Social capital and mental health in Japan: a multilevel analysis

Background

A national cross-sectional survey was conducted in Japan. This is because the growing recognition of the social determinants of health has stimulated research on social capital and mental health. In recent years, systematic reviews have found that social capital may be a useful factor in the prevention of mental illness. Despite these studies, evidence on the association between social capital and mental health is limited as there have been few empirical discussions that adopt a multilevel framework to assess whether social capital at the ecological level is associated with individual mental health. The aim of this study was to use the multilevel approach to investigate the association between neighborhood social capital and mental health after taking into account potential individual confounders.

Methodology/Principal Findings

We conducted a multilevel analysis on 5,956 individuals nested within 199 neighborhoods. The outcome variable of self-reported mental health was measured by the one dimension of SF-36 and was summed to calculate a score ranging from 0 to 100. This study showed that high levels of cognitive social capital, measured by trust (regression coefficient = 9.56), and high levels of structural social capital, measured by membership in sports, recreation, hobby, or cultural groups (regression coefficient = 8.72), were associated with better mental health after adjusting for age, sex, household income, and educational attainment. Furthermore, after adjusting for social capital perceptions at the individual level, we found that the association between social capital and mental health also remained.

Conclusions/Significance

Our findings suggest that both cognitive and structural social capital at the ecological level may influence mental health, even after adjusting for individual potential confounders including social capital perceptions. Promoting social capital may contribute to enhancing the mental health of the Japanese.     

Yeast autophagosomes: de novo formation of a membrane structure

Autophagy - the degradation of organelles and cytoplasmic material - occurs through dynamic rearrangements of cellular membrane structures. Following the induction of autophagy, newly formed autophagosomes transfer cytosolic materials to the lysosome or vacuole for degradation. The autophagosome is an organelle destined for degradation, suggesting that the membrane structure is formed de novo many times. The autophagosome is formed through the nucleation, assembly and elongation of membrane structures. The concerted action of several Apg/Aut/Cvt proteins around a characteristic subcellular structure (the preautophagosomal structure) is the key to understanding this novel type of membrane-formation process.     

Assay of biological thiols by a combination of high-performance liquid chromatography and postcolumn reaction with 6,6'-dithiodinicotinic acid

A simple and rapid method for the determination of nanomole levels of biological thiols is described. The analysis is based on the combination of reverse-phase high-performance liquid chromatography with a postcolumn reaction with 6,6'-dithiodinicotinic acid. Thiols, including cysteine, cysteamine, thiolhistidine, homocysteine, glutathione, penicillamine, ergothioneine, and thiouracil were separated by eluting with 33 mM KH2PO4 at pH 2.2. Glutathione, cysteine, cysteamine, homocysteine, and penicillamine were quantitatively determined with detection limits of 0.1 nmol, while the quantitative detection of thiolhistidine, ergothioneine, and thiouracil was not successful. The method was applied to the assay of glutathione in human erythrocytes and Escherichia coli.     

Inhibition of cell growth by bafilomycin A1, a selective inhibitor of vacuolar H+-ATPase

Summary Bafilomycin A₁, a potent selective inhibitor of vacuolar H⁺-ATPase, inhibited the growth of a variety of cultured cells dose-dependently, including golden hamster embryo and NIH-3T3 fibroblasts, whether or not they were transformed, and PC12 and HeLa cells. The concentration of bafilomycin A₁ for 50% inhibition of cell growth ranged from 10 to 50 nM. The dose response was nearly parallel with that of the bafilomycin A₁-induced lysosomal pH increase. The degree of pH increase for growth inhibition produced by bafilomycin A₁ was similar to that produced by NH₄Cl in which little difference was recognized in effect among cell types.     

The receptor-like kinase SOL2 mediates CLE signaling in Arabidopsis

Arabidopsis sol2 mutants showed CLV3 peptide resistance. Twenty-six synthetic CLE peptides were examined in the clv1, clv2 and sol2 mutants. sol2 showed different levels of resistance to the various peptides, and the spectrum of peptide resistance was quite similar to that of clv2. SOL2 encoded a receptor-like kinase protein which is identical to CORYNE (CRN). GeneChip analysis revealed that the expression of several genes was altered in the sol2 root tip. Here, we suggest that SOL2, together with CLV2, plays an important role in the regulation of root meristem development through the CLE signaling pathway.     

Characterization of 'Candidatus Clavochlamydia salmonicola': an intracellular bacterium infecting salmonid fish

The phylum Chlamydiae contains obligate intracellular bacteria, several of which cause disease in their hosts. Morphological studies have suggested that this group of bacteria may be pathogens of fish, causing cysts in epithelial tissue – epitheliocystis. Recently, the first genetic evidence of a chlamydial aetiology of this disease in seawater reared Atlantic salmon from Norway and Ireland was presented, and the agent was given the name ' Candidatus Piscichlamydia salmonis'. In this article we present molecular evidence for the existence of a novel Chlamydiae that also may cause epitheliocystis in Norwegian salmonids. This novel Chlamydiae has been found in salmonid fish from freshwater, and based on its partial 16S rRNA gene, it may constitute a third genus in the family Chlamydiaceae , or a closely related sister family. By using whole-mount RNA–RNA hybridization we demonstrate how infected cells are distributed in a patchy manner on a gill arch. The morphology of the novel Chlamydiae includes the characteristic head-and-tail cells that have been described earlier from salmonid fish suffering from epitheliocystis. We propose the name ' Candidatus Clavochlamydia salmonicola' for this agent of epitheliocystis in freshwater salmonids.     

Studies of cargo delivery to the vacuole mediated by autophagosomes in Saccharomyces cerevisiae

In the yeast Saccharomyces cerevisiae, aminopeptidase I (API), a vacuolar hydrolase, is selectively transported to the vacuole via the autophagosome. API forms a cytosol to vacuole targeting (Cvt) complex in the cytoplasm. The complex is engulfed by the autophagosome under starvation conditions. In this study, the Cvt complex is visualized as a dot in the cytoplasm by fluorescence microscopy with API-GFP. The Cvt complex associates with the preautophagosomal structure (PAS), which plays a central role in autophagosome formation. In a Deltacvt19 mutant, which is specifically defective in API transport, but not in autophagy, the Cvt complex forms normally but never associates with the PAS. This indicates that Cvt19p mediates association between the Cvt complex and the PAS.     

ESR Studies on Lipid-protein Interaction in Gluten

The interaction of protein with lipid in wheat gluten has been studied by electron spin resonance (ESR). The gluten in the flour suspension was spin-labeled with a fatty acid spin label (N-oxyl-4,4'-dimethyloxazolidine derivative of 5-ketostearic acid) and washed out from the flour. The ESR spectra of the spin label incorporated in gluten exhibited clearly separated parallel and perpendicular hyperfine splittings. The orientation of the gluten lipid and its fluidity showed temperature dependence. Phase transition was observed at 25°C. Compared with gluten, vesicles of the lipids extracted from flour were found to be in a less oriented, highly fluid state, and with much lower activation energy for rotational viscosity, while the reconstituted gluten, which was prepared by mixing purified gluten protein and the extracted lipids, had a lipid environment similar to that of gluten. The results indicate that the lipid was immobilized in the gluten matrix by strong interaction with protein.     

‘Cand. Actinochlamydia clariae’ gen. nov., sp. nov., a Unique Intracellular Bacterium Causing Epitheliocystis in Catfish (Clarias gariepinus) in Uganda

Background and Objectives

Epitheliocystis, caused by bacteria infecting gill epithelial cells in fish, is common among a large range of fish species in both fresh- and seawater. The aquaculture industry considers epitheliocystis an important problem. It affects the welfare of the fish and the resulting gill disease may lead to mortalities. In a culture facility in Kampala, Uganda, juveniles of the African sharptooth catfish (Clarias gariepinus) was observed swimming in the surface, sometimes belly up, showing signs of respiratory problems. Histological examination of gill tissues from this fish revealed large amounts of epitheliocysts, and also presence of a few Ichthyobodo sp. and Trichodina sp.

Methods and Results

Sequencing of the epitheliocystis bacterium 16S rRNA gene shows 86.3% similarity with Candidatus Piscichlamydia salmonis causing epitheliocystis in Atlantic salmon (Salmo salar). Transmission electron microscopy showed that the morphology of the developmental stages of the bacterium is similar to that of members of the family Chlamydiaceae. The similarity of the bacterium rRNA gene sequences compared with other chlamydia-like bacteria ranged between 80.5% and 86.3%. Inclusions containing this new bacterium have tubules/channels (termed actinae) that are radiating from the inclusion membrane and opening on the cell surface or in neighbouring cells.

Conclusions

Radiation of tubules/channels (actinae) from the inclusion membrane has never been described in any of the other members of Chlamydiales. It seems to be a completely new character and an apomorphy. We propose the name Candidatus Actinochlamydia clariae gen. nov., sp. nov. (Actinochlamydiaceae fam. nov., order Chlamydiales, phylum Chlamydiae) for this new agent causing epitheliocystis in African sharptooth catfish.