Mutations Affecting Embryonic F-Actin Reorganization also Affect Separation of Nuclei from their Sisters and from the Cortex in Drosophila Cleavage Embryos

We showed in Drosophila that nuclear migration was reduced all through cleavage stages in embryos with any one of the maternal-effect mutations, gs(1)N441 and gs(1)N26 , in which F-actin reorganization in cleavage embryos is disordered. Moreover, we determined nuclear positions in embryos at cycle 1 and 2 in the wild type and two mutants, gs(1)N441 and gs(1)N26 , in order to test if the nuclear migration is regulated within a nuclear cycle. At cycle 1, there was no difference in nuclear position among the strains that we observed. At cycle 2 the two sister nuclei had already migrated posteriorly in the wild type. However, migration was not detectable at cycle 2 in the mutants. Besides, the two sister nuclei were less-separated from each other, and orientation of the two nuclei with regard to the anteroposterior axis was random, different from the wild type. These results support the hypothesis that F-actin is involved in the regulation to separate cleavage nuclei from each other and from the egg cortex. This regulation is apparently required for posteriorward nuclear migration, and for synchronous nuclear arrival in the whole egg cortex.     

The effects of phenolic glycosides from Betula platyphylla var. japonica on adipocyte differentiation and mature adipocyte metabolism

Betula platyphylla var. japonica (Betulaceae) has been used traditionally in Asian countries for the treatment of inflammatory diseases. A recent study has reported a phenolic compound, platyphylloside from B. platyphylla, that shows inhibition on adipocyte differentiation and induces lipolysis in 3T3-L1 cells. Based on this finding, we conducted phytochemical analysis of the EtOH extract of the bark of B. platyphylla var. japonica, which resulted in the isolation of phenolic glycosides (1–4). Treatment of the isolated compounds (1–4) during adipocyte differentiation of 3T3-L1 mouse adipocytes resulted in dose-dependent inhibition of adipogenesis. In mature adipocytes, arylbutanoid glycosides (2–4) induced lipolysis related genes HSL and ATGL, whereas catechin glycoside (1) had no effect. Additionally, arylbutanoid glycosides (2–4) also induced GLUT4 and adiponectin mRNA expression, indicating improvement in insulin signaling. This suggests that the isolates from B. platyphylla var. japonica exert benefial effects in regulation of adipocyte differentiation as well as adipocyte metabolism.     

Genetic influence on serum 25-hydroxyvitamin D concentration in Korean men: a cross-sectional study

Background

Hypovitaminosis D is prevalent worldwide. It is more prevalent in Eastern Asia region, including Korea. In addition to various environmental factors that influence serum 25-hydroxyvitamin D (25(OH)D) concentration, genetic influence also plays a significant role based on studies estimating the heritability of 25(OH)D in non-Asian populations. The objective of this study was to determine the genetic influence on serum 25(OH)D concentration in Korean men using the twin and family data.

Methods

A total of 1126 Korean male adult twins and family members from the Healthy Twin Study with serum 25(OH)D measurement were included in this cross-sectional study. Intraclass correlation coefficients (ICCs) and heritability were calculated by mixed linear regression analysis and quantitative genetic analysis after adjusting for environmental and lifestyle factors.

Results

Mean (±?standard deviation; SD) of serum 25(OH)D concentration was 15.34?±?6.18?ng/ml. The prevalence of vitamin D insufficiency was 19.8% and that of vitamin D deficiency was 77.9%. After adjusting for age, the highest ICC (0.61) was observed for monozygotic twin pairs while the lowest ICC (0.31) was found for father-son pairs. Age-adjusted heritability was estimated to be 58%. When physical activity, multivitamin intake and season of blood sampling were further considered, the ICC and heritability did not materially change. In the sensitivity analysis after excluding known multivitamin users, age-adjusted heritability was reduced to 44%.

Conclusions

In our study of Korean male twins and family members, heritability of 25(OH)D was moderately high. This supports the finding that genetic factors have significant influence on vitamin D status.

     

Structural insight into a novel indole prenyltransferase in hapalindole-type alkaloid biosynthesis

FamD1 is a novel CloQ/NphB-family indole prenyltransferase which involves in hapalindole-type alkaloid biosynthesis. Here the native FamD1 structure and three protein-ligand complexes are analyzed to investigate the molecular basis of substrate binding and catalysis. FamD1 adopts a typical ABBA architecture of aromatic prenyltransferase, in which the substrate-binding chamber is found in the central β-barrel. The indole-containing acceptor substrate is bound adjacent to the prenyl donor. Based on the complex structures, a catalytic mechanism of FamD1 is proposed. Functional implications on the sister enzyme FamD2 are also discussed.