Middle-Down and Chemical Proteomic Approaches to Reveal Histone H4 Modification Dynamics in Cell Cycle: Label-Free Semi-Quantification of Histone Tail Peptide Modifications Including Phosphorylation and Highly Sensitive Capture of Histone PTM Binding Proteins Using Photo-Reactive Crosslinkers

Mass spectrometric proteomics is an effective approach for identifying and quantifying histone post-translational modifications (PTMs) and their binding proteins, especially in the cases of methylation and acetylation. However, another vital PTM, phosphorylation, tends to be poorly quantified because it is easily lost and inefficiently ionized. In addition, PTM binding proteins for phosphorylation are sometimes resistant to identification because of their variable binding affinities. Here, we present our efforts to improve the sensitivity of detection of histone H4 tail peptide phosphorylated at serine 1 (H4S1ph) and our successful identification of an H4S1ph binder candidate by means of a chemical proteomics approach. Our nanoLC-MS/MS system permitted semi-quantitative label-free analysis of histone H4 PTM dynamics of cell cycle-synchronized HeLa S3 cells, including phosphorylation, methylation, and acetylation. We show that H4S1ph abundance on nascent histone H4 unmethylated at lysine 20 (H4K20me0) peaks from late S-phase to M-phase. We also attempted to characterize effects of phosphorylation at H4S1 on protein-protein interactions. Specially synthesized photoaffinity bait peptides specifically captured 14-3-3 proteins as novel H4S1ph binding partners, whose interaction was otherwise undetectable by conventional peptide pull-down experiments. This is the first report that analyzes dynamics of PTM pattern on the whole histone H4 tail during cell cycle and enables the identification of PTM binders with low affinities using high-resolution mass spectrometry and photo-affinity bait peptides.

Association between dental status and food diversity among older Japanese

OBJECTIVE

To investigate the relationship of dental status to food diversity among older Japanese.

DESIGN AND SETTING

A community-based cross-sectional study conducted in the town of Tosa, Kochi Prefecture, Japan.

METHODS

The study participants were 252 Japanese (84 men and 168 women, average age 81.2 years) and dentate participants were classified into three groups: 1-9 teeth, 10-19 teeth and 20 or more teeth. Food diversity was assessed as a validated measure of dietary quality using the 11-item Food Diversity Score Kyoto (FDSK-11), which evaluates frequency of consumption of 11 main food groups. Multivariable analysis of the differences in FDSK-11 score ranging from 0 to 11, with a higher score indicating greater food diversity, among the three dental status groups was conducted using general linear models. All the performed analyses were stratified by gender.

RESULTS

There was no association between dental status and food diversity score in models for men. In contrast, women with ≤ 9 teeth and with 10-19 teeth had significantly lower FDSK-11 scores than women with ≥ 20 teeth after adjusting for confounders (p < 0.001 and p = 0.009, respectively). Additionally, there was a trend toward lower scores for FDSK-11 with fewer teeth (p = 0.001).

CONCLUSION

A less varied diet, as indicated by low FDSK-11 score, was observed in female participants with fewer teeth. Tooth loss was associated with poor diet quality among older Japanese women.

2-Oxazoline formation for selective chemical labeling of 5-hydroxylysine

Hydroxylation of lysine, one of posttranslational modifications of proteins, generates 5-hydroxylysine (Koh) and plays a crucial role in regulating protein functions in cellular activity. We have developed a chemical labeling method of Koh. The 1,2-aminoalcohol moiety of Koh in synthetic peptide sequences was trapped by an alkyne-containing benzimidate to form a 2-oxazoline ring. An additional ammonia treatment process removed the undesirable amidine residue formed between benzimidate and lysine. During the ammonia treatment, the oxazoline residue formed at Koh mainly remained intact, and the ring opening to the amide form was observed for only part of oxazoline, indicating that the chemical labeling is amino acid selective. Azide-substituted biotin or fluorescent dye was attached to the peptide through Huisgen cycloaddition at Koh and converted into an alkyne-labeled oxazoline form. The Koh-labeling assay could provide a platform to enhance proteomic research of lysine hydroxylation.

Hybridization-sensitive fluorescent oligonucleotide probe conjugated with a bulky module for compartment-specific mRNA monitoring in a living cell

Live-cell RNA imaging at specific intracellular locations is technically limited because of the diffusive nature of small oligonucleotide probes. The bulky fluorescent light-up probes that possess streptavidin or gold nanoparticles at the end of oligonucleotides were designed and synthesized. The bulky probes allowed nucleus- and cytoplasm-selective monitoring of endogenous mRNAs through nuclear and cytoplasmic microinjection, respectively. Simultaneous use of bulky and unbulky probes conjugated with different fluorescent dyes enabled dual color imaging of mRNAs present in nucleus and cytoplasm. Furthermore, we observed that the fluorescence near the cell edge in a living HeLa cell traveled over time in coordination with the dynamic formation and deformation of the pseudopodial protrusions after lipofection of the bulky probes.

Short-interval multi-laser Thomson scattering measurements of hydrogen pellet ablation in LHD

Thomson scattering forms an important aspect of measuring the electron density and temperature profiles of plasmas. In this study, we demonstrate Thomson scattering measurements obtained over a short interval (<1 ms) by using an event triggering system with a multi-laser configuration. We attempt to use our system to obtain the electron temperature and density profiles before and immediately after pellet injection into the large helical device. The obtained profiles exhibit dramatic changes after pellet injection as per our shot-by-shot measurements. We believe that this measurement technique will contribute towards a better understanding of the physics of the pellet deposition.

Relationship of vitamin D levels to blood pressure in a biethnic population

BACKGROUND AND AIMS

Accumulating epidemiological and clinical studies have suggested that vitamin D insufficiency may be associated with hypertension. Blacks tend to have lower vitamin D levels than Whites, but it is unclear whether this difference explains the higher blood pressure (BP) observed in Blacks in a population with healthy lifestyle practices.

METHODS AND RESULTS

We examined cross-sectional data in the Adventist Health Study-2 (AHS-2), a cohort of non-smoking, mostly non-drinking men and women following a range of diets from vegan to non-vegetarian. Each participant provided dietary, demographic, lifestyle and medical history data. Measurements of weight, height, waist circumference, percent body fat and blood pressure and fasting blood samples were obtained from a randomly selected non-diabetic sample of 284 Blacks and 284 Whites aged 30-95 years. Multiple regression analyses were used to assess independent relationships between blood pressure and 25(OH)D levels. Levels of 25(OH)D were inversely associated with systolic BP in Whites after control for age, gender, BMI, and use of BP-lowering medications (β-coefficient -0.23 [95% CI, -0.43, -0.03; p = 0.02]). This relationship was not seen in Blacks (β-coefficient 0.08 [95% CI, -0.14, 0.30; p = 0.4]). Results were similar when controlling for waist circumference or percentage body fat instead of BMI. No relationship between serum 25(OH)D and diastolic BP was seen.

CONCLUSION

Systolic BP is inversely associated with 25(OH)D levels in Whites but not in Blacks. Vitamin D may not be a major contributor to the White-Black differential in BP.

Imaging spectroscopy diagnosis of internal electron temperature and density distributions of plasma cloud surrounding hydrogen pellet in the Large Helical Device

To investigate the behavior of hydrogen pellet ablation, a novel method of high-speed imaging spectroscopy has been used in the Large Helical Device (LHD) for identifying the internal distribution of the electron density and temperature of the plasma cloud surrounding the pellet. This spectroscopic system consists of a five-branch fiberscope and a fast camera, with each objective lens having a different narrow-band optical filter for the hydrogen Balmer lines and the background continuum radiation. The electron density and temperature in the plasma cloud are obtained, with a spatial resolution of about 6 mm and a temporal resolution of 5 × 10(-5) s, from the intensity ratio measured through these filters. To verify the imaging, the average electron density and temperature also have been measured from the total emission by using a photodiode, showing that both density and temperature increase with time during the pellet ablation. The electron density distribution ranging from 10(22) to 10(24) m(-3) and the temperature distribution around 1 eV have been observed via imaging. The electron density and temperature of a 0.1 m plasma cloud are distributed along the magnetic field lines and a significant electron pressure forms in the plasma cloud for typical experimental conditions of the LHD.

Eating alone among community-dwelling Japanese elderly: association with depression and food diversity

Eating alone is an emerging social concern these days along with the background of serious aging population growth and increasing number of single-dwellers in Japan. However, little study is focused eating alone and its relation to the health status of community-dwelling elderly.

OBJECTIVES

To clarify the relations between eating alone and geriatric functions such as depression, quantitative subjective quality of life (QOL), activities of daily living (ADL) and dietary status of community-dwelling Japanese elderly.

DESIGN

A cross-sectional study.

SETTINGS

Tosa town, one of the "super-aged" towns in Japan.

PARTICIPANTS

The study population consisted of 856 community-dwelling elderly aged ≥65 living in Tosa town.

MEASUREMENTS

Eating alone and living arrangement was defined by the questionnaire. Geriatric functions were assessed by measuring activities of daily living (ADL), depressive symptom using 15-item geriatric depression scale (GDS-15), and quality of life (QOL). Food diversity was investigated as a measure of dietary quality using 11-item Food Diversity Score Kyoto (FDSK-11). Body mass index (BMI) was calculated using height and body weight during a medical assessment.

RESULTS

The proportion of the elderly who usually eat alone was 33.2% in this study population. Even among 697 elderly subjects who live with others, 136 persons (19.5%) ate alone. The participants who ate alone were significantly depressed according to the assessment using GDS-15 score (5.7±4.3 vs. 4.4±3.8, P<0.001). Those who ate alone have lower scores of QOL items than those who ate with others (Subjective sense of health: 52.5±21.9 vs. 55.7±20.2 P=0.035, Relationship with family: 74.1±23.5 vs. 78.9±18.6 P<0.001, Subjective happiness: 58.5±22.7 vs. 62.2±21.1 P=0.019). A significant close association was found between eating alone and lower food diversity (FDSK-11 score 9.9±1.3 vs. 10.2±1.3, P=0.002). BMI was lower in the elderly subjects who ate alone than those with others. By the multivariate analysis, depression was independently associated with eating alone in the logistic regression model adjusted for age, sex, BMI and food diversity as confounding factors (OR: 1.42, CI: 1.00-2.11, P=0.043). Food diversity was also significantly associated even after the adjustment of these confounding factors.

CONCLUSION

Eating alone is an important issue related to depression and QOL as well as dietary status of community-dwellingl elderly in Japan. This study shows the simple and inexpensive way "eating together" may contribute to improve depressive mood of elderly persons, with a strong message that supports of family, friends and neighbors are very important.

Design and performance of a punch mechanism based pellet injector for alternative injection in the large helical device

A low speed single barrel pellet injector, using a mechanical punch device has been developed for alternative injection in the large helical device. A pellet is injected by the combined operation of a mechanical punch and a pneumatic propellant system. The pellet shape is cylindrical, 3 mm in diameter and 3 mm in length. Using this technique the speed of the pellet can be controlled flexibly in the range of 100-450 m/s, and a higher speed can be feasible for a higher gas pressure. The injector is equipped with a guide tube selector to direct the pellet to different injection locations. Pellets are exposed to several curved parts with the curvature radii R(c) = 0.8 and 0.3 m when they are transferred in guided tubes to the respective injection locations. Pellet speed variation with pressure at different pellet formation temperatures has been observed. Pellet intactness tests through these guide tubes show a variation in the intact speed limit over a range of pellet formation temperatures from 6.5 to 9.8 K. Pellet speed reduction of less than 6% has been observed after the pellet moves through the curved guide tubes.

Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma

Reversed-shear Alfvén eigenmodes were observed for the first time in a helical plasma having negative q₀'' (the curvature of the safety factor q at the zero shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calculated by ideal MHD theory are consistent with the experimental data. The frequency sweeping is mainly determined by the effects of energetic ions and the bulk pressure gradient. Coupling of reversed-shear Alfvén eigenmodes with energetic ion driven geodesic acoustic modes generates a multitude of frequency-sweeping modes.