Thermophila BF5 Research Articles

Toxic effects of vinca alkaloids from Catharanthus roseus (L.) G. Don on Tetrahymena thermophila BF5 growth by microcalorimetry

Vinca alkaloids (VAs) obtained from Catharanthus roseus (L.) G. Don have been employed in clinic owing to their antitumor effects. Toxicities of VAs are significantly different despite similar structures. However, the structure-toxicity relationships of VAs remain unclear. In view of this, Tetrahymena thermophila BF5 (T.t. BF5) was used to evaluate the toxic effects of VAs by microcalorimetry, which could dynamically monitor the growth of T.t. BF5. The IC10 results showed the relative toxicity of VAs was vincristine (105.0±6.3μgmL−1)>vindesine (135.1±5.1μgmL−1)>vinblastine (215.5±4.7μgmL−1)>vinorelbine (314.2±5.9μgmL−1). Analysis of structure-toxicity relationships indicated that acylamide at C3 position and hydroxyl at C4 position might contribute to more toxicity. A long conjugation effect appearing in VAs could increase the toxicity when the N1 position was substituted with formyl group.

Isothermal microcalorimetric investigation of the toxic action of the effective constituents of Podophyllum emodi Wall on Tetrahymena thermophila BF5

The effects of podophyllotoxin (PPT), etoposide (VP16), and teniposide (VM26) on the growth of Tetrahymena thermophila BF5 (T.t.BF5) was investigated by the TAM AIR isothermal microcalorimetric system. The extent and duration of toxic effects on T.t.BF5 metabolism were evaluated by studying the growth rate constant (k), inhibitory ratio (I), maximum heat-output power (Pmax), peak time of maximum heat-output power (tp), and total heat production (Qt). Experimental results showed that the value of tp increased and the value of k and Pmax decreased with the increasing compound concentrations. Furthermore, the growth rate constant k was linear with compound concentration. The corresponding I was obtained from different k values. According to the IC10 (the concentration of inhibitor when the inhibitory ratio is 10 %), the relative toxicity of the three compounds was PPT (IC10 = 49.6 μg mL−1) > VP16 (IC10 = 117.5 μg mL−1) > VM26 (IC10 = 359.1 μg mL−1). The preliminary investigation of structure–activity relationships showed that the thienyl group was likely responsible for reducing the toxicity of the compounds.

Evaluate the potential environmental toxicity of quantum dots on ciliated protozoa by microcalorimetry

In the present study, we evaluated the toxic effects of mercaptoacetic acid (MAA)-capped CdSe QDs and CdSe/ZnS QDs to particle-ingesting model ciliated protozoa Tetrahymena thermophila BF5 (T. thermophila BF5) by using a TAM air isothermal microcalorimeter. These results suggested that both MAA-CdSe QDs and MAA-CdSe/ZnS QDs were indeed acutely toxic for T. thermophila BF5 growth in a dose-dependent manner, and the toxicities of both MAA-CdSe QDs and MAA-CdSe/ZnS QDs increased dramatically after UV irradiation due to the liberation of more toxic Cd2+, which indicated that the toxicity of MAA-CdSe/ZnS QDs was less than that of MAA-CdSe QDs. Furthermore, the toxicity of different ligands-capped CdSe/ZnS QDs on T. thermophila BF5 was also investigated. The uptake of MAA-CdSe/ZnS QDs and adenosine 5′-monophosphate (AMP)-CdSe/ZnS QDs by cells and the morphological change during the process of T. thermophila BF5 growth incubated with these QDs were further studied by fluorescence inverted microscopy.

Preparation and Biological Effect of Nucleotide-Capped CdSe/ZnS Quantum Dots on Tetrahymena thermophila

In this paper, we described the preparation and characterization of different types of modified CdSe/ZnS quantum dots (QDs) and explored the biological effects of QDs with different surface modifications on the whole growth of unicellular protozoan Tetrahymena thermophila BF(5) using a thermal activity monitor air isothermal microcalorimeter. Our results demonstrated that adenosine 5'-monophosphate (AMP) showed stronger interaction with QDs than other types of nucleotide. AMP-QDs could stimulate the growth of T. thermophila while mercaptoacetic acid-capped CdSe/ZnS quantum dots inhibited it. In addition, the population density determination and fluorescence imaging of T. thermophila BF(5) also confirmed the results obtained from microcalorimetry. It is believed that this approach will provide a more convenient methodology for the kinetics and thermodynamics of microorganism when coexisting with QDs in real time, and all of which are very significant to understanding the effect of QDs to organism.

Toxic effects of protoberberine alkaloids from Rhizoma Coptidis on Tetrahymena thermophila BF5 growth based on microcalorimetry

Rhizoma Coptidis consists mainly of protoberberine alkaloids (PAs), and has been used for many years as a traditional medicine. Recent research revealed the toxicity of Rhizoma Coptidis, but studies focusing on the relationships between the structures of PAs and their toxicities are lacking. The toxic effects of four PAs from Rhizoma Coptidis on the growth of Tetrahymena thermophila BF5 were investigated by microcalorimetry. The power-time curves of T. thermophila BF5 with and without PAs were obtained; the extent and duration of toxic effects on the metabolism of this organism were evaluated by studying thermokinetic parameters and the half-inhibitory ratio (IC 50). All the thermokinetic parameters showed regular variations with alteration of PA concentrations. The magnitude of the toxic effects of PAs was ascertained from IC 50 values: palmatine > jateorhizine > berberine ≈ coptisine. The structure–function relationship of PAs indicated that the C2 and C3 positions contributed more to the toxic effect of PAs. That is, when substituted with methoxyl groups, the toxic effect would be increased.

Microcalorimetric Investigation of Toxic Effects of Three Injectable Solubilizing Excipients on Tetrahymena thermophila BF5 Growth

AbstractUsing microcalorimetry, thermal metabolic curves of Tetrahymena thermophila BF5 (T. thermophila BF5) growth at 28°C affected by three injectable solubilizing excipients (ISE) including tween 80, hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) and poloxamer 188 were measured. Meanwhile, the toxicities of three ISE were evaluated by dynamic parameters of thermal metabolic curves. In addition, the irritative effects of the ISE on myoblast L6 cells were investigated to show their cytotoxicities by biochemical method. The results indicated that the effects of the ISE on T. thermophila BF5 varied for different ISE. 5% inhibition concentration values (IC5) of the ISE were 1.33, 1.83 and 1.64 mg/mL for tween 80, HP‐β‐CD and poloxamer 188, respectively. By the principal component analysis (PCA), the total quantity of heat (Q), growth rate constant (k) and second maximum power (P2) were selected as the main characteristic parameters to present their toxicities, there were good linear relationships between Q, k, P2 and concentrations c, suggesting that the toxicities of the ISE on T. thermophila BF5 were closely linked to their concentrations. The results of creatine kinase (CK) bioassay of myoblast L6 cells indicated that the sequence of irritative effects of the ISE was HP‐β‐CD<poloxamer 188<tween 80, which added to the results obtained from microcalorimetry.

Microcalorimetric investigation of the toxic action of berberine on Tetrahymena thermophila BF5

Tetrahymena thermophila (T. thermophila) BF(5) produces heat through growth and metabolism. By microcalorimetry, the power-time curves of the metabolism of T. thermophila BF(5) at 28 °C were measured and some quantitative parameters were obtained from these curves. Then the action of berberine on this microbe was investigated. Furthermore, the minimum inhibitory concentration (MIC) of berberine against T. thermophila BF(5) growth was obtained by tube dilution method. Berberine of different concentrations had various actions on T. thermophila BF(5) growth: a low concentration (25 μg/ml) of berberine began to inhibit the growth of T. thermophila BF(5) and a high concentration (450 μg/ml) of berberine completely inhibited T. thermophila BF(5) growth. The toxic action of berberine could also be expressed as half-inhibitory concentration IC(50), i.e., 50% effective in this inhibition. The value of IC(50) was 175.60 μg/ml, while the MIC of this compound against T. thermophila BF(5) was 20.76 mg/ml. Berberine has strong toxic action on T. thermophila BF(5) growth. The microcalorimetric method for the assay of toxic action is quantitative, inexpensive and versatile.

The toxic effect of solubilizing excipients on Tetrahymena thermophila BF5 growth investigated by microcalorimetry

The toxic effect of different solubilizing excipients on the growth and metabolism of Tetrahymena thermophila BF5 (T.t.BF5) at various concentrations was investigated by microcalorimetry. The thermogenic curves of T.t.BF5 growth were determined at 28°C, and were evaluated by dynamic parameters. The results indicated that the values of growth rate constant (k), maximum power (P1, P2), peak time (T1, T2) and total quantity of heat (Q) varied for different excipients. There was a good linear relationship between k and concentrations (r>0.95, P<0.01). 5% inhibition concentration (IC5) of poloxamer 188, Tween 80, PEG 600, PEG 400 and Tween 20 was 2.18, 1.07, 1.35, 0.58, and 0.045 mg/mL, respectively. After the principal component analysis (PCA), Q, k and P1 could characterize the effect of these excipients on T.t.BF5 growth. Comprehensive evaluation indicated that compared with the control group, poloxamer 188 had the weakest toxicity and Tween 20 had the strongest toxicity.

Microcalorimetric Investigation of Effect of Toad Bufanolide Diene on Tetrahymena Thermophila BF5 Growth

The effects of various concentrations of toad bufanolide diene(BD) on the growth of Tetrahymena thermophila BF5 were investigated by means of a thermal activity monitor(TAM) system.The extent and duration of toxic effects on metabolism were evaluated by studying the growth rate constant(k),maximum heat-output power(Pmax) and half inhibitory concentration(IC50).Experimental results showed that the values of k and Pmax decreased as the concentrations of BD increased.Furthermore,the growth rate constant(k) was linked to the concentration of BD:rcinobufagin= 0.9910(IC50=119.2 μg·mL-1);rbufalin=0.9923(IC50=106.14 μg·mL-1);rbufotalin=0.9977(IC50=73.80 μg·mL-1);rgamabufotalin=0.9923(IC50=54.75 μg·mL-1).The sequence of toxicity for the four BDs was:gamabufotalinbufotalinbufalincinobufagin.The α-hydroxy group at C11,β-hydroxy group at C14,β-acetoxy at C16 and the non-dehydrolysis between C14 and C15 can possibly improve the toxicity of BD towards Tetrahymena thermophila BF5.

Effects of Artemisinin Derivative on the Growth Metabolism of Tetrahymena thermophila BF5 Based on Expression of Thermokinetics

The toxic effects of artesunate and dihydroartemisinin on the growth metabolism of Tetrahymena thermophila BF5 were studied by microcalorimetry. The results showed that: (1) low concentrations of artesunate (<or=1 mg L(-1)) and dihydroartemisinin (<or= 2 mg L(-1)) promoted the growth metabolism of T. thermophila BF5, whereas high concentrations of artesunate (1-60 mg L(-1)) and dihydroartemisinin (2-60 mg L(-1)) inhibited its growth; (2) the half inhibition concentrations IC(50) of artesunate and dihydroartemisinin were 17.5817 and 9.5089 mg L(-1), respectively. It was concluded that the inhibition of dihydroartemisinin was stronger than that of artesunate.

Action of palmatine on Tetrahymena thermophila BF 5 growth investigated by microcalorimetry

Using a thermal activity monitor (TAM) air isothermal microcalorimeter with ampoule mode, the thermo-genic curves of the metabolism of Tetrahymena thermophila BF 5 growth at 28 °C were obtained and the action of palmatine on it was investigated. Meanwhile, the biomass change during the process of T. thermophila BF 5 growth coexisted with palmatine was studied by a haemacytometer. The results showed that a low concentration (50 μg/mL) of palmatine began to inhibit the growth of T. thermophila BF 5, and when the concentration of palmatine reached 600 μg/mL, T. thermophila BF 5 could not grow at all. The relationship between the growth rate constant ( k) and the concentration c was almost linear with the correlation coefficient of 0.9957, showing the strong toxic action of palmatine on T. thermophila BF 5 growth. The biomass during T. thermophila BF 5 growth decreased obviously by the addition of palmatine at different concentrations. The investigation of biomass agreed well with the results obtained by means of microcalorimetry.

Effects of ytterbium ion on the growth, metabolism and membrane fluidity of Tetrahymena thermophila

Power-time curves and metabolic properties of Tetrahymena thermophila BF5 exposed to different Yb3+ levels were studied by ampoule method of isothermal calorimetry at 28°C. Metabolic rate (r) decreased significantly while peak time (PT) increased with the increase of Yb3+. These results were mainly due to the inhibition of cell growth, which corresponded to the decrease of cell number obtained by cell counting. Compared with cell counting, calorimetry was sensible, easy to use and convenient for monitoring the toxic effects of Yb3+ on cells and freshwater ecosystem. It was also found that cell membrane fluidity decreased significantly under the effects of Yb3+, which indicated that Yb3+ could be membrane active molecules with its effect on cell membranes as fundamental aspect of its toxicity.

Bioenergetic Investigation of Action of Lithium to Tetrahymena thermophila bF5 by Microcalorimetry

Microcalorimetry was employed to investigate the action of Li(I) to aquatic ecosystem from the point view of bioenergetics. Tetrahymena thermophila BF5 was chosen as the model organism. The power-time curves of T. thermophila BF5 growth metabolism in the absence and presence of Li(I) were obtained. The corresponding thermokinetic parameters were derived. The generation time was calculated as 592.3 min, which was consistent with the biomass values. Low concentration of Li(I) (1-20 mmol l-1) stimulated the growth of T. thermophila BF5, whereas the inhibition effect was observed in high concentration (30-100 mmol l-1). The value of IC50 was 52.8 mmol l-1. In the concentration range of 30-100 mmol l-1, the growth rate constants (k) and the maximum heat out power (P max) decrease with the concentration of Li(I), whereas the heat output (Q) increases slightly compared to the control. Other than the classic mechanism of inositol-phosphate cycle, the involvement of mitochondria mechanism was discussed and suggested.

Microcalorimetric investigation of the toxic action of Cr(VI) on the metabolism of Tetrahymena thermophila BF 5 during growth

Tetrahymena thermophila BF 5 produce heat by metabolism and movement. Using a TAM air isothermal microcalorimeter, the power–time curves of the metabolism of T. thermophila BF 5 during growth were obtained and the action on them by the addition of Cr(VI) were studied. The morphological change with Cr(VI) coexisted and biomass change during the process of T. thermophila BF 5 growth were studied by light microscope. Chromium has been regarded as an essential trace element for life. However, hexavalent chromium is a known carcinogen, mutagen, cytotoxicant and strong oxidizing agent. Cr(VI) of different concentration have different effects on T. thermophila BF 5 growth with the phenomenon of low dose stimulation (0–3 × 10 −5 mol L −1) and high dose inhibition (3 × 10 −5 to 2.4 × 10 −4 mol L −1). The relationship between the growth rate constant ( k) and c is a typical U-shaped curve, which is a characteristic of hormesis. T. thermophila BF 5 cannot grow at all when the concentration of Cr(VI) is up to 2.4 × 10 −4 mol L −1. The microscopic observations agree well with the results obtained by means of microcalorimetry. And T. thermophila BF 5 had obviously morphological changes by the addition of Cr(VI).

Microcalorimetry as a possible tool for phylogenetic studies of Tetrahymena

Using isothermal microcalorimetry, the growth power-time curves of three strains of Tetrahymena were determined at 28 degrees C. Their Euclidean distances and cluster analysis diagram were obtained by using two thermokinetic parameters (r and Q(log)), which showed that T. thermophila BF1 and T. thermophila BF5 had a closer relationship. Compared with the single molecular biomarker (ITS1) method, microcalorimetry wasmaybe a simpler, more sensitive andmore economic technique in the phylogenetic studies of Tetrahymena species.