Publications

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the ciliary protein ift57 in the macronucleus of paramecium.the intraflagellar transport ift57 protein is essential for ciliary growth and maintenance. also known as hippi, human ift57 can be translocated to the nucleus via a molecular partner of the huntingtin, hip1, inducing gene expression changes. in paramecium tetraurelia, we identified four ift57 genes forming two subfamilies ift57a/b and ift57c/d arising from whole genome duplications. the depletion of proteins of the two subfamilies induced ciliary defects and ift57a and ift57c localized in basal ...201828474836
investigation of the effect of biologically active threo-ds-isocitric acid on oxidative stress in paramecium caudatum.the effect of biologically active form (threo-ds-) of isocitric acid (ica) on oxidative stress was studied using the infusorian paramecium caudatum stressed by hydrogen peroxide and salts of some heavy metals (cu, pb, zn, and cd). ica at concentrations between 0.5 and 10 mm favorably influenced the infusorian cells with oxidative stress induced by the toxicants studied. the maximal antioxidant effect of ica was observed at its concentration 10 mm irrespective of the toxicant used (either h2o2 or ...201828976247
zebrafish (danio rerio) as a vertebrate model host to study colonization, pathogenesis, and transmission of foodborne escherichia coli o157.foodborne infections with enterohemorrhagic escherichia coli (ehec) are a major cause of diarrheal illness in humans and can lead to severe complications such as hemolytic uremic syndrome. cattle and other ruminants are the main reservoir of ehec, which enters the food chain through contaminated meat, dairy, or vegetables. here, we describe the establishment of a vertebrate model for foodborne ehec infection, using larval zebrafish (danio rerio) as a host and the protozoan prey paramecium caudat ...201728959735
paramecium caudatum as a source of nitric oxide: chemiluminescent detection based on bluestar® forensic reagent connected with microdialysis.nitric oxide (no) chemistry inside the body is the most interesting part of its behavior. no is involved in controlling blood pressure, and in transmitting nerve signals and a variety of other signaling processes. to explain the behavior of no, it is necessary to determine its immediate concentration or observe time-dependent changes in its concentration. in paramecium caudatum, no is formed by calcium-dependent nnos (nos1)-like protein, which is distributed in the cytoplasm. no synthesis affect ...201728581129
response of aquatic protists to electric field exposure.to test the effects of short-term exposure of aquatic organisms to electric field (ef) with negligible magnetic component.201728452248
particle sorting by paramecium cilia arrays.motile cilia are cell-surface organelles whose purposes, in ciliated protists and certain ciliated metazoan epithelia, include generating fluid flow, sensing and substance uptake. certain properties of cilia arrays, such as beating synchronisation and manipulation of external proximate particulate matter, are considered emergent, but remain incompletely characterised despite these phenomena having being the subject of extensive modelling. this study constitutes a laboratory experimental characte ...201728410875
evolutionary rescue and local adaptation under different rates of temperature increase: a combined analysis of changes in phenotype expression and genotype frequency in paramecium microcosms.evolutionary rescue (er) occurs when populations, which have declined due to rapid environmental change, recover through genetic adaptation. the success of this process and the evolutionary trajectory of the population strongly depend on the rate of environmental change. here we investigated how different rates of temperature increase (from 23 to 32 °c) affect population persistence and evolutionary change in experimental microcosms of the protozoan paramecium caudatum. consistent with theory on ...201728222239
atmospheric pressure maldi mass spectrometry imaging of tissues and cells at 1.4-μm lateral resolution.we report an atmospheric pressure (ap) matrix-assisted laser desorption/ionization (maldi) mass spectrometry imaging (msi) setup with a lateral resolution of 1.4 μm, a mass resolution greater than 100,000, and accuracy below ±2 p.p.m. we achieved this by coupling a focusing objective with a numerical aperture (na) of 0.9 at 337 nm and a free working distance of 18 mm in coaxial geometry to an orbitrap mass spectrometer and optimizing the matrix application. we demonstrate improvement in image co ...201727842060
effect of cypermethrin on the growth of ciliate protozoan paramecium caudatum.the objective of this study is to assess the effect of cypermethrin on the growth of ciliate protozoan paramecium caudatum.201726862268
endogenous physical regulation of population density in the freshwater protozoan paramecium caudatum.studies confirm physical long-range cell-cell communication, most evidently based on electromagnetic fields. effects concern induction or inhibition of cell growth. their natural function is unclear. with the protozoan paramecium caudatum i tested whether the signals regulate cell density and are electromagnetic. up to 300 cells/ml, cell growth in clones of this study is decreasingly pronounced. using cuvettes as chemical barriers enabling physical communication  i  placed 5 indicator cells/ml, ...201729062014
laboratory scale microbial food chain to study bioaccumulation, biomagnification, and ecotoxicity of cadmium telluride quantum dots.the increasing applications of engineered nanomaterials (enms) in consumer products warrant a careful evaluation of their trophic transfer and consequent ecological impact. in the present study, a laboratory scale aquatic microbial food chain was established using bacteria (escherichia coli (e. coli)) as a prey and ciliated protozoan (paramecium caudatum) as a predator organism to determine the impact of cadmium telluride quantum dots (cdte qds). we observed that 29% of bacterivory potential of ...201728068760
assessment of agglomeration, co-sedimentation and trophic transfer of titanium dioxide nanoparticles in a laboratory-scale predator-prey model system.nano titanium dioxide (ntio2) is the most abundantly released engineered nanomaterial (enm) in aquatic environments. therefore, it is prudent to assess its fate and its effects on lower trophic-level organisms in the aquatic food chain. a predator-and-prey-based laboratory microcosm was established using paramecium caudatum and escherichia coli to evaluate the effects of ntio2. the surface interaction of ntio2 with e. coli significantly increased after the addition of paramecium into the microco ...201627530102
performance analysis of chemotaxis controllers: which has better chemotaxis controller, escherichia coli or paramecium caudatum?chemotaxis is the biological phenomenon in which organisms move to a more favorable location in an environment with a chemical attractant or repellent. since chemotaxis is a typical example of the environmental response of organisms, it is a fundamental topic in biology and related fields. we discuss the performance of the internal controllers that generate chemotaxis. we first propose performance indices to evaluate the controllers. based on these indices, we evaluate the performance of two con ...201626336141
identification and functional characterization of an uncharacterized antimicrobial peptide from a ciliate paramecium caudatum.the global ever-growing concerns about multi-drug resistant (mdr) microbes leads to urgent demands for exploration of new antibiotics including antimicrobial peptides (amps). here we demonstrated that a cdna from ciliata paramecium caudatum, designated pcamp1, coded for a protein with features characteristic of amps, which is not homologous to any amps currently known. both the c-terminal 91 amino acid residues of pcamp1, cpcamp1, expressed in escherichia coli and the c-terminal 26 amino acid re ...201626883426
changes in the ecological properties of organic wastes during their biological treatment.organic wastes, such as the organic fractions of municipal solid waste (ofmsw) or sewage sludge (ss), have become a serious environmental problem in russia as well as in other countries. the use of these wastes as soil amendments allows their negative impact on the environment to be minimized. however, before these wastes can be used, they need to be treated appropriately in order to decrease their level of hazard. in this study, composting of raw ss, ofmsw, a mixture of these two wastes (ofmsw+ ...201627692790
protozoan predation of escherichia coli o157:h7 is unaffected by the carriage of shiga toxin-encoding bacteriophages.escherichia coli o157:h7 is a food-borne bacterium that causes hemorrhagic diarrhea and hemolytic uremic syndrome in humans. while cattle are a known source of e. coli o157:h7 exposure resulting in human infection, environmental reservoirs may also be important sources of infection for both cattle and humans. bacteriophage-encoded shiga toxins (stx) carried by e. coli o157:h7 may provide a selective advantage for survival of these bacteria in the environment, possibly through their toxic effects ...201626824472
physical non-contact communication between microscopic aquatic species: novel experimental evidences for an interspecies information exchange.previous experiments on physical non-contact communication within same species gave rise to test for this type of communication also across the species border, which was the aim of the present study. it was found that autotrophic unicellular organisms (euglena viridis), separated by cuvettes, affected the proliferation rate of heterotrophic unicellular organisms (paramecium caudatum). further, the heterotrophic unicellular organism affected also the proliferation rate of a multicellular heterotr ...201627042178
effects of diuron and carbofuran pesticides in their pure and commercial forms on paramecium caudatum: the use of protozoan in ecotoxicology.toxic effects of diuron and carbofuran on paramecium caudatum were evaluated. acute and chronic tests were conducted with diuron and carbofuran active ingredients and their commercial formulations, diuron nortox(®) 500 sc and furadan(®) 350 sc, respectively. the sensitivity range of p. caudatum to reference substance sodium chloride was established. a preliminary risk assessment of diuron and carbofuran for brazilian water bodies was performed. the tests indicated that toxicity of pure diuron an ...201626890484
ciliate paramecium is a natural reservoir of legionella pneumophila.legionella pneumophila, the causative agent of legionnaires' disease, replicates within alveolar macrophages and free-living amoebae. however, the lifestyle of l. pneumophila in the environment remains largely unknown. here we established a novel natural host model of l. pneumophila endosymbiosis using the ciliate paramecium caudatum. we also identified legionella endosymbiosis-modulating factor a (lefa), which contributes to the change in life stage from endosymbiosis to host lysis, enabling es ...201627079173
[biological effects of electromagnetic radiation of extremely high frequencies combined with physiologically active compounds].the study of the action of the electromagnetic radiation (emr) of low intensity (10 microw/cm2) in the range of frequencies 120-170 ghz at the test-reaction of infusoria paramecium caudatum was carried out. the resonant character of the effects was established. the emr action at 156.6 and 161.3 ghz caused the increase of infusorians mobility, the action at frequencies 151.8, 155.7, 167.1 ghz caused the mobility reduction. isolated and combined with emr effects of nicotine (10(-4)-10(-15) mol/l) ...201618825995
excitable membranes and action potentials in paramecia: an analysis of the electrophysiology of ciliates.the ciliate paramecium caudatum possesses an excitable cell membrane whose action potentials (aps) modulate the trajectory of the cell swimming through its freshwater environment. while many stimuli affect the membrane potential and trajectory, students can use current injection and extracellular ionic concentration changes to explore how aps cause reversal of the cell's motion. students examine these stimuli through intracellular recordings, also gaining insight into the practices of electrophy ...201526557800
dispersal, environmental forcing, and parasites combine to affect metapopulation synehrony and stability.dispersal can have positive and negative effects on metapopulation stability and persistence. one prediction is that high levels of dispersal synchronize density fluctuations between subpopulations. however, little is still known about how biotic and abiotic factors combine to modify the effects of dispersal rate on synchrony and metapopulation dynamics. in a fully factorial experimental design, we investigated the combined effects of (1) dispersal, (2) parasite infection, and (3) synchrony in t ...201526236913
long-term selection experiment produces breakdown of horizontal transmissibility in parasite with mixed transmission mode.evolutionary transitions from parasitism toward beneficial or mutualistic associations may encompass a change from horizontal transmission to (strict) vertical transmission. parasites with both vertical and horizontal transmission are amendable to study factors driving such transitions. in a long-term experiment, microcosm populations of the protozoan paramecium caudatum and its bacterial parasite holospora undulata were exposed to three growth treatments, manipulating vertical transmission oppo ...201525756600
[lotka-volterra model of competition between two species and gause experiments: is there any correspondence?].analysis of deviations between trajectories of lotka-volterra model of competition between two species and g.f. gause experimental time series on combined cultivation of paramecium aurelia and paramecium caudatum shows that with rather big probability there is no correspondence between model and experimental datasets. testing of sets of deviations was provided on symmetry with. respect to origin (kolmogorov-smirnov, lehmann-rosenblatt, wald-wolfowitz, and munn-whitney criterions) and on existenc ...201526591617
the toxicity of carbofuran to the freshwater rotifer, philodina roseola.in this study, the effects of exposing the rotifer philodina roseola to the pesticide carbofuran were investigated. its range of sensitivity to potassium dichromate, the acute toxicity of active ingredient carbofuran and of carbofuran dosed as its commercial form, furadan(®) 350 sc were determined. chronic toxicity of carbofuran dosed as furadan(®) 350 sc on p. roseola survival and fecundity were also studied. the sensitivity of p. roseola to k2cr2o7 ranged from 29.52 to 64.67 mg l(-1), averagin ...201525588673
density- and trait-mediated effects of a parasite and a predator in a tri-trophic food web.despite growing interest in ecological consequences of parasitism in food webs, relatively little is known about effects of parasites on long-term population dynamics of non-host species or about whether such effects are density or trait mediated. we studied a tri-trophic food chain comprised of (i) a bacterial basal resource (serratia fonticola), (ii) an intermediate consumer (paramecium caudatum), (iii) a top predator (didinium nasutum) and (iv) a parasite of the intermediate consumer (holospo ...201525382389
[relationship between the curve of anesthesia time and the conditions of anesthesia in lumbricus variegatus and paramecium caudatum]. 20155880637
[relation of the thermostability of paramecium caudatum and the concentration of kcl and nacl in the culture medium and the concentration of equilibrated salt solutions]. 20155863661
[relation of the thermostability of paramecium caudatum to the presence of ethyl ether and urea in the medium]. 201514277057
[effect of temperature on the content of ribonucleic acid in paramecium caudatum after roentgen irradiation]. 201514326343
[changes in the fat and glycogen content of paramecium caudatum after ultraviolet irradiation]. 201514093525
[the effect of respiration inhibitors on the survival of the infusorian paramecium caudatum]. 201514070567
transgenic bacillus thuringiensis (bt) rice is safer to aquatic ecosystems than its non-transgenic counterpart.rice lines genetically modified with the crystal toxin genes from bacillus thuringiensis (bt) have experienced rapid development, with biosafety certificates for two bt rice lines issued in 2009. there has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. some studies confirmed that bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in bt ric ...201425105299
draft genome sequences of three holospora species (holospora obtusa, holospora undulata, and holospora elegans), endonuclear symbiotic bacteria of the ciliate paramecium caudatum.we present draft genome sequences of three holospora species, hosted by the ciliate paramecium caudatum; that is, the macronucleus-specific h. obtusa and the micronucleus-specific h. undulata and h. elegans. we investigate functions of orthologous core genes conserved across the three holospora species, which may be essential for the infection and survival in the host nucleus.201425115770
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 ...201425043709
identification of two nickel ion-induced genes, nci16 and pcgst1, in paramecium caudatum.here, we describe the isolation of two nickel-induced genes in paramecium caudatum, nci16 and pcgst1, by subtractive hybridization. nci16 encoded a predicted four-transmembrane domain protein (∼16 kda) of unknown function, and pcgst1 encoded glutathione s-transferase (gst; ∼25 kda) with gst and glutathione peroxidase (gpx) activities. exposing cells to cobalt chloride also caused the moderate upregulation of nci16 and pcgst1 mrnas. both nickel sulfate and cobalt chloride dose dependently induced ...201425001407
inferring the temperature dependence of population parameters: the effects of experimental design and inference algorithm.understanding and quantifying the temperature dependence of population parameters, such as intrinsic growth rate and carrying capacity, is critical for predicting the ecological responses to environmental change. many studies provide empirical estimates of such temperature dependencies, but a thorough investigation of the methods used to infer them has not been performed yet. we created artificial population time series using a stochastic logistic model parameterized with the arrhenius equation, ...201425558365
a biphenyl type two-photon fluorescence probe for monitoring the mitochondrial membrane potential.here we describe the design and synthesis of a bifunctional two-photon fluorescence probe, n,n'-‍dimethyl-4,4'-(biphenyl-2,1-ethenediyl)dipyridinium hexafluorophosphate (bp6). hela, hek293, and paramecium caudatum cells were stained with bp6. bp6 accumulated on the mitochondria of all three cell types when the mitochondrial membrane potential was high. as the mitochondrial membrane potential decreased following the addition of carbonyl cyanide m-chlorophenyl hydrazine, bp6 moved from the mitocho ...201425319070
full-scale bioreactor pretreatment of highly toxic wastewater from styrene and propylene oxide production.the wastewater originating from simultaneous production of styrene and propylene oxide (spo) is classified as highly polluted with chemical oxygen demand level in the range 5965 to 9137mgl(-1)-as well as highly toxic. the dilution factor providing for a 10 percent toxic effect of wastewater samples in a test with paramecium caudatum was 8.0-9.5. biological approach for pretreatment and detoxification of the wastewater under full-scale bioreactor conditions was investigated. the number of suspend ...201425086231
insights into three whole-genome duplications gleaned from the paramecium caudatum genome sequence.paramecium has long been a model eukaryote. the sequence of the paramecium tetraurelia genome reveals a history of three successive whole-genome duplications (wgds), and the sequences of p. biaurelia and p. sexaurelia suggest that these wgds are shared by all members of the aurelia species complex. here, we present the genome sequence of p. caudatum, a species closely related to the p. aurelia species group. p. caudatum shares only the most ancient of the three wgds with the aurelia complex. we ...201424840360
influence of the microbial loop on trophodynamics and toxicity of cadmium complexed by cyanobacterium exudates.cadmium (cd) is an important industrial and toxic metal. its fate and toxicity in the environment may be mediated by association with dissolved organic materials excreted by phytoplankton. the aim of the present study was to investigate the trophodynamics and toxicity of cd complexed with cylindrospermopsis raciborskii exudates in a plankton food chain. the microbial loop involves heterotrophic bacteria as the primary consumer, which is supplemented with a cd-exudate complex. the secondary consu ...201424619145
developing a quick and inexpensive in vitro (non-animal) bioassay for mascara irritation.mascara is a mild irritant that causes a range of medical problems. animal models to predict ocular irritation have, however, been questioned at a number of levels, and there is a continued need to develop in vitro testing methods.201424251684
propulsion of swimming microrobots inspired by metachronal waves in ciliates: from biology to material specifications.the quest for swimming microrobots originates from possible applications in medicine, especially involving navigation in bodily fluids. swimming microorganisms have become a source of inspiration because their propulsion mechanisms are effective in the low-reynolds number regime. in this study, we address a propulsion mechanism inspired by metachronal waves, i.e. the spontaneous coordination of cilia leading to the fast swimming of ciliates. we analyse the biological mechanism (referring to its ...201324103844
[hygienic assessment of waste of soda production].the object of investigations was soda industry waste. slimes are formed at slimes storage which occupy considerable areas and are considered to be the source of permanent impact on the hydrosphere objects. slimes storage placement within settlement boundaries and water protection zone of large watercourses leads to the deterioration of sanitary, hygienic and environmental situation and to the rising of risks to health of communities. waste processing with getting new materials on the base of sod ...201324003694
draft genome sequence of holospora undulata strain hu1, a micronucleus-specific symbiont of the ciliate paramecium caudatum.holospora undulata is a micronucleus-specific symbiont of the ciliate paramecium caudatum. we report here the draft genome sequence of h. undulata strain hu1. this genome information will contribute to the study of symbiosis between h. undulata and the host p. caudatum.201323969064
stochastic environmental fluctuations drive epidemiology in experimental host-parasite metapopulations.environmental fluctuations are important for parasite spread and persistence. however, the effects of the spatial and temporal structure of environmental fluctuations on host-parasite dynamics are not well understood. temporal fluctuations can be random but positively autocorrelated, such that the environment is similar to the recent past (red noise), or random and uncorrelated with the past (white noise). we imposed red or white temporal temperature fluctuations on experimental metapopulations ...201323966645
modelling the dynamics of an experimental host-pathogen microcosm within a hierarchical bayesian framework.the advantages of bayesian statistical approaches, such as flexibility and the ability to acknowledge uncertainty in all parameters, have made them the prevailing method for analysing the spread of infectious diseases in human or animal populations. we introduce a bayesian approach to experimental host-pathogen systems that shares these attractive features. since uncertainty in all parameters is acknowledged, existing information can be accounted for through prior distributions, rather than thro ...201323936351
inactivation of ca2+-induced ciliary reversal by high-salt extraction in the cilia of paramecium.intracellular ca(2+) induces ciliary reversal and backward swimming in paramecium. however, it is not known how the ca(2+) signal controls the motor machinery to induce ciliary reversal. we found that demembranated cilia on the ciliated cortical sheets from paramecium caudatum lost the ability to undergo ciliary reversal after brief extraction with a solution containing 0.5 m kcl. kno(3), which is similar to kcl with respect to chaotropic effect; it had the same effect as that of kcl on ciliary ...201323636433
a new approach for aggregation of paramecium caudatum by nitric oxide.nitric oxide (no) plays a role in thermoregulation and growth of protozoa. this work aimed to add the molecule no in physiology of protozoa in contact with abused narcotic substances.201323467065
estimation of effective concentrations of atp-regenerating enzymes in cilia of paramecium caudatum.the phosphoarginine shuttle system effectively regenerates atp in the cilia of paramecium caudatum. to estimate the effective concentration of atp-regenerating enzymes, we attempted to reconstitute certain atp-regenerating systems within the cilia of intact cortical sheets using exogenous enzymes and high-energy substances. the addition of phosphoenolpyruvate, which is one of the substrates in glycolysis, did not increase the ciliary beat frequency, whereas phosphocreatine together with exogenou ...201322092750
variations and evolution of polyubiquitin genes from ciliates.polyubiquitin genes from seven ciliate species were amplified, cloned and sequenced. it is estimated that strombidium sulcatum, euplotes vannus, e. rariseta and anteholosticha manca have a polyubiquitin gene of 3 repeats, and a. parawarreni, paramecium caudatum and pseudokeronopsis flava 4 repeats. the newly obtained ubiquitins mostly differ from that of humans by 1-5 residues in amino acid sequences. a neighbor-joining tree constructed based on monomeric ubiquitin genes supports the monophyly o ...201322683065
[an experimental study and a mathematical model of interactions in mixed culture of invertebrates and algae in the "producer-consumer" aquatic biotic cycle].an experimental investigation was carried out, and a mathematical model of interaction between invertebrates (infusoria paramecium caudatum and rotifera brachionus plicatilis) and algae (chlorella vulgaris and scenedesmus quadricauda) in the "producer-consumer" aquatic biotic cycle with spatially divided links was constructed. the model describes the dynamics of a mixed culture of infusoria and rotifera in the "consumer" link, when they consume a mixed culture of algae coming from the "producer" ...201315612555
convergent evolution of heat-inducibility during subfunctionalization of the hsp70 gene family.heat-shock proteins of the 70 kda family (hsp70s) are essential chaperones required for key cellular functions. in eukaryotes, four subfamilies can be distinguished according to their function and localisation in different cellular compartments: cytosol, endoplasmic reticulum, mitochondria and chloroplasts. generally, multiple cytosol-type hsp70s can be found in metazoans that show either constitutive expression and/or stress-inducibility, arguing for the evolution of different tasks and functio ...201323433225
resistance of bioparticles formed of phosphate-accumulating bacteria and zeolite to harsh environmental conditions.extreme environmental conditions, such as ph fluctuations, high concentrations of toxicants or grazing of protozoa, can potentially be found in wastewater treatment systems. this study was carried out to provide specific evidence on how 'bioparticles' can resist these conditions. the term 'bioparticle' is used to describe a particle comprising natural zeolitized tuff with a developed biofilm of the phosphate-accumulating bacterial species, acinetobacter junii, on the surface. the bacteria in the ...201323706006
paramecium caudatum enhances transmission and infectivity of mycobacterium marinum and m. chelonae in zebrafish danio rerio.mycobacterial infections in laboratory zebrafish danio rerio are common and widespread in research colonies. mycobacteria within free-living amoebae have been shown to be transmission vectors for mycobacteriosis. paramecium caudatum are commonly used as a first food for zebrafish, and we investigated this ciliate's potential to serve as a vector of mycobacterium marinum and m. chelonae. the ability of live p. caudatum to transmit these mycobacteria to larval, juvenile and adult zebrafish was eva ...201324192000
'candidatus megaira polyxenophila' gen. nov., sp. nov.: considerations on evolutionary history, host range and shift of early divergent rickettsiae."neglected rickettsiaceae" (i.e. those harboured by non-hematophagous eukaryotic hosts) display greater phylogenetic variability and more widespread dispersal than pathogenic ones; yet, the knowledge about their actual host range and host shift mechanism is scarce. the present work reports the characterization following the full-cycle rrna approach (ssu rrna sequence, specific in situ hybridization, and ultrastructure) of a novel rickettsial bacterium, herewith proposed as 'candidatus megaira po ...201323977321
[effect of histamine, phenergan and largactil on protozoan cultures of paramecium caudatum ehrb. (antihistaminic effect of phenergan)]. 201314123363
disturbance of the determination of germinal and somatic nuclei by heat shock in paramecium caudatum.during conjugation of paramecium caudatum, nuclear determination occurs soon after the third postzygotic division: one of the four anterior nuclei becomes the micronucleus and the remaining three degenerate, while four posterior nuclei differentiate into macronuclear anlagen. macronuclear differentiation is supposed to be dependent on a cytoplasmic differentiation factor. in this study, postzygotic cells were subjected to heat shock for 30 min and nuclear changes were observed by staining with c ...201310188260
ingredients for protist coexistence: competition, endosymbiosis and a pinch of biochemical interactions.1. the interaction between mutualism, facilitation or interference and exploitation competition is of major interest as it may govern species coexistence. however, the interplay of these mechanisms has received little attention. this issue dates back to gause, who experimentally explored competition using protists as a model [gause, g.f. (1935) vérifications expérimentales de la théorie mathématique de la lutte pour la vie. actualités scientifiques et industrielles, 277]. he showed the coexisten ...201221831194
interaction of paramecium caudatum and picornaviruses.in our paper we have researched the relationship between picornaviruses (poliovirus, foot-and-mouth disease virus and encephalomyocarditis virus) and ciliata (paramecium caudatum). we show that the number of paramecium in medium sharply increased during coincubation with picornaviruses within 2-5 days. this cannot be explained only by the fact that viruses were nutrient source for paramecium because in case of inactivated viruses the number of infusorians in medium increased a little. at the sam ...201224293830
antimicrobial activity of metal oxide nanoparticles supported onto natural clinoptilolite.the antimicrobial activity of cu(2)o, zno and nio nanoparticles supported onto natural clinoptilolite was investigated in the secondary effluent under dark conditions. after 24h of contact the cu(2)o and zno nanoparticles reduced the numbers of viable bacterial cells of escherichia coli and staphylococcus aureus in pure culture for four to six orders of magnitude and showed consistent 100% of antibacterial activity against native e. coli after 1h of contact during 48 exposures. the antibacterial ...201222677524
coping with temperature at the warm edge--patterns of thermal adaptation in the microbial eukaryote paramecium caudatum.ectothermic organisms are thought to be severely affected by global warming since their physiological performance is directly dependent on temperature. latitudinal and temporal variations in mean temperatures force ectotherms to adapt to these complex environmental conditions. studies investigating current patterns of thermal adaptation among populations of different latitudes allow a prediction of the potential impact of prospective increases in environmental temperatures on their fitness.201222427799
genetic influence on disease spread following arrival of infected carriers.epidemiology in host meta-populations depends on parasite ability to disperse between, establish and persist in distinct sub-populations of hosts. we studied the genetic factors determining the short-term establishment, and long-term maintenance, of pathogens introduced by infected hosts (i.e. carriers) into recipient populations. we used experimental populations of the freshwater ciliate paramecium caudatum and its bacterial parasite holospora undulata. parasite short-term spread (approximately ...201222221658
fluorescence imaging of mitochondria in living cells using a novel fluorene derivative with a large two-photon absorption cross-section.we have examined optical properties of a fluorene derivative with two positively charged substituents, 1,1'- diethyl-4,4'-(9,9-diethyl-2,7-fluorenediyl-2,1-ethanediyl)dipyridinium perchlorate (1), in water. the photoluminescence quantum yield of 1 was relatively high (35%) for use as a fluorescent probe in water. we also examined two-photon absorption (tpa) properties of 1 in methanol. the maximum value of the tpa cross-section (730 gm at 750 nm, 1 gm = 10(-50) cm4 s photon-1 molecule-1) was lar ...201222039816
stage-specific appearance of cytoplasmic microtubules around the surviving nuclei during the third prezygotic division of paramecium.there are six micronuclear divisions during conjugation of paramecium caudatum: three prezygotic and three postzygotic divisions. four haploid nuclei are formed during the first two meiotic prezygotic divisions. usually only one meiotic product is located in the paroral cone (pc) region at the completion of meiosis, which survives and divides mitotically to complete the third prezygotic division to yield a stationary and a migratory pronucleus. the remaining three located outside of the pc degen ...201223266988
quorum sensing and density-dependent dispersal in an aquatic model system.many organisms use cues to decide whether to disperse or not, especially those related to the composition of their environment. dispersal hence sometimes depends on population density, which can be important for the dynamics and evolution of sub-divided populations. but very little is known about the factors that organisms use to inform their dispersal decision. we investigated the cues underlying density-dependent dispersal in inter-connected microcosms of the freshwater protozoan paramecium ca ...201223144882
nanodiamond for intracellular imaging in the microorganisms in vivo.nanodiamond (nd) has great potential for bio labeling and drug delivery. in this work, the biocompatibility and bio labeling of nd are demonstrated via the interaction with cells and microorganisms, protists microorganisms paramecium caudatum and tetrahymena thermophile, in vitro and in vivo. we found the microorganism's living functions are not significantly affected by nd. the nds were found entering the food vacuoles and later excreted by the microorganisms. the 5 nm nd was found more toxic c ...201222815227
prospective guidance in a free-swimming cell.a systems theory of movement control in animals is presented in this article and applied to explaining the controlled behaviour of the single-celled paramecium caudatum in an electric field. the theory-general tau theory-is founded on three basic principles: (i) all purposive movement entails prospectively controlling the closure of action-gaps (e.g. a distance gap when reaching, or an angle gap when steering); (ii) the sole informational variable required for controlling gaps is the relative ra ...201222722544
gene transport and expression by arginine-rich cell-penetrating peptides in paramecium.owing to the cell membrane barriers, most macromolecules and hydrophilic molecules could not freely enter into living cells. however, cell-penetrating peptides (cpps) have been discovered that can translocate themselves and associate cargoes into the cytoplasm. in this study, we demonstrate that three arginine-rich cpps (sr9, hr9 and pr9) can form stable complexes with plasmid dna at the optimized nitrogen/phosphate ratio of 3 and deliver plasmid dna into paramecium caudatum in a noncovalent man ...201121925248
localization of stationary pronuclei during conjugation of paramecium as indicated by immunofluorescence staining.after the third prezygotic division during conjugation of paramecium caudatum, migratory and stationary pronuclei are produced. the migratory pronuclei remain in the paroral region tightly against the conjugating boundaries; while the stationary pronuclei are located beside the migratory pronuclei. to date, however, it is not clear what causes this close side-by-side localization between migratory and stationary pronuclei. in the current study, immunofluorescence staining with monoclonal antibod ...201121842544
the mitochondrial genome sequence of the ciliate paramecium caudatum reveals a shift in nucleotide composition and codon usage within the genus paramecium.despite the fact that the organization of the ciliate mitochondrial genome is exceptional, only few ciliate mitochondrial genomes have been sequenced until today. all ciliate mitochondrial genomes are linear. they are 40 kb to 47 kb long and contain some 50 tightly packed genes without introns. earlier studies documented that the mitochondrial guanine + cytosine contents are very different between paramecium tetraurelia and all studied tetrahymena species. this raises the question of whether the ...201121627782
adaptation of paramecium caudatum to variable conditions of temperature stress.the environment is rarely constant and organisms are exposed to spatial and temporal variation that will impact life-histories. it is important to understand how such variation affects the adaptation of organisms to their local environment. we compare the adaptation of populations of the ciliate paramecium caudatum exposed to constant (23 °c or 35 °c) and temporally variable temperature environments (random daily fluctuations between 23 °c or 35 °c). consistent with theory, our experiment shows ...201121575715
changes in paramecium caudatum (protozoa) near a switched-on gsm telephone.the protozoan paramecium caudatum was examined under normal conditions versus aside a switched-on gsm telephone (900 mhz; 2 watts). exposed individuals moved more slowly and more sinuously than usual. their physiology was affected: they became broader, their cytopharynx appeared broader, their pulse vesicles had difficult in expelling their content outside the cell, their cilia less efficiently moved, and trichocysts became more visible. all these effects might result from some bad functioning o ...201121554102
dynamic behaviour of stationary pronuclei during their positioning in paramecium caudatum.during conjugation of paramecium caudatum, there are two well-known stages when nuclear migration occurs. what happens to the nuclei is closely related to their localisations in cells. the first of these stages is the entrance of one meiotic product into the paroral region. this nucleus survives, while the remaining three outside this area degenerate. the second stage is the antero-posterior localisation of eight synkaryon division products. four posterior nuclei are differentiated into macronuc ...201121497073
new details indicated by different stainings during conjugation of ciliated protozoa paramecium.during conjugation of paramecium caudatum, nuclear events occur in a scheduled program. morphological studies on nuclear behavior during conjugation of p. caudatum have been performed since the end of the 19th century. here we report on new details concerning the conjugation of p. caudatum through the staining of conjugating cells with protargol, carbol fuchsin solution, hoechst 33342 and immunofluorescence labeling with monoclonal antibody of anti-α tubulin. 1) the crescent nucleus is a charact ...201122184025
thermal performance curves of paramecium caudatum: a model selection approach.the ongoing climate change has motivated numerous studies investigating the temperature response of various organisms, especially that of ectotherms. to correctly describe the thermal performance of these organisms, functions are needed which sufficiently fit to the complete optimum curve. surprisingly, model-comparisons for the temperature-dependence of population growth rates of an important ectothermic group, the protozoa, are still missing. in this study, temperature reaction norms of natura ...201121277756
prey-dependent mortality rate: a critical parameter in microbial models.protozoa are key components of a wide range of ecosystems, but ecological models that incorporate these microbes often suffer from poor parameterisation, specifically of top-level predator loss rates. we (1) suggest that top-level predator mortality is prey-dependent, (2) provide a novel approach to assess this response, and (3) illustrate the ecological relevance of these findings. ciliates, paramecium caudatum (prey) and didinium nasutum (predator), were used to evaluate predator mortality at ...201121394608
temporal variation in temperature determines disease spread and maintenance in paramecium microcosm populations.the environment is rarely constant and organisms are exposed to temporal and spatial variations that impact their life histories and inter-species interactions. it is important to understand how such variations affect epidemiological dynamics in host-parasite systems. we explored effects of temporal variation in temperature on experimental microcosm populations of the ciliate paramecium caudatum and its bacterial parasite holospora undulata. infected and uninfected populations of two p. caudatum ...201121450730
[In Process Citation]. 201122168016
[fibrillar actin in the nuclear apparatus of the ciliate paramecium caudatum].due to their nuclear dualism, ciliates provide a good model for studying the role of actin in spatial organization and transcription activity of the nucleus. the actin in the nuclear apparatus of the ciliate paramecium caudatum was studied using fluorescently labeled phalloiodin and indirect immunocytochemistry. fibrillar actin was demonstrated in both of the nuclei. actin was revealed in the chromatin areas, and was often associated with the periphery of the amplified nucleoli in the macronucle ...201121870510
reverse evolution: selection against costly resistance in disease-free microcosm populations of paramecium caudatum.evolutionary costs of parasite resistance arise if genes conferring resistance reduce fitness in the absence of parasites. thus, parasite-mediated selection may lead to increased resistance and a correlated decrease in fitness, whereas relaxed parasite-mediated selection may lead to reverse evolution of increased fitness and a correlated decrease in resistance. we tested this idea in experimental populations of the protozoan paramecium caudatum and the parasitic bacterium holospora undulata. aft ...201122133218
Endosymbionts in Paramecium.Paramecium species are extremely valuable organisms to enable experiments for the reestablishment of endosymbiosis. This is investigated in two different systems, the first with Paramecium caudatum and the endonuclear symbiotic bacterium Holospora species. Although most endosymbiotic bacteria cannot grow outside the host cell as a result of their reduced genome size, Holospora species can maintain their infectivity for a limited time. We found that an 89-kDa periplasmic protein has an important ...201122153895
route of infection of the bacteria holospora elegans and holospora obtusa into the nuclei of paramecium caudatum.the route of infection of two endonucleobiotic bacteria in paramecium caudatum was investigated with the electron microscope. the bacterium holospora elegans specifically infects the micronucleus, whereas holospora obtusa infects the macronucleus. the infectious forms of both bacteria are ingested by the prospective host cell into a phagosome. the bacteria leave the phagosome without destroying its membrane. during their transport to the nuclei the bacteria remain surrounded by host membranes fo ...201123195560
host growth conditions influence experimental evolution of life history and virulence of a parasite with vertical and horizontal transmission.in parasites with mixed modes of transmission, ecological conditions may determine the relative importance of vertical and horizontal transmission for parasite fitness. this may lead to differential selection pressure on the efficiency of the two modes of transmission and on parasite virulence. in populations with high birth rates, increased opportunities for vertical transmission may select for higher vertical transmissibility and possibly lower virulence. we tested this idea in experimental po ...201020163449
experimental evolution of local parasite maladaptation.sign and magnitude of local adaptation in host-parasite systems may vary with ecological, epidemiological or genetic parameters. to investigate the role of host genetic background, we established long-term experimental populations of different genotypes of the protozoan paramecium caudatum, infected with the bacterial parasite holospora undulata. we observed the evolution of an overall pattern of parasite local maladaptation for infectivity, indicating a general coevolutionary disadvantage of th ...201020406349
parasite-mediated protection against osmotic stress for paramecium caudatum infected by holospora undulata is host genotype specific.under certain conditions, otherwise parasitic organisms may become beneficial to their host. parasite-mediated heat and osmotic stress resistance have been demonstrated for paramecium caudatum, infected by several species of parasitic bacteria of the genus holospora. here, using the micronucleus-specific bacterium holospora undulata, we investigate how infection mediates the response of two genotypes (clones 'k8' and 'ven') of p. caudatum to heat (35 °c) and osmotic (0.24% nacl) stress. in contr ...201020722731
parasitic infection reduces dispersal of ciliate host.parasitic infection can modify host mobility and consequently their dispersal capacity. we experimentally investigated this idea using the ciliate paramecium caudatum and its bacterial parasite holospora undulata. we compared the short-distance dispersal of infected and uninfected populations in interconnected microcosms. infection reduced the proportion of hosts dispersing, with levels differing among host clones. host populations with higher densities showed lower dispersal, possibly owing to ...201020961885
perfluorooctanoic acid (pfoa) but not perfluorooctane sulfonate (pfos) showed dna damage in comet assay on paramecium caudatum.persistent perfluorinated organic compounds such as perfluorooctane sulfonate (pfos) and perfluorooctanoic acid (pfoa) are distributed widely in the global environment including wildlife and human. in this study, we investigated the genotoxicity of pfos and pfoa using the novel in vivo comet assay developed for paramecium caudatum. for the comet assay, large nuclei squeezed out of the paramecia with 0.25 m sucrose containing 0.6% triton x-100 were embedded in a layer of agarose gel placed over t ...201021139333
morphological apoptotic characteristics of the post-meiotic micronuclei in paramecium caudatum.in a previous study, the apoptotic degeneration of meiotic products outside the paroral region of paramecium caudatum was indirectly demonstrated by means of "apofluor" staining. in this experiment, conjugating pairs and exconjugants of p. caudatum were stained with either "apofluor" or carbol fuchsin or both to find some direct evidence to demonstrate the apoptotic characteristics of this process. as a result, asynchronous meiotic nuclear degeneration was observed. furthermore, a number of addi ...201020494562
extreme heterogeneous composition of the paramecium caudatum macronuclear genomic dna between hemoglobin and nucleosome assembly protein-1 genes.the intergenic region between the hemoglobin (hb) and nucleosome assembly protein-1 (nap-1) genes in the paramecium caudatum macronuclear genome was previously found to be heterogeneously composed. cloning of this intergenic region from the macronuclear genomic dna identified four unique dna fragments of different sizes. sequencing of the cloned fragments revealed extreme heterogeneity and characteristics of both internal eliminated sequence (ies) and imprecise internal deletion sequences (iidss ...201020410661
cytotoxicity assessment of monocrotophos in paramecium caudatum and oxytricha fallax.experiments were conducted to evaluate the toxic effects ofmonocrotophos in ciliate models paramecium caudatum and oxytricha fallax. in acute toxicity studies higherconcentrations of monocrotophos caused marked increase in mobility of cells exhibiting rocking movements within two mins of exposure but were decreased after 30 mins. lc50 value by mortality curve for 3 hr acute toxicity test of oxytricha fallax and paramecium caudatum was found 307.744 +/- 33.27 mg l(-1) and 332.284 +/- 57.52 mg l(- ...201021387909
the presence of chimeric dna consisting of 5' regions of the hemoglobin and nucleosome assembly protein-1 genes in paramecium caudatum macronuclear genomic dna.we detected an unexpected small-sized dna fragment during polymerase chain reaction (pcr) analysis of the heterogeneity of a macronuclear intergenic region of paramecium caudatum. southern blotting of total genomic dna with the pcr product as a probe indicated that the small-sized dna fragment constituted part of the macronuclear genome. sequencing revealed that the pcr product was a chimeric dna structure that may be generated by tail-to-tail fusion of the 5' region of the hemoglobin (hb) gene ...200919798919
[evaluation of the toxicity of returned and natural waters by biotesting techniques].the background of the development of a new procedure for calculating the value of water toxicity, by using the test object--paramecium caudatum infusoria is successively set forth. a series of experiments analyzing the toxic effect of water on the infusoria have been carried out by nongraphic method using the probit analysis. the high coefficient of a correlation between the unified toxicity values obtained by an example of various test objects allows adequate comparison of these results, which ...200919642552
studies of paramecium caudatum by means of scanning electron microscope and projection x-ray microscope.samples of paramecium caudatum are observed by means of a scanning electron microscope (sem) and a projection x-ray microscope (xrm) with computer tomography (ct) function. the samples are fixed with two kinds of fixatives, glutaraldehyde and osmium-tetra oxide acid. after the fixation and replacement procedure with t-buthyl alcohol, the samples followed by a freeze drying, well retain their structures. surface structures, cilia and microfibrillar systems including infraciliary lattice structure ...200919581701
novel features of computer-simulated clonal life of paramecium caudatum.the clone of the ciliated protozoan paramecium caudatum has the immaturity period of about 60 fissions and the lifespan of about 600 fissions. these life cycle figures have been depicted through laboratory experiments that allow continuous cell divisions for hundreds, which never occur in nature. we here constructed the nature-mimicking model culture that alternated the log- and stationary phases to allow conjugation, and computer-simulated the age structure modifying parameters such as cell dis ...200919490859
a long-term conservation tool for cell characteristics: cryopreservation of paramecium caudatum. 200919427813
cellular communication through light.information transfer is a fundamental of life. a few studies have reported that cells use photons (from an endogenous source) as information carriers. this study finds that cells can have an influence on other cells even when separated with a glass barrier, thereby disabling molecule diffusion through the cell-containing medium. as there is still very little known about the potential of photons for intercellular communication this study is designed to test for non-molecule-based triggering of tw ...200919340303
actin-based mechanism of holospora obtusa trafficking in paramecium caudatum.holospora obtusa, an alpha-proteobacterium, is an obligate endonuclear pathogen of the ciliate paramecium caudatum. it is engulfed by the host cell in the course of phagocytosis but soon escapes from the phagosome and is transported across the host cell cytoplasm to the paramecium macronucleus. electron microscopy reveals a comet-like tail resembling that of listeria trailing after h. obtusa in the host cytoplasm. in this study we investigated the role of the host cell actin and arp3 in the proc ...200919231281
effects of shortened host life span on the evolution of parasite life history and virulence in a microbial host-parasite system.ecological factors play an important role in the evolution of parasite exploitation strategies. a common prediction is that, as shorter host life span reduces future opportunities of transmission, parasites compensate with an evolutionary shift towards earlier transmission. they may grow more rapidly within the host, have a shorter latency time and, consequently, be more virulent. thus, increased extrinsic (i.e., not caused by the parasite) host mortality leads to the evolution of more virulent ...200919320981
the effects of anabaena spiroides exopolysaccharides on copper accumulation in an aquatic food chain.the influence of anabaena spiroides exopolysaccharides (eps) on copper speciation (total dissolved, particulate and free cu(2+) ions) and bioavailability in aquatic organisms was investigated. bacteria were used as the first trophic level, paramecium caudatum (protozoan) as the second and the copepod cyclopoid metacyclops mendocinus as the third level. the organisms were obtained from a freshwater reservoir and held under continuous laboratory controlled conditions. freshwater media containing e ...200919447509
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