ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05887.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT.Giardia lambliatrophozoites express on their surfaces one of a set of cysteine‐rich antigenically variant proteins, called variant‐specific surface proteins, which comprise the majority of proteins detected by surface labeling. While these VSP proteins may be immunodominant proteins important in the host immune response toG. lamblia, the ability to switch expression from one VSP to another may provide a means for the trophozoites to avoid the host immune response. The first VSP characterized, VSPA6 (from the A6 clone of the WB isolate, originally termed CRP170), contains 18–23 copies of a 65 amino acid repeat. We have now used the repeat as a probe to isolate from a WBA6 genomic library two genes related to vspA6 (called vspA6‐S1, vspA6‐S2). Sequence analysis of the vspA6‐S1 gene revealed nearly two complete copies of the 195 bp repeat and substantial nucleotide and translated amino acid similarity in the coding regions 5’and 3’to the repeats. The vspA6‐S2 gene, while still related, showed greater divergence from vspA6 than vspA6‐S1 in the nonrepeat coding region and contained nearly four copies of a 201 bp repeat that was 75% identical to the 195 bp vspA6 repeat. These results suggest that gene duplication followed by divergence has played a key role in the generation of the

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05888.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT.Microsporidia of the genusEncephalitozoonundergo merogony and sporogony in a parasitophorous vacuole within the host cell. Cultured green monkey kidney cells infected withEncephalitozoon hellemwere loaded with the fluorescent dyes fura‐2 or BCECF in order to measure intracellular concentrations of calcium and hydrogen ions respectively. Both the parasitophorous vacuole calcium concentration and pH values resembled those of the host cell cytoplasm in infected cells. Calcein entered the parasitophorous vacuole but not other host cell vacuoles or parasite stages within the parasitophorous vacuole. The lack of a pH or calcium concentration gradient across the parasitophorous vacuole membrane and the permeability of this membrane to a large anion such as calcein suggest that the vacuole membrane surroundingE. hellemresembles that surrounding some other intracellular parasites such asToxoplasma gondii.A potential role is discussed for the parasitophorous vacuole calcium concentration in germination in sit

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05889.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT.Experimental transmission of two bacterial endosymbionts to symbiont‐free isolates ofAcanthamoebaspp. was studied to determine specificity of the host‐symbiont relationship. Both symbionts originated from amoebic isolates displaying an identical mitochondrial DNAEcoRI fingerprint (group AcUW II). Symbioses were readily established in one amoebic isolate which displayed a homologous mtDNA fingerprint (group AcUW II). Exposure of a heterologous amoebic isolate (group AcUW IV) to the two symbionts resulted in either cell death or encystation without the establishment of symbioses. While symbioses were established with an amoebic isolate from a second heterologous group (AcUW I), a unique membranous sheath appeared and persisted around one of the symbionts which did not exist in the original host. An isolate representing a third heterologous amoebic group (AcUW VI) was variable in its susceptibility with one symbiont unable to infect the host and the other becoming established only after an initial reaction in which trophozoites rounded‐up and floated off the substrate. These studies suggest that a specific recognition system exists between particular isolates ofAcanthamoebaand their symbionts, and that the appearance of a killer phenotype is related to contact between mismatched, though recognized,

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05890.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT.The order Euplotida represents a monophyletic order of five families of hypotrich ciliates united by morphology, stomatogenesis, ultrastructure, cyst structure, and behavior. A review of variability of ciliation and nuclei among the 14 genera suggests that lines of evolution may have involved both the loss of cirri and nuclear simplification. We present a binary key to genera in the families Aspidiscidae (AspidiscaandEuplotaspis), Certesiidae n. fam. (Certesia), Gastrocirrhidae (Cytharoides, Euplotidium, andGas‐trocirrhus), Uronychiidae (Diophryopsis, Diophrys, Paradiophrys, andUronychia), and Euplotidae. The latter family contains species formerly in the genusEuplotes.Based primarily on cortical structure, endosymbionts, data from morphometric analysis, and ecology, we recognize four different groups. The first group of species remains inEuploteswithEuplotes charonas type. We place a second group of species into the genusMoneuplotesJankowski 1979 withMoneuplotes vannus(Müller, 1786) as type. We erect two new genera:Euplotoidesn. g. andEuplotopsisn. g. withEuplotoides patella(Müller, 1773) n. comb. andEuplotopsis affinis(Dujardin, 1841) n. comb. as type species respectively. We discuss possible phylogenetic relationships within the or

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05891.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT.The glycerophosphate oxidase (GPO), the unique terminal oxidase of bloodstream trypanosome (TAO), appears to be functionally similar to the alternative oxidases of some plants and higher fungi. Immunoblotting of mitochondrial proteins of bloodstream trypomastigotes ofTrypanosoma brucei bruceiwith monoclonal or polyclonal antibodies toSauromatum guttatum(voodoo lily) andSymplocarpus foetidus(skunk cabbage) alternative oxidases respectively revealed two proteins of about 33 kDa (p33) and 68 kDa (p68). These proteins are not present in procyclic trypomastigotes. Electrophoresis under rigorous denaturing conditions indicated p68 to be the dimer of p33. Indirect immunofluorescent studies of bloodstream and procyclic trypomastigotes with monoclonal antibody to plant alternative oxidase also showed the localization of 33 kDa protein in the mitochondria of the bloodstream trypomastigotes. The functional TAO activity could be solubilized efficiently from the mitochondrial membrane of the bloodstream trypomastigotes by 1% NP‐40 or 10 mM lauryl maltoside. When fractionated by Superose 12 gel filtration chromatography, p33 was co‐purified with the TAO enzymatic activity. The apparent molecular size of the active enzyme complex was found to be 160 kDa. Gradual disappearance of the 33 kDa protein and the TAO enzymatic activity were well correlated during in vitro differentiation of the bloodstream to procyclic trypomastigotes. This study implies that the net biosynthesis of p33, an essential subunit of TAO, is decreased during differentiation from bloodstream to procyclic trypomastigo

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05892.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT.We compared the expression and localization of the mitochondrial and cytoplasmic hsp70 of the protozoansTrypanosoma cruzi, Trypanosoma bruceiandLeishmania major.The mitochondrial protein is encoded by multiple mRNA in all species, while the cytoplasmic protein is encoded by a single mRNA. In all three species, the mitochondrial hsp70 is concentrated in the kinetoplast, a submitochondrial structure that houses the unusual DNA (kDNA) that characterizes this group of organisms, while the cytoplasmic protein is distributed throughout the cell. These results suggest that, in all kinetoplastid species, mt‐hsp70 has a specific function in kDNA biology, possibly in the processes of kDNA replication, RNA editing or kinetoplast structur

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05893.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT.The morphology and infraciliature ofSiroloxophyllum utriculariae(Penard, 1922) n. g., n. comb. were studied in live cells, with the scanning and transmission electron microscope, as well as in specimens impregnated with protargol and silver carbonate. The new genus,Siroloxophyllum, belongs to the Loxophyllidae and has a specific combination of characters, viz. an oral bulge surrounding almost the entire cell, three perioral kineties, a single brush kinety, and a single right dorsolateral kinety. The ecology and faunistics ofS. utriculariaeare reviewed. It is a rare and infrequent predator preferring clean freshwaters. The somatic monokinetid ofS. utriculariaehas typical haptorid ultrastructure, including two transverse microtubular ribbons. The oral bulge is patterned string‐like with riffles containing the transverse microtubular ribbons originating from the oral kinetids. Perioral kineties 1 and 2 consist of dikinetids having one basal body each ciliated; the nonciliated basal body is associated with a nematodesmal and a transverse microtubular ribbon. Perioral kinety 3 consists of ciliated monokinetids having a fine structure similar to the somatic kinetids; they form triads with the dikinetids from perioral kinety 2. The classification of pleurostomatid ciliates is reviewed. Two suborders (Amphileptina, Litonotina) and three families (Amphileptidae, Litonotidae, Loxophyllidae n. fam.) are recognized and define

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05894.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT.The ultrastructure of two species ofHolomastigotoidesis presented. The basic unit of organization of these large cells is the flagellar band. Each flagellar band consists of a row of flagellar basal bodies linked by three fiber systems. The number of flagellar bands is species dependent. The flagellar bands originate at the cell apex and are arranged in parallel spirals of increasing gyre, thus defining the conical shape of the cell. In the cell apex a striated root called a parabasal fiber is juxtaposed with the basal bodies of each flagellar band. Linear extensions of two parabasal fibers function as the spindle poles for the persistent extra‐nuclear spindle. The nucleus is in close contact with the spindle poles and spindle microtubules. Parallel sheets of microtubules which constitute axostyles are nucleated along the underside of the parabasal fibers. The axostyles extend away from the cell apex, with many reaching the basal region of the cell. Some of the axostyles follow the spiral pattern of the flagellar bands. Numerous Golgi bodies are spaced regularly along the flagellar bands. Together the parabasal fiber, axostyles and Golgi bodies associated with a flagellar band are termed a parabasal comple

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05895.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT.The microsporidium,Enterocytozoon bieneusi, causes a severe, debilitating, chronic diarrhea in patients with the acquired immunodeficiency syndrome. Specific diagnosis of intestinal microsporidiosis, especially due toEnterocytozoon, is difficult and there is no known therapy that can completely eradicate this parasite. Preliminary studies indicate that a short term (about 6 months) in vitro culture of this parasite yielding low numbers of spores, may be established by inoculating human lung fibroblasts and/or monkey kidney cell cultures with duodenal aspirates and or biopsy from infected patients. The cultures may subsequently be used for the isolation and molecular analysis of parasite DNA.

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1995.tb05896.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY