RESUMO
Daily ingestion of a probiotic drink containing Lactobacillus casei Shirota (LcS; 1.3 × 1010 live cells) by healthy adults for (1) 4-week LcS, (2) 6-week discontinuation of LcS and (3) a final 4 weeks of LcS was investigated. There was a significant increase in expression of the T cell activation marker CD3+ CD69+ in ex vivo unstimulated blood cells at weeks 10 and 14, and there was a significant increase in the NK cell marker CD3+ CD16/56+ in ex vivo unstimulated blood cells at weeks 4, 10 and 14. Expression of the NK cell activation marker CD16/56+ CD69+ in ex vivo unstimulated blood cells was 62% higher at week 10 and 74% higher at week 14. Intracellular staining of IL-4 in ex vivo unstimulated and PMA-/ionomycin-stimulated CD3+ ß7+ integrin blood cells was significantly lower at weeks 10 and 14. Intracellular staining of IL-12 in ex vivo unstimulated and LPS-stimulated CD14+ blood cells was significantly lower at weeks 4, 10 and 14. Intracellular staining of TNF-α in LPS-stimulated CD14+ blood cells was significantly lower at weeks 4, 10 and 14. Mucosal salivary IFN-γ, IgA1 and IgA2 concentrations were significantly higher at week 14, but LcS did not affect systemic circulating influenza A-specific IgA or IgG and tetanus-specific IgG antibody levels. In addition to the decrease in CD3+ ß7+ integrin cell IL-4 and a reduced CD14+ cell pro-inflammatory cytokine profile, at week 14 increased expression of activation markers on circulating T cells and NK cells and higher mucosal salivary IgA1 and IgA2 concentration indicated a secondary boosting effect of LcS.
Assuntos
Linfócitos B/imunologia , Imunoglobulina A/imunologia , Células Matadoras Naturais/imunologia , Lacticaseibacillus casei/imunologia , Probióticos/administração & dosagem , Linfócitos T/imunologia , Adolescente , Adulto , Antígenos CD/imunologia , Células Cultivadas , Feminino , Voluntários Saudáveis , Humanos , Cadeias beta de Integrinas/imunologia , Interferon gama/imunologia , Interleucina-4/imunologia , Ativação Linfocitária , Masculino , Saliva/imunologia , Fator de Necrose Tumoral alfa/imunologia , Adulto JovemRESUMO
Modulation of host immunity is an important potential mechanism by which probiotics confer health benefits. This study was designed to investigate the effects of a probiotic strain, Lactobacillus casei Shirota (LcS), on immune function using human peripheral blood mononuclear cells (PBMC) in vitro. In addition, the role of monocytes in LcS-induced immunity was also explored. LcS promoted natural killer (NK) cell activity and preferentially induced expression of CD69 and CD25 on CD8(+) and CD56(+) subsets in the absence of any other stimulus. LcS also induced production of interleukin (IL)-1beta, IL-6, tumour necrosis factor (TNF)-alpha, IL-12 and IL-10 in the absence of lipopolysaccharide (LPS). In the presence of LPS, LcS enhanced IL-1beta production but inhibited LPS-induced IL-10 and IL-6 production, and had no further effect on TNF-alpha and IL-12 production. Monocyte depletion reduced significantly the impact of LcS on lymphocyte activation, cytokine production and natural killer (NK) cell activity. In conclusion, LcS activated cytotoxic lymphocytes preferentially in both the innate and specific immune systems, which suggests that LcS could potentiate the destruction of infected cells in the body. LcS also induced both proinflammatory and anti-inflammatory cytokine production in the absence of LPS, but in some cases inhibited LPS-induced cytokine production. Monocytes play an important role in LcS-induced immunological responses.
Assuntos
Citocinas/metabolismo , Células Matadoras Naturais/imunologia , Lacticaseibacillus casei/imunologia , Ativação Linfocitária/imunologia , Probióticos , Linfócitos T/imunologia , Adulto , Antígenos CD/metabolismo , Antígenos de Diferenciação de Linfócitos T/metabolismo , Sangue/efeitos dos fármacos , Sangue/imunologia , Sangue/metabolismo , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Separação Celular , Células Cultivadas , Concanavalina A/farmacologia , Citotoxicidade Imunológica/imunologia , Humanos , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Interleucinas/metabolismo , Lectinas Tipo C/metabolismo , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Lipopolissacarídeos/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Monócitos/citologia , Monócitos/imunologia , Monócitos/metabolismo , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
AIMS: To prepare 1,5-anhydro-d-fructose (AF) derivatives, test their microbial inhibition spectrum, and to further examine the most effective AF derivative against Pseudomonas aeruginosa and malignant blood cell lines. METHODS AND RESULTS: Microthecin and nine other AF derivatives were synthesized from AF. The 10 compounds were tested in vitro against Gram-positive (GP) and Gram-negative (GN) bacteria, yeasts and moulds using a well diffusion method and in a Bioscreen growth analyser. Of the test compounds, microthecin exhibited the most significant antibacterial activity at 100-2000 ppm against both GP and GN bacteria, including Ps. aeruginosa. Further tests with three malignant blood cell lines (Mutu, Ramos, Raji) and one normal cell line indicated that microthecin was a cell toxin, with a cell mortality >85% at 50 ppm. The other nine AF derivatives demonstrated low or no antimicrobial activity. CONCLUSIONS: Microthecin was active 100-2000 ppm against GP and GN bacteria including Ps. aeruginosa, but was inactive against yeasts and moulds. Microthecin was also a cytotoxin to some mammalian cell lines. SIGNIFICANCE AND IMPACT OF THE STUDY: Microthecin might have potential for development as a novel drug against Ps. aeruginosa and to target cancer cells. It might also be developed as a food processing aid to control bacterial growth.
Assuntos
Frutose/análogos & derivados , Fungos/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Cetoses/farmacologia , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Meios de Cultura/metabolismo , Meios de Cultura/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Frutose/farmacologia , Humanos , Testes de Sensibilidade MicrobianaRESUMO
AIMS: To assess the antimicrobial efficacy of ascopyrone P (APP), a secondary metabolite formed by the fungi Anthracobia melaloma, Plicaria anthracina, Plic. leiocarpa and Peziza petersi belonging to the order Pezizales. METHODS AND RESULTS: In vitro testing using a well diffusion procedure showed that APP at a high concentration (approximately 5%) inhibited the growth of Gram-positive and Gram-negative bacteria. Using an automated microbiology reader, growth curve analysis showed that 2000-4000 mg l(-1) APP caused total or significant bacterial inhibition after incubation for 24 h at 30 degrees C. Against certain yeast strains, 1000- 2000 mg l(-1) APP enhanced growth, although at higher concentrations inhibition of some yeasts was observed. Clostridium and fungal strains were not sensitive to 2000 mg l(-1) APP. No significant cidal effect was observed after 2 h against Listeria monocytogenes or Escherichia coli. Results were identical whether the APP samples tested had been produced enzymatically or chemically. CONCLUSIONS: At a level of 2000 mg l(-1), APP demonstrated growth inhibitory activity against a broad range of bacteria, but not yeasts or moulds. SIGNIFICANCE AND IMPACT OF THE STUDY: A possible application for this novel natural antimicrobial is in food preservation, to control the growth of Gram-negative and Gram-positive bacteria in raw and cooked foods. Effective dosage levels would be 500-4000 mg kg(-1), depending on food type. The efficacy, organoleptic and safety aspects of this compound in food still need to be assessed.
Assuntos
Antibacterianos/metabolismo , Antibacterianos/farmacologia , Ascomicetos/metabolismo , Frutose/análogos & derivados , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Ascomicetos/crescimento & desenvolvimento , Frutose/metabolismo , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana/métodosRESUMO
Lactic acid bacteria (LAB) commonly cause spoilage in minimal heat-treated vacuum-packed cured delicatessen meats. Predominant species are Lactobacillus sake and L. curvatus. LAB strains isolated from spoiled products of this type (liver sausage, ham and bologna sausage) were found to be sensitive to low nisin concentrations (maximum of 1.25 microg g(-1)). Addition of 25 microg g(-1) nisin (as Nisaplin) inhibited the growth of LAB spoilage organisms inoculated into vacuum-packed pasteurized bologna-type sausages stored at 8 degrees C. Control sausages became spoiled (>10(8) LAB CFU g(-1)) by day 7, whereas sausages containing nisin remained unspoiled for >50 days. The effect of three types of phosphates (used as emulsifiers) on nisin activity in the sausages was compared. LAB growth rate was fastest in samples containing orthophosphate, and slowest in sausages containing diphosphate. The shelf life was also greatly extended in the latter. Fat content also affected nisin activity. Nisin activity (as indicated by LAB inhibition) was greatest in samples containing 15% > 25% > 37% (wt/wt) fat. In a sausage formulation containing 37% fat and incorporating diphosphate as emulsifier, levels of nisin as low as 2.5 microg g(-1) showed antibacterial effects. A nisin level of 6.25 microg g(-1) totally inhibited LAB growth for over 4 weeks and 25 microg g(-1) for 5 weeks. Spoilage control was achieved in the same sausage formulation but with 25% (wt/wt) fat; 12.5 microg g(-1) nisin prevented LAB growth for 5 weeks.
Assuntos
Conservantes de Alimentos/farmacologia , Lactobacillus/efeitos dos fármacos , Produtos da Carne/microbiologia , Nisina/farmacologia , Animais , Antibacterianos/farmacologia , Bovinos , Excipientes/farmacologia , Gorduras/farmacologia , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Lactobacillus/crescimento & desenvolvimento , Fosfatos/farmacologia , Suínos , Fatores de TempoRESUMO
Nisin in combination with the sucrose fatty acid esters, sucrose palmitate (P-1570 and P-1670) or sucrose stearate (S-1570 and S-1670) was tested against a range of Gram-negative and Gram-positive bacteria. Initial liquid culture investigation showed that the sugar ester P-1670 resulted in a synergist enhancement of the bacteriostatic activity of nisin against Gram-positive bacteria and not Gram-negative bacteria. Some enhancement of the bactericidal activity of nisin against Listeria monocytogenes was also observed. This increased nisin inhibitory effect was confirmed on solid media using plates with gradients of pH and NaCl. Synergism was observed with all four sucrose fatty acid esters, which enhanced the antimicrobial activity of nisin against several strains of L. monocytogenes, Bacillus cereus (both cells and spores), Lactobacillus plantarum and Staphylococcus aureus. The combination of nisin and the sucrose fatty acid esters showed no inhibition of Gram-negative bacteria (Salmonella enteritidis, Salm. typhimurium and Pseudomonas aeruginosa).
Assuntos
Antibacterianos/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Nisina/farmacologia , Tensoativos/farmacologia , Sinergismo Farmacológico , Ésteres/farmacologia , Ácidos Graxos/farmacologia , Sacarose/análogos & derivadosRESUMO
Gradient plates were used to investigate the effects of varying temperature, pH, and sodium chloride (NaCl) concentration on nisin inhibition of Staphylococcus aureus and Listeria monocytogenes, Nisin was incorporated into the plates of 0, 50, 100, 250, and 500 IU ml -1. Gradients of pH (3.7 to 7.92) at right angles to NaCl concentration (2.1 to 7% [wt/vol]) were used for the plates, which were incubated at 20, 25, 30 and 35 degrees C. Growth on the plates were recorded by eye and by image analysis. The presence of viable but nongrowing cells was revealed by transfer to nongradient plates. Lower temperatures and greater NaCl concentrations increased the nisin inhibition of S. aureus synergistically. Increasing the NaCl concentration potentiated the nisin action against L. monocytogenes; the effect of temperature difference was not so apparent. Between pH 7.92 and ca. pH 5, a fall pH appeared to increase nisin's effectiveness against both organisms. At more acid pH values (ca. pH 4.5 to 5), the organisms showed resistance to both nisin and NaCl at 20 and 25 degrees C. Similar results were obtained with one-dimensional liquid cultures.
Assuntos
Antibacterianos/farmacologia , Conservantes de Alimentos/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Nisina/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Resistência Microbiana a Medicamentos , Concentração de Íons de Hidrogênio , Listeria monocytogenes/crescimento & desenvolvimento , Cloreto de Sódio/farmacologia , Staphylococcus aureus/crescimento & desenvolvimento , TemperaturaRESUMO
pH/sodium chloride (NaCl) gradient plates were used to investigate competition between Pseudomonas and Salmonella species. At 30 degrees C and at particular NaCl/pH conditions the salmonellae inhibited growth of P. fluorescens and not P. putida. At 20 degrees C P. putida and not P. fluorescens inhibited the salmonellae. The growth of the pure and mixed strains in agar plates with the pH/NaCl conditions was compared by viable counts. Competition in pour plates at 30 degrees C was confirmed. At 20 degrees C, sub-surface growth of the salmonellae inhibited the P. putida. With surface growth this did not occur; the salmonellae was slightly inhibited by the P. putida.
Assuntos
Antibiose , Meios de Cultura/química , Pseudomonas/crescimento & desenvolvimento , Salmonella/crescimento & desenvolvimento , Temperatura , Ágar , Contagem de Colônia Microbiana , Concentração de Íons de Hidrogênio , Cloreto de SódioRESUMO
Gel-stabilized two-dimensional gradient plates were used to study the effects of pH, salt concentration and temperature on the conjugal transfer of plasmid RP4 between strains of Escherichia coli and Pseudomonas putida. The combinations of pH and salt concentration that permitted conjugation were mapped as a two-dimensional growth area occupied by transconjugants following conjugation. This conjugation domain was less extensive than the areas that supported growth of the parental strains, and showed evidence for the interactive effects of pH and salt concentration in determination of conditions that permitted conjugation. The size and shape of the conjugation domain was influenced by time, temperature, the identities of the donor and recipient bacteria, and the combination of donor and recipient bacteria.
Assuntos
Conjugação Genética , Escherichia coli/genética , Plasmídeos/genética , Pseudomonas putida/genética , Escherichia coli/crescimento & desenvolvimento , Técnicas de Transferência de Genes , Concentração de Íons de Hidrogênio , Biologia Molecular/instrumentação , Pseudomonas putida/crescimento & desenvolvimento , Cloreto de Sódio/farmacologia , Temperatura , Fatores de TempoRESUMO
Competition between microorganisms as affected by temperature, pH, and the sodium chloride (NaCl) concentration was investigated by selective replication from gradient plates. Salmonella typhimurium was inhibited by Pseudomonas putida at 20 and 23 degrees C but not 30 and 35 degrees C. P. putida no longer grew at the extremes of pH and NaCl concentration, particularly at 30 and 35 degrees C.
RESUMO
The effect of temperature, pH, sodium chloride concentration and a preservative (sodium benzoate, sodium nitrite or potassium sorbate) on the growth of three foodborne bacterial pathogens (Bacillus cereus, Vero cytotoxigenic Escherichia coli and Staphylococcus aureus) was studied using gradient gel plates. Growth, expressed in optical density units, was recorded using image analysis techniques, and was expressed as three-dimensional grids. These gave a visual indication of the effects of any three of the environmental factors on bacterial proliferation. Sorbate was completely effective against E. coli at all temperature/pH/NaCl combinations, and was the most effective preservative tested against B. cereus. Increase in the acidity and/or the NaCl concentration improved the effect of all the preservatives, except nitrite when used against St. aureus. Nitrite was the least effective preservative, particularly against St. aureus. At < 25 degrees C, sorbate was more effective than benzoate against St. aureus when used with higher concentrations of NaCl. At 35 degrees C benzoate was the most effective preservative against St. aureus, especially when used at pH < 6.
Assuntos
Bacillus cereus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Microbiologia de Alimentos , Conservantes de Alimentos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Bacillus cereus/crescimento & desenvolvimento , Toxinas Bacterianas/biossíntese , Técnicas Bacteriológicas , Benzoatos/farmacologia , Ácido Benzoico , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Estudos de Avaliação como Assunto , Conservação de Alimentos/métodos , Doenças Transmitidas por Alimentos/prevenção & controle , Concentração de Íons de Hidrogênio , Toxina Shiga I , Cloreto de Sódio , Nitrito de Sódio/farmacologia , Ácido Sórbico/farmacologia , Staphylococcus aureus/crescimento & desenvolvimento , TemperaturaRESUMO
Six Salmonella strains were grown on two-dimensional sodium chloride-pH and temperature-pH gradient plates. Using image analysis the results were expressed in the form of three-dimensional wire frame graphs. On the temperature-pH gradient plates the optimum growth range was 20-30 degrees C and the minimum pH for visible growth was ca. pH 4, except for strain S. typhimurium CRA63 which grew over a narrower temperature and pH range. On the NaCl-pH gradient plates (whose NaCl gradient began at 2.75% (w/v) NaCl) the maximum concentration of salt at which growth was visible varied from 3.9% to 6.0%, and the minimum pH at which growth was observed varied from pH 4.7 to 5.4 according to the strain used. The incorporation of 0.02% (w/v) sodium nitrite reduced the maximum salt concentration and increased the minimum pH at which the strains could grow. The strains were combined and used in a mixed inoculum on NaCl-pH gradient plates containing 6 different concentrations of NaNO2 incubated at 6 different temperatures. Comparison of the data from the mixed inoculum with data from individual strains showed that, apart from one case, the mixed inoculum represented the extremes of the growth domains of the individual strains. The effect of NaNO2 on the ability of the strains to grow at different pH, NaCl concentrations and temperatures, was more clearly shown by subtracting the data of plates containing NaNO2 from the data of plates without NaNO2.
Assuntos
Salmonella typhimurium/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Processamento de Imagem Assistida por Computador , Salmonella typhimurium/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Nitrito de Sódio/farmacologia , TemperaturaRESUMO
The effect of four variables (pH, temperature, sodium chloride concentration and sodium nitrite concentration) on the growth of Salmonella typhimurium CRA663 was investigated using a two-dimensional gradient gel technique. Two methods were used. In the first method the gradients comprised NaCl and pH and in the second method a temperature gradient incubator was used to produce a temperature-pH gradient. Using image analysis, the growth on the plates was depicted as three-dimensional wire frame graphs. At neutral pH and in conditions of low salt, growth was observed over the temperature gradient range of 14-41 degrees C. The optimum growth range was reduced to 21-29 degrees C in conditions of acid pH and/or increased NaCl concentration. The growth on the temperature-pH gradient plates had an irregular surface appearance suggesting that changes in growth rate were occurring at different points of temperature and pH. The effects of increased salt concentration together with acidic pH increased the inhibitory effect of the sodium nitrite. The gradient gel plate technique may be a means of rapidly screening the effect of multiple variables on the growth on microorganisms that may be found in food.
Assuntos
Microbiologia de Alimentos , Salmonella typhimurium/crescimento & desenvolvimento , Cloreto de Sódio/farmacologia , Nitrito de Sódio/farmacologia , Meios de Cultura , Concentração de Íons de Hidrogênio , Salmonella typhimurium/efeitos dos fármacos , TemperaturaRESUMO
A total of 1,255 strains of motile, mesophilic Aeromonas species isolated from clinical and environmental specimens in the United Kingdom and 258 strains isolated in Australia, Brazil, Peru, and the United States were examined by using antisera for serogroups O1 to O44 (R. Sakazaki and T. Shimada, Jpn. J. Med. Sci. 37:247-255, 1984) and for unpublished serogroup O45 (R. Sakazaki). The typeability rate for strains isolated in the United Kingdom was 35%; the strains isolated in other countries had typeability rates of between 14 and 43%. A total of 52 provisional new serogroups were identified, and the strains with unidentified O groups were examined by using antisera for these provisional new serogroups. The typeability rate for strains isolated in the United Kingdom was increased to 66% (70% of smooth strains). The typeability rates were 76% for A. hydrophila and 63% for both A. caviae and A. sobria. The 52 antisera for the provisional new serogroups increased the typeability rate for strains isolated outside the United Kingdom to between 43 and 68%. This extended serogrouping scheme would be of value in determining the importance of Aeromonas strains as human intestinal pathogens and in investigating the pathogenic mechanisms that may be involved in the production of diarrheal disease.
Assuntos
Aeromonas/classificação , Aeromonas/isolamento & purificação , Aeromonas/patogenicidade , Movimento Celular , Diarreia/etiologia , Diarreia/microbiologia , Fezes/microbiologia , Humanos , Sorotipagem , Temperatura , Reino Unido , Microbiologia da ÁguaRESUMO
Four bacterial strains are described that possess the biochemical characteristics of Shigella species but do not belong to any of the established Shigella serovars or to any previously described provisional serovar. One strain fermented mannitol, and it is proposed that this be the type strain for a new provisional serovar of Shigella boydii. The remaining strains did not ferment mannitol and belonged to three different serovars. These strains are proposed as type strains for three new provisional serovars of Shigella dysenteriae. All four strains were invasive in a HEp-2 cell tissue culture test, but only one was invasive in the guinea pig eye test and might therefore be expected to cause dysenterylike illness in humans. It is important that the designation of such strains remain provisional until other reference laboratories have had the opportunity to search for additional isolates and the possible pathogenicity of these strains for humans can be further assessed.
Assuntos
Shigella dysenteriae/classificação , Testes de Aglutinação , Animais , Antígenos de Bactérias/análise , Resistência Microbiana a Medicamentos , Fermentação , Cobaias , Humanos , Manitol/metabolismo , Sorotipagem , Shigella dysenteriae/efeitos dos fármacos , Shigella dysenteriae/imunologia , Shigella dysenteriae/patogenicidadeRESUMO
Enterotoxigenic Escherichia coli producing coli surface antigen 4 (CS4), CS5, and CS6 of colonization factor antigen IV were examined. This factor was originally called putative colonization factor 8775 (PCF8775). All of the coli surface antigens were plasmid coded and were usually carried on the same plasmid as the genes coding for heat-stable toxin (ST) or heat-labile toxin (LT); thus, CS5-CS6-ST, CS6-ST, and CS6-LT plasmids were found. In strains of serotype O25:H42, the genes coding for CS4 and CS6 were on a plasmid separate from that containing the genes coding for ST and LT. CS4 and CS5 were fimbrial antigens with a subunit molecular mass of about 17.0 and 21.0 kilodaltons (kDa), respectively. CS6 was found as a single polypeptide with a molecular mass of about 14.5 kDa in strains of serotypes O25:H42, O27:H7, and O27:H20 when heated extracts were run on sodium dodecyl sulfate-polyacrylamide gels. CS6-positive extracts of strains of serogroups O148, O159, and O167 showed two bands with molecular masses between 14.5 and 16.0 kDa.
Assuntos
Antígenos de Bactérias/genética , Antígenos de Superfície/genética , Aderência Bacteriana , Escherichia coli/genética , Proteínas de Fímbrias , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , DNA Bacteriano/genética , Enterotoxinas/genética , Ensaio de Imunoadsorção Enzimática , Epitopos , Escherichia coli/imunologia , Escherichia coli/patogenicidade , Genes Bacterianos , Imunodifusão , Peso Molecular , Plasmídeos , SorotipagemRESUMO
Sertoli cells produce lactate and pyruvate as energy substrates for the developing germ cells in the testis. Since the Sertoli cells are thought to be the initial target for phthalate esters causing testicular atrophy, the effect of some phthalates on lactate and pyruvate production by primary Sertoli cell-enriched cultures was studied. Mono-(2-ethylhexyl) phthalate (0.1-200 microM) produced a concentration-dependent stimulation of lactate, but not pyruvate production over a 24 h treatment period and an increase in the ratio of lactate/pyruvate concentration in the culture medium. Di-(2-ethylhexyl) phthalate and 2-ethylhexanol (200 microM) had no such effects. Other phthalate monoesters known to cause testicular atrophy also increased Sertoli cell lactate production and the lactate/pyruvate ratio, whereas monoesters not associated with testicular damage in vivo had no such effects. The results suggest that loss of germ cells in phthalate-induced testicular atrophy is not due to inhibition of energy substrate production by the Sertoli cells and that stimulation of lactate production may be a useful in vitro marker for phthalate esters and related compounds that cause testicular injury.
Assuntos
Lactatos/metabolismo , Ácidos Ftálicos/toxicidade , Plastificantes/toxicidade , Piruvatos/metabolismo , Células de Sertoli/efeitos dos fármacos , Animais , Dietilexilftalato/toxicidade , Técnicas In Vitro , Masculino , Ratos , Células de Sertoli/metabolismo , Relação Estrutura-AtividadeRESUMO
The metabolism and tissue distribution of [14C]deoxynivalenol have been studied in male PVG rats. Following administration of a single oral 10-mg/kg dose, radioactivity excreted in the urine and faeces accounted, respectively, for 25 and 64% of the administered dose within 96 hr. Less than 0.15% of the dose was detected in the respired air. Very little radioactivity appeared to be retained in any of the tissues examined after 96 hr. HPLC separation of several urinary and faecal metabolites was achieved on a reversed-phase column, using two different elution systems, one at neutral pH and one acidified. Two of the major non-polar HPLC peaks were identified by gas chromatography-mass spectrometry as unchanged deoxynivalenol and 3 alpha,7 alpha,15-trihydroxytrichothec-9,12-dien-8-one.