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1

Pharmacological attenuation of Paramecium fluid-phase endocytosis

100%
Wiejak J., Surmacz L., Wyroba B.
Folia Biologica
|
2007
|
vol. 55
|
issue 3-4
95-100
EN
Spectrophotometric quantification of fluid phase endocytosis in the presence of different pharmacological compounds was performed in the model unicellular eukaryote Paramecium. The kinetics of Lucifer Yellow Carbohydrazide (LY) uptake in cells exposed to forskolin and isoproterenol ? known to stimulate phagocytosis in this cell ? was analyzed. Reduction in both the rate of endocytosis and total accumulation of fluid phase marker was observed following the treatment. Forskolin diminished total LY accumulation by 11% and 21% after 5 min and 25 min of incubation, respectively, whereas the rate of uptake was lowered by 21% in comparison to control cells. The inhibitory effect of isoproterenol was less pronounced than that of forskolin. The total accumulation of LY was decreased by 11% in 5 min as compared to the untreated cells and this effect was persistent upon further exposition to this reagent up to 25 min. To better understand these observations, the effect of inhibitors of PKA and cAMP phosphodiesterase on fluid phase uptake was tested. 3-isobutyl-1-methyl xanthine (IBMX) caused 12% decrease in LY accumulation after 5 min of incubation. In combination with isoproterenol or forskolin, IBMX enhanced their inhibitory effect on fluid endocytosis, which was lowered by 25% and 29%, respectively. The strongest inhibitory effect on fluid endocytosis was exerted by the 10 _M PKA inhibitor, which diminished endocytosis by 35% in 5 min. These results suggest that Paramecium fluid phase uptake may be regulated through activation of PKA, although the precise mechanism of this process has not yet been elucidated.
2

Further studies on the Paramecium sp. in the Eastern Carpathians in Ukraine

100%
Przybos E.
Folia Biologica
|
1995
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vol. 43
|
issue 1-2
9-14
EN
In the samples collected from the water bodies situated on the territory of the recently studied regions of the Eastern Carpathians in Ukraine no Paramecia belonging to the Paramecium aurelia species complex were found.Only the presence of the related taxonomic species Paramecium caudatum and Paramecium multimicronucleatum was recorded.The studied water bodies were oligotrophic and the composition of planktonic organisms in them was rather poor.The crucial factor which affecting the plankton composition may be the water chemistry, determined by the subsrtatum, and considerably dependent also on the season of sampling.
3

Toxicity of fastac 10 EC, a pyrethroid insecticide, to Paramecium primaurelia and Tubifex sp.

100%
Komala Z.
Folia Biologica
|
1992
|
vol. 40
|
issue 3-4
109-112
EN
The pyrethroide,Fastac 10 EC was tested on the paramecia and Tubifex sp. The results showed that both tests are valid for estimation of the toxicity of the pesticide. However, the Paramecium test is more sensitive when one is investigating the direct toxicity of the compound. The great validity of the Tubifex test lies in the possibility of tracing the teratogenic effects of the pesticides.
4

The effect of isathrine 10 EC, a pyrethroid insecticide, on Paramecium primaurelia. Preliminary report

100%
Komala Z.
Folia Biologica
|
1992
|
vol. 40
|
issue 1-2
53-55
EN
Dilutions of Isathrine 10 EC containing in 100 cm3 of water up to 1.25 mg of bioresmethrin were toxic to paramecia, causing 100% mortality immediately or within a few seconds of treatment. In a dilution containing 0.625 mg% of bioresmethrin the mean number of surviving paramecia was 8 after 24 hours' treatment. Lower concentrations posed no threat to paramecia.
5

Molecular phylogenetics of representative Paramecium species

88%
Maciejewska A.
Folia Biologica
|
2007
|
vol. 55
|
issue 1-2
1-8
EN
The genus Paramecium has been known to science for 250 years and contains some of the most widely studied species of ciliates. At present, the basic research object for phylogenetic studies is the genome of various paramecia. One of the most widely used markers are genes coding for various rRNA's. Comparative analyses of sequences coding rRNA were applied for resolving the systematic position of some paramecia species and also for the establishment of an accurate taxonomy of Paramecium. Paramecia were also model organisms for their systematic group in more general studies in a comparative analysis among ciliates, fungi, plants and multicellular animals, illustrating the evolutionary relationships between Archaebacteria and Eucaryota. A new, revolutionary genealogy proposed the shifting of presumptively advanced groups towards more primitive ones, and traditionally primitive forms were located closer to highly specialized taxa, but rRNA analysis did not unambiguously resolve associations within the studied groups. Because of the aforementioned concerns, the number of molecular markers used for alternative studies is growing, such as genes coding proteins from the Hsp family or histone proteins. Other promising candidate markers may be hemoglobin genes or genes coding ?-tubulins. In case of comparative analyses of nucleotide sequences, the outcome of the research usually depends upon a subjective choice of DNA. One of the directions of research in molecular phylogenetics include indirect methods that allow for an estimation of entire genomes, for example RAPD-PCR-fingerprinting.
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