bluuebunny/crossref_metadata_2025 huggingface dataset:
Density of Parasites in Various Organs and the Relation to Numbers of Trypomastigotes in the Blood during Acute Infections of Trypanosoma cruzi in Mice*
Authors: HANSON WILLIAM L. , ROBERSON EDWARD L.
Published: May 2007

SYNOPSIS

Quantitative methods were used to (a) determine the density of Trypanosoma cruzi in organs of CF1 mice following intraperitoneal inoculation of 50,000 trypomastigotes of a Brazil strain of T. cruzi and (b) study the relation of the numbers of these intracellular stages to the numbers of trypomastigotes in the blood. Tissue stages (predominantly amastigotes) in heart, skeletal muscle (triceps), diaphragm, cerebrum, cerebellum, and musculature of stomach, duodenum, esophagus, jejunum, cecum, and rectum increased in numbers during the 1st 3 weeks of infection, reached maximum density 21–28 days after inoculation and subsequently declined in numbers until mice were histologically negative for intracellular parasites by 30–40 days. The density of tissue stages in the urinary bladder, uterine body, and ileum was similar with the exception that maximum numbers of parasites were observed slightly earlier at 15 days.

The greatest density of intracellular stages was seen in heart, urinary bladder, diaphragm, and triceps muscle where mean counts of 44.6–60.0 × 106 parasites/cc of muscle were recorded while maximum density of parasites in the uterine body, cerebrum, stomach, cerebellum, duodenum, esophagus, jejunum, ileum, cecum, and rectum was 13.0 × 106/cc of muscle or less. Amastigotes were not observed in sections of lymph node, thymus, salivary glands, liver, spleen, or kidney and only a single pseudocyst containing 5 amastigotes was seen in lung. With the exception of the brain and lung, intracellular parasites were located exclusively in the musculature.

Trypomastigotes in the blood increased during the 1st 3 weeks of infection, reached maximum numbers 21–28 days after initiation of infection, and subsequently decreased until by 30–40 days parasites were observed only rarely in the blood of a few animals. Thus generally close correlation was noted between the numbers of intracellular stages of T. cruzi in the organs and trypomastigotes in the blood throughout acute Chagas’ disease in mice as evidenced by the concomitant increase in numbers of both stages, the coincidence of days of maximum parasite levels, and the simultaneous decline in numbers of both stages.

The mean number of parasites/pseudocyst section varied in the organs studied. Of the 15 positive organs studied, the pseudocyst sections in skeletal muscle contained the highest mean number of parasites (64.3 parasites/pseudocyst section) and those pseudocyst sections seen in the musculature of the small intestine contained the lowest mean number (5.5–6.8 parasites/pseudocyst section respectively in ileum and jejunum).

Serial sections of skeletal muscle, heart, urinary bladder, and stomach revealed the largest pseudocysts in skeletal muscle while those in the musculature of the urinary bladder were the smallest.
Kinetoplast DNA of Crithidia*†
Authors: WOLSTENHOLME DAVID R. , RENGER HARTMUT C. , MANNING JERRY E. , FOUTS DAVID L.
Published: May 2007

SYNOPSIS. The results of physiochemical and electron microscope studies on the structure of the kinetoplast DNA of Crithidia are discussed. The molecular weight of isolated kinetoplast DNA is approximately 41 × 109 daltons. The basic unit of organization of this DNA is a covalently closed circular molecule 0.8 μm in contour length (molecular weight 1.54 × 106 daltons). An average of 33 such circles are held together in a group by topological interlocking of each circle with a large number of other circles in the group. An average of 804 groups are held together into a structure termed an association. A group of circles is attached to several adjacent groups. This is accomplished by 1 or more circles each interlocking with many circles in 2 (but never more) of the groups. The groups of circles are arranged in such a way that the association, comprising about 27,000 circles, has a topologically 2‐dimensional form. A model is presented for the in situ arrangement of the kinetoplast DNA association. Data which we have obtained is consistent with the view that all of the circular molecules of kinetoplast DNA of one organism carry the same genetic information. The transcription product is a single RNA molecule of approximately the size of a single circular DNA molecule. From studies involving density shift experiments using deuterium oxide, buoyant density ultracentrifugation and electron microscopy we have determined the following concerning replication of kinetoplast DNA: (a) doubling of the kinetoplast DNA results from the replication of each circular molecule rather than from extensive replication of a small number of circular molecules; (b) replication of kinetoplast DNA is a semi‐conservative rather than a conservative process and there is recombination at an undefined time during the cell cycle; (c) a portion of a kinetoplast DNA association is in the form of long linear molecules during the replicative phase of that association.
Cryptosporidium anserinum sp. n. (Sporozoa) in a Domestic Goose Anser anser L., from Iowa
Authors: PROCTOR S. J. , KEMP R. L.
Published: May 2007

SYNOPSIS. Cryptosporidium anserinum sp. n. is described in the large intestinal mucosa of a domestic goose, Anser anser L., from Iowa. Ultrastructural studies revealed schizonts containing 4 merozoites and macrogametes and schizonts with characteristic attachment zones and double membranes. The only lesion associated with infection was shortening of the intestinal microvilli.
Quantitative Ultrastructural Differences between Strains of the Trypanosoma brucei Subgroup During Transformation in Blood*
Authors: BÖHRINGER S. , HECKER H.
Published: May 2007

SYNOPSIS. Differences in the relative and absolute cell organization between strains of the Trypanosoma brucei subgroup were studied during the transformation from slender to stumpy bloodforms. Two pleomorphic and 1 monomorphic T. b. brucei, and 1 pleomorphic T. b. rhodesiense strains were investigated. Volume densities, surface densities and surface to volume ratios showed barely significant differences between the 2 pleomorphic T. b. brucei strains; absolute parameters, however, differ markedly between all the strains investigated. Only the relative parameters of the mitochondrion show notable differences between T. b. brucei and T. b. rhodesiense examined here. During the transformation from slender to stumpy forms the enlargement of the mitochondrial volume in T. b. brucei is achieved by an increase in width of the mitochondrial tube and in T. b. rhodesiense by the formation of a more elaborate network. The ratio of the inner mitochondrial membrane surface area to the mitochondrial matrix volume showed no significant change in all 3 pleomorphic strains examined. Because of their morphometric similarity to slender forms of pleomorphic T. b. brucei strains, it can be assumed that the monomorphic trypanosomes correspond morphologically to slender trypanosomes. Neither pleomorphism nor strain specificity have a significant influence on the relative amount of “vesicles” and lipid inclusions.
Feeding Mechanisms of Babesia equi
Authors: FRERICHS WAYNE M. , HOLBROOK A. A.
Published: May 2007

SYNOPSIS. Electron microscope and time lapse, phase contrast cinematography studies on Babesia equi organisms within equine red blood cells revealed that this hemoprotozoon has two organelles possibly involved with ingestion of nutrients: a cytostome that takes in hemoglobin from the host cell and a tubule that extends from the main body of the parasite through the erythrocyte to the blood plasma and appears to ingest plasma during periods of rapid growth and development.
Studies of Membrane Formation in Tetrahymena pyriformis. VIII. On the Origin of Membranes Surrounding Food Vacuoles*†
Authors: WEIDENBACH ANNITA L. S. , THOMPSON GUY A.
Published: May 2007

SYNOPSIS. A procedure was devised for the isolation of purified food vacuoles from Tetrahymena pyriformis fed particles of ferric oxide. Phospholipids extracted from vacuolar membranes were more similar in composition to the lipids of microsomes than to lipids of whole cells, cilia or post‐microsomal supernatant. Fractionation of cells grown in the presence of [14C]palmitic acid or [32P]inorganic phosphate also revealed similarities in the specific radioactivities of microsomes and vacuolar membranes. The data suggested that vacuolar membranes arise from a pool of cytoplasmic membranes.
Isolation of an Unusually Stable Cis‐Isomer of Alloxanthin from a Bleached Autolysed Culture of Chroomonas salina Grown Photoheterotrophically on Glycerol. Observations on Cis‐Trans Isomerization of Alloxanthin
Authors: CHENG J. Y. , DON‐PAUL M. , ANTIA N. J.
Published: May 2007

SYNOPSIS. A new carotenoid, manixanthin, was isolated from a bleached, autolysed culture of the marine cryptomonad Chroomonas salina grown on glycerol in light, after the culture showed disappearance of the chlorophylls and carotenoids normally produced. Manixanthin lacked carbonyl, ester, and epoxy groups in chemical tests, whilst its spectroscopic properties indicated a conjugated nonaene chromophore. In its chromatographic mobility, manixanthin closely resembled alloxanthin, the major normal xanthophyll of the cryptomonad. The iodine‐catalysed photostereomutation of manixanthin produced the same equilibrium mixture of cis‐isomers as that given by similar treatment of alloxanthin. This mixture of isomers completely lacked the all‐trans alloxanthin and contained ∼60% manixanthin. It was concluded that manixanthin is an unusually stable cis‐isomer of alloxanthin, and is presumably produced in the culture medium by the action of light on alloxanthin released by autolysed cells of the cryptomonad. The unusual stability of manixanthin relative to alloxanthin was investigated by effecting partial stereoisomerizations under conditions using either of heat, light, or iodine, and evidence was obtained for a series of at least 10 isomers with a trend of stability increase from alloxanthin to manixanthin. It was inferred that manixanthin may be 9,9′‐dicis‐alloxanthin.
Three Centuries of Protozoology: A Brief Tribute to its Founding Father, A. van Leeuwenhoek of Delft*
Authors: CORLISS† JOHN O.
Published: May 2007

SYNOPSIS. It was exactly 300 years ago this month (August 1974) that the 17th century modest draper from Delft, Holland—Antony van Leeuwenhoek—discovered protozoa. Describing them, often with amazing accuracy considering the optical equipment he was using (simply a home‐made “glorified”hand lens), in letters to the Royal Society of London, he established himself, certainly, as the founding father of protozoology. It is particularly appropriate for an assemblage of protozoologists to pay homage to this intrepid “philosopher in little things,”a man with an insatiable curiosity about his wee animalcules, on the tricentenary of his discovery of them, since it was an event of such long‐lasting significance.
Protein Uptake and Digestion in Bloodstream and Culture Forms of Trypanosoma brucei*
Authors: LANGRETH SUSAN G. , BALBER ANDREW E.
Published: May 2007

SYNOPSIS. The mechanisms of ferritin uptake and digestion differ in bloodstream and culture forms of Trypanosoma brucei. Ferritin enters bloodstream forms from the flagellar pocket by pinocytosis in large spiny‐coated vesicles. These vesicles become continuous with straight tubular extensions of a complex, mostly tubular, collecting membrane system where ferritin is concentrated. From the collecting membrane system the tracer enters large digestive vacuoles. Small spiny‐coated vesicles, which never contain ferritin, are found in the Golgi region, fusing with the collecting membrane system, and around the flagellar pocket. Acid phosphatase activity is present in some small spiny‐coated vesicles which may represent primary lysosomes. This enzymic activity is also found in the flagellar pocket, pinocytotic vesicles, the collecting membrane system, the Golgi (mature face), and digestive vacuoles of bloodstream forms. About 50% of the acid phosphatase activity of blood forms is latent. The remaining nonlatent activity is firmly cell‐associated and probably represents activity in the flagellar pocket. The structures involved in ferritin uptake and digestion are larger and more active in the short stumpy than in the long slender bloodstream forms. The short stumpy forms also have more autophagic vacuoles. No pinocytotic large, spiny‐coated vesicles or Golgi‐derived, small spiny‐coated vesicles are seen in culture forms. Ferritin leaves the flagellar pocket of these forms and enters small smooth cisternae located just beneath bulges in the pocket membrane. The tracer then passes through a cisternal collecting membrane network, where it is concentrated, and then into multivesicular bodies. In the culture forms, acid phosphatase activity is localized in the cisternal system, multivesicular bodies, the Golgi (mature face), and small vesicles in the Golgi and cisternal regions. The flagellar pocket has no acid phosphatase activity, and almost all the activity is latent in these forms. The culture forms do not release acid phosphatase into culture medium during 4 days growth. Uptake of ferritin by all forms is almost completely inhibited by low temperature. These differences among the long slender and short stumpy bloodstream forms and culture forms are undoubtedly adaptive and reflect different needs of the parasite in different life cycle stages.
Ultrastructure and Vacuolar Movements in the Free‐Living Diplomonad Trepomonas agilis Klebs*
Authors: EYDEN BRIAN P. , VICKERMAN KEITH
Published: May 2007

SYNOPSIS. The structure of Trepomonas agilis communis Klebs is described from light and electron microscope observations on 2 clone isolates of the organism. The surface membrane shows marked differentiation into an extremely thick (16 nm) symmetric membrane which covers the greater part of the body, and a thinner (∼ 10–12 nm) asymmetric membrane which lines the 2 lateral oral grooves and the posterior channel connecting them; a similar asymmetric membrane covers the flagella. Thorium dioxide staining suggests a denser distribution of acidic carbohydrate groups on the asymmetric membrane. The pathways of cytoplasmic streaming observed in the living flagellate coincide with those of microtubule bands arising close to the flagellar basal bodies and it is suggested that the bands play an orienting role in the streaming of food vacuoles. The contractile vacuole undergoes diastole in the anterior (postnuclear) cytoplasm, and is formed by coalescence of smaller vesicles. At systole the entire vacuole migrates to the posterior extremity to discharge into the posterior channel; the route of exit lacks guiding structural elements. Features of the flagellate's physiology and organization are discussed in relation to the observed lack of mitochondria, microbodies and Golgi apparatus in diplomonads.
ATPase Activity in Flagella from Euglena gracilis. Localization of the Enzyme and Effects of Detergents*
Authors: PICCINNI ESTER , ALBERGONI VINCENZO , COPPELLOTTI OLIMPIA
Published: May 2007

SYNOPSIS. The biochemical effects of some detergents on the ATPase activity of isolated flagella from Euglena gracilis are related to morphologic obliterations induced by those detergents. Enzymic activity can be localized by electron microscopy along the microtubules and also on the paraflagellar rod. The nonionic detergent digitonin solubilizes the enzyme linked to dyneinic arms, whereas the activity linked to residual structures appears enhanced. These results support the hypothesis that the paraflagellar rod may be a structure actively related to the motility of this type of flagellum.
Response of Chlamydomonas to Temperature Change
Authors: MAJIMA TOSHIKAZU , OOSAWA FUMIO
Published: May 2007

SYNOPSIS. Response of Chlamydomonas to temperature change was investigated. When the temperature of the medium was suddenly increased (decreased) the abrupt velocity rise (drop) was observed. This abrupt velocity change was induced immediately after the temperature change. Then, the high (low) level of the velocity was maintained for a few minutes. Finally the velocity decreased (increased), tending to a stationary level at the new temperature with the decay time of a few minutes. The rate of the temperature change determined the magnitude of response. The threshold value was found in the rate of the temperature change to produce the transient change of the velocity. It was ∼ 0.2 C/sec.
Interstitial Protozoa and Algae of Louisiana Salt Marshes
Authors: ELLIOTT PRISCILLA BROWN , BAMFORTH STUART S.
Published: May 2007

SYNOPSIS. The majority of Louisiana salt marshes consists of stagnant pools among a vegetation of Spartina spp. and Distichlis spicata. The sediments constitute a “sulphide biome,'’with Eh values reaching to –350 mV. The 200 interstitial ciliate species had definite stratification. Generally, algivores and omnivores occurred in the upper, and bactivores in the lower layers of the sediments. Compaction of particles prevented the flexible and large ciliates from inhabiting the lower layers, while Eh below –200 mV limited the distribution of some species but favored certain bactivores. The pH/Eh range and the abundance of nutrients in the sulfide biome provide habitable conditions for all the major groups of microflora. These, in turn, support nutritionally diverse predatory ciliate populations.
Distribution of Pirhemocyton Chatton & Blanc and other, Possibly Related, Infections of Poikilotherms
Authors: JOHNSTON M. R. L.
Published: May 2007

SYNOPSIS. Data for host and geographic distribution are listed for Pirhemocyton and for apparently similar infections of poikilothermic vertebrates. The list was compiled from published accounts of Pirhemocyton, Toddia, Cytamoeba, Bertarellia, Piscine erythrocytic necrosis, Immanoplasma, Haematractidium, Sauroplasma, Sauromella, Serpentoplasma, Tunetella, Haemohormidium and unnamed infections. New records are included for Pirhemocyton and Haematractidium. The probability that some may be viruses and not protozoa is discussed; Haematractidium is shown by electron microscopy to be a eukaryote whereas Immanoplasma is not a eukaryote.
Dihydrofolate Reductase from Eimeria tenella: Rationalization of Chemotherapeutic Efficacy of Pyrimethamine
Authors: WANG CHING CHUNG , STOTISH RONALD L. , POE MARTIN
Published: May 2007

SYNOPSIS. Dihydrofolate reductase activity of 0.2 nmole of dihydrofolate reduced/min/mg protein was detected in crude extracts of unsporulated oocysts of Eimeria tenella. The enzyme was purified by a combination of affinity and ion‐exchange chromatography. Its molecular weight was estimated as 240,000 daltons. An anticoccidial drug pyrimethamine is a potent inhibitor of the activity of E. tenella dihydrofolate reductase (Kt= 3 nM), but it is less effective an inhibitor of dihydrofolate reductase from chicken liver. This difference may explain the in vivo therapeutic action of pyrimethamine against Coccidia.
Effect of the Antiphagocytic Agent Cytochalasin B on Macrophage Invasion by Leishmania mexicana Promastigotes and Trypanosoma cruzi Epimastigotes*
Authors: ALEXANDER JAMES
Published: May 2007

SYNOPSIS

Unstimulated mouse peritoneal exudate cells were cultured on coverslips in Medium 199 containing 10% (v/v) calf serum. Cytochalasin B dissolved in dimethyl sulphoxide (DMSO) and diluted in Medium 199 was added to cultures to give final concentrations of 1, 5 and 10 μg/ml. Equal numbers of Leishmania mexicana promastigotes, Trypanosoma cruzi epimastigotes and sheep red cells were added to 24 hr cultures incubated at 37 C. The macrophage monolayers were fixed and stained at various time intervals. L. mexicana promastigotes and sheep red blood cells were found to attach to macrophages in the presence of the drug but did not enter the cells. When the medium containing the Cytochalasin was replaced with normal medium phagocytosis of the adherent parasites and red cells followed rapidly. T. cruzi epimastigotes were found inside macrophages in both drug‐treated and drug‐free cultures although the number found to be intracellular in the latter was significantly greater. This study suggests that L. mexicana promastigotes enter macrophages by being phagocytosed, whereas T. cruzi epimastigotes can actively penetrate these cells.
The Immobilization Antigen of Paramecium aurelia is a Single Polypeptide Chain
Authors: HANSMA HELEN G.
Published: May 2007

SYNOPSIS

The immobilization antigen (i‐antigen) fraction of Paramecium aurelia syngen 4 is shown to contain a protease that is activated by mercaptoethanol. After the protease has been heat‐inactivated, the molecular weight of the i‐antigen (∼250,000 daltons) cannot be decreased by mercaptoethanol treatment. It is demonstrated that the i‐antigen is a single polypeptide chain. Reasons are also given why low molecular weight subunits were previously reported by other authors.
Does a Histidine‐Rich Protein from Plasmodium lophurae Have a Function in Merozoite Penetration?*
Authors: KILEJIAN ARAXIE
Published: May 2007

SYNOPSIS. Autoradiography was used to localize the distribution of l‐[3H]histidine incorporated in vitro by developing segmenters of Plasmodium lophurae. Under conditions used for the visualization of high specific activity loci, radioactivity appeared associated mainly with the histidine‐rich protein of cytoplasmic granules as well as with rhoptries and micronemes of merozoites. The isolated histidine‐rich protein caused agglutination of erythrocytes and increased their osmotic fragility. Based on the observed evidence suggesting the presence of this histidine‐rich protein in the polar organelles of merozoites and its reactivity with erythrocyte membranes, the hypothesis that such a protein may have a function in the penetration of merozoites is proposed.
Comparative Ultrastructure and Systematics of the Colpodida. Structural Conservatism Hypothesis and a Description of Colpoda steinii Maupas*
Authors: LYNN DENIS H.
Published: May 2007

SYNOPSIS. A brief review of the comparative ultrastructure of several major taxa of ciliated protozoa has disclosed a relationship between the level of biologic organization and the supposed conservatism of cellular structures. The structural conservatism hypothesis proposes that conservation of structure through time is inversely related to the level of biologic organization. If true, this hypothesis will provide a rationale for future systematic investigation of ciliates. Comparative analysis of the fine structure of species of the ciliate order Colpodida will be used as a detailed test of the structural conservatism hypothesis. In this report, the ultrastructure of Colpoda steinii Maupas is described and compared to previous descriptions of colpodids. A new terminology for ciliate ultrastructures is proposed which avoids the ambiguities of the present, taxonomically oriented one.
The Fine Structure of the Colonial Colorless Flagellates Rhipidodendron splendidum Stein and Spongomonas uvella Stein with Special Reference to the Flagellar Apparatus
Authors: HIBBERD DAVID J.
Published: May 2007

SYNOPSIS. The cell structure of the colorless colonial flagellates Rhipidodendron splendidum Stein and Spongomonas uvella Stein has been examined by electron microscopy to assertain their phylogenetic affinities. The cylindrical cells of R. splendidum have 2 smooth flagella of equal length, an asymmetrical flagellar pocket supported by microtubules, and a curved pit between the latter and an anterior prolongation of the cell. The matrix of the branched tubes comprising the fanshaped colony is composed largely of dense spherules which are produced in special cytoplasmic vesicles some of which contain symbiotic bacteria. The anterior nucleus has a flattened sac pressed closely against its posterior end. The sac has a long tail extending deep into the cytoplasm, a single bounding membrane and homogeneous contents. Several types of vesicle are described but food vacuoles and contractile vacuoles could not be positively identified. A kinetoplast mitochondrion is not present. The various cross‐banded, microtubular and amorphous components of the complex and highly asymmetrical flagellar root system are described in detail and a 3‐dimensional reconstruction is provided.

The ovoid cells of S. uvella are basically similar to those of R. splendidum; though a nuclear sac is missing, there are some detailed differences in the structure of the flagellar root system, and bacteria are never present in the vesicles producing the matrix granules. Notwithstanding much similarity, Rhipidodendron is not combined with Spongomonas because of the basic difference in colony structure.

The possible relationships of R. splendidum and S. uvella with other groups are examined and it is concluded that they cannot be considered as colorless chrysomonads as previously thought or considered to be related to any of the other orders comprising the class Phytomastigophorea. They do not, however, appear to be related to any of the orders at present comprising the Zoomastigophorea.
The Attraction of Trypanosoma cruzi to Vertebrate Cells In Vitro
Authors: DVORAK JAMES A. , HOWE CHRISTINE L.
Published: May 2007

SYNOPSIS. A video technic is described that permits a quantification of the degree of attraction of Trypanosoma cruzi trypomastigotes to vertebrate cells in vitro. Bovine embryo skeletal muscle cells (BESM), HeLa cells and Vero cells all attract a myotropic strain of T. cruzi trypomastigotes. BESM cells, however, are 2‐fold more attractive to trypomastigotes than HeLa cells and 10‐fold more attractive than Vero cells. Heat‐inactivation of BESM cells abolishes their ability to respire and also to attract T. cruzi trypomastigotes. As there is no difference in the endogenous oxygen consumption between BESM, HeLa, and Vero cells, it is unlikely that differences in the attraction of trypomastigotes to the 3 cell types are due to variations in the magnitude of pO2 or pCO2 gradients in the milieu around the cells.
Feline Toxoplasmosis from Acutely Infected Mice and the Development of Toxoplasma Cysts*
Authors: DUBEY J. P. , FRENKEL J. K.
Published: May 2007

SYNOPSIS. The development of Toxoplasma cysts was studied in mice inoculated with tachyzoites by several routes. After 1–30 days of infection, murine tissues were examined microscopically, and portions or whole carcasses were fed to mice and cats. The feces of the cats were examined for oocyst shedding.

Cyst‐like structures containing distinct PAS‐positive granules were first seen after 3 days of infection with tachyzoites, and became numerous by 6 days. Argyrophilic walls were first seen after 6 days, and became numerous by 16 days of infection with tachyzoites.

Prepatent periods to oocyst shedding (PPO) were either “short” (3–10 days) or “long” (19–48 days). The “short” PPO was found only in cats that had ingested mice infected for 3 days or longer, and was related to the development of PAS‐positive granules in T. gondii, and to high, 60–100%, oral infectivity rates for cats. The “long” PPO followed the ingestion of mice infected for only 1–2 days, and was related to tachyzoites without distinct PAS‐positive granules and low, 32% or less, infectivity for cats. The “long” PPO followed also the ingestion of oocysts and the parenteral inoculation of tachyzoites, bradyzoites, or sporozoites.

Using the “short” PPO as a criterion for detecting cysts in tissues, it was shown that (a) numerous cysts developed in mice 5 days after inoculation with tachyzoites, 7–9 days after inoculation with cysts, and 9–10 days after inoculation with oocysts, and (b) cysts developed faster and more frequently in the brain and muscle than in lungs, liver, spleen, and kidneys of mice inoculated with tachyzoites.
Enzymes of Carbohydrate Metabolism in Four Human Species of Leishmania: A Comparative Survey*
Authors: MARTIN ELMER , SIMON MICHAEL W. , SCHAEFER FRANK W. , MUKKADA ANTONY J.
Published: May 2007

SYNOPSIS. The occurrence and levels of activity of various enzymes of carbohydrate catabolism in culture forms (promastigotes) of 4 human species of Leishmania (L. brasiliensis, L. donovani, L. mexicana, and L. tropica) were compared. These organisms possess enzymes of the Embden‐Meyerhof pathway but lack lactate dehydrogenase. No evidence could be found for the production of lactic acid by growing cultures and lactic acid could not be detected either in cell‐free preparations or after incubation of cell‐free extracts with pyruvate and NADH under appropriate conditions. All 4 species possess α‐glycerophosphate dehydrogenase and α‐glycerophosphate phosphatase which together could regenerate NAD, thus compensating for the absence of lactate dehydrogenase. The oxidative and nonoxidative reactions of the hexose monophosphate pathway are present in all 4 species. Cell‐free extracts have pyruvate dehydrogenase activity which allows the entry of pyruvate into and its subsequent oxidation through the tricarboxylic acid cycle. All enzymes of this cycle, including a thiamine pyrophosphate dependent α‐ketoglutarate dehydrogenase are present. Both NAD and NADP‐linked malate dehydrogenase activities are present. The isocitrate dehydrogenase is NADP specific. There is an active glutamate dehydrogenase which could compete with α‐ketoglutarate dehydrogenase for the common substrate (α‐ketoglutarate). Replenishment of C4 acids is accomplished by heterotrophic CO2 fixation catalyzed by pyruvate carboxylase. All 4 species have high levels of NADH oxidase activity. Several enzymes thus far not found in any species of Leishmania have been demonstrated. These are: phosphoglucose isomerase, triose phosphate isomerase, fructose‐1, 6‐diphosphatase, 3‐phosphoglycerate kinase, enolase, α‐glycerophosphate dehydrogenase, α‐glycerophosphate phosphatase, pyruvate dehydrogenase complex, citrate synthase, aconitase, α‐ketoglutarate dehydrogenase, glutamate dehydrogenase, and NADH oxidase.
Phylogenetic Origin of the Chloroplast*†
Authors: BUETOW D. E.
Published: May 2007

SYNOPSIS. The 16S ribosomal RNA of the chloroplast of Euglena gracilis strain Z has been characterized in terms of its 2‐dimensional electrophoretic “fingerprint” (T1 ribonuclease). Over 100 spots were resolved on the “fingerprint” and each spot was characterized as to which RNA oligonucleotide fragment(s) it contained. When compared to similar analyses of prokaryotic 16S rRNAs and eukaryotic cytoplasmic 18S rRNAs, the chloroplast 16S rRNA was a typically prokaryotic RNA, but bore little if any relationship to eukaryotic 18S rRNAs. Therefore, the cistrons for chloroplast 16S rRNA are related to the equivalent prokaryotic cistrons, but, apparently, are not related to the equivalent eukaryotic cistrons. Among the organisms available for comparison, the Euglena chloroplast 16S rRNA appears most closely related to the 16S rRNA of the eukaryote, Porphyridium cruentum (a red alga), and at least distantly related to the 16S rRNAs of the blue‐green algae and perhaps also to the bacilli.
Fine Structure of the Schizont Stage of the Testate Marine Ameba, Trichosphaerium sp.*
Authors: SCHUSTER F. L.
Published: May 2007

SYNOPSIS. The schizont stage of 3 strains of the testate marine ameba, Trichosphaerium sp., was examined in the transmission electron microscope. The cytoplasm of this multinucleate organism contained the usual organelles; the test was covered by spicules. Pseudopodial types included broad ectoplasmic lobopods that assisted in locomotion, and thin dactylopods that probably had a sensory function. Nuclear division, observed in one of the strains, was characterized by an intact nuclear envelope (at least through anaphase), and the absence of centrioles. Nuclei in an ameba divided synchronously. An unusual intranuclear body of unknown function was found in another of the strains examined.
Strain‐Dependent Thermosensitivity Influencing Intracellular Differentiation of Trypanosoma cruzi in Cell Culture*
Authors: BRENER Z. , GOLGHER R. , BERTELLI M. S. , TEIXEIRA J. A.
Published: May 2007

SYNOPSIS. Temperature strongly influenced morphogenesis of intracellular trypomastigotes in cell culture infected with 2 different strains of T. cruzi. With the Gilmar strain the amastigote‐to‐trypomastigote differentiation readily occurred at 33 and 37 C, whereas with the CL strain differentiation took place at 33 C but was inhibited at 37 C. The possibility of this selective thermosensitivity resulting from mutational adaptation of the parasite is discussed.
Hydrolytic Enzymes of Euglena gracilis: Characterization and Activity as a Function of Culture Age and Carbon Deprivation*†
Authors: BAKER WILLIAM B. , BUETOW D. E.
Published: May 2007

SYNOPSIS. Optimal assay conditions are described for 8 hydrolases of Euglena gracilis var. bacillaris, SM‐L1 (streptomycinbleached) strain, 7 of which have an acid pH‐optimum. Acid phosphatase, β‐galactosidase, β‐glucosidase, β‐fucosidase, cathepsin D, RNase, DNase, and an esterase are active in cell homogenates. Amylase has very low activity, and β‐glucuronidase, arylsulfatase, β, N‐acetyl‐glucosaminidase, α‐fucosidase, and α‐ and β‐mannosidase are inactive.

Hydrolase activity increases as a culture proceeds from the midexponential to the late stationary‐phase of growth, being most pronounced in the case of β‐glucosidase. In cultures deprived of a utilizable carbon source, the specific activities of the hydrolases (per mg total protein or dry weight) increase. When expressed on a per cell basis, however, the activities of DNase decrease while those of β‐galactosidase, cathepsin D, and RNase increase. The hydrolases appear to be involved in the adaptation of Euglena to the metabolic demands imposed by different conditions of growth.
An Ultrastructural Investigation of 180°‐Rotated Ciliary Meridians in Tetrahymena pyriformis*
Authors: NG STEPHEN F. , WILLIAMS RUTH JAECKEL
Published: May 2007

SYNOPSIS. An ultrastructural investigation has been carried out on 180°‐rotated ciliary meridians (inverted meridians) in Tetrahymena pyriformis temperature‐sensitive mutant (molb/molb), syngen 1, strain B. The longitudinal, transverse and postciliary microtubular bands, the kinetodesmal fiber, and the parasomal sac, are shown to be disposed at a 180° angle to their normal positions or orientations. Other abnormalities are as folows: the first 2 basal bodies of the inverted meridian fail to organize into “couplets” and the inverted meridian intrudes into the anterior pole region; an extra longitudinal microtubular band is found in one of the cell lines.
The Role of Microtubules in Macronuclear Division of Blepharisma*
Authors: JENKINS ROBERT A.
Published: May 2007

SYNOPSIS. The macronucleus of the heterotrich ciliate Blepharisma undergoes a spectacular change in form in preparation for its division. The elongation phase of this cycle has been examined by light and electron microscopy. Coincident with elongation, microtubules appear closely applied to the outer surface of the macronucleus and parallel to the direction of elongation, and disappear as elongation is completed. It is demonstrated that the antimitotic drugs colchicine and podophyllotoxin reversibly block macronuclear elongation but do not entirely inhibit morphogenetic events including cell division. The failure of colchicine‐treated macronuclei to begin or continue elongation is correlated with the prevention of formation, disruption, and/or disorientation of the extranuclear microtubules.
Effects of Dimethyl Sulfoxide on Tetrahymena pyriformis GL. Fine Structural Changes and Their Reversibility*
Authors: NILSSON JYTTE R.
Published: May 2007

SYNOPSIS. Fine‐structural changes are induced in Tetrahymena by exposure to 7.5% dimethyl sulfoxide (DMSO) in the presence of growth medium. Some of these changes (nucleolar, mitochondrial, peroxisomal) resemble those seen during starvation, in agreement with the previously reported inhibitory effect of DMSO on food‐vacuole formation; however, changes such as helical formations of polyribosomes indicate additional internal actions of the reagent. The effects vary to some extent within the same group of cells, suggesting that sensitivity to the reagent may differ with the stage in the cell cycle. The structural changes induced by a 1‐hr exposure to DMSO are reversible, but recovery of the cells after removal of the reagent is slower than that seen after starvation. The observations suggest that the recovery is associated with renewed synthesis.
Temperature Effect on the Photo‐Accumulation and Phobic Response of Volvox aureus*
Authors: SAKAGUCHI HIRONOBU , TAWADA KATSUHISA
Published: May 2007

SYNOPSIS. The effect of temperature on photoaccumulation and photophobic response of Volvox aureus were studied. The algae exhibited positive photoaccumulation at room temperature and negative at low temperature. When stimulated with light of intermediate intensiy (∼ 5 × 103 lux), the phobic response of the algae consisted of a decrease in the frequency or the cessation of flagellar movement in the anterior cells. At room temperature, an increase in light intensity elicited the phobic response, whereas at low temperature a decrease in light intensity was the effective stimulus. The phobic response lasted only a few seconds. The positive and negative photoaccumulations of the algae could be explained by the brief cessation of flagellar movement in the anterior cells, elicited by an increase of stimulus light at room temperature or a decrease of stimulus at low temperature.
Phosphofructokinase of Leishmania donovani and Leishmania braziliensis and its Role in Glycolysis*
Authors: BERENS RANDOLPH L. , MARR J. JOSEPH
Published: May 2007

SYNOPSIS. It was shown in an investigation of the phosphofructokinases of Leishmania donovani and Leishmania braziliensis that both enzymes are similar to that of Crithidia fasciculata. Although the enzymes are allosteric with respect to their substrates and require AMP for activation, there is no influence by other heterotropic modifiers. The Mg2+‐ATP chelate activates these enzymes in a first order process and they can be inhibited by free ATP. The inhibition is reversed by the activator, AMP, in a competitive manner. The requirement for the nucleotide in L. donovani can be eliminated by decreasing the pH.

The data indicate that phosphofructokinase, a pivotal enzyme in glycolysis for most organisms, probably does not play an important role in glycolysis in Leishmania.
An Approach to Quantitative Nutrition of Phytoplankton
Authors: DROOP M. R.
Published: May 2007

SYNOPSIS. An outline is given of the 2‐compartment model of algal growth developed by the author over the last decade, The model, as fully developed, claims to be able to handle simultaneously as many nutrients and organisms as desired in an environment of changing inputs and outputs.
The Nutrition of the Freshwater Dinoflagellate Ceratium hirundinella*
Authors: BRUNO STEPHEN F. , MCLAUGHLIN JOHN J. A.
Published: May 2007

SYNOPSIS.

A defined medium was devised for a freshwater isolate of the dinoflagellate Ceratium hirundinella. Highest cell yields were produced at 7,700–10,000 lux. The optimum pH range was between 7.0 and 7.5: the optimum temperature 21°C. Ceralium hirundinella tolerated a wide range (per liter) of Ca (0.1–100 mg) and Mg (0.1–50 mg) ion concentrations. The optimum range for growth was 20–30 rns Ca and 10–30 mg Mg. Cells cultured in media lacking Ca often became teratological yet motilp and viable. Variations in the Ca:Mg ratio had little effect on cell yield if the sum of the concentrations of the 2 ions remained the same. Organic as well as inorganic sources of N and P were utilized. NH4 sources became toxic at elevated levels (7 mg N liter‐1). Methionine was not used as N source. Cells could not be completely depleted of P, but concentrations ≤ 0.01 mg P liter‐1 resulted in poor growth. Vitamin B12, but not thiamine or biotin, was required. Highest cell yields were at a PII‐metals concentration of 30 ml liter‐1; a t 100‐ml liter‐1 cell yield was very low. Additions (per liter) of Fe (0.5 mg) and Mo (0.1 mg) to the basal medium produced higher cell yields, but Cu (0.1 mg) and V (0.1 mg) inhibited growth.
Schizogony in Haemoproteus columbae Kruse*
Authors: AHMED FARID E. , MOHAMMED ABDEL‐HAFEZ H.
Published: May 2007

SYNOPSIS To fill in some of the gaps in our knowledge of Schizogony of Haemoproteus columbae Kruse, transmission experiments involving inoculation into pigeons (Columba livia Gmelin) of sporozoites from salivary glands of the hippoboscid fly Pseudolynchia canariensis (Macquart) were carried out. We were unable to detect prepatent schizonts or to observe schizogonic development when infection became chronic. Schizonts were mainly confined to lung tissue. Observations of parapatent schizonts were made in smears and tissue sections. A variety of forms was found. Cytomeres were rarely encountered. Two types of morphologically distinct merozoites were seen. One type was twice as large as the other and was thought to repeat the process of schizogony several times before invading erythrocytes. Schizonts with cytoplasmic clefts were not common in our material due to the fixatives used (Bouin's and Carnoy's). Merozoites were occasionally observed inside monocytes, probably being phagocytosed.
Cultivation of Leishmania donovani and Leishmania braziliensis in Defined Media: Nutritional Requirements
Authors: STEIGER ROLF F. , STEIGER ERICA
Published: May 2007

SYNOPSIS Nutritional requirements of promastigotes of Leishmania donovani and Leishmania braziliensis were studied in modifications of a simple defined culture medium. “Continuous growth,” considered as propagation through 10 successive passages, was supported by inorganic salts, 14 l‐amino acids (arginine, cysteine, glutamine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, threonine, tryptophan, tyrosine, valine), glucose, adenosine, and a mixture of 11 vitamins and related growth factors. Purified defatted bovine serum albumin proved beneficial. The nutritional needs of the above species of Leishmania differ from those of 2 other hemoflagellate species, Leishmania tarentolae and Crithidia fasciculata, for which glucose, proline and glutamine were found to be nonessential. It is suggested that lower hemoflagellates may be capable of synthesizing these substrates de novo. Leishmania donovani and L. braziliensis required higher levels of folic acid than L. tarentolae, probably due to the fact that folates are involved as cofactors in the biosyntheses of pyrimidines and serine. Although the mixtures reported here cannot be regarded as “minimal essential” media, they are considerably less complex than the ones employed so far for cultivating hemoflagellates, and are therefore well suited for studies related to nutrition and biosynthetic capabilities of Trypanosomatids.
Gradionation: Hypothesis for Positioning and Patterning*
Authors: ROTH L. E. , PIHLAJA D. J.
Published: May 2007

SYNOPSIS. The interaction of contiguous proteins is explored in microtubules, rosettes, and membranes based on the well established molecular phenomena of cooperativity and allosterism. It is proposed that conformational gradients in protein arrays cause the formation of gradions by nearest‐neighbor interactions. Gradions are repeating functional molecular sequences that contain several conformational forms of one or more proteins, with the result that different reactive sites can exist in the same molecular architecture at any one time. Gradionators are small controlling molecules that may be microscopically visible as layers or linkages, but could also be smaller. Some of the presently available supporting evidence and its functional implications are discussed, including the possibility that the raison d'etre for membrane‐particle arrays is to enhance the regulation and amplification capabilities of cell systems.
Molecules and Morphologies: The Perpetuation of Pattern in the Ciliated Protozoa*†
Authors: NANNEY D. L.
Published: May 2007

SYNOPSIS. Three apparently conflicting generalizations concerning the relationships between molecules and cell structure may be derived from studies on cellular patterning in the ciliates. (A) Cells with identical genes and molecular composition may have different hereditary patterns. (B) Genes, through their prescribed molecular derivatives, constrain the modes of pattern permutation and define the states of greatest stability. (C) Cells with identical hereditary patterns may have entirely different genes and molecular compositions. These principles may be reconciled through the recognition that they are characteristically applicable over different time intervals. Hereditary differences within a clone and without related molecular differences (principle A) may persist for hundreds of cell generations, but they are resolved eventually within a constant environment (principle B) as the configuration of minimal free energy is approached. On an even longer time scale, molecular substitutions have occurred for many or most components of the cell, but these have been constrained by selective pressures on an ancient design (principle C) that disallow substitutions affecting certain form‐function relations which have been elevated to an adaptive peak.
Revision and Checklist of the Species (Other Than Lecudina) of the Aseptate Gregarine Family Lecudinidae*
Authors: LEVINE NORMAN D.
Published: May 2007

SYNOPSIS. A checklist is given of the 89 named species of the gregarine family Lecudininae, exclusive of the 42 named species of the genus Lecudina (phylum Apicomplexa. class Sporozoea, subclass Gregarinia, order Eugregarinida, suborder Aseptatina). The list includes also the synonyms, host names, locations in hosts, known geographic distributions of the species, as well as key references. Another list is given of synonyms, lapsi calami, nomina nuda, etc., associated with the genera. A new genus, Paraophioidina g. n., with type species, Paraophioidina haeckeli (Mingazzini, 1891) and a new species, Lankesteria ormieresi sp. n., are described. There are also new combinations in the genera Bhatiella, Ancora, Monocystella, Ascocystis, and Paraophioidina.
Scanning Electron Microscopy of Budding and Metamorphosis in Discophrya collini (Root)*
Authors: HENK WILLIAM G. , PAULIN JEROME J.
Published: May 2007

SYNOPSIS. Budding and metamorphosis in the suctorian ciliate, Discophrya collini, have been investigated by scanning electron microscopy. The adult body form, tentacles, stalk, and attachment disk are described. A field of depressions or small pits was observed in the pellicle of adult suctorians in the early stages of bud formation. These pits deepen and coalesce until one large pore, the birth pore, remains. Cilia protrude through the pore, and as eversion of the bud proceeds the meridional arrangement of the larval ciliation is evident. After eversion is completed, a pronounced division furrow is found between the adult and soon‐to‐be‐released swarmer. The stalk‐forming region is seen on swarmers. Metamorphosing swarmers produce tentacles upon settling before any indication of ciliary resorption. Resorption of cilia and change in body form occur progressively with the production of the attachment disk and stalk.
Coccidian Parasites of Intertidal Fishes from Wales: Systematics, Development, and Cytochemistry
Authors: DAVIES ANGELA J.
Published: May 2007

SYNOPSIS. Examination of littoral fish Blennius pholis and Cottus bubalis caught at Aberystwyth and Porth Cwyfan, Wales. U.K., revealed 2 species of coccidia.

Eimeria dingleyi sp. n. Oocysts spherical (16.1–19.2) to subspherical (13.9–14.2 × 18.8–20.0) μm, with thin walls; sporulation outside the host to produce ellipsoid sporocysts; endogenous phases in epithelial cells throughout intestine; 26 of 58 B. pholis infected.

Eimeria variabilis (Thélohan) Reichenow. Oocysts spherical (11.9–14.6) to subspherical (9.2–10.9 × 13.9–14.3) μm; sporulation in lining of pyloric ceca and rectum; previously unrecorded schizonts and gametocytes present; 21 of 25 C. bubalis infected.

Electron microscopy revealed that the oocyst wall of E. variabilis consists of a thin membrane whereas the sporocyst wall is thick and 3‐layered. Typical oocyst wall‐forming bodies were absent from the macrogamete. Cytochemical tests on the endogenous stages of E. dingleyi and E. variabilis indicated that in general they resembled other coccidia in their chemical constitution.