A potential heavy metals detoxification system in composting: Biotic and abiotic synergy mediated by shell powder.

Regulating heavy metal resistance genes (HMRGs) was an effective method for heavy metal resistant bacteria (HMRB) to cope with heavy metal stress during dairy manure composting. This research aimed to investigate heavy metal detoxification mediated by shell powder (SP) in composting and the response of HMRB and HMRGs to changes in heavy metal bioavailability during composting. Research showed that SP additive reduced the bioavailability of Zu, Cu, and Mn by 10.64%, 13.90% and 14.14%, respectively. SP increased the composition percentage of humic acid (HA) in humus (HS) by 8%. SP enhanced the resistance of Actinobacteria to heavy metals and improved the regulation of HMRGs. Correlation analysis demonstrated that the bioavailability of heavy metals was positively correlated with most HMRGs. HA was significantly negatively correlated with the bioavailability of Zn, Cu and Mn. Therefore, SP additive could be a novel strategy for heavy metals detoxification during composting.

Iron reduction in composting environment synergized with quinone redox cycling drives humification and free radical production from humic substances.

The aim of this paper was to investigate the influence of Fe (III) on humification and free radicals evolution. The experimental data showed that the experimental group (CT) with Fe2(SO4)3 had a better degree of humification than the control group (CK). The humic substances (HS) content was 10% higher in CT (23.94 mg·g-1) than in CK (21.54 mg·g-1) in the final. Fe (III) contributed significantly to the formation of free radicals in HS. The amount of H2O2 in CT increased to 74.8 mmol·kg-1, while CK was only 46.5 mmol·kg-1. The content of semiquinone free radical was 10.32 × 1011 spins/mm3 in CT, 5.11 × 1011 spins/mm3 in CK in the end. Several iron-reducing bacteria were detected in composting, among which Paenibacillus was dominant. The above findings suggested that the application of Fe2(SO4)3 enhanced the iron reduction synergistic quinone redox cycling and promoted the generation of free radicals during the humification of composting.

Mechanism analysis of humification coupling metabolic pathways based on cow dung composting with ionic liquids.

This study focused on how adding ionic liquids (IL) affects composting humification. During the warming and thermophilic phases, addition of IL increased precursors content, and increased the polymerization of humus (HS) at later stages. Furthermore, the final HS and humic acid (HA) content of experimental groups (T) groups 129.79 mg/g and 79.91 mg/g were higher than in control group (CK) 118.57 mg/g and 74.53 mg/g, respectively (p < 0.05). IL up-regulated the gene abundance of metabolism for carbohydrate and amino acid (AA), and promoted the contributions of Actinobacteria and Proteobacteria, which affected humification. The redundancy analysis (RDA) results showed that the citrate-cycle (TCA cycle)(ko0020), pentose phosphate pathway (ko00030), pyruvate metabolism (ko00620), glyoxylate and dicarboxylate metabolism (ko00630), propanoate metabolism (ko00640), butanoate metabolism (ko00650) positively correlated with HA and HI. HA and humification index (HI) positively correlated with AA metabolic pathways, and fulvic acid (FA) was negatively correlated with these pathways. Overall, metabolism for carbohydrate and AA metabolism favored compost humification. ILs improved metabolism for carbohydrate and amino acid metabolism, thus enhancing humification.

Quinone redox cycling drives lignocellulose depolymerization and degradation in composting environments based on metagenomics analysis.

In this study, the effect of Fe3+ on the quinone redox cycling driving lignocellulosic degradation in composting systems was investigated. The results showed that the degradation rates of cellulose, hemicellulose, and lignin were higher in the experimental group (CT) with Fe2(SO4)3 addition than in the blank group (CK) (CT, 52.55 %, 45.14 %, 56.98 %; CK, 49.63 %, 37.34 %, 52.3 %). Changes in the abundance of key enzymes for quinone reduction (AA3_1, AA3_2, AA6) and the structural succession of microbial communities were analyzed by metagenomic analysis. Among them, Fe2(SO4)3 had the most significant effect on AA3_2, with an approximately 8-fold increase in abundance compared to the beginning of composting. The dominant phylum in the composting process was Actinobacteria. In conclusion, the addition of Fe2(SO4)3 contributed to the quinone redox cycling and effectively improved the degradation rate of lignocellulose in composting.

Metagenomics analysis revealed the coupling of lignin degradation with humus formation mediated via shell powder during composting.

This study was the first to explore the effect of shell powder (SP) on lignin degradation and humus (HS) formation during composting. The results showed that the treatment group (T) with SP consumed more polyphenols, reducing sugar and amino acids than the control group (CK), especially the rate of reducing sugar consumption in T (50.61 %) was significantly higher than CK (28.40 %). SP greatly enhanced the efficiency of lignin degradation (T:45.47 %; CK:24.63 %) and HS formation (T:34.93 %; CK:20.16 %). The content of HA in T was 12.94 mg/g while CK was 12.06 mg/g. SP maintained a continuous increase in the relative abundance of AA1, AA3 after cooling phase. Meanwhile, T (48.98 %) significantly increased the abundance of Actinobacteria compared with CK (37.19 %). Actinobacteria, AA1 and AA3 were identified as the main factors promoting lignin degradation and HS formation by correlation analysis. Therefore, adding SP could be a novel strategy to improve compost quality.

Synergistic metabolism of carbon and nitrogen: Cyanate drives nitrogen cycle to conserve nitrogen in composting system.

In this study, HCO3- was used as a co-substrate for cyanate metabolism to investigate its effect on nitrogen cycle in composting. The results showed that the carbamate content in experimental group (T) with HCO3- added was higher than that in control group (CP) during cooling period. Actinobacteria and Proteobacteria were the dominant phyla for cyanate metabolism, and the process was mediated by cyanase gene (cynS). The cynS abundance was 16.6% higher in T than CP. In cooling period, the nitrification gene hao in T was 8.125% higher than CP. Denitrification genes narG, narH, nirK, norB, and nosZ were 25.64%, 35.33%, 45.93%, 36.62%, and 36.12% less than CP, respectively. The nitrogen fixation gene nifH in T was consistently higher than CP in the late composting period. Conclusively, cyanate metabolism drove the nitrogen cycle by promoting nitrification, nitrogen fixation, and inhibiting denitrification, which improved nitrogen retention and compost quality.

Fresh fruit consumption in relation to incident diabetes and diabetic vascular complications: A 7-y prospective study of 0.5 million Chinese adults.

BACKGROUND: Despite the well-recognised health benefits of fresh fruit consumption, substantial uncertainties remain about its potential effects on incident diabetes and, among those with diabetes, on risks of death and major vascular complications. METHODS AND FINDINGS: Between June 2004 and July 2008, the nationwide China Kadoorie Biobank study recruited 0.5 million adults aged 30-79 (mean 51) y from ten diverse localities across China. During ~7 y of follow-up, 9,504 new diabetes cases were recorded among 482,591 participants without prevalent (previously diagnosed or screen-detected) diabetes at baseline, with an overall incidence rate of 2.8 per 1,000 person-years. Among 30,300 (5.9%) participants who had diabetes at baseline, 3,389 deaths occurred (overall mortality rate 16.5 per 1,000), along with 9,746 cases of macrovascular disease and 1,345 cases of microvascular disease. Cox regression yielded adjusted hazard ratios (HRs) associating each disease outcome with self-reported fresh fruit consumption, adjusting for potential confounders such as age, sex, region, socio-economic status, other lifestyle factors, body mass index, and family history of diabetes. Overall, 18.8% of participants reported consuming fresh fruit daily, and 6.4% never/rarely (non-consumers), with the proportion of non-consumers about three times higher in individuals with previously diagnosed diabetes (18.9%) than in those with screen-detected diabetes (6.7%) or no diabetes (6.0%). Among those without diabetes at baseline, higher fruit consumption was associated with significantly lower risk of developing diabetes (adjusted HR = 0.88 [95% CI 0.83-0.93] for daily versus non-consumers, p < 0.001, corresponding to a 0.2% difference in 5-y absolute risk), with a clear dose-response relationship. Among those with baseline diabetes, higher fruit consumption was associated with lower risks of all-cause mortality (adjusted HR = 0.83 [95% CI 0.74-0.93] per 100 g/d) and microvascular (0.72 [0.61-0.87]) and macrovascular (0.87 [0.82-0.93]) complications (p < 0.001), with similar HRs in individuals with previously diagnosed and screen-detected diabetes; estimated differences in 5-y absolute risk between daily and non-consumers were 1.9%, 1.1%, and 5.4%, respectively. The main limitation of this study was that, owing to its observational nature, we could not fully exclude the effects of residual confounding. CONCLUSION: In this large epidemiological study in Chinese adults, higher fresh fruit consumption was associated with significantly lower risk of diabetes and, among diabetic individuals, lower risks of death and development of major vascular complications.

Use of drug treatment for secondary prevention of cardiovascular disease in urban and rural communities of China: China Kadoorie Biobank Study of 0.5 million people.

AIMS: Relatively little is known about the use of medication for the secondary prevention of cardiovascular disease (CVD) events in China, and the relevance to it of socioeconomic, lifestyle and health-related factors. METHODS AND RESULTS: We analysed cross-sectional data from the China Kadoorie Biobank (CKB) of 512,891 adults aged 30-79 years recruited from 1737 rural and urban communities in China. Information about doctor-diagnosed ischaemic heart disease (IHD) and stroke, and the use of medication for the secondary prevention of CVD events, were recorded by interview. Multivariate logistic regression was used to estimate odds ratios (ORs) for use of secondary preventive treatment, adjusting simultaneously for age, sex, area and education. Overall, 23,129 (4.5%) participants reported a history of CVD (3.0% IHD, 1.7% stroke). Among them, 35% reported current use of any of 6 classes of drug (anti-platelet, statins, diuretics, ACE-I, ß-blockers or calcium-channel blockers) for the prevention of CVD events, with the rate of usage greater in those with older age, higher levels of income, education, BMI or blood pressure. The use of these agents was associated positively with history of diagnosed hypertension (OR 7.5; 95% confidence intervals: 7.08-8.06) and diabetes (1.40; 1.28-1.52) and inversely with self-rated health status, but there was no association with years since diagnosis. CONCLUSIONS: Despite recent improvements in hospital care in China, only one in three individuals with prior CVD was routinely treated with any proven secondary preventive drugs. The treatment rates were correlated with the existence of other risk factors, in particular evidence of hypertension.

[Relationship between anthropometric measures and the prevalence of diabetes in adults of Suzhou city, Jiangsu province].

OBJECTIVE: To explore the relationships between anthropometric measures as body mass index (BMI), percentage body fat, waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and the risks of diabetes. METHODS: We analyzed the baseline data of 53 260 participants who were aged 30-79 years and had been enrolled into the China Kadoorie Biobank (CKB) study from Suzhou city,Jiangsu province. Unconditional logistic regression analyses were conducted with adjustment for potential confounders. RESULTS: Overall, 5.3% of the participants had diabetes, with about a half of them being newly detected through on-site screening tests. The prevalence of diabetes increased with age, 61% higher (OR = 1.61, 95% confidence interval: 1.54-1.67) risk of diabetes, with 10 years increase of age. In both genders, all anthropometric measures were positively and significantly associated with diabetes, with the associations of measures in central adiposity stronger than those in general obesity, with WHR as the strongest. Each standard deviation (1- s) with greater WHR (<0.06 in men and 0.07 in women) was associated with 72% (61%-83%) higher risk of diabetes in men and 93% (83%-102%) in women. After adjusting for HC, each WC with 5 cm larger, showing 65% and 57% higher risks in men and women respectively. However, after adjusting for WC, every 5cm greater HC appeared and associated with respective 38% and 34% lower risks. CONCLUSION: Measures on adiposity including BMI, percentage body, WC, WHR and WHtR fat were all positively associated with the prevalence of diabetes. Measures of central obesity, particularly WHR, were more strongly associated with diabetes than measures of general obesity. When WC was under control, HC appeared inversely associated with diabetes.