No abstract

The effects of several physical and chemical agents on the survival of Trichophyton mentagrophytes arthrospores were investigated. Although arthrospores of this dermatophyte were highly resistant to chilling and freezing, they were extremely susceptible to moderate heat (above 5000) and desiccation. This high susceptibility could be significantly reduced when they were dried in the presence of exogenous proteins. These arthrospores were markedly susceptible to glutaraldehyde. They appeared to be significantly more resistant than their hyphal counterparts to common antimycotics such as clotrimazole, griseofulvin, miconazole nitrate, and nystatin. Clinical and epidemiological implications of these observations are discussed.

The cell walls of many fungi contain chitin, a polymer of N-acetylglucosamine (Foster, 1949; Kent and Whitehouse, 1955). During the course of a study concerned with the biosynthesis of this polysaccharide, a number of fungi were analyzed for their chitin content (Blumenthal et al., 1955). This report presents the results of the survey. MATERIALS AND METHODS Fermentation methods. All fungi were grown in a medium containing the following components in 1,000 ml of distilled water: sucrose, 30.0 g;

D-Glucaric (8accharFc) acid, the naturally occurring dicarboxylic acid aualogue of D-glucose, can support the growth of a variety of microorganisms (den Dooren de Jong, 1926), particularly grcherlchia coli and related enteric bacteria (Kay, 1926). Initial studies on the intermediary metabolism of D glucarate shoved that when 3. coli is grown In glucarate or galactarate, both resting-cell suspensions and cell-free axtracts from this culture can convert 1 mole of glucarate to 1 mole of pyruvate and unidentified products in the presence of areenfte (Blumenthal and Campbell, 1958). Later the first step in this conversion was shown to involve dehydration by D-glucarate dehydrase (Blumenthal, 1960), resulting in a yield of both 2-lceto-J-deoxy-and 4-deoxy-5-keto-D-glucarate, the latter compound being the major product (Fish and Blumenthal, 1961). We now have evidence that two additional eusymee take part in the conversion of 1 mole of D-glucarate to 1 mole each of pyruvate and glycerate. These enzymes, which have bean partially purified from E.-coli extracts, are ketodeoqglucarate aldolase (Fish and Blumenthal, 1963) and tartronate seuialdehyde reductase (D-glycerate 3-dehydrogeuaee). The entire sequence for the catabolism of D-glucarate is showu in Pig. 1. gvidence substantiating this mechanism has been gained through stoichiometric analysis (Table 1) of reactions employing the partially purified 9. & enzymes.

The rodlet layer of the microconidial wall of Trichophyton mentagrophytes was isolated and partially characterized. The purified microconidial walls were first extracted with urea (8 M), mercaptoethanol (1%), and sodium dodecyl sulfate (1%) followed by enzymatic digestion with glusulase (snail intestinal enzymes) and purified (1-*3)-,8-D-glucanase and chitinase. The purified rodlet layer was 15 to 30 nm thick and accounted for approximately 10% ofthe original wall weight. The pattern of rodlet patches, as revealed by electron microscopy of freeze-etched preparations ofthe isolated layer, was essentially the same as that observed on the intact microconidial wall. The rodlet layer was found to be resistant to most of the common organic solvents, cell wall lytic enzymes, mild acid treatments, and surface-active agents, but was solubilized in boiling 1 N NaOH with concomitant disorientation of the rodlet patterns. A melanin or melanin-like pigment appeared to be intimately associated with this rodlet layer and was solubilized during a hot-alkali treatment. Protein (80 to 85%) and glucomannan (7 to 10%) were the major components of the rodlet layer. The rodlet layer did not contain any appreciable amounts of lipid or phosphorus.