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

Ortega-Barrı́a, Eduardo; Ward, Honorine; Keusch, Gerald T.; Pereira, M. E. A.

doi:10.1172/jci117591

Cited by 28 publications

(24 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5), with no DNA replication detected even after 48 h in culture. These findings contrast with those previously described for lectins, which led to arrest in a later phase (G 2 /M) of the cell cycle (27). Interestingly, differentiation into cysts takes place from the G 2 phase (2), and thus the extracellular factors produced by La1, can prevent giardia from producing cysts that in turn will diminish the spreading of the parasite.…”

Section: Discussioncontrasting

confidence: 77%

Inhibition of Giardia intestinalis by Extracellular Factors from Lactobacilli: an In Vitro Study

Pérez

Minnaard

Rouvet

et al. 2001

Appl Environ Microbiol

105

View full text Add to dashboard Cite

The aim of the present work was to evaluate the effect of spent culture supernatants of different strains of lactobacilli on giardia trophozoites. The growth of Giardia intestinalis strain WB, as well as the attachment to the human intestinal epithelial cell line Caco-2, was evaluated by using proliferation and adhesion assays with radiolabeled parasites. In addition, scanning electron microscopy and flow cytometric analysis were performed. The effect of spent culture supernatants from lactobacilli was strain dependent. Lactobacillus johnsonii La1 significantly inhibited the proliferation of G. intestinalis trophozoites. Although the effect was strongly pH dependent, it was not simply due to lactic acid. According to flow cytometric analysis, trophozoites were arrested in G 1 phase but neither significant necrosis nor apoptosis could be detected. Bacterial cells or their spent culture supernatants were unable to modify trophozoite attachment to Caco-2 cells. However, trophozoites treated with spent culture supernatants had little, if any, proliferative capacity. These results suggest that La1 produces some substance(s) able to inhibit proliferation of Giardia trophozoites. Partial characterization of the factors involved in the antigiardiasic action showed that they have a low molecular mass and are inactivated by heating. On this basis, it seems worthwhile to explore how colonization of the proximal small bowel with these lactic acid bacteria could interfere with giardiasis in vivo.

show abstract

Section: Discussioncontrasting

confidence: 77%

Inhibition of Giardia intestinalis by Extracellular Factors from Lactobacilli: an In Vitro Study

Pérez

Minnaard

Rouvet

et al. 2001

Appl Environ Microbiol

105

View full text Add to dashboard Cite

show abstract

“…Through the course of this work, we observed that previously published flow cytometry DNA distributions of Giardia trophozoites showed wide unresolved peaks which were difficult to interpret (7,17,21). Recent advances in Giardia flow cytometry protocols (4) greatly improved peak resolution but were not readily reproducible in our laboratory.…”

Section: Resultsmentioning

confidence: 93%

Cell Cycle Synchrony in Giardia intestinalis Cultures Achieved by Using Nocodazole and Aphidicolin

2008

View full text Add to dashboard Cite

Giardia intestinalis is a ubiquitous intestinal protozoan parasite and has been proposed to represent the earliest diverging lineage of extant eukaryotes. Despite the importance of Giardia as a model organism, research on Giardia has been hampered by an inability to achieve cell cycle synchrony for in vitro cultures. This report details successful methods for attaining cell cycle synchrony in Giardia cultures. The research presented here demonstrates reversible cell cycle arrest in G 1 /S and G 2 /M with aphidicolin and nocodazole, respectively. Following synchronization, cells were able to recover completely from drug treatment and remained viable and maintained synchronous growth for 6 h. These techniques were used to synchronize Giardia cultures to increase the percentages of mitotic spindles in the cultures. This method of synchronization will enhance our ability to study cell cycle-dependent processes in G. intestinalis.

show abstract

“…The effect of alcohol treatment on G. duodenalis infections is much greater than that of oral consumption of whole wheat and/or wheat germ, which contain WGA and are common components of the human diet. In a rodent model and in human infections, WGA, which binds to short N-glycans of G. duodenalis and reduces excystation in vitro, showed modest reduction in cysts shed and in symptoms (humans) (37)(38)(39). A commercial alcohol-based hand sanitizer killed E. invadens cysts directly applied to the hands, validating the findings when E. invadens cysts were treated with alcohols in a microcentrifuge tube and dried in the rotary evaporator.…”

Section: Discussionmentioning

confidence: 54%

Ethanol and Isopropanol in Concentrations Present in Hand Sanitizers Sharply Reduce Excystation of Giardia and Entamoeba and Eliminate Oral Infectivity of Giardia Cysts in Gerbils

Chatterjee

Bandini

Motari

et al. 2015

Antimicrob Agents Chemother

View full text Add to dashboard Cite

Enteric protozoan parasites, which are spread by the fecal-oral route, are important causes of diarrhea (Giardia duodenalis) and amebic dysentery (Entamoeba histolytica). Cyst walls of Giardia and Entamoeba have a single layer composed of fibrils of ␤-1,3-linked GalNAc and ␤-1,4-linked GlcNAc (chitin), respectively. The goal here was to determine whether hand sanitizers that contain ethanol or isopropanol as the active microbicide might reduce transmission of these parasites. We found that treatment with these alcohols with or without drying in a rotary evaporator (to model rapid evaporation of sanitizers on hands) kills 85 to 100% of cysts of G. duodenalis and 90 to 100% of cysts of Entamoeba invadens (a nonpathogenic model for E. histolytica), as shown by nuclear labeling with propidium iodide and failure to excyst in vitro. Alcohols with or without drying collapsed the cyst walls of Giardia but did not collapse the cyst walls of Entamoeba. To validate the in vitro results, we showed that treatment with alcohols eliminated oral infection of gerbils by 1,000 G. duodenalis cysts, while a commercial hand sanitizer (Purell) killed E. invadens cysts that were directly applied to the hands. These results suggest that expanded use of alcohol-based hand sanitizers might reduce the transmission of Giardia and Entamoeba. G iardia duodenalis (also known as Giardia lamblia)is an important cause of human diarrhea in both the developing and developed world and is an important zoonosis of companion and production animals (1-8). Entamoeba histolytica may cause amebic dysentery and liver abscess, primarily in the developing world (9-11). Because these parasites may cause severe infections and are readily transmitted by asymptomatic carriers, the National Institute of Allergy and Infectious Diseases (NIAID) has designated Giardia and Entamoeba category B priority pathogens.Our laboratory has extensively characterized the cyst walls of Giardia and Entamoeba, each of which contains a prominent sugar polymer and a small set of proteins (12, 13). In contrast, the Saccharomyces cerevisiae cell wall contains two sugar polymers (chitin and ␤-1,3-linked glucan) and ϳ100 glycoproteins (14). The Giardia cyst wall contains curled fibrils of ␤-1,3-linked N-acetylgalactosamine (GalNAc) and cyst wall proteins (CWPs) that bind the GalNAc homopolymer (15, 16). Cyst wall proteins have very short Asn-linked glycans composed of two GlcNAc residues (17). While cytosolic proteins of Giardia may contain GlcNAc linked to Ser or Thr residues, no O-linked glycans have been identified in its secreted or cyst wall proteins (18).The Entamoeba cyst wall is modeled by Entamoeba invadens, which infects reptiles but not humans, because E. histolytica does not encyst in axenic culture or in the mouse model. The Entamoeba cyst wall is composed of fibrils of ␤-1,4-linked N-acetylglucosamine (GlcNAc) (chitin), which are labeled by wheat germ agglutinin (WGA) (19,20). Entamoeba cyst walls contain three abundant chitin-binding glycoproteins (lectins) that cross-lin...

show abstract

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

Cited by 28 publications

References 38 publications

Inhibition of Giardia intestinalis by Extracellular Factors from Lactobacilli: an In Vitro Study

Inhibition of Giardia intestinalis by Extracellular Factors from Lactobacilli: an In Vitro Study

Cell Cycle Synchrony in Giardia intestinalis Cultures Achieved by Using Nocodazole and Aphidicolin

Ethanol and Isopropanol in Concentrations Present in Hand Sanitizers Sharply Reduce Excystation of Giardia and Entamoeba and Eliminate Oral Infectivity of Giardia Cysts in Gerbils

Contact Info

Product

Resources

About