bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Bile Salt‐Stimulated Lipase‐Treated Triglycerides and Free Fatty Acids on Extracellular Stages of Eimeria tenella
Authors: WINTERROWD C. A. , FOLZ S. D. , HEINRIKSON R. L. , GEARY T. G. 
Published: May 2007

ABSTRACTNormal human milk (NHM) has antiprotozoal activity unrelated to immunological components; this activity extends to sporozoites of Eimeria tenella. This activity may be due to free fatty acids (FFA) enzymatically hydrolyzed from tnacyl glycerols by a bile salt‐stimulated lipase (BSSL) found in NHM. Sporozoites were therefore incubated in the presence of several saturated and unsaturated FFA. Anticoccidial activity was observed for many unsaturated fatty acids and for some saturated fatty acids. In addition, sporozoites were added to solutions of triglycerides (trilinolein, triolein and trilinolenin) preincubated with BSSL and sodium cholate. which resulted in killing of the parasites. Triglycerides alone showed no anticoccidial activity. These results were duplicated with first generation merozoites. Intracellular stages of E. tenella were affected by FFA only at concentrations that inhibited host cells.
Large Genetic Heterogeneity Within Amoebas of the Species Naegleria gruberi and Evolutionary Affinities to the Other Species of the Genus
Authors: PERNIN PIERRE , CARIOU MARIE LOUISE 
Published: May 2007

ABSTRACTThe allozyme survey was extended to 7 strains of Naegleria gruberi and N. jadini in order to further characterize the genetic structure of these free‐living amoebas. As formerly known for several characters the electrophoretic evidence reveals considerable heterogeneity at the genetic level among N. gruberi strains. Moreover, 2 distinct gene pools, that might likely represent natural taxa, are clearly identified. The single strain of N. jadini appears evolutionarily related to 1 group of N. gruberi which is also related to N. a. australiensis.
Biochemistry and Metabolism of Giardia
Authors: JARROLL EDWARD L. , MANNING PAUL , BERRADA ABDELKRIM , HARE DAWN , LINDMARK DONALD G. 
Published: May 2007

ABSTRACTGiardia lamblia, an aerotolerant anaerobe, respires in the presence of oxygen by a flavin, iron‐sulfur protein‐mediated electron transport system. Glucose appears to be the only sugar catabolized by the Embden‐Meyerhof‐Pamas and hexose monophosphate pathways, and energy is produced by substrate level phosphorylation. Substrates are incompletely oxidized to CO2, ethanol and acetate by nonsedimentable enzymes.The lack of incorporation of inosine, hypoxanthine, xanthine, formate or glycine into nucleotides indicates an absence of de novo purine synthesis. Only adenine, adenosine, guanine and guanosine are salvaged, and no interconversion of these purines was detected. Salvage of these purines and their nucleosides is accomplished by adenine phosphoribosyltransferase, adenosine hydrolase, guanosine phosphonbosyltransferase and guanine hydrolase.The absence of de novo pyrimidine synthesis was confirmed by the lack of incorporation of bicarbonate, orotate and aspartate into nucleotides, and by the lack of detectable levels of the enzymes of de novo pyrimidine synthesis. Salvage appears to be accomplished by the action of uracil phosphoribosyltransferase, uridine hydrolase, uridine phosphotransferase, cytidine deaminase, cytidine hydrolase, cytosine phosphoribosyltransferase and thymidine phosphotransferase. Nucleotides of uracil may be converted to nucleotides of cytosine by cytidine triphosphate synthetase, but thymidylate synthetase and dihydrofolate reductase activities were not detected.Uptake of pyrmidine nucleosides, and perhaps pyrimidines, appears to be accomplished by carrier‐mediated transport, and the common site for uptake of uridine and cytidine is distinct from the site for thymidine. Thymine does not appear to be incorporated into nucleotide pools.Giardia trophozoites appear to rely on preformed lipids rather than synthesizing them de novo. Major lipids include phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, sphingomyelin, sterol (probably cholesterol) and mono‐, di‐ and triacylglycer‐ides. The lipid composition of the cysts of G. lamblia isolated from gerbils and G. muris isolated from mice are similar to those obtained from the trophozoites of G. lamblia grown in vitro.The activities of several hydrolases of G. lamblia have been shown to be confined to a single lysosome‐like particle population with an equilibrium density of approximately 1.15 in sucrose. Contrary to the trophozoites of Entamoeba and the trichomonads, Giardia trophozoites appear to lack most carbohydrate splitting hydrolases.Calmodulin has been reported in G. lamblia trophozoites, and it appears to have properties similar to the calmodulin isolated from other eucaryotic cells.
Ornithine Decarboxylase and Trypanothione Reductase Genes in Leishmania braziliensis guyanensis
Authors: KEITHLY JANET S. 
Published: May 2007

ABSTRACT. Ornithine decarboxylase and trypanothione reductase are the key enzymes in polyamine and trypanothione metabolism in kinetoplastids. Using a heterologous Trypanosoma brucei brucei probe for ornithine decarboxylase and a mixed synthetic probe of 29 oligonucleotides for trypanothione reductase, we have detected the putative genes for these enzymes by Southern blot hybridization using genomic DNA of Leishmania braziliensis guyanensis MHOM/SR/80/CUMC I. The trypanothione reductase probe was constructed both from the conserved codon usage of the redox active site for other flavin oxidoreductases over a wide evolutionary scale, and the preferred codon usage for other genes in species of Leishmania.
I. Extracellular Cultivation and Morphological Characterization of Amastigote‐Like Forms of Leishmania panamensis and L. braziliensis
Authors: EPERON SIMONE , McMAHON‐PRATT DIANE 
Published: May 2007

ABSTRACT. Two strains of the Leishmania braziliensis complex have been adapted to grow extracellularly at elevated temperature as amastigote‐like forms in a cell‐free medium. These parasites can be serially cultivated and maintained at 32°C for L. panamensis (WR442; L. braziliensis panamensis) and at 28°C for L. braziliensis (M5052; L. braziliensis braziliensis). Several observations are presented that the forms adapted at elevated temperature are amastigote‐like. Morphologically, the amastigote‐like organisms appear rounded to ovoid and are immotile and smaller than promastigotes; the flagellum of the amastigote‐like forms does not extend beyond the flagellar pocket. In comparison, the promastigotes are very elongated, with a nucleus at mid‐cell length and a very long flagellum. By electron microscopy, the short flagellum of the amastigote‐like form is within a distended flagellar pocket; the 9 + 2 axonemal configuration is present but the paraxial rod is not observed. By contrast, the flagellum of the promastigote has a paraxial rod which extends from the axosome level. In addition, these amastigote‐like forms of Leishmania are able to infect, to survive and to divide within the macrophage cell line J774.
Extracellular Amastigote‐Like Forms of Leishmania panamensis and L. braziliensis. II. Stage‐ and Species‐Specific Monoclonal Antibodies
Authors: EPERON SIMONE , McMAHON‐PRATT DIANE 
Published: May 2007

ABSTRACTImmunochemical evidence, employing monoclonal antibodies, shows that the forms of L. braziliensis complex axenically grown at elevated temperature are amastigote‐like. The monoclonal antibodies were raised against membrane proteins of amastigote‐like forms, strains of both L. panamensis (WR442) and L. braziliensis (M5052), which were grown axenically. The specificities of these antibodies were examined by indirect radioimmune binding assay, indirect immunofluorescent assay and Western blot analyses. Two distinct groups of monoclonal antibodies were obtained and their specificities were consistent with the 3 methods used. Four antibodies are specific for the species L. panamensis and react with both developmental stages. Six antibodies specifically recognize amastigote‐like forms grown at elevated temperature and intracellular amastigotes of both L. panamensis (WR442) and L. braziliensis (M5052). These monoclonal antibodies do not bind to promastigotes of these species, nor to promastigotes of any other species of Leishmania. Therefore these antibodies are specific for amastigotes of L. panamensis (WR442) and L. braziliensis (M5052), and suggest that immunochemically both amastigote forms (culture and macrophage) are developmentally very close, if not identical. The molecules associated with the amastigote‐specific antigenic determinants consist of a Mr 12‐kD component and a heterogeneous component (Mr from 50 kD to >200 kD); these molecules appear to be identical for both amastigote‐like forms and amastigotes isolated from macrophages.
Mating Structure Differences Demonstrated by Freeze‐Fracture Analysis of Fusion‐Defective Chlamydomonas Gametes
Authors: FOREST CHARLENE L. , OJAKIAN GEORGE K. 
Published: May 2007

ABSTRACTWhile the mating structure of unmated mating type minus (mt‐) gametes of Chlamydomonas reinhardtii has few intramembrane particles (IMPs), activation results in movement of IMPs to its center. Analysis of freeze‐fractured replicas of wild type (wt) mt‐ and 3 mt‐ fusion‐defective mutants, gam‐1, gam‐10 and gam‐11, before and after activation with wt+ flagella, provides a basis for suggesting that some of the IMPs in mt‐ mating structures, particularly a subset of particles that partitions to the E face, may be fusion‐controlling molecules. Unmated gametes of gam‐10 show a full range of images, from particle‐free to fully activated, with both the P and E face of the mating structure revealing approximately twice as many IMPs as those observed on wt. Unactivated gametes of gam‐1 and gam‐11 appear identical to wt‐. After activation, the mating structures of all of these gametes appear to have approximately the same number of IMPs. If the sizes of particles for these mutants are compared to wild type at the restrictive temperature, all 3 mutants have significantly smaller IMPs on the E face; before mating, in the plasma membrane and after mating, in the mating structure. At 34° C, the gam‐1‐II mating structure appears to be missing most of the particles from 15.5 to 16.5 nm in diameter, while all gametes with the ability to fuse have an equivalent percentage of their mating structure particles in this size range. The possibility that an IMP in this size range represents a protein that may be responsible for gamete fusion is discussed.
Characterization of a Cytochalasin D‐Resistant Mutant of Entamoeba histolytica
Authors: GARZA MIREYA DE LA , GALLEGOS BRIGIDO , MEZA ISAURA 
Published: May 2007

ABSTRACTCharacterization of a cytochalasin D‐resistant mutant of the human parasite Entamoeba histolytica capable of growing at 10 μM cytochalasin is described. The mutant cells also show resistance to 5 mM colchicine and 100 μM cytochalasin B, drugs proved deleterious for wild type trophozoites. The mutants show increased osmotic fragility and electric mobility but reduced phagocytic activity, and agglutination by Concanavalin A. On the other hand pinocytic activity remains unaltered when compared with the wild type cells. Polymerized actin, seen by staining with phalloidin, often appears polarized to one end of the trophozoites and forms few of the endocytic invaginations found in wild type amebas. An altered distribution of part of the actin could explain the differences in surface properties and motility observed in the mutant amebas.
Redescription of Lagenophrys eupagurus Kellicott (Ciliophora, Peritricha, Lagenophryidae) and a Comparison of It with Three Similar Species
Authors: CLAMP JOHN C. 
Published: May 2007

ABSTRACTLagenophrys eupagurus, a poorly known loricate peritrich ectocommensal on the hermit crab Pagurus longicarpus, has been rediscovered and is redescribed. Lagenophrys lunatus and L. articularis were found to be conspecific with L. eupagurus based on close similarities, especially with regard to structure of the lorica aperture and proportions of the lorica. Lagenophrys callinectes, although resembling L. eupagurus, was determined to be a separate species because of distinct, consistent differences in structure of the lorica aperture and proportions of the lorica. Lagenophrys eupagurus and L. callinectes share some features of the lorica aperture with 3 other species of Lagenophrys, prompting the speculation that the 5 species may constitute a cluster of related species within the genus. Lagenophrys eupagurus utilizes a relatively wide variety of hosts compared to other species of Lagenophrys and appears to subsist mainly on phytoplankton. In some cases, the feeding behavior of the host may assist L. eupagurus in obtaining food. Lagenophrys callinectes appears to be restricted to brachyuran crabs of the genus Callinectes. It appears to be a bacterivore and is probably assisted in obtaining food by the preference of its hosts for estuarine areas that are rich in organic material.
Changes in Orthophosphate, Pyrophosphate and Long‐Chain Polyphosphate Levels in Leishmania major Promastigotes Incubated With and Without Glucose
Authors: BLUM J. J. 
Published: May 2007

ABSTRACTThe intracellular levels of orthophosphate (P1), pyrophosphate (PP1) and short‐ and long‐chain polyphosphate (Poly P) were measured in Leishmania major promastigotes incubated in a phosphate‐free medium. In the absence of exogenous substrate, the levels of both P1 and PP1 increased during a 1 h incubation. The increase in both P1 and PP1 was prevented when glucose was present, but glycerol prevented the rise in P1 only. A rise in P1 and PP1 was also seen in cells incubated in the absence of exogenous substrate under anaerobic conditions. This was reversed upon addition of glucose plus oxygen. Polyphosphate, here shown to be present in L. major, was measured by means of a polyphosphate glucokinase assay. Short‐chain Poly P content did not differ between cells incubated for 1 h in the absence of exogenous substrate or in the presence of glucose or glycerol. Long‐chain Poly P content, however, was lower in cells incubated without glucose than in cells incubated with glucose and was also lower in cells incubated for 1 h with glycerol as compared with freshly washed cells. Up to 61% of the increase in P1 and PP1 that occurred in promastigotes incubated in the absence of exogenous substrate could have arisen from the concomitant decrease in long‐chain Poly P.
Ultrastructural Observations on the Gametocytic Stages of the Coccidium Tyzzeria chalcides Probert, Roberts & Wilson, 1988 from the Ocellated Skink Chalcides ocellatus
Authors: DASZAK P. , PROBERT A. J. , RUNHAM N. W. , WILSON I. B. 
Published: May 2007

ABSTRACTGametogenesis of Tyzzeria chalcides Probert, Roberts & Wilson, 1988, from the ocellated skink, Chalcides ocellatus, occurs within the epithelium of the gali bladder. Transmission electron microscopy reveals that macrogamonts contain 2 types of wall‐forming bodies. Type I bodies are large densely stained structures associated with rough endoplasmic reticulum and the Golgi apparatus. They appear to be formed within the Golgi itself. Type II bodies are less densely stained, smaller and appear to form directly from the rough endoplasmic reticulum. Canaliculi are associated with Type I wall‐forming bodies and probably function to transport the wall‐forming bodies to the pellicle. Micropores occur in the pellicie and large amylopectin granules, lipid globules and dense bodies are found within the cytoplasm of the macrogamont. Mature microgamonts contain in excess of 20 microgametes, each of which has 2 flagella and an associated mitochondrion. Both types of gamont are found within a parasitophorous vacuole, in the host cell, which is filled with vesicular material on which the gamonts probably feed.
Vairimorpha necatrix in Adipose Cells of Trichoplusia ni
Authors: DARWISH AZIZA , WEIDNER EARL , FUXA JAMES R. 
Published: May 2007

ABSTRACTVairimorpha necatrix infected adipose ceiis of the fat body organ of Trichoplusia ni larvae 3–31/2 days after exposure of the larvae to infective spores. During the subsequent 4–6 days, the parasitized adipose cells were hypertrophied in part due to the rapid propagation of V. necatrix schizonts. A calcium‐sensitive tubule network developed at the interface of the schizonts and the adipose ceil cytoplasm. The paired nuclei of V. necatrix have pores at the nuclear interface. The pores for each nucleus at this interface are spatially positioned so that they are in conjunction; hence, there is the potential for a channel system between the 2 nuclei.
Ultrastructural Observations on Life Cycle Stages of Pneumocystis carinii
Authors: RUFFOLO JOHN J. , CUSHION MELANIE T. , WALZER PETER D. 
Published: May 2007

ABSTRACTAn ultrastructural study of life cycle stages of Pneumocystis carinii in infected rat lungs in situ was undertaken utilizing 8 different modes of fixation. Three of the fixatives employed gave good fixation of cysts and intracystic bodies, but for the trophic forms fixation was only fair. Both the trophic forms and intracystic bodies have nuclear pores. The mitochondria of the organism have cristac that appear lamellar. One of the fixation modes revealed a thin, electron‐dense layer on the outer surface of the cell wall, a “fuzzy coat” that had not been described previously. This material appears to mediate tight adhesion of trophic forms with other trophic forms, cysts, and with pneumocytes of the lung alveolus.
Surface Labeling of Pneumocystis carinii from in Vitro Culture
Authors: RADDING JEFFREY A. , ARMSTRONG MARTINE Y. K. , BOGUCKI M. SANDRA , RICHARDS FRANK F. 
Published: May 2007

SUMMARY.Pneumocystis carinii is an opportunistic pathogen of man, carried as a commensal in healthy subjects. It frequently causes a fatal pneumonia in the immunosuppressed host. It is a major complication of HIV‐1 infection in man (AIDS). Using surface radioiodination of rat‐derived P. carinii trophozoites obtained from in vitro culture, a major surface glycoprotein (gpl20) has been identified. The glycoprotein exhibits adherent behavior similar to that of the intact organism. Purification of gpl20 by conventional methods was unsuccessful as the glycoprotein irreversibly bound to numerous column matrices. A combination of gel chromatography and hydroxyapatile chromatography in sodium dodecylsulfate was utilized to purify the glycoprotein. Some preliminary characterization of the glycoprotein is presented.
The Interaction of Naegleria fowleri Amoebae with Murine Macrophage Cell Lines
Authors: FISCHER‐STENGER KRISTA , CABRAL GUY A. , MARCIANO‐CABRAL FRANCINE 
Published: May 2007

ABSTRACTThe present study was undertaken to determine whether murine macrophage cell lines exhibited in vitro amoebicidal activity comparable to that elicited by activated murine peritoneal macrophages. Peritoneal macrophages activated in vivo by bacillus Calmette‐Guérin or Propionibacterium acnes demonstrated significant cytolysis of Naegleria fowleri amoebae. The macrophage cell line RAW264.7 also effected cytolysis of amoebae, but to a lesser extent than that elicited by activated peritoneal macrophages. However, the macrophage cell lines, J774A.1 and P388D1, did not exhibit amoebicidal activity. Macrophage conditioned medium prepared from RAW264.7 macrophages mediated cytolysis of L929 tumor cells but had no effect on N. fowleri amoebae. In addition, neither recombinant tumor necrosis factor nor recombinant interleukin‐1 exhibited amoebicidal activity. Scanning electron microscopy of co‐cultures revealed that N. fowler bound to activated peritoneal macrophages and RAW264.7 macrophages. These results suggest that RAW264.7 macrophages treated in vitro with lipopolysaccharide are similar to macrophages activated in vivo in that they effect contact‐dependent cytolysis of Naegleria fowleri amoebae. The RAW264.7 macrophages are unlike primary macrophage cultures in that they either do not release soluble amoebicidal factors into the conditioned medium or they release insufficient quantities.
Naegleria lovaniensis tarasca New Subspecies, and the Purepecha Strain, a Morphological Variant of N. I. lovaniensis, Isolated from Natural Thermal Waters in Mexico
Authors: RIVERA FERMIN , CERVA LUBOR , MARTINEZ JULIO , KELETI GEORG , LARES FERNANDO , RAMIREZ ELIZABETH , BONILLA PATRICIA , GRANER SCOTT R. , SAHA ASISH K. , GLEW ROBERT H. 
Published: May 2007

ABSTRACTAmoebae were isolated from a natural thermal water source in Michoacaan, Mexico, in September 1986. Two 500‐ml samples were taken from pools with water at 45°C and 46°C and concentrated at 2,000 g for 15 min. The sediment was seeded on nonnutritive agar plates and incubated at 42°C. The isolates were axenized in bactocasitone‐serum medium. The identification of the isolates was based on their morphology, total protein and isoenzyme patterns by agarose isoelectric focusing, serology, fine structure, agglutination with Concanavalin A, sensitivity to trimethoprim, capacity to kill mice, and their cytopathic effect in Vero cells. The results showed several morphophysiological, biochemical and serological differences between the isolates and the type strain Aq/9/1/ 45D of Naegleria lovaniensis. These remarkable differences provide sufficient evidence to consider one of the isolates a new subspecies, and the other one a morphological variant of N. l. lovaniensis, which can be differentiated from other Naegleriae by their morphology, biochemistry, serology and physiology. The authors propose the name tarasca for the subspecies and purepecha for the morphological variant.
Populational Changes of the Enteric Protozoans Opalina spp. and Nyctotherus cordiformis During the Ontogeny of Anuran Tadpoles
Authors: SCHORR MARK S. , ALTIG RONALD , DIEHL WALTER J. 
Published: May 2007

ABSTRACT. We studied ontogenetic population changes of Opalina and Nyctotherus cordiformis in eight species of tadpoles from 10 sites in east‐central Mississippi. Most tadpoles acquired Opalina early in development, while the acquisition of N. cordiformis was variable. Developmental stage, species and collection site explained significant amounts of the variation in Opalina density of tadpoles (F= 11.6; df = 27, 235; P < 0.0001) and metamorphs (F= 7.31; df = 24, 84; P < 0.0001). Relationships between Opalina density and host stage showed either (1) a gradual decrease or (2) a gradual increase throughout host ontogeny. Opalina densities declined during metamorphosis. Density variations of N. cordiformis were explained by host species of tadpoles (F= 9.30; df = 7, 142; P < 0.0001) and by host species and stage of metamorphs (F= 5.85; df = 8, 62; P < 0.0001).The length of larval period, habitat duration and generation time of the protozoans are suggested as major modifiers of the protozoan densities. Hosts with long larval periods show a decreasing population density and hosts with short developmental periods show a pattern of increasing density. Neither pattern was detected in tadpoles from temporary sites. Metamorphic declines in protozoan density, but not necessarily the loss of protozoans, reflect metamorphic alterations of the gut common to all hosts.
Ascogregarina saraviae N. Sp. (Apicomplexa: Lecudinidae) in Lutzomyia lichyi (Diptera: Psychodidae)
Authors: OSTROVSKA KATHERINE , WARBURG ALON , MONTOYA‐LERMA JAMES 
Published: May 2007

ABSTRACTAscogregarina saraviae n. sp. (Apicomplexa: Lecudinidae) is described from wild‐caught Lutzomyia lichyi (Diptera: Psychodidae) females. Gametocysts adhered to the hemocoel side of the genital accessory gland walls and oocysts were injected into their lumina. Sporulated oocysts were ellipsoidal, 12.4 × 5.8 (11.6–13.1 × 5.6–5.9) micrometers, contained eight sporozoites and a refractile residuum. The elongate form of A. saraviae n. sp. oocysts, and their more delicate walls, clearly distinguish them from oocysts of A. chagasi (Adler & Mayrink, 1961).