Is Blepharisma hyalinum Truly Unpigmented?¹

Abstract

ABSTRACT. To answer whether Blepharisma hyalinum is truly unpigmented, the organism must be established in culture as pointed out by Giese in 1973. Accordingly, the present study deals with B. hyalinum kept in culture since its isolation in 1975. The organism still remains colorless after growth in the dark; however, it contains cortical granules resembling pigment granules in colored species. A comparative study was therefore undertaken of B. hyalinum and B. steini; both species have a compact macronucleus, though of different shape. Crude pigment was extracted with acetone from organisms grown in the dark for three weeks and the maxima were measured by absorption. Purified pigment was obtained from TLC‐plate preparations and the absorption maxima were measured after removal of lipids with chloroform. No maxima characteristic of blepharismin were found in extracts of B. hyalinum, but these were present in extracts of B. steini. Electron microscopy of the cortical region revealed membrane‐bound granules in both species; these granules differed in content but not in their capacity to extrude. In B. hyalinum all granules had a homogenous electron‐dense substructure; in B. steini the granules had a net‐like granulated substructure of varying electron density. This difference corresponds to that published on “pigment” granules in albino and pigmented strains of B. undulans. Our conclusions are that B. hyalinum is unpigmented (and a valid separate species) and that the cortical granules may serve other functions than that of storing blepharismin.

Taxonomy and phylogeny of three heterotrich ciliates (Protozoa, Ciliophora), with description of a newBlepharismaspecies

“…Blepharisma penardi sp. nov. can be clearly distinguished from its closely related congener, B. steini, by its higher number of somatic kineties (24-34 vs. 18-22 in the Korean population, 18-23 in the Austrian population, and c. 25 in the Danish population of B. steini), the size of the contractile vacuole (large and conspicuous vs. small and inconspicuous in B. steini) and the body shape (slender and sigmoidal vs. widely oval in B. steini) (Kahl, 1932;Larsen & Nilsson, 1983;Foissner, 1989;Al-Rasheid, 2001;Lee & Shin, 2009; Fig. 6B; Table 3).…”

“…6B; Table 3). Another possible difference is cell colour, that is, B. penardi is variable from colourless to dark-brownish whereas B. steini is invariably red in colour (Kahl, 1932;Larsen & Nilsson, 1983;Foissner, 1989;Al-Rasheid, 2001;Lee & Shin, 2009). In addition, the separation of these two species is strongly supported by molecular data, their SSU rDNA sequences differing by 28 nucleotides (98.26% similarity) (Schmidt et al, 2007).…”

Photosensitivity in the Ciliated Protozoon Loxodes: Pigment Granules, Absorption and Action Spectra, Blue Light Perception, and Ecological Significance1

“…Individual granules have diameters of 0.3 pm or slightly less. It is clear that the size, structure, and location of the pigment granules in Loxodes is remarkably similar to that in colored heterotrich ciliates such as Blegharisma (16) and Sfenfor (25). It is believed that in these ciliates too, the cell pigmentation is located in the pigment granules (25).…”

Photomovement in Motile Microorganisms—ii

“…Obviously, the red pigment is not the main photoreceptor since it has a major absorption peak at about 574 nm. In order to reveal the role of the obvious pigments the photoresponses in the related Blepharisma hyalinum were studied, which has been shown to possess the subpellicular granules although no red or yellow pigments have been found in them (Larsen and Nilsson, 1983).…”