bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyst‐Induced Toxoplasmosis in Cats*
Authors: DUBEY J. P. , FRENKEL J. K. 
Published: May 2007

SYNOPSIS. The life cycle of Toxoplasma gondii is described from cats orally inoculated with Toxoplasma cysts. Five new structural stages of Toxoplasma designated as “types” A‐E were found in the epithelial cells of the small and large intestine. Type A is the smallest of all 5 intestinal Toxoplasma types. It occurs as collections of 2‐3 organisms in the jejunum 12–18 hr after infection. Type B organisms are characterized by a centrally located nucleus, a prominent nucleolus and dark blue cytoplasm giving rise to the appearance of bipolar staining with Giemsa. Type B occurs 12–54 hr after infection and appears to divide by simple endodyogeny and by multiple endodyogeny (endopolygeny). Type C organisms are elongate with subterminal nuclei and strongly PAS‐positive cytoplasm. They occur at 24–54 hr and divide by schizogony. Type D organisms are smaller than type C and contain only a few PAS‐positive granules. They occur from 32 hr to 15 days after inoculation and account for over 90% of all parasites in the small intestine during this time. Three subtypes divide by endodyogeny, schizogony and by splitting of their merozoites from the main nucleated mass without leaving a residual body. Type E organisms resemble one of the subtype D which divide by schizogony, but they leave a residual body. They occur from 3–15 days after inoculation.Gametocytes occur thruout the small intestine but more commonly in the ileum 3‐15 days after infection. Male gametocytes contain on an average of 12 microgametes and comprise 2–4% of the gametocyte population. The prepatent period after cystinduced infection is 3–5 days with the peak oocyst production between 5–8 days and a patent period varying from 7–20 days.Variable numbers of trophozoites are present in the lamina propria of the small intestine and in the extra‐intestinal tissues within a few hr after inoculation. After 9–10 days cysts were seen in the heart and later in the brain.The lesions of toxoplasmosis are compared in newborn and weanling kittens and in adult cats after oral and subcutaneous inoculation with cysts. After the ingestion of cysts, newborn kittens developed enteritis, hepatitis, myocarditis, myositis, pneumonitis and encephalitis and were moribund by the 9th day. Kittens aged 2 weeks and older developed enteritis, myocarditis, encephalitis and myositis but often survived; adult cats usually remained asymptomatic. After subcutaneous inoculation of cysts, newborn and weanling kittens died of acute toxoplasmosis with severe pneumonia, myocarditis, encephalitis and hepatitis.
The Physiology of Astrephomene gubernaculifera1
Authors: BROOKS A. E. 
Published: May 2007

SYNOPSIS. A comparative physiologic study of 4‐ and 7‐chromosome strains of Astrephomene gubernaculifera was done. The vitamins p‐aminobenzoic acid, nicotinamide, biotin, thiamin HCl and vitamin B12 were tested for their ability to support growth. Only vitamin B12 was required for active growth altho the presence of thiamin HCl was necessary to produce structurally typical colonies. Astrephomene will not grow in the absence of an exogenous source of carbon. Of the 36 carbon sources tested, only pyruvate, butyrate, succinate and acetate permitted active growth. Sodium acetate was the best.Strains grew within the initial pH range of 5.0–7.5. At pH values above 8.0 growth declined rapidly. When media were buffered with TES (N‐tris [hydroxymethyl]methyl‐2‐aminoethane‐sulfonic acid) at an initial pH of 6.8 growth was enhanced. The organism grew at 15–40 C. Growth in the dark was slightly less than that in the light.
Structure of Monocercomonas sp. as Revealed by Electron Microscopy*
Authors: MATTERN CARL F. T. , HONIGBERG B. M. , DANIEL WENDELL A. 
Published: May 2007

SYNOPSIS. Monocercomonas shares many fine‐structural features with all other trichomonads. These include the basic arrangement of the kinetosomes as well as of the recurrent and 3 anterior flagella. The pelta‐axostyle complex and the parabasal apparatus, i.e. the Golgi complex and the periodic filaments, also conform to the trichomonad pattern.Of interest with regard to the crucial evolutionary position of Monocercomonas, considered to represent the most primitive trichomonad type, is the fact that it has some structures in common with other Monocercomonadidae and Trichomonadinae and others in common with Devescovinidae and Tritrichomonadinae. Among the former organelles are the marginal lamella and the costal base, and among the latter, the comb‐like organelle situated between the infrakinetosomal body and parabasal filament 2 as well as the infrakinetosomal body. No traces of either costa or undulating membrane have been noted, but a complex structure homologous to the marginal lamella of Hypotrichomonas and Trichomonadinae is found underlying the short anteriormost portion of the recurrent flagellum that is attached to the body surface.Observations of sections of selected division stages indicate the potential of parental kinetosomes #1 and #3 to become daughter kinetosome #2.
A Note on Sporozoa of Undetermined Taxonomic Position in an Armadillo and a Heifer Calf
Authors: LAINSON R. 
Published: May 2007

SYNOPSISA sporozoan parasite of undetermined taxonomic position is described in the nine‐banded armadillo,Dasypus novemcinctus, from British Honduras, Central America. Schizonts, giving rise to approximately 60 merozoites, are produced in the parenchyma cells of the liver and in the endothelial cells of the brain capillaries: rupture of the schizonts stimulates conspicuous foci of inflammatory response. No sexual stages were observed. A similar parasite is recorded in the lung and liver of a heifer calf,Bos taurus, from England. The possible relationship of these parasites within the Sporozoa is discussed.
Mirex and Aroclor® 1254: Effect on and Accumulation by Tetrahymena pyriformis Strain W*
Authors: COOLEY NELSON R. , KELTNER JAMES M. , FORESTER JERROLD 
Published: May 2007

SYNOPSISEffects of 2 toxicants, Mirex and Aroclor 1254, on Tetrahymena pyriformis strain W in axenic cultures were investigated. Mirex is a chlorinated hydrocarbon effective against the fire ant, and Aroclor 1254 is a compound structurally related to DDT and used extensively in various industrial processes. Both toxicants reduced growth rates and population densities of T. pyriformis grown at 26 C generally in proportion to concentrations of the chemicals, their effects becoming statistically significant (P < 0.05) at 0.9 μg/liter for Mirex and 1.0 and 10.0 μg/liter for Aroclor 1254. Ciliates exposed to the toxicants for 7 days concentrated Mirex 193 × and Aroclor 60 × as compared to the initial concentrations of these compounds. It is suggested that the chief effect of the 2 toxicants on populations of T. pyriformis and of similarly responding ciliates in nature would be to reduce the availability of these protozoa as food organisms and nutrient regenerators. The ability of the ciliates to concentrate the tested compounds would permit the toxicants to enter into and to be translocated through aquatic food chains. In this manner the compounds could exert toxic effects at higher trophic levels.
The Stability of Cortical Phenotypes in Continuously Growing Cultures of Tetrahymena pyriformis*
Authors: FRANKEL JOSEPH 
Published: May 2007

SYNOPSISCortical features were analyzed in successive samples of continuously growing stock cultures of amicronucleate strains GL‐C and GL‐I, and in micronucleate strain WH‐6 (syngen 1, mating type I). Thirteen successive samples of strain GL‐C, representing a time span of 111 months, 5 samples of WH‐6 (43 months) and 2 samples of GL‐I (1 month) were examined. The observed range of commonly expressed ciliary row numbers (corticotypes) was 16–20 rows in strain GL‐C, 15–20 in strain GL‐I, and 16–20 in strain WH‐6. These ranges remained constant through time within each strain. The individual samples each included all or a large part of the total range observed in the strain, but the relative abundances of different corticotypes within this range shifted through time. The shifts appeared random, with no discernible trends.Mean contractile vacuole pore (CVP) position and number of CVP meridians were assayed in the 2 “GL” strains. Mean CVP position was an apparently stable character, with only slight fluctuations through time, while the distribution of number of CVP meridians was somewhat less constant. The CVP parameters of strains GL‐C and GL‐I were considerably different, and both of these strains were very different from the GL strain which had been studied by Nanney. In fact, these 3 “GL” strains have, among them, virtually the entire gamut of known CVP characteristics. The possible significance of these wide differences among strains presumed to be closely related is considered in the Discussion.
The Enzymic Synthesis of Dihydropteroate and Dihydrofolate by Plasmodium berghei
Authors: FERONE ROBERT 
Published: May 2007

SYNOPSIS. Cell‐free extracts of the rodent malaria parasite Plasmodium berghei synthesized dihydropteroate (H2pteroate) and dihydrofolate (H2folate) from 2‐amino‐4‐hydroxy‐6‐hydroxymethyl‐7,8‐dihydropteridine (hydroxymethyldihydropteridine) and p‐aminobenzoate (pAB) or p‐aminobenzoylglutamate (pABG). The reaction was demonstrated also in extracts of Plasmodium gallinaceum, Plasmodium lophurae and Plasmodium knowlesi, by the use of a microbiologic assay method and pABG as cosubstrate.Some of the properties of the enzymes involved were investigated in P. berghei preparations, utilizing a radioactive assay which measures the conversion of [7‐14C]pAB to [14C]H2pteroate. Apparent Km values of 0.28 μM for [7‐14C]pAB, 0.037 mM for pABG and 0.8 μM for hydroxymethyldihydropteridine were obtained. The reaction had absolute requirements for ATP and Mg++, and was stimulated by dithiothreitol. The enzymes required for the reaction were eluted together from Sephadex G‐200 columns in a molecular weight range of 200,000–250,000. In bacteria hydroxymethyldihydropteridine is converted 1st by a pyrophosphokinase to pyrophosphorylmethyldihydropteridine, and this compound is then condensed with pAB to form H2pteroate by H2pteroate synthetase. Both enzymic activities were demonstrated in P. berghei preparations and separated by DEAE‐Sephadex chromatography.The enzymic synthesis of H2pteroate by P. berghei is inhibited by several sulfonamides and diaminodiphenylsulfone (DDS). The latter compound is shown to be competitive with pAB, with a Ki value of 0.38 μM; pABG is also a competitive inhibitor. These data establish an enzymic basis of support for the evidence obtained in vivo which indicate that malaria synthesize their folate cofactors de novo. It is suggested that the antimalarial action of sulfonamides and DDS is due to their inhibition of plasmodial H2pteroate synthetase.
Observations on the Host‐Symbiont Relationships of Lagenophrys lunatus Imamura*
Authors: CLAMP JOHN C. 
Published: May 2007

SYNOPSISAn epizoic loricate peritrich, Lagenophrys lunatus Imamura, was found in North Carolina, Virginia, and Maryland on the exoskeleton of the palaemonid shrimp, Palaemonetes pugio, P. intermedius, P. vulgaris, P. paludosus, and Macrobrachium ohione. L. lunatus prefers to attach onto or near the appendages of the host where water movement over the exoskeleton is strongest. The symbionts depend for their food on particles of the host's food and phytoplankton swept to them by these water currents. They attach to other areas of the exoskeleton only when the preferred areas are filled. Trophic individuals are stimulated to undergo a special type of division in advance of the molt of the host that results in the evacuation from the old exoskeleton. Conjugation occurs en masse and has only been observed during molting of the host.
Macro‐ and Micronuclei of Tetrahymena pyriformis: A Model System for Studying the Structure and Function of Eukaryotic Nuclei*†
Authors: GOROVSKY MARTIN A. 
Published: May 2007

SYNOPSISThe macro‐ and micronucleus of Tetrahymena pyriformis are formed from a common diploid synkaryon during conjugation. Shortly after the 2nd postzygotic division, distinct morphologic and physiologic differences develop between the 2 nuclei. Micronuclei remain small, presumably diploid, and electronmicroscopic observations indicate that micronuclear DNA is contained in a dense, fibrous, chromosome‐like coil. Macronuclei contain considerably more DNA than micronuclei, and the DNA of the macronucleus is found largely in the chromatin bodies typical of ciliate nuclei. The functional differences between macro‐ and micronuclei in vegetative cells also are striking. The template activity of DNA in the micronucleus is highly restricted compared to that in the macronucleus. Micronuclei synthesize and contain little RNA, and do not contain either nucleoli or ribonucleoprotein granules. Macronuclei, on the other hand, synthesize and contain large amounts of RNA and have many nucleoli and ribonucleoprotein granules. Macro‐ and micronuclei also have distinct differences in the timing of DNA synthesis during the cell cycle and in the timing and mechanism of nuclear division. Finally, during conjugation the macronucleus becomes pycnotic and disappears while the micronucleus undergoes meiosis and fertilization, ultimately giving rise to new macro‐ and new micronuclei. In short, the macro‐ and micronuclei of Tetrahymena provide an excellent system for studying the molecular mechanisms by which the same (or related) genetic information is maintained in different structural and functional states.Methods have been devised to isolate and purify macro‐ and micronuclei of Tetrahymena in the hope of correlating differences in the nucleoprotein composition of these nuclei with differences in their structure and function. The DNAs of macro‐ and micronuclei have been found to differ markedly in their content of a methylated base, N6‐methyl adenine, and major differences in the histones of the 2 nuclei have been observed. Macronuclei contain histones similar to those found in vertebrate nuclei, while 2 major histone fractions seem to be missing in micronuclei. In addition, histone fraction F2A1 which is found in multiple, acetylated forms in macronuclei, is present only as a single, unacetylated form in micronuclei.
The Role of the Contractile Vacuole in the Osmoregulation of Tetrahymena pyriformis*
Authors: RIFKIN† JARED L. 
Published: May 2007

SYNOPSISThe relationship of cell size and contractile vacuole efflux to osmotic stress was studied in Tetrahymena pyriformis strain W, after transfer into fresh solutions iso‐ or hypoosmotic to the growth medium. Microscopic measurements of the cell and contractile vacuole dimensions, made with an image‐sharing ocular at 27 C, allowed the calculation of the cell size and shape and the vacuolar efflux rate which provide a measure of osmoregulation. The contractile vacuole cycles have no homeostatic oscillations. In 0.03–0.10 osmolar solutions, the cell size and shape are constant while the vacuolar efflux rate has an inverse linear dependence upon extracellular osmolarity. Regression analyses indicate that for cells with systole faster than 0.1 sec (the major part of the population), it is only the final diastolic volume of the contractile vacuole that is related to osmotic stress while the frequency of systole is independent of osmotic stress and has a constant period of 7.7 ± 0.2 sec. Therefore, osmotic stress upon Tetrahymena is regulated by a corresponding change in the filling rate of its contractile vacuole to allow an unaltered cell size and shape. Kinetic measurements of vacuoles during diastole fit the model (dV/dt = K1‐K2A), where (dV/dt) is the vacuolar filling rate and (A) is the vacuolar surface area. This dependence of vacuolar volume upon its surface area may be ascribed either to elastic components of the vacuolar membrane or to an increasing leakiness of this membrane during diastole. Mitochondrial inhibitors were used to observe the energy requirements of vacuolar operation and of intracellular secretion of water.
Phototaxis: Isolation of Mutant Strains of Chlamydomonas reinhardi with Reversed Sign of Response*†
Authors: HUDOCK G. A. , HUDOCK M. O. 
Published: May 2007

SYNOPSISThree mutant strains of Chlamydomonas reinhardi were isolated which are negatively phototactic under all conditions tested. Tetrad analysis indicated that these represent three separate, nuclear mutations. Two mutant genes are linked; the third is on a separate chromosome. At least two of the loci appear relatively far from their centromere(s).
A Marine Euplotes (Ciliophora, Hypotrichida) with Reduced Number of Prezygotic Micronuclear Divisions
Authors: LUEKEN WOLFGANG W. 
Published: May 2007

SYNOPSISIn contradistinction to the pattern of 3 prezygotic micronuclear divisions found in 10 species of Euplotes, a marine species resembling Euplotes crassus in structure, has only 2 divisions. This atypical division pattern was observed in all matings involving the 4 available mating types. The critical stages of the nuclear events are demonstrated by using special strains having the micronuclear DNA content and chromosome number only 1/2 the normal values. The employment of such strains facilitates differentiation between the stationary and migratory pronuclei in a given conjugant and determination of the times of conclusion of prezygotic divisions and of the pronuclear exchange.
Eimeria indianensis sp. n. and an Isospora sp. from the Opossum Didelphis virginiana (Kerr)*
Authors: JOSEPH THOMAS 
Published: May 2007

SYNOPSISTwo of 15 road‐killed opossums examined for coccidia were found to be infected with a hitherto undescribed species of Eimeria, herein named Eimeria indianensis. The oocysts were spherical (63%) or slightly subspherical (37%) with a double‐layered wall. The outer layer was ∼1.5 μm thick, yellowish, striated, and appeared rough and pitted on the surface. A micropyle was absent. The spherical oocysts were 16.3 (13–18) μm in diameter; the subspherical ones, 17.6 (15–18) × 16.4 (14–17) μm. The sporocysts measured 9.1 (8–10) × 6.2 (6–7) μm and contained a granular residuum. The sporozoites were elongate, measuring 13.4 (13–15) × 1.8 (1.6‐2.0) μm; no refractile globules were seen. The prepatent period was 10 days and the patent period ranged from 9–15 days.A few oocysts of an Isospora sp. were present in one opossum. It was not possible to confirm whether they were specifically of the opossum or of spurious origin.
The Fine Structure of the Phoront of the Apostomatous Ciliate, Hyalophysa chattoni*
Authors: BRADBURY PHYLLIS CLARKE 
Published: May 2007

SYNOPSISThe phoront of the apostomatous ciliate, Hyalophysa chattoni, is an encysted stage that is carried on the exoskeleton of its crustacean host until the ecdysis of the host. At molting the phoront rapidly metamorphoses to the feeding stage, excysts, and immediately begins to feed on exuvial fluid trapped in the cast‐off exoskeleton. The fine structure of the resting phoront resembles that of the preceding migratory stage, the tomite. A prominent ventral tuft of cilia, the ogival field, has vanished, and the trichocysts that paralleled the kinetics have disappeared. The dense inclusion bodies that were concentrated around the mouth and falciform fields have dispersed and greatly decreased in number. The cytoplasm and its membranous organelles do not appear visibly condensed or altered from the preceding stage in the life cycle. The phoront is merely quiescent instead of dormant.Unlike the few ciliate cysts previously examined by electron microscopy, the phoront's cyst is not divisible into separable layers. It resembles the loricae of certain suctoria in being formed principally of a fibrous substance, the outer surface of which has a paracrystalline pattern. The peduncle attaching the cyst to the crab's gill is a continuation of the cyst wall although its structure is somewhat modified.The most conspicuous innovation in the phoront's fine structure is the massive tracts of microtubules that run longitudinally through the macronucleus. The microtubules are in intimate contact with Feulgen‐positive chromatin masses which are crowded toward the periphery of the macronucleus.
Lysosomal Physiology in Tetrahymena. II. Effect of Culture Age and Temperature on the Extracellular Release of 3 Acid Hydrolases*
Authors: ROTHSTEIN THOMAS L. , BLUM J. J. 
Published: May 2007

SYNOPSISTetrahymena cultures were grown from a single inoculum and collected on 3 successive days corresponding to the log, transitional, and early stationary phases of growth. Cells were washed and incubated for 5 hr in a dilute salt solution. Intra‐ and extracellular activities of acid phosphatase, α‐glucosidase, and ribonuclease were assayed, and extracellular activities corrected for proteolytic degradation. A marked increase in the cellular content of acid phosphatase and significant decreases in α‐glucosidase and ribonuclease occurred with advancing culture age. The intracellular changes in enzyme activities during incubation were roughly similar for cells of all ages. Protein content did not change appreciably during incubation. Extracellular A255 release, monitored as an indication of the loss of RNA breakdown products, was at a minimum during incubation of transition cells. Significant quantities of all 3 acid hydrolases were released from cells of all ages except for ribonuclease from transition cells.The release of acid phosphatase and α‐glucosidase was approximately proportional to the initial cellular content of these enzymes for cells of different ages and in log cells the effect of temperature on the rates of release was described by the Arrhenius equation. Release of ribonuclease, however, was not proportional to its intracellular content nor did it vary with temperature according to the Arrhenius equation. The results suggest that acid phosphatase and α‐glucosidase are released via a first‐order process.
Results of Blood Transfusions from Donor Rabbits Infected with Eimeria stiedai to Recipient Coccidia‐free Rabbits*
Authors: FITZGERALD PAUL R. 
Published: May 2007

SYNOPSISBlood, withdrawn by heart puncture, from donor rabbits infected with Eimeria stiedai, was transfused by heart puncture, to uninfected recipient rabbits. Fifty‐nine of 76 young coccidia‐free recipients, given heparinized whole blood, erythrocytes or leucocytes from donors orally inoculated up to 27 days earlier, developed E. stiedai infections.
Labeling of Crithidia fasciculata DNA with [3H]Thymidine
Authors: SIMPSON AGDA M. , SIMPSON LARRY 
Published: May 2007

SYNOPSISAttempts at continuous labeling of Crithidia fasciculata DNA with [3H]thymidine led to a pulse‐chase situation due to a cell‐mediated conversion of thymidine to thymine in the medium. The uptake of thymine was slow compared to that of thymidine. Neither the addition of deoxyadenosine nor the sequential addition of several aliquots of [3H]thymidine had an effect on the pattern of labeling.
Seven New Eimeria spp. (Protozoa, Coccidia) from Freshwater Fishes of Canada*
Authors: MOLNAR KALMAN , HANEK GEORGE 
Published: May 2007

SYNOPSISSeven new species of Eimeria are described and figured from the freshwater fishes of Ontario and Quebec, Canada. They are Eimeria catostomi sp. n. and E. fernandoae sp. n. from Catostomus commersoni (Lacépède), E. etheostomae sp. n. from Etheostoma exile (Girard), E. hoffmani sp. n. from Umbra limi (Kirtland), E. micropteri sp. n. from Micropterus dolomieui Lacépède E. pungitii sp. n. from Pungitius pungitius (Linnaeus), and E. salvelini sp. n. from Salvelinus fontinalis (Mitchill). Furthermore, 2 new host records and 2 new distribution records for North America are reported for E. anguillae Léger & Hollande, 1922 and E. truttae Léger & Hesse, 1919 respectively. Finally, morphologically similar oocysts found in various cyprinids are regarded as belonging to E. iroquoina Molnar & Fernando, 1974.