Effect of some soybean and bean phytoalexins and related isoflavonoids on growth of Candida albicans.
The influence of a series of related isoflavonoids on growth of the zoopathogenic yeast, Candida albicans, in liquid media was studied. The order of effectiveness was identical with that previously found for a range of phytopathogenic fungi. Minimum inhibitory concentration of phaseollinisoflavan, the most active test compound, was 250 microM for 3 days after inoculation. However, C. albicans resumed growth thereafter. Phaseollinisoflavan, 500 microM, did not inhibit but only delayed growth of the yeast. Tolerance of C. albicans to phaseollin and phaseollinisoflavan was based on nondegradative mechanism(s), while tolerance to glyceollin appeared to be based on detoxification.
Susceptibility of zoopathogenic fungi to phytoalexins
Phytoalexins are a group of low-molecular-weight antibiotics produced by higher plants in response to infection by relatively avirulent microorganisms. They are of relatively low toxicity for mammalian cells and have been reported to possess a broad spectrum of antimicrobial activity against bacteria and phytopathogenic fungi. Employing a broth dilution technique, we have found the zoopathogens Petriellidium boydii, Aspergillus flavus, A. fumigatus, Candida albicans, Coccidioides immitis, Cryptococcus neoformans, Histoplasma capsulatum, Rhizopus oryzae, Sporothrix schenckii, and Trichophyton rubrum to be inhibited by one or more of the phytoalexins maackiain, medicarpin, phaseollin, phaseollin isoflavan, pisatin, sativan, and vestitol in concentrations of from 12.5 to 50 microgram/ml. Phaseollin isofalvan was the most effective of these. In agar cup diffusion tests growth of the yeast form of Blastomyces dermatitidis was inhibited by phaseollin at 50 microgram/ml and by phaseollin isoflavan at 25 microgram/ml. Susceptibility of the mycelial form of B. dermatitidis to these two compounds was demonstrated by inhibition of radial extension on agar plates.
AN INTRODUCTION T O THE SOILS OF THE SOUTH-EASTERN PORTION OF THE AUSTRALIAN ARID ZONE
Summary 
 
Seven soil regions, each of which is dominated by soils belonging to one or two great soil groups, are defined and mapped. The outstanding feature is the presence of a variety of soils with widely differing characteristics. The soils are deeper, have more profile differentiation and are finer-extured than those in most-arid regions and are frequently overlain by currently-forming deposits of wind-transported materials. Because the vegetative cover is better developed and there are only small areas of rocky hills and bare rock pediments, water erosion and deposition are not as prominent as in other arid areas.