bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Fine Structure of the Colonial Colorless Flagellates Rhipidodendron splendidum Stein and Spongomonas uvella Stein with Special Reference to the Flagellar Apparatus
Authors: HIBBERD DAVID J. 
Published: May 2007

SYNOPSIS. The cell structure of the colorless colonial flagellates Rhipidodendron splendidum Stein and Spongomonas uvella Stein has been examined by electron microscopy to assertain their phylogenetic affinities. The cylindrical cells of R. splendidum have 2 smooth flagella of equal length, an asymmetrical flagellar pocket supported by microtubules, and a curved pit between the latter and an anterior prolongation of the cell. The matrix of the branched tubes comprising the fanshaped colony is composed largely of dense spherules which are produced in special cytoplasmic vesicles some of which contain symbiotic bacteria. The anterior nucleus has a flattened sac pressed closely against its posterior end. The sac has a long tail extending deep into the cytoplasm, a single bounding membrane and homogeneous contents. Several types of vesicle are described but food vacuoles and contractile vacuoles could not be positively identified. A kinetoplast mitochondrion is not present. The various cross‐banded, microtubular and amorphous components of the complex and highly asymmetrical flagellar root system are described in detail and a 3‐dimensional reconstruction is provided.The ovoid cells of S. uvella are basically similar to those of R. splendidum; though a nuclear sac is missing, there are some detailed differences in the structure of the flagellar root system, and bacteria are never present in the vesicles producing the matrix granules. Notwithstanding much similarity, Rhipidodendron is not combined with Spongomonas because of the basic difference in colony structure.The possible relationships of R. splendidum and S. uvella with other groups are examined and it is concluded that they cannot be considered as colorless chrysomonads as previously thought or considered to be related to any of the other orders comprising the class Phytomastigophorea. They do not, however, appear to be related to any of the orders at present comprising the Zoomastigophorea.
Feline Toxoplasmosis from Acutely Infected Mice and the Development of Toxoplasma Cysts*
Authors: DUBEY J. P. , FRENKEL J. K. 
Published: May 2007

SYNOPSIS. The development of Toxoplasma cysts was studied in mice inoculated with tachyzoites by several routes. After 1–30 days of infection, murine tissues were examined microscopically, and portions or whole carcasses were fed to mice and cats. The feces of the cats were examined for oocyst shedding.Cyst‐like structures containing distinct PAS‐positive granules were first seen after 3 days of infection with tachyzoites, and became numerous by 6 days. Argyrophilic walls were first seen after 6 days, and became numerous by 16 days of infection with tachyzoites.Prepatent periods to oocyst shedding (PPO) were either “short” (3–10 days) or “long” (19–48 days). The “short” PPO was found only in cats that had ingested mice infected for 3 days or longer, and was related to the development of PAS‐positive granules in T. gondii, and to high, 60–100%, oral infectivity rates for cats. The “long” PPO followed the ingestion of mice infected for only 1–2 days, and was related to tachyzoites without distinct PAS‐positive granules and low, 32% or less, infectivity for cats. The “long” PPO followed also the ingestion of oocysts and the parenteral inoculation of tachyzoites, bradyzoites, or sporozoites.Using the “short” PPO as a criterion for detecting cysts in tissues, it was shown that (a) numerous cysts developed in mice 5 days after inoculation with tachyzoites, 7–9 days after inoculation with cysts, and 9–10 days after inoculation with oocysts, and (b) cysts developed faster and more frequently in the brain and muscle than in lungs, liver, spleen, and kidneys of mice inoculated with tachyzoites.
Hydrolytic Enzymes of Euglena gracilis: Characterization and Activity as a Function of Culture Age and Carbon Deprivation*†
Authors: BAKER WILLIAM B. , BUETOW D. E. 
Published: May 2007

SYNOPSIS. Optimal assay conditions are described for 8 hydrolases of Euglena gracilis var. bacillaris, SM‐L1 (streptomycinbleached) strain, 7 of which have an acid pH‐optimum. Acid phosphatase, β‐galactosidase, β‐glucosidase, β‐fucosidase, cathepsin D, RNase, DNase, and an esterase are active in cell homogenates. Amylase has very low activity, and β‐glucuronidase, arylsulfatase, β, N‐acetyl‐glucosaminidase, α‐fucosidase, and α‐ and β‐mannosidase are inactive.Hydrolase activity increases as a culture proceeds from the midexponential to the late stationary‐phase of growth, being most pronounced in the case of β‐glucosidase. In cultures deprived of a utilizable carbon source, the specific activities of the hydrolases (per mg total protein or dry weight) increase. When expressed on a per cell basis, however, the activities of DNase decrease while those of β‐galactosidase, cathepsin D, and RNase increase. The hydrolases appear to be involved in the adaptation of Euglena to the metabolic demands imposed by different conditions of growth.
Phosphofructokinase of Leishmania donovani and Leishmania braziliensis and its Role in Glycolysis*
Authors: BERENS RANDOLPH L. , MARR J. JOSEPH 
Published: May 2007

SYNOPSIS. It was shown in an investigation of the phosphofructokinases of Leishmania donovani and Leishmania braziliensis that both enzymes are similar to that of Crithidia fasciculata. Although the enzymes are allosteric with respect to their substrates and require AMP for activation, there is no influence by other heterotropic modifiers. The Mg2+‐ATP chelate activates these enzymes in a first order process and they can be inhibited by free ATP. The inhibition is reversed by the activator, AMP, in a competitive manner. The requirement for the nucleotide in L. donovani can be eliminated by decreasing the pH.The data indicate that phosphofructokinase, a pivotal enzyme in glycolysis for most organisms, probably does not play an important role in glycolysis in Leishmania.
The Nutrition of the Freshwater Dinoflagellate Ceratium hirundinella*
Authors: BRUNO STEPHEN F. , MCLAUGHLIN JOHN J. A. 
Published: May 2007

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

SYNOPSIS. Examination of littoral fish Blennius pholis and Cottus bubalis caught at Aberystwyth and Porth Cwyfan, Wales. U.K., revealed 2 species of coccidia.Eimeria dingleyi sp. n. Oocysts spherical (16.1–19.2) to subspherical (13.9–14.2 × 18.8–20.0) μm, with thin walls; sporulation outside the host to produce ellipsoid sporocysts; endogenous phases in epithelial cells throughout intestine; 26 of 58 B. pholis infected.Eimeria variabilis (Thélohan) Reichenow. Oocysts spherical (11.9–14.6) to subspherical (9.2–10.9 × 13.9–14.3) μm; sporulation in lining of pyloric ceca and rectum; previously unrecorded schizonts and gametocytes present; 21 of 25 C. bubalis infected.Electron microscopy revealed that the oocyst wall of E. variabilis consists of a thin membrane whereas the sporocyst wall is thick and 3‐layered. Typical oocyst wall‐forming bodies were absent from the macrogamete. Cytochemical tests on the endogenous stages of E. dingleyi and E. variabilis indicated that in general they resembled other coccidia in their chemical constitution.
Fine Structure of the Neogregarine Farinocystis tribolii Weiser, 1953. Developmental Stages in Merogony.
Authors: ŽIŽKA ZDENĚK 
Published: May 2007

SYNOPSIS. The fine structure of schizonts and free merozoites of the neogregarine Farinocystis tribolii Weiser, and their development in the fat body of larval Tribolium castaneum were studied.The surface of a multinucleate schizont and that of a uninucleate merozoite is covered by a double‐layered membrane. Rhoptries and micronemes are present. The cytoplasm is packed with ribosomes and also contains dark bodies. Mitochondria are of the vesicular type. The spherical nucleus of the schizont and merozoite contains a large nucleolus. The anterior end of the merozoite has a typical conoidal complex composed of a conoid and a polar ring with 22 subpellicular mirotubules projecting from it.New findings are a membranous septum across the body of the merozoite at 2/3 of its length below the nucleus and a highly osmiophilic spiral structure in the perinuclear space close to the Golgi complex. In addition, we found some “developmental stages” of the latter structure.
Preuves Cinétiques de l'Existence d'une Période de Compétence pour la Transformation Microstome‐Macrostome dans le Cycle Cellulaire de Tetrahymena paravorax
Authors: METENIER GUY 
Published: May 2007

RÉSUMÉ. Des expérimentations portant sur des cellules isolées ont montré que 77% des microstomes de Tetrahymena paravorax, prélevés au hasard dans des cultures en phase logarithmique de croissance, se transforment directement en macrostomes en présence de “stomatine.” Ces macrostomes apparaissent à des moments variés entre 1,5 et 9 h après l'addition de la stomatine (“point 50% de transformations” vers 2,5 h). La compétence pour le remplacement oral est en relation avec la position dans le cycle cellulaire. Les pourcentages de transformation les plus élevés sont observés avec les populations testées pendant la première moitié de la période moyenne d'interfission. La formation des macrostomes est d'autant plus rapide que l'ǎge initial des microstomes est plus proche du point médian du cycle cellulaire (“point de compétence”). Dans la seconde moitié de ce cycle, le temps moyen de transformation reste à peu près constant, mais le pourcentage de divisions augmente: le “point de transition” (50% de divisions) se trouve au début d'une phase terminale représentant 19–20% de la durée totale du cycle. La transformation des produits de bipartition antérieur et postérieur est nettement asynchrone: dans la majorité des paires cellulaires, l'opisthe se transforme avant le proter. Les cellules‐soeurs se divisent aussi de manière asynchrone: le temps de génération du proter est plus long que celui de l'opisthe.Le problème de l'acquisition de la compétence pour le changement de phénotype est discuté en envisageant les corrélations éventuelles avec certains processus majeurs du cycle cellulaire.SYNOPSIS. Seventy‐seven percent of the microstomes of Tetrahymena paravorax taken from random samples of log‐phase cultures transform directly into macrostomes in the presence of “stomatin.” These macrostomes appear between 1.5 and 9 h after addition of stomatin (“50% transformation point,”∼ 2.5 h). Competence for oral replacement is related to the position in the cell cycle. The highest percentages of transformation are observed in populations tested during the first half of the mean interfission period. Formation of macrostomes is more rapid when the initial age of the microstomes is nearer to the midpoint of the cell cycle (“competence point”). In the 2nd half of this cycle, the mean transformation time remains approximately constant, but the percentage of cells undergoing division is increasing. The “transition point” (50% divided cells) is found at the beginning of a terminal phase which accounts for 19–20% of the cell cycle. Transformation of anterior and posterior fission products is fairly asynchronous; in the majority of individual pairs, the opisthe is transformed before the proter. The daughter cells also divide asynchronously, the generation time of the proter being longer than that of the opisthe. The problem of acquisition of competence for phenotypic change is discussed in light of possible correlations with certain major processes of the cell cycle.
Alteration of the Tetrahymena Genome During Nuclear Differentiation*†
Authors: YAO MENG‐CHAO , GALL JOSEPH G. 
Published: May 2007

Synopsis.The DNA of the macro‐ and the micronucleus of Tetrahymena thermophila has been compared by various biochemical methods. It became evident from their thermal denaturation temperatures and buoyant densities that the 2 DNAs were very similar in overall composition. Small differences were detected when the sequence complexities of these DNAs were compared by DNA renaturation studies. The studies suggested that ˜ 10% of the micronuclear genome was lost or underrepresented in the macronucleus. Comparison of individual gene levels revealed further differences. By using the technic of gene cloning a micronuclear sequence was isolated which hybridized only with micronuclear, but not with macronuclear DNA. These results indicated the occurrence of elimination or underreplication of this sequence in the macronucleus. Gene amplification was also shown to occur. In the micronucleus only a single copy of rDNA was found integrated into the chromosome. During macro‐nuclear development, amplification was observed to occur, and the amount of rDNA to increase, until there were ˜ 200 copies per haploid genome in the mature macronucleus. all of them extrachromosomal and palindromic. The 3rd case of alteration involved a simple repeated sequence, (CCCCAA)n, present in the termini of rDNA and also in many other locations of the genome. Restriction endonuclease digestion studies revealed drastic differences in the organization of the repeats between macro‐and micronucleus. These differences may be interpreted as the results of chromosome fragmentation which occurs at every cluster of the repeats during macronuclear development. The relationship between this event and gene amplification and elimination is discussed.
Facieplatycauda pratti gen. n., sp. n. and Two New Species of Myxobolus (Myxosporida)*
Authors: WYATT ELLIS J. 
Published: May 2007

Synopsis.Facieplatycauda pratti gen. n., sp. n. and Myxobolus kozloffi sp. n., from the Klamath Lake sucker,Catostomus luxatus (Cope), are described. The new genus is placed in the family Myxobolidae between Henneguya and Myxobolus. The spore valves beyond the sporoplasmic space are broad and long but not attenuated as an inverted triangle as in certain species of Myxobolus with tails, or of Henneguya with sometimes bifurcated tails. An organism resembling Myxobolus insidiosus (Wyatt & Pratt) was found in the muscle of the body of Salmo clarki (Richardson). Differences in spore structure and site of infection suggest this is a subspecies of the previous form which should be designated Myxobolus insidiosus clarki. A previously unreported species of Myxobolus from Cottus aleuticus (Gilbert) is also described.
Evidence for Chromosomal Macronuclear Substructures in Tetrahymena*†
Authors: SEYFERT HANS‐MARTIN 
Published: May 2007

SYNOPSIS.Under the growth conditions employed, the G1 macronucleus of Tetrahymena pyriformis HSM contains 7.4 × 10‐12 g DNA, the G2 micronucleus 0.42 × 10‐12 g. DNA content from the Tetrahymena thermophila macronucleus did not significantly differ from that of HSM, but the micronucleus contained about twice as much DNA as the micronucleus of the HSM cells. The T. thermophila macronucleus contained on average enough DNA for ˜ 35 haploid micronuclear copies. A new spreading technic allowed separation of macronuclear substructures from cells of late G2 to early G1. Photometric determination of DNA content of 345 individual structures suggested the existence of 5 different‐sized macronuclear structures with a DNA content corresponding to 2, 4, 8, and 16 × the basic values. Comparison of the DNA content of these structures with (a) mitotic micronuclear chromosomes and (b) meiotic micronuclear chromosomes of T. thermophila cells suggests that the 5 basic values of macronuclear structures derive from structures of micronuclear chromosomes. The micronuclear chromosomes of T. pyriformis may be oligotenic. It is suggested that these results further our understanding of macronuclear organization.
Morphologie, Infraciliatur und Ökologie der limnischen Tintinnina: Tintinnidium fluviatile Stein, Tintinnidium pusillum Entz, Tintinnopsis cylindrata Daday und Codonella cratera (Leidy) (Ciliophora, Polyhymenophora)*
Authors: FOISSNER WILHELM , WILBERT NORBERT 
Published: May 2007

Synopsis.Structure, infraciliature, and ecology of 4 fresh‐water Tintinnina were investigated. The lorica of Tintinnidium fluviatile is gelatinous, fragile, and contains some agglutinated material mainly of biologic origin. Its infraciliature consists of ˜ 10 kineties. with kinetosomes arranged in pairs. Only one basal body of a pair is ciliated, except for the uppermost 1–4 pairs which have 2 slightly elongated cilia. In Tintinnidium fluviatile. Tintinnidium pusillum, and Tintinnopsis cylindrata there are 2 prominent ventral organelles. The lorica of T. pusillum is gelatinous and coated with much agglutinated material of biologic and nonbiologic origin. Its infraciliature is similar to that of T. fluviatile, but the uppermost pair of kinetosomes has elongated cilia. The firm loricae of T. cylindrata and Codonella cratera are, built mainly of sharp‐cornered structures. The infraciliature of T. cylindrata is composed of ˜ 10 kineties with kinetosomes not arranged in pairs. The infraciliature of C. cratera consists of ˜ 32 kineties, in some of which the kinetosomes are paired, e.g. ventral kinety, and in others not paired, e.g. cilia of the very prominent lateral field and of the other somatic kineties. The uppermost kinetosomes of each somatic kinety are paired and have elongated cilia. In addition, there is an unusual ventro‐lateral kinety. The oral apparatus consists of adoral membranelles and a paroral membrane. The membranelles that enter the praecral cavity are very elongate, a feature perhaps unique to Polyhymenophora. The fibrillar system consists of a prominent praeoral ring formed by fibrils extending from the adoral membranelles. A finely meshed silverline system extends over the entire cell.A review of the ecology of the fresh‐water Tintinnina indicated that water temperature seems to be the most essential ecologic factor.The systematic position of the Tintinnina is discussed in light of their infraciliature. It is concluded that these organisms are most closely related to Oligotrichina, and probably to Heterotrichina.
Toxoplasma gondii‐Vertebrate Cell Interactions. II. The Intracellular Reproductive Phase
Authors: DVORAK JAMES A. , HOWE CHRISTINE L. 
Published: May 2007

SYNOPSIS.The reproduction of Toxoplasma gondii RH‐strain in vertebrate cells was studied in a controlled‐environment culture system. The lag period before reproduction and the doubling time of individual parasites were determined using a least‐squares linear regression method of analysis which does not artificially constrain the data. In the majority of cases, the time intercept of the linear regression line was either zero, implying the lack of a lag phase before reproduction, or negative, implying the parasite had completed part of its reproductive cycle before entering the host cell. The mean doubling time of T. gondii is 10.9 h in bovine embryo skeletal muscle cells and 8.3 h in HeLa cells. This difference is not significant at the 5% level. The population doubling times of mouse‐derived parasites is best described by a gamma distribution.
Rhabdospora thelohani Laguessé, 1895 (Apicomplexa): New Host and Geographic Records with Taxonomic Considerations*
Authors: MAYBERRY LILLIAN F. , MARCHIONDO ALAN A. , UBELAKER JOHN E. , KAZIĆ DANILO 
Published: May 2007

SYNOPSISNew fish species and geographic records for Rhabdospora thelohani Laguessé, 1895 (rodlet cells) are presented. Additionally, the ultrastructure of R. thelohani in Alburnoides bipunctatus ohridanus Karaman, Borostomias antarcticus (Louml;nnberg), Leuciscus cephalus albus Bonaparte and Rutilus rubilio (Bonaparte) is compared with that reported by other authors and with members of Subphylum Apicomplexa. The ultrastructure of R. thelohani was similar in all the fish species examined: however, the organism was not present in all members of any single species and had intertissue density variations. Rhabdospora thelohani is pyriform. averaging in size 7 × 12 m̈, with a basal nucleus. The surface complex is composed of a layer (0.5 m̈m diameter) formed by microfilaments (9.3 nm) and an outer trilaminar membrane (9.3 nm). The cytoplasm contains structures identical to rhoptries, micronemes and subpellicular microtubules. Mitochondria. Golgi apparatus, and rough endoplasmic reticulum were not observed, although free ribosomes were present and arranged in a vesicular pattern. The observations suggest that the organism moves between cells of epithelial layers and is either released into a lumen intact or passively or actively discharges its contents into a lumen. Results from this study indicate that R. thelohani should be considered a member of Apicomplexa unless definitive evidence is presented to the contrary.
Henneguya adiposa Minchew (Myxosporida) in the Channel Catfish: Ultrastructure of the Plasmodium Wall and Sporogenesis*
Authors: CURRENT WILLIAM L. 
Published: May 2007

SYNOPSISWall ultrastructure and sporogenesis were studied in plasmodia of Henneguya adiposa Minchew which infects the channel catfish, Ictalurus punctatus (Rafinesque). Plasmodia were located among connective tissue bands of the adipose fin and were always separated from host fibrocytes by collagen fibers. The plasmodium wall consisted of a single unit membrane which was continuous with numerous pinocytic canals extending into the parasite's ectoplasm. The membrane was highly convoluted, producing an irregular parasite surface, and was covered by a fine granular coat of almost uniform thickness. Early sporogenic stages were located in a zone of cytoplasm rich in mitochondria, just interior to the zone of pinocytic canals. Later sporogenic stages, including mature spores, were concentrated in the center of the plasmodia. Sporogenesis began with the envelopment of one generative cell, the sporont, by a 2nd, nondividing, cell—the enveloping cell. The sporont and its progeny proceeded through a series of divisions until 10 cells were present within the enveloping cell. Once divisions were completed, the 10 cells became arranged into 2 identical spore‐producing units, each consisting of one binucleate sporoplasm and 2 capsulogenic cells, all surrounded by 2 valvogenic cells. Later stages of spore development indicated that capsulogenesis, valvogenesis and sporoplasm maturation occurred concomitantly.