bluuebunny/crossref_metadata_2025_split huggingface dataset:
Life Cycle and Epizootiology of Amblyospora sp. (Microspora: Amblyosporidae) in the Mosquito, Aedes cantator1
Authors: ANDREADIS THEODORE G. 
Published: May 2007

ABSTRACTIn Aedes cantator, Amblyospora sp. is transovarially transmitted and has two developmental sequences. The life cycle is initiated in the adult female with the release of sporoplasms from binucleated spores not bounded by membranes, lying free within host oenocytes. Sporoplasms infect the developing oocytes and are transmitted to the filial generation when the eggs are laid. In some of the female progeny that hatch from infected eggs, diplokaryotic cells infect host oenocytes and divide by binary fission during merogony. Sporulation and spore formation do not occur until a blood meal is taken by the host and they coincide with the development and maturation of the oocytes to complete the cycle. In other female and all male progeny, pathogen development occurs within fat body tissue of the host where diplokaryotic cells divide by multiple fission during merogony to spread the infection. Sporulation in this developmental sequence is characterized by the secretion of an accessory membrane and the meiotic division of diplokaryotic sporonts, which result in the formation of octonucleated plasmodia that undergo cytokinesis to form eight haploid spores which are not perorally infectious to other mosquito larvae. There is no increase in the prevalence of either type of infection in field populations during juvenile development, indicating that there is no direct horizontal transmission of the pathogen within any one generation. Data obtained from laboratory rearings of infected progeny, however, show that infections cannot persist relying solely upon maternal‐mediated transmission and that some other mode of transmission must be operative for continued maintenance of this microsporidium in A. cantator.
Morphology and Morphogenesis of Fuscheria terricola n. sp. and Spathidium muscorum (Ciliophora: Kinetofragminophora)1
Authors: BERGER HELMUT , FOISSNER WILHELM , ADAM HANS 
Published: May 2007

ABSTRACTThe morphology and morphogenesis of the kinetofragminophoran soil ciliates, Fuscheria terricola n. sp. and Spathidium muscorum Dragesco & Dragesco‐Kerneis, 1979, are described. Stained specimens (protargol) are characterized biometrically. The new species differs from the other species of the genus in its body size, body shape, number of kineties, length of extrusomes, and habitat. Both species have telokinetal stomatogenesis, which commences with a proliferation of kinetosomes at those kineties which bear the brosse. Fuscheria terricola does not have a complex perioral ciliature; indeed, it might be that this species has only monokinetids. Thus only a proliferation of kinetosomes and the separation of the kineties takes place in the prospective division furrow. In contrast, S. muscorum differentiates short dikinetid kinetofragments in the region of the division furrow, which are arranged to form the perioral kinety of the opisthe in the intermediate and late stages of the stomatogenesis. The right part of the perioral kinety develops first. This and other studies show that telokinetal stomatogenesis proceeds very differently depending on the differentiation of the oral ciliature; however, detailed studies on the morphogenesis of kinetofragminophoran ciliates are still too few in number for subtypes to be defined.
The Genera Barrouxia, Defretinella, and Goussia of the Coccidian Family Barrouxiidae (Protozoa, Apicomplexa)1
Authors: LEVINE NORMAN D. 
Published: May 2007

ABSTRACTThe apicomplexan family Barrouxiidae Léger, 1911 is reviewed and revised on the basis of present information. It includes the genera Barrouxia Schneider, 1885 with ten named species, Defretinella Henneré, 1966 with one named species, and Goussia Labbé, 1896 with 25 named species. The family is characterized by having bivalved sporocysts with a longitudinal suture line. Available information, admittedly spotty, is given for each species on oocyst, sporocyst and sporozoite structure, and on locus of sporulation. The following seven new combinations are made: Goussia flaviviridis (Setna & Bana, 1935) n. comb. in the gecko Hemidactylus flaviviridis; G. hyalina (Léger, 1898) n. comb. in an unidentified aquatic beetle; G. lacazei (Labbé, 1895) n. comb. in the centipedes Lithobius forficatus and L. martini; G. metchnikovi (Laveran, 1897) n. comb. in the gobies Gobio gobio and G. albipinnatus; G. schaudinniana (Pinto, 1928) n. comb. in the centipede Lithobius forficatus; G. stankovitchi (Pinto, 1928) n. comb. in the small bleak Alburnus alburnus, the bream Abramis brama, and the red roach Scardinius erythrophthalmus; Goussia sp. (Dogel' Akhmerov, 1959) nov. comb. in the freshwater fish Gnathopogon chankaensis.
Ultrastructural Localization of Monoclonal IgG Antibodies for Antigenic Sites of Eimeria tenella Oocysts, Sporocysts, and Sporozoites1
Authors: SPEER CLARENCE A. , WONG ROSIE B. , SCHENKEL ROBERT H. 
Published: May 2007

ABSTRACTMonoclonal IgG antibodies against sporozoites of Eimeria tenella were obtained from the ascites fluid of BALB/c mice. Oocysts, sporocysts, and sporozoites were exposed to medium 199, normal ascites fluid, or monoclonal antibodies 1A, 9D, 3D3II, or 2G8f. Specimens were then incubated with ferritin‐conjugated goat anti‐mouse IgG antibody. Ferritin was uniformly distributed over the surface of sporozoites exposed to 1A, 9D, or 3D3II; ferritin was localized in patches on sporozoites exposed to 2G8f. A uniform layer of ferritin was present on the inner layer of oocyst walls and on the Stieda body and outer surface of sporocysts exposed to 1A, 9D or 3D3II. In specimens treated with 2G8f, ferritin was present on the inner layer of the oocyst wall and the Stieda body, but not on the sporocyst wall. No ferritin was found on specimens exposed to medium 199 or normal ascites fluid. Monoclonal antibodies 1A, 9D, and 3D3II, but not 2G8f, caused complement‐mediated lysis of sporozoites. These findings indicate that oocysts, sporocysts, and sporozoites of E. tenella contain common antigens specific for each monoclonal antibody tested.
Patterns of DNA Synthesis and Cell Division in Marine Dinoflagellates1
Authors: KARENTZ DENEB 
Published: May 2007

ABSTRACTChanges in mean cell size, DNA and cell density were monitored at 6‐h intervals for 72 h in populations of six species (eight clones) of marine dinoflagellates to determine the temporal relationships between the cell cycle events of DNA replication and cytokinesis. Batch cultures were maintained at 15 or 20°C on a 12‐h light: 12‐h dark photoperiod. Cell densities and size frequency distributions were determined conductimetrically and the amount of DNA within populations was measured fluorometrically. A variety of intra‐ and interspecific relationships were observed, ranging from parallel phasing of cell cycle processes to variations which involved the temporal uncoupling of DNA synthesis from the phased pattern of cell division which is characteristic of dinoflagellate cell cycles. Daily growth rates of individual populations varied from 0.05 (Gymnodinium nelsoni) to 2.08 (Amphidinium carteri) cell divisions day‐1and DNA doubling rates ranged from 0 to 1.14 day‐1. Mean doubling rates for DNA were usually 30–40% lower than those for cells. The degree of difference in these rates and the amount of variability evident in cell cycle sequences may be major factors in determining the rate and extent of development of dinoflagellate populations in nature.
Nuclease Digestion of Chromatin from the Eukaryotic Algae Olisthodiscus luteus, Peridinium balticum, and Crypthecodinium cohnii1, 2
Authors: SHUPE KATHLEEN , RIZZO PETER J. 
Published: May 2007

ABSTRACTChromatin from a uninucleate dinoflagellate, Crypthecodinium cohnii, a binucleate dinoflagellate, Peridinium balticum, and a chromophyte, Olisthodiscus luteus, was examined by nuclease digestion and the results were compared to those from vertebrates. Gel analysis of the products of staphylococcal (micrococcal) nuclease digestion revealed a DNA repeat unit of 220(±5) base pairs for O. luteus and 215(±5) for P. balticum. Limit digestion gave a core particle of 140 base pairs, revealing that these longer repeat sizes are due to longer linker regions. No repeating subunit structure was found upon electrophoresis of digests of C. cohnii nuclei. Examination of the DNA fragments produced by DNAse I digestion of nuclei isolated from P. balticum and O. luteus showed the same ladder of ten base multiples as seen in chromatin from other eukaryotes. Examination of the kinetics of digestion by DNAse II of Peridinium chromatin revealed less susceptibility when compared to DNAse I digestions while 70% of Olisthodiscus chromatin and 35% of C. cohnii chromatin was sensitive to DNAse II. These data, taken together with previous results from Euglena, indicate that while algal chromatin is similar to that of higher eukaryotes in regard to DNAse I and II action, it differs in that the linker DNA is longer. In addition, the Hl‐like histone from O. luteus and P. balticum is located in the linker DNA as in higher eukaryotes.
Regulation of Ribosomal RNA Transcription During Differentiation of Acanthamoeba castellanii: A Review
Authors: PAULE MARVIN R. 
Published: May 2007

ABSTRACTDuring the cellular differentiation induced by starvation of Acanthamoeba castellanii, the expression of a number of genes is regulated. Evidence is reviewed that at least one of these, the precursor ribosomal RNA transcription unit, is regulated at the level of transcription. The structure of the rRNA transcription unit and of the RNA polymerases responsible for transcription in Acanthamoeba are reviewed. Utilizing an in vitro transcription system constructed from these components, preliminary evidence has been obtained that pre‐rRNA gene expression is regulated by a modification of RNA polymerase I that affects the enzyme's ability to participate efficiently in the initiation of transcription. These results are reviewed in relation to other known mechanisms of transcriptional regulation in eukaryotes.
Appendages Associated with Glugea stephani, a Microsporidan Found in Flounder1
Authors: TAKVORIAN PETER M. , CALI ANN 
Published: May 2007

ABSTRACTDuring an electron microscopic study of Glugea stephani, three morphologically distinct tubular appendages that are continuous with the sporoblast plasmalemma were observed. The tubules were designated as: type I, 45–50 nm in diameter and 600–900 nm in length; type II, 25–35 nm in diameter, averaging 1300 nm in length; type III, 50–70 nm in diameter and with an indeterminate length, which often exceeds 3000 nm. Type III tubules contain regularly spaced, electron‐dense particles that are approximately 30 nm in diameter. Since many genera of microsporida have some type of appendage, which may eventually be utilized for taxonomic purposes, we propose the formation of a system of serially numbered detailed descriptions of these structures to promote uniformity and clarity in future publications.
Leishmania: Chemotaxic Responses of Promastigotes and Macrophages In Vitro1
Authors: BRAY R. S. 
Published: May 2007

ABSTRACTPromastigotes of Leishmania move progressively up a concentration gradient of: various sugars, specific sugars attracting individual species of Leishmania; serum albumin and another unidentified constituent of serum; hemoglobin; and a factor generated by promastigotes in NNN medium. The movement of promastigotes up a concentration gradient of serum is optimal at a pH of 6.4 to 6.8 and a temperature of 28°C and above. Cholinergic and adrenergic agents did not affect the attraction of serum for promastigotes. and cyclic nucleotides, inflammatory mediators, and macrophage products were not chemotaxic. It is postulated that the sugar chem‐otaxins influence the movement of promastigotes from the sand fly midgut to the esophagus, and serum chemotaxins may play a part in the entry of promastigotes into the skin of a mammal from the proboscis.Macrophages, the host cell of the obligate intracellular Leishmania species, were not attracted to any product of promastigotes. When, however, promastigotes interact with serum, complement is activated to form C5a which is chemotaxic for macrophages. Activation of complement by promastigotes is, at least partially, by the alternate pathway. Other chemotaxins resulting from promastigote interaction with serum may also be present. Promastigotes may also produce inhibitors of C5a activity.
Monoclonal Antibodies to Toxoplasma Cell Membrane Surface Antigens Protect Mice from Toxoplasmosis1,2
Authors: JOHNSON ALAN M. , MCDONALD P. J. , NEOH S. H. 
Published: May 2007

ABSTRACTGroups of mice were given an intraperitoneal injection of one of six monoclonal antibodies to Toxoplasma gondii, a mixture of equal amounts of five monoclonal antibodies to T. gondii, or the murine myeloma protein MOPC 21, and challenged with either a highly virulent or moderately virulent parasite strain. Two monoclonal antibodies (FMC 19 and FMC 22) conferred total protection against the moderately virulent challenge, with all mice surviving, whereas 90% of control mice died. FMC 19 and FMC 22 also conferred significant protection against the highly virulent challenge as indicated by a prolonged mean time to death (MTD) of immunized compared with control groups of mice. One monoclonal antibody (FMC 23) and the mixture of five antibodies gave significant protection against the moderately virulent challenge only. Passive immunization with dilutions of FMC 22 antibody indicated that the lowest serum titer needed to confer significant protection to mice against a moderately virulent Toxoplasma challenge was 1/640. Mice challenged with highly virulent tachyzoites that had been preincubated with FMC 22 had a significantly longer MTD than mice challenged with highly virulent tachyzoites that had been preincubated with MOPC 21 or phosphate buffered saline, pH 7.2 (PBS). Immunoprecipitation and autoradiography of radiolabeled tachyzoites confirmed that FMC 19 was directed against a 35,000 molecular weight (mol. wt.) antigen and FMC 22 was directed against a 14,000 mol. wt. fraction. The potential for use of single antigens as protective immunogens in preventing toxoplasmosis is raised.
Identification of Surface Antigens of Sarcocystis muris (Coccidia)
Authors: ABBAS MOHAMMED K. , POWELL EDWIN C. 
Published: May 2007

ABSTRACTZoites of Sarcocystis muris were recovered from the skeletal muscles of infected mice by trypsin digestion. Extracts of zoites prepared by freeze‐thaw, Triton X‐100 (0.1%), or a combination of the two treatments contained antigenic components. Testing of these antigens by agar gel diffusion and immunoelectrophoresis against sera from infected mice showed one major precipitin band.SDS‐polyacrylamide‐gel electrophoresis (SDS‐PAGE) of the extracts revealed at least eight detectable polypeptides ranging in molecular weight from 10,000 to 220,000. The antigenic components of the extract were identified by labeling the parasite surface with [125I] and precipitation of the [125I]‐labeled antigens with immune sera. Analysis of the immunoprecipitates by SDS‐PAGE and autoradiography revealed three antigens with molecular weights of 27,500, 43,000 and 90,000. The smallest of these was the predominant antigen as suggested by labeling intensity.
Chemically Defined Media for the Cultivation of Naegleria: Pathogenic and High Temperature Tolerant Species
Authors: NERAD THOMAS A. , VISVESVARA GOVINDA , DAGGETT PIERRE‐MARC 
Published: May 2007

ABSTRACTChemically defined minimal media for the cultivation of high temperature tolerant and pathogenic Naegleria spp. have been developed. A defined minimal medium, identical for N. fowleri and N. lovaniensis, consists of eleven amino acids (arginine, glycine, histidine, isoleucine, leucine, methionine, phenylalanine, proline, threonine, tryptophan, and valine), six vitamins (biotin, folic acid, hemin, pyridoxal, riboflavin, and thiamine), guanosine, glucose, salts, and metals. Three of the four strains of Naegleria fowleri tested (ATCCr̀30100, ATCCr̀30863, and ATCCr̀30896) and two strains of N. lovaniensis (ATCCr̀30467 and ATCCr̀30569) could be cultured beyond ten subcultures on this medium. For N. fowleri ATCCr̀30894 diaminopimelic acid, or lysine, or glutamic acid was also required. Mean generation time was reduced and population density increased for all strains with the introduction of glutamic acid. Glucose could be eliminated from the minimal medium only if glutamic acid was present. Without glucose, mean generation time increased and population density decreased. Diaminopimelic acid could substitute for lysine for ATCCr̀30894, indicating that Naegleria species may synthesize their lysine via the DAP pathway. Naegleria fowleri ATCCr̀30100 could be adapted to grow without serine or glycine in the minimal medium with glutamic acid added, but with mean generation time increased and population density decreased. The strain could be grown in the minimal medium in the absence of metals. For growth of N. australiensis ATCCr̀30958, modification of the medium by increasing metals ten‐fold, substituting guanine for guanosine and adding lysine, glutamic acid, and six vitamins (p‐aminobenzoic acid, choline chloride, inositol, vitamin B12, nicotinamide, and Ca pantothenate) was required.
Patterned Arrays of Intramembranous Particles in the Bristle Cilia of Three Different Species of Euplotes1
Authors: DALLAI ROMANO , LUPORINI PIERANGELO 
Published: May 2007

ABSTRACTFreeze‐fractured cells of three marine species of Euplctes (E. crassus, E. raikovi, and E. rariseta) show bristle cilia with patterned arrays of intramembranous particles. Such arrays are essentially of three types, in different positions along the bristle shaft. One array is located near the bristle base and shows a plate‐like shape. It appears in a close spatial correspondence with the lasiosome network, which is a structure consisting of interconnected electron‐dense bodies lying in between the peripheral axonemal doublets and the bristle membrane. The second type of array, apparently typical of only E. raikovi, consists of eight to ten longitudinal rows of particles that occupy most of the intermediate portion of the bristle. The third type of array appears differently shaped in different species and occurs at the bristle apex.
An Ultrastructural Study of Mitosis in a Marine Dinoflagellate: Prorocentrum minimum1
Authors: FRITZ LAWRENCE , TRIEMER RICHARD E. 
Published: May 2007

ABSTRACTAn ultrastructural study on mitosis in the marine dinoflagellate Prorocentrum minimum is described. Early in mitosis the nuclear membrane invaginates in the area of the Golgi apparatus. Additional membrane‐lined channels form within the nucleus as the Golgi apparatus separates and moves toward opposite spindle poles. Microtubules appear within the channels and make contact with distinct kinetochore‐like structures on the cytoplasmic side of the channels adjacent to the site of chromosome attachment. By mid‐mitosis two or three parallel channels dissect the nucleus perpendicular to the suture plane of the cell. Chromosome separation thus occurs perpendicular to the suture plane. An additional group of microtubules extends posteriorly from the flagellar apparatus towards the nucleus but has no apparent role in mitosis. Mitosis in P. minimum is compared to that of P. micans and to other dinoflagellates.
Flagellar Adherence of Crithidia fasciculata Cells in Culture1
Authors: HUGHES DALLAS , SIMPSON LARRY , SCHNEIDER CAROL AKAWIE 
Published: May 2007

ABSTRACTIn early log phase cultures of several of the drug‐resistant mutants of Crithidia fasciculata that we have previously obtained, a high percentage of cells attach in pairs at the base of the flagellum. This process, which we have termed “flagellar adherence,” lasts for several hours in some cases and occasionally involves changes in cell morphology. The attachment occurs optimally in gently agitated cultures. Flagellar adherent pairs can be disassociated by vigorous agitation; the pairs reappear in the culture within one to three h after disassociation. These paired forms can be clearly distinguished from the normal cell division forms. Clones of flagellar adherent‐competent mutant strains are uniformly able to form these pairs in culture. A low percentage of flagellar adherent forms can be induced in wild type cells by glucose starvation.
Stage‐Dependent Effects of Chloroquine on Plasmodium falciparum In Vitro1
Authors: YAYON AVNER , WAA JOHN A. VANDE , YAYON MALKA , GEARY TIMOTHY G. , JENSEN JAMES B. 
Published: May 2007

ABSTRACTThe erythrocytic developmental cycle of Plasmodium falciparum can be conveniently divided into the ring, trophozoite, and schizont stages based on morphology and metabolism. Using highly synchronous cultures of P. falciparum, considerable variation was demonstrated among these stages in sensitivity to chloroquine. The effects of timed, sequential exposure to several clinically relevant concentrations of chloroquine were monitored by three techniques: morphological analysis, changes in the rate of glucose consumption, and changes in the incorporation of 3H‐hypoxanthine into parasite nucleic acids. All three techniques gave essentially identical results. The trophozoite and schizont stages were considerably more sensitive to the drug than ring‐stage parasites. Chloroquine sensitivity decreased as nuclear division neared completion. The increase in chloroquine sensitivity was coincident with a marked rise in the rate of glucose consumption and nucleic acid synthesis. The rate of nucleic acid synthesis decreased as schizogony progressed while glucose consumption continued at high rates during this process. The degree of chloroquine sensitivity was not highly correlated with either metabolic activity.
Effect of Gossypol upon Motility and Ultrastructure of Trypanosoma cruzi1
Authors: BLANCO ANTONIO , AOKI AGUSTIN , MONTAMAT ENRIQUE E. , ROVAI LEONOR E. 
Published: May 2007

ABSTRACTGossypol, a polyphenolic compound from the cotton plant, immobilizes and structurally alters cultured Trypanosoma cruzi epimastigotes. Ultrastructural changes observed in gossypol‐treated parasites were first detected in the kinetoplast and mitochondrion. At 50 μM concentration, much disorganization was evident after 5 min of incubation. With 25 μM gossypol, the same effect occurred after 30 min. Most epimastigotes were rounded, containing various membranous structures that could not be related to known cell components.
The Spread of Infection by the Microsporidan, Nosema disstriae, in Insect Cell Lines1
Authors: KURTTI TIMOTHY J. , TSANG K. ROGER , BROOKS MARION A. 
Published: May 2007

ABSTRACTNosema disstriae, a parasite of the forest tent caterpillar, Malacosoma disstria, was cultured with cell lines UMN‐MDH‐1 (Malacosoma disstria), IPLB‐1075 (Heliothis zea), and BTC‐32 (Triatoma infestans). Infected cultured cells were used to infect the healthy cell lines. Electron micrographs of thin sections of 6‐day‐old cultures revealed infected cells that exocytosed vesicles containing vegetative and immature sporulating forms of the parasite. Some of these forms were believed to be responsible for intercellular transmission of the parasite. The spread of infection was augmented by culturing the cells at high densities; if the density was too low, there was little or no cross infection. Cross infection was inhibited, but not blocked completely, by high osmolality of the culture medium. The yield of spores from a confluent cell monolayer at the end of growth was generally 1–4 × 107 per ml of culture medium.