bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Viscosity on Formation and Sedimentation of Polytomella agilis Vertical Aggregates*
Authors: GITTLESON STEPHEN M. , ROGERS MICHAEL 
Published: May 2007

SYNOPSISThe response of vertical aggregates of Polytomella agilis to increased viscosity of the medium indicates that viscous resistance of the medium is a critical factor controlling the formation and sedimentation of protozoan aggregates. Aggregate formation time increased from 20 sec to 6.5 min as viscosity was increased 1.72 times. Sedimentation rate decreased about 140 μm/sec for each 10% increment in viscosity. Although there was a 60% decrease in speed of falling aggregates when relative viscosity was increased from 1.0 to 1.6, individually swimming P. agilis decreased less than 22% in speed even at a relative viscosity of 1.84 where aggregates did not form. Cells continued to accumulate near the surface by negative geotactic swimming after vertical aggregation ceased. Vertical aggregation is a cyclic process composed of 4 phases: a) accumulation‐aggregation; b) aggregate sedimentation; c) ablation and dispersal; and d) negative geotaxis. Phase d is unique to motile microorganisms and only in such populations is vertical aggregation continuously selfperpetuating. Phases a‐c occur with both motile and nonmotile bodies and are dependent upon viscous forces of the medium.
Division and Formation of the Macronuclei of Keronopsis rubra*
Authors: RUTHMANN AUGUST 
Published: May 2007

SYNOPSISThe hypotrichous ciliate Keronopsis rubra has ∼10 micronuclei and ∼100 small macronuclei. DNA synthesis proceeds synchronously in all macronuclei in the 2nd half of the cell cycle which takes about 24 hr at room temperature. A G2 phase is virtually absent, each nucleus dividing as soon as the replication band has passed over it. The micronuclear S phase falls within macronuclear G1 and is followed by immediate division. Comparative cytophotometric measurements of Feulgen‐stained preparations indicate that the DNA content of G1 macronuclei is scattered widely in a skewed normal distribution, with a peak corresponding to the DNA content of a G1 micronucleus. Measurements of dividing macronuclei indicate unequal distribution of DNA between daughter nuclei and lead to the conclusion that the units of assortment must be smaller than whole genomes unless the micronucleus is polyploid. After conjugation, a large macronuclear anlage with threads resembling split prophase chromosomes is formed. The threads condense and pass singly into the cytoplasm where they are thought to give rise to the numerous small macronuclei of the vegetative cells.
Localisation Intracellulaire et Caracterisation de Deux Types de Malate Deshydrogénase chez Trichomonas vaginalis Donné, 1836
Authors: METENIER G. BRUGEROLLE et G. 
Published: May 2007

RESUME. Deux formes d'activité malate‐deshydrogénasique (MDH) ont été séparées après centrifugation en gradient de densité, chez Trichomonas vaginalis: une forme est soluble et l'autre est liée aux “grains denses'’cytoplasmiques. Ces 2 MDH (NAD dépendantes) ont des pH d'activité optimale et des constantes de Michaelis différents; on peut les séparer par électrophorèse sur gel d'amidon ou de polyacrylamide (présence d'isoenzymes).SYNOPSIS. Two forms (isozymes) of malate dehydrogenase (MDH) of Trichomonas vaginalis cells were isolated by centrifugation on sucrose density gradient. One form is located in the soluble fraction and the other is linked to the cytoplasmic “dense granules.”The optimum pH and Km values are different for the 2, NAD‐dependent dehydrogenases, which can be separated by starch or polyacrylamide gel electrophoresis.
Eigenschaften des Elektronentransportsystem von Mitochondrien des Protisten Acanthamoeba castellanii Neff. I. Zum Einfluß von Hemmstoffen auf verschiedene Akzeptorsysteme, getested mit einer modifizierten Thunbergtechnik
Authors: FOUQUET H. 
Published: May 2007

ZUSAMMENFASSUNG. Die Reduktionsgeschwindigkeit künstlicher Elektronenakzeptoren wurde mittels einer modifizierten Thunbergtechnik in Gegenwart isolierter Mitochondrien des Protisten Acanthamoeba castellanii Neff photometrisch gemessen. Die mit verschiedenen Elektronenakzeptoren und Atmungsketteninhibitoren gewonnenen Meßergebnisse erlauben uns folgendes Bild von der Konstitution der Atmungskette zu entwerfen: a) Der Elektronentransport läuft mindestens bis zum Cytochrom b/Coenzym Q‐Komplex auf zwei verschiedenen Wegen ab. b) Eine Stimulierung sowohl des Succinat‐Jodnitrotetrazolium‐chlorid als auch des NADH‐Ferricyanid Reduktasekomplexes unter dem Einfluß von Antimycin A läßt vermuten, daß in der Atmungskette dieses Protisten gewisse Nebengleise des Elektronentransports besonders gangbar sind.SYNOPSIS. The reduction of artificial electron acceptors by isolated mitochondria of Acanthamoeba castellanii was measured by a modified Thunberg technic. The results with different electron acceptors and respiratory chain inhibitors suggest the following scheme for the constitution of the respiratory chain: a) the chain is divided into 2 different sequences, at least up to the cytochrome b/coenzyme Q complex. b) As seen from the stimulation of the succinate‐iodonitrotetrazolium chloride and NADH‐ferricyanide reductase complexes by antimycin A, certain alternate pathways of electron transport become more important than the normal one.
Leishmania in the Chick Embryo. II. Effects of Inoculum Size, Strain Origin, and Stage Injected and Infectivity of Embryo‐Derived Parasites for Hamsters*
Authors: HOLBROOK THOMAS W. , STAUBER LESLIE A. 
Published: May 2007

SYNOPSIS. Amastigotes of Leishmani donovani strains 2S, 3S, 3K, Hm, Gm, and Et were inoculated intravenously into 14‐day chick embryos. The course of infection was followed by examinations of liver impression smears. With strain 33 at 33 C incubation, there was a 29‐fold increase at 6 days postinfection when the inoculum contained ∼4 × 106 amastigotes, but only a ∼6.3‐fold increase when ∼64 × 106 parasites were injected. Infection courses of several geographic strains were compared at 30, 33, and 35 C incubation. Although the results were variable, Sudan strains 2S and 3S appeared to be separate isolations of a single strain. The Burma (Et), Kenya (3K), and Mediterranean (Hm, Gm) strains appeared to be distinct, but confirming evidence of their distinctness should be sought using serologic, epidemiologic, clinical, and biochemical criteria. Strains 2S and 3S multiplied best at 33 C or below, but the embryos usually failed to survive at 28 or 30 C. Multiplication was inhibited partially at 35 C and completely at 37 C.Inoculation of strain 3S promastigotes into chick embryos resulted in a loss of parasites in 1 hr to 2 days postinfection. Only amastigotes were seen in embryos incubated at 28 and 33 C for 4 days.Hamsters infected with parasites passaged once in chick embryos died at median postinoculation times that were closely comparable to those noted among hosts infected with amastigotes from hamster spleen.
Oxidation of NADH in a Coupled Oxidase‐Peroxidase Reaction and its Significance for the Fermentation in Rumen Protozoa of the Genus Isotricha
Authors: PRINS R. A. , PRAST E. R. 
Published: May 2007

SYNOPSIS. Cell‐free extracts of the anaerobic rumen ciliate Isotricha prostoma possess a strong NADH oxidase activity. Evidence for H2O2 as an intermediary product during oxidation of NADH has been obtained. Gatalase activity could not be demonstrated but hydrogen peroxide is removed by a rate limiting NAD peroxidase.In addition to oxygen several other compounds such as ferricyanide, cytochrome c, menadione and certain dyes may function as electron acceptors during oxidation of NADH. The ferricyanide reductase activity in the Isotricha extracts strongly resembles that of the mitochondrial enzyme from mammalian sources in a number of characteristics.Partial inhibition of NADH oxidase activity was obtained with the following chelating agents: hydroxylamine, diethyl dithiocarbamate, 2,9‐dimethyl‐1,10‐phenanthroline (DMPH), and 2‐thenoyl trifluoroacetone, whereas citrate, tartrate, pyrophosphate, salicylaldoxime, EDTA and 8‐hydroxyquinoline had no effect. The peroxidase was blocked completely by 0.42 mM DMPH and this inhibitor was used to block the enzyme in whole cells in experiments on oxygen toxicity. The oxidase was largely insensitive to azide, KCN, and uncouplers. Antimycin A and rotenone caused a partial inhibition of the oxidase when added in very high concentrations. ATP formation occurred during oxidation of NADH, and P/O ratios were 0.1–0.35. Addition of small amounts of oxygen to intact ciliates led to a decrease in the production of hydrogen and butyrate, while the production of acetate was increased and no change in the lactate formation was seen. This shift in fermentation end‐products possibly is caused by a competition of oxygen for NADH.
Cochleomeritus emersoni sp. n. (Protozoa, Apicomplexa), a Lecudinid Gregarine from the Pacific Ocean Polychaete Diopatra ornata Moore, 1911*
Authors: LEVINE NORMAN D. 
Published: May 2007

SYNOPSISThe gregarine Cochleomeritus emersoni sp. n. is described from the intestine of the marine polychaete Diopatra ornata from the Pacific Ocean off Point Hueneme, California.
Grellia gen. n. for Eucoccidium of Grell (1953) Preoccupied*
Authors: LEVINE NORMAN D. 
Published: May 2007

SYNOPSIS
Grellia
gen. n. is established for the genus Eucoccidium of Grell (1953) preoccupied, and the classification of the apicomplexan order Protococcidiorida Kheisin, 1956 is reviewed, giving diagnoses, type species and a list of species. Grelliidae fam. n. is established for the genera Grellia, Coelotropha, Myriosporides and Defretinella.
Development of Hepatozoon griseisciuri in Cultured Squirrel Cells*
Authors: HENDRICKS LARRY D. , FAYER RONALD 
Published: May 2007

SYNOPSISSporocysts of Hepatozoon griseisciuri obtained from laboratory‐reared spiny rat mites (Echinolaelaps echidninus) and laboratory‐reared squirrel mites (Haemogamasus reidi) were made bacteria‐free and incubated in trypsin‐bile for 30 min at 37 C to release sporozoites. Hepatozoon griseisciuri sporozoites were inoculated into monolayer cultures of primary adult squirrel kidney (PSK) cells and cell line cultures of neonatal squirrel kidney (SK), heart (SH), and spleen (SS) cells. Extracellular sporozoites underwent flexing, gliding, and pivoting movements similar to other coccidian sporozoites. Sporozoites entered cells in all the cultures used and were found intracellularly as early as 1 hr and as late as 10 days after inoculation. In SK, SH, and SS cells, development proceeded only to the trophozoite stage. In PSK cells, immature schizonts and mature schizonts containing 12–40 merozoites were present from 5 through 10 days after inoculation. The finding of pairs of intracellular organisms within a single parasitophorous vacuole in PSK cells suggested that endodyogeny or limited schizogony had occurred.
Tracheloraphis haloetes sp. n. (Ciliophora, Gymnostomatida): Description and a Key to Species of the Genus Tracheloraphis
Authors: BORROR ARTHUR C. 
Published: May 2007

SYNOPSISTracheloraphis haloetes sp. n. occurred in a water sample from a Bahama industrial salt works (S = 82 ppt). Its measurement, shape, ciliation (pericytostomal, locomotory, and nonmotile), internal structure, and behavior are described. A simple binary key is used to indicate its similarities to and differences from its congeners. The key is based on characteristics of nuclear configuration, glabrous zone morphology, body shape, and patterns of ciliation.
An Electron Microscope‐Cytochemical Method for Differentiating Membranes of Host Red Cells and Malaria Parasites*
Authors: SEED THOMAS M. , AIKAWA MASAMICHI , STERLING CHARLES R. 
Published: May 2007

SYNOPSISLimiting membranes of malaria parasites and host red cells stain differently when exposed to positively charged iron colloid. Negatively charged red cell membranes avidly bind colloid, whereas parasite membranes do not. This selectivity in colloidal iron uptake by the 2 types of membranes can be utilized as an aid in discerning the amounts of contaminating host cell membranes in “free” malaria parasite preparations and in related cell‐free membrane extracts.
Ultrastructural Architecture and Organization of the Spore Envelope during Development in Thelohania bracteata (Strickland, 1913) after Freeze‐Etching*
Authors: LIU T. P. , DAVIES D. M. 
Published: May 2007

SYNOPSISAn ultrastructural study was made of the spore envelope during development in the microsporidan, Thelohania bracteata. The frozen‐etched outer (convex) face of the relatively thin spore coat in the earliest immature stage of development has a granular structure in regular array. The inner (concave) face bears particles as well as depressions arranged in a net‐like pattern. The mature spore coat has a substructure of numerous microfibers, ∼8 nm in diameter, arranged in a matrix and forming thin layers which run parallel to the spore surface. The mature spore coat possesses both outer and inner limiting layers. The outer (convex) face of the outer limiting layer is granular. The convex face of inner limiting layer bears many particles as well as many long, narrow depressions. The concave face of the inner limiting layer carries many stud‐like projections, ∼40 nm long and 30 nm high, which are complementary to the depressions observed on the convex face. In addition, the concave face has subunits ∼15 nm in diameter, apparently arranged in a hexagonal pattern with a center to center distance of ∼18 nm. The change in size of these projections, depressions, and subunits presumably is related to spore maturation.
DNA and RNA Syntheses by Intraerythrocytic Stages of Plasmodium knowlesi*
Authors: CONKLIN K. A. , CHOU S. C. , SIDDIQUI W. A. , SCHNELL J. V. 
Published: May 2007

SYNOPSISIncorporation of the nucleic acid precursors, orotic acid, adenosine, thymidine, and uridine, was studied in various stages of intraerythrocytic Plasmodium knowlesi from infected rhesus monkeys. Incubation of the parasitized erythrocytes with the precursors was for 3 hr periods using a plasma‐free culture medium. The samples containing primarily rings, early trophozoites, or late trophozoites incorporated orotic acid, adenosine, and uridine into RNA; however, these stages exhibited negligible or very low levels of incorporation of any of the precursors into DNA. The sample containing late trophozoite and schizont stages incorporated orotic acid, adenosine, and uridine into RNA, and orotic acid, adenosine, and very low levels of thymidine into DNA. These results indicate that DNA synthesis (the S phase of the cell cycle) occurs very close to the time of nuclear division, and that either the G1 or G2 phase is very short in P. knowlesi.It was also observed that adenosine and orotic acid, 2 precursors which are incorporated into both DNA and RNA, are utilized differently by the intraerythrocytic parasites. Incorporation of orotic acid into RNA and DNA and adenosine incorporation into DNA were continuous for the entire incubation period, whereas incorporation of adenosine into RNA was very low during the last 2 hr of each period. It was further demonstrated that the parasites utilized exogenous uridine for synthesis of RNA, and that the older parasite stages incorporated thymidine into DNA.
Observations sur des Nyctothères des genres Sicuophora de Puytorac & Grain, Metasicuophora gen. n. et Parasicuophora Albaret, Ciliés parasites de Batraciens Anoures
Authors: ALBARET JEAN‐LOUIS 
Published: May 2007

RESUMEL'ampoule rectale de quelques Batraciens Anoures d'Afrique et d'Asie héberge 4 espèces de Nyctothères caractèrisèes par la prèsence d'une ventouse sur toute la face infèrieure et une topographie ciliaire presque identique. L'observation des formations squelettiques polysaccharidiques montre que ces èlèments constituent un critère taxonomique complèmentaire ayant une signification phylogènètique, Chez Sicuophora macropharyngea (Bezzenberger 1904) comb. n. et S. xenopi de Puytorac & Grain, 1968, les plaques de la ventouse forment un pavage. Les plaques marginales sont acuminèes. Metasicuophora petteri gen. n., sp. n. est une espèce de grande taille, très aplatie. Les plaques marginales de la ventouse sont èlargies à leur extrèmitè et l'armature squelettique de la face supèrieure est très dèveloppèe. Chez Parasicuophora xavierae sp. n., les èlèments squelettiques de la ventouse sont constituès par des filaments identiques à ceux observès chez P. mantellae Albaret, 1968.SYNOPSISThe rectum of several African and Asian anuran amphibians harbors 4 species of nyctotherid ciliates characterized by the presence of a sucker on the entire lower surface, and a nearly identical ciliary distribution. Observations of the skeletal structures made up of polysaccharides indicate that these elements constitute a complementary taxonomic criterion with a phylogenetic significance. In Sicuophora macropharyngea (Bezzenberger 1904) comb. n. and S. xenopi de Puytorac & Grain, 1968, the plaques of the sucker have a pavement‐like arrangement and the marginal plaques are pointed. Metasicuophora petteri gen. n., sp. n. is a large, very flattened species. The marginal plaques of the sucker have terminal enlargements and the skeleton of the upper surface is well developed. In Parasicuophora xavierae sp. n., the skeletal elements of the sucker consist of filaments identical to those observed in P. mantellae Albaret, 1968.
Crystalloid Inclusions in Species of Leucocytozoon, Parahaemoproteus, and Plasmodium*†
Authors: TREFIAK WILLIAM D. , DESSER SHERWIN S. 
Published: May 2007

SYNOPSISCytoplasmic vacuoles seen in methanol‐fixed, Giemsa's‐stained ookinetes of Leucocytozoon simondi, Parahaemoproteus fringillae and Plasmodium gallinaceum, when studied with the electron microscope, were found to correspond with crystalloid inclusions of similar structure, particle size, and arrangement. Cytochemical examination of these “crystalloids” revealed their lipid‐protein nature. Morphologically similar inclusions were found also in ookinetes of Leucocytozoon ziemanni and Parahaemoproteus velans. In L. simondi, crystalloid is formed rapidly after fertilization, from amorphous electron dense material seen in mature macrogametocytes. The arrangement and distribution of crystalloids in the zygote, ookinete, oocyst, and sporozoite are described. On the basis of differences in structure and particle size, it is proposed that the crystalloid inclusions in Haemosporina be divided into 2 types. Type I—lipid‐protein in nature, characterized by electron dense irregularly spherical particles, 25–40 nm in diameter, with individual particles not invested by membrane. Type II—probably virus, characterized by electron dense, irregularly spherical, membrane‐bounded particles, with a diameter usually greater than 40 nm.
A Comparative Study of Gametocyte Ultrastructure in Avian Haemosporidia*
Authors: STERLING CHARLES R. , AIKAWA MASAMICHI 
Published: May 2007

SYNOPSISThe fine structure of gametocytes of 3 avian haemosporidian parasites Plasmodium gallinaceum, Haemoproteus columbae, and Leucocytozoon simondi has been studied and compared by electron microscopy. The gametocytes of all 3 species are bounded by a 3‐layered limiting membrane system, possess a cytostome during some portion of their residence within host cells, and their sex can be distinguished by both nuclear and cytoplasmic characteristics. L. simondi differs most significantly from P. gallinaceum and H. columbae in possessing large intranuclear granules, mitochondria associated with pocket infoldings of the nuclear envelope near the atypical centriole complex and compartmentalization of the cytoplasm by segments of closely aligned unit membranes. Further, the cytostome of L. simondi does not appear to be a persistent structure as in the other 2 species and pigment is not present within food vacuoles. L. simondi also is capable of infecting a wider variety of host cells and within leukocytes produces striations of the host nucleus and an apparent spiral banding of the host cell surface. The comparison of P. gallinaceum, H. columbae, and L. simondi gametocytes by electron microscopy leads to the conclusion that Plasmodium and Haemoproteus are more closely related to each other than either of them is on Leucocytozoon.The terminology used to describe certain organelles within the gametocyte's cytoplasm has been reexamined and the relationship of the nucleolus to parasite maturation also is described.
Differentiation During Encystment and Excystment in Oxytricha fallax*
Authors: GRIMES GARY W. 
Published: May 2007

SYNOPSISDuring encystment of Oxytricha fallax, a wall composed of 4 distinct layers, each derived from a different kind of endoplasmic vesicle, is formed between the 2 unit membranes that cover the vegetative cell. Numerous autophagic vacuoles arise in the endoplasm and later (during excystment undergo internal changes comparable to those characteristic of food vacuoles. Mitochondria aggregate into a band. The 2 macronuclei fuse and their nucleoli become homogeneous. Except for the 2 cell membranes, all visible cortical structures, including cilia, kinetosomes, and microtubules, disappear. Despite the absence of visible ciliature in the mature cyst, the various primordia of the normal vegetative ciliature arise during excystment in the same positional relations to one another as is characteristic of developments during cell division.
Incorporation of Radioactive Pyrimidine Nucleosides into DNA and RNA of Eimeria tenella (Coccidia) Cultured In Vitro*
Authors: OUELLETTE CAROL A. , STROUT RICHARD G. , McDOUGALD LARRY R. 
Published: May 2007

SYNOPSISAutoradiographic methods were used to study the incorporation of tritiated cytidine, thymidine, and uridine into asexual stages of Eimeria tenella cultured in embryonic chick kidney cells. Developing parasites did not incorporate 3H‐thymidine either when host cells were labeled prior to infection or when the cultures were labeled for 30 min, 48–72 hr after infection. Continuous exposure of infected cultures to 3H‐thymidine for up to 18 hr resulted in light labeling of cell cytoplasm and schizonts. 3H‐cytidine and 3H‐uridine were incorporated into parasites developing in cultures that were labeled before infection. When the cultures were labeled for 30 min, 48–72 hr postinfection and fixed immediately, schizonts were labeled lightly with 3H‐cytidine but contained dense accumulations of 3H‐uridine.
Competition of Ethionine and Methionine for Aminoacyl‐tRNA Formation in an In Vitro System from Ochromonas danica*
Authors: ZIV E. , HOCHBERG A. , DEGROOT N. , RAHAT M. 
Published: May 2007

SYNOPSISAminoacyl‐tRNA synthetase and tRNA were isolated from the chrysomonad Ochromonas danica. The mutual effect of methionine and ethionine, and the effect of other amino acids on methionyl‐ and ethionyl‐tRNA formation, were tested in an in vitro system.The tRNAMet had a similar accepting capacity for either methionine or ethionine. Ethionine and methionine, but none of the other amino acids tested, competed for the same aminoacyl‐tRNA synthetase. The Km of methionine was 0.88 × 10–5 M, and that of ethionine 5 × 10–4 M. Ethionine inhibited methionine binding; Ki 3.4 × 10–4 M. The respective values in a similar system isolated from E. coli were 2.2 × 10–5, 1.95 × 10–3, and 1.95 × 10–3.
Selenidium fauchaldi sp. n. and S. telepsavi (Stuart) comb. nov. (Protozoa, Apicomplexa), Gregarines from Polychaetes*
Authors: LEVINE NORMAN D. 
Published: May 2007

SYNOPSISGregarine Selenidium fauchaldi sp. n. is described from the intestinal lumen of the polychaete Phragmatopoma californica (Fewkes, 1889) in the intertidal zone of the Pacific Ocean on Santa Catalina Island, California. In addition, the new combination Selenidium telepsavi (Stuart, 1871) comb. nov. is introduced for the gregarine originally described as Monocystis telepsavi from the polychaete Telepsavus castarum in the Black Sea.