| 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 |
| [effect of actinomycin d on salinity acclimation of paramecium calkinsi (ciliophora, peniculia)]. | salinity acclimation of euryhaline ciliate paramecium calkinsi evaluated by swimming velocity was over in 4-5 days. in two series of the main experiment, the acclimation was over in two and three days when actinomycin d (an inhibitor of dna-dependent rna polymerase) was added after various periods of the ciliate incubation at a changed salinity (0, 3, 6, and 24 h). the obtained data indicate that the inhibiting effect of actinomycin d on salinity acclimation of p. calkinsi is manifested only wit ... | 2004 | 15049064 |
| a two-locus molecular characterization of paramecium calkinsi. | paramecium calkinsi (ciliophora, protozoa) is a euryhaline species which was first identified in freshwater habitats, but subsequently several strains were also collected from brackish water. it is characterized by clockwise spiral swimming movement and the general morphology of the "bursaria type." the present paper is the first molecular characterization of p. calkinsi strains recently collected in distant regions in russia using its1-5.8s- its2-5'lsu rdna (1100bp) and coi (620bp) mtdna sequen ... | 2011 | 21798802 |
| bacterial endocytobionts of the ciliate paramecium calkinsi. | five species of gram-negative bacteria inhabiting the cytoplasm and the macronucleus of the ciliate paramecium calkinsi are described. two species of endocytobionts have been found in the cytoplasm. both of them were represented by only a vegetative form. in the case of the first species, numerous endocytobiotic bacteria (length, 2 μm; diameter, 0.3-0.4 μm) were enclosed in individual endobiontophoral vacuoles. the second one was not as abundant in its host cells and the bacteria lie freely in t ... | 1993 | 23195737 |
| host and symbiont intraspecific variability: the case of paramecium calkinsi and "candidatus trichorickettsia mobilis". | newly isolated strains of the ciliate paramecium calkinsi and their cytoplasmic bacterial endosymbionts were characterized by a multidisciplinary approach, including live observation, ultrastructural investigation, and molecular analysis. despite morphological resemblance, the characterized p. calkinsi strains showed a significant molecular divergence compared to conspecifics, possibly hinting for a cryptic speciation. the endosymbionts were clearly found to be affiliated to the species "candida ... | 2017 | 29287245 |
| toxic effects of antimalarial drugs in paramecium: role of calcium channels. | the antimalarial drugs, quinacrine, quinine and mefloquine, as well as the structurally-similar compound, w-7, inhibit calcium-dependent backward swimming and calcium currents in paramecium calkinsi. these drugs are also toxic to paramecia at high concentrations. therefore, one site of toxic action of the drugs may be the calcium channel. to test this hypothesis, the toxicity of the antimalarials and w-7 was compared in paramecia with and without calcium channels. since calcium channels are loca ... | 1997 | 9163925 |
| pharmacological prevention of acute lead poisoning in paramecium. | to understand how lead (pb2+) and other metals and chelating agents effect living cells, behavioral experiments in the marine ciliate paramecium calkinsi were carried out. the duration of backward swimming behavior (bsb) of paramecium was partially reduced when cells were exposed to 100 microm of ni2+, cd2+ and co2+. in contrast, pb2+ increased paramecium bsb in a dose-dependent manner. thus, 1, 10, 20, 50 and 100 microm of pb2+ increased the duration of bsb by 20.4, 83.9, 143.2, 163.2 and 185.2 ... | 1996 | 8658535 |
| aminotransferase and the production of alanine during hyperosmotic stress in paramecium calkinsi. | when paramecium calkinsi encounter hyperosmotic stress, intracellular free alanine increases. in vivo assays indicate that the reaction catalyzed by alanine aminotransferase contributes to the build up of alanine in response to hyperosmotic shock. 14c-pyruvate is converted to 14c-alanine in cells grown axenically at 200 mosm. when shifted to 600 mosm, the rate of conversion of pyruvate to alanine increases, and conversion at either 200 or 600 mosm is blocked by 1 mm aminooxyacetic acid (aoa), an ... | 2013 | 8292998 |
| antimalarial drugs inhibit calcium-dependent backward swimming and calcium currents in paramecium calkinsi. | the antimalarial drugs, quinacrine, chloroquine, quinine, primaquine, and mefloquine, share structural similarities with w-7, a compound that inhibits calcium-dependent backward swimming and calcium currents in paramecium. therefore, we tested whether antimalarial drugs also inhibit backward swimming and calcium currents in p. calkinsi. when the paramecium is depolarized in high potassium medium, voltage-dependent calcium channels in the ciliary membrane open causing the cell to swim backward fo ... | 1993 | 8315608 |
| guanine nucleotides modulate calcium currents in a marine paramecium. | voltage-dependent calcium channels play a critical role in many cell functions and in many cell types ranging from protozoa to vertebrates. we have shown previously that guanine nucleotides modulate the calcium action potential and the duration of backward swimming in paramecium, both indirect measurements of calcium channel function. to determine whether guanine nucleotides to indeed alter calcium currents, the inward calcium current (ica) in paramecium calkinsi was studied. first, the calcium ... | 1993 | 8386740 |
| the response of contractile and non-contractile vacuoles of paramecium calkinsi to widely varying salinities. | paramecium calkinsi from tidal marshes survive a wide salinity range. fluid output of contractile vacuoles of these cells decreased as salinity of the medium to which they were acclimated increased, and both pulse rate and vacuole volume were used to regulate output. when cells were first exposed to more dilute medium, contractile vacuoles greatly increased volume so that fluid output increased even though pulse rate decreased. in cells shifted to a more concentrated medium, contractile vacuole ... | 2007 | 1818200 |
| gtp-gamma-s increases the duration of backward swimming behavior and the calcium action potential in marine paramecium. | behavioral and electrophysiological experiments were made to examine the hypothesis that g-proteins modulate the voltage-dependent calcium channel in the marine ciliate paramecium calkinsi. it was found that guanosine-5'-o-(3-thiotriphosphate) (gtp-gamma-s), an analogue of gtp that binds to and activates g-proteins, increased the duration of backward swimming behavior in reversibly permeabilized paramecium in an irreversible and concentration-dependent manner. at 1 mumol l-1 gtp-gamma-s, the dur ... | 1991 | 1849956 |
| free amino acids and cell volume regulation in the euryhaline ciliate paramecium calkinsi. | paramecium calkinsi was isolated from a tidal marsh in which the salinity fluctuated widely on a daily basis. in the laboratory, this ciliate survived for days in sea water ranging in osmotic strength from 10 to 2,000 mosm and divided in nutritive media of 1,000 mosm or less. when transferred from 750 to 250 mosm, cells swelled but regained 78% of the original volume within 60 min and the original volume within 1 day. cells acclimated to 250 mosm and transferred to 750 mosm shrank, regained 40% ... | 1989 | 2769205 |
| the occurrence of a new variety containing two opposite mating types of paramecium calkinsi as found in sea water of high salinity content. | | 1950 | 14791542 |
| extraction of a mating reaction inhibiting agent from paramecium calkinsi. | | 1950 | 16578337 |
| mating types and conjugation of four different races of paramecium calkinsi and the effect of x-rays on the mating reaction. | | 1948 | 18933453 |
| induction of autogamy in single animals of paramecium calkinsi following mixture of two mating types. | | 1948 | 18887875 |
| the occurrence of conjugation in paramecium calkinsi. | | 1928 | 17735165 |