Molecular characterization and expression analysis of the ß-actin gene from the ridgetail white prawn Exopalaemon carinicauda.

Actin is a highly conserved protein that is found in all eukaryotic cells, and has been widely used as an internal control gene in gene expression studies. In this study, we cloned an actin gene (named Ecß-actin) from Exopalaemon carinicauda and determined its expression levels. The full-length cDNA of Ecß-actin was 1335 bp long, comprising a 1131-bp ORF encoding 376 amino acids, a 65-bp 5'-UTR, and a 139-bp 3'-UTR with a poly(A) tail. The A + T content was approximately 79% in the 3'-UTR of the Ecß-actin mRNA. The 3'-UTR contained two repeats of the AUUUA motif. The putative protein Ecß-actin showed high identity (97-99%) with other actins from various species. Phylogenetic analysis revealed that Ecß-actin belongs to Crustacea, although it formed a singleton sub-branch that was located a short distance from crabs and other shrimp species. Ecß- actin expression was detected in the hepatopancreas, ovary, muscle, gill, stomach, and hemocytes, and was strongly expressed in the hemocytes and ovary of E. carinicauda. Ecß-actin mRNA expression varied during ovarian development, with high levels observed at stages I and V. Therefore, caution should be taken when using the Ecß-actin gene as an endogenous control gene.

Electronic structure of Eu(Fe0.79Ru0.21)2As2 studied by angle-resolved photoemission spectroscopy.

Eu(Fe(0.79)Ru(0.21))2As2 is suggested to be a nodeless superconductor based on the empirical correlation between pnictogen height (hPn) and superconducting gap behavior, in contrast to BaFe2(As(0.7)P(0.3))2 and Ba(Fe(0.65)Ru(0.35))2As2. We studied the low-lying electronic structure of Eu(Fe(0.79)Ru(0.21))2As2 with angle-resolved photoemission spectroscopy (ARPES). By photon energy dependence and polarization dependence measurements, we resolved the band structure in the three-dimensional momentum space and determined the orbital character of each band. In particular, we found that the dz2 -originated ζ band does not contribute spectral weight to the Fermi surface around Z, unlike BaFe2(As(0.7)P(0.3))2 and Ba(Fe(0.65)Ru(0.35))2As2. Since BaFe2(As(0.7)P(0.3))2 and Ba(Fe(0.65)Ru(0.35))2As2 are nodal superconductors and their hPn's are less than 1.33 Å, while the hPn of Eu(Fe(0.79)Ru(0.21))2As2 is larger than 1.33 Å, our results provide more evidence for a direct relationship between nodes, dz2 orbital character and hPn. Our results help to provide an understanding of the nodal superconductivity in iron-based superconductors.

Observation of possible topological in-gap surface states in the Kondo insulator SmB6 by photoemission.

SmB6, a well-known Kondo insulator, exhibits a transport anomaly at low temperature. This anomaly is usually attributed to states within the hybridization gap. Recent theoretical work and transport measurements suggest that these in-gap states could be ascribed to topological surface states, which would make SmB6 the first realization of topological Kondo insulator. Here by performing angle-resolved photoemission spectroscopy experiments, we directly observe several dispersive states within the hybridization gap of SmB6. These states show negligible kz dependence, which indicates their surface origin. Furthermore, we perform photoemission circular dichroism experiments, which suggest that the in-gap states possess chirality of the orbital angular momentum. These states vanish simultaneously with the hybridization gap at around 150 K. Together, these observations suggest the possible topological origin of the in-gap states.