| method for the simultaneous establishment of many axenic cultures of paramecium. | a method is described for the simultaneous treatment of 42 (or more) stocks of paramecium, and their adaptation to growth in axenic culture. samples of dense cultures of these ciliates growing with enterobacter aerogenes are rendered bacteria-free by migration through 2 sets of tubes containing adaptation medium (peters' salts solution, stigmaterol, vitamins, and autoclaved e. aerogenes). the 2nd set of tubes contains adaptation medium plus antibiotics. bacteria-free samples containing approxima ... | 1978 | 660565 |
| atrial natriuretic factor-like peptide and its prohormone within single cell organisms. | the present investigation was designed to determine if the atrial natriuretic peptide hormonal system is present within single cell organisms. paramecium multimicronucleatum were examined with 3 sensitive and specific radioimmunoassays which recognize the n-terminus [amino acids 1-98; proanf(1-98)], the midportion of the n-terminus [amino acids 31-67; proanf(31-67)] and c-terminus (amino acids 99-126; anf) of the 126 amino acid atrial natriuretic factor (anf) prohormone. proanf(1-98), proanf(31- ... | 1992 | 1535708 |
| characterization of monoclonal antibodies to trichocyst antigens in paramecium. | ten mouse monoclonal antibodies (mabs) were raised against trichocyst contaminants present in crude or enriched lysosome fractions of paramecium multimicronucleatum. using an indirect immunofluorescence assay (ifa) and immunogold labelling on frozen thin sections, epitopes were located on the outer edge, cortex and the core of the trichocyst body, as well as the sheath covering the tip. except for the two on the tip, epitopes were reactive after sds-page under non-reducing conditions. four mabs ... | 1988 | 2477384 |
| secretory activity of the oral apparatus of ciliates: trails of adherent particles left by paramecium multimicronucleatum and tetrahymena pyriformis. | | 1965 | 5221052 |
| 22s axonemal dynein is preassembled and functional prior to being transported to and attached on the axonemes. | in an earlier study we reported the isolation of a cytoplasmic dynein from the cytosol of paramecium multimicronucleatum. in this study we report the isolation and characterization of two cytosolic axonemal dyneins (22s and 12s) as well as a 19s cytoplasmic dynein from the cytosol of whole or deciliated cells using preformed bovine brain microtubules. these three dynein species were characterized according to mass, morphology, vanadate photocleavage patterns, ctpase/atpase ratios, km and vmax va ... | 1994 | 7895285 |
| centrin is a conserved protein that forms diverse associations with centrioles and mtocs in naegleria and other organisms. | centrin, a approximately or equal to 20 kda calcium-binding protein also known as caltractin, is a component of centrosome-associated algal flagellar roots capable of calcium-mediated contraction, and is also found in the centrosomes of vertebrate cells. our analysis of a centrin gene from a protist, the amoeboflagellate naegleria gruberi, reveals conserved features that distinguish centrins from calmodulin. antibodies to bacterially expressed naegleria centrin, which also recognize yeast cdc31p ... | 1996 | 8801035 |
| cloning and sequencing of a protein involved in phagosomal membrane fusion in paramecium. | an mab was raised to the c5 phagosomal antigen in paramecium multimicronucleatum. to determine its function, the cdna and genomic dna encoding c5 were cloned. this antigen consisted of 315 amino acid residues with a predicted molecular weight of 36,594, a value similar to that determined by sds-page. sequence comparisons uncovered a low but significant homology with a schizosaccharomyces pombe protein and the c-terminal half of the beta-fructofuranosidase protein of zymomonas mobilis. lacking an ... | 1999 | 10198055 |
| phylogenetic relationships of the subclass peniculia (oligohymenophorea, ciliophora) inferred from small subunit rrna gene sequences. | peniculine ciliates have been recognized as a distinct higher taxon of ciliates for almost 50 years. however, phylogenetic relationships within the subclass peniculia are still unsettled. to contribute to our understanding of their phylogeny and provide evidence for the position of urocentrum turbo, we sequenced its small subunit (ss) rrna gene and the ssrrna genes from lembadion bullinum, frontonia sp., paramecium caudatum, paramecium multimicronucleatum, paramecium putrinum, and paramecium woo ... | 2000 | 11140457 |
| mitochondria of protozoa. | a study of thin sections of paramecium multimicronucleatum, tetrahymena pyriformis, tokophrya infusionum, and amoeba proteus shows that the mitochondria in all these protozoa are similar in certain aspects of their fine structure to that described in metazoan cells. as in higher organisms the mitochondrion is surrounded by a double limiting membrane and contains protrusions directed inward from the innermost of the double membranes. there are, however, some differences. in a majority of higher o ... | 1956 | 13357562 |
| intraspecific genetic variation in paramecium revealed by mitochondrial cytochrome c oxidase i sequences. | studies of intraspecific genetic diversity of ciliates, such as population genetics and biogeography, are particularly hampered by the lack of suitable dna markers. for example, sequences of the non-coding ribosomal internal transcribed spacer (its) regions are often too conserved for intraspecific analyses. we have therefore identified primers for the mitochondrial cytochrome c oxidase i (coi) gene and applied them for intraspecific investigations in paramecium caudatum and paramecium multimicr ... | 2006 | 16441579 |
| calmodulin localization and its effects on endocytic and phagocytic membrane trafficking in paramecium multimicronucleatum. | in ciliates, calmodulin (cam), as in other cells, has multiple functions, such as activation of regulatory enzymes and modulating calcium-dependent cellular processes. by immunogold localization, cam is concentrated at multiple sites in paramecium. it is seen scattered over the cytosol, but bound to its matrix, and is concentrated at the pores of the contractile vacuole complexes and with at least three microtubular arrays. it was localized peripheral to the nine-doublet microtubules of the cili ... | 2008 | 19120793 |
| negative geotactic behavior of paramecium caudatum is completely described by the mechanism of buoyancy-oriented upward swimming. | this paper presents evidence that the negative geotactic behavior of paramecium caudatum takes place by the mechanism of buoyancy-oriented upward swimming. photographs of swimming pathways of the organisms were completely described by two dynamic equations for the translational motion of the center of gravity of the organism's body and for the rotational motion of the organism's body about its center of gravity, where the rotational torque is induced by a slight difference in position between th ... | 1985 | 19431589 |
| endosomal system of paramecium: coated pits to early endosomes. | a detailed morphological and tracer study of endocytosis via coated pits in paramecium multimicronucleatum was undertaken to compare endocytic processes in a free-living protozoon with similar processes in higher organisms. permanent pits at the cell surface enlarge, become coated and give rise to coated vesicles (188 +/- 41 nm in diameter) that enclose fluid-phase markers such as horseradish peroxidase (hrp). both the pits and vesicles are labeled by the immunogold technique when a monoclonal a ... | 1992 | 1629255 |
| saltatory ontogeny of fishes and sensitive early life stages for ecotoxicology tests. | fish display a wide range of developmental ontogenies. these distinctions have taxonomic, evolutionary, and ecological importance in addition to practical implications on the use of fish in aquatic toxicity tests. with respect to animal welfare, vertebrates are afforded protected or non-protected status in the european union based upon whether they feed endogenously off the yolk or exogenously by procurement and ingestion of food. the concept of saltatory ontogeny suggests development is not gra ... | 2010 | 20042243 |
| variability in secondary structure of 18s ribosomal rna as topological marker for identification of paramecium species. | besides cytological and molecular applications, paramecium is being used in water quality assessment and for determination of saprobic levels. an unambiguous identification of these unicellular eukaryotes is not only essential, but its ecological diversity must also be explored in the local environment. 18srrna genes of all the strains of paramecium species isolated from waste water were amplified, cloned and sequenced. phylogenetic comparison of the nucleotide sequences of these strains with 23 ... | 2014 | 25043709 |
| signalling in ciliates: long- and short-range signals and molecular determinants for cellular dynamics. | in ciliates, unicellular representatives of the bikont branch of evolution, inter- and intracellular signalling pathways have been analysed mainly in paramecium tetraurelia, paramecium multimicronucleatum and tetrahymena thermophila and in part also in euplotes raikovi. electrophysiology of ciliary activity in paramecium spp. is a most successful example. established signalling mechanisms include plasmalemmal ion channels, recently established intracellular ca2+ -release channels, as well as sig ... | 2017 | 26487631 |
| relationships of new sibling species of paramecium jenningsi based on sequences of the histone h4 gene fragment. | paramecium jenningsi diller & earl, 1958 belongs to the "aurelia" subgroup of the genus, together with paramecium caudatum, paramecium multimicronucleatum, paramecium schewiakoffi and species of the paramecium aurelia complex. the original assumption that the morphospecies p. jenningsi was a single genetic species was questioned because a comparison of genome analyses suggested the possibility that this morphospecies contained two sibling species. to refine understanding of relationships between ... | 2007 | 17481867 |
| comparison of the evolutionary distances among syngens and sibling species of paramecium. | the morphospecies of the genus paramecium have several mating type groups, so-called syngens, composed of cells of complementary mating types. the paramecium aurelia complex is composed of 15 sibling species assigned to the species from the syngen. to increase our understanding of the evolutionary relationships among syngen and sibling species of the genus paramecium, we investigated the gene sequences of cytosol-type hsp70 from 7 syngens of paramecium caudatum and 15 sibling species of p. aurel ... | 2006 | 16293424 |
| esterase variations between the 14 syngens of paramecium aurelia under axenic growth. | under axenic growth all 14 syngens of paramecium aurelia have 4 types of esterases. the three major types (a, b and cathodal c) vary independently in electrophoretic mobility among the syngens. using these three esterases, stocks can be keyed to a syngen, except for the groupings 1-3-5 and 7-13. using 5 other enzymes only syngens 1 and 5 cannot be distinguished. most syngens differ from each other in 6 out of the 8 enzymes. an axenically-grown stock of paramecium multimicronucleatum collected in ... | 1973 | 17248596 |
| "candidatus gortzia shahrazadis", a novel endosymbiont of paramecium multimicronucleatum and a revision of the biogeographical distribution of holospora-like bacteria. | holospora spp. and "candidatus gortzia infectiva", known as holospora-like bacteria (hlb), are commonly found as nuclear endosymbionts of ciliates, especially the paramecium genus. hlb are related by phylogenetic relationships, morphological features, and life-cycles, which involve two alternating morphotypes: reproductive and infectious forms (rf, if). in this paper we describe a novel species belonging to the "ca. gortzia" genus, detected in p. multimicronucleatum, a ciliate for which infectio ... | 2016 | 27867371 |
| multiple lines of evidence shed light on the occurrence of paramecium (ciliophora, oligohymenophorea) in bromeliad tank water. | phytotelmata are vegetal structures that hold water from the rain, and organic matter from the forest and the soil, resulting in small, compartmentalized bodies of water, which provide an essential environment for the establishment and development of many organisms. these microenvironments generally harbor endemic species, but many organisms that are found in lakes and rivers, are also present. here, we report, for the first time, the occurrence of the ciliate genus paramecium in the tank of the ... | 2014 | 24011017 |
| surface interactions affect the toxicity of engineered metal oxide nanoparticles toward paramecium. | to better understand the potential impacts of engineered metal oxide nanoparticles (nps) in the ecosystem, we investigated the acute toxicity of seven different types of engineered metal oxide nps against paramecium multimicronucleatum, a ciliated protozoan, using the 48 h lc(50) (lethal concentration, 50%) test. our results showed that the 48 h lc(50) values of these nps to paramecium ranged from 0.81 (fe(2)o(3) nps) to 9269 mg/l (al(2)o(3) nps); their toxicity to paramecium increased as follow ... | 2012 | 22693953 |
| variation in ribosomal and mitochondrial dna sequences demonstrates the existence of intraspecific groups in paramecium multimicronucleatum (ciliophora, oligohymenophorea). | this is the first phylogenetic study of the intraspecific variability within paramecium multimicronucleatum with the application of two-loci analysis (its1-5.8s-its2-5'lsu rdna and coi mtdna) carried out on numerous strains originated from different continents. the species has been shown to have a complex structure of several sibling species within taxonomic species. our analysis revealed the existence of 10 haplotypes for the rdna fragment and 15 haplotypes for the coi fragment in the studied m ... | 2012 | 22342870 |
| mathematical modelling of ciliary movement mechanism. | the main purpose of the paper was to present a new approach to the mathematical modelling of ciliary movements. this approach is based on the solution of the inverse problem of the dynamics, which is described by lagrange's equations for the system of successively hinged rigid rods. in this case, as is well known, the generalized forces may be found as the time functions. it is proposed to represent these functions by the functions of generalized coordinates and velocities and also of the model ... | 2011 | 22097909 |
| the native structure of cytoplasmic dynein at work translocating vesicles in paramecium. | in paramecium multimicronucleatum, the discoidal vesicles, the acidosomes and the 100-nm carrier vesicles are involved in phagosome formation, phagosome acidification and endosomal processing, respectively. numerous cross bridges link these vesicles to the kinetic side of the microtubules of a cytopharyngeal microtubular ribbon. vesicles are translocated along these ribbons in a minus-end direction towards the cytopharynx. a monoclonal antibody specific for the light vanadate-photocleaved fragme ... | 2011 | 20837374 |
| thermo-sensitive response based on the membrane fluidity adaptation in paramecium multimicronucleatum. | relationships between the thermo-sensitive response and membrane lipid fluidity were studied using a ciliated protozoan, paramecium multimicronucleatum. paramecium elicits a transient membrane depolarization in response to a cooling stimulus (temperature drop). the depolarization amplitude was largest when the cooling stimulus was started from the culture temperature, whilst when cooling started at a temperature more than 5 degrees c higher or lower than the culture temperature, only a small dep ... | 2009 | 19684209 |
| electrical properties and fusion dynamics of in vitro membrane vesicles derived from separate parts of the contractile vacuole complex of paramecium multimicronucleatum. | the contractile vacuole complex of paramecium multimicronucleatum transforms into membrane-bound vesicles on excision from the cell. the i-v relationship was linear in a voltage range of -80 to +80 mv in all vesicles, despite being derived from different parts of the contractile vacuole complex. no voltage-gated unit currents were observed in membrane patches from the vesicles. vesicles derived from the radial arm showed a membrane potential of >10 mv, positive with reference to the cytosol, whi ... | 2005 | 16215222 |
| cell volume control in paramecium: factors that activate the control mechanisms. | a fresh water protozoan paramecium multimicronucleatum adapted to a given solution was found to swell until the osmotic pressure difference between the cytosol and the solution balanced the cytosolic pressure. the cytosolic pressure was generated as the cell swelled osmotically. when either one or both of these pressures was somehow modified, cell volume would change until a new balance between these pressures was established. a hypothetical osmolyte transport mechanism(s) was presumably activat ... | 2005 | 15671341 |
| hypo-osmotic or ca2+-rich external conditions trigger extra contractile vacuole complex generation in paramecium multimicronucleatum. | the freshwater ciliated protozoan, paramecium multimicronucleatum, usually possesses two contractile vacuole complexes (cvcs). the number of cvcs in a single cell, however, may vary from 1 to 7. we found that the number of cells that have more than two cvcs increased after the cells were exposed to a hypo-osmotic or a high ca2+ condition. it is assumed that the biological significance of this increase in the number of cvcs is to enhance the cell's ability to eliminate excess water or ca2+ from t ... | 2003 | 14610031 |
| the ionic composition of the contractile vacuole fluid of paramecium mirrors ion transport across the plasma membrane. | in vivo k+, na+, ca2+, cl- and h+ activities in the cytosol and the contractile vacuole fluid, the overall cytosolic osmolarity, the fluid segregation rate per contractile vacuole and the membrane potential of the contractile vacuole complex of paramecium multimicronucleatum were determined in cells adapted to 24 or 124 mosm l(-1) solutions containing as the monovalent cation(s): 1) 2 mmol l(-1) k+; 2) 2 mmol l(-1) na+; 3) 1 mmol l(-1) k+ plus 1 mmol l(-1) na+; or 4) 2 mmol l(-1) choline. in cel ... | 2002 | 12416727 |
| relationship between the membrane potential of the contractile vacuole complex and its osmoregulatory activity in paramecium multimicronucleatum. | the electric potential of the contractile vacuole (cv) of paramecium multimicronucleatum was measured in situ using microelectrodes, one placed in the cv and the other (reference electrode) in the cytosol of a living cell. the cv potential in a mechanically compressed cell increased in a stepwise manner to a maximal value (approximately 80 mv) early in the fluid-filling phase. this stepwise change was caused by the consecutive reattachment to the cv of the radial arms, where the electrogenic sit ... | 2002 | 12235204 |
| the vacuolar-atpase of paramecium multimicronucleatum: gene structure of the b subunit and the dynamics of the v-atpase-rich osmoregulatory membranes. | previous studies have shown that the vacuolar-atpase (v-atpase) of the contractile vacuole complexes (cvcs) in paramecium multimicronucleatum is necessary for fluid segregation and osmoregulation. in the current study, immunofluorescence showed that the development of a new cvc begins with the formation of a new pore around which the collecting canals form. the decorated membranes are then deposited around the newly formed collecting canals. quick-freeze deep-etch techniques reveal that six 10-n ... | 2006 | 12120983 |
| osmoregulation in paramecium: in situ ion gradients permit water to cascade through the cytosol to the contractile vacuole. | in vivo k(+), na(+), ca(2+) and cl(-) activities in the cytosol and the contractile vacuole fluid of paramecium multimicronucleatum were determined in cells adapted to a number of external osmolarities and ionic conditions by using ion-selective microelectrodes. it was found that: (1) under standardized saline conditions k(+) and cl(-) were the major osmolytes in both the cytosol and the contractile vacuole fluid; and (2) the osmolarity of the contractile vacuole fluid, determined from k(+) and ... | 2002 | 12006618 |
| phagosome formation in paramecium: roles of somatic and oral cilia and of solid particles as revealed by video microscopy. | the roles of somatic and oral cilia and solid particles during digestive vacuole (dv) formation in paramecium multimicronucleatum were investigated using video-enhanced and immunofluorescence microscopy. membrane incorporation into dvs was found to increase linearly with increasing particle concentration. the rate of discoidal vesicle transport to the cytopharynx was not affected by particles, showing that particles are not required for membrane trafficking to the cytopharynx. however, the prese ... | 2006 | 11831772 |
| cellular membranes that undergo cyclic changes in tension: direct measurement of force generation by an in vitro contractile vacuole of paramecium multimicronucleatum. | the contractile vacuole of the fresh water protozoan paramecium is a membrane-bound vesicle that expels excess cytosolic water, acquired osmotically, through its periodic exocytotic activity. the in vitro contractile vacuole, isolated in a small amount of cytosol from the paramecium cell and confined under mineral oil, showed periodic rounding and slackening at regular intervals for an extended time. the contractile vacuole rounded against the cytosol-mineral oil boundary tension. the tension at ... | 2001 | 11171384 |
| how external osmolarity affects the activity of the contractile vacuole complex, the cytosolic osmolarity and the water permeability of the plasma membrane in paramecium multimicronucleatum. | the rate of fluid expulsion, r(cvc), from the contractile vacuole complex (cvc) of paramecium multimicronucleatum was estimated from the volume of the contractile vacuoles (cvs) immediately before the start of fluid discharge and from the time elapsing between discharges. the r(cvc) increased when the cell was exposed to a strongly hypotonic solution and decreased in a weakly hypotonic solution. when the cell was exposed to an isotonic or a hypertonic solution, r(cvc) fell to zero. the time cons ... | 2001 | 11136615 |
| effect of a 60 hz magnetic field on the behavior of paramecium. | paramecium multimicronucleatum was used as a model cell to study the effects of 60 hz magnetic fields on swimming behavior. when exposed to a vertical field of 0.6 t, the cells accumulated at the upper end of the cuvette. an analysis of the swimming behavior revealed that the exposure to the field increased the number of cells swimming upwards maximally at 1 min after onset of the exposure. this effect of the magnetic field was transient, disappearing within a few minutes during the exposure. it ... | 2000 | 11102948 |
| prostaglandin i(2), a possible thermo-sensory mediator in paramecium. | thermo-sensory mechanisms are little understood. the protozoan, paramecium multimicronucleatum, is sensitive and responsive to a cooling stimulus. we found that inhibitors of prostaglandin (pg) biosynthesis reduced the response to the cooling stimulus. inversely, the response suppressed by the inhibitors was recovered by application of stable pgi(2) analogs, including iloprost. paramecium cells showed binding activity specific for [(3)h]iloprost. moreover, an arachidonic acid metabolite, possibl ... | 2000 | 10873637 |
| periodic tension development in the membrane of the in vitro contractile vacuole of paramecium multimicronucleatum: modification by bisection, fusion and suction. | the contractile vacuole of the freshwater protozoan paramecium multimicronucleatum is a membrane-bound exocytotic vesicle that expels excess cytosolic water. the in vitro contractile vacuole isolated from p. multimicronucleatum along with a small amount of cytosol and confined under mineral oil showed periodic rounding and slackening at fairly regular intervals. activity lasted for over 30 min at room temperature (24-27 degrees c). the rounding of the in vitro contractile vacuole corresponded to ... | 2000 | 10607534 |
| a key function of non-planar membranes and their associated microtubular ribbons in contractile vacuole membrane dynamics is revealed by electrophysiologically controlled fixation of paramecium. | the contractile vacuole complex of the fresh water protozoan paramecium multimicronucleatum exhibits periodic exocytotic activity. this keeps cytosolic osmolarity at a constant value. the contractile vacuole, the central exocytotic vesicle of the complex, becomes disconnected from its surrounding radial arms and rounds before its fluid content is expelled. we previously proposed a hypothesis that the rounding of the contractile vacuole corresponds to an increase in its membrane tension and that ... | 1999 | 10523509 |
| simple fluctuation of ca2+ elicits the complex circadian dynamics of cyclic amp and cyclic gmp in paramecium. | the circadian dynamics of cyclic adenosine 3',5'-monophosphate (camp) and cyclic guanosine 3',5'-monophosphate (cgmp) were simulated in paramecium multimicronucleatum. the mathematical functions determined closely mimic the ca2+ dependence of adenylate cyclase (ac) and guanylate cyclase (gc) activities as documented in p. tetraurelia. patterns of camp concentration ([camp]), cgmp concentration ([cgmp ]), and the ratio [cgmp]/[camp] were calculated with respect to ca2+ concentrations ([ca2+]) flu ... | 1999 | 9858473 |
| cyclic changes in the tension of the contractile vacuole complex membrane control its exocytotic cycle | the freshwater protozoan paramecium multimicronucleatum maintains a constant cytosolic osmolarity through the exocytotic activity of its contractile vacuole complex. the contractile vacuole (cv) expels the excess cytosolic water, acquired osmotically, to the exterior of the cell at fairly regular intervals. in a single exocytotic cycle, the cv swells as the cytosolic water enters the vacuole, rounds up, and then rapidly shrinks as the fluid is expelled through the pore of the cv. the exocytotic ... | 1998 | 9716516 |
| the contractile vacuole fluid discharge rate is determined by the vacuole size immediately before the start of discharge in paramecium multimicronucleatum | the precise relationship between the rate of contractile vacuole fluid discharge and the vacuole diameter at the start of systole was determined in cells of paramecium multimicronucleatum subjected to various external conditions. the rate of discharge was higher when the diameter was larger. when the rate of discharge was plotted against the diameter, the points fell around a single parabolic line passing through the origin and were independent of the external conditions employed. this implies t ... | 1997 | 9319645 |
| possible mediation of g-proteins in cold-sensory transduction in | the possible involvement of g-proteins in cold-sensory transduction was examined using voltage-clamped paramecium multimicronucleatum into which non-hydrolyzable guanosine nucleotide analogues had been applied intracellularly. guanosine-5'-o-3-thiotriphosphate, guanosine-5'-o-2-thiodiphosphate and aluminium fluoride all reduced the transient inward current in response to cooling, suggesting the possibility that g-proteins mediate cold-sensory transduction. internal application of a ca2+ chelator ... | 1997 | 9318830 |
| how does the contractile vacuole of paramecium multimicronucleatum expel fluid? modelling the expulsion mechanism | to examine the forces needed for discharge of the fluid contents from the contractile vacuole of paramecium multimicronucleatum, the time course of the decrease in vacuole diameter during systole (the fluid-discharging period) was compared with that of various vacuole discharge models. the observed time course did not fit that predicted by a model in which contraction of an actin­myosin network surrounding the vacuole caused discharge nor that predicted by a model in which the surface tensio ... | 1997 | 9318470 |
| high resolution view of the true cytosolic membrane surface of phagosomes of known ages purified from paramecium. | techniques were used for viewing the true cytosolic surfaces of the membranes of intracellular organelles by field emission scanning electron microscopy (sem). cells of paramecium multimicronucleatum were fed briefly with magnetic beads followed by a chase which advanced the newly formed digestive vacuoles (dvs) to predetermined ages. these bead-containing phagosomes were isolated from the whole cell homogenates with a magnet and were determined to be intact by fluorescence microscopy. antigenic ... | 1996 | 8929564 |
| hyperosmotic stress leads to reversible dissociation of the proton pump-bearing tubules from the contractile vacuole complex in paramecium. | to study the effect of hyperosmotic stress on the structure and function of the contractile vacuole complex of paramecium multimicronucleatum, we employed two different monoclonal antibody markers: one to a decorated spongiome antigen (a4) and a second to an antigen found on all other membranes of the contractile vacuole complex (g4). a hyperosmotic condition was produced by adding sorbitol to the axenic culture medium which induced both dose- and time-dependent decreases in the vacuole's expuls ... | 1996 | 8834807 |
| rapid bulk replacement of acceptor membrane by donor membrane during phagosome to phagoacidosome transformation in paramecium. | the extent to which a donor membrane will be retrieved, or if it is retrieved at all after it fuses with an acceptor membrane, is usually difficult to determine. we have studied the dynamics of membrane retrieval in the phagosome system of paramecium multimicronucleatum using six monoclonal antibody markers. our previous freeze-fracture and transmission electron microscopic studies have indicated that extensive changes take place in the membrane of the young phagosome as it progresses through it ... | 1995 | 7622609 |
| reconstitution of metachronal waves in ciliated cortical sheets of paramecium - asymmetry of the ciliary movements | in conditions in which ciliated cortical sheets prepared from detergent-extracted paramecium multimicronucleatum cells adhered to glass coverslips on a microscope stage, perfusion of a reactivation medium containing atp plus cyclic amp or cyclic gmp generated metachronal waves. an analysis of the ciliary movements that generate these metachronal waves yielded the following results. during the generation of metachronal waves, there were phase differences in the ciliary orientation of adjacent cil ... | 1994 | 9317363 |
| reconstitution of metachronal waves in ciliated cortical sheets of paramecium - wave stabilities | we reconstituted metachronal waves on ciliated cortical sheets prepared from detergent-extracted paramecium multimicronucleatum cells. ciliary movements of the cortical sheet, whose intracellular side adhered to a glass coverslip, were reactivated by perfusion of a basic reactivation medium containing atp. in this condition, the ciliary field showed only unstable localised ripples. addition of either cyclic amp or cyclic gmp to the basic reactivation medium generated propagating metachronal wave ... | 1994 | 9317340 |
| osmoregulation in paramecium: the locus of fluid segregation in the contractile vacuole complex. | in a previous study, monoclonal antibody ds-1 was found to specifically label the decorated spongiome along the radial arms of the contractile vacuole complexes in paramecium multimicronucleatum. fluorescein isothiocyanate-conjugated ds-1, when injected into cells, labels the radial arms initially, but with increasing postinjection time both the intensity of fluorescence and the number of fluorescently labeled radial arms were reduced. when these cells were fixed after 45 minutes and probed indi ... | 1993 | 8282774 |
| monoclonal antibody study of the decorated spongiome of contractile vacuole complexes of paramecium. | a monoclonal antibody (mab) has been developed and selected by immunofluorescence for the radial canals of the contractile vacuole complex (cvc) of paramecium multimicronucleatum. by applying indirect immunogold labeling to thin frozen sections this mab has been shown at the electron microscopic level to be specific for the decorated spongiome. we have used the mab to study the normal interfission appearance as well as developmental stages of the decorated spongiomes. two decorated spongiomes, p ... | 1990 | 2229197 |
| intracellular binding of wheat germ agglutinin by golgi complexes, phagosomes, and lysosomes of paramecium multimicronucleatum. | the compartments of the paramecium digestive system were investigated with wheat germ agglutinin (wga). by use of cryosectioning or lowicryl k4m embedding combined with pulse-chase studies and wga-gold labeling, wga binding sites were located on membranes of the phagosome-lysosome system, including all four stages of digestive vacuoles, the discoidal vesicles, acidosomes, and lysosomes. in addition, the contents of lysosomes, cisternae at the trans face of golgi stacks, and coated and uncoated b ... | 1989 | 2911005 |
| the paramecium circadian behavioral rhythm: light phase response curves and entrainment. | the population of a ciliate protozoan, paramecium multimicronucleatum, exhibits a circadian rhythm as measured by the number of the cells traversing an observation point ("traverse frequency," or tf). the present study examined phase shifting of the tf rhythm by administering 2-hr light pulses at different phases of the circadian cycle to cultures free-running in constant darkness (dd). the results were summarized in a phase response curve (prc), categorized as type 1. this prc indicated a relat ... | 1987 | 2979666 |
| evaluation of carbamate toxicity: acute toxicity in a culture of paramecium multimicronucleatum upon exposure to aldicarb, carbaryl, and mexacarbate as measured by warburg respirometry and acute plate assay. | the present study was undertaken to explore the acute toxicity of three carbamate pesticides, aldicarb, carbaryl, and mexacarbate, on a population of paramecium multimicronucleatum. the toxicity was evaluated by the warburg respirometer and the static acute plate assay. aldicarb, carbaryl, and mexacarbate were shown to significantly inhibit cumulative oxygen uptake at 24 hr in the paramecium culture at 160, 120, and 100 ppm, respectively. aldicarb, carbaryl, and mexacarbate concentrations of 60, ... | 1985 | 3920045 |
| attachment of paramecium to polystyrene surfaces. ii. induction of the attachment by hydrophobic reagents or immune immunoglobulin g. | mating-reactive cells of paramecium multimicronucleatum attach to a polystyrene surface (falcon 10070 culture dishes) irrespective of extracellular ion concentration and swimming velocity. this attachment is induced in cells that are not mating-reactive by treatment with purified immunoglobulin g from antiserum, which blocks cells from mating or from antiserum prepared against the surface-localized immobilization antigens. treatment with certain hydrophobic reagents such as phenethylamine, benzy ... | 1983 | 6619204 |
| the effects of phentolamine on the nephridial apparatus of paramecium multimicronucleatum. | | 1975 | 1145981 |
| [effect of boron on the heat resistance of paramecium multimicronucleatum, starved at different temperatures]. | | 1974 | 4450259 |
| control of mating type expression in paramecium multimicronucleatum, syngen 2. | | 1972 | 5009376 |
| electron microscopy of the nuclear events during binary fission in paramecium multimicronucleatum. | | 1972 | 5008850 |
| cell division: a second circadian clock system in paramecium multimicronucleatum. | light-dark cycles entrain a pattern of division in a population of individually isolated cells cultured in excess nutrients at 14 degrees c. this pattern persists for at least 8 days in continuous dim light. both clones which do and which do not express a circadian rhythm of mating-type reversals can be entrained. the phase is a clonal characteristic. | 1969 | 5783716 |
| the mechanism of the nephridial apparatus of paramecium multimicronucleatum. ii. the filling of the vesicle by action of the ampullae. | our recent analysis of the nephridial apparatus of paramecium multimicronucleatum by high-speed cinematography (300 fps at x 250) indicates that before the water expulsion vesicle ("contractile vacuole") is completely voided of fluid during expulsion, the ampullae surrounding and confluent with the vesicle swell with fluid entering from their respective nephridial tubules. once the membranes of the excretory pore at the base of the excretory canal (leading from the vesicle proper to the outside) ... | 1969 | 5761920 |
| the mechanism of the nephridial apparatus of paramecium multimicronucleatum. i. expulsion of water from the vesicle. | recent analysis of the mechanism of the nephridial apparatus of paramecium multimicronucleatum by high-speed cinematography (300 fps at x 250) confirms the observations by electron microscopy (schneider, 1960) that once the pore is opened, the vesicle is invaginated by adjacent cytoplasm and is emptied by collapsing under pressure from that cytoplasm, aided perhaps by pressure of the fibrils which anchor the ampullae to the excretory canal. there is no indication of active contraction of the ves ... | 1968 | 5645838 |
| adenosine triphosphate acceleration of the nephridial apparatus of paramecium multimicronucleatum. | | 1968 | 5643473 |
| a circadian rhythm of mating type reversals in paramecium multimicronucleatum, syngen 2, and its genetic control. | | 1966 | 5924093 |
| induction of conjugation by cell-free preparations in paramecium multimicronucleatum. | a cell-free preparation composed mainly of cilia, obtained by treatment with k(2)cr(2)o(7) from stocks of paramecium multimicronucleatum (syngen 2) pure for mating type, can regularly induce conjugation in intact animals of the opposite mating type. | 1964 | 14224501 |
| cellular narcosis of paramecium multimicronucleatum by xenon and other chemically inert gases. | | 1964 | 14231182 |
| effects of co2 on paramecium multimicronucleatum. | | 1964 | 14179742 |
| cytology of conjugation in paramecium multimicronucleatum, syngen 2, stock ii. | | 1964 | 14179739 |
| some electron microscopic observations on the fine structures in paramecium multimicronucleatum. | | 1964 | 14154270 |
| studies on feeding and digestion in protozoa. vi. the effect of ingestion of non-nutritive particles on acid phosphatase in paramecium multimicronucleatum. | | 1963 | 14093705 |
| studies on feeding and digestion in protozoa. v. demonstration of some phosphatases and carboxylic esterases in paramecium multimicronucleatum by histochemical methods. | | 1962 | 13936513 |
| mutation in the protozoan paramecium multimicronucleatum as a result of x-irradiation. | mutations have been produced in the protozoan paramecium multimicronucleatum by repeatedly exposing clonal cultures of the animals to large dosages of x-irradiation. the descendants of x-rayed survivors showed the following changes, which persisted in culture: destruction and loss of all micronuclei, decrease in vitality and reproductive rate, increase in x-radiation sensitivity, monstrosity, and reduced body size. | 1959 | 13624703 |
| the fine structure of cortical components of paramecium multimicronucleatum. | the electron microscope was used to study the structure and three dimensional relationships of the components of the body cortex in thin sections of paramecium multimicronucleatum. micrographs of sections show that the cortex is covered externally by two closely apposed membranes (together approximately 250 a thick) constituting the pellicle. beneath the pellicle the surface of the animal is molded into ridges that form a polygonal ridgework with depressed centers. it is these ridges that give t ... | 1955 | 13278368 |
| paramecium multimicronucleata vs. paramecium multimicronucleatum. | | 1937 | 17732934 |
| paramecium multimicronucleata vs. paramecium multimicronucleatum. | | 1936 | 17744524 |