The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Martina Schrallhammer - One of the best experts on this subject based on the ideXlab platform.
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tracing the role of r bodies in the killer trait absence of toxicity of r body producing recombinant e coli on Paramecia
European Journal of Protistology, 2012Co-Authors: Michael Schweikert, Hansdieter Gortz, Martina Schrallhammer, Stefano Galati, Josef Altenbuchner, Giulio PetroniAbstract:R-bodies are coiled proteinaceous ribbons produced by Paramecium endosymbionts belonging to the genus Caedibacter. These intracellular bacteria confer upon their hosts a phenomenon called the killer trait. It is the ability to kill symbiont-free competitors called sensitives. The R-body is the crucial element of this process, but despite many efforts, the actual role of R-bodies in killing sensitive Paramecia is still not satisfactory clarified. The open question is whether the R-body acts as transmitter for a yet unidentified toxin or whether it directly kills sensitive Paramecia having intrinsic cytotoxic effects. In the present study, this problem is addressed by heterologous expression of Caedibacter taeniospiralis R-body in Escherichia coli followed by a detailed analysis of its potential intrinsic toxic effect on feeding sensitive Paramecium tetraurelia. Using this approach, we can exclude any eventual effects of additional, unidentified factors produced by C. taeniospiralis and thus observe the impact of the recombinant R-body itself. No cytotoxic effects of recombinant R-bodies were detected following this approach, strengthening the hypothesis that R-bodies act as releasing system for an unidentified C. taeniospiralis toxin.
Yoshiomi Takagi - One of the best experts on this subject based on the ideXlab platform.
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catalase is the bacteria derived detoxifying substance against Paramecia killing toxin in wheat grass powder infusion
Journal of Eukaryotic Microbiology, 2003Co-Authors: Naomi Mizobuchi, Kumio Yokoigawa, Terue Harumoto, Hiromi Fujisawa, Yoshiomi TakagiAbstract:Paramecium cells are usually cultured in a wheat grass powder infusion inoculated with Klebsiella pneumoniae. However, non-bacterized wheat grass powder infusion is toxic to Paramecia, and bacteria-derived substance detoxifies the toxic substance. Here, the detoxifying substance from K. pneumoniae, which was found to be proteinaceous, was purified to homogeneity. The protein had an apparent molecular mass of about 200 kDa by gel filtration and 92 kDa by SDS-polyacrylamide gel electrophoresis. Although the amino acid sequence of the amino terminal region did not show a high sequence homology with any reported proteins, amino acid sequences of internal regions of the protein were nearly identical to catalase HPII from Escherichia coli. When the wheat grass powder infusion was treated at 25 °C for 1 h with commercially available catalase from bovine liver, the toxicity of the infusion against Paramecia was completely abolished. The initial concentration of hydrogen peroxide in the wheat grass powder infusion was about 30 μM and was completely decomposed by the catalase treatment. Therefore, the toxic substance in the wheat grass powder infusion and the detoxifying substance from K. pneumoniae are considered as hydrogen peroxide and catalase, respectively.
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ectosymbiotic role of food bacteria for paramecium bacterial detoxification of Paramecia killing toxin contained in wheat grass powder
Zoological Science, 2000Co-Authors: Yumiko Tokusumi, Yoshiomi TakagiAbstract:Bacterized plant infusion is a popular culture medium for Paramecium, using Klebsiella pneumoniae for the bacterium and Wheat Grass Powder (WGP) for the plant. It has been thought that WGP plays a role in the growth of bacteria, which in turn serve as the direct food for Paramecia. However, we found that bacteria suspended in saline solution were unable to support the growth of Paramecia. WGP including no bacteria was able to support neither the growth nor the survival of Paramecia; instead, it killed Paramecia. The killing effect of the WGP-derived substance(s), estimated to be of molecular weight less than 1,000, was abolished when bacteria were once grown in the WGP and then eliminated, suggesting that bacteria might change the toxic substance into an inactive form. This inactivation of the toxic substance may be caused either by metabolization inside of the bacteria or by neutralization by means of bacteria-derived substance outside of the bacteria. The second alternative is likely, because Paramecia were able to survive and grow in the WGP medium containing a sufficient amount of dead bacteria killed by formalin or kanamycin. Dead bacteria killed by autoclaving were ineffective, probably because bacterial contents were lost. These findings revealed an ectosymbiotic role of bacteria; they confer benefits upon Paramecia not only as food but also as machinery to detoxicate a plant toxin.
Masahiro Fujishima - One of the best experts on this subject based on the ideXlab platform.
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symbiotic chlorella variabilis incubated under constant dark conditions for 24 hours loses the ability to avoid digestion by host lysosomal enzymes in digestive vacuoles of host ciliate paramecium bursaria
FEMS Microbiology Ecology, 2014Co-Authors: Yuuki Kodama, Masahiro FujishimaAbstract:Endosymbiosis between symbiotic Chlorella and alga-free Paramecium bursaria cells can be induced by mixing them. To establish the endosymbiosis, algae must acquire temporary resistance to the host lysosomal enzymes in the digestive vacuoles (DVs). When symbiotic algae isolated from the alga-bearing Paramecia are kept under a constant dark conditions for 24 h before mixing with the alga-free Paramecia, almost all algae are digested in the host DVs. To examine the cause of algal acquisition to the host lysosomal enzymes, the isolated algae were kept under a constant light conditions with or without a photosynthesis inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea for 24 h, and were mixed with alga-free Paramecia. Unexpectedly, most of the algae were not digested in the DVs irrespective of the presence of the inhibitor. Addition of 1 mM maltose, a main photosynthetic product of the symbiotic algae or of a supernatant of the isolated algae kept for 24 h under a constant light conditions, did not rescue the algal digestion in the DVs. These observations reveal that unknown factors induced by light are a prerequisite for algal resistance to the host lysosomal enzymes.
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Four important cytological events needed to establish endosymbiosis of symbiotic Chlorella sp. to the alga-free Paramecium bursaria
2011Co-Authors: Yuuki Kodama, Masahiro FujishimaAbstract:SUMMARY Each symbiotic Chlorella of the ciliate Paramecium bursaria is enclosed in a perialgal vacuole (PV) derived from the host digestive vacuole (DV) to protect from lysosomal fusion. Irrespective of the mutual relationships between P. bursaria and their symbiotic algae, the alga-free Paramecia and symbiotic algae still have an ability to grow independently and can be experimentally reinfected by mixing them. This phenomenon provides an excellent opportunity to elucidate cell-to-cell interactions between protozoa and algae during establishment of the secondary endosymbiosis. However, the detailed algal reinfection process had been unclear. Therefore, using pulse-label of the alga-free Paramecia with the isolated symbiotic algae and chase method, we found four important cytological events needed to establish endosymbiosis. (1) 3 min after mixing, some algae show resistance to the host lysosomal enzymes in the DVs even if the digested ones are coexisted. (2) 30 min after mixing, the alga starts to leave from the DV to appear in the cytoplasm by budding of the DV membrane. (3) Within 15 min after the algal appearance in the cytoplasm, the vacuole enclosing a single green alga differentiates into the PV from the DV, which gives protection from the host lysosomal fusion. (4) After that, the alga localizes beneath the host cell cortex. At about 24 h after mixing, the alga increases by cell division and establishes endosymbiosis. In this review article, we describe our recent studies on the four events during the algal reinfection process.
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micronucleus specific bacterium holospora elegans irreversibly enhances stress gene expression of the host paramecium caudatum
Journal of Eukaryotic Microbiology, 2008Co-Authors: Manabu Hori, Kimiko Fujii, Masahiro FujishimaAbstract:The bacterium Holospora is an endonuclear symbiont of the ciliate Paramecium. Previously, we reported that Paramecia bearing the macronuclear-specific symbiont Holospora obtusa survived better than symbiont-free Paramecia, even under high temperatures unsuitable for growth. The Paramecia with symbionts expressed high levels of hsp70 mRNAs even at 25 degrees C, a usual growth temperature. We report herein that Paramecia bearing the micronuclear-specific symbiont Holospora elegans also acquire the heat-shock resistance. Even after the removal of the bacteria from the hosts by treatment with penicillin, the resulting aposymbiotic Paramecia nevertheless maintained their heat shock-resistant nature for over 1 yr. Like symbiotic Paramecia, these aposymbiotic Paramecia also expressed high levels of both hsp60 and hsp70 mRNAs even at 25 degrees C. Moreover, analysis by fluorescent in situ hybridization with a probe specific for Holospora 16S rRNA revealed that the 16S rRNA of H. elegans was expressed around the nucleoli of the macronucleus in the aposymbiotic cells. This result suggests the possible transfer of Holospora genomic DNA from the micronucleus into the macronucleus in symbiotic Paramecia. Perhaps this exogenous DNA could trigger the aposymbiotic Paramecia to induce a stress response, inducing higher expression of Hsp60 and Hsp70, and thus conferring heat-shock resistance.
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the endosymbiotic bacterium holospora obtusa enhances heat shock gene expression of the host paramecium caudatum
Journal of Eukaryotic Microbiology, 2003Co-Authors: Manabu Hori, Masahiro FujishimaAbstract:The bacterium Holospora obtusa is a macronuclear-specific symbiont of the ciliate Paramecium caudatum. H. obtusa-bearing Paramecia could survive even after the cells were quickly heated from 25 °C to 35 °C. To determine whether infection with H. obtusa confers heat shock resistance on its host, we isolated genes homologous to the heat shock protein genes hsp60 and hsp70 from P. caudatum. The deduced amino acid sequences of both cDNAs were highly homologous to hsp family sequences from other eukaryotes. Competitive PCR showed that H. obtusa-free Paramecia expressed only trace amounts of hsp60 and hsp70 mRNA at 25 °C, but that expression of hsp70 was enhanced immediately after the cells were transferred to 35 °C. H. obtusa-bearing Paramecia expressed high levels of hsp70 mRNA even at 25 °C and the level was further enhanced when the cells were incubated at 35 °C. In contrast, the expression pattern of hsp60 mRNA was the same in H. obtusa-bearing as in H. obtusa-free Paramecia. These results indicate that infection with its endosymbiont can confer a heat-shock resistant nature on its host cells.
Hiroshi Hosoya - One of the best experts on this subject based on the ideXlab platform.
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Arrest of Cytoplasmic Streaming Induces Algal Proliferation in Green Paramecia
2016Co-Authors: Toshiyuki Takahashi, Toshikazu Kosaka, Yohji Shirai, Hiroshi HosoyaAbstract:A green ciliate Paramecium bursaria, bearing several hundreds of endosymbiotic algae, demonstrates rotational microtubule-based cytoplasmic streaming, in which cytoplasmic granules and endosymbiotic algae flow in a constant direction. However, its physiological significance is still unknown. We investigated physiological roles of cytoplasmic streaming in P. bursaria through host cell cycle using video-microscopy. Here, we found that cytoplasmic streaming was arrested in dividing green Paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming. Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle. Thus, cytoplasmic streaming may control the algal proliferation in P. bursaria. Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming. This is a first report to suggest that cytoplasmic streaming controls proliferation of eukaryotic cells
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a new bioassay for toxic chemicals using green Paramecia paramecium bursaria
2005Co-Authors: M Tanaka, Toshikazu Kosaka, Tomonori Kawano, Takashi Kadono, Manabu Kunimoto, Y Ishizaka, H Tosuji, N Hosoya, Naohisa Nishihara, Hiroshi HosoyaAbstract:We designed a new toxic bioassay using the green Paramecia Paramecium bursaria as testing organism. P. bursaria is a unicellular organism that occurs widely in rivers and ponds. Since P. bursaria uses metabolites of endosymbiotic green algae in the cytoplasm as a nutritive source, culturing P. bursaria is much easier than culturing mammalian cells. The use of P. bursaria will thus make quicker and more convenient evaluation of toxicity of various polluting chemicals. Here, we selected thirty-two pollutants such as pesticides, toxic metals and polycyclic aromatic hydrocarbons. Those substances were added at various concentrations to the culture medium of Paramecia. Then the IC50 values, defined as the concentrations of chemicals inhibiting the growth of organisms by 50%, obtained for both Paramecia and mammalian cell cultures were compared. We found that Paramecia were much highly sensitive to some chemicals such as methylmercury chloride and mercuric chloride, compared to cultured mammalian cells. We conclude that P. bursaria is one of the best organism for assessing the effect of chemical pollutants in the aqueous environment.
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green Paramecia as an evolutionary winner of oxidative symbiosis a hypothesis and supportive data
Zeitschrift für Naturforschung C, 2004Co-Authors: Tomonori Kawano, Toshikazu Kosaka, Takashi Kadono, Hiroshi HosoyaAbstract:A single cell of the green Paramecia (Paramecium bursaria) harbors several hundreds of endo-symbiotic Chlorella-like algae in its cytoplasm. Removal of algae from the host organism and re-association of ex-symbiotic host Paramecia with ex-symbiotic algae can be experimentally demonstrated in the laboratory. However, the mechanism precisely governing the alga-protozoan association is not fully understood, and the origin of symbiosis in the evolutionary view has not been given. Here, we propose the possible biochemical models (models 1 and 2) explaining the co-evolution between Paramecium species and algal symbionts by pointing out that algal photosynthesis in the host Paramecia plays a dual role providing the energy source and the risk of oxidative damage to the host. Model 1 lays stress on the correlation between the (re)greening ability of the Paramecia and the tolerance to oxidative stress whereas model 2 emphasizes the cause of evolutionary selection leading to the emergence of Paramecium species tolerant against reactive oxygen species.
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use of paramecium species in bioassays for environmental risk management determination of ic50 values for water pollutants
Journal of Health Science, 2003Co-Authors: Norikazu Miyoshi, Toshikazu Kosaka, Tadao Takahashi, Tomonori Kawano, Miho Tanaka, Takashi Kadono, Manabu Kunimoto, Hiroshi HosoyaAbstract:Effect of chemical water pollutants on the growth of two Paramecium species (Paramecium caudatum and Paramecium trichium) were examined. The chemicals used as model chemical pollutants include organic solvents, potential carcinogens, mutagens, metabolic modulators, herbicides, insecticides, fungicides, antimicrobials, heavy metals, and heavy metal-containing chemicals. In this study, the IC50 values indicating the concentration of substances inhibiting the proliferation of Paramecium cells by 50% were used instead of the LD50 value, which indicates the dose of substances killing half the population of organisms, since the former is a more sensitive parameter for assessing the toxicity of substances at lower concentrations. Among 25 chemicals examined, di-(2-ethylhexyl)phthalate, potassium dichromate, 2,4-dichlorophenoxy acetic acid, and paraquat stimulated the growth of Paramecia depending on the concentrations used. Dimethyl sulfoxide and formaldehyde were shown to be inert to Paramecia in the range of concentrations (up to 1%, v/v) used here. Other chemicals were shown to inhibit the growth of the Paramecia and thus the IC50 values for those chemicals were determined. Our data presented here may be a useful reference for assessing the impact of water pollutants on aqueous microecosystems consisting of various microorganisms including protozoa.
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complete elimination of endosymbiotic algae from paramecium bursaria and its confirmation by diagnostic pcr
Acta Protozoologica, 2002Co-Authors: Miho Tanaka, Toshikazu Kosaka, Tomonori Kawano, Takashi Kadono, Maki Muratahori, Takashi Yamada, Hiroshi HosoyaAbstract:Summary. The green paramecium, Paramecium bursaria, has several hundred green algae in the cytoplasm. Symbiotic algae can be removed from their host cells by treatment with a herbicide, paraquat. The presence of symbiotic algae in P. bursaria can be microscopically examined by detecting the red fluorescence of the algal chlorophyll. However, etiolated algae could not be detected by fluorescent microscopic analyses. Therefore, the absence of symbiotic algae should be confirmed by examining the presence or absence of algal DNA in P. bursaria. In this study, we tried to detect the DNA of symbiotic algae by polymerase chain reaction (PCR) using plant genome-specific primers designed to amplify the DNA sequence in the ribulose-1,5-bisphosphate carboxylase small subunit (rbcS) encoding gene. Using this technique, it was confirmed that the DNA of endosymbiotic algae was absent in paraquat-treated Paramecia.
Tomonori Kawano - One of the best experts on this subject based on the ideXlab platform.
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mitigation of copper toxicity by dna oligomers in green Paramecia
Plant Signaling & Behavior, 2015Co-Authors: Hiroshi Takaichi, Diego Comparini, Junichiro Iwase, Francois Bouteau, Stefano Mancuso, Tomonori KawanoAbstract:Impact of transition metals which catalyze the generation of reactive oxygen species (ROS), on activation of cell death signaling in plant cells have been documented to date. Similarly in green Paramecia (Paramecium bursaria), an aquatic protozoan species harboring symbiotic green algae in the cytoplasm, toxicities of various metallic ions have been documented. We have recently examined the effects of double-stranded GC-rich DNA fragments with copper-binding nature and ROS removal catalytic activity as novel plant cell-protecting agents, using the suspension-cultured tobacco cells. Here, we show that above DNA oligomers protect the cells of green Paramecia from copper-induced cell death, suggesting that the phenomenon firstly observed in tobacco cells is not limited only within higher plants but it could be universally observable in wider range of organisms.
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single cell traffic of swimming green Paramecia on microchips with micro flow channels fabricated by micro casting
Advanced Materials Research, 2014Co-Authors: Kohei Otsuka, Sayaka Maruta, Atsuko Noriyasu, Kohji Nakazawa, Tomonori KawanoAbstract:Members of Paramecium species are often referred to as “swimming neurons or sensory cells” applicable to micro-biorobotics or BioMEMS (biological micro-electro-mechanical systems). Paramecium bursaria known as green Paramecia is an unicellular organism that lives widely in fresh water environments such as rivers and ponds. Recent studies have suggested that in vivo cellular robotics using the living cells of green Paramecia as micro-machines controllable under electrical, optical and magnetic signals, has a variety of engineering applications such as transportation of micro-sized particles (ingested within the cells) in the capillary systems. In the present study, we aimed to test if the swimming environment of green Paramecia can be implementable on microchips. For this purpose, the series of microchips were prepared for cellular swimming platform for green Paramecia through fabrication of poly(methyl methacrylate) master plates using the programmable micro-milling system followed by polydimethylsiloxane-based micro-casting. Finally, microchips equipped with optimally sized micro-flow channels for allowing the single cell traffic by swimming green Paramecia were successfully prepared, and thus further studies for application of green paramecium cells in BioMEMS are encouraged.
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enhanced microsphere transport in capillary by conditioned cells of green Paramecia used as living micromachines controlled by electric stimuli
2012Co-Authors: Shunsuke Furukawa, Tomonori KawanoAbstract:Some researchers have described the cells of Paramecium species as “swimming sensory cells” or “swimming neurons” applicable to micro-biorobotics and biological micro-electromechanical systems (BioMEMS). Paramecium species including green Paramecia (Paramecium bursaria) migrate towards the anodic electrode when exposed to an electric field. This type of cellular movement is known as galvanotaxis. Because the ideal micromachines designed for microparticle transport must have a capacity for loading certain numbers of particles, P. bursaria was chosen as a model organism. In this study, we show enhanced microparticle transport by overcoming (i) the particle size limitation for the cell-mediated transport of microspheres of up to ca. 10 μm size (doubling the size of particles ever reported) and (ii) the limit of cellular migration distance manifested by galvanotactically stimulated cells.
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oxidative stress mediated development of symbiosis in green Paramecia
2010Co-Authors: Tomonori Kawano, Takashi Kadono, Kanami IrieAbstract:Single cells of Paramecium bursaria (often referred to as green Paramecia) harbor in its cytoplasm several hundred cells of green algae, which are morphologically and genetically almost identical to Chlorella species. P. bursaria serves as an excellent experimental model for studying the nature of endosymbiosis in which one species propagates inside the cells of other species under precise control through chemical communication between the symbiotic partners. This chapter focuses on the impact of oxidative stress due to algal photosynthesis on the behavior of hosting ciliate and the fate of symbiotic system. In fact, some of alga-derived chemicals including the members of reactive oxygen species (ROS) are apparently threatening the host cells, besides their beneficial supply with nutrients. When the ROS production by the symbiotic algae was experimentally promoted, the excretion of algae from the host cells was highly stimulated. This suggests a scenario in which the host cell bodies in P. bursaria positively eliminate the algae that are the sources of photochemical ROS production. By doing so, the host cells possibly survive by avoiding the risk of internal oxidation when the levels of oxidative stress were high enough to damage the host cells. This type of loose symbiosis between algal cells and the ciliate may support a coevolution process leading to highly tolerant host cell species that are capable of optimizing energy gain from the oxidative symbiosis. We present also a case of symbiosis distortion, which causes unregulated growth of algae.
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Inhibition of anodic galvanotaxis of green Paramecia by T-type calcium channel inhibitors.
Zeitschrift fur Naturforschung. C Journal of biosciences, 2007Co-Authors: Miki Aonuma, Takashi Kadono, Tomonori KawanoAbstract:Calcium ion (Ca2+) is one of the key regulatory elements for ciliary movements in the Paramecium species. It has long been known that members of Paramecium species including green Paramecia (Paramecium bursaria) exhibit galvanotaxis which is the directed movement of cells toward the anode by swimming induced in response to an applied voltage. However, our knowledge on the mode of Ca2+ action during green Paramecia anodic galvanotactic response is still largely limited. In the present study, quantification of anodic galvanotaxis was carried out in the presence and absence of various inhibitors of calcium signaling and calcium channels. Interestingly, galvanotactic movement of the cells was completely inhibited by a variety of Ca2+-related inhibitors. Such inhibitors include a Ca2+ chelator (EGTA), general calcium channel blockers (such as lanthanides), inhibitors of intracellular Ca2+ release (such as ruthenium red and neomycin), and inhibitors of T-type calcium channels (such as NNC 55-0396, 1-octanol and Ni2+). However, L-type calcium channel inhibitors such as nimodipine, nifedipine, verapamil, diltiazem and Cd2+ showed no inhibitory action. This may be the first implication for the involvement of T-type calcium channels in protozoan cellular movements.
