Detecting membrane impairment caused by xenobiotics

Abstract

The toxicity of 14 substituted anilines and 15 aliphatic alcohols was assessed by the electrorotation of yeast cells. Depending on the applied frequency, control cells exhibit both anti‐ and cofield rotation. From this spectrum, a frequency was selected at which untreated cells do not rotate, but impaired cells rotate with the field. The experimental spectra are fully in accord with theoretical models of the rotational response, calculated on the basis of changes in membrane permeability. High correlations exist between rotational data and physiological and biochemical end points (growth rate, plasma membrane ATPase, purine transport of yeast cells, and antihemolytic assays with human erythrocytes). A Quantitative Structure‐Activity Relationship analysis was made, whereby rotation data from 23 phenols were included. The effects of all chemicals on cell rotation could be predicted by their lipophilicity. Some residuals and deviations could be accounted for by the inclusion of molecular weight or connectivity in the analysis. 4‐Nitrophenol was an outlier, having an effect at least one order of magnitude higher than predicted, suggesting a specific toxic mechanism. Based on lipophilicity and rotation data, the antihemolytic effect on erythrocytes could be accurately estimated. © 1993 John Wiley & Sons, Inc.

Fish thymocyte viability, apoptosis and necrosis: in-vitro effects of organochlorine contaminants

“…In evaluating the in vitro results as compared to in vivo immune functioning, the implications of the present study are that relatively high concentrations of potentially immunotoxic chemicals may alter thymus function and eventually disrupt normal haematopoiesis (Pauli et al, 1993). The fish thymus is separated from the surrounding water by a single layer of epithelial cells.…”

“…The fish thymus is separated from the surrounding water by a single layer of epithelial cells. The epithelial biomembrane surrounding the fish thymi constitute the initial site of interaction between the xenobiotic and the maturing immune cells (Pauli et al, 1993), and likely act as a physical and chemical barrier. This membrane's hydrophobic character makes it relatively impermeable to the passive passage of charged or polar molecules (Pauli et al, 1993).…”

“…The epithelial biomembrane surrounding the fish thymi constitute the initial site of interaction between the xenobiotic and the maturing immune cells (Pauli et al, 1993), and likely act as a physical and chemical barrier. This membrane's hydrophobic character makes it relatively impermeable to the passive passage of charged or polar molecules (Pauli et al, 1993). However, lipophilic and stable chemical agents such as the gamma-and beta-isomers of hexachlorocyclohexane and many PCB congeners, are expected to permeate the thymi epithelial biomembrane and accumulate.…”

Automatic cell electrorotation measurements: studies of the biological effects of low-frequency magnetic fields and of heat shock

“…The yeast used was Saccharomyces cerevisiae (strain RXII) obtained from the Department of Biophysics, Free University, Berlin. Electrorotation characteristics for this strain of yeast have been obtained previously by research groups in Germany and Bangor (Arnold et al 1988a, b, 1989, Hölzel and Lamprecht 1992, Huang et al 1992, Pauli et al 1993. The cells were grown in an aqueous medium (SYP) containing 5% sucrose (Oxoid), 0.5% yeast extract (Oxoid) and 0.5% peptone (Oxoid) at 30 • C in an incubator-shaker at 200 rpm.…”

“…The dielectric and electrorotation properties of S. cerevisiae have also been extensively investigated. Such studies include the effects of chemical exposure (Lopez et al 1984, 1985, Geier et al 1987, Arnold et al 1988a, b, Stoicheva et al 1989, Pauli et al 1993, Zhou et al 1996, differences between viable and non-viable yeast (Crane and Pohl 1968, Huang et al 1992 and changes in dielectric properties during batch culture (Arnold et al 1989, Kell et al 1990.…”