The Structure and Mode of Division of the Nuclei in the Yeast Cells and Mycelium of Blastomyces Dermatitidis

Abstract

The nuclei in the yeast cells and mycelium of Blaston~yces dermatitidis were studicd in the living statc and in hxed preparations stained by various techniques. Yeast cells and mycelium are ~nultinucleate. Interdivisional and recently divided nuclei migrate into the yeast buds. Nuclear migration also occurs from one cell to another via the pores in the septa of elongated yeast cells and mycelium. Interdivisional nuclei in yeast cells and mycelium are composed of a spherical Feulgen-negative central body enveloped by grdnuldr Feulgen-positive chromatin. A nuclear membrane has not been observed surrou~tdir~g living or stained nuclei either in yeast cells or mycelium. During nuclear division. the chromatin condenses, then elongates, and finally pulls apart to form taro slster rluclei. The role played by the central body during nuclear division is obscure. However, it was noted that during the division of the chromatin the central body did not divide but became progressively smaller and apparently disintegrated in the cytoplasm. New central bodies are formed in recently divided nuclei. Mitotic figures such as a spindleor a metaphase plate have not been observed in any libing or stained prep,iratlons. Complexes of chromosome-like elements were noted in some hyphae, possibly those associated with conidial-bearing stallts. Counts made of such "chromosomes" in several of these complexes revealed a minimum number of six and a maximum of eight.' Manuscript

Nuclei in the somatic hyphae of Trichophyton mentagrophytes

“…Figs. 6,8,10,12,13). Nuclear migration in the hyphae of T. mentagrophytes was similar to that reported earlier by Dowding and Bakerspigel (25) and later by the writer in the report by Robinow and Bakerspigel (39).…”

“…However, nuclei in neighboring cells may either be in a different stage of division or, more commonly, interdivisional. It should be emphasized here that similar relationships were observed previously in the somatic hiphae of other imperfect fungi and in the basidiomycete, Sclzizoplzyllurn commune (6,10,12,13). In contrast, nuclei in somatic hyphae of phycomycetes, such as Endogone sphagnophila and species of Saprolegnia, as well as in the ascomycetes Gelasinospora tetrasperma and Neurospora crassa, do not divide simultaneously within the boundaries of a cell (7,8,9,11).…”

“…2, 9, 10, 12a, 30, 31) and the other contains the remaining nuclei (Figs. 6,7,28). Additional divisions occur followed by the production of more septa.…”

Somatic Mitosis in a Basidiomycete

“…For these reasons comparison of the staining procedure used here with that of other i~ivestigators may not explain their failure to clemonstrate mitotic figures. However, optimum staining with Giemsa's stain was achieved in 25 ~n i i i~~t e s in the present i~ivestigation, and the use of much longer periods described by other investigators (1,14) was found to give overstained preparations in which neither indiviclual chromosomes nor stages of division coulcl be distinguished.…”

Defence sugarcane glycoproteins disorganize microtubules and prevent nuclear polarization and germination of Sporisorium scitamineum teliospores

“…For example, condensed chromatin has a structural role in supporting nuclear movement and/or changes in the morphology of the nucleus (Gerlitz et al, 2013) which are required for important processes such as an efficient cell migration (Gerlitz and Bustin, 2010) and fungal mitosis, in which chromosomes must condense to migrate through the extension into the daughter (Straube et al, 2005). Furthermore, during nuclear division in yeast, the chro- matin condenses, then elongates, and finally pulls apart to form two sister nuclei (Bakerspigel, 1957).…”