bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzyme Cytochemistry of the Alveolar Sacs and Golgian‐Like Cisternae in the Ciliate Ichthyophthirius multifiliis
Authors: LOBO‐DA‐CUNHA A. , AZEVEDO C.
Published: May 2007

In the cell cortex of the parasitic ciliate Ichthyophthirius multifiliis different kinds of cisternae were observed: the alveolar sacs, thick membrane cisternae and the endoplasmic reticulum. The thick membrane cisternae possess coated dilated rims and sometimes could be observed close to the endoplasmic reticulum. Using cytochemical techniques acid phosphatase, thiamine pyrophosphatase and nucleoside diphosphatase activities were detected in the thick membrane cisternae and in the alveolar sacs of trosphozoites. In the endoplasmic reticulum acid phosphatase activity was not detected and only very small amounts of thiamine pyrophosphatase and nucleoside diphosphatase reaction product were observed. After exit from the host, a reduction in acid phosphatase activity was evident in the alveolar sacs. At theront stage acid phosphatase activity is absent from these structures. However, high thiamine pyrophosphatase and nucleoside diphosphatase activities remain in the alveolar sacs during the whole life cycle. On the other hand, acid phosphatase, thiamine pyrophosphatase and nucleoside diphosphatase activities were detected in thick membrane cisternae of theronts. Based on the morphological aspects and enzymatic content the thick membrane cisternae of the cell cortex are designated as golgian‐like cisternae. The cytochemical results point out a relationship between the alveolar sacs and the Golgi complex.
The Effect of Dietary Sterol on the Activity of Fatty Acid Desaturases Isolated from Tetrahymena setosa
Authors: KOLL MARYANNE , ERWIN JOSEPH A.
Published: May 2007

Tetrahymena setosa has a nutritional requirement for micro amounts of sterol, a requirement which is also satisfied by relatively large amounts of either intact phospholipids or a mixture of unsaturated fatty acids normally found in these ciliates. Three microsomal fatty acyl‐CoA desaturases have been isolated from T. setosa and partially characterized. These enzymes which can account for the formation of the majority of the ciliate's unsaturated fatty acids, include: a Δ9, a Δ12 and a Δ6 desaturase which catalyze the transformation of stearoyl‐CoA to oleic acid, of oleoyl‐CoA to linoleic acid and of linoleoyl‐CoA to ϒ‐linolenic acid, respectively. The stearoyl CoA desaturase required NAD (or NADP), ATP and free CoA; the Δ6 and Δ12 desaturases required NADP, but not ATP or CoA. Cellular levels of the three desaturases were highest in mid‐logarithmic phase cells and lowest in stationary phase cells. In order to determine if there was a relationship between the sterol requirement and the ability of the organism to desaturate, T. setosa was grown in a synthetic medium supplemented with either cholesterol or a phospholipid which permits growth in the absence of cholesterol, or with both phospholipid and cholesterol. Cells grown with phospholipid alone had only half as much stearoyl‐CoA and oleoyl‐CoA desaturase activity as cells of identical culture age grown either on cholesterol alone or on cholesterol plus phospholipid.
A Comparative Analysis of the Morphology and Morphogenesis of Gonostomum strenua (Engelmann, 1862) (Ciliophora, Hypotrichida) and Related Species
Authors: SONG WEIBO
Published: May 2007

The morphology and morphogenesis of the hypotrichous ciliate, Gonostomum strenua, found in the soil of a hill in Qingdao (Tsingtao, 36°08’N, 120°43’E), People's Republic of China is described. Some characteristics (organization of the frontoventral cirral rows, origin of the primary primordium and arrangement of the marginal as well as transverse cirri) are sufficiently different from a closely related species Gonostomum affine to suggest that it is a separate species, though its body shape, nucleus and buccal apparatus are very similar to that of G. affine. A comparison of the infraciliatures of the two species is necessary since morphological characteristics alone are sometimes insufficient for species separation.
NACM, A Cytopathogenic Protein from Naegleria gruberi, EGs; Purification, Production of Monoclonal Antibody, and the Immunoidentification of a Product that Develops in NACM‐treated Vertebrate Cell Cultures
Authors: DUNNEBACKE THELMA H. , DIXON JONATHAN S.
Published: May 2007

The story of NACM involves the discovery of a deleterious response of cultured vertebrate cells to a component in cell‐free lysates prepared from free‐living amebae of the genus Naegleria; hence the acronym NACM derived from Naegleria ameba cytopathogenic material. The cellular reaction is the basis for the biological assay that has been fundamental in the study of the action of NACM in a variety of cell cultures. It also has been used in the determination of the physical characteristics, and to monitor the behavior of NACM during isolation procedures. All findings are compatable with the conclusion that NACM is a 35 Kd protein. Recently, the use of monoclonal antibodies (MAbs) prepared to amebae‐derived purified NACM have resulted in visual display of a product that develops exclusively in NACM‐treated cells. That cellular product is shown to be related to NACM by its immunostaining reaction with the MAb; the relationship of the MAb with NACM is demonstrated by its ability to neutralize the biological activity of NACM, and as an immunostain, to react with purified fractions of NACM and with whole amebae. The combination of these observations describes a unique set of interactions in which NACM, an amebic component, identified as a protein, has characteristics of an infectious agent when introduced into cultures of avian and mammalian cells.
Genes of Acanthamoeba: DNA, RNA and Protein Sequences (A Review)1
Authors: BYERS THOMAS J. , HUGO ERIC R. , STEWART VALERIE J.
Published: May 2007

This review summarizes knowledge about the structure of nuclear genes and mitochondrial DNA in Acanthamoeba. The information about nuclear genes is derived from studies of DNA, RNA and protein sequences. The genes considered are those for 5S, 5.8S and 18S rRNA, actin I, profilins Ia/b and II, myosins IB, IC and II, and calmodulin. All of the sequences show strong similarities to comparable sequences from other organisms. Introns have been found in the actin and myosin genes. The location of the actin intron is unique, but many of the myosin introns occur at the same sites as introns in myosins of other organisms. Sequence comparisons, especially of 5S and 5.8S rRNA and actin, support previous evidence, based primarily on 18S rRNA, that Acanthamoeba genes are at least as closely related to those of higher plants and animals as they are to various other protistan genera. The functional organization of the promoter region for the nuclear rDNA transcription unit has been studied extensively, but there is a need for information about the functional organization of regulatory sequences for other genes. Restriction fragment length profile (RFLP) studies of mitochondrial DNA reveal relatively high levels of overall sequence diversity, but information on the structure and function of individual genes is needed. The RFLP appear to have potential as tools for taxonomic studies of this genus.
Regulation of Ornithine decarboxylase activity in the Growth cycle of Tetrahymena thermophila
Authors: EICHLER WOLFGANG
Published: May 2007

Cells of the Ciliated Protozoan Tetrahymena Theermophila, grown in proteose peptone medium to late logarithmic phase, harvested by centrifugation, and resuspended in fresh medium to almost the same cell density, underwent one more divison cycle within 5 h after inoculation, thereafter being definitely in full stationary phase. This growth cycle proved to be a useful tool to investigate the activation and deactivation of ornithine decarboxylase ODC1 in Tetrahymena: In late logarithmic phase the cells contained a very low specific activity of ODC of 3 nmol Co2.h‐1. mg‐1 in the soluble protein fraction. After growth stimulation the cells the activity was increased up to 100‐fold within 1 h. This high activity was maintained for about 5 h‐ about as long as divison activity—then rapidly declined with a half life time(t1/2 of about 15 min to the original low level.

Inhibition assays with cycloheximide and actionomycin D revealed that: i. the rapid increase of ODC activity was biphasic with one component of translation ofpreexisting mRNA and one component of translation of newly transcribed mRNA; ii. the1/2 of the mRNA of ODC was estimated to be about 2 h; iii. inhibition of protein biosynthesis before ODC inactivation at 5 h caused a decrease of ODC with t1/2 of 55 min instead of 15 min.

These findings suggest that ODC activity in Tetrahymena is regulated on both leavels: transcriptition and translation and translation and by an inactivating protein factor which is regulated at the level of biosynthesis.
Temperature‐Sensitive Responses in Blepharisma
Authors: MATSUOKA TATSUOMI , MAMIYA RYUSUKE , TANEDA KOJI
Published: May 2007

Temperature sensitivity of Blepharisma cultured at 23°C was investigated in a temperature range between 18.5°C and 33.5°C. The cells accumulated in an optimal temperature (ca. 27°C) region when they were placed in a chamber with a temperature gradient, although a certain population of the cells accumulated at much higher temperatures. The quantitative analysis of behavioral responses exhibited by the cells revealed that three types of thermal response were responsible for thermoaccumulation of the cells in an optimal temperature: (1) an increase in the frequency of thermophobic response in the cells swimming away from the optimal temperature region; (2) acceleration of forward swimming velocity of the cells swimming toward the optimal temperature region; and (3) higher frequency of spontaneous ciliary reversal of the cells in higher temperature regions.
Granulocyte‐Macrophage Colony‐Stimulating Factor is a Growth‐Factor for Promastigotes of Leishmania mexicana amazonensis
Authors: CHARLAB ROSANE , BLAINEAU CHRISTINE , SCHECHTMAN DEBORAH , BARCINSKI MARCELLO A.
Published: May 2007

ABSTRACT. In this paper we show that murine lung conditioned medium (LCM) displays, in addition to its already described colony‐stimulating activity on bone marrow cells, a potent growth‐stimulating activity on promastigotes of Leishmania mexicana amazonensis. Immunoprecipitation of LCM with an antibody specific for murine granulocyte‐macrophage colony stimulating factor (GM‐CSF) abrogates both activities, indicating that the leishmanial growth‐promoting activity is due to the presence of GM‐CSF on LCM. Furthermore, recombinant GM‐CSF (rGM‐CSF) added to the culture medium or to the immunoprecipitated LCM is able to respectively induce or to partially recover the growth‐promoting activity of the LCM. Sequential in vitro passages of the parasite induces a progressive loss of sensitivity to the growth‐factor. Parasite forms recently collected from lesions are significantly more responsive to the growth‐factor than forms already adapted to grow in culture. Since it has been shown that several different microorganisms display receptors for vertebrate‐like hormones and that GM‐CSF is able to enhance a cutaneous leishmanial lesion, our results permit us to raise the hypothesis that a direct interaction between a host‐derived hormone and a pathogenic microorganism can be of importance in defining the fate of an infection. The fact that GM‐CSF is produced by cells that actively participate in a leishmanial infection (T‐lymphocytes and macrophages) reinforces our hypothesis.
Revision of the Genus Askenasia Blochmann, 1895, with Proposal of Two New Species, and Description of Rhabdoaskenasia minima N. G., N. Sp. (Ciliophora, Cyclotrichida)
Authors: KRAINER KARL‐HEINZ , FOISSNER WILHELM
Published: May 2007

ABSTRACT. The planktonic ciliate genus Askenasia Blochmann, 1895 is reviewed and the new genus Rhabdoaskenasia n. gen. is established. Askenasia is characterized by three circumferential kinety belts and a circumoral wreath of paired argyrophilic granules without recognizable cilia and nematodesmata. A “brush” is absent. Askenasia apparently lacks the key characters of the Haptorida and is thus transferred to the Cyclotrichida, family Mesodiniidae. Rhabdoaskenasia differs from Askenasia in having single files of basal bodies in all kinety belts and club‐shaped extrusomes. It possesses a circumoral kinety composed of dikinetids from which nematodesmata originate, forming a distinct rhabdos. Although very similar to Askenasia in its general appearance, R. minima n. sp. could belong to another order. Based on an extensive review of the literature and on silver impregnated specimens the following Askenasia species are recognized and described in detail: A. volvox (Eichwald, 1852) Kahl, 1930, A. stellaris (Leegaard, 1920) Kahl, 1930, A. acrostomia n. sp., and A. chlorelligera n. sp. Askenasia faurei Kahl, 1930 and A. humilis Gajewskaja, 1928 are transferred to the genus Cyclotrichium: C. faurei (Kahl, 1930) n. comb., C. humilis (Gajewskaja, 1928) n. comb. The systematic position of the genus Askenasia is discussed and keys to the genera of the Mesodiniidae and to the species of Askenasia are provided.
Analysis of Pneumocystis carinii Cyst Wall I. Evidence for an Outer Surface Membrane
Authors: De STEFANO JAMIE A. , CUSHION MELANIE T. , SLEIGHT RICHARD G. , WALZER PETER D.
Published: May 2007

ABSTRACT. It has long been thought that the cyst form of Pneumocystis carinii, which can resist host defenses and antimicrobial drugs, is responsible for relapses of P. carinii pneumonia. The thick wall of the cyst is immunogenic and rich in glucosyl/mannosyl and N‐acetyl‐D‐glucosamine residues. In this study we have demonstrated the presence of a hitherto unreported outer membrane in the cyst wall of P. carinii. This membrane was detected by a combination of techniques, including transmission electron microscopy, freeze‐fracture electron microscopy, and membrane labeling with fluorescent lipid analogs following treatment of P. carinii cysts from infected rats for 30 min with Zymolyase, a β‐1–3 glucanase. As in gram‐negative bacteria and blue‐green algae, this 2nd membrane may have an important role in osmoregulation and nutrient utilization; it may also mediate the interaction of P. carinii with its host and serve as a target for drug therapy.
Rumen Ciliate Protozoa in Ohio White‐tailed Deer (Odocoileus virginianus)
Authors: DEHORITY BURK A.
Published: May 2007

ABSTRACT. Rumen contents were obtained from 23 white‐tailed deer (Odocoileus virginianus), located in the eastern portion of central Ohio. Samples were taken during late fall and winter over a 4‐yr period, 1986–1990. Protozoan numbers ranged from 0.002 to 7.25 × 106 per ml of rumen contents, with a mean of 2.96 × 106. Six deer had protozoan concentrations higher than any values previously reported in ruminants. In all 23 animals, Entodinium dubardi was the only ciliate protozoan species present.
Plasmodium Sporozoite Interactions with Macrophages In Vitro: a Videomicroscopic Analysis
Authors: VANDERBERG JEROME P. , CHEW SERENA , STEWART MICHAEL J.
Published: May 2007

ABSTRACT. Studies of in vitro interactions between Plasmodium berghei sporozoites and peritoneal macrophages from mice and rats were performed. A videomicroscopic analysis was made of interactions observed by phase‐contrast microscopy. Our results showed a diversity of dynamic interactions between sporozoites and macrophages that included no interaction, surface interaction without sporozoite interiorization, active sporozoite penetration, active penetration with subsequent sporozoite escape, macrophage destruction, and the formation of “tethers” or web‐like structures by sporozoites that had actively invaded macrophages. Sporozoites are thus clearly capable of actively invading host macrophages and are not restricted to being phagocytosed for interiorization. The formation of “tethers” by the moving sporozoite might function in vivo by anchoring the sporozoite to the cells lining the lumen of the liver sinusoid. Active sporozoite motility appears to be a functional phenomenon involved in sporozoite invasion of host liver cells.
Degradation, Recycling, and Shedding of Trypanosoma brucei Variant Surface Glycoprotein
Authors: SEYFANG ANDREAS , MECKE DIETER , DUSZENKO MICHAEL
Published: May 2007

ABSTRACT. Trypanosoma brucei bloodstream forms express a densely packed surface coat consisting of identical variant surface glycoprotein (VSG) molecules. This surface coat is subject to antigenic variation by sequential expression of different VSG genes and thus enables the cells to escape the mammalian host's specific immune response. VSG turnover was investigated and compared with the antigen switching rate. Living cells were radiochemically labeled with either 125I‐Bolton‐Hunter reagent or 35S‐methionine, and immunogold‐surface labeled for electron microscopy studies. The fate of labeled VSG was studied during subsequent incubation or cultivation of labeled trypanosomes. Our data show that living cells slowly released VSG into the medium with a shedding rate of 2.2 ± 0.6% h−1 (t1/2= 33 ± 9 h). In contrast, VSG degradation accounted for only 0.3 ± 0.06% h−1 (t1/2= 237 ± 45 h) and followed the classical lysosomal pathway as judged by electron microscopy. Since VSG uptake by endocytosis was rather high, our data suggest that most of the endocytosed VSG was recycled to the surface membrane. These results indicate that shedding of VSG at a regular turnover rate is sufficient to remove the old VSG coat within one week, and no increase of the VSG turnover rate seems to be necessary during antigenic variation.
Actinocephalus carrilynnae N. Sp. (Apicomplexa: Eugregarinorida) from the Blue Damselfly, Enallagma civile (Hagen)
Authors: RICHARDSON SARAH , JANOVY J.
Published: May 2007

ABSTRACT. Actinocephalus carrilynnae, a new species of actinocephalid gregarine, is described from the blue damselfly, Enallagma civile. Trophozoites are unpaired, lying between the host's gut epithelium and peritrophic membrane, and attain a maximum length of at least 1,700 μm. Protomerites are subspherical. Epimerites are globular, hemispherical with stub‐shaped or truncated cone‐shaped projections and are attached to the protomerite by means of a fluted stalk. Protomerite‐deutomerite length ratio is 0.12 and relatively constant regardless of trophozoite length. Gametocysts are subspherical, 270–280 μm in diameter, and undergo sporogenesis in 24–36 h, dehiscing by rupture. Spores are biconical, slightly crescent‐shaped, and very uniform in size: 15 μm long and 4–5 μm wide. The parasite infects both adult and naiad hosts.
Detection of Glycogen‐Debranching System in Trophozoites of Entamoeba histolytica
Authors: WERRIES ECKHARD , FRANZ ALFRED , GEISEMEYER SIBYLLE
Published: May 2007

ABSTRACT. Homogenates of trophozoites of Entamoeba histolytica were shown to bring about the total degradation of glycogen while purified phosphorylase of the same source alone yielded a limit dextrin as end product. An enzyme system capable of debranching the limit dextrin was obtained from the 40,000 g pellet by extraction in aqueous medium, purified by gel filtration on Fractogel TSK HW‐55(F), and separated from phosphorylase by chromatography on Blue Sepharose CL‐6B and aminobutyl Agarose. The glycogen‐debranching system was purified 540‐fold to a state of homogeneity by criterion of disc‐gel electrophoresis. The purified enzyme was able to degrade glycogen‐limit dextrin in the presence of phosphorylase and exhibited activities of both amylo‐1,6‐glucosidase (EC 3.2.1.33) and 4‐α‐glucanotransferase (EC 2.4.1.25). Although amylo‐1,6‐glucosidase released glucose from a glycogen‐phosphorylase limit dextrin, transferase activity moved single glucose residues from the limit dextrin to 4‐nitrophenyl‐α‐glucoside yielding successively 4‐nitrophenyl‐α‐maltoside and 4‐nitrophenyl‐α‐maltotrioside that could be detected by HPLC. Native glycogen‐debranching system exhibited a relative molecular mass of Mr= 180,000 ± 10% by gel filtration and gel electrophoresis in both denaturing and nondenaturating conditions.
Amblyospora trinus N. Sp. (Microsporida: Amblyosporidae) in the Australian Mosquito Culex halifaxi (Diptera: Culicidae)
Authors: BECNEL JAMES J. , SWEENEY A. W.
Published: May 2007

ABSTRACT. A new species of Amblyospora, a parasite found in wild populations of the predacious Australian mosquito Culex halifaxi, was investigated with light and electron microscopy. This species was found to be heterosporous with two concurrent sporulation sequences in the host larvae, both arising from diplokaryotic meronts and ending with haploid spores. One sequence was dominant and involved meiosis to produce eight thick‐walled, broadly oval meiospores in a sporophorous vesicle (SV). The other sequence involved nuclear dissociation to produce lanceolate, thin‐walled spores in a subpersistent SV. Horizontal transmission to the mosquito host, by one or both of two distinctly different pathways (one via an intermediate host, the other by cannibalism of infected individuals) and by vertical transmission, are postulated but have not been demonstrated. A new species, Amblyospora trinus, is proposed and its affinities to other heterosporous microsporidia in mosquitoes are discussed.
Development of Amblyospora campbelli (Microsporida: Amblyosporidae) in the Mosquito Culiseta incidens (Thomson)
Authors: DICKSON DAVID L. , BARR A. RALPH
Published: May 2007

The complete life cycle of Amblyospora campbelli (Kellen and Wills, 1962) (Microsporida: Amblyosporidae) requires a two‐host system involving the mosquito host, Culiseta incidens (Thomson), and an obligatory intermediate copepod host. The parasite has dimorphic spore development producing meiospores (haploid condition) and binucleated spores (diploid condition), either as an exclusive infection or simultaneously (within females only). This is the 1st known report of concurrent spore development within an adult mosquito host, and, therefore, shows the Amblyospora campbelli system to be uniquely different from other Amblyospora spp. cycles previously described. The significance of dimorphic spore development is discussed. In females, diplokaryotic meronts may invade oenocytes, causing a benign‐type of infection. A blood‐meal is required to initiate sporulation of the binucleate spore. The binucleate spore contains the sporoplasm involved in transovarial transmission. A 2nd sporulation sequence, primarily in adipose tissue, may involve both males and females. In this sequence, repeated merogonic division greatly increased the density of diplokaryotic meronts and generally involved most of the body of the host. Production of meiospores, unlike that for the binucleate spore, appeared to be spontaneous (i.e. no obligatory blood meal). Survivorship of male and female larval mosquitoes was nearly equal. Adult females spread the parasite in three ways: transovarial, transovum, and by meiospore deposition.
Analysis of Chlamydomonas reinhardtii Histones and Chromatin
Authors: MORRIS RODNEY L. , KELLER LAURA R. , ZWEIDLER ALFRED , RIZZO PETER J.
Published: May 2007

Chromatin spreads made from isolated nuclei of the unicellular green alga Chlamydomonas reinhardtii show the beaded fibers typical of eukaryotic polynucleosomes. Micrococcal nuclease digestions confirmed the presence of nucleosomes with a repeat length of 189 base pairs, essentially the same as typical mammalian cells. Basic nuclear proteins extracted from isolated nuclei or chromatin with 1 M calcium chloride and 0.3 M hydrochloric acid are resolved into seven major components by electrophoresis in the presence of sodium dodecyl sulfate (SDS). These seven components were subjected to qualitative peptide mapping with V8 protease on SDS gels for comparison with the major histone components of calf thymus. Finally, the C. reinhardtii basic nuclear proteins were fractionated by reversed phase high performance liquid chromatography and their amino acid composition determined. From these studies, we conclude that C. reinhardtii has a full complement of the five histones with properties very similar to those of both higher animals and higher plants.
Cytopathic Action of Naegleria fowleri Amoebae on Rat Neuroblastoma Target Cells
Authors: MARCIANO‐CABRAL FRANCINE , ZOGHBY KATHY L. , BRADLEY S. GAYLEN
Published: May 2007

The axenically cultured, weakly pathogenic Naegleria fowleri LEE and the highly pathogenic, mouse passaged N. fowleri LEEmp are cytopathic for B103 rat nerve cells in culture. Cytopathogenicity was measured by release of radiolabeled rubidium or radiolabeled chromium from B103 target cells. Cytopathogenicity was time‐dependent for up to 18 h and dependent upon amoebae effector to nerve cell target ratios of less than 1:1. Release of51 Cr from B103 cells by either LEE or LEEmp amoebae was enhanced by addition of calcium or magnesium to medium free of these divalent cations but the ion‐channel inhibitor, verapamil, or the ionophore A23187 and phorbol myristate acetate did not alter release of 51 Cr from B103 cells cocultured with the amoebae. Cycloheximide or actinomycin D impaired release of 51 Cr from B103 target cells injured by either LEE or LEEmp amoebae. Both strains of amoebae were fractionated by glass bead disruption and high speed centrifugation into membrane and soluble fractions. Each fraction was incubated with either 86Rb or 51 Cr labeled nerve cells. The membrane fraction from LEEmp was more active than the soluble fraction in facilitating rubidium and chromium release. In contrast, the soluble fraction from LEE was more active than the membrane fraction in facilitating rubidium release from radiolabeled target cells. The sequential release of 86Rb and 51 Cr from target cells rather than the simultaneous release of the two isotopes indicates that target cell death is due to the release of ions followed later by the release of large macromolecules. The results indicate that N. fowleri amoebae injure nerve cells by two alternate mechanisms, trogocytosis or contact‐dependent lysis.
Nocodazole‐Resistant Mutants in Paramecium
Authors: TORRES ANTONIO , ROSSIGNOL MICHÈLE , BEISSON JANINE
Published: May 2007

The effect of the microtubule inhibitor nocodazole was studied on Paramecium and shown to arrest cell multiplication, depolymerize the internal microtubule network, and block the development of macro‐ and micronuclear spindles and of the cytospindle (a cortical microtubule array assembled during division). After ultraviolet mutagenesis, three mutants resistant to nocodazole, that is capable of continued growth in the presence of the drug, were isolated and shown to correspond to three nonallelic single‐gene nuclear mutations. One (nocr‐1) is semidominant while the other two (nocr‐2 and nocr‐3) are recessive. Cytological and physiological studies of nocodazole's effects on the mutants demonstrate that their resistance is due neither to a lack of drug penetration nor to its degradation since, in each mutant in the presence of the drug, some microtubule networks are normal or subnormal while others remain affected as in wild‐type cells. These are the first mutants resistant to microtubule depolymerizing drugs obtained in ciliates that provide a new tool for studying the assembly and dynamics of the diverse microtubule arrays in this type of organism.
PCR Amplification of Tetrahymena rDNA Segments Starting with Individual Cells
Authors: ORIAS EDUARDO , HASHIMOTO NAOKO , CHAU MIU‐FUN , HIGASHINAKAGAWA TORU
Published: May 2007

To facilitate studies of rDNA molecular genetics in Tetrahymena thermophila, we attempted the detection of polymorphisms in the nontranscribed spacers (NTSs) using polymerase chain reaction (PCR), starting with minute amounts of DNA. The targeted polymorphic regions are 85% adenine‐thymine (AT). We found conditions of efficient and specific in vitro amplification of targeted segments in the replication domain of the 5′NTS and in the subtelomeric segment of the 3′NTS. The identity of the amplified segments was confirmed by restriction enzyme digestion and DNA sequence analysis. Digestion of the template DNA at restriction sites upstream and downstream of the targeted region increased the efficiency of amplification, presumably because the targeted segments are in a palindromic molecule. Starting from total cell DNA corresponding to as little as 0.03 picogram (equivalent to the DNA content of 0.003 cells or about 30 rDNA molecules), we observed the amplified band after agarose gel electrophoresis and ethidium bromide staining. The yield indicated more than 10‐billion‐fold amplification. Amplification of the subtelomeric fragment yielded homogeneous product of minimum possible length even though the telomeric‐specific primer can bind, at least initially, at a multiplicity of GGGGTT repeats. Amplified 5′NTS product also was detected in an ethidium‐bromide‐stained gel when PCR was started with a single cell.
The Fine Structure of the Cinctum of Ellobiophrya conviva (Ciliophora: Peritricha)
Authors: BRADBURY PHYLLIS CLARKE , CLAMP JOHN C.
Published: May 2007

Ellobiophrya conviva clasps tentacles of the bryozoan Bugula neritina with a ring‐like structure formed from aboral extensions of its body that taper into two slender arms. The tips of the arms overlap and join to form a unique organelle, the bouton. Each arm contains a massive myoneme that splays out at the bouton. The bouton consists of the cupped tips of the arms and a cavity, which is filled with dense homogeneous material. Long digitations containing longitudinal microtubules at their periphery project from the inner surface of the tip of each arm into the cavity. Deep folds of pellicle with pores opening into their depths line the wall of the cavity. Conventional kinetosomes are not visible in the bouton, but circular or elliptical arrays of microtubules are found at the bases of digitations. The nonfunctional scopula of the adult is in a depression enclosed by pellicular folds. The bouton is distant from the scopula, but its fine structure somewhat resembles it, supporting Chatton and Lwoff's hypothesis that the cinctal arms carry parts of the scopula at their tips. The fine structure of the cinctum supports their suggestion that the cinctal arms are homologous to the spasmonemes of vorticellid peritrichs.
On the Cytology and Fine Structure of the Neogregarine Syncystis aeshnae Tuzet and Manier, 1953 (Apicomplexa, Syncystidae)
Authors: LARSSON J. I. RONNY
Published: May 2007

The neogregarine Syncystis aeshnae Tuzet and Manier, 1953, was obtained from two species of dragonfly larvae, Aeshna grandis and Libellula quadrimaculata, collected in southern Sweden. Merogony, gamogony, and sporogony were observed in the adipose tissue, which was destroyed, and the haemocoele. Merozoites had a traditional apical complex. Gamonts associated in pairs did not unite conoid‐to‐conoid, and the border between gamonts was not found to break down. Each association produced 32 spores in bilobed gametocysts. Spores were elongate, oval, 4.0–5.8 × 8.0–10.0 μm in fixed and stained condition, each with 4+4 terminal and four equatorial thread‐like projections. The thick‐walled spore is considered the sporocyst. Species identification, ultrastructural cytology, and problems associated with using the terms “oocyst” and “sporocyst” are discussed.
Identification and Properties of Plateins, Major Proteins in the Cortical Alveolar Plates of Euplotes1
Authors: KLOETZEL JOHN A.
Published: May 2007

Morphogenesis of the ciliate cortex has been viewed as an attractive model system for studying the mechanisms behind the ordered assembly of subcellular structure. Based on the assumption that identifying protein components of the cortex would facilitate the study of cortical assembly, I have produced a number of monoclonal antibodies directed against components of the cortex of Euplotes aediculatus. Several of these antibodies react with the proteins comprising the alveolar plates. These thin polygonal scales, each enclosed within a flattened membranous sac (alveolus) just beneath the cell membrane, tightly abut in a confluent monolayer that appears to lend form and rigidity to the Euplotes cell cortex. Reactivity and specificity of these monoclonal antibodies for the alveolar plates was shown by immunofluorescence staining of whole‐cell preparations and of cryosections, and by immuno‐gold staining of thin sections by electron microscopy. On immunoblots of SDS‐PAGE separated whole‐cell extracts, the plate proteins are revealed as two to three closely spaced bands centered at an Mr of 97 kDa, and a larger relative at 125 kDa. Comparative peptide mapping reveals that the members of the 97‐kDa protein cluster are closely related. However, the 125‐kDa polypeptide varies significantly from the 97‐kDa members, and hence is not likely a synthetic precursor. Because bands of these Mr values are prominent in Coomassie blue‐stained gels of whole‐cell extracts, and are greatly enriched in purified cortical preparations, they likely represent the major proteins comprising the alveolar plates of E. aediculatus. I have proposed the name platein for this family of proteins.
Extracellular Calcium Concentration Affects Infectivity of Ichthyophthirius (Ciliophora) Theronts
Authors: EWING MARGARET S. , HEFLER CAROL , KOCAN KATHERINE M. , STEBLER ELAINE
Published: May 2007

Tomonts and their theront offspring of the hymenostomatid fish parasite Ichthyophthirius multifiliis were exposed to calcium levels from 0 to 0.8 mM Ca2+. The survival and reproductive rates of tomonts in the absence of extracellular calcium were not significantly different from rates of tomonts provided calcium. Theronts that developed in the absence of calcium, however, were not infective for Ictalurus punctatus even when the extracellular magnesium concentration was doubled. Theronts that developed in 0.10 mM Ca2+ were infective (0.77 trophonts/mm2 of pectoral fin) to essentially the same extent as theronts provided 0.33 mM Ca2+. Infectivity of those provided 0.8 mM Ca2+ was 1.79 trophonts/mm2 of fin, similar to that of theront controls. Theronts deprived of extracellular calcium as they developed contained significantly fewer secretory mucocysts than did theronts provided 0.1 to 0.8 mM Ca2+ although no significant differences among groups occurred with respect to abundance of crystalline or differentiating mucocysts. Theronts deprived of extracellular calcium also had swollen or enlarged mitochondria and abnormal crystalline mucocysts.
Geosmin As an Odorous Metabolite In Cultures of A Free‐Living Amoeba, Vannella Species (Gymnamoebia, Vannellidae)
Authors: HAYES SUZANNE J. , HAYES KEITH P. , ROBINSON BRET S.
Published: May 2007

ABSTRACT Geosim was identified as the cause of a distinct earthy/grassy odour detected in cultures of a free‐living amoeba, Vannella species. Volatile components of cell lysates were isolated and concentrated by the Closed Loop Stripping method. Capillary, gas chromatography/mass spectrometry was used to identify odorous compounds. Bacterial symbionts observed in the cytoplasm of the amoebae may be responsible for production of the geosmin. This appears to be the first report of odorous compounds associated with a free‐living protozoan and suggests that in some circumstances, Vannella sp. may contribute to taste and odour problems in drinking water.
Tetrahymena Thermophila: Growth In Synthetic Nutrient Medium In the Presence and Absence of Glucose
Authors: SZABLEWSKI L. , ANDREASEN P. HOVE , TIEDTKE A. , FLORIN‐CHRISTENSEN J. , FLORIN‐CHRISTENSEN M. , RASMUSSEN L.
Published: May 2007

ABSTRACT This report contains the newest directions for preparation of the synthetic nutrient medium for some Tetrahymena species that do not require lipids. In the standard medium T. thermophila. strains SB 210 and 281, multiply at 37°C with doubling times of around 2 h and at 26°C around 5 h. We have established multiplication rates as functions of variations in the composition of the medium. In media in which all components are present at one‐third of the normal concentrations and only the essential amino acids are included, growth and multiplication become sharply dependent on glucose in strain SB 281. Such media may be used for selection and enrichment of certain specified cell lines.
Comparative and Experimental Approaches to the Study of Microbial Food Webs
Authors: PACE MICHAEL L.
Published: May 2007

ABSTRACT The study of microbial food webs is dominated by field measurements of microbial standing stocks and rate processes and to a lesser extent by laboratory studies. These approaches reflect the concerns of microbial ecologists to assess accurately the capabilities of microorganisms and to compare microbial processes to other ecosystem parameters. These approaches have led to enormous advances in understanding microbial food webs. Reconciling our expanding knowledge with general questions about the significance and representation of microbial food webs in ecosystem studies requires additional approaches including comparative studies and field experiments. Comparative studies, analyses of microbial stocks or rates across a wide range of ecosystems, lead to quantitative models of microbial processes. These models facilitate testing of hypotheses at a very general level, allow the comparison of different stocks or rate processes across a gradient of systems, and detect unusual situations or outlier systems. Field experimental manipulations offer the advantages of working with intact natural communities, of direct evaluation of results with statistical methods, and of testing important qualitative hypotheses. Both comparative and field manipulation studies have led to important advances in the study of microbial food webs and should be expanded.
Gregarina niphandrodes N. Sp. (Apicomplexa: Eugregarinorida) from Adult Tenebrio molitor (L.) with Oocyst Descriptions of Other Gregarine Parasites of the Yellow Mealworm
Authors: CLOPTON RICHARD E. , PERCIVAL TAMARA J. , JANOVY JOHN
Published: May 2007

Gregarina niphandrodes, a new species of septate eugregarine, is described from the adult mealworm, Tenebrio molitor. Measurements given are means in μm. Gamonts in association. Nuclear diameter consistent, 35.5. Primite: protomerite hemispherical; length 59.5; width 91.2; deutomerite ovoid; length 173.4; width 145.6; total length 232.9. Length of protomerite/total length index 25.7. Length of deutomerite/total length index 74.3. Length of protomerite/length of deutomerite index 35.4. Width of protomerite/width of deutomerite index 63.5. Satellite: protomerite hemispherical; length 40.2; width 81.6; deutomerite ovoid; length 177.4; width 113.9; total length 217.6. Length of protomerite/total length index 19.0. Length of deutomerite/total length index 81.0. Length of protomerite/length of deutomerite index 23.8. Width of protomerite/width of deutomerite index 76.7. Gametocysts spherical, diameter 225, producing multiple oocyst chains under dry storage in 36–52 h. Oocysts very uniform in shape and size, dorsum doliform with angles squared by enclosing sheath, length 8.8, width 5.5; flattened dorsoventrad with mesad tumidus, pleuron height 2.2. Morphological measurements, indices, and oocyst descriptions are given for G. cuneata, G. polymorpha and G. steini.
Small GTP‐binding Proteins Associated with Secretory Vesicles of Paramecium
Authors: PETERSON JOAN BAIER
Published: May 2007

GTP‐binding proteins act as molecular switches in a variety of membrane‐associated processes, including secretion. One group of GTP‐binding proteins, 20–30 kDa, is related to the product of the ras proto‐oncogene. In Saccharomyces cerevisiae, ras‐like GTP‐binding proteins regulate vesicular traffic in secretion. The ciliate protist Paramecium tetraurelia contains secretory vesicles (trichocysts) whose protein contents are released by regulated exocytosis. Using [α‐32P]GTP and an on‐blot assay for GTP‐binding, we detected at least seven GTP‐binding proteins of low molecular mass (22–31 kDa) in extracts of Paramecium tetraurelia. Subcellular fractions contained characteristic subsets of these seven; cilia were enriched for the smallest (22 kDa). The pattern of GTP‐binding proteins was altered in two mutants defective in the formation or discharge of trichocysts. Trichocysts isolated with their surrounding membranes intact contained two minor GTP‐binding proteins (23.5 and 29 kDa) and one major GTP‐binding protein (23 kDa) that were absent from demembranated trichocysts. This differential localization of GTP‐binding proteins suggests functional specialization of specific GTP‐binding proteins in ciliary motility and exocytosis.
Fine Structure of a New Human Microsporidian, Encephalitozoon hellem, in Culture
Authors: DIDIER PETER J. , DIDIER ELIZABETH S. , ORENSTEIN JAN M. , SHADDUCK JOHN A.
Published: May 2007

Encephalitozoon hellem is a new human microsporidian isolated from corneal biopsies and conjunctival scrapings of three AIDS patients and cultured in Madin Darby canine kidney (MDCK) cells. Encephalitozoon hellem and Encephalitozoon cuniculi display different protein profiles with sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and unique antibody binding patterns with murine antisera against Western blots of each organism. Developmental stages of E. hellem in culture are similar to E. cuniculi. Meronts are 1.3–2.7 μm in diameter, develop within a parasitophorous vacuole adjacent to the vacuolar membrane, divide by binary fission, and contain one or two discrete nuclei. Sporonts measure 2 × 3 μm, separate from the vacuolar membrane, and have a thickened outer membrane. Sporoblasts display a tri‐layered wall and possess the earliest recognized polar filaments. Mature spores measure 1 × 1.5 μm and are more electron‐dense than other stages. Each spore contains a single nucleus, a polar tubule with four to nine coils, thin electron‐dense exospore and thick, electron‐lucent endospore. Although E. hellem and E. cuniculi differ biochemically and immunologically, their fine structure and development are indistinguishable.
Axenic Cultivation of the Anaerobic Free‐Living Ciliate Trimyema compressum
Authors: BROERS CEES A.M. , STUMM CLAUDIUS K. , VOGELS GODFRIED D.
Published: May 2007

The strain N of Trimyema compressum, an anaerobic free‐living ciliate, was cultivated axenically in a medium containing a buffered salt solution, yeast extract, trypticase, and glutathione. Dead bacteria were indispensable as food; a culture of the ciliate together with heat‐killed Klebsiella pneumoniae has been established for more than one year. In the medium described, the ciliates grow to a higher cell density than in cultures with living bacteria as food. During the process of axenization, a nonmethanogenic bacterial endosymbiont was lost. In the microbodies of T. compressum, hydrogenase could be localized by the technique of indirect immunofluorescence.
The Effect of the Lipogenic Inhibitor Cerulenin, on Macrostomal Cell Formation in Tetrahymena vorax
Authors: BUHSE HOWARD E. , NABAZAS SANDRA , BUHRFEIND CATHERINE , RYALS PHIUIP E.
Published: May 2007

ABSTRACT. Macrostomal cell formation is blocked by the antibiotic cerulenin at levels of 15 μg/ml or higher. Inhibition can be reversed up to 4 h following cerulenin addition by washing and resuspending cells in new, noncerulenin‐treated transforming principle. In these latter cases, additional time equal to the time spent in the inhibitor, is needed for cells to reach control values of transformation. Neither the addition of saturated or unsaturated fatty acids, cholesterol added alone or in combination with stearic acid, nor a mixture of lipids extracted from Tetrahymena vorax reversed the cerulenin effect. Radioisotope incorporation data showed while protein synthesis was reduced by the end of 1 h and tetrahymanol synthesis by the end of 2 h, little or no effect of this inhibitor occurred on RNA or fatty acid synthesis during these times. One interpretation of these results is that cerulenin, by preventing first protein synthesis and later tetrahymanol synthesis, interferes with synthesis and formation of membranes required for the microstome to macrostome transition.
The Nuclear Apparatus of the Ditransversal Ciliate Homalozoon vermiculare (Ciliophora, Rhabdophora) during Interphase and Division. I. The Macronucleus1
Authors: DETLEF D. LEIPE , HAUSMANN KLAUS
Published: May 2007

ABSTRACT. The nuclear apparatus of Homalozoon vermiculare consists of a single moniliform macronucleus and about 25 micronuclei. The number of macronuclear segments depends (i) on the number of divisions of individual segments during the interphase and (ii) on the number of segments that arise prior to cytokinesis from the (temporary) filiform macronucleus. Precytokinetic changes of the macronucleus involve the fusion of individual segments followed by contraction and subsequent elongation of the entire macronucleus. The chromatin bodies uncoil into fine fibrils during macronuclear contraction. At the time when the division furrow appears, the macronucleus starts to renodulate. The interphase segment contains a more or less reticulated chromatin body partly attached to the nuclear envelope and about 30 polymorphous nucleoli. The latter consist of the pars granulosa, the pars fibrosa, and an additional fibrillar component. The nucleoli undergo drastic changes prior to division and the granular component disappears completely during macronuclear condensation. On the average, the macronucleus contains a 3,400‐fold amount of DNA compared with a haploid micronucleus, but the intraspecific differences in the DNA content of the entire macronucleus are extremely large. In contrast, DNA content and size of an individual segment of the macronucleus are precisely regulated during interphase.
Genetic Variants of Plateins (Alveolar Plate Proteins) Among and Within Species of Euplotes1
Authors: KLOETZEL JOHN A. , HILL BRUCE F. , KOSAKA TOSHIKAZU
Published: May 2007

ABSTRACT. In the ciliate Euplotes, each of the sub‐plasmalemmal membranous sacs (the cortical alveoli) encloses a thin polygonal scale or alveolar plate (AP). Adjoining alveoli and their contained plates are tightly integrated into a confluent monolayer that appears to strengthen and help define the shape of the cell cortex. Recently the major proteins making up the AP have been identified. Monoclonal antibodies (MAb) prepared against the AP proteins (termed plateins) of E. aediculatus show reactivity by immunofluorescence with the plates of a wide variety of Euplotes species (including E. eurystomus, E. harpa, E. woodruffi, and E. patella). However, each species tested shows a different pattern of platein bands on immunoblots, in terms of the number and apparent molecular weights (Mr) of the reactive polypeptides. One species (E. gracilis) did not show reactivity with these MAb. Intraspecific platein variants were found within the E. woodruffi complex and among strains of different geographic origin in E. aediculatus. To study the heritability of these platein variants, we used two E. aediculatus clones of different mating type, collected at the same site, that show reproducible differences in the electrophoretic mobility of their lowest Mr platein. Both share common platein bands at 125 kDa and 99 kDa. One clone has its third platein band at 97 kDa, the other clone at 95 kDa. Fourteen F1 clones from matings of these two parental strains have been tested by immunoblotting (using anti‐platein MAb). Each F1 clone has the lower Mr plateins of both parents, and hence displays (in addition to the 125‐kDa band) a triplet of bands (99, 97 and 95 kDa) in this region of the gel/blot, rather than one of the alternative doublets exhibited by either parent clone. The simplest interpretation of these results is that the two lowest Mr plateins represent Mendelian allelic variants, co‐dominant at this level of analysis. No phenotypic differences in cortical structure or properties have yet been noted that might correlate with the identified platein variants.