摘要:

ABSTRACT.The morphology ofTrypanosoma manulisn. sp. is described from living and stained specimens obtained from the blood of a Pallas cat,Felis manul, from Kazakhstan. the cat was also infected with aHepatozoonsp. and feline immunodeficiency virus. the morphology of the trypanosome most closely resembles that ofTrypanosoma mpapuenseReichenow andTrypanosoma heybergiRodhain found in bats.Trypanosoma manulisdoes not grow well in conventional media, but co‐culture with African green monkey kidney cells in Eagle's Minimum Essential Medium supplemented with 10% fetal calf serum at approximately 27° C resulted in luxuriant growth of trypanosomes. Under these growth conditions, epimastigotes adhered to the surface of the culture flask and to African green monkey kidney cells, as well as forming large rosettes. At 37° C, although growth was poor, transformation of the epimastigotes into the bloodstream forms occurred. This represents the first report of a trypanosome of the subgenusMegatrypanumin a fe

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04908.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.A novelBabesiaparasite of desert bighorn sheep was isolated. Its taxonomic description, host range, pathogenicity and antigenic relatedness were in vestigated. the parasite was infective for black‐tailed and white‐tailed deer, but with host‐specific differences compared to that of bighorn sheep. A splenectomized calf and domestic sheep were refractory to infection. A comparative immunofluorescence assay detected antigens cross‐reactive withBabesia odocoilei, B. divergens, B. equiandB. caballi, but not withB. bovisor,B. bigemina. Babesia odocoileiwas also infective for bighorn sheep, allowing comparison by a cross‐challenge experiment, the results of which supported the conclusion that this parasite was notB. odocoilei.However, the bighorn sheepBabesiacannot currently be distinguished fromB. capreolidescribed from roe deer in northern Germany. Data indicate that, while this parasite may not present a problem for domestic animals, it may cause disease in bighorn sheep and deer po

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04909.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.The in vitro activities of a series of quassinoids againstPlasmodium falciparum, Entamoeba histolytica, Giardia intestinalis and Toxoplasma gondiihave been compared with their in vitro cytotoxic effects against KB cells (human epidermoid carcinoma of the nasopharynx). All of the compounds tested were more toxic to KB cells than toG. intestinalis, but four (ailanthinone, bruceine D, brusatol and glaucarubinone) were slightly less toxic to KB cells than toE. histolytica.Glaucarubinone was similarly more toxic to intracellularT. gondiithan to KB cells but ailanthinone was more selective (36 times more toxic toT. gondiithan to KB cells). All of the compounds were more toxic toP. falciparumthan to KB cells; the most selective quassinoids—glaucarubinone, bruceine D, ailanthinone and brusatoi—were found to have toxicity/activity ratios of 285, 76, 48 and 32 respectively. These results suggest that quassinoids have a selective action onP. falciparum.Further studies to elucidate the basis for this are in progr

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04910.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Oxygen uptake in cysts and trophozoites of the parasitic protozoanGiardia lambliawas examined. Both showed oxygen uptake activity, but that of cysts was only 10% to 20% that of trophozoites. Oxygen dependence of oxygen uptake in cysts and trophozoites showed oxygen maxima above which oxygen uptake decreased. the oxygen concentration at which the oxygen uptake rate was greatest was higher for trophozoites than for cysts. the effect of various inhibitors on cyst and trophozoithe oxygen uptake suggested that flavoproteins and quinones play some role in oxygen uptake. the substrate specificities and the effect of inhibitors onG. lambliatrophozoites were similar to those observed forG. muris.Metronidazole, the drug most commonly used in treatment of giardiasis, inhibited oxygen uptake and motility in trophozoites; however, it had no obvious effect on either oxygen uptake or excystation in cysts. Menadione, a redox cycling naphthaquinone, first stimulated, then completely inhibited, oxygen uptake in cysts and trophozoites; a complete loss of cyst viability and trophozoite motility was also observed. the effect of menadione onG. Iambliamay indicate that redox cycling compounds have potential as chemotherapeutic agents for the treatment of giardiasis.

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04911.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Free‐living soil amoebae consume a wide variety of food, including algae, yeast, small protozoa and especially bacteria, which they digest to fulfil their nutritional requirements. Amoebae play an active role in the nitrogen mineralization in soils due to their nitrogen metabolizing capacities. However, little is known about nitrogen metabolizing enzyme activities in these free‐living soil amoebae. In this study a number of key enzymes involved in the nitrogen metabolism of the axeaically cultivated free‐living soil amoebaeAcanthamoeba castellanii, Acanthamoeba polyphagaand two different strains ofHartmannella vermiformiswere determined. the specific enzyme activities for exponential growth phase ceils were calculated and it appeared that the species tested possessed urate oxidase, glutamine synthetase, NADH‐dependent glutamate dehydrogenase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activity. Glutamate synthase activity could not be detected in any of these species. the levels of specific activities varied depending on the enzymes tested. For all species the highest activities were detected for the transaminase reactions yielding glutamate, and for glutamate dehydrogenase. A general conclusion is that the pathway of nitrogen assimilation in free‐living soil amoebae is similar to the one observed for other eukaryotes. Differences in specific activities were detected between th

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04912.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.The quantitative protargol stain (QPS) is used to estimate ciliate biomass and species composition from mixed field samples. Length, width, breadth and volume of liveEuplotessp.,Eutintinnussp.,Strobilidium spiralis, Strombidium acutum, andGymnodinium sanguineumwere compared with 0.6% acid Lugol's fixed, 5% Bouin's fixed, and QPS cells. Cells shrank due to treatments (ANOVA and Tukey's test, α= 0.05). Protistan post‐fixation cell volume (as a percentage of live volume) was 55%‐80% for acid Lugol's fixed, 40%‐70% for Bouin's fixed, and 30%‐65% for QPS. Each species shrank to a different extent; cytostructural elements apparently alter the effect of fixation. Egestion is likely not the main cause of shrinkage since the autotroph,G. sanguineum, shrank to the same extent as the heterotrophs when stained by QPS. If field studies do not consider fixation effects on cell size, biomass may be underestimated. We recommend, for studies on planktonic ciliates, either acid Lugol's and QPS be used concurrently or QPS be used alone and biovolume values divided by 0.4 to correct for shrinkage. We stress that this is a rough estimate as this value ranges from 0.3 to 0.45 for planktonic

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04913.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Two derivatives of the mesoionic thiazolo[3,2‐a]pyrimidine‐5,7‐diones1were prepared and examined for in vivo antiprotozoan activity to study structure‐activity relationships that might lead us to more active derivatives. Mesoionic compounds 1A and 1B were inoculated into Swiss Webster male mice withTrypanosoma musculiinfection. the effects were measured by studying parasite populations during the course of patent period (days 9 through 15 post‐infection).The injection of 200 μg of compound 1A along with 5 times 104trypanosomes affected the level of parasitemia at both the peak and during days 9 to 13 post infection. Experimental animals that received drug 1A prior to and after infection withT. musculideveloped significantly lower parasitemia as compared to the control animals at the height of parasite populations (day 11 of observation). the group that received the drug simultaneously with trypanosome infection had significantly lower parasitemias on day 11 and 13 of infection compared to th

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04914.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Resitance to metronidazole detectable under anaerobic conditions was induced in twoTrichomonas vaginalisstrains (TV 10‐02 and MRP‐2) by cultivation at gradually increasing pressure of the drug (1‐100 μ/ml) for 12 to 21 months. the resistant derivatives reproduced in anaerobic trypticase‐yeast‐extract‐maltose medium at 100 μ/ml metronidazole and showed very high values of minimal lethal concentration for metronidazole in anaerobic in vitro assays (556‐1,600 μ/ml at 48‐h exposure to the drug). Stepwise selection was necessary to develop the resistance in either strain. Attempts to induce resistance by prolonged maintenance of trichomonads with constant, low or moderate drug concentrations (3‐10 μ/ml) were unsuccessful. Freshly developed resistance to high concentrations of metronidazole was unstable in absence of drug pressure as well as after cryopreservation. Development of stable resistance required further cultivation at 100 μ/ml metronidazole. Unstable substrains did not revert to original susceptibility. They retained a moderate level of resistance, being able to grow at 10 μ/ml metronidazole. the strains with fully developed resistance had no activity of the hydrogenosomal enzymes pyruvate: ferredoxin oxidoreductase and hydrogenase and ceased uptake of [14C]‐metronidazole. These findings indicate that the pyruvate oxidizing pathway responsible for metronidazole activation was inactivated and metab

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04915.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Using transmission electron microscopy, transverse dense bands were found to be associated with subpellicular microtubules and inner membraner inPlasmodium falciparumgametocytes. These dense bands may act as supportive structures to maintain the parallel arrangement of the microtubules, and/or to connect them to the inner membranes.

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04916.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Thirty four taxa of heterotrophic protists (amoebae, flagellates and heliozoa) were encountered in cultures established from marine samples from Belize (Central America) and Tenerife (Canary Islands). Most species are flagellates drawn from the choanoflagellates, the cryptophyceans, the euglenids, the kinetoplastids, the bicosoecids, the chromulinids, the pedinellids and a variety of laxa of uncertain affinities (Protista incertae sedis). the identity of the thecate choanoflagellatesSalpingoeca ringensKent, 1880, andS. tubaKent, 1880, is discussed, and four new species of heterotrophic protists are described: one new species of the amoeba genusPaulinella (Paulinella intermedian. sp.) and three new species of the incertae sedis genusLuffisphaeraBelcher&Swale, 1975 (Luffisphaera bulbochaeten. sp.;L. longihastisn. sp.;L. turriformisn. sp.).

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04917.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY