The hydrogen exchange of coals with water was investigated using a tritium tracer method to estimate the mobility of hydrogen in coals. The reactions at several temperatures between 50 and 300 °C were carried out using a glass batch reactor and a pulse flow reactor, respectively. At lower temperatures, the ratio of hydrogen exchange of coal with water increased with a decrease in rank of coals and tended to change with respect to the content of functional groups such as hydroxyl group, thiol, amino group, and carboxylic acid in coal. From the results obtained from the hydrogen exchange of model compounds of the functional groups present in coal, it is proposed that the hydrogen only in the functional group was exchangeable at lower temperature while the hydrogen in aromatic ring substituted by functional groups also became exchangeable at 300 °C. It was found that the use of the pulse flow reactor as well as the glass batch reactor was very useful facile and convenient methods to trace the hydrogen exchange between coal and water.

Mating pheromones, known as a and alpha-factors, arrest the division of cells of opposite mating types, alpha and a respectively, in Saccharomyces cerevisiae. I have cloned the DAC2 gene, which is required for both pheromone-induced division-arrest and cell-fusion during conjugation. The constructed dac2::LEU2 null mutation leads to defects in both pheromone-induced division-arrest and cell-fusion during conjugation; it also suppresses the growth defect caused by the gpa1 mutation (a mutation in the alpha subunit of the S. cerevisiae G protein). These results indicate that DAC2 may be the same gene as FUS3, which was recently isolated by Elion et al. (1990) as a gene essential for cell-fusion during conjugation. The dac2::LEU2 null mutant also showed morphological alterations in response to mating pheromones. I show here that the DAC2 product plays an essential role in both the division-arrest signalling pathway of the yeast pheromone response and in cell-fusion during conjugation.

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A peptide, termed ask2 pheromone, was isolated from culture filtrates of mating type a cells of Saccharomyces kluyveri as a mating pheromone, having both shmoo inducing (in a cells of S. kluyveri and S. cerevisiae) and agglutinability inducing (in a cells of S. cerevisiae) actions. The amino acid sequence of Ly sk2 pheromone was determined as H-Trp-His-Trp-Leu-Ser-Phe-Ser-Lys-Gly-Glu-Pro-Met-Tyr-OH by mass spectrometry, sequence analysis and enzymatic digestions. Saccharomyces kluyveriMating pheromone

I have isolated a new type of sterile mutant of Saccharomyces cerevisiae, carrying a single mutant allele, designated dac1, which was mapped near the centromere on chromosome VIII. The dac1 mutation caused specific defects in the pheromone responsiveness of both a and alpha cells and did not seem to be associated with any pleiotropic phenotypes. Thus, in contrast to the ste4, ste5, ste7, ste11, and ste12 mutations, the dac1 mutation had no significant effect on such constitutive functions of haploid cells as pheromone production and alpha-factor destruction. The characteristics of this phenotype suggest that the DAC1 gene encodes a component of the pheromone response pathway common to both a and alpha cells. Introduction of the GPA1 gene encoding an S. cerevisiae homolog of the alpha subunit of mammalian guanine nucleotide-binding regulatory proteins (G proteins) into sterile dac1 mutants resulted in restoration of pheromone responsiveness and mating competence to both a and alpha cells. These results suggest that the dac1 mutation is an allele of the GPA1 gene and thus provide genetic evidence that the yeast G protein homolog is directly involved in the mating pheromone signal transduction pathway.