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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.

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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.

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The five selections carried out in the mouse for high or low antibody responsiveness to various multideterminant immunogens were successful. In all cases the large interline difference was shown to result from the additive effects of several independently segregating loci (polygenic regulation). However, important peculiarities were demonstrated in these original selections concerning either the cellular mechanisms operating or the effect of the selected genes on antibody responses to antigens unrelated with those used for the selection (multi-specific effect). In an attempt to improve and generalize the effect of selection, the 5 high and the 5 low lines were inter-crossed to obtain populations with a balanced proportion of the 5 genomes. These two populations were then submitted to selective breedings in which the phenotypic character was the weighted responses to pluri-antigen immunization. The data obtained in 16 consecutive generations of two selective breedings (general-primary, GP and general-secondary, GS, responses) carried out from these populations are reported. The genetic parameters of the response to GP and GS selections are compared with those obtained in the original selections. The final result of both GP and GS selections demonstrate a marked improvement of the high and low antibody production traits, both quantitatively (interline divergence) and qualitatively (multi-specific effect). The success of GP and GS selections agrees with the concept that distinct groups of genes are preferentially affected by selection according to the nature of the selection antigen and the immunization procedure.

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The high (H) and low (L) antibody responder lines of mice produced by selective breeding are characterized by different modifications in immunocompetent cell potentialities, according to the immunization procedure used for the selection process. In selections I and II, the difference in antibody responsiveness between H and L lines was clearly shown to depend mainly on macrophage function: the more rapid catabolism of antigens in L mice was the main cause of the low antibody production. In contrast, up to now, no difference has been observed between H and L mice of selections III and IV in terms of the macrophage accessory role. The administration of silica particles has a well known impairment effect on macrophage activity. Therefore, the effect of silica injection on the kinetics of antibody responses to selection antigens was compared in H and L mice of the four selections. Silica was given either intravenously or locally in one hind footpad 6 or 24 h before immunization by the same route. Silica treatment consistently improved antibody responsiveness in the L mice of selections I and II, but had no effect in the L mice of selections III and IV. The antibody responses of the H lines of the four selections were not substantially modified by silica injections. Therefore, the silica treatment reduced the interline difference in antibody responses in selections I and II only, by interfering with the expression of the genetic modification of macrophage activity. However, a similar effect was not obtained with other substances known to affect macrophages, including dextran sulphate or carrageenan. The results reported here are in agreement with the above-mentioned statement that the genetic modification of macrophage function plays a major role in the interline difference in selections I and II and is not involved in selections III and IV.

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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.

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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.

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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.

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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.

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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.

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Serum Ig concentration and isotype distribution were determined in the high (H) and low (L) responder lines selected for antibody response to complex immunogens. Data were recorded in normal and postimmunization sera from the H and L lines produced by five independent selective breedings (selections I, II, III, IV, and V). Ig levels were much higher in H than in L mice of all the selections. In four selections this interline difference increased further after immunization with the selection antigens. This is in agreement with the general effect of the polygenic control of antibody responses operating in H and L lines. The Ig isotype profiles of normal sera were different in each line; however, similitudes were noticed between H and L lines in selections I and II. In contrast, in selections III, IV, and V a similar interline difference was observed: the lack of IgG2a isotype in L lines only. After immunization there were minor alterations of the isotype profiles except in the H lines of selections III and IV, in which a clear inverse modification of IgG1 and IgG2a proportions occurred. The characteristic pattern of each selection may be partially dependent on isotype-restricted regulatory effects in relation to the immunization procedure used for selective breeding.

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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.

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A pesquisa de Escherichia coli enterotoxigenica em esgoto aguas superficiais e agua potavel contaminada revelou a presenca dessa bacteria em sete (1,9%) das 365 amostras de esgoto e em 12 (2,4%) das 495 amostras de agua examinadas. Todas as cepas, com excecao de uma, produziram somente enterotoxina termolabil e nenhuma delas apresentou os fatores de colonizacao CFA/I e CFA/II. A maioria das cepas foi sensivel aos antibioticos testados. Grande diversidade de sorotipos foi encontrada, alguns dos quais associados com diarreia em humanos

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Dezoito amostras de Escherichia coli produtoras de toxina LT, isoladas de criancas, foram estudadas em relacao a resistencia a drogas e producao de colicinas, hemolisinas e H2S. Oito amostras eram sensiveis as drogas utilizadas e negativas em relacao as demais caracteristicas. Uma amostra somente produziu colicina. As outras nove linhagens apresentaram diferentes padroes de resistencia (1 a 7 drogas) e uma delas tambem produziu colicina. Foi observado atraves de experimentos de conjugacao que em seis dessas amostras os plasmidios R eram transferidos e 4 delas tambem transferiam o plasmidio Ent. A producao de colicina pelos transconjugantes so foi observada atraves de estudos de cotransferencia. Esses estudos e eletroforese em gel de agarose mostraram que nas seis amostras os genes que cidificam para LT, colicinas e resistencia a drogas estao localizados em plasmidios independentes.Foi observado que a transferencia de plasmidios R ocorreu nas 4 amostras e do plasmidio Ent em 3 das amostras resistentes, isoladas de criancas com diarreia enquanto que a transferencia desses plasmidios e menor entre as amostras resistentes isoladas de criancas sadias

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An inflammatory skin reaction similar to the permeability factor (PF) described for the thermolabile (TL) enterotoxin of Escherichia coli was induced in rabbits inoculated intradermally with supernatants from cultures of Salmonella typhimurium and S. enteritidis. This PF-like activity was observed with both crude supernatants as well as those which were submitted to gel filtration through Sephadex G-100. PF-like activity was found only in fraction 1 (F1) of the chromatographed materials. It was resistant to boiling, proteolytic enzymes and wide variations of pH. Serological studies based on agglutination and immunodiffusion tests demonstrated that F1 materials were closely related to the somatic antigen of group B Salmonella. No specific TL activity, as detected by the Y-1 adrenal cell assay and the passive immune haemolysis test, could be demonstrated. Furthermore, F1 materials were not enterotoxigenic as assayed by the rabbit ileal loop assay, and no neutralization of PF-like activity could be obtained in tests carried out using F1 preparations pre-incubated with either anti-F1 or cholera antitoxin. Based upon these findings, it seems reasonable to suppose that most PF reactions, already reported as being caused by a TL-like enterotoxin produced by Salmonella, are probably due to endotoxin. In fact, this possibility was reinforced by the Sanarelli-Shwartzman phenomenon which was produced in rabbits inoculated with F1 materials.

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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.

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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.

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Nove linhagens de E. coli isoladas de hamburgers, quibes ou linguicas cruas e produtoras da toxina LT foram estudadas quanto a resistencia a drogas e producao de colicina, hemolisina e H2S. Cinco linhagens mostraram-se sensiveis as drogas utilizadas e negativas as demais caracteristicas. Tres linhagens apresentaram o fenotipo SmTcHlyCol LT e uma o fenotipo SmTcHly LT. Essas quatro linhagens foram conjugadas com a E. coli K12 MA335. Os genes de resistencia a drogas foram transferidos em todos os experimentos de conjugacao. Duas linhagens transferiram o plasmidio Col, uma linhagem o plasmidio Hly e a terceira o plasmidio Ent. As evidencias sao de que as caracteristicas estudadas estao localizadas em plasmidios independentes

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EA (eritrocitos de carneiro, sensibilizados com anticorpos de coelho) sao lisados por complemento de sapo em condicoes otimas, que consistem no uso de uma baixa concentracao de celulas (1.54 x 10 elevado a 8/ml), incubacao a baixa temperatura (30 graus centigrados) e as mesmas quantidades de Ca++ e de Mg++, requeridas para a titulacao de atividade hemolitica do complemento de cobaia. Estudos cineticos de efeito dos cations mencionados acima na imune-lise produzida pelo complemento de cobaia. Num sistema limitado pela quantidade de complemento, lise pelo C de anfibio e totalmente bloqueada e apenas parcial. Os achados experimentais sugerem que Mg++ seja requerido nao apenas no estagio inicial, mas tambem em estagios tardios do processo litico e permitem especular que a ativacao do complemento de anfibio se processa predominantemente pela via alternativa

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