bluuebunny/crossref_metadata_2025 huggingface dataset:
Etude Cytoloique des Premiers Stades du Developpement d'une Coccidie: Myriosporides amphiglenae
Authors: HENNERÉ E.
Published: May 2007

SYNOPSIS. We have undertaken the study of intracellular parasites which probably constitute one of the stadia of the development of a coccidium: Myriosporides amphiglenae. This study, carried out by means of optical microscopy as well as electron microscopy, has allowed the observation of close similarities with Plasmodium, Lankesterella, Eimeria, Toxoplasma and Sarcocystis. The wall consists of 3 membranes and has a micropore. Besides classical cytoplasmic inclusions (mitochondria, Golgi system, ergastoplasm and vacuoles), various tubular forms fill the anterior third of the cell, in which about twenty hollow peripheral fibrils are also observed.
Schizogony and Gametogony of Leucocytozoon simondi and Associated Reactions in the Avian Host*
Authors: DESSER SHERWIN S.
Published: May 2007

SYNOPSIS. Stages of development of Leucocytozoon simondi in White Pekin ducklings and their reactions to the parasite were studied on successive days after infecting them artificially with sporozoites from Simulium rugglesi. The minimum prepatent period was 5 days. The first asexual cycle occurred exclusively in the parenchymal cells of the liver. Progeny of these hepatic schizonts followed one of 3 courses: (a) invaded parenchymal liver cells to give rise to another hepatic cycle, (b) penetrated blood cells to form round gametocytes, and (c) were phagocytized by macrophages and grew into megaloschizonts thruout the body. The appearance of elongating gametocytes coincided with the period of maturation and release of merozoites from the megaloschizonts. Experimental evidence supports the hypothesis that the round gametocytes arise from the hepatic schizonts and the elongate forms from the megaloschizonts. Mature megaloschizonts released millions of merozoites, but a high 2nd peak in parasitemia did not develop because of retention of developing gametocytes in the deep circulation, particularly the liver and spleen, and a pronounced host reaction.
Induction of Trichocyst Discharge in Paramecium bursaria*
Authors: SCHUSTER FREDERICK L. , PRAZAK BESSEMARIE , EHRET CHARLES F.
Published: May 2007

SYNOPSIS. A method is described for obtaining trichocyst discharge in Paramecium using an extract of geranium leaves. The extract is easily prepared, gives readily reproducible results, and is only slightly toxic to the cells. Using this method, large quantities of trichocysts can be obtained for a variety of analyses.

Preliminary evidence suggests that the component of the extract active in causing trichocyst discharge is geranium tannic acid.
The Effect of a Eugregarine Gregarina polymorpha (Hammerschmidt) on the Mealworm Larva of Tenebrio molitor (L.)
Authors: HARRY OWEN G.
Published: May 2007

SYNOPSIS. The larva of the beetle Tenebrio molitor (Coleoptera, Tenebrionidae), commonly referred to as the mealworm, harbors considerable numbers of gregarines in its midgut. These are not necessary for normal growth, nor do they prolong the life of larvae grown under optimal conditions of temperature, relative humidity and diet. When the larvae were grown under optimal conditions there was no significant difference between the length of larval life or the final pupal weight of mealworms harboring gregarines when compared with mealworms which had been reared free from gregarines. This applied both to infected and non‐infected larvae grown singly and in communal cultures.

When, however, larvae were grown on a sub‐optimal diet, the gregarines had a considerable effect on the final pupal weight and the ability of the larva to complete development.
RNA Homologies Between Protozoa
Authors: GIBSON IAN
Published: May 2007

SYNOPSIS. Comparison of RNA molecules between certain protozoa using the technic of nucleic acid hybridisation revealed that there are complementary sequences for ribosomal RNA molecules in the genomes of such cells. Furthermore the genes for ribosomal RNA have been conserved during evolution in this group of organisms. On the other hand, RNA molecules from these protozoa which can be considered to be “messengers” show little in the way of sequence relationships. By utilising the technic of hybridisation it was found that Oxytricha can compete effectively against Paramecium ribosomal RNA for Tetrahymena DNA but the ribosomal RNA sequences of the latter could not compete completely against Paramecium ribosomal RNA for Oxytricha DNA. The result is interpreted to show that different ribosomal sequences were hybridising with each of the DNA samples from Tetrahymena and Oxytricha. A general interpretation of this result in terms of ribosome evolution is presented.
Trypanosoma lewisi Infections in Normal Rats and in Rats Treated with Dexamethasone
Authors: PATTON CURTIS L. , CLARK DAVID T.
Published: May 2007

SYNOPSIS. Administration of dexamethasone to rats infected with Trypanosoma lewisi resulted in the development of exceedingly large populations of trypanosomes which were fatal to their hosts. The elevated levels of parasitemia in treated rats early in infections were thought not to be a result of an increased reproductive rate. However, trypanosomes in treated rats 2 days postinfection did have a higher coefficient of variation in total length and a greater percentage of dividing forms than those observed from infected rats which were not given the drug. The course of infection may be markedly altered not only in intensity but also in length by this corticosteroid. It is suggested that dexamethasone administered at the levels recorded to rats infected with T. lewisi inhibits the production of ablastin and trypanocidal antibodies.
The Leishmania‐Leptomonad Transformation of Leishmania donovani: Nutritional Requirements, Respiration Changes and Antigenic Changes*
Authors: SIMPSON LARRY
Published: May 2007

SYNOPSIS. The leishmania‐leptomonad transformation of Leishmania donovani occurs in 20–40 hr in vitro at 27 C in the absence of cell division. The rate and extent of the process depend on the available nutrients. A source of amino adds and glucose (or sucrose) are required. Several basic or acidic amino acids can substitute for all amino acids present in the complete medium. Leishmanial forms freshly isolated from hamster spleen have a QO2 (μM O2/min/107 cells) of 0.29 ± 0.01 at 27 C in phosphate buffered saline with glucose. This respiration is sensitive to KCN, antimycin A, and Na amytal, and hence is probably cytochrome dependent. The QO2 remains constant for 5–6 hr and then increases 5–7 fold by 20–30 hr of incubation at 27 C in the proper medium. The transformation is inhibited in terms of morphogenesis and increase in respiration by Actinomycin D, puromycin and mitomycin C. Appearance of new soluble antigens during the transformation was found by gel diffusion and immunoelectrophoresis.
Biochemical and Ultrastructural Changes in Tetrahymena pyriformis During Starvation*
Authors: LEVY MICHAEL R. , ELLIOTT ALFRED M.
Published: May 2007

SYNOPSIS. Certain of the ultrastructural and biochemical changes occurring during the first 25 hr of starvation in Tetrahymena pyriformis were studied. Ultrastructurally, numerous profiles of degenerating mitochondria were seen in the early stages of starvation. The presence of oxidizable substrate such as glucose and acetate did not prevent this degeneration. Numerous large nucleoli were formed, many of which seemed to be passing into the cytoplasm as forming autophagic vacuoles. There was a transient increase in Oil Red O‐positive bodies, presumably lipid (triglycerides). The extent and duration of this increase were pronounced in the presence of acetate. The lipid droplets appeared to arise within the cisternae of the endoplasmic reticulum. Lipid reserves were apparently utilized prior to carbohydrates, as the disappearance of lipid droplets preceded glycogen utilization, both in the presence of acetate and in the absence of exogenous substrate. A considerable loss of cellular protein also occurred. In cells from inorganic medium supplemented with glucose, glycogen occupied much of the cell, leaving only islands of cell organelles. Acid phosphatase was localized, ultrastructurally, mainly in autophagic vacuoles which contained mitochondria and other cell organelles, and in association with small, double‐membraned structures which seemed to be sequestering small areas of cytoplasm. Such sequestered areas also appeared within larger autophagic vacuoles. Residual bodies containing concentric whorls of myelin‐like membranes surrounding a more solid core accumulated during starvation. Acid phosphatase activity decreased in amount but not in specific activity. The specific activity of cathespin doubled or tripled, but there was little change in total enzyme.
The Preservation of Tintinnids1
Authors: GOLD KENNETH
Published: May 2007

SYNOPSIS. The use of a preservative for delicate marine protozoa is described.
Carbohydrate Transport in Trypanosoma gambiense*
Authors: SOUTHWORTH G. CLARK , READ CLARK P.
Published: May 2007

SYNOPSIS. The uptake of 14C‐labeled carbohydrates by Trypanosoma gambiense was studied. Glucose, mannose, glycerol, 2‐deoxyglucose and fructose were rapidly absorbed by the parasite, and all had saturation kinetics. The glucose analog 3‐O‐methylglucose was not taken up by T. gambiense.

Competitive inhibition experiments indicate that there are 2 transport loci for the tested substrates. It is suggested that there is a “glucose site” thru which glucose, mannose and glycerol, but not fructose, are transported and a “fructose site” thru which only fructose is transported. The specificity of the glucose‐transporting mechanism appears to differ from those of other animals.
The Cytostome of Trypanosoma cruzi and T. conorhini*
Authors: MILDER REGINA , DEANE MARIA P.
Published: May 2007

SYNOPSIS. A cytostome is described in culture forms and in intracellular stages of Trypanosoma cruzi and in culture forms of T. conorhini. The organelle opens into the flagellar pocket or close to it and runs deeply into the cell.
Specificity of Sugar Transport in Trypanosoma gambiense*
Authors: SOUTHWORTH G. CLARK , READ CLARK P.
Published: May 2007

SYNOPSIS Some carbohydrates inhibited glucose and fructose transport in Trypanosoma gambiense. Glucose transport was inhibited by glycerol, mannose, 2‐deoxy‐D‐glucose, glucosamine and N‐acetylglucosamine. Fructose transport was inhibited by glucose, glycerol, mannose, glucosamine and N‐acetylglucosamine. Glucosamine transport appeared to be a mediated process and had a Km of 1.20 mM and a Vmax of 28.5 μM glucosamine/g dry wt/2 min. Glucosamine absorption was competitively inhibited by glucose, fructose and N‐acetylglycosamine. N‐Acetylglucosamine appeared to enter by passive diffusion. Reciprocal inhibition experiments suggested that glucosamine entered entirely via the “fructose site.” Specificity of sugar transport in T. gambiense differs from that of other organisms.
Growth and Toxigenesis of the Chrysomonad Prymnesium parvum as a Function of Salinity*
Authors: PADILLA GEORGE M.
Published: May 2007

SYNOPSIS The euryhaline chrysomonad Prymnesium parvum (Carter) was grown in artificial (ASW) and natural sea water (NSW) media at salinities 1.3‐33.3 ‰, and constant illumination. Low salinities (< 10‰) increased the doubling time (DT) and induced higher levels of protein and nucleic acids. DT was lowest for cells in ASW at 25 ‰ and NSW 17.9 ‰. The protein content was more variable. RNA content was lowest for cells at ca. 10 ‰. The DNA content was lowest for cells in 10‰ ASW and 11‰ NSW. Generally, the cells grew faster in NSW but had less protein and RNA than cells in ASW. The highest hemolytic content was in cells grown at 22.8 ‰ ASW or NSW. Glycerol enhanced growth rate and toxin synthesis within 24 hr of addition to the cells. Hemolysis was inhibited by high pH's. A membrane fraction containing ca. 20% of the hemolysin was isolated by density gradient centrifugation.
Further Studies on the Effects of Antipantothenates on Malaria Parasites (Plasmodium coatneyi and P. falciparum) in vitro*
Authors: TRAGER WILLIAM
Published: May 2007

SYNOPSIS. Plasmodium coatneyi and P. falciparum were maintained in host erythrocyte suspensions in vitro under conditions supporting one cycle of development with reinvasion occurring after 2 days. Inhibitory effects were then assessed for a series of analogs of pantothenic acid. In compounds of the general formula R‐sulfamoylethyl‐2,4‐dihydroxy‐3,3'‐dimethyl butyramide antimalarial activity was strongly influenced by the nature of the R group. Most active was the compound with R = methoxy‐quinolyl; this material had an in vitro activity approaching that of primaquine. If R was chloro‐ or dichlorophenyl, activity was much greater than if it was fluoro‐ or difluorophenyl. Small changes at the other end of the molecule had less effect; addition of a methyl group to give the valeramide, or omission of the 2‐hydroxy did not change activity. Sulfonylethyl and thio‐ethyl compounds were less active than the sulfamoylethyl compounds.
Glucose Utilization by Euglena gracilis var. bacillaris at Higher pH*
Authors: HURLBERT RONALD E. , BATES ROBERT C.
Published: May 2007

SYNOPSIS. Euglena gracilis var. bacillaris is able to grow luxuriantly on glucose in a mineral salts medium at pH 6.8–7.1 following an adaptation period of about 200 hr. If adapted cells are used as an inoculum or if 0.1% glycine is included in the medium, the lag is shortened to 70–100 hr. Inclusion of 0.1% acetate in the medium produces a diphasic growth pattern, with acetate being metabolized first, followed by the later (about 400 hr) utilization of the glucose. Glucose utilization was found to be sensitive to pH as compared to growth on ethyl alcohol. However, glycine partially overcame this sensitivity. Glycine is maximally stimulatory with regard to growth on glucose at pH 7.0 at a concentration of 0.03%, thus suggesting that it functions as a sparking substance. Glycine markedly stimulates the assimilation of 14C‐glucose. A number of Krebs cycle acids and amino acids were also found to stimulate 14C‐glucose assimilation at neutral pH.

Adaptation to glucose utilization at neutral pH was due to the appearance of mutants able to grow more rapidly under these conditions. The nature of this mutation was not determined.
Kinetics of Incorporation of DNA Precursors from Ingested Bacteria into Macronuclear DNA of Paramecium aurelia12
Authors: BERGER JAMES D.
Published: May 2007

SYNOPSIS. The kinetics of transfer of tritium‐labeled material from the DNA of ingested bacteria into macronuclear DNA of Paramecium was examined by autoradiography. Bacteria labeled with tritiated thymidine were almost immediately incorporated into food vacuoles, thus becoming available for digestion and a potential source of labeled DNA precursors. Soluble label derived from food vacuoles appeared in low concentrations in the cytoplasm soon after cells were transferred to medium with labeled bacteria; incorporation of labeled precursors into macronuclear DNA began within 5 min.

Labeled food vacuoles remained as potential sources of tritiated DNA precursors for a long and variable period after removal of labeled cells to non‐labeled medium. The activity of the soluble cytoplasmic DNA precursors decreased parallel to the loss of labeled food vacuoles and no soluble DNA precursors were carried over from one macronuclear DNA synthetic period to the next.

Labeling experiments were designed, using this information, which allowed determination of the pattern of macronuclear DNA synthesis and nuclear mass increase during the cell cycle. Macronuclear DNA synthesis began 25–30% of the way thru the cell cycle, continued at a constant rate during the middle half, and decreased in rate during the last quarter. Macronuclear mass increased in an approximately linear fashion, beginning with the onset of DNA synthesis and doubling by the time of karyokinesis.
Effects of Different Substrates on Glucose Uptake and Hexokinase Activity in Euglena gracilis*
Authors: GRAVES LYNN B.
Published: May 2007

SYNOPSIS. Hexokinase levels and glucose uptake rates were measured in cells of Euglena gracilis adapted for growth on glucose, acetate, and ethanol. Glucose‐grown cells had 3 times the hexokinase levels found in acetate‐ and ethanol‐grown cells. However, glucose‐ and ethanol‐grown cells had the same rates of glucose uptake, while acetate‐grown cells accumulated only 1/8 as much glucose in the same interval.
Cultivation and Morphogenesis of Trypanosoma cruzi in Improved Liquid Media1
Authors: PAN CHIA‐TUNG
Published: May 2007

SYNOPSIS. Two liquid media (F‐29 and F‐32) have been developed for the serial cultivation of T. cruzi amastigotes. F‐29 consists of synthetic tissue culture fluid 199, trypticase, hemin and bovine fetal serum; F‐32 is F‐29 plus chicken plasma.

The inocula for serial cultivation in both media contained over 99% epimastigotes. The proportion of structural types in the original inocula did not change significantly during 10 serial passages in F‐29 medium at 29.5 C. However, in the 2nd passage in F‐29 medium at 35.5 C most of the organisms becme amastigotes, and after several more subcultures over 92% were amastigotes.

During the original passage in F‐32 medium at 35.5 C. over 90% of the organisms were trypomastigotes with terminal kinetoplasts. After several more passages, and regardless of incubation temperature (29.5–35.5C), over 94% became amastigotes.

In either F‐29 or F‐32 a 7‐fold increase of amastigotes may be obtained after 4‐day incubation at 35.5 C.
Plasmodium berghei NK65 in the Inbred A/J Mouse: Variations in Virulence of P. berghei Demes*
Authors: ALGER NELDA E. , BRANTON MARILYN , HARANT JOYCE , SILVERMAN PAUL H.
Published: May 2007

SYNOPSIS. Plasmodium berghei NK65 was passed thru Anopheles stephensi to golden hamsters and mice. The percent cumulative mortality was compared after each mosquito passage in early (7–13) blood passages. The strain was found to have divided into demes (populations) retaining original virulence and demes which were less virulent. The separation of virulent and less virulent demes was traced to its origin. Both virulent and less virulent demes can be passed thru mosquitoes and hamsters. No concomitant organism has been identified.
Etude Comparée de Quelques Grégarines Acanthosporinae
Authors: BAUDOIN JACQUES
Published: May 2007

SYNOPSIS. Numerous species of gregarines of subfamily Acanthosporinae are parasites of Trichoptera and Coleoptera. Eight species belonging to genus Ancyrophora are compared. One of them, A. rostrata, is new. This study makes it possible to recognize also a new genus, named Rhizionella and erected to contain another new species, R. tenuis.
Melatonin: Inhibition of Microtubule‐Based Oral Morphogenesis in Stentor coeruleus
Authors: BANERJEE S. , KERR V. , WINSTON M. , KELLEHER J. K. , MARGULIS L.
Published: May 2007

SYNOPSIS. The temporal separation of macromolecular syntheses from protein assembly into microtubular structures has permitted the use of the Stentor ciliated oral membranellar band regenerating system as an assay for mitotic spindle inhibitors (Banerjee & Margulis, 1971). Melatonin, the pineal gland hormone, is additive to Colcemid in this assay; like Colcemid it specifically inhibits band migration as a sensitive function of developmental stage and concentration. Altho the entire process of band formation and cilia regeneration (stages 0–8) is inhibited by melatonin, stage 3 is especially sensitive.

Delay in morphogenesis at stage 3 can be measured as a precise function of inhibitors (Colcemid, podophyllotoxin, melatonin) of the form y=kxn, where y is delay in hours and k is the concentration of inhibitor in moles. Riboflavin (0.2 μM) and nicotinamide (0.2 μM) in combination reversed Colcemid‐induced delay in band regeneration, but (unlike melatonin) the vitamins alone were totally without effect on the regenerating system. Therefore melatonin probably interacts with microtubule protein whereas the B vitamins interact in some way with Colcemid to nullify its activity.
In vitro Maintenance of the Trophonts and Sporozoites of Pyxinia crystalligera*
Authors: COLLINS RICHARD L.
Published: May 2007

SYNOPSIS. In a study of in vitro maintenance of the trophonts and sporozoites of the cephaline gregarine, Pyxinia crystalligera, a basal medium consisting of salts, reducing agents, and antibiotics was supplemented by fetal bovine serum, serum protein fraction IV‐4, or protein hydrolysates. Motility was used as the viability criterion. The tests were terminated when viability was ∼30% of the original inoculum.

Two‐week survival of trophonts was observed with 0.75% protein fraction, 80% of organisms remaining viable at the end of 1 week. Similar results were noted with 2% casein hydrolysate. With lactalbumin hydrolysate and Casamino acids trophonts remained viable for 6 days, and with fetal bovine serum the results were similar to those obtained with lower concentrations of protein fraction IV‐4.

Sporozoites remained motile for up to 5 days in the basal medium supplemented by both protein fraction IV‐4 and diluted haemocoelic contents of the host, Dermestes vulpinus, but only for 3 days or less in that supplemented by the protein fraction alone.

The characteristic crystals of trophonts were dissolved or possibly utilized during in vitro maintenance. A new type of crystal, however, was observed in forms kept in the presence of higher protein hydrolysate concentrations. Smaller trophonts were more adaptable to maintenance than larger ones, for rapid depletion of paraglycogen and resorption of the deutomerite often was observed in the latter.

Results of cytochemical tests for carbohydrates, neutral lipids, and proteins indicated that the trophonts were capable of paraglycogen synthesis in vitro.
The Effect of Diphenylamine on Terminal Respiration in Bloodstream and Culture Forms of Trypanosoma brucei*
Authors: EVANS D. A. , BROWN R. C.
Published: May 2007

SYNOPSIS. Diphenylamine was shown to be a potent inhibitor of cyanide insensitive respiration in both bloodstream and newly established culture forms of the same isolate of Trypanosoma brucei, with the L‐α‐glycerophosphate oxidase system having the greatest sensitivity to the inhibitor. The NADH oxidase activity of bloodstream forms was at least twice as sensitive to diphenylamine as the corresponding activity in culture forms, suggesting different routes of NADH oxidation in the 2 forms. The oxidation of L‐α‐glycerophosphate was inhibited to a similar degree in both culture and bloodstream forms. L‐α‐glycerophosphate oxidation in bloodstream forms differed from that found in culture forms in that the bloodstream system, unlike that in the culture form, was unable to donate electrons to cytochrome c. In culture form trypanosomes there was a distinct difference in the degree of diphenylamine inhibition on the oxidation of L‐α‐glycerophosphate, NADH, and succinate, suggesting the participation of separate flavoproteins in the oxidation of these substrates.
Differential Effect of Phosphate Starvation on the Rates of Cell Division and Plastid Replication in Euglena*
Authors: PARENTI FRANCESCO , DIPIERRO SILVIO , PERRONE CESIRA
Published: May 2007

SYNOPSIS. The effects of phosphate starvation on the synthetic and division rates of Euglena gracilis strain Z are described. Phosphate starvation inhibits rates of the following processes, in the order: RNA synthesis > DNA synthesis > cell division > chlorophyll synthesis and plastid replication. As a consequence of the differential effect of phosphate starvation on the synthetic and division rates the average gross chemical composition of the cells is subject to continuous change.
A Check‐List of the Species of the Genus Leucocytozoon (Apicomplexa, Plasmodiidae)*
Authors: HSU CHAO‐KUANG , CAMPBELL G. ROBERT , LEVINE NORMAN D.
Published: May 2007

SYNOPSIS. A list is given of 67 named species of Leucocytozoon considered valid at present. Another list is given of 1 reptilian and 146 avian hosts of named species of Leucocytozoon. A 3rd list is given of 34 synonyms. Leucocytozoon has been named from about 0.7% of the approximately 8600 species of birds that exist. The following new taxonomic names are included: L. danilewskyi var. hirundinis Sergent & Sergent, 1905 is emended to L. hirundinis; Saurocytozoon tupinambi Lainson & Shaw, 1969 is changed to Leucocytozoon (Saurocytozoon) tupinambi (Lainson & Shaw, 1969).
The Fate of RNA Degradation Products in Starved Cultures of Tetrahymena pyriformis W.*
Authors: KOROLY MARY J. , CONNER ROBERT L.
Published: May 2007

SYNOPSIS

The RNA content of a population of Tetrahymena pyriformis W was followed during the growth phases of the culture. The cellular RNA levels were found to reach a maximum in early log phase and to decrease throughout the remainder of the log and deceleration phases. There was a 25% decrease in RNA amount when cells in late stationary phase were compared to those in deceleration. This loss of RNA was mimicked when cells from the deceleration phase were suspended in a non‐nutrient buffered medium.

Procedures were established to determine RNA content and the intra‐ and extracellular distribution of RNA degradation products, namely purine and pyrimidine bases and orthophosphate. Balance sheets are presented to show that the decrease in RNA levels was accompanied by an equivalent increase in purine and pyrimidine bases and phosphorus derivatives. The validity of the procedures employed was demonstrated. The influence of magnesium, cholesterol and glucose on the cells suspended in a non‐nutrient buffer was examined. Each was found to affect the ultimate distribution of RNA products in a characteristic fashion suggesting that each compound acts by a different mode of action.
Life Cycle of Isospora canis Nemeséri, 1959 in the Dog*
Authors: LEPP DONALD L. , TODD KENNETH S.
Published: May 2007

SYNOPSIS

The life cycle of I. canis Nemeséri, 1959 was studied in experimentally infected dogs. Freshly sporulated oocysts were ovoid and 34–40 × 28–32 μm. The endogenous stages were found directly beneath the epithelium of the distal portion of the small intestinal villi. Most of the endogenous stages were in the lower 1/3 of the small intestine, but occasionally they were found in other portions of the small intestine. Three asexual generations were present. First‐generation schizonts were 16–38 × 11–23 μm and contained 4–24 merozoites; mature 1st‐generation merozoites were 8–11 × 3–5 μm. First‐generation schizogony lasted up to 7 days after inoculation. Second‐generation schizonts were 12–18 × 8–13 μm and contained up to 12 merozoites which were 11–13 × 3–5 μm. Second‐generation schizogony was present on postinoculation days 6 and 7. Third‐generation schizonts were formed by nuclear division of 2nd‐generation merozoites. Most 2nd‐generation merozoites underwent nuclear division without leaving the parasitophorous vacuole of the 2nd‐generation schizont. Mature 3rd‐generation schizonts were 13–38 × 8–24 μm and contained 6–72 merozoites. Third‐generation merozoites were 8–13 × 1–3 μm. Third‐generation schizogony was present on days 6–8 after inoculation. Mature macrogametes were 22–29 × 14–23 μm. Mature microgametocytes were 20–38 × 14–26 μm. Gametes were present on postinoculation days 7–10. Oocysts were present in tissue sections on postinoculation days 8–10 and 12. The prepatent period was 9–11 days.
Ultrastructural Changes During Encystment of Schizopyrenus russelli*
Authors: MAITRA S. C. , SAGAR P. , AGARWALA S. C.
Published: May 2007

SYNOPSIS

Ultrastructural changes associated with the encystment of Schizopyrenus russelli have been studied by electron microscopy. Before encystment small “black bodies” appear in the cytoplasm and later migrate toward the periphery. The outer cyst wall is secreted at this stage as a thin discontinuous layer which thickens and subsequently becomes continuous. Concomitant with this, the endoplasmic reticulum surrounds the mitochondria. The inner cyst wall later appears as a multilayered structure which presumably is cast off from the plasma membrane. Between the inner and outer layers of the cyst wall, there is a middle, less electron‐dense layer wherein extruded cytoplasmic material is found embedded at certain places.
Cytologic and Autoradiographic Studies of the Micronucleus at Meiotic Prophase in Tetrahymena pyriformis
Authors: SUGAI TOSHIRO , HIWATASHI KOICHI
Published: May 2007

SYNOPSIS

Micronuclear changes of variety 1 of Tetrahymena pyriformis during meiotic prophase have been observed by the light microscope. Morphologic changes in the micronucleus are divided into 6 stages. In stage I, chromatin begins to polarize; in stage II, the micronucleus becomes spindle shaped; and in stage III, one end of the micronucleus protrudes to form a “neck.” In stage IV, where the micronucleus elongates to maximal length, the whole micronucleus consists of 2 chromatin threads pairing longitudinally. One thread probably contains one genome. In stage V, the elongated thread becomes shorter and thicker. Finally, in stage VI, separate chromosomes appear and enter into metaphase.

To discover the role of the elongation of the micronucleus, called crescent formation, autoradiographic analysis of RNA and DNA synthesis were undertaken using [3H]uridine and [3H]thymidine. Pulse label and chase experiments show that the crescent in stages II and III is actively synthesizing RNA. Though no remarkable DNA synthesis was observed during meiosis, a small amount of DNA synthesis occurred during the 1st and 2nd prezygotic divisions.
Agglutination of Trypanosoma cruzi by Concanavalin A*
Authors: ALVES M. J. M. , COLLI W.
Published: May 2007

SYNOPSIS

Epimastigotes of Trypanosoma cruzi obtained in culture agglutinate readily with low concentrations of concanavalin A (Con A). Agglutination was linear with time up to 10 min providing that the initial cell density was greater than 1 × 108 cells/ml. Under these conditions, the percentage agglutination was dependent on the Con A concentration. Agglutination was inhibited by α‐methyl D‐mannoside, α‐D‐mannose, and α‐D‐glucose. Pretreatment of cells with trypsin had no effect on the epimastigote agglutinations.

Blood forms (trypomastigotes) of T. cruzi did not agglutinate even in the presence of 100 times more Con A. Results suggest differences in membrane structure between blood forms and cultured epimastigotes of T. cruzi. These membrane differences might be related to the different pathogenic properties of both cell forms of T. cruzi.
Mating Reaction and its Daily Rhythm in Euplotes crassus*†
Authors: MIYAKE AKIO , NOBILI RENZO
Published: May 2007

SYNOPSIS

The agglutinative mating reaction of Euplotes crassus occurred without lag if complementary mating types were brought together under appropriate conditions. Only a small fraction of the cell population reacted at the beginning but the number of reacting cells steadily increased until firmly united pairs were formed after ∼30 min. The intensity of the initial mating reaction changed rhythmically; the rhythm appeared circadian. Mating‐type‐specific soluble factors did not appear to participate in this reaction. The results strongly support the positive‐feedback hypothesis of the mating reaction presented by Heckmann & Siegel in 1964. Patterns of preconjugant cell interactions of different ciliates are discussed.
Selective Effects of Enucleation and Transfer of Heterologous Nuclei on Cytoplasmic Organelles in Amoeba proteus*
Authors: JEON KWANG W.
Published: May 2007

SYNOPSIS. The ultrastructural changes in the cytoplasm of lethal hybrids obtained by nuclear transplantation between different strains of Amoeba proteus were compared with those of enucleated amebae. It was found that, whereas the Golgi complex and glycocalyx degenerated first in enucleated cells, mitochondria and endosymbiotes became abnormal first in the hybrids. The selective effects are attributed to the presence of nucleic acids in the mitochondria and endosymbiotes and hence to the different interactions they would have with the nuclear genome.
Rumen Ciliates of the Tsessebe (Damaliscus lunatus lunatus) in South Africa*
Authors: VAN HOVEN W.
Published: May 2007

SYNOPSIS. Ciliate protozoa from the rumen of the tsessebe, Damaliscus lunatus lunatus, all belong to the family Ophryoscolescidae and no holotrichs were found in any of the 16 animals. Eighteen species were identified of which Entodinium fyferi sp. n., Enoploplastron garstangi sp. n. and Epidinium lunatus sp. n. are new and have been described for the first time. A short redescription of Eremoplastron gigantium Kofoid & MacLennan is given.
Influence de la Concentration Bacterienne sur la Croissance de Colpidium campylum*
Authors: DIVE DANIEL
Published: May 2007

RÉSUMÉ. L'étude de la phase de latence et du début de la phase exponentielle de croissance dans des cultures monoxéniques de Colpidium campylum a été réalisée en examinant l'influence de la concentration en bactéries à la fois sur le nombre d'individus, leur volume moyen et le biovolume total de la population de Ciliés. Il est possible de définir plusieurs phénomènes liés à l'abondance du substrat, en particulier une concentration critique conditionnant la maintenance de la population et une diminution du taux d'assimilation consécutive à une suralimentation.

A partir des résultants obtenus, la notion de volume minimum nécessaire à la division et l'interaction entre l'énergie nécessaire à la synthèse de matière vivante et celle liée à la nutrition, sont discutées afin d'expliquer l'évolution des cultures.

SYNOPSIS. In a study of the stationary and the early exponential growth phases of the monoxenic cultures of Colpidium campylum, the influence of the bacterial concentration upon the number of ciliates, their mean volume, and the biomass of the total ciliate population was examined. It is possible to identify several phenomena linked to the abundance of the substrate, particularly a critical concentration affecting the maintenance of the ciliate population, and a decrease of the assimilation rate following overfeeding.

On the basis of the results obtained, an estimate of the minimum volume necessary for division as well as the interaction between the energy required for the synthesis of living matter and that derived from nutrition are discussed, to explain the development of the cultures.
Studies on the Conditions Required for Optimum Recovery of Tetrahymena pyriformis Strain S (Phenoset A) after Freezing to and Thawing from –196 C
Authors: OSBORNE JACQUELINE A. , LEE DONALD
Published: May 2007

SYNOPSIS

The toxicity of several cryoprotective agents was tested at room temperature (23 C) against Tetrahymena pyriformis strain S (Phenoset A) at different stages of the growth cycle. Polyvinylpyrrolidone (PVP‐40) at 10% (v/v) concentration was without effect at any stage in the growth cycle, while 1.2 M glycerol immobilized the cells which were disrupted very shortly afterwards. The toxicity of 0.25 M glucose was largely independent of the position of the cells in the growth cycle, but the toxicity of 0.25 M sucrose and 1.4 M dimethylsulfoxide (DMSO) was most marked in late log‐ and stationary‐phase cells. After log‐phase cells had been equilibrated with 1.4 M DMSO for 1 hr, the number of cells surviving cooling at defined rates from 0.45 to 12 C/min decreased as the final temperature decreased from –30 to –60 C.

A temperature of –53 C was found to be the optimum from which cells cooled at a given rate could be cooled rapidly to –196 C. Nevertheless, when cells were cooled at defined rates to –35, –45, or –53 C and then rapidly to –196 C the optimum rate of cooling to these temperatures was found to be 1 C/min. The optimum rate of cooling to –60 C prior to plunging into liquid nitrogen was found to be 2.7 C/min.
A Branched‐chain Amino Acid Aminotransferase from the Rumen Ciliate Genus Entodinium
Authors: WAKITA MASAAKI , HOSHINO SADAO
Published: May 2007

SYNOPSIS

A branched‐chain amino acid aminotransferase was extracted from rumen ciliates of the genus Entodinium and was partially purified by Sephadex G‐200, DEAE‐cellulose and DEAE‐Sephadex A‐50 column chromatography. The purified enzyme was active only with leucine, isoleucine and valine, and required pyridoxal phosphate as cofactor. The amino acids competed with each other as substrates. The enzyme had optimal activity at pH 6.0 in phosphate buffer. The Km values for the substrates and cofactor are as follows: 1.66 for leucine; 0.90 for isoleucine; 0.79 for valine; 0.29 mM for α‐ketoglutarate: and 0.1 μM for pyridoxal phosphate. Enzyme activity was inhibited by p‐chloromercuribenzoate and HgCl2. Gel filtration indicated the enzyme to have a molecular weight of 34,000.
Mucocysts in the Heterotrich Ciliate Spirostomum*
Authors: WINET H. , JONES A. R.
Published: May 2007

SYNOPSIS

Mucus‐like secretions by Spirostomum are demonstrated by a combination of anatomic and hydrodynamic technics whereby the presence of mucocysts and trails formed by their secretions can be shown. The mucocysts in this heterotrich differ somewhat in form and content from those reported for hymenostomes. It is suggested that the mucuslike secretions aid in lubrication when the ciliate swims near a solid boundary and reduce unsteady hydrodynamic effects when the organism swims in unobstructed fluid.
Toxoplasma ranae sp. n. from the Leopard Frog Rana pipiens Linnaeus*
Authors: LEVINE NORMAN D. , NYE RICHARD R.
Published: May 2007

SYNOPSIS. Toxoplasma ranae sp. n. is described from the brain of a leopard frog, Rana pipiens, probably from Mexico. Its pseudocysts were 72(55‐106) × 48(29‐70) μm in fixed sections. They contained an average of ∼ 4,000 slightly curved elongate zoites measuring 4–5 × 0.5 μm, with a central, spherical, vesicular nucleus.
Fine Structure of Sarcocystis cruzi Schizonts
Authors: PACHECO NANCY D. , FAYER RONALD
Published: May 2007

SYNOPSIS Schizogony of Sarcocystis cruzi Hasselmann (syn. S. fusiformis Railliet) takes place in vascular endothelial cells 26 to 33 days after cattle ingest sporocysts from dogs. Kidney cortex from a heavily infected, dexamethasone‐treated bovine was fixed for electron microscopy to determine the method of schizogonie development. Schizogony takes place by endopolygeny characterized by marked enlargement of the parasite nucleus, formation of nuclear lobes, presence of numerous spindles with adjacent pairs of centrioles along the nucleus, and simultaneous formation of daughter merozoites in the cytoplasm adjacent to the spindle poles. Endopolygeny in S. cruzi differs from that in other Sporozoa in that merozoite anlagen are seen in the cytoplasm before any nuclei divide. The resultant merozoites continue development and, when mature, resemble other sporozoan zoites. Upon release from the host cell into capillaries, they travel to muscle tissue to continue the life cycle by forming sarcocysts.
Effects of Neurochemicals upon a Dinoflagellate Photoresponse*
Authors: FORWARD RICHARD B.
Published: May 2007

SYNOPSISPhotoresponsiveness byGymnodinium splendensLebour was monitored quantitatively by a microscope‐television system. Exposure to the catecholamines DOPA and Dopamine caused a decrease in light sensitivity, while 0.01 mM norepinephrine, epinephrine, or isoproterenol did not affect photoresponsiveness. Classical catecholamine blocking agents, dichloroisoproterenol, propranolol, and dibenzyline, and an inhibitor of DOPA synthesis, α‐methyl‐ρ‐tyrosine, caused an increase in sensitivity. In addition, acetylcholine and an inhibitor of acetylcholinesterase activity, eserine, caused an increase in sensitivity, while an inhibitor of acetylcholine action atropine, had the opposite effect. These experiments suggest thatG. splendensmay have an antagonistic catecholamine‐cholinergic system which participates in regulating photosensitivity.
Plasmodium durae Herman from the Introduced Common Peafowl in Northern Nigeria
Authors: LAIRD MARSHALL
Published: May 2007

SYNOPSIS. Plasmodium (Giovannolaia) durae Herman was originally described from Kenya, the type host being the common turkey, Meleagris gallopavo Linnaeus. There are no field records of this association outside of Africa, where the parasite, herein reported from another introduced and domesticated bird (the common peafowl, Pavo cristatus Linnaeus), was recently listed from 2 native Phasianidae of the genus Francolinus. The justification for the present identification is submitted against background data concerning malaria parasites from turkeys and other Galliformes in Africa and elsewhere, and restraint is urged in describing yet more “new species” of avian Plasmodium belonging to morphologically close taxa within Novyella and Giovannolaia. A near relative of P. durae, Plasmodium dissanaikei de Jong, is transferred from the former subgenus to the latter one.
Transformation in Tetrahymena pyriformis: Description of an Inducible Phenotype*†
Authors: NELSEN E. MARLO , DEBAULT LAWRENCE E.
Published: May 2007

SYNOPSIS. Transformation of Tetrahymena pyriformis to a rapid‐swimming (presumably dispersal) form can be induced by washing cells and suspending them in distilled H2O, Dryl's solution or 10 mm Tris. Transformation is possible with high efficiency in mass cultures of axenically grown cells within ∼ 5 h at 30 C. The radically different phenotype produced during transformation is characterized by a more elongate body form, increased numbers of somatic basal bodies and cilia, a long caudal cilium and oral membranelles positioned beneath the cell surface. DNA quantities characteristic of G1, S, and G2 cells are found in these transformed ciliates, suggesting that achievement of a particular stage in the DNA‐division cycle is not a prerequisite for transformation. Preliminary observations on cells belonging to syngens 2–12 indicate that they also have a capacity to form a caudal cilium, but that the amicronucleate strain GL‐C does not. Possible relevance of the transformed phenotype for taxonomy of Tetrahymena is discussed.
Differences in the Life Cycles Between a Vaccine Strain and an Unmodified Strain of Babesia bovis (Babes, 1889) in the Tick Boophilus microplus (Canestrini)*
Authors: STEWART N. P.
Published: May 2007

SYNOPSIS. Developmental forms of 2 strains of Babesia bovis (Babes) were studied in the tick vector Boophilus microplus (Canestrini). One strain (designated T) was shown to be infective for the tick, and the other (NT) to have lost infectivity for the tick, because of repeated blood passaging in cattle.

Parasites of the 2 strains in gut contents of adult female ticks were similar during the first 16 h post‐repletion (PR), but thereafter their structure differed. From 16–64 h PR, the majority of T strain parasites were spherical and without processes. During the next 32 h elongate forms and vermicules developed. Fission bodies were seen within epithelial cells of the gut by 96 h PR. T‐strain parasites in gut contents decreased in number from ∼ 96 h and were difficult to find at 144 h, the time of the final observation.

In contrast, NT strain parasites were plentiful throughout the period of observation. They were predominantly spherical, ranging in diameter from 1.5 to 15 μm. Forms with obvious processes measuring up to 81 μm in length were seen in large numbers at seemingly regular intervals from 16–144 h PR, suggesting that a process of development and divisions was being repeated. No vermicules or fission bodies were seen.

T‐strain, but not NT strain parasites, were seen in hemolymph and ova of the ticks and in their larval progeny. It is suggested that continuous blood passaging of the NT strain had resulted in selection of parasites incapable of penetrating gut epithelial cells of the tick.
Plasmodium falciparum in Culture: Improved Continuous Flow Method*
Authors: TRAGER WILLIAM
Published: May 2007

SYNOPSIS.

A new design of flow vessel provides a method for continuous culture of P. falciparum in a settled layer of human erythrocytes with a slow flow of culture medium over them. The parasitemia is kept fluctuating from ˜ 1%, just after addition of fresh erythrocytes. to ˜ 10%, 2 or 3 days later. Each vessel provides each week 3 harvests, each containing ˜ 0.6–1 × 109 parasites.
Acid and Neutral Hydrolases in Trypanosoma cruzi. Characterization and Assay*
Authors: AVILA JOSE LUIS , CASANOVA MARIA ARGELIA , AVILA ANGELA , BRETANA ANTONIO
Published: May 2007

SYNOPSIS

Twelve acid hydrolases, 4 near‐neutral hydrolases and alkaline phosphatase were demonstrated in 0.34 M sucrose homogenates of Trypanosoma cruzi strain Y: p‐nitrophenylphosphatase and α‐naphthylphosphatase, with optimum pH at ˜ 6.0; α‐galactosidase, β‐galactosidase, β‐glucosidase, N‐acetyl‐β‐glucosaminidase, cathepsin A and peptidase I and III, with optimum pH between 5.0 and 6.0: and arylsulfatase cathepsin D, α‐arabinase and α‐mannosidase with optimum pH at ˜ 4.0 α‐Glucosidase, gluccse‐6‐phosphatase and peptidase II had optimum pH at ˜ 7.0. β‐Glycerophcsphatase had a broad pH‐activity curve from 4.0 to 7.4, with maximum activity at pH 7.0. The main kinetic characteristics of these enzymes and their quantitative assay methods were studied.

No activity was detected for α‐fucosidase, β‐xylosidase, β‐glucuronidase, elaidate esterase. acid lipase, and alkaline phospho‐diesterase.
Interdependence of Cell Cycle Events in Tetrahymena thermophila: Formation of Contractile Vacuole Pore and Fission Gap in Ciliary Meridians*
Authors: NG STEPHEN F.
Published: May 2007

SYNOPSIS The formation of the contractile vacuole pore (CVP) in Tetrahymena thermophila. genotype molb/molb is temporally and spatially associated with the formation of the fission gap in the CVP meridian. New CVPs arise when fission gaps appear in CVP meridians, the new pores being found anterior to the gaps. When, however, CVP meridians are rotated 180°, the fission gaps develop late. In more than 1/3 of the 180°‐rotated CVP meridians, the new CVPs are formed before the appearance of the fission gap. Evidently, the appearance of the gap is not a prerequisite for CVP formation. Nevertheless, mutants exist in which the absence of fission gap and CVP are correlated in some cases and in which the presence of supernumerary fission gap and CVP are correlated in other instances. It is suggested that the 2 developmental events, although not causally related to each other, may be controlled by a common morpho‐genetic signal. This commits a certain site (mid‐body) along a ciliary meridian to develop the fission gap as well as the CVP; however, after this step of commitment, the appearance of the fission gap is delayed in 180°‐rotated CVP meridians.