The gut microbiota and coronary artery calcification in Japanese men.

BACKGROUND: The gut microbiota differs between patients with coronary artery disease (CAD) and healthy controls; however, it currently remains unclear whether these differences exist prior to the onset of CAD. We herein investigated the gut microbiota associated with subclinical coronary artery calcification (CAC) in a Japanese population. METHODS: A total of 663 Japanese men were enrolled in this cross-sectional study. Computed tomography and gut microbiology tests were performed, and CAC scores were calculated using the Agatston method. Participants were categorized into 4 groups based on their CAC scores: CAC = 0, 0

Relationship Between Hemoglobin Concentration and Cardiovascular Disease Mortality in a 25-Year Follow-up Study of a Japanese General Population　- NIPPON DATA90.

BACKGROUND: Deviations of hemoglobin from normal levels may be a factor in cardiovascular disease (CVD) risk; however, conclusive evidence is lacking. In addition, preclinical conditions may influence hemoglobin concentrations, but studies focusing on reverse causation are limited. Thus, we examined the relationship between hemoglobin concentrations and CVD mortality risk, considering reverse causation.Methods and Results: In a prospective cohort representative of the general Japanese population (1990-2015), we studied 7,217 individuals (mean age 52.3 years; 4,219 women) without clinical CVD at baseline. Participants were categorized into sex-specific hemoglobin quintiles (Q1-Q5) and data were analyzed using the Cox proportional hazards model adjusted for possible confounders. During a 25-year follow-up, 272 men and 334 women died from CVD. Adjusted hazard ratios for CVD mortality across sex-specific quintiles, using Q3 as the reference, were significantly higher for Q1 (1.40; 95% confidence interval [CI] 1.08-1.82) and Q5 (1.49; 95% CI 1.14-1.96), and remained significant after excluding deaths within the first 5 years of follow-up to consider reverse causation (1.35 [95% CI 1.02-1.79] and 1.45 [95% CI 1.09-1.94], respectively). A similar U-shaped association was seen between transferrin saturation levels and CVD mortality, but after excluding deaths within the first 5 years the association was significant only for Q1. CONCLUSIONS: Low and high hemoglobin concentrations were associated with an increased risk of CVD mortality.

NMR characterization of the structure of the intrinsically disordered region of human origin recognition complex subunit 1, hORC1, and of its interaction with G-quadruplex DNAs.

Human origin recognition complex (hORC) binds to the DNA replication origin and then initiates DNA replication. However, hORC does not exhibit DNA sequence-specificity and how hORC recognizes the replication origin on genomic DNA remains elusive. Previously, we found that hORC recognizes G-quadruplex structures potentially formed near the replication origin. Then, we showed that hORC subunit 1 (hORC1) preferentially binds to G-quadruplex DNAs using a hORC1 construct comprising residues 413 to 511 (hORC1413-511). Here, we investigate the structural characteristics of hORC1413-511 in its free and complex forms with G-quadruplex DNAs. Circular dichroism and nuclear magnetic resonance (NMR) spectroscopic studies indicated that hORC1413-511 is disordered except for a short α-helical region in both the free and complex forms. NMR chemical shift perturbation (CSP) analysis suggested that basic residues, arginines and lysines, and polar residues, serines and threonines, are involved in the G-quadruplex DNA binding. Then, this was confirmed by mutation analysis. Interestingly, CSP analysis indicated that hORC1413-511 binds to both parallel- and (3 + 1)-type G-quadruplex DNAs using the same residues, and thereby in the same manner. Our study suggests that hORC1 uses its intrinsically disordered G-quadruplex binding region to recognize parallel-type and (3 + 1)-type G-quadruplex structures at replication origin.

Dietary Carbohydrate and Fat Intakes and Risk of Mortality in the Japanese Population: the Japan Multi-Institutional Collaborative Cohort Study.

BACKGROUND: Previous cohort studies have yielded contradictory findings regarding the associations of dietary carbohydrate and fat intakes with risks of mortality. OBJECTIVES: We examined long-term associations of carbohydrate and fat intakes with mortality. METHODS: In this cohort study, 34,893 men and 46,440 women aged 35-69 y (mean body mass index of 23.7 and 22.2 kg/m2, respectively) were followed up from the baseline survey (2004-2014) to the end of 2017 or 2018. Intakes of carbohydrate, fat, and total energy were estimated using a food frequency questionnaire. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for all-cause and cause-specific mortality according to percentage of energy intakes of carbohydrate and fat. RESULTS: During a mean 8.9-y follow-up, we identified 2783 deaths (1838 men and 945 women). Compared with men who consumed 50% to <55% of energy from carbohydrate, those who consumed <40% carbohydrate energy experienced a significantly higher risk of all-cause mortality (the multivariable-adjusted HR: 1.59; 95% CI: 1.19-2.12; P-trend = 0.002). Among women with 5 y or longer of follow-up, women with high-carbohydrate intake recorded a higher risk of all-cause mortality; the multivariable-adjusted HR (95% CI) was 1.71 (0.93-3.13) for ≥65% of energy from carbohydrate compared with that for 50% to <55% (P-trend = 0.005). Men with high fat intake had a higher risk of cancer-related mortality; the multivariable-adjusted HR (95% CI) for ≥35% was 1.79 (1.11-2.90) compared with that for 20% to <25%. Fat intake was marginally inversely associated with risk of all-cause and cancer-related mortality in women (P-trend = 0.054 and 0.058, respectively). CONCLUSIONS: An unfavorable association with mortality is observed for low-carbohydrate intake in men and for high-carbohydrate intake in women. High fat intake can be associated with a lower mortality risk in women among Japanese adults with a relatively high-carbohydrate intake.

Association between proprotein convertase subtilisin/kexin type 9 and subclinical cerebrovascular disease in the community.

BACKGROUND AND PURPOSE: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a new target for reducing low-density lipoprotein cholesterol and incident cardiovascular disease, including stroke. However, the clinical relevance of circulating PCSK9 levels has been poorly elucidated in the general population, particularly in association with subclinical cerebrovascular disease including cerebral small vessel disease (CSVD) and intracranial artery stenosis (ICAS). METHODS: In community-dwelling Japanese men (n = 526) aged 46-82 years without a history of cardiovascular disease, the associations of serum PCSK9 levels with the prevalence of CSVD and ICAS were assessed using magnetic resonance imaging. CSVD included lacunar infarction, deep and subcortical white matter hyperintensity, periventricular hyperintensity and cerebral microbleeds. RESULTS: The median (interquartile range) age at baseline and serum PCSK9 levels were 69 (63-74) years and 240 (205-291) ng/ml, respectively. After adjusting for traditional cardiovascular risk factors including low-density lipoprotein cholesterol, multivariable Poisson regression with robust error variance revealed a significant association between PCSK9 levels (per 1 SD) and ICAS (relative risks 1.18, 95% confidence interval 1.02-1.37). Multivariable ordinal logistic regression for ICAS, with stenosis graded as mild (<50%) or moderate-severe (≥50%), revealed a similar association (common odds ratio 1.31, 95% confidence interval 1.04-1.64). However, no significant association was observed between serum PCSK9 levels and CSVD. CONCLUSIONS: Higher circulating PCSK9 levels were independently associated with an ICAS prevalence but not with CSVD prevalence. The quantification of circulating PCSK9 levels may help to identify individuals at high risk for cerebrovascular disease in the general population.

Enzymatic degradation of glucosaminoglucan and cellulase resistance of cellulose nanofiber coated with glucosaminoglucan.

AIMS: Enzymatic degradation of ß-1,4-linked glucose and glucosamine (glucosaminoglucan, GG), which is prepared from Thiothrix nivea and can act as a cellulose-aminating agent with a strong affinity to cellulose, was attempted. METHODS AND RESULTS: A chitosanase-secreting fungal strain was isolated as a GG-degrading microbe. GG was found to be degraded by not only chitosanases but also cellulases. Based on nuclear magnetic resonance spectroscopy, both enzymes were found to produce GlcN-Glc from GG. The cellulases also produced GlcN-Glc-GlcN-Glc as an additional final digest. Furthermore, aminated (GG-coated) cellulose nanofibers exhibited cellulase resistance. The flexibility of GG adsorbed onto a cellulose crystal was almost identical to that of cellulose, as estimated via the molecular dynamics calculations. CONCLUSIONS: The chitosanase and cellulase hydrolyzed the ß-1,4-linkage from Glc to GlcN and were expected to recognize the tetramer and hexamer units of GG depending on their final products. The cellulose nanofibers acquired cellulase resistance via amination with GG, probably because of the lower activity of cellulase to GG than cellulose.

Relationship of Higher-level Functional Capacity With Long-term Mortality in Japanese Older People: NIPPON DATA90.

BACKGROUND: Basic and instrumental activities of daily living (BADL and IADL, respectively) are known predictors of mortality. However, the relationship between higher-level functional capacity (HLFC) and mortality and related sex differences have rarely been investigated. METHODS: A prospective population-based cohort study was conducted in 1,824 older residents (≥65 years) with independent BADL from 300 randomly selected areas in Japan from 1995, and the participants were followed up until 2010. Using the Cox proportional hazards model, the relationship between HLFC and mortality risk was investigated, with adjustment for possible confounders. HLFC was assessed using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Baseline data were collected using a questionnaire or by home-visit interviews. RESULTS: During an average 12.2-year follow-up, all-cause death was observed in 836 (45.8%) participants. Impaired HLFC was significantly associated with mortality (hazard ratio [HR] 1.37; 95% confidence interval [CI], 1.13-1.65). Lower social role was significantly associated with higher mortality risk in men (HR 1.38; 95% CI, 1.13-1.68). Lower IADL and intellectual activity were significantly associated with higher mortality risk in women (HR 1.50; 95% CI, 1.15-1.95 and HR 1.46; 95% CI, 1.19-1.79, respectively). The relationship between HLFC and mortality risk showed a similar tendency among cardiovascular diseases, stroke, cancer, and pneumonia. CONCLUSION: Impaired HLFC was associated with a high risk of all-cause mortality among community-dwelling older people with independent BADL. In particular, social role in men and IADL and intellectual activity in women were associated with long-term mortality risk.

Impact of Resting Heart Rate on Cardiovascular Mortality According to Serum Albumin Levels in a 24-year Follow-up Study on a General Japanese Population: NIPPON DATA80.

BACKGROUND: Elevated resting heart rate (RHR) is associated with an increased risk of cardiovascular disease (CVD) and all-cause mortality. However, the findings of cohort studies differed. Thus, the impact of RHR on CVD mortality might be different according to the background of the population. Therefore, we examined the relationship of RHR and CVD mortality according to serum albumin (ALB) levels in a Japanese general population. METHODS: In total, 8,363 individuals without a history of CVD were followed for 24.0 years. The participants were divided into four groups according to the quartiles of RHR (Q1-Q4), and they were further classified into the high and low ALB groups based on a median value of 44 g/L. We estimated the multivariable-adjusted hazard ratios (HRs) of CVD mortality in each RHR group based on ALB levels, and the interaction between RHR and ALB groups on CVD mortality was evaluated. RESULTS: We found no significant association between RHR and CVD mortality. However, the Q4 of RHR was significantly associated with an increased risk for CVD mortality (HR 1.27; 95% confidence interval [CI], 1.02-1.57) in participants with a low ALB level. Meanwhile, the Q4 of RHR was significantly correlated with a decreased risk for CVD morality in those with a high ALB level (HR 0.61; 95% CI, 0.47-0.79) after adjusting for covariates. A significant interaction between RHR and ALB for CVD mortality was shown (P < 0.001). CONCLUSION: The impact of RHR on CVD mortality differed according to ALB levels in a general Japanese population.

Smoking is associated with impaired long-term quality of life in elderly people: a 22-year cohort study in NIPPON-DATA 90.

BACKGROUND: Whether smoking is associated with worse quality of life (QoL) or not is relatively controversial. Current study is to investigate relationship between smoking and subjective QoL in a long cohort study. METHODS: NIPPON DATA 90 project collected 8383 community residents in 300 randomly selected areas as baseline data in 1990, and 4 follow-up QOL surveys and mortality statistics were performed. We conducted multinomial logistic regression analysis to compare past smoker and current smoker to never smoker, of which impaired QOL and mortality as outcomes. RESULTS: In 4 follow-ups, QOL data was collected from 2035, 2252, 2522 and 3280 participants, in 1995, 2000, 2005, 2012, respectively. In 1995 follow-up, current smoking at baseline was not associated with worse QOL. In 2000 and 2005 follow-up, smoking is significantly associated with worse QOL, OR = 2.11[95%CI: 1.33, 3.36, P<0.01], OR = 2.29[95%CI:1.38, 3.80, P < 0.001], respectively. In 2012 follow-up, smoking is not associated with QOL. Sensitivity analysis didn't change the result significantly. CONCLUSIONS: In this study we found that baseline smoking is associated worse QOL in long-follow-up.

Association between awareness of limiting food intake and all-cause mortality: A cohort study in Japan.

BACKGROUND: Improving diets requires an awareness of the need to limit foods for which excessive consumption is a health problem. Since there are limited reports on the link between this awareness and mortality risk, we examined the association between awareness of limiting food intake (energy, fat, and sweets) and all-cause mortality in a Japanese cohort study. METHODS: Participants comprised 58,772 residents (27,294 men; 31,478 women) aged 35-69 years who completed baseline surveys of the Japan Multi-Institutional Collaborative Cohort Study from 2004 to 2014. Hazard ratios (HRs) for all-cause mortality and 95% confidence intervals (CIs) were estimated by sex using a Cox proportional hazard model, with adjustment for related factors. Mediation analysis with fat intake as a mediator was also conducted. RESULTS: The mean follow-up period was 11 years and 2,516 people died. Estimated energy and fat intakes according to the Food Frequency Questionnaire were lower in those with awareness of limiting food intake than in those without this awareness. Women with awareness of limiting fat intake showed a significant decrease in mortality risk (HR=0.73; 95% CI, 0.55 to 0.94). Mediation analysis revealed that this association was due to the direct effect of the awareness of limiting fat intake and that the total effect was not mediated by actual fat intake. Awareness of limiting energy or sweets intake was not related to mortality risk reduction. CONCLUSION: Awareness of limiting food intake had a limited effect on reducing all-cause mortality risk.

A heterodimeric hyaluronate lyase secreted by the activated sludge bacterium Haliscomenobacter hydrossis.

Haliscomenobacter hydrossis is a filamentous bacterium common in activated sludge. The bacterium was found to utilize hyaluronic acid, and hyaluronate lyase activity was detected in its culture. However, no hyaluronate lyase gene was found in the genome, suggesting the bacterium secretes a novel hyaluronate lyase. The purified enzyme exhibited two bands on SDS-PAGE and a single peak on gel filtration chromatography, suggesting a heterodimeric composition. N-terminal amino acid sequence and mass spectrometric analyses suggested that the subunits are molybdopterin-binding and [2Fe-2S]-binding subunits of a xanthine oxidase family protein. The presence of the cofactors was confirmed using spectrometric analysis. Oxidase activity was not detected, revealing that the enzyme is not an oxidase but a hyaluronate lyase. Nuclear magnetic resonance analysis of the enzymatic digest revealed that the enzyme breaks hyaluronic acid to 3-(4-deoxy-ß-d-gluc-4-enuronosyl)-N-acetyl-d-glucosamine. As hyaluronate lyases (EC 4.2.2.1) are monomeric or trimeric, the enzyme is the first heterodimeric hyaluronate lyase.

Complex Formation of an RNA Aptamer with a Part of HIV-1 Tat through Induction of Base Triples in Living Human Cells Proven by In-Cell NMR.

An RNA aptamer that strongly binds to a target molecule has the potential to be a nucleic acid drug inside living human cells. To investigate and improve this potential, it is critical to elucidate the structure and interaction of RNA aptamers inside living cells. We examined an RNA aptamer for HIV-1 Tat (TA), which had been found to trap Tat and repress its function in living human cells. We first used in vitro NMR to examine the interaction between TA and a part of Tat containing the binding site for trans-activation response element (TAR). It was revealed that two U-A∗U base triples are formed in TA upon binding of Tat. This was assumed to be critical for strong binding. Then, TA in complex with a part of Tat was incorporated into living human cells. The presence of two U-A∗U base triples was also revealed for the complex in living human cells by in-cell NMR. Thus, the activity of TA in living human cells was rationally elucidated by in-cell NMR.

Differential Association of Serum n-3 Polyunsaturated Fatty Acids with Various Cerebrovascular Lesions in Japanese Men.

BACKGROUND: An association between a high intake of marine-derived n-3 polyunsaturated fatty acids (n-3 PUFAs) with a lower risk of coronary heart disease was previously reported. However, the association between n-3 PUFAs and cerebrovascular lesions remains unclear. We evaluated this association in a general-population-based sample of Japanese men. METHODS: Participants were community-dwelling men (40-79 years old) living in Kusatsu City, Shiga, Japan. Serum concentrations of n-3 PUFAs, defined as the sum of eicosapentaenoic and docosahexaenoic acids, were measured via gas-liquid chromatography between 2006 and 2008. Magnetic resonance imaging was used to assess cerebrovascular lesions (including intracerebral large-artery stenosis, lacunar infarction, and microbleeds) and white matter lesions between 2012 and 2015. Logistic regression adjusting for conventional cardiovascular risk factors was used to estimate the odds ratio of prevalent cerebrovascular lesions per 1 standard deviation higher serum concentration of n-3 PUFAs. RESULTS: Of a total of 739 men, the numbers (crude prevalence in %) of prevalent cerebral large-artery stenoses, lacunar infarctions, microbleeds, and white matter lesions were 222 (30.0), 162 (21.9), 103 (13.9), and 164 (22.2), respectively. A 1 standard deviation higher concentration of n-3 PUFAs (30.5 µmol/L) was independently associated with lower odds of cerebral large-artery stenosis (multivariable-adjusted odds ratio, 0.80; 95% confidential interval, 0.67-0.97). There were no significant associations of n-3 PUFAs with the other types of lesions. CONCLUSIONS: n-3 PUFAs may have protective effects against large-artery stenosis, but not small vessel lesions, in the brain.

Premature Atrial Contractions and Their Determinants in a General Population of Japanese Men.

BACKGROUND: Premature atrial contractions (PACs) are predictors of atrial fibrillation, stroke, and cardiovascular mortality. The present study aimed to assess relevant factors for PACs among a general population of Japanese men.Methods and Results: This study conducted a population-based, cross-sectional study among 517 men, aged 40-79 years, with neither apparent myocardial infarction nor atrial fibrillation. 24-h Holter electrocardiography to assess PAC frequency was used. Age, body mass index, height, low-density lipoprotein cholesterol, triglycerides, high-density lipoprotein cholesterol, mean heart rate, diabetes mellitus, hypertension, physical activity, smoking, alcohol consumption, and lipid-lowering therapy were included in multivariable negative binomial regression analyses to assess correlation for the number of PACs per hour. Almost all participants (99%) had at least 1 PAC in 1 h (median number 2.84 PACs per h). In multivariable negative binomial regression after adjusting for all covariates simultaneously, age (relative risk [95% confidence interval], 1.30 [1.08-1.57] per 1-standard deviation [SD] increment), height (1.19 [1.02-1.39] per 1-SD increment), triglycerides (0.79 [0.65-0.97] per 1-SD increment), mean heart rate (0.69 [0.59-0.80] per 1-SD increment), physical activity (0.63 [0.43-0.93]), current smoking (1.69 [1.06-2.69]), current moderate (1.97 [1.23-3.16]) and heavy (1.84 [1.12-3.01]) alcohol consumption were independently associated with PAC frequency. CONCLUSIONS: PAC frequency was independently associated with age, height, smoking, alcohol consumption, heart rate, physical activity, and triglycerides.

Relationship Between Non-fasting Triglycerides and Cardiovascular Disease Mortality in a 20-year Follow-up Study of a Japanese General Population: NIPPON DATA90.

BACKGROUND: Non-fasting triglycerides (TG) are considered a better predictor of cardiovascular disease (CVD) than fasting TG. However, the effect of non-fasting TG on fatal CVD events remains unclear. In the present study, we aimed to explore the relationship between non-fasting TG and CVD mortality in a Japanese general population. METHODS: A total of 6,831 participants without a history of CVD, in which those who had a blood sampling over 8 hours or more after a meal were excluded, were followed for 18.0 years. We divided participants into seven groups according to non-fasting TG levels: ≤59 mg/dL, 60-89 mg/dL, 90-119 mg/dL, 120-149 mg/dL, 150-179 mg/dL, 180-209 mg/dL, and ≥210 mg/dL, and estimated the multivariable-adjusted hazard ratios (HRs) of each TG group for CVD mortality after adjusting for potential confounders, including high density lipoprotein cholesterol. Additionally, we performed analysis stratified by age <65 and ≥65 years. RESULTS: During the follow-up period, 433 deaths due to CVD were detected. Compared with a non-fasting TG of 150-179 mg/dL, non-fasting TG ≥210 mg/dL was significantly associated with increased risk for CVD mortality (HR 1.56: 95% CI, 1.01-2.41). Additionally, lower levels of non-fasting TG were also significantly associated with increased risk for fatal CVD. In participants aged ≥65 years, lower levels of non-fasting TG had a stronger impact on increased risk for CVD mortality, while higher levels of non-fasting TG had a stronger impact in those aged <65 years. CONCLUSION: In a general Japanese population, we observed a U-shaped association between non-fasting TG and fatal CVD events.

Risk Factors That Most Accurately Predict Coronary Artery Disease Based on the Duration of Follow-up　- NIPPON DATA80.

BACKGROUND: This study assessed sex-specific time-associated changes in the impact of risk factors on coronary artery disease (CAD) mortality in a general population over long-term follow-up.Methods and Results:A prospective longitudinal cohort study was conducted on representative Japanese populations followed up for 29 years. Data from 8,396 participants (3,745 men, 4,651 women) were analyzed. The sex-specific multivariable adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of 4 risk factors (smoking, diabetes, serum total cholesterol [TC], and systolic blood pressure [SBP]) for CAD mortality were calculated at baseline and at 10, 15, 20, 25, and 29 years of follow-up. In men, smoking (HR 3.23; 95% CI 1.16-9.02) and a 1-SD increase in TC (HR 1.82; 95% CI 1.29-2.57) were strongly associated with a higher risk of CAD in the first 10 years, but this association decreased over time. Diabetes (HR 2.30; 95% CI 1.37-3.85) and a 1-SD increase in SBP (HR 1.23; 95% CI 1.00-1.50) were strongly correlated with a higher risk of CAD after 29 years). In women, diabetes was correlated with CAD after 20 years (HR 2.53; 95% CI 1.19-5.36) and this correlation persisted until after 29 years (HR 2.47; 95% CI 1.40-4.35). CONCLUSIONS: The duration of follow-up needed for the accurate assessment of risk factors for CAD mortality varies according to risk factor and sex.

Lipoprotein Particle Profiles Compared With Standard Lipids in the Association With Subclinical Aortic Valve Calcification in Apparently Healthy Japanese Men.

BACKGROUND: Risk factors for atherosclerotic disease including dyslipidemia have been shown to be associated with aortic valve calcification (AVC). Nuclear magnetic resonance (NMR)-measured lipoprotein particles, low-density and high-density lipoprotein particles (LDL-p, HDL-p) in particular, have emerged as novel markers of atherosclerotic disease; however, whether NMR-measured particles are associated with AVC remains to be determined. This study aimed to examine the association between NMR-based lipoprotein particle measurements and standard lipids with AVC. The primary variables of interest were LDL-p (nmol/L), HDL-p (µmol/L), LDL-cholesterol, and HDL-cholesterol (both in mg/dL).Methods and Results:A community-based random sample of Japanese men aged 40-79 years examined in 2006-2008, in Shiga, Japan was studied. Presence of AVC was defined as an Agatston score >0. Lipoprotein particles were measured using NMR spectroscopy. In the main analysis, multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for the prevalence of AVC across the higher quartiles of lipids in reference to the lowest ones were obtained. Of 874 participants analyzed, 153 men had AVC. Multivariable-adjusted ORs of prevalent AVC for the highest vs. the lowest quartile were significantly elevated for LDL-p (OR, 2.20; 95% CI: 1.23-3.93) and LDL-cholesterol (OR, 2.16; 95% CI: 1.23-3.78). In contrast, neither HDL-p nor HDL-cholesterol was associated with AVC. CONCLUSIONS: The association of prevalent AVC with NMR-based LDL-p was comparable to that with LDL-cholesterol.

Investigation of the Interaction of Human Origin Recognition Complex Subunit 1 with G-Quadruplex DNAs of Human c-myc Promoter and Telomere Regions.

Origin recognition complex (ORC) binds to replication origins in eukaryotic DNAs and plays an important role in replication. Although yeast ORC is known to sequence-specifically bind to a replication origin, how human ORC recognizes a replication origin remains unknown. Previous genome-wide studies revealed that guanine (G)-rich sequences, potentially forming G-quadruplex (G4) structures, are present in most replication origins in human cells. We previously suggested that the region comprising residues 413-511 of human ORC subunit 1, hORC1413-511, binds preferentially to G-rich DNAs, which form a G4 structure in the absence of hORC1413-511. Here, we investigated the interaction of hORC1413-511 with various G-rich DNAs derived from human c-myc promoter and telomere regions. Fluorescence anisotropy revealed that hORC1413-511 binds preferentially to DNAs that have G4 structures over ones having double-stranded structures. Importantly, circular dichroism (CD) and nuclear magnetic resonance (NMR) showed that those G-rich DNAs retain the G4 structures even after binding with hORC1413-511. NMR chemical shift perturbation analyses revealed that the external G-tetrad planes of the G4 structures are the primary binding sites for hORC1413-511. The present study suggests that human ORC1 may recognize replication origins through the G4 structure.

Relationship Between Step Counts and Cerebral Small Vessel Disease in Japanese Men.

BACKGROUND AND PURPOSE: Cerebral small vessel disease (CSVD) is a common subclinical feature of the aging brain. Steps per day may contribute to its prevention. We herein investigated the association between step counts and CSVD in a healthy Japanese male population. METHODS: We analyzed data from 680 men who were free of stroke and participated in this observational study. Seven-day step counts were assessed at baseline (2006-2008) using a pedometer. CSVD was assessed at follow-ups (2012-2015) based on deep and subcortical white matter hyperintensities (WMHs), periventricular hyperintensities, lacunar infarcts, and cerebral microbleeds on magnetic resonance imaging. Using a logistic regression analysis, we computed the adjusted odds ratios, with 95% CIs, of prevalent CSVD according to quartiles of step counts (reference: Q1). We also investigated the association between step counts and WMH volumes using a quantile regression. RESULTS: Steps per day were significantly associated with lower odds ratios, with the lowest at Q3 (8175-10 614 steps/day), of higher (versus low or no burden) deep and subcortical WMHs (odds ratio, 0.52 [95% CI, 0.30-0.89]), periventricular hyperintensities (0.50 [95% CI, 0.29-0.86]), and lacunar infarcts (0.52 [95% CI, 0.30-0.91]) compared with Q1 (≤6060 steps/day) but not cerebral microbleeds. An inverse linear association was observed between step counts and WMH volumes. These associations were independent of age and smoking and drinking status and remained consistent when adjusted for vascular risk factors. CONCLUSIONS: We found a J-shaped relationship between step counts and prevalent CSVD in healthy Japanese men, with the lowest risk being observed among participants with ≈8000 to 10 000 steps/day. Higher steps were also associated with lower WMH volumes.

Aggregability of ß(1→4)-linked glucosaminoglucan originating from a sulfur-oxidizing bacterium Thiothrix nivea.

ß-1,4-glucosaminoglucan (GG) was prepared from the sheath of a sulfur-oxidizing bacterium Thiothrix nivea. Recently, GG was found to be adsorbed by cellulose (paper) and is therefore potentially applicable as an aminating agent for cellulose. We attempted to increase the yield of GG using a fed-batch cultivation method. Furthermore, the behavior of GG molecules in water was theoretically and experimentally investigated. NMR analysis in combination with molecular dynamics calculation suggested that GG molecules tend to form soluble aggregates in water. It was experimentally revealed that the self-aggregation is enhanced by the addition of NaCl and reduced temperature. Adsorption of GG onto cellulose via hydrogen bonding was confirmed by molecular dynamics simulation. Adsorption was also promoted in the presence of NaCl but was inhibited by a reduction in temperature. Only 11% of the amino groups in the GG-treated paper was reactive, suggesting that GG molecules adsorbed by the paper were forming aggregates.