摘要:

SYNOPSIS.Protozoology, along with other cell sciences, has profited immeasurably during the last 25 years from the application of electron microscopy and other new technics to studies of cell structure and function. Protozoa were among the first objects examined with the electron microscope in the 1940's and an extensive literature in protozoan ultrastructure has accumulated since then. Some examples of recent investigations of ciliate cortical ultrastructure are selected to illustrate the importance of protozoan studies to the development of fundamental concepts of cell biology. Ciliates are choice subjects for analysis of ciliary structure and motility and of myoneme contractility. Membrane‐limited alveoli contribute to the structure of the characteristic ciliate pellicle and provide evidence of how multiple pellicular membranes may affect cell‐surface activities. The striated fibrils and microtubules associated with ciliate kinetosomes resemble those of other cell types but are more highly organized; wherever they occur, these structures appear to be related to the development and maintenance of polarity and asymmetry of cells and organelles. Their stability and the precision of their arrangement in ciliates make them peculiarly suitable for the study of the properties and behavior of such fibrous organelles and also for investigation of the morphogenetic role of the kinetos

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05151.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.Histomonas meleagridiswas isolated from eggs ofHeterakis gallinarumby culturing artificially hatched eggs in a modified DeVolt's alkaline serum medium. The presence of the protozoon in the cultures was established by microscopic examination and confirmed by producing histomonosis in turkeys by intracecal inoculation with quantities of the cultures.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05152.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.Cultures ofTelotrochidium henneguyi, begun with logarithmic phase cells, were employed in an effort to produce synchronized fission by heat treatment. The cells tolerated a temperature range of 20–50 C; temperatures above 50 were lethal. When cells were exposed to a single shock for 30 min, 30–40 produced 0–50% encystment with total excystment after 10 min exposure to room temperature (heat shock range). No encystment occurred between 20–30 (intershock range). Encystment and excystment time varied directly with temperature between 40–50.The most effective procedure for inducing synchronized fission consisted of 6 cycle program of 38/28 C (shock temperature/intershock temperature) administered for 15/15 (shock/intershock duration in min). Division indices (DI = cells dividing/total population X 100 =%) ranged from 12–66% with a mean of 37.25%. In control cells, division indices ranged from 2–20% with an average of 12%. Inferences from these independently derived findings

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05153.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.Phase and interference cinemicrographs of cilia ofParamecium multimicronucleatum, immersed 3–24 hours in 1.0% methyl cellulose, revealed that 1) inswimming Parameciumthe cilia beat with a traveling helical wave from base to tip rather than with the back and forth movement usually assumed, 2) during ciliary reversal the cilia merely change direction, but continue to beat with a traveling helical wave, and 3) instationary Parameciumthe beat is conicoidal. The traveling wave appears as an undulatory wave about 1 1/4 wave lengths long in both surface and profile views, and therefore must be helical. Envelope of the wave is cylindrical except near the base. Observations were confirmed in media without methyl cellulose by means of high speed cinemicrography, up to 4000 frames/sec.The back and forth movement, as described in all textbooks and monographs, is based mostly on 1) analogy to the abfrontal cilia (cirri) ofMytilus, which do beat with a back and forth movement, and 2) conclusions drawn from fixed preparations which do not represent what actually happens in a living animal.In a stationaryParameciumthe envelope of the beat is conicoidal as seen in profile, but probably is a spiral wave, i.e., similar to a helix but increasing in diameter from base to tip. This change in wave form could be caused by the increase in resistance of the water in a stationary organism over one that is moving.Cilia and flagella (also ciliates and flagellates) are usually distinguished on the basis of wave form, but the present observations, together with previous data on flagella, show that such distinctions are untenabl

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05154.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.The distribution of acid phosphatase was investigated at the ultrastructural level inParamecium caudatum.Acid phosphatase occurs in endoplasmic reticulum, Golgi apparatus, food vacuoles, autophagic vesicles, vacuolar and dense bodies. Some slight deposits are also seen in the mitochondria.These observations point out that this hydrolase activity is related to digestive processes. The enzyme, originating from the endoplasmic reticulum and Golgi apparatus reaches the food vacuole or autophagic vesicle likely via the reticulum. The digestion of the bacteria or of the enclosed organelle gives rise to electronopaque material which is later found in dense bodies. These dense bodies are likely secondary lysosomes and it is possible that they may fuse with the young food vacuole or with autophagic vesicles.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05155.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS. Sporozoites ofEimeria tenellawere injected into the peritoneal cavity of normal chickens and chickens immunized againstE. tenella.In some experiments normal scrum and serum from resistant chickens were injected prior to the injection of sporozoites. After 15 or 30 minute periods of intraperitoneal incubation, exudates were harvested and the occurrence of intracellular sporozoites was determined.Only macrophages and degranulated granulocytes were observed to contain sporozoites. There was no significant difference between the number of macrophages obtained from normal chickens (normal macrophages) which contained sporozoites and the number of macrophages obtained from immune chickens (immune macrophages) which contained sporozoites. Significantly fewer immune macrophages treated with immune serum contained sporozoites than untreated normal or immune cells, normal macrophages treated with either serum, or immune macrophages treated with normal scrum.Sporozoites in untreated normal macrophages did not appear to be harmed by the intracellular environment, based on structural observations. The majority of sporozoites in macrophages from all other groups were difficult to distinguish within the cytoplasm and were visibly distorted.It is hypothesized that the presence of fewer infected macrophages in exudates of immune chickens and serum‐treated normal chickens was caused by an enhanced ability of these cells to destroy the parasite.Similar observations were noted in the case of sporozoites within degranulated granulocytes of experimental groups. The lack of understanding of the degranulation phenomenon makes it difficult to interpret these finding

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05156.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.Flagellates of 7 species from 5 genera of the family Trypanosomatidae were prepared for electron microscopy using a combination of surface tension spreading on a simplified Langmuir trough followed by critical point drying. These technics opened the cells and showed the microtubular complex in its 3‐dimensional configuration or in a flat sheet with the inside surface facing‐up.Tears originated near the flagellar end and proceeded in a posterior direction usually paralleling the tubules. Major differences in the spreading pattern were species‐specific. A connection between the flagellum and microtubules was not shown but strongly indicated by their constant association in all degrees of spreading. Most microtubules follow a spiral course from the flagellar end toward the posterior apical area and terminate short of the apex. It is suggested that the concept of antero‐posterior orientation in the genusTrypanosomabe reconsidered.Cells ofLeptomonas collosomashowed, without exception, a clockwise spiral as the tubules approached the posterior apex. Therefore, both the direction of spiraling and the manner of spreading were consistent.The number of microtubules varied among cells of the same species as well as on different levels of the same cell. Highest counts coincided with the level of greatest circumference. No connections or anastomoses between tubules were found. The microtubules are believed to have limited flexibility. Changes in diameter were interpreted to mean flattening had occurred. An intertubular substance, believed to surround the microtubules in the living cell, was present in all

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05157.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.All stages (except conjugation) of the life cycle inAcineta tuberosa(Suctoria) were studied in the electron microscope. Budding starts with the invagination of a small pellicular area near the opening of the vacuole and bearing rows of barren basal bodies. Some of these basal bodies are incorporated into the swarmer‐anlage and give rise to 8 rows of cilia, while the other basal bodies remain barren on the mother cell's side of the brood pouch. They will provide their own genetic continuity and later give rise to the swarmer of the next generation. Kineties are not spaced on the growing swarmer‐anlage until their cilia are fully grown. Further details on the stalk‐forming crganelle and general features of the development of the larvae are given.Metamorphosis starts with the formation of basal disc and stalk. The stalk‐forming material is released thru scopular pores into a tube‐like mold formed by the scopula after having been pulled inward. Later, scopula pores spread from the scopular area proper and move upward. On their way to the apical part of the animal the cuticle is secreted. The differentiation of tentacles is described and new observations regarding a possible mode of haptocyst formation are given.The results are discussed with respect to the morphogenetic potentialities of cortical structures i

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05158.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Book reviewed in this article:Strelkov, A. A., K. M. Sukhanova and I. B. Raikov, eds. 1969.Progress in Protozoology. Abstracts of Papers Read at the IIIrd International Congress on Protozoology, Leningrad, 2–10 July, 1969.Curds, C. R. 1969.An illustrated key to the British fresh water ciliated protozoa commonly found in activated sludg

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05159.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.Trophozoites and what appear to be early spore forms of a parasitic protozoan present in the spinal cord of the lungfishPolypterus enlicheriare described. They are probably intra‐ and extracellular invaders into the anterior horn and are frequently located near capillaries. They provoke a glial response.The organisms have some myxosporidan features (7) and are tentatively classified as cnidosporidan

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb05160.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY