Taurine conjugates in the lipid fraction of Euglena cells and their mitochondria

Abstract

Dark-grown resting (non-dividing) cells of EugZena gracilis var. baciZZaris and mutants W,BUL (with a proplastid remnant) and W,,,BSmL (lacking plastids) incubated with 3sSOi-form a series of labelled lipids which are low or absent in dividing cells. These lipids all release labelled taurine on mild acid-hydrolysis. Treatment of the labelled lipids with 2,4-dinitrofluorobenzene (DNFB) followed by acid hydrolysis does not yield labelled dinitrophenyltaurine (DNP-taurine), but treatment with DNFB after hydrolysis readily forms labelled DNP-taurine, indicating that taurine is linked to the lipids by at least the amino group. Illumination increases the labelling of these taurolipids in plastid-containing cells (wild-type and W,BUL) but has little effect in cells lacking plastids (W,,,BSmL); labelling is highest in W,, cells irrespective of illumination. This indicates that the presence of a plastid may exert a negative control on taurolipid formation which is relieved by light. The same series of labelled lipids is found in isolated purified mitochondria from mutant W,,, indicating that this organelle is a site for taurolipid deposition, The formation of taurolipids under non-dividing conditions may be a response to nutritional stress and these negatively charged constituents (as well as the thylakoid sulpholipid) may serve to protect membranes by repelling deleterious negatively charged oxygen species.

Taurine transport systems in the ciliate protozoanTetrahymena pyriformis

“…Taurine has, however, been identified in Tetrahyrnena grown in a broth medium as a component of a group of membrane lipids termed taurolipids. A similar group of taurolipids has recently been identified in the flagellate Euglena (Saidha, 1993). A similar group of taurolipids has recently been identified in the flagellate Euglena (Saidha, 1993).…”

Predator lipids induce paralytic shellfish toxins in bloom-forming algae

“…1A and Fig. S2) makes copepodamides members of a little-known class named taurolipids, previously only found in the protozoans Tetrahymena (19) and Euglena (20), as well as in marine sponges (21) and sea urchins (22). The function of copepodamides is not known, but taurolipids in protozoans have been suggested to act as emulsifiers in digestive vacuoles (23), and taurine-conjugated compounds are involved in digestion in many other animals (24).…”

Sulfonate-sulfur assimilation by yeasts resembles that of bacteria

“…Some recent interest in biodegradability of sulfonate-containing detergents has focused on chain breakdown or loss of ring structure rather than on the fate of the sulfonate 74 sulfur [9][10][11]. Most of these studies have been conducted on bacteria, although there are few reports on sulfonate metabolism by eukaryotic microorganisms such as the green alga Chlorella [12,13] and the protozoan Euglena [14]. Nothing is known about the utilization of these sulfur-containing molecules by other eukaryotic microorganisms.…”