摘要:

RÉSUMÉL'étude, par le protargol, des phénomènes infraciliaires et de leur corrélation avec les phénomènes nucléaires au cours de l'autogamie dans le genreEuplotesmontre, par comparaison avec la conjugaison, que les diverses étapes de la morphogenèse sont liées à la progression de l'état nucléaire. Par ailleurs, l'étude comparative des différents types de morphogenèse (bipartition, phénomena sexuel, réorganisation induite par le jeǔne) permet de supposer qu'il existe deux territoires morphogènes soumis à des systèmes de régulation bien distincts. La comparaison des séquences de morphogenèse chez divers hypotriches conduit à dresser un plan général d'évolution de la régulation de l'activité corticale en relation avec l'étendue des remaniements associés à la stomatogenèse.ABSTRACTThe changes in the arrangement of the infraciliature associated with autogamy inEuplotesare described and compared with similar events associated with conjugation. The successive steps of morphogenesis are strongly correlated with nuclear processes. The comparative study of different types of morphogenesis (binary fission, sexual phenomena, starvation‐induced reorganization) leads to the hypothesis that two morphogenetic fields (a ventral one and a dorsal one) depend on separate regulatory systems. From the viewpoint of evolution, the morphogenetic sequences of some hypotrichs have been compared. A general scheme of the evolution of cortical regulation is proposed, taking into account the extension of the are

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02852.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThree species ofPseudocohnilembuswere examined with respect to infraciliature and the silverline system. The freshwater speciesP. putrinusandP. pusillusexhibited no differences in general organization of the argyrophilic structures when compared with the marineP. marinus.A review of thePseudocohnilembusspecies that have been described on the basis of silver preparations shows that at present four species have been well characterized:P. pusillus(Quennerstedt, 1869) nov. comb.,P. putrinus(Kahl, 1928) nov. comb.,P. hargisiEvans&Thompson, 1964, andP. marinusThompson, 1966,P. persalinusEvans&Thompson, 1964 andP. longisetaEvans&Thompson, 1964 are regarded as identical with the older knownP. pusillus, because with respect to morphology and argyrophilic structures they are within the range of variability of that species; and their names thus fall as synonyms ofP. pusillus.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02853.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTElectron microscopy was used to examine the flagellar apparatus ofHerpetomonas ampelophilaefrom the gut and malpighian tubules ofDrosophila melanogaster. The flagellates attach to the microvilli either by weaving their flagella between the microvilli or by engulfing several microvilli with an external flagellar membrane. The first type predominated in the gut while the second type was limited to the malpighian tubules. Desmosomes were not involved in either type of attachment. A subpellicular collar with emerging microtubules was found to be adjacent to the desmosome of the flagellar pocket of herpetomonads in the gut.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02854.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTFathead minnows,Pimephales promelas, raised from eggs in the laboratory, were experimentally infected with oocysts ofEimeria iroquoinafrom eitherP. promelasor the common shiner,Notropis cornutus. Within intestinal epithelial cells, trophozoites thought to be derived from the sporozoites contained a prominent electron‐dense refractile body. Merozoites dedifferentiated into trophic forms by losing components of their apical complex and pellicle. The inner membrane components of the pellicle appeared discontinuous, and the micronemes became enclosed within vacuoles. Prior to merozoite formation, multinucleate meronts were limited by a single membrane. Golgi complexes were associated with the nuclei of this stage. Merozoites were formed by ectomerogony in one generation and by endomerogony in the final generation. In both forms of merogony the final nuclear division was coupled with the onset of differentiation of the merozoites and featured eccentric mitotic spindles associated with centrocones located within the nuclear envelope and with the precursors of the apical complex. A Golgi complex was closely associated with the nucleus and apical tip of the forming merozoite. Unlike otherEimeriaspecies, the complete pellicle of the merozoites of the final asexual generation ofE. iroquoinawas formed within the cytoplasm of the meront, without association with the limiting membrane, thus, all pellicular components are synthesized de novo. The inner membranes of the pellicle initially appeared as longitudinal strips, each of which was associated with a pair of the 22–24 subpellicular microtubules. Mature meronts of the final asexual generation averaged 9 μm in diameter and produced 13–16 merozoites. With the exception of the internal completion of the pellicle of the final generation merozoites, the basic processes of merogony in fishEimeriaspecies are similar to those recorded in terrestrial

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02855.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTProrocentrum micansEhrenberg, a free‐living marine dinoflagellate, was used to test the intracellular toxic action of cadmium. The cells were cultivated in Erdschreiber medium, with Cd concentrations of 10–100 ppb. Thin sections of treated cells, examined ultramicroscopically, exhibited vacuolations, increased numbers of lysosomes, and severe mitochondrial damage. The first two alterations are a general response to toxicity; the third is Cd specific. Although some chloroplasts were affected by Cd, they were not very sensitive to its action. The nuclear apparatus was not morphologically affec

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02856.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe structure of micronemata arising from the surface of the bloodstream form ofTrypanosoma gambiensewas studied by electron microscopy. In order to produce micronemata, trypanosomes were incubated in either 1) phosphate buffered saline supplemented with glucose (PBSG), 2) immune mouse serum or 3) PBSG after passage through a DEAE‐cellulose column. Electron microscopic examination of the parasite revealed the presence of thread‐like micronemata arising from the anterior end and from the flagellar pocket regardless of the incubation conditions. Negative staining revealed a distinct peripheral fringe layer with nodular protrusions covering the entire surface of the micronema. The distribution and number of intramembrane particles (IMP) on the P and E faces of the micronema were similar to those of the flagellum of T.gambiense, indicating a close relationship between the membrane structure of the micronema and the flagellum. Micronemata became fragmented and adhered to each other after incubation of the parasite in the media for 12 h. Since micronemata tend to have the characteristics of adhesiveness and fragmentation, fragments of these structures might adhere to various host organs. Dispersal of potential antigenic material might be responsible, in part, for the induction of the host immune respo

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02857.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTMouse omentum was studied after intraperitoneal challenge with tachyzoites ofToxoplasma gondii. Parasites inhabit omental histiocytes, fibroblasts, mesothelial cells, and free peritoneal macrophages. Recently infected cells showed enhanced metabolic and functional activity. Villous projections of the parasitophorous vacuole wall appeared, usually opposite the anterior pole of the parasite. In mesothelial cells, projections formed terminal swellings not observed in other infected cells. Activation of host cells was followed by reduction of the density of the cytoplasmic matrix, autophagosome formation, and intracellular edema, indicating the damage. The wall of the parasitophorous vacuole loses the supporting host cell endoplasmic reticulum that was attached to the vacuole just after entrance of the parasite into the cell. Then lysis of the parasitophorous vacuole and complete cell destruction occurs. The growth of parasites in undamaged cells does not coincide with the inflammatory response. Inflammation of the peritoneum develops only after the start of mass destruction of infected cells. Thus tachyzoites ofToxoplasmaexert significant pathogenic effects by their ability to activate the host cell, causing lysis of the parasitophorous vacuole and subsequent destruction of the entire cell.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02858.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe glycerophospholipids of the protozoonTetrahymena pyriformisW are unique in that the polyunsaturated fatty acid γ‐linolenate (18:3Δ6,9,12) is a major component of both thesn‐C‐1 andsn‐C‐2 positions.Tetrahymenawere incubated with [1‐14C]γ‐linolenate. The positional distribution of the radiolabeled fatty acid in the three major glycerophospholipids was determined. [1‐14C]γ‐linolenate was found at both carbons of the three lipids, in general agreement with the mass distribution of γ‐linolenate, except for markedly greater labeling at thesn‐C‐2 position of phosphatidylcholine. We hypothesize that an acyltransferase exists inTetrahymenathat can esterify γ‐linolenate at both carbons during g

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02859.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe longitudinal flagellum ofCeratium triposmoves in two dissimilar ways: undulation and retraction. The undulatory wave is planar and has a wavelength of 74.3 ± 9.6 μm and an amplitude of 14.2 ± 2.3 μm in sea water. The beat frequency is 30 Hz at 20°C, pH 8.0. The retractile motion is unique toCeratiumand is triggered by mechanical stimulation on the cell body, especially at the tip of the apical horn. When it retracts, the longitudinal flagellum folds every 4–5 μm along the flagellum. Cinematographic study showed that the flagellum folded from tip to base and was finally installed into the sulcus, a groove on the ventral side of the cell. This motion is completed in sea water within 28 msec. The retracted flagellum then re‐extends and restores the undulation within a few seconds. The flagellum unfolds in the proximal portion first, then the distal, and finally the middle portion. Fixation always triggers the retraction. Scanning electron microscopy showed that the flagellum is folded and secondarily twisted in a helix. A new fiber in addition to the flagellar axoneme was found in the retracted flagellum by phase microscopy. This fiber (R‐fiber) seems to contract during the retraction to fold th

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02860.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe cell surface ofTritrichomonas foetuswas characterized by using 18 highly purified lectins with specificities for N‐acetyl glucosamine, N‐acetyl galactosamine, galactose, mannose, and sialic acid. The specificity of the lectin‐induced cell agglutination was verified by inhibition of the agglutination with the specific sugars. By using cytochemical techniques associated with electron microscopy, carbohydrates were detected on the cell surface ofT. foetus.The following techniques were used: periodic acid‐thiosemicarbazide‐silver proteinate, concanavalin A‐horseradish peroxidase, and ruthenium red. Anionic sites were detected on the cell surface of the protozoan at pH's 1.8 and 7.2 with the use of colloidal iron hydroxide and cationized ferritin particles, respectively. The binding of colloidal iron particles, as well as the agglutination induced by the lectin fromLimulus polyphemus, indicated the presence of sialic acid on the cell surface

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1981.tb02861.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY