| [effect of local uv irradiation of the generative nuclei of paramecium caudatum on the sexual functions of the cells]. | a study has been made of the functional pattern of the micronucleus (mi) during the sexual process in ciliates paramecium caudatum which are descendants of those individuals whose mi was locally irradiated with uv in dose of 3060 erg/mm2. it was demonstrated that these descendants (cells of uv-clones) were able to enter into the sexual process whatever morphological type of their mi might be. in 4 of 14 tested clones, the initial mating type got changed for the opposite one, which may be associa ... | 1979 | 432969 |
| [photoreactivation of cells and phages injuried by ultraviolet radiation in the ecological long-wave band]. | photoreactivation (pr) was measured after inactivation by far (254 nm), middle (300-315 nm) and near (315-400 nm) uv radiation of paramecium caudatum and 8 strains of escherichia coli differing in pr and dark repair capability. pr volume was high and practically the same after irradiation by far and middle uv, but pr was not observed in near uv-inactivated cells of all the strains. it is proposed that pyrimidine dimers are not significant in near uv lethal lesions in cells, as near uv-irradiated ... | 1979 | 462548 |
| 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 |
| complement consumption in fresh blood sera by double culture of paramecium caudatum and aerobacter cloacae compared with survival and stage of disease in some malignant tumors in man. | using the complement consumption test by double culture of paramecium caudatum and aerobacter cloacae (dpa) as antigen we examined blood sera and compared survival rates and stage of disease in 124 patients with carcinoma of cervix uteri, corpus uteri, ovaries and breast. the evidence suggests that bacteria aerobacter cloacae constitute the proper antigenically effective substances of dpa. the intensity of reaction and therapy the relative titres of antibodies detected by the test were expressed ... | 1976 | 1084486 |
| [symbiotic bacteria of the macronucleus of paramecium caudatum]. | particles of a newly described endosymbiont of paramecium caudatum, clone m-115, here referred to as iota--particles, are gram--negative bacteria. the symbionts are only present within macronuclei and not in the cytoplasm or in the micronuclei. the cells of clone m-115 iota do not display any killer-effect when mixed with "clean" cultures of paramecia. in life cycle of the symbiont, there is an alternation of two morphological forms: a spindle-shaped form 2.0--2.5 microns long and a rod-shaped f ... | 1975 | 1118907 |
| [characteristics of the cytodifferentiation of omega-particle symbiotic bacteria from the micronucleus of paramecium caudata clone m1-48]. | the structure of the omega-particle-bacteria, growing in the micronucleus of paramecium caudatum (ciliata, protozoa), was studied by electrom microscopy in the course of their life cycle. the cytoplasm of the spindle-shaped vegetative cells contains a large number of dense particles and transparent regions comprising the fibrillar material. such cells, via several intermediate stages, are transformed into elongated twisted cells that are regarded as spores. the spore consists of two parts: homog ... | 1975 | 1160642 |
| [effect of local uv microirradiation on the nuclear apparatus and cytoplasm of the infusorian paramecium caudatum]. | the work is the first attempt to study nuclear dualism of ciliates with ultraviolet microbeam (uv-beam), which was not applied earlier for these purposes. the special advantage of the uv-beam is that it allow to inactivate selectively of the particular elements of nuclear apparatus of living ciliates is to observe consequences of operation on distant descendants of irradiated cell. on paramecium caudatum the ways of uv-beam have been devised specifically. the original rotocompression chamber was ... | 1975 | 1166524 |
| [effect of a varying concentration of boron on the tempo of paramecium caudatum multiplication depending on the temperature of the medium]. | the rate of multiplication of paramecium caudatum was studied using individual cultures with media containing 0.001, 0.005, 0.008 and 0.01% borate, resp. at room temperature (20--21 degrees c) with two first concentrations of boron, the ciliates multiply normally over 4 months often surpassing the multiplication rate of the control line. with the increase of boron concentration up to 0.008%, the division rate in paramecia decreases significantly, reaching the control rate only by the end of the ... | 1975 | 1166527 |
| the interface between air and water: a perturbation source eliciting adaptive behaviour in ciliates. | interference with the water-air interface, both direct (by contact with a flat, rigid surface) and indirect (by inducing a meniscus) caused the ciliated protozoa we investigated to actively collect in the water column or on the substrate directly under the area of altered surface tension. a crowding effect is observed in this "rest area" reaching plateau values within one hour after onset of the experiment. the simple experimental procedures described here induced analogous behaviour in both par ... | 1992 | 1403987 |
| myoglobin in a cyanobacterium. | myoglobin was found in the nitrogen-fixing cyanobacterium nostoc commune. this cyanobacterial myoglobin, referred to as cyanoglobin, was shown to be a soluble hemoprotein of 12.5 kilodaltons with an amino acid sequence that is related to that of myoglobins from two lower eukaryotes, the ciliated protozoa paramecium caudatum and tetrahymena pyriformis. cyanoglobin is encoded by the glbn gene, which is positioned between nifu and nifh-two genes essential for nitrogen fixation-in the genome of nost ... | 1992 | 1609281 |
| identification in situ and phylogeny of uncultured bacterial endosymbionts. | the use of koch's technique to isolate bacteria in pure cultures has enabled thousands of bacterial species to be characterized. but for the many microorganisms that have never been cultivated, dna amplification in vitro using the polymerase chain reaction is now making their genes accessible. here we use this technique to study bacteria of the genus holospora, which live in ciliates and whose phylogenetic relationship has remained unknown because they are impossible to cultivate. species of hol ... | 1991 | 1709451 |
| molecular cloning of the cdna for the major hemoglobin component from paramecium caudatum. | nucleotide sequence of the cdna for the major hemoglobin component of paramecium caudatum was determined. an oligonucleotide was synthesized on the basis of the amino acid sequence, and the paramecium cdna library constructed in phage lambda gt11 was screened with it. three positive clones, of which insert sizes were 0.4, 0.6, and 0.9 kbp, were obtained. sequence analysis made clear that the 0.4-kbp cdna retains a full length of the nucleotides encoding 116 amino acid residues, and that in the c ... | 1992 | 1731779 |
| identification and localization of major stage-specific polypeptides of infectious holospora obtusa with monoclonal antibodies. | with the help of monoclonal antibodies (mabs) we investigated the occurrence of six polypeptides throughout parts of the life cycle of holospora obtusa, a bacterium infecting the macronucleus of the ciliate paramecium caudatum. the polypeptides of interest formed major bands in the protein pattern of the infectious form (if) of h. obtusa. all mabs used recognized individual polypeptide bands of the if proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. three polypept ... | 1991 | 1856177 |
| rhizocticin a, an antifungal phosphono-oligopeptide of bacillus subtilis atcc 6633: biological properties. | rhizocticin a, the main component of the antifungal, hydrophilic phosphono-oligopeptides of bacillus subtilis atcc 6633, was used for sensitivity testing and experiments into the molecular mechanism of the antibiotic action. budding and filamentous fungi as well as the cultivated nematode caenorhabditis elegans were found to be sensitive, whereas bacteria and the protozoon paramecium caudatum were insensitive. rhizoctonia solani was inhibited in agar dilution tests but not in diffusion tests. th ... | 1990 | 2110446 |
| changes in fine structure and polypeptide pattern during development of holospora obtusa, a bacterium infecting the macronucleus of paramecium caudatum. | the development of the bacterium holospora obtusa, which infects the macronucleus of paramecium caudatum, was investigated in the course of a new infection from the infectious form into the reproductive form and vice versa. in parallel with a complete structural reorganization of the bacterium, the protein pattern changed gradually in this development. during the differentiation of the infectious form into the reproductive form, the voluminous periplasm was gradually reduced and the cytoplasm ex ... | 1990 | 2211504 |
| protozoan myoglobin from paramecium caudatum. its unusual amino acid sequence. | a protozoan myoglobin (or monomeric hemoglobin) was isolated from paramecium caudatum, and its complete amino acid sequence determined. it consists of 116 amino acid residues with a molecular mass of 12,565 daltons, this being much smaller than sperm whale myoglobin by 37 residues and even smaller than a bacterial hemoglobin from vitreoscilla by 30 residues in terms of the monomer unit. a computer search showed no notable sequence homology with other hemoproteins. it contains two histidine resid ... | 1989 | 2769763 |
| characterization of caedibacter endonucleobionts from the macronucleus of paramecium caudatum and the identification of a mutant with blocked r-body synthesis. | cytology, dna and host-symbiont relationships of x-like endosymbionts from paramecium caudatum are described. the symbionts (caedibacter caryophila, sp. nov.) live in the macronuclei of their hosts. they confer the killer trait upon their hosts and appear well adapted to their endonucleobiotic way of life. r bodies (proteinaceous ribbons associated with killing) are produced, but differ significantly from any of the four r-body classes previously described. c. caryophila and their r bodies were ... | 1988 | 3335230 |
| inhibition of paramecium caudatum by an alteromonas luteoviolacea antibiotic. | an antibiotic factor obtained from alteromonas luteoviolacea was shown to kill paramecium caudatum. this substance was shown to be destroyed by boiling, sonication, or freezing. it passed through a 0.45-micron-pore-size filter and was not precipitated from a culture supernatant with ethyl alcohol. its production varied with a. luteoviolacea strains and medium constituents. it was also shown to be distinct from the a. luteoviolacea antibiotic that affects bacterial cells. | 1986 | 3767343 |
| log-normal variation belts for growth curves. | prediction (confidence) or tolerance belts compound the uncertainty of sample estimates with the estimated extent of individual variation. the latter is therefore better described by variation belts, in which sample estimates are simply substituted for population parameters. variation belts can provide valuable graphical indications concerning the goodness of fit of postulated error models. while multiplicative least-squares (mls) methods appear appropriate in principle for biological growth, th ... | 1986 | 3814723 |
| isolation and characterization of macronuclei of paramecium caudatum infected with the macronucleus-specific bacterium holospora obtusa. | macronuclei from paramecium caudatum infected with holospora obtusa may be isolated on sucrose step gradients. macronuclei containing primarily infectious forms can be separated from those bearing predominantly reproductive forms. rna polymerase activity in infected macronuclei is greater by a factor of 5 than that in uninfected macronuclei. proteinase activity is also significantly higher. | 1985 | 3894389 |
| infection and maintenance of holospora obtusa, a macronucleus-specific bacterium of the ciliate paramecium caudatum. | the gram-negative bacterium holospora obtusa is a macronucleus-specific symbiont of the ciliate paramecium caudatum, which invades the host cell via a food vacuole, infects its macronucleus and grows exclusively in the nucleus. from infection experiments, we showed that a property of the macronucleus that is necessary for it to be recognized and infected by h. obtusa is commonly provided by p. caudatum, p. multimicronucleatum and 14 species of the p. aurelia complex, but not by p. jenningsi, p. ... | 1985 | 3905836 |
| x-ray microanalysis in cryosections of natively frozen paramecium caudatum with regard to ion distribution in ciliates. | cells of paramecium caudatum were shock-frozen without pretreatment for cryoultramicrotomy and freeze-dried for subsequent x-ray microanalysis. na, mg, p, s, cl, k, and ca were detected in different amounts in several subcellular compartments. in particular, calcium was localized below the cell surface (pellicle). trichocysts were found to contain significant amounts of na in their base but not in the tip. na, mg, p, s, cl, k, ca were found in electron dense deposits within the lumen of the cont ... | 1985 | 4001861 |
| [intensive disproportionate flow culture of paramecium caudatum]. | | 1973 | 4205167 |
| the photosensitizing action of carcinogens. i. the action of 2-naphthylamine on escherichia coli k-12 and paramecium caudatum. | | 1974 | 4595739 |
| [viability of the descendants of irradiated cells (experiments on paramecium caudatum and amoeba proteus)]. | | 1973 | 4728524 |
| interaction of blood sera with the culture of paramecium caudatum. ii. individual sensitivity to medium lethal x-ray doses determined by the consumption of complement by the culture of paramecium caudatum. | | 1966 | 4957705 |
| complement consumption by paramecium caudatum culture in normal fresh sera and its significance in the prognosis of radiation sickness in rats. | | 1968 | 5303817 |
| [serologic effectiveness of individual components of a culture of paramecium caudatum]. | | 1969 | 5792258 |
| infection of macronuclear anlagen of paramecium caudatum with the macronucleus-specific symbiont holospora obtusa. | the gram-negative bacterium holospora obtusa is an endonuclear symbiont of paramecium caudatum, which is incorporated into the host cells via the food vacuoles and infects their macronucleus exclusively, but never the micronucleus. since these two kinds of nuclei originate from a fertilization nucleus, it is assumed that the macronucleus acquires a property necessary for it to be recognized by the bacterium at a certain time during the nuclear differentiation process. we found that this property ... | 1983 | 6662855 |
| conjugation and meiosis of paramecium caudatum infected with the micronucleus-specific bacterium holospora elegans. | cells of two complementary mating types of paramecium caudatum, syngen 3, are infected with the micronucleus-specific bacterium holospora elegans. cells with bacteria in their micronuclei show the mating reaction with agglutination and pair formation. all the stages of meiosis in this species are observed and pronuclei are formed. during the pregamic divisions the bacteria are distributed to the division products, but many of the bacteria remain within the separation spindles, later being releas ... | 1983 | 6667699 |
| comparative studies on the photosensitizing potency of 5-methoxypsoralen and 8-methoxypsoralen as measured by cytolysis in paramecium caudatum and tetrahymena pyriformis, and growth inhibition and survival in candida albicans. | | 1982 | 6804993 |
| nonlysosomal vesicles (acidosomes) are involved in phagosome acidification in paramecium. | although acidification of phagocytic vacuoles has received a broadened interest with the development of ph-sensitive fluorescent probes to follow the ph changes of vacuoles and acidic vesicles in living cells, the mechanism responsible for the acidification of such vacuoles still remains in doubt. in previous studies of the digestive vacuole system in the ciliate paramecium caudatum we observed and described a unique population of apparently nonlysosomal vesicles that quickly fused with the newl ... | 1983 | 6885911 |
| the unique structures of protozoan myoglobin and yeast hemoglobin: an evolutionary diversity. | a hemoglobin-like protein is found in some of the single-celled organisms, but its structure is quite different from that of mammalian myoglobin or hemoglobin. for instance, a protozoan myoglobin isolated from paramecium caudatum consists of 116 amino acid residues, so that this contracted form is nearly two thirds of sperm whale myoglobin. yeast hemoglobin from candida norvegensis, on the other hand, is composed of a single polypeptide chain with 387 amino acid residues, but of two distinct dom ... | 1995 | 7584595 |
| monoclonal antibody to a bacterial endonuclear symbiont holospora cross reacts with proteins of contractile vacuole radial canals of paramecium species. | a monoclonal antibody (mab) ir-2-1 was raised against a 67-kda protein purified from the macronucleus-specific bacterial symbiont holospora obtusa of paramecium caudatum. the mab was found to react with two bands (31 and 67-kda) on gels of h. obtusa. indirect immunofluorescence microscopy showed that these antigens were distributed inside the cells. however, unexpectedly, this mab also cross reacted with the radial arms of the contractile vacuole in p. caudatum, p. tetraurelia, p. multimicronucl ... | 1994 | 7804254 |
| nuclear genes encoding chloroplast hemoglobins in the unicellular green alga chlamydomonas eugametos. | when the green unicellular alga chlamydomonas eugametos is grown under light/dark regimes, nuclear genes are periodically activated in response to the changes in light conditions. these genetic responses are dependent upon the activation of genes associated with photosynthesis (li616 and li637), nonphotosynthetic photoreceptors (li410 and li818) and the biological clock (li818). we report here that the li410 and li637 genes are part of a small gene family encoding hemoglobins (hbs) related to th ... | 1994 | 8177215 |
| occurrence of fragmented 16s rrna in an obligate bacterial endosymbiont of paramecium caudatum. | the phylogenetic position of caedibacter caryophila, a so far noncultured killer symbiont of paramecium caudatum, was elucidated by comparative sequence analysis of in vitro amplified 16s rrna genes (rdna). c. caryophila is a member of the alpha subclass of the proteobacteria phylum. within this subclass c. caryophila is moderately related to holospora obtusa, which is another obligate endosymbiont of paramecium caudatum, and to rickettsia. a 16s rrna targeted specific hybridization probe was de ... | 1993 | 8234331 |
| spectroscopical and functional characterization of the hemoglobin of nostoc commune (utex 584 (cyanobacterial). | structural analysis of a monomeric hemoglobin from the cyanobacterium nostoc commune strain utex 584, cyanoglobin (potts et al. (1992) science 256, 1690-1692), is presented. cyanoglobin binds molecular oxygen reversibly, with high oxygen affinity and non-cooperativity. there was no evidence for decreased stability of the pigment at 37 degrees c. cyanoglobin-specific antibodies showed no cross-reactivity with two reference hemoglobins, leghemoglobin a and sperm whale myoglobin. the absorption spe ... | 1996 | 8547335 |
| cloning and sequencing of gene coding for a periplasmic 5.4 kda peptide of the macronucleus-specific symbiont holospora obtusa of the ciliate paramecium caudatum. | we purified a 5.4 kda peptide which is present in the intermediate and infectious form, but not in the reproductive form of a symbiotic bacterium holospora obtusa of the ciliate paramecium caudatum. sequencing of its gene revealed that it encodes a peptide composed of 49 amino acids, and that the peptide is preceded by a putative signal peptide of 19 amino acids. we determined the transcription start point for the gene by primer extension analysis, indicating that the transcription starts with a ... | 1997 | 9200981 |
| graviresponses in paramecium caudatum and didinium nasutum examined under varied hypergravity conditions | the swimming behaviours of two species of ciliates characterized by different mechanosensory and ciliary motor properties were investigated under hypergravity up to 5.4 g. the experiments were designed to examine large numbers of cells using video recording, digital data processing and statistics for the documentation of the rates and orientations of swimming. the gravikinetic responses (change in active swimming rates) were calculated from (1) the velocities of vertical swimming in the gravity ... | 1994 | 9317786 |
| quantitative changes in periplasmic proteins of the macronucleus-specific bacterium holospora obtusa in the infection process of the ciliate paramecium caudatum. | the gram-negative bacterium holospora obtusa is a macronucleus-specific symbiont of the ciliate paramecium caudatum. the infectious form of this bacterium infects the host macronucleus through digestive vacuoles and differentiates into the reproductive form two days after the infection in the nucleus. the monoclonal antibodies if-3-1 and if-3-2 reacted with 39 and 15 kda periplasmic proteins, respectively, that were specific for the infectious form of h. obtusa. because the antigens were not det ... | 1997 | 9435135 |
| structure and expression of a groe-homologous operon of a macronucleus-specific symbiont holospora obtusa of the ciliate paramecium caudatum. | the reproductive form of a macronucleus-specific symbiont holospora obtusa, when harbored by the macronucleus of the ciliate paramecium caudatum, selectively synthesized a 63-kda protein which is immunologically related to groel, or hsp60, of escherichia coli. heat shock treatment of isolated cells of the reproductive and infectious form of the bacterium also induced the synthesis of the groel homolog. immunoblotting showed that the amount of this protein per cell, whether the reproductive or in ... | 1998 | 9495035 |
| effects of antibiotics on the early infection process of a macronuclear endosymbiotic bacterium holospora obtusa of paramecium caudatum. | we examined the effects of antibiotics involved in bacterial dna, rna and protein synthesis and host protein synthesis on the early infection process of the bacterium holospora obtusa, a macronucleus-specific symbiont of the ciliate paramecium caudatum. infection of the host macronucleus by the bacterium was not inhibited by mitomycin c, rifampicin and chloramphenicol. however, ingestion of the bacterium into the host digestive vacuoles and escape of the bacterium from the vacuoles to the host c ... | 1999 | 10518753 |
| [evolutionary relationship of rickettsia and eukaryotic mitochondria]. | to clarify the evolutionary relationship of rickettsiae and mitochondria, the conserved flat heat-shock protein hsp60 was phylogenetically studied in detail by using phylip and protml packages. the ample data set (50 species) included as many as possible representatives from the rickettsiaceae family, mitochondrial-type homologs from archezoa and mitochondrial homologs from protozoa. rickettsia prowazekii (that is the genus rickettsia) was shown to be the least diverging member within rickettsia ... | 2000 | 10765727 |
| aphidicolin inhibits dna replication in the micronucleus and blocks cytokinesis in paramecium caudatum. | aphidicolin, a selective inhibitor of dna polymerase, totally blocks dna replication in the micronucleus but not in the macronucleus of paramecium caudatum. the ciliates no longer divide and after 4 days the dna content of the macronucleus has increased by 64%. concomitantly the cell volume has increased by 53%. | 1999 | 10772760 |
| structural investigations of the hemoglobin of the cyanobacterium synechocystis pcc6803 reveal a unique distal heme pocket. | a putative hemoglobin (hb) gene, related to those previously characterized in the green alga chlamydomonas eugametos, the ciliated protozoan paramecium caudatum, the cyanobacterium nostoc commune and the bacterium mycobacterium tuberculosis, was recently discovered in the complete genome sequence of the cyanobacterium synechocystis pcc 6803. in this paper, we report the purification of synechocystis hb and describe some of its salient biochemical and spectroscopic properties. we show that the re ... | 2000 | 10903511 |
| notes on the zooplankton of a water body on the southern slope of mt babia góra (the carpathians). | the seepage of water on the gubernasówka clearing in the forest (alt. about 850 m) was investigated from the point of view of the occurrence of the paramecium aurelia species complex and other zooplanktonic organisms. though, none of the species of the complex was found, another morphological species of the paramecium genus, i.e. paramecium caudatum was registered. | 2000 | 11080919 |
| a primitive myoglobin from tetrahymena pyriformis: its heme environment, autoxidizability, and genomic dna structure. | a myoglobin-like protein isolated from tetrahymena pyriformis is composed of 121 amino acid residues. this is much smaller than sperm whale myoglobin by 32 residues, suggesting a distinct origin from the common globin gene. we have therefore examined this unique protein for its structural, spectral and stability properties. as a result, the rate of autoxidation of tetrahymena oxymyoglobin (mbo(2)) was found to be almost comparable to that of sperm whale mbo(2) over a wide range of ph 4-12 in 0.1 ... | 2000 | 11087949 |
| 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 |
| novel bacterial endosymbionts of acanthamoeba spp. related to the paramecium caudatum symbiont caedibacter caryophilus. | acanthamoebae are increasingly being recognized as hosts for obligate bacterial endosymbionts, most of which are presently uncharacterized. in this study, the phylogeny of three gram-negative, rod-shaped endosymbionts and their acanthamoeba host cells was analysed by the rrna approach. comparative analyses of 16s rdna sequences retrieved from amoebic cell lysates revealed that the endosymbionts of acanthamoeba polyphaga hn-3, acanthamoeba sp. uwc9 and acanthamoeba sp. uwe39 are related to the pa ... | 1999 | 11207753 |
| behavioural changes in paramecium and didinium exposed to short-term microgravity and hypergravity. | the swimming behaviour of two ciliate species, paramecium caudatum and didinium nasutum was analyzed under microgravity and hypergravity. in paramecium the differences between former upward and downward swimming rates disappeared under weightlessness. at microgravity the swimming rates equalled those of horizontally swimming cells at 1g. in contrast, the swimming rates of didinium increased under microgravity conditions, being larger than horizontal swimming rates at 1g. these findings are in ac ... | 1995 | 11542527 |
| catalase activity as a potential indicator of the reducer component of small closed ecosystems. | dynamics of catalase activity has been shown to reflect the growth curve of microorganisms in batch cultivation (celluloselythic bacteria bacillus acidocaldarius and bacteria of the associated microflora chlorella vulgaris). gas and substrate closure of the three component ecosystems with spatially separated components "producer-consumer-reducer" (chl. vulgaris-paramecium caudatum-b. acidocaldarius, two bacterial strains isolated from the associated microflora chl. vulgaris) demonstrated that th ... | 1997 | 11542574 |
| protozoan predation as a mechanism for the removal of cryptosporidium oocysts from wastewaters in constructed wetlands. | the removal of the protozoan parasite, cryptosporidium parvum, from wastewaters is becoming of increasing importance in the uk, especially since contamination of raw waters by sewage effluents has been implicated in major waterborne outbreaks of cryptosporidiosis in recent years. compared to conventional wastewater-treatment processes, constructed wetlands have demonstrated favourable removal rates for cryptosporidium oocysts. the removal mechanisms, however, remain unknown. predation by free-li ... | 2001 | 11804094 |
| the toxic symbiont caedibacter caryophila in the cytoplasm of paramecium novaurelia. | endosymbiotic bacteria were observed to inhabit the cytoplasm of the freshwater ciliate paramecium novaurelia. transmission electron microscopy and toxicity tests with sensitive paramecia showed that the endosymbionts belong to the genus caedibacter. the bacteria conferred a killer trait to their host paramecia. the production of a proteinaceous inclusion body ("r-body") in the bacterial cell makes them toxic to other paramecia after they become enclosed in food vacuoles. r-bodies of caedibacter ... | 2000 | 12035091 |
| [alternative pathways of the initial transformation of 2,4,6-trinitrotoluene by yeasts]. | a new model for the initial transformation of 2,4,6-trinitrotoluene (tnt) by facultatively anaerobic and aerobic yeasts is presented. the model is based on the data that saccharomyces sp. zs-a1 was able to reduce the nitrogroups of tnt with the formation of 2- and 4-hydroxyaminodinitrotoluenes (2-hadnt and 4-hadnt) as the major early tnt metabolites (the molar hadnt/tnt ratio reached 0.81), whereas aminodinitrotoluenes (adnts) and the hydride-meisenheimer complex of tnt (h-tnt) were the minor pr ... | 2002 | 12449631 |
| the genus caedibacter comprises endosymbionts of paramecium spp. related to the rickettsiales (alphaproteobacteria) and to francisella tularensis (gammaproteobacteria). | obligate bacterial endosymbionts of paramecia able to form refractile inclusion bodies (r bodies), thereby conferring a killer trait upon their ciliate hosts, have traditionally been grouped into the genus caedibacter: of the six species described to date, only the paramecium caudatum symbiont caedibacter caryophilus has been phylogenetically characterized by its 16s rrna gene sequence, and it was found to be a member of the alphaproteobacteria related to the rickettsiales: in this study, the ca ... | 2002 | 12450827 |
| [dna-containing polygonal structures detected in somatic nuclei of bursaria ovata during preparation to cryptobiosis]. | supramolecular chromatin organization of the somatic nucleus (macronucleus--ma) was studied in a free-living unicellular eukaryotic organism, the ciliate bursaria ovata beers 1952, at two late successive stages of its encystment (in the state of preparation to cryptobiosis). a modified miller's method (sergejeva et al., 1987) and the same technique in combination with high resolution dna autoradiography were used. in chromatin spread preparations of ma, not labeled by 3h-thymidine, numerous elec ... | 2002 | 12498081 |
| predation of cryptosporidium oocysts by protozoa and rotifers: implications for water quality and public health. | predation by free-living protozoa and rotifers was investigated as a possible mechanism for the removal of cryptosporidium parvum oocysts in aquatic ecosystems including wastewater treatment plants. free-living ciliated protozoa (stylonychia mytilus, paramecium caudatum and an unidentified wastewater wetland ciliate), an amoeba (acanthamoeba culbertsoni) and rotifers, all commonly found in aquatic ecosystems, were exposed to varying doses of c. parvum oocysts. all organisms investigated ingested ... | 2003 | 12639009 |
| phylogenetic relationships of non-mitochondrial nucleotide transport proteins in bacteria and eukaryotes. | current knowledge about the nucleotide metabolism of intracellular bacteria is very limited. here we report on the identification of nucleotide transport proteins (ntt) of two obligate endoparasites, caedibacter caryophila and holospora obtusa, both alpha-proteobacteria, which reside in the vegetative macronucleus of paramecium caudatum. for comparative studies, we also identified the first nucleotide transporter in chloroplasts of a red alga, i.e. galdieria sulphuraria, and further homologs in ... | 2003 | 12657464 |
| occurrence of articulins and epiplasmins in protists. | the cortex of ciliates. dinoflagellates, and euglenoids comprises a unique structure called the epiplasm, implicated in pattern-forming processes of the cell cortex and in maintaining cell shape. articulins, a novel class of cytoskeletal proteins, are major constituents of the epiplasm in the flagellate euglena gracilis and the ciliate pseudomicrothorax dubius. the hallmark of articulins is a core domain of repetitive motifs of alternating valine and proline residues, the vpv-motif. the vpv-moti ... | 2003 | 12674475 |
| host growth conditions regulate the plasticity of horizontal and vertical transmission in holospora undulata, a bacterial parasite of the protozoan paramecium caudatum. | a parasite might be prohibited from investing simultaneously in horizontal (infection of new hosts) and vertical (infection of the current host's offspring) transmission because of developmental, physiological, or evolutionary costs and constraints. rather, these constraints may select for adaptive phenotypic plasticity, where the parasite uses the transmission pathway that maximizes transmission in the current ecological and epidemiological conditions. by varying environmental conditions for th ... | 2003 | 12940358 |
| biodiversity of algae and protozoa in a natural waste stabilization pond: a field study. | a field study was carried out on the biodiversity of protozoa and algae from a natural waste stabilization pond during november, 1996 to april, 1997. the raw waste and pond samples were analysed for physico-chemical and biological parameters. high dissolved oxygen (do) coinciding with phytoplankton peak was recorded. the algae--chlorella vulgaris, scenedesmus acuminatus, oscillatoria brevis and nostoc piscinale and protozoa--paramecium caudatum, acanthamoeba sp., bodo saltans and oikomonas termo ... | 2003 | 12974463 |
| [effect of polyethylene-glycol on paramecium caudatum and trichomonas vaginalis in experiments in vitro]. | | 1956 | 13419369 |
| [observations on the desoxyribonucleic acid content of nuclear apparatus of ciliata: paramecium caudatum ehr]. | | 1962 | 13869789 |
| retardation of division of three ciliates by intermittent and continuous ultraviolet radiations at different temperatures. | the same dosage of ultraviolet (uv) radiation retards division of several protozoans more effectively when the light is intermittent than when it is continuous, and especially at temperatures of 25-35 degrees c. at lower temperatures the difference between the effects of intermittent and continuous radiations is less marked. somewhat similar results were obtained with the ciliates paramecium caudatum, blepharisma japonicum, and colpidium colpoda, the disparity between intermittent and continuous ... | 1963 | 13947762 |
| [resistance to lethal roentgen irradiations by the interaction of blood sera with a culture of paramecium caudatum]. | | 1964 | 14172087 |
| interaction of the blood sera with paramecium caudatum cultures. i. complement consumption by paramecium cultures in normal fresh sera. | | 1964 | 14270176 |
| poison susceptibility of ciliates (paramecium caudatum ehrbg. stylonychia mytilus ehrbg.), adapted to the hypertonic medium. | | 1961 | 14494342 |
| dna replication and transcription in new macronuclei of paramecium caudatum exconjugants. | we analyzed the onset and location of replicational and transcriptional activity during the first cell cycle in new macronuclei of the ciliate paramecium caudatum exconjugants. synchronous exconjugants were pulse labeled with 5-bromo-2'-deoxyuridine or 5-bromouridine-5'-triphosphate to visualize replication or transcription sites, respectively. the first morphological change after macronuclear determination is the appearance of heterochromatic aggregates. confocal microscopic examination reveale ... | 2003 | 14712864 |
| heme-ligand tunneling in group i truncated hemoglobins. | truncated hemoglobins (trhbs) are small hemoproteins forming a separate cluster within the hemoglobin superfamily; their functional roles in bacteria, plants, and unicellular eukaryotes are marginally understood. crystallographic investigations have shown that the trhb fold (a two-on-two alpha-helical sandwich related to the globin fold) hosts a protein matrix tunnel system offering a potential path for ligand diffusion to the heme distal site. the tunnel topology is conserved in group i trhbs, ... | 2004 | 15016811 |
| [a comparative analysis of stachybotrys chartarum strains isolated in russia]. | this work deals with a comparative analysis of stachybotrys chartarum strains isolated from various artificial cellulose-containing materials and natural substrates in the geographically distant regions of russia. the analysis included the determination of the spore size, the strain toxicity to paramecium caudatum, the strain resistance to the fungicides benomil, olilen, and tilt, and the pcr study of the genome structure with the aid of a primer that was complementary to the core sequence of th ... | 2004 | 15074044 |
| the endosymbiotic bacterium holospora obtusa enhances heat-shock gene expression of the host paramecium caudatum. | 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 degrees c to 35 degrees 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 f ... | 2003 | 15132173 |
| [dynamics of structural changes of paramecium caudatum and bursaria truncatella macronuclear chromatin and nucleoli under hypotonic conditions]. | dynamics of structural changes of nucleoli, complex nucleolar aggregates and chromatin bodies in macronuclei (ma) of ciliates paramecium candatum and bursaria truncatella under hypotonic conditions was studied. it was shown that after a 3 min hypotonic treatment nuclei swelled and became highly vacuolated. 3d-reconstruction showed that such nucleoli were formed by nucleolonema-like threads about 100-200 nm in thickness. intranucleolar chromatin bodies decompacted, but remained bound with fibrill ... | 2004 | 15344892 |
| co-infection of the macronucleus of paramecium caudatum by free-living bacteria together with the infectious holospora obtusa. | infection experiments were performed incubating paramecium caudatum with non-infectious free-living bacteria or weakly infectious intracellular bacteria together with the infectious holospora obtusa. two of four non-infectious free-living bacteria (enterobacter aerogenes and klebsiella pneumoniae) were found to get into the nuclei when added to paramecium together with h. obtusa. the endonuclear bacterium nonospora macronucleata that is weakly infectious by itself increases its infectivity when ... | 2004 | 15352323 |
| differences in gene expression of the ciliate paramecium caudatum caused by endonuclear symbiosis with holospora obtusa, revealed using differential display reverse transcribed pcr. | we identified six genes of paramecium caudatum, which differentially expressed in holospora obtusa-bearing and h. obtusa-free cells using differential display reverse transcribed pcr (ddrt-pcr). northern blot analyses revealed that two of the genes, ca10-3 and ca20-2, were expressed extensively in the h. obtusa-free cell, while the other four, as16-1, cs14, cs21 and ca17-1, were expressed more in the h. obtusa-bearing cell. putative amino acid sequences of ca10-3, as16-1 and ca17-1 showed high h ... | 2004 | 15522509 |
| paramecium caudatum acquires heat-shock resistance in ciliary movement by infection with the endonuclear symbiotic bacterium holospora obtusa. | holospora obtusa is a macronucleus-specific bacterium of the ciliate paramecium caudatum. three types of p. caudatum cells (h. obtusa-free cells, cells bearing the reproductive form of h. obtusa and cells bearing the predominantly infectious form of h. obtusa) cultured at 25 degrees c were transferred to 4, 10, 25, 35 and 40 degrees c and their swimming velocities were measured by taking photomicrographs with two-second exposures. the h. obtusa-free cells almost ceased swimming at both 4 and 40 ... | 2005 | 15668007 |
| [migration of n-alkanes from diesel oil along the bacteria-ciliates trophic chain]. | the data on the dynamics of the content and qualitative composition of intracellular alkanes in paramecium caudatum ehrenberg, 1838 cells feeding on bacteria with different levels of exposure to diesel oil are presented. the possibility of migration of alkanes from diesel oil along the trophic chain from bacteria to ciliates was demonstrated. | 2005 | 16004271 |
| [dynamics of the reversible transition of vibrio cholerae into the uncultivable state in the presence of organic and inorganic microcosmic components]. | the dynamics of the transition of v. cholerae into the uncultivable state in distilled, river and tap water, containing organic and inorganic components added, was studied. as additives, potassium nitrate, potassium phosphate, magnesium sulfate, ammonium chloride, lysine, alpha-ketoglutarate, succinic acid, catalase were used. the study of the influence of biotic factors on transition into the uncultivable state was carried out in the presence of one-celled green algae scenedesmus quadricauda or ... | 2005 | 16146223 |
| distinct localization of a beta-tubulin epitope in the tetrahymena thermophila and paramecium caudatum cortex. | many of the highly organized microtubular arrangements in ciliates are located in the cortical area containing membrane vesicles and vacuoles. in tetrahymena thermophila and paramecium caudatum, immunofluorescence microscopy with the monoclonal antibody tu-06, directed against beta-tubulin, revealed distinct staining of this cortical region alone, while the cilia and other microtubular structures were unstained. the specificity of the antibody was confirmed by immunoblotting and by preabsorption ... | 2005 | 16228897 |
| translocation of an 89-kda periplasmic protein is associated with holospora infection. | the symbiotic bacterium holospora obtusa infects the macronucleus of the ciliate paramecium caudatum. after ingestion by its host, an infectious form of holospora with an electron-translucent tip passes through the host digestive vacuole and penetrates the macronuclear envelope with this tip. to investigate the underlying molecular mechanism of this process, we raised a monoclonal antibody against the tip-specific 89-kda protein, sequenced this partially, and identified the corresponding complet ... | 2005 | 16236256 |
| [use of infusoria paramecium caudatum for the evaluation of the toxicity of antigens of different causative quarantine agents]. | the results of the evaluation of the toxicity of bacterial antigens obtained from the causative agents of plaque, glanders, melioidosis, cholera on infusoria of the species p. caudatum, as well as on cell lines l-929, cho k-1 and peritoneal macrophages of balb/c mice, are presented. as revealed in this study, the method of toxicity determination on infusoria is similar in its sensitivity to the methods of testing on. cho k-1 and l-929 cells, but the former is simpler, more available and permits ... | 2005 | 16279542 |
| nocodazole inhibits macronuclear infection with holospora obtusa in paramecium caudatum. | holospora obtusa is a gram-negative bacterium inhabiting the macronucleus of the ciliate paramecium caudatum. experimental infection with h. obtusa was carried out under nocodazole treatment. nocodazole has been shown to cause disassembly of the cytoplasmic microtubules radiating from the cytopharynx and postoral fibers in p. caudatum. treatment with this drug did not prevent the ingestion of both prey bacteria and h. obtusa, but it reduced the phagosome number and affected cyclosis. in situ hyb ... | 2005 | 16333573 |
| cryopreservation of holospora undulata, a bacterial parasite of the ciliate paramecium caudatum. | we investigated cryopreservation of horizontal transmission stages of holospora undulata, a micronucleus-specific bacterial parasite of paramecium caudatum. unlike in previous studies on related holospora species, protocols using glycerol as cryoprotectant failed entirely. in contrast, freezing with dimethyl sulfoxide (me2so) conserved infectiousness of nearly all replicate inocula, although infection success was considerably lower than that of fresh inocula. infection probability was enhanced b ... | 2006 | 16426600 |
| 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 |
| temperature-dependent transmission and latency of holospora undulata, a micronucleus-specific parasite of the ciliate paramecium caudatum. | transmission of parasites to new hosts crucially depends on the timing of production of transmission stages and their capacity to start an infection. these parameters may be influenced by genetic factors, but also by the environment. we tested the effects of temperature and host genotype on infection probability and latency in experimental populations of the ciliate paramecium caudatum, after exposure to infectious forms of its bacterial parasite holospora undulata. temperature had a significant ... | 2006 | 16627290 |
| experimental evolution of resistance in paramecium caudatum against the bacterial parasite holospora undulata. | host-parasite coevolution is often described as a process of reciprocal adaptation and counter adaptation, driven by frequency-dependent selection. this requires that different parasite genotypes perform differently on different host genotypes. such genotype-by-genotype interactions arise if adaptation to one host (or parasite) genotype reduces performance on others. these direct costs of adaptation can maintain genetic polymorphism and generate geographic patterns of local host or parasite adap ... | 2006 | 16892968 |
| isolation and characterization of a paramecium cdna clone encoding a putative serine/threonine protein kinase. | mitogen-activated protein (map) kinases, a closely related family of protein kinases, are involved in cell cycle regulation and differentiation in yeast and human cells. they have not been documented in ciliates. we used pcr to amplify dna sequences of a ciliated protozoan--paramecium caudatum--using primers corresponding to amino acid sequences that are common to map kinases. we isolated and sequenced one putative map kinase-like serine/threonine kinase cdna from p. caudatum. this cdna, called ... | 2007 | 17375362 |
| direct and correlated responses to selection in a host-parasite system: testing for the emergence of genotype specificity. | genotype x environment interactions can facilitate coexistence of locally adapted specialists. interactions evolve if adaptation to one environment trades off with performance in others. we investigated whether evolution on one host genotype traded off with performance on others in long-term experimental populations of different genotypes of the protozoan paramecium caudatum, infected with the bacterial parasite holospora undulata. a total of nine parasite selection lines evolving on three host ... | 2007 | 17683424 |
| fate of the 63-kda periplasmic protein of the infectious form of the endonuclear symbiotic bacterium holospora obtusa during the infection process. | holospora obtusa is a macronucleus-specific endosymbiotic bacterium of the ciliate paramecium caudatum. we report the secretion of a 63-kda periplasmic protein of an infectious form of the bacterium into the macronucleus of its host. indirect immunofluorescence microscopy with five monoclonal antibodies against the 63-kda protein demonstrated that, soon after the bacterial invasion into the host macronucleus, the protein was detected in the infected macronucleus and that levels of the protein in ... | 2008 | 18179589 |
| identification of ligand-binding pathways in truncated hemoglobins using locally enhanced sampling molecular dynamics. | this chapter reviews the use of a locally enhanced sampling molecular dynamics (lesmd) for the study of ligand binding in truncated hemoglobins. the method, however, can be applied to any protein-ligand system. truncated hemoglobins appear to have a tunnel(s) potentially used by the ligand to bind. these structural features give some indication of how the ligand moves through the protein to bind but do not give the complete picture. the lesmd method has been used to investigate the pathways of l ... | 2008 | 18433642 |
| effects of perfluorooctane sulfonate (pfos) on swimming behavior and membrane potential of paramecium caudatum. | persistent perfluorinated organic compounds such as perfluorooctane sulfonate (pfos) and perfluorooctanoic acid (pfoa) were distributed widely in the global. pfos (15 microm or higher) caused backward swimming of paramecia. the triton-extracted paramecia, where the membrane was disrupted and the externally applied chemicals are freely accessible to the ciliary apparatus, showed forward swimming up to 0.1 microm ca2+ in the medium and backward swimming at about 0.2 microm and higher. pfos (0.1 mm ... | 2008 | 18544907 |
| ecological and genetic determinants of multiple infection and aggregation in a microbial host-parasite system. | the number of parasites colonizing a host (termed 'multiple infection') is an important determinant of host-parasite interactions. in theory, multiple infection is determined by random mass action in genetically and spatially homogeneous populations of host and parasite. in real populations, deviations from these assumptions may strongly influence levels of multiple infection. we carried out inoculation experiments in microcosms of the freshwater protozoan paramecium caudatum and its bacterial p ... | 2008 | 18775095 |
| micronucleus-specific bacterium holospora elegans irreversibly enhances stress gene expression of the host paramecium caudatum. | 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 ... | 2008 | 19120797 |
| 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 ... | 2009 | 19231281 |
| 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 ... | 2009 | 19320981 |
| 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 |
| 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 ... | 2009 | 19447509 |
| methods for the pure culture of certain protozoa. | some media are described which inhibit bacterial growth, but are favorable to protozoan development. a purification technique, which takes advantage of geotropic responses, was devised and used successfully with 7 species of protozoa, including flagellates and ciliates. the method was also used with a spirillum. for one flagellate which could not be purified in this manner, a procedure involving chemical sterilization was employed. paramecium caudatum was purified, but failed to develop subseque ... | 1930 | 19869728 |
| 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 ... | 2010 | 20163449 |
| 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 ... | 2010 | 20406349 |
| 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 ... | 2010 | 20722731 |