Ploidy differences inSporobolomyces salmonicolor andCandida albicans

Presumed diploid and haploid cultures ofSporobolomyces salmonicolor andCandida albicans were analysed for their DNA content per cell. Ratios of approximately 2 1 were obtained by relating the DNA content of the two phases to ploidy.The authors gratefully acknowledge Miss D. C. Wilkins' capable technical assistance.     

Phospholipid Composition of Bacillus subtilis

Bacillus subtilis contained at least five phospholipids, four of which have been isolated and identified as a polyglycerol phospholipid, probably cardiolipin, phosphatidylglycerol, phosphatidylethanolamine, and lysylphosphatidylglycerol. Further purification of the latter phosphoglyceride was obtained by high-voltage electrophoresis, and it was shown that this treatment removed amino acid-containing, nonlipidic material from the phosphoglyceride. This associated material, which is not covalently linked to the lipid, gave rise to minor amounts of a number of amino acids, other than lysine, in acid hydrolysates of the lysylphosphatidylglycerol. The phospholipid composition of B. subtilis appeared to depend on the growth conditions. Addition of glucose to the medium lowered the pH during growth; this was accompanied by an increase in the amount of lysylphosphatidylglycerol and a decrease in the phosphatidylglycerol content, when compared with growth at neutral pH. The amount of the other phospholipids and the total amount of phospholipid remained constant under the different conditions. The shape and the osmotic susceptibility of the protoplasts of this organism appeared to depend on the growth conditions. Cells harvested from a neutral growth medium gave spherical protoplasts which lysed rapidly, whereas cells grown in an acidic medium maintained their rod-shaped form to a great extent after the cell wall had been removed, even after being suspended in a hypotonic medium. The latter observation suggests the presence of a more rigid membranous structure in cells which have been exposed to a low environmental pH during growth.     

Triploid-diploid mosaicism in the lymphocytes of a liveborn child with multiple malformations

Summary A new case of triploid-diploid mosaicism in the lymphocytes of a newborn with multiple malformations is reported, and the origin of the mosaicism is briefly discussed.N.I.H. International Post-doctoral Fellow.Bevoegd Navorser N.F.W.O.     

Cellular localization of 3H-oestradiol in the hypothalamus

Summary The hypothalamus of male and female rats, given 0.3 g/100 g body weight of 6.7-³H-oestradiol-17 and killed 1 hour after the injection, was examined by autoradiography in order to 1) localize the areas and the cells involved in the uptake of the hormone, and 2) study the intracellular localization of the labelled material.Only nerve cells contained radioactive material while glial and ependymal cells were not significantly labelled. In the anterior hypothalamus, labelled nerve cells were concentrated in areas corresponding to nucleus preopticus medialis and nucleus preopticus, pars suprachiasmatica. The nucleus supraopticus was unlabelled. In the medial basal hypothalamus, neurons corresponding to the nucleus arcuatus and the lateral part of the nucleus ventromedialis showed marked labelling. No significant labelling was observed in the nucleus paraventricularis, pars magnocellularis.Although the individual nerve cells varied in their extent of labelling, the major proportion of the silver grains were consistently concentrated over the nuclei. Castration was not found to influence the results. The findings were essentially the same in male and female rats and appear to suggest that oestradiol exerts a direct effect on nerve cells in certain hypothalamic areas.This work was supported by grants from the Norwegian Cancer Society, Nordisk Insulinfond and Anders Jahres Fond. The skilful assistance of Miss Helga Friedl and Mrs. Jane Larsen is gratefully acknowledged.     

Multivariate analyses of Canadian and Japanese populations ofGlycyphagus destructor (Schrank) (Acarina,Glycyphagidae)

Summary Two multivariate statistical procedures were used to determine the basic trends of morphologic and geographic variations between males of a common stored-grain mite,Glycyphagus destructor (Schrank) collected from Canada and Japan. All analyses were carried out on physical measurements of 25 morphological features. Three principal component analyses bases on the Canadian (50 specimens), Japanese (50 specimens) and the combined populations from the 2 countries (100 specimens) revealed that the first component, accounting for 40% of the variability in all 3 solutions represented a measure of the morphologic dimension of the body. The second component, which explained over 18% of the variability, is a measure of the leg dimension. Smaller clusters of variates characteristic of the population from each county were also evident. Discriminant analysis, performed with the Canadian and Japanese populations, identified the variates that differed between the 2 populations and provided an approximate appraisal of interrelations. The general conclusion based on these analyses is that the Canadian and the Japanese populations are morphologically distinct. The difference is most evident in the diameters of genu 2, lengths of the sensory seta W_I, lengths of the body, and the distances between the vertical external setae. Contribution No. 446, from Research Station, Canada Department of Agriculture, Winnipeg, Manitoba, Canada.     

Seasonal changes in endocrine organs of the male common frog,Rana temporaria

Summary The annual cycle of the five morphological cell types in the pars distalis of the adenohypophysis of male common frogs,Rana temporaria, was studied in variously stained sections of the pituitary, collected at monthly intervals. All cell types showed a maximal development at the end of hibernation, a strong extrusion of secretory granules in the breeding season, and a more gradual release during later spring and early summer. A minimal development occurred in mid-summer, and a restoration followed in autumn and the hibernation period. During the phase of extrusion production was low, and vice-versa. These seasonal changes correspond with those of the testes and interrenal tissue of the same animals as well as with those of the thyroids and other endocrine tissues, and seems to be an important part of the biphasic annual life cycle of the species.The authors gratefully acknowledge the patient and skilful technical assistance of MissFemmy Brands. They thank Mr.H. van Kooten for making the photographs.     

Electron microscopical and histochemical observations on the relation between medio-dorsal bodies and neurosecretory cells in the basommatophoran snails Lymnaea stagnalis,Ancylus fluviatilis,Australorbis glabratus and Planorbarius corneus

Summary In Basommatophora medio-dorsal bodies (MDB) are closely attached to the cerebral ganglia, in which, just underneath the bodies, groups of Gomori-positive neurosecretory cells (MDC) occur. It has been suggested that the MDB-cerebral ganglion complex should be regarded as a neuro-endocrine association.In the present study the morphological relation between MDB and the ganglion is histochemically and ultrastructurally investigated in Lymnaea stagnalis, Ancylus fluviatilis, Australorbis glabratus and Planorbarius corneus.Histochemical tests showed the paraldehyde-fuchsin positive material of fibers in the MDB to be different from the neurosecretory material (NSM) in the MDC. At the ultrastructural level no penetration of nerve cell processes through the perineurium, separating the MDB from the ganglion, into the medulla of the MDB was observed. However, excepting for Lymnaea, the perineurium at these places shows particular differentiations. In the medulla of the MDB granule laden profiles (granule ø 700–900 Å) occur. They appeared to be processes of MDB cells.From these results it is concluded that the medulla of the MDB should not be regarded as a neurosecretory neuropile. Apparently, the MDB-cerebral ganglion complex is no neuroendocrine association. Probably the MDB is an endocrine organ. The small electron dense granules of the profiles in the medulla were also found in the MDB cell bodies. They are thought to represent a secretion product. The close morphological relation between MDB and cerebral ganglion may be connected with the origin of the MDB cells from perineural elements.