Several conditional-lethal mutant alleles of the single-copy Saccharomyces cerevisiae f3-tubulin and actin genes were used to evaluate the roles of microtubules and actin filaments in the pheromone-induced extension of mating projections. Mutants defective in tubulin assembly form projections indistinguishable in appearance from those formed by wildtype cells. However, the tubulin mutants are unable to move their nuclei into the projections and to orient the spindle pole body associated with each nucleus toward the projection tip. Actin mutants are defective in spatial orientation of cell-surface growth required for formation of normal mating projections. Migration of nuclei into mating projections and Spa2p segregation to projection tips are also defective in actin mutants. Studies with abpl null mutants showed that the function of the Abplp actin-binding protein is either not required for projection formation or there are other proteins in yeast with similar functions. Our findings demonstrate that actin is required to restrict cell-surface growth to a defined region for pheromone-induced morphogenesis and suggest that nuclear position and orientation in mating projections depend on direct or indirect interaction of microtubules with actin filaments.

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The role of endogenous hydrogen sulfide (H2S) as an antioxidant regulator has sparked interest in its function within inflammatory diseases. Cigarette and alcohol use are major causes of premature death, resulting from chronic oxidative stress and subsequent tissue damage. The activation of the Nrf2 antioxidant response by H2S suggests that this novel gasotransmitter may function to prevent or potentially reverse disease progression caused by cigarette smoking or alcohol use. The purpose of this study is to review the interrelationship between H2S signaling and cigarette smoking or alcohol drinking. Based on the databases of cellular, animal, and clinical studies from Pubmed using the keywords of H2S, smoking, and/or alcohol, this review article provides a comprehensive insight into disrupted H2S signaling by alcohol drinking and cigarette smoking-caused disorders. Major signaling and metabolic pathways involved in H2S-derived antioxidant and anti-inflammatory responses are further reviewed. H2S supplementation may prove to be an invaluable asset in treating or preventing diseases in those suffering from cigarette or alcohol addiction.

Title of Thesis Titre de la thèseThe interaction of disulfiram and H2S metabolism in inhibition of aldehyde dehydrogenase activity and liver cancer cell growth Name of Candidate Nom du candidat Read, Ethan