bluuebunny/crossref_metadata_2025 huggingface dataset:
A Perspective on Protistan Nomenclature
Authors: PATTERSON DAVID J. , LARSEN JACOB
Published: May 2007

ABSTRACT. The nomenclature of protists is more complicated than that of plants or animals because more than one code of nomenclature applies (i.e. the taxa may be ambiregnal), because of the frequent absence of type material, and because of changing perspectives of the phylogenetic relationships of various groups of protists. These factors often lead to uncertainty over the meaning of names of taxa. If nomenclatural instability is to be avoided, some changes in current practices are required. The nature of the problems and some possible changes are discussed.
Transkinetoplastidy—A Novel Phenomenon Involving Bulk Alterations of Mitochondrion‐Kinetoplast DNA of a Trypanosomatid Protozoan1,2
Authors: LEE SHENG‐YIH , LEE SHU‐TONG , CHANG KWANG‐POO
Published: May 2007

ABSTRACT. Dramatic and consistent changes of mitochondrial or kinetoplast DNA (kDNA) were observed in certain variants of Leishmania amazonensis (A variants) selected in vitro for arsenite‐resistance. This was found initially by comparing different lots of wild‐type cells and their respective A variants resistant to 30 μM arsenite. The kDNAs isolated from these two groups had different restriction patterns and hybridized poorly to each other, whereas those from different lots within each of the two groups were identical. Hybridization data showed an overall identity of less than 10−3 between total kDNAs of the two groups. This difference was further examined in three independent series of variants, which were selected from three different clones for resistance to graded concentrations of arsenite (5–30 μM). In all three series, their kDNAs were found to change abruptly in an identical pattern at a late step of the selection process, i.e. A variants resistant to 15 μM or 30 μM arsenite. There was no apparent loss of kDNA in the process. Most of the changes observed appear to involve a shift in either the dominance or the copy number of different minicircle subclasses. Surprisingly, the kDNAs of tunicamycin‐resistant variants (T variants) were also found to undergo similar changes. Genetic changes previously described in both A and T variants are limited to their nuclei. Namely, different chromosomal regions are amplified to produce large DNA circles which are responsible for the drug‐resistant phenotypes. Interestingly, other arsenite‐resistant clones without such chromosomal DNA amplification (A'variants) had kDNA of the wild‐type pattern. The profound changes of kDNA observed are unprecedented. We propose the term “transkinetoplastidy” for this phenomenon to distinguish it from dyskinetoplastidy or the loss of kDNA described previously in trypanosomatid protozoa. This phenomenon is discussed with respect to the possible mechanisms of its generation, regulation and relation to the drug‐resistant phenotypes.
Serial Subcultivation of Giardia lamblia in Keister's Modified TYI‐S‐33 Medium Containing Ultroser G
Authors: BIFULCO JOSEPH M. , SCHAEFER FRANK W.
Published: May 2007

ABSTRACT. The ability of Giardia strains of the duodenalis type to grow in Keister's modified TYI‐S‐33 medium varies with serum lot. Recently, strains of Giardia including MR4, WB, and Human‐1‐Portland, have been cultivated in Keister's modified TYI‐S‐33 medium containing the serum substitute Ultroser G and have been cultured serially at least 40 times. An optimal concentration of 8% Ultroser G promotes maximal growth in Keister's modified TYI‐S‐33 medium for all three strains. This concentration of Ultroser G will produce a two‐log increase in the number of trophozoites in approximately three days post‐inoculation. Generation times for the trophozoites ranging from 6 to 11 h have been achieved in Keister's modified TYI‐S‐33 containing 10% adult bovine serum and from 8 to 13 h in Keister's modified TYI‐S‐33 with 8% Ultroser G. Despite the excellent growth of Giardia strains in medium containing Ultroser G, the maximum trophozoite density is only about half of that achieved in Keister's modified TYI‐S‐33 medium supplemented with 10% adult bovine serum. Comparisons of trophozoites grown with serum or the serum substitute reveal no discernable differences in morphology and motility. Additionally, these strains have been successfully cryopreserved and revived in Keister's modified TYI‐S‐33 medium supplemented with Ultroser G. Because Ultroser G is a characterized mixture of six main groups of ingredients (growth factors, adhesion factors, mineral trace elements, hormones, binding proteins, and vitamins), the variability in cell proliferation that may occur when changing serum lots should be minimized when using this product.
Evidence for Meiosis in the Testate Amoeba Arcella
Authors: MIGNOT JEAN‐PIERRE , RAIKOV IGOR B.
Published: May 2007

ABSTRACT. Electron microscopic studies of Arcella vulgaris have revealed a sexual process occurring in cysts. The evidence includes: I) synaplonemal complexes in prophasic nuclei. 2) two consecutive divisions different from vegetative mitosis, 3) degeneration of certain products of these nuclear divisions, and 4) fusion of nuclei indicating karyogamy. The process is apparently autogamy preceded by a two‐division meiosis. The testate amoebae can no longer be considered asexual.
A Method for Assessing the Migratory Response of Naegleria fowleri Utilizing [3H]Uridine‐Labeled Amoebae
Authors: BRINKLEY CARLTON , MARCIANO‐CABRAL FRANCINE
Published: May 2007

ABSTRACT. A new procedure is described to assay the migratory response of Naegleria fowleri (ATCC 30894) amoebae to potential chemoattractants. The method utilizes a blind‐well Boyden chemotaxis chamber, two micropore filters of different construction, and amoebae‐labeled with [3H]uridine. The technique was standardized by determining the influence of incubation time, filter construction, filter pore size and geometry, amoebae to filter pore ratio, and chemoattractant concentration. Radiolabeled amoebae were placed in Boyden chambers that contained the combination of an upper polycarbonate filter with distinct pores with a diameter of 8 μm and a lower filter of nitrocellulose with a 150‐μm depth to separate the wells. A ratio of two amoebae to one filter pore and a 2‐h incubation period were chosen to obtain optimal migration conditions. Nerve cell extract was used as the chemoattractant. The migratory responses of both highly pathogenic and weakly pathogenic strains of N. fowleri to nerve cell extract were compared using either the radiolabel procedure or the conventional single filter, leading‐front method. Using either method, a highly pathogenic cloned strain of N. fowleri amoebae moved in a directiona manner (chemotactically)in vitro to B103 rat neuroblastoma cell extract. In contrast, a weakly pathogenic strain of amoebae responded in a nondirectional manner (chemokinetically) to nerve cell extract. While both the leading‐front assay and the radiolabel assay give accurate results, the measurement of radiolabeled cells allows one to test a greater number of attractants in one assay and the procedure eliminates observer bias.
Non‐Coding DNA in Macronuclear Chromosomes of Hypotrichous Ciliates
Authors: HERRICK GLENN
Published: May 2007

ABSTRACT. Massive elimination of sequences occurs in the development of the macronucleus of hypotrichous ciliates. The surviving sequences are presumed to have functions in the macronucleus; what little is known about non‐coding macronuclear sequences is reviewed. The 1.7 kbp macronuclear chromosome that carries a histone H4 gene consists primarily of non‐coding DNA 5’of the histone gene. This region is shown by sequence comparison to carry several perfectly conserved sequence blocks up to 14 bp long, scattered amongst regions which have evolved greatly since the divergence of Oxytricha nova and Stylonychia lemnae. This result is consistent with the suggestion of Harper and Jahn [Harper, D. S. & Jahn, C. L. 1989. Actin, tubulin and H4 histone genes in three species of hypotrichous ciliated protozoa. Gene, 75:93–107] that this large non‐coding 5’region may be involved in the transcriptional regulation of the histone H4 gene carried on the 1.7 kbp chromosome. Very little is known about transcriptional control in hypotrichs; identification of conserved non‐coding sequences of orthologous hypotrich genes promises to provide clues to potential cis‐acting control signals.
NADP‐Specific Isocitrate Dehydrogenase from the Simian Malaria Parasite Plasmodium knowlesi: Partial Purification and Characterization
Authors: SAHNI SANJEEV K. , SAXENA NALINI , PURI SUNIL K. , DUTTA GURU P. , PANDEY VIKASH C.
Published: May 2007

ABSTRACT. Cell‐free schizonts of Plasmodium knowlesi, a simian malaria parasite, possess significant isocitrate dehydrogenase (IDH) activity, about 90% of which is contributed by the NADP‐specific enzyme that is localized in the cytosolic fraction. The enzyme has been partially purified by affinity chromatography using Blue sepharose CL‐6B. Although unstable in nature, it is stabilized by citrate and glycerol. Kinetic studies with dl‐isocitrate and NADP yielded hyperbolic curves with Michaelis constants of 0.210 and 0.038 mM, respectively. Manganous or magnesium ions are essential for activity. The enzyme is thermosensitive, shows maximum activity at pH 8.0, and has a molecular mass of about 48.5 kDa. It is strongly inhibited by thiolblocking agents but protected against them by thiol‐providing agents. Cupric and argentic ions also have a marked inhibitory effect on its activity. The enzyme is significantly inhibited by chloroquine and oxytetracycline in vitro, but to a lesser degree by tetracycline.
Identification of Tetrahymena Ciliary Surface Proteins Labeled with Sulfosuccinimidyl 6‐(Biotinamido) Hexanoate and Concanavalin A and Fractionated with Triton X‐114
Authors: DENTLER WILLIAM L.
Published: May 2007

ABSTRACT. Tetrahymena thermophila cells were labeled with sulfosuccinimidyl 6‐(biotinamido) hexanoate, a sensitive nonradioactive probe for cell surface proteins, and Western blots of axonemes and ciliary membrane vesicles were compared to cilia fractionated with Triton X‐114 (TX‐114) in order to study the orientation of ciliary membrane proteins. Greater than 40 ciliary surface polypeptides, from >350 kDa to <20 kDa, were resolved. The major surface 50–60 kDa proteins are hydrophobic and partition into the TX‐114 detergent phase. Two high molecular weight proteins, one of which is biotinylated, comigrate with the heavy chains of ciliary dynein, sediment at 14S in a sucrose gradient, and partition into the TX‐114 aqueous phase. Fractions containing these high molecular weight proteins as well as fractions enriched in 88‐kDa and 66‐kDa polypeptides contain Mg2+‐ATPase activities. Detergent‐solubilized tubulins partition into the TX‐114 aqueous phase, are not biotinylated, and must not be exposed to the ciliary surface. The detergent‐insoluble axoneme and membrane fraction contains a 36‐kDa polypeptide and a portion of the 50‐kDa polypeptides that otherwise partition into the detergent phase. These polypeptides could not be solubilized by ATP or by NaCl extraction and appear to be associated with pieces of ciliary membrane tightly linked to the axoneme. The ciliary membrane polypeptides were also tested for Concanavalin A binding and at least sixteen Con A‐binding polypeptides were resolved. Of the major Con A‐binding polypeptides, three are hydrophobic and partition into the TX‐114 detergent phase, three partition into the TX‐114 aqueous phase, and four partition exclusively in the detergent‐insoluble fraction, which contains axonemes and detergent‐resistant membrane vesicles.
Factors Affecting the Salinity Tolerance of the Freshwater Cryptomonad Chilomonas paramecium
Authors: UKELES RAVENNA , WIKFORS GARY H. , FERRIS GAIL E.
Published: May 2007

ABSTRACT. The capacity of the freshwater cryptomonad Chilomonas paramecium to develop a tolerance for seawater in the growth medium was investigated as part of a research program exploring potential microbial food sources for estuarine bivalve mollusks. By gradually increasing the percentage of estuarine seawater included in a freshwater culture medium over the course of 10 years, strains were obtained that tolerate from 16 to 32% seawater (highest salinity 10.5 ppt), achieving equivalent final densities with similar gross biochemical composition. However, after subculture in seawater‐containing media for over 20 years, growth rates in more‐saline media remained appreciably slower than in low‐salinity media. Reduction of C. paramecium growth rate by seawater was found to be exacerbated in media with an initial pH of 3.5 as compared with pH 4.0–5.0, suggesting either a specific H+ effect upon metabolism of the medium carbon source (lactic acid) or a general cation effect upon nutrient uptake or cell metabolism. By contrast, depression of growth rates at high salinity was ameliorated by eliminating sodium‐phosphate enrichments in growth media. This suggests that cations in the phosphate salt were contributing to cation‐mediated growth inhibition. Results indicate a potential for C. paramecium, cultured in moderately saline media with no phosphate enrichments, to be used as a carbohydrate supplement for laboratory and hatchery feeding of estuarine bivalve mollusks.
Comparison of the Host Ranges and Antigenicity of Cryptosporidium parvum and Cryptosporidium wrairi from Guinea Pigs
Authors: CHRISP CLARENCE E. , SUCKOW MARK A. , FAYER RONALD , ARROWOOD MICHAEL J. , HEALEY MARK C. , STERLING CHARLES R.
Published: May 2007

ABSTRACT. Oocysts of a Cryptosporidium isolate from guinea pigs were not infectious for adult mice, but were infectious for two of three newborn calves and for suckling mice. However, oocysts isolated from calves or mice infected with guinea pig Cryptosporidium were not infectious for guinea pigs. Four isolates of C. parvum from calves were incapable of infecting weanling guinea pigs. Microscopic examination of tissue from the colon and cecum of suckling guinea pigs inoculated with C. parvum revealed sparse infection of some pups. These host range studies and previously described differences in 125I‐labeled oocyst surface protein profiles between Cryptosporidium sp. from guinea pigs and C. parvum suggest they are distinct species. We propose the name Cryptosporidium wrairi be retained. Studies with monoclonal antibodies indicate that C. wrairi and C. parvum are antigenically related.
Gregarina coronata N. Sp. (Apicomplexa: Eugregarinida) Described from Adults of the Southern Corn Rootworm, Diabrotica undecimpunctata howardi (Coleoptera: Chrysomelidae)
Authors: CLOPTON R. E. , PERCIVAL T. J. , JANOVY J.
Published: May 2007

ABSTRACT. Gregarina coronata n. sp. (Apicomplexa: Eugregarinida) is described from the adults of the Southern Corn Root Worm, Diabrotica undecimpunctata howardi (Coleoptera: Chrysomelidae). Measurements given are means, in micrometers, taken from mature gamonts in association. Primite: protomerite hemi‐ellipsoidal with basal tumidus, length 47.6, width 44.0, with cytoplasmic granule, apical crown apparent; deutomerite elongate ellipsoidal, length 227.9, width 81.3; epimerite absorbed into anterior in gamont, globular in trophozoite. Satellite: protomerite hemi‐ellipsoidal, truncated at association interface to appear trapezoidal, length 39.2, width 49.6, with cytoplasmic granule; deutomerite elongate ellipsoidal, length 240.6, width 80.2; epimerite absorbed into anterior in gamont. Association caudofrontal and often precocious, occurring during growth of trophozoites. Gametocysts spherical, 115.3 in diameter, 132.9 with hyaline coat; producing multiple oocyst chains under moist storage in 24–36 h. Oocysts very uniform in shape and size, dorsad: doliform, length 6.4, equatorial width 3.4, polar width 2.9; pleuron: dorso‐ventrally flattened, corpus concave with bicondylic termina; corpus height 0.98, width 4.44; terminus height 1.96, width 0.98.
The Light and Electron Microscopic Cytology of Janacekia adipophila N. Sp. (Microspora, Tuzetiidae), a Microsporidian Parasite of Ptychoptera paludosa (Diptera, Ptychopteridae)
Authors: LARSSON J. I. RONNY
Published: May 2007

ABSTRACT. The microsporidium Janacekia adipophila n. sp., a parasite of Ptychoptera paludosa larvae in Sweden, is described based on light microscopic and ultrastructural characteristics. Merogonial stages and sporonts are diplokaryotic. Merozoites are formed by rosette‐like division. Sporonts develop into sporogonial plasmodia with isolated nuclei. These plasmodia give rise to 8–16 sporoblasts by rosette‐like budding. A sporophorous vesicle is initiated by the sporogonial plasmodium. Sporoblasts and spores are enclosed in individual sporophorous vesicles. Granular inclusions of the vesicles, visible using light microscopy, discriminate sporogonial stages from stages of the merogony. The monokaryotic, fresh spores are oval with blunt ends, measuring 4.2‐6.3 × 9.1‐11.2 μm. Macrospores are formed in small numbers. The spore wall has three subdivisions and the exospore is electron‐dense. The polaroplast has two parts: closely arranged lamellae anteriorly, wider sac‐like compartments posteriorly. The isofilar polar filament, 191–264 nm wide, has 12‐13 coils, which are arranged in one layer in the posterior half of the spore. The electron‐dense inclusions of the sporophorous vesicle are modified during sporogony, and vesicles with mature spores are traversed by 21–27 nm wide tubules, which connect the exospore with the envelope of the vesicle. The walls of the tubules, the envelope of the vesicles, and the surface layer of the exospore are all identical double‐layered structures. The microsporidium is compared to microsporidia of Ptychopteridae and Tipulidae and to related microsporidia of the family Tuzetiidae.
Electron Microscopic Analysis of Circumsporozoite Protein Trail Formation by Gliding Malaria Sporozoites
Authors: STEWART MICHAEL J. , VANDERBERG JEROME P.
Published: May 2007

Immunoelectron microscopic techniques were utilized to characterize the morphology of circumsporozoite protein‐containing trails deposited on various substrates by gliding Plasmodium berghei and Plasmodium falciparum sporozoites. The basic components of the trails are beadlike particles, 25 to 90 nm in diameter, which are devoid of unit membrane and have an electronlucent center. Trails were captured on formvar‐covered grids coated with anticircumsporozoite protein monoclonal antibodies and compared with trails produced on uncoated formvar; the results suggest that material containing circumsporozoite protein forms the matrix within which the particles are embedded. The trails exhibit morphological features similar to those displayed by circumsporozoite precipitation reactions; of note is the demonstration of sheaths of circumsporozoite protein‐containing material that emanate from sporozoites prior to their gliding. The sheaths narrow into accumulations of electron‐dense material, which eventually taper to form typical trails. The structural manifestation of sheaths and other morphological details of the formed trails enables us to correlate sporozoite behavior during trail formation with the motile actions of gliding sporozoites observed by light microscopy.
Immobilization Antigens from Tetrahymena thermophila Are Glycosyl‐Phosphatidylinositol‐Linked Proteins
Authors: KO YOUNG‐GYU , THOMPSON GUY A.
Published: May 2007

We have studied four strains of Tetrahymena thermophila, each of which expresses a different allele of the SerH gene and produces a distinctive surface protein of the immobilization antigen (i‐antigen) class. Following exposure of the strains to [3H]ethanolamine or [3H]myristic acid, a protein corresponding in molecular mass to the characteristic i‐antigen for that strain became highly labeled, as determined by mobility in sodium dodecylsulfate‐polyacrylamide eiectrophoresis gels. Furthermore, antibodies raised to the i‐antigens of the T. thermophila strains selectively immunoprecipitated radioactive proteins having molecular mass identical to that of the i‐antigen characteristic for that particular strain. The lipid moieties labeled by [3H]myristate were not susceptible to hydrolysis by exogenous phosphatidylinositol‐specific phospholipase C from bacteria. However, when protein extraction was carried out in the absence of phospholipase C inhibitors, radioactive fatty acids derived from [3H]myristate were rapidly cleaved from the putative i‐antigens. On the basis of available data, it was concluded that T. thermophila i‐antigens contain covalently‐Iinked glycosyl‐phospha‐tidylinositol anchors.
Trypanosoma cruzi Infection of BSC‐1 Fibroblast Cells Causes Cytoskeletal Disruption and Changes in Intracellular Calcium Levels
Authors: LOW HOI PANG , PAULIN JEROME J. , KEITH CHARLES H.
Published: May 2007

ABSTRACT The disruption of vimentin and actin filaments of host BSC‐1 fibroblast cells by Trypanosoma cruzi was investigated using a mouse monoclonal anti‐vimentin antibody and rhodamine phalloidin, respectively. Indirect immunofluorescence microscopy demonstrated that infection of BSC‐1 cells by T. cruzi caused disruption of both cytoskeletal components. The disruption was greater as infection progressed. Mechanisms other than mechanical ones may play a role in the disruption since disrupted cytoskelelal elements were well removed from the parasites. In the determination of intracellular calcium concentrations using Fura‐2 AM, infected and uninfected cells both showed an initial increase in intracellular calcium levels. At later times of infection (3 to 5 days), intracellular calcium levels of infected cells were significantly lower than those of control cells. There was no specific localization of intracellular calcium in the infected host cells as determined by image analysis.
The Interface Between Air and Water: A Perturbation Source Eliciting Adaptive Behaviour in Ciliates
Authors: RICCI NICOLA , ERRA FABRIZIO , RUSSO ANTONIO , BANCHETTI ROSALBA , Interface Water‐Air
Published: May 2007

ABSTRACT Interference with the water‐air interface, both direct (by contact with a flat, rigid surface) and indirect (by inducing a meniscus) caused the ciliated protozoa we investigated to actively collect in the water column or on the substrate directly under the area of altered surface tension. A crowding effect is observed in this “rest area” reaching plateau values within one hour after onset of the experiment. The simple experimental procedures described here induced analogous behaviour in both Paramecium caudatum (a swimmer) and Oxytricha bifaria (a crawler). The ciliates seem in this reaction to be seeking a refuge from vibrations transmitted by the free interface. Our discovery is discussed in its implications for the adaptive biology and ecology of these micro‐organisms.
Effects of Cadmium in Stylonychia lemnae, Stylonychia notophora and Oxytricha granulifera: Isolation of a Cadmium‐Binding Protein
Authors: PICCINNI ESTER , IRATO PAOLA , CAVALLINI LETIZIA , AMMERMANN DIETER
Published: May 2007

ABSTRACT The effects of cadmium on three ciliates are reported here. Cultures of Stylonychia lemnae, Stylonychia notophora and Oxytricha granulifera were treated with different doses of Cd according to tolerance. The two species of Stylonychia are very sensitive to the metal, white O. granulifera tolerates higher doses. Adding 50 μM of Cd to the medium did not damage cells. The accumulated metal is almost totally present in the particulate fraction after day 3. Two Cd‐Zn linking fractions were separated from the soluble fraction of culture treated on day 1. The first protein linking 17 μg Cd/mg showed an ultraviolet absorption spectrum similar to that of Cd‐thioneins. Preliminary amino acid analyses indicated that it contained 13% cysteine. The second protein, linking 60 μg Cd/mg, was a glycoprotein. Its ultraviolet absorption spectrum and amino acid analysis showed that this binding protein was far from being a metallothionein: its cysteine content was very low and aromatic and cyclic residues were present. This Cd‐linking compound seems to be unique, since it was very different both from metallothioneins and chelatins isolated by other protozoa. The protective role of these chelating proteins is discussed.
Relationship Between Spatial Pattern of Basal Bodies and Membrane Skeleton (Epiplasm) During the Cell Cycle of Tetrahymena: cdaA Mutant and Anti‐Membrane Skeleton Immunostaining
Authors: KACZANOWSKA JANINA , BUZANSKA LEONORA , OSTROWSKI MAREK
Published: May 2007

Microtubular basal bodies and epiplasm (membrane skeleton) are the main components of the cortical skeleton of Tetrahymena. The aim of this report was to study functional interactions of basal bodies and epiplasm during the cell cycle. The cortex of Tetrahymena cells was stained with anti‐epiplasm antibody. This staining produced a bright epiplasmic layer with a dark pattern of unstained microtubular structures. The fluorescence of the anti‐epiplasm antibody disappeared at sites of newly formed microtubular structures, so the new basal body domains and epiplasmic layer could be followed throughout the cell cycle.

Different patterns of deployment of new basal bodies were observed in early and advanced dividers. In advanced dividers the fluorescence of the epiplasmic layer diminished locally within the forming fission line where the polymerization of new basal bodies largely extincted. In wild type Tetrahymena, the completion of the micronuclear metaphase/anaphase transition was associated with a transition from the pattern of new basal body deployment and epiplasm staining of the early divider to the pattern of the advanced dividers. The signal for the fission line formation in Tetrahymena (absent in cdaA1 Tetrahymena mutationally arrested in cytokinesis) brings about 1) transition of patterns of deployment of basal bodies and epiplasmic layer on both sides of the fission line; and 2) coordination of cortical divisional morphogenesis with the micronuclear mitotic cycle.
Directed Positioning of Micronuclei in Paramecium tetraurelia with Laser Tweezers: Absence of Detectible Damage After Manipulation
Authors: AUFDERHEIDE KARL J. , DU QING , FRY EDWARD S.
Published: May 2007

Possible covert damage from the use of the laser optical force trap (laser tweezers) to reposition micronuclei in Paramecium tetraurelia was assessed by measuring proliferation rates and postautogamous survival and mutation rates of cells after laser manipulations. No differences in subsequent daily proliferation rates among laser manipulated and various control classes of cells were seen. Similarly, the rates of postautogamous lethality and of “slow growth mutations” after repositioning of both micronuclei were not different from such rates in unmanipulated controls. In spite of extensive manipulations of micronuclei by the laser tweezers, there is no evidence of any damage induced by these manipulations. The laser tweezers therefore appears to be a tool of benign effect upon living cells, with tremendous potential use in many cell and developmental biological investigations.
Aminotransferase and the Production of Alanine During Hyperosmotic Stress in Paramecium calkinsi
Authors: CRONKITE DONALD L. , DIEKMAN ALAN B. , LEWALLEN BETH , PHILLIPS LISA
Published: May 2007

When Paramecium calkinsi encounter hyperosmotic stress, intracellular free alanine increases. In vivo assays indicate that the reaction catalyzed by alanine aminotransferase contributes to the build up of alanine in response to hyperosmotic shock. 14C‐pyruvate is converted to 14C‐alanine in cells grown axenically at 200 mosm. When shifted to 600 mosm, the rate of conversion of pyruvate to alanine increases, and conversion at either 200 or 600 mosm is blocked by 1 mM aminooxyacetic acid (AOA), an inhibitor of aminotransferase. Intracellular free alanine increase is partially inhibited by AOA, and AOA prevents cells living in fresh water from acclimating to higher salinities, an indication that the increase in intracellular alanine is physiologically significant.
Characterization of Pneumocystis carinii Preparations Developed for Lipid Analysis
Authors: KANESHIRO EDNA S. , WYDER MICHAEL A. , ZHOU LINDA HUA , ELLIS JAYNE E. , VOELKER DENNIS R. , LANGRETH SUSAN G.
Published: May 2007

Pneumocystis carinii organisms were isolated from viral antibody‐negative rats that had been infected by intratracheal intubation of organism preparations tested negative for common bacteria and fungi. Infection scores of lungs from infected animals at the time of parasite isolation was > 5 (100‐1,000 organisms/oil immersion field). Electron microscopy of heavily infected lungs revealed that the pathogens adhered to Type I pneumocytes and to each other, resulting in obstructions up to several cell layers thick, which extended into the alveolar lumen. Protocols for purifying the organisms were developed to optimize separation from each other and from host cells, and to optimize preparation purity, recovery efficiency, and organism viability. The study tested mucolytic agents, sieving, various centrifugation speeds, lysis of host cells by osmotic shock and filtration through membranes of different pore diameter. Final preparations contained no intact host cells as determined by light microscopy. Only minor amounts (< 5%) of host debris were detected by electron microscopy. Most organisms and their pellicles were ultrastructurally intact but no longer adhered to one another. The final preparation was characterized biochemically by quantitation of the specific lung surfactant marker surfactant protein A, which indicated > 99.5% purity. The total non‐P. carinii protein in the final preparation (< 6%, depending on the level of infection) was estimated by the protein content of pelletable material resulting from processing uninfected lungs in an identical manner. Elimination of free cholesterol and phospholipids from host lung tissue was monitored during the purification process. Exogenous stigmasterol, added as an extracellular marker, decreased during the purification process and was undetectable in the final organism preparation. Yields of 108‐109 organisms/rat were routinely obtained. Viability, assessed by the calcein acetoxymethyl ester‐propidium iodide assay, was 80–95%.
Genes Encoding Antigenic Surface Glycoproteins in Pneumocystis from Humans
Authors: STRINGER SAUNDRA L. , GARBE THOMAS , SUNKIN SUSAN M. , STRINGER JAMES R.
Published: May 2007

Pneumocystis is a eukaryotic microbe that causes pneumocystosis, an AIDS‐associated pneumonia. Pneumocystosis also occurs in many other mammalian species, and animal‐derived organisms have been extensively utilized in Pneumocystis research. Pneumocystis from diverse hosts contain a large glycoprotein (gpA/MSG) on the surface. Antibodies elicited against gpA/MSG of Pneumocystis from humans sometimes cross‐react with epitopes on proteins of similar size from Pneumocystis from other host species. Here we report the isolation and partial sequence of two presumptive gpA/MSG genes from human‐derived Pneumocystis. The cloned human‐derived Pneumocystis gpA/MSG genes and predicted peptides were different from those previously isolated from Pneumocystis from rats and ferrets. The genome of human‐derived Pneumocystis contained multiple copies of sequences related to the two cloned gpA/MSG genes.
The Golgi Apparatus of Tetrahymena Thermophila
Authors: KURZ SABINE , TIEDTKE ARNO
Published: May 2007

ABSTRACT. Electron microsocpic investigations reveal that the Golgi apparatus of Tetrahymena thermophila consists of numerous tiny dictyosomes, each consisting of one or two cisternae. the dictyosomes are localized predominantly in the cell cortex closely associated with the mitochondria, arranged in meridians alternating with the ciliary meridians. We estimated about 300‐400 of these dictyosomes in the periphery of a cell, a value corresponding to the number of somatic cilia per cell. Cytochemical assays of thiamine pyrophosphatase and acid phosphatase, both marker enzymes of trans Golgi cisternae, resulted in deposits of lead or cerium phosphate in the outermost cisternae of the dictyosomes. In addition, cisternae located at the bases of the basal body/parasomal sac arrangements are stained. This indicates that these cisternae may belong to the Golgi apparatus of the cell.
Immunological Detection of Cytoskeletal Proteins In the Exoerythrocytic Stages of Malaria By Fluorescence and Confocal Laser Scanning Microscopy
Authors: SUHRBIER ANDREAS , SINDEN ROBERT E. , COUCHMAN ANNA , FLECK SUZANNE L. , KUMAR SANJEEV , MCMILLAN DUNCAN
Published: May 2007

ABSTRACT. Using monospecific antibodies, the presence and distribution of tubulin, actin, myosin, intermediate filaments, and lamins were examined in the exoerythrocytic liver schizont of Plasmodium berghei by conventional indirect fluorescent antibody methods and confocal laser scanning microscopy. the binding reactivity of the antibodies to parasite proteins was determined by Western blot analysis. the localisation of all antibodies in control host hepatocytes followed expected distributions in both uninfected and infected hepatocytes; by contrast, reactivity to the exoerythrocytic schizont was variable. the parasite reacted positively with selected anti‐tubulin, ‐actin, and ‐myosin antibodies in both fluorescence and Western blot analysis. Anti‐lamin antibodies were positive by confocal indirect fluorescent antibody labelling, but no labelling was detected with anti‐intermediate filament antibody. Within the technical limits of resolution of the methods as applied to asynchronous parasite infections, not one of the antibodies reacting positively with the parasite by the indirect fluorescent antibody technique could be shown to identify unequivocally the classic architectural features associated with their respective target organelles, i.e. microtubules, stress‐fibres or the nuclear envelope.
Fine Structure Observations of Phagotrophic Activity By Plasmodia of Physarum Polycephalum
Authors: ANDERSON O. ROGER
Published: May 2007

ABSTRACT. Scanning electron microscopic observations of feeding plasmodia show three characteristic features: 1) extension of multilobed pseudopodia protruding from the leading edge of the plasmodium as it advances onto the surface of a food particle, 2) confluence of the lobes to form a sheath‐like pseudopodium attached to the surface of the food particle, and 3) protrusion of small nodules with thin lamellar projections from the leading edge of the plasmodium. Sections through freeze‐dried preparations of the feeding plasmodium exhibit a highly convoluted under surface in contact with loosened starch grains that appear to be released by extracellular digestion. the cytoplasm, viewed by transmission electron microscopy, contains branched, internally penetrating canals (ca. 2 μm wide) enclosing engulfed starch grains. Starch grains in the deeper part of the canals are more electron dense and appear to be digested. Micropseudopodia (70‐80 nm dia.), projecting from the surface of the canals, protrude toward and into the ingested starch grains. Digestive marker enzyme (acid phosphatase) activity was detected cytochemically in food particles penetrated by micropseu‐dopodia indicating a digestive role for these structures not reported previously.
Light and Electron Microscope Observations On Presporogonic and Sporogonic Stages of Sphaerospora Epinepheli (Myxosporea) In Grouper (Epinephelus Malabaricus)
Authors: SUPAMATTAYA KIDCHAKAN , FISCHER‐SCHERL THERESIA , HOFFMANN RUDOLF W. , BOONYARATPALIN SIDTHI
Published: May 2007

ABSTRACT. Presporogonic (blood) stages of Sphaerospora epinepheli Supamattaya, Fischer‐Scherl. Hoffmann, Boonyaratpalin, 1990 were observed in the circulating blood, sinus of kidney, glomerurar capillaries and liver arteries of grouper Epinephelus malabaricus. the earliest detectable stage was a primary cell with one secondary cell. After cell divisions, nine to 16 secondary cells were found in one primary cell. Ultrastructural examination revealed electron‐dense bodies (118‐145 nm) in the cytoplasm of primary cells. Sporogonic stages and spores were located in Bowman's space and in kidney tubule lumens. Electron micrographs revealed a similar pattern of spore development as described from other Sphaerospora spp. Kidneys infected with S. epinepheli showed highly vacuolated tubular epithelial cells and severely affected renal corpuscles.
Immunological Characterization of Trichocyst Proteins In the Ciliate Pseudomicrothorax Dubius
Authors: EPERON SIMONE , VIGUÈS BERNARD , PECK ROBERT K.
Published: May 2007

ABSTRACT. Ejectable trichocysts were isolated from the ciliate Pseudomicrothorax dubius. Polyclonal antibodies were raised against three groups of trichocyst proteins: G1 (30‐31 kDa), G2 (26‐27 kDa) and G3 (15‐20 kDa). By indirect immunofluorescence, the three antisera strongly label the shafts of ejected trichocysts and the proximal ends of condensed trichocysts within the cells. By immunogold labeling for electron microscopy, the three sera specifically recognize the shafts of both extended and condensed trichocysts and shaft precursors in pretrichocysts as well. On one‐dimensional immunoblots of isolated trichocysts, anti‐G1 serum recognizes the G1 proteins, anti‐G2 serum detects G2 proteins and some G1 proteins, and anti‐G3 serum reacts with 15 bands, mainly the G3 and (30‐41)‐kDa proteins. In cells with and without trichocysts, the sera recognize non‐ejectable trichocyst proteins at 41‐42 kDa and 47 kDa. On two‐dimensional immunoblots of isolated trichocysts, anti‐G1 serum labels proteins with a pI of 4.75‐5.7, anti‐G2 serum labels proteins with a pI of 4.75‐6.25 and anti‐G3 serum labels proteins with a pI of 4.7‐6.6. Analyses of cells with and without trichocysts allow identification of possible precursors between 41 and 47 kDa. Some are in the same pI range as their putative products, but others, labeled by anti‐G3 serum, are less acidic than most of their mature products.
Evidence For the Presence of A Cdc2‐Like Protein Kinase In the Dinoflagellate Crypthecodinium Cohnii
Authors: RODRIGUEZ MARIVONNE , CHO JEONG W. , SAUER HELMUT W. , RIZZO PETER J.
Published: May 2007

ABSTRACT. The unusual nature of mitosis and ancestral organization of the dinoflagellate nucleus prompted the question of whether the cdc2‐like histone H1 kinase, a presumed ubiquitous cell cycle regulator in eukaryotes, is present in these primitive organisms. Western blotting of Crypthecodinium cohnii protein extracts using antibody against the Pro‐Ser‐Thr‐Ala‐Ile‐Arg‐Glu (=PSTAIRE) amino acid sequence motif, conserved in all cdc2 homologues known, revealed one prominent band corresponding to a protein with an apparent relative molecular weight ≈ 34,000, identical in mobility to that from HeLa cells and Physarum polycephalum, higher and lower eukaryotic controls, respectively. Incubation of C. cohnii cell lysates with p13suc1‐sepharose beads, which preferentially, though not exclusively, bind p34cdc2, resulted in precipitation of a 34‐kDa protein which was reactive with anti‐PSTAIRE antibody, selectively competed for by the PSTAIRE peptide and able to phosphorylate histone H1 in vitro. We conclude that the dinoflagellate C. cohnii contains a protein very similar to the cdc2 gene product from fission yeast and its homologues in all eukaryotes studied thus far.
Light and Electron Microscope Study of Urosporidium cannoni N. Sp., a Haplosporidian Parasite of the Polyclad Turbellarian Stylochus sp.
Authors: ANDERSON TIMOTHY J. , NEWMAN LESLIE J. , LESTER ROBERT J. G.
Published: May 2007

ABSTRACT. Urosporidium cannoni n. sp. was found in most tissues of a polyclad turbellarian associated with commercial oyster farms from eastern Moreton Bay, Australia. Mature spores had 11 to 13 episporal tails at irregular intervals around the spore wall. The spherule, prominent in development, dispersed as the spores matured. Spores were found within cysts that contained up to a few hundred spores at the same stage of development. Mature cysts occurred in groups and their masses of dark, golden spores resulted in black patches on the otherwise red‐brown turbellarian. The infection may have commercial importance.
Oxygen Uptake In Cysts and Trophozoites of Giardia Lamblia
Authors: PAGET TIMOTHY A. , MANNING PAUL , JARROLL EDWARD L.
Published: May 2007

ABSTRACT. Oxygen uptake in cysts and trophozoites of the parasitic protozoan Giardia lamblia was examined. Both showed oxygen uptake activity, but that of cysts was only 10% to 20% that of trophozoites. Oxygen dependence of oxygen uptake in cysts and trophozoites showed oxygen maxima above which oxygen uptake decreased. the oxygen concentration at which the oxygen uptake rate was greatest was higher for trophozoites than for cysts. the effect of various inhibitors on cyst and trophozoithe oxygen uptake suggested that flavoproteins and quinones play some role in oxygen uptake. the substrate specificities and the effect of inhibitors on G. lamblia trophozoites were similar to those observed for G. muris. Metronidazole, the drug most commonly used in treatment of giardiasis, inhibited oxygen uptake and motility in trophozoites; however, it had no obvious effect on either oxygen uptake or excystation in cysts. Menadione, a redox cycling naphthaquinone, first stimulated, then completely inhibited, oxygen uptake in cysts and trophozoites; a complete loss of cyst viability and trophozoite motility was also observed. the effect of menadione on G. Iamblia may indicate that redox cycling compounds have potential as chemotherapeutic agents for the treatment of giardiasis.
Gametogenesis and Sporogony of Hepatozoon Mocassini (Apicomplexa: Adeleina: Hepatozoidae) In an Experimental Mosquito Host, Aedes Aegypti
Authors: LOWICHIK AMY , LANNERS H. NORBERT , LOWRIE ROBERT C. , MEINERS NORWOOD E.
Published: May 2007

ABSTRACT. The sexual life cycle of the hemogregarine Hepatozoon mocassini was studied in Aedes aegypti, an experimental mosquito host, using transmission electron microscopy. Gamonts were observed leaving the host snake erythrocyte as early as 30 min after mosquitoes ingested infected blood, and some gamonts had penetrated the gut epithelial cells by this time. Six hours post‐feeding, gamonts were identified within cells of the abdominal fat body. Twenty‐four hours post‐feeding, gamonts were often entrapped within the peritrophic membrane, but were no longer observed within the gut wall. Parasites pairing up in syzygy and undergoing sexual differentiatioe were observed within fat cells at this time, and by 48 hours post‐feeding, well‐developed macro‐ and microgametocytes as well as microgametes were discernible. Developing zygotes observed 3 days post‐feeding were enclosed within a panoitophorous vacuole. By day 6, multinucleate oocysts with crystalloid bodies in the cytoplasm were seen. Sporazoites developing within sporocysts appeared by day 12. Seventeen days post‐feeding, mature oocysts with sporocysts containing approximately 16 sporozoites were observed upon dissection of mosquitoes. Large crystalloid bodies no longer bound by rough endopbsmic reticulum were located anterior and posterior to the sporozoite nucleus. Free sporozoites were not observed.
Disruption of Ca2+ Homeostasis In Trypanosoma Cruzi By Crystal Violet
Authors: DOCAMPOA ROBERTO , GADELHA FERNANDA R. , MORENO SILVIA N. J. , BENAIM GUSTAVO , HOFFMANN MARIA E. , VERCESI ANIBAL E.
Published: May 2007

ABSTRACT. We have demonstrated previously that crystal violet induces a rapid, dose‐related collapse of the inner mitochondrial membrane potential of Trypanosoma cruzi epimastigotes. In this work, we show that crystal violet‐induced dissipation of the membrane potential was accompanied by an efflux of Ca2+ from the mitochondria. In addition, crystal violet inhibited the ATP‐dependent, oligomycin‐, and antimycin A‐insensitive Ca2+ uptake by digitonin‐permeabilired epimastigotes. Crystal violet also induced Ca2+ release from the mitochondria and endoplasmic reticulum of digitonin‐permeabilized trypomastigotes. Furthermore, crystal violet inhibited Ca2+ uptake and the (Ca2+‐Mg2+)ATPase of a highly enriched plasma membrane fraction of epimastigotes, thus indicating an inhibition of other calcium transport mechanisms of the cells. Disruption of Ca2+ homeostasis by crystal violet may be a key process leading to trypanosome cell injury by this drug.
The Kinetics of Fatty Acid Uptake By Paramecium Tetraurelia
Authors: REUTER STEVEN F. , PRAIRIE RICHARD L. , KANESHIRO EDNA S.
Published: May 2007

ABSTRACT. The kinetics of radiolabeled fatty acid uptake by the ciliate Paramecium tetraurelia was examined on a homologous series of saturated, straight chain fatty acids of even carbon numbers. Uptake rates increased with chain length from acetate to palmitate. Saturation kinetics was demonstrated for most fatty acids examined, thus ruling out simple diffusion as the major mechanism for fatty acid transport and implicating carrier‐mediated, facilitated transport as the major mechanism. Data from most competitive inhibition experiments were too scattered to determine the number of transporter systems present. Cholesterol uptake also exhibited saturation kinetics and hence other sterols, which can satisfy this nutritional requirement, may also be transported by a carrier‐mediated mechanism. the uptake of the essential fatty acid oleate was faster than those observed for the saturated acids and could not be explained by only one transport mechanism. Therefore, fatty acid transport also occurs via other kinetically significant routes.
Ultrastructure of Prorodon (Ciliophora, Prostomatida) I. Somatic Cortex and Some Implications Concerning Kinetid Evolution In Prostomatid and Colpodid Ciliates
Authors: HILLER STEPHAN A.
Published: May 2007

ABSTRACT. This study describes the ultrastructure of the somatic cortex of Prorodon aklitolophon and Prorodon teres. the meridionally arranged somatic kineties of both species can be separated into two parts: a short anterior part, which consists of a few somatic dikinetids (in which both kinetosomes are ciliated), and a longer posterior consisting of monokinetids. the somatic monokinetids are associated with a convergent postciliary microtubular ribbon, a transverse microtubular ribbon flatly inserted in front of the kinetosome, a short and steeply extending kinetodesmal fibre attached to kinetosomal triplet 5 and 7, and a desmose anterior to triplet 3. From this desmose, two to five prekinetosomal microtubules originate and extend anteriorly. the posterior kinetosome of the somatic dikinetids is associated with the same microfibrillar and microtubular structures as the somatic monokinetid, except that no prekinetosomal microtubules originate from the desmose. the anterior kinetosome has a single postciliary microtubule and a tangentially oriented transverse microtubular ribbon. the permanent collecting canals of the unique contractile vacuole system extend parallel and adjacent to the somatic kinetics of Prorodon. the collecting canals are supported by the prekinetosomal microtubules. A similarly organized contractile vacuole system is not yet known from any other ciliate group. One of the most surprising results of this investigation was finding a significant similarity between the somatic dikinetid pattern of Prorodon and the colpodid dikinetid pattern. A hypothesis is presented to illustrate the evolution of the somatic kinetid patterns in colpodid and prostomatid ciliates.