bluuebunny/crossref_metadata_2025 huggingface dataset:
Fine Structure and Biomineralization of the Mucilage in Envelopes ofTrachelomonas lefevrei(Euglenophyceae)1
Authors: DUNLAP JOHN R. , WALNE PATRICIA L.
Published: May 2007

Envelope development inTrachelomonas lefevrei(Deflandre) begins with the production of short, coarse mucilaginous strands, morphologically similar to the mucilage produced by non‐enveloped euglenoids. These initial mucilaginous secretions subsequently become impregnated with manganese (Mn) and/or iron (Fe). Continued mucilage secretion and mineralization results in a mature envelope that is characteristic for the species. When these mature envelopes are treated with oxalic acid to remove the Mn and Fe, the envelopes collapse and are composed only of short, coarse mucilaginous strands similar to those present during early stages of development, prior to their mineralization. Brief treatment with 10 mM EDTA renders dark envelopes colorless, and our EM‐EDS analyses show that this corresponds to a loss of Mn from the envelope; however, if Fe is present in the envelope, it is unaffected by the brief treatment. The mucilage present during early stages of envelope development and that remaining after complete demineralization is also morphologically similar to the mucilage in the plug at the anterior end of the envelope.
Morphogenesis in the Heterotrich Ciliate Climacostomum virens. II. Oral Development During Regeneration1
Authors: FAHRNI JOSÉ F.
Published: May 2007

The regeneration (RG) of the oral apparatus (OA) by Climacostomum virens (Ciliophora, Heterotrichida) is examined by estimation of the ability of live cells to ingest food as well as by Nomarski interference contrast microscopy, bright field microscopy of protargol‐stained specimens, and by scanning electron microscopy. When placed in a 6% (w/v) urea solution for ∼ 2 min 10 sec, populations of 10,000–100,000 cells shed a large part of their OA. In more than 90% of the cells that shed, the discarded segment is comprised of the apical membranelles, most of the adoral membranelles, and of a variable part of the buccal tube. After washing and incubation at 26°C, 50% of the cells regenerate a functional OA in 4 h 47 min, and after 5 h 26 min, 90% of the cells are able to ingest food. At any given moment during the process, 50–90% of the cells are morphologically in the same stage of RG.

Seven stages (among which three are divided into two substages) of RG are defined. The process begins by the disorganization of the remnant oral structures. Concomitantly, kinetosomes multiply along the kineties of the zone of discontinuity and form the longitudinally oriented oral primordium. The latter gives rise to the adoral primordium, which rapidly produces the adoral zone of membranelles (AZM), and to the paroral primordium, which subsequently forms the apical membranelles, the buccal peristomial kineties, and the paroral kinety. Morphogenetic movements lead to incurvation of the AZM and the frontal field and to invagination of the buccal tube.
Starved Tetrahymena Synthesize and Maintain an Excess of 5s rRNA in Their Cytoplasm1
Authors: LIBBY STEPHEN J. , HALLBERG RICHARD L.
Published: May 2007

We have measured the rate of accumulation of newly synthesized 5s ribosomal RNA (5s rRNA) in Tetrahymena thermophila cells in early log phase growth and in cells that had been starved in a dilute salt solution. From these measurements we have determined the rates of synthesis and levels of accumulation of 5s rRNA relative to 5.8s rRNA in these two different cell populations. In growing cells 5s rRNA is transcribed and accumulated in a 1:1 molar ratio when compared with 5.8s rRNA. In contrast, in starved cells, 5s rRNA is produced at a rate which is about 15% higher than that seen for 5.8s rRNA. This excess 5s rRNA accumulates in the cytoplasm in a non‐ribosomal form and is maintained in the cell as long as the cell remains in a starved condition. The role this excess 5s rRNA may play in the control of 5s rRNA gene expression is discussed.
Coccidia (Eimeria tachyglossi n. sp., E. echidnae n. sp., and Octosporella hystrix n. sp.) in the Echidna, Tachyglossus aculeatus (Monotremata: Tachyglossidae)
Authors: BARKER IAN K. , BEVERIDGE IAN , MUNDAY BARRY L.
Published: May 2007

Oocysts of Octosporella hystrix n. sp., Eimeria tachyglossi n. sp., and E. echidnae n. sp. are described from the feces of the echidna Tachyglossus aculeatus (Monotremata: Tachyglossidae) from Australia. Eimeria tachyglossi has subspherical oocysts, 26.4 × 23.7 μm in size, with a single oocyst wall; no micropyle; four ellipsoidal sporocysts 13.2 × 9.7, slightly pointed at one end, each containing two sporozoites. Eimeria echidnae has subspherical oocysts, 19.4 × 17.8 in size, with a single oocyst wall; no micropyle; four ellipsoidal sporocysts 9.8 × 7.8, blunt at both ends, each containing two sporozoites. Octosporella hystrix has ovoid or subspherical oocysts 32.9 × 29.7 in size with a thick outer and thin inner oocyst wall; no micropyle; eight sporocysts spherical or slightly subspherical 11.3 × 11.2 each containing two sporozoites lying in embrace, with an extensive granular sporocyst residuum about the equator of the sporocyst. Endogenous stages considered to be of E. tachyglossi at least, were recognized in the lamina propria and epithelium on villi in the small intestine of three echidnas.
Macrophage Activation by Tetrahymena pyriformis II. Active Protein Fractions from Tetrahymena
Authors: MAKIOKA ASAO , KOBAYASHI AKIO
Published: May 2007

ABSTRACT. Water‐soluble and 0.6 M KCl‐soluble protein fractions prepared from Tetrahymena pyriformis, when inoculated into mice, could effectively induce activated macrophages having the ability to kill Toxoplasma gondii in vitro. This effect was not induced by other proteins tested, such as bovine serum albumin, pepsin from porcine stomach mucosa and chicken egg‐white lysozyme, nor by muramyl dipeptide (MDP), a potent immunoadjuvant. Five fractions obtained by DEAE‐Sephadex chromatography of the water‐soluble protein fraction were compared with regard to induction of toxoplasmacidal activity in macrophages. The first peak was most effective for activation of macrophages. Five fractions obtained by chromatography of the 0.6 M KCl‐soluble protein fraction were also examined and it was found that the first peak had the activity. No marked difference in activity was observed between the active fractions of water‐soluble and 0.6 M KCl‐soluble protein fractions. For practical use, we focused on the water‐soluble active fraction. The minimum effective dose of the active fraction was 100 μg and the fraction could activate macrophages directly in vitro. Four fractions obtained by gel filtration of the active fraction on Sephadex G‐200 were compared and the first peak had the activity. The first peak contained a single protein, revealed by SDS‐polyacrylamide gel electrophoresis; its apparent molecular weight was 64,000.
The Effect of Grazing by a Ciliated Protozoan on Phosphorus Limitation of Heterotrophic Bacteria in Batch Culture1
Authors: TAYLOR WILLIAM D.
Published: May 2007

ABSTRACT. The yield of the bacterium Enterobacter aerogenes and the ciliate Colpidium colpoda was dependent on initial phosphorus concentrations in batch cultures containing 125 or 250 mg/liter glutamate and 50–1000 μg/liter phosphorus. For both, yield per unit phosphorus declined at higher phosphorus concentrations. A marked decline in growth rate in bacterial cultures was coincident with the depletion of dissolved phosphorus and the development of rapid orthophosphate turnover times. Colpidium introduced to these cultures consumed about 16,000 bacteria/h/ciliate while multiplying exponentially and relieved phosphorus limitation, as indicated by a longer turnover‐time for phosphate. The longer turnover‐time was due to the reduction of bacterial numbers; in cultures with ciliates, bacteria appear to be more active in taking up phosphate, and much of the total phosphorus accumulates in ciliates. Ciliates released both inorganic and organic phosphorus, but the organic phosphorus did not accumulate to excess in the cultures to an extent that would indicate that it is less used by bacteria. Although ciliates release enough phosphorus to account for ca. 20% of the bacterial uptake, ciliates appear to behave as phosphorus sinks as much as phosphorus recyclers in these closed systems.
Relations Between Photobehavior and Ionically Stimulated Swimming Behavior in Paramecium bursaria1
Authors: CRONKITE DONALD L.
Published: May 2007

ABSTRACT. Cells of Paramecium bursaria, which harbor a symbiotic alga of the genus Chlorella, reverse the effective beat of their cilia and swim backward when stimulated in either of two ways. Ionic stimulation is introduction of cells into a solution high in K+ while step‐down photostimulation is a sharp reduction in the intensity of light falling on the culture. Much is known about the mechanisms of ionic stimulation of ciliary reversal, but little is known about step‐down photobehavior. Inhibitors of ionically stimulated ciliary reversal were applied to cells undergoing step‐down photobehavior; Ca‐channel inhibitors, neomycin and W‐7, inhibit both behaviors. Activation of Ca‐channels in the ciliary membrane is involved in step‐down photobehavior, suggesting that the algae may alter the Paramecium membrane to make it more excitable.
In Vitro Production of Metacyclic Forms of Trypanosoma musculi and Their Infectivity in CBA Mice1
Authors: ROGER MICHEL , VIENS PIERRE
Published: May 2007

ABSTRACT. Bloodstream forms of Trypanosoma musculi, cultured in Schneider's drosophila medium at room temperature, multiply and differentiate through a series of developmental stages into infective metacyclic trypomastigotes in 10 days. Oral inoculation with these culture forms into CBA mice produced a parasitemia similar to that produced by intraperitoneal infection with bloodstream forms except for a three‐day longer prepatent period. Attempts to induce parasitemia with bloodstream forms given orally were unsuccessful.
Multivariate Analysis of Protist Communities in Lentic Systems1
Authors: STEWART PAUL M. , SMITH ERIC P. , PRATT JAMES R. , McCORMICK PAUL V. , CAIRNS JOHN
Published: May 2007

ABSTRACT.The purpose of this research was to examine the roles of physico‐chemical parameters in structuring protist communities that colonize artificial substrates. Polyurethane foam (PF) substrates were placed in five lentic systems in northern lower Michigan during summer 1983. These lentic habitats represented a range of trophic states and included three lakes, a bog, and a marsh. Triplicate PF substrates were sampled after 1, 3, 7, 14, 21, and 42 days of exposure. During this study, 90 living protist samples were examined for the number and kinds of species. Water samples were analyzed for pH, conductivity, alkalinity, chloride, silica, temperature, dissolved oxygen, ammonia, and total and ortho‐phosphate concurrent with artificial substrate collections. A total of 546 protist species was recorded. Only seven species were found in over 50% of the samples and 121 species were found in only one sample. The 96 most common species were examined in relation to environmental parameters using several multivariate statistical procedures. Factor analysis (principal components with varimax rotation) performed on the total environmental data set showed that three composite factors explained 85% of the variability of the data set. A reciprocal averaging ordination (RAO) was used to reduce species presence/absence data and to separate samples graphically by their species composition. Significant correlations, with RAO‐generated axes from all five systems, were found for pH, oxygen, and a nutrient factor to axis 1. Factor analysis on the physico‐chemical parameters of the three lakes showed that three factors explained 71% of the environmental data set variability. The RAO‐generated axis (axis 1) was correlated with silica, ortho‐phosphate, and Factor 2, which was primarily comprised of loadings from ortho‐phosphate. These techniques support the hypothesis that a limited number of environmental parameters strongly affect protist community composition.
Isoenzyme Analysis of Babesia microti Infections in Humans
Authors: MOSS DELYNN M. , HEALY GEORGE R. , DICKERSON JENNIFER W. , MATHEWS HENRY M.
Published: May 2007

ABSTRACT. We used high‐resolution polyacrylamide gradient gel electrophoresis (PGGE) to separate four babesial enzymes to aid in the identification of two Babesia microti isolates established in hamsters. The isolates were compared to two different hamster passages of the “Gray” strain. All isoenzyme patterns from the two isolates and the “Gray” strain were similar except glucose phosphate isomerase (GPI) from one of the “Gray” strain passages. It showed a polymorphic GPI pattern as opposed to a monomorphic GPI pattern seen in the other “Gray” strain passage and the two isolates. The observed differences suggested (i) that some populations of B. microti are capable of having polymorphic GPI, (ii) that the “Gray” strain originally contained (and may still contain) a heterogenous population of B. microti, and (iii) that the population possessing polymorphic GPI was selected over that with monomorphic GPI. This information was obtained by a PGGE method that eliminated hemoglobin from gels and allowed, for the first time, detection of babesial leucine amino peptidase (LAP) and isocitrate dehydrogenase (IDH). In addition, this method provided molecular weight estimations on babesial GPI, LAP, IDH, and glutamate dehydrogenase (GDH), and it proved useful in the identification and characterization of the B. microti isolates.
Suitability of Selected Bacteria and Yeasts for Growing the Estuarine Heterotrich Ciliate Fabrea salina (Henneguy)1
Authors: REPAK ARTHUR J.
Published: May 2007

ABSTRACT. Twenty‐six species of bacteria and seven species of yeasts were aseptically presented separately as potential food sources to the estuarine heterotrich ciliate, Fabrea salina, under standardized conditions of cell number, medium, and temperature. The bacteria and yeasts were classified according to their effect on the intrinsic growth rate of the ciliate: Nutritious bacteria: Photobacterium fisherii, Vibrio neresis, V. natriegens, Flavobacterium sp. strain ASN16, V. harveyi, Xanthomonas sp. strain ASN22; Maintainer bacteria: V. vulnificus, Vibrio sp. strain V344, V. alginolyticus, V. anguillarum, Bacillus sp. strain ST332B2, Vibrio sp. strain V415, Acinetobacter sp. strain BHT8, Flectobacillus marinus, and Enterobacter aerogenes; Maintainer yeasts: Candida albicans and Cryptococcus marcerans strain 2; Nonnutriuous bacteria: V. parahaemolyticus, Planococcus sp. strain ASN13, P. mandapapanensis, Hyphomicrobium vulgari, Pseudomonas sp. strain CNS1, an unidentified gram‐negative, yellow‐pigmented, motile bacillus strain IG9A2, Thiobacillus thioparus, Escherichia coli, Corynebacterium sp. strain BR 17, Achromobacter sp. strain 23030, and Oceanospirillum beijerinckii; Nonnutriuous yeasts: C. marcerans strain 1, Saccharomyces cerevisiae, Debaryomyces hansenii, an unidentified black yeast, and C. laurentii. Under the conditions specified, bacteria appear to have a certain minimal value for the growth of Fabrea while yeast have little to none.
Infectivity of Trypanosoma rhodesiense Cultivated at 28°C with Various Tsetse Fly Tissues1
Authors: CUNNINGHAM ISABEL
Published: May 2007

ABSTRACT. Metacyclic trypanosomes developed in populations of procyclic forms of four stocks of Trypanosoma brucei rhodesiense cultivated at 28°C in a liquid medium containing explants of tsetse fly head‐salivary glands, alimentary tract, abdominal body wall, or thoracic muscle. The cultures became infective for mice 7–16 days after they were prepared, and infective trypanosomes were present for prolonged periods. In the culture series of stock TRUM 545, infectivity persisted for 138 days when the cultures were terminated. Only one explant of thoracic muscle tissue was required for the production of metacyclic stages in stock TRUM 497 cultures. Infectivity titrations on trypanosome suspensions from cultures of stocks TRUM 497, TRUM 545, and TRUM 567 revealed that only a small proportion of the culture population was infective. Using stock TRUM 530, mice were infected consistently from inoculations of trypanosomes grown in the presence of explants; infectivity of the trypanosomes ceased when the explants were removed from the flasks, but reappeared when they were returned to the cultures. Parasites grown in medium “conditioned” by explants produced sporadic infections in mice. The control cultures of trypanosomes grown in medium alone were generally not infective, but two of the stocks produced occasional parasitemias. Stained samples of infective inocula contained a few epimastigote‐like and metacyclic‐like trypanosomes.
Coccidia (Apicomplexa: Eimeriidae) from Sciurid Rodents (Eutamias, Sciurus, Tamiasciurus spp.) from the Western United States and Northern Mexico with Descriptions of Two New Species1
Authors: HILL TODD P. , DUSZYNSKI DONALD W.
Published: May 2007

ABSTRACT. Since May 1979, 190 rodents in the family Sciuridae, representing three genera and nine species, have been collected in the western United States and northern Mexico and examined for coccidia; 71 (37%) had coccidian oocysts in their feces. These included 2 of 12 (17%) Eutamias canipes; 7 of 12 (58%) E. dorsalis; 18 of 50 (36%) E. merriami; 33 of 96 (34%) E. obscurus; 3 of 4 (75%) E. townsendii; 3 of 9 (33%) Sciurus aberti; 1 of 1 S. griseus; 1 of 1 Tamiasciurus hudsonicus mogollonensis; and 3 of 5 (60%) T. mearnsi. The following coccidians were identified from infected rodents: Eimeria cochisensis n. sp. and Eimeria dorsalis n. sp. from E. canipes; E. cochisensis, E. dorsalis, and E. tamiasciuri from E. dorsalis; E. dorsalis and E. tamiasciuri from E. merriami; E. cochisensis, E. dorsalis, E. tamiasciuri, and E. wisconsinensis from E. obscurus; E. cochisensis and E. dorsalis from E. townsendii; E. ontarioensis and E. tamiasciuri from S. aberti; E. tamiasciuri from S. griseus; E. tamiasciuri and E. toddi from T. h. mogollonensis; and E. tamiasciuri from T. mearnsi. Sporulated oocysts of Eimeria dorsalis n. sp. were ovoid, 21.9 × 16.8 (17–24 × 14–20) μm with sporocysts ovoid, 11.5 × 6.9 (10–14 × 6–8) μm. Sporulated oocysts of Eimeria cochisensis n. sp. were spheroid to subspheroid, 16.7 × 15.3 (15–18 × 14–17) μm, with sporocysts ovoid, 8.4 × 5.6 (6–11 × 4–7) μm. Fifty‐five of 71 (77%) infected hosts had oocysts of only one eimerian species in their feces at the time they were examined. One eimerian, E. tamiasciuri, was found in seven of nine host species in three genera. A list is provided of all eimerians (22, including the species described here) that have been described in the literature from Eutamias, Sciurus, and Tamiasciurus spp.
Pterospora schizosoma, a New Species of Aseptate Gregarine from the Coelom of Axiothella rubrocincta (Polychaeta, Maldanidae)1
Authors: LANDERS STEPHEN C. , GUNDERSON JOHN
Published: May 2007

ABSTRACT. An undescribed species of aseptate gregarine, for which the name Pterospora schizosoma is proposed, occurs in the coelom of the maldanid polychaete Axiothella rubrocincta (Johnson). The body of the mature gamont is divided into two cylindrical trunks, which are joined anteriorly. Posteriorly, each trunk bifurcates twice, thereby producing four terminal branches. The length of the entire organism varies from 230–600 μm. The organism actively pumps endoplasm from one trunk to the other, and the nucleus (average = 56.2 × 25.9 μm) moves with the flowing endoplasm. In all four of the previously described species, the gamont's main trunks arise from a substantial body mass whereas in P. schizosoma the trunks make up most of the body mass. Pterospora schizosoma's oocysts possess a distinct outer and inner capsule, which contains eight tightly appressed sporozoites.
Demonstration of Various Acid Hydrolases and Preliminary Characterization of Acid Phosphatase in Naegleria fowleri1
Authors: OLOMU NICHOLAS , MARTINEZ A. JULIO , LAMARCO KAREN L. , NERAD THOMAS A. , SAHA ASISH K. , DAS SIDDHARTHA , GLEW ROBERT H.
Published: May 2007

ABSTRACT. Extracts of the pathogenic ameba Naegleria fowleri, prepared by freeze‐thawing and sonication, were analyzed for their content of various hydrolytic enzymes that have acid pH optima. The organism is rich in acid phosphatase activity as well as a variety of glycosidases which include β‐glucosidase, β‐galactosidase, β‐fucosidase, α‐mannosidase, hexosaminidase, arylsulfatase A, and β‐glucuronidase. The crude extract contained only negligible levels of sphingomyelinase, neuraminidase, or arylsulfatase B. All of the hydrolases exhibited higher activity at pH 5.5 than at 7.0, indicating that they are truly “acid” hydrolases. In general, after centrifugation (100,000 g, 1 h), except for arylsulfatase B, more than half of the activity of each of the various hydrolases was recovered in the supernatant fraction. The acid phosphatase in the high‐speed supernatant was purified 45‐fold (32% yield) by chromatography on QAE‐Sephadex and Sephadex G‐200 and shown to have the following properties: 1) pH optima, 5.5; 2) Km (4‐methylumbelliferyl phosphate), 0.60 mM; 3) molecular weight (estimated by gel filtration chromatography), 92,000; 4) inhibited by heteropolymolybdate complexes but not by L(+) sodium tartrate (0.5 mM) or sodium fluoride (0.5 mM). In addition, unlike the tartrate‐resistant acid phosphatase of Leishmania donovani, the major acid phosphatase of N. fowleri is less than 5% as effective in inhibiting superoxide anion production by f‐Met‐Leu‐Phe‐stimulated human neutrophils. The finding of high levels of a number of acid hydrolases in Naegleria fowleri raises several questions that merit further study: Do the hydrolases perform a housekeeping function in this single cell eukaryote or do they play some role in the pathogenic process that ensues when the organism infects a suitable host?
Naegleria Actin Elicits Species‐Specific Antibodies1
Authors: FULTON CHANDLER , LAI ELAINE Y. , LAMOYI EDMUNDO , SUSSMAN DANIEL J.
Published: May 2007

ABSTRACT. Actin, the major protein of amebae of Naegleria gruberi, proved to be strongly immunogenic in rabbits. The resulting precipitating antibodies are specific to actin of Naegleria. In a competitive solid‐phase radioimmunoassay, these antibodies bound similarly to Naegleria G‐ and F‐actin. Actins from amebae of Acanthamoeba and Dictyostelium, plasmodia of Physarum, sea urchin eggs, and vertebrate muscles gave no competition in the radioimmunoassay. Estimates of the amount of actin in Naegleria amebae ranged from a minimum of 5% of the total cell protein by radioimmunoassay to a maximum of 16% by electrophoresis. The unusual species specificity of these antibodies indicates that Naegleria actin, although conserved in many properties, is different enough to have unique antigenic determinants.
Expression of Surface Coat Glycoconjugates by Bacteria‐Fed Tetrahymena1
Authors: BOLIVAR IGNACIO , GUIARD‐MAFFIA JACQUELINE
Published: May 2007

ABSTRACT. We have shown that bacteria‐fed Tetrahymena express at their surface and excrete into the medium a glycoconjugate absent in axenically grown cells. A preliminary analysis of the purified molecule is given. Immunolabeling of blotted surface extracts and fixed cells shows that bacteria‐fed Tetrahymena build up a surface coat whose material originates totally or in part in the mucocysts. The glycoconjugate is located externally on the coat and mediates cell immobilization and immunolabeling by the serum. The results also indicate that axenic cells are probably devoid of surface coat.
Seasonal Distribution of Thermotolerant Free‐Living Amoebae. I. Willard's Pond1
Authors: KYLE DENNIS E. , NOBLET GAYLE PITTMAN
Published: May 2007

ABSTRACT. A quantitative study of the seasonal distribution of thermotolerant (37°C and 45°C), small free‐living amoebae (FLA) was conducted in Willard's Pond, a warm, monomictic lake in the Piedmont region of South Carolina. Correlation of physical and chemical parameters with the seasonal distribution was facilitated by partitioning the aquatic ecosystem into benthic, planktonic, and neustonic habitats. Population densities of FLA peaked in late summer in each habitat; however, species composition varied between habitats. Littoral sediment appeared to be the major habitat for FLA, with peaks in populations of Acanthamoeba and Naegleria in August, Hartmannella in July, and Vahlkampfia in May. Populations in profundal sediment underwent dramatic seasonal shifts, apparently in response to the seasonal chemical changes in the hypolimnion. Acanthamoeba was most prevalent in late summer, representing as much as 82% of the FLA in profundal sediment. Distribution patterns and species composition of FLA from surface water were similar to those from littoral sediment; however, a greater percentage of Naegleria was found in surface water. Numerous FLA were isolated from the neustonic community (surface film), and the number of FLA isolated in the surface film at the deep water station was found to be significantly (P > 0.05) greater than the number from subsurface (5–10 cm) samples. In the water column, FLA populations consistently were highest in the detrital layer, which persisted at a depth of 3.0–3.4 m throughout the summer period. The large percentage of Naegleria contributing to FLA in the detrital layer suggests that Naegleria amoeboflagellates sink through the layer, flagellate, and swim back up, such migrations possibly being triggered by a reduction of nutrients below the layer or by the presence of anoxic, reducing conditions in the hypolimnion. In addition, weather events were found to play a major role in the redistribution of FLA between various habitats in the aquatic ecosystem, with such changes probably due to resuspension of FLA from littoral sediment by wind action and input from the watershed via runoff.
A Method for Long Term Laboratory Maintenance of Marine Psammophilic Ciliates
Authors: CAREY P. G.
Published: May 2007

ABSTRACT. There has been a distinct lack of morphological, physiological, and taxonomic studies on the marine psammophilic ciliates despite their importance in the benthic biotope. These fragile ciliates are considered a problematical group, most research being attempted under inconvenient conditions on the seashore or at adjacent sites. To alleviate this problem, an apparatus has been designed to maintain psammophilic ciliate communities for periods of up to six months in the laboratory, making them freely available for detailed cytological study.
Trypanosoma cruzi: Structure and Transcription of Kinetoplast DNA Maxicircles of Cloned Stocks12
Authors: AFFRANCHINO JOSE L. , SANCHEZ DANIEL O. , ENGEL JUAN C. , FRASCH ALBERTO C. C. , STOPPANI ANDRES O. M.
Published: May 2007

ABSTRACT. Restriction endonuclease mapping of the Trypanosoma cruzi kinetoplast DNA maxicircle was performed in nine cloned stocks using maxicircle probes from T. brucei. Analysis of the maxicircle 13–15‐kbp encoding region allowed cloned stocks to be divided into three groups: A, B, and C. Parasites from groups A and B had 3% sequence divergence while parasites from group C showed 16–17% sequence divergence with regard to parasites from groups A and B. Cross‐hybridization experiments demonstrated that the 23–25‐kbp maxicircle divergent region was similar in sequence in group A and B, but different in group C parasites. The high homology of the T. cruzi and T. brucei encoding regions allowed the use of T. brucei probes to detect T. cruzi transcripts, whose overall picture did not differ for parasites from any of the nine assayed clones.
Photosensitivity in the Ciliated Protozoon Loxodes: Pigment Granules, Absorption and Action Spectra, Blue Light Perception, and Ecological Significance1
Authors: FINLAY B. J. , FENCHEL T.
Published: May 2007

ABSTRACT. The ciliate Loxodes has a faint yellow‐brown coloration due to large numbers of electron‐dense granules located in the pellicle. Absorption and action spectra both indicate the presence of a blue‐light receptor, which may be a flavin. Absorbance is minimal at wavelengths greater than 500 nm; there is a major peak at 360 nm and a pronounced shoulder at 435 nm. An action spectrum based on light‐induced escape from oxic water shows a peak at 435 nm and a peak or shoulder at 360 nm. The pigment will generate superoxide when illuminated in the presence of oxygen. Loxodes living in an oxygen gradient in a spectrophotometer cell swims into and remains in anoxic water at light levels ≤10 Wm‐2. Loxodes can be exposed to light levels of 2–20 Wm‐2 in stratified lakes so its photobehavior can explain its periodic absence from oxic water. Photosensitivity in Loxodes may function as part of a predator‐avoidance strategy.
Further Studies on the Organization of the Paraxial Rod of Trypanosomatids1
Authors: FARINA M. , ATTIAS M. , SOUTO‐PADRON T. , DE SOUZA W.
Published: May 2007

ABSTRACT. The fine structure of the paraxial rod of Phytomonas davidi and Herpetomonas megaseliae was analyzed in thin sections of Triton X‐100‐extracted, tannic acid‐glutaraldehyde‐fixed cells and in replicas of quick‐frozen, freeze‐fractured, deeply etched and rotary shadowed cells. The paraxial rod is formed by a complex array of filaments. Two regions, designated as proximal and distal, are formed by two and at least 11 plates, respectively, composed of an association of 25‐nm and 7.0‐nm‐thick filaments which are oriented at an angle of‐50° in relation to the major axis of the axoneme. The intermediate region is less dense and is formed by thin filaments. Short single and Y‐shaped filaments connect the proximal plate to doublets numbers 4 and 7 of the axoneme. Based on the images obtained in stereopairs as well as in photographs obtained before and after inclination of the specimen, a three‐dimensional model of the paraxial rod is proposed.
Structural Aspects of Digestion of Escherichia coli in Tetrahymena1
Authors: NILSSON JYTTE R.
Published: May 2007

Tetrahymena pyriformis ingested Escherichia coli for 15–20 min and the fine structure of food vacuoles was analyzed 5, 15, 30, 60, 90, 120, and 180 min after uptake began. From this analysis, eight vacuolar stages could be defined, and three to four stages were found in each sample. Stage 1 represents forming and newly detached vacuoles with a random distribution of bacteria. Stage 2 is the “dehydration” vacuole in which the bacteria are compacted and a few may lyse. Stage 3, corresponding to the acid phosphatase‐positive stage, has an electron‐dense vacuolar matrix revealing components of lysed bacteria and the translucent coat of intact bacteria. Stage 4 is the “halo” stage where centrally located, intact bacteria are surrounded by lysed material being removed by pinocytic activity of the vacuolar membrane. Stage 5 represents lysis of bacteria remaining intact until this stage; the stage is apparently followed by a second stage 4. Stage 6 contains few bacterial profiles in a smeared homogeneous mass. Stage 7 contains numerous vesicular membranous structures which apparently become transferred to the cytoplasm as such. Stage 8 represents defecation vacuoles derived from fusion of smaller vacuoles. The main findings are as follows: I) Bacterial lysis may occur during acidification of the vacuole prior to fusion with lysosomes. II) Digestion of bacteria apparently occurs in “bursts” as indicated by the extended time that vacuoles in stages 4 and 5 are present. III) Bacterial membranous structures seem to be transferred directly to the cytoplasm of Tetrahymena. IV) Mass defecation occurs 2 h after uptake begins.
Seasonal Distribution of Thermotolerant Free‐Living Amoebae. II. Lake Issaqueena1
Authors: KYLE DENNIS E. , NOBLET GAYLE PITTMAN
Published: May 2007

A quantitative study of the seasonal distribution of thermotolerant (37°C and 45°C), small free‐living amoebae (FLA) was conducted in Lake Issaqueena, a warm, monomictic lake with steep, sloping banks and a maximum basin depth of 10 m in the Piedmont region of South Carolina. Naegleria and Vahlkampfia were the most frequently encountered FLA in littoral sediment and surface water samples whereas Acanthamoeba was most commonly isolated from profundal sediment, especially during late summer. In the water column, FLA populations were highest in a persistent detrital layer; however, few amoebae were isolated from a massive (∼1.5 m thick) layer of Oscillatoria. The only N. fowleri isolated in this study was from the detrital layer. Discussion of the influence of differences in watershed and basin morphology on variations in the size and generic composition of FLA populations for the aquatic ecosystems of Lake Issaqueena and Willard's Pond is included.
Intestinal Mucus Protects Giardia lamblia from Killing by Human Milk1
Authors: ZENIAN ASA J. , GILLIN FRANCES D.
Published: May 2007

We have previously shown that nonimmune human milk kills Giardia lamblia trophozoites in vitro. Killing requires a bile salt and the activity of the milk bile salt‐stimulated lipase. We now show that human small‐intestinal mucus protects trophozoites from killing by milk. Parasite survival increased with mucus concentration, but protection was overcome during longer incubation times or with greater milk concentrations. Trophozoites preincubated with mucus and then washed were not protected. Protective activity was associated with non‐mucin CsCl density gradient fractions. Moreover, it was heat‐stable, non‐dialyzable, and non‐lipid. Whereas whole mucus inhibited milk lipolytic activity, protective mucus fractions did not inhibit the enzyme. Furthermore, mucus partially protected G. lamblia trophozoites against the toxicity of oleic acid, a fatty acid which is released from milk triglycerides by lipase. These studies show that mucus protects G. lamblia both by inhibiting lipase activity and by decreasing the toxicity of products of lipolysis. The ability of mucus to protect G. lamblia from toxic lipolytic products may help to promote intestinal colonization by this parasite.
Isospora elmahalensis n. sp. (Apicomplexa, Eimeriidae), a Parasite of the White‐Cheeked Bulbul (Pycnonotus leucogenys) in Saudi Arabia
Authors: AMOUDI MIKKY A.
Published: May 2007

Isospora elmahalensis n. sp. is described from the Saudi Arabian bird, Pycnonotus leucogenys, from the Elmahala valley. Sporulated oocysts of I. elmahalensis were spherical or nearly subspherical, 19.5–22.5 × 18.5–20 (21.34 ± 0.4 × 19.06 ± 0.5) μm. Oocysts lacked a micropyle, residuum, and polar granule. Sporocysts were ovoid, 14–17.5 × 7–12 (16.08 ± 1.05 × 9.9 ± 1.55) μm, and had a Stieda body and sporocyst residuum, but lacked a substiedal body. Sporozoites were elongated with a clear globule at one end. The host bird belongs to the order Passeriformes.
The Ultrastructure of Vampyrellidium perforans Surek & Melkonian and Its Taxonomic Position Among the Naked Filose Amoebae1
Authors: PATTERSON DAVID J. , SUREK BARBARA , MELKONIAN MICHAEL
Published: May 2007

An account of the fine structure of Vampyrellidium perforans is given. The organism has filose pseudopodia, mitochondria with flattened cristae, and cytoplasmic microtubules, some of which arise from a perinuclear cytoplasmic sheath. Microtubules were observed within nuclei presumed to be at an early stage of division. Relatively massive (non‐filose) pseudopodia are formed by cells feeding by engulfment. The cytoplasm of these pseudopodia has a fibrillar consistency with local aggregations of material. Despite sharing aspects of feeding behavior with vampyrellid filose amoebae, Vampyrellidium perforans is ultrastructurally more similar to Nuclearia, and it is here assigned to nucleariid filose amoebae.
Partial Purification and Characterization of Naegleria fowleriβ‐Glucosidase1
Authors: DAS SIDDHARTHA , SAHA ASISH K. , NERAD THOMAS A. , MARTINEZ A. JULIO , LAMARCO KAREN L. , BASU ALAKANANDA , LEGLER GUNTER , GLEW ROBERT H.
Published: May 2007

Naegleria fowleri cells, grown axenically, contain high levels of β‐D‐glucosidase which catalyzes the hydrolysis of 4‐methylumbelliferyl‐β‐D‐glucopyranoside (4MUGlc) (Km, 0.9 mM), octyl‐β‐D‐glucoside (Km, 0.17 mM), and p‐nitrophenyl‐β‐D‐glucopyranoside at relative rates of 1.00, 2.88, and 1.16, respectively (substrate concentration, 3.0 mM). When the amebae are subjected to freeze‐thawing, sonication, and centrifugation (100,000 g, 1 h), 85% of the β‐glucosidase activity appears in the supernatant fraction. The β‐glucosidase was purified 40‐fold (34% yield) using a combination of chromatographic steps involving DE‐52 cellulose, concanavalin A‐Sepharose, and hydroxylapatite followed by isoelectric focusing. The predominant soluble β‐D‐galactosidase activity in the Naegleria extract copurifies with the β‐D‐glucosidase; the two activities have the same isoelectric point (pI, 6.9), similar heat stabilities, are both inhibited by lactobionic acid (Ki, 0.40 mM), and exhibit optima at pH 4.5, indicating that they are probably the same enzyme. The Naegleriaβ‐D‐glucosidase has an apparent molecular weight of 66,000, a Stokes radius of 25 Å, and a sedimentation coefficient of 4.2S. The β‐glucosidase is not inhibited by conduritol β‐epoxide or galactosylsphingosine but is completely inhibited by 1.25 mM bromo conduritol β‐epoxide. The latter compound, when present in the growth medium, inhibits the growth of the organism and profoundly alters its ultrastructure, the main effect being the apparent inhibition of cytokinesis and the generation of multinucleate cells. The issue of the role of the β‐glucosidase in the metabolism of the ameba and its possible role in pathogenic mechanisms are discussed.
Genetic Heterogeneity in a Natural Population of Acanthamoeba polyphaga from Soil, an Isoenzyme Analysis1
Authors: JACOBSON LISA M. , BAND R. NEAL
Published: May 2007

Acanthamoeba polyphaga, a free‐living, bacterial feeder found in freshwater and soil, reproduces asexually and is morphologicaly distinguishable from other acanthamoebae. Isoenzyme analyses were done on 15 random, clonal isolates from soil. Electrophoretic patterns indicated that enzyme bands occurred in clusters consistent with that of a diploid organism. The data indicates that natural populations of A. polyphaga have a greater genetic diversity than laboratory isolates of other amoebae, resembling the heterogeneity observed for natural populations of bacteria.
Freeze‐Fracture Localization of Filipin‐Sterol Complexes in Plasma‐ and Cyto‐Membranes of Pneumocystis carinii1
Authors: YOSHIKAWA HISAO , MORIOKA HIROYUKI , YOSHIDA YUKIO
Published: May 2007

The polyene antibiotic, filipin, was used as the probe for demonstrating sterols in the freeze‐fractured plasma‐ and cytomembranes of Pneumocystis carinii. The distribution of filipin‐sterol complexes was homogeneous on the plasma membrane throughout all developmental stages from trophozoite to cyst; however, the density of the complexes gradually decreased with the progress of development. In the trophozoite, the density of the complexes was 485 ± 42/μm2 on the P face and 341 ± 27/μm2 on the E face. It was 249 ± 50 on the P face and 132 ± 48 on the E face in the precyst and 138 ± 24 and 59 ± 20, respectively, in the cyst. The membranes of nucleus, mitochondria, and small round bodies showed more or fewer complexes while no complexes were found in the membranes of one endoplasmic reticulum. In nuclear and mitochondrial membranes, some small scattered clusters of complexes were observed. Two types of vacuoles were distinguished: one having many complexes in its membrane and the other having none at all.
Morphology and Morphogenesis of Onychodromus quadricornutus n. sp. (Ciliophora, Hypotrichida), an Extraordinarily Large Ciliate with Dorsal Horns1
Authors: FOISSNER WILHELM , SCHLEGEL MARTIN , PRESCOTT DAVID M.
Published: May 2007

The morphology and the morphogenesis of the freshwater hypotrich ciliate Onychodromus quadricornutus n. sp. have been investigated using living organisms, protargol impregnation, and scanning electron microscopy. Some preliminary and supplementary results about the morphogenesis of O. grandis and Laurentiella acuminata are included. The new species is unique among all described hypotrichs in having four dorsal horns, whose function is unknown. In addition, O. quadricornutus is probably the most voluminous hypotrich ciliate known (2 times 10‐6‐5 times 106μm3). Its morphogenetic pattern resembles the oxytrichids O. grandis and L. acuminata. The strongest apomorphic character, which unites these three species, is probably the multiple fragmentation of the dorsal primordia during morphogenesis. This fragmentation causes the characteristic high number and more or less irregular distribution of the dorsal kineties in the non‐dividing individuals.
New Eimeriid Coccidia from the Canarian Lizard, Gallotia galloti Oudart, 1839
Authors: MATUSCHKA F.‐R. , BANNERT B.
Published: May 2007

One species of Eimeria and one species of Isospora have been discovered in several specimens of the Canarian lizard, Gallotia galloti, collected on Tenerife, Canary Islands, and are described herein as new. The oocysts of Eimeria gallotiae n. sp. are elongate‐ellipsoidal and measure 30.6 (29.1–32.6) by 16.0 (14.0–17.9) μm. Micropyle, oocyst residuum, and polar granule are absent. Oocysts each contain four ellipsoidal sporocysts measuring 14.6 (12.2–17.3) by 9.2 (8.2–11.2) μm. Sporocysts have sporocyst residuum but not a Stieda body. The majority of oocysts are fully sporulated when shed. Few oocysts are excreted unsporulated or in the beginning phase of sporulation. The oocysts of Isopora gallotiae n. sp. are spherical and 16.5 (15.3–17.6) μm in diameter. Micropyle, oocyst residuum, and polar granule are absent. Each oocyst has two lemon‐shaped sporocysts, 11.5 (10.2–12.2) by 7.3 (6.6–8.2) μm, which take up almost the entire space of the oocyst. A sporocyst residuum is present as well as a knob‐like Stieda body and a substieda body. Most oocysts are in the beginning phase of sporulation when excreted and have two spherical sporoblasts. Sporulation is completed within 24 to 28 h at 21 ± 2°C.
Experimental Vaccination of Chicks with Plasmodium gallinaceum Sporozoites. I. Circumsporozoite Proteins Are Expressed by Sporozoites Recovered from Both Salivary Glands and Midguts of Mosquitoes1
Authors: DAHER VALQUIRIA R. , KRETTLI ANTONIANA U.
Published: May 2007

Immunogenicity of Plasmodium gallinaceum Sporozoites for chicks and their in vitro reactivity with normal and specific immune sera were studied. Two sporozoite populations recovered from experimentally infected Aedes fluviatilis were used: sporozoites from salivary glands and sporozoites from midgut oocysts. Populations seven to nine days old of sporozoites recovered from salivary glands were infective for all chicks until the chicks were three weeks old; however, sporozoites recovered from midguts containing oocysts infected these chicks only if isolated on days 8–9, but not on day 7 after the mosquitoes' infective blood meal. Infectivity of the sporozoites was lost after exposure to ultraviolet (UV) light (30 min) or X‐rays (13 krad). Inactivated sporozoites from both sources proved highly immunogenic to chicks that were immunized by several intravenous or intramuscular injections. These parasites elicited a strong humoral immune response in the chicks, as measured by the circumsporozoite precipitation (CSP) reaction. The levels of the CSP antibodies were similar with sporozoites from both sources, there being no detectable differences in the percentage of reactive sporozoites or the intensity of the CSP reaction with sera containing antibodies to either sporozoites from salivary glands or sporozoites from oocysts. These results provide the first evidence that avian malaria sporozoites express the circumsporozoite protein that has been extensively characterized in mammalian malaria (rodent, simian, human sporozoites). Furthermore, we observed that the yields of sporozoites obtained from mosquito midguts, on days 8 and 9 of the P. gallinaceum infection, were at least twice as great as those obtained by salivary gland dissection, even 20 days after a blood meal. This is an advantage since obtaining the midguts is less tedious, as well as more efficient and faster.
Leptomonas ciliatorum n. sp. (Kinetoplastida, Trypanosomatidae) in the Macronucleus of a Hypotrichous Ciliate1
Authors: GÖRTZ HANS‐DIETER , DIECKMANN JOSEF
Published: May 2007

A leptomonad flagellate found in the macronucleus of the hypotrichous ciliate Paraholosticha sterkii carries out its whole life cycle there. The ciliates can divide, encyst, and excyst even when parasitized, and the flagellates are maintained throughout. Parasite‐free ciliates may be rapidly infected. The light‐ and electron‐microscopic structure of the flagellate resembles that of other leptomonads.
Inhibition of Multiplication in Acanthamoeba castellanii by Specific Inhibitors of Ornithine Decarboxylase1
Authors: KIM BYEONG G. , McCANN PETER P. , BYERS THOMAS J.
Published: May 2007

Proliferation of Acanthamoeba castellanii (Neff strain) in either a broth medium or a defined medium was arrested by α‐monofluoromethyldehydroornithine (Δ‐MFMOme), α‐difluoromethylornithine (DFMO), and (R, R')‐δ‐methyl‐α‐acetylenic putrescine (MAP), three specific inhibitors of ornithine decarboxylase. Although all three inhibited the ameba enzyme, Δ‐MFMOme was the most effective inhibitor of multiplication. Growth inhibition was reversed by the addition of polyamines. The inhibitors did not induce differentiation by themselves although DFMO caused encystment when supplemented with CaC12 or MgSO4.
Factors Affecting Motility and Morphology of Cryptosporidium Sporozoites In Vitro1
Authors: WOODMANSEE DOUGLAS B. , POWELL EDWIN C. , POHLENZ JOACHIM F. L. , MOON HARLEY W.
Published: May 2007

In vitro motility and morphology of Cryptosporidium sporozoites were examined in the presence of various solutions. Crude preparations of the bile salt, taurocholic acid, maintained both motility and morphology in a dose‐dependent manner. These effects appeared to be due to the taurocholic acid itself, and not simply due to pH variations, osmotic factors, or contaminants. Lysis of sporozoites was also observed and was found to be dependent on pH, with acidic conditions (pH < 6.2) triggering the lysis.
Fine Structure of a Silica‐Biomineralizing Testate Amoeba, Netzelia tuberculata1
Authors: ANDERSON O. ROGER
Published: May 2007

The fine structure of the cytoplasm and the intracytoplasmic origin of siliceous granules and surrounding cement plaques used in constructing the shell wall of Netzelia tuberculata are described. These organisms construct their test from biogenic siliceous particles and sand grains or other foreign particles (including starch grains apparently from algal prey) coated with biogenic silica. The smooth surface texture of the grains, compared to those of other particle‐gathering testate amoebae, can be expalained by the deposition of a thin surface layer of silica on the foreign particles incorporated into the wall.
Eimeria tahamensis N. Sp. (Apicomplexa: Eimeriidae) from the Arabian Quail (Coturnix delegorguei arabica)1
Authors: Amoudi Mikky A.
Published: May 2007

Eimeria tahamensis n. sp. is described from the harlequin quail (Coturnix delegorguei arabica) from Tahama, Saudi Arabia. The sporulated oocysts of E. tahamensis n. sp. are ellipsoid, 36.5–42 × 25.5–29 (41.2 ± 1.34 × 28.4 ± 0.81) μm, with a thick two‐layered wall and one polar granule but without a micropyle or an oocyst residuum. The sporocysts are ovoid, 14–16 × 9–11.5 (15.3 ± 0.7 × 10.8 ± 0.64) μm, with a knob‐like Stieda body and sporocyst residuum, but without a substiedal body. The sporozoites are often located transversely at the two ends of the sporocysts. The host bird belongs to the order Galliformes.