Sporothrix schenckii cells were grown on a medium containing yeast extract, neopeptone and glucose at 20 "C to obtain a mixture of mycelia and conidia, and at 35 "C to obtain yeast-like cells. The organism was maintained in the mycelial form, and its transformation to yeast at the higher temperature proceeded via conidia and 'intermediate cells' that then gave rise to yeast by a blastic mechanism. Cell-free extracts were analysed by PAGE at pH 8.0 and acid phosphatases (EC 3.1.3.2) were revealed by a sensitive detection reagent at pH 5.0. Mycelial, conidial and yeast extracts all had some acid phosphatase activity (M-I, C-I and Y-I) at the origin, although the proportion was highest for the yeast extracts. All of the bands that penetrated the gels had different electrophoretic mobilities. Mycelial and conidial extracts each had one other isoenzyme (M-I1 and C-11), while the yeast extracts had a total of five electrophoretically distinct acid phosphatases. Isoenzyme Y-I1 was further resolved into five closely related bands (Y-IIa to Y-He), the relative intensities of which varied with the phosphate nutrition of the yeast cells and the history of the extracts. The acid phosphatase isoenzymes were inhibited to various extents by sodium fluoride, L( +)-tartrate and phosphate, and showed interactions with citrate as opposed to acetate as the background buffer at pH 5.0.

Aspects of the culturally induced mycelial- to tissue-phase transformation of Penicillium marneffei were studied by electron microscopy of thin sections. The hyphal cell was observed to contain multiple, large lipid bodies scattered throughout the cytoplasm. Five days after induction of conversion, short elements arose which were characterized by the presence of two polar areas of vacuolation containing electron-opaque material thought to be altered lipid. This material could not be demonstrated with permanganate fixation, but reacted strongly with thiocarbohydrazide. The latter reagent is known to enhance the electron density of osmium-stained lipids. After 10 days incubation, the tissue-phase cells appeared to be slightly elongate with one or more septa present as the result of division by fission. The cell wall appeared to be of uniform electron opacity with a slightly roughened appearance to the outer surface. Except for residuals of polar vacuolation, the internal morphology of the tissue phase of P. marneffei appeared similar in many respects to that of the analogous yeast-like phases of certain other of the pathogenic dimorphic fungi.

A whole-body plethysmographic technique was developed and then used to detect experimentally induced asthma in guinea pigs and to assess pharmacological treatments of allergic and classically conditioned attacks. Inhalation of a beta adrenergic compound (isoproterenol) controlled both forms of attack. Atropine and methscopolamine, parasympathetic blocking agents, prevented conditional but not allergic attacks; diphenhydramine, an antihistamine, prevented allergic attacks; and methysergide, which blocks serotonin (which is believed to trigger human asthma), prevented neither. The guinea pig's allergic reaction is probably the result of a bronchospasm induced by histamine released in tissue of the airway by a local combination of allergen and antibody. The conditional attack is believed to be a constriction of the airway mediated by parasympathetic fibers of central origin.

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