Effects of food dyes on Paramecium caudatum: toxicity and inhibitory effects on leucine aminopeptidase and acid phosphatase activity

Noninvasive and safe cell viability assay for Paramecium using natural pigment extracted from food

Noninvasive, safe and cost-effective cell viability assay is important in many fields of biological research such as cell culture and counting. We examined ten typical natural pigments extracted from food to find that Monascus pigment (MP) or anthocyanin pigment (AP: purple sweet potato and purple cabbage) with Tris (Trimethylolaminomethane) works as a good indicator of viability assay for dye exclusion test (DET) of Paramecium. This was confirmed spectrally by scan-free, non-invasive absorbance spectral imaging A (x, y, λ) microscopy. We developed a new method of cell capture using a metal mesh to confine live Paramecium in a restricted space. This has the advantage that a low-cost and robust capture can be fabricated without using special equipment, compared to a conventional lab-on-a-chip. As a result, MP and AP stained dead cells as quick as methylene blue (MB), a synthetic dye conventionally used in DET within 1 min when treated with microwave and benzalkonium chloride. The natural pigments with Tris had little effect on inhibiting the growth of Paramecium, but MB killed all the cells within 1 h. MP is most useful because it allows non-invasive DET without Tris. This approach provides less invasive and safe DET.

Visible light induced degradation of pollutant dyes using a self-assembled graphene oxide–molybdenum oxo-bis(dithiolene) composite

An easily separable graphene oxide–molybdenum oxo-bis(dithiolene) ([Ph₄P]₂[MoO(S₂C₂(CN)₂)₂]) composite degraded Rhodamine B and Rose Bengal dye upon visible light exposure.

Sulforhodamine B interacts with albumin to lower surface tension and protect against ventilation injury of flooded alveoli

In the acute respiratory distress syndrome, alveolar flooding by proteinaceous edema liquid impairs gas exchange. Mechanical ventilation is used as a supportive therapy. In regions of the edematous lung, alveolar flooding is heterogeneous, and stress is concentrated in aerated alveoli. Ventilation exacerbates stress concentrations and injuriously overexpands aerated alveoli. Injury degree is proportional to surface tension, T. Lowering T directly lessens injury. Furthermore, as heterogeneous flooding causes the stress concentrations, promoting equitable liquid distribution between alveoli should, indirectly, lessen injury. We present a new theoretical analysis suggesting that liquid is trapped in discrete alveoli by a pressure barrier that is proportional to T. Experimentally, we identify two rhodamine dyes, sulforhodamine B and rhodamine WT, as surface active in albumin solution and investigate whether the dyes lessen ventilation injury. In the isolated rat lung, we micropuncture a surface alveolus, instill albumin solution, and obtain an area with heterogeneous alveolar flooding. We demonstrate that rhodamine dye addition lowers T, reduces ventilation-induced injury, and facilitates liquid escape from flooded alveoli. In vitro we show that rhodamine dye is directly surface active in albumin solution. We identify sulforhodamine B as a potential new therapeutic agent for the treatment of the acute respiratory distress syndrome.

Effect of novel phosphoramidate on growth and respiratory metabolism of Paramecium aurelia

The continuous increase in the number of new chemicals as well as the discharges of solid and liquid wastes triggered the need for simple and inexpensive bioassays for routine testing. In recent years, there has been increasing development of methods (particularly rapid tests) for testing environmental samples. This paper describes the quick toxic evaluation of a novel synthetic compound: Phosphoramidate derivative B at different concentrations (2, 4 and 8 μM) for 72 h on Paramecium aurelia. We showed that B concentrations affect the growth of Paramecium in concentration- dependent manner; also it decreases the growth rate and increases response percentage in concentration- dependent manner. The value of LC50 obtained for these protozoa was estimated at 4.9693 μM after 24 hours of exposure. The respiratory metabolism of protozoan is perturbed at three concentrations, noting that the oxygen consumption was significantly increased at high concentrations after 18 hours of exposure. The results indicate that the Paramecium toxicity assay could be used as a complementary system to rapidly elucidate the cytotoxic potential of insecticides. The major advantages associated with these tests are: inexpensive, simple, rapid and seem to be attractive alternatives to conventional bioassays

Induction of gamma-glutamyl transpeptidase and glutathione S-transferase in cultured fetal rat hepatocytes by laccaic acid and monascus pigments

The cytotoxicity of 8 natural dyes, commercially available as food additives in Japan, was studied on cultured fetal rat hepatocytes. Laccaic acid, one of the carminic acid samples and monascus pigments were found to be very toxic to cultured hepatocytes. Laccaic acid caused an increase in gamma-glutamyl transpeptidase activity. An 11-fold increase was seen 4 days after such addition, a significantly greater elevation than that produced by either the water or acetone solvents employed, or other dyes which have no toxic effects. On the other hand, monascus pigments had an increasing effect on both gamma-glutamyl transpeptidase and glutathione S-transferase, the later enzyme being elevated approximately 9 times greater than control values within 2-4 days. The increases in gamma-glutamyl transpeptidase and glutathione S-transferase activities by laccaic acid and monascus pigments could be inhibited by the simultaneous addition of either actinomycin D or cycloheximide. This suggests that the induction of these enzymes requires transcription and translation processes.