Giardia lamblia: isoenzyme analysis of 19 axenic strains isolated from symptomatic and asymptomatic patients in Mexico

Axenically grown Giardia lamblia trophozoites treated with low concentrations of the benzimidazole carbamates albendazole and mebendazole detach from glass culture tubes and lose viability. Scanning electron microscopic observations revealed that these drugs produce grotesque modifications of the cell shape of the parasite and disassembly of the adhesive disc. Transmission electron microscopy showed several stages of the fragmentation of adhesive discs with dispersion of microtubules and microribbons in the cytoplasm. Flagella appeared undamaged. In drug-treated trophozoites electron-dense precipitates were selectively deposited on microtubules and microribbons. The results indicate that the antigiardial effect of benzimidazoles is the result of binding to microtubules and subsequent alterations of the cytoskeleton. The electron microscopic observations also suggest that the drugs may bind to microribbon components of the adhesive disc, possibly giardin proteins.

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“…Parasites. Giardia lamblia trophozoites strains IMSS:049 1 : 1 [2] and Portland-1 were cultured for 48 h at 36" C in TYIS.33 medium…”

Section: Methodsmentioning

confidence: 99%

Giardia lamblia: Ultrastructural Study of the In Vitro Effect of Benzimidazoles

Chávez¹,

Cedillo‐Rivera²,

Martı́nez-Palomo³

1992

The Journal of Protozoology

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“…These studies resulted in the description of three groups; group 3 was so different from groups 1 and 2 that the suggestion of a separate species designation was made. Subsequently, a number of other molecular classification studies have been performed using zymodeme analysis (2,16,47,212,214,234,277,316) and restriction fragment length polymorphism analysis (65, 85-87, 90, 137). Pulsed-field gel electrophoresis (PFGE) chromosome patterns have also been studied (7,42,143,167,291) but are of limited value for classification because of the frequent occurrence of chromosome rearrangements (4,179).…”

Section: Genotypes Of G Lambliamentioning

confidence: 99%

Biology ofGiardia lamblia

2001

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Giardia lamblia is a common cause of diarrhea in humans and other mammals throughout the world. It can be distinguished from other Giardia species by light or electron microscopy. The two major genotypes of G. lamblia that infect humans are so different genetically and biologically that they may warrant separate species or subspecies designations. Trophozoites have nuclei and a well-developed cytoskeleton but lack mitochondria, peroxisomes, and the components of oxidative phosphorylation. They have an endomembrane system with at least some characteristics of the Golgi complex and encoplasmic reticulum, which becomes more extensive in encysting organisms. The primitive nature of the organelles and metabolism, as well as small-subunit rRNA phylogeny, has led to the proposal that Giardia spp. are among the most primitive eukaryotes. G. lamblia probably has a ploidy of 4 and a genome size of approximately 10 to 12 Mb divided among five chromosomes. Most genes have short 5′ and 3′ untranslated regions and promoter regions that are near the initiation codon. Trophozoites exhibit antigenic variation of an extensive repertoire of cysteine-rich variant-specific surface proteins. Expression is allele specific, and changes in expression from one vsp gene to another have not been associated with sequence alterations or gene rearrangements. The Giardia genome project promises to greatly increase our understanding of this interesting and enigmatic organism

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“…Trophozoites obtained from the well-established G. lamblia isolate cultures listed in Table 1 were used for isoenzyme and RAPD analysis. The isoenzyme electrophoretic patterns of all G. lamblia isolates were obtained for ten dierent enzymes by thin-layer starch-gel electrophoresis (Cedillo-Rivera et al 1989;Meloni et al 1992). Samples containing 10±40 lg protein (trophozoite lysate), were separated by starch-gel electrophoresis at 4±6 V/cm 2 for 8±10 h. For RAPD analysis the parasites (10 8 trophozoites/ml) were lysed in 1 ml lysis buer [0.1 M TRIS-HCl (pH 8.0); 0.2 M NaCl; 100 mM ethylenediaminetetraacetic acid (EDTA, pH 8.0); 1x sodium dodecyl sulfate (SDS); and proteinase K at 0.2 mg/ml] and incubated at 37°C for 2 h. The DNA was extracted with phenol and chloroform and precipitated with ethanol.…”

mentioning

confidence: 99%

Characterization of Giardia lamblia groups A and B from North India by isoenzyme and random amplified polymorphic DNA analysis

Paintlia

Mahajan

Chakraborti

et al. 1999

Parasitology Research

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Giardia lamblia (syn. G. intestinalis) infection in young adults leads to acute/chronic diarrhea in some individuals and is asymptomatic in others. Recently, G. lamblia strains have been characterized as group A (symptomatic) and group B (asymptomatic or control) by advanced isoenzyme and molecular biology studies. In the present brief pilot study, ten G. lamblia isolates obtained from five symptomatic (group A) and five asymptomatic (group B) persons were characterized by isoenzyme and random amplified polymorphic DNA (RAPD) analysis. Isoenzyme analysis demonstrated remarkable homogeneity in seven enzyme patterns, the exception, being that of phosphoglucomutase, for which two zymodemes (I and III) were observed. In contrast, RAPD analysis showed homogeneity for eight primers; exceptions were two primers, A02 and B05, which separated group A G. lamblia isolates into two rapdemes (A(R1) and A(R2)) and group B G. lamblia isolates into four rapdemes (B(R1), B(R2), B(R3) and B(R4)). Further phenetic analysis showed average genetic distances of 0.105 within group A and 0.121 within group B G. lamblia isolates according to Jaccord's distance scale, which suggests that both lineages appear to consist of a range of variants with no significant (P < 0.05) genetic diversity. The two techniques demonstrated a positive association with regard to differentiation between group A and group B G. lamblia isolates. These very preliminary results indicate that RAPD analysis could be a potentially useful substitute for isoenzyme analysis.

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Giardia lamblia: isoenzyme analysis of 19 axenic strains isolated from symptomatic and asymptomatic patients in Mexico

Cited by 25 publications

References 11 publications

Giardia lamblia: Ultrastructural Study of the In Vitro Effect of Benzimidazoles

Giardia lamblia: Ultrastructural Study of the In Vitro Effect of Benzimidazoles

Biology ofGiardia lamblia

Characterization of Giardia lamblia groups A and B from North India by isoenzyme and random amplified polymorphic DNA analysis

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