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Sarciron ME Nebois P Pautet F Pétavy AF Fillion H Walchshofer N 《Parasitology research》2002,88(11):969-971
Quinonic derivatives were tested against a virulent RH strain of Toxoplasma gondii maintained in cell culture in THP-1, a human myelomonocytic cell line. The derivatives were tested at various doses (0.5-4 microg/ml) and compared with the reference molecules clindamycine, sulfadiazine, pyrimethamine and atovaquone. The percentage of parasite growth inhibition was observed after 72 h of incubation. The tested derivatives are bicyclic, tricyclic or tetracyclic quinones. Eight of these compounds exhibit over 70% inhibition of parasite growth; and two were nearly equipotent to pyrimethamine. These data indicate that the most active compounds against the RH strain of T. gondii are bis-heterocyclic quinones. 相似文献
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We tested 124 isolates of Toxoplasma gondii, as determined morphologically and by their ability to elicit antibodies in the dye test with the RH strain of Toxoplasma in mice. They were compared for their capacity to immunize CF-1 mice against isolate T-1, and T-1 immune mice for their capacity to resist each of the 123 other isolates. Of the 125 isolates, 52 had been isolated in the continental USA, 33 in Central America, 15 in Europe, 9 in Hawaii, five in Japan, two in Taiwan, five in Australia, one in Indonesia, one in Tunisia, and one was of unknown origin. Complete cross-immunity was found. This suggests that only one immunotype of Toxoplasma is prevalent in the United States, and perhaps all over the earth. Vaccines are likely to immunize against most or all Toxoplasma isolates. 相似文献
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We conducted this study to describe the serum electrophoretic pattern in dogs associated with the infection of Toxoplasma gondii (T. gondii). The serum protein pattern of 25 dogs with confirmed T. gondii infection and 15 clinically healthy dogs were evaluated using native polyacrylamide gel electrophoresis. Albumin, alpha-1
globulin, alpha-2 globulin, beta globulin, and gamma globulin bands were seen from the serum electrophoresis of infected and
healthy dogs. Compared to the control group, significant decreases in the mean percentages of albumin (from 46.1 ± 7.2 to
40.8 ± 4.5%, P < 0.05), alpha-1 globulin (from 3.9 ± 0.4 to 0.8 ± 0.2%, P < 0.001), alpha-2 globulin (from 9.0 ± 0.4 to 8.3 ± 0.8%, P < 0.01), and beta globulin (from 18.4 ± 1.2 to 12.1 ± 0.6%, P < 0.001) in the infected group were determined. In contrast, gamma globulin fraction was significantly higher in infected
dogs (38.1 ± 4.6%) than in control dogs (22.7 ± 7.2%; P < 0.001). Moreover, significant correlations were determined between the percentages of the albumin and gamma globulin fractions
and liver enzyme tests including aspartate aminotransferase and alanine aminotransferase in infected dogs; however, no correlation
was observed for the other protein fractions. In conclusion, marked alterations in serum protein pattern associated with strong
modifications of serum protein concentrations are in accordance with the hepatic injury as affirmed by liver enzyme tests
that were demonstrated in the canine toxoplasmosis. These findings showed that serum protein electrophoresis can be used in
the diagnosis and prognosis of canine toxoplasmosis as a supplementary analysis in combination with serological, clinical,
and laboratory findings of this disease. 相似文献
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Malo-ethanolic fermentation in<Emphasis Type="Italic"> Saccharomyces</Emphasis> and<Emphasis Type="Italic"> Schizosaccharomyces</Emphasis> 总被引:1,自引:0,他引:1
Yeast species are divided into the K(+) or K(–) groups, based on their ability or inability to metabolise tricarboxylic acid (TCA) cycle intermediates as sole carbon or energy source. The K(–) group of yeasts includes strains of Saccharomyces, Schizosaccharomyces pombe and Zygosaccharomyces bailii, which is capable of utilising TCA cycle intermediates only in the presence of glucose or other assimilable carbon sources. Although grouped together, these yeasts have significant differences in their abilities to degrade malic acid. Typically, strains of Saccharomyces are regarded as inefficient metabolisers of extracellular malic acid, whereas strains of Sch. pombe and Z. bailii can effectively degrade high concentrations of malic acid. The ability of a yeast strain to degrade extracellular malic acid is dependent on both the efficient transport of the dicarboxylic acid and the efficacy of the intracellular malic enzyme. The malic enzyme converts malic acid into pyruvic acid, which is further metabolised to ethanol and carbon dioxide under fermentative conditions via the so-called malo-ethanolic (ME) pathway. This review focuses on the enzymes involved in the ME pathway in Sch. pombe and Saccharomyces species, with specific emphasis on the malate transporter and the intracellular malic enzyme.Communicated by S. Hohmann 相似文献
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Bresciani KD Gennari SM Serrano AC Rodrigues AA Ueno T Franco LG Perri SH Amarante AF 《Parasitology research》2007,100(2):281-285
The occurrence of antibodies to Neospora caninum and Toxoplasma gondii was determined in 400 domestic cats (Siamese, Persian, and undetermined breeds) from the Municipality of Araçatuba, Sao Paulo, Brazil, through the indirect fluorescence antibody test (IFAT). Of the 400 cats, 100 were seropositive to T. gondii (25%, titer ≥64) and 98 to N. caninum (24.5%, titer ≥16). The rate of seropositive cats for T. gondii was correlated with age (χ 2=35.7; p<0.001), with a higher number of infected animals at older ages. Of the 219 cats younger than 1-year-old, 13.2% were seropositive for T. gondii, while 39.2% were positive in the 181 older animals. The presence of N. caninum was also correlated with age (÷2=8.8; p<0.01), with 18.7% (41/219) and 31.5% (57/181) of positive animals at ages below and above 12-month, respectively. An association between the occurrences of both protozoa in the felines was also observed (χ 2=19.6; p<0.001). 相似文献
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Recent studies have shown that hormones could induce anti-parasitic functions of the host immune system; thus, the aim of
the present study was to estimate the seroprevalence of Toxoplasma gondii antibodies by an enzyme-linked immunosorbent assay in a Polish population of women and men with hyperprolactinaemia (n = 234) and hypoprolactinaemia (n = 41) and in a control group (n = 281) with the physiological level of prolactin (PRL). Women with hyperprolactinaemia revealed lower seroprevalence than
those with normal PRL level (33.90% and 45.58%, respectively; p = 0.025). Detailed analysis of the results showed that twofold, threefold, fourfold and fivefold increase of the PRL concentration
above the normal was correlated to the decrease of the T. gondii seroprevalence, but only in the group of women with a very high PRL level (>86 ng/ml) seroprevalence (12.50%) was significantly
lower (p = 0.0004) than in the control subjects. These results confirm previously described suggestions on the relationship between
hyperprolactinaemia and parasitic infection frequency. We postulate that a high level of PRL may be one of the important factors
preventing T. gondii infection in women. 相似文献
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In the fungus Fusarium sporotrichioides, biosynthesis of trichothecene mycotoxins requires at least three genetic loci: a core 12-gene cluster, a smaller two-gene cluster, and a single-gene locus. Here, we describe the Tri15 gene, which represents a fourth locus involved in trichothecene biosynthesis. Tri15 is predicted to encode a Cys2-His2 zinc finger protein and is expressed in a manner similar to genes in the core trichothecene gene cluster. However, disruption of F. sporotrichioides Tri15 does not affect production of T-2 toxin, the major trichothecene produced by this fungus. This result suggests that Tri15 is not necessary for the production of toxin. Cultures with exogenously added T-2 toxin have high levels of Tri15 expression and no detectable expression of the trichothecene biosynthetic genes Tri5 and Tri6. The expression analysis is consistent with Tri15 being a negative regulator of at least some of the trichothecene biosynthetic genes. In F. graminearum, Tri15 has been mapped to linkage group 2 and is therefore unlinked to the main trichothecene biosynthetic gene cluster.Communicated by U. Kück 相似文献
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The use of CpG as an adjuvant to<Emphasis Type="Italic"> Toxoplasma gondii</Emphasis> vaccination 总被引:1,自引:0,他引:1
Unmethylated CpG dinucleotides have been found to stimulate general immune responses in mammals. CpG motifs have further been shown to be potent adjuvants when used in conjunction with vaccines for viral and bacterial organisms. It was necessary to determine whether these CpG motifs will also enhance immune responses in parasitic diseases. We therefore decided to test the effect of CpG adjuventation on immunization with a temperature-sensitive mutant (ts4) strain of Toxoplasma gondii. Mice were divided into groups receiving either ts4 only, CpG only, ts4 with CpG, or untreated controls. Mice were challenged with a lethal dose of T. gondii (RH strain) tachyzoites 28 days after vaccination. There were significant differences observed between the ts4-only group and the other three groups with regards to antibody isotype and survival, with the former group surviving lethal challenge. CpG adjuventation appeared to not enhance survival. 相似文献
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Toxoplasma gondii is an obligate intracellular protozoan which infects most species of warm-blooded animals and causes toxoplasmosis. Previous
immunological and immunization studies have demonstrated the potential role of T. gondii antigens SAG1 and GRA2 as a vaccine candidate. In the present study, we have cloned, expressed, and purified a recombinant
protein SAG1–GRA2 in Pichia pastoris. Results showed that P. pastoris was a robust system producing a large amount of highly purified and biological activity protein. BALB/c mice immunized with
SAG1–GRA2 elicited stronger humoral and cellular responses in comparison to control groups. This immunization resulted in
an enhanced Th1 immune response as measured by IgG2a antibody production and increased splenocyte IFN-γ production, whereas
no IL-4 was detected. After a lethal challenge with the highly virulent T. gondii RH strain, a prolonged survival time in SAG1–GRA2-immunized mice was observed in comparison to control groups. Our data demonstrate
that SAG1–GRA2 triggered a protective response against toxoplasmosis. Therefore, SAG1–GRA2 protein might be a good candidate
for the further development of a multiantigenic vaccine. 相似文献
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Non-ribosomal peptide synthetases, polyketides and fatty acid synthetases have a modular organisation of multi-enzymatic activities. In all of them, the acyl or peptidyl carrier proteins have 4'-phosphopantetheine (P-pant) as an essential prosthetic group. This is added by 4'-phosphopantetheinyl transferases (PPTases) that derive the P-pant group from coenzyme A. While many PPTases of varying specificity have now been isolated from a number of bacteria, a filamentous fungal PPTase has yet to be characterised. Through database searching of the Aspergillus fumigatus genome sequence against Sfp from Bacillus subtilis, we identified a unique sequence which appears to encode a PPTase, as deduced from conserved residues considered important in PPTases. The PPTase candidate was used to search the NCBI data base and an unexpected homologue in A. nidulans was identified as npgA. Mutations in this gene (cfwA/ npgA) were identified previously as leading to defects in growth and pigmentation. To test whether the temperature-sensitive cfwA2 mutation impairs penicillin biosynthesis, which is dependent on the delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase, bioassays with B. calidolactis were set up at permissive and non-permissive temperatures. The cfwA2 mutant did not produce penicillin at the non-permissive temperature. Since no other PPTase homologue has been detected in the A. fumigatus genome to date, the data suggest that a single enzyme may be able to transfer the cofactor to a broad range of enzymes with acyl or peptidyl carrier protein domains. 相似文献
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Silva-Lopez RE Morgado-Díaz JA Alves CR Côrte-Real S Giovanni-De-Simone S 《Parasitology research》2004,93(4):328-331
Extracellular proteolytic activity was detected in a Leishmania (L.) amazonensis culture supernatant and a 56-kDa protein was purified using (NH4)2SO4 precipitation followed by affinity chromatography on aprotinin–agarose. A rabbit serum obtained against the 56-kDa extracellular serine protease was used in order to analyze its location in L. (L.) amazonensis parasites. Immunocytochemistry studies revealed that the enzyme is mainly found in the flagellar pocket and cytoplasmic vesicles of promastigote forms, whereas in amastigotes, it is located in electron-dense structures resembling megasomes. These results indicate that the 56-kDa serine protease is released into the extracellular environment through the flagellar pocket; and its intracellular location suggests either a correlated enzymatic activity or intracellular trafficking. 相似文献
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We have cloned a cDNA encoding Toxoplasma gondii pyruvate kinase and obtained the full-length recombinant enzyme with a calculated molecular mass of 57.5 kDa. The predicted amino acid sequence of T. gondii pyruvate kinase exhibited a highest identity (63%) to that of Eimeria tenella pyruvate kinase and a lower identity of less than 25% to the pyruvate kinases from other organisms. Southern blot analysis indicated that the pyruvate kinase gene existed as a single copy in the T. gondii tachyzoite. The active recombinant enzyme contained four subunits and produced a strongly sigmoid saturation curve with phosphoenolpyruvate as the variable substrate. Fructose 1,6-diphosphate, a general activating factor of pyruvate kinase in most species, did not affect the enzyme activity. However, glucose 6-phosphate radically activated the enzyme. Fructose 2,6-diphosphate suppressed the reaction velocity at a higher concentration of phosphoenolpyruvate. These properties indicate that pyruvate kinase activity in T. gondii is regulated by unusual phosphorylated sugars. 相似文献
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During routine serological survey, eight patients (5 pregnant women, 3 grafted patients) were positive for Toxoplasma gondii-specific IgM by enzyme-linked immunoassay but negative by a simultaneously performed immunosorbent agglutination assay. No clinical or biological symptoms of toxoplasmosis were observed later, despite the absence of treatment. Only one IgM-reactive band, which corresponded to the low-molecular-weight antigen of Toxoplasma gondii, was observed by Western blotting of these patients' sera. Dot blotting of lipid extracts of Toxoplasma gondii demonstrated that this reactivity was directed against sphingolipids or ceramides. This IgM positivity, which is unrelated to acute toxoplasmosis, raises strong concerns about the possibility of misleading results of this test in the diagnosis of toxoplasmosis in humans. 相似文献
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Protective immunity against<Emphasis Type="Italic"> Toxoplasma gondii</Emphasis> in mice induced by a chimeric protein rSAG1/2 总被引:5,自引:0,他引:5
The aim of this study was to test the protective immunity against Toxoplasma gondii in mice induced by a chimeric protein rSAG1/2. The PCR-amplified SAG2 fragment (558 bp) digested with the restriction enzyme XhoI was inserted into the XhoI site of plasmid pGEX-6p-1, termed pGexSAG2. The PCR-amplified SAG1 fragment (1,008 bp) digested with restriction enzymes EcoRI and XhoI was cloned into the EcoRI/XhoI sites of a separate plasmid pGEX-6p-1, termed pGexSAG1. The SAG2 fragment (HindIII/HindIII) excised from pGexSAG2 was inserted into the HindIII site of pGexSAG1 and a chimeric vector constructed, pGexSAG1/2. The fusion proteins GST-SAG1/2, GST-SAG1 and GST-SAG2 were expressed in BL21 Star (DE3) Escherichia coli and purified by GSTrap FF columns. After removing the GST tag, the recombinant proteins rSAG1/2, rSAG1 and rSAG2 were independently collected and injected into different groups of mice to evaluate their protective capability. The highest proliferation of splenocytes stimulated with tachyzoite sonicate antigen (TsoAg) was observed in BALB/c mice which had received two intraperitoneal injections of rSAG1/2. Maximum production of IFN- was also found in the culture supernatants of TsoAg-stimulated splenocytes from rSAG1/2-immunized mice. Finally, 73% (11/15) of mice immunized with rSAG1/2 survived at least 28 days after a lethal challenge of 1×103 live tachyzoites which killed all non-immunized mice within 10 days. Moderate survival rates were observed in mice immunized with either rSAG1 (60%) or rSAG2 (53%). These results show that the chimeric protein rSAG1/2 can elicit a Th1-associated protection against T. gondii infections in mice. 相似文献
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M. Nourollahpour Shiadeh A. Rostami B. D. Pearce M. Gholipourmalekabadi D. J. Newport M. Danesh S. Mehravar S. J. Seyyedtabaei 《European journal of clinical microbiology & infectious diseases》2016,35(11):1829-1835
Previous studies have demonstrated that latent toxoplasmosis is associated with neuropsychiatric disorders. We evaluated the correlation between Toxoplasma gondii infection and prenatal depression. In this case–control study, we enrolled 116 depressed pregnant women and 244 healthy controls. The Edinburgh Postpartum Depression Scale (EPDS) was used to evaluate the depression symptom severity in study participants. All participants were screened for the anti-Toxoplasma IgG by enzyme-linked immunosorbent assay. Seroprevalence of T. gondii did not significantly differ between the depressed pregnant women and healthy controls (OR?=?1.4; 95 % CI?=?0.9–2.19; P?=?0.142). T. gondii IgG titer was significantly higher in depressed women (18.6?±?10.9 IUs) than those in the control group (13.6?±?8.1 IUs) (z?= ?5.36, P?<?0.001). The T. gondii–positive depressed women showed a positive correlation of T. gondii IgG titer with the EPDS scores (r?=?0.52; P?<?0.01). The mean EPDS score was also significantly higher in the T. gondii–positive depressed women (20.7?±?2.7) compared with the controls (18.36?±?2.7) (P?<?0.001). The results obtained from the current study revealed that T. gondii infection might affect susceptibility to depression and severity of depressive symptoms in pregnant women, particularly in those patients who have high antibody titers. Further study is required to fully elucidate the characteristics and mechanisms of this association. 相似文献
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A. Lass H. Pietkiewicz E. Modzelewska A. Dumètre B. Szostakowska P. Myjak 《European journal of clinical microbiology & infectious diseases》2009,28(6):599-605
Infections caused by Toxoplasma gondii are prevalent in humans and animals throughout the world. So far, there is no sufficient information concerning T. gondii oocysts prevalence in the environment, especially in soil. Therefore, the aim of this study was to estimate occurrence of
T. gondii oocysts in soil and determine the genotype of detected parasites. A total of 101 soil samples were taken from different sites
(sand-pits, “farming ground”, areas around rubbish dumps) located in the Tri-City (Poland). Oocysts were recovered using the
flotation method. Then, PCR reactions targeting the B1 gene were performed for specific T. gondii detection. The positive samples were further confirmed by PCR amplification of a repetitive element (REP) sequence [GenBank
accession number AF146527]. Toxoplasma DNA was found in 18 samples. Among them, seven samples were successfully genotyped at the SAG2 locus. They were classified
as SAG2 type I (5 samples) and SAG2 type II (2 samples). This is one of the first investigations describing T. gondii oocyst detection in environmental soil samples with rapid molecular detection methods and genotyping. The results of our
findings showed that soil contaminated with T. gondii oocysts may play a role in the epidemiology of human toxoplasmosis in Poland. 相似文献
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Hoegger PJ Navarro-González M Kilaru S Hoffmann M Westbrook ED Kües U 《Current genetics》2004,45(1):9-18
In this study, we isolated and sequenced eight non-allelic laccase genes from Coprinopsis cinerea (Coprinus cinereus) homokaryon AmutBmut. These eight genes represent the largest laccase gene family identified so far in a single haploid fungal genome. We analyzed the phylogenetic relationships between these genes by intron positions, amino acid sequence conservation and similarities in promoter sequences. All deduced protein products have the laccase signature sequences L1–L4, the typical conserved cysteine and the ten histidine residues which are ligands in the two laccase copper-binding centers, T1 and T2/T3. Proteins Lcc2 and Lcc3 of Coprinopsis cinerea are most similar to the acidic, membrane-associated laccase CLAC2 from Coprinellus congregatus implicated in neutralization of acidic medium. All other laccases from the saprophyte Coprinopsis cinerea, including the well described enzyme Lcc1, form a cluster separate from these three enzymes and from various laccases of wood-rotting and plant-pathogenic basidiomycetes.Communicated by U. Kück 相似文献