bluuebunny/crossref_metadata_2025 huggingface dataset:
Storage Polysaccharide in Coccidial Sporozites after Excystation and Penetration of Cells
Authors: VETTERLING JOHN M. , DORAN DAVID J.
Published: May 2007

SYNOPSIS. Eimeria acervulina, E. necatrix, and E. meleagrimitis sporozoites were examined for carbohydrates by cytochemical methods during dormancy, after excystation, and after penetration of cells. The only carbohydrate found was amylopectin, a homogeneous polymer of glucose. It was distributed in 3 regions: (a) in front of the anterior refractile globule, (b) around the nucleus, and (c) behind the posterior refractile globule. The relative amounts decreased after excystation and penetration of cells until only small amounts remained around the nucleus. The quantity of amylopectin decreased following excystation from 30.0‐36.7 to 9.4‐13.3 μg glucose/106 oocysts. Over a 6 yr period of storage at 4 C, there was a decrease in the quantity of amylopectin in dormant sporozoites of E. acervulina from 33.3 μg glucose/106 oocysts at 3 mos to 1.5 μg at 6 years. Coincidentally, 3 month‐ and 1 year‐old oocysts of E. acervulina produced patent infections in chicks with a dosage of 5 × 104 oocysts, but only a few of the oocysts that had been stored for 2 years were infective; a dosage of 2 × 106 oocysts was necessary to produce a patent infection. Oocysts which had been stored 6 years did not produce a patent infection.

It was concluded that amylopectin is the energy source for excystation and subsequent penetration of cells. Small amounts of amylopectin are used during dormancy and, when the content in the sporozoite falls below a certain level, the sporozoites lack sufficient energy to infect cells.
Effect of Holothurin on Trypanosoma lewisi Infections in Rats
Authors: STYLES TWITTY J.
Published: May 2007

SYNOPSIS. Crude holothurin from the Bahamian sea cucumber Actinopyga agassiz, inoculated intraperitoneally into rats with Trypanosoma lewisi infection, altered the host‐parasite relationship. The effect was measured by a study of parasite population during infections. Rats treated with holothurin prior to and simultaneously with an infection of trypanosomes had lower parasitemias than controls. A higher level of parasitemia was observed in treated after infection with trypanosomes. Both dosage and timing appeared to have been important parameters of the observed effect. The reticuloendothelial system is suspected to play a role in these findings.
Axenic Cultivation and Electron Microscopy of Two Species of Choanoflagellida1
Authors: GOLD KENNETH , PFISTER ROBERT M. , LIGUORI VINCENT R.
Published: May 2007

SYNOPSIS. Semi‐defined basal media have been formulated for 2 species of axenically reared choanoflagellates. High cell yield of Acanthoecopsis sp. is routinely obtained. Diaphanoeca grandis grows less well, but continuous serial transfers assure cells in good phyiologic condition. Loricas of both species have been examined by electron microscopy for gross structural details.
Fission in Heteropolar Tandem Grafts of the Ciliate Stentor coeruleus*
Authors: TARTAR VANCE
Published: May 2007

SYNOPSIS Stentor pairs fused by their posterior ends show persisting mutual adhesion, tho they eventually pull apart. When immobilized in methyl cellulose these grafts constricted in 2 in the line of heal. In no other type of stentor graft has such deliberate separation been observed.
Action of Nitrofuran Derivatives on the Chloroplast System of Euglena gracilis: Effect of Light
Authors: McCALLA D. R. , REUVERS ANTOON
Published: May 2007

SYNOPSIS. When cultures of Euglena are exposed to nitro‐furantoin in the light, there is extensive bleaching and, at higher concentrations, killing. In the dark the same concentrations have essentially no effect. The enhanced activity in light is a consequence of the rapid photolysis of nitrofurantoin to yield 5‐nitro‐2‐furaldehyde which is, in turn, destroyed by light. Nitrofuraldehyde and several other nitrofuran derivatives bleach at low concentrations in the dark.

Of 14 nitrofuran derivatives tested, only 4 Schiff's bases which were readily decomposed to nitrofuraldehyde in light were more active in the light than in the dark.
The Fine Structure of the Sporozoite of Lankesteria culicis
Authors: SHEFFIELD HARLEY G. , GARNHAM P. C. C. , SHIROISHI TSUGIYE
Published: May 2007

SYNOPSIS. The sporozoite of Lankesteria culicis was studied by light and electron microscopy, after excystation in the intestine of Aedes aegypti 1st stage larvae. The sporozoite was 9.5–10.0 μ long with a blunt anterior end and a tapered posterior region. The organism was enclosed by a typical pellicle consisting of an outer and an inner membrane with underlying subpellicular microtubules. The anterior end had a conoid with 2 associated rings, a polar ring which served as a termination of the subpellicular microtubules and a flask‐shaped structure situated internal and posterior to the conoid. A micropyle consisting of a collar formed from the inner membrane and lacking an invagination of the outer membrane was present near the anterior end of the parasite. The nucleus was centrally located and had a peripheral concentration of chromatin and a central nucleolus. One or more mitochondria were observed in the vicinity of the nucleus.
The Preparation of Congenic Strains of Tetrahymena1
Authors: ALLEN SALLY LYMAN , LEE PATRICIA H. T.
Published: May 2007

SYNOPSIS. Congenic strains of syngen 1, Tetrahymena pyriformis, were produced by backcrossing the F1 hybrid between inbred strains C2 and D to strain D in 12 consecutive backcrosses, with selection for certain C2 genes, and then using genomic exclusion to induce homozygosity. Six congenic strains of high breeding performance are available. Five differ from strain D in single genes at 5 different loci. The 6th strain differs at all 5 loci. Assuming the size of the Drosophila gene (4 × 104 nucleotide pairs), we can calculate that strains differing from D by single genes have a heterozygous segment 3 genes long while The strain which differs from D by 5 genes has 5 heterozygous segments and 15 genes contributed from strain C2. A 40‐fold increase in heterozygosity would be found with a gene size of 103 nucleotide pairs. This means that in using these strains for biochemical work we must be aware that some genetic noise still remains.
Scanning Electron Microscope Observations on Some Life History Stages of Carchesium polypinum (Ciliata, Peritrichia)1
Authors: ZAGON IAN S.
Published: May 2007

SYNOPSIS. Sessile zooids, and mobile telotrochs and microgamonts of Carchesium polypinum (Protozoa, Ciliata, Peritrichia), were examined by scanning electron microscopy. The results were compared to earlier light and electron microscope studies in order to investigate structural changes concerned with adaptation and differentiation. Telotrochs and microgamonts always had a contracted peristome and usually had a long phalange of cilia. Striae around the contracted buccal apparatus in all 3 stages were convoluted and often had thickened margins; those in telotrochs and microgamonts had oral‐aboral ectoplasmic cross‐connections. Nonbuccal striae of telotrochs and microgamonts varied in structure and height differences between epiplasmic peaks and alveoli surface membranes. The number of striae were constant in all 3 stages. Pellicular pore structure did not vary in any of the stages examined and resembled parasomal sacs located near buccal structures. Fully relaxed sessile zooids had ectoplasmic ridges coursing from polykinety kinetosomes and cilia to an area in front of the ciliated portion of the haplokinety; these ridges were interpreted to be the interkinetal fibers. Telotroch bands of sessile zooids consisted of 2 or 3 parallel ectoplasmic ridges which circled the aboral region and contained structures resembling pores. Telotroch bands in telotrochs and microgamonts had 2 enlarged, parallel ectoplasmic ridges circling the aboral region; telotroch band cilia were found between these ridges. In addition, a fold‐like, ectoplasmic structure extended beyond the 2 ridges and was located between the telotroch band cilia and the aboral ridge. The epiplasmic shelf surrounding the stalk in sessile zooids was enlarged in telotrochs, and cilia were seen in the scopula depression. No scopula organelle was seen in any microgamont.
The Purification of DNA from the Genomes of Paramecium aurelia and Tetrahymena pyriformis1
Authors: ALLEN SALLY LYMAN , GIBSON IAN
Published: May 2007

SYNOPSIS. Methods are described for the recovery of highly purified DNA from Paramecium aurelia and Tetrahymena pyriformis in high yields. Our DNA is only slightly contaminated with RNA and carbohydrate, and little or no protein can be detected. We could not reduce the RNA (orcinol‐positive material) by further treatment (sephadex or hydroxyapatite chromatography and preparative CsCl gradients). At the extreme our DNA is contaminated with 15–20% RNA but the real value is most likely considerably lower than this. The DNA we have prepared from Paramecium and Tetrahymena shows all the properties of double‐stranded, high molecular weight DNA when characterized by temperature melting, CsCl density gradient centrifugation and hydroxyapatite and sephadex chromatography. When denatured, it absorbs to nitrocellulose filters. The 2 major results of importance from our work reported here are: (1) There is similarity in base composition of DNA from different syngens of Paramecium (28% G+C for syngens 1, 2, 4, 5, and 9 and 29–30% G+C for syngen 8) while there is variation between the syngens of Tetrahymena (24–31% G+C for syngens 1, 4, 7, 10, 11, and 12); (2) the density of any Paramecium DNA varies depending upon whether the cells are grown in the presence of bacteria or in axenic medium. Our results are compatible with observations previously reported for Tetrahymena but contradict those made for Paramecium. The earlier reports of differences in base composition between syngens of Paramecium are probably due in large part to the use of stocks grown on bacteria.
An Explanation for the Limited Contractility of Stentor amethystinus Leidy, 1880
Authors: CRAGG PAUL R.
Published: May 2007

SYNOPSIS. The contractile ability of Stentor amethystinus was compared to that of other highly contractile stentors. S. amethystinus contracted very little. A structural examination was made in an attempt to explain this difference in behavior. The results suggested that the endoplasm might act in this species as a hydrostatic skeleton contained within a continuous sheath of contractile material. It is also suggested that S. amethystinus might in fact be only slightly extensible as opposed to showing limited contraction.
Isospora petrochelidon sp. n. (Protozoa: Eimeriidae) from the Cliff Swallow, Petrochelidon pyrrhonota
Authors: STABLER ROBERT M. , KITZMILLER NANCY J.
Published: May 2007

SYNOPSIS.
Isospora petrochelidon
sp. n. (Protozoa: Eimeriidae) is described from the cliff swallow, Petrochelidon pyrrhonota, from Douglas County, Colorado. Oocysts were passed primarily between 4 and 9 p.m. Sporogony was completed by 24 hr in 3% aqueous potassium dichromate at 21–28 C. The ellipsoid to ovoid oocysts averaged 25.2 × 22.2 μm. The oocyst wall was smooth, colorless, and single‐layered. The 2 polar granules were disc‐shaped, each adjoining a sporocyst. The lemon‐shaped sporocysts averaged 18.4 × 10.8 μm. There was no membrane enclosing the sporocyst residuum and sporozoites. Two fledgling Isospora‐free swallows fed sporulated oocysts began passing them on day 4 and died with massive infections on day 5. Data from these birds indicate that schizogony occurred during nighttime hours, gametogony during the day. Endogeny was found throughout the intestine distal to the gizzard, with schizogony confined to the convoluted glands of the subvillar mucosa and gametogony to the villar epithelium. Sporocysts released from mechanically ruptured oocysts excysted in 2% pancreatin within 5 min. Sporulated oocysts fed to a pigeon squab, duckling and cockerel produced no infections.
An Electron Microscope Study of Autoinfection in Neogregarines (Sporozoa, Neogregarinida)
Authors: ŽIŽKA ZDENEK
Published: May 2007

SYNOPSIS. In an electron microscope study of the neogregarine Farinocystis tribolii Weiser 1953 in the fat body of the larvae of the flour beetle Tribolium castaneum, empty oocysts and adjacent sporozoites of the gregarine were found. The empty oocysts contained host cell cytoplasm, a residuum only slightly larger than that in mature oocysts, and some remnants of the oocyst membrane pressed tightly against the inner surface of the wall. Apparently normal sporozoites were found near the empty oocysts and no damaged ones were seen. It is assumed that the sporozoites go on developing in the host, i.e., that autoinfection takes place.
Fine Structure of the Contractile Vacuole Pore in Paramecium*
Authors: McKAN JAMES A.
Published: May 2007

SYNOPSIS

The pore through which a Paramecium contractile vacuole communicates with the external environment is a 1.2 μm long and 1 μm diameter cylindrical orifice in the pellicle. During diastole, the vacuole:pore junction is closed by a substantial diaphragm which parts to the side at systole. The diaphragm is composed of inner and outer membranes continuous with the vacuole and pore membranes, respectively, and an intervening cytoplasmic layer containing filaments and irregular membranous tubules and vesicles. Microtubules, organized into 2 sets, are an important component of the pore apparatus. One set of ∼ 16 microtubules forms an annulus around the pore. These microtubules are organized into a right‐handed helix with a pitch of 0.5‐0.6 μm, and thus complete slightly more than 2 turns in their course from the level of the diaphragm to the pore outer lip. They appear to be embedded in a layer of dense material immediately adjacent to the pore membrane. The other set consists of 5 or more bands of 10–20 microtubules which radiate in a slight left‐handed helix from an insertion at the pore out over the vacuole surface to the ampullae.
Electrophoretic Characterization of Classical Tetrahymena pyriformis Strains*
Authors: BORDEN D. , WHITT G. S. , NANNEY D. L.
Published: May 2007

SYNOPSIS

The electrophoretic mobility patterns of 8 enzymes have been examined in 43 classical strains of Tetrahymena pyriformis. The strains may be assorted into sets on the basis of a high degree of similarity of their mobility patterns. Strains of similar designation are frequently in different sets, whereas differently labeled strains may be in the same set. It is proposed that new strain designations be made on the basis of phenotypic similarity.
Contractility and its Control in Peritrich Ciliates*†
Authors: ALLEN RICHARD D.
Published: May 2007

SYNOPSIS

A review of the recent literature on the structure and physico‐chemical properties of the myoneme and its specialization, the spasmoneme, of peritrich ciliates was made. Myonemes are composed of tightly packed bundles of 3–5 nm microfibrils which parallel, more or less, the long axis of the bundle and are of indefinite length. The presence of contractility in these ciliates is correlated with the presence of myonemes. Associated with the microfibrils is a system of membrane‐bound tubules and saccules continuous with the endoplasmic reticulum (ER). This system is known to accumulate calcium. Myonemes differ from muscles in their structure, solubility properties, birefringence pattern, and in the time during the contraction‐relaxation cycle at which they require energy. They may be related more closely to the cytochalasin B‐sensitive microfibrils of higher organisms than to muscles. Contraction of extracted stalks can be induced solely by raising the calcium ion concentration above a certain threshold. Thus the calcium‐accumulating myoneme‐associated ER would appear to play an important role in the control of myoneme contractility. A specialization at the interface between the myoneme and the ER membranes is described as it appears in Vorticella and Opercularia. This structure, called a linkage complex, is found both in the body myonemes and the spasmoneme and links the membranes of the ER to the microfibrils. It also has microfilaments that pass from the ER‐myoneme interface to the surface membranes. The uniqueness of this structure and its location suggests that it may play a role in controlling the movements of calcium between the ER and myoneme and also in transmission of messages from the pellicular membranes, possibly the alveolar sacs, to the ER.
Studies of Blastocystis hominis
Authors: ZIERDT CHARLES H.
Published: May 2007

SYNOPSIS

Blastocystis hominis, grown in Boeck‐Drbohlav culture medium, modified by the omission of rice starch and the addition of 20% human serum and mineral oil cover to the Locke's solution overlay, can assume 3 morphologic forms. In the absence of human serum the vacuolated form, which divides by binary fission predominates. In medium with high serum content the granular form appears, with 3 types of granules. Spheroid or more elongate cytoplasmic granules predominate. In older organisms, lipid granules are found either in the peripheral cytoplasm or in the central vacuolar space. In occasional cells, variable numbers of reproductive granules develop in the central vacuolar space. These latter granules are released from the organism and give rise to typical B. hominis cells. The 3rd form, the ameba form, appears in small numbers in older cultures and in those treated with antibiotics. Ameba forms feed on bacteria and have slow pseudopodial activity. Exposure to oxygen causes rapid damage to cell membrane, with resulting leakage and collapse.
Inhibition of Protein Synthesis: A Mechanism of Amebicide Action of Emetine and Other Structurally Related Compounds*
Authors: ENTNER NATHAN , GROLLMAN ARTHUR P.
Published: May 2007

SYNOPSIS

New amebicides usually have been discovered by empirical screening procedures while other drugs, such as emetine, were adopted after their clinical efficacy was demonstrated. Emetine, puromycin, and cycloheximide are amebicides recently shown to act as inhibitors of protein synthesis in animal cells; the present study was designed to determine the general relationship of this mode of action to amebicidal activity. Our results indicate that amebicides structurally related to emetine inhibit protein synthesis in Entamoeba histolytica. It seems likely that the lethality of many amebicides may be attributed to specific effects on macromolecular synthesis in E. histolytica.
The Fine Structure of Four “Species” of Amoeba*
Authors: FLICKINGER CHARLES J.
Published: May 2007

SYNOPSIS

The fine structure of Amoeba discoides, Amoeba dubia, and Amoeba amazonas was studied and compared with that of Amoeba proteus. The different kinds of amebas showed general similarities but differed in the ultrastructural details of their organelles. With respect to fine structure, A. discoides was indistinguishable from A. proteus, while both A. dubia and A. amazonas had distinctive features. The nuclei of all had a prominent honeycomb‐like fibrous lamina, but A. dubia differed from the others in the distribution of nucleoli within the nucleus. The mitochondria of A. amazonas were unusual in having a variable pattern of cristae, some being plate‐like and others tubular. Golgi bodies in A. amazonas had a greater proportion of vesicles and a smaller number of cisternae than those of the others, while Golgi bodies in A. dubia had highly flattened cisternae without a lining of filamentous material such as is found in the other types. The plasma membrane of A. dubia also lacked the prominent filamentous cell coat common to A. proteus and other amebas. The relation between the Golgi apparatus and the cell coat and the significance of the degree of development of the cell coat for pinocytosis and other phenomena is considered. The experimental use of these cells, including the formation of hybrids by nuclear transplantation is discussed.
Mechanism of Photoaccumulation in Paramecium bursaria
Authors: SAJI M. , OOSAWA F.
Published: May 2007

SYNOPSIS

Responses of Paramecium bursaria to light intensity changes were investigated. The resting paramecia show a direction changing response (photophobic response) to a sudden decrease of light intensity, whereas no response was shown to an increase in intensity. The critical intensity decrease dIc necessary to show the response was measured at various values of initial light intensity, and the ratio dIc/I was found to be equal to ∼0.15. The swimming paramecia show different behavior depending on their swimming direction in the spatial gradient of light intensity. Paramecia show direction change more frequently when they are swimming down the gradient than in the opposite direction. This difference in the rate of direction changing is 13–17%. These results may offer an explanation for the mechanism of photoaccumulation.
Life Cycle of Polytomella caeca (Phytomonadida, Polyblepharidae)
Authors: LEWIS ELIZABETH , MUNGER CARET , WATSON RUTH , WISE DONALD
Published: May 2007

SYNOPSIS. Polytomella caeca (Phytomonadida, Polyblepharidae) reproduce by binary fission and sexual reproduction. The sexual process increases in frequency as the population becomes denser. Normally 2 monoecious isogametes engage their anterior flagella prior to fusion, which occurs by merging of the cells from their anterior to their posterior ends. This is followed by a period of zygotic enlargement before cleavage of the zygote into 4 daughter cells. Encystment occurs throughout the flagellates' bloom until they represent 80% of the individuals at the end of the bloom. Cysts are a resistant, not reproductive stage. The observations were made over long periods of time by following individual flagellates in microcultures and by viewing living cells taken at various stages from larger cultures.
Ultrastructure of Symbiotic Bacteria in Normal and Antibiotic‐Treated Blastocrithidia culicis and Crithidia oncopelti*
Authors: CHANG K.‐P.
Published: May 2007

SYNOPSIS. An electron microscope study of diplosomes in Blastocrithidia culicis and bipolar bodies in Crithidia oncopelti has shown that both entities appear to be intracellular symbiotes and have a similar fine structure. They are enclosed by 2 unit membranes which are separated by a large space of very low density. The outer membrane is derived probably from the host cell. The matrix of the symbiotes is composed of dense ribosome‐like particles and of areas of low density containing fine fibrillae. The particles are of the same size as ribosomes in bacteria and the fibrils have the characteristics of bacterial DNA. Thus, the lucid areas with fibrillae correspond to the nucleoids in bacteria. These observations suggest that the symbiotes are bacteria.

The effect of chloramphenicol (CAP) and penicillin G (PCL) on these symbiotic bacteria was studied by culturing the host flagellates in media containing the antibiotics. The effect was analyzed at different intervals after the treatment by electron microscopy. After single treatment in the blood broth containing 0.08% (w/v) CAP, symbiotes appeared to have enlarged nucleoids, became deformed and eventually degenerated. In Grace's medium (supplemented with 10% fetal bovine serum) containing 0.6 or 2.4% (w/v) PCL, symbiotes of C. oncopelti remained unaltered, whereas some symbiotes of B. culicis became pleomorphic. Symbiotes of both species persisted after repeated transfers in PCL media and reverted to normal forms when transferred to PCL‐free media. Sensitivity of symbiotes to CAP provides further evidence of their bacterial nature. The effect of PCL on the symbiotes of B. culicis suggests the presence in their cell envelopes of mucopeptide, which probably provides rigidity for maintaining the bacterial shape of the symbiotes.
La Genèse des Mérozoïtes chez la Coccidie Eimeria necatrix. Etude Ultrastructurale*
Authors: DUBREMETZ JEAN FRANCOIS
Published: May 2007

RESUME. Les schizontes de 2 ème génération d'Eimeria necatrix ont étéétudiés au microscope électronique. La différenciation des mérozoïtes est associée à la dernière mitose, qui ne semble pas différer essentiellement des précédentes. Les mérozoïtes se développent à la périphérie du schizonte. Le conoide et 22 microtubules sous pelliculaires, probablement induits par les centrioles, et le complexe membranaire interne ainsi que les précurseurs des rhoptries, qui semblent issus de l'appareil de Golgi, apparaissent auprès de chaque pôle nucléaire, sous la membrane du schizonte. Ces organites sont les premiers inclus dans les ébauches de mérozoïtes. Puis, le noyau, le dictyosome et les vésicules multimembranaires pénètrent dans les futurs mérozoïtes. Les micronèmes, probablement formés par l'appareil de Golgi, et les grains d'amylopectine sont produits plus tard, quand les mérozoïtes se séparent du reliquat cytoplasmique. Le mode de genèse de ces divers organites et les relations entre le dernière mitose et la différenciation sont discutés.

SYNOPSIS. Second generation schizonts of Eimeria necatrix were studied with the aid of the electron microscope. Differentiation of daughter merozoites is associated with the last mitosis, which is not significantly different from the earlier ones. The merozoites develop at the periphery of the schizont. The conoid and 22 subpellicular microtubules, probably induced by centrioles, and the inner membranes complex and the rhoptry anlagen which seem to be produced by the Golgi apparatus, appear close to each nuclear pole, just near the schizont membrane. These organelles are the first to appear in the merozoite anlagen. Then, nucleus, dictyosome and multimembranous vesicles enter the budding merozoites. Micronemes, probably originating from Golgi apparatus, and amylopectin granules are produced later, when daughter merozoites separate from the residuum. The genesis of these various organelles and the relation between the last mitosis and differentiation are discussed.
Omikron, ein essentieller Endosymbiont von Euplotes aediculatus*†
Authors: HECKMANN KLAUS
Published: May 2007

ZUSAMMENFASSUNG. Der Süßwasserciliat Euplotes aediculatus beherbergt in seinem Cytoplasma 900–1000 stäbchenförmige Symbionten, die für seine Vermehrung essentiell zu sein scheinen. Durch Wachstum in Gegenwart von Penicillin kann Euplotes von seinen Symbionten befreit werden, es führt dies jedoch stets auch zu einem Verlust der Teilungsfähigkeit. Eine Reinfektion ist bei etwa 4% der Zellen möglich, die dann nach 4–5 Tagen sich wieder zu vermehren beginnen.

Die Endosymbionten wurden sowohl lichtmikroskopisch als auch elektronenmikroskopisch untersucht. In ihrer Feinstruktur und Färbbarkeit gleichen sie, wie kappa und andere von Paramecium her bekannte “killer”‐Partikel, gramnegativen Bakterien. Sie unterscheiden sich von diesen Symbionten jedoch dadurch, daß ihre DNA im Cytoplasma nicht homogen verteilt ist, sondern sich in 3–9 schon lichtmikroskopisch erkennbaren Zentren konzentriert. Die in Euplotes vorkommenden Symbionten lassen keine “killer”‐Aktivität erkennen. Sie werden omikron‐Partikel genannt.

SYNOPSIS. The fresh water ciliate Euplotes aediculatus contains in its cytoplasm 900–1000 rod‐shaped symbiotes which appear to be essential for division. Growth of Euplotes in the presence of penicillin results in loss of these symbiotes and simultaneously in a loss of the ciliate's ability to divide. Reinfection with the symbiotes can be achieved in 4% of the cells which then resume growth after a lag period of 4–5 days.

The endosymbiotes have been studied by light and electron microscopy. In their fine structure and staining reaction they resemble gram‐negative bacteria as do kappa and other killer particles of Paramecium. The symbiotes of Euplotes, however, are unusual in that their DNA is not distributed throughout the cytoplasm but is localized in 3–9 areas (nucleoids), which are visible even in the light microscope. No killing activity seems to be associated with the symbiotes. Following the practice of referring to those endosymbiotes by Greek letters they are here designated omikron particles.
Cryopreservation of Trypanosoma cruzi Bloodstream Forms*
Authors: FILARDI LENY S. , BRENER Z.
Published: May 2007

SYNOPSIS. Recovery rates of T. cruzi bloodstream forms subjected to several methods of cryopreservation in liquid nitrogen and at ‐73 C are reported. Inoculations of animals with cryopreserved and nonpreserved trypomastigotes revealed that prolonged storage at ‐196 C apparently did not change the biologic characteristics of different T. cruzi strains. The reproducibility and consistency of results suggest that “cryobanks'’or “reference centers'’may be established.
High Speed Cinemicrography of the Direct Photophobic Response of Euglena and the Mechanism of Negative Phototaxis*
Authors: DIEHN BODO , FONSECA JAMES R. , JAHN THEODORE L.
Published: May 2007

SYNOPSIS. The shock reaction of Euglena gracilis strain Z to a sudden increase in light intensity (the “direct photophobic response”) was examined by high speed cinemicrography. The response is expressed as a turning reaction toward the dorsal side of the cell, after a transduction time of 0.1–0.5 sec after the onset of stimulation. Transduction times, turning rates, and flagellar beat frequencies were measured by analyzing the filmed sequences. The experimental data are consistent with a mechanism of directional homeostasis in negative phototaxis that is based upon shading of the photoreceptor by the cell's posterior end.
Fusion of Host Cell Secondary Lysosomes with the Parasitophorous Vacuoles of Leishmania mexicana‐inlected Macrophages
Authors: ALEXANDER JAMES , VICKERMAN KEITH
Published: May 2007

SYNOPSIS. Secondary lysosomes of cultured mouse peritoneal macrophages were labeled with the electron‐dense colloid saccharated iron oxide; the identity of the labeled structures was checked by the Gomori reaction for acid phosphatase. Amastigotes of Leishmania mexicana mexicana derived from mouse lesions were used to infect these macrophages in vitro. In electron micrographs of thin sections of infected macrophages the labeled secondary lysosomes were seen fused with the parasitophorous vacuoles without preventing subsequent multiplication of the parasites. A similar fusion probably occurs in vivo, and may provide a pathway through which not only nutrients but also drugs and host antibodies could reach the intracellular parasite.
Isolation of Amylopectin Granules and Identification of Amylopectin Phosphorylase in the Oocysts of Eimeria tenella
Authors: WANG C. C. , WEPPELMAN R. M. , LOPEZ‐RAMOS B.
Published: May 2007

SYNOPSIS. Amylopectin granules were purified from Eimeria tenella oocysts following digestion with sodium dodecyl sulfate and pronase. The oval granules had a uniform size of 0.5 × 0.7 μm, and consisted of only glucose polymers. α‐Amylase treatment yielded 235 nmoles of maltose from the granules from 106 unsporulated oocysts and 93 nmoles maltose from those from 106 sporulated oocysts.

Amylopectin phosphorylase activity was detected in the cytoplasm of unsporulated oocysts of E. tenella. It had a specific activity of 13 U/mg protein in crude extracts, and a pH optimum of 6.0. The Km values determined were 9.1 mM for glucose‐1‐phosphate and 5.6 mM for glucose end groups in potato amylopectin. Enzyme activity declined at a linear rate during sporulation, sporulated oocysts containing less than 8% of the activity of unsporulated oocysts. No amylase‐type activity was found in the parasite.
Fine Structure of an Unidentified Protozoon in the Epithelium of Rainbow Trout Exposed to Water with Myxosoma cerebralis*
Authors: DANIELS STEPHEN B. , HERMAN ROGER L. , BURKE C. N.
Published: May 2007

SYNOPSIS. An intracellular protozoon was discovered in the epithelium of young rainbow trout (Salmo gairdneri) exposed for as short a time as 1 hr to water known to contain infective stages of Myxosoma cerebralis. Light‐ and electron‐microscopic examination of this tissue revealed what appeared to be a proliferative stage (presumptive schizont) of a sporozoon; other possible stages in the life cycle were also observed. The relationship of this unidentified protozoon to M. cerebralis remains unresolved.
Particle Ejection from the Cytoproct of Tetrahymena
Authors: BLUM J. J. , GREENSIDE HENRY
Published: May 2007

SYNOPSIS. Egestion of carmine particle‐containing food vacuoles from the cytoproct of Tetrahymena pyriformis has been analyzed by high‐speed cinemicrography. The vacuole may enter into position in the cytoproct ∼ 7 sec before ejection, and forms a distinct bulge beyond the outline of the cell surface for over 2 sec prior to ejection. The ejection process itself requires 20–80 msec.
Light‐Induced Body Movement of Euglena gracilis Coupled to Flagellar Photophobic Responses by Mechanical Stimulation*†
Authors: MIKOLAJCZYK EWA , DIEHN BODO
Published: May 2007

SYNOPSIS. In low viscosity media, Euglena gracilis strain Z responds to a sudden change in light intensity by a cessation of forward movement, followed by a reorientation of the locomotor flagellum which results in turning of the cell around the lateral axis (photophobic response). At a viscosity interface between low [∼ 1 cP (centipoise)] and high (4000 cP) media, the cells exhibit avoidance responses or become immobilized in the higher viscosity medium. Upon changing the light intensity, free swimming cells have photophobic responses, while immobilized ones undergo body contractions. For cells immersed in media of varying viscosity, the delay between light stimulation and body contraction (transduction time) is shortest at high viscosities. From 500 to 2000 cP, where the cells are capable of both movement and light‐induced body contractions, there is a logarithmic dependence of the transduction time on the viscosity. The transduction time does not vary appreciably with the intensity of the primary light stimulus within a range of 0.14‐1.13 kW/m2.
Life Cycles of Two Isospora Species in the Canary, Serinus canarius Linnaeus*
Authors: BOX EDITH D.
Published: May 2007

SYNOPSIS. The endogenous stages of Isospora serini Aragão and Isospora canaria Box are described from experimentally infected canaries, Serinus canarius Linnaeus. Unlike other Coccidia, the first part of the I. serini life cycle takes place in mono‐nuclear phagocytes. Five asexual generations are described from this cell type; 2 additional asexual generations and the sexual stages take place in the intestinal epithelium. Isospora canaria, on the other hand, has a conventional coccidian life cycle in that all of the endogenous stages are in the epithelium of the small intestine, with 3 asexual generations and the sexual generation described in the duodenal epithelium. The 2 species differ in their position relative to the nucleus of the intestinal epithelial cell. Isospora serini is usually on the lumenal side of the nucleus while I. canaria is below the nucleus, toward the basement membrane. The prepatent period is 4–5 days for I. canaria and 9–10 days for I. serini. Patency lasts for 11–13 days in I. canaria infections, but duration of oocyst output is more chronic in I. serini infections, persisting for as long as 231 days. Both species have a diurnal periodicity of oocyst discharge which occurs in late afternoon and evening.
Scanning Electron Microscopy of Schizogony in Eimeria tenella
Authors: MADDEN P. A. , VETTERLING J. M.
Published: May 2007

SYNOPSIS. Developing 2nd‐ and 3rd‐generation schizonts of Eimeria tenella were found in the ceca of chicks infected orally with sporulated oocysts. Several free 2nd‐generation schizonts, which varied in diameter from 11 to 21.6 μm, were found on the epithelial surface of the cecum. Some schizonts appeared to have lost merozoites. Other schizonts were intact, one of which was surrounded by an unbroken membrane that followed the contours of the merozoites. Third‐generation schizonts, much smaller than 2nd‐generation schizonts and with fewer merozoites, were found only on cut or fractured surfaces of the cecal tissue. Third‐generation merozoites appeared shorter and thicker than those of the 2nd‐generation and were attached to the schizont residuum. A form with conical protuberances and another with 4 triangular segments were found; they were believed to be developing stages 3rd‐generation schizonts.
Further Studies of Breeding Restrictions among Crypthecodinium cohnii‐like Dinoflagellates. Evidence of a New Interbreeding Group
Authors: HIMES MARION , BEAM CARL A.
Published: May 2007

SYNOPSIS. Studies on sexual compatibility among populations of different origins of axenically cultivated, heterotrophic, homothallic dinoflagellates resembling Crypthecodinium cohnii have been undertaken using motility mutants and complementation testing. We showed previously that one interbreeding group or biologic species can be found on the East and West coasts of the United States, thus far associated only with Fucus. In addition, we found several strains of these organisms each of which, though fertile in intrastrain crosses, appeared infertile with all other isolates. A continuation of these studies has revealed another biologic species of wide geographic distribution (Taiwan, California, Florida, New York) and apparently associated with sea weeds other than Fucus.
The Effect of Glucose on the Biochemical and Ultrastructural Characteristics of Developing Euglena Chloroplasts*
Authors: SCHWELITZ FAYE D. , CISNEROS PAULINE L. , JAGIELO JULIA A.
Published: May 2007

SYNOPSIS. Chloroplast development is inhibited in Euglena gracilis strain Z, when greened in a medium containing glucose. This inhibition is reflected not only in the pattern of chlorophyll accumulation but also in the chloroplast ultrastructure and activities of the 2 light reactions of photosynthesis. Chloroplasts of cells greening in the presence of glucose are delayed in déveloping certain structures. Photosystem I activity develops at about the same rate as that of the controls during the first 48 h of greening, after which it develops at a slower rate. The rate of development of photosystem II activity in cells greening in a glucose medium lags considerably behind that of the controls until the later hours of greening. There are similarities between glucose inhibition and chloramphenicol inhibition of chloroplast development. Glucose may inhibit a step in chloroplast development ultimately controlled by the chloroplast genome.
Précisions Temporelles sur les Processus de la Stomatogenèse de Tetrahymena paravorax analysés en Microscopie Photonique
Authors: METENIER GUY , GROLIERE CLAUDE‐ALAIN
Published: May 2007

Resume.

Une analyse des séquences morphogénétiques du CiliéTetrahymena paravorax montre que: (A) La durée de la stomatogenèse de bipartition des formes microstomes en croissance exponentielle représente 45% du temps de génération (stade 1—20%; stade 2—3%; stade 3—3%; stade 4—5%; stade 5—5%; stade 6—9%). (B) La division cytoplasmique est inégale (les proters sont plus petits que les opisthes); la différence de taille initiale entre les 2 produits de fission est probablement compensée par une prolongation de la période de croissance chez le proter. (C) Le pourcentage maximum de réorganisation buccale microstome → macrostome pour les populations asynchrones atteint –˜ 70% au bout de 210 mn d'incubation dans la stomatine. (D) L'initiation de la stomatogenèse de remplacement oral est connectée avec la fin d'une période dont la durée minimale est approximativement celle du stade 0 du cycle normal d'interdivision des microstomes; cette initiation est retardée chez les microstomes exposés à la stomatine dès le début du cycle cellulaire. (E) Le primordium buccal de division peut se résorber en présence de stomatine et la stomatogenèse antérieure peut commencer avant que ne soit terminée cette résorption; la résorption n'est plus induite au‐delà d'un point du stade 5 qui précède le début de la constriction du corps cellulaire.

SYNOPSIS.

An analysis of the morphogenetic sequences in the ciliate Tetrahymena paravorax has shown that: (A) The duration of predivision stomatogenesis in exponentially growing microstomes occupies 45% of the generation time (stage 1—20%; stage 2—3%; stage 3—3%; stage 4—5%; stage 5—5%; stage 6—9%). (B) Cytoplasmic division is unequal (the proters are smaller than opisthes); the initial size difference between the 2 fission products is presumably compensated by an increased growth period in the proter. (C) The maximum percentage of microstome‐to‐macrostome oral reorganization is –˜ 70% in asynchronous populations, 210 min after suspension in stomatin. (D) Initiation of oral replacement stomatogenesis is associated with the end of a period which has a minimum duration nearly equal to that of stage 0 characteristic of the normal inter‐division cycle of the microstomes; this initiation is delayed if exposure of microstomes to stomatin is begun at the onset of the cell cycle. (E) The buccal primordium formed in division can be resorbed in presence of stomatin and anterior stomatogenesis can start before the resorption is completed: this resorption is not induced if the cells have progressed beyond a point which precedes the beginning of the cell furrowing (stage 5).
Tip Transformation in Tetrahymena: A Morphogenetic Response to Interactions Between Mating Types*
Authors: WOLFE JASON , GRIMES GARY W.
Published: May 2007

SYNOPSIS.

In Tetrahymena thermophila subline B, a morphogenic alteration of the anterior end of cells of mating types III and VII results from a cellular interaction which precedes and is a prerequisite for pairing. Cell pairing begins 1 h after starved cells of complementary mating type are mixed. The 1 h‐long lag period is characterized by an actinomycin D‐sensitive inductive interaction in the first 30 min, followed by a maturation period. Tip transformation begins during the maturation period and continues after pairing. Scanning electron microscopy of deciliated cells reveals ridges which form a chevron meeting in a midline seam between the oral apparatus and the anterior tip. During transformation, the seam broadens until the ridged surface is completely smooth. Melding of the ridges also occurs at the tip of the cell resulting in its blunted appearance. Cells of complementary mating types join in the region of this modified surface, which eventually becomes a specialized cell junction perforated by cytoplasmic bridges. Thus, pursuant to an inductive interaction the structure of the tip of cells is modified in anticipation of the pairing event. Rate of cell pairing might be limited by rate of tip transformation.
Attempted Cross‐Transmission of Coccidia Between Sheep and Goats and Description of Eimeria ovinoidalis sp. n.
Authors: McDOUGALD L. R.
Published: May 2007

SYNOPSIS.

Attempted infection of 2 young lambs with oocysts of Eimeria christenseni from a goat was unsuccessful. Negative results were obtained also when young kids were fed oocysts of Eimeria ninakohlyakimovae from sheep. There was no difficulty in infecting lambs with the sheep coccidium resembling E. ninakohlyakimovae nor goats with the goat coccidium E. christenseni. Oocysts from the goat measured 38.4 × 26.7 m̈m, but were easily distinguished from Eimeria ahsata from the sheep by sporocyst size and shape, and from Eimeria ovina by oocyst size. Eimeria ninakohlyakimovae‐like oocysts from sheep averaged 23.0 ×18.2 m̈m and were morphologically indistinguishable from previously reported goat coccidia.

Since no cross infections of sheep and goats could be accomplished with oocysts of Eimeria sp. characteristic of one or the other host, I concluded that sheep coccidia previously known as E. ninakohlyakimovae are distinct from morphologically similar goat coccidia and therefore constitute a separate species. Since the name E. ninakohlyakimovae was first used for coccidia from the goat, the sheep coccidium is renamed Eimeria ovinoidalis with oocyst structure and endogenous stages similar to those previously described from the sheep.
The Fatty Acid Composition of Paramecium aurelia Cells and Cilia: Changes with Culture Age
Authors: KANESHIRO EDNA S. , BEISCHEL LINDA S. , MERKEL STEVEN J. , RHOADS DENNIS E.
Published: May 2007

SYNOPSIS.

The fatty acids of whole cells and cilia from Paramecium tetraurelia strains 51s and d,95 and from Paramecium octaurelia strain 299s were identified. Ciliates were grown axenically in 3 types of culture media. More than 30 fatty acid species were identified and their structures determined by gas chromatography, mass spectrometry, argentation chromatography, hydro‐genation, and fragmentation technics. The major fatty acids were hexadecanoic, octadecanoic, 9‐octadecenoic, 9,12‐octadecadi‐enoic, 6,9,12‐octadecatrienoic, and 5,8,11,14‐eicosatetraenoic acids. Minor variations in fatty acid compositions were observed in cells grown in the different culture media as well as among the 3 strains. Major changes in fatty acid compositions occurred with culture age and cell density. The cells accumulated exogenous lipids in cytoplasmic vesicles. These lipids were utilized as culture age progressed. Both cellular volume and lipid content were greater in young than in older cultures. Fatty acid compositions of both whole cells and cilia changed with age and had a relative decrease in saturated, short‐chained and odd‐numbered carbon acids. Cilia lipids were enriched in long‐chained, polyunsaturated acids as compared to lipids in whole cell extracts. Eicosatetra‐enoic acid (arachidonic acid) increased to the greatest extent with age in both cellular and ciliary lipids, accounting for 20–60% of the total fatty acids in cilia. The age‐related change in fatty acid composition in Paramecium is among the largest observed in eukaryotic organisms. It was concluded that some minor fatty acids found in Paramecium lipids were incorporated directly from certain culture media and that Paramecium had w3, 6, and 9 pathways for polyunsaturated fatty acid biosynthesis.
Emetine Binding to Ribosomes of Entamoeba histolytica—Inhibition of Protein Synthesis and Amebicidal Action*
Authors: ENTNER NATHAN
Published: May 2007

SYNOPSIS

After demonstration that emetine is amebicidal by inhibiting protein synthesis, the question arose whether active protein synthesis is required for emetine's amebicidal effect. The answer appears to be “no,” as derived from experiments on intact amebae. Responses were compared for log‐ and stationary‐growth phase amebae. In the latter, protein synthesis is significantly slower, and sensitivity to emetine, i.e. degree of inhibition of protein synthesis, was maintained independently of rate of protein synthesis. Both stages equally bound tritiated emetine to their ribcsomes. Binding of [3H]emetine was not affected by certain drugs that interfere with energy metabolism, protein synthesis, and/or ribosomal function, e.g. dinitrophenol, puromycin, chloroquine, and acriflavin. High concentrations of EDTA combined with puromycin (which disaggregates ribosomes into their subunits) lowered binding by 50%.

In chase experiments the ribosomes of intact amebae were prelabeled with [3H]emetine or [3H]isoemetine, then exposed to relatively high concentrations of unlabeled emetine. Labeled isoemetine was displaced almost completely, whereas no displacement of [3H]emetine occurred; evidently, the high stability of the emetine‐ribosome binding is due in part to a hydrogen‐bonding reaction of the C‐1' atom of the emetine molecule with the chain‐elongation site. Finally, evidence was obtained that capacity to bind emetine is an index of drug resistance.