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1

Electron microscopy of Giardia lamblia cysts.  

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The flagellated protozoan Giardia lamblia is a recognized public health problem. Intestinal infection can result in acute or chronic diarrhea with associated symptoms in humans. As part of a study to evaluate removal of G. lamblia cysts from drinking water by the processes of coagulation and dual-media filtration, we developed a methodology by using 5.0-microns-porosity membrane filters to evaluate the filtration efficiency. We found that recovery rates of G. lamblia cysts by membrane filtrat...

1980-01-01

2

Improved In Vitro Excystation Procedure for Giardia lamblia Cysts  

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Giardia lamblia cysts obtained from human symptomatic and asymptomatic donors were excysted in vitro. Excystation averaged 87% for cysts from symptomatic donors and 70% for cysts from asymptomatic donors.

Rice, Eugene W.; Schaefer, Frank W.

1981-01-01

3

Immunofluorescence and morphology of Giardia lamblia cysts exposed to chlorine.  

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Giardia cyst-like objects detected by immunofluorescence in chlorinated water samples often cannot be positively identified by their morphological appearance. To determine the effect of chlorine on cyst immunofluorescence and morphology, Giardia lamblia cysts were exposed to chlorine for 48 h. The majority of cysts exposed to chlorine concentrations of 1 to 11 mg/liter at 5 and 15 degrees C lost their internal morphological characteristics necessary for identification, but most of them were s...

Sauch, J. F.; Berman, D.

1991-01-01

4

Comparison of Giardia lamblia and Giardia muris cyst inactivation by ozone.  

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Inactivation of Giardia lamblia and Giardia muris cysts was compared by using an ozone demand-free 0.05 M phosphate buffer in bench-scale batch reactors at 22 degrees C. Ozone was added to each trial from a concentrated stock solution for contact times of 2 and 5 min. The viability of the control and treated cysts was evaluated by using the C3H/HeN mouse and Mongolian gerbil models for G. muris and G. lamblia, respectively. The resistance of G. lamblia to ozone was not significantly different...

Finch, G. R.; Black, E. K.; Labatiuk, C. W.; Gyu?re?k, L.; Belosevic, M.

1993-01-01

5

Degradation of Giardia lamblia cysts in mixed human and swine wastes.  

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This study was conducted to determine the persistence of Giardia lamblia cysts in mixed septic tank effluent and swine manure slurry and to correlate fluorescein diacetate-propidium iodide staining of G. lamblia cysts with their morphology under low-voltage scanning electron microscopy. Under field conditions, G. lamblia cysts were degraded more rapidly in the mixed waste than in the control Dulbecco's phosphate-buffered saline (PBS). For total and viable cysts, the mixed waste had D values (...

Deng, M. Y.; Cliver, D. O.

1992-01-01

6

ENCYSTATION AND EXPRESSION OF CYST ANTIGENS BY 'GIARDIA LAMBLIA' IN VITRO  

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The cyst form of Giardia lamblia is responsible for transmission of giardiasis, a major waterborne intestinal disease. These studies demonstrate for the first time expression of cyst antigens and encystation of G. lamblia in vitro by both morphologic and immunologic criteria. The...

7

Immuno-PCR for detection of Giardia lamblia cysts in water.  

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Giardia lamblia cysts at low concentrations were detected in water samples using a highly sensitive immunological-PCR (IPCR) method. Magnetic gold particles were precoated with monoclonal anti-Giardia antibodies, and Giardia lamblia cysts ranging from 1 to 100 cysts were diluted in 500 microL of water. A biotinylated detection antibody bound to the G. lamblia cysts was then linked by a streptavidin bridge to biotinylated Giardia-reporter DNA. After extensive washing, reporter DNA was released by denaturation, transferred to PCR tubes, amplified, electrophoresed, and visualized. An optimized immuno-PCR method detected as little as five G. lamblia cysts. To further evaluate the specificity and the clinical application of this IPCR assay for G. lamblia cysts, Entamoeba histolytica and Cryptosporidium parvum were also collected and detected by IPCR. The data demonstrated that this monoclonal antibody-based IPCR method is particularly useful for analysis of environmental water samples in which the densities of G. lamblia cysts is very low, and provides a platform capable of rapid screening of samples from drinking water, wells, rivers, lakes, and recreational swimming pools for trace levels of G. lamblia cysts. PMID:24830167

Deng, Ming Jun; Ji, Xin Cheng; Xiao, Xi Zhi; Sun, Tao; Wu, Zhen Xing; Zheng, Xiao Long; Wang, Qun; Zhu, Lai Hua

2014-01-01

8

Development and testing of a filter system for isolation of Giardia lamblia cysts from water.  

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An inexpensive, practical, and reliable method for isolation of Giardia lamblia cysts from potable and environmental water has been developed from commercially available components. This system was successfully used to isolate cysts from well water associated with a family outbreak of giardiasis.

Hausler, W. J.; Davis, W. E.; Moyer, N. P.

1984-01-01

9

INACTIVATION OF GERBIL-CULTURED GIARDIA LAMBLIA CYSTS BY FREE CHLORINE  

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Giardia lamblia cysts were harvested from Mongolian gerbils and exposed to free chlorine in buffered water at pH 5, 7, and 9 at 15 degrees C. he contact times required to obtained a 2-log reduction in cyst survival (i.e., a 99% kill) were interpolated from survival curves generat...

10

A Novel Family of Cyst Proteins with Epidermal Growth Factor Repeats in Giardia lamblia  

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The biological goal of Giardia lamblia life cycle is differentiation into a cyst form (encystation) that can survive in the environment and infect a new host. Since cystic stages are key to transmission of parasites, this differentiation may be a target for interruption of the life cycle. Synthesis and assembly of the extracellular cyst wall are the major hallmarks of this important differentiation. During encystation, cyst wall structural proteins are coordinately synthesized and are mainly ...

Chiu, Pei-wei; Huang, Yu-chang; Pan, Yu-jiao; Wang, Chih-hung; Sun, Chin-hung

2010-01-01

11

DETERMINATION OF GIARDIA LAMBLIA CYST INFECTIVE DOSE FOR THE MONGOLIAN GERBIL (MERIONES UNQUICULATUS)  

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The purpose of this study was to determine the I.D.50 for Giardia lamblia (CDC:0284:1) cysts in Mongolian gerbils (Meriones unquiculatus) and compare it to human infectivity data. ysts were purified from Mongolian gerbil feces and diluted to produce inocula for each dosage group....

12

??????: Giardia lamblia virus  

Full Text Available Viruses Totiviridae Giardia lamblia virus GLV (acronym) NCBI 29255 Giardia lamblia virus (scient ific name) NCBI 29255 Giardia lamblia virus. (misspelling) NCBI 29255 Giardia vir us sp. (synonym) NCBI 29255 giardia virus GLV (misnomer) NCBI 29255

13

Enzyme immunoassay for detection of Giardia lamblia cyst antigens in formalin-fixed and unfixed human stool.  

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An antigen-capture enzyme-linked immunosorbent assay employing rabbit and mouse antisera to Giardia lamblia cyst antigens was developed for the diagnosis of Giardia infection through detection of G. lamblia-specific stool antigens in cell-free aqueous eluates of human stool. This is the first report of the use of anti-cyst antibodies in an enzyme immunoassay for G. lamblia. The assay gave a positive result with 54 of 59 stools from patients with symptomatic, clinically diagnosed giardiasis, g...

Stibbs, H. H.; Samadpour, M.; Manning, J. F.

1988-01-01

14

Improved specificity for Giardia lamblia cyst quantification in wastewater by development of a real-time PCR method.  

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The protozoan parasite Giardia lamblia is the most common cause of waterborne disease outbreaks associated with drinking water in the United States. The conventional method used for the enumeration of Giardia cysts in water is based on immunofluorescence with monoclonal antibodies. It is tedious and time-consuming and has the major drawback to be non-specific for the only species infecting humans, G. lamblia. We have developed a real-time polymerase chain reaction (PCR) method using fluorescent TaqMan technology, which improved the specificity of G. lamblia cyst quantification compared to the immunofluorescence assay (IFA). However, this PCR was not totally specific for G. lamblia species and amplified Giardia ardeae target as well. This method showed a sensitivity of 0.45 cysts per reaction and an efficiency of 95% in purified suspensions. We have then applied this quantification method to raw wastewater, a medium containing numerous debris, particles and PCR inhibitors. The adaptation to these environmental samples was realized by a screening of three cyst purification methods and six DNA extraction protocols. Real-time quantification was accomplished by the simultaneous amplification of unknown samples and a tenfold serial dilution of purified G. lamblia cysts. For all samples, the concentrations observed with TaqMan PCR method were compared to the IFA values. Giardia spp. cysts were detected in all non-spiked raw wastewater samples with IFA procedure and the concentrations of Giardia spp. cysts used for the comparison between the two methods ranged between 3.3x10(2)/l and 4.3x10(3)/l. The highest TaqMan PCR/IFA ratios were observed when Percoll/sucrose flotation was combined with DNA extraction protocol optimized for cyst wall lysis, impurities adsorption on a resin, and double step protein digestion and column purification. The concentrations observed with this TaqMan PCR method ranged from 2.5x10(2) to 2.4x10(3) G. lamblia cysts/l and only one sample resulted in a no amplification curve. Thus, we developed a TaqMan PCR method increasing the rapidity and specificity of G. lamblia cyst quantification. The combination of Percoll/sucrose flotation and DNA extraction optimized protocol before TaqMan assay has provided a good indication of the G. lamblia contamination level in raw sewage samples. PMID:15003687

Bertrand, Isabelle; Gantzer, Christophe; Chesnot, Thierry; Schwartzbrod, Janine

2004-04-01

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New Method Using Sedimentation and Immunomagnetic Separation for Isolation and Enumeration of Cryptosporidium parvum Oocysts and Giardia lamblia cysts  

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A new method for the isolation of Cryptosporidium parvum oocysts and Giardia lamblia cysts from biosolid samples has been developed that utilizes sedimentation and immunomagnetic separation. The method was used to recover stained cysts and oocysts (spike organisms) from primary settled sewage sludge, anaerobically digested sewage sludge, and bovine manure. Recovery efficiencies associated with this method were approximately 40 to 60% and were significantly greater than those associated with s...

Massanet-nicolau, Jaime

2003-01-01

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Adaptor protein 2 regulates receptor-mediated endocytosis and cyst formation in Giardia lamblia.  

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The parasite Giardia lamblia possesses PVs (peripheral vacuoles) that function as both endosomes and lysosomes and are implicated in the adaptation, differentiation and survival of the parasite in different environments. The mechanisms by which Giardia traffics essential proteins to these organelles and regulates their secretion have important implications in the control of parasite dissemination. In the present study, we describe the participation of the heterotetrameric clathrin-adaptor protein gAP2 (Giardia adaptor protein 2) complex in lysosomal protein trafficking. A specific monoclonal antibody against the medium subunit (gmu2) of gAP2 showed localization of this complex to the PVs, cytoplasm and plasma membrane in the growing trophozoites. gAP2 also co-localized with clathrin in the PVs, suggesting its involvement in endocytosis. Uptake experiments using standard molecules for the study of endocytosis revealed that gAP2 specifically participated in the endocytosis of LDL (low-density lipoprotein). Targeted down-regulation of the gene encoding gmu2 in growing and encysting trophozoites resulted in a large decrease in the amount of cell growth and cyst wall formation, suggesting a distinct mechanism in which gAP2 is directly involved in both endocytosis and vesicular trafficking. PMID:20199400

Rivero, Maria R; Vranych, Cecilia V; Bisbal, Mariano; Maletto, Belkys A; Ropolo, Andrea S; Touz, Maria C

2010-05-15

17

Selective condensation drives partitioning and sequential secretion of cyst wall proteins in differentiating Giardia lamblia.  

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Controlled secretion of a protective extracellular matrix is required for transmission of the infective stage of a large number of protozoan and metazoan parasites. Differentiating trophozoites of the highly minimized protozoan parasite Giardia lamblia secrete the proteinaceous portion of the cyst wall material (CWM) consisting of three paralogous cyst wall proteins (CWP1-3) via organelles termed encystation-specific vesicles (ESVs). Phylogenetic and molecular data indicate that Diplomonads have lost a classical Golgi during reductive evolution. However, neogenesis of ESVs in encysting Giardia trophozoites transiently provides basic Golgi functions by accumulating presorted CWM exported from the ER for maturation. Based on this "minimal Golgi" hypothesis we predicted maturation of ESVs to a trans Golgi-like stage, which would manifest as a sorting event before regulated secretion of the CWM. Here we show that proteolytic processing of pro-CWP2 in maturing ESVs coincides with partitioning of CWM into two fractions, which are sorted and secreted sequentially with different kinetics. This novel sorting function leads to rapid assembly of a structurally defined outer cyst wall, followed by slow secretion of the remaining components. Using live cell microscopy we find direct evidence for condensed core formation in maturing ESVs. Core formation suggests that a mechanism controlled by phase transitions of the CWM from fluid to condensed and back likely drives CWM partitioning and makes sorting and sequential secretion possible. Blocking of CWP2 processing by a protease inhibitor leads to mis-sorting of a CWP2 reporter. Nevertheless, partitioning and sequential secretion of two portions of the CWM are unaffected in these cells. Although these cysts have a normal appearance they are not water resistant and therefore not infective. Our findings suggest that sequential assembly is a basic architectural principle of protective wall formation and requires minimal Golgi sorting functions. PMID:20386711

Konrad, Christian; Spycher, Cornelia; Hehl, Adrian B

2010-04-01

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Automated 3D detection and classification of Giardia lamblia cysts using digital holographic microscopy with partially coherent source  

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Over the past century, monitoring of Giardia lamblia became a matter of concern for all drinking water suppliers worldwide. Indeed, this parasitic flagellated protozoan is responsible for giardiasis, a widespread diarrhoeal disease (200 million symptomatic individuals) that can lead immunocompromised individuals to death. The major difficulty raised by Giardia lamblia's cyst, its vegetative transmission form, is its ability to survive for long periods in harsh environments, including the chlorine concentrations and treatment duration used traditionally in water disinfection. Currently, there is a need for a reliable, inexpensive, and easy-to-use sensor for the identification and quantification of cysts in the incoming water. For this purpose, we investigated the use of a digital holographic microscope working with partially coherent spatial illumination that reduces the coherent noise. Digital holography allows one to numerically investigate a volume by refocusing the different plane of depth of a hologram. In this paper, we perform an automated 3D analysis that computes the complex amplitude of each hologram, detects all the particles present in the whole volume given by one hologram and refocuses them if there are out of focus using a refocusing criterion based on the integrated complex amplitude modulus and we obtain the (x,y,z) coordinates of each particle. Then the segmentation of the particles is processed and a set of morphological and textures features characteristic to Giardia lamblia cysts is computed in order to classify each particles in the right classes.

El Mallahi, A.; Detavernier, A.; Yourassowsky, C.; Dubois, F.

2012-05-01

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Adaptor Protein 2 Regulates Receptor-Mediated Endocytosis and Cyst Formation in Giardia lamblia  

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The parasite Giardia lamblia possesses peripheral vacuoles (PVs) that function as both endosomes and lysosomes and are implicated in the adaptation, differentiation, and survival of the parasite in different environments. The mechanisms by which Giardia traffics essential proteins to these organelles and regulates their secretion have important implications in the control of parasite dissemination. In this study, we describe the participation of the heterotetrameric clathrin-adaptor protein g...

Rivero, Maria R.; Vranych, Cecilia V.; Bisbal, Mariano; Maletto, Belkys A.; Ropolo, Andrea S.; Touz, Maria C.

2010-01-01

20

EXPERIMENTAL INFECTION OF MONGREL DOGS WITH 'GIARDIA LAMBLIA' CYSTS AND CULTURED TROPHOZOITES  

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In light of recent epidemiologic data implicating wild and domestic animals in the transmission of giardiasis, a study was undertaken to determine whether mongrel dogs could be infected with Giardia lamblia. After careful screening by stool examination (a minimum of six stools ex...

 
 
 
 
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A novel ARID/Bright-like protein involved in transcriptional activation of cyst wall protein 1 gene in Giardia lamblia.  

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The capability of protozoan parasite Giardia lamblia to encyst is critical for survival outside the host and its transmission. AT-rich interaction domain (ARID) or Bright homologs constitute a large family of transcription factors in higher eukaryotes that regulate cell proliferation, development, and differentiation. We asked whether Giardia has ARID-like genes and whether they influence gene expression during Giardia encystation. Blast searches of the Giardia genome data base identified two genes with putative ARID/Bright domains (gARID1 and 2). Epitope-tagged gARID1 was found to localize to nuclei. Recombinant gARID1 specifically bound to the encystation-induced cyst wall protein (cwp) gene promoters. Mutation analysis revealed that AT-rich initiators were required for binding of gARID1 to the cwp promoters. gARID1 contains several key residues for DNA binding, and its binding sequences are similar to those of the known ARID family proteins. The gARID1 binding sequences were positive cis-acting elements of the cwp1 promoter during both vegetative growth and encystation. We also found that gARID1 transactivated the cwp1 promoter through its binding sequences in vivo. Our results suggest that the ARID family has been conserved during evolution and that gARID1 is an important transactivator in regulation of the Giardia cwp1 gene, which is key to Giardia differentiation into cysts. PMID:17244608

Wang, Chih-Hung; Su, Li-Hsin; Sun, Chin-Hung

2007-03-23

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Experimental Infections of Neonatal Mice with Cysts of Giardia lamblia Clone GS/M-83-H7 Are Associated with an Antigenic Reset of the Parasite  

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Transmission of the protozoan parasite Giardia lamblia from one to another host individuum occurs through peroral ingestion of cysts which, following excystation in the small intestine, release two trophozoites each. Many studies have focused on the major surface antigen, VSP (for variant surface protein), which is responsible for the antigenic variability of the parasite. By using trophozoites of G. lamblia clone GS/M-83-H7 (expressing VSP H7) and the neonatal mouse model for experimental in...

Von Allmen, N.; Bienz, M.; Hemphill, A.; Mu?ller, N.

2004-01-01

23

The application of on-chip optofluidic microscopy for imaging Giardia lamblia trophozoites and cysts  

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The optofluidic microscope (OFM) is a lensless, low-cost and highly compact on-chip device that can enable high-resolution microscopy imaging. The OFM performs imaging by flowing/scanning the target objects across a slanted hole array; by measuring the time-varying light transmission changes through the holes, we can then render images of the target objects at a resolution that is comparable to the holes' size. This paper reports the adaptation of the OFM for imaging Giardia lamblia trophozoi...

Lee, Lap Man; Cui, Xiquan; Yang, Changhuei

2009-01-01

24

The proteome landscape of Giardia lamblia encystation  

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Giardia lamblia is an intestinal protozoan parasite required to survive in the environment in order to be transmitted to a new host. To ensure parasite survival, flagellated trophozoites colonizing the small intestine differentiate into non-motile environmentally-resistant cysts which are then shed in the environment. This cell differentiation process called encystation is characterized by significant morphological remodeling which includes secretion of large amounts of cyst wall material. Al...

Faso, Carmen; Bischof, Sylvain; Hehl, Adrian B.

2013-01-01

25

INACTIVATION OF 'GIARDIA' CYSTS BY CHLORINE  

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This study was undertaken to determine the viability of Giardia lamblia cysts shed from an asymptomatic carrier and to correlate the chlorine resistance of these cysts with those from a symptomatic carrier and another Giardia species, G. muris, which is infective for mice....

26

Treatment of Intestinal 'Entamoeba histolytica' and 'Giardia lamblia' with Metronidazole, Tinidazole and Ornidazole: A Comparative Study,  

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Metronidazole, tinidazole and ornidazole were compared in patients treated for Entamoeba histolytica or Giardia lamblia intestinal infections. Only patients with three positive stool specimens for trophozoites and/or cysts of El histolytica or G. lamblia ...

S. Bassily Z. Farid N. A. El-Masry E. M. Mikhail

1987-01-01

27

PURE CULTURE METHOD: GIARDIA LAMBLIA FROM DIFFERENT STOOL SAMPLES  

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Introduction. Giardiasis is one of the health problems in the world including Iran. To determine the biochemical and biological problems and also identification of various strains, it is essential to obtain pure culture and then mass production of Giardia lamblia. The goal of this study was to isolate this protozoa purely.
Methods. Giardia lamblia cysts were isolated fro...

Yousefi, H. A.

2000-01-01

28

Lectin binding by Giardia lamblia.  

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Surface carbohydrates of Giardia lamblia were examined using six plant lectins chosen because of their specificity for major carbohydrates moieties. The binding to axenically grown G. lamblia trophozoites was assessed in both a quantitative microagglutination assay and a fluorescence assay. Of the six lectins tested, wheat germ agglutinin (WGA) agglutinated the highest percentage (22.9 +/- 3.7%) of live trophozoites, and fluorescein-labeled WGA (100 micrograms/ml) bound to 98 +/- 5% of them. ...

1981-01-01

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DETECTION OF GIARDIA MURIS AND GIARDIA LAMBLIA CYSTS BY IMMUNOFLUORESCENCE IN ANIMAL TISSUES AND FECAL SAMPLES SUBJECTED TO CYCLES OF FREEZING AND THAWING  

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The effects of freezing and thawing on the detection of selected Giardia spp. cysts were investigated using immunofluorescence, bright field microscopy, and low voltage scanning electron microscopy (SEM). iardia muris cysts were obtained from either animal carcasses, fecal pellet...

30

The Comparison of the Efficacy of Various Fixatives on Diverse Staining Methods of Giardia lamblia Cyst  

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Full Text Available The definite and exact diagnosis of protozoa is possible using high magnification objective lenses, provided that suitable stained smears are prepared. Therefore, the appropriateness of both fixative and staining methods to the species of parasite, which is the main objective of this study, is important. In this study, five various fixatives including (Merthiolate iodine formalin MIF, (Sodium acetate-acetic acid formalin SAF, (Polyvinyl alcohol PVA, formalin and schaudinn and four types of stains including Hematoxylin I, Hematoxylin II, Trichrome and Carbol-fuchsin were prepared using standard procedures. After the smears of stool samples containing Giadria lamblia cyst were prepared and kept for 24 h in various fixatives, the study was carried out using the four above-mentioned stains by changing the ingredients and time as well as by repeating the experiments. After fixing and staining all the smears in identical conditions along with the implementing interferences in the staining process, the following results were eventually obtained considering the morphologic indexes and negative and positive scores (from 1 to 20: formalin with 17 scores in hematoxylin I staining, formalin and SAF with 15 and 14 scores, respectively in Hematoxylin II staining, MIF with 13 scores in Trichrome staining and SAF, PVA, MIF with 11.5, 11.5 and 11 scores, respectively in carbol-fuchsin staining were found to be the best fixatives. Hematoxylin I staining using formalin fixative with 17 scores showed the best result while the maximum score for Carbol-fuchsin staining was 11.5 showing a necessity for more expenditure, time and expert cooperation to reach ideal results.

E. Badparva

2009-01-01

31

Antigenic conservation and variation in Giardia cysts from various vertebrate hosts.  

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Monoclonal antibodies produced against Giardia muris cysts reacted in indirect immunofluorescence with homologous cysts and cysts from a Giardia-infected wild Norway rat but did not cross-react with Giardia lamblia cysts of human, dog, or beaver sources. Another monoclonal antibody raised against Giardia simoni cysts from the Norway rat reacted with homologous cysts (rat) and cross-reacted with cysts from a cow. The demonstration of antigenic differences at the cyst surfaces of Giardia organi...

Riley, E. T.; Stibbs, H. H.

1989-01-01

32

Pyrimidine salvage in Giardia lamblia  

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We have found that the anaerobic protozoan parasite Giardia lamblia is incapable of de novo pyrimidine metabolism, as shown by its inability to incorporate orotate, bicarbonate, and aspartate into the pyrimidine nucleotide pool. Results from high performance liquid chromatography of pyrimidine and pyrimidine nucleoside pulse-labeled nucleotide pools and enzyme assays suggest that the parasite satisfies its pyrimidine nucleotide needs predominantly through salvage of uracil by a cytoplasmic ur...

1985-01-01

33

Codon usage in Giardia lamblia.  

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A codon usage table for the intestinal parasite Giardia lamblia was generated by analysis of the nucleotide sequences of eight genes comprising 3,135 codons. Codon usage revealed a biased use of synonymous codons with a preference for NNC codons (42.1%). The codon usage of G. lamblia more closely resembles that of the prokaryote Halobacterium halobium (correlation coefficient r = 0.73) rather than that of other eukaryotic protozoans, i.e. Trypanosoma brucei (r = 0.434) and Plasmodium falciparum (r = -0.31). These observations are consistent with the view that G. lamblia represents the first line of descent from the ancestral cells that first took on eukaryotic features. PMID:1522548

Char, S; Farthing, M J

1992-01-01

34

Cholesterol starvation induces differentiation of the intestinal parasite Giardia lamblia.  

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Giardia lamblia, like most human intestinal parasitic protozoa, sustains fundamental morphological and biochemical changes to survive outside the small intestine of its mammalian host by differentiating into an infective cyst. However, the stimulus that triggers this differentiation remains totally undefined. In this work, we demonstrate the induction of cyst formation in vitro when trophozoites are starved for cholesterol. Expression of cyst wall proteins was detected within encystation-spec...

Luja?n, H. D.; Mowatt, M. R.; Byrd, L. G.; Nash, T. E.

1996-01-01

35

Pyrimidine salvage in Giardia lamblia.  

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We have found that the anaerobic protozoan parasite Giardia lamblia is incapable of de novo pyrimidine metabolism, as shown by its inability to incorporate orotate, bicarbonate, and aspartate into the pyrimidine nucleotide pool. Results from high performance liquid chromatography of pyrimidine and pyrimidine nucleoside pulse-labeled nucleotide pools and enzyme assays suggest that the parasite satisfies its pyrimidine nucleotide needs predominantly through salvage of uracil by a cytoplasmic uracil phosphoribosyltransferase. Exogenous uridine and cytidine are primarily converted to uracil by the action of uridine hydrolase and cytidine deaminase before incorporation into nucleotide pools. Direct salvage of cytosine occurs to a relatively limited extent via cytosine phosphoribosyltransferase. G. lamblia relies on salvage of exogenous thymidine for ribosylthymine monophosphate (TMP) synthesis, accomplished primarily through the action of a 100,000 g-pelletable thymidine phosphotransferase. PMID:3973534

Aldritt, S M; Tien, P; Wang, C C

1985-03-01

36

Experimental infections of neonatal mice with cysts of Giardia lamblia clone GS/M-83-H7 are associated with an antigenic reset of the parasite.  

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Transmission of the protozoan parasite Giardia lamblia from one to another host individuum occurs through peroral ingestion of cysts which, following excystation in the small intestine, release two trophozoites each. Many studies have focused on the major surface antigen, VSP (for variant surface protein), which is responsible for the antigenic variability of the parasite. By using trophozoites of G. lamblia clone GS/M-83-H7 (expressing VSP H7) and the neonatal mouse model for experimental infections, we quantitatively assessed the process of antigenic variation of the parasite on the transcriptional level. In the present study, variant-specific regions identified on different GS/M-83-H7 vsp sequences served as targets for quantitative reverse transcription-PCR to monitor alterations in vsp mRNA levels during infection. Respective results demonstrated that antigenic switching of both the duodenal trophozoite and the cecal cyst populations was associated with a massive reduction in vsp H7 mRNA levels but not with a simultaneous increase in transcripts of any of the subvariant vsp genes analyzed. Most importantly, we also explored giardial variant-type formation and vsp mRNA levels after infection of mice with cysts. This infection mode led to an antigenic reset of the parasite in that a VSP H7-negative inoculum "converted" into a population of intestinal trophozoites that essentially consisted of the original VSP H7 type. This antigenic reset appears to be associated with excystation rather than with a selective process which favors expansion of a residual population of VSP H7 types within the antigenically diversified cyst inoculum. Based on these findings, the VSP H7 type has to be regarded as a predominant variant of G. lamblia clone GS/M-83-H7 which (re-)emerges during early-stage infection and may contribute to an optimal establishment of the parasite within the intestine of the experimental murine host. PMID:15271938

von Allmen, N; Bienz, M; Hemphill, A; Müller, N

2004-08-01

37

Putative SF2 helicases of the early-branching eukaryote Giardia lamblia are involved in antigenic variation and parasite differentiation into cysts  

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Full Text Available Abstract Background Regulation of surface antigenic variation in Giardia lamblia is controlled post-transcriptionally by an RNA-interference (RNAi pathway that includes a Dicer-like bidentate RNase III (gDicer. This enzyme, however, lacks the RNA helicase domain present in Dicer enzymes from higher eukaryotes. The participation of several RNA helicases in practically all organisms in which RNAi was studied suggests that RNA helicases are potentially involved in antigenic variation, as well as during Giardia differentiation into cysts. Results An extensive in silico analysis of the Giardia genome identified 32 putative Super Family 2 RNA helicases that contain almost all the conserved RNA helicase motifs. Phylogenetic studies and sequence analysis separated them into 22 DEAD-box, 6 DEAH-box and 4 Ski2p-box RNA helicases, some of which are homologs of well-characterized helicases from higher organisms. No Giardia putative helicase was found to have significant homology to the RNA helicase domain of Dicer enzymes. Additionally a series of up- and down-regulated putative RNA helicases were found during encystation and antigenic variation by qPCR experiments. Finally, we were able to recognize 14 additional putative helicases from three different families (RecQ family, Swi2/Snf2 and Rad3 family that could be considered DNA helicases. Conclusions This is the first comprehensive analysis of the Super Family 2 helicases from the human intestinal parasite G. lamblia. The relative and variable expression of particular RNA helicases during both antigenic variation and encystation agrees with the proposed participation of these enzymes during both adaptive processes. The putatives RNA and DNA helicases identified in this early-branching eukaryote provide initial information regarding the biological role of these enzymes in cell adaptation and differentiation.

Gargantini Pablo R

2012-11-01

38

Mechanisms of adaptation in the intestinal parasite Giardia lamblia.  

Science.gov (United States)

Giardia lamblia, a parasite of humans, is a major source of waterborne diarrhoeal disease. Giardia is also an excellent system to study basic biochemical processes because it is a single-celled eukaryote with a small genome and its entire life cycle can be replicated in vitro. Giardia trophozoites undergo fundamental changes to survive outside the intestine of their host by differentiating into infective cysts. Encystation entails the synthesis, processing, transport, secretion and extracellular assembly of cyst wall components. To survive within the intestine, Giardia undergoes antigenic variation, a process by which the parasite continuously switches its major surface molecules, allowing the parasite to evade the host's immune response and produce chronic and recurrent infections. The objective of the present chapter is to provide a better understanding of the molecular mechanisms involved in adaptation and differentiation in Giardia, with a particular focus on the process of encystation and antigenic variation of this interesting micro-organism. PMID:22023449

Lujan, Hugo D

2011-01-01

39

N-acetyl-D-glucosamine is present in cysts and trophozoites of Giardia lamblia and serves as receptor for wheatgerm agglutinin.  

Science.gov (United States)

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. PMID:2128647

Ortega-Barria, E; Ward, H D; Evans, J E; Pereira, M E

1990-12-01

40

EFFECT OF HALOGENS ON 'GIARDIA' CYST VIABILITY  

Science.gov (United States)

The objective of this research was to determine the effect of chlorine and other disinfecting agents on Giardia lamblia cyst viability. The agents studied included free residual chlorine and six different methods recommended for emergency disinfection of small quantities of water...

 
 
 
 
41

Identification of chitin as a structural component of Giardia cysts.  

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The intestinal parasite Giardia lamblia is a significant cause of diarrheal disease, which is perpetuated by the infective cyst form of the parasite. Although a rational approach to the control of giardiasis would be to inhibit cyst formation, nothing is known of the chemical composition of the cyst wall or of its biosynthesis. In these studies, we have shown that chitin is a major structural component of G. lamblia and G. muris cyst walls. This conclusion is based on the finding that chitina...

Ward, H. D.; Alroy, J.; Lev, B. I.; Keusch, G. T.; Pereira, M. E.

1985-01-01

42

Giardia lamblia infections in adult mice.  

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An adult mouse-Giardia lamblia model was developed and used to study host-parasite interactions, including antigenic variation. The H7/1 clone of isolate GS infected mice consistently and produced infections in 14 mouse strains tested. Infection patterns were mouse strain and Giardia isolate dependent. Antigenic variation occurred in immunocompetent mice but not in mice with severe combined immunodeficiency.

Byrd, L. G.; Conrad, J. T.; Nash, T. E.

1994-01-01

43

Tonic Shock Induces Detachment of Giardia lamblia  

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The single-celled organism Giardia lamblia colonizes the small intestine of a wide variety of hosts, including humans. Giardiasis infections can cause severe gastrointestinal symptoms and pose a major health concern in the developing world. Giardia are known to attach robustly to a variety of surfaces, but the conditions that influence this attachment are not known. In this study, we examined the behavior of attached Giardia parasites exposed to rapid changes in solution properties, like thos...

Hansen, Wendy R.; Fletcher, Daniel A.

2008-01-01

44

Purine salvage networks in Giardia lamblia  

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Purine metabolism in Giardia lamblia was investigated by monitoring incorporation of radiolabeled precursors into purine nucleotides in the log-phase trophozoites cultivated in vitro in axenic media and incubated in buffered saline glucose. The lack of incorporation of formate, glycine, hypoxanthine, inosine, and xanthine into the nucleotide pool suggests the absence of de novo purine nucleotide synthesis and the inability to form IMP as the precursor of AMP and GMP in G. lamblia. Only adenin...

1983-01-01

45

PURE CULTURE METHOD: GIARDIA LAMBLIA FROM DIFFERENT STOOL SAMPLES  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. Giardiasis is one of the health problems in the world including Iran. To determine the biochemical and biological problems and also identification of various strains, it is essential to obtain pure culture and then mass production of Giardia lamblia. The goal of this study was to isolate this protozoa purely.
Methods. Giardia lamblia cysts were isolated from 50 stool samples by use of floating of a four - layer of sucrose method. The cysts were transfered to an inducing solution. Subsequently, they were cultured in a modified culture medium (TYIS-33. Following excystation of trophozoite and its multiplication, the parasite was caltured and purified.
Findings. Excitation of trophozoite was observed in 40 samples (80 percent from which 22 samples (55 percent yielded pure culture. The doubling time was approximately 13hr and the peak of parasite was observed between third and fourth days.
Conclusion. The proliferation and growth rate of Giardia lamblia have enabled us to use this method widely. Cystein and ascorbic acid which are present in the induction solution, have a key role in excystation of trophozoite. Purification and passage of samples has facilitated the culture of this parasite in vitro. Therefore this method has yielded better results in comparison with other studies. This is probably due to a decrease in the amount of bovine bile or using different strains of Giardia lamblia in the present study.

H.A YOUSEFI

2000-03-01

46

Effect of corticosteroid and irradiation on experimental Giardia lamblia infection in mice  

International Nuclear Information System (INIS)

Following infection with the parasite, Giardia lamblia, the faecal excretion rate of these cysts was studied in mice pre-treated with cortisone and/or whole body irradiation compared to controls. The cortisone/irradiation treatment increased the susceptibility to infection, as shown by the higher cyst excretion rate. Thus these treatments presumably depressed the cellular and humoral immunity normally present in G. lamblia infected mice. (UK)

1980-01-01

47

Diagnosis of Giardia lamblia infections by detection of parasite-specific antigens.  

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Antigen detection methods may facilitate diagnosis of Giardia lamblia in stool specimens. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and immunoblotting, G. lamblia cysts and trophozoites share several antigens, especially in the 65-kilodalton and 30- to 34-kilodalton regions. By using blind methods, we compared results obtained by counterimmunoelectrophoresis using cyst-immune rabbit serum and by enzyme-linked immunosorbent assay (ELISA) using trophozo...

Janoff, E. N.; Craft, J. C.; Pickering, L. K.; Novotny, T.; Blaser, M. J.; Knisley, C. V.; Reller, L. B.

1989-01-01

48

Cholesterol starvation induces differentiation of the intestinal parasite Giardia lamblia.  

Science.gov (United States)

Giardia lamblia, like most human intestinal parasitic protozoa, sustains fundamental morphological and biochemical changes to survive outside the small intestine of its mammalian host by differentiating into an infective cyst. However, the stimulus that triggers this differentiation remains totally undefined. In this work, we demonstrate the induction of cyst formation in vitro when trophozoites are starved for cholesterol. Expression of cyst wall proteins was detected within encystation-specific secretory vesicles 90 min after the cells were placed in lipoprotein-deficient TYI-S-33 medium. Four cloned lines derived from two independent Giardia isolates were tested, and all formed cysts similarly. Addition of cholesterol, low density or very low density lipoproteins to the lipoprotein-deficient culture medium, inhibited the expression of cyst wall proteins, the generation of encystation-specific vesicles, and cyst wall biogenesis. In contrast, high density lipoproteins, phospholipids, bile salts, or fatty acids had little or no effect. These results indicate that cholesterol starvation is necessary and sufficient for the stimulation of Giardia encystation in vitro and, likely, in the intestine of mammalian hosts. PMID:8755526

Luján, H D; Mowatt, M R; Byrd, L G; Nash, T E

1996-07-23

49

A Detailed, Hierarchical Study of Giardia lamblia's Ventral Disc Reveals Novel Microtubule-Associated Protein Complexes  

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Giardia lamblia is a flagellated, unicellular parasite of mammals infecting over one billion people worldwide. Giardia's two-stage life cycle includes a motile trophozoite stage that colonizes the host small intestine and an infectious cyst form that can persist in the environment. Similar to many eukaryotic cells, Giardia contains several complex microtubule arrays that are involved in motility, chromosome segregation, organelle transport, maintenance of cell shape and transformation between...

Schwartz, Cindi L.; Heumann, John M.; Dawson, Scott C.; Hoenger, Andreas

2012-01-01

50

DO AUTOCHTHONOUS BACTERIA AFFECT GIARDIA CYST SURVIVAL IN NATURAL WATERS?  

Science.gov (United States)

Giardia lamblia survives in and is transmitted to susceptible human and animal populations via water, where it is present in an environmentally resistant cyst form. Previous research has highlighted the importance of water temperature in cyst survival, and has also suggested the ...

51

Propidium iodide as an indicator of Giardia cyst viability.  

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The use of propidium iodide, whose uptake indicates cell death or damage, was investigated to assess the viability of heat-inactivated and chemically inactivated Giardia muris cysts. This was done by comparing propidium iodide staining with excystation. We first determined that propidium iodide could be used with an immunofluorescence detection procedure by showing that the percentages of Giardia lamblia cysts stained with this dye before and after subjecting them to a fluorescence detection ...

Sauch, J. F.; Flanigan, D.; Galvin, M. L.; Berman, D.; Jakubowski, W.

1991-01-01

52

Isolation and identification of a Giardia lamblia-specific stool antigen (GSA 65) useful in coprodiagnosis of giardiasis.  

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A Giardia lamblia-specific antigen (GSA 65) was isolated from stools of G. lamblia-positive patients by crossed- and line-immunoelectrophoresis and counterimmunoelectrophoresis (CIE) in agarose by using rabbit antiserum prepared against G. lamblia cysts. CIE with rabbit anti-GSA 65 monospecific antiserum revealed that GSA 65 was present in aqueous stool eluates of giardiasis patients and in cysts and trophozoites of the parasite. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of im...

Rosoff, J. D.; Stibbs, H. H.

1986-01-01

53

Opsonization in vitro of Giardia lamblia trophozoites.  

Science.gov (United States)

The ability of peritoneal rabbit macrophages from immunized and nonimmunized animals to phagocytose Giardia lamblia trophozoites in the presence of serum was studied and compared in an in vitro system. The rabbits which served as the source of immune serum and macrophages were injected repeatedly at multiple sites (intramuscularly, subcutaneously, and intradermally) with a mixture of G. lamblia trophozoites and Freund complete adjuvant. In the presence of normal rabbit serum, a low level of phagocytosis of Giardia trophozoites by normal and immune macrophages was observed. In the presence of hyperimmune rabbit serum, an increased phagocytic activity of both types of macrophages occurred. The opsonic activity was similar whether whole serum or purified immunoglobulin G was used and whether or not these were heat inactivated. G. lamblia trophozoites in suspension were shown to be agglutinated in the presence of hyperimmune serum. Tests employing serial dilutions of hyperimmune serum resulted in a parallel loss of opsonifying and agglutinating activities. It is suggested that opsonization in vivo may play a role in the ability of the host to limit infection by these organisms. Images

Radulescu, S; Meyer, E A

1981-01-01

54

Small-intestinal factors promote encystation of Giardia lamblia in vitro.  

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Bile salts and fatty acids stimulated differentiation of cultured Giardia lamblia trophozoites into water-resistant cysts at the slightly alkaline pH of the small intestinal lumen. Maximum encystation occurred at pH 7.8. Thus, specific small-intestinal factors may influence encystation in vivo as well as in vitro.

1988-01-01

55

DIATOMACEOUS EARTH FILTRATION OF 'GIARDIA' CYSTS AND OTHER SUBSTANCES  

Science.gov (United States)

Pilot-plant tests resulted in virtually 100% removals of Giardia lamblia cysts for both coarse and fine grades of diatomaceous earth over a wide range of conditions. Removals of turbidity and total coliform bacteria were functionally dependent on the grade of diatomaceous earth. ...

56

[Histocompatibility antigens and Giardia lamblia parasitosis].  

Science.gov (United States)

A study was made of the HLA in 41 children between the ages of 4 and 13 years, with the parasite Giardia lamblia, of ages between 4 and 13 years. The different histocompatibility antigens were compared in relationship to the clinical and analytical aspects of the patients. Individuals with HLA A1 and/or blood group A have a greater probability of contracting this parasite. Other relationships found were HLA A19 and vomiting. HLA A9 and abdominal pain and HLA B7 with alterations in the gastrointestinal mucous. PMID:1543292

de Manueles Jiménez, J; Martín Ruano, A; Martín Sanz, A J; Martín Ruano, J; Sánchez Calvín, M T

1992-01-01

57

Giardia lamblia and Helicobater pylori Coinfection  

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"nBackground: Giardia lamblia and Helicobacter pylori are two flagellate microorganisms that grow in duodenum and stom­ach. The aim of this study was to evaluate the prevalence of them in patients with dyspepsia and other GI disorders. "nMethods: In this cross-sectional study, co-infection of above-mentioned agents was investigated in a group of 130 patients [me­dian age of 40 yr (range=11-79) including 76 males (58.8%)] with dyspepsia using three methods of duodenal aspirat...

Shafie, R.; MR Jahani; Rezaeian, M.; Amini, M.; Ar, Metvayi; Ebrahimi Daryani, N.; MR Keramati

2009-01-01

58

Regulation of antigenic variation in Giardia lamblia.  

Science.gov (United States)

Antigenic variation, a clonal phenotypic variation developed by microorganisms, involves the permanent switching of homologous, antigenically different cell surface molecules. In pathogenic microorganisms, antigenic variation is often described as a mechanism to evade the host immune system and therefore is responsible for the generation of chronic and/or recurrent infections. However, antigenic variation has also been involved in expanding host diversity and differential courses of the diseases. The intestinal protozoan parasite Giardia lamblia undergoes antigenic variation through the continuous exchange of approximately 200 variant-specific surface proteins. Here we review the principal issues regarding the significance of antigenic variation during Giardia infections, the particular features of the variant-specific surface proteins, and the current knowledge on the mechanisms that regulate this process, as well as the relevance of disrupting antigenic variation as a novel approach to design effective antiparasitic vaccines. PMID:21740226

Prucca, César G; Rivero, Fernando D; Luján, Hugo D

2011-01-01

59

Giardia lamblia and Helicobater pylori Coinfection  

Directory of Open Access Journals (Sweden)

Full Text Available "nBackground: Giardia lamblia and Helicobacter pylori are two flagellate microorganisms that grow in duodenum and stom­ach. The aim of this study was to evaluate the prevalence of them in patients with dyspepsia and other GI disorders. "nMethods: In this cross-sectional study, co-infection of above-mentioned agents was investigated in a group of 130 patients [me­dian age of 40 yr (range=11-79 including 76 males (58.8%] with dyspepsia using three methods of duodenal aspiration sam­ple, duodenal biopsy samples and evaluation of stool samples."nResults: : From 105 patients (59 males, 46 females, median age 40 years, range 11-79 entering this study from 3 hospitals, 4 patients (3.8% had G. lamblia and 61 patients (58% had H. pylori. All 4 patients infected by Giardia had also H. pylori infec­tion. Tenesmus (3 out of 4 patients was the most common symptom in patients with H. pylori infection (48 out of 61 pa­tients was reflux. Other symptoms in patients infected with both organisms (4 patients included diarrhea (2 cases, weight loss (2 cases, and loss of appetite (1 case but no report of vomiting."nConclusion: In patients co-infected with Giardia, H.pylori differentiation by physical examination is not possible. So in those patients with positive Rapid Urease Test (RUT, stool examination for Giardia detection is recommended. In addition, met­ronidazole (broad spectrum, anti-protozoal drug can be useful in H. pylori infection.

R Shafie

2009-03-01

60

Molecular characterization of the cis-prenyltransferase of Giardia lamblia  

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Giardia lamblia, the protist that causes diarrhea, makes an Asn-linked-glycan (N-glycan) precursor that contains just two sugars (GlcNAc2) attached by a pyrophosphate linkage to a polyprenol lipid. Because the candidate cis-prenyltransferase of Giardia appears to be more similar to bacterial enzymes than to those of most eukaryotes and because Giardia is missing a candidate dolichol kinase (ortholog to Saccharomyces cerevisiae SEC59 gene product), we wondered how Giardia synthesizes dolichol ...

Grabin?ska, Kariona A.; Cui, Jike; Chatterjee, Aparajita; Guan, Ziqiang; Raetz, Christian R. H.; Robbins, Phillips W.; Samuelson, John

2010-01-01

 
 
 
 
61

Cytochrome b5 from Giardia lamblia.  

Science.gov (United States)

The protozoan intestinal parasite Giardia lamblia lacks mitochondria and the ability to make haem yet encodes several putative haem-binding proteins, including three of the cytochrome b(5) family. We cloned one of these (gCYTb5-I) and expressed it within Escherichia coli as a soluble holoprotein. UV-visible and resonance Raman spectra of gCYTb5-I resemble those of microsomal cytochrome b(5), and homology modelling supports a structure in which a pair of invariant histidine residues act as axial ligands to the haem iron. The reduction potential of gCYTb5-I is -165 mV vs. SHE and is relatively low compared to most values (-110 to +80 mV) for this class of protein. The amino- and carboxy-terminal sequences that flank the central haem-binding core of the Giardia cytochromes are highly charged and differ from those of other family members. A core gCYTb5-I variant lacking these flanking sequences was also able to bind haem. The presence of one actual and two probable functional cytochromes b(5) in Giardia is evidence of uncharacterized cytochrome-mediated metabolic processes within this medically important protist. PMID:23151674

Alam, Samiah; Yee, Janet; Couture, Manon; Takayama, Shin-ichi J; Tseng, Wan-Hsin; Mauk, A Grant; Rafferty, Steven

2012-12-01

62

Sedimentation of Free and Attached Cryptosporidium Oocysts and Giardia Cysts in Water  

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Experimental analysis of the sedimentation velocity of Cryptosporidium parvum oocysts and Giardia lamblia cysts was compared with mathematical description of their sedimentation velocities by using measurements of (oo)cyst size and density and the density and viscosity of the sedimentation medium to determine if the sedimentation kinetics of freely suspended oocysts of C. parvum and cysts of G. lamblia can be described by Stokes’ law. The theoretically calculated sedimentation kinetics show...

Medema, G. J.; Schets, F. M.; Teunis, P. F. M.; Havelaar, A. H.

1998-01-01

63

REVIEW OF METHODS THAT ARE USED TO DETERMINE 'GIARDIA' CYST VIABILITY  

Science.gov (United States)

Over the past 55 years a number of methods have been described for excysting Giardia cysts as a means of determining viability. The excystation methods for G. muris cysts are reliable and reproducible. However, methods published to date for the excystation of G. lamblia cysts, th...

64

BILIARY LIPIDS SUPPORT SERUM-FREE GROWTH OF 'GIARDIA LAMBLIA'  

Science.gov (United States)

Giardia lamblia has only been grown in vitro in media containing serum or serum fractions. How this pathogen can grow in the human small intestinal lumen without serum is not known. The authors found that samples of human hepatic or gall bladder bile maintained G. lamblia surviva...

65

A lesson in survival, by Giardia lamblia.  

Science.gov (United States)

In the relationships between host and parasites, there is a cross-talk that involves diverse mechanisms developed by two different genetic systems during years of evolution. On the one hand, immunocompetent hosts have developed effective innate and acquired immune responses that are used to restrict or avoid parasitism. On the other hand, parasites evade the immune response, expressing different antigens on their surface or by using other specific mechanisms, such as nutrient depletion. In this review, we analyze the survival mechanisms used by the protozoan parasite Giardia lamblia during infection. In particular, we examine the multiple roles played by the enzyme arginine deiminase during colonization of the gut, also involving the parasite's mechanism of antigenic variation. Potential drug targets for the treatment of giardiasis are also discussed. PMID:20953552

Rópolo, Andrea S; Touz, Maria C

2010-01-01

66

Giardia lamblia: uptake of pyrimidine nucleosides.  

Science.gov (United States)

The aerotolerant, anaerobic parasite Giardia lamblia, which depends solely upon salvage pathways for its pyrimidine requirements, was found to transport uridine, cytidine, and thymidine by a carrier mediated mechanism. Support for this conclusion comes from the facts that uptake of radiolabeled uridine, cytidine, and thymidine exhibited saturation kinetics, and uptake of these same radiolabeled nucleosides was inhibited by unlabeled homologs, certain pyrimidine analogs, iodoacetate, and N-ethylmaleimide. Uridine and cytidine (perhaps uracil and cytosine also) are postulated to be transported at a common site which is distinct from the site for thymidine transport. Thymidine does appear to bind nonproductively to the uridine/cytidine transport site, but the reverse of this does not appear to occur. PMID:3569473

Jarroll, E L; Hammond, M M; Lindmark, D G

1987-04-01

67

Identification of chitin as a structural component of Giardia cysts.  

Science.gov (United States)

The intestinal parasite Giardia lamblia is a significant cause of diarrheal disease, which is perpetuated by the infective cyst form of the parasite. Although a rational approach to the control of giardiasis would be to inhibit cyst formation, nothing is known of the chemical composition of the cyst wall or of its biosynthesis. In these studies, we have shown that chitin is a major structural component of G. lamblia and G. muris cyst walls. This conclusion is based on the finding that chitinase specifically destroys the cyst wall, as revealed by electron microscopy. The presence of chitin was also shown directly by lectin binding studies. Of 12 lectins with diverse carbohydrate recognition specificity, only the N-acetylglucosamine-specific lectins wheat germ agglutinin, succinylated wheat germ agglutinin, and tomato lectin bound to cyst walls, as shown by fluorescence microscopy and cytochemistry. Wheat germ agglutinin binding was completely abolished by treatment of the cysts with purified chitinase. This effect was specific since it could be prevented by incubating the enzyme with chitin before treatment of the cysts. Treatment of cysts with N-acetyl-beta-glucosaminidase partially inhibited wheat germ agglutinin binding, whereas other glycosidases and proteases had no effect. These findings indicate that chitin is a major structural component of Giardia cyst walls and raise the possibility that inhibitors of chitin synthesis may be of use in preventing encystation and thus controlling spread of the disease. PMID:4030095

Ward, H D; Alroy, J; Lev, B I; Keusch, G T; Pereira, M E

1985-09-01

68

Attachment of Giardia lamblia to rat intestinal epithelial cells.  

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The human enteric protozoan, Giardia lamblia, has surface membrane lectin activity which mediates parasite adherence to erythrocytes. To determine whether an intestinal binding site exists for this lectin we have studied the interaction in vitro between axenically cultured Giardia trophozoites and isolated rat intestinal epithelial cells. Scanning electron microscopy showed that Giardia attached to the apical microvillus membrane and basolateral membrane of rat enterocytes. Any location on th...

Inge, P. M.; Edson, C. M.; Farthing, M. J.

1988-01-01

69

Role of nitric oxide and superoxide in Giardia lamblia killing  

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Giardia lamblia trophozoites were incubated for 2 h with activated murine macrophages, nitric oxide (NO) donors or a superoxide anion generator (20 mU/ml xanthine oxidase plus 1 mM xanthine). Activated macrophages were cytotoxic to Giardia trophozoites (~60% dead trophozoites). This effect was inhibited (>90%) by an NO synthase inhibitor (200 µM) and unaffected by superoxide dismutase (SOD, 300 U/ml). Giardia trophozoites were killed by the NO donors, S-nitroso-acetyl-penicillamine (SNAP) an...

Fernandes, P. D.; Assreuy, J.

1997-01-01

70

Chitin synthetase in encysting Giardia lamblia and Entamoeba invadens  

International Nuclear Information System (INIS)

Giardia lamblia (Gl) and Entamoeba invadens (Ei) are protozoan parasites with two morphologic stages in their life cycles. Motile trophozoites colonize the intestine of humans and reptiles respectively. Water resistant cysts, which can survive outside the host, transmit infection. In vitro cyst formation of Ei from trophozoites has been reported, and the authors have recently induced in vitro encystation of Gl. Although the cyst walls of both parasites contain chitin, it synthesis by encysting trophozoites has not been reported. The authors now show that encystation conditions greatly increase chitin synthetase (CS) specific activity (incorporation of 3H GlcNAc from UDP-GlcNAc into TCA-or alcohol-precipitable material). Extracts of encysting Gl incorporated 3.6 nmol/mg protein in 5 hr compared to < 0.005 in controls. Extracts of encysting Fi incorporated 4.8 n mol/mg protein, compared to 1.7 in the control. CS activity of both parasites requires preformed chitin. The Gl enzyme requires a reducing agent, is inhibited by digitonin and the CS inhibitors, polyoxin D and Nikkomycin, but not by tunicamycin. The product is digested by chitinase. Ei enzyme does not require a reducing agent and is stimulated by 1 mg/ml digitonin, but inhibited by higher concentrations. These studies demonstrate CS enzymes which may play important roles in encystation of Gl and Ei

1987-05-01

71

Chitin synthetase in encysting Giardia lamblia and Entamoeba invadens  

Energy Technology Data Exchange (ETDEWEB)

Giardia lamblia (Gl) and Entamoeba invadens (Ei) are protozoan parasites with two morphologic stages in their life cycles. Motile trophozoites colonize the intestine of humans and reptiles respectively. Water resistant cysts, which can survive outside the host, transmit infection. In vitro cyst formation of Ei from trophozoites has been reported, and the authors have recently induced in vitro encystation of Gl. Although the cyst walls of both parasites contain chitin, it synthesis by encysting trophozoites has not been reported. The authors now show that encystation conditions greatly increase chitin synthetase (CS) specific activity (incorporation of /sup 3/H GlcNAc from UDP-GlcNAc into TCA-or alcohol-precipitable material). Extracts of encysting Gl incorporated 3.6 nmol/mg protein in 5 hr compared to < 0.005 in controls. Extracts of encysting Fi incorporated 4.8 n mol/mg protein, compared to 1.7 in the control. CS activity of both parasites requires preformed chitin. The Gl enzyme requires a reducing agent, is inhibited by digitonin and the CS inhibitors, polyoxin D and Nikkomycin, but not by tunicamycin. The product is digested by chitinase. Ei enzyme does not require a reducing agent and is stimulated by 1 mg/ml digitonin, but inhibited by higher concentrations. These studies demonstrate CS enzymes which may play important roles in encystation of Gl and Ei.

Das, S.; Gillin, F.D.

1987-05-01

72

Proteomics of Secretory and Endocytic Organelles in Giardia lamblia  

Science.gov (United States)

Giardia lamblia is a flagellated protozoan enteroparasite transmitted as an environmentally resistant cyst. Trophozoites attach to the small intestine of vertebrate hosts and proliferate by binary fission. They access nutrients directly via uptake of bulk fluid phase material into specialized endocytic organelles termed peripheral vesicles (PVs), mainly on the exposed dorsal side. When trophozoites reach the G2/M restriction point in the cell cycle they can begin another round of cell division or encyst if they encounter specific environmental cues. They induce neogenesis of Golgi-like organelles, encystation-specific vesicles (ESVs), for regulated secretion of cyst wall material. PVs and ESVs are highly simplified and thus evolutionary diverged endocytic and exocytic organelle systems with key roles in proliferation and transmission to a new host, respectively. Both organelle systems physically and functionally intersect at the endoplasmic reticulum (ER) which has catabolic as well as anabolic functions. However, the unusually high degree of sequence divergence in Giardia rapidly exhausts phylogenomic strategies to identify and characterize the molecular underpinnings of these streamlined organelles. To define the first proteome of ESVs and PVs we used a novel strategy combining flow cytometry-based organelle sorting with in silico filtration of mass spectrometry data. From the limited size datasets we retrieved many hypothetical but also known organelle-specific factors. In contrast to PVs, ESVs appear to maintain a strong physical and functional link to the ER including recruitment of ribosomes to organelle membranes. Overall the data provide further evidence for the formation of a cyst extracellular matrix with minimal complexity. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium with the dataset identifier PXD000694.

Wampfler, Petra B.; Tosevski, Vinko; Nanni, Paolo; Spycher, Cornelia; Hehl, Adrian B.

2014-01-01

73

Rapid Reinfection by Giardia Lamblia After Treatment in a Hyperendemic Community, During One Year Follow up  

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Background: Giardia lamblia is the most common intestinal parasite in the most parts of Iran, including Hamadan. Treatment of healthy cyst pass...

Fallah, M.

2011-01-01

74

DETERMINATION OF 'GIARDIA' CYST VIABILITY  

Science.gov (United States)

The principal objective of this research was the development of a sensitive, standardized method of determining whether or not Giardia cysts are viable. The availability of such a method is necessary to determine the effect of chemical and physical agents on the viability of thes...

75

Axenic cultivation and characterization of Giardia lamblia isolated from humans in Korea  

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Inoculating of human fecal cysts to suckling Mongolian gerbils, two Giardia lamblia isolates, K1 and K2, were established as axenic cultures. Using this in vitro culture, both isolates were characterized as a "medium-rate grower" upon its growth pattern. These two Giardia isolates were grouped by using two genetic analysis. With genetic analysis of SSU-rDNA sequences, both K1 and K2 were found as members of Hopkins' group 1, despite some nucleotide differences noticed in K1 (5 differences/292...

Park, Soon-jung; Yong, Tai-soon; Yang, Hye-won; Lee, Du-ho; Lee, Kyungwon

1999-01-01

76

DETERMINATION OF THE USE OF SOLID PARTICLE SAMPLERS FOR 'GIARDIA' CYSTS IN NATURAL WATERS  

Science.gov (United States)

The primary objective of this study was to improve the current methodology for concentrating, recovering, and detecting cysts of Giardia lamblia in water supplies. Two sampling processes for the concentration of cysts were examined. One process was diatomaceous earth filtration w...

77

Antigenic switching of TSA 417, a trophozoite variable surface protein, following completion of the life cycle of Giardia lamblia.  

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Expression of TSA 417, the predominant cysteine-rich variable surface protein of Giardia lamblia WB clone C6 trophozoites, did not change during encystation in vitro. However, in vitro excystation of cysts derived in vitro or in vivo consistently produced TSA 417 nonexpressing trophozoite populations, suggesting that completion of the life cycle leads to antigenic switching.

Meng, T. C.; Hetsko, M. L.; Gillin, F. D.

1993-01-01

78

Unusually Low Levels of Genetic Variation among Giardia lamblia Isolates? ‡  

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Giardia lamblia, an intestinal pathogen of mammals, including humans, is a significant cause of diarrheal disease around the world. Additionally, the parasite is found on a lineage which separated early from the main branch in eukaryotic evolution. The extent of genetic diversity among G. lamblia isolates is insufficiently understood, but this knowledge is a prerequisite to better understand the role of parasite variation in disease etiology and to examine the evolution of mechanisms of genet...

Teodorovic, Smilja; Braverman, John M.; Elmendorf, Heidi G.

2007-01-01

79

Biliary lipids support serum-free growth of Giardia lamblia.  

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Giardia lamblia has been grown in vitro only in media containing serum or serum fractions. How this pathogen can grow in the human small intestinal lumen without serum is not known. We found that samples of human hepatic or gall bladder bile maintained G. lamblia survival for 24 to 48 h in medium without serum but did not support growth. By contrast, an artificial biliary lipid dispersion containing six bile salts, phosphatidylcholine (PC), and cholesterol, in the ratios characteristic of hum...

Gillin, F. D.; Gault, M. J.; Hofmann, A. F.; Gurantz, D.; Sauch, J. F.

1986-01-01

80

Description and characterization of a surface lectin from Giardia lamblia.  

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The mechanisms by which the human enteric pathogen Giardia lamblia colonizes the proximal small intestine are poorly understood. Although the parasite possesses an attachment organelle on its ventral surface, the "sucking" disk, we considered that like many bacteria and some protozoa, G. lamblia might also have a surface membrane-associated modality for adherence to its host. Using an erythrocyte mixed-agglutination model, we demonstrated a parasite surface lectin with specificities for D-glu...

Farthing, M. J.; Pereira, M. E.; Keusch, G. T.

1986-01-01

 
 
 
 
81

Detection of anti-Giardia lamblia serum antibody among children of day care centers / Detecção de anticorpos séricos anti-Giardia lamblia em crianças de creches  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese OBJETIVOS: Detectar anticorpos séricos anti-Giardia lamblia entre crianças atendidas em creches e estimar a freqüência de infecção por Giardia lamblia em área endêmica. MÉTODOS: Foram coletadas três amostras de fezes de cada uma das 147 crianças de três creches da rede municipal de Botucatu, SP, com [...] idade variando de 0 a 6 anos, e as amostras foram processadas pelos métodos de sedimentação espontânea e flutuação pelo sulfato de zinco. Amostras de sangue foram obtidas da polpa digital, coletadas em papel de filtro e testadas pelos métodos de imunofluorescência indireta (IFI) e de reação imunoenzimática (Elisa) para pesquisa de IgG anti-Giardia. RESULTADOS E CONCLUSÕES: De um total de 147 crianças, 93 (63,3%) apresentaram cistos de Giardia nas fezes. Dos 147 eluatos testados, 93 (63,3%) e 100 (68%) foram positivos para Giardia em IFI e em Elisa, respectivamente. A sensibilidade de IFI foi de 82% e de Elisa, 72%. Contudo, Elisa foi menos específica (39%) do que IFI (70%). A imunofluorescência indireta apresentou maior concordância com o exame de fezes do que Elisa. Abstract in english OBJETIVES: To detect anti-Giardia lamblia serum antibodies in healthy children attending public day care centers and to assess serological tests as tools for estimating the prevalence of G. lamblia in endemic areas. METHODS: Three separate stool specimens and filter paper blood samples were collecte [...] d from 147 children ranging from 0 to 6 years old. Each stool sample was processed using spontaneous sedimentation and zinc sulfate flotation methods. Blood samples were tested by indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA) for Giardia IgG. RESULTS AND CONCLUSIONS: Of 147 individuals tested, 93 (63.3%) showed Giardia cysts in their feces. Using IIF and ELISA, serum antibodies were detected in 93 (63.3%) and 100 (68%) samples , respectively. Sensitivity of IIF and ELISA was 82% and 72%, respectively. However, ELISA revealed to be less specific (39%) than IIF (70%). IIF also showed a higher concordance with microscopic examination than ELISA.

Guimarães, Semíramis; Sogayar, Maria Inês L.

82

Detection of anti-Giardia lamblia serum antibody among children of day care centers / Detecção de anticorpos séricos anti-Giardia lamblia em crianças de creches  

Scientific Electronic Library Online (English)

Full Text Available SciELO Public Health | Language: English Abstract in portuguese OBJETIVOS: Detectar anticorpos séricos anti-Giardia lamblia entre crianças atendidas em creches e estimar a freqüência de infecção por Giardia lamblia em área endêmica. MÉTODOS: Foram coletadas três amostras de fezes de cada uma das 147 crianças de três creches da rede municipal de Botucatu, SP, com [...] idade variando de 0 a 6 anos, e as amostras foram processadas pelos métodos de sedimentação espontânea e flutuação pelo sulfato de zinco. Amostras de sangue foram obtidas da polpa digital, coletadas em papel de filtro e testadas pelos métodos de imunofluorescência indireta (IFI) e de reação imunoenzimática (Elisa) para pesquisa de IgG anti-Giardia. RESULTADOS E CONCLUSÕES: De um total de 147 crianças, 93 (63,3%) apresentaram cistos de Giardia nas fezes. Dos 147 eluatos testados, 93 (63,3%) e 100 (68%) foram positivos para Giardia em IFI e em Elisa, respectivamente. A sensibilidade de IFI foi de 82% e de Elisa, 72%. Contudo, Elisa foi menos específica (39%) do que IFI (70%). A imunofluorescência indireta apresentou maior concordância com o exame de fezes do que Elisa. Abstract in english OBJETIVES: To detect anti-Giardia lamblia serum antibodies in healthy children attending public day care centers and to assess serological tests as tools for estimating the prevalence of G. lamblia in endemic areas. METHODS: Three separate stool specimens and filter paper blood samples were collecte [...] d from 147 children ranging from 0 to 6 years old. Each stool sample was processed using spontaneous sedimentation and zinc sulfate flotation methods. Blood samples were tested by indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA) for Giardia IgG. RESULTS AND CONCLUSIONS: Of 147 individuals tested, 93 (63.3%) showed Giardia cysts in their feces. Using IIF and ELISA, serum antibodies were detected in 93 (63.3%) and 100 (68%) samples , respectively. Sensitivity of IIF and ELISA was 82% and 72%, respectively. However, ELISA revealed to be less specific (39%) than IIF (70%). IIF also showed a higher concordance with microscopic examination than ELISA.

Guimarães, Semíramis; Sogayar, Maria Inês L.

83

Detection of anti-Giardia lamblia serum antibody among children of day care centers Detecção de anticorpos séricos anti-Giardia lamblia em crianças de creches  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVES: To detect anti-Giardia lamblia serum antibodies in healthy children attending public day care centers and to assess serological tests as tools for estimating the prevalence of G. lamblia in endemic areas. METHODS: Three separate stool specimens and filter paper blood samples were collected from 147 children ranging from 0 to 6 years old. Each stool sample was processed using spontaneous sedimentation and zinc sulfate flotation methods. Blood samples were tested by indirect immunofluorescence (IIF and enzyme-linked immunosorbent assay (ELISA for Giardia IgG. RESULTS AND CONCLUSIONS: Of 147 individuals tested, 93 (63.3% showed Giardia cysts in their feces. Using IIF and ELISA, serum antibodies were detected in 93 (63.3% and 100 (68% samples , respectively. Sensitivity of IIF and ELISA was 82% and 72%, respectively. However, ELISA revealed to be less specific (39% than IIF (70%. IIF also showed a higher concordance with microscopic examination than ELISA.OBJETIVOS: Detectar anticorpos séricos anti-Giardia lamblia entre crianças atendidas em creches e estimar a freqüência de infecção por Giardia lamblia em área endêmica. MÉTODOS: Foram coletadas três amostras de fezes de cada uma das 147 crianças de três creches da rede municipal de Botucatu, SP, com idade variando de 0 a 6 anos, e as amostras foram processadas pelos métodos de sedimentação espontânea e flutuação pelo sulfato de zinco. Amostras de sangue foram obtidas da polpa digital, coletadas em papel de filtro e testadas pelos métodos de imunofluorescência indireta (IFI e de reação imunoenzimática (Elisa para pesquisa de IgG anti-Giardia. RESULTADOS E CONCLUSÕES: De um total de 147 crianças, 93 (63,3% apresentaram cistos de Giardia nas fezes. Dos 147 eluatos testados, 93 (63,3% e 100 (68% foram positivos para Giardia em IFI e em Elisa, respectivamente. A sensibilidade de IFI foi de 82% e de Elisa, 72%. Contudo, Elisa foi menos específica (39% do que IFI (70%. A imunofluorescência indireta apresentou maior concordância com o exame de fezes do que Elisa.

Semíramis Guimarães

2002-02-01

84

Comparison of Two Target Genes for Detection and Genotyping of Giardia lamblia in Human Feces by PCR and PCR-Restriction Fragment Length Polymorphism  

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A PCR assay targeting the tpi gene was developed to detect and to genotype Giardia lamblia in human feces. Our assay was specific and discriminated between G. lamblia assemblages A and B. G. lamblia cysts isolated from human feces were also analyzed with two previously described PCR-restriction fragment length polymorphism (RFLP) assays, which are based on the detection of tpi or gdh genes. These RFLP analyses distinguished groups I and II within assemblage A or groups III and IV within assem...

2005-01-01

85

Ingestion of Giardia lamblia trophozoites by human mononuclear phagocytes.  

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Mononuclear phagocytes may be important effector cells against Giardia lamblia. Human monocyte-derived macrophages were incubated with G. lamblia trophozoites in 13% heat-inactivated autologous serum. At a G. lamblia/macrophage ratio of 1:1, the number of trophozoites ingested per 100 macrophages ranged from 1 to 12 at 0.5 h and increased for all donors (n = 6) to 10 to 92 at 8 h. Ingestion was confirmed by electron microscopy. Increasing the parasite/phagocyte ratio to 5:1 increased the perc...

Hill, D. R.; Pearson, R. D.

1987-01-01

86

The abundance of sterile transcripts in Giardia lamblia  

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The protozoan parasite Giardia lamblia synthesizes a diverse and surprisingly abundant array of sterile transcripts unable to code for proteins. Random sampling of cDNAs from two evolutionarily divergent Giardia strains indicates that ?20% of cDNAs in the libraries represent polyadenylated sterile transcripts. RNase protection analysis and northern blot hybridization of three sterile transcript loci demonstrated that both the sterile transcript and a complementary mRNA were made in each cas...

Elmendorf, Heidi G.; Singer, Steven M.; Nash, Theodore E.

2001-01-01

87

Transient transfection and expression of firefly luciferase in Giardia lamblia.  

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We have developed a gene transfer system for the protozoan parasite Giardia lamblia. This organism is responsible for many cases of diarrhea worldwide and is considered to be one of the most primitive eukaryotes. Expression of a heterologous gene was detected in this parasite after electroporation with appropriate DNA constructs. We constructed a series of transfection plasmids using flanking sequences of the Giardia glutamate dehydrogenase (GDH) gene to drive expression of the firefly lucife...

Yee, J.; Nash, T. E.

1995-01-01

88

Giardia lamblia infections in B-cell-deficient transgenic mice.  

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In the present study, we infected B-cell (and antibody-)-deficient transgenic mice with the Giardia lamblia clone GS/M-83-H7. These animals were inhibited in intestinal anti-Giardia immunoglobulin A (IgA) production and could not resolve the parasite infection, and antigenic diversification within the respective parasite populations occurred in an unusually slow manner. These findings indicate an important immunological function of local IgA antibodies which promotes antigenic variation of th...

Stager, S.; Muller, N.

1997-01-01

89

Sensitive and Rapid Detection of Giardia lamblia Infection in Pet Dogs using Loop-Mediated Isothermal Amplification  

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Giardia lamblia is recognized as one of the most prevalent parasites in dogs. The present study aimed to establish a loop-mediated isothermal amplification (LAMP) assay for rapid and specific detection of G. lamblia from dogs. The fecal samples were collected and prepared for microscopic analysis, and then the genomic DNA was extracted directly from purified cysts. The concentration of DNA samples of G. lamblia were diluted by 10-fold serially ranging from 10-1 to 10-5 ng/µl for LAMP and PCR...

2013-01-01

90

Comparison of primers and optimization of PCR conditions for detection of Cryptosporidium parvum and Giardia lamblia in water.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Eight pairs of published PCR primers were evaluated for the specific detection of Cryptosporidium parvum and Giardia lamblia in water. Detection sensitivities ranged from 1 to 10 oocysts or cysts for purified preparations and 5 to 50 oocysts or cysts for seeded environmental water samples. Maximum sensitivity was achieved with two successive rounds of amplification and hybridization, with oligonucleotide probes detected by chemiluminescence. Primer annealing temperatures and MgCl2 concentrati...

Rochelle, P. A.; Leon, R.; Stewart, M. H.; Wolfe, R. L.

1997-01-01

91

Efficacies of Zinc-Finger-Active Drugs against Giardia lamblia  

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Twenty-nine of 34 (85%) Zn-finger-active compounds at 300 ?M or less inhibited the growth of Giardia lamblia. The most active compound, disulfiram (Antabuse), was cidal at 1.23 ± 0.32 ?M. In the adult mouse model, significant in vivo activity was demonstrated by increased cure rates and decreased parasite burdens.

Nash, Theodore; Rice, William G.

1998-01-01

92

Azasterols impair Giardia lamblia proliferation and induces encystation  

International Nuclear Information System (INIS)

The effects of sterol biosynthesis inhibitors on growth and fine structure of Giardia lamblia P1 strain cultures were analyzed. Azasterols demonstrated high efficacy in killing cells. The IC50 values for 22,26-azasterol and 24(R,S),25-epiminolanosterol were 7 ?M and 170 nM, respectively. Morphological analysis showed that azasterols induced changes in G. lamblia ultrastructure. The most significant alterations were: (a) considerable increase of the size of the peripheral vesicles, which are part of the parasite endosomal-lysosomal system; (b) appearance of autophagosomal structures; and (c) induction of differentiation, followed by an abnormal enlargement of encystation secretory vesicles. We propose that azasterols are effective chemotherapeutic drugs against Giardia lamblia in vitro and may have another target in cells besides sterol biosynthesis

2007-11-16

93

Giardia Cyst Wall Protein 1 Is a Lectin That Binds to Curled Fibrils of the GalNAc Homopolymer  

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The infectious and diagnostic stage of Giardia lamblia (also known as G. intestinalis or G. duodenalis) is the cyst. The Giardia cyst wall contains fibrils of a unique ?-1,3-linked N-acetylgalactosamine (GalNAc) homopolymer and at least three cyst wall proteins (CWPs) composed of Leu-rich repeats (CWPLRR) and a C-terminal conserved Cys-rich region (CWPCRR). Our goals were to dissect the structure of the cyst wall and determine how it is disrupted during excystation. The intact Giardia cyst w...

Chatterjee, Aparajita; Carpentieri, Andrea; Ratner, Daniel M.; Bullitt, Esther; Costello, Catherine E.; Robbins, Phillips W.; Samuelson, John

2010-01-01

94

Genome ploidy in different stages of the Giardia lamblia life cycle.  

Science.gov (United States)

The early diverging eukaryotic parasite Giardia lamblia is unusual in that it contains two apparently identical nuclei in the vegetative trophozoite stage. We have determined the nuclear and cellular genome ploidy of G. lamblia cells during all stages of the life cycle. During vegetative growth, the nuclei cycle between a diploid (2N) and tetraploid (4N) genome content and the cell, consequently, cycles between 4N and 8N. Stationary phase trophozoites arrest in the G2 phase with a ploidy of 8N (two nuclei, each with a 4N ploidy). On its way to cyst formation, a G1 trophozoite goes through two successive rounds of chromosome replication without an intervening cell division event. Fully differentiated cysts contain four nuclei, each with a ploidy of 4N, resulting in a cyst ploidy of 16N. The newly excysted cell, for which we suggest the term 'excyzoite', contains four nuclei (cellular ploidy 16N). In a reversal of the events occurring during encystation, the excyzoite divides twice to form four trophozoites containing two diploid nuclei each. The formation of multiple cells from a single cyst is likely to be one of the main reasons for the low infectious doses of G. lamblia. PMID:11207620

Bernander, R; Palm, J E; Svärd, S G

2001-01-01

95

Unusual ribosomal RNA of the intestinal parasite Giardia lamblia.  

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The anaerobic protozoan Giardia lamblia is a common intestinal parasite in humans, but is poorly defined at molecular and phylogenetic levels. We report here a structural characterization of the ribosomal RNA (rRNA) and rRNA genes of G. lamblia. Gel electrophoresis under native or non-denaturing conditions identified two high molecular weight rRNA species corresponding to the 16-18S and 23-28S rRNAs. Surprisingly, both species (1300 and 2300 nucleotides long, respectively) were considerably s...

Edlind, T. D.; Chakraborty, P. R.

1987-01-01

96

Cross-species transmission of Giardia spp.: inoculation of beavers and muskrats with cysts of human, beaver, mouse, and muskrat origin.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giardia cysts isolated from humans, beavers, mice, and muskrats were tested in cross-species transmission experiments for their ability to infect either beavers or muskrats. Giardia cysts, derived from multiple symptomatic human donors and used for inoculation of beavers or muskrats, were shown to be viable by incorporation of fluorogenic dyes, excystation, and their ability to produce infections in the Mongolian gerbil model. Inoculation of beavers with 5 x 10(5) Giardia lamblia cysts result...

Erlandsen, S. L.; Sherlock, L. A.; Januschka, M.; Schupp, D. G.; Schaefer, F. W.; Jakubowski, W.; Bemrick, W. J.

1988-01-01

97

FILTRATION OF 'GIARDIA' CYSTS AND OTHER SUBSTANCES. VOLUME 3. RAPID RATE FILTRATION  

Science.gov (United States)

The efficiency of rapid rate filtration for removal of Giardia lamblia cysts, standard plate count bacteria, total coliform bacteria, and turbidity was determined experimentally under a wide range of operating conditions. Percent removal was evaluated by means of a lab-scale pilo...

98

The cytotoxic effects of ciprofloxacin in Giardia lamblia trophozoites  

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The cytotoxicity of ciprofloxacin was investigated in culture of Giardia lamblia (ATCC 30957), used as an in vitro cellular model, on the basis of cell growth, morphology, viability, adherence and metabolic studies. The effects on cell membrane integrity were evaluated by permeability of the cells to trypan blue, and the morphological alterations were studied by optical and transmission electronic microscopy. The metabolic studies were performed by measured oxygen uptake with a Clark-type oxy...

Sousa, M. C.; Poiares-da-silva, J.

2001-01-01

99

Cytotoxicity Induced by Bismuth Subcitrate in Giardia lamblia Trophozoites  

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The cytotoxicity of colloidal bismuth subcitrate (CBS) was investigated in cultured Giardia lamblia trophozoites on the basis of cell attachment, morphology and viability studies. The effects on cell membrane integrity were evaluated by the permeability to trypan blue, and the morphological alterations were studied by phase-contrast microscopy and transmission electron microscopy. Our data show that although CBS induced loss of cellular viability (morphological and regrowth studies), the cell...

Sousa, M. C.; Poiares-da-silva, J.

1999-01-01

100

Antigenic variation in Giardia lamblia and the host's immune response.  

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Giardia lamblia, a protozoan parasite of the small intestine of humans and other animals, undergoes surface antigenic variation. The antigens involved belong to a family of variant-specific surface proteins (VSPs), which are unique, cysteine-rich zinc finger proteins. The patterns of infection in humans and animals fail to show the expected cyclical waves of increasing and decreasing numbers of parasites expressing unique VSPs. Nevertheless, changes in VSP expression occur within the populati...

Nash, T. E.

1997-01-01

 
 
 
 
101

Cloning of two putative Giardia lamblia glucosamine 6-phosphate isomerase genes only one of which is transcriptionally activated during encystment.  

Science.gov (United States)

The biosynthesis of the carbohydrate component of the cyst wall of the protozoan parasite Giardia lamblia, a polymer of N-acetylgalactosamine (GalNac), is by a pathway that is initiated with the conversion of fructose 6-phosphate to glucosamine 6-phosphate by an aminating isomerase, glucose 6-phosphate isomerase. This enzyme appears only after Giardia trophozoites are induced to start the production of cyst wall components after bile is added. To investigate whether induction of glucosamine 6-phosphate isomerase is by protein modification or by transcription activation, its gene was cloned and sequenced. Two genes, gpi1 and gpi2, encoding putative glucosamine 6-phosphate isomerases were identified but one, gpi1 was expressed. The transcript for gpi1 appeared not earlier than 6 h after cells were induced with bile salts. These results show that the first enzyme in the pathway leading to GalNac synthesis in encysting Giardia cyst wall biosynthesis is under transcriptional control. PMID:9864853

Van Keulen, H; Steimle, P A; Bulik, D A; Borowiak, R K; Jarroll, E L

1998-01-01

102

Activity of the anthelmintic benzimidazoles against Giardia lamblia in vitro.  

Science.gov (United States)

In vitro growth of the protozoan parasite Giardia lamblia was highly sensitive to certain anthelmintic benzimidazoles. Albendazole and mebendazole were 30- to 50-fold more active than metronidazole and 4- to 40-fold more active than quinacrine. Thiabendazole, a noncarbamate benzimidazole, was less active. Since lack of intestinal absorption makes mebendazole an attractive new antigiardial agent, its in vitro activity was further characterized. At low concentrations (0.05 micrograms/ml) mebendazole had a static effect on G. lamblia growth; however, lethal activity was observed at a concentration fivefold lower (0.3 micrograms/ml) than necessary for the cidal agent metronidazole. Two observations are consistent with a microtubule target for mebendazole. First, attachment of cells to the culture tube, mediated by the ventral disk and flagella, was rapidly disrupted by mebendazole treatment. Second, the characteristic cell structure was grossly distorted by treatment. No mebendazole-resistant G. lamblia were detected in a population of 10(8) cells. PMID:2230276

Edlind, T D; Hang, T L; Chakraborty, P R

1990-12-01

103

CYTOCHEMICAL METHODS FOR ASSESSING 'GIARDIA' CYST VIABILITY  

Science.gov (United States)

Giardia lamblia is the most common human intestinal protozoan parasite reported in the United States and England. The objective of the study was to develop a practical, reliable, rapid, microscopically-read method, comparable to excystation for determining the viability of Giardi...

104

Quantitation of Giardia cysts by membrane filtration.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A method of fixing and staining Giardia cysts on a membrane filter is reported. This procedure appears to be a reliable method for the recovery and detection of cysts and also for the determination of cyst densities. Evaluation and possible applications of the technique are described.

1983-01-01

105

Genomic minimalism in the early diverging intestinal parasite Giardia lamblia.  

Science.gov (United States)

The genome of the eukaryotic protist Giardia lamblia, an important human intestinal parasite, is compact in structure and content, contains few introns or mitochondrial relics, and has simplified machinery for DNA replication, transcription, RNA processing, and most metabolic pathways. Protein kinases comprise the single largest protein class and reflect Giardia's requirement for a complex signal transduction network for coordinating differentiation. Lateral gene transfer from bacterial and archaeal donors has shaped Giardia's genome, and previously unknown gene families, for example, cysteine-rich structural proteins, have been discovered. Unexpectedly, the genome shows little evidence of heterozygosity, supporting recent speculations that this organism is sexual. This genome sequence will not only be valuable for investigating the evolution of eukaryotes, but will also be applied to the search for new therapeutics for this parasite. PMID:17901334

Morrison, Hilary G; McArthur, Andrew G; Gillin, Frances D; Aley, Stephen B; Adam, Rodney D; Olsen, Gary J; Best, Aaron A; Cande, W Zacheus; Chen, Feng; Cipriano, Michael J; Davids, Barbara J; Dawson, Scott C; Elmendorf, Heidi G; Hehl, Adrian B; Holder, Michael E; Huse, Susan M; Kim, Ulandt U; Lasek-Nesselquist, Erica; Manning, Gerard; Nigam, Anuranjini; Nixon, Julie E J; Palm, Daniel; Passamaneck, Nora E; Prabhu, Anjali; Reich, Claudia I; Reiner, David S; Samuelson, John; Svard, Staffan G; Sogin, Mitchell L

2007-09-28

106

Development of functional gastrointestinal disorders after Giardia lamblia infection  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Functional gastrointestinal disorders (FGID may occur following acute gastroenteritis. This long-term complication has previously not been described after infection with the non-invasive protozoan Giardia lamblia. This study aims to characterize persistent abdominal symptoms elicited by Giardia infection according to Rome II criteria and symptoms scores. Methods Structured interview and questionnaires 12–30 months after the onset of Giardia infection, and at least 6 months after Giardia eradication, among 82 patients with persisting abdominal symptoms elicited by the Giardia infection. All had been evaluated to exclude other causes. Results We found that 66 (80.5% of the 82 patients had symptoms consistent with irritable bowel syndrome (IBS and 17 (24.3% patients had functional dyspepsia (FD according to Rome II criteria. IBS was sub classified into D-IBS (47.0%, A-IBS (45.5% and C-IBS (7.6%. Bloating, diarrhoea and abdominal pain were reported to be most severe. Symptoms exacerbation related to specific foods were reported by 45 (57.7% patients and to physical or mental stress by 34 (44.7% patients. Conclusion In the presence of an IBS-subtype pattern consistent with post-infectious IBS (PI-IBS, and in the absence of any other plausible causes, we conclude that acute Giardia infection may elicit functional gastrointestinal diseases with food and stress related symptoms similar to FGID patients in general.

Hanevik Kurt

2009-04-01

107

Rapid and sensitive detection of Giardia lamblia using a piezoelectric cantilever biosensor in finished and source waters.  

Science.gov (United States)

The current method for detecting the waterborne parasite Giardia lamblia is tedious and requires a preconcentration step. We show for the first time a piezoelectric-excited millimeter-sized cantilever (PEMC) biosensor immobilized with a monoclonal antibody against G. lamblia that exhibits selective and sensitive detection of G. lamblia cysts in several water matrixes (buffer, tap, and river water) at a detection limit of 1-10 cysts/mL without a preconcentration step. The PEMC sensor is a resonance-based device that functions at a high-order mode near 1 MHz. The antibody-immobilized sensor was exposed to 1-10,000 G. lamblia cysts/mL samples in a flow arrangement. When the cysts bind to the antibody on the sensor, the resonant frequency of the cantilever sensor decreases and is recorded continuously. Positive confirmation of sensor detection responses was obtained by environmental scanning electron microscope of sensor surface after detection experiments. Higher sample flow rates (0.5-5.0 mL/min) gave higher sensor detection response. Detecting as few as 10 cysts per mL was achieved in all three water matrixes tested, and significant sensor response was obtained in 15 min. We also show the feasibility of analyzing at a low concentration of 1 cyst/mL in a one liter sample at a high flow rate of 5 mL/min. PMID:20121270

Xu, Sen; Mutharasan, Raj

2010-03-01

108

Freqüência de Giardia lamblia em cães atendidos em clínicas veterinárias de Porto Alegre, RS, Brasil Frequency of Giardia lamblia in dogs attended by veterinary clinics in Porto Alegre city, RS, Brazil  

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Full Text Available A pesquisa de cistos de Giardia lamblia em fezes de cães oriundos de clínicas veterinárias de Porto Alegre, RS, Brasil, foi realizada pelo método de FAUST et al. (1939. Das 526 amostras analisadas, 38% (198 foram positivas para cistos de G. lamblia, sendo 22% (116 constituídos por animais menores de 11 meses de idade e 16% (82 constituídos por animais com 12 meses ou mais de idade. Houve diferença significativa (pThe method of Faust et al. (1939 was utilized for detection of Giardia lamblia cysts in feces from dogs in Porto Alegre city, Rio Grande Sul State, Brazil. From the 526 analyzed samples 38% (198 showed positive results for the presence of G. lamblia cyst, so 22% (116 belonged to group one, formed by animals that were less than eleven months old; and 16% (82 belonged to group two, formed by animals that were twelve months or older. There was a significant difference (p<0,05 among the two groups checked by the c² test. From the animals researched, 54% (285 were male dogs and from these 20% (104 presented cysts in their feces. From the other 46% (241, which were female dogs, 18% (95 presented positive results for the cysts of G. lamblia in their sample. The c² test applied to these data showed that there was not any significant difference between the results found in female or male dogs of all ages. Based on these results, we can come to the conclusion that 38% of the analyzed dogs showed positive results for the infection of G. lamblia and that the younger animals those aged less than eleven months presented a rate of risk to get infected which is two times bigger than the ones for the animals with 12 months or older, as well as, the fact that the sex of the animals did not present any association to the positive results of infection.

Adriane Bartmann

2004-08-01

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Visualization of chromosomes in the binucleate intestinal parasite Giardia lamblia.  

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Mitosis of Giardia lamblia is a complex and rapid event that is poorly understood at the cellular and molecular levels. Therefore, we conducted this study to determine (1) whether the two nuclei have similar or different chromosomes, (2) the number of chromosomes of G. lamblia, and (3) the morphology and karyotype of the chromosomes. Trophozoites of the C2 and WB strains of G. lamblia were grown in modified TYI-S-33 medium at 37°C. The trophozoites were collected, and sample slides were prepared for conventional light and scanning electron microscopy. Light microscopy revealed five pairs of chromosomes. The chromosomes were approximately 0.64-0.94 ?m long with a short rod-like shape and were usually arranged in pairs. Scanning electron microscopy yielded similar findings, and 10 chromosomes could be seen in each nucleus. Thus, the chromosome number of G. lamblia is 2n = 10. Chromosomes in pair 1 are submetacentric chromosomes, while pairs 2-5 are telocentric chromosomes. The present study shows that G. lamblia trophozoites have typical condensed chromosomes during mitosis and contains five pairs of chromosomes. The karyogram shows good fit to the formula 2n = 10 = 2sm + 8t revealed by scanning electron microscopy. PMID:21526404

Shen, Hai E; Cao, Lei; Li, Ji; Tian, Xi Feng; Yang, Zhi Hong; Wang, Yue; Tian, Yu Na; Lu, Si Qi

2011-11-01

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Comparison of microscopy, rapid immunoassay, and molecular techniques for the detection of Giardia lamblia and Cryptosporidium parvum.  

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Giardia lamblia and Cryptosporidium parvum are recognized as the most common protozoan infections in Saudi Arabia. Microscopic examination of stool samples, either direct or concentrated, for the recovery of G. lamblia cysts and trophozoites and C. parvum oocysts is still the most commonly used for the diagnosis of both parasites. We compared the conventional parasitological techniques of iodine-stained wet mount for G. lamblia and Kinyoun's acid-fast for C. parvum against ImmunoCard STAT® Cryptosporidium/Giardia and real-time polymerase chain reaction (PCR) detecting the 18S rRNA gene of G. lamblia and conventional PCR detecting the same gene of C. parvum at a tertiary hospital in Dhahran, Saudi Arabia. Out of 148 stool samples, 19 and 12 true positives were identified for G. lamblia and C. parvum, respectively, using a composite reference standard. In this case, true positives and negatives were considered as those with at least two positive or negative results out of the three tests. Both ImmunoCard STAT! and PCR methods were more sensitive than the microscopic tests of a single stool specimen of 85.7% (CI=62.6-96.2%) and 85.7% (CI=56.2-97.5%) for G. lamblia and C. parvum, respectively. However, specificity of microscopic tests was higher than other techniques for both parasites. Although PCR seems to be most sensitive for both G. lamblia and C. parvum, its low specificity may render its superiority over other techniques. When a single stool sample is used for detection of G. lamblia and C. parvum, better results can be obtained when coupled with serological testing. Although PCR is the most sensitive method for the detection of both G. lamblia and C. parvum, its use requires attention in relation to the increased possible false positives. PMID:23411740

Elsafi, Salah H; Al-Maqati, Thekra N; Hussein, Mohi I; Adam, Ahmed A; Hassan, Mohamed M Abu; Al Zahrani, Eidan M

2013-04-01

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A sphingolipid inhibitor induces a cytokinesis arrest and blocks stage differentiation in Giardia lamblia.  

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Sphingolipid biosynthesis pathways have recently emerged as a promising target for therapeutic intervention against pathogens, including parasites. A key step in the synthesis of complex sphingolipids is the glucosylation of ceramide, mediated by glucosylceramide (GlcCer) synthase, whose activity can be inhibited by PPMP (1-phenyl-2-palmitoylamino-3-morpholino-1-propanol). In this study, we investigated whether PPMP inhibits the proliferation and differentiation of the pathogenic parasite Giardia lamblia, the major cause of parasite-induced diarrhea worldwide. PPMP was found to block in vitro parasite replication in a dose-dependent manner, with a 50% inhibitory concentration of 3.5 muM. The inhibition of parasite replication was irreversible at 10 muM PPMP, a concentration that did not affect mammalian cell metabolism. Importantly, PPMP inhibited the completion of cell division at a specific stage in late cytokinesis. Microscopic analysis of cells incubated with PPMP revealed the aberrant accumulation of cellular membranes belonging to the endoplasmic reticulum network in the caudal area of the parasites. Finally, PPMP induced a 90% reduction in G. lamblia differentiation into cysts, the parasite stage responsible for the transmission of the disease. These results show that PPMP is a powerful inhibitor of G. lamblia in vitro and that as-yet-uncharacterized sphingolipid biosynthetic pathways are potential targets for the development of anti-G. lamblia agents. PMID:18086854

Sonda, Sabrina; Stefanic, Sasa; Hehl, Adrian B

2008-02-01

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Unusual ribosomal RNA of the intestinal parasite Giardia lamblia.  

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The anaerobic protozoan Giardia lamblia is a common intestinal parasite in humans, but is poorly defined at molecular and phylogenetic levels. We report here a structural characterization of the ribosomal RNA (rRNA) and rRNA genes of G. lamblia. Gel electrophoresis under native or non-denaturing conditions identified two high molecular weight rRNA species corresponding to the 16-18S and 23-28S rRNAs. Surprisingly, both species (1300 and 2300 nucleotides long, respectively) were considerably shorter than their counterparts from other protozoa (typically 1800 and 3400 nucleotides), and from bacteria as well (typically 1540 and 2900 nucleotides long). Denaturing polyacrylamide gel electrophoresis identified a major low molecular RNA of 127 nucleotides and several minor species, but no molecules with the typical lengths of 5.8S (160 nucleotides) and 5S (120 nucleotides) rRNA. The G. lamblia 1300, 2300, and 127 nucleotide RNAs are encoded within a 5.6 kilobase pair tandemly repeated DNA, as shown by Southern blot analysis and DNA cloning. Thus, the rRNA operon of this eukaryotic organism can be no longer than a typical bacterial operon. Sequence analysis identified the 127 nucleotide RNA as homologous to 5.8S RNA, but comparisons to archaebacterial rRNA suggest that Giardia derived from an early branch in eukaryotic evolution. PMID:3118329

Edlind, T D; Chakraborty, P R

1987-10-12

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Role of nitric oxide and superoxide in Giardia lamblia killing  

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Full Text Available Giardia lamblia trophozoites were incubated for 2 h with activated murine macrophages, nitric oxide (NO donors or a superoxide anion generator (20 mU/ml xanthine oxidase plus 1 mM xanthine. Activated macrophages were cytotoxic to Giardia trophozoites (~60% dead trophozoites. This effect was inhibited (>90% by an NO synthase inhibitor (200 µM and unaffected by superoxide dismutase (SOD, 300 U/ml. Giardia trophozoites were killed by the NO donors, S-nitroso-acetyl-penicillamine (SNAP and sodium nitroprusside (SNP in a dose-dependent manner (LD50 300 and 50 µM, respectively. A dual NO-superoxide anion donor, 3-morpholino-sydnonimine hydrochloride (SIN-1, did not have a killing effect in concentrations up to 1 mM. However, when SOD (300 U/ml was added simultaneously with SIN-1 to Giardia, a significant trophozoite-killing effect was observed (~35% dead trophozoites at 1 mM. The mixture of SNAP or SNP with superoxide anion, which yields peroxynitrite, abolished the trophozoite killing induced by NO donors. Authentic peroxynitrite only killed trophozoites at very high concentrations (3 mM. These results indicate that NO accounts for Giardia trophozoite killing and this effect is not mediated by peroxynitrite

Fernandes P.D.

1997-01-01

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Role of nitric oxide and superoxide in Giardia lamblia killing  

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Full Text Available SciELO Brazil | Language: English Abstract in english Giardia lamblia trophozoites were incubated for 2 h with activated murine macrophages, nitric oxide (NO) donors or a superoxide anion generator (20 mU/ml xanthine oxidase plus 1 mM xanthine). Activated macrophages were cytotoxic to Giardia trophozoites (~60% dead trophozoites). This effect was inhib [...] ited (>90%) by an NO synthase inhibitor (200 µM) and unaffected by superoxide dismutase (SOD, 300 U/ml). Giardia trophozoites were killed by the NO donors, S-nitroso-acetyl-penicillamine (SNAP) and sodium nitroprusside (SNP) in a dose-dependent manner (LD50 300 and 50 µM, respectively). A dual NO-superoxide anion donor, 3-morpholino-sydnonimine hydrochloride (SIN-1), did not have a killing effect in concentrations up to 1 mM. However, when SOD (300 U/ml) was added simultaneously with SIN-1 to Giardia, a significant trophozoite-killing effect was observed (~35% dead trophozoites at 1 mM). The mixture of SNAP or SNP with superoxide anion, which yields peroxynitrite, abolished the trophozoite killing induced by NO donors. Authentic peroxynitrite only killed trophozoites at very high concentrations (3 mM). These results indicate that NO accounts for Giardia trophozoite killing and this effect is not mediated by peroxynitrite

P.D., Fernandes; J., Assreuy.

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The abundance of sterile transcripts in Giardia lamblia.  

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The protozoan parasite Giardia lamblia synthesizes a diverse and surprisingly abundant array of sterile transcripts unable to code for proteins. Random sampling of cDNAs from two evolutionarily divergent Giardia strains indicates that approximately 20% of cDNAs in the libraries represent polyadenylated sterile transcripts. RNase protection analysis and northern blot hybridization of three sterile transcript loci demonstrated that both the sterile transcript and a complementary mRNA were made in each case, further categorizing these sterile transcripts as antisense transcripts. Investigation of the genomic loci for these same three sterile antisense transcripts showed typical transcription units for the sense transcripts, but still failed to reveal a usable open reading frame for the sterile antisense transcripts. 5'-RACE mapped the transcription start site for one of the sterile antisense transcripts to an AT-rich region, as is typical for GIARDIA: It is unclear whether these sterile transcripts represent errors in transcription or whether they have regulatory functions within the cell, although preliminary investigations failed to reveal evidence for a role in developmental gene regulation. In either case, the presence of such a large pool of sterile antisense transcripts is dramatic evidence of the unusual molecular machinery of the early diverging protist G.lamblia. PMID:11713317

Elmendorf, H G; Singer, S M; Nash, T E

2001-11-15

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The Study of the Multilayer Filtration Process Efficiency on Giardia lamblia Elimination in Isfahan Water Treatment Plant  

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Full Text Available Introduction: Giardia lamblia is a waterborne highly infectious protozoan parasite capable of causing gastrointestinal illness. The multilayer filtration is used in many applications such as turbidity removes from surface waters and Bacteria, Viruses and protozoan removes. This study was investigated in full-scale the efficiency of filtration process during water treatment that remove Giardia cyst in water at Isfahan province. Materials and methods: We used Information Collection Rule method (ICR. In this method the polypropylene yarn-wound cartridge filter for isolation of these parasites was examined and followed by elution, sample concentration, flotation by percoll-sucrose solution and immunofluorescence antibody (IFA staining to recognize them. Results: Result showed that three layer filtration had a maximum 2.3 log10 for remove Giardia cyst. Cysts removal in water filtration is likely to be comparable to the efficiency of turbidity. Efficiency removal was 99.5% for Giardia and 92.7% for turbidity in filtration stage. We detected 0.2 cyst per 100 liter and per 100 liter in filtered water. This observation is according to U.S.EPA standards. The number of cysts were more in high pH samples. Discussion and conclusion: Analysis of physical processes of treatment water in Isfahan plant configurations showed that granular filters (include sand, anthracite and garnet filter were more likely to have effluence in removal cysts than dual filters.

Zahra Mosaviyan

2014-04-01

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Estudio de factores asociados con la reinfección por Giardia lamblia en niños de círculos infantiles  

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El protozoo Giardia lamblia, también conocido como Giardia duodenalis o Giardia intestinalis, es un parásito del intestino delgado que puede causar alta morbilidad tanto en países desarrollados como en los subdesarrollados. La infección por G. lamblia es más prevalente en niños de 1 a 5 años de edad, en especial aquellos que asisten a círculos infantiles. Teniendo en cuenta la alta frecuencia que puede alcanzar la infección por este protozoo en estas instituciones educacionales, y co...

Nu?n?ez Ferna?ndez, Fidel Angel

2005-01-01

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Putative telomerase catalytic subunits from Giardia lamblia and Caenorhabditis elegans.  

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Eukaryotic chromosomes end in short nucleotide repeats that are added by the enzyme telomerase. The catalytic subunit of telomerase has been shown to be most closely related in sequence to reverse transcriptases encoded by eukaryotic retrotransposable elements. This raises the question as to whether the telomerase subunit was present in the first eukaryotes or was derived during early eukaryote evolution from the replication machinery of a retrotransposable element. We present the sequence of a putative telomerase catalytic subunit from the diplomonad parasite, Giardia lamblia. The G. lamblia subunit appears to have most of the characteristics of other sequenced telomerases, except that it lacks the conserved telomerase-specific 'T' motif previously identified in other eukaryotic genes. Searching genomic databases with the G. lamblia sequence, we also identified a potential telomerase catalytic subunit from Caenorhabditis elegans. The C. elegans subunit is uncharacteristically short, and lacks several motifs found in all other telomerases. The identification of a G. lamblia telomerase similar to that of most other eukaryotes suggests that telomerase dates back to the earliest extant marker of eukaryotic evolution. The atypical C. elegans telomerase, on the other hand, raises intriguing biochemical questions concerning sub-domains of the telomerase catalytic subunit previously considered indispensable. The enzymatic machinery for telomere formation in C. elegans is likely to differ substantially from that of other eukaryotes. PMID:10876087

Malik, H S; Burke, W D; Eickbush, T H

2000-06-27

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Freqüência de Giardia lamblia em cães atendidos em clínicas veterinárias de Porto Alegre, RS, Brasil / Frequency of Giardia lamblia in dogs attended by veterinary clinics in Porto Alegre city, RS, Brazil  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A pesquisa de cistos de Giardia lamblia em fezes de cães oriundos de clínicas veterinárias de Porto Alegre, RS, Brasil, foi realizada pelo método de FAUST et al. (1939). Das 526 amostras analisadas, 38% (198) foram positivas para cistos de G. lamblia, sendo 22% (116) constituídos por animais menores [...] de 11 meses de idade e 16% (82) constituídos por animais com 12 meses ou mais de idade. Houve diferença significativa (p Abstract in english The method of Faust et al. (1939) was utilized for detection of Giardia lamblia cysts in feces from dogs in Porto Alegre city, Rio Grande Sul State, Brazil. From the 526 analyzed samples 38% (198) showed positive results for the presence of G. lamblia cyst, so 22% (116) belonged to group one, formed [...] by animals that were less than eleven months old; and 16% (82) belonged to group two, formed by animals that were twelve months or older. There was a significant difference (p

Adriane, Bartmann; Flávio Antônio Pacheco de, Araújo.

120

Antigenic variation and the murine immune response to Giardia lamblia.  

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The protozoan parasite Giardia lamblia is an important causative agent of acute or chronic diarrhoea in humans and various animals. During infection, the parasite survives the host's reactions by undergoing continuous antigenic variation of its major surface antigen, named VSP (variant surface protein). The VSPs form a unique family of cysteine-rich proteins that are extremely heterogeneous in size. The relevance of antigenic variation for the survival in the host has been most successfully studied by performing experimental infections in a combined mother/offspring mouse system and by using the G. lamblia clone GS/M-83-H7 (human isolate) as model parasite. In-vivo antigenic variation of G. lamblia clone GS/M-83-H7 is characterised by a diversification of the intestinal parasite population into a complex mixture of different variant antigen types. It could be shown that maternally transferred lactogenic anti-VSP IgA antibodies exhibit cytotoxic activity on the Giardia variant-specific trophozoites in suckling mice, and thus express a modulatory function on the proliferative parasite population characteristics. Complementarily, in-vitro as well as in-vivo experiments in adult animals indicated that non-immunological factors such as intestinal proteases may interfere into the process of antigen variation in that they favour proliferation of those variant antigen-type populations which resist the hostile physiological conditions within the intestine. These observations suggest that an interplay between immunological and physiological factors, rather than one of these two factor alone, modulates antigenic diversification of a G. lamblia population within an experimental murine host and thus influences the survival rate and strategy of the parasite. PMID:9925261

Müller, N; Gottstein, B

1998-12-01

 
 
 
 
121

Flagellar generated flow mediates attachment of Giardia Lamblia  

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Giardia lamblia is a protozoan parasite responsible for widespread diarrheal disease in humans and animals worldwide. Attachment to the host intestinal mucosa and resistance to peristalsis is necessary for establishing infection, but the physical basis for this attachment is poorly understood. We report results from confocal fluorescence microscopy that demonstrate that the regular beating of the posterior flagella generate a flow through the ventral disk, a suction-cup shaped structure that is against the substrate during attachment. Finite element simulations show that the negative pressure generated by the flow is consistent with the measured force of attachement between the parasite and its substrate.

Picou, Theodore; Polackwich, Jamie; Burrola Gabilondo, Beatriz; McAllister, Ryan; Powers, Tom; Elmendorf, Heidi; Urbach, Jeff

2011-11-01

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Cholate-dependent killing of Giardia lamblia by human milk.  

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We showed previously that nonimmune human milk (NHM) kills Giardia lamblia trophozoites in vitro and presented evidence that killing requires the bile salt-stimulated lipase of milk. Since this enzyme is activated by bile salts, killing should be dependent on the presence of bile salts. We now show that killing by fresh NHM or NHM stored at -70 degrees C is totally dependent on sodium cholate (a bile salt). With less than 0.4 mM cholate, no parasites were killed, whereas with 1 mM cholate, gr...

1985-01-01

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Detection of a Giardia lamblia coproantigen by using a commercially available immunoenzymatic assay, in Belo Horizonte, Brazil  

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Full Text Available It is known that fecal examination to detect Giardia lamblia cysts or trophozoites produces a high percentage of false-negative results. A commercially available immunoenzymatic assay (ProSpecT Giardia Microplate Assay, Alexon, Inc., BIOBRÁS to detect G. lamblia specific coproantigen was evaluated for the first time in Brazil. A total of 90 specimens were tested. Each specimen was first tested as unpreserved stool, and then it was preserved in 10% Formalin to be tested 2 months later. The assay was able to identify all the 30 positive patients (sensitivity = 100.0% by visual or spectrophotometric examination in the unpreserved specimens and was negative in 57 of the 60 patients without G. lamblia (specificity = 95.0%. The assay identified 27 of the 30 positive patients (sensitivity = 90.0% and was negative in 59 of the 60 negatives (specificity = 98.3% in the preserved stools according to both readings. A marked difference was observed in the optical densities in both groups, preserved and unpreserved stools, when the G. lamblia-positive specimens were compared to the negative or positive for other intestinal parasites than G. lamblia. The assay seems a good alternative for giardiasis diagnosis, especially when the fecal examination was repeatedly negative and the patient presents giardiasislike symptoms.

ROCHA Míriam Oliveira e

1999-01-01

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Actividad lactásica en niños con enfermedad diarreica por Giardia lamblia  

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Full Text Available Se realizó un estudio prospectivo, de corte transversal y analítico, con el propósito de establecer posibles diferencias en el comportamiento de la actividad lactásica en niños menores de 2 años con enfermedad diarreica por Giardia lamblia tratados en el Servicio de Diarreas del Hospital Pediátrico Docente "Dr. Ángel A. Aballí", en el período de diciembre de 1994 a noviembre de 1995. Se determinaron los niveles de la actividad enzimática según diferentes categorías de variables de caracterización del niño y su enfermedad. Los resultados permitieron afirmar su reducción en estos niños, y que tal actividad tiene un comportamiento diferencial asociado con la edad, estado nutricional y grado de atrofia de la mucosa.A prospective analytical cross-sectional study was made with the objective of setting likely differences in Beta-galactosidase performance in under 2 years-old children admitted with diarrheal disease due to Giardia lamblia to «Ángel A. Aballí» Teaching Pediatric Hospital’s Diarrhea Service Unit from December 1994 to November 1995. Levels of the enzime activity were determined according to the several characterization variable categories of the child and his disease. The outcome showed the decline in diarrheal disease in thesechildren and the different performance patterns of this enzime depending on age, nutrition and mucosa atrophic level.

Arnaldo Izquierdo Estévez

1998-03-01

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Cryptosporidium Parvum y Giardia Lamblia en aguas crudas y tratadas del estado Bolívar, Venezuela / CRYPTOSPORIDIUM PARVUM AND GIARDIA LAMBLIA IN RAW AND TREATED WATERS OF THE BOLIVAR STATE  

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Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Se identificó la presencia de Cryptosporidium parvum y Giardia lamblia en aguas de consumo humano antes y después del tratamiento físico-químico y en pozos profundos del estado Bolívar, utilizando el método de inmunofluorescencia con anticuerpos monoclonales (MeriFluor C/G® (Meridian Diagnostic, Inc [...] ) para Cryptosporidium parvum y Giardia y el método de tinción tricrómica para Microsporidium spp. Se demostró Cryptosporidium parvum (28,57%) y Giardia lamblia (23,81%) antes de tratamiento de las aguas y 14,2% de ambos protozoarios después del tratamiento. Ninguna muestra evidenció Microsporidium spp. Sólo uno de los pozos de agua presentó C. parvum (4,76%). Se concluye que Cryptosporidium parvum y Giardia lamblia son resistentes al tratamiento físico-químico de las aguas, lo cual constituye un riesgo para las personas que utilicen esas fuentes. Abstract in english The presence of Cryptosporidium Parvum and Giardia Lamblia was found in human drinking water before and after physical-chemical treatment in deep wells of the Bolívar State using the immunofluorescence method with monoclonal antibodies (MeriFluor C/G ® (Meridian Diagnostic, Inc) for Cryptosporidium [...] Parvum and Giardia, and the trichromic stain method for Microsporidium spp. The presence of Cryptosporidium Parvum (28.57%) and Giardia Lamblia (23.81%) was detected before the treatment of the water, and 14.2% of both protozoa after the treatment. No evidence of Microsporidium spp was found. Only one of the water wells revealed C. Parvum (4.76%). It is concluded that the Cryptosporidium Parvum and Giardia Lamblia are resistant to the physical-chemical treatment of the waters which constitutes a risk factor for the people using these sources.

Julman, Cermeño; Jewel, Arenas; Neyla, Yori; Isabel, Hernández.

126

A Homogenous Luminescence Assay Reveals Novel Inhibitors for Giardia Lamblia Carbamate Kinase  

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The human pathogen Giardia lamblia is an anaerobic protozoan parasite that causes giardiasis, one of the most common diarrheal diseases worldwide. Although several drugs are available for the treatment of giardisis, resistance to these drugs has been reported and is likely to increase. The Giardia carbamate kinase (glCK) plays an essential role in Giardia metabolism and has no homologs in humans, making it an attractive candidate for anti-Giardia drug development. We have developed a luminesc...

Chen, Catherine Z.; Southall, Noel; Galkin, Andrey; Lim, Kap; Marugan, Juan J.; Kulakova, Liudmila; Shinn, Paul; Leer, Danielle; Zheng, Wei; Herzberg, Osnat

2012-01-01

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Detection of Giardia lamblia Antigens in Human Fecal Specimens by a Solid-Phase Qualitative Immunochromatographic Assay?  

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The SIMPLE-READ Giardia rapid assay (Medical Chemical Corporation) is a solid-phase qualitative immunochromatographic assay that detects Giardia lamblia in aqueous extracts of human fecal specimens. Testing 106 Giardia-positive and 104 Giardia-negative stool specimens yielded a sensitivity of 97.2% and a specificity of 100% for the SIMPLE-READ Giardia rapid assay.

Garcia, Lynne S.; Garcia, John Paul

2006-01-01

128

Sensitive and Rapid Detection of Giardia lamblia Infection in Pet Dogs using Loop-Mediated Isothermal Amplification  

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Giardia lamblia is recognized as one of the most prevalent parasites in dogs. The present study aimed to establish a loop-mediated isothermal amplification (LAMP) assay for rapid and specific detection of G. lamblia from dogs. The fecal samples were collected and prepared for microscopic analysis, and then the genomic DNA was extracted directly from purified cysts. The concentration of DNA samples of G. lamblia were diluted by 10-fold serially ranging from 10-1 to 10-5 ng/µl for LAMP and PCR assays. The LAMP assay allows the amplification to be finished within 60 min under isothermal conditions of 63? by employing 6 oligonucleotide primers designed based on G. lamblia elongation factor 1 alpha (EF1?) gene sequence. Our tests showed that the specific amplification products were obtained only with G. lamblia, while no amplification products were detected with DNA of other related protozoans. Sensitivity evaluation indicated that the LAMP assay was sensitive 10 times more than PCR. It is concluded that LAMP is a rapid, highly sensitive and specific DNA amplification technique for detection of G. lamblia, which has implications for effective control and prevention of giardiasis.

Li, Jie; Wang, Peiyuan; Zhang, Aiguo; Zhang, Ping; Alsarakibi, Muhamd

2013-01-01

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Transient transfection and expression of firefly luciferase in Giardia lamblia.  

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We have developed a gene transfer system for the protozoan parasite Giardia lamblia. This organism is responsible for many cases of diarrhea worldwide and is considered to be one of the most primitive eukaryotes. Expression of a heterologous gene was detected in this parasite after electroporation with appropriate DNA constructs. We constructed a series of transfection plasmids using flanking sequences of the Giardia glutamate dehydrogenase (GDH) gene to drive expression of the firefly luciferase reporter gene. The optimal construct consisted of a GDH/luciferase fusion gene in which the first 18 codons of the GDH gene immediately preceded the luciferase gene; this fusion gene was flanked by the upstream and downstream sequences of the GDH gene. Electroporation of this construct into Giardia yielded luciferase activity that was 3000- to 50,000-fold above background. Removal of either the 5' or 3' GDH flanking sequences from this construct resulted in significantly reduced luciferase activity, and removal of both flanking sequences reduced luciferase activity to background levels. Luciferase activity was proportional to the amount of DNA electroporated and was maximal at 6 hr after electroporation. PMID:7777558

Yee, J; Nash, T E

1995-06-01

130

Active and passive mechanisms drive secretory granule biogenesis during differentiation of the intestinal parasite Giardia lamblia.  

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The parasitic protozoan Giardia lamblia undergoes important changes to survive outside the intestine of its host by differentiating into infective cysts. During encystation, three cyst wall proteins (CWPs) are specifically expressed and concentrated within encystation-specific secretory vesicles (ESVs). ESVs are electron-dense secretory granules that transport CWPs before exocytosis and extracellular polymerization into a rigid cyst wall. Because secretory granules form at the trans-Golgi in higher eukaryotes and because Giardia lacks an identifiable Golgi apparatus, the aim of this work was to investigate the molecular basis of secretory granule formation in Giardia by examining the role of CWPs in this process. Although CWP1, CWP2, and CWP3 are structurally similar in their 26-kDa leucine-rich overlapping region, CWP2 is distinguished by the presence of a 13-kDa C-terminal basic extension. In non-encysting trophozoites, expression of different CWP chimeras showed that the CWP2 basic extension is necessary for biogenesis of ESVs, which occurs in a compartment derived from the endoplasmic reticulum. Nevertheless, the CWP2 basic extension per se is insufficient to trigger ESV formation, indicating that other domains in CWPs are also required. We found that CWP2 is a key regulator of ESV formation by acting as an aggregation factor for CWP1 and CWP3 through interactions mediated by its conserved region. CWP2 also acts as a ligand for sorting via its C-terminal basic extension. These findings show that granule biogenesis requires complex interactions among granule components and membrane receptors. PMID:16611634

Gottig, Natalia; Elías, Eliana V; Quiroga, Rodrigo; Nores, María J; Solari, Alberto J; Touz, María C; Luján, Hugo D

2006-06-30

131

Routine in vitro cultivation of Giardia lamblia by using the string test.  

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In vitro axenic cultures of Giardia lamblia were successfully established in 14 successive subjects by a method employing the string test (Entero-Test) for obtaining samples of fluid from the proximal small intestine. This method is applicable to isolating G. lamblia from unselected subjects, including asymptomatic carriers, children, and individuals in diverse or remote geographic regions.

Korman, S. H.; Hais, E.; Spira, D. T.

1990-01-01

132

Quantum Dots as a Novel Immunofluorescent Detection System for Cryptosporidium parvum and Giardia lamblia  

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Semiconductor quantum dot-conjugated antibodies were successfully developed to label Cryptosporidium parvum and Giardia lamblia. This novel fluorescence system exhibited superior photostability, gave 1.5- to 9-fold-higher signal-to-noise ratios than traditional organic dyes in detecting C. parvum, and allowed dual-color detection for C. parvum and G. lamblia.

Zhu, Liang; Ang, Simon; Liu, Wen-tso

2004-01-01

133

Crystal Structures of Carbamate Kinase from Giardia lamblia Bound with Citric Acid and AMP-PNP  

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The parasite Giardia lamblia utilizes the L-arginine dihydrolase pathway to generate ATP from L-arginine. Carbamate kinase (CK) catalyzes the last step in this pathway, converting ADP and carbamoyl phosphate to ATP and ammonium carbamate. Because the L-arginine pathway is essential for G. lamblia survival and absent in high eukaryotes including humans, the enzyme is a potential target for drug development. We have determined two crystal structures of G. lamblia CK (glCK) with bound ligands. O...

Lim, Kap; Kulakova, Liudmila; Galkin, Andrey; Herzberg, Osnat

2013-01-01

134

Serum antibodies to Giardia lamblia by age in populations in Colorado and Thailand.  

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We measured levels of antibodies to Giardia lamblia by age in serum specimens from persons in Denver, Colorado, and Soongnern, Thailand. Serum levels of immunoglobulin (Ig) G, IgM, and IgA G lamblia-specific antibodies measured by enzyme-linked immunosorbent assay increased substantially during childhood in both geographic areas, although children in Soongnern showed significantly higher mean levels of each antibody class (P less than .05). After adolescence, levels of G lamblia-specific IgM ...

Janoff, E. N.; Taylor, D. N.; Echeverria, P.; Glode, M. P.; Blaser, M. J.

1990-01-01

135

Effect of Giardia lamblia Infection on the Cognitive Function of School children  

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Background: The association between helminthic parasitic infection and cognitive function has long been recognized, however there are few reports about Giardia lamblia infection. This paper describes a study about the effect of G. lamblia infection on the cognitive function. Methods: One hundred thirty two children infected with G. lamblia from Robat Karim south of western Tehran, Iran were compared with 150 children without any parasitic infection. These two groups were identical in socioeco...

Partovi, F.; Khalili, G.; Kariminia, A.; Mahmoudzadeh- Niknam, H.

2007-01-01

136

Performance of Three Enzyme Immunoassays and Two Direct Fluorescence Assays for Detection of Giardia lamblia in Stool Specimens Preserved in ECOFIX  

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ECOFIX is a single-vial stool preservative that is both formalin- and mercury-free. We evaluated the abilities of three commercial Giardia lamblia-specific enzyme immunoassays (EIAs) (ProSpecT Giardia Microplate Assay [Alexon-Trend Inc.], Giardia Test [Techlab], and Premier Giardia lamblia [Meridian Diagnostics, Inc.]) and two commercial direct fluorescent-antibody (FA) assays for G. lamblia (Crypto/Giardia IF Test [Techlab] and Merifluor Cryptosporidium/Giardia [Meridian Diagnostics, Inc.]) ...

Fedorko, Daniel P.; Williams, Esther C.; Nelson, Nancy A.; Calhoun, Leslie B.; Yan, Sizhuang S.

2000-01-01

137

GiardiaDB and TrichDB: integrated genomic resources for the eukaryotic protist pathogens Giardia lamblia and Trichomonas vaginalis  

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GiardiaDB (http://GiardiaDB.org) and TrichDB (http://TrichDB.org) house the genome databases for Giardia lamblia and Trichomonas vaginalis, respectively, and represent the latest additions to the EuPathDB (http://EuPathDB.org) family of functional genomic databases. GiardiaDB and TrichDB employ the same framework as other EuPathDB sites (CryptoDB, PlasmoDB and ToxoDB), supporting fully integrated and searchable databases. Genomic-scale data available via these resources may be queried based o...

Aurrecoechea, Cristina; Brestelli, John; Brunk, Brian P.; Carlton, Jane M.; Dommer, Jennifer; Fischer, Steve; Gajria, Bindu; Gao, Xin; Gingle, Alan; Grant, Greg; Harb, Omar S.; Heiges, Mark; Innamorato, Frank; Iodice, John; Kissinger, Jessica C.

2009-01-01

138

Development of functional gastrointestinal disorders after Giardia lamblia infection  

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Abstract Background Functional gastrointestinal disorders (FGID) may occur following acute gastroenteritis. This long-term complication has previously not been described after infection with the non-invasive protozoan Giardia lamblia. This study aims to characterize persistent abdominal symptoms elicited by Giardia infection according to Rome II criteria and symptoms scores. Methods Structured interview and questionnaires 12–30 months after t...

Hanevik Kurt; Dizdar Vernesa; Langeland Nina; Hausken Trygve

2009-01-01

139

Mechanisms of Giardia lamblia differentiation into cysts.  

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Microbiologists have long been intrigued by the ability of parasitic organisms to adapt to changes in the environment. Since most parasites occupy several niches during their journey between vectors and hosts, they have developed adaptive responses which allow them to survive under adverse conditions. Therefore, the life cycles of protozoan and helminthic parasites are excellent models with which to study numerous mechanisms involved in cell differentiation, such as the regulation of gene exp...

Luja?n, H. D.; Mowatt, M. R.; Nash, T. E.

1997-01-01

140

snoRNA, a Novel Precursor of microRNA in Giardia lamblia  

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An Argonaute homolog and a functional Dicer have been identified in the ancient eukaryote Giardia lamblia, which apparently lacks the ability to perform RNA interference (RNAi). The Giardia Argonaute plays an essential role in growth and is capable of binding specifically to the m7G-cap, suggesting a potential involvement in microRNA (miRNA)-mediated translational repression. To test such a possibility, small RNAs were isolated from Giardia trophozoites, cloned, and sequenced. A 26-nucleotide...

2008-01-01

 
 
 
 
141

Some hematimetric findings in human Giardia lambia infection Valores hematimétricos na infecção humana causada por Giardia lamblia  

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Up to now few reports about haematological alterations induced by Giardia lamblia infection have been described. Because there are questions on this matter still not answered, we carried out a study to evaluate some erythrometric and leucometric parameters in a sample that consisted of 55 patients exclusively infected with G. lamblia and of 55 sex and age matched parasite-free individuals. The haematological parameters evaluated were: mean corpuscular volume (MCV), hemoglobin concentration, a...

1996-01-01

142

Bax function in the absence of mitochondria in the primitive protozoan Giardia lamblia.  

Science.gov (United States)

Bax-induced permeabilization of the mitochondrial outer membrane and release of cytochrome c are key events in apoptosis. Although Bax can compromise mitochondria in primitive unicellular organisms that lack a classical apoptotic machinery, it is still unclear if Bax alone is sufficient for this, or whether additional mitochondrial components are required. The protozoan parasite Giardia lamblia is one of the earliest branching eukaryotes and harbors highly degenerated mitochondrial remnant organelles (mitosomes) that lack a genome. Here we tested whether human Bax expressed in Giardia can be used to ablate mitosomes. We demonstrate that these organelles are neither targeted, nor compromised, by Bax. However, specialized compartments of the regulated secretory pathway are completely ablated by Bax. As a consequence, maturing cyst wall proteins that are sorted into these organelles are released into the cytoplasm, causing a developmental arrest and cell death. Interestingly, this ectopic cargo release is dependent on the carboxy-terminal 22 amino acids of Bax, and can be prevented by the Bax-inhibiting peptide Ku70. A C-terminally truncated Bax variant still localizes to secretory organelles, but is unable to permeabilize these membranes, uncoupling membrane targeting and cargo release. Even though mitosomes are too diverged to be recognized by Bax, off-target membrane permeabilization appears to be conserved and leads to cell death completely independently of mitochondria. PMID:17534438

Hehl, Adrian B; Regos, Attila; Schraner, Elisabeth; Schneider, André

2007-01-01

143

PURIFICATION OF 'GIARDIA MURIS' CYSTS BY A VELOCITY SEDIMENTATION  

Science.gov (United States)

Giardia muris cysts were separated from fecal contaminants in primary isolates using unit gravity velocity sedimentation. Crude isolates were overlayed onto a Percoll density gradient, 1.01 g/cu cm to 1.03 g/cu cm. Giardia muris cysts were well separated from faster-sedimenting f...

144

Kinetics of lymphocyte subpopulation in intestinal mucosa of protein deficient Giardia lamblia infected mice.  

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Kinetics of gut lymphocyte subpopulations were studied in normal and malnourished groups of mice infected with Giardia lamblia. The maximum parasite load was observed at second, third, and first week of postinfection in normal controls, moderate (8%) and severe (3%) protein deficient groups respectively. The number of G lamblia trophozoite in 3% protein deficient group was low compared with control groups. A significant increase in T cell population of intraepithelial lymphocytes and lamina p...

Upadhyay, P.; Ganguly, N. K.; Walia, B. N.; Mahajan, R. C.

1986-01-01

145

Impaired Parasite Attachment as Fitness Cost of Metronidazole Resistance in Giardia lamblia?  

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Infections with the diarrheagenic protozoan pathogen Giardia lamblia are most commonly treated with metronidazole (Mz). Treatment failures with Mz occur in 10 to 20% of cases and Mz resistance develops in the laboratory, yet clinically, Mz-resistant (Mzr) G. lamblia has rarely been isolated from patients. To understand why clinical Mzr isolates are rare, we questioned whether Mz resistance entails fitness costs to the parasite. Our studies employed several newly generated and established isog...

Tejman-yarden, Noa; Millman, Maya; Lauwaet, Tineke; Davids, Barbara J.; Gillin, Frances D.; Dunn, Linda; Upcroft, Jacqueline A.; Miyamoto, Yukiko; Eckmann, Lars

2011-01-01

146

Transcriptional Analysis of Three Major Putative Phosphatidylinositol Kinase Genes in a Parasitic Protozoan, Giardia lamblia  

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The current investigation evaluates the expression of phosphatidylinositol kinase (PIK) genes in the parasitic protozoan, Giardia lamblia. The G. lamblia Genome Database revealed the presence of two putative phosphatidylinositol-3-kinase (gPI3K) and one phosphatidylinositol-4-kinase (gPI4K) genes resembling the catalytic subunit of eukaryotic PIKs. Primers, designed to amplify mRNA of these three genes, were used to measure transcription by quantitative reverse-transcriptase polymerase chain ...

Hernandez, Yunuen; Zamora, Gus; Ray, Suparna; Chapoy, Jaime; Chavez, Edna; Valvarde, Robert; Williams, Ebonye; Aley, Stephen B.; Das, Siddhartha

2007-01-01

147

Spontaneous chromosome rearrangements in the protozoan Giardia lamblia: estimation of mutation rates.  

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Subcloned lines of the WB strain of Giardia lamblia contain polymorphic ribosomal RNA (rRNA) encoding chromosomes (Le Blancq et al., Nucl. Acids Res. 1991, 19, 4405-4412). We show that in a continuously propagated culture of G.lamblia trophozoites the proportion of trophozoites with rearranged rRNA encoding chromosomes gradually increases, consistent with the high mutation rate of about 1% per cell per division cycle. This conclusion is based on the finding in one experiment that after about ...

1992-01-01

148

Tumor Necrosis Factor ? Contributes to Protection Against Giardia lamblia Infection in Mice  

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Giardia lamblia is a ubiquitous parasite that causes diarrhea. Effective control of Giardia infections in mice has been shown to involve IgA, T cells, mast cells, and IL-6. We now show that TNF? also plays an important role in the early control of giardiasis. Mice treated with neutralizing anti-TNF? antibodies or genetically deficient in TNF? were infected with the G. lamblia clone GS/(M)-H7. In both cases, mice lacking TNF? had much higher parasite numbers than controls during the first ...

Zhou, Ping; Li, Erqiu; Shea-donohue, Terez; Singer, Steven M.

2007-01-01

149

The Cre/loxP system in Giardia lamblia: genetic manipulations in a binucleate tetraploid protozoan.  

Science.gov (United States)

The bacteriophage-derived Cre/loxP system is a valuable tool that has revolutionised genetic and cell biological research in many organisms. We implemented this system in the intestinal parasite Giardia lamblia, an evolutionarily diverged protozoan whose binucleate and tetraploid genome organisation severely limits the application of reverse genetic approaches. We show that Cre-recombinase is functionally expressed in G. lamblia and demonstrate "recycling" of selectable markers. Providing the means for more complex and versatile genetic modifications, this technique massively increases the scope of functional investigations in G. lamblia and other protozoa with similar limitations with respect to genetic manipulation. PMID:24747534

Wampfler, Petra B; Faso, Carmen; Hehl, Adrian B

2014-07-01

150

Chromosome sequence maps of the Giardia lamblia assemblage A isolate WB.  

Science.gov (United States)

Two genotypes, assemblages A and B, of the pathogenic gut protozoan parasite Giardia lamblia infect humans. Symptoms of infection range from asymptomatic to chronic diarrhea. Giardia chromosomes have long been characterized but not until the publication of the first Giardia genome sequence was chromosome mapping work, commenced nearly two decades ago, completed. Initial mapping studies identified and ordered Not I chromosome segments (summating to 1.8 Mb) of the estimated 2 Mb chromosome 3. The resulting map was confirmed with the release of the Giardia genome sequence and this revitalized mapping. The result is that 93% of the WB isolate genome sequence has now been assigned to one of five major chromosomes, and community access to these data has been made available through GiardiaDB, the database for Giardia genomes. PMID:20739222

Upcroft, Jacqui A; Krauer, Kenia G; Upcroft, Peter

2010-10-01

151

Glucosylceramide synthesis inhibition affects cell cycle progression, membrane trafficking, and stage differentiation in Giardia lamblia[S  

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Synthesis of glucosylceramide via glucosylceramide synthase (GCS) is a crucial event in higher eukaryotes, both for the production of complex glycosphingolipids and for regulating cellular levels of ceramide, a potent antiproliferative second messenger. In this study, we explored the dependence of the early branching eukaryote Giardia lamblia on GCS activity. Biochemical analyses revealed that the parasite has a GCS located in endoplasmic reticulum (ER) membranes that is active in proliferati...

S?tefanic?, Sas?a; Spycher, Cornelia; Morf, Laura; Fabria?s, Gemma; Casas, Josefina; Schraner, Elisabeth; Wild, Peter; Hehl, Adrian B.; Sonda, Sabrina

2010-01-01

152

Adherence of Giardia lamblia trophozoites to Int-407 human intestinal cells  

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Attachment of Giardia lamblia trophozoites to enterocytes is essential for colonization of the small intestine and is considered a prerequisite for parasite-induced enterocyte dysfunction and clinical disease. In this work, coincubation of Giardia with Int-407 cells, was used as an in vitro model to study the role of cytoskeleton and surface lectins involved in the attachment of the parasite. This interaction was also studied by scanning and transmission electron microscopy. Adherence was dep...

Sousa, M. Ce?u; Gonc?alves, C. A.; Bairos, V. A.; Poiares-da-silva, J.

2001-01-01

153

High-Throughput Giardia lamblia Viability Assay Using Bioluminescent ATP Content Measurements?  

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The human pathogen Giardia lamblia is an anaerobic protozoan parasite that causes giardiasis, one of the most common diarrheal diseases worldwide. Although several drugs are available for the treatment of giardiasis, drug resistance has been reported and is likely to increase, and recurrent infections are common. The search for new drugs that can overcome the drug-resistant strains of Giardia is an unmet medical need. New drug screen methods can facilitate the drug discovery process and aid w...

Chen, Catherine Z.; Kulakova, Liudmila; Southall, Noel; Marugan, Juan J.; Galkin, Andrey; Austin, Christopher P.; Herzberg, Osnat; Zheng, Wei

2011-01-01

154

Amplification, expression, and packaging of a foreign gene by giardiavirus in Giardia lamblia.  

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Giardia lamblia is an intestinal protozoan parasite and one of the earliest eukaryotic divergents. The trophozoite multiplies via asexual binary fission and lacks all natural means of lateral gene transfer. A system is developed here for long-term expression of a foreign gene in this organism by exploiting recombinant virions derived from the giardiavirus (GLV), a double-stranded RNA virus that infects many Giardia isolates. An in vitro transcript of the cloned GLV cDNA, comprising the firefl...

Yu, D. C.; Wang, A. L.; Wang, C. C.

1996-01-01

155

High-speed microscopic imaging of flagella motility and swimming in Giardia lamblia trophozoites  

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We report, in this paper, several findings about the swimming and attachment mechanisms of Giardia lamblia trophozoites. These data were collected using a combination of a high-contrast CytoViva imaging system and a particle image velocimetry camera, which can capture images at speeds greater than 800 frames/s. Using this system, we discovered that, during rapid swimming of Giardia trophozoites, undulations of the caudal region contributed to forward propulsion combined with the beating of th...

Lenaghan, Scott C.; Davis, Corinne A.; Henson, William R.; Zhang, Zhili; Zhang, Mingjun

2011-01-01

156

A deeply divergent phosphoglucomutase (PGM) of Giardia lamblia has both PGM and phosphomannomutase activities  

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Giardia lamblia, which is an important parasitic cause of diarrhea, uses activated forms of glucose to make glycogen and activated forms of mannose to make glycophosphosphoinositol anchors. A necessary step for glucose activation is isomerization of glucose-6-phosphate to glucose-1-phosphate by a phosphoglucomutase (PGM). Similarly, a phosphomannomutase (PMM) converts mannose-6-phosphate to mannose-1-phosphate. While whole genome sequences of Giardia predict two PGM candidates, no PMM candida...

Mitra, Sanghamitra; Cui, Jike; Robbins, Phillips W.; Samuelson, John

2010-01-01

157

Effect of Giardia lamblia Infection on the Cognitive Function of School children  

Directory of Open Access Journals (Sweden)

Full Text Available Background: The association between helminthic parasitic infection and cognitive function has long been recognized, however there are few reports about Giardia lamblia infection. This paper describes a study about the effect of G. lamblia infection on the cognitive function. Methods: One hundred thirty two children infected with G. lamblia from Robat Karim south of western Tehran, Iran were compared with 150 children without any parasitic infection. These two groups were identical in socioeconomic and nutritional status. Cognitive function was assessed using, three tests from Wechsler Intelligence Scale for children and one subset of the Clinical Evolution of Language Function. Results: Comparison of two groups revealed that uninfected children improved significantly more than children who had G. lamblia infection in the tests of Fluency (P< 0.02 and Digit-span Forwards/ Backwards (P< 0.004. Conclusion: Regular stool examination is suggested in areas with low hygienic conditions, since G. lamblia infection might be present without any clinical manifestation.

F Partovi

2007-05-01

158

Can Giardia lamblia infection lower the risk of acute diarrhea among preschool children?  

Science.gov (United States)

There are inconsistent findings concerning the role of Giardia lamblia in pediatric diarrhea. A prospective cohort study of the incidence of acute diarrhea among Israeli Arab preschool children offered the opportunity to examine the association between G. lamblia infection (at baseline) and subsequent diarrhea. Following baseline screening by light microscopy for the presence of Giardia in their stools, a cohort was assembled of 142 children who were followed between October 2003 and August 2004 for the incidence of diarrhea. Surveillance was performed through maternal interviews. At baseline, 21 children tested Giardia-positive. During the prospective surveillance, acute diarrhea occurred less often among Giardia-positive children (9.5%) than among children who were not infected with Giardia (26.5%). G. lamblia infection was associated with lower risk of acute diarrhea; adjusted odds ratio of 0.18 (95% confidence interval 0.04-0.93) (p = 0.041). This prospective study provides additional evidence that Giardia may lower the risk of subsequent acute diarrhea among preschool children. PMID:24158113

Muhsen, Khitam; Cohen, Dani; Levine, Myron M

2014-04-01

159

The Antimicrobial Effect of Methanol Extracts of Eucalyptus, Satureia Hortensis and Heracleum Glabrescens on Giardia Cysts  

Directory of Open Access Journals (Sweden)

Full Text Available Background and objectives: Giardiasis is a parasitic infection of smallintestine, with a worldwide distribution and the prevalence of Giardia indifferent parts of the world varies between 1 to 25%. Plants have the vastrange of antimicrobial and antifungal activity that can be identified asalternative treatments for bacterial and parasitic pathogens, the same asGiardia. In this study, the methanol extracts of eucalyptus plants, Satureiahortensis and Heracleum glabrescens, on Giardia cysts were studied in vitro.Material and Methods: The cysts were isolated from the feces using amodified Bingham. After counting by Hemusytumetr, they were placed nearby 200 mg / ml, 100 mg / ml and 10 mg / ml of the extracts prepared byDMSO for 30 and 60 minutes. Then, the number of dead and live cysts wascounted under a microscope.Results: the fatality effect of the extracts in 60 minutes is higher than thoseof 30 minutes. The methanol extracts of Satureia hortensis, Eucalyptus andHeracleum glabrescens with the dilution of 200 mg/ml in 60 mins have thefatality effect of 84/3%, 63/3% and 44%, respectively. The highestfatality(84.3% on Giardia cysts is related to Satureia hortensis with thedilution of 200 mg/ml in 60 mins and the Lowest(27% is related toHeracleum glabrescens with the dilution of 10 mg/ml in 30-minute period.The significant relationship between the plant type and the fatality ofmethanol extracts is observed.Conclusion: the methanol extracts of Eucalyptus, Heracleum glabrescensand especially Satureia hortensis have anti-parasitic effects in the laboratoryconditions. Thus, they can be used in the future, instead of the chemicalantiparasitic drugs.Key words: Antibacterial Giardia lamblia cysts, Eucalyptus, Satureiahortensis, Heracleum glabrescens, Tonekabon

Safarnejad Tameshkel, F.

2012-01-01

160

Structural basis for inactivation of Giardia lamblia carbamate kinase by disulfiram.  

Science.gov (United States)

Carbamate kinase from Giardia lamblia is an essential enzyme for the survival of the organism. The enzyme catalyzes the final step in the arginine dihydrolase pathway converting ADP and carbamoyl phosphate to ATP and carbamate. We previously reported that disulfiram, a drug used to treat chronic alcoholism, inhibits G. lamblia CK and kills G. lamblia trophozoites in vitro at submicromolar IC50 values. Here, we examine the structural basis for G. lamblia CK inhibition of disulfiram and its analog, thiram, their activities against both metronidazole-susceptible and metronidazole-resistant G. lamblia isolates, and their efficacy in a mouse model of giardiasis. The crystal structure of G. lamblia CK soaked with disulfiram revealed that the compound thiocarbamoylated Cys-242, a residue located at the edge of the active site. The modified Cys-242 prevents a conformational transition of a loop adjacent to the ADP/ATP binding site, which is required for the stacking of Tyr-245 side chain against the adenine moiety, an interaction seen in the structure of G. lamblia CK in complex with AMP-PNP. Mass spectrometry coupled with trypsin digestion confirmed the selective covalent thiocarbamoylation of Cys-242 in solution. The Giardia viability studies in the metronidazole-resistant strain and the G. lamblia CK irreversible inactivation mechanism show that the thiuram compounds can circumvent the resistance mechanism that renders metronidazole ineffectiveness in drug resistance cases of giardiasis. Together, the studies suggest that G. lamblia CK is an attractive drug target for development of novel antigiardial therapies and that disulfiram, an FDA-approved drug, is a promising candidate for drug repurposing. PMID:24558036

Galkin, Andrey; Kulakova, Liudmila; Lim, Kap; Chen, Catherine Z; Zheng, Wei; Turko, Illarion V; Herzberg, Osnat

2014-04-11

 
 
 
 
161

LOW PRESSURE ULTRAVEIOLET STUDIES FOR INACTIVATION OF GIARDIA MURIS CYSTS  

Science.gov (United States)

Cysts of Giardia muris were inactivated using a low pressure ultravolet (UV) light source. Cyst viability was detemined by both in vitro excystation and animal infectivity. Cyst doeses were counted using a flow cytometer for the animal infectivity experiments. Using in vitro excy...

162

Sensitive Detection of Giardia Cysts by Polymerase Chain Reaction (PCR)  

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Giardia is one of the most common human parasites and causes a lengthly course of nonbacterial diarrhea. Disease outbreaks due to Giardia infection are often attributed to contaminated water supplies. A major problem associated with detection for this organism is the lack of sensitive and reliable methods. PCR has the potential to address many of the limitations.We have performed a PCR-based method for sensitive detection of Giardia cysts. Because the sensitivity of PCR is a function of the e...

Nikaeen, M.; Ar, Mesdaghinia; Jeddi Tehrani, M.; Rezaian, M.; Vaezi, F.

2003-01-01

163

CONTROL OF 'GIARDIA' CYSTS BY FILTRATION: THE LABORATORY'S ROLE  

Science.gov (United States)

USEPA has sponsored research on the ability of slow sand, diatomaceous earth, and dual or multi-media filters to remove turbidity causing particles, coliforms, and Giardia cysts. The high volume Giardia sampler used during disease outbreaks was not appropriate for this research. ...

164

Inducible nitric oxide synthase in duodenum of children with Giardia lamblia infection.  

Directory of Open Access Journals (Sweden)

Full Text Available The investigation were performed on children with Giardia lamblia infection, diagnosed on the basis of positive stool tests for Giardia antigen (Elisa or by microscopical detection of trophozoites in duodenal fluid. In duodenal biopsies morphological studies and immunohistochemical reaction for inducible nitric oxide synthase (iNOS were performed. The control group was made up of duodenal tissue of children with excluded giardiasis and inflammation of the upper part of gastrointestinal tract. The duodenal biopsies from children without Giardia lamblia infection were found to have a high immunoreactivity for iNOS in enterocytes, the cells of intestinal crypts, endothelial cells of vessels and connective tissue cells of lamina propria. In children with giardiasis: in some biopsies the expression of iNOS was as high as in control group, in others was weaker detectable and the shortening of intestinal villi was seen. There were also duodenal biopsies with the lack of immunoreactivity for iNOS, with shorter villi and a large amount of mucus in the intestinal epithelium. Beside of goblet cells, also enterocytes were loaded with mucus. The pathological changes may cause malabsorption and also may have a negative influence on the defense of the intestinal wall against Giardia lamblia infection. The different morphological and immunohistochemical results in the duodenum of children with giardiasis can elucidate a variety of clinical symptoms from asymptomatic to severe infection.

Agnieszka Kolasa

2010-08-01

165

Impacto de la dieta sobre la inducción de infección con quistes de Giardia lamblia en ratas Sprague-Dawley The effect of malnourishment on the development of giardiosis in Sprague-Dawley rats  

Directory of Open Access Journals (Sweden)

Full Text Available Objetivo. Evaluar el efecto de la desnutrición en la inducción de la giardiosis con diferentes concentraciones de quistes de Giardia lamblia utilizando como modelo animal ratas Sprague-Dawley. Material y métodos. Es un estudio experimental efectuado entre 1995 y 1999, en el Centro de Investigación en Alimentación y Desarrollo, de la ciudad de Hermosillo, estado de Sonora, México, y cuya muestra estuvo integrada por dos grupos de 6 a 8 unidades experimentales, las cuales recibieron dos tipos de dieta y cinco tratamientos con diferente concentración de inóculo de quistes de Giardia lamblia. Durante la fase experimental se monitoreó la excreción de quistes, ganancia de peso, consumo de alimento, análisis del contenido intestinal y daños macro y microscópicos en mucosa intestinal. El tratamiento estadístico de los datos consistió en análisis de varianza, y de residuales cuando fue necesario. Resultados. En los animales alimentados con una dieta que cubre sus requerimientos nutricionales (DN se observó que es posible provocar la infección con 60 quistes, mientras que en los animales desnutridos (dieta DLN la concentración que se requiere es de únicamente seis quistes para establecer daños a nivel de mucosa intestinal. Conclusiones. La ganancia de peso monitoreada durante los 10 días de ensayo no resultó ser un buen indicador de la infección por Giardia lamblia. El porcentaje de infección depende de la concentración de quistes inoculados y del estado de nutrición de los animales evaluados.Objective. To assess the effect of malnutrition on the development of giardiosis in Sprague-Dawley rats, using different inoculum sizes of Giardia lamblia cysts. Material and Methods. An experimental study was conducted between 1995 and 1999 at Centro de Investigación, Alimentación y Desarrollo (Center for Research, Food, and Development, in Hermosillo, Sonora, Mexico. The study population consisted of two groups of six to eight experimental units that were fed two different diets and inoculated five different concentrations of Giardia lamblia cysts. Data were collected on excretion of cysts, weight gain, food intake, bowel contents, and macro and microscopic lesions in the intestinal mucosa. Statistical analysis consisted of analysis of variance and residuals. Results. Animals fed with a diet meeting nutritional requirements required an infecting inoculum of 60 cysts, while malnourished rats required only six cysts to develop mucosal lesions. Conclusions. Weight gain monitored during ten days was not a good indicator of Giardia lamblia infection. Infection depended on cyst inoculum size as well as on the nutritional status of the tested animals.

Martha Elvia Díaz-Cinco

2002-07-01

166

In vitro inhibition of Giardia lamblia and Trichomonas vaginalis growth by bithionol, dichlorophene, and hexachlorophene.  

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Bithionol, dichlorophene, and hexachlorophene, which are used in treating some helminthic infections, killed trophozoites of Giardia lamblia and Trichomonas vaginalis in modified BI-S-33 and Asami media, respectively. Virtually all G. lamblia and T. vaginalis cells were killed within 24 h with a 0.42 mM concentration of these compounds, except that 0.93 mM dichlorophene was required for sterilizing T. vaginalis in the same period. In modified BI-S-33 and Asami media from which bovine and huma...

Takeuchi, T.; Kobayashi, S.; Tanabe, M.; Fujiwara, T.

1985-01-01

167

Isolate and epitope variability in susceptibility of Giardia lamblia to intestinal proteases.  

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The surface antigens of Giardia lamblia differ. To determine whether the unique surface antigens found in variants and isolates could differentially protect the parasite from digestion by intestinal protease, G. lamblia clones WB-2X (WB), GS/M-H7 (GS/M), and B6, each of which expresses a unique surface variant antigen, were exposed to alpha-chymotrypsin and trypsin at concentrations up to 20 mg/ml in culture medium. The number of surviving trophozoites and morphologic changes were assessed ov...

Nash, T. E.; Merritt, J. W.; Conrad, J. T.

1991-01-01

168

Cysteine-dependent zinc binding by membrane proteins of Giardia lamblia.  

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The abundant, highly variable surface proteins (VSPs) which cover the surface of Giardia lamblia trophozoites compose a group of extremely cysteine (C)-rich proteins in which more than half of the cysteines are in the motif CXXC. Because of the constancy of these features among the known VSPs and the prominence of cysteine and particularly CXXC in proteins that bind zinc and other metals, we asked whether G. lamblia VSPs bind zinc in vitro. VSPs are the major protein component of Triton X-114...

Zhang, Y. Y.; Aley, S. B.; Stanley, S. L.; Gillin, F. D.

1993-01-01

169

Acute trichinellosis increases susceptibility to Giardia lamblia infection in the mouse model.  

Science.gov (United States)

The intestinal protozoan parasite Giardia lamblia causes diarrhoea in humans and animals. In the present study, we used the C57BL/6 inbred mouse model to assess the impact of a nematode (Trichinella spiralis) infection on the course of a G. lamblia (clone GS/M-83-H7) infection. Acute trichinellosis coincided with transient intestinal inflammation and generated an intestinal environment that strongly promoted growth of G. lamblia trophozoites although the local anti-Giardia immunoglobulin (Ig) A production was not affected. This increased G. lamblia infection intensity correlated with intestinal mast cell infiltration, mast cell degranulation, and total IgE production. Furthermore, a G. lamblia single-infection investigated in parallel also resulted in intestinal mast cell accumulation but severe infiltration was triggered in the absence of IgE. Recently, intestinal mast cells emerging during a G. lamblia infection were reported to be involved in those immunological mechanisms that control intestinal proliferation of the parasite in mice. This anti-giardial activity was assumed to be related to the capacity of mast cells to produce IL-6. However, this previous assumption was questioned by our present immunohistological findings indicating that murine intestinal mast cells, activated during a G. lamblia infection were IL-6-negative. In the present co-infection experiments, mast cells induced during acute trichinellosis were not able to control a concurrent G. lamblia infection. This observation makes it feasible that the T. spiralis infection created an immunological and physiological environment that superimposed the anti-giardial effect of mast cells and thus favoured intestinal growth of G. lamblia trophozoites in double-infected mice. Furthermore, our findings raise the possibility that intestinal inflammation e.g. as a consequence of a 'pre-existing' nematode infection is a factor which contributes to increased susceptibility of a host to a G. lamblia infection. The phenomenon of a 'pre-existing' nematode infection prior to a G. lamblia infection is a frequent constellation in endemic areas of giardiasis and may therefore have a direct impact on the epidemiological situation of the disease. PMID:16677442

von Allmen, N; Christen, S; Forster, U; Gottstein, B; Welle, M; Müller, N

2006-08-01

170

Neuronal Nitric Oxide Synthase is Necessary for Elimination of Giardia lamblia Infections in Mice1  

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Nitric oxide (NO) produced by inducible nitric oxide synthase (NOS2) is important for control of numerous infections. In vitro, NO inhibits replication and differentiation of the intestinal protozoan parasite Giardia lamblia. However, the role of NO against this parasite has not been tested in vivo. IL-6 deficient mice fail to control Giardia infections and these mice have reduced levels of NOS2 mRNA in the small intestine following infection compared to wild-type mice. However, NOS2 gene-tar...

Li, Erqiu; Zhou, Ping; Singer, Steven M.

2006-01-01

171

Experimental Verification of the Identity of Variant-Specific Surface Proteins in Giardia lamblia Trophozoites  

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The cell membrane of a Giardia lamblia trophozoite is covered with a single species of variant-specific surface protein (VSP) that is replaced by another VSP every 6 to 13 generations of cell growth, possibly for an evasion of host immunity. Experimentally, only six VSP species have been verified to localize to the cell membrane thus far. By assuming that VSP contains multiple CXXC motifs, 219 vsp genes were annotated in GiardiaDB of the WB isolate. By further assuming that VSP possesses both...

Li, Wei; Saraiya, Ashesh A.; Wang, Ching C.

2013-01-01

172

Nitroimidazole drugs vary in their mode of action in the human parasite Giardia lamblia.  

Science.gov (United States)

Giardia lamblia (syn. duodenalis, intestinalis) is a globally occurring micro-aerophilic human parasite that causes gastrointestinal disease. Standard treatment of G. lamblia infections is based on the 5-nitroimidazole drugs metronidazole and tinidazole. In two other micro-aerophilic parasites, Entamoeba histolytica and Trichomonas vaginalis, 5-nitroimidazole drugs bind to proteins involved in the thioredoxin-mediated redox network and disrupt the redox equilibrium by inhibiting thioredoxin reductase and depleting intracellular thiol pools. The major aim of this study was to assess whether nitroimidazoles exert a similar toxic effect on G. lamblia physiology. The 5-nitroimidazoles metronidazole and tinidazole were found to bind to the same subset of proteins including thioredoxin reductase. However, in contrast to E. histolytica and T. vaginalis, none of the other proteins bound are candidates for being involved in the thioredoxin-mediated redox network. Translation elongation factor EF-1?, an essential factor in protein synthesis, was widely degraded upon treatment with 5-nitroimidazoles. 2-Nitroimidazole (azomycin) and the 5-nitroimidazole ronidazole did not bind to any G. lamblia proteins, which is in contrast to previous findings in E. histolytica and T. vaginalis. All nitroimidazoles tested reduced intracellular thiol pools in G. lamblia, but metronidazole, also in contrast to the situation in the other two parasites, had the slightest effect. Taken together, our results suggest that nitroimidazole drugs affect G. lamblia in a fundamentally different way than E. histolytica and T. vaginalis. PMID:24533278

Leitsch, David; Schlosser, Sarah; Burgess, Anita; Duchêne, Michael

2012-12-01

173

Arginine deiminase has multiple regulatory roles in the biology of Giardia lamblia.  

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The protozoan parasite Giardia lamblia uses arginine deiminase (ADI) to produce energy from free L-arginine under anaerobic conditions. In this work, we demonstrate that, in addition to its known role as a metabolic enzyme, it also functions as a peptidylarginine deiminase, converting protein-bound arginine into citrulline. G. lamblia ADI specifically binds to and citrullinates the arginine in the conserved CRGKA tail of variant-specific surface proteins (VSPs), affecting both antigenic switching and antibody-mediated cell death. During encystation, ADI translocates from the cytoplasm to the nuclei and appears to play a regulatory role in the expression of encystation-specific genes. ADI is also sumoylated, which might modulate its activity. Our findings reveal a dual role played by ADI and define novel regulatory pathways used by Giardia for survival. PMID:18697833

Touz, Maria Carolina; Rópolo, Andrea Silvana; Rivero, Maria Romina; Vranych, Cecilia Veronica; Conrad, John Thomas; Svard, Staffan Gunnar; Nash, Theodore Elliott

2008-09-01

174

Sensitive Detection of Giardia Cysts by Polymerase Chain Reaction (PCR  

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Full Text Available Giardia is one of the most common human parasites and causes a lengthly course of nonbacterial diarrhea. Disease outbreaks due to Giardia infection are often attributed to contaminated water supplies. A major problem associated with detection for this organism is the lack of sensitive and reliable methods. PCR has the potential to address many of the limitations.We have performed a PCR-based method for sensitive detection of Giardia cysts. Because the sensitivity of PCR is a function of the efficiency of DNA extraction from cysts, we have also compared some different methods for DNA extraction from the cysts. Giardia cysts were collected from infected human, partially purified and serially diluted samples were prepared. DNA was extracted by 3 different methods and we found that simple repeated freezing and thawing was the best method for extraction of DNA from the cysts. A 163 bp conserved fragment related to the giardial heat shock protein (HSP70 gene was used as the target for PCR amplification. We were able to detect as few as 5 cysts in the samples. The results suggest the potential utilities of PCR for sensitive detection of Giardia in water sources.

M Nikaeen

2003-07-01

175

Lysosomal protein trafficking in Giardia lamblia: common and distinct features  

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Giardia is a flagellated protozoan parasite that has to face different microenvironments during its life cycle in order to survive. All cells exchange materials with the extracellular medium through the reciprocal processes of endocytosis and secretion. Unlike more evolved cells, Giardia lacks a defined endosomal/lysosomal system, but instead possesses peripheral vacuoles that play roles in endocytosis, degradation, recycling, and secretion of proteins during growth and differentiation of the...

Touz, Maria C.; Rivero, Maria R.; Miras, Silvana L.; Bonifacino, Juan S.

2012-01-01

176

Ozonoterapia en el síndrome de malabsorción intestinal secundario a parasitismo por Giardia lamblia: estudio preliminar  

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Se estudió el efecto de la ozonoterapia combinada (OLEOZON® oral y ozonoterapia rectal) en el síndrome de malabsorción intestinal, secundario a parasitismo intestinal por Giardia lamblia. Se tomaron 186 pacientes y se formaron 3 grupos de 62 pacientes cada uno. El primer grupo se trató con metronidazol y vitaminoterapia, el segundo con OLEOZON® oral y vitaminoterapia y el tercero con ozonoterapia combinada y vitaminoterapia. Los pacientes fueron evaluados clínicamente por drenaje bilia...

2003-01-01

177

Tetracyclines as antiparasitic agents: lipophilic derivatives are highly active against Giardia lamblia in vitro.  

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Comparisons of the inhibitory activities of different tetracyclines have been reported for Plasmodium falciparum but no other parasites. The in vitro response of the intestinal parasite Giardia lamblia to six tetracyclines in current use was determined. In addition, the experimental drug thiacycline (EMD 33,330) was evaluated. Three groups were discerned, with representative 50 and 90% inhibitory concentrations of, respectively, 36 and 130 (tetracycline), 6.4 and 22 (doxycycline), and 1.8 and...

Edlind, T. D.

1989-01-01

178

ARGININE DEIMINASE PLAYS MULTIPLE REGULATORY ROLES IN THE BIOLOGY OF GIARDIA LAMBLIA  

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The protozoan parasite Giardia lamblia utilizes arginine deiminase (gADI) to produce energy from free L-arginine under anaerobic conditions. In this work, we demonstrate that in addition to its known role as a metabolic enzyme, it also functions as a pepidtyl-arginine deiminase converting protein-bound arginine into citrulline. gADI specifically binds to and citrullinates the arginine in the conserved CRGKA tail of variant-specific surface proteins (VSPs) affecting both antigenic switching an...

Touz, Maria Carolina; Ropolo, Andrea Silvana; Rivero, Maria Romina; Vranych, Cecilia Veronica; Conrad, John Thomas; Svard, Staffan Gunnar; Nash, Theodore Elliot

2008-01-01

179

Bax Function in the Absence of Mitochondria in the Primitive Protozoan Giardia lamblia  

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Bax-induced permeabilization of the mitochondrial outer membrane and release of cytochrome c are key events in apoptosis. Although Bax can compromise mitochondria in primitive unicellular organisms that lack a classical apoptotic machinery, it is still unclear if Bax alone is sufficient for this, or whether additional mitochondrial components are required. The protozoan parasite Giardia lamblia is one of the earliest branching eukaryotes and harbors highly degenerated mitochondrial remnant or...

Hehl, Adrian B.; Regos, Attila; Schraner, Elisabeth; Schneider, Andre?

2007-01-01

180

snoRNAs in Giardia lamblia: a novel role in RNA silencing?  

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In the expanding world of small regulatory RNAs, a recent paper by Saraiya and Wang has reported the identification in the protozoan parasite Giardia lamblia of a novel class of small RNAs, which are derived by Dicer processing of small nucleolar RNAs and have the potential to function as micro RNAs. Interestingly, these RNAs occur not only in this parasite but also in humans. PMID:19616476

Kolev, Nikolay G; Ullu, Elisabetta

2009-08-01

 
 
 
 
181

Bax function in the absence of mitochondria in the primitive protozoan Giardia lamblia  

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Bax-induced permeabilization of the mitochondrial outer membrane and release of cytochrome c are key events in apoptosis. Although Bax can compromise mitochondria in primitive unicellular organisms that lack a classical apoptotic machinery, it is still unclear if Bax alone is sufficient for this, or whether additional mitochondrial components are required. The protozoan parasite Giardia lamblia is one of the earliest branching eukaryotes and harbors highly degenerated mitochondrial remnant or...

Hehl, Adrian B.; Regos, Attila; Schraner, Elisabeth; Schneider, Andre?

2008-01-01

182

IDENTIFICATION OF GROWTH INHIBITING COMPOUNDS IN A GIARDIA LAMBLIA HIGH-THROUGHPUT SCREEN  

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Giardia lamblia is one of the most common eukaryotic pathogens and is classified by the CDC as a category B agent of bioterrorism. In a departure from more traditional research focused on specific pathways or molecules, we have developed a high-throughput assay for screening libraries of small compounds for inhibitors and enhancers of trophozoite multiplication. Following a 24-h period of culture in 384-well plates in the presence of compounds, trophozoites were fixed, stained and enumerated....

Santiago, Ruben Bonilla; Wu, Zijin; Zhang, Linghui; Widmer, Giovanni

2008-01-01

183

Detection and Genotyping of Entamoeba histolytica, Entamoeba dispar, Giardia lamblia, and Cryptosporidium parvum by Oligonucleotide Microarray  

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Entamoeba histolytica, Giardia lamblia, and Cryptosporidium parvum are the most frequently identified protozoan parasites causing waterborne disease outbreaks. The morbidity and mortality associated with these intestinal parasitic infections warrant the development of rapid and accurate detection and genotyping methods to aid public health efforts aimed at preventing and controlling outbreaks. In this study, we describe the development of an oligonucleotide microarray capable of detecting and...

Wang, Zheng; Vora, Gary J.; Stenger, David A.

2004-01-01

184

Proteomic analysis of the ventral disc of Giardia lamblia  

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Abstract Background Giardia lamblia is a multiflagellated protozoan that inhabits the small intestine of vertebrates, causing giardiasis. To colonize the small intestine, the trophozoites form of the parasite remains attached to intestinal epithelial cells by means of cytoskeletal elements that form a structure known as the ventral disc. Previous studies have shown that the ventral disc is made of tubulin and giardins. Results To obtain further informat...

Lourenço Daniela; Andrade Iamara; Terra Letícia; Guimarães Patricia; Zingali Russolina; de Souza Wanderley

2012-01-01

185

Susceptibility of Giardia lamblia to aminoglycoside protein synthesis inhibitors: correlation with rRNA structure.  

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The very limited development of antiparasitic agents targeting protein synthesis stems in part from the belief that parasite and host ribosomes are sufficiently similar to preclude selective toxicity. However, recent studies have revealed that Giardia lamblia rRNA has an unusual size and sequence; consequently, this organism and its homogeneous rRNA provide a useful model for the development of protein synthesis inhibitors with antiparasitic activity. In this study, I determined the sequence ...

Edlind, T. D.

1989-01-01

186

Modified PEHPS Medium as an Alternative for the In Vitro Culture of Giardia lamblia  

Science.gov (United States)

Commercial culture media present interlot variations in biological activity. We have previously designed a homemade and economic culture medium, PEHPS medium, for the axenic cultivation of Entamoeba histolytica and Trichomonas vaginalis. Trophozoites of amoebae and trichomonads grow well in this medium. Furthermore, the medium is stable for several months when stored frozen or refrigerated. The objective of this work was to modify PEHPS medium to support the in vitro growth of Giardia lamblia. Inocula of 5 × 103 trophozoites/mL of G. lamblia were incubated at 36.5°C in modified PEHPS or TYI-S-33 medium. Then, the growths of the three Giardia strains in both media were compared. The logarithmic growth phase lasted 72?h; the mean yield of the strains ranged from 10.06 to 11.43 × 105Giardia trophozoites/mL, and the range of duplication time in the three strains was from 5.67 to 6.06 in modified PEHPS medium. These growth characteristics were not significantly different from those obtained with TYI-S-33 medium. We conclude that modified PEHPS medium might be used for the axenic cultivation of G. lamblia.

Vargas-Villarreal, Javier; Mata-Cardenas, Benito D.; Hernandez-Garcia, Magda E.; Garza-Gonzalez, Jesus N.; De La Garza-Salinas, Laura H.; Gonzalez-Salazar, Francisco

2014-01-01

187

Modified PEHPS Medium as an Alternative for the In Vitro Culture of Giardia lamblia.  

Science.gov (United States)

Commercial culture media present interlot variations in biological activity. We have previously designed a homemade and economic culture medium, PEHPS medium, for the axenic cultivation of Entamoeba histolytica and Trichomonas vaginalis. Trophozoites of amoebae and trichomonads grow well in this medium. Furthermore, the medium is stable for several months when stored frozen or refrigerated. The objective of this work was to modify PEHPS medium to support the in vitro growth of Giardia lamblia. Inocula of 5 × 10(3) trophozoites/mL of G. lamblia were incubated at 36.5°C in modified PEHPS or TYI-S-33 medium. Then, the growths of the three Giardia strains in both media were compared. The logarithmic growth phase lasted 72?h; the mean yield of the strains ranged from 10.06 to 11.43 × 10(5) Giardia trophozoites/mL, and the range of duplication time in the three strains was from 5.67 to 6.06 in modified PEHPS medium. These growth characteristics were not significantly different from those obtained with TYI-S-33 medium. We conclude that modified PEHPS medium might be used for the axenic cultivation of G. lamblia. PMID:24982905

Vargas-Villarreal, Javier; Mata-Cárdenas, Benito D; Hernández-García, Magda E; Garza-González, Jesús N; De La Garza-Salinas, Laura H; González-Salazar, Francisco

2014-01-01

188

Identification of an immunogenic protein of Giardia lamblia using monoclonal antibodies generated from infected mice  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The humoral immune response plays an important role in the clearance of Giardia lamblia. However, our knowledge about the specific antigens of G. lamblia that induce a protective immune response is limited. The purpose of this study was to identify and [...] characterise the immunogenic proteins of G. lamblia in a mouse model. We generated monoclonal antibodies (moAbs) specific to G. lamblia (1B10, 2C9.D11, 3C10.E5, 3D10, 5G8.B5, 5F4, 4C7, 3C5 and 3C6) by fusing splenocytes derived from infected mice. Most of these moAbs recognised a band of ± 71 kDa (5G8 protein) and this protein was also recognised by serum from the infected mice. We found that the moAbs recognised conformational epitopes of the 5G8 protein and that this antigen is expressed on the cell surface and inside trophozoites. Additionally, antibodies specific to the 5G8 protein induced strong agglutination (> 70-90%) of trophozoites. We have thus identified a highly immunogenic antigen of G. lamblia that is recognised by the immune system of infected mice. In summary, this study describes the identification and partial characterisation of an immunogenic protein of G. lamblia. Additionally, we generated a panel of moAbs specific for this protein that will be useful for the biochemical and immunological characterisation of this immunologically interesting Giardia molecule.

Jael, Quintero; Diana Carolina, Figueroa; Rafael, Barcelo; Linda, Breci; Humberto, Astiazaran-Garcia; Lucila, Rascon; Ramon, Robles-Zepeda; Adriana, Garibay-Escobar; Enrique, Velazquez-Contreras; Gloria Leon, Avila; Jose Manuel, Hernandez-Hernandez; Carlos, Velazquez.

189

The transcriptional response to encystation stimuli in Giardia lamblia is restricted to a small set of genes.  

Science.gov (United States)

The protozoan parasite Giardia lamblia undergoes stage differentiation in the small intestine of the host to an environmentally resistant and infectious cyst. Encystation involves the secretion of an extracellular matrix comprised of cyst wall proteins (CWPs) and a ?(1-3)-GalNAc homopolymer. Upon the induction of encystation, genes coding for CWPs are switched on, and mRNAs coding for a Myb transcription factor and enzymes involved in cyst wall glycan synthesis are upregulated. Encystation in vitro is triggered by several protocols, which call for changes in bile concentrations or availability of lipids, and elevated pH. However, the conditions for induction are not standardized and we predicted significant protocol-specific side effects. This makes reliable identification of encystation factors difficult. Here, we exploited the possibility of inducing encystation with two different protocols, which we show to be equally effective, for a comparative mRNA profile analysis. The standard encystation protocol induced a bipartite transcriptional response with surprisingly minor involvement of stress genes. A comparative analysis revealed a core set of only 18 encystation genes and showed that a majority of genes was indeed upregulated as a side effect of inducing conditions. We also established a Myb binding sequence as a signature motif in encystation promoters, suggesting coordinated regulation of these factors. PMID:20693303

Morf, Laura; Spycher, Cornelia; Rehrauer, Hubert; Fournier, Catharine Aquino; Morrison, Hilary G; Hehl, Adrian B

2010-10-01

190

Comparación de métodos de lisis y extracción de ADN de trofozoítos de Giardia lamblia COMPARISON OF LYSIS METHODS AND DNA EXTRACTION OF GIARDIA LAMBLIA TROPHOZOITES  

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Full Text Available Se evaluó la eficiencia de procedimientos de lisis y tratamientos de extracción de ADN de trofozoítos de Giardia lamblia respecto a la eficiencia de ruptura, cantidad y pureza de ADN, además de los tiempos de procesamiento y costos. Se testearon cinco métodos de lisis (agua destilada y calor; agua destilada, calor y proteinasa K; buffer de lisis D; buffer de lisis E y un kit comercial y tres métodos de purificación de ADN (fenol:cloroformo: isoamílico; Chelex 100 y un kit comercial. Los datos obtenidos se analizaron estadísticamente. La combinación de buffer de lisis E y Chelex fue un método simple y económico, que produjo alto rendimiento de ADN con baja pureza. Ella técnica comercial fue un método simple, más costoso que produjo bajas cantidades de ADN con un nivel de pureza apropiado para estudios molecularesThe efficiency of lysis procedures and DNA purification treatments of Giardia lamblia trophozoites were evaluated regarding the breaking-up efficiency, quantity and pureness of DNA, processing time and costs. Five lysis methods (distilled water and heating; distilled water, heating and proteinase K; buffer D Lysis; buffer E lysis, and commercial kit, and three DNA purification methods (phenol:chloroform:isoamilic, Chelex 100 and commercial kit were tested. The obtained data were statistically analyzed. The buffer E lysis and Chelex combination was simple and economic method which produced high DNA performance with low pureness. Commercial kit was simple and expensive method which generated low yields of DNA with appropriate purity level for molecular analysis

NORA B MOLINA

2006-12-01

191

A unique mechanism of nuclear division in Giardia lamblia involves components of the ventral disk and the nuclear envelope  

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Full Text Available The fine structure of the binucleate, parasitic protist Giardia lamblia during interphase and divisional stages was studied by serial thin sectioning and three-dimensional reconstructions. The earlier sign of nuclear division is the development of a few peripheral areas of densely packed chromatin directly attached to the inner nuclear envelope. An intracytoplasmic sheet of ventral disk components grows from the cell periphery towards one of the nuclei, apparently constricting this nucleus, which becomes located at a ventral bulge. After the basal bodies become duplicated, a full nuclear division occurs in trophozoites, giving two pairs of parent-daughter nuclei. This full division occurs in a dorsal-ventral direction, with the resulting nuclear pairs located at the sides of the two sets of basal bodies. A new ventral disk is formed from the disk-derived sheets in the cell harboring the four nuclei. Cytokinesis is polymorphic, but at early stages is dorsal-to-dorsal. Encysting trophozoites show the development of Golgi cisternae stacks and dense, specific secretory granules. 3-D reconstructions show that cysts contain a single pair of incompletely strangled nuclei. The dividing Giardia lacks a typical, microtubular spindle either inside or outside the nuclei. The nuclear envelope seems to be the only structure involved in the final division of the parent-daughter nuclei.

Alberto J. Solari

2003-12-01

192

A unique mechanism of nuclear division in Giardia lamblia involves components of the ventral disk and the nuclear envelope  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english The fine structure of the binucleate, parasitic protist Giardia lamblia during interphase and divisional stages was studied by serial thin sectioning and three-dimensional reconstructions. The earlier sign of nuclear division is the development of a few peripheral areas of densely packed chromatin d [...] irectly attached to the inner nuclear envelope. An intracytoplasmic sheet of ventral disk components grows from the cell periphery towards one of the nuclei, apparently constricting this nucleus, which becomes located at a ventral bulge. After the basal bodies become duplicated, a full nuclear division occurs in trophozoites, giving two pairs of parent-daughter nuclei. This full division occurs in a dorsal-ventral direction, with the resulting nuclear pairs located at the sides of the two sets of basal bodies. A new ventral disk is formed from the disk-derived sheets in the cell harboring the four nuclei. Cytokinesis is polymorphic, but at early stages is dorsal-to-dorsal. Encysting trophozoites show the development of Golgi cisternae stacks and dense, specific secretory granules. 3-D reconstructions show that cysts contain a single pair of incompletely strangled nuclei. The dividing Giardia lacks a typical, microtubular spindle either inside or outside the nuclei. The nuclear envelope seems to be the only structure involved in the final division of the parent-daughter nuclei.

Solari, Alberto J.; Rahn, Monica I.; Saura, Alicia; Lujan, Hugo D..

193

??????: Giardia intestinalis  

Full Text Available Protozoa Giardiinae Giardia intestinalis Giardia duodenalis (synonym) NCBI 5741 Giardia intestin alis (scientific name) NCBI 5741 Giardia lamblia (genbank synonym) NCBI 5741

194

Structure of the prolyl-tRNA synthetase from the eukaryotic pathogen Giardia lamblia.  

Science.gov (United States)

The genome of the human intestinal parasite Giardia lamblia contains only a single aminoacyl-tRNA synthetase gene for each amino acid. The Giardia prolyl-tRNA synthetase gene product was originally misidentified as a dual-specificity Pro/Cys enzyme, in part owing to its unexpectedly high off-target activation of cysteine, but is now believed to be a normal representative of the class of archaeal/eukaryotic prolyl-tRNA synthetases. The 2.2 Å resolution crystal structure of the G. lamblia enzyme presented here is thus the first structure determination of a prolyl-tRNA synthetase from a eukaryote. The relative occupancies of substrate (proline) and product (prolyl-AMP) in the active site are consistent with half-of-the-sites reactivity, as is the observed biphasic thermal denaturation curve for the protein in the presence of proline and MgATP. However, no corresponding induced asymmetry is evident in the structure of the protein. No thermal stabilization is observed in the presence of cysteine and ATP. The implied low affinity for the off-target activation product cysteinyl-AMP suggests that translational fidelity in Giardia is aided by the rapid release of misactivated cysteine. PMID:22948920

Larson, Eric T; Kim, Jessica E; Napuli, Alberto J; Verlinde, Christophe L M J; Fan, Erkang; Zucker, Frank H; Van Voorhis, Wesley C; Buckner, Frederick S; Hol, Wim G J; Merritt, Ethan A

2012-09-01

195

Presencia de Giardia lamblia y Cryptosporidium spp. en aguas residuales depuradas reutilizadas para riego agrícola en la isla de Tenerife, España. Efectos del transporte a larga distancia sobre la calidad del agua reutilizada Giardia lamblia and Cryptosporidium spp. Presence in treated wastewater reutilised for irrigation in Tenerife island, Spain. Long-distance transport effects in the reutilised water quality  

Directory of Open Access Journals (Sweden)

Full Text Available El empleo de aguas residuales depuradas para riego agrícola es la alternativa de reutilización con más relevancia hoy día, siempre y cuando se desarrolle con garantías sanitarias y medioambientales.Giardia lamblia y Cryptosporidium spp. son dos protozoos patógenos entéricos de amplia distribución ambiental, frecuentes en hábitats acuáticos. La investigación y detección de estos parásitos en aguas ha adquirido importancia en los últimos años debido a que poseen formas de dispersión resistentes a los tratamientos habituales, aplicados tanto en procesos de potabilización como de depuración, y a que han sido clasificados como patógenos emergentes causantes de importantes brotes de transmisión hídrica.En este trabajo se estudia la presencia de quistes de Giardia lamblia y ooquistes de Cryptosporidium spp. en el agua residual depurada de la ciudad de Santa Cruz de Tenerife que es transportada hasta el sur de la isla de Tenerife para su reutilización en agricultura. Asimismo se investiga el efecto del transporte, el almacenamiento y el tratamiento avanzado sobre la concentración de quistes y ooquistes a través del sistema, y la existencia de relaciones con otros parámetros bacteriológicos y físico-químicos.Los resultados obtenidos ponen de manifiesto comportamientos variables de los contenidos en quistes y ooquistes frente a los tratamientos aplicados, y el efecto depurador que el transporte a larga distancia, parece tener sobre el agua residual depurada.No se han encontrado relaciones entre las concentraciones de quistes y ooquistes en el agua residual depurada y el contenido de los indicadores tradicionales de contaminación fecal.Treated wastewater use for irrigation is, nowadays, the more relevant reutilization alternative of wastewater, if it is developed with sanitary and environmental warranties.Giardia lamblia and Cryptosporidium spp. two wide distributed enteric pathogen protozoan, which are frequent in aquatic habitats. These protozoan investigation and detection have acquired importance in the last years due to their dispersion forms, which show resistance to the habitual treatments of potabilization and purification, and their classification as emerging pathogens which are the causative agents of important hydrical transmission outbreaks.In our work, Giardia lamblia cyst and Cryptosporidium spp. oocyst presence in Santa Cruz de Tenerife treated wastewater which is transported to the South of the island to be reutilised in agriculture. Furthermore, transport, storage and advanced treatment effects against cyst and oocyst concentration throughout the system and relation existence with other bacteriological and physical-chemical parameters, are also investigated.The obtained results demonstrate variable behaviours in cyst and oocyst concentration against applied treatments, and the depurative effect of the long-distance transport which seems to have in treated wastewater.There was not found any relation between cyst and oocyst concentration in treated wastewater and the traditional indicators of faecal contamination.

Escolástico Aguiar González

2002-06-01

196

Growth inhibition of the intestinal parasite Giardia lamblia by a dietary lectin is associated with arrest of the cell cycle.  

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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-glucosa...

Ortega-barria, E.; Ward, H. D.; Keusch, G. T.; Pereira, M. E.

1994-01-01

197

Simultaneous Detection of Entamoeba histolytica, Giardia lamblia, and Cryptosporidium parvum in Fecal Samples by Using Multiplex Real-Time PCR  

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Entamoeba histolytica, Giardia lamblia, and Cryptosporidium are three of the most important diarrhea-causing parasitic protozoa. For many years, microscopic examination of stool samples has been considered to be the “gold standard” for diagnosis of E. histolytica, G. lamblia, and C. parvum infections. Recently, more specific and sensitive alternative methods (PCR, enzyme-linked immunosorbent assay, and direct fluorescent-antibody assay) have been introduced for all three of these parasiti...

Verweij, Jaco J.; Blange?, Roy A.; Templeton, Kate; Schinkel, Janke; Brienen, Eric A. T.; Rooyen, Marianne A. A.; Lieshout, Lisette; Polderman, Anton M.

2004-01-01

198

Isolation of two Giardia lamblia (WB strain) clones with distinct surface protein and antigenic profiles and differing infectivity and virulence.  

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To determine the relationship between antigenic profiles and pathogenicity among Giardia lamblia clones (WB strain), trophozoites were cloned by the technique of limiting dilution. The phenotype of each clone was determined by an indirect immunofluorescence test using a polyclonal rabbit anti-G. lamblia trophozoite serum made against the parent strain. Two clones were chosen for further studies: a highly fluorescent clone, F+, in which more than 95% of the trophozoites fluoresced, and a low-f...

Udezulu, I. A.; Visvesvara, G. S.; Moss, D. M.; Leitch, G. J.

1992-01-01

199

COMPARISON OF 'GIARDIA MICROTI' AND 'SPIRONUCLEUS MURIS' CYSTS IN THE VOLE: AN IMMUNOCYTOCHEMICAL, LIGHT, AND ELECTRON MICROSCOPIC STUDY (JOURNAL VERSION)  

Science.gov (United States)

Cysts of the genus Spironucleus share many common morphological features with Giardia cysts including: 2-4 nuclei, flagellar axonemes, a distinct cyst wall, and they even display the same immunostaining as Giardia cysts when labeled with antibodies specific for Giardia cyst wall....

200

Simultaneous expression of different variant-specific surface proteins in single Giardia lamblia trophozoites during encystation.  

Science.gov (United States)

A novel variant-specific surface protein (VSP) from Giardia was identified using the monoclonal antibody 9B10, raised against purified cyst walls. VSP9B10B is preferentially induced during encystation and expressed simultaneously with other VSPs on the surface of encysting trophozoites. These results support the hypothesis that encystation and antigenic variation are processes that are mechanistically related. PMID:12183579

Carranza, Pedro G; Feltes, Gisela; Ropolo, Andrea; Quintana, Silvia M C; Touz, María C; Luján, Hugo D

2002-09-01

 
 
 
 
201

Simultaneous Expression of Different Variant-Specific Surface Proteins in Single Giardia lamblia Trophozoites during Encystation  

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A novel variant-specific surface protein (VSP) from Giardia was identified using the monoclonal antibody 9B10, raised against purified cyst walls. VSP9B10B is preferentially induced during encystation and expressed simultaneously with other VSPs on the surface of encysting trophozoites. These results support the hypothesis that encystation and antigenic variation are processes that are mechanistically related.

Carranza, Pedro G.; Feltes, Gisela; Ropolo, Andrea; Quintana, Silvia M. C.; Touz, Mari?a C.; Luja?n, Hugo D.

2002-01-01

202

Purification of Giardia muris cysts by velocity sedimentation.  

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Giardia muris cysts were separated from fecal contaminants in primary isolates by unit gravity velocity sedimentation. Crude isolates obtained by centrifugation over 1.0 M sucrose were overlaid onto a Percoll density gradient, 1.01 to 1.03 g/ml. G. muris cysts were well separated from faster-sedimenting fecal debris and slower-sedimenting Spironucleus muris and bacteria in 1.5 h.

Sauch, J. F.

1984-01-01

203

Calcium transport and catabolism of adenosine triphosphate in the protozoan parasite Giardia lamblia.  

Science.gov (United States)

1. Calcium uptake by washed trophozoites of Giardia lamblia was dependent on inorganic orthophosphate and stimulated by glucose. Uptake was both rapid and substantial: 224 +/- 73 nmoles Ca2+/mg protein/min. 2. Known inhibitors of Ca2+ uptake in mammalian cells also impeded Ca2+ influx into G. lamblia. 3. The inhibitor studies indicated that Ca2+ transport in G. lamblia was an active process. Energy for such a process could be provided by the action of ATPases. 4. Two types of ATPases were found in the parasite; one, a membrane-associated enzyme activated by Ca2+; the other, a soluble, cytosolic enzyme activated by Mg2+. 5. These enzymes differed not only in their intracellular distribution and divalent cation requirements, but also in their sensitivity to calmodulin antagonists. The particulate enzyme was sensitive to these inhibitors whereas the soluble ATPase was not. 6. Our data indicate that Ca2+ transport in G. lamblia is mediated by a membrane-bound, calmodulin-regulated, Ca2+-ATPase. PMID:2973967

Munoz, M L; Claggett, C E; Weinbach, E C

1988-01-01

204

Avaliação de diferentes métodos no diagnóstico laboratorial de Giardia lamblia  

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Giardia lamblia é um enteroparasita de prevalência significativa no mundo inteiro. Estudou-se a reprodutibilidade diagnóstica laboratorial por meio dos métodos Coprotest®, Direto modificado, Faust e Hematoxilina Férrica, para o protozoário G. lamblia, segundo a associação com algumas características da população de estudo tais como grupo etário, gênero e distribuição dos casos segundo a variação sazonal nos meses em que se desenvolveu a pesquisa. Fezes de 200 crianças da região de Araraquara-SP, foram examinadas pelos quatro métodos, e os resultados comparados. Verificou-se que 8% delas, encontravam-se parasitadas por G. lamblia. Não houve associação com o gênero; quanto à idade ocorreram mais casos no grupo de três a cinco anos e a maior freqüência de casos foi no mês de janeiro. Em relação ao diagnóstico laboratorial concluiu-se que os resultados mais confiáveis podem ser obtidos quando se utiliza duas metodologias associadas de ótima reprodutibilidade que neste estudo foram Coprotest - Faust; Direto-Faust e Coprotest-Direto (k > 0,81. Palavras-chave: G. lamblia; métodos diagnósticos; Coprotest®; Direto modificado; Faust; Hematoxilina Férrica.

J. G.D. GARCIA

2009-01-01

205

Giardia lamblia low-density lipoprotein receptor-related protein is involved in selective lipoprotein endocytosis and parasite replication  

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As Giardia lamblia is unable to synthesize cholesterol de novo, this steroid might be obtained from the host’s intestinal milieu by endocytosis of lipoproteins. In this work, we identified a putative Giardia lamblia low-density lipoprotein receptor-related proteins (GlLRP), a type-I membrane protein, which shares the substrate-N-terminal binding domain and a FXNPXY-type endocytic motif with human LRPs. Expression of tagged-GlLRP showed that it was localized predominantly in the endoplasmic ...

Rivero, Maria R.; Miras, Silvana L.; Quiroga, Rodrigo; Ro?polo, Andrea S.; Touz, Maria C.

2011-01-01

206

Trends of amino acid usage in the proteins from the unicellular parasite Giardia lamblia.  

Science.gov (United States)

Correspondence analysis of amino acid frequencies was applied to 75 complete coding sequences from the unicellular parasite Giardia lamblia, and it was found that three major factors influence the variability of amino acidic composition of proteins. The first trend strongly correlated with (a) the cysteine content and (b) the mean weight of the amino acids used in each protein. The second trend correlated with the global levels of hydropathy and aromaticity of each protein. Both axes might be related with the defense of the parasite to oxygen free radicals. Finally, the third trend correlated with the expressivity of each gene, indicating that in G. lamblia highly expressed sequences display a tendency to preferentially use a subset of the total amino acids. PMID:11162464

Garat, B; Musto, H

2000-12-29

207

Comparación de métodos de lisis y extracción de ADN de trofozoítos de Giardia lamblia / COMPARISON OF LYSIS METHODS AND DNA EXTRACTION OF GIARDIA LAMBLIA TROPHOZOITES  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Se evaluó la eficiencia de procedimientos de lisis y tratamientos de extracción de ADN de trofozoítos de Giardia lamblia respecto a la eficiencia de ruptura, cantidad y pureza de ADN, además de los tiempos de procesamiento y costos. Se testearon cinco métodos de lisis (agua destilada y calor; agua d [...] estilada, calor y proteinasa K; buffer de lisis D; buffer de lisis E y un kit comercial) y tres métodos de purificación de ADN (fenol:cloroformo: isoamílico; Chelex 100 y un kit comercial). Los datos obtenidos se analizaron estadísticamente. La combinación de buffer de lisis E y Chelex fue un método simple y económico, que produjo alto rendimiento de ADN con baja pureza. Ella técnica comercial fue un método simple, más costoso que produjo bajas cantidades de ADN con un nivel de pureza apropiado para estudios moleculares Abstract in english The efficiency of lysis procedures and DNA purification treatments of Giardia lamblia trophozoites were evaluated regarding the breaking-up efficiency, quantity and pureness of DNA, processing time and costs. Five lysis methods (distilled water and heating; distilled water, heating and proteinase K; [...] buffer D Lysis; buffer E lysis, and commercial kit), and three DNA purification methods (phenol:chloroform:isoamilic, Chelex 100 and commercial kit) were tested. The obtained data were statistically analyzed. The buffer E lysis and Chelex combination was simple and economic method which produced high DNA performance with low pureness. Commercial kit was simple and expensive method which generated low yields of DNA with appropriate purity level for molecular analysis

MOLINA, NORA B; POLVERINO, DANIELA; MINVIELLE, MARTA C; APEZTEGUÍA, MARÍA; AGUILAR, MARIO; BASUALDO, JUAN A.

208

Characterization of Microtubule-Binding and Dimerization Activity of Giardia lamblia End-Binding 1 Protein  

Science.gov (United States)

End-binding 1 (EB1) proteins are evolutionarily conserved components of microtubule (MT) plus-end tracking protein that regulate MT dynamics. Giardia lamblia, with two nuclei and cytoskeletal structures, requires accurate MT distribution for division. In this study, we show that a single EB1 homolog gene of G. lamblia regulates MT dynamics in mitosis. The haemagglutinin-tagged G. lamblia EB1 (GlEB1) localizes to the nuclear envelopes and median bodies, and is transiently present in mitotic spindles of dividing cells. Knockdown of GlEB1 expression using the morpholinos-based anti-EB1 oligonucleotides, resulted in a significant defect in mitosis of Giardia trophozoites. The MT-binding assays using recombinant GlEB1 (rGlEB1) proteins demonstrated that rGlEB1102–238, but not rGlEB11–184, maintains an MT-binding ability comparable with that of the full length protein, rGlEB11–238. Size exclusion chromatography showed that rGlEB1 is present as a dimer formed by its C-terminal domain and a disulfide bond. In vitro-mutagenesis of GlEB1 indicated that an intermolecular disulfide bond is made between cysteine #13 of the two monomers. Complementation assay using the BIM1 knockout mutant yeast, the yeast homolog of mammalian EB1, indicated that expression of the C13S mutant GlEB1 protein cannot rescue the mitotic defect of the BIM1 mutant yeast. These results suggest that dimerization of GlEB1 via the 13th cysteine residues plays a role during mitosis in Giardia.

Kim, Juri; Nagami, Sara; Lee, Kyu-Ho; Park, Soon-Jung

2014-01-01

209

Characterization of microtubule-binding and dimerization activity of Giardia lamblia end-binding 1 protein.  

Science.gov (United States)

End-binding 1 (EB1) proteins are evolutionarily conserved components of microtubule (MT) plus-end tracking protein that regulate MT dynamics. Giardia lamblia, with two nuclei and cytoskeletal structures, requires accurate MT distribution for division. In this study, we show that a single EB1 homolog gene of G. lamblia regulates MT dynamics in mitosis. The haemagglutinin-tagged G. lamblia EB1 (GlEB1) localizes to the nuclear envelopes and median bodies, and is transiently present in mitotic spindles of dividing cells. Knockdown of GlEB1 expression using the morpholinos-based anti-EB1 oligonucleotides, resulted in a significant defect in mitosis of Giardia trophozoites. The MT-binding assays using recombinant GlEB1 (rGlEB1) proteins demonstrated that rGlEB1102-238, but not rGlEB11-184, maintains an MT-binding ability comparable with that of the full length protein, rGlEB11-238. Size exclusion chromatography showed that rGlEB1 is present as a dimer formed by its C-terminal domain and a disulfide bond. In vitro-mutagenesis of GlEB1 indicated that an intermolecular disulfide bond is made between cysteine #13 of the two monomers. Complementation assay using the BIM1 knockout mutant yeast, the yeast homolog of mammalian EB1, indicated that expression of the C13S mutant GlEB1 protein cannot rescue the mitotic defect of the BIM1 mutant yeast. These results suggest that dimerization of GlEB1 via the 13th cysteine residues plays a role during mitosis in Giardia. PMID:24828878

Kim, Juri; Nagami, Sara; Lee, Kyu-Ho; Park, Soon-Jung

2014-01-01

210

A simple fibril and lectin model for cyst walls of Entamoeba and perhaps Giardia  

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Cyst walls of Entamoeba and Giardia protect them from environmental insults, stomach acids, and intestinal proteases. Each cyst wall contains a sugar homopolymer: chitin in Entamoeba and a unique N-acetylgalactosamine (GalNAc) homopolymer in Giardia. Entamoeba cyst wall proteins include Jacob lectins (carbohydrate-binding proteins) that cross-link chitin, chitinases that degrade chitin, and Jessie lectins that make walls impermeable. Giardia cyst wall proteins are also lectins that bind fibri...

Samuelson, John; Robbins, Phillips

2011-01-01

211

COMPARISON OF SOME FILTRATION PROCESSES APPROPRIATE FOR GIARDIA CYST REMOVAL  

Science.gov (United States)

Slow sand filtration, diatomaceous earth (DE) filtration, and coagulation-filtration (including conventional treatment, direct filtration, and in-line filtration), have been evaluated for Giardia cyst removal at pilot plant and/or field scale. Properly designed and operated, the ...

212

FACTORS PROMOTING 'IN VITRO' EXCYSTATION OF 'GIARDIA MURIS' CYSTS  

Science.gov (United States)

Giardia muris cysts, isolated from mouse feces, excysted routinely at levels greater than 90%, when induced in 1X Hanks' supplemented with 17 mM glutathione, 29 mM L-cysteine-HC1, and 50 mM NaHCO3 for 30 minutes at 35 deg. C, followed by washing and suspension in trypsin-Tyrode's...

213

Killing of Giardia lamblia by human milk is mediated by unsaturated fatty acids.  

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Giardia lamblia trophozoites were killed in vitro by 1% fresh human milk in the presence of bile. A similar effect was achieved in the absence of bile with milk which had been stored for at least 24 h at 6 degrees C. This killing activity was found to be caused by unsaturated fatty acids. Depending on their chain length and the number of double bonds, the concentrations of unsaturated fatty acids required for a 50% killing effect varied between 15 and 36 microM. The saturated palmitic and ste...

Rohrer, L.; Winterhalter, K. H.; Eckert, J.; Ko?hler, P.

1986-01-01

214

An unusually compact ribosomal DNA repeat in the protozoan Giardia lamblia.  

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The ribosomal RNA (rRNA) genes of the protozoan parasite Giardia lamblia have been analyzed with respect to size, composition and copy number. They are found to be remarkable in several respects. First, the rRNAs themselves are the smallest yet reported for any eukaryotic organism. Second, the genes encoding them are found as an exceptionally small tandemly repeated unit of only 5.4 kilobase-pairs. Third, the genes are extraordinarily G:C rich, even in regions which are highly conserved betwe...

Boothroyd, J. C.; Wang, A.; Campbell, D. A.; Wang, C. C.

1987-01-01

215

Tetracyclines as antiparasitic agents: lipophilic derivatives are highly active against Giardia lamblia in vitro.  

Science.gov (United States)

Comparisons of the inhibitory activities of different tetracyclines have been reported for Plasmodium falciparum but no other parasites. The in vitro response of the intestinal parasite Giardia lamblia to six tetracyclines in current use was determined. In addition, the experimental drug thiacycline (EMD 33,330) was evaluated. Three groups were discerned, with representative 50 and 90% inhibitory concentrations of, respectively, 36 and 130 (tetracycline), 6.4 and 22 (doxycycline), and 1.8 and 3.4 (thiacycline) micrograms/ml. These dramatic differences in activity correlate with increased lipophilicity. PMID:2619281

Edlind, T D

1989-12-01

216

[Research progress on the mechanisms of antigenic variation in Giardia lamblia].  

Science.gov (United States)

The intestinal protozoan parasite Giardia lamblia is one of the most common causes of diarrhoea and undergoes antigenic variation. In pathogenic microorganisms, antigenic variation is often described as a mechanism to evade the host immune system, resulting in chronic and/or recurrent infections. In the recent years, significant advances in the knowledge of the antigen switching process have been achieved. Here we review the principal knowledge on the mechanisms that regulate this process, including genomic organization, post-transcriptional gene silencing, expressional modifications, and processing and turnover of VSPs. PMID:23072166

Feng, Xian-Min; Wang, Yue-Hua; Ju, Xiao-Hong

2012-08-30

217

Isolation and expression of the gene for a major surface protein of Giardia lamblia.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To study the interactions between the parasitic protozoan Giardia lamblia and its environment, we have cloned the gene that encodes the two major surface-labeled trophozoite protein species. Sequence analysis of this gene reveals a single open reading frame specifying a hydrophilic, cysteine-rich (11.8%) protein of 72.5-kDa molecular mass with an amino-terminal signal peptide and a postulated hydrophobic membrane-spanning anchor region near the carboxyl terminus. Most of the cysteine residues...

Gillin, F. D.; Hagblom, P.; Harwood, J.; Aley, S. B.; Reiner, D. S.; Mccaffery, M.; So, M.; Guiney, D. G.

1990-01-01

218

Elevated levels of immunoglobulin A to Giardia lamblia during a waterborne outbreak of gastroenteritis.  

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During an outbreak of diarrheal illness among residents of a trailer park in rural Vermont, 37 (30%) of 122 residents met the case definition of outbreak-related giardiasis. Convalescent-phase sera from 24 residents and 20 nonresident control subjects were tested by enzyme-linked immunosorbent assay for immunoglobulin G (IgG), IgM, and IgA antibodies to Giardia lamblia. Residents showed higher levels of parasite-specific antibody than did nonresident controls for IgG and IgA but not IgM. Nine...

Birkhead, G.; Janoff, E. N.; Vogt, R. L.; Smith, P. D.

1989-01-01

219

A new-generation 5-nitroimidazole can induce highly metronidazole-resistant Giardia lamblia in vitro  

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The 5-nitroimidazole (NI) compound C17, with a side chain carrying a remote phenyl group in the 2-position of the imidazole ring, is at least 14-fold more active against the gut protozoan parasite Giardia lamblia than the 5-NI drug metronidazole (MTR), with a side chain in the 1-position of the imidazole ring, which is the primary drug for the treatment of giardiasis. Over 10 months, lines resistant to C17 were induced in vitro and were at least 12-fold more resistant to C17 than the parent s...

Dunn, Linda A.; Burgess, Anita G.; Krauer, Kenia G.; Eckmann, Lars; Vanelle, Patrice; Crozet, Maxime D.; Gillin, Frances D.; Upcroft, Peter; Upcroft, Jacqueline A.

2010-01-01

220

Lipidomic Analysis Reveals That Phosphatidylglycerol and Phosphatidylethanolamine are Newly Generated Phospholipids in an Early-Divergent Protozoan, Giardia lamblia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The pathogenic protozoan Giardia lamblia is known to not synthesize membrane lipids de novo. Therefore, it is possible that lipids in the small intestine, where trophozoites colonize, play key roles in regulating the growth and differentiation of this important pathogen. The focus of the current study is to conduct a complete lipidomic analysis and to test the hypothesis that Giardia has some ability to generate new phospholipids (PLs). Using mass spectrometry, now we show that phosphatidylgl...

Yichoy, Mayte; Nakayasu, Ernesto S.; Shpak, Max; Aguilar, Clemente; Aley, Stephen B.; Almeida, Igor C.; Das, Siddhartha

2009-01-01

 
 
 
 
221

Dual acylation accounts for the localization of {alpha}19-giardin in the ventral flagellum pair of Giardia lamblia  

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A Giardia-specific protein family denominated as alpha-giardins, represents the major protein component, besides tubulin, of the cytoskeleton of the human pathogenic parasite Giardia lamblia. One of its members, alpha19-giardin, carries an N-terminal sequence extension of MGCXXS, which in many proteins serves as a target for dual lipid conjugation: myristoylation at the glycine residue after removal of the methionine and palmitoylation at the cysteine residue. As the first experimental eviden...

Saric, M.; Vahrmann, A.; Niebur, D.; Kluempers, V.; Hehl, A. B.; Scholze, H.

2009-01-01

222

Dual Acylation Accounts for the Localization of ?19-Giardin in the Ventral Flagellum Pair of Giardia lamblia? †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A Giardia-specific protein family denominated as ?-giardins, represents the major protein component, besides tubulin, of the cytoskeleton of the human pathogenic parasite Giardia lamblia. One of its members, ?19-giardin, carries an N-terminal sequence extension of MGCXXS, which in many proteins serves as a target for dual lipid conjugation: myristoylation at the glycine residue after removal of the methionine and palmitoylation at the cysteine residue. As the first experimental evidence of ...

S?aric?, Mirela; Vahrmann, Anke; Niebur, Daniela; Kluempers, Verena; Hehl, Adrian B.; Scholze, Henning

2009-01-01

223

Clathrin-dependent pathways and the cytoskeleton network are involved in ceramide endocytosis by a parasitic protozoan, Giardia lamblia  

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Although identified as an early-diverged protozoan, Giardia lamblia shares many similarities with higher eukaryotic cells, including an internal membrane system and cytoskeleton, as well as secretory pathways. However, unlike many other eukaryotes, Giardia does not synthesize lipids de novo, but rather depends on exogenous sources for both energy production and organelle or membrane biogenesis. It is not known how lipid molecules are taken up by this parasite and if endocytic pathways are inv...

Hernandez, Yunuen; Castillo, Cynthia; Roychowdhury, Sukla; Hehl, Adrian; Aley, Stephen B.; Das, Siddhartha

2007-01-01

224

In vitro susceptibilities of 25 Giardia lamblia isolates of human origin to six commonly used antiprotozoal agents.  

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The role drug resistance plays in the occurrence of chronic and recurrent giardiasis has not been established. Extensive data on the susceptibility to antimicrobial agents of living Giardia spp. trophozoites from human origin are lacking. We have determined with a macrodilution method in semisolid medium the in vitro susceptibility of 25 Giardia lamblia isolates, all obtained by routine cultivation of the duodenal fluid of children to six commonly used antiprotozoal drugs. The results showed ...

Gordts, B.; Hemelhof, W.; Asselman, C.; Butzler, J. P.

1985-01-01

225

Cryopreservation of Giardia lamblia with dimethyl sulfoxide using a Dewar flask.  

Science.gov (United States)

This study examined the effect of varying freezing conditions on the human intestinal parasite Giardia lamblia (Portland-1 strain) using a constant vacuum in a Dewar flask and an ethanol bath to regulate the cooling rate. The cryopreservation of the trophozoite stage was investigated. Dimethyl sulfoxide (Me2SO), the cryoprotective agent of choice, was added directly to Giardia growth medium. Me2SO toxicity assays were conducted on those concentrations used in the freezing protocol. The results of this study indicated a 6.5% (v/v) Me2SO concentration yields a 90% survival based upon organism motility. A 30.9% cell viability was obtained by freezing in medium without a cryoprotective agent. Recommendations are offered concerning alternate viability criteria. PMID:6713946

Lyman, J R; Marchin, G L

1984-04-01

226

Neuronal nitric oxide synthase is necessary for elimination of Giardia lamblia infections in mice.  

Science.gov (United States)

NO produced by inducible NO synthase (NOS2) is important for the control of numerous infections. In vitro, NO inhibits replication and differentiation of the intestinal protozoan parasite Giardia lamblia. However, the role of NO against this parasite has not been tested in vivo. IL-6-deficient mice fail to control Giardia infections, and these mice have reduced levels of NOS2 mRNA in the small intestine after infection compared with wild-type mice. However, NOS2 gene-targeted mice and wild-type mice treated with the NOS2 inhibitor N-iminoethyl-L-lysine eliminated parasites as well as control mice. In contrast, neuronal NOS (NOS1)-deficient mice and wild-type mice treated with the nonspecific NOS inhibitor NG-nitro-L-arginine methyl ester and the NOS1-specific inhibitor 7-nitroindazole all had delayed parasite clearance. Finally, Giardia infection increased gastrointestinal motility in wild-type mice, but not in SCID mice. Furthermore, treatment of wild-type mice with NG-nitro-L-arginine methyl ester or loperamide prevented both the increased motility and the elimination of parasites. Together, these data show that NOS1, but not NOS2, is necessary for clearance of Giardia infection. They also suggest that increased gastrointestinal motility contributes to elimination of the parasite and may also contribute to parasite-induced diarrhea. Importantly, this is the first example of NOS1 being involved in the elimination of an infection. PMID:16365445

Li, Erqiu; Zhou, Ping; Singer, Steven M

2006-01-01

227

Comparação de quatro métodos laboratoriais para diagnóstico da Giardia lamblia em fezes de crianças residentes em Belém, Pará / Evaluation of four techniques for diagnosis of Giardia lamblia in children's stool from Belém city, Para State, Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Relatamos a comparação de quatro metodologias para o diagnóstico da Giardia lamblia em material fecal de crianças, Belém/PA. A Hematoxilina Férrica e o método direto apresentaram menor positividade, enquanto que o Método de Faust continua uma boa escolha para o diagnóstico e o Ensaio imunoenzimático [...] melhora a qualidade da detecção deste parasito. Abstract in english We report the evaluation of four techniques for Giardia lamblia diagnosis in children's stool. The Iron haematoxilin staining and direct examination with lugol showed lower positivity, while the method of Faust et al. Continues to be a good option for G. lamblia diagnosis and Immunoenzymatic assay i [...] ncreases the detection of this parasite.

Machado, Ricardo Luiz Dantas; Figueredo, Maria Cristina; Frade, Amanda Farage; Kudó, Mônica Eriko; Silva Filho, Manoel Gomes; Póvoa, Marinete Marins.

228

Identification in the Ancient Protist Giardia lamblia of Two Eukaryotic Translation Initiation Factor 4E Homologues with Distinctive Functions†  

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Eukaryotic translation initiation factor 4E (eIF4E) binds to the m7GTP of capped mRNAs and is an essential component of the translational machinery that recruits the 40S small ribosomal subunit. We describe here the identification and characterization of two eIF4E homologues in an ancient protist, Giardia lamblia. Using m7GTP-Sepharose affinity column chromatography, a specific binding protein was isolated and identified as Giardia eIF4E2. The other homologue, Giardia eIF4E1, bound only to th...

2005-01-01

229

Ozonoterapia en el síndrome de malabsorción intestinal secundario a parasitismo por Giardia lamblia: estudio preliminar  

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Full Text Available Se estudió el efecto de la ozonoterapia combinada (OLEOZON® oral y ozonoterapia rectal en el síndrome de malabsorción intestinal, secundario a parasitismo intestinal por Giardia lamblia. Se tomaron 186 pacientes y se formaron 3 grupos de 62 pacientes cada uno. El primer grupo se trató con metronidazol y vitaminoterapia, el segundo con OLEOZON® oral y vitaminoterapia y el tercero con ozonoterapia combinada y vitaminoterapia. Los pacientes fueron evaluados clínicamente por drenaje biliar y biopsia de yeyuno al inicio y final del tratamiento. Se alcanzó una mejoría importante en el tercer grupo (66,1 %, de los cuales, los diagnosticados tempranamente, 40,3 % obtuvo su curación. Se concluyó que la ozonoterapia combinada puede ser eficaz en esta patología.The effect of combined ozone therapy (oral OLEOZON® and rectal ozone therapy on the syndrome of intestinal malabsorption secondary to intestinal parasitism caused by Giardia lamblia was studied. 186 patients were selected and dividided into 3 groups of 62 patients each. The first group was treated with metronidazole and vitamin therapy, the second with oral OLEOZON® and vitamin therapy, and the third with combined ozone therapy and vitamin therapy. The patients were clinically evaluated by biliary drainage and jejunum biopsy at the beginning and at the end of the treatment. A significant improvement was observed in the third group (66.1 %. Of them, those that had been early diagnosed were cured (40.3 %. It was concluded that combined ozone therapy may be efficient in this pathology.

Nazarina Ivonne Méndez Pérez

2003-09-01

230

The structure of tryptophanyl-tRNA synthetase from Giardia lamblia reveals divergence from eukaryotic homologs.  

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The 2.1A crystal structure of tryptophanyl-tRNA synthetase (TrpRS) from the diplomonad Giardia lamblia reveals that the N-terminus of this class I aminoacyl-tRNA synthetase forms a 16-residue alpha-helix. This helix replaces a beta-hairpin that is required by human TrpRS for normal activity and has been inferred to play a similar role in all eukaryotic TrpRS. The primary sequences of TrpRS homologs from several basal eukaryotes including Giardia lack a set of three residues observed to stabilize interactions with this beta-hairpin in the human TrpRS. Thus the present structure suggests that the activation reaction mechanism of TrpRS from the basal eukaryote G. lamblia differs from that of higher eukaryotes. Furthermore, the protein as observed in the crystal forms an (alpha(2))(2) homotetramer. The canonical dimer interface observed in all previous structures of tryptophanyl-tRNA synthetases is maintained, but in addition each N-terminal alpha-helix reciprocally interlocks with the equivalent helix from a second dimer to form a dimer of dimers. Although we have no evidence for tetramer formation in vivo, modeling indicates that the crystallographically observed tetrameric structure would be compatible with the tRNA binding mode used by dimeric TrpRS and TyrRS. PMID:20438846

Arakaki, Tracy L; Carter, Megan; Napuli, Alberto J; Verlinde, Christophe L M J; Fan, Erkang; Zucker, Frank; Buckner, Frederick S; Van Voorhis, Wesley C; Hol, Wim G J; Merritt, Ethan A

2010-08-01

231

Characterisation of alpha-1 giardin: an immunodominant Giardia lamblia annexin with glycosaminoglycan-binding activity.  

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Alpha-1 giardin is an immunodominant protein in the intestinal protozoan parasite Giardia lamblia. The Triage((R)) parasite panel, used to detect copro-antigens in stool from giardiasis patients, reacts with an epitope between amino acids 160 and 200 in alpha-1 giardin. This region of the protein is also highly immunogenic during human infections. Alpha-1 giardin is related to annexins and like many other annexins it was shown to be plasma membrane associated. Immunoelectron and immunofluorescence microscopy revealed that some alpha-1 giardin are displayed on the surface of recently excysted cells. Recombinant alpha-1 giardin displayed a Ca(2+)-dependent binding to glycosaminoglycans (GAGs), in particular heparan sulphate, a common GAG in the intestinal tract. Recombinant alpha-1 giardin bound to thin sections of human small intestine, a binding which could be inhibited by adding increasing concentrations of sulphated sugars. A surface associated trypsin activated Giardia lectin (taglin) has been suggested to be important for G. lamblia attachment. In this study we show that a monoclonal antibody that inhibits taglin recognises alpha-1 and alpha-2 giardin. Thus, alpha-1 giardin is a highly immunoreactive GAG-binding protein, which may play a key role in the parasite-host interaction. Our results further show a conserved function of annexins from lower to higher eukaryotes. PMID:14527517

Weiland, Malin E-L; Palm, J E Daniel; Griffiths, William J; McCaffery, J Michael; Svärd, Staffan G

2003-10-01

232

Molecular Characterization of the Iranian Isolates of Giardia Lamblia: Application of the Glutamate Dehydrogenase Gene  

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Full Text Available Background: This study was conducted to determine of molecular epidemiology of the Giardia lamblia by PCR-RFLP method in Tehran, capital of Iran. Methods: Thirty eight stool samples were randomly selected from 125 patients diagnosed with giardiasis using microscopy in Tehran. DNA extraction of some samples were performed by phenol/chloroform/isoamyl alcohol method and to raise the sensitivity of the PCR assay, the genomic DNA of the others were extracted using glass beads and the QIAamp Stool Mini Kit in order to effectively remove the PCR inhibitors. A single step PCR-RFLP assay, targeting the glutamate dehydrogenase (gdh locus, was used to differentiate within and between assemblages A and B that have been found in humans. Results: Of the 38 isolates, 33 samples (87% were found as G. lamblia (genotype AII, 3 (7.8% belonged to assemblage B, genotype BIII, the mixed of genotype AII and B were detected only in two samples (5.2%. Conclusions: PCR-RFLP is a sensitive and powerful analytical tool that allows effective genotype discrimination within and between assemblages at targeting gdh gene, and makes it possible to identify the presence of mixed genotypes. Our data suggest that there is an anthroponotic origin of the infection route, assemblage A group II, in Tehran so it seems that the main reservoir of Giardia infection is humans in the area studies.

L Akhlaghi

2008-07-01

233

Comparação de quatro métodos laboratoriais para diagnóstico da Giardia lamblia em fezes de crianças residentes em Belém, Pará  

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Full Text Available Relatamos a comparação de quatro metodologias para o diagnóstico da Giardia lamblia em material fecal de crianças, Belém/PA. A Hematoxilina Férrica e o método direto apresentaram menor positividade, enquanto que o Método de Faust continua uma boa escolha para o diagnóstico e o Ensaio imunoenzimático melhora a qualidade da detecção deste parasito.

Machado Ricardo Luiz Dantas

2001-01-01

234

Molecular characterisation of a predominant antigenic region of Giardia lamblia variant surface protein H7.  

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During infection, the intestinal protozoan parasite Giardia lamblia undergoes continuous antigenic variation which is determined by diversification of the parasite's major surface antigen, named VSP (variant surface protein). One member from this protein family, VSP H7, is expressed by G. lamblia clone GS/M-83-H7. In the present study, we characterised a highly antigenic portion of VSP H7 which is positioned inside a 130 amino acid C-terminal region of the protein. This region overlaps with a cysteine-rich motif that is rather conserved within the VSP family. Detailed molecular dissection of the antigenic portion monitored a 12 amino acid peptidyl structure which constitutes a non-conformational epitope of VSP H7. In the murine host, this epitope is recognised relatively early (before day 10 p.i.) during infection and stimulates a strong intestinal immunoglobulin A response. At late infective stages (after day 10 p.i.) this immune reaction is progressively complemented by reactions against 'late' antigenic epitopes which are also located inside the 130 amino acid antigenic portion but in closer proximity to the C-terminal end of VSP H7 than the 12 amino acid epitope. Both the high antigenicity and the conserved character suggest that the 12 amino acid epitope is a key factor within the immunological interplay between G. lamblia and the experimental murine host. PMID:11403775

Bienz, M; Wittwer, P; Zimmermann, V; Müller, N

2001-06-01

235

Identification and characterization of gamma-giardin and the gamma-giardin gene from Giardia lamblia.  

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The giardins are abundant cytoskeletal proteins that range in size from 29-38 kDa and are specific to the ventral disk of the intestinal protozoan parasite Giardia lamblia. The 29-kDa (beta and beta-1; refs. 8-10) and the 33-kDa (alpha-1 and alpha-2; refs. 3 and 7) giardins have been characterized previously. In this paper we extend the analysis of the giardins to include the 38-kDa giardin, which we have named gamma-giardin. After purifying gamma-giardin by two-dimensional electrophoresis, we raised polyclonal antibodies to the protein and used them to demonstrate that gamma-giardin shares at least one epitope with 9 other giardin polypeptides and that it localizes to the ventral disk of the parasite. We also determined an internal peptide sequence of 12 amino acid residues and used this information to construct oligonucleotide probes for the gamma-giardin gene. After cloning the gene, we determined the nucleotide sequence of its 933-bp open reading frame and 866 bp of 5' and 3' flanking sequence. We found the downstream AGTPuAAPy motif typical of all G. lamblia genes sequenced to date, and determined that the single copy of the gamma-giardin gene localizes to the same chromosome or chromosomal cluster as the alpha-giardins. Finally, we demonstrated by primer extension analysis that gamma-giardin transcripts contain a short untranslated leader characteristic of G. lamblia messenger RNAs. PMID:1474999

Nohria, A; Alonso, R A; Peattie, D A

1992-11-01

236

Crystal structures of carbamate kinase from Giardia lamblia bound with citric acid and AMP-PNP.  

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The parasite Giardia lamblia utilizes the L-arginine dihydrolase pathway to generate ATP from L-arginine. Carbamate kinase (CK) catalyzes the last step in this pathway, converting ADP and carbamoyl phosphate to ATP and ammonium carbamate. Because the L-arginine pathway is essential for G. lamblia survival and absent in high eukaryotes including humans, the enzyme is a potential target for drug development. We have determined two crystal structures of G. lamblia CK (glCK) with bound ligands. One structure, in complex with a nonhydrolyzable ATP analog, adenosine 5'-adenylyl-?,?-imidodiphosphate (AMP-PNP), was determined at 2.6 Å resolution. The second structure, in complex with citric acid bound in the postulated carbamoyl phosphate binding site, was determined in two slightly different states at 2.1 and 2.4 Å resolution. These structures reveal conformational flexibility of an auxiliary domain (amino acid residues 123-170), which exhibits open or closed conformations or structural disorder, depending on the bound ligand. The structures also reveal a smaller conformational change in a region associated the AMP-PNP adenine binding site. The protein residues involved in binding, together with a model of the transition state, suggest that catalysis follows an in-line, predominantly dissociative, phosphotransfer reaction mechanism, and that closure of the flexible auxiliary domain is required to protect the transition state from bulk solvent. PMID:23700444

Lim, Kap; Kulakova, Liudmila; Galkin, Andrey; Herzberg, Osnat

2013-01-01

237

The effects of dihydroartemisinin on Giardia lamblia morphology and cell cycle in vitro.  

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Several anti-Giardia drugs, such as metronidazole, tinidazole, mebendazole, albendazole and furazolidone, are usually effective but have severe side effects and potential toxicity. An urgent need exists for more effective and less toxic agents that can act against this protozoan. For this purpose, the effects of dihydroartemisinin (DHA) on Giardia lamblia were investigated in vitro. Axenically grown G. lamblia trophozoites were treated with DHA (LD(50) = 200 microg/mL) at different time intervals. The morphological and ultrastructural changes of the treated trophozoites were observed by both light and transmission electron microscopy (TEM). Changes in the cell cycle of the treated cells were observed by flow cytometry. By light microscopy, we observed that DHA-treated trophozoites were detached from the wall of the culture tube and shown bradypraxia and bubbles in the dorsal and ventral surfaces. Ultrastructural observations by TEM revealed that DHA promoted modifications of the cell shape, pronounced dorsal vesiculation, plasma membrane blebbing, disaggregation of ribosomes, depletion of cytoplasmic matrix and heavy deposition of electron-dense precipitates on the cytoplasm and nucleus. The main changes observed in the treated group included the following: (1) trophozoites were rounder in shape and the endoplasmic reticulum was dilated, (2) enlarged trophozoites contained lamella structures and deformed nuclei, (3) trophozoites displayed dissolved cytoplasm with large vacuole spaces or decreased cytoplasmic volume, (4) adhesive disc bubbles or the lamella structures of cytoplasm were clearly observed, and (5) cell division was arrested. Using microscopy and cytometry techniques, we demonstrate that changes in G. lamblia morphology and cell cycle state were induced by DHA. PMID:20422219

Tian, Xi Feng; Shen, Hai E; Li, Ji; Chen, Yang; Yang, Zhi Hong; Lu, Si Qi

2010-07-01

238

Commercial assay for detection of Giardia lamblia and Cryptosporidium parvum antigens in human fecal specimens by rapid solid-phase qualitative immunochromatography.  

Science.gov (United States)

The ImmunoCard STAT! Cryptosporidium/Giardia rapid assay (Meridian Bioscience, Inc.) is a solid-phase qualitative immunochromatographic assay that detects and distinguishes between Giardia lamblia and Cryptosporidium parvum in aqueous extracts of human fecal specimens (fresh, frozen, unfixed, or fixed in 5 or 10% formalin or sodium acetate-acetic acid-formalin). By using specific antibodies, antigens specific for these organisms are isolated and immobilized on a substrate. After the addition of appropriate reagents, a positive test is detected visually by the presence of a gray-black color bar (regardless of the intensity) next to the organism name printed on the test device. A control is included in the device. Steps include tube preparation (buffer, patient specimen, conjugates A and B), testing (addition of sample onto the test device), and visual reading (total time, 12 min). Test performance was evaluated with known positive and negative stool specimens (170 specimens positive for Giardia and 231 specimens negative for Giardia) (85 specimens positive for Cryptosporidium and 316 specimens negative for Cryptosporidium); they were tested with trichrome, iron-hematoxylin, or modified acid-fast stains or the Meridian Bioscience, Inc., Giardia/Cryptosporidium Merifluor combination reagent; specimens with discrepant results were retested by using the Merifluor combination reagent. On the basis of the results of the reference methods, the sensitivities, specificities, and positive and negative predictive values were as follows: for G. lamblia, 93.5, 100, 100, and 95.5%, respectively; for C. parvum, 98.8, 100, 100, and 99.7%, respectively. False-negative results for G. lamblia were obtained with specimens with low parasite numbers (n = 7) or specimens containing trophozoites only (n = 3); one specimen with a false-negative result contained numerous cysts. The one specimen false negative for C. parvum was confirmed to be positive by immunofluorescence. No cross-reactivity was seen with 10 different protozoa (152 challenges), nine different helminths (35 challenges), or human cells (4 challenges) found in fecal specimens. This rapid test system may be very beneficial in the absence of trained microscopists; however, for patients who remain symptomatic after a negative result, the ova and parasite examination and special stains for other coccidia and the microsporidia should always remain options. PMID:12517850

Garcia, Lynne S; Shimizu, Robyn Y; Novak, Susan; Carroll, Marilyn; Chan, Frank

2003-01-01

239

Impaired parasite attachment as fitness cost of metronidazole resistance in Giardia lamblia.  

Science.gov (United States)

Infections with the diarrheagenic protozoan pathogen Giardia lamblia are most commonly treated with metronidazole (Mz). Treatment failures with Mz occur in 10 to 20% of cases and Mz resistance develops in the laboratory, yet clinically, Mz-resistant (Mz(r)) G. lamblia has rarely been isolated from patients. To understand why clinical Mz(r) isolates are rare, we questioned whether Mz resistance entails fitness costs to the parasite. Our studies employed several newly generated and established isogenic Mz(r) cell lines with stable, high-level resistance to Mz and significant cross-resistance to tinidazole, nitazoxanide, and furazolidone. Oral infection of suckling mice revealed that three of five Mz(r) cell lines could not establish infection, while two Mz(r) cell lines infected pups, albeit with reduced efficiencies. Failure to colonize resulted from a diminished capacity of the parasite to attach to the intestinal mucosa in vivo and to epithelial cells and plastic surfaces in vitro. The attachment defect was related to impaired glucose metabolism, since the noninfectious Mz(r) lines consumed less glucose, and glucose promoted ATP-independent parasite attachment in the parental lines. Thus, resistance of Giardia to Mz is accompanied by a glucose metabolism-related attachment defect that can interfere with colonization of the host. Because glucose-metabolizing pathways are important for activation of the prodrug Mz, it follows that a fitness trade-off exists between diminished Mz activation and reduced infectivity, which may explain the observed paucity of clinical Mz(r) isolates of Giardia. However, the data also caution that some forms of Mz resistance do not markedly interfere with in vivo infectivity. PMID:21825286

Tejman-Yarden, Noa; Millman, Maya; Lauwaet, Tineke; Davids, Barbara J; Gillin, Frances D; Dunn, Linda; Upcroft, Jacqueline A; Miyamoto, Yukiko; Eckmann, Lars

2011-10-01

240

Insulin-like growth factors stimulate growth and L-cysteine uptake by the intestinal parasite Giardia lamblia.  

Science.gov (United States)

Giardia lamblia, a parasitic protozoan responsible for diarrhea and malabsorption in humans, grows axenically only in media that contain serum and a high concentration of L-cysteine. During our attempts to grow Giardia in the absence of serum, we found that: (a) human insulin-like growth factors (especially IGF-II), but not insulin, promote the growth and L-cysteine uptake by G. lamblia trophozoites; (b) the growth stimulation was inhibited by alpha IR3, an anti-type 1 IGF receptor monoclonal antibody, but an anti-type 2 IGF receptor antibody had no effect; and (c) IGFs act on Giardia through a type 1 IGF receptor-like protein, which can bind IGF-II with higher affinity than IGF-I, and most likely possesses intrinsic phosphotyrosine kinase activity. PMID:8175729

Luján, H D; Mowatt, M R; Helman, L J; Nash, T E

1994-05-01

 
 
 
 
241

Does breast-feeding protect the child from Giardia lamblia infection?  

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Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Background: Giardia lamblia is one of the most prevalent protozoa infections of the human small intestine. Although anyone can be infected by Giardia, women and children are more susceptible. Giardia infection can cause malnutrition, diarrhea and indigestion of fat. In this study, the effect of breast-feeding on the prevalence of Giardia among children is investigated. "nMethods: A total of 482 children, aged 6 to 24 months, from the urban areas of Semnan, Damghan and Garmsar in Iran, were enrolled in this survey. Each mother underwent an interview and filled out a questionnaire that included mother's age, family size, birth order of the child, age and sex of the child and type of milk consumed, among other variables. Then, each mother was given a sample container with 30cc of phenol alcohol formaldehyde (PAF and an applicator for sampling her child's stool. Each mother was trained to consecutively sample her child's stool for three days, to put the stool into the provided container using the applicator and to shake it until the sample and liquid appeared homogenous. The sample was examined using the direct method, using formalin-ether and thionine. Data was analyzed using the c2 test and logistic regression using SPSS version 11.5."n"nResults: The mean age of the children was 13.6(±5.6 months. Of these children, 45.6% were girls. The prevalence of G. lamblia infection was 8.5%. There was a significant relationship between Giardia and the age of the child, education level of the mother and type of milk the child consumed (p<0.05, such that children who had not consumed their mothers' milk were more likely to be infected compared to those who had been breast fed (OR=2.38, 95% CI: 1.13-5.03, P=0.023."n"nConclusions: Results show that breast-feeding is a safer method of feeding with regard to Giardia infection. Therefore, mothers should be educated to breast-feed their children and not use other types of milk or milk substitutes. This important issue must be considered by policy makers for education and subsidy programs. "n"n Keywords: Giardia lamblia, breast-feeding, formula milk, cow's milk.

Ghorbani R

2008-09-01

242

Use of an Enzyme Immunoassay Does Not Eliminate the Need To Analyze Multiple Stool Specimens for Sensitive Detection of Giardia lamblia  

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The relative sensitivities of a commercially available enzyme immunoassay (EIA) (ProSpecT Giardia; Alexon-Trend Inc., Ramsey, Minn.) and conventional ovum-and-parasite (O&P) examination for the detection of Giardia lamblia in preserved stool specimens were determined. Paired stool samples collected independently within a 7-day period from 103 patients were analyzed by both methods. A total of 54 specimens from 30 patients (18 asymptomatically infected with G. lamblia and 12 with symptoms cons...

Hanson, Kevan L.; Cartwright, Charles P.

2001-01-01

243

Bidirectional transcription is an inherent feature of Giardia lamblia promoters and contributes to an abundance of sterile antisense transcripts throughout the genome  

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A prominent feature of transcription in Giardia lamblia is the abundant production of sterile antisense transcripts (Elmendorf et al. The abundance of sterile transcripts in Giardia lamblia. Nucleic Acids., 29, 4674–4683). Here, we use a computational biology analysis of SAGE data to assess the abundance and distribution of sense and antisense messages in the parasite genome. Sterile antisense transcripts are produced at ?50% of loci with detectable transcription, yet their abundance at a...

Teodorovic, Smilja; Walls, Colleen D.; Elmendorf, Heidi G.

2007-01-01

244

A novel palmitoyl acyl transferase controls surface protein palmitoylation and cytotoxicity in Giardia lamblia.  

Science.gov (United States)

The intestinal protozoan parasite Giardia lamblia undergoes surface antigenic variation whereby one of a family of structurally related variant-specific surface proteins (VSPs) is replaced in a regulated process by another antigenically distinct VSP. All VSPs are type I membrane proteins that have a conserved hydrophobic sequence terminated by the invariant hydrophilic amino acids, CRGKA. Using transfected Giardia constitutively expressing HA-tagged VSPH7 and incubated with radioactive [3H]palmitate, we demonstrate that the palmitate is attached to the Cys in the conserved CRGKA tail. Surface location of mutant VSPs lacking either the CRGKA tail or its Cys is identical to that of wild-type VSPH7 but non-palmitoylated mutants fail to undergo complement-independent antibody specific cytotoxicity. In addition, membrane localization of non-palmitoylated mutant VSPH7 changes from a pattern similar to rafts to non-rafts. Palmitoyl transferases (PAT), responsible for protein palmitoylation in other organisms, often possess a cysteine-rich domain containing a conserved DHHC motif (DHHC-CRD). An open reading frame corresponding to a putative 50 kDa Giardia PAT (gPAT) containing a DHHC-CRD motif was found in the Giardia genome database. Expression of epitope-tagged gPAT using a tetracycline inducible vector localized gPAT to the plasma membrane, a pattern similar to that of VSPs. Transfection with gPAT antisense producing vectors inhibits gPAT expression and palmitoylation of VSPs in vitro confirming the function of gPAT. These results show that VSPs are palmitoylated at the cysteine within the conserved tail by gPAT and indicate an essential function of palmitoylation in control of VSP-mediated signalling and processing. PMID:16262786

Touz, María C; Conrad, John T; Nash, Theodore E

2005-11-01

245

DETECTION OF GIARDIA CYSTS IN DRINKING WATER: STATE-OF-THE-ART  

Science.gov (United States)

Methodology for detecting Giardia cysts in water samples is described. Problems in the collection and processing of samples and in the identification of cysts are discussed. The results of a methodology workshop are presented and a reference method is proposed....

246

Nuclear inheritance and genetic exchange without meiosis in the binucleate parasite Giardia intestinalis  

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The protozoan parasite Giardia intestinalis (also known as Giardia lamblia) is a major waterborne pathogen. During its life cycle, Giardia alternates between the actively growing trophozoite, which has two diploid nuclei with low levels of allelic heterozygosity, and the infectious cyst, which has four nuclei and a tough outer wall. Although the formation of the cyst wall has been studied extensively, we still lack basic knowledge about many fundamental aspects of the cyst, including the sour...

Carpenter, Meredith L.; Assaf, Zoe June; Gourguechon, Ste?phane; Cande, W. Zacheus

2012-01-01

247

Occurrence of Cryptosporidium oocysts and Giardia cysts in water supplies of San Pedro Sula, Honduras  

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Full Text Available During June 1996, water supplies of the city of San Pedro Sula, Honduras, were sampled to obtain an assessment of Cryptosporidium oocyst and Giardia cyst concentrations. Each sample was concentrated and stained with an indirect immunofluorescent antibody, and parasites were counted through microscopic analysis. In three surface water supplies, Cryptosporidium oocyst concentrations ranged from 58 to 260 oocysts per 100 L, and Giardia cysts were present in concentrations ranging from 380 to 2100 cysts per 100 L. Unlike the surface water samples, groundwater had a higher concentration of Cryptosporidium oocysts (26/100 L than Giardia cysts (6/100 L, suggesting that the groundwater aquifer protects the water supply more effectively from larger Giardia cysts. Cryptosporidium oocyst concentrations are within the typical range for surface water supplies in North America whereas Giardia cyst concentrations are elevated. Efforts should be made to protect raw water from sources of contamination.

Solo-Gabriele Helena María

1998-01-01

248

ESTIMATION OF GIARDIA CT VALUES AT HIGH PH FOR THE SURFACE WATER TREATMENT RULE  

Science.gov (United States)

The U.S. Environmental Protection Agency currently recommends Ct (disinfectant concentration multiplied by the exposure time) values to achieve required levels of inactivation of Giardia lamblia cysts by different disinfectants including free chlorine. Current guidance covers ina...

249

Prevalence of Giardia cysts and Cryptosporidium oocysts and characterization of Giardia spp. isolated from drinking water in Canada.  

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This study was carried out to estimate the prevalence and potential for human infectivity of Giardia cysts in Canadian drinking water supplies. The presence of Cryptosporidium oocysts was also noted, but isolates were not collected for further study. A total of 1,760 raw water samples, treated water samples, and raw sewage samples were collected from 72 municipalities across Canada for analysis, 58 of which treat their water by chlorination alone. Giardia cysts were found in 73% of raw sewage...

1996-01-01

250

Characteristics and risk factors for symptomatic Giardia lamblia infections in Germany  

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Full Text Available Abstract Background In developed countries, giardiasis is considered a travel related disease. However, routine surveillance data from Germany indicate that >50% of infections were acquired indigenously. We studied the epidemiological characteristics of symptomatic Giardia infections acquired in Germany and abroad, and verified the proportion of cases acquired in Germany in order to investigate risk factors for sporadic autochthonous Giardia infections. Methods We identified Giardia cases notified by 41 local health authorities between February 2007 and January 2008 and interviewed them on their clinical symptoms, underlying morbidities, travel abroad and potential risk factors for the disease. We conducted a case-control-study including laboratory-confirmed (microscopy or antigen-test autochthonous Giardia cases with clinical manifestations (diarrhoea, cramps, bloating and randomly selected controls from the local population registry matched by county of residence and age-group (0-5, 6-19, ?20 years. Secondary cases, controls with diarrhoea and persons who had travelled outside Germany in the three weeks prior to disease onset (exposure period were excluded. We calculated adjusted odds ratios (aOR with 95% confidence intervals (CI using conditional logistic regression. Results Of 273 interviewed cases, 131 (48% had not travelled abroad during the defined exposure period. Of these 131, 85 (65% were male, 68 (54% were living in communities with >100,000 inhabitants and 107 (83% were aged 20 years or older. We included 120 cases and 240 controls in the case-control study. Cases were more likely to be male (aOR 2.5 CI 1.4-4.4, immunocompromised (aOR 15.3 CI 1.8-127 and daily consumers of green salad (aOR 2.9 CI 1.2-7.2. Contact with animals (pets/farm animals and exposure to surface water (swimming/water sports were not associated with symptomatic disease. Conclusions A substantial proportion of Giardia lamblia cases in Germany are indigenously acquired. Symptomatic cases are significantly more likely to be immunocompromised than control persons from the general population. Physicians should consider Giardia infections among patients with no recent history of travel abroad, particularly if they have immune deficiencies. Green salads may be an important vehicle of infection. Information campaigns highlighting this food-borne risk should emphasise the risk to persons with immune deficiencies.

Stark Klaus

2010-01-01

251

An unusually compact ribosomal DNA repeat in the protozoan Giardia lamblia.  

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The ribosomal RNA (rRNA) genes of the protozoan parasite Giardia lamblia have been analyzed with respect to size, composition and copy number. They are found to be remarkable in several respects. First, the rRNAs themselves are the smallest yet reported for any eukaryotic organism. Second, the genes encoding them are found as an exceptionally small tandemly repeated unit of only 5.4 kilobase-pairs. Third, the genes are extraordinarily G:C rich, even in regions which are highly conserved between all other eukaryotic rRNA genes. Finally, by analogy to other organisms, the 5.8S RNA appears to lack about 15 nucleotides from its 3'-end, a region previously thought to be essential for 5.8S RNA function. We also provide the first estimates of the genomic complexity and total G:C content of this important protozoan pathogen. PMID:3588284

Boothroyd, J C; Wang, A; Campbell, D A; Wang, C C

1987-05-26

252

In situ analyses reveal that the two nuclei of Giardia lamblia are equivalent.  

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The protozoan parasite Giardia lamblia has the unusual morphology of bearing two equal-sized nuclei. This organism probably represents the earliest diverging lineage of eukaryotes, suggesting that its biological tactics may be transitional. To begin to understand the role played by the two equal-sized nuclei in this organism, and perhaps the role this organism has played along the path to higher eukaryotes, we have analyzed the structure and function of these two nuclei. We show that the two nuclei are equivalent with respect to the amount of DNA harbored in each nucleus, the presence of ribosomal DNA sequences, and the transcriptional activity. We begin also to address the question of how these bilaterally symmetrical ancestors divide, by illustrating the mitotic plane of division. PMID:2384520

Kabnick, K S; Peattie, D A

1990-03-01

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Giardia lamblia Transcriptome Analysis Using TSS-Seq and RNA-Seq  

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Giardia lamblia is a protozoan parasite that is found worldwide and has both medical and veterinary importance. We applied the transcription start sequence (TSS-seq) and RNA sequence (RNA-seq) techniques to study the transcriptome of the assemblage A WB strain trophozoite. We identified 8000 transcription regions (TR) with significant transcription. Of these regions, 1881 TRs were more than 500 nucleotides upstream of an annotated ORF. Combining both techniques helped us to identify 24 ORFs that should be re-annotated and 60 new ORFs. From the 8000 TRs, we were able to identify an AT-rich consensus that includes the transcription initiation site. It is possible that transcription that was previously thought to be bidirectional is actually unidirectional.

Tolba, Mohammed E. M.; Kobayashi, Seiki; Imada, Mihoko; Suzuki, Yutaka; Sugano, Sumio

2013-01-01

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Ozonoterapia en el síndrome de malabsorción intestinal secundario a parasitismo por Giardia lamblia: estudio preliminar  

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Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish Se estudió el efecto de la ozonoterapia combinada (OLEOZON® oral y ozonoterapia rectal) en el síndrome de malabsorción intestinal, secundario a parasitismo intestinal por Giardia lamblia. Se tomaron 186 pacientes y se formaron 3 grupos de 62 pacientes cada uno. El primer grupo se trató con metronida [...] zol y vitaminoterapia, el segundo con OLEOZON® oral y vitaminoterapia y el tercero con ozonoterapia combinada y vitaminoterapia. Los pacientes fueron evaluados clínicamente por drenaje biliar y biopsia de yeyuno al inicio y final del tratamiento. Se alcanzó una mejoría importante en el tercer grupo (66,1 %), de los cuales, los diagnosticados tempranamente, 40,3 % obtuvo su curación. Se concluyó que la ozonoterapia combinada puede ser eficaz en esta patología. Abstract in english The effect of combined ozone therapy (oral OLEOZON® and rectal ozone therapy) on the syndrome of intestinal malabsorption secondary to intestinal parasitism caused by Giardia lamblia was studied. 186 patients were selected and dividided into 3 groups of 62 patients each. The first group was treated [...] with metronidazole and vitamin therapy, the second with oral OLEOZON® and vitamin therapy, and the third with combined ozone therapy and vitamin therapy. The patients were clinically evaluated by biliary drainage and jejunum biopsy at the beginning and at the end of the treatment. A significant improvement was observed in the third group (66.1 %). Of them, those that had been early diagnosed were cured (40.3 %). It was concluded that combined ozone therapy may be efficient in this pathology.

Nazarina Ivonne, Méndez Pérez; José L., Calunga Fernández; Silvia, Menéndez Cepero.

255

Efecto de un extracto de Petiveria Alliacea Lin sobre el crecimiento de Giardia lamblia in vitro  

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Full Text Available Se evaluó el efecto de un extracto fluido elaborado con un menstruo de Petiveria alliacea (anamú sobre el crecimiento in vitro de Giardia lamblia. Para este ensayo se empleó una cepa aislada en el Instituto de Medicina Tropical "Pedro Kourí", procedente de un paciente infestado. Los cultivos fueron incubados a 37 °C durante 48 h y posteriormente ajustada su concentración a 2 ´105 parásitos por 0,5 mL. Los resultados obtenidos muestran un marcado efecto antigiardiásico, por los altos porcentajes inhibitorios del crecimiento con las 5 concentraciones probadas (17,2; 4,3; 1,075; 0,54 y 0,135 mg/mL, que alcanzó el 96,81 % con la mayor concentración y el 5,03 % con la de 0,135 mg/mL. La concentración media inhibitoria resultó de 2,05 mg/mL.The effect of a fluid extract made with a menstruum of Petiveria alliacea (anamú on the growth of Giardia lamblia in vitro was evaluated. A strain isolated from an infected patient at “Pedro Kouri” Institute of Tropical Medicine was used in this trial. The cultures were incubated at 37 ºC during 48 hours and later their concentrations of 2 x 105 parasites per 0.5 mL were adjusted. The results obtained showed a marked antigiardiasis effect due to the high inhibitory percentages of growth with the 5 tested concentrations (17.2; 4.3; 1.075; 0.54 and 0.135 mg//mL. An effect of 96.81 % was attained with the highest concentration and of 5.03 % with the concentration of 0.135 mg/mL. The mean inhibitory concentration was 2.05 mg/mL.

Aimée Echevarría

2001-09-01

256

Efecto de un extracto de Petiveria Alliacea Lin sobre el crecimiento de Giardia lamblia in vitro  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish Se evaluó el efecto de un extracto fluido elaborado con un menstruo de Petiveria alliacea (anamú) sobre el crecimiento in vitro de Giardia lamblia. Para este ensayo se empleó una cepa aislada en el Instituto de Medicina Tropical "Pedro Kourí", procedente de un paciente infestado. Los cultivos fueron [...] incubados a 37 °C durante 48 h y posteriormente ajustada su concentración a 2 ´105 parásitos por 0,5 mL. Los resultados obtenidos muestran un marcado efecto antigiardiásico, por los altos porcentajes inhibitorios del crecimiento con las 5 concentraciones probadas (17,2; 4,3; 1,075; 0,54 y 0,135 mg/mL), que alcanzó el 96,81 % con la mayor concentración y el 5,03 % con la de 0,135 mg/mL. La concentración media inhibitoria resultó de 2,05 mg/mL. Abstract in english The effect of a fluid extract made with a menstruum of Petiveria alliacea (anamú) on the growth of Giardia lamblia in vitro was evaluated. A strain isolated from an infected patient at “Pedro Kouri” Institute of Tropical Medicine was used in this trial. The cultures were incubated at 37 ºC during 48 [...] hours and later their concentrations of 2 x 105 parasites per 0.5 mL were adjusted. The results obtained showed a marked antigiardiasis effect due to the high inhibitory percentages of growth with the 5 tested concentrations (17.2; 4.3; 1.075; 0.54 and 0.135 mg//mL). An effect of 96.81 % was attained with the highest concentration and of 5.03 % with the concentration of 0.135 mg/mL. The mean inhibitory concentration was 2.05 mg/mL.

Aimée, Echevarría; Dinorah, Torres Idavoy.

257

Impact of Helicobacter pylori and Giardia lamblia infections on chronic urticaria.  

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The etiology of chronic urticaria is largely unknown. The role of Helicobacter pylori infection, which is the most important cause of gastritis and peptic ulcer, is not clear in the pathophysiology of chronic urticaria. In this study, we aimed to define the impact of H. pylori on chronic urticaria. Thirty-eight patients who had chronic urticaria of unknown origin and dyspepsia were included in the study. In all patients, standard laboratory tests for detection of urticaria etiology were performed. Mean urticaria symptom scores of patients were carried out. All patients underwent upper gastrointestinal endoscopy. The presence of H. pylori was investigated using urease testing and histopathology. Duodenal fluid aspirated during upper endoscopy was examined for the presence of Giardia lamblia. H. pylori infection was detected in 29 patients. After successful eradication of H. pylori infection, the mean symptom score of patients did not change significantly (2.6 +/- 0.6 vs., 2.4 +/- 0.8). Only one patient had a total disappearance of urticaria symptoms. Out of 38 patients, only one had G. lamblia infection. The results of our study suggest that there is no association between H. pylori infection and chronic urticaria. PMID:10879997

Erel, F; Sener, O; Erdil, A; Karaayvaz, M; Gür, G; Caliskaner, Z; Ozangüç, N

2000-01-01

258

COMPARISON OF TWO METHODS FOR DETECTION OF GIARDIA CYSTS AND CRYTOSPORIDIUM OOCYSTS IN WATER  

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The steps of two immunofluorescent-antibody-based detection methods were evaluated for their efficiencies in detecting Giardia cysts and Cryptosporidium oocysts. The two methods evaluated were the American Society for Testing and Materials proposed test method for Giardia cysts a...

259

DETECTION AND IDENTIFICATION OF 'GIARDIA' CYSTS USING IMMUNOFLUORESCENCE AND PHASE CONTRAST MICROSCOPY  

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Detection and identification of Giardia cysts in water samples has been improved by the development of an immunofluorescent method that specifically stains Giardia cysts bright green and allows their easy detection against a black background. The report discusses aspects of the m...

260

X-ray structure and characterization of carbamate kinase from the human parasite Giardia lamblia.  

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Carbamate kinase catalyzes the reversible conversion of carbamoyl phosphate and ADP to ATP and ammonium carbamate, which is hydrolyzed to ammonia and carbonate. The three-dimensional structure of carbamate kinase from the human parasite Giardia lamblia (glCK) has been determined at 3 A resolution. The crystals belonged to the monoclinic space group P2(1), with unit-cell parameters a = 69.77, b = 85.41, c = 102.1 A, beta = 106.8 degrees . The structure was refined to a final R factor of 0.227. The essentiality of glCK together with its absence in humans makes the enzyme an attractive candidate for anti-Giardia drug development. Steady-state kinetic rate constants have been determined. The k(cat) for ATP formation is 319 +/- 9 s(-1). The K(m) values for carbamoyl phosphate and ADP are 85 +/- 6 and 70 +/- 5 microM, respectively. The structure suggests that three invariant lysine residues (Lys131, Lys216 and Lys278) may be involved in the binding of substrates and phosphoryl transfer. The structure of glCK reveals that a glycerol molecule binds in the likely carbamoyl phosphate-binding site. PMID:20383005

Galkin, Andrey; Kulakova, Liudmila; Wu, Rui; Nash, Theodore E; Dunaway-Mariano, Debra; Herzberg, Osnat

2010-04-01

 
 
 
 
261

Giardia lamblia EB1 is a functional homolog of yeast Bim1p that binds to microtubules.  

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Giardia lamblia, with two nuclei and a distinct polarized morphology, is an interesting organism for investigating how distribution of its microtubule (MT) is controlled during its cell cycle. In this study, we identified the end-binding protein 1 (EB1) of G. lamblia, a well-known microtubule-associated protein that organizes MTs in eukaryotes. Immunofluorescence assays using recombinant EB1 (rEB1)-specific antibodies demonstrated EB1 localization in nuclear membrane as well as in some cytoskeletal structures such as axomenes and median bodies of trophozoites of G. lamblia. Complementation experiments using the BIM1 knock-out mutant of yeast, the yeast homolog of mammalian EB1, showed that giardial EB1 was able to carry out a homologous function in controlling MT dynamics. In addition, rEB1 of G. lamblia co-precipitated with MTs by an in vitro binding assay, thereby demonstrating that G. lamblia EB1 is a MT-associated protein. These results, taken together, suggest that G. lamblia EB1 is a functional homolog of eukaryotic EB1 and is likely to be a determinant for MT distribution. PMID:18590831

Kim, Juri; Sim, Seobo; Kim, Junwon; Song, Kiwon; Yong, Tai-Soon; Park, Soon-Jung

2008-12-01

262

Aislamiento y axenización de Giardia lamblia en niños procedentes de círculos infantiles de Ciudad de La Habana  

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Full Text Available Se reporta el aislamiento de Giardia lamblia procedentes de niños de 3 círculos infantiles de Ciudad de La Habana. El 2,8 % de los aislamientos fue logrado utilizando la desenquistación in vitro, mientras que utilizando al gerbil como modelo animal para la desenquistación del parásito se logró el 97,2 %, lo que demostró la superioridad de este último método.It is reported the isolation of Giardia lamblia in children from three day care centers in Havana City. The 2,8 % of the isolations were obtained by using the disencystment in vitro, whereas using gerbil as an animal model for the parasite disencystment 97,2 % was attained. This result shows the superiority ot he latter.

Dinorah Torres

1996-12-01

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Oxidative stress-induced cell cycle blockage and a protease-independent programmed cell death in microaerophilic Giardia lamblia  

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Giardia lamblia is a microaerophilic human gastrointestinal parasite and considered as an early-diverged eukaryote. In vitro oxidative stress generation plays a significant role in cell cycle progression and cell death of this parasite. In the present study hydrogen peroxide, metronidazole, and a modified growth medium without cysteine and ascorbic acid have been chosen as oxidative stress-inducing agents. Cell cycle progression has been found to be regulated by different types of oxidative s...

Ghosh, Esha; Ghosh, Arjun; Ghosh, Amar Nath; Nozaki, Tomoyoshi; Ganguly, Sandipan

2009-01-01

264

Comparison of Nine Commercially Available Enzyme-Linked Immunosorbent Assays for Detection of Giardia lamblia in Fecal Specimens  

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Overall performance, including ease of use, total hands-on time, incubation and processing times, sensitivity, and specificity, of each of nine enzyme-linked immunosorbent assays (ELISAs) were compared by using 222 individual fecal samples submitted for the detection of Giardia lamblia. The assays evaluated were manufactured by Alexon, Inc., Cambridge Biotech Corp., Meridian, Inc., and Trend Scientific, Inc. All assays used polyclonal antibodies except the “new and improved” Microplate (d...

Aldeen, William E.; Carroll, K.; Robison, A.; Morrison, M.; Hale, D.

1998-01-01

265

SUMOylation in Giardia lamblia: A Conserved Post-Translational Modification in One of the Earliest Divergent Eukaryotes  

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Post-translational modifications are able to regulate protein function and cellular processes in a rapid and reversible way. SUMOylation, the post-translational modification of proteins by the addition of SUMO, is a highly conserved process that seems to be present in modern cells. However, the mechanism of protein SUMOylation in earlier divergent eukaryotes, such as Giardia lamblia, is only starting to become apparent. In this work, we report the presence of a single SUMO gene encoding to SU...

Vranych, Cecilia V.; Merino, Mari?a C.; Nahuel Zamponi; Touz, Mari?a C.; Ro?polo, Andrea S.

2012-01-01

266

Virtual Screening of Combinatorial Libraries across a Gene Family: in Search of Inhibitors of Giardia lamblia Guanine Phosphoribosyltransferase  

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Parasitic protozoa lack the ability to synthesize purine nucleotides de novo, relying instead on purine salvage enzymes for their survival. Guanine phosphoribosyltransferase (GPRT) from the protozoan parasite Giardia lamblia is a potential target for rational antiparasitic drug design, based on the experimental evidence, which indicates the lack of interconversion between adenine and guanine nucleotide pools. The present study is a continuation of our efforts to use three-dimensional structur...

Aronov, Alex M.; Munagala, Narsimha R.; Kuntz, Irwin D.; Wang, Ching C.

2001-01-01

267

Oxidative stress-induced cell cycle blockage and a protease-independent programmed cell death in  microaerophilic Giardia lamblia  

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Esha Ghosh1, Arjun Ghosh1, Amar Nath Ghosh2, Tomoyoshi Nozaki3, Sandipan Ganguly11Division of Parasitology; 2Division of Electron Microscopy, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India; 3Division of Parasitology, National Institute of Infectious Diseases, Tokyo, JapanAbstract: Giardia lamblia is a microaerophilic human gastrointestinal parasite and considered as an early-diverged eukaryote. In vitro oxidative stress generation plays a significa...

Esha Ghosh; Arjun Ghosh; Amar Nath Ghosh; Tomoyoshi Nozaki; Sandipan Ganguly

2009-01-01

268

Adhesion of Cryptosporidium parvum and Giardia lamblia to solid surfaces: the role of surface charge and hydrophobicity  

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Adhesion of Cryptosporidium parvum and Giardia lamblia to four materials of different surface charge and hydrophobicity was investigated. Glass beads were used with and without three polymer coatings: aminosilines (A0750), fluorosilines (T2494), an amino cationic polymer. Surface charge density and hydrophobicity of the beads were characterized by measuring the zeta potential (ZP) and the contact angle, respectively. Adhesion was derived from batch experiments where negatively charged (oo)cys...

Dai, X.; Boll, J.; Hayes, M. E.; Aston, D. E.

2004-01-01

269

ELISA y técnica de sedimentación espontánea para el diagnóstico de infección por Giardia lamblia en muestras fecales de niños de Perú ELISA and spontaneous sedimentation technique for the diagnosis of Giardia lamblia infection in stool samples of Peruvian children  

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Full Text Available OBJETIVO: Comparar un kit ELISA comercial para coproantígenos y la técnica de sedimentación espontánea en tubo (TSET para el diagnóstico de Giardia lamblia en muestras fecales de niños de una zona endémica peruana. MATERIAL Y MÉTODOS: Fueron analizadas 174 muestras mediante la TSET y el kit Giardia 2nd Generation ELISA. RESULTADOS: Fueron positivas 51 muestras por ELISA y 49 por TSET. CONCLUSIONES: El ELISA resultó ser altamente sensible y específico, sencillo y rápido; sin embargo, la muy buena concordancia, alta precisión, bajo costo y capacidad para detectar otros enteroparásitos hace que la TSET sea recomendable para el diagnóstico en zonas endémicas del Perú.OBJETIVE: To compare a commercial coproantigen ELISA kit and the technique of spontaneous sedimentation in tube (TSET for the diagnosis of Giardia lamblia in fecal specimens from children in a Peruvian endemic area. MATERIAL AND METHODS: 174 fecal samples were analyzed by TSET and 2nd Generation Giardia ELISA kit. RESULTS: 51 samples were positive by ELISA and 49 by TSET. CONCLUSIONS: The ELISA was highly sensitive and specific, simple and fast. However, the very good agreement, high precision, low cost and ability to detect other intestinal parasites makes use of TSET recommended for laboratory diagnosis in endemic areas of Peru.

Claudia Rodríguez-Ulloa

2011-12-01

270

Oxidative stress-induced cell cycle blockage and a protease-independent programmed cell death in  microaerophilic Giardia lamblia  

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Full Text Available Esha Ghosh1, Arjun Ghosh1, Amar Nath Ghosh2, Tomoyoshi Nozaki3, Sandipan Ganguly11Division of Parasitology; 2Division of Electron Microscopy, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India; 3Division of Parasitology, National Institute of Infectious Diseases, Tokyo, JapanAbstract: Giardia lamblia is a microaerophilic human gastrointestinal parasite and considered as an early-diverged eukaryote. In vitro oxidative stress generation plays a significant role in cell cycle progression and cell death of this parasite. In the present study hydrogen peroxide, metronidazole, and a modified growth medium without cysteine and ascorbic acid have been chosen as oxidative stress-inducing agents. Cell cycle progression has been found to be regulated by different types of oxidative stresses. Apoptosis is not an established pathway in Giardia, which is devoid of ideal mitochondria, but in the present investigation, apoptosis-like programmed cell death has been found by the experiments like AnnexinV-FITC assay, DNA fragmentation pattern, etc. On the contrary, Caspase-9 assay, which confirms the caspase-mediated apoptotic pathway, has been found to be negative in all the stress conditions. Protease inhibitor assay confirmed that, even in absence of any proteases, programmed cell death does occur in this primitive eukaryote. All these results signify a novel pathway of programmed suicidal death in Giardia lamblia under oxidative stress. This is the first demonstration of protease-independent programmed cell death regulation in Giardia exclusive for its own specialties.Keywords: Giardia lamblia, oxidative stress, reactive oxygen species, programmed cell death, apoptosis, early branching eukaryotes

Esha Ghosh

2009-03-01

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Giardia lamblia e alergia respiratória: estudo em uma amostra de crianças de área urbana com frequência elevada da protozoose / Giardia lamblia and respiratory allergies: a study of children from an urban area with a high incidence of protozoan infections  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Uma elevada incidência de enteroparasitoses é encontrada em regiões urbanas do nordeste brasileiro. As infecções por Giardia lamblia têm sido relacionadas com aumento da prevalência de alergias cutâneas e gastrointestinais. Contudo, ainda existe pouca informação sobre a associação entre a [...] giardíase e doenças alérgicas das vias aéreas. Diante disso, o presente estudo se propôs a verificar a relação entre a infecção por G. lamblia em crianças de área urbana e reatividade alérgica respiratória. MÉTODOS: O estudo incluiu 110 pacientes, de ambos os sexos e idades, entre 5 e 15 anos. Os pacientes foram submetidos a questionários de avaliação dos sintomas clínicos, testes cutâneos de leitura imediata e exames coproparasitológicos e sorológicos. RESULTADOS: Foi verificada uma frequência elevada de crianças infectadas por G. lamblia (45%, 50/110). A infecção pelo protozoário não foi associada com maior risco de alergias respiratórias (p = 0,075), elevação de IgE total (p = 0,701), IgE específica (p = 0,250) ou teste cutâneo positivo para diferentes alérgenos ambientais (p = 0,239). CONCLUSÃO: O estudo demonstrou que a presença dos sintomas de asma, atopia cutânea e marcadores sorológicos não foram associados com a presença de infecção pela G. lamblia nessa amostra de crianças. Abstract in english OBJECTIVES: There is a high incidence of intestinal parasite infection in urban areas in the Northeast of Brazil. Giardia lamblia infections have been associated with increased prevalence of cutaneous allergies and gastrointestinal disorders. However, little is known about the relationship between g [...] iardiasis and allergic diseases of the airways. The present study aimed to investigate the possible association between respiratory allergic diseases and infections by G. lamblia in children from urban areas. METHODS: This study recruited 110 patients of both sexes aged 5-15 years. Patients were administered a questionnaire evaluating clinical symptoms and were given skin tests, parasite tests and serum tests. RESULTS: A high incidence of G. lamblia was observed (45%, 50/110). Infections by this protozoan were not associated with increased risk of respiratory allergy (p = 0.075), high total IgE levels (p = 0.701), positive specific IgE tests (p = 0.250), or positive skin tests for a range of environmental allergens (p = 0.239). CONCLUSION: This study demonstrated that symptoms of asthma, skin allergy and serum markers were not associated with G. lamblia infections in this sample of children from urban areas.

Valdênia M. O., Souza; Iana R. F., Sales; Décio M., Peixoto; Vláudia M. Assis, Costa; José A., Rizzo; Almerinda R., Silva; Roberta Faria, Camilo; Felipe Faria, Pierotti; Dirceu, Solé; Emanuel S. C., Sarinho.

272

Synchronisation of Giardia lamblia: identification of cell cycle stage-specific genes and a differentiation restriction point.  

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The intestinal parasite Giardia lamblia undergoes cell differentiations that entail entry into and departure from the replicative cell cycle. The pathophysiology of giardiasis depends directly upon the ability of the trophozoite form to replicate in the host upper small intestine. Thus, cell proliferation is tightly linked to disease. However, studies of cell cycle regulation in Giardia have been hampered by the inability to synchronise cultures. Here we report that Giardia isolates of the major human genotypes A and B can be synchronised using aphidicolin, a mycotoxin that reversibly inhibits replicative DNA polymerases in eukaryotic cells. Aphidicolin arrests Giardia trophozoites in the early DNA synthesis (S) phase of the cell cycle. We identified a set of cell cycle orthologues in the Giardia genome using bioinformatic analyses and showed that synchronised parasites express these genes in a cell cycle stage-specific manner. The synchronisation method also showed that during encystation, exit from the ordinary cell cycle occurs preferentially in G(2) and defines a restriction point for differentiation. Synchronisation opens up possibilities for further molecular and cell biological studies of chromosome replication, mitosis and segregation of the complex cytoskeleton in Giardia. PMID:18289546

Reiner, David S; Ankarklev, Johan; Troell, Karin; Palm, Daniel; Bernander, Rolf; Gillin, Frances D; Andersson, Jan O; Svärd, Staffan G

2008-07-01

273

DETERMINATION OF 'GIARDIA MURIS' CYST VIABILITY BY DIFFERENTIAL INTERFERENCE CONTRAST, PHASE, OR BRIGHTFIELD MICROSCOPY  

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Recent experiments have demonstrated that fluorogenic substrates are taken up by Giardia cysts and that an excellent correlation exists between animal infectivity and vital staining with fluorescein diacetate (FDA) for viable cysts and propidium iodide (PI) for non-viable cysts. ...

274

ELISA y técnica de sedimentación espontánea para el diagnóstico de infección por Giardia lamblia en muestras fecales de niños de Perú / ELISA and spontaneous sedimentation technique for the diagnosis of Giardia lamblia infection in stool samples of Peruvian children  

Scientific Electronic Library Online (English)

Full Text Available SciELO Public Health | Language: Spanish Abstract in spanish OBJETIVO: Comparar un kit ELISA comercial para coproantígenos y la técnica de sedimentación espontánea en tubo (TSET) para el diagnóstico de Giardia lamblia en muestras fecales de niños de una zona endémica peruana. MATERIAL Y MÉTODOS: Fueron analizadas 174 muestras mediante la TSET y el kit Giardia [...] 2nd Generation ELISA. RESULTADOS: Fueron positivas 51 muestras por ELISA y 49 por TSET. CONCLUSIONES: El ELISA resultó ser altamente sensible y específico, sencillo y rápido; sin embargo, la muy buena concordancia, alta precisión, bajo costo y capacidad para detectar otros enteroparásitos hace que la TSET sea recomendable para el diagnóstico en zonas endémicas del Perú. Abstract in english OBJETIVE: To compare a commercial coproantigen ELISA kit and the technique of spontaneous sedimentation in tube (TSET) for the diagnosis of Giardia lamblia in fecal specimens from children in a Peruvian endemic area. MATERIAL AND METHODS: 174 fecal samples were analyzed by TSET and 2nd Generation Gi [...] ardia ELISA kit. RESULTS: 51 samples were positive by ELISA and 49 by TSET. CONCLUSIONS: The ELISA was highly sensitive and specific, simple and fast. However, the very good agreement, high precision, low cost and ability to detect other intestinal parasites makes use of TSET recommended for laboratory diagnosis in endemic areas of Peru.

Claudia, Rodríguez-Ulloa; Marco, Rivera-Jacinto.

275

ELISA y técnica de sedimentación espontánea para el diagnóstico de infección por Giardia lamblia en muestras fecales de niños de Perú / ELISA and spontaneous sedimentation technique for the diagnosis of Giardia lamblia infection in stool samples of Peruvian children  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish OBJETIVO: Comparar un kit ELISA comercial para coproantígenos y la técnica de sedimentación espontánea en tubo (TSET) para el diagnóstico de Giardia lamblia en muestras fecales de niños de una zona endémica peruana. MATERIAL Y MÉTODOS: Fueron analizadas 174 muestras mediante la TSET y el kit Giardia [...] 2nd Generation ELISA. RESULTADOS: Fueron positivas 51 muestras por ELISA y 49 por TSET. CONCLUSIONES: El ELISA resultó ser altamente sensible y específico, sencillo y rápido; sin embargo, la muy buena concordancia, alta precisión, bajo costo y capacidad para detectar otros enteroparásitos hace que la TSET sea recomendable para el diagnóstico en zonas endémicas del Perú. Abstract in english OBJETIVE: To compare a commercial coproantigen ELISA kit and the technique of spontaneous sedimentation in tube (TSET) for the diagnosis of Giardia lamblia in fecal specimens from children in a Peruvian endemic area. MATERIAL AND METHODS: 174 fecal samples were analyzed by TSET and 2nd Generation Gi [...] ardia ELISA kit. RESULTS: 51 samples were positive by ELISA and 49 by TSET. CONCLUSIONS: The ELISA was highly sensitive and specific, simple and fast. However, the very good agreement, high precision, low cost and ability to detect other intestinal parasites makes use of TSET recommended for laboratory diagnosis in endemic areas of Peru.

Claudia, Rodríguez-Ulloa; Marco, Rivera-Jacinto.

276

An unusual triosephosphate isomerase from the early divergent eukaryote Giardia lamblia.  

Science.gov (United States)

Recombinant triosephosphate isomerase from the parasite Giardia lamblia (GlTIM) was characterized and immunolocalized. The enzyme is distributed uniformly throughout the cytoplasm. Size exclusion chromatography of the purified enzyme showed two peaks with molecular weights of 108 and 55 kDa. Under reducing conditions, only the 55-kDa protein was detected. In denaturing gel electrophoresis without dithiothreitol, the enzyme showed two bands with molecular weights of 28 and 50 kDa; with dithiotretitol, only the 28-kDa protein was observed. These data indicate that GlTIM may exist as a tetramer or a dimer and that, in the former, the two dimers are covalently linked by disulfide bonds. The kinetics of the dimer were similar to those of other TIMs. The tetramer exhibited half of the kcat of the dimer without changes in the Km. Studies on the thermal stability and the apparent association constants between monomers showed that the tetramer was slightly more stable than the dimer. This finding suggests the oligomerization is not related to enzyme thermostability as in Thermotoga maritima. Instead, it could be that oligomerization is related to the regulation of catalytic activity in different states of the life cycle of this mesophilic parasite. PMID:15146481

López-Velázquez, Gabriel; Molina-Ortiz, Dora; Cabrera, Nallely; Hernández-Alcántara, Gloria; Peon-Peralta, Jorge; Yépez-Mulia, Lilian; Pérez-Montfort, Ruy; Reyes-Vivas, Horacio

2004-06-01

277

Giardia lamblia expresses a proteobacterial-like DnaK homolog.  

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We identified a novel gene encoding molecular chaperone HSP70 in the amitochondriate parasite Giardia lamblia. The predicted protein is similar to bacterial DnaK and mitochondrial HSP70s. The gene is transcribed and translated at a constant level during trophozoite growth and encystation. Alignment of the sequence with a data set of cytosolic, endoplasmic reticulum (ER), mitochondrial, and DnaK HSP70 homologs indicated that the sequence was extremely divergent and contained insertions unique to giardial HSP70s. Phylogenetic analyses demonstrated that this sequence was distinct from the cytosolic and ER forms and was most similar to proteobacterial and mitochondrial DnaKs. However, a specific relationship with the alpha proteobacterial and mitochondrial sequences was not strongly supported by phylogenetic analyses of this data set, in contrast to similar analyses of cpn60. These data neither confirm nor reject the possibility that this gene is a relic of secondary mitochondrial loss; they leave open the possibility that it was acquired in a separate endosymbiotic event. PMID:11264404

Morrison, H G; Roger, A J; Nystul, T G; Gillin, F D; Sogin, M L

2001-04-01

278

Evaluation Of Cytokines Changes In Patients Infected With Giardia lamblia In Comparison With Healthy Subjects  

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Full Text Available Background and Aim: Human Giardisis infection is caused by the flagellate protozoa. Giardia lamblia, which lives in the small intestine, causing damage and may also cause gastrointestinal symptoms. This parasitic disease has a worldwide distribution and prevalence varies from 5% to 30%. The role of both humeral and cellular immune response in the host defense against parasites has proven. Since an immune response is directly affected by cytokine, study of cytokines changes in patients with giardiosis is of particular importance. Materials and Methods: In this study the serum levels of IL-2 - 4 - 6 to 17 and 23 in patients and healthy subjects were measured and compared. Fasting blood samples were taken from the volunteers, ELISA was performed to measure cytokines. Results: In this study, the amount of IL-2 and IL-6 in infected patients was significantly more than the controls, but IL-4 levels were significantly lower in infected individuals (P=0.0001. Also for the first time in people with giardiasis IL-17 and IL-23 was measured and there was a significant aifference in these cytokines between the infected patients healthy controls(respectively P=0.044 and P=0.03 Conclusion: Host defense response against parasitic infections, is directly and affected by cytokines. Increased interleukin 2, 6, 17 and 23 in patients with Giardiosis was probably caused by immune response and local intestinal inflammation.

Mitra Zarebavani

2012-12-01

279

FILTRATION OF 'GIARDIA' CYSTS AND OTHER SUBSTANCES. VOLUME 1. DIATOMACEOUS EARTH FILTRATION  

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The effectiveness of diatomaceous earth filtration of drinking water was studied under various operating conditions for removal of Giardia cysts, total coliform bacteria, standard plate count bacteria, turbidity, and particles. Seven grades of diatomaceous earth were used. Temper...

280

EVALUATION OF CRYPTOSPORIDIUM OOCYSTS AND GIARDIA CYSTS IN A WATERSHED RESERVOIR  

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This investigation evaluated the occurrence of Cryptosporidium oocysts and Giardia cysts at 17 sampling locations in Lake Texoma reservoir using method 1623 with standard Envirocheck" capsule filters. The watershed serves rural agricultural communities active in cattle ranching,...

 
 
 
 
281

vsp Gene Expression by Giardia lamblia Clone GS/M-83-H7 during Antigenic Variation In Vivo and In Vitro  

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Giardia lamblia infections are associated with antigenic variation of the parasite, which is generated by a continuous change of the variant-specific surface proteins (VSPs). Many investigations on the process of antigenic variation were based on the use of G. lamblia clone GS/M-83-H7, which expresses VSP H7 as its major surface antigen. In the present study, mice were infected with the aforementioned clonal line to investigate vsp gene expression during the complex process of antigenic varia...

Bienz, M.; Siles-lucas, M.; Wittwer, P.; Mu?ller, N.

2001-01-01

282

Effects of Dietary Zinc Manipulation on Growth Performance, Zinc Status and Immune Response during Giardia lamblia Infection: A Study in CD-1 Mice  

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Associations between Giardia lamblia infection and low serum concentrations of zinc have been reported in young children. Interestingly, relatively few studies have examined the effects of different dietary zinc levels on the parasite-infected host. The aims of this study were to compare the growth performance and zinc status in response to varying levels of dietary zinc and to measure the antibody-mediated response of mice during G. lamblia infection. Male CD-1 mice were fed using 1 of 4 exp...

Gemma Iñigo-Figueroa; Me?ndez-estrada, Rosa O.; Luis Quihui-Cota; Vela?squez-contreras, Carlos A.; Adriana Garibay-Escobar; Rafael Canett-Romero; Humberto Astiazarán-García

2013-01-01

283

Non-specific reactions in enzyme linked immunosorbent assays for serum antibody to entamoeba histolytica and Giardia lamblia in non-endemic areas.  

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Serum samples from 20 Indian children with diarrhoea were compared with those from 20 children resident in the United Kingdom who had been diagnosed as having ulcerative colitis, or Crohn's disease, or indeterminate colitis using enzyme linked immunosorbent assays specific for Entamoeba histolytica and Giardia lamblia. More than 50% of the United Kingdom patients had high IgG responses in ELISAs for E histolytica and G lamblia. A confirmatory ELISA showed that the British sera reacted specifi...

1990-01-01

284

Identification in the Ancient Protist Giardia lamblia of Two Eukaryotic Translation Initiation Factor 4E Homologues with Distinctive Functions†  

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Eukaryotic translation initiation factor 4E (eIF4E) binds to the m7GTP of capped mRNAs and is an essential component of the translational machinery that recruits the 40S small ribosomal subunit. We describe here the identification and characterization of two eIF4E homologues in an ancient protist, Giardia lamblia. Using m7GTP-Sepharose affinity column chromatography, a specific binding protein was isolated and identified as Giardia eIF4E2. The other homologue, Giardia eIF4E1, bound only to the m2,2,7GpppN structure. Although neither homologue can rescue the function of yeast eIF4E, a knockdown of eIF4E2 mRNA in Giardia by a virus-based antisense ribozyme decreased translation, which was shown to use m7GpppN-capped mRNA as a template. Thus, eIF4E2 is likely the cap-binding protein in a translation initiation complex. The same knockdown approach indicated that eIF4E1 is not required for translation in Giardia. Immunofluorescence assays showed wide distribution of both homologues in the cytoplasm. But eIF4E1 was also found concentrated and colocalized with the m2,2,7GpppN cap, 16S-like rRNA, and fibrillarin in the nucleolus-like structure in the nucleus. eIF4E1 depletion from Giardia did not affect mRNA splicing, but the protein was bound to Giardia small nuclear RNAs D and H known to have an m2,2,7GpppN cap, thus suggesting a novel function not yet observed among other eIF4Es in eukaryotes.

Li, Lei; Wang, Ching C.

2005-01-01

285

Identification in the ancient protist Giardia lamblia of two eukaryotic translation initiation factor 4E homologues with distinctive functions.  

Science.gov (United States)

Eukaryotic translation initiation factor 4E (eIF4E) binds to the m(7)GTP of capped mRNAs and is an essential component of the translational machinery that recruits the 40S small ribosomal subunit. We describe here the identification and characterization of two eIF4E homologues in an ancient protist, Giardia lamblia. Using m(7)GTP-Sepharose affinity column chromatography, a specific binding protein was isolated and identified as Giardia eIF4E2. The other homologue, Giardia eIF4E1, bound only to the m(2,2,7)GpppN structure. Although neither homologue can rescue the function of yeast eIF4E, a knockdown of eIF4E2 mRNA in Giardia by a virus-based antisense ribozyme decreased translation, which was shown to use m(7)GpppN-capped mRNA as a template. Thus, eIF4E2 is likely the cap-binding protein in a translation initiation complex. The same knockdown approach indicated that eIF4E1 is not required for translation in Giardia. Immunofluorescence assays showed wide distribution of both homologues in the cytoplasm. But eIF4E1 was also found concentrated and colocalized with the m(2,2,7)GpppN cap, 16S-like rRNA, and fibrillarin in the nucleolus-like structure in the nucleus. eIF4E1 depletion from Giardia did not affect mRNA splicing, but the protein was bound to Giardia small nuclear RNAs D and H known to have an m(2,2,7)GpppN cap, thus suggesting a novel function not yet observed among other eIF4Es in eukaryotes. PMID:15879529

Li, Lei; Wang, Ching C

2005-05-01

286

Method to enumerate oocysts of cryptosporidium and cysts of Giardia in water  

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Cryptosporidium and Giardia have been recognized as etiological agents of gastrointestinal illness in humans with severe consequences on children and immunocompromised individuals. Water seems to be vehicle of infection. In last years many efforts have been done to evaluate a method to enumerate oocysts of Cryptosporidium and cysts of Giardia in waters. Throughout filtration and concentration steps, the two procedures proposed allow to enumerate oocysts and cysts belonging to the two genera of protozoa

2000-02-01

287

Prevalence of Giardia lamblia with or without diarrhea in South East, South East Asia and the Far East.  

Science.gov (United States)

This article is a review of the latest information on the prevalence of G. lamblia in South Asia, South East Asia and Far East, characterizing the current endemic situation within these regions. Around 33 published papers from 2002-2007 were collected on G. lamblia. The included countries were Nepal, Bangladesh, India, Cambodia, Vietnam, Malaysia, Philippines, Indonesia, Thailand, Republic of Korea, and China. Only five published papers were discarded because data was extracted before 2002-2007 or they are not included within our regions, emphasizing more on G. lamblia in animals, or performed at extensive molecular level. The prevalence of G. lamblia varied markedly between studies illustrating higher levels in the urban than in the rural areas, more among poor communities, slightly higher in males than in females with age range of 2-5-year-old children, and among university students, old-aged people, HIV-positive patients, and gastric carcinoma patients. Though G. lamblia is not a life-threatening parasite, nevertheless, it is still considered as the most common water-borne diarrhea-causing disease. It is important to understand the etiology, frequency, and consequences of acute diarrhea in children. Routine surveillance such as bi-annual follow-up treatments, treating G. duodenalis cysts and other protozoa oocysts detected in ground water sources, and continuous health education are the most preventive measures. PMID:18425689

Dib, Hassan H; Lu, Si Qi; Wen, Shao Fang

2008-07-01

288

Variant surface antigens of Giardia lamblia are associated with the presence of a thick cell coat: thin section and label fracture immunocytochemistry survey.  

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Giardia lamblia undergoes surface antigenic variation. The ultrastructural location of antigens on four different variants was studied by label fracture and immunocytochemistry with four monoclonal antibodies (MAbs), each of which recognized the predominant variant in a particular clone. Each Giardia clone and its reacting MAb showed similar findings. The entire surface of the organism was covered by a surface coat which contained the variant surface protein. The surface coat was densely and ...

Pimenta, P. F.; Da Silva, P. P.; Nash, T.

1991-01-01

289

Adaptor Protein Complex 1 Mediates the Transport of Lysosomal Proteins from a Golgi-like Organelle to Peripheral Vacuoles in the Primitive Eukaryote Giardia lamblia  

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Giardia lamblia is an early branching protist that possesses peripheral vacuoles (PVs) with characteristics of lysosome-like organelles, located underneath the plasma membrane. In more evolved cells, lysosomal protein trafficking is achieved by cargo recognition involving adaptor protein (AP) complexes that recognize specific amino acid sequences (tyrosine and/or dileucine motifs) within the cytoplasmic tail of membrane proteins. Previously, we reported that Giardia has a tyrosine-based sorti...

Touz, Mari?a C.; Kulakova, Liudmila; Nash, Theodore E.

2004-01-01

290

Commercial Assay for Detection of Giardia lamblia and Cryptosporidium parvum Antigens in Human Fecal Specimens by Rapid Solid-Phase Qualitative Immunochromatography  

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The ImmunoCard STAT! Cryptosporidium/Giardia rapid assay (Meridian Bioscience, Inc.) is a solid-phase qualitative immunochromatographic assay that detects and distinguishes between Giardia lamblia and Cryptosporidium parvum in aqueous extracts of human fecal specimens (fresh, frozen, unfixed, or fixed in 5 or 10% formalin or sodium acetate-acetic acid-formalin). By using specific antibodies, antigens specific for these organisms are isolated and immobilized on a substrate. After the addition ...

Garcia, Lynne S.; Shimizu, Robyn Y.; Novak, Susan; Carroll, Marilyn; Chan, Frank

2003-01-01

291

Crystal structure of a macrophage migration inhibitory factor from Giardia lamblia  

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Macrophage migration inhibitory factor (MIF) is a eukaryotic cytokine that affects a broad spectrum of immune responses and its activation/inactivation is associated with numerous diseases. During protozoan infections MIF is not only expressed by the host, but, has also been observed to be expressed by some parasites and released into the host. To better understand the biological role of parasitic MIF proteins, the crystal structure of the MIF protein from Giardia lamblia (Gl-MIF), the etiological agent responsible for giardiasis, has been determined at 2.30 Å resolution. The 114-residue protein adopts an ?/? fold consisting of a four-stranded ?-sheet with two anti-parallel ?-helices packed against a face of the ?-sheet. An additional short ?-strand aligns anti-parallel to ?4 of the ?-sheet in the adjacent protein unit to help stabilize a trimer, the biologically relevant unit observed in all solved MIF crystal structures to date, and form a discontinuous ?-barrel. The structure of Gl-MIF is compared to the MIF structures from humans (Hs-MIF) and three Plasmodium species (falciparum, berghei, and yoelii). The structure of all five MIF proteins are generally similar with the exception of a channel that runs through the center of each trimer complex. Relative to Hs-MIF, there are differences in solvent accessibility and electrostatic potential distribution in the channel of Gl-MIF and the Plasmodium-MIFs due primarily to two “gate-keeper” residues in the parasitic MIFs. For the Plasmodium MIFs the gate-keeper residues are at positions 44 (Y==>R) and 100 (V==>D) and for Gl-MIF it is at position 100 (V==>R). If these gate-keeper residues have a biological function and contribute to the progression of parasitemia they may also form the basis for structure-based drug design targeting parasitic MIF proteins.

Buchko, Garry W.; Abendroth, Jan; Robinson, Howard; Zhang, Yanfeng; Hewitt, Stephen N.; Edwards, Tom E.; Van Voorhis, Wesley C.; Myler, Peter J.

2013-06-15

292

COMPARISON OF ANIMAL INFECTIVITY AND EXCYSTATION AS MEASURES OF 'GIARDIA MURIS' CYST INACTIVATION BY CHLORINE  

Science.gov (United States)

In the study, in vitro excystation and mouse infectivity were compared as methods for quantitatively determining the viability of Giardia muris cysts before and after exposure to free residual chlorine. The mouse infectivity results show that very few cysts (1-15) constitute an i...

293

EVALUATING SEDIMENTATION AND VARIOUS FILTER MEDIA FOR REMOVAL OF 'GIARDIA' CYSTS  

Science.gov (United States)

The primary purpose of the pilot study described in this article was to evaluate the efficiency of sedimentation and of coarse anthracite media for removing Giardia cysts. Removal of cysts by sedimentation was observed to range from 65 to 93 percent and was generally similar to r...

294

Identification and analysis of the RNA degrading complexes and machinery of Giardia lamblia using an in silico approach  

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Full Text Available Abstract Background RNA degradation is critical to the survival of all cells. With increasing evidence for pervasive transcription in cells, RNA degradation has gained recognition as a means of regulating gene expression. Yet, RNA degradation machinery has been studied extensively in only a few eukaryotic organisms, including Saccharomyces cerevisiae and humans. Giardia lamblia is a parasitic protist with unusual genomic traits: it is binucleated and tetraploid, has a very compact genome, displays a theme of genomic minimalism with cellular machinery commonly comprised of a reduced number of protein components, and has a remarkably large population of long, stable, noncoding, antisense RNAs. Results Here we use in silico approaches to investigate the major RNA degradation machinery in Giardia lamblia and compare it to a broad array of other parasitic protists. We have found key constituents of the deadenylation and decapping machinery and of the 5'-3' RNA degradation pathway. We have similarly found that all of the major 3'-5' RNA degradation pathways are present in Giardia, including both exosome-dependent and exosome-independent machinery. However, we observe significant loss of RNA degradation machinery genes that will result in important differences in the protein composition, and potentially functionality, of the various RNA degradation pathways. This is most apparent in the exosome, the central mediator of 3'-5' degradation, which apparently contains an altered core configuration in both Giardia and Plasmodium, with only four, instead of the canonical six, distinct subunits. Additionally the exosome in Giardia is missing both the Rrp6, Nab3, and Nrd1 proteins, known to be key regulators of noncoding transcript stability in other cells. Conclusions These findings suggest that although the full complement of the major RNA degradation mechanisms were present - and likely functional - early in eukaryotic evolution, the composition and function of the complexes is more variable than previously appreciated. We suggest that the missing components of the exosome complex provide an explanation for the stable abundance of sterile RNA species in Giardia.

Williams Christopher W

2011-11-01

295

Detection of Giardia lamblia and Cryptosporidium parvum Antigens in Human Fecal Specimens Using the ColorPAC Combination Rapid Solid-Phase Qualitative Immunochromatographic Assay  

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The ColorPAC Giardia/Cryptosporidium (Becton Dickinson) is a solid-phase qualitative immunochromatographic assay that detects and distinguishes between Giardia lamblia and Cryptosporidium parvum in human stool. Agreement between the Alexon-Trend ProSpecT Giardia Rapid EIA and the ColorPAC assay was 166 of 172 (96.5%). Agreement between the Alexon-Trend ProSpecT Cryptosporidium Rapid EIA and the ColorPAC assay was 169 of 171 (98.8%). No cross-reactions were seen with other parasites or human c...

Garcia, Lynne S.; Shimizu, Robyn Y.

2000-01-01

296

Virtual screening of combinatorial libraries across a gene family: in search of inhibitors of Giardia lamblia guanine phosphoribosyltransferase.  

Science.gov (United States)

Parasitic protozoa lack the ability to synthesize purine nucleotides de novo, relying instead on purine salvage enzymes for their survival. Guanine phosphoribosyltransferase (GPRT) from the protozoan parasite Giardia lamblia is a potential target for rational antiparasitic drug design, based on the experimental evidence, which indicates the lack of interconversion between adenine and guanine nucleotide pools. The present study is a continuation of our efforts to use three-dimensional structures of parasitic phosphoribosyltransferases (PRTs) to design novel antiparasitic agents. Two micromolar phthalimide-based GPRT inhibitors were identified by screening the in-house phthalimide library. A combination of structure-based scaffold selection using virtual library screening across the PRT gene family and solid phase library synthesis led to identification of smaller (molecular weight, <300) ligands with moderate to low specificity for GPRT; the best inhibitors, GP3 and GP5, had K(i) values in the 23 to 25 microM range. These results represent significant progress toward the goal of designing potent inhibitors of purine salvage in Giardia parasites. As a second step in this process, altering the phthalimide moiety to optimize interactions in the guanine-binding pocket of GPRT is expected to lead to compounds with promising activity against G. lamblia PRT. PMID:11502531

Aronov, A M; Munagala, N R; Kuntz, I D; Wang, C C

2001-09-01

297

Growth inhibition of the intestinal parasite Giardia lamblia by a dietary lectin is associated with arrest of the cell cycle.  

Science.gov (United States)

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. PMID:7989583

Ortega-Barria, E; Ward, H D; Keusch, G T; Pereira, M E

1994-12-01

298

The principal conductance in Giardia lamblia trophozoites possesses functional properties similar to the mammalian ClC-2 current.  

Science.gov (United States)

The human intestinal pathogen Giardia lamblia is a flagellated unicellular protozoan with pronounced medical and biological relevance. However, the basic physiology of Giardia trophozoites has been sparsely studied, especially the electrical and ionic properties of their cellular membrane which are virtually unknown. In this study, we were able to record and characterize the macroscopic ionic currents of Giardia trophozoite membrane by electrophysiological methods of the patch clamp technique. Giardia trophozoites showed a high current density (?600 pA/pF at -140 mV) that was activated upon hyperpolarization. This current was carried by a chloride-selective channel (I Cl-G) and it was the most important determinant of the membrane potential in Giardia trophozoites. Moreover, this conductance was able to carry other halide anions and the sequence of permeability was Br(-)?>?Cl(-)???I(-)???F(-). Besides the voltage-dependent inward-rectifying nature of I Cl-G, its activation and deactivation kinetics were comparable to those observed in ClC-2 channels. Extracellular pH modified the voltage-dependent properties of I Cl-G, shifting the activation curve from a V 1/2?=?-79?±?1 mV (pH 7.4) to -93?±?2 mV (pH 8.4) and -112?±?2 mV (pH 5.4). Furthermore, the maximal amplitude of I Cl-G measured at -100 mV showed dependence to external pH in a bell-shaped fashion reported only for ClC-2 channels. Therefore, our results suggest that I Cl-G possesses several functional properties similar to the mammalian ClC-2 channels. PMID:24043571

Moreno-Galindo, Eloy G; Rodríguez-Elías, Julio C; Ramírez-Herrera, Mario A; Sánchez-Chapula, José A; Navarro-Polanco, Ricardo A

2014-05-01

299

Comparison of animal infectivity and excystation as measures of Giardia muris cyst inactivation by chlorine.  

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In this study, in vitro excystation and mouse infectivity were compared as methods for quantitatively determining the viability of Giardia muris cysts before and after exposure to free residual chlorine. The mouse infectivity results show that very few cysts (1 to 15) constitute an infectious dose. The results of the inactivation studies indicate that in vitro excystation is an adequate indication of G. muris cyst infectivity for the host and can be used to determine the effects of disinfecta...

Hoff, J. C.; Rice, E. W.; Schaefer, F. W.

1985-01-01

300

X-ray structure and characterization of carbamate kinase from the human parasite Giardia lamblia  

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The three-dimensional structure of carbamate kinase from the human parasite G. lamblia has been determined at 3?Å resolution. Steady-state kinetic parameters have been determined and dsRNA-silencing experiments indicate that the enzyme is essential for the survival of G. lamblia.

Galkin, Andrey; Kulakova, Liudmila; Wu, Rui; Nash, Theodore E.; Dunaway-mariano, Debra; Herzberg, Osnat

2010-01-01

 
 
 
 
301

Dual acylation accounts for the localization of {alpha}19-giardin in the ventral flagellum pair of Giardia lamblia.  

Science.gov (United States)

A Giardia-specific protein family denominated as alpha-giardins, represents the major protein component, besides tubulin, of the cytoskeleton of the human pathogenic parasite Giardia lamblia. One of its members, alpha19-giardin, carries an N-terminal sequence extension of MGCXXS, which in many proteins serves as a target for dual lipid conjugation: myristoylation at the glycine residue after removal of the methionine and palmitoylation at the cysteine residue. As the first experimental evidence of a lipid modification, we found alpha19-giardin to be associated with the membrane fraction of disrupted trophozoites. After heterologous coexpression of alpha19-giardin with giardial N-myristoyltransferase (NMT) in Escherichia coli, we found the protein in a myristoylated form. Additionally, after heterologous expression together with the palmitoyl transferase Pfa3 in Saccharomyces cerevisiae, alpha19-giardin associates with the membrane of the main vacuole. Immunocytochemical colocalization studies on wild-type Giardia trophozoites with tubulin provide evidence that alpha19-giardin exclusively localizes to the ventral pair of the giardial flagella. A mutant in which the putatively myristoylated N-terminal glycine residue was replaced by alanine lost this specific localization. Our findings suggest that the dual lipidation of alpha19-giardin is responsible for its specific flagellar localization. PMID:19684283

Saric, Mirela; Vahrmann, Anke; Niebur, Daniela; Kluempers, Verena; Hehl, Adrian B; Scholze, Henning

2009-10-01

302

SUMOylation in Giardia lamblia: A Conserved Post-Translational Modification in One of the Earliest Divergent Eukaryotes  

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Full Text Available Post-translational modifications are able to regulate protein function and cellular processes in a rapid and reversible way. SUMOylation, the post-translational modification of proteins by the addition of SUMO, is a highly conserved process that seems to be present in modern cells. However, the mechanism of protein SUMOylation in earlier divergent eukaryotes, such as Giardia lamblia, is only starting to become apparent. In this work, we report the presence of a single SUMO gene encoding to SUMO protein in Giardia. Monoclonal antibodies against recombinant Giardia SUMO protein revealed the cytoplasmic localization of native SUMO in wild-type trophozoites. Moreover, the over-expression of SUMO protein showed a mainly cytoplasmic localization, though also neighboring the plasma membrane, flagella, and around and even inside the nuclei. Western blot assays revealed a number of SUMOylated proteins in a range between 20 and 120 kDa. The genes corresponding to putative enzymes involved in the SUMOylation pathway were also explored. Our results as a whole suggest that SUMOylation is a process conserved in the eukaryotic lineage, and that its study is significant for understanding the biology of this interesting parasite and the role of post-translational modification in its evolution.

Andrea S. Rópolo

2012-07-01

303

The profile of snoRNA-derived microRNAs that regulate expression of variant surface proteins in Giardia lamblia.  

Science.gov (United States)

In the current investigation, we analysed all the known small nucleolar RNAs (snoRNAs) in the deeply branching protozoan parasite Giardia lamblia for potential microRNAs (miRNAs) that might be derived from them. Two putative miRNAs have since been identified by Northern blot, primer extension, 3' RACE and co-immunoprecipitation with Giardia Argonaute (GlAgo), and designated miR6 and miR10. Giardia Dicer (GlDcr) is capable of processing the snoRNAs into the corresponding miRNAs in vitro. Potential miR6 and miR10 binding sites in Giardia genome were predicted bio-informatically. A miR6 binding site was found at the 3' untranslated regions (UTR) of 44 variant surface protein (vsp) genes, whereas a miR10 binding site was identified at the 3' end of 159 vsp open-reading frames. Thirty-three of these vsp genes turned out to contain binding sites for both miR6 and miR10. A reporter mRNA tagged with the 3' end of vsp1267, which contains the target sites for both miRNAs, was translationally repressed by both miRNAs in Giardia. Episomal expression of an N-terminal c-myc tagged VSP1267 was found significantly repressed by introducing either miR6 or miR10 into the cells and the repressive effects were additive. When the 2'-O-methyl antisense oligos (ASOs) of either miR6 or miR10 was introduced, however, there was an enhancement of tagged VSP1267 expression suggesting an inhibition of the repressive effects of endogenous miR6 or miR10 by the ASOs. Of the total 220 vsp genes in Giardia, we have now found 178 of them carrying putative binding sites for all the miRNAs that have been currently identified, suggesting that miRNAs are likely the regulators of VSP expression in Giardia. PMID:22568619

Li, Wei; Saraiya, Ashesh A; Wang, Ching C

2012-09-01

304

Occurrence of Cryptosporidium Oocysts and Giardia Cysts in Sewage in Norway†  

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Samples of sewage influent from 40 sewage treatment works (STW) throughout Norway were examined for Cryptosporidium oocysts and Giardia duodenalis cysts. Both parasites were detected frequently (80% of STW were Cryptosporidium positive; 93% of STW were Giardia positive) and at maximum concentrations of >20,000 parasites/liter. The data suggest giardiasis is more widespread, and/or occurs with greater infection intensity, than cryptosporidiosis in Norway. STW serving higher person equivalents ...

Robertson, L. J.; Hermansen, L.; Gjerde, B. K.

2006-01-01

305

Existence of Cryptosporidium spp. oocysts and Giardia spp. cysts in well water in Nineveh governorate  

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Full Text Available The study included examination of 110 water samples from well distributed in Mosul city and few towns and villages around it from May 2009 to March 2010 for detection of Cryptosporidium spp oocysts and Giardia spp cysts in well water. The results revealed that the prevalence of Cryptosporidium oocysts was 16.36% while the prevalence of Giardia cysts was 12.72%. The percentages of prevalence with Cryptosporidium and Giardia were in high rate in Bartilla and some villages around it 20% for Cryptosporidium and 17.14% for Giardia, the low rates were in Mosul city 10% for both protozoa. The highest prevalence rate of Cryptosporidium was in March 38.46% and the lowest was in November and July 0%. The highest prevalence rate of Giardia was in October 23.53% and the lowest rate in July 0%. This first study shows the presence of Cryptosporidium oocysts and Giardia cysts in well water (Ground water in Nineveh governorate.

R. G. Mohammad

2011-01-01

306

Occurrence of Cryptosporidium oocysts and Giardia cysts in water supplies of San Pedro Sula, Honduras  

Scientific Electronic Library Online (English)

Full Text Available SciELO Public Health | Language: English Abstract in spanish Para estimar las concentraciones de oocistos de Cryptosporidium y quistes de Giardia en los abastecimientos de agua de la ciudad de San Pedro Sula, se examinaron muestras del agua en junio de 1996. Cada muestra se concentró y se marcó con un anticuerpo inmunofluorescente indirecto y los parásitos se [...] contaron mediante análisis microscópico. En tres abatecimientos de agua, las concentraciones de oocistos de Cryptosporidium alcanzaron un recorrido de 58 a 260 oocistos por 100 L, mientras que los quistes de Giardia se encontraron en concentraciones de 380 a 2100 quistes por 100 L. Al contrario de las muestras de agua superficial, el agua subterránea tuvo mayor concentración de oocistos de Cryptosporidium (26/100 L) que de quistes de Giardia (6/100 L), lo que sugiere que el acuífero subterráneo protege mejor al abastecimiento de agua contra los quistes de Giardia, que son más grandes. Las concentraciones de oocistos de Cryptosporidium estuvieron dentro del recorrido típico de los abastecimientos de agua en Norteamérica, pero los de Giardia fueron más elevados. Deben tomarse medidas para proteger el agua sin depurar de las fuentes de contaminación. Abstract in english During June 1996, water supplies of the city of San Pedro Sula, Honduras, were sampled to obtain an assessment of Cryptosporidium oocyst and Giardia cyst concentrations. Each sample was concentrated and stained with an indirect immunofluorescent antibody, and parasites were counted through microscop [...] ic analysis. In three surface water supplies, Cryptosporidium oocyst concentrations ranged from 58 to 260 oocysts per 100 L, and Giardia cysts were present in concentrations ranging from 380 to 2100 cysts per 100 L. Unlike the surface water samples, groundwater had a higher concentration of Cryptosporidium oocysts (26/100 L) than Giardia cysts (6/100 L), suggesting that the groundwater aquifer protects the water supply more effectively from larger Giardia cysts. Cryptosporidium oocyst concentrations are within the typical range for surface water supplies in North America whereas Giardia cyst concentrations are elevated. Efforts should be made to protect raw water from sources of contamination.

Solo-Gabriele, Helena María; Ager, Jr., Arba LeRoy; Lindo, John Fitzgerald; Dubón, José María; Neumeister, Shondra Michelle; Baum, Marianna Karas; Palmer, Carol Jean.

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Expression, purification, crystallization and preliminary X-ray diffraction analysis of alpha-11 giardin from Giardia lamblia.  

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Alpha-11 Giardin, a protein from the annexin superfamily, is a 35.0 kDa protein from the intestinal protozoan parasite Giardia lamblia which triggers a form of diarrhea called giardiasis. Here, the cloning, expression, purification and the crystallization of alpha-11 giardin under two different conditions and in two different space groups is reported. Crystals from the first condition diffracted to 1.1 A and belong to a primitive orthorhombic space group, while crystals from the second condition, which included calcium in the crystallization solution, diffracted to 2.93 A and belong to a primitive monoclinic space group. Determination of the detailed atomic structure of alpha-11 giardin will provide a better insight into its biological function and might establish whether this class of proteins is a potential drug target against giardiasis. PMID:17077490

Pathuri, Puja; Nguyen, Emily Tam; Luecke, Hartmut

2006-11-01

308

Characteristics and risk factors for symptomatic Giardia lamblia infections in Germany  

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Abstract Background In developed countries, giardiasis is considered a travel related disease. However, routine surveillance data from Germany indicate that >50% of infections were acquired indigenously. We studied the epidemiological characteristics of symptomatic Giardia infections acquired in Germany and abroad, and verified the proportion of cases acquired in Germany in order to investigate risk factors for sporadic autochthonous Giardia infections. ...

Espelage Werner; an der Heiden Matthias; Stark Klaus; Alpers Katharina

2010-01-01

309

Numerous fragmented spliceosomal introns, AT-AC splicing, and an unusual dynein gene expression pathway in Giardia lamblia.  

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Spliceosomal introns are hallmarks of eukaryotic genomes, dividing coding regions into separate exons, which are joined during mRNA intron removal catalyzed by the spliceosome. With few known exceptions, spliceosomal introns are cis-spliced, that is, removed from one contiguous pre-mRNA transcript. The protistan intestinal parasite Giardia lamblia exhibits one of the most reduced eukaryotic genomes known, with short intergenic regions and only four known spliceosomal introns. Our genome-wide search for additional introns revealed four unusual cases of spliceosomal intron fragmentation, with consecutive exons of conserved protein-coding genes being dispersed to distant genomic sites. Independent transcripts are trans-spliced to yield contiguous mature mRNAs. Most strikingly, a dynein heavy chain subunit is both interrupted by two fragmented introns and also predicted to be assembled as two separately translated polypeptides, a remarkably complex expression pathway for a nuclear-encoded sequence. For each case, we observe extensive base-pairing potential between intron halves. This base pairing provides both a rationale for the in vivo association of independently transcribed mRNAs transcripts and the apparent specificity of splicing. Similar base-pairing potential in two cis-spliced G. lamblia introns suggests an evolutionary pathway whereby intron fragmentation of cis-spliced introns is permissible and a preliminary evolutionary step to complete gene fission. These results reveal remarkably complex genome dynamics in a severely genomically reduced parasite. PMID:21482665

Roy, Scott W; Hudson, Andrew J; Joseph, Joella; Yee, Janet; Russell, Anthony G

2012-01-01

310

Occurence of Giardia lamblia in children of municipal day-care centers from Botucatu, São Paulo State, Brazil Ocorrência de Giardia lamblia em crianças atendidas em creches municipais de Botucatu, Estado de São Paulo, Brasil  

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Full Text Available Considering that the number of day-care centers for pre-school-age children has expanded rapidly in developing countries, and that these institutions presenting conditions that facilitate the transmission of many enteric agents, a parasitological survey was carried out in three municipal day-cares from Botucatu: two in the urban area (one in downtown area and the other one in the city periphery area and the third in the rural area. Three separate stool specimens were collected from 147 children ranging from 0 to 72 months old and 20 staff members. Each stool specimen was processed by Lutz and zinc sulfate flotation methods. The frequency of giardiasis observed among children of downtown, periphery and rural day-cares was 69.6%, 52.7% and 69.6%, respectively. Only one employee was positive for G. lamblia. The examination of three stool specimens increased the positivity for G. lamblia: from the ninety three final positive examinations, 24 (25.5% and 8 (8.5% were positives only after examination of the second and third samples, respectively. Others intestinal organisms like Ascaris lumbricoides (20.4%, Trichuris trichiura (19.0%. Hymenolepis nana (8.8%, Entamoeba coli (22.4% and Blastocystis hominis (32.0% were frequently found in the children. There was no significant association among localization of the day-cares, sex of the children and the levels of G. lamblia infection. According to the age, G. lamblia was found mainly in children between 12 to 47 months old.Foi realizado um levantamento parasitológico em três creches da rede municipal: duas na área urbana, uma no centro da cidade e a outra na periferia, e a terceira na zona rural. Três amostras de fezes, coletadas com intervalo de 7 dias, foram obtidas de 147 crianças com idade variando de 0 a 6 anos e de 20 funcionários. Cada amostra foi processada pelos métodos de sedimentação espontânea e centrífugo - flutuação com sulfato de zinco. Os resultados demonstraram que das 147 crianças examinadas, 93 (63,3% apresentaram cistos de G. lamblia nas fezes. Apenas 1 funcionário foi positivo para G. lamblia. O uso de 3 amostras de fezes aumentou a positividade do exame para o diagnóstico deste parasita, uma vez que dos 93 casos positivos, 24 (25,5% e 8 (8,5% foram diagnosticados somente após exame da segunda e terceira amostras, respectivamente. Outros parasitas e comensais intestinais como Ascaris lumbricoides (20,4%, Trichuris trichiura (19,0%, Hymenolepis nana (8,8%, Entamoeba coli (22,4% e Blastocystis hominis (32,0% foram diagnosticados. A análise estatística revelou não haver associação entre localização das creches, sexo e a frequência de infecção por G. lamblia. As porcentagens mais altas de infecção por Giardia foram observadas entre as crianças com idade variando de 1 a 4 anos.

Semíramis Guimarães

1995-12-01

311

Influence of Antibodies in Mother’s Milk on Antigenic Variation of Giardia lamblia in the Murine Mother-Offspring Model of Infection  

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In the present study, neonatal ZU.ICR mice and their mothers were infected with trophozoites of Giardia lamblia clone GS/M-83-H7 expressing the variant surface protein (VSP) H7. The infection experiments included a detailed analysis of the specificities of anti-Giardia immunoglobulin A (IgA) antibodies in mother’s milk and a determination of the effects of the milk antibodies on both the growth of the parasite during in vitro cultivation and colonization of the parasite within the intestine...

Sta?ger, S.; Gottstein, B.; Sager, H.; Jungi, T. W.; Mu?ller, N.

1998-01-01

312

Identification of scaffold/Matrix Attachment (S/MAR like DNA element from the gastrointestinal protozoan parasite Giardia lamblia  

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Full Text Available Abstract Background Chromatin in the nucleus of all eukaryotes is organized into a system of loops and domains. These loops remain fastened at their bases to the fundamental framework of the nucleus, the matrix or the scaffold. The DNA sequences which anchor the bases of the chromatin loops to the matrix are known as Scaffold/Matrix Attachment Regions or S/MARs. Though S/MARs have been studied in yeast and higher eukaryotes and they have been found to be associated with gene organization and regulation of gene expression, they have not been reported in protists like Giardia. Several tools have been discovered and formulated to predict S/MARs from a genome of a higher eukaryote which take into account a number of features. However, the lack of a definitive consensus sequence in S/MARs and the randomness of the protozoan genome in general, make it a challenge to predict and identify such sequences from protists. Results Here, we have analysed the Giardia genome for the probable S/MARs predicted by the available computational tools; and then shown these sequences to be physically associated with the nuclear matrix. Our study also reflects that while no single computational tool is competent to predict such complex elements from protist genomes, a combination of tools followed by experimental verification is the only way to confirm the presence of these elements from these organisms. Conclusion This is the first report of S/MAR elements from the protozoan parasite Giardia lamblia. This initial work is expected to lay a framework for future studies relating to genome organization as well as gene regulatory elements in this parasite.

Gautam Pennathur

2010-06-01

313

Giardia y giardiasis Giardia and giardiasis  

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Full Text Available Giardia lamblia es un protozoario parásito que habita el intestino delgado de los seres humanos y de muchos otros vertebrados y es una de las más comunes causas de diarrea en todo el mundo. Durante su ciclo de vida Giardia sufre significativos cambios bioquímicos y morfológicos que le permiten sobrevivir en ambientes y condiciones que de otro modo lo destruirían. Para sobrevivir fuera del intestino del hospedador, los trofozoítos de Giardia se diferencian a quistes, los que se caracterizan por poseer una rígida pared glicoproteica externa que les permiten sobrevivir inclusive frente a la acción de los desinfectantes más comunes. Otro de los mecanismos de adaptación de este parásito es la variación de los antígenos de superficie que le permite a los trofozoítos evadir la respuesta inmune del huésped y generar infecciones tanto agudas como crónicas o recurrentes en individuos infectados. Durante los últimos años se han producido importantes avances en el conocimiento de las bases moleculares de los procesos de enquistamiento y variación antigénica en Giardia que pronostican el pronto hallazgo de nuevos agentes quimioterapéuticos y/o inmunoprofilácticos contra este importante parásito intestinal.Giardia lamblia is a protozoan parasite that inhabits the upper small intestine of humans and several other vertebrates and one of the most frequent cause of intestinal disease worldwide. During its life cycle, G. lamblia undergoes significant biochemical and morphological changes that allow the parasite to survive under hostile environmental conditions. To survive outside the host’s intestine, Giardia differentiates into resistant cysts, which are characterized by a rigid extracellular cyst wall that protect the parasite even to the action of the most common chemical disinfectants. Another adaptive mechanism of Giardia is the switching of its surface antigens, a mechanism that allows the trophozoites to evade the host’s immune responses and produce acute, chronic and/or recurrent infections. During the last years, important advances in the knowledge of the molecular basis underlying the mechanisms of encystation and antigenic variation in Giardia suggest that novel chemotherapeutic and/or immunoprophylactic reagents against this important human pathogen could soon be available.

Hugo D. Luján

2006-02-01

314

FILTRATION OF 'GIARDIA' CYSTS AND OTHER SUBSTANCES. VOLUME 2. SLOW SAND FILTRATION  

Science.gov (United States)

Slow sand filtration research was conducted at Colorado State University in two phases, using 1 foot diameter filters. Phase I results showed removal of Giardia cysts exceeded 99.9 percent for the three hydraulic loading rates used. The most important operating condition was the ...

315

Occurrence of Cryptosporidium oocysts and Giardia cysts in Norwegian groundwater wells in bedrock.  

Science.gov (United States)

The occurrence of Cryptosporidium oocysts and Giardia cysts in Norwegian groundwater wells in bedrock has been investigated for the first time. Wells close to risk areas such as farming and septic tanks were chosen. In all, 20 water samples from 20 different waterworks were collected. The samples were analysed for Cryptosporidium and Giardia, using US EPA Method 1623. Turbidity was also measured. Water samples from 10 of the waterworks were also analysed for Clostridium perfringens by membrane filtration. Cryptosporidium was detected in the groundwater samples from 3 of the waterworks. Giardia and Clostridium perfringens were not detected. Too few samples were analysed to verify whether Giardia is indeed absent from bedrock wells, and further studies are recommended to give more reliable data. PMID:19108559

Gaut, Sylvi; Robertson, Lucy; Gjerde, Bjørn; Dagestad, Atle; Brattli, Bjørge

2008-09-01

316

Prevalence and Spatial Distribution of Entamoeba histolytica/dispar and Giardia lamblia among Schoolchildren in Agboville Area (Côte d'Ivoire)  

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According to WHO, intestinal amoebiasis caused by Entamoeba histolytica is the third principal parasitic disease responsible for mortality in the world. This protozoal parasite infects approximately 180 million individuals throughout the world, among whom 40 to 110 thousand die from it each year. Giardiasis, caused by another protozoan parasite, Giardia lamblia, infects approximately 200 million individuals throughout the world, is a frequent cause of diarrhea in children, and can have negati...

Ouattara, Mamadou; N Gue?ssan, Nicaise A.; Yapi, Ahoua; N Goran, Elie?zer K.

2010-01-01

317

Effects of bile and bile salts on growth and membrane lipid uptake by Giardia lamblia. Possible implications for pathogenesis of intestinal disease.  

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We have shown previously that ox and pig bile accelerate in vitro growth of Giardia lamblia. We have now investigated the possible mechanisms by which mammalian biles promote parasite growth. Growth effects of (a) ox, pig, guinea pig, and human biles, (b) pure bile salts, and (c) egg and soybean lecithins were studied in the presence of a lecithin-containing growth medium. Individually, dilute native bile and pure sodium taurocholate (TC), glycocholate (GC), and taurodeoxycholate (TDC) promot...

Farthing, M. J.; Keusch, G. T.; Carey, M. C.

1985-01-01

318

Evaluation of the Triage Micro Parasite Panel for Detection of Giardia lamblia, Entamoeba histolytica/Entamoeba dispar, and Cryptosporidium parvum in Patient Stool Specimens  

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A study comparing the Triage Micro Parasite Panel (Biosite Diagnostics, Inc., San Diego, Calif.) to conventional O&P examination (O&P) was performed using patient fecal specimens. Five hundred twenty-three stool samples were compared. Nineteen specimens were found to be positive by Triage, and 29 were found to be positive by O&P. Seven specimens were positive for Giardia lamblia, four were positive for Entamoeba histolytica/E. dispar, and three were positive for Cryptosporidium parvum as dete...

Sharp, Susan E.; Suarez, Clarisa A.; Duran, Yolanda; Poppiti, Robert J.

2001-01-01

319

Detection of Giardia lamblia, Entamoeba histolytica/Entamoeba dispar, and Cryptosporidium parvum Antigens in Human Fecal Specimens Using the Triage Parasite Panel Enzyme Immunoassay  

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The Triage parasite panel (BIOSITE Diagnostics, San Diego, Calif.) is a new qualitative enzyme immunoassay (EIA) panel for the detection of Giardia lamblia, Entamoeba histolytica/E. dispar, and Cryptosporidium parvum in fresh or fresh, frozen, unfixed human fecal specimens. By using specific antibodies, antigens specific for these organisms are captured and immobilized on a membrane. Panel performance was evaluated with known positive and negative stool specimens (a total of 444 specimens) th...

Garcia, Lynne S.; Shimizu, Robyn Y.; Bernard, Caroline N.

2000-01-01

320

Evaluation of nine immunoassay kits (enzyme immunoassay and direct fluorescence) for detection of Giardia lamblia and Cryptosporidium parvum in human fecal specimens.  

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It is well known that Giardia lamblia and Cryptosporidium parvum can cause severe symptoms in humans, particularly those who are immunologically compromised. Immunoassay procedures offer both increased sensitivity and specificity compared to conventional staining methods. These reagents are also helpful when screening large numbers of patients, particularly in an outbreak situation or when screening patients with minimal symptoms. The data obtained by using 9 diagnostic kits were compared: di...

Garcia, L. S.; Shimizu, R. Y.

1997-01-01

 
 
 
 
321

Guanine nucleotide-binding proteins in the intestinal parasite Giardia lamblia. Isolation of a gene encoding an approximately 20-kDa ADP-ribosylation factor.  

Science.gov (United States)

Giardia lamblia is a protozoan intestinal parasite that has characteristics of both eukaryotes and prokaryotes. To determine whether genes for guanine nucleotide-binding proteins are present in Giardia, genomic DNA and cDNA libraries were screened by polymerase chain reaction and by hybridization with mixed oligonucleotide probes complementary to sequences encoding conserved GTP-binding domains. A gene with a high degree of sequence identity with mammalian ADP-ribosylation factors (ARFs), believed to be important in vesicular transport, was identified. The Giardia ARF gene had a 573-base open reading frame encoding 191 amino acids which are 63-70% identical with known mammalian and yeast ARFs. Sequence conservation among ARFs was greatest in putative GTP-binding domains. A single ARF mRNA species of approximately 750 bases was found in two different Giardia isolates. Primer extension and RNA sequencing of the Giardia ARF transcript revealed a short (6-base) 5'-untranslated region similar in size to those found in other Giardia transcripts. Giardia extracts contained ARF activity, as shown by stimulation of cholera toxin-catalyzed ADP-ribosylation and a Giardia ARF expressed in Escherichia coli as a fusion protein likewise exhibited biochemical activity. Its presence in Giardia is consistent with the view that ARF emerged before the divergence of this protozoan from other eukaryotes (approximately 1.5 billion years ago), and that an ARF-like protein may have been the ancestor of several other classes of signal-transducing guanine nucleotide-binding proteins, including the alpha subunits of the heterotrimeric G proteins. PMID:1577802

Murtagh, J J; Mowatt, M R; Lee, C M; Lee, F J; Mishima, K; Nash, T E; Moss, J; Vaughan, M

1992-05-15

322

Expression, purification, crystallization and preliminary X-ray diffraction analysis of ?-11 giardin from Giardia lamblia  

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?-11 giardin from the intestinal protozoan parasite, G. lamblia has been cloned, expressed, purified and crystallized under two different conditions and in two different space groups. Crystals from the first condition diffracted to 1.1?Å and belong to a primitive orthorhombic space group and crystals obtained in the second condition diffracted to 2.93?Å and belong to a primitive monoclinic space group.

Pathuri, Puja; Nguyen, Emily Tam; Luecke, Hartmut

2006-01-01

323

Identification of Obscure yet Conserved Actin-Associated Proteins in Giardia lamblia.  

Science.gov (United States)

Consistent with its proposed status as an early branching eukaryote, Giardia has the most divergent actin of any eukaryote and lacks core actin regulators. Although conserved actin-binding proteins are missing from Giardia, its actin is utilized similarly to that of other eukaryotes and functions in core cellular processes such as cellular organization, endocytosis, and cytokinesis. We set out to identify actin-binding proteins in Giardia using affinity purification coupled with mass spectroscopy (multidimensional protein identification technology [MudPIT]) and have identified >80 putative actin-binding proteins. Several of these have homology to conserved proteins known to complex with actin for functions in the nucleus and flagella. We validated localization and interaction for seven of these proteins, including 14-3-3, a known cytoskeletal regulator with a controversial relationship to actin. Our results indicate that although Giardia lacks canonical actin-binding proteins, there is a conserved set of actin-interacting proteins that are evolutionarily indispensable and perhaps represent some of the earliest functions of the actin cytoskeleton. PMID:24728194

Paredez, Alexander R; Nayeri, Arash; Xu, Jennifer W; Krtková, Jana; Cande, W Zacheus

2014-06-01

324

Atrofia Villositaria Duodenal, un Hallazgo Inesperadamente Frecuente en Infestación por Giardia Lamblia / Duodenal villous atrophy, an unexpectedly common finding in giardia lamblia infestation  

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: Spanish Abstract in spanish OBJETIVO: Estudiar la presencia y frecuencia de los cambios histopatológicos tales como atrofia villositaria, linfocitosis intraepitelial, hiperplasia linfoide nodular y presencia de eosinófilos en biopsis duodenales informadas como Giardiasis. METODOLOGÍA: Se recolectó todos los casos diagnosticado [...] s como giardiasis duodenal durante el período 2005 a 2009 en 5 diferentes servicios de anatomía patológica y fueron revisados por un grupo de patólogos. RESULTADOS: Se incluyeron 30 casos. Se observó atrofia de las vellosidades en el 61,2%, incremento de linfocitos intraepiteliales en 63,3%, presencia de folículos linfoides en el 43,3% el promedio de eosinófilos en lámina propia por campo de alto poder fue aprox. 7. DISCUSIÓN: Nuestro porcentaje de atrofia villositaria es mucho mayor que lo reportado por otros autores, los casos con atrofia presentaron mayor frecuencia de linfocitosis 83,3% que los casos sin atrofia. (30%). Este hallazgo coincide con la relación directa entre linfocitos intraepiteliales /atrofia de vellosidades descrita por varios autores. Ninguno de los casos con hiperplasia linfoide, presentó ausencia de células plasmáticas que nos hiciera sospechar histológicamente de algún tipo de inmunodepresión humoral. El número de eosinófilos encontrado fue levemente elevado. Abstract in english OBJECTIVE: To study the histological changes observed in Giardia positive biopsies obtained from the duodenum.: The number of intraepithelial lymphocytes (IEL), grade of villous atrophy, presence of lymph follicles and number of eosinophils in the lamina propria per HPF were assessed. METHODS: All g [...] iardia positive biopsies diagnosed during period 2005-2009 in 5 pathology units were reevaluated by a group of pathologists. RESULTS: Thirty cases were included. Atrophic villous architecture was seen in 61,2%, increase in number of intraepithelial lymphocytes in 63,3% The occurrence of lymphoid follicles in 43,3%. DISCUSSION: Villous atrophy was higher than reported by others authors, cases with atrophy showed greater frequency of increase in the number of intraepithelial lymphocytes than cases without atrophy. No cases with lymph follicle showed lack of plasmatic cells, the number of eosinophils was subtly increased.

Fernando, Arévalo; Violeta, Aragón; Domingo, Morales L.; Domingo, Morales Caramutti; Jannitza, Arandia; Gabriel, Alcocer.

325

Longitudinal studies of Giardia contamination in two community drinking water supplies: cyst levels, parasite viability, and health impact.  

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Giardia cyst concentrations were determined in an inventory of 153 raw and 91 chlorinated drinking water samples collected at 86 sites from throughout the western Canadian province of British Columbia. Sixty-four percent of raw water samples were cyst positive (69% of sites). Cyst concentrations were lower in chlorinated than in raw water. The viability of cysts in drinking water samples assessed by infectivity in Mongolian gerbils (Meriones unguiculatus) was decreased in chlorinated water. T...

Isaac-renton, J.; Moorehead, W.; Ross, A.

1996-01-01

326

LOW PRESSURE ULTRAVIOLET STUDIES FOR INACTIVATION OF GIARDIA MURIS CYSTS  

Science.gov (United States)

This research was initiated to confirm and expand the current database for the inactivation of Giardia spp. using ultraviolet (UV) radiation. Initially, previous research that used in vitro excystation as the indicator for UV effectiveness was confirmed. Later, the in vitro excys...

327

LOW PRESSURE ULTRAVIOLET STUDIES FOR INACTIVIATION OF GIARDIA MURIS CYSTS  

Science.gov (United States)

This research was initiated to confirm and expand the current database for the inactiviation of Giardia spp. using ultraviolet (UV) radiation. The path taken was to confirm earlier UV research that used excystation as the indication of viability. In this study, an in vitro excyst...

328

Nucleotide sequence of a second alpha giardin gene and molecular analysis of the alpha giardin genes and transcripts in Giardia lamblia.  

Science.gov (United States)

The giardins are a group of proteins with relative molecular masses (Mrs) between 29,000 and 38,000 that are specific to the ventral disk of the intestinal protozoan parasite Giardia lamblia. We previously have characterized alpha-giardin, renamed here alpha-1-giardin, as a novel 33-kDa protein located on the edges of the disk microribbons. Southern blot analysis of G. lamblia genomic DNA, followed by cloning and sequencing, revealed the existence of a related gene that we have called alpha-2-giardin. Sequence comparison of the alpha-giardin genes reveals 81% identity at the nucleotide level and 77% at the predicted amino acid level. The predicted alpha-giardins have similar Mrs of approximately 33,900 and are very rich in alpha-helix conformations. Each gene is present in single copy and, like many other known Giardia coding sequences, exhibits a strong preference for cytidine and guanosine in the third base position of each codon. Chromosome hybridization analysis indicates that both genes are either on the same chromosome or on chromosomes with similar mobility. Experiments utilizing primer extension and RNA sequencing provide evidence that both genes are transcribed. The stable transcripts have extremely short leader regions of only 3 nucleotides, and the downstream sequence of the alpha-2-giardin gene reveals that the sequence AGTPuAA remains a consistent element within G. lamblia protein-encoding genes. PMID:1542319

Alonso, R A; Peattie, D A

1992-01-01

329

The risk of infection from Giardia lamblia due to drinking water supply, use of water, and latrines among preschool children in rural Lesotho.  

Science.gov (United States)

Stool samples were collected from 267 rural, preschool children in four districts in Lesotho during October-November, 1984. Sixty-three children (23.6%) were tested positive for Giardia lamblia, the most commonly recovered parasite from stool samples. The use of low amounts of water for personal hygiene was associated significantly with having G. lamblia (OR = 2.42), but the use of traditional, non-improved drinking water sources (OR = 1.38) or lack of latrines (OR = 0.94) was not. Although G. lamblia may be primarily waterborne in developed countries, the amount of water that is used for personal and domestic hygiene may be more important than the quality of drinking water in developing countries. Other risk factors that were identified to be associated significantly with having or not having Giardia were child older than 24 months (OR = 6.79), mother less than 20 years of age (OR = 5.18), residing in Mohales Hoek district (OR = 2.33), and possessing several agricultural tools (OR = 0.70). PMID:2722373

Esrey, S A; Collett, J; Miliotis, M D; Koornhof, H J; Makhale, P

1989-03-01

330

Técnicas de purificación y ruptura de quistes de Giardia spp Purification and breaking techniques of cysts of Giardia spp  

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Full Text Available El objetivo de este trabajo fue optimizar y evaluar las técnicas de purificación, aislamiento y ruptura de quistes de Giardia spp a partir de heces formoladas para la obtención de ADN. La materia fecal filtrada fue sometida a 3 técnicas de purificación, utilizando soluciones de formol-éter, sacarosa y formol-éter más sacarosa. La solución de sacarosa permitió aislar los quistes con menos detritos. Los quistes purificados fueron tratados con 3 técnicas para la ruptura de los mismos: shock osmótico y calor, degradación química y shock térmico, acción enzimática y efecto mecánico. Solamente con la técnica de shock térmico, acción enzimática y efecto mecánico se observaron bandas fluorescentes en geles de agarosa. Los resultados de este trabajo permiten contar con una metodología de rutina, simple, que podría ser usada en los pasos previos a la técnica de PCR para la genotipificación de este parásito.The purpose of this study was to optimize and evaluate the purification techniques, isolation and breaking of cysts of Giardia spp from fecal samples to isolate DNA. Filtrated fecal samples were tested in 3 purification techniques: Telleman solution, sucrose and Telleman plus sucrose. The sucrose solution let us to isolate the cysts with less detritus. The cleaned cysts were splited in 3 techniques to test the breaking: osmotic shock and heat, chemistry degradation and thermic shock, enzymatic action and mechanic effect. Only the last method was successful and showed bands in agarose gel. The result of this study shows a routine and common method which could be used in the previous steps to the PCR technique for the genotypification of these parasites.

D. Polverino

2004-09-01

331

The effect of hot water extract of Eucalyptus on Giardia lamblia parasite in vivo  

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Full Text Available The current study was conducted in the period from February 2012 till February 2013 to investigate the effect of Eucalyptus aqueous extract in G. lamblia in infected white mice Bulb/c. Flagyl was used in addition to the control solution (physiological solution as a control groups, the results of the study had been proved the effect of the extract by increasing the concentration without any side effect on the animals of the experiment and the results were as follows: The Eucalyptus extract 3000 mg/kg. is more efficient on G. lamblia compared with the Metronidazole and The 2000 mg/kg extract came next where it showed high treatment efficiency notably during the second day and finally the 1000 mg/kg extract came last which is the least effective during the 6th day compare with Flagyl, it was very effective during the fourth day. It was noticed, during a histological study of mice liver and small intestine tissues we notice hypoxia, necrosis, hypertrophy, and a congestion of blood vessels. There are significant differences for the Eucalyptus extract and Flagyl also with days treatment in compare with Flagyl.

Dr. Al - Quraishi Maher Ali

2013-08-01

332

An evaluation of methods for the simultaneous detection of Cryptosporidium oocysts and Giardia cysts from water.  

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Methods for the simultaneous detection of Cryptosporidium parvum oocysts and Giardia cysts from water are described and their relative recovery efficiencies are assessed for seeded samples of both tap and river water. Cartridge filtration, membrane filtration, and calcium carbonate flocculation were evaluated, and steps to optimize the concentration procedures were undertaken. Increasing centrifugation to 5,000 x g, coupled with staining in suspension, was found to increase the overall effici...

Shepherd, K. M.; Wyn-jones, A. P.

1996-01-01

333

Molecular characterization of Giardia duodenalis cysts in the Oreto River (Sicily, Southern Italy)  

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Background: The presence of Giardia was investigated along the Oreto river between January 2008 and May 2009 with the aim of understanding the source of contamination by molecular typing of cysts.

Methods: A total of 38 water samples (10 collected from the river mouth, 24 from the whole Oreto basin and 4 sewage samples from the Monreale treatment plant) were processed. In addition, 22 faecal samples of livest...

Maria Antonella Di Benedetto; Florinda Di Piazza; Carmelo Massimo Maida; Nino Romano

2010-01-01

334

CROSS-SPECIES TRANSMISSION OF GIARDIA: INOCULATION OF BEAVERS AND MUSKRATS WITH CYSTS OF HUMAN, BEAVER, MOUSE, AND MUSKRAT ORIGIN  

Science.gov (United States)

Giardia cysts isolated from humans, beavers, mice and muskrats were tested in cross-species transmission experiments for their ability to infect either beavers or muskrats. iardia cysts, derived from multiple symptomatic human donors and used for inoculation of beavers ormuskrats...

335

NEW METHOD TO DETERMINE 'GIARDIA' CYST VIABILITY: CORRELATION OF FLUORESCEIN DIACETATE AND PROPIDIUM IODIDE STAINING WITH ANIMAL INFECTIVITY  

Science.gov (United States)

The viability of Giardia muris cysts was studied using the fluorogenic dyes, fluorescein diacetate (FDA) and propidium iodide (PI). Using the mouse model for giardiasis, FDA or PI stained cysts were inoculated into neonatal mice. Feces were examined at days 3, 5, 8, and 11 post-i...

336

Giardia lamblia and other intestinal parasitic infections and their relationships with nutritional status in children in Brazilian Amazon Giardia lamblia e outros parasitas intestinais e sua relação com o status nutricional de crianças de uma área urbana na Amazônia Brasileira  

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Full Text Available The objective of this survey was to assess the relationships between intestinal parasitism, nutritional status and hemoglobin level in children with Indian ascendancy living in an urban area in Brazilian Amazon. We carried out a cross-sectional survey obtaining anthropometric, parasitological and socioeconomic data, and hemoglobin measurements of children aged six to 84 months. Anthropometric data were expressed as z-scores for weight for age (WAZ, height for age (HAZ, weight for height (WHZ and mid upper circumference for age (MUACZ parameters. Parasitological examinations were performed through Ritchie (n = 307, Kato-Katz (n = 278, Baermann-Moraes (n = 238 and Safranin-methylene blue methods (n = 307. Hemoglobin measurements were obtained with a Hemocue® photometer (n = 282. Socioeconomic data were used in order to classify children in three family income strata (n = 242. Multiple linear regression analysis showed independent interactions between Giardia lamblia and WAZ (beta = -0.195, SE = 0.138, p = 0.003, WHZ (beta = -0.161, SE = 0.133, p = 0.018 and MUACZ (beta = -0.197, SE = 0.143, p = 0.011, controlling for age, sex, family income, Ascaris lumbricoides, and hookworm infection. Also, the multivariate model showed that the only variable associated with hemoglobin levels was age. Intestinal parasitism control should increase children's possibilities of full development in the studied area.O presente estudo objetivou avaliar a relação entre as parasitoses intestinais, o status nutricional e os níveis de hemoglobina em crianças vivendo em uma área urbana na Amazônia Brasileira. Foi realizado um estudo seccional, obtendo-se dados antropométricos, parasitológicos e socioeconômicos, além de dosagens de hemoglobina através do fotômetro Hemocue®, de crianças com idade entre seis e 84 meses. Os dados da antropometria foram expressos como escores de desvio-padrão (escores z para os parâmetros peso-idade (PI, altura-idade (AI, peso-altura (PA e perímetro braquial-idade (PBI. Os exames parasitológicos foram realizados através dos métodos de Ritchie (n = 307, Kato-Katz (n = 278, Baermann-Moraes (n = 238 e Safranina-Azul-de-Metileno (n = 307. A regressão linear múltipla demonstrou interações independentes entre Giardia lamblia e PI (beta = -0.195, p = 0.003, PA (beta = -0.161, p = 0.018 e PBI (beta = -0.197, p = 0.011, após controle para idade, sexo, renda familiar e infecções por Ascaris lumbricoides e ancilostomídeos. O modelo multivariado demonstrou ainda que a única variável associada aos níveis de hemoglobina foi a idade. O estudo concluiu que a giardíase está associada, nos sujeitos pesquisados, a menores médias para os parâmetros antropométricos estudados e que um controle efetivo das parasitoses intestinais poderia contribuir para o pleno desenvolvimento das crianças na área estudada.

Filipe Anibal Carvalho-Costa

2007-06-01

337

Giardia lamblia and other intestinal parasitic infections and their relationships with nutritional status in children in Brazilian Amazon / Giardia lamblia e outros parasitas intestinais e sua relação com o status nutricional de crianças de uma área urbana na Amazônia Brasileira  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O presente estudo objetivou avaliar a relação entre as parasitoses intestinais, o status nutricional e os níveis de hemoglobina em crianças vivendo em uma área urbana na Amazônia Brasileira. Foi realizado um estudo seccional, obtendo-se dados antropométricos, parasitológicos e socioeconômicos, além [...] de dosagens de hemoglobina através do fotômetro Hemocue®, de crianças com idade entre seis e 84 meses. Os dados da antropometria foram expressos como escores de desvio-padrão (escores z) para os parâmetros peso-idade (PI), altura-idade (AI), peso-altura (PA) e perímetro braquial-idade (PBI). Os exames parasitológicos foram realizados através dos métodos de Ritchie (n = 307), Kato-Katz (n = 278), Baermann-Moraes (n = 238) e Safranina-Azul-de-Metileno (n = 307). A regressão linear múltipla demonstrou interações independentes entre Giardia lamblia e PI (beta = -0.195, p = 0.003), PA (beta = -0.161, p = 0.018) e PBI (beta = -0.197, p = 0.011), após controle para idade, sexo, renda familiar e infecções por Ascaris lumbricoides e ancilostomídeos. O modelo multivariado demonstrou ainda que a única variável associada aos níveis de hemoglobina foi a idade. O estudo concluiu que a giardíase está associada, nos sujeitos pesquisados, a menores médias para os parâmetros antropométricos estudados e que um controle efetivo das parasitoses intestinais poderia contribuir para o pleno desenvolvimento das crianças na área estudada. Abstract in english The objective of this survey was to assess the relationships between intestinal parasitism, nutritional status and hemoglobin level in children with Indian ascendancy living in an urban area in Brazilian Amazon. We carried out a cross-sectional survey obtaining anthropometric, parasitological and so [...] cioeconomic data, and hemoglobin measurements of children aged six to 84 months. Anthropometric data were expressed as z-scores for weight for age (WAZ), height for age (HAZ), weight for height (WHZ) and mid upper circumference for age (MUACZ) parameters. Parasitological examinations were performed through Ritchie (n = 307), Kato-Katz (n = 278), Baermann-Moraes (n = 238) and Safranin-methylene blue methods (n = 307). Hemoglobin measurements were obtained with a Hemocue® photometer (n = 282). Socioeconomic data were used in order to classify children in three family income strata (n = 242). Multiple linear regression analysis showed independent interactions between Giardia lamblia and WAZ (beta = -0.195, SE = 0.138, p = 0.003), WHZ (beta = -0.161, SE = 0.133, p = 0.018) and MUACZ (beta = -0.197, SE = 0.143, p = 0.011), controlling for age, sex, family income, Ascaris lumbricoides, and hookworm infection. Also, the multivariate model showed that the only variable associated with hemoglobin levels was age. Intestinal parasitism control should increase children's possibilities of full development in the studied area.

Filipe Anibal, Carvalho-Costa; Alessandra Queiroga, Gonçalves; Sandra Laranjeira, Lassance; Luanda Macedo da, Silva Neto; Carla Alexandra Almeida, Salmazo; Marcio Neves, Bóia.

338

Interleukin-6-Deficient Mice Are Highly Susceptible to Giardia lamblia Infection but Exhibit Normal Intestinal Immunoglobulin A Responses against the Parasite  

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In the present study, interleukin-6 (IL-6)-deficient mice were infected with Giardia lamblia clone GS/M-83-H7. Murine IL-6 deficiency did not affect the synthesis of parasite-specific intestinal immunoglobulin A. However, in contrast to wild-type mice, IL-6-deficient animals were not able to control the acute phase of parasite infection. Reverse transcription-PCR-based quantitation of cytokine mRNA levels in peripheral lymph node cells exhibited a short-term up-regulation of IL-4 expression i...

Bienz, Marianne; Dai, Wen Juan; Welle, Monika; Gottstein, Bruno; Mu?ller, Norbert

2003-01-01

339

Rational Design Synthesis and Evaluation of First Generation Inhibitors of the Giardia Lamblia Fructose-1 6-biphosphate Aldolase  

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Inhibitors of the Giardia lamblia fructose 1,6-bisphosphate aldolase (GlFBPA), which transforms fructose 1,6-bisphosphate (FBP) to dihydroxyacetone phosphate and glyceraldehyde 3-phosphate, were designed based on 3-hydroxy-2-pyridone and 1,2-dihydroxypyridine scaffolds that position two negatively charged tetrahedral groups for interaction with substrate phosphate binding residues, a hydrogen bond donor to the catalytic Asp83, and a Zn{sup 2+} binding group. The inhibition activities for the GlFBPA catalyzed reaction of FBP of the prepared alkyl phosphonate/phosphate substituted 3-hydroxy-2-pyridinones and a dihydroxypyridine were determined. The 3-hydroxy-2-pyridone inhibitor 8 was found to bind to GlFBPA with an affinity (K{sub i} = 14 {micro}M) that is comparable to that of FBP (K{sub m} = 2 {micro}M) or its inert analog TBP (K{sub i} = 1 {micro}M). The X-ray structure of the GlFBPA-inhibitor 8 complex (2.3 {angstrom}) shows that 8 binds to the active site in the manner predicted by in silico docking with the exception of coordination with Zn{sup 2+}. The observed distances and orientation of the pyridone ring O=C-C-OH relative to Zn{sup 2+} are not consistent with a strong interaction. To determine if Zn{sup 2+} coordination occurs in the GlFBPA-inhibitor 8 complex in solution, EXAFS spectra were measured. A four coordinate geometry comprised of the three enzyme histidine ligands and an oxygen atom from the pyridone ring O=C-C-OH was indicated. Analysis of the Zn{sup 2+} coordination geometries in recently reported structures of class II FBPAs suggests that strong Zn{sup 2+} coordination is reserved for the enediolate-like transition state, accounting for minimal contribution of Zn{sup 2+} coordination to binding of 8 to GlFBPA.

Z Li; Z Liu; D Cho; J Zou; M Gong; R Breece; A Galkin; L Li; H Zhao; et al.

2011-12-31

340

Sorting of encystation-specific cysteine protease to lysosome-like peripheral vacuoles in Giardia lamblia requires a conserved tyrosine-based motif.  

Science.gov (United States)

Encystation-specific cysteine protease (ESCP) was the first membrane-associated protein described to be part of the lysosome-like peripheral vacuoles in the intestinal parasite Giardia lamblia. ESCP is homologous to cathepsin C enzymes of higher eukaryotes, but is distinguished from other lysosomal cysteine proteases because it possesses a transmembrane domain and a short cytoplasmic tail. Tyrosine-based motifs within tails of membrane proteins are known to participate in endosomal/lysosomal protein sorting in higher eukaryotes. In this study, we show that a YRPI motif within the ESCP cytoplasmic tail is necessary and sufficient to mediate ESCP sorting to peripheral vacuoles in Giardia. Deletion and point mutation analysis demonstrated that the tyrosine residue is critical for ESCP sorting, whereas amino acids located at the Y+1 (Arg), Y+2 (Pro), and Y+3 (Ile) positions show minimal effect. Loss of the motif resulted in surface localization, whereas addition of the motif to a variant-specific surface protein resulted in lysosomal localization. Although Giardia trophozoites lack a morphologically discernible Golgi apparatus, our findings indicate that this parasite directs proteins to the lysosomes using a conserved sorting signal similar to that used by yeast and mammalian cells. Because Giardia is one of the earliest branching protist, these results demonstrate that sorting motifs for specific protein traffic developed very early during eukaryotic evolution. PMID:12466276

Touz, Maria C; Lujan, Hugo D; Hayes, Stanley F; Nash, Theodore E

2003-02-21

 
 
 
 
341

Giardia sp. Cysts and Infectious Cryptosporidium parvum Oocysts in the Feces of Migratory Canada Geese (Branta canadensis)  

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Fecal droppings of migratory Canada geese, Branta canadensis, collected from nine sites near the Chesapeake Bay (Maryland), were examined for the presence of Cryptosporidium parvum and Giardia spp. Cryptosporidium sp. oocysts were found in feces at seven of nine sites, and Giardia cysts were found at all nine sites. The oocysts from three sites were infectious for mice and molecularly identified as the zoonotic genotype of Cryptosporidium parvum. Waterfowl can disseminate infectious C. parvum...

Graczyk, Thaddeus K.; Fayer, Ronald; Trout, James M.; Lewis, Earl J.; Farley, C. Austin; Sulaiman, Irshad; Lal, Altaf A.

1998-01-01

342

Quantitative assessment of sense and antisense transcripts from genes involved in antigenic variation (vsp genes) and encystation (cwp 1 gene) of Giardia lamblia clone GS/M-83-H7.  

Science.gov (United States)

Antigenic variation of the intestinal protozoan parasite Giardia lamblia is caused by an exchange of the parasite's variant surface protein (VSP) coat. Many investigations on antigenic variation were performed with G. lamblia clone GS/M-83-H7 which produces surface antigen VSP H7. To generate novel information on giardial vsp gene transcription, vsp RNA levels were assessed by quantitative reverse transcription-(RT)-PCR in both axenic VSP H7-type trophozoites and subvariants obtained after negative selection of GS/M-83-H7 trophozoites by treatment with a cytotoxic, VSP H7-specific monoclonal antibody. Our investigation was not restricted to the assessment of the sense vsp transcript levels but also included an approach aimed at the detection of complementary antisense vsp transcripts within the two trophozoite populations. We found that sense vsp H7 RNA predominated in VSP H7-type trophozoites while sense RNA from only one (vsp IVg) of 8 subvariant vsp genes totally analysed predominated in subvariant-type trophozoites. Interestingly, the two trophozoite populations exhibited a similar relative distribution regarding the vsp H7 and vsp IVg antisense RNA molecules. An analogous sense versus antisense RNA pattern was also observed when the transcripts of gene cwp 1 (encoding cyst wall protein 1) were investigated. Here, both types of RNA molecules only appeared after cwp 1 had been induced through in vitro encystation of the parasite. These findings for the first time demonstrated that giardial antisense RNA production did not occur in a constitutive manner but was directly linked to complementary sense RNA production after activation of the respective gene systems. PMID:15830812

von Allmen, N; Bienz, M; Hemphill, A; Müller, N

2005-04-01

343

Disaccharidase activity in the small intestine of gerbils (Meriones unguiculatus) during primary and challenge infections with Giardia lamblia.  

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The sequence of changes in the activity of six disaccharidases in the small intestine of gerbils during primary and secondary G lamblia infections was examined. The primary G lamblia infection induced a transient reduction in disaccharidase activity which was related to the highest trophozoite burden in the small intestine. During the primary exposure, a 30% to 85% decrease in the activity of enzymes was observed on days 10 and 20 after infection. Secondary exposure of gerbils to G lamblia ca...

Belosevic, M.; Faubert, G. M.; Maclean, J. D.

1989-01-01

344

THE EFFICIENCY OF YARN WOUND FILTERS IN GIARDIA CYSTS REMOVAL USING THE IMPROVED SUCROSE GRADIENT  

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Full Text Available Introduction. The protozoan parasite Giardia is one of the important biological cotaminants in water. lts presence in water has caused the outbreak of a number of epidemics in various part of the world including the United States. The major impediment in detecting this particular parasite is unavailability of suitable filters capable of removing it from water. Regarding the fact yarn wound filters (cartridge used in removing Giardia under laboratory condition are currently difficult to obtain in Iran, attempts were made to design and manufacture the filters according to standards recommended in the literature. Methods. To determine the efficiency of filters manufactured in this way, a pilot system was established and parameters of concern were investigated. A given number of cysts were introduced in each case to the water in the pilot tank after being counted on the hemocytometer lamella After the entire tank water (at least 4001had been pumped through the filters, the filter were removed from the pilot system to have their yarns separated and washed. The cysts recovered were then counted and compared with the original input cysts to determine the efficiency of the filters. Formation of sediments on filters due to suspended solids in water was a great impediment in counting the cysts hidden in the sediments. To overcome this difficulty, the method of floatation in sucrose was used to remove the hidden cysts from the sediments. Regarding the morphological characteristics of the cysts, the method was also studied in terms of the sucrose film concentration and the effects of centrifugal speed and duration on the removal of cysts from sediments. Results. The results indicated an efficiency of 80.69±5.85, which was ideal for a first experience in Iran. a level of 2.5 molar of Sucrose with a duration of 10 minutes for the centrifugation time at 2,000 rpm were considered to be optimum levels to yield a certainty of 95 percent and an efficiency of 89.95±4.25 . Discussion. The comparison of the efficiency obtained with those obtained across the world from the application of other techniques associated with this method indicated that this filter was advantages to similar filters, keeping in mind also that this filter can be used in field situations. It is essential to modify in each region the method of cyst removal from sediments using Sucrose gradient according to the particular morphological characteristics and density of cystes. The optimization of Sucrose gradient and the centrifugation duration and speed seems equally important.

M.R SHAH MANSOURI

2001-09-01

345

A mitochondrial-like chaperonin 60 gene in Giardia lamblia: evidence that diplomonads once harbored an endosymbiont related to the progenitor of mitochondria.  

Science.gov (United States)

Diplomonads, parabasalids, as represented by trichomonads, and microsporidia are three protist lineages lacking mitochondria that branch earlier than all other eukaryotes in small subunit rRNA and elongation factor phylogenies. The absence of mitochondria and plastids in these organisms suggested that they diverged before the origin of these organelles. However, recent discoveries of mitochondrial-like heat shock protein 70 and/or chaperonin 60 (cpn60) genes in trichomonads and microsporidia imply that the ancestors of these two groups once harbored mitochondria or their endosymbiotic progenitors. In this report, we describe a mitochondrial-like cpn60 homolog from the diplomonad parasite Giardia lamblia. Northern and Western blots reveal that the expression of cpn60 is independent of cellular stress and, except during excystation, occurs throughout the G. lamblia life cycle. Phylogenetic analyses position the G. lamblia cpn60 in a clade that includes mitochondrial and hydrogenosomal cpn60 proteins. The most parsimonious interpretation of these data is that the cpn60 gene was transferred from the endosymbiotic ancestors of mitochondria to the nucleus early in eukaryotic evolution, before the divergence of the diplomonads and trichomonads from other extant eukaryotic lineages. A more complicated explanation requires that these genes originated from distinct alpha-proteobacterial endosymbioses that formed transiently within these protist lineages. PMID:9419358

Roger, A J; Svärd, S G; Tovar, J; Clark, C G; Smith, M W; Gillin, F D; Sogin, M L

1998-01-01

346

Climate and On-Farm Risk Factors Associated with Giardia duodenalis Cysts in Storm Runoff from California Coastal Dairies?  

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Climatic factors and on-farm management practices were evaluated for their association with the concentrations (cyst/liter) and instantaneous loads (cysts/second) of Giardia duodenalis in storm-based runoff from dairy lots and other high-cattle-use areas on five coastal California farms over two storm seasons. Direct fluorescent antibody analysis was used to quantitate cysts in 350 storm runoff samples. G. duodenalis was detected on all five dairy farms, with fluxes of 1 to 14,000 cysts/liter...

Miller, Woutrina A.; Lewis, David J.; Lennox, Michael; Pereira, Maria G. C.; Tate, Kenneth W.; Conrad, Patricia A.; Atwill, Edward R.

2007-01-01

347

Freqüencia da infecção por Giardia lamblia (Kunstler, 1882 em cães (Canis familiaris avaliada pelo Método de Faust e cols. (1939 e pela Coloração da Auramina, no município de Canoas, RS, Brasil Frequence of infection by Giardia lamblia (Kunstler, 1882 in dogs (Canis familiaris available trough the Faust and Collaborators Method (1939 and Auramine Staining in Canoas, RS, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available Giardia lamblia é um protozoário que acomete mais comumente animais jovens e que convivem em grupos. Apesar da alta prevalência, nem todos os animais apresentam a forma clínica da doença. Mesmo assim, a giardíase tem importância epidemiológica por possuir um elevado potencial zoonótico. O presente estudo teve como objetivo determinar a freqüência de Giardia lamblia em cães no município de Canoas, RS, Brasil, através do Método de Faust e cols. (1939 e da Técnica de Coloração da Auramina. Os grupos experimentais foram divididos de acordo com a procedência e o sexo. Das 332 amostras analisadas pelo Método de Faust e cols, a freqüência obtida foi de 34,04%, podendo variar de 28,95 a 39,13%, dentro de um intervalo de confiança de 95%. Destas amostras positivas, 40,96% foram de canil e 27,11% de cães de rua. O Teste Exato de Fisher aplicado a esses dados revelou existir uma diferença significativa (p=0,0107 entre as variáveis resultado e procedência. A variável sexo, neste método, não apresentou diferença significativa em relação ao resultado (P=0,8162 totalizando 33,11% de machos e 34,08% de fêmeas infectadas com o parasita. Das 147 amostras realizadas pela Técnica de Coloração da Auramina, 23 foram positivas, totalizando 15,65%. A análise estatística pelo Teste McNemar revelou existir diferença significativa entre as duas técnicas (P=0,0004. O valor Kappa foi igual a 0,07, considerado como um grau de concordância fraco. Os resultados encontrados neste estudo nos permitem afirmar que o Método de Faust e cols. foi o mais adequado para o diagnóstico da infecção por Giardia lamblia, sendo este parasita altamente prevalente na região estudada.Giardia lamblia is a protozoan that commonly infects young animals which live in groups. Despite its high prevalence many animals don’t exhibit clinical signs. Giardiasis is epidemiologically important concerning the zoonotic potential of the disease. The objective of this study was to determine the frequence of Giardia lamblia in the canine population of Canoas, RS, Brazil, applying the Faust and Collaborators Method (1939 and the Auramine Staining Technique. The dogs were classified according to the origin and gender. Feces samples of 332 dogs were analyzed by the Faust and Collaborators Method. The frequency of the infection obtained was 34.04%, ranging from 28.95% to 39.13% (confident interval at a 95% level. For kennel bred animals 40,96% of the samples were positive and for stray dogs 27.11%. Applying Fisher’s Exact Test to these figures there was a significant difference (P=0.0107 when comparing the origin of the animals and the results of the tests. However when comparing genders there was no significant difference (P=0.8162, the former with 33.11% of positive males and 34.08% positive females. When submitted to the Auramine Staining Technique(147 samples, 15.67% (23 of the samples resulted positive. The statistical analysis using the McNemar Test exposed a significant difference between both techniques (P=0.0004. The Kappa value of 0.07 obtained was considered of low rate. The results allow one to affirm that the Faust and Collaborators Method was the most suitable diagnostic test for Giardia lamblia infection, considering the high prevalence of this parasite in the studied region.

Cristiane Beck

2005-02-01

348

Freqüencia da infecção por Giardia lamblia (Kunstler, 1882) em cães (Canis familiaris) avaliada pelo Método de Faust e cols. (1939) e pela Coloração da Auramina, no município de Canoas, RS, Brasil / Frequence of infection by Giardia lamblia (Kunstler, 1882) in dogs (Canis familiaris) available trough the Faust and Collaborators Method (1939) and Auramine Staining in Canoas, RS, Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Giardia lamblia é um protozoário que acomete mais comumente animais jovens e que convivem em grupos. Apesar da alta prevalência, nem todos os animais apresentam a forma clínica da doença. Mesmo assim, a giardíase tem importância epidemiológica por possuir um elevado potencial zoonótico. O presente e [...] studo teve como objetivo determinar a freqüência de Giardia lamblia em cães no município de Canoas, RS, Brasil, através do Método de Faust e cols. (1939) e da Técnica de Coloração da Auramina. Os grupos experimentais foram divididos de acordo com a procedência e o sexo. Das 332 amostras analisadas pelo Método de Faust e cols, a freqüência obtida foi de 34,04%, podendo variar de 28,95 a 39,13%, dentro de um intervalo de confiança de 95%. Destas amostras positivas, 40,96% foram de canil e 27,11% de cães de rua. O Teste Exato de Fisher aplicado a esses dados revelou existir uma diferença significativa (p=0,0107) entre as variáveis resultado e procedência. A variável sexo, neste método, não apresentou diferença significativa em relação ao resultado (P=0,8162) totalizando 33,11% de machos e 34,08% de fêmeas infectadas com o parasita. Das 147 amostras realizadas pela Técnica de Coloração da Auramina, 23 foram positivas, totalizando 15,65%. A análise estatística pelo Teste McNemar revelou existir diferença significativa entre as duas técnicas (P=0,0004). O valor Kappa foi igual a 0,07, considerado como um grau de concordância fraco. Os resultados encontrados neste estudo nos permitem afirmar que o Método de Faust e cols. foi o mais adequado para o diagnóstico da infecção por Giardia lamblia, sendo este parasita altamente prevalente na região estudada. Abstract in english Giardia lamblia is a protozoan that commonly infects young animals which live in groups. Despite its high prevalence many animals don’t exhibit clinical signs. Giardiasis is epidemiologically important concerning the zoonotic potential of the disease. The objective of this study was to determine the [...] frequence of Giardia lamblia in the canine population of Canoas, RS, Brazil, applying the Faust and Collaborators Method (1939) and the Auramine Staining Technique. The dogs were classified according to the origin and gender. Feces samples of 332 dogs were analyzed by the Faust and Collaborators Method. The frequency of the infection obtained was 34.04%, ranging from 28.95% to 39.13% (confident interval at a 95% level). For kennel bred animals 40,96% of the samples were positive and for stray dogs 27.11%. Applying Fisher’s Exact Test to these figures there was a significant difference (P=0.0107) when comparing the origin of the animals and the results of the tests. However when comparing genders there was no significant difference (P=0.8162), the former with 33.11% of positive males and 34.08% positive females. When submitted to the Auramine Staining Technique(147 samples), 15.67% (23) of the samples resulted positive. The statistical analysis using the McNemar Test exposed a significant difference between both techniques (P=0.0004). The Kappa value of 0.07 obtained was considered of low rate. The results allow one to affirm that the Faust and Collaborators Method was the most suitable diagnostic test for Giardia lamblia infection, considering the high prevalence of this parasite in the studied region.

Cristiane, Beck; Flávio Antônio Pacheco de, Araújo; Adriana Tarnowski, Olicheski; Adriana Schneider, Breyer.

349

New system for higher recovery rate of water borne Cryptosporidium oocysts and Giardia cysts  

DEFF Research Database (Denmark)

Background: The two most common water borne pathogenic protozoa, Cryptosporidium and Giardia, cause diarrhea worldwide. Detecting these parasites in water samples depends on effective parasite recovery from the water matrix. The reported low recovery rates of the currently used filter methods motivate the development of systems with higher recovery rates. Materials and methods: Five replicates of IMS purified Cryptosporidium oocysts and Giardia cysts (N=2x103) were injected into a specially coated filter unit with a carefully chosen pore size. Following filtration, sonication was performed at predetermined time intervals to loosen all parasites and other particles from the filter and break up clusters. The concentrated parasite suspension was backwashed and counted after immuno-fluorescence staining. Results and discussion: Without sonication the recovery rates of both Cryptosporidium and Giardia were 85% were recorded when the filter was sonicated. Sonication usually affects parasite viability but could be tuned into a useful tool for enhanced backwash collection of parasites using a specially constructed filter unit and a sonication protocol. The filtration chamber further facilitated the concentration of parasites by ensuring a backwash volume of less than 1ml. The presented design of the filter system can be used as a cheap and time effective method of isolating water borne parasites in the laboratory.

Al-Sabi, Mohammad Nafi Solaiman; Enemark, Heidi L.

2012-01-01

350

Detection of Cryptosporidium oocysts and Giardia cysts in water samples with a Becton Dickinson FACSort flow cytometer  

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Current detection techniques for Cryptosporidium oocysts and Giardia cysts in water samples combine filtration of large volumes of water, concentration by centrifugation and flotation and immunofluorescense microscopy. The techniques are extremely labour-intensive and inefficient. The various steps in the sample processing procedures cause large losses of (oo)cysts resulting in an average overall recovery of about 3% in surface water samples. Microscopic interpretation of ...

Fm, Schets; Gj, Medema; Gd, Boschman

2007-01-01

351

The molecular mechanisms of giardia encystation.  

Science.gov (United States)

The protozoan parasite Giardia lamblia is transmitted as an environmentally resistant cyst. The encystation process is attracting attention not only from the viewpoint of disease transmission, but also as a model for differentiation. Here, Hugo Luján, Michael Mowatt and Theodore Nash discuss molecular events underlying this process, including the induction of expression and transport of cyst wall proteins and the induction of Golgi-like activity. They also propose that the signal for encystation derives from cholesterol deprivation in the lower small intestine. PMID:17040845

Luján, H D; Mowatt, M R; Nash, T E

1998-11-01

352

Evaluation of Five Membrane Filtration Methods for Recovery of Cryptosporidium and Giardia Isolates from Water Samples  

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We evaluated the efficiency of five membrane filters for recovery of Cryptosporidium parvum oocysts and Giardia lamblia cysts. These filters included the Pall Life Sciences Envirochek (EC) standard filtration and Envirochek high-volume (EC-HV) membrane filters, the Millipore flatbed membrane filter, the Sartorius flatbed membrane filter (SMF), and the Filta-Max (FM) depth filter. Distilled and surface water samples were spiked with 10 oocysts and 10 cysts/liter. We also evaluated the recovery...

2004-01-01

353

Occurrence of Cryptosporidium oocysts and Giardia cysts in raw water from the Atibaia river, Campinas, Brazil  

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Full Text Available Cryptosporidium parvum and Giardia duodenalis are waterborne parasites that have caused several outbreaks of gastrointestinal disease associated with drinking water. Due to the lack of studies about the occurrence of these protozoa in water in the Southeast of Brazil, an investigation was conducted to verify the presence of cysts and oocysts in superficial raw water of the Atibaia River. The water samples were submitted to membrane filtration (3.0 mum and elution was processed by (1 scraping and rinsing of membrane (RM method and (2 acetone-dissolution (ADM method. Microbiologic and chemical parameters were analyzed. Aliquots of the pellets were examined by immunofluorescence (Merifluor, Meridian Diagnostics, Cincinnati, Ohio. All water samples were positive for Cryptosporidium and Giardia, in spite of the high turbidity. Higher recovery rates occurred in samples treated by the RM method than by the ADM technique. The goal for future work is the assessment of viability of cysts and oocysts to determine the public health significance of this finding.

FRANCO Regina Maura Bueno

2001-01-01

354

Occurrence of Cryptosporidium oocysts and Giardia cysts in raw water from the Atibaia River, Campinas, Brazil.  

Science.gov (United States)

Cryptosporidium parvum and Giardia duodenalis are waterborne parasites that have caused several outbreaks of gastrointestinal disease associated with drinking water. Due to the lack of studies about the occurrence of these protozoa in water in the Southeast of Brazil, an investigation was conducted to verify the presence of cysts and oocysts in superficial raw water of the Atibaia River. The water samples were submitted to membrane filtration (3.0 microm) and elution was processed by (1) scraping and rinsing of membrane (RM method) and (2) acetone-dissolution (ADM method). Microbiologic and chemical parameters were analyzed. Aliquots of the pellets were examined by immunofluorescence (Merifluor, Meridian Diagnostics, Cincinnati, Ohio). All water samples were positive for Cryptosporidium and Giardia, in spite of the high turbidity. Higher recovery rates occurred in samples treated by the RM method than by the ADM technique. The goal for future work is the assessment of viability of cysts and oocysts to determine the public health significance of this finding. PMID:11340486

Franco, R M; Rocha-Eberhardt, R; Cantusio Neto, R

2001-01-01

355

Comparison of Animal Infectivity, Excystation, and Fluorogenic Dye as Measures of 'Giardia muris' Cyst Inactivation by Ozone.  

Science.gov (United States)

Giardia muris cyst viability after ozonation was compared by using fluorescein diacetate-ethidium bromide staining, the C3H/HeN mouse-G. muris model, and in vitro excystation. Bench-scale batch experiments were conducted under laboratory conditions (pH 6....

C. W. Labatiuk F. W. Schaefer G. R. Finch M. Belosevic

1991-01-01

356

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT PHYSICAL REMOVAL OF CRYPTOSPORIDIUM OOCYSTS AND GIARDIA CYSTS IN DRINKING WATER - PALL CORPORATION  

Science.gov (United States)

Verification testing of the Pall Corporation WPM-1 Microfiltration Pilot System was conducted from February 3 to March 5, 1999. The treatment system underwent microbial challenge testing on February 5, 1999, and demonstrated a 5.8 log10 removal of Giardia cysts and a 6.8 lo...

357

COMPARISON OF ANIMAL INFECTIVITY, EXCYSTATION AND FLUOROGENIC DYE AS MEASURES OF GIARDIA MURIS CYST INACTIVATION BY OZONE  

Science.gov (United States)

Giardia muris cyst viability following ozonation was compared using fluorescein diacetate-ethidium bromide staining, the C3H/HeN mouse-G. muris model, and in vitro excystation. ench-scale, batch experiments were conducted under laboratory conditions (pH 6.7; 22 degrees C) in ozon...

358

Determining the molecular mechanism of inactivation by chemical modification of triosephosphate isomerase from the human parasite Giardia lamblia: a study for antiparasitic drug design.  

Science.gov (United States)

Giardiasis, the most prevalent intestinal parasitosis in humans, is caused by Giardia lamblia. Current drug therapies have adverse effects on the host, and resistant strains against these drugs have been reported, demonstrating an urgent need to design more specific antigiardiasic drugs. ATP production in G. lamblia depends mainly on glycolysis; therefore, all enzymes of this pathway have been proposed as potential drug targets. We previously demonstrated that the glycolytic enzyme triosephosphate isomerase from G. lamblia (GlTIM), could be completely inactivated by low micromolar concentrations of thiol-reactive compounds, whereas, in the same conditions, the activity of human TIM (HuTIM) was almost unaltered. We found that the chemical modification (derivatization) of at least one Cys, of the five Cys residues per monomer in GlTIM, causes this inactivation. In this study, structural and functional studies were performed to describe the molecular mechanism of GlTIM inactivation by thiol-reactive compounds. We found that the Cys222 derivatization is responsible for GlTIM inactivation; this information is relevant because HuTIM has a Cys residue in an equivalent position (Cys217). GlTIM inactivation is associated with a decrease in ligand affinity, which affects the entropic component of ligand binding. In summary, this work describes a mechanism of inactivation that has not been previously reported for TIMs from other parasites and furthermore, we show that the difference in reactivity between the Cys222 in GlTIM and the Cys217 in HuTIM, indicates that the surrounding environment of each Cys residue has unique structural differences that can be exploited to design specific antigiardiasic drugs. PMID:21786322

Enríquez-Flores, Sergio; Rodríguez-Romero, Adela; Hernández-Alcántara, Gloria; Oria-Hernández, Jesús; Gutiérrez-Castrellón, Pedro; Pérez-Hernández, Gerardo; de la Mora-de la Mora, Ignacio; Castillo-Villanueva, Adriana; García-Torres, Itzhel; Méndez, Sara T; Gómez-Manzo, Saúl; Torres-Arroyo, Angélica; López-Velázquez, Gabriel; Reyes-Vivas, Horacio

2011-09-01

359

ETV STATEMENT - PHYSICAL REMOVAL OF CRYPTOSPORIDIUM OOCYSTS AND GIARDIA CYSTS IN DRINKING WATER - ZENON ZEEWEED ZW500 ULTRAFILTRATION MEMBRANE SYSTEM AT PITTSBURGH, PA  

Science.gov (United States)

Verification testing of the ZENON Environmental Inc. ZeeWeed ZW500 UF Drinking Water System was conducted from 2/6-3/7/99. The treatment system underwent Giardia and Cryptosporidium removal challenge testing on 3/2/99 and demonstrated a 5.3 log10 removal of Giardia cysts and a 6...

360

Temporal changes in the prevalence and shedding patterns of Giardia duodenalis cysts and Cryptosporidium spp. oocysts in a herd of dairy calves in Ontario  

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Giardia duodenalis and Cryptosporidium spp. infections, and the patterns of cyst and oocyst shedding, were observed in a herd of dairy calves in Ontario over a period of 3 mo. Cysts and oocysts were detected and enumerated in fecal samples using immunofluorescence microscopy; Giardia and Cryptosporidium DNA was detected using the polymerase chain reaction. The prevalence of G. duodenalis increased during the course of the study, reaching a peak of 93.1% when calves were 43 to 54 d old, and th...

Coklin, Tatjana; Farber, Jeffrey M.; Parrington, Lorna J.; Coklin, Z?arko; Ross, William H.; Dixon, Brent R.

2010-01-01

 
 
 
 
361

Avaliação de massas específicas de cistos de Giardia duodenalis e Entamoeba coli Evaluation of specific gravity of Giardia duodenalis and E. coli cysts  

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Full Text Available Cistos de Giardia duodenalis e Entamoeba coli foram observados quanto à flutuação em soluções de sacarose de massas específicas diversas (1.040, 1.050, 1.060, 1.070,1.080,1.090,1.100, 1.150,1.200 e 1.250 kg/m³, contidas em câmaras de contagem de 0,17 mm de altura. Contaram-se os cistos que flutuaram e os que sedimentaram tendo sido calculadas as porcentagens respectivas. As diferenças de flutuabilidade dos cistos de cada uma das espécies não foram consideráveis. Soluções de massa específica igual a 1.200 kg/m³ fizeram flutuar 88,49% dos cistos de G. duodenalis e 95,71% dos de E. coli. Os maiores valores de flutuabilidade estiveram associados à massa específica 1.250 kg/m³ e foram, respectivamente, 89,15% e 98,59% para cistos de G. duodenalis e de E. coli.Cysts of Giardia duodenalis and Entamoeba coli were observed as for flotability in sucrose solutions of different specific gravity, contained in counting-chambers of 0.17 mm height. The cysts that floated and those that sedimented were counted and then calculated the respective percentage. Flotability differences of the cysts of each species were not considerable. Solutions of specific gravity 1,200 kg/m³ made 88.49% of G. duodenalis cysts and 95.71% of E. coli cysts float. The greater values of flotability were associated to specific gravity 1,250 kg/m³ and were 89.15% and 98.59% for cysts of G. duodenalis and E. coli, respectively.

Maria da Luz Ribeiro Moitinho

1992-10-01

362

ALTERNATIVE FILTRATION METHODS FOR REMOVAL OF 'GIARDIA' CYSTS AND CYST MODELS  

Science.gov (United States)

Recent occurrence of numerous outbreaks of waterborne giardiasis has renewed interest in water filtration for cyst removal. This paper presents an in-depth review of granular media and diatomaceous earth (D.E.) filtration research conducted in the 1930's and 1940's when Entamoeba...

363

Effects of Ultrasound on the Survival and Characteristics of Cryptosporidium Oocysts and Giardia Cysts  

DEFF Research Database (Denmark)

Background: Sonication of fluids has been widely used for cell lyses and decontamination of water and food due to its three major physical and chemical effects: cavitation, implosion of water bubbles with subsequent increase in substrate temperature and liberation of free radicals such as O-. Additionally ultrasound has been used for cleaning filters used for water sampling and purification. Other studies have shown that backwash sampling of filtrates, and thereby collection of microorganisms, can be facilitated by sonication. Methods: We studied the effects of ultrasound with different sonication power and time durations on two of the most common waterborne protozoa Cryptosporidium and Giardia, and examined its effects on parasite characteristics and survival rate using immunofluorescence dyes; DAPI (4â??,6-diamidino-2-phenylindol) staining/PI (propidium iodide), and analyzed by flow cytometry. Results: The results showed that exposure of Cryptosporidium oocysts and Giardia cysts to ultrasound could reduce their survival rate even if the exposure time was limited to a few seconds. When sonication time was extended, changes in parasite characteristics became clearly visible. Several other factors determine the effects of ultrasound on the parasite, including the sonication power of ultrasound as well as substrate temperature. Conclusions: Ultrasound is harmful for waterborne protozoa even when momentarily applied. However, a mode of operation may exist in which ultrasound can be used for collection of parasites for further study. The specific operational conditions may be tailored to control survival rates and collection efficiency.

Al-Sabi, Mohammad Nafi Solaiman; Gad, J.

2011-01-01

364

Quantification of viable Giardia cysts and Cryptosporidium oocysts in wastewater using propidium monoazide quantitative real-time PCR.  

Science.gov (United States)

Real-time PCR (qPCR) is a rapid tool to quantify pathogens in the aquatic environment; however, it quantifies all pathogens, including both viable and nonviable. Propidium monoazide (PMA) is a membrane-impairment dye that penetrates only membrane-damaged cells. Once inside the cell, PMA is covalently cross-linked to DNA through light photoactivation, and PCR amplification is strongly inhibited. The goal of this study was to evaluate PMA-qPCR assays for rapid quantification of viable and heat-treated Giardia cysts and Cryptosporidium oocysts in wastewater. We observed a reduction in detection of heat-treated Giardia duodenalis cysts of 83.2, 89.9, 98.2, or 97 % with PMA-qPCR assays amplifying a 75 base-pair (bp) ?-giardin target, 77-bp triosephosphate isomerase (tpi), 133-bp glutamate dehydrogenase (GDH), and 143-bp ?-giardin gene target, respectively. Thus, the exclusion of dead cysts was more effective when qPCR assays that produced larger amplicons were used. The PMA treatment of Cryptosporidium oocysts plus/minus heat treatment abolished the fluorescent signal for dead oocysts with a PMA-qPCR assay amplifying a Cryptosporidium parvum (150-bp) oocyst wall protein (COWP) gene. The PMA-qPCR 143-bp ?-giardin assay for Giardia and the PMA-qPCR 150-bp COWP assay for Cryptosporidium accurately quantified live oo(cysts), and failed to detect dead oo(cysts), when phosphate-buffered saline and tertiary effluent wastewater were spiked with concentrations of 10(3) or 10(2) dead oo(cysts), respectively. Therefore, these assays are suitable for the detection of viable parasites that are typically present in tertiary wastewater effluents at concentrations of <10(3) oo(cysts)/l and can provide rapid risk assessments of environmental water. PMID:24781028

Alonso, José L; Amorós, Inmaculada; Guy, Rebecca A

2014-07-01

365

'GIARDIA' DETECTION IN WATER SYSTEMS  

Science.gov (United States)

A method has been developed combining immunofluorescence and phase-contrast to microscopically locate and identify Giardia cysts among particulates filtered from water samples. Selective staining of cysts with anti-Giardia antiserum and a fluorochrom enhances the contrast between...

366

Evaluation of a new monoclonal antibody combination reagent for direct fluorescence detection of Giardia cysts and Cryptosporidium oocysts in human fecal specimens.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giardia lamblia and Cryptosporidium parvum can cause severe symptoms in humans, particularly in the immunologically compromised. Monoclonal antibody reagents offer increased sensitivity and an excellent alternative to conventional staining methods. These reagents are helpful when screening large numbers of patients or those with minimal symptoms. Problems of false-positive and false-negative results with routine staining methods for stool parasites can be eliminated with monoclonal antibody r...

Garcia, L. S.; Shum, A. C.; Bruckner, D. A.

1992-01-01

367

Apo and calcium-bound crystal structures of cytoskeletal protein alpha-14 giardin (annexin E1) from the intestinal protozoan parasite Giardia lamblia.  

Science.gov (United States)

Alpha-14 giardin (annexin E1), a member of the alpha giardin family of annexins, has been shown to localize to the flagella of the intestinal protozoan parasite Giardia lamblia. Alpha giardins show a common ancestry with the annexins, a family of proteins most of which bind to phospholipids and cellular membranes in a Ca(2+)-dependent manner and are implicated in numerous membrane-related processes including cytoskeletal rearrangements and membrane organization. It has been proposed that alpha-14 giardin may play a significant role during the cytoskeletal rearrangement during differentiation of Giardia. To gain a better understanding of alpha-14 giardin's mode of action and its biological role, we have determined the three-dimensional structure of alpha-14 giardin and its phospholipid-binding properties. Here, we report the apo crystal structure of alpha-14 giardin determined in two different crystal forms as well as the Ca(2+)-bound crystal structure of alpha-14 giardin, refined to 1.9, 1.6 and 1.65 A, respectively. Although the overall fold of alpha-14 giardin is similar to that of alpha-11 giardin, multiwavelength anomalous dispersion phasing was required to solve the alpha-14 giardin structure, indicating significant structural differences between these two members of the alpha giardin family. Unlike most annexin structures, which typically possess N-terminal domains, alpha-14 giardin is composed of only a core domain, followed by a C-terminal extension that may serve as a ligand for binding to cytoskeletal protein partners in Giardia. In the Ca(2+)-bound structure we detected five bound calcium ions, one of which is a novel, highly coordinated calcium-binding site not previously observed in annexin structures. This novel high-affinity calcium-binding site is composed of seven protein donor groups, a feature rarely observed in crystal structures. In addition, phospholipid-binding assays suggest that alpha-14 giardin exhibits calcium-dependent binding to phospholipids that coordinate cytoskeletal disassembly/assembly during differentiation of the parasite. PMID:19046974

Pathuri, Puja; Nguyen, Emily Tam; Ozorowski, Gabriel; Svärd, Staffan G; Luecke, Hartmut

2009-01-30

368

Evaluation of rapid commercial enzyme immunoassay for detection of Giardia lamblia in formalin-preserved stool specimens.  

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Two hundred twenty-three formalin-preserved stool specimens were evaluated by using ProSpecT Giardia Rapid Assay (membrane bound) (Alexon, Inc., Sunnyvale, Calif.). Enzyme immunoassay (EIA) results were compared with those by conventional microscopic examination. Two hundred four specimens were negative by both methods, and 13 (6.3%) were positive. Five specimens were negative by initial microscopic exam and positive by EIA; three of these specimens were found to be positive upon extensive mi...

Scheffler, E. H.; Etta, L. L.

1994-01-01

369

Comparison of animal infectivity, excystation, and fluorogenic dye as measures of Giardia muris cyst inactivation by ozone  

Energy Technology Data Exchange (ETDEWEB)

Giardia muris cyst viability after ozonation was compared by using fluorescein diacetate-ethidium bromide staining, the C3H/HeN mouse-G. muris model, and in vitro excystation. Bench-scale batch experiments were conducted under laboratory conditions (pH 6.7, 22C) in ozone-demand-free phosphate buffer. There was a significant difference between fluorogenic staining and infectivity with fluorogenic staining overestimating viability compared with infectivity estimates of viability. This suggests that viable cysts as indicated by fluorogenic dyes may not be able to complete the life cycle and produce an infection. No significant differences between infectivity and excystation and between fluorogenic staining and excystation were detected for inactivations up to 99.9%. Only animal infectivity had the sensitivity to detect inactivations greater than 99.9%. Therefore, the animal model is the best method currently available for detecting high levels of G. muris cyst inactivation.

Labatiuk, C.W.; Finch, G.R.; Belosevic, M. (Univ. of Alberta, Edmonton (Canada)); Schaefer, F.W. III (Environmental Protection Agency, Cincinnati, OH (United States))

1991-11-01

370

Detection of Giardia cysts with a cDNA probe and applications to water samples.  

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Giardiasis is the most common human parasite infection in the United States, causing a lengthy course of diarrhea. Transmission of Giardia species is by the fecal-oral route, and numerous waterborne outbreaks have been documented. The Environmental Protection Agency has regulated Giardia species in drinking water through the Surface Water Treatment Rule. Current methods for detection of Giardia species in water rely primarily on microscopic observation of water concentrates with immunofluores...

Abbaszadegan, M.; Gerba, C. P.; Rose, J. B.

1991-01-01

371

Comparison of animal infectivity, excystation, and fluorogenic dye as measures of Giardia muris cyst inactivation by ozone.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giardia muris cyst viability after ozonation was compared by using fluorescein diacetate-ethidium bromide staining, the C3H/HeN mouse-G. muris model, and in vitro excystation. Bench-scale batch experiments were conducted under laboratory conditions (pH 6.7, 22 degrees C) in ozone-demand-free phosphate buffer. There was a significant difference between fluorogenic staining and infectivity (P less than or equal to 0.05), with fluorogenic staining overestimating viability compared with infectivi...

Labatiuk, C. W.; Schaefer, F. W.; Finch, G. R.; Belosevic, M.

1991-01-01

372

THE EFFICIENCY OF YARN WOUND FILTERS IN GIARDIA CYSTS REMOVAL USING THE IMPROVED SUCROSE GRADIENT  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Introduction. The protozoan parasite Giardia is one of the important biological cotaminants in water. lts presence in water has caused the outbreak of a number of epidemics in various part of the world including the United States. The major impediment in detecting this particular parasite is unavailability of suitable filters capable of removing it from water. Regarding the fact yarn wound filters (cartridge) used in removing Giardia under laboratory condition are currently difficult to obtai...

2001-01-01

373

The abundance of Cryptosporidium and Giardia spp. in treated effluents produced by four wastewater treatment plants in the Gauteng Province of South Africa  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english This study aimed at assessing the effectiveness of 4 wastewater treatment plants of the Gauteng Province, namely Zeekoegat, Baviaanspoort, Rayton and Refilwe Water Care Works (WCW), in the removal of Cryptosporidium and Giardia (oo)cysts. Wastewater influent and treated effluent samples were taken w [...] eekly between January and April 2008. Cryptosporidium and Giardia (oo)cysts were detected by immunofluorescence and immunomagnetic separation, according to a modified US EPA 1623 method. Effluent samples were subjected to a molecular study for the identification of Cryptosporidium parvum Genotype I and Giardia lamblia Assemblage A. The 18S rRNA gene for restriction digests was therefore used to characterise these (oo)cysts. Cryptosporidium oocysts were repeatedly detected in effluent samples collected from all wastewater treatments at lower concentration (range

M, Dungeni; MNB, Momba.

374

Comparative Analysis of the 15.5kD Box C/D snoRNP Core Protein in the Primitive Eukaryote Giardia lamblia Reveals Unique Structural and Functional Features  

Energy Technology Data Exchange (ETDEWEB)

Box C/D ribonucleoproteins (RNP) guide the 2'-O-methylation of targeted nucleotides in archaeal and eukaryotic rRNAs. The archaeal L7Ae and eukaryotic 15.5kD box C/D RNP core protein homologues initiate RNP assembly by recognizing kink-turn (K-turn) motifs. The crystal structure of the 15.5kD core protein from the primitive eukaryote Giardia lamblia is described here to a resolution of 1.8 {angstrom}. The Giardia 15.5kD protein exhibits the typical {alpha}-{beta}-{alpha} sandwich fold exhibited by both archaeal L7Ae and eukaryotic 15.5kD proteins. Characteristic of eukaryotic homologues, the Giardia 15.5kD protein binds the K-turn motif but not the variant K-loop motif. The highly conserved residues of loop 9, critical for RNA binding, also exhibit conformations similar to those of the human 15.5kD protein when bound to the K-turn motif. However, comparative sequence analysis indicated a distinct evolutionary position between Archaea and Eukarya. Indeed, assessment of the Giardia 15.5kD protein in denaturing experiments demonstrated an intermediate stability in protein structure when compared with that of the eukaryotic mouse 15.5kD and archaeal Methanocaldococcus jannaschii L7Ae proteins. Most notable was the ability of the Giardia 15.5kD protein to assemble in vitro a catalytically active chimeric box C/D RNP utilizing the archaeal M. jannaschii Nop56/58 and fibrillarin core proteins. In contrast, a catalytically competent chimeric RNP could not be assembled using the mouse 15.5kD protein. Collectively, these analyses suggest that the G. lamblia 15.5kD protein occupies a unique position in the evolution of this box C/D RNP core protein retaining structural and functional features characteristic of both archaeal L7Ae and higher eukaryotic 15.5kD homologues.

Biswas, Shyamasri; Buhrman, Greg; Gagnon, Keith; Mattos, Carla; Brown, II, Bernard A.; Maxwell, E. Stuart (NCSU); (UTSMC)

2012-07-11

375

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT PHYSICAL REMOVAL CRYPTOSPROIDIUM OOCYSTS AND GIARDIA CYSTS IN DRINKING WATER  

Science.gov (United States)

Verification testing of the ZENON Environmental Inc. ZeeWeed ZW-500 UF Drinking Water System was conducted from February 6 to March 7, 1999. The treatment system underwent Giardia and Cryptosporidium removal challenge testing on March 2, 1999, and demonstrated a 5.3 log10 removal...

376

Method to enumerate oocysts of cryptosporidium and cysts of Giardia in water; Metodi per il rilevamento dei cisti e oocisti di protozoi patogeni nelle acque  

Energy Technology Data Exchange (ETDEWEB)

Cryptosporidium and Giardia have been recognized as etiological agents of gastrointestinal illness in humans with severe consequences on children and immunocompromised individuals. Water seems to be vehicle of infection. In last years many efforts have been done to evaluate a method to enumerate oocysts of Cryptosporidium and cysts of Giardia in waters. Throughout filtration and concentration steps, the two procedures proposed allow to enumerate oocysts and cysts belonging to the two genera of protozoa. [Italian] Cryptosporidium e Giardia sono protozoi parassiti responsabili di gravi forme di gastroenterite nell'uomo e in particolare negli individui immunocompromessi e nei bambini. Perche' e' considerata il primo veicolo di infezione, il controllo della diffusione dei due parassiti nei corpi idrici, pone come prioritaria la necessita' di disporre di metodi di analisi facilmente applicabili ed efficienti. Attraverso fasi di filtrazione e di concentrazione, i metodi di seguito proposti consentono la determinazione quantitativa, a livello di genere, di oocisti di Cryptosporidium e di cisti di Giardia nelle acque.

Briancesco, R.; Bonadonna, L. [Istituto Superiore di Sanita' , Rome (Italy). Lab. di Igiene Ambientale

2000-02-01

377

Genotyping of Giardia isolates in Scotland: a descriptive epidemiological study.  

Science.gov (United States)

SUMMARY Giardiasis, caused by the intestinal protozoan parasite Giardia intestinalis (synonyms: G. lamblia, G. duodenalis), is one of the most frequent parasites to infect the Scottish population. Transmission of the infective cysts in faecal matter is commonly via food and/or water. Giardia is subdivided into assemblages, where clinical and epidemiological differences have been described between assemblages A and B. This snapshot descriptive epidemiological study examines 30 positive cases of Giardia of which 72% (n = 21) were shown to be assemblage A, 14% (n = 4) assemblage B and 10% (n = 3) mixed assemblages (A and B). There was a 2:3 female:male ratio of affected individuals with foreign travel recorded in 22 of these cases. The commonest symptom was diarrhoea which was reported in 80% of cases followed by tiredness. Five cases required hospitalization emphasizing the importance of gaining a greater understanding of how Giardia assemblages influence clinical outcomes to assist in formulating guidelines to manage potential Giardia outbreaks. PMID:24125434

Alexander, C; Jones, B; Inverarity, D; Pollock, K G J

2014-08-01

378

NL MIND-BEST: a web server for ligands and proteins discovery--theoretic-experimental study of proteins of Giardia lamblia and new compounds active against Plasmodium falciparum.  

Science.gov (United States)

There are many protein ligands and/or drugs described with very different affinity to a large number of target proteins or receptors. In this work, we selected Ligands or Drug-target pairs (DTPs/nDTPs) of drugs with high affinity/non-affinity for different targets. Quantitative Structure-Activity Relationships (QSAR) models become a very useful tool in this context to substantially reduce time and resources consuming experiments. Unfortunately most QSAR models predict activity against only one protein target and/or have not been implemented in the form of public web server freely accessible online to the scientific community. To solve this problem, we developed here a multi-target QSAR (mt-QSAR) classifier using the MARCH-INSIDE technique to calculate structural parameters of drug and target plus one Artificial Neuronal Network (ANN) to seek the model. The best ANN model found is a Multi-Layer Perceptron (MLP) with profile MLP 20:20-15-1:1. This MLP classifies correctly 611 out of 678 DTPs (sensitivity=90.12%) and 3083 out of 3408 nDTPs (specificity=90.46%), corresponding to training accuracy=90.41%. The validation of the model was carried out by means of external predicting series. The model classifies correctly 310 out of 338 DTPs (sensitivity=91.72%) and 1527 out of 1674 nDTP (specificity=91.22%) in validation series, corresponding to total accuracy=91.30% for validation series (predictability). This model favorably compares with other ANN models developed in this work and Machine Learning classifiers published before to address the same problem in different aspects. We implemented the present model at web portal Bio-AIMS in the form of an online server called: Non-Linear MARCH-INSIDE Nested Drug-Bank Exploration & Screening Tool (NL MIND-BEST), which is located at URL: http://miaja.tic.udc.es/Bio-AIMS/NL-MIND-BEST.php. This online tool is based on PHP/HTML/Python and MARCH-INSIDE routines. Finally we illustrated two practical uses of this server with two different experiments. In experiment 1, we report by first time Quantum QSAR study, synthesis, characterization, and experimental assay of antiplasmodial and cytotoxic activities of oxoisoaporphine alkaloids derivatives as well as NL MIND-BEST prediction of potential target proteins. In experiment 2, we report sampling, parasite culture, sample preparation, 2-DE, MALDI-TOF, and -TOF/TOF MS, MASCOT search, MM/MD 3D structure modeling, and NL MIND-BEST prediction for different peptides a new protein of the found in the proteome of the human parasite Giardia lamblia, which is promising for anti-parasite drug-targets discovery. PMID:21277861

González-Díaz, Humberto; Prado-Prado, Francisco; Sobarzo-Sánchez, Eduardo; Haddad, Mohamed; Maurel Chevalley, Séverine; Valentin, Alexis; Quetin-Leclercq, Joëlle; Dea-Ayuela, María A; Teresa Gomez-Muños, María; Munteanu, Cristian R; José Torres-Labandeira, Juan; García-Mera, Xerardo; Tapia, Ricardo A; Ubeira, Florencio M

2011-05-01

379

Modifications to United States Environmental Protection Agency Methods 1622 and 1623 for Detection of Cryptosporidium Oocysts and Giardia Cysts in Water  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Collaborative and in-house laboratory trials were conducted to evaluate Cryptosporidium oocyst and Giardia cyst recoveries from source and finished-water samples by utilizing the Filta-Max system and U.S. Environmental Protection Agency (EPA) methods 1622 and 1623. Collaborative trials with the Filta-Max system were conducted in accordance with manufacturer protocols for sample collection and processing. The mean oocyst recovery from seeded, filtered tap water was 48.4% ± 11.8%, while the me...

Mccuin, Randi M.; Clancy, Jennifer L.

2003-01-01

380

Development of a quantitative PCR (qPCR) for Giardia and analysis of the prevalence, cyst shedding and genotypes of Giardia present in sheep across four states in Australia.  

Science.gov (United States)

A novel quantitative PCR (qPCR) for Giardia at the glutamate dehydrogenase (gdh) locus was developed and validated. The qPCR was used to screen a total of 3412 lamb faecal samples collected from approximately 1189 lambs at three sampling periods (weaning, post-weaning and pre-slaughter) from eight farms across South Australia (SA), New South Wales (NSW), Victoria (Vic) and Western Australia (WA). The overall prevalence was 20.2% (95% CI 18.9-21.6) and of the 690 positives, 473 were successfully typed. In general, the prevalence of Giardia varied widely across the different farms with the highest prevalence in one WA farm (42.1%) at pre-slaughter sampling and the lowest prevalence in one Victorian farm (7.2%) at weaning. The range of cyst shedding at weaning, post-weaning and pre-slaughter overall across all states was 63-1.3×10(9) cysts g(-1) (median=1.7×10(4)), 63-1.1×10(9) cysts g(-1) (median=9.6×10(3)), 63-4.7×10(9) cysts g(-1) (median=8.1×10(4)) respectively. Assemblage specific primers at the triose phosphate isomerase (tpi) locus identified assemblage A in 22.4% (106/473) of positive samples typed, assemblage E in 75.9% (359/473) and mixed A and E assemblages in 1.7% (8/473) of samples. A subset of representative samples from the 8 farms (n=32) were typed at both the gdh and beta-giardin loci and confirmed these results and identified sub-assemblage AII in 16 representative assemblage A isolates across the 8 farms. This demonstrates a prevalence of Giardia previously not recognised in Australian sheep, highlighting a need for further research to quantify the production impacts of this protozoan parasite. PMID:24355868

Yang, Rongchang; Jacobson, Caroline; Gardner, Graham; Carmichael, Ian; Campbell, Angus J D; Ryan, Una

2014-02-01

 
 
 
 
381

Quantitation of Giardia cysts and Cryptosporidium oocysts in fecal samples by direct immunofluorescence assay.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The lack of quick, simple, and sensitive quantitative tests has impeded studies on infection patterns and treatment of Giardia spp. and Cryptosporidium spp. A quantitative direct immunofluorescence assay (FA) using a commercial FA kit was developed and evaluated. Recovery rates of the FA for Cryptosporidium oocysts in calf feces seeded with 1,000, 10,000, 100,000, and 1,000,000 oocysts per g were 14.8, 40.8, 84.2, and 78.2%, respectively. Interassay coefficients of variation were 10.6 to 47.1...

Xiao, L.; Herd, R. P.

1993-01-01

382

Detecção de oocistos de Cryptosporidium spp. e cistos de Giardia spp. em amostras de esgoto bruto ou tratado: avaliação crítica dos métodos / Detection of Cryptosporidium spp. oocysts and Giardia spp. cysts in raw and effluent wastewater: critical evaluation of methods  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Neste trabalho, avaliou-se a eficiência dos métodos centrífugo-concentração e filtração em membrana, na detecção de oocistos de Cryptosporidium spp. e cistos de Giardia spp. em amostras de esgoto bruto e tratado, provenientes de um sistema de lodos ativados (estação de tratamento de esgoto, Samambai [...] a, Campinas, em São Paulo). As amostras foram coletadas quinzenalmente por dois anos: 53 amostras de esgoto bruto (AFL), 53 de efluente tratado sem desinfecção por luz ultravioleta (EFL) e 38 de efluente tratado e desinfetado por luz ultravioleta (EFL+UV). Cistos de Giardia spp. foram encontrados em 90,5% das amostras AFL; em 96,2%, de EFL; e em 94,7%, de EFL+UV. Oocistos de Cryptosporidium spp. foram detectados em 6,4% das amostras AFL e em 2,6 % de EFL+UV. Ambos os métodos mostraram-se eficientes na detecção destes protozoários em todos os tipos de amostras, além de apresentarem baixo custo por análise. Abstract in english In this study, the efficiency of centrifuge-concentration and membrane filtrated methods was evaluated in the detection of Cryptosporidium spp. oocysts and Giardia spp. cysts in raw or treated wastewater samples, from activated sludge systems (ETE - Samambaia, Campinas, in São Paulo). The samples we [...] re collected once a fortnight for two years: 53 samples of influent (AFL), 53 samples of treated effluent without ultraviolet disinfection (EFL), and 38 samples of treated effluent with ultraviolet disinfection (EFL+UV). Giardia spp. cysts were found in 90.5% of the AFL samples; in 96.2% of the samples, EFL; and in 94.7%, EFL+UV. Cryptosporidium spp. oocysts were detected in 6.4% of AFL samples and 2.6% of EFL+UV. Both methods showed efficiency when detecting protozoa in all types of samples, besides having low costs by analysis.

Luciana Urbano dos, Santos; Romeu, Cantusio Neto; Regina Maura Bueno, Franco; José Roberto, Guimarães.

383

Detecção de oocistos de Cryptosporidium spp. e cistos de Giardia spp. em amostras de esgoto bruto ou tratado: avaliação crítica dos métodos Detection of Cryptosporidium spp. oocysts and Giardia spp. cysts in raw and effluent wastewater: critical evaluation of methods  

Directory of Open Access Journals (Sweden)

Full Text Available Neste trabalho, avaliou-se a eficiência dos métodos centrífugo-concentração e filtração em membrana, na detecção de oocistos de Cryptosporidium spp. e cistos de Giardia spp. em amostras de esgoto bruto e tratado, provenientes de um sistema de lodos ativados (estação de tratamento de esgoto, Samambaia, Campinas, em São Paulo. As amostras foram coletadas quinzenalmente por dois anos: 53 amostras de esgoto bruto (AFL, 53 de efluente tratado sem desinfecção por luz ultravioleta (EFL e 38 de efluente tratado e desinfetado por luz ultravioleta (EFL+UV. Cistos de Giardia spp. foram encontrados em 90,5% das amostras AFL; em 96,2%, de EFL; e em 94,7%, de EFL+UV. Oocistos de Cryptosporidium spp. foram detectados em 6,4% das amostras AFL e em 2,6 % de EFL+UV. Ambos os métodos mostraram-se eficientes na detecção destes protozoários em todos os tipos de amostras, além de apresentarem baixo custo por análise.In this study, the efficiency of centrifuge-concentration and membrane filtrated methods was evaluated in the detection of Cryptosporidium spp. oocysts and Giardia spp. cysts in raw or treated wastewater samples, from activated sludge systems (ETE - Samambaia, Campinas, in São Paulo. The samples were collected once a fortnight for two years: 53 samples of influent (AFL, 53 samples of treated effluent without ultraviolet disinfection (EFL, and 38 samples of treated effluent with ultraviolet disinfection (EFL+UV. Giardia spp. cysts were found in 90.5% of the AFL samples; in 96.2% of the samples, EFL; and in 94.7%, EFL+UV. Cryptosporidium spp. oocysts were detected in 6.4% of AFL samples and 2.6% of EFL+UV. Both methods showed efficiency when detecting protozoa in all types of samples, besides having low costs by analysis.

Luciana Urbano dos Santos

2011-06-01

384

CROSS TRANSMISSION OF 'GIARDIA'  

Science.gov (United States)

Giardia cysts isolated from fecal samples obtained from humans (Homo sapiens), beaver (Castor canadensis), dogs (Canis familiaris), cats (Felis domesticus), bighorn X mouflon sheep (Ovis canadensis X O. musimon), guinea pig (Cavis porcellus), muskrat (Ondatra ziethica) and mule d...

385

'GIARDIA' METHODS WORKSHOP  

Science.gov (United States)

The objectives of the workshop were to familiarize participants with the use-and limitations of Giardia cyst detection methodology; to critically review the tentative Giardia method appearing in the 16th edition of Standard Methods for the Examination of Water and Wastewater; to ...

386

Occurrence of Giardia cysts and Cryptosporidium oocysts in activated sludge samples in Campinas, SP, Brazil Ocorrência de cistos de Giardia e oocistos de Cryptosporidium em amostras de lodo ativado em Campinas, SP, Brasil  

Directory of Open Access Journals (Sweden)

Full Text Available Giardia and Cryptosporidium have caused several outbreaks of gastroenteritis in humans associated with drinking water. Contaminated sewage effluents are recognized as a potential source of waterborne protozoa. Due to the lack of studies about the occurrence of these parasites in sewage samples in Brazil, we compared the efficiency of two procedures for concentrating cysts and oocysts in activated sludge samples of one sewage treatment plant. For this, the samples were submitted to i concentration by the ether clarification procedure (ECP and to ii purification by sucrose flotation method (SFM and aliquots of the pellets were examined by immunofluorescence. Giardia cysts were present in all samples (100.0%; n = 8 when using ECP and kit 1 reagents, while kit 2 resulted in six positive samples (85.7%; n = 7. As for SFM, cysts were detected in 75.0% and 100.0% of these samples (for kit 1 and 2, respectively. Regarding Cryptosporidium, two samples (25.0%; kit 1 and 28.5% for kit 2 were detected positive by using ECP, while for SFM, only one sample (examined by kit 1 was positive (12.5%. The results of the control trial revealed Giardia and Cryptosporidium recovery efficiency rates for ECP of 54.5% and 9.6%, while SFM was 10.5% and 3.2%, respectively. Considering the high concentration detected, a previous evaluation of the activated sludge before its application in agriculture is recommended and with some improvement, ECP would be an appropriate simple technique for protozoa detection in sewage samples.Giardia e Cryptosporidium causaram vários surtos epidêmicos de gastroenterite, associados à água potável. Efluentes de esgoto contaminados foram incriminados como uma fonte potencial de cistos e oocistos. Uma investigação foi conduzida para verificar a presença de cistos de Giardia e oocistos de Cryptosporidium em amostras de lodo ativado de uma Estação de Tratamento de Esgoto. Para isto as amostras foram submetidas: i a concentração pelo processo de clarificação com éter (ECP e ii método de purificação por flutuação em sacarose (SFM e, as alíquotas dos sedimentos foram examinadas por imunofluorescência. Cistos de Giardia estiveram presentes em todas as amostras avaliadas (100,0%; n = 8 quando utilizado ECP e kit 1, enquanto o kit 2 resultou em 6 amostras positivas (85,7%; n = 7. Para SFM, cistos de Giardia foram detectados em 75,0% e 100,0% destas amostras (para kit 1 e 2 respectivamente. Considerando os oocistos de Cryptosporidium, duas amostras (25,0%; kit 1 e 28,5% kit 2 foram positivas usando-se ECP enquanto para SFM, apenas uma amostra (examinada pelo kit 1 foi positiva (12,5%. Os resultados do experimento-controle revelaram que as taxas de recuperação para Giardia e Cryptosporidium, quando utilizado ECP foi de 54,5% e 9,6% e para SFM, foi de 10,5% e 3,2%, respectivamente. Considerando a detecção de alta concentração desses protozoários, é recomendada a avaliação prévia do lodo ativado antes de sua aplicação na agricultura e, com alguma melhora, ECP pode ser uma técnica apropriada e simples para a detecção de protozoários em amostras de esgoto.

Luciana Urbano Santos

2004-04-01

387

Diagnostic testing for Giardia infections.  

Science.gov (United States)

The traditional method for diagnosing Giardia infections involves microscopic examination of faecal specimens for Giardia cysts. This method is subjective and relies on observer experience. From the 1980s onwards, objective techniques have been developed for diagnosing Giardia infections, and are superseding diagnostic techniques reliant on microscopy. Detection of Giardia antigen(s) by immunoassay is the basis of commercially available diagnostic kits. Various nucleic acid amplification techniques (NAATs) can demonstrate DNA of Giardia intestinalis, and have the potential to become standard approaches for diagnosing Giardia infections. Of such techniques, methods involving either fluorescent microspheres (Luminex) or isothermal amplification of DNA (loop-mediated isothermal amplification; LAMP) are especially promising. PMID:24463773

Heyworth, Martin F

2014-03-01

388

MoDW Part 14 - Crypto & Giardia  

…Appendix 3 Typical recovery efficiencies quoted for Cryptosporidium oocysts and Giardia cysts 82 Appendix 4 Validation procedures 84 Appendix 5 Images of Cryptosporidium oocysts and Giardia cysts and (oo)cyst-like bodies 107 Address for correspondence 130 Members assisting with this booklet 130 6 About… Related Searches: microbiology of drinking water part 3

389

Occurrence of Cryptosporidium oocysts and Giardia cysts in raw water from the Atibaia river, Campinas, Brazil / Ocorrência de oocistos de Cryptosporidium e cistos de Giardia em águas do Rio Atibaia, Campinas, Brasil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Cryptosporidium parvum e Giardia duodenalis são parasitos transmitidos pela água e têm causado muitos surtos de doenças gastrointestinais associados à ingestão de água. Devido à falta de estudo sobre a ocorrência destes protozoários na água, no Sudeste do Brasil, uma investigação foi conduzida para [...] verificar a presença de cistos e oocistos na água superficial do rio Atibaia. As amostras de água foram submetidas à filtração em membrana e a eluição foi processada por: (1) lavagem e raspagem da membrana (RM) e (2) dissolução em acetona (ADM). Parâmetros microbiológicos e químicos foram analisados. Alíquotas do sedimento foram examinadas por imunofluorescência. Todas as amostras de água foram positivas, a despeito da alta turbidez. Maior taxa de recuperação ocorreu em amostras tratadas pelo RM que por ADM. A meta em futuros trabalhos é determinar a viabilidade de cistos e oocistos para se obter o significado deste achado em Saúde Pública. Abstract in english Cryptosporidium parvum and Giardia duodenalis are waterborne parasites that have caused several outbreaks of gastrointestinal disease associated with drinking water. Due to the lack of studies about the occurrence of these protozoa in water in the Southeast of Brazil, an investigation was conducted [...] to verify the presence of cysts and oocysts in superficial raw water of the Atibaia River. The water samples were submitted to membrane filtration (3.0 mum) and elution was processed by (1) scraping and rinsing of membrane (RM method) and (2) acetone-dissolution (ADM method). Microbiologic and chemical parameters were analyzed. Aliquots of the pellets were examined by immunofluorescence (Merifluor, Meridian Diagnostics, Cincinnati, Ohio). All water samples were positive for Cryptosporidium and Giardia, in spite of the high turbidity. Higher recovery rates occurred in samples treated by the RM method than by the ADM technique. The goal for future work is the assessment of viability of cysts and oocysts to determine the public health significance of this finding.

Regina Maura Bueno, FRANCO; Rosângela, ROCHA-EBERHARDT; Romeu, CANTUSIO NETO.

390

Cysts  

Science.gov (United States)

... main types of cysts found in the brain: Arachnoid Cyst (also called Leptomeningeal Cyst): An enlarged, fluid-filled ... in a variety of locations within the brain. Arachnoid Cysts appear in the subarachnoid space (between the arachnoid ...

391

Identification of Variant-Specific Surface Proteins in Giardia muris Trophozoites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giardia lamblia undergoes antigenic variation, a process that might allow the parasite to evade the host's immune response and adapt to different environments. Here we show that Giardia muris, a related species that naturally infects rodents, possesses multiple variant-specific surface proteins (VSPs) and expresses VSPs on its surface, suggesting that it undergoes antigenic variation similar to that of G. lamblia.

Ropolo, Andrea S.; Saura, Alicia; Carranza, Pedro G.; Lujan, Hugo D.

2005-01-01

392

ETV REPORT - PHYSICAL REMOVAL OF CRYPTOSPORIDIUM OOCYSTS AND GIARDIA CYSTS IN DRINKING WATER AQUASOURCE NORTH AMERICA ULTRAFILTRATION SYSTEM A35 AT PITTSBURGH, PA. - NSF00/07/EPADW395  

Science.gov (United States)

Verification testing of the Aquasource Ultrafiltration Treatment System Model A35 was conducted from 12/1 - 12/31/98. The treatment system underwent microbial challenge testing on 1/22/99 and demonstrated a 5.5 log10 removal of Giardia cysts and a 6.5 log10 removal of Cryptospori...

393

Improvement of recoveries for the determination of protozoa Cryptosporidium and Giardia in water using method 1623.  

Science.gov (United States)

The U.S. Environmental Protection Agency has developed method 1623 for simultaneous detection of Cryptosporidium oocysts and Giardia cysts in water. Method 1623 includes four major steps: filtration, immunomagnetic separation (IMS), fluorescent antibody (FA) staining and microscopic examination. It was noted that the recovery levels following IMS-FA and FA staining were high, averaging more than 92.0% and 89.0% for C. parvum oocysts and G. lamblia cysts, respectively. In contrast, when the filtration step was incorporated, the recovery level of C. parvum oocysts declined significantly to 18.1% in seeded tap water, while a relatively high recovery level of 77.2% for G. lamblia cysts could still be achieved. Further study indicated that the recovery level of C. parvum oocysts could be enhanced significantly when an appropriate amount of silica particles was added to a water sample. The recovery level of C. parvum oocysts was affected by particle size and concentration. The optimal silica particle size was determined to be within the range of 5-40 microm, and the corresponding optimal silica concentration was 1.42 g for 10-l tap water. When both G. lamblia cysts and C. parvum oocysts were spiked into the tap water sample containing the optimum amount of silica particles, the average recovery levels of oocysts and cysts were 82.7% and 75.4%, respectively. The results obtained clearly suggested that addition of an appropriate amount of silica particles could improve the recovery level of C. parvum oocysts significantly and yet there was no noticeable deleterious effect on the recovery level of G. lamblia cysts. Further study indicated that the rotation time in the IMS procedure using the Dynal GC-Combo IMS kit (which was recommended in method 1623) was important for G. lamblia cyst detection. In contrast, the recovery level of C. parvum oocysts was not affected by the rotation time. Furthermore, it was found that the recovery levels of C. parvum oocysts using methods 1622 and 1623 were quite close although different IMS kits were used in the two methods. PMID:15279936

Hu, Jiangyong; Feng, Yaoyu; Ong, Say Leong; Ng, Wun Jern; Song, Lianfa; Tan, Xiaolan; Chu, Xiaona

2004-09-01

394

MoDW Part 14 - Crypto & Giardia  

…identification and enumeration of Cryptosporidium oocysts and Giardia cysts Methods for the Examination of Waters and Associated Materials 2 The Microbiology of Drinking Water (2010) - Part 14 - Methods for the isolation, identification and enumeration of Cryptosporidium oocysts and Giardia cysts Methods… Related Searches: microbiology of drinking water part 3

395

MoDW Part 14 - Crypto & Giardia  

…enumeration of Cryptosporidium oocysts and Giardia cysts Methods for the Examination of Waters and Associated Materials 2 The Microbiology of Drinking Water (2010) - Part 14 - Methods for the isolation, identification and enumeration of Cryptosporidium oocysts and Giardia cysts Methods for the Examination of… Related Searches: microbiology of drinking water part 3

396

Diarrea crónica refractaria y malabsorción secundaria a hipogammaglobulinemia común variable, infestación crónica por giardia lamblia y gastrectomía total por adenocarcinoma gástrico: un manejo nutricional complejo / Chonic diarrhea and malabsorption due to common variable immunodeficiency, gastrectomy and giardiasis infection: a difficult nutritional management  

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish El adenocarcinoma gástrico es una de las causas más frecuentes de mortalidad en el mundo, siendo la cirugía el único tratamiento potencialmente curativo, aunque los efectos adversos digestivos y nutricionales son frecuentes y abundantes. La hipogammaglobulinemia variable común es causa de frecuentes [...] manifestaciones digestivas, derivándose las más importantes en diarrea crónica causada por giardiasis, hiperplasia nodular linfoide o atrofia vellosa, siendo frecuente la malabsorción y la desnutrición. Los déficits nutricionales secundarios a la malabsorción (postgastrectomía y asociada a la atrofia vellosa y la giardiasis por hipogammaglobulinemia variable común) son asimismo frecuentes. Presentamos el caso de un paciente gastrectomizado por adenocarcinoma gástrico y con hipogammaglobulinemia variable común e infestación crónica por giardiasis que presenta una importante diarrea crónica refractaria a tratamiento y malabsorción. Abstract in english Gastric cancer is a frequent cause of cancer-related mortality in the world. Surgery is the only potentially curative therapy, although the adverse effects of surgery are common and considerable. Common variable immunodeficiency is in many cases cause of gastrointestinal system problems such as chro [...] nic diarrhea caused by infestation with giardia lamblia, nodular lymphoid hiperplasia ad loss of villi leading frequently to malapsortion and malnutrition. Nutritional deficiencies due to malapsorption (postgastrectomy and secondary to loss of villi, giardiasis and common variable inmunodeficiency) are common. We present the case of a patient with gastric cancer who underwent a gastrectomy with common variable hipogammaglobulinemia and chronic infestation by giardia lamblia, with serious diarrhea resistant to treatment and malabsorption.

M. E., Domínguez-López; I., González-Molero; C. P., Ramírez-Plaza; F., Soriguer; G., Olveira.

397

Host-Pathogen Responses during Giardia infections  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giardia lamblia is a eukaryotic parasite of the upper small intestine of humans and animals. The infecting trophozoite cells do not invade the epithelium lining of the intestine, but attach to the brush border surface in the intestinal lumen. The giardiasis disease in humans is highly variable. Prior to this study, the molecular mechanisms involved in establishment of infection or cause of disease were largely uncharacterized. In this thesis, the molecular relationship between Giardia and the...

Ringqvist, Emma

2009-01-01

398

Isolation of Giardia from a llama and from sheep.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giardia cysts were detected in feces of a domestic llama (Lama glama) and in feces of lambs (Ovis aries) from Wisconsin, U.S.A. All of the animals examined were immature, and they had recent histories of poor condition and passing unformed or semiformed, pale stools. Giardia cysts from both host species were excysted in vitro, and the trophozoites were cultivated axenically. Furthermore, Giardia cysts from both sources were shown to produce infection in Mongolian gerbils (Meriones unquiculatu...

Kiorpes, A. L.; Kirkpatrick, C. E.; Bowman, D. D.

1987-01-01

399

Genotyping of Giardia duodenalis cysts by new real-time PCR assays for detection of mixed infections in human samples  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Of the seven genetic groups, or assemblages, currently recognized in the Giardia duodenalis species complex, only assemblages A and B are associated with human infection, but they also infect other mammals. Recent investigations have suggested the occurrence of genetic exchanges among isolates of G. duodenalis, and the application of assemblage-specific PCR has shown both assemblages A and B in a significant number of human infections. In this work, three real-time quantitative (qPCR) assays ...

Almeida, Andre?; Pozio, Edoardo; Caccio?, Simone M.

2010-01-01

400

Strategies to discover the structural components of cyst and oocyst walls.  

Science.gov (United States)

Cysts of Giardia lamblia and Entamoeba histolytica and oocysts of Toxoplasma gondii and Cryptosporidium parvum are the infectious and sometimes diagnostic forms of these parasites. To discover the structural components of cyst and oocyst walls, we have developed strategies based upon a few simple assumptions. Briefly, the most abundant wall proteins are identified by monoclonal antibodies or mass spectrometry. Structural components include a sugar polysaccharide (chitin for Entamoeba, ?-1,3-linked glucose for Toxoplasma, and ?-1,3-linked GalNAc for Giardia) and/or acid-fast lipids (Toxoplasma and Cryptosporidium). Because Entamoeba cysts and Toxoplasma oocysts are difficult to obtain, studies of walls of nonhuman pathogens (E. invadens and Eimeria, respectively) accelerate discovery. Biochemical methods to dissect fungal walls work well for cyst and oocyst walls, although the results are often unexpected. For example, echinocandins, which inhibit glucan synthases and kill fungi, arrest the development of oocyst walls and block their release into the intestinal lumen. Candida walls are coated with mannans, while Entamoeba cysts are coated in a dextran-like glucose polymer. Models for cyst and oocyst walls derive from their structural components and organization within the wall. Cyst walls are composed of chitin fibrils and lectins that bind chitin (Entamoeba) or fibrils of the ?-1,3-GalNAc polymer and lectins that bind the polymer (Giardia). Oocyst walls of Toxoplasma have two distinct layers that resemble those of fungi (?-1,3-glucan in the inner layer) or mycobacteria (acid-fast lipids in the outer layer). Oocyst walls of Cryptosporidium have a rigid bilayer of acid-fast lipids and inner layer of oocyst wall proteins. PMID:24096907

Samuelson, John; Bushkin, G Guy; Chatterjee, Aparajita; Robbins, Phillips W

2013-12-01

 
 
 
 
401

Role of predation by zooplankton in transport and fate of protozoan (oo)cysts in granular activated carbon filtration.  

Science.gov (United States)

The significance of zooplankton in the transport and fate of pathogenic organisms in drinking water is poorly understood, although many hints of the role of predation in the persistence of microorganisms through water treatment processes can be found in literature. The objective of this study was to assess the impact of predation by natural zooplankton on the transport and fate of protozoan (oo)cysts in granular activated carbon (GAC) filtration process. UV-irradiated unlabelled Cryptosporidium parvum and Giardia lamblia (oo)cysts were seeded into two pilot-scale GAC filtration columns operated under full-scale conditions. In a two-week period after seeding, a reduction of free