Fine structure of the cell surface and Golgi apparatus of Ochromonas

Ochromonas danica has an unusually flexible cell surface capable of producing projections of varying sizes and shapes: large projections, 340-360 nm long, and small projections, 50-110 nm long. These projections have been demonstrated by transmission and scanning electron microscopy; some of them may break off into the medium and be the source of extracellular membranes and vesicles reported in the cell-free O. danica growth medium. Ruthernium red stained the acid mucopolysaccharide layer just outside the cell surface as well as small blebs at the cell surface. The Golgi complex of O. danica, Ochromonas malhamensis, Ochromonas sociabilis and Ochromonas sp. produced small coated vesicles which may move toward and fuse with the plasma membrane. The role of the several vesicles is unknown but possible functions are discussed.     

Photochemical reaction of chlorophyll biosynthesis at 4.2 K

Phototransformation of protochlorophyllide in etiolated leaves was shown to take place at 4.2 K. Upon illumination of the sample a photoactive form PChlide₆₅₀ was transformed into a non-fluorescent intermediate which was then transformed into fluorescent forms of chlorophyllide (Chlide) upon increase of temperature in the dark. Reported transformations are similar to those observed under illumination at 77 K.     

Halobacterium salinarum strain MMD047-A low-salt adapted member of the Halobacteriaceae?

In a paper recently in Biotechnology and Bioprocess Engineering (vol. 14, pp. 67–75), Shanmughapriya and coworkers described a prokaryote (strain MMD047) isolated from a marine sponge, which they classified as a strain of Halobacterium salinarum. As the strain grows at low salinity only, its behavior is greatly different from that of other Halobacterium isolates. In spite of multiple requests, the strain has not been made available for further studies and we therefore call upon the authors of the paper to release their interesting isolate for an in-depth taxonomic characterization.