bluuebunny/crossref_metadata_2025 huggingface dataset:
Henneguya adherens N. Sp. (Myxozoa, Myxosporea), Parasite of the Amazonian Fish, Acestrorhynchus falcatus
Authors: AZEVEDO CARLOS , MATOS EDILSON
Published: May 2007

ABSTRACT. A new species of myxosporean from the gill filaments of the freshwater teleost fish, Acestrorhynchus falcatus collected in the Amazon river is described from light and transmission electron microscope observations. The mature spores (total length 32.3 [30.7–35.1] μ) and all developmental stages were found in the same sporogonic plasmodium. The ellipsoidal spore body consists of 2 unequal shell valves adhering together along the suture lines. Each valve, tapering as a caudal projection, forms a long tail (length 20.5 [18.0–21.7] μm). The tail was surrounded by a homogeneous sheath on its length. The polar capsules measuring 3.1 × 1.2 μm contain 3–4 coils of the polar filament. All surfaces of the immature and mature spores were surrounded by a closely adherent homogenous structural sheath, mainly thicker around the tails. The taxonomic affinities of this parasite to other species are discussed.
Small Subunit Ribosomal DNA Phylogeny of Various Microsporidia with Emphasis on AIDS Related Forms
Authors: BAKER MICHAEL D. , VOSSBRINCK CHARLES R. , DIDIER ELIZABETH S. , MADDOX JOSEPH V. , SHADDUCK JOHN A.
Published: May 2007

ABSTRACT. Phylogenetic analysis of the small subunit ribosomal DNA of a broad range of representative microsporidia including five species from humans (Enterocytozoon bieneusi, Nosema corneum, Septata intestinalis, Encephalitozoon hellem and Encephalitozoon cuniculi), reveals that human microsporidia are polyphyletic in origin. Septata intestinalis and E. hellem are very similar to the mammalian parasite E. cuniculi. Based on the results of our phylogenetic analysis, we suggest that S. intestinalis be designated Encephalitozoon intestinalis. Furthermore, analysis of our data indicates that N. corneum is much more closely related to the insect parasite Endoreticulatus schubergi than it is to other Nosema species. This finding is supported by recent studies which have shown a similarity between E. schubergi and N. corneum based on the origin and development of the parasitophorous vacuole. Thus these opportunistic microsporidian parasites can originate from hosts closely or distantly related to humans. Finally, the phylogeny based on small subunit ribosomal DNA sequences is highly inconsistent with traditional classifications based on morphological characters. Many of the important morphological characters (diplokaryon, sporophorous vesicle, and meiosis) appear to have multiple origins.
Cryopreservation and Storage of Parasitic Protozoa in Liquid Nitrogen
Authors: DIAMOND LOUIS S.
Published: May 2007

ABSTRACT. In 1961 I reported the first successful attempt to cryopreserve and store protozoa in liquid nitrogen. In this presentation, drawing on more than 30 years of personal experience, I discuss the factors which I consider to be most critical to the successful preservation and long term storage of several species of parasitic protozoa in liquid nitrogen. I then present my most successful protocol for cryopreservation of these parasites. Finally. I cite some longevity records for a variety of protozoa stored in liquid nitrogen vapor at the Laboratory of Parasitic Diseases. The oldest record is for a monoxenic culture of Entamoeha histolytica grown in association with Crithidia fasciculata that was frozen on January 6, 1961. Thirty‐two years and 11 months later both parasites were recovered and used to initiate new culture lines.
The Primary Structure of an Entamoeba histolyticaβ‐Hexosaminidase A Subunit
Authors: BEANAN MAUREEN J. , BAILEY GORDON B.
Published: May 2007

ABSTRACT. An Entamoeba histolytica gene (hex‐A1) that encodes subunit A of the lysosomal enzyme β‐hexosaminidase has been cloned and sequenced. The inferred 59 kDa hex‐A1 protein has the same molecular weight and 32% amino acid residue identity with the human and mouse proteins and 28% residue identity with the Dictyostelium protein. Northern blot analysis identified a mRNA of approximately 1.6 kb, which is in agreement with the expected size of a mRNA encoding the 522 amino acid hex‐A1 protein. Southern blot analysis indicated the presence of at least two β‐hexosaminidase A subunit genes.
Evidence for Heterotrimeric GTP‐Binding Proteins in Toxoplasma gondii
Authors: HALONEN SANDRA K. , WEIDNER EARL , SIEBENALLER JOSEPH F.
Published: May 2007

Toxoplasma gondii, an intracellular protozoan parasite, resides within a host‐derived vacuole that is rapidly modified by a parasite‐secreted membranous tubular network. In this study we investigated the involvement of heterotrimeric G proteins in the secretory pathway of T. gondii. Aluminum fluoride (AIFn), a specific activator of heterotrimeric G proteins, induced secretion from isolated tachyzoites of T. gondii in vitro, as seen by light optics and electron microscopy. In Western blot analyses, antibodies to G protein α subunits reacted with 39–42 kDa proteins from T. gondii isolates. Antibodies to Goα and Gsα coupled to the fluorescent probe fluorescein isothiocyanate localized to the paranuclear region of T. gondii. Gi3α immunoprobes were confined to the cytoplasmic matrix of T. gondii and also labeled the parasitophorous vesicle. Fluorescein isothiocyanate‐conjugated GA/1, an antipeptide antisera directed toward the GTP binding site common to G protein α subunits, was confined to the lateral cytoplasmic domain of the parasites where secretion is most prominent. In time‐sequence studies using the GA/1 probe, the immunoreactive material shifted position daring invasion of target cell to areas of active secretion.
Osmotic and Metabolic‐Induced Changes in Light Scattering of Leishmania donovani as Measured by Flow Cytometry
Authors: BLUM J. JOSEPH , BALBER ANDREW E.
Published: May 2007

Leishmania donovani promastigotes were collected from cultures in log and stationary phases of growth and resuspended in Hank's Balanced Salt Solution containing 1 mM sodium acetate. Changes in the forward and side scattering of the cells were measured by flow cytometry in response to acute changes in osmolality and to the addition of several different substrates. Forward and side scattering of cells from log phase cultures decreased when the osmolality was decreased by the addition of H2O and increased when the osmolality was increased by the addition of NaCl. Cells from stationary phase cultures had about the same forward scatter as cells from log phase cultures, but almost a four‐fold lower side scatter, and their side scatter values did not change significantly in response to a reduction in osmolality. Microscopic observation showed that both log and stationary cells got longer and thinner, on average, in response to hyperosmolality. The light scattering properties of log (but not of stationary) cells changed in a reproducible manner when substrates were added to the buffer. The ratio of forward to side scatter increased in the following order: controls in balanced salt solution >aspartate >glutamate, glucose or 2‐deoxyglucose >alanine >proline. Thus the light scattering properties of L. donovani promastigotes change with culture age, in response to changes in osmolality, and, in log phase cells, in response to the presence of several substrates.
Nucleotide Sequences of DNA Fragments of Encephalitozoon cuniculi Amplified by Polymerase Chain Reaction with Primers Regarded as Specific for Echinococcus
Authors: NAGANO HIDEKI , SATOH CHIAKI , FURUYA KOJI
Published: May 2007

Encephalitozoon‐like spores were separated from a human echinococcal liver lesion, which was caused by Echinococcus multilocularis. They were found to fall into the species Encephalitozoon cuniculi, which was shown to have En. cunniculi specific DNA by way of polymerase chain reaction (PCR). We also used PCR to genetically discriminate between the En. cuniculi spores and the Ec. multilocularis larvae. Two primer sets, known to be specific for Echinococcus, were examined. These primers were expected to work normally when the two quite different DNA preparations were tested as templates, i.e. only Echinococcus DNA could give a positive signal in the PCR tests. However, it was found that the two Echinococcus‐specific primer sets could amplify not only EC. multilocularis DNA, but also En. cuniculi spore DNA. We then tried to determine the order of nucleotides in the Echinococcus‐specific primers‐amplified En. cuniculi PCR products and compared the determined sequences with those of Ec. multilocularis. The results clearly indicated that sequencing made little difference between En. cuniculi and Ec. multilocularis.
A Description of Paulinella indentata N. Sp. (Filosea: Euglyphina) from Subtidal Coastal Benthic Sediments
Authors: HANNAH FIONA , ROGERSON ANDREW , ANDERSON O. ROGER
Published: May 2007

ABSTRACT. Paulinella indentata n. sp. is described from benthic sandy sediments of Kames Bay, Scotland. The description is based on light and scanning electron microscopical observations. This marine, testate amoeba has filose pseudopodia, sometimes branched, extending up to 50 μm from the aperture. Tests are oval in outline (c. 15.8 × 9.8 μm) pale yellow in colour with a short collar. The most important diagnostic feature is the morphology of the surface scales which are arranged in staggered rows. Each cell is covered with around 22 scales (c. 5.7 × 2.9 μm). Scales are rectangular, curved with rounded corners and markedly indented along their median axis. They have a hollow channel running below each ridge and their surface is punctuated with rows of pores. This is the first isolation of Paulinella from benthic marine sediments.
Effect of Conditioned Media from Several Cell Types on Invasion by Eimeria adenoeides Sporozoites1
Authors: AUGUSTINE PATRICIA C. , JENKINS MARK C.
Published: May 2007

ABSTRACT. The effect of conditioned media (media aspirated from a variety of cell cultures after 4 d of growth) on cellular invasion by sporozoites of the turkey coccidium, Eimeria adenoeides, was examined. Conditioned medium from turkey kidney cells and baby hamster kidney cells failed to alter invasion. However, conditioned medium from turkey cecal cell cultures produced a significant (P ≤ 0.05), two‐fold increase in invasion over control medium in a variety of cell types. Retentates of conditioned medium from the turkey cecal cells that were passed through microconcentrators having molecular mass cutoffs of 50, 100, and 300 kDa similarly enhanced invasion over retentates from control medium. However, retentates from microconcentrators with a cutoff of 1,000 kDa failed to enhance invasion. Pretreatment in conditioned medium, followed by washing of sporozoites prior to inoculation into cultures, did not result in enhanced invasion. Moreover, when the interval between inoculation of sporozoites into cells and fixation of cultures was reduced to less than 3 h, no enhancement of invasion occurred. Conditioned medium from turkey cecal cells that were grown in the presence of 35S‐translabel had at least two labeled bands at 150 kDa and > 200 kDa that were absent in conditioned media from turkey kidney and baby hamster kidney cells.
The Lobster Parasite Anophryoides haemophila (Scuticociliatida: Orchitophryidae): Nuclear 18S rDNA Sequence, Phylogeny and Detection Using Oligonucleotide Primers
Authors: RAGAN MARK A. , CAWTHORN RICHARD J. , DESPRES BEATRICE , MURPHY COLLEEN A. , SINGH RAMA K. , LOUGHLIN MICHAEL B. , BAYER ROBERT C.
Published: May 2007

ABSTRACT. We have determined the nucleotide sequence of the nuclear gene encoding small‐subunit ribosomal ribonucleic acid of the ciliate Anophryoides haemophila, a parasite of the American lobster Homarus americanus. The gene is 1763 bp in length, and has a guanosine‐plus‐cytosine content of 43.9%. Inferred phylogenetic frameworks strongly support the monophyly of the scuticociliates, and suggest that order Scuticociliatida should be elevated to at least subclass rank. Oligonucleotide probes based on A. haemophila ssu‐rDNA can discriminate between DNAs of A. haemophila and other investigated hymenostome ciliates, and effectively prime polymerase chain reaction‐based detection of A. haemophila deoxyribonucleic acid against at least a 1600‐fold excess of total deoxyribonucleic acid from H. americanus.
Choanoflagellates (Sarcomastigophora, Protozoa) from the Coastal Waters of Taiwan and Japan. I. Three New Species
Authors: HARA SEIKO , CHEN YUH‐LING L. , SHEU JIA‐CHI , TAKAHASHI EIJI
Published: May 2007

Three new acanthoecidaean species collected from the coastal waters of Taiwan and Japan are described: Acanthocorbis camarensis n. sp. resembles Acanthocorbis unguiculata in lorica morphology, but differs in having regularly arranged longitudinal and transverse costae at the anterior lorica chamber, and in lacking a nail at the apical end of anterior spine; Diaphanoeca spiralifurca n. sp. is characterized by the spiral arrangement of the costal strips in the posterior half of the lorica chamber and is closely related to Diaphanoeca grandis; Stephanoeca supracostata n. sp. is closely related to Stephanoeca elegans, but differs in having an additional transverse costa at the anterior lorica chamber.
Identification of C31 and C32 Sterols in Pneumocystis carinii hominis‐Infected Human Lungs
Authors: KANESHIRO EDNA S. , SWOṄGER MARDIE , KREISHMAN GEORGE , BROOKS ELWOOD , JAYASIMHULU KOKA , PARISH EDWARD J. , BEACH DAVID H.
Published: May 2007

SUMMARY Two sterols in autopsied whole lung specimens obtained from Pneumocystis carinii pneumonia patients were detected by gas‐liquid chromatography and their structures were elucidated by mass spectrometry and nuclear magnetic resonance spectrometry. Both were in the lanosterol series; the C31 sterol, with a methyl group at C‐24, was identified as euphorbol, and the more abundant C32 sterol, with an ethyl group at C‐24, is given the trivial name pnemocysterol.
Experimental tissue cyst induced Toxoplasma gondii infections in dogs
Authors: LINDSAY D. S. , DUBEY J. P. , BUTLER J. M. , BLAGBURN B. L.
Published: May 2007

Tissue cyst induced Toxoplasma gondii infections were examined in 2 beagle dogs orally inoculated with tissue cysts. Neither dog developed clinical signs of toxoplasmosis. Both dogs developed low antibody titers to T. gondii. The MAT and IFAT were superior to the LAT and IHT tests for detecting antibodies to T. gondii.
Leishmania donovani Attachment Stimulates PKC‐Mediated Oxidative Events in Bone Marrow‐Derived Macrophages
Authors: BHUNIA ANIL K. , SARKAR DWIJEN , DAS PIJUSH K.
Published: May 2007

We investigated activation signaling events in bone marrow‐derived macrophages after infection with Leishmania donovani, an intracellular parasite of macrophages. Leishmania donovani infection caused a general suppression of activation parameters like O2‐ and NO production. However, conditions which allow parasite attachment and prevent entry resulted in triggering of O2‐ and NO production and stimulation of O2 consumption. Optimal NO and O2‐ production occurred when bone marrow‐derived macrophages and Leishmania ratio was 1:100. The activation signal for O2‐ production was initiated 15 min after parasite attachment, whereas augmentation of NO production started 6 h after attachment. Activation of O2‐ and NO generation by L. donovani attachment was inhibited by staurosporine as well as by prolonged treatment of phorbol myristate acetate suggesting a protein kinase C‐dependent mechanism. Translocation studies showed that protein kinase C activity in cell membrane fraction rapidly and transiently increased following parasite attachment. No such protein kinase C translocation event occurred in L. donovani infected bone marrow‐derived macrophages. Phorbol myristate acetate was found to stimulate membrane translocation of protein kinase C in parasite attached cells whereas it was impaired in infected cells. However, both attachment and infection induced a similar shift of phorbol receptors from cytosolic to membrane fraction indicating that in infected cells the translocation of protein kinase C protein was not impaired but the activity of the membrane associated enzyme was somehow inhibited. These results suggest that although internalization of intracellular parasites like L. donovani caused inhibition of nitrite and superoxide release, mere attachment on macrophage surface resulted in an activation of protein kinase C‐mediated downstream oxidative events.
Combined Action of Inhibitors of S‐Adenosylmethionine Decarboxylase with an Antimalarial Drug, Chloroquine, on Plasmodium falciparum
Authors: DAS BHAGWAN , GUPTA RASHMI , MADHUBALA RENTALA
Published: May 2007

ABSTRACT. Methylglyoxal bis (guanylhydrazone), (MGBG) a potent competitive inhibitor of S‐adenosyl‐L‐methionine decarboxylase activity, Berenil, a trypanocidal agent and chloroquine, the commonly used antimalarial resulted in a dose dependent inhibition of Plasmodium falciparum in vitro. The IC50 values of MGBG, Berenil and chloroquine were 224 μM, 40 μM and 42 nM respectively. Parasites treated with different concentrations of MGBG or Berenil were arrested at the trophozoite stage of the erythrocytic cycle. The combined action of chloroquine (10 nM) with either Berenil (0.1 mM) or MGBG (0.1 mM) on P. falciparum growth showed an additive inhibitory effect. The effect of these inhibitors alone and in combination on polyamine biosynthesis is also reported.
Phylogenetic Position of Amblyospora Hazard & Oldacre (Microspora: Amblyosporidae) Based on Small Subunit rRNA Data and Its Implication for the Evolution of the Microsporidia
Authors: BAKER MICHAEL D. , VOSSBRINCK CHARLES R. , BECNEL JAMES J. , MADDOX JOSEPH V.
Published: May 2007

ABSTRACT. Sequences of the small subunit rRNA genes of Amblyospora californica and an Amblyospora sp. from Culex salinarius were determined. These sequences were compared phylogenetically with 16 other microsporidia. The results suggest Amblyospora forms a sister taxon to the rest of the microsporidia examined. The basal position of Amblyospora is discussed with respect to the evolution of microsporidian life cycles. These sequences represent the longest microsporidian small subunit rRNA genes sequenced to date, 1,359 and 1,358 bp, respectively. Structural features and GC content (49% for both) are comparable to those of other microsporidia which have been sequenced.
Receptor‐Mediated Calcium Influx in Chlamydomonas reinhardtii
Authors: EVANS JOHN H. , KELLER LAURA R.
Published: May 2007

ABSTRACT. Alcian blue acts as a secretagogue and chemorepellent in a variety of unicellular eukaryotes. We report that alcian blue stimulates flagellar excision and induction of RNA encoding flagellar proteins in Chlamydomonas reinhardtii. Flagellar excision by alcian blue is dependent on extracellular Ca2+ and is blocked by La3+, ruthenium red, and neomycin, and so is similar to flagellar excision by acid shock. However, the adf‐l mutant excises its flagella following alcian blue treatment, but not following acid shock, thus genetically distinguishing alcian‐blue‐induced excision from acid‐shock‐induced excision. Wild‐type, but not adf‐1, cells regrow their flagella in the continued presence of alcian blue. Wild‐type cells that regrow flagella in the presence of alcian blue fail to excise their flagella in response to either increased concentrations of alcian blue or to acid shock. Alcian blue treatment of cells also induces RNA encoding flagellar components, but in a manner distinct from other means of stimulation. These results suggest that treating Chlamydomonas with the secretagogue alcian blue initiates a Ca2+ influx pathway and that prolonged treatment with alcian blue desensitizes the acid‐shock‐activated Ca2+ influx pathway to acid treatment. Alcian blue will thus be a useful excitatory ligand in future studies of receptor‐mediated Ca2+ signaling in the Chlamydomonas flagellar regeneration system.
Cloning and Molecular Analysis of the Plasma Membrane Ca2+ ‐ATPase Gene in Paramecium tetraurelia
Authors: ELWESS NANCY L. , VAN HOUTEN JUDITH L.
Published: May 2007

ABSTRACT. We have determined the DNA sequence of the gene encoding the protein of the plasma membrane Ca2+‐ATPase in Paramecium tetraurelia. The predicted amino acid sequence of the plasma membrane Ca2+‐ATPase shows homology to conserved regions of known plasma membrane Ca2+‐ATPases and contains the known binding sites for ATP (FITC), acylphosphate formation, and calmodulin, as well as the “hinge” region: all characteristics common to plasma membrane Ca2+‐ATPases. The deduced molecular weight for this sequence is 131 kDa. The elucidation of this gene will assist in the studies of the mechanisms by which this excitable cell removes calcium entering through voltage gated calcium channels and the pump functions in chemosensory signal transduction.
Osmotic Homeostasis in Dictyostelium Discoideum: Excretion of Amino Acids and Ingested Solutes
Authors: STECK THEODORE L. , CHIARAVIGLIO LUCIUS , MEREDITH STEPHEN
Published: May 2007

ABSTRACT. The response to osmotic stress in axenically cultured Dictyostelium discoideum was examined. Hypoosmotic buffers elicited two changes in the large (‐50 mM) cytosolic pool of amino acids: a) the total size of the pool diminished, while b) about half of the initial pool was excreted. Hyperosmotic stress had the opposite effect. Among the predominant amino acids in the pool were glycine, alanine and proline. Putrescine, the major diamine, was neither excreted nor modulated. Recently ingested radioactive amino acids were excreded in preference to those in the cytoplasm, suggesting that the endocytic pathway might be involved in water excretion. Furthermore, hypoosmotic stresss strimulated the selective exretion of small, membrane‐impermeable fluorescent dyes which had been ingested into endocytic vacuoles. Caffeine inhibited the excretion of the fluorophores but not the amino acids. We conclude that the response of Dictyostelium to osmotic stress is complex and includes both modulation of the cytoplasmic amino acid pool and the excretion of amino acids and other small solutes from the endocytic pathway.
The Leishmania hertigi (Kinetoplastida; Trypanosomatidae) Complex and the Lizard Leishmania: Their Classification and Evidence for a Neotropical Origin of the Leishmania‐Endotrypanum Clade
Authors: NOYES HARRY A. , ARANA BYRON A. , CHANCE MICHAEL L. , MAINGON RHAIZA
Published: May 2007

ABSTRACT. The relationships of the Leishmania hertigi complex and the lizard Leishmania species to the main groups of mammalian Leishmania and Endotrypanum parasites were examined. Restriction fragment length polymorphisms and sequences of small subunit ribosomal RNA genes and hybridization studies of kinetoplast DNA indicated that the L. hertigi complex was more closely related to the genus Endotrypanum than to the genus Leishmania. The lizard Leishmania species were found to be at the crown of the Leishmania tree. The data provides strong evidence for a Neotropical origin of the Endotrypanum/Leishmania clade since the parasites closest to the root of the tree are all found exclusively in the Neotropics. The evolution of the Leishmania/Endotrypanum clade in relation to the evolution of the known hosts of these parasites is discussed.
Cultivation of Rabbit Pneumocystis carinii on Cells Derived from Rabbit (Oryctolagus cuniculus)
Authors: POLACK BRUNO , CERÉ NICOLAS , RHUN DANIELLE LE , GUILLOT JACQUES , CHERMETTE RENÉ
Published: May 2007

. Cultivation of Pneumocystis carinii from rabbit onto cell monolayers was intended. Three cell types were used: rat lung derived cell line L2 and canine kidney derived cell line MDCK, and primary epithelial rabbit lung cells derived from 20 days old foetuses. These primary cells were also immortalized by transfection of the coding sequences for the large and small T antigens of the SV40 virus. P. carinii were extracted from lungs of corticoid treated young rabbits and were purified on Ficoll. In vitro development of P. carinii was assessed by counting the number of attached parasites on cells after staining. No development was observed on L2 and MDCK cell lines. On the contrary, a development was observed on rabbit derived cells with a threefold increase of attached parasites on the third day of culture. Immortalized cells allowed also multiplication of attached P. carinii. These results are similar to those obtained with culture of rodent P. carinii onto cell monolayers.
Ubiquinone Synthesis by Pneumocystis carinii: Incorporation of Radiolabeled Polyprenyl Chain and Benzoquinine Ring Precursors
Authors: SUL DONGGENUN , KANESHIRO EDNA S.
Published: May 2007

Radiolabeled mevalonic acid was incroporated in vitro into Pneumocystis carinii ubiquinone homologs, CoQ9 and CoQ10, dermostrating the isoprenoid branch pathway forming the polyprenyl chain of ubiquinone is functional in the organism. Radiolabeled shikimic acid, tyrosine and p‐hydroxybenzoic acid were also incorporzated into the two ubiquinone homologs, indicating that P. carnii also possesed the biological pathway for de novo synthesis of the CoQ benzoquinone ring.
Microsporidiosis in HIV‐Positive Children in Madrid (Spain).
Authors: AGUILA CARMEN DEL , NAVAJAS RAQUEL , GURBINDO DOLORES , RAMOS JOSE TOMAS , JOSE MELLADO M , FENOY SOLEDAD , ANGELES MUÑOZ FERNANDEZ M , SUBIRATS MERCEDES , RUIZ JESUS , PLENIAZEK NORMAN J.
Published: May 2007

A prospective study was carried out to determine the prevalence rates of microsporidiosis and other enteroparasites in HIV‐positive children in the Madrid area. HIV‐positive pediatric patients from three hospitals were entrolled in the study. A total of 293 samples (158 stool and 127 urine) were collected from 83 children whose mean age was 6.3 years and hed a mean CD4 count of 504.7/mm3 (range 1‐2,220/mm3), 48 of whom suffered diarrhea at the time of the study. Microsporidia indentification was investigated in stool and unrine samples using Weber's chromotrope‐based strain, IIF and PCR species‐specific tests. Enteric parasites were identified in 32.5% of the children. Cryptosporidium sp. was the most common parasite encuntered (14.4%), followed by Blastocytis sp. (9.6%) and Giardia duodenalis (8.4%). Microsoridia was only found in the stools of one child (1.2% of total and 2% of those with diarrhea) and Enterocytozoon bieneusi was demonstrated by PCR. The patient was 10 years old, Presented non‐chronic diarrhea and his CD4 count was 298/mm3. These date differ from those previously reported by us in HIV‐positive adults (13.9%) in the same area, although this group showed more severely depressed CD4 lymphocyte counts than children. New epidemiological studies should be carried out to elucidate whether additional risk factors exist betwen these groups.
Characterization of Rat CD4 T Cell Clones Specific for the Major Surface Glycoprotein of Pneumocystis carinii
Authors: THEUS SUE A. , ANDREWS RYAN P. , MICHAEL J. LINKE  , WALZER PETER D.
Published: May 2007

ABSTRACT. Pneumocystis carinii are coated by abundant heterogenous major surface glycoproteins (MSGs), which facilitate interaction with the host. We have produced MSG‐specific T‐cell clones from the spleens of P. carinii‐exposed Lewis rats and analyzed five for antigen specificity to native MSG and a recombinant form of MSG, cell surface markers, and cytokine profiles. All five of the clones were CD4+. All of the clones proliferated specifically to both the native MSG and the recombinant MSG only in the presence of antigen presenting cells demonstrating that the response is antigen/driven rather than mitogen/driven. All five of the clones secreted IL‐2 and IFN‐γ, although in differing amounts, implicating a Th l response. Only one of the clones produced any detectable IL‐4. This is the first report of T cell clones responsive to a specific antigen of P. carinii, MSG. We conclude that the T cell clones will be helpful in mapping protective epitopes present in MSG and in functional studies of MSG.
Species Richness and Abundance of Naked Amebae in the Rhizoplane of the Desert Plant Escontria chiotilla (Cactaceae)
Authors: RODRÍGUEZ‐ZARAGOZA SALVADOR , GARCÍA SOLEDAD
Published: May 2007

ABSTRACT. The species richness and quantity of naked amebae were determined in the bulk soil and rhizoplane of the desert plant Escontria chiotilla in the Valley of Tehuacan, Mexico. Samples from bulk soil were taken at 10‐cm and 30‐cm depths in April, May and July, 1993, and from roots and soil at a 10‐cm depth in June and July, 1994. Quantity of amebae obtained by Most Probable Number method increased in the rhizoplane by two orders of magnitude after rains. Likewise, the countable population of amebae doubled in numbers at both the 10‐ and 30‐cm depths after rains. We isolated 163 strains from both root and soil environments, which were grouped into 40 bactivorous and/or generalist species belonging to 19 genera. Species richness showed no clear dominance of a particular genus in either bulk soil or root. Acanthamoeba (groups II and III, Pussard & Pons) and Vahlkampfia accounted for 12.5% and 15% of the total number of species, respectively. However, greater species richness was found in bulk soil than on root surfaces. We concluded that the diversity of naked amebae, taken as numbers of individuals (or as biomass) of each species and its evenness, is still needed to assess the ecological roles of Acanthamoeba and Vahlkampfia in the soil environment.
Rediscovery of Paramecium duboscqui Chatton & Brachon, 1933, and a Description of Its Characteristics
Authors: SHI XINBAI , JIN MEILEI , LIU GUIJIE
Published: May 2007

ABSTRACT. Paramecium duboscqui Chatton & Brachon, 1933, was rediscovered in Harbin, China, in 1974. In addition to the morphological features described by Chatton and Brachon, more details such as the silver‐line system, buccal apparatus, stomatogenetic pater, mating types and temperature adaptation are described here. Although minor differences exist between the strains from France and China, the evidence indicates that they are really the same species and a member of the “bursaria” group.
Identification of Significant Variation in the Composition of Lipophosphoglycan‐like Molecules of E. histolytica and E. dispar1
Authors: Moody Susan , Becker Steven , Nuchamowitz Yael , Mirelman David
Published: May 2007

The lipophosphoglycan‐like (LPG‐like) molecules of E. histolytica virulent strains are clearly distinct from those of the avirulent E. histolytica and E. dispar strains. Abundant ‘LPG’ levels are apparently limited to virulent strains, while lipophosphopeptidoglycans (‘LPPG's) are common to both virulent and avirulent strains of E. histolytica and E. dispar. It is therefore conceivable that ‘LPPG’ performs a function that is essential to survival within the host, while the ‘LPG’ performs a more specific function related to virulence.
Functional Heterogeneity of Colonic Adenocarcinoma Mucins for Inhibition of Entamoeba histolytica Adherence to Target Cells1
Authors: Göttke Markus U. , Keller Kathy , Belley Adam , Garcia Rosa‐Maria , Hollingsworth Michael A. , Mack David R. , Chadee Kris
Published: May 2007

Mucins secreted from the gastrointestinal epithelium form the basis of the adherent mucus layer which is the host's first line of defense against invasion by Entamoeba histolytica. Galactose and N‐acetyl‐D‐galactosamine residues of mucins specifically inhibit binding of the amebic 170 kDa heavy subunit Gal‐lectin to target cells, an absolute prerequisite for pathogenesis. Herein we characterized the secretory mucins isolated from the human colon and from three human colonic adenocarcinoma cell lines: two with goblet cell‐like (LS174T and T84) and one with absorptive cell‐like morphology (Caco‐2). By Northern blot analysis the intestinal mucin genes MUC2 and MUC3 were constitutively expressed by confluent LS174T and Caco‐2 cells, whereas T84 cells only transcribed MUC2 and not MUC3 mRNA. 3H‐glucosamine and 3H‐threonine metabolically labeled proteins separated as high Mr mucins in the void (Vo > 106 Da) of Sepharose‐4B column chromatography and remained in the stacking gel of SDS‐PAGE as depicted by fluorography. All mucin preparations contained high amounts of N‐acetyl‐glucosamine, galactose, N‐acetyl‐galactosamine, fucose and sialic acid, saccharides typical of the O‐linked carbohydrate side chains. Mucin samples from the human colon and from LS174T and Caco‐2 cells inhibited E. histolytica adherence to Chinese hamster ovary cells, whereas mucins from T84 cells did not. These results suggest that genetic heterogeneity and/or posttranslational modification in glycosylation of colonic mucins can affect specific epithelial barrier function against intestinal pathogens.
Host Cell and Malarial Targets for Docetaxel (Taxotere™) during the Erythrocytic Development of Plasmodium falciparum
Authors: Sinou Veronique , Boulard Yves , Grellier Philippe , Schrevel Joseph
Published: May 2007

The microtubular stabilizing agent docetaxel (Taxotere™) is known to inhibit the intraerythrocytic development of Plasmodium falciparum. To investigate the mechanism(s) of inhibition, we analyzed the structural organization of the mitotic spindle by immunofluorescence and electron microscopy. When 30 μM docetaxel was applied for five hours on ring forms, alterations in the mitotic spindles leading to abnormal nuclear divisions were observed. At the trophozoite‐ and schizont‐stage, docetaxel pulses prevent mitosis by stabilizing microtubular structures associated with the mitotic apparatus, giving abnormal spindles. However, this inhibition did not interfere with parasite DNA synthesis indicating the absence of a checkpoint that couples exit from mitosis with proper spindle assembly as observed in higher eukaryotic cells. In parallel, intraerythrocytic concentration of docetaxel was measured in parasitized erythrocytes, after incubation of cells with 3H‐docetaxel for five hours. It was found to be 14‐fold increased at the ring‐stage of infected erythrocytes compared to normal ones, 170‐fold increased at the trophozoite‐stage and 1,500‐fold increased at the schizont‐stage. Our data show that, even though the overall intracellular concentration of docetaxel is low in docetaxel‐pulsed rings, the agent might be sufficient to disturb the spindle organization. However, the existence of targets for docetaxel other than mitotic spindle microtubules. i.e. erythrocyte membrane components, could interfere with mitotic spindle formation
Immunocytochemical Identification of Spore Proteins in Two Microsporidia, with Emphasis on Extrusion Apparatus
Authors: Delbac Frederic , Duffieux Francis , David Danielle , Metenier Guy , Vivares Christian P.
Published: May 2007

Microsporidia can form small spores with a unique invasive apparatus featuring a long polar tube whose extrusion allows entry of infectious sporoplasm into a host cell. The reactivity of mouse polyclonal antibodies raised against sporal proteins from two microsporidian species belonging to different genera (Glugea atherinae and Encephalitozoon cuniculi) was studied by western blotting and indirect immunofluorescence. Whole protein antisera provided a few cross‐reactions relatable to some proteins of the spore envelope or polar tube. Ultrastructural immunocytochemistry with murine antibodies against protein bands separated by sodium dodecylsulphate polyacrylamide gel electrophoresis allowed the assignment of several proteins to the polar tube (34, 75 and 170 kDa in Glugea, 35, 55 and 150 kDa in Encephalitozoon). Antigenic similarities were detected for the Glugea 34 kDa and Encephalitozoon 35 kDa polar tube proteins. Species‐specific proteins were shown to be located in either the lamellar polaroplast of Glugea or the spore envelope of Encephalitozoon.
Learamoeba waccamawensis, N. G., N. Sp. (Heterolobosea: Vahlkampfiidae), a New Temperature‐Tolerant Cyst‐Forming Soil Amoeba
Authors: Sawyer Thomas K. , Nerad Thomas A. , Cahoon Lawrence B. , Nearhoof Janice E.
Published: May 2007

Soil from a roadside ditch at Lake Waccamaw, North Carolina, was tested for cyst‐forming free‐living amoebae, and water from the same ditch was tested for fecal coliform bacteria. Soil samples incubated at room temperature (21‐23° C) yielded Acanthamoeba polyphaga, Amoeba sp., Hyperamaeba sp., Mayorella penardi. Naegleria gruberi, Naegleria minor, and unidentified ciliates, testaceans and slime molds. Incubation at 37‐39° C yielded Acanthamoeba jacobsi, Platyamoeba schaefferi, and a new amoeba to be described herein. Fecal contamination of the ditch was confirmed by a direct membrane filtration technique that yielded a mean of 1,410 + 134 bacteria/ ml. The new amoeba is assigned to the class Heterolobosea Page & Blanton, 1985 on the basis of promitotic nuclear division, and a flagellated stage with a cytostome as seen in the genus Tetramitus. Amoebae studied in hanging drop preparations were flattened and irregular as described for the genus Stachyamoeba in the family Gruberellidae but changed to a lobose cylindrical form as described for species of Vahlkampfia in the family Vahlkampfiidae. A new genus and species, Learamoeba waccamawensis, is proposed for the amoeba described herein.
Entamoeba dispar: infrastructure, Surface Properties and Cytopathic Effect
Authors: Espinosa‐Cantellano Martha , González‐Robles Arturo , Chávez Bibiana , Castañón Guadalupe , Argüello Carlos , Lázaro‐Haller Amparo , Martínez‐Palomo Adolfo
Published: May 2007

The cytological features of Entamoeba dispar, recently recognized by biochemical and molecular biology criteria as a distinct species, were compared to those of Entamoeba histolytica. When cultured under axenic conditions, living trophozoites of E. dispar strain SAW 760RR clone A were more elongated in form, had a single frontal pseudopodium, and showed a noticeable uroid. In sections of E. dispar trophozoites stained with Toluidine blue, characteristic areas of cytoplasmic metachromasia were seen due to the presence of large deposits of glycogen, seldom found in E. histolytica strain HM1:IMSS. Under the light microscope the periphery of the nucleus in E. dispar was lined by finer, more regularly distributed dense granules. With transmission electron microscopy the surface coat of E. dispar was noticeable thinner. In addition, E. dispar had a lower sensitivity to agglutinate with concanavalin A and a higher negative surface charge, measured by cellular microelectrophoresis. The cytopathic effect of E. dispar was much slower, analyzed by the gradual loss of transmural electrical resistance of MDCK epithelial cell monolayers mounted in Ussing chambers. Whereas in E. histolytica phagocytosis of epithelial cells plays an important role in its cytopathic effect, E. dispar trophozoites placed in contact with MDCK cells showed only rare evidence of phagocytosis. The results demonstrate that the morphology of E. dispar is different to that of E. histolytica, both at the light microscopical and the ultrastructural levels. In addition, they show that E. dispar in axenic culture has a moderate cytopathic effect on epithelial cell monolayers. However, when compared to E. histolytica, the in vitro lytic capacity of E. dispar is much slower and less intense.
Effect of Conditioned Media from Chicken and Turkey Intestinal Cell Cultures on Invasion by Sporozoites of Three Species of Avian Coccidia
Authors: Augustine Patricia C. , Jenkins Mark C.
Published: May 2007

The effect of conditioned media from cultures of turkey and chicken intestinal cells on cellular invasion by sporozoites of avian Eimeria species was examined in vitro. Media conditioned by the growth of cells from the ceca, mid‐intestine (area of the yolk stalk diverticulum), and duodenal loop were examined for their ability to enhance invasion. Conditioned medium from cultures of turkey cecal cells significantly enhanced invasion by the turkey coccidia Eimeria adenoeides, by 2.4‐fold, and E. meleagrimitis, by 2.2‐fold, as compared with invasion in the presence of control medium. Conditioned medium from mid‐intestinal cell cultures enhanced invasion by the two coccidial species by 2.0‐ and 2.1‐fold, respectively. The enhancement occurred with conditioned media from early (1) as well as later (11) passages of cells. This suggests that the enhancing factor was produced by fibroblast‐like cells, the predominant cell type at both early and late passages, and not by epithelial‐like cells that had disappeared by the first or second passage. Additionally, conditioned media from cultures of chicken cecal and duodenal loop cells significantly enhanced invasion by the turkey cecal coccidium, E. adenoeides, (1.7‐ and 1.6‐fold, respectively). This was less enhancement than was caused by the turkey cell conditioned media. Heat treatment (56° C for 45 min) of conditioned media failed to alter the effect on invasion. Neither the turkey or chicken cecal cell media nor conditioned media from any other chicken intestinal cell cultures enhanced invasion by E. tenella, the chicken cecal coccidium. Although morphologically dissimilar when they were first plated, the gross appearance and growth of the turkey and chicken cells when conditioned media was collected was comparable.
Insulin‐like Growth Factor‐I Induces Phosphorylation in Leishmania {Leishmania) mexicana Promastigotes and Amastigotes
Authors: Gomes Cláudia M. C. , Monteiro Hugo P. , Gidlund Magnus , Corbett Carlos E. P. , Goto Hiro
Published: May 2007

Protein phosphorylation controls major steps of proliferation and differentiation in eukaryotic cells. However there are few studies done in protozoa particularly when being triggered by external stimuli. In this paper we have examined the tyrosine‐ and serine/threonine‐phosphorylated proteins in both promastigote and amastigote‐like forms of Leishmania (Leishmania) mexicana stimulated with insulin‐like growth factor (IGF)‐I. Stimulation with IGF‐I induces major tyrosine phosphorylation of a 185‐kDa protein in promastigotes and 60‐ and 40‐kDa proteins in amastigotes. Analysis of total phosphorylation revealed additional sets of phosphorylated proteins: a 110‐kDa protein band in promastigotes and two other proteins of 120 and 95 kDa in the amastigote‐like forms. To further analyze the IGF‐I‐mediated response we compared it with the phosphorylation pattern obtained with a known inducer of protein kinase C, phorbol myristate acetate. This analysis showed overlapping phosphorylation of most of the proteins but mainly of the 185‐ and 110‐kDa proteins in the promastigotes and the 95‐. 60‐ and 40‐kDa proteins in the amastigote‐like forms. We thus conclude that there are phosphorylation‐dependem pathways in Leishmania parasites induced by IGF‐I that are stage‐specific.
Invention and Mystery in Hypotrich DNA1
Authors: Prescott David M.
Published: May 2007

ABSTRACT “The capacity to blunder slightly is the real marvel of DNA. Without this special attribute, we would still be anaerobic bacteria and there would be no music.” Lewis Thomas3

Hypotrichs have evolved extraordinary ways of organizing, manipulating, and replicating the DNA in their micronuclear and macronuclear genomes. Short macronuclear DNA molecules containing single genes are created by excision from chromosomes, accompanied by massive elimination of the germline DNA sequences between genes. Germline genes themselves are interrupted by multiple noncoding segments called internal eliminated segments, or IESs, that divide genes into multiple macronuclear‐destined segments, or MDSs. The functional significance of this organization is unknown. Over evolutionary time IESs accumulate mutations rapidly are inserted into or excised from genes, and shift position along DNA molecules. MDSs are ligated to create functional genes when IESs are spliced out of micronuclear DNA during macronuclear development. MDSs in some germline genes are in scrambled disorder and become unscrambled in association with IES elimination. Replication of DNA in the macronucleus is accomplished by organization of replication enzymes and factors into a structure that sweeps through the macronucleus to replicate the many millions of gene‐sized DNA molecules. The significance of many of the bizarre DNA phenomena in the evolutionary/functional success of hypotrichs is still unclear.
Infraciliary Bands in the Rumen Ophryoscolecid Ciliate Ostracodinium gracile (Dogiel, 1925), Observed by Light Microscopy
Authors: Ito Akira , Imai Soichi
Published: May 2007

ABSTRACT Morphological features of the rumen ciliate Ostracodinium gracile (Dogiel, 1925) are described from pyridinated silver carbonate‐impregnated specimens. Ostracodinium gracile has a characteristic arrangement of infraciliary bands not present in other ophryoscolecid ciliates. Buccal infraciliature is composed of three polybrachykineties. The adoral polybrachykinety does not completely encircle the circumference of the vestibular opening, but arches ventrally from its right to left side. The dorsoadoral polybrachykinety extends laterally along the dorsal side of the vestibular opening. The vestibular polybrachykinety extends along the dorsal wall of the long tubular vestibulum. Dorsal infraciliature consists of the dorsal polybrachykinety that extends laterally along the dorsal side of the body. During binary fission, four primordia, that is ventral, right, left, and dorsal primordia, form in the stomatogenic field and develop into the adoral, dorsoadoral, vestibular, and dorsal polybrachykineties of the opisthe. respectively.
Intracellular Ca2+ Homeostasis in Trypomastigotes of Trypanosoma cruzi
Authors: Zhang Hong Shan , McDonald Thomas V. , Tanowitz Herbert B. , Wittner Murray , Weiss Louis M. , Bilezikian John P. , Morris Stephen A.
Published: May 2007

ABSTRACT Trypomastigotes of Trypanosoma cruzi maintain an intracellular Ca2+ concentration([Ca2+]i) of 64 ± 30 nM. Equilibration of trypomastigotes in an extracellular buffer containing 0.5 mM [Ca2+]o (preloaded cells) increased [Ca2+]i < 20 nM whereas total cell Ca2+ increased by 1.5 to 2.0 pmole/cell. This amount of Ca2+ would be expected to increase [Ca2+]i to > 10 μM suggesting active sequestration of Ca2+. We tested the hypothesis that maintenance of [Ca2+]i involved both the sequestration into intracellular storage sites and extrusion into the extracellular space. Pharmacological probes known to influence [Ca2+]i through well characterized pathways in higher eukaryotic cells were employed. [Ca2+], responses in the presence or absence of [Ca2+]o were measured to asses the relative contribution of sequestration or extrusion processes in [Ca2+]i homeostasis. In the presence of 0.5 mM [Ca2+]o, the ability of several agents to increase [Ca2+]i was magnified in the order ionomycin ⋙ nigericin > thapsigargin > monensin > valinomycin. In contrast, preloading markedly enhanced the increase in [Ca2+], observed only in response to monensin. Manoalide, an inhibitor of phospholipase A2, enhanced the accumulation of [Ca2+]i due to all agents tested, particularly ionomycin and thapsigargin. Our results suggest that sequestration of [Ca2+]i involved storage sites sensitive to monensin and ionomycin whereas extrusion of Ca2+ may involve phospholipase A2 activity. A Na+/Ca2+ exchange mechanism did not appear to contribute to Ca2+ homeostasis.