This set of pages on S pombe's experimental history comes from Frans Hochstenbach's original site in The Netherlands. Thanks to Frans for putting this together!
Schiz. pombe is classified as a fungus, namely an ascomycete fungus characterized by the formation of an ascus (for more information, see The Tree of Life Project). Over the past century, ascomycete fungi have been reclassified frequently, based on various phenotypic characteristics, such as the shape of the ascospore, type of cell division (budding versus fission), presence of hyphae, ability to ferment certain sugars or grow on various carbon and nitrogen sources.
Recently, DNA and RNA sequence analyses have been used to determine sequence divergence among ascomycete fungi and, thus, to quantitate genetic differences between species. These molecular techniques demonstrate that fission yeast Schiz. pombe is phylogenetically as distant from budding yeasts as it is from humans. The Schizosaccharomyces lineage separated about 1 billion years ago to form an ancestral branch of the ascomycetes, denoted archaeascomycetes (see description and illustration by B. Franz Lang, University of Montreal).
,-----archaeascomycetes-----------Schizosaccharomyces pombe | | ,------Saccharomyces cerevisiae ascomycete | ,----| fungi-----| | `------Candida albicans | ,-(budding) yeasts-| | | (hemiascomycetes)`-----------Pichia pastoris `--| | ,---Neurospora crassa `--filamentous ascomycetes-| (euascomycetes) | ,-Aspergillus nidulans `-| `-Penicillium chrysogenum
In 1893, P. Lindner was the first to describe fission yeast Schizosaccharomyces pombe. He isolated the yeast from East African beer, and chose as its epithet the Swahili word for beer, pombe. His isolate was a homothallic stain containing cells of both the + and - mating type, which can mate pair-wise and form asci containing four ascospores.
Over the years, many researchers have isolated Schiz. pombe, especially from sugar-containing fermentations from (sub)tropical regions. Yeast cells of many of these isolates were unable to mate and form ascospores; for example, isolates from arrack fermentations in Java described by A.G. Vorderman (1893) and C. Eijkman (1894) were asporogenous. M.W. Beijerinck (1897) thought these asporogenic isolates represented a distinct species, which he called Schizosaccharomyces asporus. However, Stelling-Dekker (1932) reclassified arrack yeast, represented by strain CBS 352, as the species Schiz. pombe; and in 1970, W. Ch. Sloof demonstrated that this strain of arrack yeast was a heterothallic strain of Schiz. pombe, containing only one mating type, which, he showed, was able to mate with heterothallic Schiz. pombe strains of the opposite mating type, namely CBS 358 and CBS 2628.
Beijerinck (1897) also isolated asporogenic strains of fission yeast, from currants and figs; however, these were non-sporulating strain of the species Schizosaccharomyces octosporus, which, as the epithet indicates, produces asci containing eight ascospores.
I chose the name Schizosaccharomyces on the one hand to give a meaningful expression to the essential difference that exists from a morphological standpoint in relation to the genus Saccharomyces, and, on the other hand, to take into account the common characteristics such as spore formation and fermentation capacity. P. Lindner, 1893
Division takes place along a transverse membrane that forms in the middle. The released ends round off, but the daughter cells nevertheless remain linked to each other at an angle. These V-shaped double-rods were compared aptly to the shape of a flail by Vorderman (1893), who was the first to describe them. C. Eijkman, 1894
If the unfortunate name 'pombe' did not have priority, its replacement with 'tetrasporus' would be very desirable. A good name is not a matter of indifference, especially when, as in this case, we are dealing with an organism of high scientific importance. M. W. Beijerinck, 1897
[Schizosaccharomyces liquefaciens] could certainly be useful in situations where the usual fermentation yeasts are killed off or inhibited in their growth by sulfuric acid for long periods; namely, in over-sulfurized fruit and grape juices, which are formed once in a while, ever since potassium sulfite is used in the production of wine. A. Osterwalder, 1924
On the basis of its strong gelatin-liquefying capability, Schiz. liquefaciens is henceforth to be classified as Schiz. pombe Lindner, var. liquefaciens (Osterwalder).
Interior pages: |
Original Lindner paper: Osterwalder ; (English translation, html)
Eijkman ;(English translation, html)
Beijerinck ;(English translation, html)
(Frans Hochstenbach prepared this background text, with advice from David Yarrow, Centraalbureau voor Schimmelcultures, the Netherlands. Interior pages and graphics also courtesy of Frans.)