many that did not react with gp125 of HIV-2, reacted with gp140, the precursor of HIV-2 glycoproteins. The observed cross-reactions allowed us to distinguish three groups of HIV-1-infected individuals: (i) those whose sera react with both gp140 and gp125, (ii) those whose sera react with gp140, and (iii) those whose sera react with neither of these glycoproteins. The possible cause and significance of these differences is under study.

Asunto(s)

Infecciones por VIH/inmunología , VIH-1/inmunología , VIH-2/inmunología , Proteínas de los Retroviridae/inmunología , Reacciones Cruzadas , Productos del Gen env/inmunología , Glicoproteínas/inmunología , Glicoproteínas/aislamiento & purificación , Anticuerpos Anti-VIH , Humanos , Precursores de Proteínas/inmunología , Ensayo de Radioinmunoprecipitación , Proteínas de los Retroviridae/aislamiento & purificación , Productos del Gen env del Virus de la Inmunodeficiencia Humana

RESUMEN

In 1983, we isolated a porcine rotavirus (strain YM) that was prevalent in several regions of Mexico, as judged by the frequency of its characteristic electropherotype. By a focus reduction neutralization test, rotavirus YM was clearly distinguished from prototype rotavirus strains belonging to serotypes 1 (Wa), 2 (S2), 3 (SA11), 4 (ST3), 5 (OSU), and 6 (NCDV). Minor, one-way cross-neutralization (1 to 5%) was observed when antisera to the various rotavirus strains were incubated with rotavirus YM. In addition, the YM virus was not neutralized by neutralizing monoclonal antibodies with specificity to serotypes 1, 2, 3, and 5. The subgroup of the virus was determined to be I by enzyme-linked immunosorbent assay. To characterize the serotype-specific glycoprotein of the virus at the molecular level, we cloned and sequenced the gene coding for VP7. Comparison of the deduced amino acid sequence with reported homologous sequences from human and animal rotavirus strains belonging to six different serotypes further supported the distinct immunological identity of the YM VP7 protein.

Asunto(s)

Rotavirus/clasificación , Porcinos/microbiología , Secuencia de Aminoácidos , Animales , Antígenos Virales , Secuencia de Bases , Clonación Molecular , Reacciones Cruzadas , Glicoproteínas/genética , Humanos , Sueros Inmunes , Datos de Secuencia Molecular , Pruebas de Neutralización , ARN Bicatenario , ARN Viral , Rotavirus/aislamiento & purificación , Serotipificación , Proteínas Virales/genética

RESUMEN

Se efectúa un estudio sobre 20 pacientes con estenosis esofágica que originaba disfagia, 19 benignas y una por cáncer, en las que se evaluó el resultado y seguimiento de la dilatación con bujías peroral endoscópicamente guiada. Las estenosis del esófago fueron producidas más frecuentemente por cáusticos y post-quirúrgicas (65%). El 95% de los pacientes con estenosis benignas tuvieron un grado severo (menos de 11 mm de diámetro). Las estenosis por menbraba y post-quirúrgicas respondieron mejor a la dilatación; siendo las cáusticas las de más difíciles respuesta. Las dilataciones se efectuaron hasta alcanzar los 45 Fench (15 mm). El tiempo promedio de seguimiento total ha sido de 11.5 meses, y de 6.9 meses despúes de la última dilatación éxitosa. En 13 pacientes (76%) los resultados fueron considerados buenos, no requiriendo más dilataciones; en dos (12%) fueron regulares, necesitando dilataciones periódicas, y en otros dos (12%) se fracasó. Tuvimos dos complicaciones (10%), una hemorragia, que no requirió transfusiones, y una perforación; falleciendo este último dos meses despús de la intervención quirúrgica debido a complicaciones de ella. La tasa de mortalidad fue de 5%. La tasa de complicaciones relacionadas al número de sesiones de dilataciones (258), fue de 0.7%, y la de mortalidad de 0.4%. El paciente con cáncer avanzado de esófago respondió bien a sesiones de dilatación cada 15 días, tolerando la vía oral hasta poco antes de su muerte. Se considera a las dilataciones con bujías como un procedimiento adecuado en las estenosis del esófago y de fácil realización

Asunto(s)

Humanos , Niño , Adolescente , Adulto , Persona de Mediana Edad , Masculino , Femenino , Estenosis Esofágica/complicaciones , Estenosis Esofágica/terapia

RESUMEN

En el presente estudio multicéntrico abierto, se evaluó la eficacia del antagonista H2 FAMOTIDINA MSD en promover la cicatrización de la úlcera péptica gástrica, así como su tolerancia y seguridad. Veintiocho pacientes con úlcera péptica gástrica, demostrada por endoscopía e histología, recibieron famotidina 40 mg (una tableta) noche, hasta por ocho semanas. El tratamiento se suspendió a la cuarta semana en caso de evidenciarse cicatrización. Todos los pacientes fueron evaluables para eficacia y seguridad. Se consiguió cicatrización de la úlcera en veintidos de ellos (78.6%), requiriéndose sólo cuatro semanas de tratamiento en quince (53.6%). El 25% de los pacientes se tornó asintomático a las 72 horas y el 60% al finalizar la primera semana. La droga fue bien tolerada y no se registraron reacciones adversas clínicas, ni de laboratorio. Los resultados del presente estudio utilizando famotidina 40 mg. noche, muestran que esta es una terapia eficaz, bien tolerada y segura en la mayoría de pacientes con úlcera péptica gástrica

Asunto(s)

Humanos , Adulto , Persona de Mediana Edad , Masculino , Femenino , Úlcera Gástrica/terapia , Úlcera Péptica/terapia , Antagonistas de los Receptores Histamínicos/uso terapéutico , Antagonistas de los Receptores H2 de la Histamina

RESUMEN

The oxidation of ferrous iron and elemental sulfur by Thiobacillus ferrooxidans that was absorbed and unabsorbed onto the surface of sulfur prills was studied. Unadsorbed sulfur-grown cells oxidized ferrous iron at a rate that was 3 to 7 times slower than that of ferrous iron-grown cells, but sulfur-grown cells were able to reach the oxidation rate of the ferrous iron-adapted cells after only 1.5 generations in a medium containing ferrous iron. Bacteria that were adsorbed to sulfur prills oxidized ferrous iron at a rate similar to that of unadsorbed sulfur-grown bacteria. They also showed the enhancement of ferrous iron oxidation activity in the presence of ferrous iron, even though sulfur continued to be available to the bacteria in this case. An increase in the level of rusticyanin together with the enhancement of the ferrous iron oxidation rate were observed in both sulfur-adsorbed and unadsorbed cells. On the other hand, sulfur oxidation by the adsorbed bacteria was not affected by the presence of ferrous iron in the medium. When bacteria that were adsorbed to sulfur prills were grown at a higher pH (ca. 2.5) in the presence of ferrous iron, they rapidly lost both ferrous iron and sulfur oxidation capacities and became inactive, apparently because of the deposition of a jarosite-like precipitate onto the surface to which they were attached.

RESUMEN

The growth of Thiobacillus ferrooxidans in a copper-containing ore suspension incubated in shake flasks was studied by determining the number of colony-forming units both in solution and attached to ore particles. The amounts of iron and copper released from the ore under experimental conditions were also determined. The total ferrous iron either released from the minerals or generated by reduction of the ferric iron in the minerals could account for the observed growth of bacteria in solution. Only a small fraction of the total colony-forming units-about 500 per mg ore-was found to be associated with the ore particles throughout the experiments. However, the rapid development of these colonies when ore particles were plated suggested that they were produced by a number of bacteria associated with each ore particle. Accordingly, when the amount of bacteria attached to ore particles was determined by monitoring the formation of ferric iron in the plates, the percentage of the total activity associated with attached bacteria was found to be between 1 and 10%.

RESUMEN

Growth kinetics of Thiobacillus ferrooxidans in batch cultures, containing prills of elementary sulfur as the sole energy source, were studied by measuring the incorporation of radioactive phosphorus in free and adsorbed bacteria. The data obtained indicate an initial exponential growth of the attached bacteria until saturation of the susceptible surface was reached, followed by a linear release of free bacteria due to successive replication of a constant number of adsorbed bacteria. These adsorbed bacteria could continue replication provided the colonized prills were transferred to fresh medium each time the stationary phase was reached. The bacteria released from the prills were unable to multiply, and in the medium employed they lost viability with a half-life of 3.5 days. The spreading of the progeny on the surface was followed by staining the bacteria on the prills with crystal violet; this spreading was not uniform but seemed to proceed through distortions present in the surface. The specific growth rate of T. ferrooxidans ATCC 19859 was about 0.5 day, both before and after saturation of the sulfur surface. The growth of adsorbed and free bacteria in medium containing both ferrous iron and elementary sulfur indicated that T. ferrooxidans can simultaneously utilize both energy sources.

Asunto(s)

ARN Mensajero/genética , ARN Viral/genética , Rotavirus/genética , Proteínas Virales/genética , Animales , Bovinos , Células Cultivadas , Péptidos/genética , Biosíntesis de Proteínas , ARN Bicatenario/genética

RESUMEN

Rotavirus was investigated in the feces of 232 children under five years of age with acute infectious gastroenteritis by means of viral RNA electrophoretic technique. 15.1 per cent of cases were positive and no predominance was observed regarding age or seasonal period. Approximately 50 per cent corresponded to one of the two rotavirus types, byt type 2 (2 L) was predominant in the first six months of the year and type 1 (2 S) in the other six. Results are consistent with those obtained by other authors for it is considered that approximately 20 per cent of acute diarrheas during infancy are caused by viral agents.

Asunto(s)

Gastroenteritis/etiología , ARN Viral/análisis , Infecciones por Reoviridae , Reoviridae , Rotavirus , Enfermedad Aguda , Factores de Edad , Preescolar , Electroforesis en Gel de Agar , Electroforesis en Gel de Poliacrilamida , Heces/microbiología , Gastroenteritis/microbiología , Humanos , Lactante , Recién Nacido , Reoviridae/aislamiento & purificación , Rotavirus/aislamiento & purificación

RESUMEN

Se estudio la presencia de rotavirus en la materia fecal de 232 ninos menores de cinco anos con gastroenteritis infecciosa aguda por medio de la tecnica de electroforesis del RNA viral. Se encontraron 15.1 por ciento de casos positivos, no observandose predominio en relacion con la edad o la epoca del ano.Aproximadamente 50 por ciento correspondieron a cada uno de los dos tipos de rotavirus, pero el tipo 2 (2 L) predomino en los seis primeros meses del ano y el tipo 1 (2 S) en los otros seis. Los resultados concuerdan con los obtenidos por otros autores, ya que se considera que aproximadamente 20 por ciento de las diarreas agudas de la infancia son causadas por estos agentes virales

Asunto(s)

Gastroenteritis , Rotavirus , Heces

RESUMEN

During the period October to December 1979, rotaviruses were obtained from infants and young children hospitalized with acute gastroenteritis in Mexico City and were compared by analysis of the migration of their double-stranded ribonucleic acid (RNA) genome segments in gel electrophoresis. Comparison of the results of this analysis and of those of similar studies carried out in 1977 and 1978 showed that the two rotavirus electropherotypes designated 2s and 21 have been continuously present and that the proportion in which these two types have been found in hospitalized patients has varied greatly year to year. The RNAs from rotaviruses 2s and 21 differed in the electrophoretic migraton of at least eight genome segments. However, RNAs from virus assigned to the same electrophoreotypes were not necessarily identical: on the basis of small but significant differences in the migration of segment 7, 8, or 9, isolates of types 2s and 21 could be assigned to two and three different subtypes, respectively. Human rotaviruses obtained in a distant geographical region, Santiago, Chile, in July 1979 had RNA electrophoretic patterns similar to that of electropherotype 21 but different from it in the migration of one or two of the larger RNA segments.

Asunto(s)

ARN Viral/análisis , Reoviridae/análisis , Rotavirus/análisis , Preescolar , Chile , Electroforesis en Gel de Poliacrilamida , Humanos , Lactante , Recién Nacido , México