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1.
Epidemiol Infect ; 142(4): 706-13, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23734968

RESUMO

SUMMARY Serum samples collected during the National Health and Nutrition survey (ENSANUT 2006) were obtained from subjects aged 1-95 years (January-October 2010) and analysed to assess the seroprevalence of Bordetella pertussis (BP) in Mexico. Subjects' gender, age, geographical region and socioeconomic status were extracted from the survey and compiled into a subset database. A total of 3344 subjects (median age 29 years, range 1-95 years) were included in the analysis. Overall, BP seroprevalence was 47.4%. BP seroprevalence was significantly higher in males (53.4%, P = 0.0007) and highest in children (59.3%) decreasing with advancing age (P = 0.0008). BP seroprevalence was not significantly different between regions (P = 0.1918) and between subjects of socioeconomic status (P = 0.0808). Women, adolescents and young adults were identified as potential sources of infection to infants. Booster vaccination for adolescents and primary contacts (including mothers) for newborns and infants may provide an important public health intervention to reduce the disease burden.


Assuntos
Coqueluche/epidemiologia , Coqueluche/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antibacterianos/sangue , Bordetella pertussis/imunologia , Distribuição de Qui-Quadrado , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Vacina contra Coqueluche , Estudos Soroepidemiológicos , Coqueluche/microbiologia , Coqueluche/prevenção & controle , Adulto Jovem
2.
Vaccine ; 39(40): 5839-5844, 2021 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-34465476

RESUMO

BACKGROUND: Low vaccination rates and under-detection of pertussis infections in adolescents and young adults have an impact on the transmission of pertussis to infants. In this study, the proportion of adolescents and young adults with IgG antibodies against B. pertussis antigens, representing recent infection or vaccination, was estimated in a population-based probabilistic survey in Mexico. METHODS: Sera and data from 1,581 subjects, including 1,102 adolescents and 479 young adults (10-19 and 20-25 years old, respectively) randomly selected from Mexico's 2012 National Health and Nutrition Survey, were analyzed. IgG antibodies against pertussis toxin (PT) were measured with the CDC/FDA ELISA. A subset of 234 samples was additionally tested with Bp-IgG PT ELISA kit (EUROIMMUN AG, Lubeck, Germany). Threshold values from corresponding test kits were used to identify recent infection or vaccination. RESULTS: Overall anti-PT IgG seroprevalence was 3.9% (95% CI: 2.3-6.3); 3.1% (95% CI: 1.9-5.0) in adolescents, and 4.9% (95% CI: 2.2-11) in young adults. Seroprevalence did not significantly vary by sex, socioeconomic status, region or rural/urban location. Compared to the CDC/FDA ELISA, the EUROIMMUN test showed a 76% sensitivity and 88% specificity. The weighted estimates represent a considerable burden of recent infection in adolescents and young adults; however, most adolescents and adults were seronegative and, therefore, susceptible to pertussis infection. CONCLUSION: Since booster vaccination to B. pertussis after toddlerhood is not recommended in the Mexican national policy, anti-PT IgG seropositivity may be reasonably attributed to recent infection. Assessing pertussis seroprevalence requires careful consideration of the diagnostic test threshold interpretation and epidemiological model used.


Assuntos
Bordetella pertussis , Coqueluche , Adolescente , Humanos , Lactente , México/epidemiologia , Inquéritos Nutricionais , Estudos Soroepidemiológicos , Coqueluche/diagnóstico , Coqueluche/epidemiologia , Adulto Jovem
3.
J Exp Med ; 174(1): 179-91, 1991 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-1711561

RESUMO

Trypanosoma cruzi expresses a developmentally regulated neuraminidase (TCNA) implicated in parasite invasion of cells. We isolated full-length DNA clones encoding TCNA. Sequence analysis demonstrated an open reading frame coding for a polypeptide of 1,162 amino acids. In the N-terminus there is a cysteine-rich domain containing a stretch of 332 amino acids nearly 30% identical to the Clostridium perfringens neuraminidase, three repeat motifs highly conserved in bacterial and viral neuraminidases, and two segments with similarity to the YWTD repeats found in the low density lipoprotein (LDL) receptor and in other vertebrate and invertebrate proteins. This domain is connected by a structure characteristic of type III modules of fibronectin to a long terminal repeat (LTR) consisting of 44 full length copies of twelve amino acids rich (75%) in serine, threonine, and proline. LTR is unusual in that it contains at least 117 potential phosphorylation sites. At the extreme C-terminus is a hydrophobic segment of 35 amino acids, which could mediate anchorage of TCNA to membranes via a glycosylphosphatidylinositol linkage. This is the first time a protozoan protein has been found to contain a YWTD repeat and a fibronectin type III module. The domain structure of TCNA suggests that the enzyme may have functions additional to its catalytic activity such as in protein-protein interaction, which could play a role in T. cruzi binding to host cells.


Assuntos
Clostridium perfringens/genética , Fibronectinas/genética , Neuraminidase/genética , Receptores de LDL/genética , Trypanosoma cruzi/genética , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais , Sequência de Bases , Clonagem Molecular , Clostridium perfringens/enzimologia , Fator de Crescimento Epidérmico/genética , Biblioteca Gênica , Humanos , Cinética , Dados de Sequência Molecular , Neuraminidase/isolamento & purificação , Neuraminidase/metabolismo , Conformação Proteica , RNA/genética , RNA/isolamento & purificação , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Sequências Repetitivas de Ácido Nucleico , Mapeamento por Restrição , Homologia de Sequência do Ácido Nucleico , Trypanosoma cruzi/enzimologia , Células Vero
4.
An Pediatr (Barc) ; 68(2): 128-35, 2008 Feb.
Artigo em Espanhol | MEDLINE | ID: mdl-18341878

RESUMO

INTRODUCTION: Rotavirus (RV) gastroenteritis (GE) causes a significant health and economic burden in Panama. The main objective of this study is to estimate the healthcare costs and the cost-effectiveness of vaccination in Panama from the societal perspective. METHODS: An economic model was constructed, using published epidemiological data, country-specific cost estimates, and vaccine efficacy data. The main outcome measures were disease burden, economic burden and the incremental cost-effectiveness ratio (US$/DALY and US$/life saved) of vaccination. RESULTS: In Panama, among children during the first five years of life, it is estimated that due to RV GE, 283 per 1,000 have a clinic visit, 24 per 1,000 are hospitalized, and 0.53 per 1,000 die. For every 1,000 children born, RV infection results in US$16,463 in total costs during their first five years of life. An estimated US$862,388 may be spent annually on treatment of outpatient and hospitalized cases in Panama. Vaccination would prevent 65% of the associated deaths, 68% of hospitalizations, 69% of outpatient visits and 65% of associated DALY (Disability Adjusted Life Years). From the societal perspective, RV vaccination produces a cost-effectiveness ratio of US$487 per DALY when the price of the vaccine is US$7.50 per dose. CONCLUSIONS: Vaccination can effectively reduce the disease burden and healthcare costs of RV GE in Panama.


Assuntos
Infecções por Rotavirus/economia , Infecções por Rotavirus/prevenção & controle , Vacinas contra Rotavirus/economia , Pré-Escolar , Análise Custo-Benefício , Humanos , Modelos Econômicos , Panamá
5.
J Clin Invest ; 94(6): 2283-8, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7989583

RESUMO

Giardia lamblia, a cause of diarrheal disease throughout the world, is a protozoan parasite that thrives in the small intestine. It is shown here that wheat germ agglutinin (WGA), a naturally occurring lectin widely consumed in normal human diets, reversibly inhibits the growth of G. lamblia trophozoites in vitro, and reduces infection by G. muris in the adult mouse model of giardiasis. The inhibitory effect was dose related, not associated with cytotoxicity and reversed by N-acetyl-D-glucosamine in accordance with the known specificity of the lectin and in agreement with the presence of GlcNAc residues on the surface membrane of G. lamblia trophozoites. Cell cycle analysis revealed that parasites grown in the presence of WGA are arrested in the G2/M phase, providing an explanation for the lectin-induced inhibition of cell proliferation. Comparison of electrophoretic profiles by lectin blot analysis revealed both glycoprotein induction and suppression in growth-arrested organisms. Our findings raise the possibility that blocking trophozoite growth with naturally occurring dietary lectins may influence the course of giardiasis. In addition, the study of cell cycle arrest by WGA may provide a model to study the regulation of cell division in lower eukaryotes.


Assuntos
Proteínas Alimentares/uso terapêutico , Giardíase/tratamento farmacológico , Receptores Mitogênicos/metabolismo , Aglutininas do Germe de Trigo/uso terapêutico , Animais , Adesão Celular/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Giardia/efeitos dos fármacos , Giardia/crescimento & desenvolvimento , Giardia lamblia/efeitos dos fármacos , Giardia lamblia/crescimento & desenvolvimento , Glicoproteínas/biossíntese , Lectinas , Camundongos , Proteínas de Protozoários/biossíntese , Ratos
6.
J Ethnopharmacol ; 103(3): 461-7, 2006 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-16266794

RESUMO

A new prenylated salicylic acid derivative, 3-farnesyl-2-hydroxy benzoic acid (1), was isolated from the leaves of Piper multiplinervium C. DC. (Piperaceae). It showed anti-Helicobacter pylori activity (MIC 37.5 microg/ml) and antimicrobial activity at MICs between 2.5 and 5 microg/ml against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Mycobacterium smegmatis, Pseudomonas aeruginosa and Candida albicans. Its structure was elucidated by means of MS, 1H and 13C NMR. The ethnomedical claim of Piper multiplinervium to treat stomach aches by the Kuna Indians of Panama may be justified by anti-Helicobacter pylori activity of its MeOH extract.


Assuntos
Anti-Infecciosos/farmacologia , Farneseno Álcool/análogos & derivados , Helicobacter pylori/efeitos dos fármacos , Hidroxibenzoatos/farmacologia , Piper/química , Anti-Infecciosos/isolamento & purificação , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Farneseno Álcool/farmacologia , Helicobacter pylori/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Estrutura Molecular , Panamá , Folhas de Planta , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
7.
Rev Sci Tech ; 24(3): 1067-75, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16642775

RESUMO

In addition to causing large losses to the cattle industry, Mycobacterium bovis, the causative agent for bovine tuberculosis, is a serious public health issue because it can potentially infect humans. Diagnosis based on isolation and identification of the bacillus is tedious and may take weeks. The diagnosis of M. bovis by polymerase chain reaction (PCR), using species-specific primers, is fast, highly sensitive and of great value in epidemiological studies. In this study, deoxyribonucleic acid (DNA) was extracted from 60 nasal mucus samples collected from three different farms, all located in an area where M. bovis is endemic. Two farms tested negative for an antibody response to the M. tuberculosis purified protein derivative (PPD) antigen, whereas the other farm gave a positive result. The amplified fragment of DNA was 460 base pairs with a sequence similar to that previously reported. Only 5% of the samples from the third farm tested positive for the presence of antibodies against PPD, whereas 65% of samples (from all three farms) gave a positive result when PCR was used. Thus, the authors suggest the use of the PCR species-specific primers test to support the programme against bovine tuberculosis in Panama.


Assuntos
DNA Bacteriano/análise , Mycobacterium bovis/isolamento & purificação , Reação em Cadeia da Polimerase/veterinária , Tuberculose Bovina/diagnóstico , Animais , Bovinos , Epidemiologia Molecular , Mycobacterium bovis/classificação , Mycobacterium bovis/genética , Panamá/epidemiologia , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/normas , Sensibilidade e Especificidade , Especificidade da Espécie , Tuberculose Bovina/epidemiologia
8.
J Immunol Methods ; 167(1-2): 161-71, 1994 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-7508475

RESUMO

Pneumocystis carinii, an extracellular parasite thriving in the lungs of immunosuppressed mammals, is a major cause of death in AIDS patients in the USA. As a prelude to growth, the parasite adheres mostly to type I pneumocytes lining the alveolar spaces. The mechanism of adherence remains unknown, largely because of difficulties in isolating type I pneumocytes and maintaining them in vitro. As a first step to understand P. carinii adherence to its natural substrate, we developed an in situ method to directly study parasite binding to lung alveolar cells. We used formaldehyde-fixed paraffin-embedded sections of normal rat lung as substrate for adhesion. As in its binding to the lungs in vivo, P. carinii adhered preferentially to type I pneumocytes. Adherence was saturable, time and dose dependent, and selectively blocked by glycoconjugates, in particular bovine submaxillary mucin, fetuin, and asialofetuin, suggesting that it may be mediated by a lectin type of interaction. Further, IgG of rats with P. carinii pneumonia inhibited adherence, suggesting that it may react with parasite ligands involved in the recognition of type I cell receptors. Our results demonstrate the usefulness of the in situ model for studying the mechanisms of P. carinii adherence to alveolar cells. In addition, this method may be valuable for identifying neutralizing antibodies and drugs potentially useful for controlling the infection in vivo.


Assuntos
Adesão Celular/fisiologia , Modelos Biológicos , Pneumocystis/fisiologia , Alvéolos Pulmonares/fisiologia , Animais , Anticorpos Antifúngicos/farmacologia , Carboidratos/farmacologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Fluoresceína-5-Isotiocianato , Glicoproteínas/farmacologia , Técnicas de Preparação Histocitológica , Humanos , Lectinas , Pneumocystis/citologia , Pneumocystis/imunologia , Alvéolos Pulmonares/citologia , Ratos , Coloração e Rotulagem
9.
Mol Biochem Parasitol ; 65(1): 73-83, 1994 May.
Artigo em Inglês | MEDLINE | ID: mdl-7935630

RESUMO

Trypanosoma cruzi attaches and invades a large variety of mammalian cells by receptor-mediated interactions, one of them involving the binding of parasite trans-sialidase to host sialyl receptors. Three proteoglycan-deficient mutants of Chinese hamster ovary (CHO) cells were used to probe the role of host heparin and heparan sulfate glycosaminoglycans (GAG) in T. cruzi invasion. All three mutants supported adhesion and infection to a much lower extent than the parental CHO cells. One of the mutants, pgsD-677, did not express heparan sulfate while containing three- to four-fold excess chondroitin sulfate, yet the cell line was a poor substrate for T. cruzi adhesion. Proteoglycan-deficient cells obtained by inhibiting GAG synthesis in parental cells with p-nitrophenyl-beta-D-xyloside, were also poor hosts for T. cruzi invasion. Furthermore, digestion of parental cells with heparinase and heparitinase, two lyases that specifically depolymerize heparin and heparan sulfate, reduced the potential of the cells to support T. cruzi adhesion and growth. Lyases that digested chondroitin sulfate and other GAGs did not affect T. cruzi invasion. These results suggest that heparin/heparan sulfate epitopes are receptors for T. cruzi invasion. The corresponding counter-receptor on T. cruzi appears to be penetrin, a heparin-binding protein that promotes trypanosome penetration into cells. Purified penetrin caused agglutination of red blood cells, and the hemagglutination was exquisitely sensitive to heparin and heparan sulfate. However, sialic acid and sialyl compounds did not inhibit penetrin-induced hemagglutination. Recombinant penetrin competitively inhibited T. cruzi invasion of proteoglycan-containing parental cells, but not of proteoglycan-deficient mutants nor of heparitinase-treated cells. Furthermore, consistent with the sugar specificity of penetrin as a hemagglutinin, recombinant penetrin competed for trypanosome invasion of a CHO cell mutant (Lec2) that expresses heparan sulfate but not sialyl residues. Given that the release of sialic acid from the proteoglycan-deficient mutants further reduced T. cruzi invasion, as did the removal of heparan sulfate from the Lec2 mutant, and given that penetrin does not bind to sialic acid with high affinity, the results indicate that the penetrin-heparan sulfate pathway for T. cruzi invasion is distinct from the trans-sialidase-sialic acid route.


Assuntos
Heparitina Sulfato/fisiologia , Proteínas de Protozoários/fisiologia , Receptores de Superfície Celular/fisiologia , Trypanosoma cruzi/fisiologia , Animais , Células CHO , Adesão Celular/fisiologia , Cricetinae , Glicoproteínas/farmacologia , Glicoproteínas/fisiologia , Glicosaminoglicanos/genética , Glicosaminoglicanos/fisiologia , Hemaglutinação/fisiologia , Heparina/genética , Heparina/fisiologia , Heparitina Sulfato/genética , Mutação , Neuraminidase/farmacologia , Neuraminidase/fisiologia , Receptores de Superfície Celular/genética , Ácidos Siálicos/fisiologia , Trypanosoma cruzi/patogenicidade
10.
Mol Biochem Parasitol ; 59(2): 243-52, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8341323

RESUMO

Trypanosoma cruzi attaches and invades a large variety of mammalian cells. The nature of the cell receptors and of the corresponding parasite counter-receptors that mediate T. cruzi-host cell interaction are not known. Three sialic acid-deficient mutants of Chinese hamster ovary (CHO) cells were used to probe the role of host sialyl residues in T. cruzi infection. All three mutants supported adhesion and infection to a much lower extent than the parental CHO cells. One of the mutants, Lec2, contains sugar chains terminating in non-reducing beta Gal residues, which are acceptors for sialylation by the T. cruzi trans-sialidase. Re-sialylation of Lec2 cells restored T. cruzi adhesion and invasion to about the same extent as wild-type cells. Digestion of wild-type cells with bacterial sialidase reduced T. cruzi interaction but after re-sialylation, the cells were almost as good as control, naturally sialylated parental cells. These results suggest that T. cruzi recognizes sialyl residues on the surface of host cells during invasion. On the other hand, affinity-purified trans-sialidase blocked T. cruzi adherence and invasion of sialylated cells, and had no effect on parasite interaction with sialic acid-deficient Lec2 mutant. Furthermore, 2,3-sialyllactose, a substrate for the trans-sialidase, competitively inhibited T. cruzi invasion of sialylated parental K1 cells, but 2,6-sialyllactose, which does not react with the trans-sialidase, was without effect, as were other sugars that do not contain alpha 2,3 sialyl residues. These results suggest that the trans-sialidase functions as a counter-receptor for trypomastigote binding to alpha 2,3-sialyl receptors on host cells as a prelude to T. cruzi invasion.


Assuntos
Adesão Celular , Glicoproteínas , Neuraminidase/metabolismo , Ácidos Siálicos/fisiologia , Trypanosoma cruzi/fisiologia , Sequência de Aminoácidos , Animais , Células CHO , Adesão Celular/efeitos dos fármacos , Cromatografia de Afinidade , Cricetinae , Eletroforese em Gel de Poliacrilamida , Cinética , Dados de Sequência Molecular , Ácido N-Acetilneuramínico , Neuraminidase/isolamento & purificação , Neuraminidase/farmacologia , Oligopeptídeos , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/enzimologia , Células Vero
11.
Mol Biochem Parasitol ; 52(1): 85-96, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1378212

RESUMO

We have previously shown that a polyclonal (rabbit anti-TCNA) and a mouse monoclonal antibody (TCN-2) against the neuraminidase of Trypanosoma cruzi (TCNA) inhibit enzyme activity, immunoprecipitate active enzyme, enhance in vitro infection, and identify a subpopulation of extracellular trypomastigotes. We now report on the identification of a synthetic peptide that contains the epitope recognized by these antibodies. The synthetic peptide (TR) is a dodecamer (D-S-S-A-H-G-T-P-S-T-P-A) deduced from the DNA sequence of the long tandem repeat (LTR) domain present in the TCNA carboxyterminus. By ELISA, rabbit anti-TCNA bound to TR coupled to ovalbumin, and the binding was inhibited by soluble TR but not by BR (Y-S-V-D-D-G-E-T-W-E), a peptide derived from the N-terminal domain of the enzyme. TCN-2 recognized TR, and this reaction as well as TCN-2 binding to endogenous TCNA could be inhibited by soluble TR but not by BR. These results indicate that the rabbit anti-TCNA and TCN-2 react with the LTR region of TCNA. Antibodies to TR reacted by immunoblot with the TCNA of the Silvio X-10/4, MV-13 and Y-H6 strains, identifying the same molecular polymorphism previously observed with the rabbit anti-TCNA and TCN-2. Furthermore, anti-TR antibodies immunoprecipitated active enzyme and immunofluorescence analysis revealed that anti-TR and TCN-2 antibodies detected equally well the differential expression of their epitopes in intra- and extracellular trypomastigotes. Moreover, expression of TR and TCN-2 epitopes on the different stages of T. cruzi paralleled the stage-specificity of TCNA activity. TCN-2 prevented desialylation by TCNA of intact cells but not of soluble glycoconjugates, indicating that TCN-2 epitope is probably not associated with the enzyme catalytic site, in agreement with the predicted sequence of the TCNA gene. Finally, analysis of the humoral response of a Chagasic patient to different areas of the TCNA molecule indicated that the antibody response is predominantly against TR suggesting that the tandem repeat is the immunodominant domain of TCNA.


Assuntos
Linfócitos B/imunologia , Epitopos/imunologia , Neuraminidase/imunologia , Trypanosoma cruzi/enzimologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Immunoblotting , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Neuraminidase/metabolismo , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/imunologia , Testes de Precipitina , Trypanosoma cruzi/imunologia , Células Vero
12.
Mol Biochem Parasitol ; 43(2): 151-65, 1990 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2128647

RESUMO

Previously, on the basis of lectin binding and glycosidase digestion assays, we have suggested that N-acetyl-D-glucosamine residues (GlcNAc) are major structural components of both trophozoites and in vivo cysts of the intestinal parasite Giardia lamblia. In this report we confirm that GlcNAc is present both in trophozoites and in vitro cysts as assessed by lectin binding and glycosidase digestion assays, galactosyltransferase labeling, immunochemical analysis using antibodies specific for GlcNAc and its beta 1-4 oligomers, and by gas chromatography/mass spectrometry (GC/MS). The results show that wheatgerm agglutinin (WGA) binds specifically to intact trophozoites and in vitro cysts as well as to SDS-PAGE separated proteins. WGA binding to the separated proteins was markedly reduced after their digestion with N-acetyl-beta-D-glucosaminidase, supporting the conclusion that WGA is reacting with terminal beta-linked GlcNAc residues. Labeling of trophozoites and cysts by 3H-exogalactosylation with galactosyltransferase further confirmed the presence of terminal GlcNAc in both surface and intracellular glycoproteins. The presence of GlcNAc is also supported by microfluorometric analysis using antibodies to (GlcNAc)1, (GlcNAc)2, and (GlcNAc)3, which revealed a sugar-inhibitable binding of the antibody to live trophozoites. Finally, the presence of GlcNAc in both cysts and trophozoites was unequivocally confirmed by GC/MS analysis of detergent-extracted membranes and of glycoproteins isolated by affinity chromatography on WGA-agarose. GC/MS analysis also revealed mannose (Man), N-acetyl-D-galactosamine (GalNAc), fucose (Fuc), galactose (Gal), glucose (Glc) and N-acetylneuraminic acid (NANA) to be present in cysts. All these sugars were also present in trophozoites, except for GalNAc. The glycoproteins isolated by WGA affinity chromatography were 5- to 40-fold enriched in GlcNAc, further supporting the conclusion that WGA reacts with GlcNAc in Giardia. In summary, the data presented here provide biological and chemical evidence for GlcNAc in both cysts and trophozoites of G. lamblia and are consistent with previously published results from this and other laboratories.


Assuntos
Acetilglucosamina/metabolismo , Giardia/metabolismo , Aglutininas do Germe de Trigo/metabolismo , Acetilglucosamina/análise , Animais , Bovinos , Colostro/enzimologia , Eletroforese em Gel de Poliacrilamida , Galactosiltransferases/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Giardia/análise , Giardia/crescimento & desenvolvimento , Imunoquímica
13.
Invest Ophthalmol Vis Sci ; 32(12): 3061-6, 1991 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1938282

RESUMO

Acanthamoeba species, a widely distributed group of free-living amoeba, can infect humans and spread hematogenously after direct interaction with the mucosal surfaces. The mechanism underlying Acanthamoeba damage to the target cell is unknown. The authors report that trophozoites and cysts of Acanthamoeba species exhibit a neuraminidase activity that is membrane associated and released into the culture medium at the start of the logarithmic phase of growth. The enzyme activity is optimal at pH 5 and at 25-30 degrees C. Live parasites release sialic acid from human cells. Therefore, the neuraminidase of Acanthamoeba species could be relevant in the colonization and damage of the sialic acid-rich corneal epithelium and in the alterations of glycolipids associated with meningoencephalitis.


Assuntos
Acanthamoeba/enzimologia , Neuraminidase/metabolismo , Acanthamoeba/crescimento & desenvolvimento , Animais , Membrana Celular/enzimologia , Meios de Cultura , Estabilidade Enzimática , Fluorometria , Neuraminidase/química , Neuraminidase/isolamento & purificação , Especificidade por Substrato
14.
Trans R Soc Trop Med Hyg ; 98(3): 148-51, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15024923

RESUMO

Skin biopsies stored in ethanol from 49 patients with suspected cutaneous leishmaniasis (CL) were tested in a real-time polymerase chain reaction (PCR) assay and compared with conventional diagnostic methods. With clinical diagnosis as the gold standard, PCR had a sensitivity of 96% (47/49) vs. 61% (30/49) for histopathology and 33% (16/49) for culture. In addition, DNA was extracted from 70 frozen smears of lesions from suspected cases of CL and tested with the same assay. In these samples, the PCR had a sensitivity of 61% (43/70) vs. 56% (39/70) for histopathology and 41% (29/70) for culture. In this study, real-time PCR offered a rapid diagnosis with an enhanced sensitivity over conventional methods. Although the yield of PCR diagnosis was lower when testing frozen smears, the assay still outperformed existing diagnostic modalities.


Assuntos
Leishmaniose Cutânea/diagnóstico , Reação em Cadeia da Polimerase/métodos , Adulto , Biópsia por Agulha/métodos , Biópsia por Agulha/normas , Criopreservação , Humanos , Reação em Cadeia da Polimerase/normas , Sensibilidade e Especificidade , Pele/patologia
16.
Trop Med Parasitol ; 43(3): 186-90, 1992 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1281927

RESUMO

Pneumocystitis carinii is known to adhere to pulmonary alveolar epithelial cells in vivo and to epithelial cell lines in vitro by a mechanism unknown at the molecular level. P. carinii is now found to adhere to rabbit and human red blood cells leading to rosette formation and hemagglutination. P. carinii erythrocyte-adherence was best inhibited by bovine submaxillary mucin and by a polysaccharide from the wall of group A Streptococcus, and to a lesser extent by Streptococcus group C polysaccharide, asialofetuin and fetuin. Among the mono- and oligosaccharides tested, only lactose inhibited hemagglutination. Other glycoconjugates and oligosaccharides tested were inactive. P. carinii also bound to purified glycoproteins coupled to Sepharose or adsorbed to plastic, and the binding was inhibited by soluble bovine submaxillary mucin. These results indicate that P. carinii has a novel surface lectin that may be important in adherence to lung alveolar epithelial cells.


Assuntos
Hemaglutinação , Lectinas/análise , Pneumocystis/química , Pneumonia por Pneumocystis/parasitologia , Animais , Assialoglicoproteínas/farmacologia , Adesão Celular/efeitos dos fármacos , Epitélio/parasitologia , Fetuínas , Imunofluorescência , Testes de Hemaglutinação , Histocitoquímica , Humanos , Masculino , Mucinas/farmacologia , Pneumocystis/efeitos dos fármacos , Pneumocystis/metabolismo , Polissacarídeos Bacterianos/farmacologia , Coelhos , Ratos , Ratos Sprague-Dawley , Formação de Roseta , Streptococcus pyogenes , alfa-Fetoproteínas/farmacologia
17.
Infect Agents Dis ; 1(3): 136-45, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1365537

RESUMO

Trypanosoma cruzi invades a variety of mammalian cells by receptor-ligand interactions. In this review two T. cruzi carbohydrate-binding proteins, neuraminidase/trans-sialidase and penetrin, are discussed as possibly playing a role in parasite entry into mammalian cells.


Assuntos
Neuraminidase/fisiologia , Trypanosoma cruzi/patogenicidade , Animais , Fibronectinas/fisiologia , Ácido N-Acetilneuramínico , Ácidos Siálicos/metabolismo
18.
Cell ; 67(2): 411-21, 1991 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-1655283

RESUMO

T. cruzi invades mammalian cells in various organs after migrating through the ECM. These activities appear to be mediated by a unique 60 kd protein exposed on the T. cruzi surface, which promotes selective adhesion of trypomastigotes to three ECM components: heparin, heparan sulfate, and collagen. The affinity-purified protein binds to host fibroblasts in a saturable and glycosaminoglycan- and collagen-inhibitable manner. When adsorbed to plastic, it promotes adhesion and spreading of fibroblasts, as does the recombinant protein expressed in E. coli. The endogenous protein, and reactive ECM proteins, are very effective in preventing T. cruzi invasion of culture cells. The recombinant protein localizes on the E. coli surface and induces the bacteria that express it to adhere to and penetrate nonphagocytic Vero cells in a proteoglycan- and collagen-inhibitable manner. Therefore, the protein, named penetrin, could play a critical role in T. cruzi binding to the ECM and to cells, and in host cell invasion.


Assuntos
Adesão Celular/fisiologia , Fibroblastos/parasitologia , Proteínas de Protozoários/metabolismo , Receptores de Superfície Celular/metabolismo , Trypanosoma cruzi/fisiologia , Animais , Cromatografia em Agarose , Colágeno/metabolismo , Colágeno/farmacologia , Eletroforese em Gel de Poliacrilamida , Escherichia coli/fisiologia , Matriz Extracelular/metabolismo , Matriz Extracelular/parasitologia , Fibroblastos/metabolismo , Fibroblastos/microbiologia , Glicosaminoglicanos/metabolismo , Glicosaminoglicanos/farmacologia , Heparina/metabolismo , Heparina/farmacologia , Heparitina Sulfato/metabolismo , Heparitina Sulfato/farmacologia , Microscopia Eletrônica , Proteoglicanas/metabolismo , Proteínas de Protozoários/isolamento & purificação , Receptores de Superfície Celular/isolamento & purificação , Proteínas Recombinantes/metabolismo , Trypanosoma cruzi/metabolismo , Células Vero
19.
J Biol Chem ; 274(3): 1267-76, 1999 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-9880495

RESUMO

Toxoplasma gondii is one of the most widespread parasites of humans and animals. The parasite has a remarkable ability to invade a broad range of cells within its mammalian hosts by mechanisms that are poorly understood at the molecular level. This broad host cell specificity suggests that adhesion should involve the recognition of ubiquitous surface-exposed host molecules or, alternatively, the presence of various parasite attachment molecules able to recognize different host cell receptors. We have discovered a sugar-binding activity (lectin) in tachyzoites of T. gondii that plays a role in vitro in erythrocyte agglutination and infection of human fibroblasts and epithelial cells. The ability to agglutinate erythrocytes can be reversed by a variety of soluble glycoconjugates, of which heparin, fucoidan, and dextran sulfate were the most effective. Interestingly, infectivity of tachyzoites for human foreskin fibroblasts, cells that are commonly used to grow T. gondii in vitro, was increased by low concentrations of the sulfated glycoconjugates that inhibited hemagglutination activity (i.e. dextran sulfate and fucoidan) whereas high concentrations inhibited parasite infection. Furthermore, inhibition of glycosaminoglycan biosynthesis and sulfation on the host cells reduced Toxoplasma infectivity. Finally, Toxoplasma tachyzoites showed a reduced ability to infect epithelial cell mutants deficient in the biosynthesis of surface proteoglycans. The probable identity of the hemagglutinin(s) was investigated by 1) direct binding of red blood cells to filter blots of Toxoplasma proteins separated by polyacrylamide gel electrophoresis, and 2) binding of metabolically labeled parasite proteins to fixed mammalian cells. Three parasite bands were thus identified as candidate adhesins. These results suggest that attachment of T. gondii to its target cell is mediated by parasite lectins and that sulfated sugars on the surface of host cells may function as a key parasite receptor.


Assuntos
Lectinas/isolamento & purificação , Lectinas/metabolismo , Polissacarídeos/metabolismo , Toxoplasma/patogenicidade , Animais , Western Blotting , Células CHO , Linhagem Celular , Cricetinae , Eritrócitos/metabolismo , Proteoglicanas de Heparan Sulfato/metabolismo , Humanos , Proteoglicanas/biossíntese , Coelhos , Sulfatos/metabolismo
20.
Infect Immun ; 63(3): 874-83, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7532628

RESUMO

The ability of the Lyme disease spirochete to attach to host components may contribute to its ability to infect diverse tissues. We present evidence that the Lyme disease spirochete expresses a lectin activity that promotes agglutination of erythrocytes and bacterial attachment to glycosaminoglycans. Among a diverse collection of 21 strains of Lyme disease spirochete, hemagglutinating activity was easily detected in all but 3 strains, and these three strains were noninfectious. The ability to agglutinate erythrocytes was associated with the ability of the spirochete to bind to the sulfated polysaccharide dextran sulfate and to mammalian cells. Soluble dextran sulfate was a potent inhibitor of both hemagglutination and attachment to mammalian cells, while dextran had no effect on either activity, suggesting that dextran sulfate may inhibit attachment by mimicking host cell glycosaminoglycans. Consistent with this, the spirochete bound to immobilized heparin, and soluble heparin inhibited bacterial adhesion to mammalian cells. The bacterium did not bind efficiently to Vero cells treated with heparinase or heparitinase or to mutant CHO cell lines that are deficient in proteoglycan synthesis. Sulfation of glycosaminoglycans was critical for efficient bacterial recognition, as Vero cells treated with an inhibitor of sulfation, or a mutant CHO cell line that produces undersulfated heparan sulfate, did not mediate maximal spirochetal binding. Binding of the spirochete to extracellular matrix also appeared to be dependent upon this attachment pathway. These findings suggest that a glycosaminoglycan-binding activity which can be detected by hemagglutination contributes to the attachment of the Lyme disease spirochete to host cells and matrix.


Assuntos
Aderência Bacteriana/fisiologia , Grupo Borrelia Burgdorferi/metabolismo , Borrelia burgdorferi , Proteoglicanas/metabolismo , Animais , Grupo Borrelia Burgdorferi/patogenicidade , Células CHO , Chlorocebus aethiops , Cricetinae , Sulfato de Dextrana/metabolismo , Matriz Extracelular/metabolismo , Testes de Hemaglutinação , Heparina/metabolismo , Heparitina Sulfato , Integrinas/metabolismo , Complexo Glicoproteico GPIIb-IIIa de Plaquetas , Proteoglicanas/biossíntese , Ésteres do Ácido Sulfúrico , Células Vero , Virulência
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