1973. Ultrastructural changes in the conidia of Penicilliurn notarllrn during germination. Can. J. Microbiol. 19: 797-801.To study the changes in the cell wall of Penicilliurn notaturn during germination, thin sections of resting, swollen, and germinating spores, and mycelium were compared with thin sections of the isolated cell walls. In the cell wall of resting spores four distinct layers were found. The outermost layer of the cell wall of resting spores was released during swelling and the two inner layers were extended to form the cell wall of the germ tube. The cell wall of young germ tubes had only two layers but a new electrondense layer was formed later on the outside. Mycelial cell walls which appeared thinner than those of conidia showed three distinct layers. Large mitochondria that divide during germination were present in both resting and swollen spores. Two different types of vacuoles were found, both of which decreased in size and in number during germination. Endoplasmic reticulum was almost absent in resting spores but increased substantially during swelling. MARTIN, J. F., F. URUBURU et J. R. VILLANUEVA. 1973. Ultrastructural changes in the conidia of Perricilliurn notatum during germination. Can. J. Microbiol. 19: 797-801. Pour ttudier les changements dans la paroi cellulaire de Penicillirlrn trotaturn au cours de la germination, nous avons cornpart des sections minces de spores au repos, en renflement et en germination, et de myctlium, avec des sections minces de parois cellulaires isoltes. Dans la paroi cellulaire des spores au repos, nous trouvons quatre couches distinctes; la couche la plus exttrieure est libtrte au cours du renflement, et les deux couches internes sont etendues pour former la paroi cellulaire du tube germinatif. La paroi cellulaire des jeunes tubes germinatifs a seulement deux couches, mais une nouvelle couche dense aux tlectrons est formte plus tard vers l'exttrieur. Les parois cellulaires du myctlium, lesquelles apparaissent plus minces que celles des conidies, montrent trois couches distinctes. Des grosses mitochondries, qui se divisent au cours de la germination, sont prtsentes dans les spores au repos, aussi bien que dans celles en renflement. Nous trouvons deux difftrents types de vacuoles, les deux dtcroissent en grosseur et en nornbre au cours de la germination. Le r6ticulum endoplasmique est presqu'absent dans les spores au repos, mais accroit substantiellement au cours du renflement.[Traduit par le journal]

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The process of regeneration of Candida utilis and Pichia polymorpha protoplasts obtained by means of an enzyme preparation from Streptomyces violaceus M R and an enzyme preparation from the snail (Helix pomatia) was followed with the electron microscope. A reticular network of fibrils making up a tube or surrounding the regenerating protoplasts was observed. The fibrils are glucan fibrils, and in C . utilis they are packed in groups of 5 or 6. P. polymorpha fibrils occurred singly. The fibrils are the framework for building the new cell wall. The relation between fibrils and plasmalemma particles is discussed.

Cell membranes of the yeast Candida utilis isolated by lysis of protoplasts have been shown to be lipoprotein in nature. Electron microscopy shows that Mg++ is responsible for maintaining the integrity of the membrane. A close serological relationship was found between membranes and cell walls isolated from the yeast. This relationship was exhibited not only by membranes obtained by strepzyme treatment but also by those obtained from the action of helicase enzyme. No such relationship existed between membranes and whole cells. Related data have been obtained by treatment of yeasts with different digestive enzymes. All of the results suggest that the protoplast membrane possesses traces of structural cell wall material. This material is detectable by serological tests, but not by electron microscopy.

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