bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of P‐Enolpyruvate Carboxykinase and of Glyconeogenesis in Tetrahymena by 3‐Mercaptopicolinic Acid*
Authors: LIANG TONY , RAUGI GREGORY J. , BLUM J. J.
Published: May 2007

SYNOPSIS. Tetrahymena grown overnight in deep cultures were incubated for 1 hr with [1‐14C]labeled substrates in the presence or absence of 3‐mercaptopicolinic acid (3‐MPA). 3‐MPA inhibited appearance of label in glycogen from bicarbonate, acetate, pentanoate, octanoate, and succinate, but not from glycerol or glucose. In vitro assays of phosphoenolpyruvate carboxylase and phosphoenolpyruvate carboxykinase activity showed that both enzymes were about equally distributed between the particulate and cytosol fractions. 3‐MPA inhibited phosphoenolpyruvate carboxykinase from both the cytoplasmic and particulate fractions, but had no effect on phosphoenolpyruvate carboxylase from either location. These results suggest that the in vivo effects of this drug are due to inhibition of glyconeogenesis at this site.
Nebela tuberculata comb. nov. (Arcellinida), its History and Ultrastructure
Authors: OWEN GORONWY , JONES E. E.
Published: May 2007

SYNOPSIS. The name Nebela tuberculata comb. nov. is proposed for the testate ameba formerly known as Difflugia tuberculata (Wallich, 1864) Archer, 1867. The generic reassignment is based upon the test construction material which is shown, by electronmicrographs and X‐ray diffraction, to be autogenous regular and irregular silicious rods. A brief history of the animal is recounted utilizing works of several authors who have encountered the ameba over the last century.
The Genus Leptotheca (Protozoa: Myxosporida) in Macrourid fishes and Sablefish, Anoplopoma fimbria*
Authors: MOSER MIKE , NOBLE ELMER R.
Published: May 2007

SYNOPSIS. Five species of Leptotheca, one new, were found in the macrourid fishes and the sablefish, Anoplopoma fimbria. Those species which were geographically widespread in numerous host species showed little variation. Two Leptotheca species were found both in the gall bladder and urinary bladder/kidney.
Quantitative Ultrastructural Investigations of Mitochondrial Development in Leishmania donovani During Transformation*
Authors: BRUN RETO , KRASSNER STUART M.
Published: May 2007

SYNOPSIS. The ultrastructure of the mitochondrion during transformation of Leishmania donovani from amastigote to promastigote stages was studied by morphometric analysis. There was a slight but significant decrease in relative mitochondrial volume (Vvli) during transformation. This decrease was linear with time for at least 27 hr. No change in relative lipid inclusion volume (Vvli) was observed during transformation. The ratio of inner to outer mitochondrial surface membrane densities (Svmii:Svmio) also remained unchanged. Although the relative number of cristae remains unchanged after transformation, there is an increase in cristae number in the portion of the kinetoplast opposite the flagellum.
Observations on the Ultrastructure of Uronema spp., Marine Scuticociliates*
Authors: KANESHIRO EDNA S. , HOLZ GEORGE G.
Published: May 2007

SYNOPSIS. Observations of the ultrastructure of marine scuticociliatids, tentatively assigned to the genus Uronema, were made by light, transmission electron, and scanning electron microscopy. Giant, cortically oriented mitochondria filled the subpellicular, intermeridional areas, and were in close association with the epiplasm immediately under the inner alveolar sac membranes. Reconstructions of serial sections of the posterior poles of ciliates indicated that the intermeridional mitochondria could fuse at that point and the entire chondriome might at times be a single organelle. A system of tubules was observed to be intimately associated with the mitochondria in the posterior region. The tubules anastomosed and were directed posteriorly into the region of the nephridial‐contractile vacuole system. The outer surfaces were coated with projections arranged in helical patterns. The system may be regarded as a fluid segregation organelle. The tripartite nature of the polar basal body complex observed by silver impregnation was confirmed by transmission electron microscopy. The 3 structures were the basal body of the caudal cilium and 2 parasomal sacs. A prominent ring around the caudal cilium was observed by scanning electron micrcscopy; it is probably responsible for the silver deposition surrounding the polar basal body complex that can be seen by light microscopy of silver‐impregnated specimens. The ultrastructure of the nonmotile caudal cilium and its kinetosome was unremarkable, being like that of the motile, somatic cilia. The micronuclear and macronuclear outer membranes were continuous at several sites. Such interconnections explain the intimate physical relationship between the nuclei during interphase in many ciliates, and could be a structural basis for chemical communication between the 2 nuclear types. Within the cytoplasm surrounding the opening of the cytoproct, numerous clear vesicles were observed. Their position and appearance suggested that the cytoproct may be involved in the elimination of solutions as well as solids. Food vacuoles, cortical microtubules, lamellar vesicles, disc‐shaped vesicles, mucocysts, and a contractile vacuole and its pore were also observed.
Digestion of Added Homologous Algae by Chlorella‐Bearing Paramecium bursaria
Authors: WEIS DALE S.
Published: May 2007

SYNOPSIS. Endosymbiotic algae from Paramecium bursaria when added to the culture medium are ingested by Chlorella‐bearing P. bursaria at a rate of 2,000 algae/organism/day. That the ingested algae are digested and assimilated by the ciliates is suggested by the more rapid growth of Paramecium when algae are added to the medium (G= 40 hr with algae compared to 190 hr without). The digestion by the ciliates of exogenous algae contrasts with the survival of these algae under normal growth conditions. It is suggested that the protection of the endogenous algae is related to their location in peripheral perialgal vacuoles.
Studies on Plasmodium Ookinetes. 1. Isolation and Concentration from Mosquito Midguts*
Authors: WEISS MARTIN M. , VANDERBERG JEROME P.
Published: May 2007

SYNOPSIS. In a method for isolating a relatively clean suspension of concentrated Plasmodium berghei ookinetes from infected midguts of Anopheles stephensi at appropriate times after the infective blood meal, the ookinetes are freed from the midguts by enzymatic digestion, and then concentrated by means of a BSA/renografin gradient. The mean number of ookinetes recovered/midgut was 152. More than 95% of the recovered ookinetes were viable by the criteria of motility, incorporation of adenosine and leucine, and appearance on light and electron microscopic examination. Trypan blue exclusion was not a valid criterion for viability. These ookinetes were not useful for in vitro studies of further development due to the presence of contaminating microorganisms. Our attempts to determine their potential for further development in vivo have similarly not been successful. Nevertheless, our ability to obtain large numbers of ookinetes at defined times during development now permits further studies on their structure, biochemistry, and physiology, as well as comparison with ookinetes formed in vitro.
Blood Parasites of Taiwan Birds*
Authors: MANWELL REGINALD D. , ALLEN CONSTANCE S. , KUNTZ ROBERT E.
Published: May 2007

SYNOPSIS. Blood films were examined from 1477 birds of Taiwan (193 species, 49 families). Haemoproteus Kruse was by far the commonest parasite, with Leucocytozoon Danilewski a not very close second. It is probable that some of the Haemoproteus infections represented new species, and 1 occurring in the Bamboo Partridge (Bambusicola thoracica sonorivox Gould) seemed characteristic enough to justify recognition as such; the name Haemoproteus bambusicolae sp. n. is proposed for this organism. Malaria was found in 77 birds, the greatest number of infections occurring in the Bamboo Partridge. Most of them were caused by Plasmodium juxtanucleare Versiani & Gomes, a pathogen of chickens, but a number were due to an undetermined species of Plasmodium. The Bamboo Partridge may be a reservoir host of the former. A few other identified species (P. rouxi Sergent & Sergent, P. hexamerium Huff, P. tenue Laveran & Mesnil) were seen, as well as some unidentified ones. Plasmodium tenue was seen in Garrulax canorus taewanus Swinhoe, a babbler: until now it was known only from the Pekin Robin (Leiothrix luteus Scopoli), also a babbler, in which we have found it extremely common. Sixty‐four microfilarial infections were identified; they were especially frequent in the Button Quail (Turnix suscitator rostrata Swinhoe).
Effect of Fetal Calf Serum Fractions and Proteins on Division and Transformation of Trypanosoma (Schizotrypanum) cruzi in Vitro*
Authors: O'DALY JOSE A.
Published: May 2007

SYNOPSIS. Division and epimastigote‐to‐trypomastigote transformation of Trypanosoma cruzi were observed in O'Daly's SM medium supplemented, in place of whole fetal calf serum, with fractions of this serum, its partially purified proteins, or with mixtures of these fractions and proteins. In addition to their division‐promoting effects, most but not all serum fractions stimulated [3H]thymidine uptake by the flagellates. As revealed by TEAE‐cellulose column chromatography and immunoelectrophoresis, the serum fractions were altered during the logarithmic growth phase of the trypanosomes.
Ultrastructure of Sporulation in the European Flat Oyster Pathogen, Marteilia refringens—Taxonomic Implications*
Authors: PERKINS FRANK O.
Published: May 2007

SYNOPSIS. By fine‐structural studies of speculation stages in the European flat oyster pathogen Marteilia refringens this organism is shown to be a member of the protozoan class Haplosporea. This conclusion is based on observations that haplosporosomes are found in plasmodia and spores and that sporoplasm delimitation occurs by internal cleavage within plasmodia. During sporulation plasmodia become sporangiosori by enlarging, cleaving internally into ∼ 8 sporangia, each of which then cleaves internally into 3 or 4 spore primordia. The primordia divide into 3 uninucleate sporoplasms of graded sizes, the smallest lying in an eccentrically located vacuole of the medium‐sized one, and the latter situated within an eccentric vacuole of the largest. Haplosporosomes are found only in the cytoplasm of the largest sporoplasm. Mature, living spores measure 3.9(3.5–4.5)μm diameter and are enclosed in a continuous wall without a mantle of epispore cytoplasm as in other Haplosporea.

An amended genus and species description of Marteilia refringens is presented, based on light and electron microscope observations.
The Cell Surface of Trypanosoma musculi Bloodstream Forms. I. Fine Structure and Cytochemistry*†
Authors: DWYER DENNIS M. , D'ALESANDRO PHILIP A.
Published: May 2007

SYNOPSIS. An extracellular surface coat was observed at the fine‐structural level on the outer lamina of the pellicular and flagellar membranes of intact Trypanosoma musculi bloodstream forms. The surface coat had a mean width of 9.2 nm, and was composed of a somewhat electron dense, uneven, fibrillar‐like matrix. Brief trypsin treatment of living blood forms completely removed the cell surface coat.

Several cytochemical methods applicable to electron microscopy were used to detect the presence and distribution of carbohydrates in the trypanosome's surface coat and pellicular membrane. The polycationic dye compounds employed were: ruthenium red, ruthenium violet, Alcian blue chloride, and lanthanum nitrate. Electron‐dense stain reaction products, indicative of polysaccharides, were evident in the surface coat of cells treated with these dyes, which also agglutinated both living and glutaraldehyde fixed cells. Like the surface coat, the pellicular membrane of trypsinized cells gave strong positive staining reactions with the several dyes, indicating the presence of membrane bounded carbohydrates, and living and glutaraldehyde‐fixed trypsinized cells were agglutinated with the polycationic stains. Bloodstream forms were treated with the enzymes, α‐amylase, dextranase, and neuraminidase. No obvious morphologic difference, however, was apparent between the surface coat of untreated cells and those subjected to treatment with any of the various glycoside hydrolase enzymes. Further, these enzymes had no apparent gross effect on the staining affinity of the surface coat for the several polycationic dyes. Cationized ferritin was used to visualize the negative cell surface charge of T. musculi bloodstream forms. Large quantities of cationized ferritin were bound in the surface coat matrix. Glycoside hydrolase enzyme treatments had no apparent effect on the amount of ferritin bound in the surface coat. Cationized ferritin was bound also to the outer lamina of the pellicular membrane in trypsinized cells, which had quantitatively less ferritin bound per surface unit area than bloodstream forms untreated by the enzyme. Living and glutaraldehyde‐fixed cells were agglutinated with cationized ferritin. The results obtained in the various experiments indicated that polyanionic polysaccharides were constituent terminal ligands of the surface coat matrix and pellicular membrane in T. musculi bloodstream forms.
Allogromia laticollaris: A Foraminiferan with an Unusual Apogamic Metagenic Life Cycle*
Authors: Mc ENERY MARIE E. , LEE JOHN J.
Published: May 2007

SYNOPSIS. The life cycles of 3 strains of Allogromia laticollaris, a monothalamous foraminiferan, have been studied. Each of the strains had a different, nonclassical, and basically apogamic, life cycle. The Cold Spring Harbor (CSH) strain regularly alternated between 2 agamontic forms: agamont I (uninucleate and diploid) and agamont II (multinucleate and diploid). The complete life cycle took 26 days. Sexual reproduction was rare (0.01%) and autogamous. Small numbers of organisms also underwent budding, binary fission, and cytotomy. The life cycles of the Towd Point (TPA) and Sippewissett (SIP) strains were comparatively abbreviated. Agamont II dominated their typical life cycles, which were completed in 16‐18 days. The life cycle of SIP was basically a continuous cycling of the agamont II phase. Approximately 75% of the schizozoites of the TPA strain developed into agamont II. The other 25% alternated between agamont II and agamont I phase.

In the CSH strain schizozoites with ∼ 8 (range 5‐15) nuclei characterized newly formed agamonts II. More nuclei (∼ 25) were found in the other 2 strains. The nuclei in young agamonts II underwent rapid morphologic changes leading to a “mushroom‐like” chromosome appearance and extensive RNA synthesis. Nucleolar material accumulated at the nuclear periphery and eventually was discharged to the cytoplasm. Karyokinesis took place without the breakdown of the nuclear membrane.

The single nucleus of young agamont I forms was proportionally quite large. The S1 phase occurred quite early (2‐5 days) in this part of the life cycle. RNA in the CSH strain formed a compact, subcortical, coarsely granular ring, while in the TPA it was cortical and differentiated into finely granular matrix with randomly distributed coarse granules. During the G2 phase the nucleus became further enlarged and eventually amoeba‐form. Intermediate stages in nuclear breakdown were not found.
Fine‐Structural Aspects of Microgametogenesis of Eimeria magna in Rabbits and in Kidney Cell Cultures*
Authors: SPEER CLARENCE A. , DANFORTH HARRY D.
Published: May 2007

SYNOPSIS. The fine‐structural aspects of development of microgamonts of Eimeria magna were studied in kidney cell cultures and in experimentally infected rabbits. Spheroidal masses of gamont‐like cytoplasm containing ribosomes, polyribosomes, and amylopectin granules were found within the parasitophorous vacuole; these bodies were apparently pinched off the surface of the gamont. Nucleoli were present in the early stages of nuclear division but disappeared as development proceeded. Spindles were eccentric and the nuclear membrane always remained intact in dividing nuclei. Nuclei eventually became elongate in shape, compact, and electron dense at the end oriented toward the periphery and lucent centrally. Usually, only the dense portion was incorporated into the gamete as the gamete developed by protruding from the gamont surface. Fullyformed microgametes were biflagellate and contained a nucleus, a mitochondrion, and 8‐10 microtubules. Multiple‐membrane complexes, which apparently originated from the nuclear envelope or endoplasmic reticulum, were found within the gamont residual body. Occasionally, 2 or 3 micro‐ and/or macrogamonts were seen within the same cell. In some cells one or 2 micro‐ or macrogamonts as well as several merozoites were present in the same parasitophorous vacuole.
Fine Structure of Oocyst Transformation and the Sporozoites of Leucocytozoon dubreuili*
Authors: WONG TIN CHUI , DESSER SHERWIN S.
Published: May 2007

SYNOPSIS. The sporogonic stages of Leucocytozoon dubreuili in the midgut and salivary glands of the simuliid vectors was studied by electron microscopy. Young uninucleate oocysts have a pellicle that initially resembles that of the ookinetc. Numerous electron‐dense bodies and microtubules in the peripheral cytoplasm may be involved in the formation of the cyst wall. The dense bodies appear to give rise to the amorphous material of the wall. The tubules which run circumferentially beneath the oocyst's boundary probably serve as a skeletal support for the cell surface during deposition of the wall material. A subcapsular “space” which provides area for expansion of the developing sporozoites is formed in early multinucleate oocysts. The subcapsular “space” appears to be formed through a condensation of the peripheral cytoplasm, resulting in an osmotic gradient across the oocyst's limiting membrane. Consequently water diffuses out, creating a fluid‐filled space. Sporozoite formation begins with localized thickenings on the oocyst's limiting membrane. Subsequent extension of the thickened regions into the subcapsular “space” marks the onset of sporozoite budding. The process is highly synchronized, and culminates with the production of up to 150 sporozoites about the sporoblastoid body. The structure of sporozoites from mature oocysts and of the salivary glands of the vector is basically similar, although salivary gland sporozoites are more elongate and have numerous electron‐dense micronemes. The paired rhoptries in the latter sporozoites are more elongate and uniformly electron‐dense than in oocyst sporozoites.
Efficacy of Antibiotics A204 Sodium, A28695A, and A204np against Coccidia of Rabbits
Authors: FITZGERALD PAUL R.
Published: May 2007

SYNOPSIS. Three polycyclic, polyether, monocarboxylic acid antibiotics produced by and extracted from a strain of Streptomyces albus and designated A204 sodium, A28695A, or A204np, were specifically tested for activity against hepatic and incidentally against intestinal coccidia of rabbits. All were effective in preventing infections and acceptable to young rabbits when prepared in pelleted feed. Weight gain, however, was not as good in inoculated, medicated rabbits as in noninoculated, nonmedicated controls.

No gross pathologic changes were detected except in the livers of inoculated, nonmedicated controls which were severely infected and greatly enlarged. Livers of medicated rabbits were uninfected and normal in appearance and size.
Heterotrophic (Dark) CO2 Fixation by Euglena gracilis. Possible regulation by tricarboxylic acid cycle intermediates
Authors: PEAK J. G. , PEAK M. J.
Published: May 2007

SYNOPSIS. Heterotrophic (dark) CO2 fixation by Euglena gracilis strain Z varies with phase of batch culture and mode of nutrition. Dark CO2 fixation increased transiently during the growth of cells under photoautotrophic (CO2, light) and heterotrophic (glucose, dark) conditions. Cells grown heterotrophically with acetate or ethanol had no transient increase in fixation. The addition of acetate to a heterotrophically growing culture during the period of increasing dark CO2 fixation resulted in rapid elimination of this fixation. The results suggest that dark CO2 fixation in Euglena functions in anaplerotic feeding of the tricarboxylic acid cycle, drained by biosyntheses during growth. Induction of the glyoxylate cycle by acetate may provide an alternate source of tricarboxylic cycle intermediates, obviating the requirement for dark CO2 fixation as a source of the intermediates.
Aldolase Levels in Wild‐Type and Mutant Euglena gracilis
Authors: KARLAN ANDREW W. , RUSSELL GEORGE K.
Published: May 2007

SYNOPSIS. Wild‐type Euglena gracilis var. baciliaris, strains B and Z, synthesize 2 distinct fructose‐1,6‐diphosphate aldolases. Amounts of the 2 activities depend upon conditions of growth. The class I enzyme, with activity similar to that found in various photosynthetic tissues, is formed during regreening of dark‐grown cultures incubated in the light. Very low activity of the class I enzyme is also found in mutant strains W3BUL and W8BHL, both of which apparently lack plastid DNA. The significance of these findings is discussed.
Effect of 4‐Pentenoic Acid on Intermediate Metabolism of Tetrahymena*
Authors: LIANG TONY , RAUGI GREGORY J. , BLUM J. J.
Published: May 2007

SYNOPSIS. The growth of Tetrahymena pyriformis strain HSM was strongly inhibited by 4‐pentenoic acid. Supplementing the medium with acetate reversed the growth inhibition, but pyruvate was ineffective. Glycogen content was much lower in cells grown with 4‐pentenoic acid than in controls; this effect was not reversed by acetate or by pyruvate. There was little effect of 4‐pentenoic acid on the incorporation of label from [1‐14C]acetate, [2‐14C]glycerol, [1‐34]ribose, [U‐14C]fructose, or [1‐14C]glucose into CO2, but incorporation of label into glycogen was inhibited, the strongest inhibition being on acetate and the weakest (∼ 20%) on ribose, fructose, and glucose. A 3‐compartment model for quantitation of labeled acetyl CoA fluxes was shown to be applicable to Tetrahymena grown in the presence of 4‐pentenoic acid, and experiments were performed to establish the flux of [1‐14C]acetyl CoA into glycogen, lipids, CO2, glutamate, and alanine. It was evident from the results of these experiments that 4‐pentenoic acid did not appreciably inhibit β‐oxidation or lipogenesis, but markedly decreased the glyconeogenic flux of labeled acetyl‐CoA from the peroxismal and outer mitochondrial compartments.

At least 2 mechanisms have been proposed for the action of 4‐pentenoic acid: (a) reduction of the levels of acetyl CoA or free CoA and (b) direct inhibition of enzymes by 4‐pentenoyl CoA or its metabolites. Although 4‐pentenoic acid has little effect on acetyl‐CoA metabolism in the inner mitochondrial compartment, the present data suggest that the flux through the outer mitochondrial compartment of acetyl‐CoA derived from pyruvate is inhibited largely by the first, and that the glyconeogenic flux of acetyl‐CoA is inhibited largely by the 2nd mechanism.
Light and Electron Microscopic Observations on Encystment of Acanthamoeba palestinensis, Reich
Authors: LASMAN M.
Published: May 2007

SYNOPSIS. The ultrastructural changes occurring during encystment of Acanthamoeba palestinensis have been investigated. The cyst wall consists of endocyst and exocyst, both having the same fine structure. At irregular intervals in the cyst wall ostioles occupied by opercula are present. The nuclear membrane forms bulb‐shaped projections and releases vesicles bounded by double membranes into the cytoplasm. Dense nucleolus‐like bodies of different sizes and variable numbers are found in the nucleus of every cyst. The importance of the cyst structure as a taxonomic criterion is discussed.
Electron Microscopic Studies of the Development of Kinetes in Theileria annulata Dschunkowsky & Luhs, 1904 (Sporozoa, Piroplasmea)
Authors: MEHLHORN HEINZ , SCHEIN EBERHARD
Published: May 2007

SYNOPSIS. Gamogony of Theileria annulata Dschunkowsky & Luhs occurs within the intestine of nymphs of the tick Hyalomma anatolicum excavatum Koch. After the 5th day post repletionem (p.r.) of the ticks spherical and ovoid parasites were found within the intestinal cells. These stages were thought to represent fertilized macrogametes. These underwent a transformation process leading ultimately to the differentiation of a motile stage, the kinete, which leaves the intestinal cells on the 14th‐17th day p.r. and penetrates the alveoles of the salivary glands. The transformation of the stationary into a motile stage takes place by formation of a growing protrusion (= anlage) into an inner, enlarging vacuole. During this process the limiting membrane of the vacuole serves as the outer membrane of the developing motile stage, whereas the 2 inner membranes of its pellicle are newly formed. The steps of this differentiation in T. annulata are compared to the process of ookinete formation in haemosporina.
Effect of Chloramphenicol on Bacterial Endosymbiotes in a Strain of Amoeba proteus*
Authors: JEON K. W. , HAH J. C.
Published: May 2007

SYNOPSIS. The effect of chloramphenicol (CAP) on the bacterial endosymbiotes of a strain of Amoeba proteus was studied by growing the symbiotic amebae in media containing 0.5–1.6 mg/ml CAP for up to 4 weeks. Treatments with CAP caused such ultrastructural changes as expansion of the nuclear zone and deformation of symbiotes. The CAP treatment also damaged the mitochondria, e.g. disappearance of central and protrusion of peripheral cristae. Number of bacteria per ameba decreased to < 10% of control in CAP‐containing media, but no viable amebae became completely free of symbiotes. The resuts supported previous studies that amebae were dependent on endosymbiotes.
Correlation of Encystment and Division in Schizopyrenus russelli*
Authors: RASTOGI A. K. , SAGAR P. , AGARWALA S. C.
Published: May 2007

SYNOPSIS. Schizopyrenus russelli, a free‐living soil ameba, grows and encysts in the presence of bacteria. The encystment occurs with decline in the division rate. This is accompanied by incorporation of [U‐14C] glucose into cyst cellulose. The degree of multiplication (but not of encystment) is a function of bacterial concentration. Berenil, a trypanocidal drug, while allowing excystment, completely inhibited multiplication of emerged amebae and their encystment. Addition of this drug after 24 hr, when amebae had gone into a phase of active division failed to check encystment, although it still inhibited further multiplication of the amebae. The findings suggest that a phase of cell division may be a prerequisite for encystment.
An Examination of the Methods for Isolating Cellular Slime Molds (Dictyosteliida) from Soil Samples*
Authors: KUSERK FRANK T. , EISENBERG ROBERT M. , OLSEN AART M.
Published: May 2007

SYNOPSIS. Present methods for extracting cellular slime molds from soil samples are shown to be biased in favor of spores and microcysts. To alleviate this problem, a modified method is proposed together with a method for partitioning active (amebae) and inactive forms (spores and microcysts).
Timing and Regulation of Nuclear and Cortical Events in the Cell Cycle of Tetrahymena pyriformis*
Authors: SUHR‐JESSEN PETER B. , STEWART JOHN M. , RASMUSSEN LEIF
Published: May 2007

SYNOPSIS. Using continuous flow cultures based on the chemostat principle, we varied the cell generation times of the ciliate Tetrahymena pyriformis strain GL, from 4.9 to 22.2 hr and studied various parameters of the cell cycle at 28 C. These included: the duration of the periods required for oral morphogenesis, macronuclear division, cell division, G1 S, and G2. The size of individual cells was also measured.

Independent of the growth rate, the period of oral morphogenesis occurred during the last 90 min of the cell cycle. In all cases macronuclear and cell divisions took place during the last part of these 90 min, and the final macronuclear separation occurred just before final cell separation. The S‐period increased slightly, while the G1 and G2 both increased in roughly the same relative proportion to the increasing generation times. Slowly growing cells (generation time 20.5 hr) were shorter but broader and somewhat larger in volume than quickly growing cells (generation time 4.9 hr).
Serologic Analyses of Cell‐Surface Antigens of Acanthamoeba spp. with Plasma Membrane Antisera*†
Authors: STEVENS A. R. , KILPATRICK T. , WILLAERT E. , CAPRONI A.
Published: May 2007

SYNOPSIS. Antisera were raised against plasma membrane‐enriched fractions of the species Acanthamoeba castellanii and Acanthamoeba culbertsoni to determine whether cell‐surface antigens would facilitate species identification of Acanthamoeba isolated from the environment or in human infections. Acanthamoeba castellanii and A. culbertsoni plasma membranes were purified, after homogenization, by differential and isopycnic centrifugation. Electron microscopic examination of purified membrane samples showed an enrichment of membranes with a typical trilaminar structure. Occasionally, mitochondria were recognized in the electron microscope preparations. 5′‐Nucleotidase, Mg2+‐ATPase, and alkaline phosphatase were enriched 11‐fold, 2‐fold, and 7‐fold, respectively, in the A. castellanii membranes, as determined from analyses of the enzyme activities in whole cell homogenates and membrane preparations. 5′‐Nucleotidase was not detected in A. culbertsoni, but the activities of Mg2+‐ATPase and alkaline phosphatase were increased 2‐ to 3‐fold. Both membrane preparations showed no glucose‐6‐phosphatase activity and less than 5% contamination with succinic dehydrogenase. From assays of acid phosphatase activity, the most apparent contamination of the plasma membrane preparations was with membranes of phagocytic vacuoles. Acanthamoeba castellanii membrane antisera produced significant agglutination and fluorescence of homologous cells to titers of 1:8192 and 1:1024, respectively. Acanthamoeba polyphaga and Acanthamoeba rhysodes gave the most cross‐reactions in heterologous tests. They were agglutinated to a titer of 1:128 and positively fluoresced to titers of 1:32 and 1:64, respectively. Antisera of A. culbertsoni membrane agglutinated homologous cells at a dilution up to 1:4096 and produced homologous fluorescent titers up to 1:512. Other than agglutination of A. polyphaga to a titer of 1:128, these antisera did not cross‐react significantly with any remaining heterologous species. Three new isolates were identified with these plasma membrane antisera: 2 of them, contaminants from tumor tissue cultures, were identified as A. culbertsoni. Preliminary information is also given on the use of the membrane antisera for species identification of Acanthamoeba in several new cases of amebic encephalitis.
Reduced Pyridine Nucleotide Oxidases of Euglena gracilis var. bacillaris*
Authors: MOHANTY MAHENDRA K. , HUNTER FRISSELL R. , MYERS JOSEPH B.
Published: May 2007

SYNOPSIS. Cell‐free extracts of a streptomycin‐bleached strain of Euglena gracilis var. bacillaris have been examined for enzyme systems primarily responsible for the oxidation of reduced pyridine nucelotides. NADH lipoyl dehydrogenase, NADH and NADPH oxidase, NADH and NADPH diaphorase, and NADH and NADPH cytochrome c reductase have been demonstrated. The NADPH‐linked enzymes had lower activity rates and were less sensitive to N‐ethyl maleimide and p‐hydroxymercuribenzoate than their NADH‐linked counterparts. NADH cytochrome c reductase was the most sensitive to antimycin A. Michaelis‐Menten constants (Km) determined were as follows: NADH diaphorase, 350 μM; NADPH diaphorase, 200 μM; NADH cytochrome c reductase, 13 μM; NADPH cytochrome c reductase, 9 μM; NADH oxidase, 100 μM; NADPH oxidase 150 μM; NADH lipoyl dehydrogenase, 0.35 μM. Enzyme activities after storage at –5 C indicate that the diaphorases are less labile than the other tested enzymes, and the differential activities of the NADH and NADPH linked enzymes suggest that functionally they may have different roles.
Carbohydrate Effects on Amino Acid Transport by Trypanosoma equiperdum*
Authors: JACKSON† PETER R. , FISHER FRANK M.
Published: May 2007

SYNOPSIS. Uptake of 14C‐labeled alanine, glutamate, lysine, methionine, proline, and phenylalanine by Trypanosoma equiperdum during 2‐minute incubations occurred by diffusion and membrane‐mediated processes. Amino acid metabolism was not detected by paper chromatography of trypanosome extracts. Most of 18 carbohydrates tested for ability to alter amino acid transport neither changed nor significantly inhibited transport. Glucose, however, stimulated glutamate, lysine and proline transport; fructose stimulated lysine uptake and 2‐deoxy‐D‐glucose increased phenylalanine and methionine absorption. No evidence was found that the carbohydrates acted by binding to amino acid transport “sites.” Glucose inhibition of alanine, phenylalanine, and methionine uptake was linked to glycolysis. The rapid formation of alanine from glucose stimulated alanine release and, when glycolysis was blocked, glucose no longer inhibited alanine transport. Methionine and phenylalanine release was also stimulated by glucose. Glucose changed the ability of lysine, glutamate, and proline to inhibit each others’uptake, indicating that certain amino acids are preferentially absorbed by respiring cells. Analysis of free pool amino acid levels suggested that some amino acid transport systems in T. equiperdum are linked in such a way to glycolysis as to control the cell concentrations of these amino acids.
A New Microsporangial Protostelid, Microglomus paxillus gen. and sp. nov.*
Authors: OLIVE L. S. , STOIANOVITCH CARMEN
Published: May 2007

SYNOPSIS. Microglomus paxillus is described as a new genus and species of the subclass Protosteliida (Class Eumyceto‐zoa). It has been isolated only once from casuarina bark collected in Oahu, Hawaii. The new organism is characterized by a uninucleate ameboid trophic stage that feeds on bacteria and by sporocarps with spike‐like stalks terminated by microspo‐rangia containing tetrads of ameboid protoplasts or thin‐walled spores. No flagellate cells are produced. The tetrads are typically formed by successive bipartition following conjugate nuclear divisions in the sporogen. The cells of the tetrad are at first binucleate but soon become uninucleate as a result of nuclear degeneration. Variations in the process of sporogenesis are described.
Ultrastructural Observations of Experimental Naegleria Meningoencephalitis in Mice: Intranuclear Inclusions in Amebae and Host Cells*
Authors: SCHUSTER F. L. , DUNNEBACKE T. H.
Published: May 2007

SYNOPSIS. Primary amebic meningoencephalitis was experimentally produced in mice through intranasal instillation of pathogenic Naegleria fowleri. Experimental animals had a 64% mortality, with average time of onset of symptoms or death occurring on the 7–8th day following inoculation. Ultrastructural studies of the olfactory lobes from brains of dead (or sacrificed) animals revealed major concentrations of amebae in the perivascular regions; amebae were also seen to be under attack by host polymorphonuclear leukocytes, and in the lumina of blood vessels. Amebae in brain tissue contained 30 nm intranuclear particles arranged in clusters. In the brains of some mice, dead presumably as a result of amebic meningoencephalitis, particles and crystalloids were observed in the nuclei of degenerating cells of the central nervous system. Some alternatives are examined to explain a possible relationship between ameba intranuclear particles and mouse brain cell intranuclear inclusions.
Tails of Tetrahymena
Authors: SATIR PETER , SALE WINFIELD S.
Published: May 2007

SYNOPSIS. The source of force generation of beating cilia and flagella is an interaction between the doublet microtubules mediated by the dynein‐1 arms which cause the doublets to slide relative to one another. Previously, we demonstrated direct sliding of Tetrahymena ciliary axonemes by dark field light microscopy. In this paper, the results of such an experiment have been captured on a polylysine‐coated grid surface for whole‐mount electron microscopy. Images in which sliding between doublets has taken place can be identified. We conclude that doublets slide relative to one another with a constant polarity. To produce the observed displacement, the direction of the dynein‐1 arm force generation must be from base to tip, so that the doublet (n), to which the arms are attached, pushes the next doublet (n+ 1) toward the tip. In addition to the functional polarity, the dynein‐1 arms are found to have a structural polarity: they tilt toward the base when viewed along the edges of the A‐subfiber. A scheme is presented which reconciles the finding of a single polarity of active sliding with the geometry of microtubule tip displacement of bent cilia.
Dual Capacity for Nutrient Uptake in Tetrahymena. II. Role of the Two Systems in Vitamin Uptake
Authors: ORIAS EDUARDO , RASMUSSEN LEIF
Published: May 2007

SYNOPSIS Previously, we found that a mutant strain of Tetrahymena pyriformis without food vacuoles failed to grow unless the nutrient media were richly supplemented with vitamins and trace metals. Here we show that calcium folinate alone can replace the extra vitamin supplementation. The mutant requires ∼ 90‐fold higher concentrations of folinate than the wild‐type cells to give similar growth responses in a chemically defined medium. We infer that the food vacuole is an important route of uptake for this vitamin in the wild‐type cells. We found no difference between mutant and wild‐type cells in their requirements for nicotinic acid, pantothenic acid, riboflavin‐monophosphate, and pyridoxal. We infer that an extravacuolar route contributes importantly to uptake of these 4 compounds.
Isolation and Properties of Flagella of Trypanosomatids*
Authors: PEREIRA NEIZE M. , DE SOUZA WANDERLEY , MACHADO RAUL D. , CASTRO F. T. DE
Published: May 2007

SYNOPSIS. A procedure is described for the isolation of flagella of Crithidia fasciculata. Herpetomonas samuelpessoai and Leishmania tarentolae in a highly purified state and giving reasonably good yield. The 3 types of flagella give a similar electrophoretic pattern of proteins. It is shown that H. samuelpessoai and, to a lesser extent, C. fasciculata flagella confer protection against Trypanosoma cruzi infection.
Exacerbation of Experimental Trypanosoma cruzi Infection in Mice by Concomitant Malaria*
Authors: KRETTLI ANTONIANA URSINE
Published: May 2007

SYNOPSIS. The effect of malaria on the chronic phase of Chagas’disease was investigated in mice. The animals were given Plasmodium berghei‐infected red blood cells 2 to 12 months after their initial inoculation with trypomastigotes of 3 different strains of Trypanosoma cruzi (Y, CL and Gilmar). In all the experiments carried out with one of the strains (CL), a somewhat variable but always considerable percentage of mice (average 39%) relapsed in to the acute phase of Chagas’disease. This relapse was characterized by a significant increase in the number of circulating trypomastigotes. Recrudescence was observed also with a 2nd strain of T. cruzi (Gilmar), which is similar in many aspects to the CL strain, e.g. the morphology of blood stages, curve of parasitemia and susceptibility to antibodies in vitro. In mice whose chronic phase was induced by trypomastigotes of the Y strain, malaria infections did not induce a typical acute phase with high parasitemia by T. cruzi. Bloodstream forms of Y parasites differ from those of CL and Gilmar strains morphologically as well as immunologically, i.e. only the Y strain is easily agglutinated and partly inactivated by specific immune serum. In light of this and other known characteristics of the strains used in the present work, the author speculates on mechanisms which allow malaria infections selectively to suppress acquired host resistance to certain strains of T. cruzi.
Biological Interactions and the Realized Niche of Euplotes vannus from the Salt Marsh Aufwuchs
Authors: AILLLER WILLIAM A. , LEE JOHN J.
Published: May 2007

SYNOPSIS. Euplotes vannus, a hypotrich ciliate. grows well over broad ranges of temperature and salinity. It requires higher densities of food (> 1 × 104 cells/ml) for rapid reproduction than do the other herbivores, the foraminiferan Al‐logromia laticollaris (> 1 × 102 cells/ml), and the nematode Chromadorina germanica (∼ 1 × 103 cells/ml), to which it was compared. If food levels were initially very high (∼ 1 × 108 cells/ml) the ciliates reproduced rapidly and consumed the algae faster than it could reproduce. Some balance between the algae and the ciliates was achieved at initial algal concentrations of ∼ 1 × 105 cells/ml. In microcosm experiments at 25 C with equal numbers of C. germanica and A. laticollaris. E. vannus proved to be a very poor competitor; reaching only 20% of control levels when grow with C. germanica and only 13% when cultured with A. laticollaris. It was a better competitor in 2‐species microcosms, at lower temperatures, and when its ratio to the other species was initially higher.

The experimental evidence suggests that E. vannus is best adapted to being a migrating initial colonizer of fresh algal blooms.
Octadecenoic Fattv Acids and their Association with Hemolysis in Malaria
Authors: HOLZ G. G. , BEACH D. H. , SHERMAN I. W.
Published: May 2007

SYNOPSIS. Octadecenoic fatty acids have been implicated in prehemolytic and hemolytic phenomena associated with malaria. Oleic [18:1 (n‐9)] and cis‐vaccenic [18:1 (n‐7)] acids were found and quantified in the major neutral and phospholipids of the erythrocytes and plasmas of normal and Plasmodium lophurae‐infected ducks, and in the parasite itself. The octadecenoic fatty acids were elevated over normal values in the major phospholipid classes of infected erythrocytes, in the erythrocyte‐specific alkoxy phosphatidylethanolamine of infected erythrocytes, and in the plasma unesterified fatty acids, triacylglycerols, cholesterol esters and phosphatidylcholine of infected ducklings. Oleic acid was the major fatty acid of P. lophurae (33% total lipid fatty acids). Theoretical considerations of octadecenoic fatty acid modifications of erythrocyte membrane structure and function in malaria are discussed.
Subcellular Effects of Cytochalasin B and Dimethylsulfoxide on Paramecium aurelia*
Authors: SIBLEY JANE T. , PAUL MATTHEW D. , HANSON EARL D.
Published: May 2007

SYNOPSIS. Paramecium aurelia syngen 4, stock 57 (sensitive) cultivated in Cerophyl infusion were exposed to cytochalasin B CB and dimethylsulfoxide (DMSO), the solvent for CB, to distinguish between the effects of these agents on a cellular system. DMSO significantly inhibited survival, fission rate, [3H]leucine incorporation, and cell size. CB‐treated cells generally had slower division and poorer survival rates than cells exposed to the equivalent DMSO concentration, although the [3H]leucine incorporation was generally greater at the lower CB concentrations than for DMSO alone. As seen by electron microscopy and a new grycerination technic for observing polysomes, DMSO caused nuclear (nucleolar, chromatin) abnormalities as well as membrane degradation and polysomal breakdown; CB caused the formation of aberrant membrane structures and ribosomal tetramers, crystals, and tubes.
Additional Notes on the Coccidian Parasites of the Soft‐shell Turtle, Trionyx spiniferus Le Sueur, in Iowa, with a Description of Eimeria vesicostieda sp. n.*
Authors: WACHA RICHARD S. , CHRISTIANSEN JAMES L.
Published: May 2007

SYNOPSIS Oocysts of Eimeria dericksoni Roudabush, Eimeria mascoutini Wacha & Christiansen, and Eimeria vesicostieda sp. n. were isolated from the Spiny Soft‐shell Turtle, Trionyx spiniferus LeSueur, in Iowa. The sporulated oocysts of E. dericksoni are redescribed to include, for the first time, the dimensions of the sporocysts (6.0–8.5 × 3.0–5.0 μm) and the structural appearance of the Stieda body (thinly convex); the oocysts of E. vesicostieda are newly described as being thickwalled, narrowly ovoid to narrowly ellipsoid, measuring 22.0–25.5 × 16.5–20.5 μm. and having a polar granule, a sporocyst residuum, and a vesicle‐like Stieda body; the oocysts of E. mascoutini are documented photographically.
Geotactic Behavior of Chlamydomonas
Authors: BEAN BARRY
Published: May 2007

SYNOPSIS The normal negative geotaxis (motility oriented against gravity) of Chlamydomonas is an energy‐dependent response that requires coordinated flagellar activity. It is evident from quantitative assays that the rate of geotaxis is steady, and slow relative to the average swimming speed.

Geotaxis is inhibited when the horizontal swimming path is less than 200 μm, suggesting that normal geotactic reorientation maneuvers involve long gradual turns. Videomicrographic tracking of cells confirms that such turns are common. In contrast, contact‐reorientations generate random cell orientations. When collision frequencies increase, geotaxis in inhibited. The mechanism of normal geotactic orientation, then, depends on long slow reorientation maneuvers (from net downward to net upward vectors) that require hundreds of micrometers of free swimming space. Mechanisms of geotaxis that would require passive reorientation or sedimentation, or rapid active responding, are excluded.

Unusually dense populations sediment with atypical rapidity, probably due to formation of functionally aggregated subpopulations.

Sodium azide causes an inhibition of orientation behavior that is selective relative to its effects on general motility. Evidence presented suggests that active physiologic mechanisms for geotaxis should be reconsidered.
Monstrous Tetrahymena with Intraclonal Variation in Structure Produced by Hereditary Modification of Normal Cells
Authors: HJELM K. K.
Published: May 2007

SYNOPSIS Monstrous Tetrahymena pyriformis strain GL may be isolated after exposure of normal cells to numerous heat shocks, to flattening on agar or gelatin plates, or to viscous solutions of methyl cellulose. It is shown that in some cases the abnormalities are inherited and that this results in clones where the cells are different from each other and have various abnormalities with respect to cortical pattern, swimming and feeding behavior, and generation time. Furthermore, it is shown that these cells are produced rather than selected by the experimental treatments. Evidence is presented that growth without division is important for production of the abnormal organisms. The basis of the inheritance of the abnormalities is discussed.
Ciliary Membranes and Mating Substances in Paramecium caudatum
Authors: WATANABE TSUYOSHI
Published: May 2007

SYNOPSIS Cilia detached from mating reactive cells of Paramecium caudatum were fractionated for the purpose of identifying the structural component bearing mating substances. Purified axoneme fractions had no mating reactivity. The membrane fraction obtained by dialyzing against a solution of Tris‐EDTA (0.1 mm EDTA, 1 mm Tris‐HCI, pH 7.6) and 0.6 m KCI, and then by centrifuging over 40% (w/v) sucrose was strongly reactive. No mating reactivity was detected in the soluble fractions containing axonemal and matrix proteins. The results indicate that the mating substances in active from are localized only on the ciliary membranes.