bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the Motility of Plasmodium Sporozoites*
Authors: VANDERBERG JEROME P. 
Published: May 2007

SYNOPSISAlbumin was found to have a striking stimulatory effect on motility of Plasmodium sporozoites, while serum globulins had an inhibitory effect. Albumin also preserved viability of sporozoites in vitro at 4 C for several days. P. berghei, P. cynomolgi, and P. falciparum sporozoites each had a distinct and characteristic type of motility. P. berghei sporozoites from oocysts had a different type of motility from that of salivary gland sporozoites, each type presumably associated with different invasive capacities at different times during the life cycle of the parasite. This change in sporozoite motility during development was also associated with other physiologic developmental changes in the sporozoite. The degree of motility of a given pool of sporozoites was to some degree associated with other parameters of metabolic activity of these sporozoites, i.e. infectivity, immunogenicity, and secretory activity. Secretions of the rhoptry‐microneme complex may play a role in sporozoite motility.
Structure of Trichosphaerium micrum sp. n.
Authors: ANGELL ROBERT W. 
Published: May 2007

SYNOPSISTrichosphaerium micrumsp. n., a marine testate rhizopod, is described. It is ∼ 36 μ in diameter, covered with acicular, hollow, blunt‐ended calcite spicules, 1–3 μm in length, that lie flat in a fibrous sheath. The test is penetrated by circular semipermanent apertures through which extend short dactylopodia. Locomotion is by lobopodia which the organism uses to adhere to the substrate. It is multinucleate with an average of 9 nuclei/individual. The type locality is the shallow littoral of Big Pine Key, Florida.Spicules of other species are described and it is suggested that until more is known about the biology of the group, species classification in the order Trichosida be based on spicule structure and orientation, as well as the size of the organism.
Effect of Algal Exudates on Substratum Selection by Motile Telotrochs of the Marine Peritrich CiliateVorticella marina
Authors: LANGLOIS GAYTHA A. 
Published: May 2007

SYNOPSIS.Several species of marine peritrichs are found as epiphytes on small strands of filamentous green and red algae affixed to the substratum of marine intertidal rock pools. In pools located along the coast of Narragansett Bay, the motile vorticellid telotrochs appear to show a substratum selection for specific algae. Exudation products by marine algae have distinct differences; some Phaeophyta have particularly high values for dissolved organic matter (DOM), and for phenolic compounds. Algal exudates appear to influence population growth of vorticellids. The mean survival percentage of vorticellid populations increased with exposure to exudates fromCladophora gracilis, Polysiphonia harveyiandPolysiphonia lanosa; and decreased with exposure to those ofAscophyllum nodosum, Fucus spiralisandScytosiphon lomentaria.Telotroch settlement ofVorticella marinawas enhanced by exudates ofCladophora gracilis, Polysiphonia harveyiandPolysiphonia lanosa, but was reduced by exudates ofAscophyllum nodosum, and was prevented by exudates ofFucus spiralisandScytosiphon lomentaria.Algal exudates were obtained by allowing photosynthetic activity of the experimental algae for 6 hr. The exudates were filtered and the concentration of DOM, total phenols and carbohydrates determined. The filtered seawater containing the exudate was placed in a box‐type plastic dish on which the vorticellids had colonized. Survival percentages and the percentage of population due to telotroch settlement were calculated. This investigation indicates that algal exudates may exert a significant influence on the selection of substrata by vorticellid telotrochs and suggests that the ecologic stability of a given rock pool may be considerably lessened by a high level of Phaeophtya and the consequent reduction of Aufwuchs species.
Natural Variants of the Cellular Slime Mold Acrasis rosea
Authors: REINHARDT DONALD J. 
Published: May 2007

SYNOPSIS. Twenty different isolates of the cellular slime mold Acrasis rosea, obtained from diverse sources and geographic regions, were studied to determine similarities and differences in their development and structure in culture and their sensitivity or resistance to selected chemicals incorporated into the culture media. Six different classes of fruiting were defined based on the size, distribution, and type of sorocarps formed on the yeast, Rhodotorula, streaked on agar. In the course of these studies a significant mutant, NC‐18V (variant), developed spontaneously from the wild type, normal parent strain NC‐18N. The mutant differed considerably from all other Acrasis isolates, appeared several times in purified parental cultures, and represents the first laboratory derived variant of A. rosea to be described. Purified strains of the variant (V) and normal (N) cultures were obtained by single‐spore isolation. Normal and variant amebae were mixed in ratios of 10:1 and 100:1 (N:V) and spore and stalk cells were selected from different sorocarps in various regions of the culture plate for analysis. The results of these selection experiments clearly indicate that the individual variant amebae have increased migratory ability and that they develop smaller, morphologically different, and more numerous sorocarps that form at distances further from the food source than NC‐18N. Some isolates of Acrasis no longer were able to fruit and were classified as “non‐fruiters” and a few other isolates formed only a few, small sorocarps on rare occasions. These isolates were mixed together in various combinations of 2 and 3 to screen for cell interaction, but no synergism contributing to fruiting was found. Although fruiting of many A. rosea isolates was inhibited by exposure to continuous light or constant darkness, some “escape”fruiting was noted in certain isolates even when small inocula were used. Single spore isolates of these escape fruiters still fruited in continuous light or dark, but fruiting was always greatly enhanced by a routine 12 hr light : 12 hr dark incubation cycle. It was shown by biochemical studies that actidione, crystal violet, malachite green, ethyl violet, and 5‐fluorodeoxyuridine selectively killed some isolates and permitted a classification of isolates as either sensitive or resistant. In a further study of cell interaction between 2 different sets of Acrasis isolates with contrasting biochemical and morphologic markers the formation of neotypes or recombinants could not be demonstrated.The results of this study clearly indicate the existence of significant variation in A. rosea and the potential for application of these differences to developmental studies.
A Simplified Overlay Plaque Technic for Evaluating Responses of Small Free‐Living Amebae in Grassland Soils*
Authors: MENAPACE DIANA , KLEIN D. A. , MCCLELLAN J. F. , MAYEUX J. V. 
Published: May 2007

SYNOPSIS. The responses of amebae and bacteria in a grassland soil were investigated by an overlay plaque technic developed in this laboratory. This procedure, using Aerobacter aerogenes as the food source, allowed convenient assay of significant changes in ameba populations which resulted from additions of nutrient and water. In comparison with controls, when water was added an initial increase occurred in bacterial counts followed by an increase in the numbers of amebae. Upon addition of glucose, ameba populations increased initially and then decreased with time, while populations of bacteria remained constant. The addition of hay resulted in significant increases in populations of bacteria and amebae. Plaque appearance on enumeration plates was most rapid with inocula from nutrient‐treated soils.Predominant amebae recovered by this technic were species of Acanthamoeba and Hartmannella. They were estimated to be present in untreated soils at 3.2 × 103/gram. Ameba feeding experiments were used to evaluate the possible suitability of other bacteria as food. The results indicated that nonpigmented laboratory strains of bacteria were preferred, while pigmented grassland isolates were more rapidly utilized.Small soil amebae appear to be sensitive to minor soil perturbations, and the enumeration procedure developed in this study should aid in following their responses to environmental stresses.
Reduced Growth of Blastocrithidia culicis and Crithidia oncopelti Freed of Intracellular Symbiotes by Chloramphenicol*
Authors: CHANG K.‐P. 
Published: May 2007

SYNOPSISThe intracellular symbiotes of Blastocrithidia culicis and Crithidia oncopelti can be eliminated from cultures of the flagellates by a single chloramphenicol (CAP) treatment. Effective dosages were determined to be 0.01–0.08% (w/v) CAP after a treatment for 2 weeks or more for B. culicis and 0.08% (w/v) after 1 month for C. oncopelti in most cases. Ineffective dosages only lowered the numbers of symbiote‐bearing flagellates. Growth of both species of flagellates in the presence of CAP was reduced in proportion to the drug concentration. Repeated subcultures at effective dosages yielded symbiote‐free flagellates, which maintained a low level of growth rate. After repeated subcultures at ineffective dosages, the growth rate rose and the symbiote‐bearing cells, initially very few, increased in number. The lowest effective dosages proved to be marginal, often producing symbiote‐free cultures, but occasionally cultures with a few symbiote‐bearing cells. After repeated subcultures at these drug concentrations, symbiote‐containing cultures grew faster than the symbiote‐free cultures. Hence, the symbiotic bacteria benefit the growth of their hosts, perhaps by supplying essential factors that are inadequate even in a rich blood medium.
A Mathematical Model of Pattern Formation by Swimming Microorganisms*
Authors: LEVANDOWSKY M. , CHILDRESS W. S. , SPIEGEL E. A. , HUTNER S. H. 
Published: May 2007

SYNOPSISBioconvection in suspensions of Tetrahymena pyriformis and Crypthecodinium cohnii is described and 2 new patterns, the toroid and the cat's‐eye, which appear in shallow suspensions of C. cohnii, are reported. Except in very dense cultures, bioconvection does not arise unless the depth of the suspensions or the mean concentration exceed certain critical values, other things being equal. A mathematical model describing the hydrodynamics of suspension of negatively geotactic microorganisms is described which predicts the existence of critical depths and concentrations. The equations presented admit solutions describing the “polka‐dot” patterns seen at low organism concentration in suspensions slightly deeper than the critical value. The discussion here is limited to the case of fairly dilute suspensions, but the basic approach can be applied also to richer cultures.
Demonstration of Concanavalin A Receptors on Leptomonas pessoai Cell Membrane*§
Authors: DE SOUZA WANDERLEY , BUNN MARLENE M. , ANGLUSTER JAYME 
Published: May 2007

SYNOPSIS. Leptomonas pessoai promastigotes cultivated in a synthetic medium were agglutinated with concanavalin A (Con A). Agglutination was predominantly of the flagellar‐flagellar type, and was inhibited with sucrose or α‐methyl‐D‐mannoside.Cell surface polysaccharides and/or glycoproteins were demonstrated by several cytochemical methods at the fine‐structural level. A Con A‐horseradish peroxidase‐diaminobenzidine (DAB) technic was used to detect Con A receptors in the pellicular membrane of the flagellar pocket region and in the flagellar membrane proper. Somewhat less of the Con A‐DAB reaction product was observed in the pellicular membrane enclosing the rest of the cell.
La Réorganisation Infraciliaire au Cours de la Conjugaison et l'Origine du Primordium Buccal dans le Genre Euplotes
Authors: TUFFRAU MICHEL , TUFFRAU HELENE , GENERMONT JEAN 
Published: May 2007

RESUMEL'infraciliature ventrale est presque entièrement détruite lors de la conjugaison: la totalité des structures buccales, tous les cirres fronto‐ventraux et transversaux, certains cirres caudaux. Le retour à l'état végétatif s'effectue en 2 étapes.Première Etape.–Différenciation d'un nouvel ensemble de cirres, dépourvu du cirre 1/I (selon la nomenclature de Wallengren); néoformation, à partir d'une ébauche située sur le territoire présomptif du cirre manquant, d'une partie des structures buccales (la moitié antérieure de la frange adorale de membranelles).Deuxième Etape.–Remplacement de tous les cirres par un nouvel ensemble comportant le cirre 1/I; différenciation des structures buccales manquantes (moitié postérieure de la frange adorale, ciliature parorale)Les rapports morphogénétiques entre le cirre 1/I et la ciliature parorale suggèrent que le territoire de ce “cirre paroral” est homologue des territoires stomatogènes d'autres Hypotriches tels que Kahliella et Stylonychia.SYNOPSIS. During conjugation of Euplotes, the ventral ciliature, including the entire oral apparatus, all the fronto‐ventral and transverse cirri, and some of the caudal cirri, is nearly completely lost. As followed in silver‐stained preparations, the redifferentiation of the ciliature proceeds in 2 steps. The first step entails differentiation of a new complement of cirri, except for cirrus 1/I (according to the nomenclature of Wallengren), and neoformation of the anterior part of the adoral zone of membranelles (AZM) from a primordium located in an area that would be expected to give rise to the missing 1/I cirrus. The 2nd step involves replacement of all the cirri, including 1/I, and completion of the oral apparatus by redifferentiation of the posterior half of the AZM and of the paroral ciliature. The spatial morphogenetic relationships between cirrus 1/I and the paroral ciliature suggest that the area of this “paroral cirrus” is homologous with the stomatogenic areas of other Hypotrichida, such as Kahliella and Stylonychia.
RNA Synthesis in Division SynchronizedTetrahymena:Macronuclear and Cytoplasmic RNA*
Authors: HERMOLIN JOSEPH , ZIMMERMAN ARTHUR M. 
Published: May 2007

SYNOPSIS.Synthesis of RNA in the macronucleus and appearance of RNA in the cytoplasm were studied in heat synchronizedTetrahymena pyriformisGL and compared to those found under conditions of logarithmic growth (28 C) and during heat shocks (34 C).In macronuclei of logarithmically growing cells precursors were processed to 2 rRNA species (25S and 17S). In addition, another RNA (15S), more homogeneous than the RNA (8‐15S) in the cytoplasm, was observed in the macronucleus. Both 17S and 25S rRNA species were found in the cytoplasm, 17S rRNA appearing more rapidly than 25S rRNA. Synthesis of rRNA was suppressed at 34 C in cells subjected to heat synchronization; 8‐15S RNA synthesis appeared to be inhibited to a lesser extent.During the time preceding the first synchronized division, the synthesis of rRNAs in the macronucleus slowly recovered. Early in the cycle, almost no newly synthesized rRNAs were extracted. By 30 min after the last heat shock (EH), most of the RNA synthesized was not identified as rRNA. By 60 min after EH, the pattern of RNA synthesis had not returned to that observed in logarithmically growing cells.
Dinoflagellate Evolution: Speculation and Evidence*†
Authors: LOEBLICH ALFRED R. 
Published: May 2007

SYNOPSIS.Nuclear features of dinoflagellates that were used originally to support the Mesocaryota concept are reviewed. The fibrillar diameter of dinoflagellate chromatin, low level of chromosomal basic proteins, membrane attachment of chromosomes and swirl pattern observed in sectioned chromosomes are features that support a prokaryotic affinity. The presence of repeated and highly complex DNA, a S‐phase of DNA synthesis in the cell cycle, presence of basic proteins, and the reinterpretation of extranuclear microtubules as a spindle support the contention that dinoflagellates are eukaryotes. This combination of prokaryotic and eukaryotic features suggests that dinoflagellates are a geologically old group and that perhaps they diverged from the higher eukaryotic lineage before evolution of eukaryotic chromatin but after the evolution of repeated DNA. The 2 patterns of carotenoid composition exemplified by the presence of peridinin or fucoxanthin suggest separate origins of dinoflagellate plastids, perhaps by prokaryotic and eukaryotic capture. It is suggested that the species possessing fucoxanthin obtained their plastids by capture of photosynthetic eukaryotes.A new class and order, Syndiniophyceae and Syndiniales, are proposed for the dinoflagellates with low chromosome numbers, V‐shaped chromosomes, chromosomes containing a sufficient quantity of basic proteins detectable histochemically, possession of centrioles associated with mitosis, intracellular parasitism as a mode of nutrition, and lack of a cellular covering containing plates.Ultrastructural and paleontologic evidence indicates that the thecate is more primitive than the nonthecate condition.The Prorocentrales are considered to be primitive and their thecal construction is reinterpreted as having epithecal and hypothecal regions surrounding a flagellar pore region containing 7 plates. Acritarchs resemble cysts of modern dinoflagellates in size, structure, and chemical composition except for the absence of a polygonal excystment aperture and lack of any indication of transverse and longitudinal flagellar grooves on the acritarchs. The suggestion that some acritarchs may have dinoflagellate affinities is supported by the occurrence of modern dinoflagellates (Prorocentrales) which lack a theca of numerous polygonal plates and lack transverse and longitudinal flagellar arrangement. The Prorocentrales, as opposed to the more typical Dinophyceae, perhaps represent the type of organism that produced some acritarchs.
Laboratory and Field Studies on Glugea stephani (Hagenmuller), a Microsporidan Parasite of Pleuronectid Flatfishes*
Authors: OLSON ROBERT E. 
Published: May 2007

SYNOPSIS. The microsporidan Glugea stephani is a common parasite of juvenile English sole (Parophrys vetulus) in Yaquina Bay, Oregon. Field observations indicated that fish became infected only in the upper estuary where summer temperatures were above 15 C and the incidence of infection reached 79.8% in the late fall.Laboratory infections developed and parasite growth occurred only at or above 15 C. The parasite was successfully transmitted to juvenile English sole by brine shrimp (Artemia salina) and amphipod (Corophium spinicorne) vectors as well as by direct ingestion of spores by the host. Infections that resulted from ingestion of spore‐carrying vectors were much heavier than those resulting from the direct ingestion of spores. The speckled sanddab (Citharichthys stigmaeus), a nonpleuronectid flatfish, and chum salmon (Oncorhynchus keta) were refractory to G. stephani infection in the laboratory.Results of this study suggest that G. stephani is potentially lethal to young pleuronectid flatfishes when heavy infections involve the entire intestine and reduce the capacity to absorb nutrients. Under these circumstances, starvation is probably the direct or indirect cause of death. The restriction of infection to fish that reach the upper estuary very likely mitigates the impact of G. stephani caused mortality on the entire English sole population on the Yaquina Bay nursery ground.
Cytochemical Nature and Fine Structure of the Gregarine Zeylanocystis burti Dissanaike, with Special Reference to Microfilaments, Microtubules and Movement
Authors: SATHANANTHAN A. HENRY 
Published: May 2007

SYNOPSIS. The mature trophozoite of the acephaline gregarine Zeylanocystis burti Dissanaike, parasitic in the seminal vesicles of the Sri Lankan earthworm Pheretima peguana Rosa, was studied by cytochemical methods and by electron microscopy. Some observations were also made on gametocysts and oocysts.The trophozoite has a peculiar saucer shape, unlike other monocystid gregarines, and has marginal papillae with cytoplasmic hairs. Its fine structure conforms broadly to that of other gregarines, but differs with respect to its fibrillar organization and in some details of cytoplasmic organelle structure. The pellicle is composed of 2 parallel unit membranes elevated into a number of stumpy epicytary folds, more or less evenly distributed on both surfaces of the gregarine. Some of these are associated with adjacent accessory cells and may have a nutritive role. Bundles of fine microfilaments (5–6 nm) were detected both in the ectoplasm and deep in the endoplasm; these are possibly the main contractile elements (“myonemes”) involved in movement. Microtubules are larger (22–24 nm) and are found predominantly in papillae and cytoplasmic hairs, but extend also in small bundles beneath the pellicle—they appear to be more skeletal in nature. The significance of these findings is discussed in the light of recent work on the roles of microfilaments and microtubules in nonmuscle cells. Mitochondria are located superficially and have a complex organization. The endoplasmic reticulum is poorly developed, but ribosomes are abundant. Golgi lamellae‐like membranes and vesicles akin to lysosomes were observed. Typical paraglycogen granules were found together with blobs of lipid and glycogen. The nucleus had a wrinkled envelope, a homogeneous matrix, and a spherical nucleolus.A variety of staining reactions and cytochemical tests were carried out. The distribution of lipids, polysaccharides, nucleic acids, calcium, and melanin were studied. Succinate dehydrogenase was detected in mitochondria, thiamine pyrophosphatase in Golgi bodies, and acid phosphatase in lysosomes. Golgi structures were found to be chemically very complex.Gametocysts and oocysts were associated with extraneous cells which probably contribute to the formation of their walls. The gametocyst wall is thin and consists of 2 membranes of the unit type. The oocyst wall is thicker and composed of 2 chemically different layers. Telolysosomes were seen in the disorganized residual cytoplasm within gametocysts.
Ormieresia carcini gen. n., sp. n., Microsporidie du Crabe Méditerranéan, Carcinus mediterraneus Czerniavsky, 1884: Cycle Évolutif et Étude Ultrastructurale
Authors: VIVARES CHRISTIAN P. , BOUIX GEORGES , MANIER JEHANNE‐FRANÇOISE 
Published: May 2007

RÉSUMÉ. Une nouvelle microsporidie, Ormieresia carcini gen. n., sp. n., est trouvée dans Carcinus mediterraneus Czerniavsky, 1884. Son évolution et ses ultrastructures sont étudiees.Le cycle débute par un méronte limité par une membrane unitaire et possédant un diplocaryon. Toute la sporogonie se déroule dans la musculature de l'höte. Les stades sporogoniaux sont enveloppés dans une membrane pansporoblastique persistante. Dans chaque pansporoblaste, la sporoblastogenése (donnant naissance à 8 sporoblastes) est particulière; un plasmode sporogonial octonucléé manque. Au cours des divisions schizogoniques et sporogoniques, chaque centre cinétique est formé de 2 plaques, une incluse dans l'enveloppe nucléaire, l'autre occupant une position extranucléaire. Les sporontes en division et les sporoblastes sécrètent des substances métaboliques (granules, tubes) qui sont déposées dans l'espace pansporoblastique.La spore uninucléée est longue et cylindrique (19,1 × 2,4 μm). Un manubrium rectiligne traverse la spore. Son extrémité postérieure se rétrécit brusquement en un filament polaire décrlvant 4 ou 5 tours de spire. L'extrémité antérieure du manubrium est attachée au capuchon polaire lui‐même comprimé par un double anneau. La partie antérieure du manubrium est entourée par un polaroplaste formé d'une zone spongieuse et d'une zone lamellaire.