Tetrahymena pyriformis

/Tag:Tetrahymena pyriformis

The Effects of Two New Amphetamine-like Derivatives on the Phagocytic Ability of the Protozoan, Tetrahymena pyriformis

Giorgos Alevisopoulos, Maria Stefanidou, Margarita Pagou, Theodora Siatra-Papastaikoudi and Antonios Koutselinis

Six new amphetamine-like molecules (2-[2,3-dihydro-4H-1,4-benzoxazine-4-yl]-1-methyl-2-[1-methyl-2-phenylethylamino] ethanamines) were synthesised and their physicochemical behaviour was studied. The log P values (index of lipophilicity) of the derivatives were calculated according to Rekker’s fragmental system. One derivative representative of each series (C-5508 and C-5512) was selected, and their biological effects on the phagocytic ability of the protozoan, Tetrahymena pyriformis, were studied as a basic functional test for an amphetamine-like action. Furthermore, the action of both derivatives when administered concomitantly with haloperidol was also investigated. The data indicate that both derivatives significantly increased the phagocytic ability of the protozoan (p < 0.001), presumably via an alternative pathway to that of one of the dopamine monoaminergic pools. The administration of haloperidol significantly suppressed phagocytosis (p < 0.001). However, cultures exposed to the derivatives and to haloperidol indicated quantitatively different reactions. The lipophilic behaviours of the derivatives provide a possible explanation for such distinct effects.[/fusion_toggle] [/fusion_builder_column][fusion_builder_column row_column_index="1_2" type="1_1" background_position="left top" background_color="" border_size="" border_color="" border_style="solid" spacing="yes" background_image="" background_repeat="no-repeat" padding="" margin_top="0px" margin_bottom="0px" class="" id="" animation_type="" animation_speed="0.3" animation_direction="left" hide_on_mobile="no" center_content="no" min_height="none"][s2If current_user_cannot(access_s2member_level0)] You need to register (for free) to download this article. Please log in/register here.[/s2If]

Comparative Quantitative Structure–Activity–Activity Relationships for Toxicity to Tetrahymena pyriformis and Pimephales promelas

Iiris Kahn, Uko Maran, Emilio Benfenati, Tatiana I. Netzeva, T. Wayne Schultz and Mark T.D. Cronin

An approach for predicting acute aquatic toxicity, in the form of a quantitative structure–activity–activity relationship (QSAAR), is described. This study assessed relative toxic effects to a fish, Pimephales promelas, and a ciliate, Tetrahymena pyriformis, and attempted to form relationships between them. A good agreement between toxic potencies (R2 = 0.754) was found for a chemically diverse dataset of 364 compounds, when using toxicity to the ciliate as a surrogate to that for fish. This relationship was extended by adding three theoretical structural descriptors of the molecules. The inclusion of these descriptors improved the relationship further (R2 = 0.824). The structural features that were found to improve the extrapolation between the toxicity to the two different species were related to the electron distribution of the carbon skeleton of the toxicant, its hydrogen-bonding ability, and its relative nitrogen content. Such a QSAAR approach provides a potential tool for predicting the toxicities of chemicals for environmental risk assessment and thus for reducing animal tests.
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The Tubifex tubifex Assay for the Determination of Acute Toxicity

Milonv Tichý, Marián Rucki, Iveta Hanzlíková and Zdenevk Roth

An express (3-minute) test for acute toxicity determination by using the oligochaete annelid, Tubifex tubifex, is described. The EC50(Tubifex tubifex) [EC50(Tt)] for movement inhibition was calculated by using a concentration–response dependence. The reproducibility of the test was checked over several years and by several workers. Its applicability is limited to compounds which are soluble in water. The calculated EC50(Tt) indices correlate with LC50 values determined by using the fish, Pimephales promelas (96- hour assay), and with ICG50 values determined by using the ciliate, Tetrahymena pyriformis (48-hour assay) with high statistical significance (r = 0.822, n = 35, and r = 0.927, n = 80, respectively). The correlation between the EC50(Tt) indices and rat oral LD50 values (48-hour assay) was r = 0.519 (n = 67). The correlation within organic compounds was closer (r = 0.635, n = 60) than with the heterogeneous series of chemicals. A similar trend was noticed for the correlation with mouse oral LD50 values (r = 0.479, n = 56) with the heterogeneous series of chemicals, as compared that with the series without inorganic salts (r = 0.605, n = 42), and similarly with mouse intraperitoneal LD50 values, where r = 0.543 (n = 50) with the heterogeneous series of chemicals and r = 0.893 (n = 33) with the series of organic chemicals.
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