Studies on the surface structure of fungi. 1. Chitin contents of the cell wall of several fungi

Abstract

The cell wall of many fungi contains chitin a polymer of N-acetylglucosamine. During the course of a study concerned with the surface structure of fungi, a number of fungal whole cells and their purified cell walls were analysed to measure their chitin contents. This report presents the results of quantitative analyses of chitin in several fungi and their susceptibility to phenol in relation to the changes of chitin content followed by the length of incubation (4-20 days).The results are as follows.1) Both the glucosamine hydrochloride obtained by hydrolysis of the chitin and standard D-glucosamine hydrochloride revealed identical absorption curves showing a distinct maximum value at 530mμ. The results are shown in Fig. 2.2) For this experiment, 4 fungal strains (Asperillus niger IAM 2020, Geotrichum candidum IFO 6454, Penicillium chrysogenum IFO 4626, Trichophyton rubrum IFO 5467) were used. Chitin contents of dry whole cell and purified cell wall were estimated quantitatively on each of 4, 8, 12, 16 and 20 daycultures which were grown in either synthetic or Sabouraud's medium by shaking culture. It was found that the chitin content increased gradually with the day of incubation. In addition to this, the chitin contents of 8 and 16 days old culture of all fungal strains were determined in purified preparations of cell walls which were obtained by means of sonic treatment. The purity of the cell wall was examined with several microscopic methods, such as fluorescence microscopy, phase-contrast microscopy and electron microscopy. The results are shown in Figs. 3 and 4, Photos 1 and 2 and Table 1.3) During 4-20 days incubation time of fungi, the changes of pH in the medium and the dry weight of ethanol precipitate of culture filtrate were estimated. The results are shown in Fig. 5 and Table 2.4) Without regard to the age of cultures or their chitin content, the susceptibility to phenol of two fungi (i.e. A. niger IAM 2020, G. candidum IFO 6454) was not changed. The results are shown in Table 3.