Abstract. The Saccharomyces cerevisiae mutant strains blocked in the protein secretion pathway are not able to induce sexual aggregation. We have utilized the defect of aggregation to concentrate the secretion-deficient cells and identified a new gene which functions in the process of intracellular protein transport. The new mutant, usol, is temperature sensitive for growth and protein secretion. At the restrictive temperature (37°C), usol mutant accumulated the core-glycosylated precursor form of the exported protein invertase in the cells. Ultrastructural study of the mutant fixed by the freeze-substitution method revealed expansion of the nuclear envelope lumen and accumulation of the ER at the restrictive temperature. Abnormally oriented bundles of microtubules were often found in the nucleus. The US01 gene was cloned by complementation of the usol temperature-sensitive growth defect. DNA sequence analysis revealed a hydrophilic protein of 1790 amino acids with a COOHterminal 1,100-amino acid-long t~-helical structure characteristic of the coiled-coil rod region of the cytoskeleton-related proteins. These observations suggest that Usol protein plays a role as a cytoskeletal component in the protein transport from the ER to the later secretory compartments.

SUMMARYThe compound eyes of the eastern pale clouded yellow butterfly, Colias erate, contain three types of ommatidia (I, II and III), identifiable by the differing arrangements of pigment clusters around the rhabdoms. The pigment color is red in all ommatidial types except for type II ommatidia of females, where the pigment is orange. Intracellular recordings demonstrated that the spectral sensitivities of the proximal photoreceptors (R5-8) of all ommatidia in both sexes are strongly tuned by the perirhabdomal pigments. These pigments act as long-pass filters, shifting the peak sensitivities into the wavelength range above 600nm. Due to the sex-specific pigments in type II ommatidia, the spectral sensitivities of the R5-8 photoreceptors of females peaked at 620nm while those in males peaked at 660nm. The measured spectral sensitivities could be well reproduced by an optical model assuming a long-wavelength-absorbing visual pigment with peak absorbance at 565nm. Whereas the sexual dimorphism was unequivocally demonstrated for the ventral eye region, dimorphism in the dorsal region was not found. Presumably the ventral region is adapted for sexual behaviors such as courtship and oviposition.

Ligand-protected gold clusters with an asymmetric nature have emerged as a novel class of chiral compounds, but the origins of their chiroptical activities associated with helical charge movements in electronic...