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.     

Influence of Bacterial Infection on Serum Enzymes of White Rats

Infection of white rats with Francisella tularensis (Pasteurella tularensis) and Salmonella typhimurium and exposure to the endotoxin of S. typhimurium stimulated significant increases in various serum enzymes including aldolase, lactate dehydrogenase, phosphohexose isomerase, isocitrate dehydrogenase, and glutamate-oxalacetate transaminase. The rates of changes in enzymatic activity after infection were directly related to the size of infecting dose and to the type of infective agent employed. Tularemic infection stimulated excessive changes in enzyme activity, whereas salmonellosis and endointoxication elicited less pronounced alterations of relatively short duration. Changes observed in serum enzymes after exposure to these agents reflect the severe liver damage and extensive systemic involvement noted in tularemia as opposed to more localized and less intensive tissue damage occurring during salmonellosis and endointoxication.     

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.     

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.     

Calorimetric measurement of free energy utilization by Nitrosomonas and Nitrobacter

Summary Calorimetric estimates of the utilization efficiency of the free-energy derived from substrate oxidation by cell suspensions of two nitrifying bacteria, Nitrosomonas and Nitrobacter, provided two ranges of values: 11 to 27% and 15 to 51%, respectively. About 15 to 30% of the utilized free-energy is used for driving endergonic reactions other than CO₂ fixation, probably the synthesis of polyphosphates.The molar heat of substrate oxidation does not seem to be influenced by the age of cells harvested during growth or by the length of the incubation period during which cells have been kept in a buffer suspension in a starved condition. The loss of respiratory activity measured either by oxygen uptake or heat evolution in the presence of the specific substrate, nitrite or ammonium, decreases according to kinetics which are influenced by the aerobiosis of the suspension. The viability of the starved cells decreases in a way which is similar to that of the respiratory activity. It seemed impossible to obtain cells which had lost their viability but kept the ability to oxidize their substrate.Two inhibitors of the respiratory chain, quinacrine and cyanide, are without effect on the molar heat of substrate oxidation and consequently on the free-energy utilization efficiency. 2.4 dinitrophenol did decrease the rate of heat evolution during substrate oxidation at concentrations at which the rate of oxygen uptake was not depressed, with the consequences that free-energy efficiency was apparently increased.