Colonies of Schizosaccharomyces pombe that contain ascospores (e.g., colonies of homothallic strains) turn black after treatment with iodine vapors. Heterothallic strains of S. pombe normally do not show this reaction. In experiments with the latter strains we found mutants which exhibit a positive iodine reaction though they do not contain ascospores. This phenotype is due to mutations in a ne...

Mutants defective in various steps of the sexual cycle have been isolated from homothallic strains of Schizosaccharomyces pombe by BRESCH, MULLER and EGEL (1968). These mutants include heterothallic h+ and hstrains. We have isolated additional h+ and hmutants from homothallic strains. Those mutants which are due to mutations in the mating-type region were analyzed in detail. Our results show th...

Immature asci of Coniochaeta tetraspora originally contain eight uninucleate ascospores. Two ascospore pairs in each ascus survive and mature, and two die and degenerate. Arrangement of the two ascospore types in individual linear asci is what would be expected if death is controlled by a chromosomal gene segregating at the second meiotic division in about 50% of asci. Cultures originating from...

∗ Corresponding author Albino strain KB20M1 of Monascus purpureus was genetically transformed to hygromycin B resistance with cosmid pMOcosX, using biolistic bombardment. Conidia and mycelial fragments were used as the recipient material and rupture disk strengths of 6.2 and 9.3 MPa each yielded a transformed isolate from five bombardments. Southern analysis suggested a single copy of the cosmi...

OLLOWING the extensive analysis of the gene-enzyme relationships of the Ftryptophan pathway in bacteria (YANOFSKY and LENNOX 1959; BLUME and BALBINDER 1966) in Saccharomyces and in Neurospora (BONNER, DE Moss and MILLS 1965), it has become O€ interest to examine the pathway in the homothallic ascomycete Aspergillus nidulans (Eidam) Wint. This paper describes the complementation behaviour of try...

Sexual reproduction is notoriously complex in fungi with species able to produce sexual progeny by utilizing a variety of different mechanisms. This is even more so for species employing multiple sexual strategies, which is a surprisingly common occurrence. While heterothallism is relatively well understood in terms of its physiological and molecular underpinnings, homothallism remains greatly ...

Hybridization by spore conjugation was used to develop new and improved wine yeasts of Saccharomyces cerevisiae. The procedure was achieved with diploid, homothallic strains with high sporulation frequency and high spore viability. The method was verified by crossing flocculent and non-H(2)S-forming strains. Single-spore descendants of the hybrids were studied by tetrad analysis with regard to ...