Jan J. Cybis* and Rowland H. Davis Department of Botany, University of Michigan, Ann Arbor, Michigan 48104 Received August 6,1974 summary: A radioactive assay was developed for the arginine-synthetic enzyme, acetylglutamate kinase (EC 2.7.2.8). Activity of the enzyme was demonstrated in crude extracts of Neurospora mycelium. Precipitation with ammonium sulfate, resulting in separation of the en...

The physiological properties of canavanine, a naturally occurring, structural analogue of arginine, have not been extensively investigated. Recently, Horowitz and Srb (1) found that canavanine inhibited growth of wild type Neurospora, and that the inhibition was competitively alleviated by arginine. Lysine and methionine were also effective in alleviating canavanine inhibition for certain strai...

In an analysis of 22 of the roughly 100 dispersed 5S rRNA genes in Neurospora crassa, a methylated 5S rRNA pseudogene, Psi63, was identified. We characterized the Psi63 region to better understand the control and function of DNA methylation. The 120-bp 5S rRNA-like region of Psi63 is interrupted by a 1.9-kb insertion that has characteristics of sequences that have been modified by repeat-induce...

A Neurospora in vitro transcription system has been developed which specifically and efficiently initiates transcription of a cloned Neurospora crassa ribosomal RNA gene by RNA polymerase I. The initiation site of transcription (both in vitro and in vivo) appears to be located about 850 bp from the 5' end of mature 17S rRNA. However, the primary rRNA transcripts are normally cleaved very rapidl...

Neurospora comprises a primary model system for the study of fungal genetics and biology. In spite of this, little is known about genome evolution in Neurospora. For example, the evolution of synonymous codon usage is largely unknown in this genus. In the present investigation, we conducted a comprehensive analysis of synonymous codon usage and its relationship to gene expression and gene lengt...

The ability of Neurospora crassa FGSC 4335 in the biotransformation of hydrocortisone was investigated. The microorganism produced two major metabolites after incubation with the substrate for seven days. Each microbial product was purified chromatographically and identified on the basis of spectral data. The products were identified as 11?,17?,20?,21-tetrahydroxypregn-4-en-3-one (II) and 11?-h...

The sulfur regulatory circuit of the filamentous fungus, Neurospora crassa, consists of a set of unlinked structural genes which encode sulfur catabolic and two major regulatory genes which govern their expression. The cys-3 regulatory gene encode a transacting regulatory protein which activates the expression of cys-14 and ars, whereas the other regulatory genes Scon-l and Scon-2 appear to...

Calcium ionophoresis into coenocytic cells of Neurospora crassa activates the plasma membrane proton pump as measured by current-voltage analysis. This is direct evidence that intracellular calcium regulates the activity of a key transport enzyme found in higher plants and fungi.