Ether-soluble "oils" of specific gravity > 1 were produced extracellularly in yields of over 16 gm./liter fermentation mixture by strains of Ustilago zeae growing in shaken flasks on medium containing cerelose, urea, and sugar beet molasses. The bulk of the oily material was shown to be a glycoside of mannose and erythritol, and in addition, itaconic acid and dianthrone were shown to be present. Yields of itaconic acid as determined by a bromine–iodine method at pH 1.2 (Friedkin) reached values of over 15 gm./liter but such values were considerably higher than those indicated by quantitative isolation of this acid. One hundred and eighty isolates of Ustilago were grown on medium with and without calcium carbonate and some 45 isolates produced extracellular oily material, 98 produced ustilagic acid, and 50 produced both crystals and oil. Ether-soluble substances from freeze-dried fermentation mixtures of different isolates ranged from 1 to 12 gm./liter, while methanol-soluble substances from ether-extracted freeze-dried fermentation mixtures ranged from 1 to 45 gm./liter.
for preparation of lignified coleoptiles and the suggestion that larger quantities of eugenol lignin could be produced on potato parenchyma. He is grateful to Mrs M. Szilagyi for technical assistance. The microanalyses were carried out by the Australian Microanalytical Service.
Thin sections of embryonic avian bone decalcify during preparation for electron microscopy, creating a false impression of mineral distribution. The results of the experiments reported herein show that viscous embedding materials do not penetrate compact formed bone, and so, in thin sections, the calcium apatite crystals may be leeched out by water, both in the collecting trough and in aqueous solutions of stains used to enhance tissue electron opacity. To prevent decalcification, a simple technique is described in which the aqueous fluids that come in contact with thin sections are saturated with respect to calcium and phosphate ions, thereby preventing solution of the bone mineral. The theoretical basis of this technique is briefly discussed.
Griseofulvin [7chloro-4:6:2'-trimethoxy-6'methylgris-2'-en-3:4'-dione (I:R, R', Me)], a product of Penicillium gri8eofulvum Dierckx, was first isolated by Oxford, Raistrick & Simonart (1939): its structure was first established by Grove, Ismay, MacMillan, Mulholland & Rogers (1951). This compound has fungistatic activity and was reported to control experimental ringworm in guinea pigs (Gentles, 1958) and in calves (Lauder & O'Sullivan, 1958) when administered orally.
The phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA), at nanomolar concentrations, induces rapid (t1/2 approximately 30 s) protrusion of multiple petal-shaped lamellae by neutrophil leucocytes. Lamellae are richly endowed with actin filaments as determined by the localization of rhodamine-phalloidin, suggesting extensive assembly at the cell cortex. Direct measurement of the proportion of total cell actin which is polymerized, by using a deoxyribonuclease I inhibition assay, indicates that the proportion of polymerized actin approximately doubles, and that assembly initiated by 30 nM TPA occurs with no obvious lag phase and with a t1/2 of about 30 s. A half-maximal response was induced at 2 nM TPA. Since both actin assembly and protrusion of lamellae are completely inhibited by 10(-6) M cytochalasin D, protrusion of lamellae is presumably dependent on actin filament assembly. To examine whether TPA induces actin assembly via changes in [Ca2+]i or pHi, these parameters were monitored in cells loaded with the fluorescent indicators quin2 and quene1 respectively. Addition of TPA caused no change in [Ca2+]i but a biphasic change in pHi. To examine further the potential role of ionic changes in regulation of actin assembly, the morphological responses of cells to TPA were monitored in severely Ca2+-depleted cells, or cells in which pHi had been experimentally raised or lowered by simultaneous additions of a weak base (NH4Cl) or weak acid (CH3COONa) respectively. The protrusion of lamellae induced by TPA was completely unaffected by these experimental manipulations indicating that TPA can directly regulate actin assembly, and hence morphology, by mechanisms essentially independent of [Ca2+]i and pHi.(ABSTRACT TRUNCATED AT 250 WORDS)
SUMMARY
Procedures for preparing gold colloid particles stabilized with either avidin or protein A are described. Methods of using these general utility tracers for localizing biotinylated and fc bearing immunoglobulins are outlined and, as examples of the way in which these methods can be applied, procedures for identifying epidermal growth factor receptors and surface fibronectin on ovarian granulosa cells are described.
A water-soluble compound formed by Ustilago sp. (PRL 627) in aerobic, submerged culture has been identified as D-mannopyranosyl-1-meso-erythritol. The extracellular "oil" produced at the same time by this fungus contains D-mannose, meso-erythritol, acetic acid, and a number of saturated and unsaturated fatty acids, probably as a mixture of D-mannosido-meso-erythritol residues to which the various acids are joined by ester linkages.
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