摘要:

ABSTRACT.Cultivation of thePlasmodium gallinaceumexoerythrocytic forms from sporozoites was attempted in three diferent cell lines: HEPG2‐A16 (from a human hepatoma), VERO (monkey kidney epithelial cells) and SL‐29 (chicken embryo fibroblast cells). the sporozoites in vaded all three cell types but their development into exoerythrocytic forms ocurred only in the SL‐29 cells. In the presence of specific monoclonal antibodies against the major circumsporozoite protein, there were varying degrees of inhibition of parasite invasion of the SL‐29 cells. of seven monoclonal antibodies tested, two completely inhibited cell invasion at high concentrations and caused intense inhibition at concentrations as low as 2.5 μg/ml, four caused intense inhibition at these various concentrations, and one had no effect on sporozoite

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04883.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Scanning electron microscopic observations of feeding plasmodia show three characteristic features: 1) extension of multilobed pseudopodia protruding from the leading edge of the plasmodium as it advances onto the surface of a food particle, 2) confluence of the lobes to form a sheath‐like pseudopodium attached to the surface of the food particle, and 3) protrusion of small nodules with thin lamellar projections from the leading edge of the plasmodium. Sections through freeze‐dried preparations of the feeding plasmodium exhibit a highly convoluted under surface in contact with loosened starch grains that appear to be released by extracellular digestion. the cytoplasm, viewed by transmission electron microscopy, contains branched, internally penetrating canals (ca. 2 μm wide) enclosing engulfed starch grains. Starch grains in the deeper part of the canals are more electron dense and appear to be digested. Micropseudopodia (70‐80 nm dia.), projecting from the surface of the canals, protrude toward and into the ingested starch grains. Digestive marker enzyme (acid phosphatase) activity was detected cytochemically in food particles penetrated by micropseu‐dopodia indicating a digestive role for these structures not reported pr

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04884.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Presporogonic (blood) stages ofSphaerospora epinepheliSupamattaya, Fischer‐Scherl. Hoffmann, Boonyaratpalin, 1990 were observed in the circulating blood, sinus of kidney, glomerurar capillaries and liver arteries of grouperEpinephelus malabaricus.the earliest detectable stage was a primary cell with one secondary cell. After cell divisions, nine to 16 secondary cells were found in one primary cell. Ultrastructural examination revealed electron‐dense bodies (118‐145 nm) in the cytoplasm of primary cells. Sporogonic stages and spores were located in Bowman's space and in kidney tubule lumens. Electron micrographs revealed a similar pattern of spore development as described from other Sphaerospora spp. Kidneys infected withS. epinephelishowed highly vacuolated tubular epithelial cells and severely affected renal corpu

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04885.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Ejectable trichocysts were isolated from the ciliatePseudomicrothorax dubius.Polyclonal antibodies were raised against three groups of trichocyst proteins: G1 (30‐31 kDa), G2 (26‐27 kDa) and G3 (15‐20 kDa). By indirect immunofluorescence, the three antisera strongly label the shafts of ejected trichocysts and the proximal ends of condensed trichocysts within the cells. By immunogold labeling for electron microscopy, the three sera specifically recognize the shafts of both extended and condensed trichocysts and shaft precursors in pretrichocysts as well. On one‐dimensional immunoblots of isolated trichocysts, anti‐G1 serum recognizes the G1 proteins, anti‐G2 serum detects G2 proteins and some G1 proteins, and anti‐G3 serum reacts with 15 bands, mainly the G3 and (30‐41)‐kDa proteins. In cells with and without trichocysts, the sera recognize non‐ejectable trichocyst proteins at 41‐42 kDa and 47 kDa. On two‐dimensional immunoblots of isolated trichocysts, anti‐G1 serum labels proteins with a pI of 4.75‐5.7, anti‐G2 serum labels proteins with a pI of 4.75‐6.25 and anti‐G3 serum labels proteins with a pI of 4.7‐6.6. Analyses of cells with and without trichocysts allow identification of possible precursors between 41 and 47 kDa. Some are in the same pI range as their putative products, but others, labeled by anti‐G3 serum, are less acid

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04886.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.The unusual nature of mitosis and ancestral organization of the dinoflagellate nucleus prompted the question of whether thecdc2‐like histone H1 kinase, a presumed ubiquitous cell cycle regulator in eukaryotes, is present in these primitive organisms. Western blotting ofCrypthecodinium cohniiprotein extracts using antibody against the Pro‐Ser‐Thr‐Ala‐Ile‐Arg‐Glu (=PSTAIRE) amino acid sequence motif, conserved in allcdc2 homologues known, revealed one prominent band corresponding to a protein with an apparent relative molecular weight ≈ 34,000, identical in mobility to that from HeLa cells andPhysarum polycephalum, higher and lower eukaryotic controls, respectively. Incubation ofC. cohniicell lysates with p13suc1‐sepharose beads, which preferentially, though not exclusively, bind p34cdc2, resulted in precipitation of a 34‐kDa protein which was reactive with anti‐PSTAIRE antibody, selectively competed for by the PSTAIRE peptide and able to phosphorylate histone H1 in vitro. We conclude that the dinoflagellateC. cohniicontains a protein very similar to thecdc2 gene product from fission yeast and its homologues in all eukary

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04887.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Fossil protist cysts are reported from the mid‐Cretaceous amber of Ellsworth County, Kansas, which is rich in terrestrial microfossils but contains no known macrofossils. On the basis of their distinctive morphology, the cysts can be referred to the genusNaegleria(Schizopyrenida); they most closely resemble cysts of the living speciesNaegleria gruberi.This is the first known fossil record for this group of amoebas. the current phylogenetic position and paleoecological role ofNaegleriaare discussed in relation to this find; it provides direct confirmation of morphological stasis in this group, which had previously been inferred from rRNA sequence divergence data

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04888.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Intestinal microsporidiosis in patients diagnosed with acquired immunodeficiency syndrome (AIDS) and having chronic diarrhea was first reported in 1985 and the associated microsporidian was namedEnterocytozoon bieneusi.the intracellular developmental cycle ofE. bieneusiin enterocytes has been demonstrated and many cases have been reported worldwide. This report presents the life cycle of a second intestinal microsporidian, associated with the same symptoms, in five AIDS patients. This new microsporidian also infects enterocytes but its pathology and morphology differ from that ofE. bieneusi.It involves lamina propria macrophages, fibroblasts, and endothelial cells and can disseminate to infect other parts of the body, e.g. the kidney and gall bladder. the parasite cycle includes development of rounded uninucleate and elongated bi‐ or tetranucleate cells without the formation of plasmodial stages. Sporogony is similar to the more typical development of microsporidia with sporoblast morphogenesis occurring after the last cell division. the development of cells within chambers of a septate, honeycomb‐like, parasite‐secreted fibrillar network and surrounded by a parasitophorous vacuole, however, is unique to this microsporidian, justifying the establishment of a new genus and species,Septata intestinalisn. g.,

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04889.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb04890.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY