Protein synthesis in a cell-free preparation from rumen Protozoa.
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Adenosine Triphosphate↗
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Partial purification and some properties of glucose 6-phosphate dehydrogenase from Eimeria stiedai (Lindemann, 1865) Kisskalt & Hartmann, 1907 (Protozoa: Coccidia).
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Animals↗
Further studies on the properties of glucose 6-phosphate dehydrogenase from the coccidium Eimeria stiedai (Protozoa).
1. Glucose 6-phosphate dehydrogenase from Eimeria stiedai does not reduce NAD or any of its analogs tested. It does reduce NADP and its thionicotinamide and 3-acetylpyridine analogs. 2. It will accept D-glucose as substrate, but not 2-deoxy-D-glucose, glucose 1-phosphate, or 2-deoxy-D-glucose 6-phosphate. 3. Its response to a number of compounds that activate or inhibit the enzyme from other organisms has been determined. 4. The molecular weight is ca. 240,000 by gel chromatography, and only one isoenzyme could be detected by disc electrophoresis. 5. The enzyme resists conditions that commonly cause dissociation to lighter weight active forms.
Animals↗
Purine phosphoribosyltransferases of Leishmania mexicana mexicana and other flagellate protozoa.
Amastigotes and cultured promastigotes of Leishmania mexicana mexicana and L. m. amazonensis, cultured promastigotes of L. donovani and L. tarentolae, and the culture forms of Crithidia fasciculata, Herpetomonas muscarum muscarum and H. m. ingenoplastis all possessed four phosphoribosyltransferase (PRTase) activities: adenine PRTase, hypoxanthine PRTase, guanine PRTase and xanthine PRTase. The enzymes of L. m. mexicana required divalent cations for activity; Mn2+ or Co2+ produced maximal activity in most cases. Hypoxanthine PRTase, guanine PRTase and xanthine PRTase from all organisms were sedimentable in part, suggesting that they may occur within glycosomes. The enzymes of L. m. mexicana cultured promastigotes were inhibited by a range of purine analogues.
Adenine Phosphoribosyltransferase↗
Ca2+-binding modulator protein in protozoa and myxomycete.
Ca2+-binding protein with the properties of brain modulator protein of 3,5-cyclic nucleotide phosphodiesterase was identified in Physarum polycephalum plasmodia and in Euglena gracilis and Amoeba proteus cells by urea polyacrylamide gel electrophoresis and activation of cyclic nucleotide phosphodiesterase and of myosin light chain kinase.
2',3'-Cyclic-Nucleotide Phosphodiesterases↗
[Active antihelminitic alkaloids: active in vitro against Leishmanic Tropica the protozoa involved in leishmaniasis].
Leishmaniasis caused by protozoan Leishmania ssp., is an endemic parasitic disease in Central and South America. The chemotherapeutic agents against Leishmania ssp. (pentavalent antimony compounds, pentamidine and amphothericine B) are toxic and expensive products. Basing on the Bolivian folk medicine, we tried to find new active principles. Fourteen isoquinoline alkaloids, especially bisbenzylisoquinoline alkaloids extracted from Annonaceae, Berberidaceae, Hernandiaceae and Menispermaceae, demonstrate highly effective activity against this protozoan. Among them gyrocarpine, daphnandrine and obaberine seem to be of particular interest. The therapeutic effect was studied by biological assays on culture forms in vitro three strains of Leishmania, L. donovani, L. braziliensis (cutaneous and mucocutaneous leishmaniasis), L. mexicana amazonensis (cutaneous) and L. donovani (visceral leishmaniasis).
Alkaloids↗
Application of knockout mice to the experimental analysis of infections with bacteria and protozoa.
Knockout mice with distinct gene deletions are valuable tools for in vivo analyses of the immune response against infectious agents. Studies of bacterial and protozoal infections have shown that antimicrobial immunity is generally defective in knockout mice. At one extreme, deletion of just one gene may completely compromise resistance, while at the other extreme, redundancy in the immune system allows partial compensation for the deleted part.
Animals↗
DNA topoisomerase I from parasitic protozoa: a potential target for chemotherapy.
The growing occurrence of drug resistant strains of unicellular prokaryotic parasites, along with insecticide-resistant vectors, are the factors contributing to the increased prevalence of tropical diseases in underdeveloped and developing countries, where they are endemic. Malaria, cryptosporidiosis, African and American trypanosomiasis and leishmaniasis threaten human beings, both for the high mortality rates involved and the economic loss resulting from morbidity. Due to the fact that effective immunoprophylaxis is not available at present; preventive sanitary measures and pharmacological approaches are the only sources to control the undesirable effects of such diseases. Current anti-parasitic chemotherapy is expensive, has undesirable side effects or, in many patients, is only marginally effective. Under this point of view molecular biology techniques and drug discovery must walk together in order to find new targets for chemotherapy intervention. The identification of DNA topoisomerases as a promising drug target is based on the clinical success of camptothecin derivatives as anticancer agents. The recent detection of substantial differences between trypanosome and leishmania DNA topoisomerase IB with respect to their homologues in mammals has provided a new lead in the study of the structural determinants that can be effectively targeted. The present report is an up to date review of the new findings on type IB DNA topoisomerase in unicellular parasites and the role of these enzymes as targets for therapeutic agents.
Animals↗
Biphenylquinuclidines as inhibitors of squalene synthase and growth of parasitic protozoa.
In this paper we describe the preparation of some biphenylquinuclidine derivatives and their evaluation as inhibitors of squalene synthase in order to explore their potential in the treatment of the parasitic diseases leishmaniasis and Chagas disease. The compounds were screened against recombinant Leishmania major squalene synthase and against Leishmania mexicana promastigotes, Leishmania donovani intracellular amastigotes and Trypanosoma cruzi intracellular amastigotes. Compounds that inhibited the enzyme, also reduced the levels of steroids and caused growth inhibition of L. mexicana promastigotes. However there was a lower correlation between inhibition of the enzyme and growth inhibition of the intracellular parasites, possibly due to delivery problems. Some compounds also showed growth inhibition of T. brucei rhodesiense trypomastigotes, although in this case alternative modes of action other than inhibition of SQS are probably involved.
Animals↗
More than one way to build a flagellum: comparative genomics of parasitic protozoa.
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Animals↗
A new soil hypotrich ciliate (Protozoa, Ciliophora) from Slovakia: Gonostomum albicarpathicum nov. spec.
The morphology and infraciliature of the soil hypotrich ciliate, Gonostomum albicarpathicum nov. spec., collected from Biele Karpaty (White Carpathian Mts.), Slovakia, were investigated using living observations and the protargol impregnation method. This new species is distinguished from its congeners by a combination of characters including arrangement of macronuclear nodules forming a pair of nodules each ahead of and behind mid-body; 6-10 frontoventral cirri and 3 frontoterminal cirri forming a short row; first frontoterminal cirrus separated from the second by a slightly greater distance than between second and third.
Animals↗
Trypanosomatid protozoa: a simplified DNA isolation procedure.
A non-toxic and versatile protein salting-out DNA extraction method is here described for convenient and rapid extraction of nuclear DNA molecules from trypanosomatids. The procedure just involves four manipulations, does not require any organic solvent, and is performed in less than 1h in a single tube. DNA yields obtained were similar to those from commercial kits and phenol-chloroform procedures. Samples extracted by this method were suitable for PCR and subsequent analyses. The reduced manual labour involved was perceived as an important benefit in medical diagnosis routine use as well as for large-scale taxonomic and eco-epidemiological studies of trypanosomatids.
Animals↗
Redescription of Besnoitia tarandi (Protozoa: Apicomplexa) from the reindeer (Rangifer tarandus).
Besnoitia tarandi tissue cysts were found in naturally-infected reindeer (Rangifer tarandus) from Finland. Infectivity of its tissue cysts, bradyzoites, and tachyzoites to animals and cell culture was studied. The bradyzoites and tissue cysts were not infectious to out-bred mice, rabbits or gerbils. When fed tissue cysts, neither cats nor dogs excreted oocysts. However, the parasite was lethal to interferon-gamma gene knock out mice irrespective of the route of inoculation. The parasite was grown successfully in African Green Monkey cells from tissues of two reindeer for the first time. Non-dividing, uninucleate tachyzoites from smears from cell cultures were 5.6 x 1.4 microm (4.5-7.4 x 1.0-1.9, n=50) in size. Longitudinally-cut bradyzoites in tissue sections measured 7.4 x 1.3 microm (6.5-7.8 x 1.0-1.6, n=30). Ultrastructurally, tachyzoites and bradyzoites were similar to those in other Besnoitia species, and in particular to parasites described from cattle (Besnoitia besnoiti) and equids (Besnoitia bennetti) in that their bradyzoites lacked enigmatic bodies. Based on comparative analysis of three portions of nuclear ribosomal DNA (the small and large subunits and the first internal transcribed spacer) B. tarandi was found to be more closely related to the other congeners described from ungulates. The parasite was formally redescribed and specimens deposited in the US National Parasite Collection.
Animals↗
Redescription of Besnoitia bennetti (Protozoa: Apicomplexa) from the donkey (Equus asinus).
Besnoitia bennetti tissue cysts were found in four naturally-infected donkeys (Equus asinus) from the USA. Infectivity of its bradyzoites and tachyzoites to animals and cell culture was studied. The bradyzoites were not infectious to out-bred Swiss Webster mice, rabbits or gerbils. When fed tissue cysts, cats did not excrete oocysts. However, the parasite was infectious to interferon-gamma gene knock out mice. The parasite from tissues of two donkeys was grown successfully in bovine monocyte monolayers for the first time. Non-dividing, uninucleate tachyzoites were approximately 6 x 1.5 microm in size. Longitudinally-cut bradyzoites in tissue sections measured 8.7 x 1.9 microm. Ultrastructurally, tachyzoites and bradyzoites were similar to those in other Besnoitia species, and in particular to parasites described from cattle (Besnoitia besnoiti) and reindeer (Besnoitia tarandi), in that their bradyzoites lacked enigmatic bodies. Based on comparative analysis of three portions of nuclear ribosomal DNA (the small and large subunits and the first internal transcribed spacer) B. bennetti was found to be more closely related to the other congeners described from ungulates. The parasite was formally redescribed and specimens deposited in the US National Parasite Collections.
Animals↗
Irritable bowel syndrome: a review on the role of intestinal protozoa and the importance of their detection and diagnosis.
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder in which abdominal pain is associated with a defect or a change in bowel habits. Gut inflammation is one of the proposed mechanisms of pathogenesis. Recent studies have described a possible role for protozoan parasites, such as Blastocystis hominis and Dientamoeba fragilis, in the etiology of IBS. Dientamoeba fragilis is known to cause IBS-like symptoms and has a propensity to cause chronic infections but its diagnosis relies on microscopy of stained smears, which many laboratories do not perform, thereby leading to the misdiagnosis of dientamoebiasis as IBS. The role of B. hominis as an etiological agent of IBS is inconclusive, due to contradictory reports and the controversial nature of B. hominis as a human pathogen. Although Entamoeba histolytica infections occur predominately in developing regions of the world, clinical diagnosis of amebiasis is often difficult because symptoms of patients with IBS may closely mimic those patients with non-dysenteric amoebic colitis. Clinical manifestations of Giardia intestinalis infection also vary from asymptomatic carriage to acute and chronic diarrhoea with abdominal pain. These IBS-like symptoms can be continuous, intermittent, sporadic or recurrent, sometimes lasting years without correct diagnosis. It is essential that all patients with IBS undergo routine parasitological investigations in order to rule out the presence of protozoan parasites as the causative agents of the clinical signs.
Animals↗
The effects of extracts from anti-diarrheic Thai medicinal plants on the in vitro growth of the intestinal protozoa parasite: Blastocystis hominis.
The activities of n-hexane, dichloromethane and methanol extracts from five anti-diarrheic Thai medicinal plants, Acacia catechu (Fabaceae) resin, Amaranthus spinosus (Amaranthaceae) whole plant, Brucea javanica (Simaroubaceae) seed, Piper longum (Piperaceae) fruit and Quercus infectoria (Fagaceae) nut gall were tested against the in vitro growth of fresh isolates of the intestinal protozoan parasite, Blastocystis hominis. The extracts at concentrations that ranged from 62.5 to 2000 microg/mL, were incubated with several isolates of Blastocystis hominis for 48 h. The activities were classified as killed, inhibited, moderately inhibited and not-inhibited. Dichloromethane and methanol extracts from the Brucea javanica seed and a methanol extract from Quercus infectoria nut gall showed the highest activity. At a concentration of 2000 microg/mL, the three extracts killed 82, 75 and 67% of the Blastocystis hominis samples tested and inhibited 94, 100 and 76% of them, respectively. Metronidazole, used as a reference antiprotozoan drug, at a concentration of 40 microg/mL, killed 97% of the Blastocystis hominis isolates and inhibited all samples tested at concentrations that ranged from 1.25 to 20 microg/mL.
Animals↗