Harry Lenas

Taha Toros Arşivi, Dosya No: 112-Pastahaneler, Bozacılar, Gazozcular, Börekçiler, Turşucular, Sucularİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Two visual pigments in a single photoreceptor cell: Identification and histological localization of three mRNAs encoding visual pigment opsins in the retina of the butterfly Papilio xuthus

This paper describes the localization of newly identified visual pigment opsins in the tiered retina of the Japanese yellow swallowtail Papilio xuthus. We first cloned three cDNAs encoding visual pigment opsins, PxRh1, PxRh2 and PxRh3, and then carried out histological in situ hybridization to localize their mRNAs in the retina. By combining the present data with our previous electrophysiological results, we concluded that both PxRh1 and PxRh2 correspond to visual pigments expressed in photoreceptor cells sensitive in the green wavelength region (green receptors), whereas PxRh3 corresponds to a pigment in red receptors. The in situ hybridization studies showed that some photoreceptor cells express two opsin mRNAs. In the ventral half of the eye, all green receptors in the distal tier were labelled by both PxRh1 and PxRh2 probes. The labelling by the PxRh2 and PxRh3 probes was detected throughout the eye in the proximal tier; in 18 % of ommatidia, the probes labelled the same photoreceptor cell. These results suggest that the possible co-localization of two different visual pigments will broaden the sensitivity spectrum of the photoreceptor cells

X-ray magnetic circular dichroism and photoemission study of the diluted ferromagnetic semiconductor Zn1−x_{1-x}Crx_xTe

We have performed x-ray magnetic circular dichroism (XMCD) and valence-band photoemission studies of the diluted ferromagnetic semiconductor Zn$_{1-x}$Cr$_x$Te. XMCD signals due to ferromagnetism were observed at the Cr 2p absorption edge. Comparison with atomic multiplet calculations suggests that the magnetically active component of the Cr ion was divalent under the tetrahedral crystal field with tetragonal distortion along the crystalline a-, b-, and c-axes. In the valence-band spectra, spectral weight near the Fermi level was strongly suppressed, suggesting the importance of Jahn-Teller effect and the strong Coulomb interaction between the Cr 3d electrons