Kluyveromyces osmophilus, a new yeast species
In 1962 Dr. R. ANTOINE of Mauritius sent a number of yeast strains isolated from sugar for identification to the Yeast Division of the Centraalbureau voor Schimmelcultures at Delft. One of these strains is considered to belong to a new species for which the name Kluyverornyces osmophilus is proposed. It will be described in the following part. This yeast strain was conspicuous by forming oval to reniform spores which were easily liberated from the ascus. When first studied, sporulation was abundant. The picture of the spores in this paper. (fig 2) is an electron micrograph of ultra-thin sections of a preparation fixed at that time with osmic acid and uranyl acetate according to RYTER et al. (1958). Unfortunately, the sporulating ability has been lost after maintaining the yeast for two years on malt agar. The yeast, grown on malt agar, was investigated according to the methods of WICKERHAM (1951) and of LODDER & KREGERVAN RIJ (1952). As regards the fermentation and assimilation reactions some remarks can be made. Fermentation of a 2% (w/v) glucose solution in a Durham tube was rather slow, i.e. the insert tube was filled up with gas after 10--14 days' incubation at 25 ° C. A 10% glucose solution gave the same result after 5--7 days, while a 30% glucose solution had a gas-filled insert tube after 5 days. Apparently, in solutions with a higher sugar concentration the fermentation rate was high at an earlier period. The assimilation test with the auxanographic method gave positive results for glucose and galactose only. The assimilation test in a synthetic liquid medium with glucose as the sole source of carbon in a concentration of 0 .50, read after one week at 25 ° C, show-
Kluyveromyces—A new yeast genus of theEndomycetales
SummaryA new budding yeast has been isolated from soil. Its most striking feature is the formation, generally preceded by isogamous or heterogamous conjugation, of unusually large multispored asci. The organism possesses a strong fermentative ability, fermenting glucose, galactose, saccharose and raffinose for one-third. Nitrate is not assimilated. It forms a pellicle in malt extract. A pseudomycelium is also formed. Cytological examination showed the vegetative cells to be uninucleate. The relationship which this yeast shows with theDipodascaceae and, in particular, withDipodascus uninucleatus Biggs, is discussed. For the classification of the yeast the new genusKluyveromyces was created. For the species the nameKluyveromyces polysporus is proposed. The Latin diagnosis of both the genus and the species is given.
Control of the homopause level
Abstract This paper reviews the hypothesis that internal gravity wave breaking in the factor responsible for upper atmosphere turbulence generation and control of the number density at the homopause level. Available data from Mars and Earth support the hypothesis, originally introduced by Lindzen, that breaking thermal tides are responsible for the necessary turbulence. The lowest-order, equatorially trapped, westward-propagating diurnal tidal mode is the primary cause on the Earth, and lower-order westward-propagating semidiurnal modes are the primary cause on Mars. The frequencies and vertical wavenumbers of the responsible modes determine the eddy diffusion coefficients; energy density is only indirectly involved by determining which modes can break. A general scale relationship between tidal heating and velocity amplitude can be used to assess the breaking potential of tidal modes, and is used here as the basis for arguing that the number density at the Martian homopause is likely to have been stable over much of geologic time. Difficulties with this approach arise in the cases of Venus and Titan because of their peculiar zonal winds. For Jupiter and Saturn, internal gravity waves generated by nontidal mechanisms probably control the homopause.