RESUMEN
This study presents a list of parasitic fish nematodes from the Brazilian Amazon based on the previous Brazilian list including scientific assessments carried out between 2010 and 2021. A total of 16 families, 48 species and 28 undetermined species of nematodes associated with fish are included in the checklist, in addition to 93 host species and 15 geographical records.
Asunto(s)
Enfermedades de los Peces , Nematodos , Animales , Brasil , Lista de Verificación , Enfermedades de los Peces/epidemiología , Peces , Especificidad del Huésped , HumanosRESUMEN
The aerobic bacteria microflora of the upper small bowel in normal children and in children with acute diarrhea was studied. Forty one children aging between 2 months and 5 years were divided in 3 groups: Group I--13 wellnourished children with no signs of gastrointestinal abnormalities remained intubated for less than 4 hours; Group II--11 wellnourished children that remained intubated for a period of time varying from 4 to 24 hours; Group III--17 children with acute diarrhea. There was a striking difference in the bacterial pattern between children from groups I and II and these findings were attributed to the prolonged time of intubation. In group I the jejunal fluid was sterile in approximately 40% of the children and in the others there was only growth of a GRAM positive flora while in group II the jejunal fluid never presented as a sterile one, and in approximately 73% of the cases there was a growth of a mixed GRAM positive and GRAM negative microflora, mainly due to Enterobacteria. In group III an aerobic microflora different from that one verified in group I was found in 76,4% of the patients. In 47.05% of the cases a bacterial growth equivalent to the fecal flora has been observed, in 5.89% Pseudomonas aeruginosa was located and in 23.52% yeasts were cultured from the jejunal fluid. These data confirm the hypothesis that bacterial and fungi infections are most prevalent in underdeveloped countries. This is probably due to the poor sanitary conditions observed in these countries associated with a high index of environmental contamination.
Asunto(s)
Bacterias/crecimiento & desarrollo , Diarrea Infantil/fisiopatología , Intubación Gastrointestinal , Yeyuno/microbiología , Enfermedad Aguda , Bacterias/aislamiento & purificación , Preescolar , Femenino , Fluoroscopía , Humanos , Lactante , MasculinoRESUMEN
E. coli can induced diarrhea either by enterotoxin production or by invasion of the colonic mucosa. Here we report a 2/12 year old infant with caute diarrhea induced by E. coli strain, isolated from the jejunal fluid, that had no enterotoxigenic activity but invaded the small intestinal mucosa and induced severe morphological alterations. Total villous atrophy and monosaccharide intolerance occured. After 51 days of hospitalization there was a partial recovery of the small intestinal morphology and the patient could also tolerate disaccharides again.
Asunto(s)
Diarrea Infantil/etiología , Infecciones por Escherichia coli/complicaciones , Mucosa Intestinal/microbiología , Monosacáridos/metabolismo , Enfermedad Aguda , Preescolar , Humanos , Yeyuno/patología , MasculinoAsunto(s)
Antígenos/genética , Animales , Formación de Anticuerpos , Antígenos/inmunología , Antígenos Bacterianos , Bovinos , Columbidae , Cruzamientos Genéticos , Eritrocitos/inmunología , Femenino , Ligamiento Genético , Inmunoglobulina G/inmunología , Inmunoglobulina M/inmunología , Cinética , Linfocitos/inmunología , Macrófagos/inmunología , Masculino , Ratones , Ovalbúmina/inmunología , Salmonella/inmunología , Albúmina Sérica Bovina/inmunología , Ovinos , gammaglobulinas/inmunologíaRESUMEN
Eighteen of 1,200 colonies of Escherichia coli isolated from "keebe," hamburger, or sausage produced heat-labile enterotoxin. None of them produced heat-stable enterotoxin. The characteristics of 9 of the 18 strains are presented.
Asunto(s)
Enterotoxinas/biosíntesis , Escherichia coli/aislamiento & purificación , Microbiología de Alimentos , Productos de la Carne , Carne , Antibacterianos/farmacología , Escherichia coli/clasificación , Escherichia coli/metabolismo , Calor , SerotipificaciónRESUMEN
A new invasive Escherichia coli serogroup is described. Its O antigen is identical to the O antigen of Shigella boydii 3. We propose the designation of E. coli São Paulo for this serogroup until the situation of its O antigen is settled.
Asunto(s)
Diarrea Infantil/microbiología , Infecciones por Escherichia coli/microbiología , Escherichia coli/patogenicidad , Antígenos Bacterianos/análisis , Escherichia coli/clasificación , Escherichia coli/inmunología , Humanos , Lactante , Serotipificación , Terminología como AsuntoRESUMEN
Enterotoxigenic Escherichia coli strains were isolated from 32 (13.4%) of 245 children with diarrhea and from 11 (11.4%) of 96 children of the control group. Strains producing heat-labile toxin were found more frequently in normal children than in children with diarrhea. Strains producing heat-stable toxin and both heat-labile and heat-stable toxins were isolated only from children with diarrhea. Association of these strains with diarrhea was highly significant as shown by statistical analysis. The O:H types and the colonization factors of strains producing heat-stable toxin and both heat-labile and heat-stable toxins are presented.
Asunto(s)
Toxinas Bacterianas , Diarrea/microbiología , Enterotoxinas/biosíntesis , Proteínas de Escherichia coli , Escherichia coli/aislamiento & purificación , Heces/microbiología , Brasil , Niño , Preescolar , Escherichia coli/metabolismo , Humanos , LactanteRESUMEN
C57BL/6 mice transgenic for a mu heavy chain gene, the VDJ region of which came from the BALB/c hybridoma 17.2.25, expressed high levels of antibody carrying determinants specific for the transgene (idiotypes). The individual antibodies made by hybridomas from transgenic mice, however, were generally encoded by endogenous genes; in most cases the transgene was present but not expressed. The endogenous, idiotype-positive antibodies had heavy chains that were notable for the high frequencies of JH4 (as in the transgene) and VH segments from the VH81X family (unrelated to the transgene). The expression of endogenous genes mimicking the idiotype of the transgene suggests that a rearranged gene introduced into the germ line can activate powerful cellular regulatory influences.
Asunto(s)
Regulación de la Expresión Génica , Cadenas Pesadas de Inmunoglobulina/genética , Cadenas mu de Inmunoglobulina/genética , Ratones Endogámicos BALB C/genética , Ratones Endogámicos C57BL/genética , Animales , Anticuerpos Monoclonales/inmunología , ADN/genética , Femenino , Hibridomas/inmunología , Cadenas Pesadas de Inmunoglobulina/biosíntesis , Idiotipos de Inmunoglobulinas/genética , Cadenas mu de Inmunoglobulina/biosíntesis , Masculino , Ratones , Ratones Endogámicos BALB C/inmunología , Ratones Endogámicos C57BL/inmunología , Microinyecciones , Datos de Secuencia Molecular , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/genética , Transformación GenéticaRESUMEN
The selective breeding for antibody production against bovine serum albumin (BSA) and rabbit gamma-globulin (RGG) induced a large modification in responsiveness in the high (Hv) and low (Lv) responder lines at selection limit. The total response to selection (RT) was 9.0 log2 for BSA and 8.4 log2 for RGG. This gives an interline difference of 500-fold and 337-fold respectively in terms of passive agglutinin titres. For BSA responsiveness, there is, in F1 interline hybrids, an incomplete dominance effect of the low character (-0.41) and a marked maternal effect. Complete dominance effect of high character (1.08) without any maternal effect is observed for responses to RGG. The phenotypical variability of BSA responses in F2 segregants is due 60% to genetic factors and 40% to environmental effects. Such a distribution cannot be achieved for RGG responsiveness. Both responses to BSA and RGG are controlled by the additive effect of several independent loci (polygenic regulation). One of these genes is linked with the H-2 locus. The H-2 linked gene accounts for 29% of the total interline difference for response to BSA and only 11% for response to RGG. Experiments carried out to measure the reciprocal nonspecific effect of BSA and RGG responses failed to give clear-cut results. This important phenomenon will be the subject of the companion article.
Asunto(s)
Anticuerpos/genética , Formación de Anticuerpos , Ratones/genética , Albúmina Sérica Bovina/inmunología , gammaglobulinas/inmunología , Animales , Cruzamiento , Bovinos , Genes MHC Clase II , Antígenos H-2/genética , Ratones/inmunología , Conejos , Selección GenéticaRESUMEN
In order to measure the reciprocal nonspecific effect of the genetic regulation of antibody responsiveness to bovine serum albumin (BSA) and rabbit gamma-globulin (RGG), two independent bidirectional selective breedings for responses to these two antigens were carried out: selection V/BSA and selection V/RGG respectively. The total interline separation at selection limit (RT) was 5.3 log2 for selection V/BSA and 2.6 log2 for selection V/RGG. The sum of these two values (7.9 log2) is similar to the RT in selection V carried out by alternating these two antigens in consecutive generations. In selection V/BSA, the nonspecific effect for responsiveness to RGG was 72%. In selection V/RGG, the nonspecific effect for BSA responsiveness was 135%. The F1 hybrids between homologous lines of selection V/BSA and selection V/RGG presented a larger difference in antibody response to both antigens than their parental lines. This demonstrates an additive effect of the loci controlling the two responses.
Asunto(s)
Anticuerpos/genética , Formación de Anticuerpos , Ratones/genética , Albúmina Sérica Bovina/inmunología , gammaglobulinas/inmunología , Animales , Cruzamiento , Bovinos , Regulación de la Expresión Génica , Genes MHC Clase II , Ratones/inmunología , Conejos , Selección GenéticaRESUMEN
Nine out of 11 Escherichia coli strains belonging to enteropathogenic O128 serogroup were shown to produce heat-stable enterotoxin. This property may be related to the pathogenicity of this serogroup of bacteria.
Asunto(s)
Toxinas Bacterianas/biosíntesis , Enterotoxinas/biosíntesis , Escherichia coli/metabolismo , Diarrea Infantil/microbiología , Escherichia coli/clasificación , Calor , Humanos , Serotipificación , Especificidad de la EspecieRESUMEN
A strain of Escherichia coli isolated from a child with diarrhea was biochemically similar and antigenically identical (O and K antigens) to the standard strain of E. coli O group 29 and was positive in the Serény test for invasiveness, which suggests that it can cause a Shigella-like illness.
Asunto(s)
Diarrea/microbiología , Escherichia coli/clasificación , Carboxiliasas/biosíntesis , Preescolar , Escherichia coli/metabolismo , Heces/microbiología , Humanos , Lisina/metabolismo , SerotipificaciónRESUMEN
In a study of enterotoxigenic strains of Escherichia coli isolated from children with diarrhea in São Paulo, Brazil, a new enterotoxin and antibiotic resistance plasmid that carries heat-labile toxin, heat-stable toxin, and drug resistance genes was found. This is the first such plasmid to be found in a human strain of E. coli. The plasmid is nonconjugative, has a molecular weight of at least 54 x 10(6), and is mobilized by the R plasmid present in the host strain.
Asunto(s)
Toxinas Bacterianas , Enterotoxinas/genética , Proteínas de Escherichia coli , Escherichia coli/genética , Plásmidos , Factores R , Antibacterianos/farmacología , Colicinas/genética , Conjugación Genética , Escherichia coli/efectos de los fármacos , Humanos , Peso MolecularRESUMEN
The genetic modifications of immunocompetent cell functions were investigated in high (H) and low (L) antibody responder lines of mice obtained by selective breeding for responsiveness to flagellar and somatic antigens of Salmonellae (Selection III and Selection IV, respectively). Several lines of evidence converge to demonstrate that the differences in antibody responses between the H and L lines of the two selections are not due to the modification of antigen handling by macrophages. This contrasts with previous observations that macrophages play a major role in interline differences in Selections I and II. The choice of antibody titres after secondary challenge as the phenotypic character in Selections III and IV may explain why the regulatory role of macrophages was minimized, compared with Selections I and II which were carried out for primary responses to heterologous erythrocytes. In Selections III and IV, H mouse lymphocytes were more efficient than L mouse lymphocytes in restoring immunoresponsiveness to irradiated hosts. In contrast, allogeneic skin grafts were rejected at a similar rate in L as well as in H mice of the two Selections and in vitro lymphoproliferative responses to T cell mitogens were also equivalent in the four lines.
Asunto(s)
Anticuerpos Antibacterianos/biosíntesis , Células Productoras de Anticuerpos/inmunología , Antígenos Bacterianos/inmunología , Salmonella/inmunología , Animales , Células Presentadoras de Antígenos/inmunología , Flagelos/inmunología , Rechazo de Injerto , Inmunización Pasiva , Inmunogenética , Activación de Linfocitos , Macrófagos/inmunología , Ratones , Especificidad de la Especie , Bazo/inmunologíaRESUMEN
Resistance to Toxoplasma gondii infection was studied in the high (H/f) and low (L/f) antibody responder lines of mice that were selected on the basis of quantitative antibody responsiveness to the flagellar antigen of Salmonella (selection III). No interline difference was observed in resistance to a highly virulent strain of T. gondii. In contrast, H/f mice were much more resistant than L/f mice to a moderately virulent strain of T. gondii: a 5000-fold difference in terms of the 50% lethal dose was found. The degree of resistance in (H/f X L/f)F1 hybrids was intermediate compared with that in parental lines for both mortality and survival time. The antibody titers to Toxoplasma antigens measured during the course of the infection were significantly higher in H/f than in L/f mice. This interline difference was underestimated because parasite multiplication occurs faster in L/f mice, which increases antigenic stimulation. The stronger resistance of H/f mice is probably due to their higher capacity of antibody production in the course of infection.
Asunto(s)
Toxoplasma/inmunología , Toxoplasmosis Animal/inmunología , Animales , Formación de Anticuerpos , Antígenos de Protozoos/inmunología , Femenino , Genes MHC Clase II , Inmunidad Innata , Masculino , Ratones , Fagocitos/parasitología , Toxoplasma/patogenicidad , Toxoplasmosis Animal/genética , VirulenciaRESUMEN
T-helper function was evaluated in mice genetically selected for high (H) or low (L) antibody (Ab) responsiveness to Salmonella flagellar antigen (Ag) (Selection III). In this Selection as opposed to what was demonstrated in Selections I, II and IVA, the interline difference was not proven to be based upon the modification of Ag processing and presentation at macrophage level. CD4+/CD8+ lymph node ratio is similar in HIII and LIII mice, both lines being equally susceptible to in vivo depletion of CD4+ T cells by GK 1-5 monoclonal antibody (mAb) treatment. Nevertheless, the Ab responsiveness of the two lines was differently modulated by GK 1-5 mAb: the inhibition of Ab responses to various Ag required lower mAb doses and was long lasting in LIII as compared to the transient effect of higher mAb doses observed in HIII. LIII mice were also refractory to Salmonella-induced reversion of GK 1-5 mAb inhibition. Moreover, in vitro specific I proliferation was constantly lower in LIII, though its IL-2 production was unexpectedly similar to that of HIII T cells. Results of in vivo and in vitro experiments are thus consistent with a defective response of T-helper cells to immunogenic challenge in LIII mice.
Asunto(s)
Antígenos CD4/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Formación de Anticuerpos/inmunología , División Celular/inmunología , Femenino , Interleucina-2/biosíntesis , Ganglios Linfáticos/inmunología , Activación de Linfocitos/inmunología , Masculino , Ratones , Ratones Endogámicos , gammaglobulinas/inmunologíaRESUMEN
Escherichia coli strains belonging to serotype O128ac:H12 and producing heat-stable enterotoxin (ST) and colonization factor CFA/I were found in Sao Paulo in children with diarrhea, but not in normal children. Segregants occurred in such strains with a frequency of about 10%, which have lost the ability to produce ST and CFA/I at the same time. From one strain, both properties were transformed jointly in matings to an E. coli K-12 strain. All such ST+ CFA/I+ progeny had received two plasmids of length 97 and 64 kilobases in the matings. Insertion of a transposon, Tn5, carrying a gene for kanamycin resistance, into the two plasmids enabled us to select for kanamycin-resistant progeny in further matings. Analysis of such progeny strains in terms of plasmid content and production of ST and CFA/I revealed that the larger plasmid carries the genes for St and CFA/I and is not self-transmissible, whereas the smaller plasmid does not carry any recognizable phenotypic traits, but is conjugative and promotes cotransfer of the larger plasmid with a frequency of about 30%.
Asunto(s)
Conjugación Genética , Enterotoxinas/genética , Escherichia coli/genética , Plásmidos , Ensayo de Unidades Formadoras de Colonias , Elementos Transponibles de ADN , Escherichia coli/clasificación , Escherichia coli/fisiología , SerotipificaciónRESUMEN
The relationship among O groups, O:H serotypes and enterotoxigenic phenotypes was examined in 76 Escherichia coli strains isolated in Brazil from different sources. Of the 17 heat-labile and -stable enterotoxin (LT/ST)-producing strains whose O antigens were identified, 15 belonged to serotypes O6:H16 (7 strains), O63:H- (5 strains), and O139:H28 (3 strains). All 11 ST strains were in group OO128PAC, which was represented by four O:H serotypes. The 23 LT strains with the O antigen identified were distributed among serotypes of 14 O groups. Colonization factor CFA/I was not found in any of the LT strains, but it was found in six LT/ST and three ST strains. On the whole, each E. coli O:H serotype had a particular fermentation pattern. LT/ST as well as ST strains were all isolated from patients with diarrhea, whereas LT strains were isolated from patients with diarrhea, normal children, food, and river water.
Asunto(s)
Toxinas Bacterianas/biosíntesis , Enterotoxinas/biosíntesis , Escherichia coli/metabolismo , Metabolismo de los Hidratos de Carbono , Diarrea/microbiología , Escherichia coli/clasificación , Escherichia coli/aislamiento & purificación , Fermentación , Microbiología de Alimentos , Humanos , Serotipificación , Microbiología del AguaRESUMEN
Fifty-one strains of Escherichia coli isolated from humans, swine, food, and water and identified as enterotoxinogenic by the Y-1 adrenal cell assay, were examined for heat-labile enterotoxin (LT) production by the passive immune hemolysis test. Cholera antitoxin, anti-choleragenoid and anti-LT were used as antisera. Cholera antitoxin was much more potent than anti-choleragenoid and LT antiserum in the detection of LT-positive strains. All strains isolated from pigs and sausage were negative in tests made with LT antiserum. A few strains isolated from humans, food, and water also gave negative results. These data showed that the passive immune hemolysis test is not as efficient as the Y-1 adrenal cell assay in the detection of enterotoxinogenic E. coli strains.
Asunto(s)
Toxinas Bacterianas/biosíntesis , Enterotoxinas/biosíntesis , Escherichia coli/metabolismo , Hemólisis , Técnicas Inmunológicas , Toxinas Bacterianas/análisis , Enterotoxinas/análisisRESUMEN
Selective breedings of mice were carried out for quantitative antibody responsiveness to flagellar Ag., f (Selection III) or somatic Ag., s (Selection IV) of two non cross-reacting Salmonellae (Salm. tm., Salm. or.) alternated for immunization of consecutive generations. At the selection limit, these selections produced homozygous high (H) and low (L) responder lines for the character investigated: peak agglutinin response to optimal secondary immunization. The responsiveness to both f and s Ags. is submitted to polygenic regulation. The heritability (h2) realized during the selective breeding was 0.37 +/- 0.07 for the response to fAg. and 0.40 +/- 0.1 for the response to s Ag. The respective part of genetic and environmental variance in F2 hybrids was 64% and 36% in selection III and 61% and 39% in selection IV. In the two selections, the dominance variance is negligible (less than 1%), therefore the genetic variance is essentially additive. The additive variance calculated as the heritable fraction of the F2 hybrid variance is somewhat lower, the reason for this difference is discussed. The quantitative antibody response to f Ag. in selection III is controlled by about seven independent loci. The antibody response to s Ag. in selection IV is controlled by about four independent loci. A possible association of relevant genes with the H-2 locus was investigated. In selection III, no significant participation if H-2 linked genes, in the regulation of responses to f and s Ags. of Salm. tm and Salm. or. could be demonstrated. In selection IV a partial contribution of H-2 linked genes was observed concerning responsiveness to both f and s Ags. of Salm. tm. but not Salm. or. Ags. The H-2 effect accounts for 25% of the total interline difference.