bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amoeboid Locomotion of Naegleria gruberi: the Effects of Cytochalasin B on Cell‐Substratum Interactions and Motile Behaviour
Authors: PRESTON T. M. , COOPER L. G. , KING C. A. 
Published: May 2007

ABSTRACTThe major manifestations of amoeboid locomotion in Naegleria—cytoplasmic streaming, pseudopod production, cell polarity and focal contact production—require that the actin‐based cytoskeleton be extremely dynamic. Whether these features are causally linked is unclear. In an attempt to answer this question we have used the fungal product cytochalasin B (cyt B) to dissect the motility process. This drug can perturb the organisation of actin filaments both in vivo and in vitro. Essentially cyt B acts as a molecule which can cap the barbed ends of actin filaments. Not surprisingly therefore cyt B has an effect on rates of actin polymerization and the dynamic state of actin in the cytoplasm.We have found that cyt B has a profound effect on focal contact production and breakdown. Within minutes of addition of cyt B focal contact production ceases, existing focal contacts are stabilised but cytoplasmic streaming and pseudopod production are not blocked. In conclusion it is now clear that the state of actin required for focal contact production is different from that required for pseudopod extension and cytoplasmic streaming.
The Ultrastructure of Chaenea teres and an Analysis of the Phylogeny of the Haptorid Ciliates
Authors: LIPSCOMB DIANA. L. , RIORDAN GAVIN P. 
Published: May 2007

ABSTRACTChaenea teres has typical haptorid ultrastructure. The somatic monokinetid has two transverse microtubular ribbons, an overlapping postciliary microtubular ribbon, and a laterally directed kinetodesmal fiber. The evered cytopharynx forms a dome at the apical end of the cell. The base of the dome is surrounded by oral dikinetids. The left, anterior kinetosome of the oral pair is not ciliated and has a transverse microtubular ribbon, a nematodesmata and a single postciliary microtubule. The right, posterior kinetosome is ciliated and has only postciliary microtubules. The kinetosomes at the anterior ends of the somatic kinetics are close together and their transverse microtubules and nematodesmata contribute to the support of the cytopharynx. The transverse microtubules of these oralized somatic kinetosomes, together with those from the oral dikinetids, line the cytopharynx. Accessory or bulge microtubules arise perpendicular to the transverse microtubules. A dorsal brush of three kineties of clavate cilia is found on the cell surface just posterior to the oral region. Mucocysts and a single type of toxicyst are present. The toxicysts are confined to the oral region. There are multiple ovoid macronuclei that stain weakly. Micronuclei were not observed. Cladistic analysis indicates the Chaenea may be most closely related to Fuscheria and Acropisthium. The cladistic analysis also suggests that existing taxonomies of the subclass Haptoria need to be revised. We propose some modifications to Foissner & Foissner's classification that include transferring Helicoprorodon, Actinobolina, the buetschiliids, and the balantidiids to the order Haptorida and recognizing the close relationship between pleurostomes and spathidiids.
Strombidium inclinatum n. sp. and a Reassessment of Strombidium sulcatum Claparède and Lachmann (Ciliophora)
Authors: MONTAGNES DAVID J. S. , TAYLOR F. J. R. , LYNN D. H. 
Published: May 2007

ABSTRACTStrombidium sulcatum is the type species for the genus Strombidium and has been repeatedly referred to over the last 130 yr. However, there are several taxonomic problems associated with it. We discuss why the original description of S. sulcatum lacks resolution to describe a single species. We conclude that: (1) the description of S. sulcatum sensu Fauré‐Fremiet, 1912 be used to diagnose the species; (2) there are ambiguities in several redescriptions of S. sulcatum; and (3) S. sulcatum sensu Lynn et al., 1988 is Strombidium emergens (Leegaard, 1915) Kahl, 1932. From this analysis we present a description for Strombidium inclinatum n. sp. (previously S. sulcatum sensu Fenchel and Jonsson, 1988).
Further Studies on Substrates Inducing Metacyclogenesis in Trypanosoma cruzi
Authors: KRASSNER STUART M. , GRANGER BARBARA , PHERMSANGNGNAM PAT , LE TUAN , LINDEN VIC 
Published: May 2007

ABSTRACTEpimastigotes of Trypanosoma cruzi, Peru strain, incubated in Contreras' artificial triatomine urine transformed into metacyclic trypomastigotes when 10 mM L‐glutamine, L‐asparagine or D‐fructose was added to the medium. Metacyclogenesis with these substrates was comparable to the percent metacyclic morphotype formation induced by L‐proline and significantly greater than that stimulated by 10 mM D‐glucose. Sodium acetate (10 mM) increased transformation induced by L‐proline, and L‐hydroxyproline (10 mM) increased transformation induced by D‐fructose. Phosphoenolpyruvate (10 mM) inhibited L‐proline‐induced metacyclic trypomastigote stage formation. Three antimetabolites, azetidine 2‐carboxylate (5 mM), malonic acid (1 mM), and desthiobiotin (5 mM), completely inhibited D‐fructose‐induced but not L‐proline‐induced transformation. The Costa Rica, Y, and CL strains of T. cruzi showed different patterns of percent metacyclogenesis with substrates that induce transformation in the Peru strain.
Unclassified Protists of Arthropods: The Ultrastructure of Nephridiophaga periplanetae (Lutz & Splendore, 1903) N. Comb., and the Affinities of the Nephridiophagidae to Other Protists
Authors: LANGE CARLOS E. 
Published: May 2007

ABSTRACTObservations by electron microscopy were conducted on Coelosporidium periplanetae (Lutz & Splendore, 1903) Swarczewsky, 1914, an extracellular sporogenic protist in the lumen of the Malpighian tubules of Blatta orientalis Linn., 1758 and other domiciliary cockroaches. Results generally agreed with earlier studies by light microscopy but also allowed a more complete characterization of the species. Some outstanding features of the protist were: amoeboid multinucleate stages (plasmodia) capable of producing cytoplasmic projections for attachment to microvilli of tubules, endogenous formation of spores, differentiation of “generative” and “somatic” nuclei in plasmodia undergoing spore formation, polarized early sporoblasts (a nucleus on one half and a chondriome on the other), and biconcave, ovoid, non‐polarized spores that are retained until maturation by the plasmalemma and residual cytoplasm of the original plasmodium. The new combination Nephridiophaga periplanetae is proposed based on this new, updated information. The family name Nephridiophagidae Sprague, 1970 is resurrected to include N. periplanetae and eleven other species of protists in the Malpighian tubules of arthropods, mostly insects in the orders Dictyoptera and Coleoptera. According to its characteristics, the family Nephridiophagidae cannot be included into any of the currently recognized phyla of protists. It is suggested that it should be temporarily treated as an incertae sedis group of Protista.
Contributions to the Life Cycle of Peneroplis planatus (Fichtel and Moll) Montfort
Authors: FABER WALTER W. , LEE JOHN J. 
Published: May 2007

ABSTRACTDirect observations of schizonts and agamonts releasing megalospheres clarified the asexual phase of the life cycle of Peneroplis planatus and made it most probable that this species has a paratrimorphic life cycle. Specimens with maximum lengths between 837 and 3,503 μm released about 500 to 1,500 megalospheric juveniles, which possessed two chambers (proloculi and flexostyles) prior to emergence from the parental shell. The presence of gamonts was not shown and was only implied by the occurrence of the agamonts. Since agamonts and schizonts have been found from December to May and since asexual reproduction occurs in spring in Elat, sexual reproduction probably occurs at another time of year (June to December). More detailed studies of this species need to be conducted throughout the year to improve our knowledge of the life cycle of this species.
Starvation Induces Tomitogenesis in Miamiensis avidus Strain Ma/21
Authors: GÓMEZ‐SALADÍN EDUARDO , SMALL EUGENE B. 
Published: May 2007

ABSTRACT Miamiensis avidus is a marine polymorphic scuticociliate that undergoes microstome to tomite transformation when nutrients are depleted. This transformation takes place as a result of two consecutive divisions and does not involve a cyst. Tomitogenesis was induced by nutrient deprivation. When returned to nutrient medium tomites transformed into microstomes. Changes in population were noted at one‐hour intervals. Tomites of Miamiensis avidus Ma/2 are compared to dispersal stages in other scuticociliates and hymenostomes.
Incorporation of Label from Acetate and Laurate into the Mannan of Leishmania donovani via the Glyoxylate Cycle
Authors: KEEGAN FRANK P. , BLUM J. JOSEPH 
Published: May 2007

ABSTRACT Leishmania donovani promastigotes in late‐stationary phase incorporated label from [2‐14C]acetate and [1‐14C]laurate into the mannose residues of mannan, thus confirming the presence of a functional glyoxylate bypass in these parasitic protozoa. Isolated, washed calls also incorporated label from [2‐14C]acetate and [1‐14C]laurate into mannan during a 1‐hr incubation in buffer. Glucose had no effect on label incorporation into mannan, but glutamate caused over a four‐fold increase in incorporation from [2‐14C]acetate and a 2.4‐fold increase from [1‐14C]laurate. Staurosporine, a protein kinase inhibitor that inhibits glutamate and alanine oxidation, did not inhibit label incorporation from [2‐14C]acetate into mannan. Hyperosmolality caused about a 33% inhibition of label incorporation into mannan. These results show the glyoxylate cycle and/or the subsequent biosynthetic pathway from fructose‐6‐phosphate to mannan are subject to regulation.
Molecular Genetic Distinction of Pneumocystis carinii from Rats and Humans
Authors: STRINGER JAMES R. , STRINGER SAUNDRA L. , ZHANG JIANXIONG , BAUGHMAN ROBERT , SMULIAN A. GEORGE , CUSHION MELANIE T. 
Published: May 2007

ABSTRACT Pneumocystis carinii from rats and from humans were compared with respect to electrophoretic karyotype, presence of DNA sequences known to be repeated in rat‐derived P. carinii, overall DNA sequence homology, and the sequences at two genetic loci. The organisms from each host species were different in each respect. Neither of two repeated DNAs from rat‐derived P. carinii was found in the genome of human‐derived organisms, and total DNA from rat‐derived P. carinii failed to hybridize to human‐derived P. carinii DNA. The sequences of the α‐tubulin genes from the two P. carinii were strikingly different and the base composition of the α‐tubulin gene from rat‐derived P. carinii was rich in adenine and thymine, while the base composition of this gene from human‐derived P. carinii was rich in guanine and cytosine. The sequence from the 18S rRNA gene of human‐derived P. carinii was twice as divergent from that of rat‐derived P. carinii as the sequence from the corresponding region of Candida albicans was from that of Candida tropicalis. These data show that rats and humans can harbor distinct types of P. carinii that are sufficiently different to suggest that P. carinii from the two hosts could be different species.
Zschokkella mugilis N. Sp. (Myxosporea: Bivalvulida) from Mullets (Teleostei: Mugilidae) of Mediterranean Waters: Light and Electron Microscopic Description
Authors: SITJÀ‐BOBADILLA ARIADNA , ALVAREZ‐PELLITERO PILAR 
Published: May 2007

ABSTRACTA new Myxosporea, Zschokkella mugilis n. sp., was found in the gall bladder of several mugilids. It is distinguished from all previously reported Zschokkella from mugilids by the absence of valve ornamentation and from other species by the size of the spores. Prevalence of infection was 62.5% for Mugil capito, 70% for M. cephalus and 64.3% for Liza saliens. Plasmodia with rhizoids attached to epithelial cells appeared to compromise the host as evidenced in light and transmission electron micrographs presented herein. General ultrastructure and disporous sporogenesis of Z. mugilis resembled other Myxosporeans, but sporogonic cells did not seem to be formed in pansporoblasts.
Corticocolpoda kaneshiroae N. G., N. Sp., a New Colpodid Ciliate (Protozoa, Ciliophora) from the Bark of Ohia Trees in Hawaii
Authors: FOISSNER WILHELM 
Published: May 2007

ABSTRACT Corticocolpoda kaneshiroae n. g., n. sp. was discovered in the bark of Ohia trees (Metrosideros polymorpha) from the Hawaiian Archipelago. Its morphology and infraciliature were studied in live cells, with the scanning electron microscope, as well as in specimens impregnated with protargol, silver nitrate, and silver carbonate. The new genus, Corticocolpoda, belongs to the family Colpodidae and is unique in having a left oral ciliary field (polykinetid) composed of 13–20 equidistantly spaced, paired rows of monokinetids. The new species, C. kaneshiroae, measures 100–300 × 60–250 μm and has a huge vestibulum used to capture large food items, mainly other ciliates. The oral ciliary fields are within the vestibulum and of equal length; the right field is a paroral membrane composed of a single row of dikinetids. Several micronuclei are attached to the ellipsoid macronucleus. The mucocysts are inconspicuous and arranged around the somatic dikinetids. The resting cyst is globular and has a 1–2 μm thin, firm, yellowish inner wall and a 20‐μm‐thick, fragile, hyaline outer wall. Convergent evolutionary paths and a possible polyphyly of the Colpodidae are discussed. An improved key to the genera of the family Colpodidae is provided. Twenty‐three species of ciliates and one flagel***iate (Hemimastix amphikineta), which occurred together with C. kaneshiroae, are new for the fauna of Hawaii and listed in the ecology section.
Effects of Mesoionic Xanthine Analogs On Trypanosoma Musculi Development In Mice
Authors: SEN DILIP K. , MBAGWU GODWIN O. , ADSON ANTHONY 
Published: May 2007

ABSTRACT. Two derivatives of the mesoionic thiazolo[3,2‐a]pyrimidine‐5,7‐diones 1 were prepared and examined for in vivo antiprotozoan activity to study structure‐activity relationships that might lead us to more active derivatives. Mesoionic compounds 1A and 1B were inoculated into Swiss Webster male mice with Trypanosoma musculi infection. the effects were measured by studying parasite populations during the course of patent period (days 9 through 15 post‐infection).The injection of 200 μg of compound 1A along with 5 times 104 trypanosomes affected the level of parasitemia at both the peak and during days 9 to 13 post infection. Experimental animals that received drug 1A prior to and after infection with T. musculi developed significantly lower parasitemia as compared to the control animals at the height of parasite populations (day 11 of observation). the group that received the drug simultaneously with trypanosome infection had significantly lower parasitemias on day 11 and 13 of infection compared to the controls.
Subcellular Localization of the Enzymes of the Arginine Dihydrolase Pathway in Trichomonas vaginalis and Tritrichomonas foetus
Authors: YARLETT NIGEL , LINDMARK DONALD G. , GOLDBERG BURT , ALI MOHARRAMI M. , BACCHI CYRUS J. 
Published: May 2007

ABSTRACTThe enzymes of the arginine dihydrolase pathway were demonstrated in Tritrichomonas foetus and their subcellular localization determined for both T. foetus and Trichomonas vaginalis. Ornithine carbamyltransferase (anabolic and catabolic activities), ornithine decarboxylase and carbamate kinase activity were localized predominately (56–80%) in the non sedimentable fraction of both species. A large proportion (35–40%) of the arginine deiminase was, however, recovered in the large granular fraction, and this distribution was unchanged by increasing the ionic strength of the buffer. Upon density gradient centrifugation the particles containing arginine deiminase activity had an isopycnic density of 1.09 g/ml in percoll, and separated from hydrogenosomes (1.18 g/ml) and lysosomes (1.12 g/ml). Arginine deiminase was also the only enzyme of the dihydrolase pathway which demonstrated latency upon treatment of the 1.09 g/ml fraction with non‐ionic detergents. The results demonstrate the presence of the arginine dihydrolase pathway in T. foetus and indicate that at least a portion of the arginine deiminase in trichomonads is membrane associated.
Occurrence of the Parasitic Dinoflagellate Amoebophrya ceratii in Chesapeake Bay Populations of Gymnodinium sanguineum
Authors: COATS D. WAYNE , BOCKSTAHLER KATRIN R. 
Published: May 2007

ABSTRACTChesapeake Bay populations of the red‐tide dinoflagellate Gymnodinium sanguineum were regularly infected by the parasitic dinoflagellate Amoebophrya ceratii during the summers of 1988–1991. Infections developed inside the nucleus of G. sanguineum and were always lethal to the host. Parasite generation time was ˜ 40 h at 23° C, with the intracellular, trophont phase lasting 39.5 ± 0.3 h, and the extracellular, vermiform stage persisting for ˜ 20 min. Near surface accumulations of G. sanguineum sometimes exceeded 1,000 cells/ml; however, host abundance was relatively low when integrated over the surface mixed layer of each station (mean = 12.2 cells/ml ± 2.96 SE; n = 60). Parasitized hosts were encountered in 75% of the samples where host abundance was ≥ 1 per ml, and epidemic outbreaks (20–40% hosts infected) were observed on several occasions. Epidemic infections were generally located several meters below surface accumulations of G. sanguineum and were always restricted to a narrow region near the pycnocline. Consequently, integrated station values for parasite prevalence were low, with an average 2.7% (± 0.31 SE; n = 60). Parasite induced mortality removed up to 8% of G. sanguineum populations per day, but averaged < 2% of host biomass throughout the Bay. Thus, parasitism by A. ceratii does not appear to be a major factor regulating G. sanguineum bloom in the main stem of Chesapeake Bay.
Chemorepellents in Paramecium and Tetrahymena
Authors: FRANCIS JOSEPH T. , HENNESSEY TODD M. 
Published: May 2007

ABSTRACTAlthough Paramecium has been widely used as a model sensory cell to study the cellular responses to thermal, mechanical and chemoattractant stimuli, little is known about their responses to chemorepellents. We have used a convenient capillary tube repellent bioassay to describe 4 different compounds that are chemorepellents for Paramecium and compared their response with those of Tetrahymena. The classical Paramecium t‐maze chemokinesis test was also used to verify that this is a reliable chemorepellent assay. The first two compounds, GTP and the oxidant NBT, are known to be depolarizing chemorepellents in Paramecium but this is the first report of them as repellents in Tetrahymena. The second two compounds, the secretagogue alcian blue and the dye cibacron blue, have not previously been described as chemorepellents in either of these ciliates. Two other compounds, the secretagogue AED and the oxidant cytochrome c, were found to be repellents to Paramecium but not to Tetrahymena. The repellent nature of each of these compounds is not related to toxicity because cells are completely viable in all of them. More importantly, all of these repellents are effective at micromolar to nanomolar concentrations, providing an opportunity to use them as excitatory ligands in future works concerning their membrane receptors and possible receptor operated ion channels.
Induction of Antibiotic Resistance in Paramecium tetraurelia by the Bacterial Gene APH‐3'‐II
Authors: HAYNES W. JOHN , LING KIT‐YIN , SAIMI YOSHIRO , KUNG CHING 
Published: May 2007

ABSTRACTWe have generated a transformation marker for Paramecium using a Paramecium expression vector (pPXV) and the open reading frame (ORF) of the bacterial antibiotic resistance gene aminoglycoside 3'‐phosphotransferase‐II (APH‐3'‐II or neor) from the transposon Tn5. The expression vector contained a small multiple cloning site between the 5' and 3' non‐coding regions of the calmodulin gene, and Tetrahymena telomere sequences for the stability of the plasmid in Paramecium. After the neor ORF was inserted, the plasmid was referred to as pPXV‐NEO. Delivery of approximately 10–20 picoliters of linearized PXV‐NEO at > 2000 copies/pl into the macronucleus effected 100% transformation. Southern and Northern blot hybridization showed the presence of neor‐specific DNA and RNA, respectively, in all of the transformed clones but not in the untransformed clones. The degree of resistance to G‐418, and the concentrations of neor‐specific DNA and neor‐specific RNA in the clones were proportional to the concentration of the vector injected. We have demonstrated that when the linearized plasmid was injected into the macronucleus, the prokaryotic sequence conferred an antibiotic resistance to Paramecium despite codon‐usage differences.
Ribosomal RNA‐Based Oligonucleotide Probes to Identify Marine Green Ultraphytoplankton1
Authors: KNAUBER DONNA C. , BERRY EUGENE S. , FAWLEY MARVIN W. 
Published: May 2007

ABSTRACTOligonucleotide probes based on small subunit 18S rRNA variable region sequences, were designed and used to discriminate groups of marine green ultraphytoplankton of similar size and morphology. Hybridization of probes was visualized using a combination of biotinylated oligonucleotides and fluorescein labeled avidin. Increased fluorescent signal was generated by building a complex of biotinylated probe, fluorescein labeled avidin and biotinylated anti‐avidin. Cells of one phylogenetic group were easily differentiated from morphologically similar cells of a different phylogenetic group. Design of specific probes allowed identification of Mantoniella squamata, Micromonas pusilla, Pseudoscourfieldia marina and the micromonadophyte clone CCMP1194. This technique should be readily adaptable to open ocean samples and should greatly facilitate the description and quantification of ultraphytoplankton in the open ocean.
Ubiquity of Cysteine‐ and Metalloproteinase Activities in a Wide Range of Trypanosomatids
Authors: BRANQUINHA MARTA H. , VERMELHO ALANE B. , GOLDENBERG SAMUEL , BONALDO MYRNA C. 
Published: May 2007

ABSTRACTWe have analysed the proteinase profiles of 11 species from 7 different genera of trypanosomatids by in situ detection of enzyme activities on SDS‐PAGE gels containing co‐polymerized gelatin as substrate, and the use of specific proteinase inhibitors. Our survey indicates that while cysteine‐ and metalloproteinases are distributed ubiquitously among trypanosomatids, there are marked differences between the enzyme profiles from the monogenetic (Crithidia, Herpetomonas, Leptomonas) and digenetic (Trypanosoma, Endotrypanum, Phytomonas, Leishmania) species. The detected metalloproteinase activities, ranging in size from 50–100 kDa, partitioned into the detergent‐phase after Triton X‐114 extraction, while most of cysteine proteinases, of three distinct molecular mass ranges (30–50 kDa, 80–100 kDa and 116–205 kDa), partitioned into the aqueous phase. Thus, within this group of organisms, the metalloproteinase activities seem to be predominantly membrane‐associated proteins. We also show that the plant parasites of the genus Phytomonas exhibit a distinctive cysteine proteinase profile that might be exploited further as a criterion for taxonomy of the genus.
Development of a Rapid Detection Procedure for Ctyptosporidium, Using In Vitro Cell Culture Combined with PCR
Authors: ROCHELLE PAUL A. , FERGUSON DONNA M. , HANDOJO TROY J. , LEON RICARDO DE , STEWART MIC H. , WOLFE ROY L. 
Published: May 2007

SUMMARYA detection, viability, and infectivity assay was developed for Cryptosporidiurn parvum. Oocysts or excysted sporozoites were inoculated onto monolayers of CaCo‐2 cells grown on chamber slides. C. parvum infection was monitored by three methods: a) application of a fluorescein‐labeled anti‐sporozoite antibody; b) PCR of a heat‐shock protein gene fragment; and c) detection of mRNA from the heat‐shock protein gene by RT‐PCR.