Fimbriae of coprinus cinereus, schizophyllum commune and ustilago violacea = structural aspects and a role in conjugation

Surface fibrils (fimbriae) have been observed on fungi from every major group. Fimbriae are thought to be involved in the following cell to cell interactions: conjugation, flocculation and adhesion. Several higher fungi exibit two other types of interactions: hyphal fusion (anastomosis) and clamp connection formation. As a prelude to examining the role of fimbriae in these processes, the fimbriae of two fungi that undergo these fusion events were examined. Electron microscopy studies revealed that Coprinus cinereus and Schizophyllum commune are fimbriated. C. cinereus fimbriae were 5 nm in diameter and 0.5 to 20 11m in length. Fimbriae of C. cinereus oidia were more numerous and longer than those of the hyphal stage. S. commune fimbriae were also 5 nm in diameter, but were only 0.5 to 2 11m in length. There was an unequal distribution of fimbriae on the hyphal surfaces of S. commune . Fimbriae were sparsely distributed over the entire hyphal surface, with higher densities of fibrils present on the side growths of the hyphae found in the older sections of the mycelium. Antiserum raised against Ustilago violacea fimbrial protein (AU) crossreacted strongly with 37 and 39 kd C. cinereus mycelial proteins. In contrast, AU bound very weakly to 89 and 92 kd S. commune mycelial proteins. Since AU cross-reacted poorly with S. commune fimbrial proteins, it was impossible to further characterize the fimbriae of this specIes. The 37 and 39 kd C. cinereus proteins, were isolated by electroelution and were shown to be able to form fibrils the same diameter as oidial fimbriae. The 37 kd protein was shown to be composed of several proteins with isoelectric points ranging from pH 6.1 to 7.63. Furthermore, the 37 kd protein was found to be multimeric, while the 39 kd protein was not. These results strongly suggested that the 37 kd protein is the structural fimbrial protein of C. cine reus . Finally, a series of experiments were designed to determine whether fimbriae are required for conjugation in U. violacea Conjugation was inhibited significantly with AU, but not with pre-immune serum or AU preincubated with purified fimbrial protein. Thus, it was concluded that fimbriae play a central role in mating in this organism.

The Weekly Register Vol. III, No. 11, Whole No. 63- November 14,1812

The Weekly Register, also known as Niles Weekly Register, was a weekly periodical edited by Hezekiah Niles (1777-1839) and published in Baltimore Maryland. Volumes of interest were published between 1811 (Vol. 1, No. 1, September 7, 1811) to 1814 (Vol. 5, No. 26, February 26, 1814). These volumes focus primarily on 19th century politics and government in the United States of America. Niles edited and published the Weekly Register until 1836, making it one of the most widely-circulated magazines in the United States. The popularity also made Niles into one of the most influential journalists of his day. Devoted primarily to politics, Niles' Weekly Register is considered an important source for the history of the period. The Register also recorded current economics, technology, science, medicine, geography, archaeology, the weather, and stories of human interest. This issue is part of a bound book titled the Weekly Register 1812-1814. Pages are divided as follows: November 14, 1812- Pages 161-174 January 22, 1814- Pages 337-352 July 30, 1814- Pages 361-376 Look for other issues of the Weekly Register within the website.