Contrasting patterns of genetic structure and phylogeography in the marine agarophytes Gelidiophycus divaricatus and G. freshwateri (Gelidiales,Rhodophyta) from East Asia

The evolutionary and population demographic history of marine red algae in East Asia is poorly understood. Here, we reconstructed the phylogeographies of two upper intertidal species endemic to East Asia, Gelidiophycus divaricatus and G. freshwateri. Phylogenetic and phylogeographic inferences of 393 mitochondrial cox1, 128 plastid rbcL, and 342 nuclear ITS2 sequences were complemented with ecological niche models. Gelidiophycus divaricatus, a southern species adapted to warm water, is characterized by a high genetic diversity and a strong geographical population structure, characteristic of stable population sizes and sudden reduction to recent expansion. In contrast, G. freshwateri, a northern species adapted to cold temperate conditions, is genetically relatively homogeneous with a shallow population structure resulting from steady population growth and recent equilibrium. The overlap zone of the two species roughly matches summer and winter isotherms, indicating that surface seawater temperature is a key feature influencing species range. Unidirectional genetic introgression was detected at two sites on Jeju Island where G. divaricatus was rare while G. freshwateri was common, suggesting the occurrence of asymmetric natural hybrids, a rarely reported event for rhodophytes. Our results illustrate that Quaternary climate oscillations have left strong imprints on the current day genetic structure and highlight the importance of seawater temperature and sea level change in driving speciation in upper intertidal seaweed species.     

Effect of circadian rhythm type on serum lipid levels in shift workers: A 5-year cohort study

We investigated how differences in circadian rhythm type affect the health of workers engaged in shift work. Employees, who were newly hired in a steel company between 2007 and 2011, received the Morningness–Eveningness Questionnaire (MEQ) survey. The target participants were 153 male shift workers who were not being treated with any antihyperlipidemic drugs and underwent periodic physical examinations including blood tests at least twice. According to the score of the MEQ at the time of joining the company, we classified the subjects into five types. Longitudinal changes in serum lipid level were estimated among the circadian rhythm types adjusted for age, BMI, and other covariates using a linear mixed model. The regression coefficient of total cholesterol level in the “definitely and moderately morning” group was ?17.83 (95% confidence interval (CI): ?33.42 to ?2.23), and in the “intermediate ‘group’ was ?16.84 [95% CI: ?30.40 to ?3.28], compared to the moderate evening type.” The total cholesterol level was higher in the moderately evening type than in any of the other groups. Between the Morningness–Eveningness (ME) type and Low-density lipoprotein (LDL) cholesterol levels, compared with the “moderately evening type” group, the regression coefficient in the “intermediate type” group was ?16.08 (95% CI: ?28.79 to ?3.37), and in the “definitely and moderately morning type” group was ?17.50 [95% CI: ?32.11 to ?2.88]. The “moderately evening type” group had a higher LDL cholesterol level than any of the other groups. Evening-type circadian rhythm type shift workers are more prone to elevated serum lipid levels.     

Activation of human T lymphocytes by ganglioside-containing liposomes

We investigated the in vitro stimulatory effect of ganglioside (G_M3, G_D1a, G_D1b, G_T1b, or G_Q1b)-containing liposomes on human immune cells. The effect of ganglioside-containing liposomes on the concentration of cytoplasmic free calcium ions ([Ca²⁺]₁) in human immunocytes was examined using the confocal laser fluorescence microscopic method. The G_D1a- and G_T1b-containing liposomes significantly increased [Ca²⁺]₁ of human T lymphocytes compared with the G_M3-, G_D1b- and G_Q1b-containing ones. The response of CD8⁺ and CD4⁺ cells was significantly higher than that of CD20⁺ cells. Our results show that the increase in [Ca²⁺]_i may be caused by not the number of sialic acids contained in the gangliosides but the conformation of the sialic acid moiety to protrude exteriorly from the liposomal membrane surface, and that a sort of receptor recognizing the sialic acid moiety exists on human T lymphocytes (both CD8⁺ and CD4⁺ cells), which may be involved in the activation of the cells. The present results are almost the same as those obtained for the rat T lymphocyte system previously reported. This clearly confirms that a sort of ganglioside surely stimulates T lymphocytes directly, which is not species-specific but conserved in humans and rats among animal species.     

Thermodynamic analyses of calcium binding to troponin C, calmodulin and parvalbumins by using microcalorimetry

Results of microcalorimetric titrations of calcium-binding proteins with calcium or magnesium have been reviewed and evaluated. Results were analyzed mostly in terms of heat capacity changes, which is most closely related to the structural changes of the molecule on metal binding. Two high-affinity sites of rabbit skeletal troponin C are distinguishable in terms of their affinity to calcium and associated enthalpy changes. Heat capacity changes on calcium binding to one of the two high-affinity sites is negative and is in the range ascribed to the ligand binding. In contrast, that to the other of the high-affinity sites is large and positive, indicating that a substantial area of hydrophobic groups become exposed to the solvent. In frog skeletal troponin C, the anomalous positive heat capacity changes occur in one of the low-affinity calcium-specific sites, so that this may be involved in the regulation of contraction. Unlike skeletal troponin C, both of the two high-affinity sites of cardiac troponin C show negative heat capacity changes. In calmodulin, heat capacity changes are positive but small, indicating that calcium binding may induce clustering of the hydrophobic residues on the surface of the molecule. In parvalbumins, heat capacity changes are negative, characteristic of most ligand binding.     

Growing and differentiating characterization of aortic smooth muscle cell line, p53LMAC01 obtained from p53 knock out mice

Recently we have established an aortic smooth muscle cell line, p53LMAC01 obtained from p53 knockout mice. This cell line showed some differentiated properties which were accelerated by 5-azacytidine treatment [1]. In this study, further characterization of p53LMAC01 cell line was investigated according to cell growth and differentiation, and especially focused into the changes of cell feature, actin filaments' formation, and changes of intracellular calcium concentrations to sympathetic nerve transmitter, norepinephrine. While the cell feature was changed from flattened shape to extended form during 4 days, actin filaments were developing, arranging in parallel to longitudinal direction, and gathering under the surface membrane. In 11 days many cells died and detached from substrate, while actin filaments became poor except for the surface membrane in the remained cells. Appearance of calcium response to noradrenalin needed several days after passage as well as a morphological change of the cells for the extended form and development of actin filaments. The calcium response was maintained on 11 days, which coincided with the result that the cells hold actin filaments under the surface membrane. These results suggest that p53LMAC01 cell line maintains several differentiated characters of adult smooth muscle cell and that their expression needs several days after passage.     

Brap2 functions as a cytoplasmic retention protein for p21 during monocyte differentiation

The cell cycle inhibitor p21 plays an important role in monocytic cell differentiation, during which it translocates from the nucleus to cytoplasm. This process involves the negative regulation of the p21 nuclear localization signal (NLS). Here, we sought to determine the relationship between the cytoplasmic translocation of p21 and another molecule, Brap2, a cytoplasmic protein which binds the NLS of BRCA1 and was recently reported to inactivate KSR in the Ras-activating signal pathway under the name of IMP. We report that p21 and Brap2 directly interact, both in vitro and in vivo, in a manner requiring the NLS of p21 and the C-terminal portion of Brap2. When it is cotransfected with Brap2, p21 is expressed in the cytoplasm. Monocytic differentiation of the promyelomonocytic cell lines U937 and HL60 is associated with the upregulation of Brap2 expression concomitantly with the upregulation and cytoplasmic relocalization of p21. Our results underscore the role played by Brap2 in the process of cytoplasmic translocation of p21 during monocyte differentiation.     

Sex- and lineage-specific inheritance of depression-like behavior in the rat

The Wistar–Kyoto (WKY) rat exhibits physiological and behavioral similarities to endophenotypes of human depression. In the forced swim test (FST), a well-characterized antidepressant-reversible test for behavioral despair in rodents, WKYs express characteristics of behavioral despair; increased immobility, and decreased climbing. To map genetic loci linked to behavior in the FST, we conducted a quantitative trait loci (QTL) analysis of the segregating F2 generation of a WKY × Fisher 344 (F344) reciprocal intercross. Using linear-model-based genome scans to include covariate (sex or lineage)-by-QTL interaction effects, four significant QTL influencing climbing behavior were identified. In addition, we identified three, seven, and two suggestive QTL for climbing, immobility, and swimming, respectively. One of these loci was pleiotropic, affecting both immobility and climbing. As found in human linkage studies, several of these QTL showed sex- and/or lineage-dependent effects. A simultaneous search strategy identified three epistatic locus pairs for climbing. Multiple regression analysis was employed to characterize the joint contributions of these QTL and to clarify the sex- and lineage-dependent effects. As expected for complex traits, FST behavior is influenced by multiple QTL of small effect, each contributing 5%–10%, accounting for a total 10%–30% of the phenotypic variance. A number of loci mapped in this study share overlapping candidate regions with previously identified emotionality QTL in mice as well as with susceptibility loci recognized by linkage or genome scan analyses for major depression or bipolar disorder in humans. The presence of these loci across species suggests that these QTL may represent universal genetic factors contributing to mood disorders.