Advanced glycation end products accelerate ischemia/reperfusion injury through receptor of advanced end product/nitrative thioredoxin inactivation in cardiac microvascular endothelial cells.

The advanced glycation end products (AGEs) are associated with increased cardiac endothelial injury. However, no causative link has been established between increased AGEs and enhanced endothelial injury after ischemia/reperfusion. More importantly, the molecular mechanisms by which AGEs may increase endothelial injury remain unknown. Adult rat cardiac microvascular endothelial cells (CMECs) were isolated and incubated with AGE-modified bovine serum albumin (BSA) or BSA. After AGE-BSA or BSA preculture, CMECs were subjected to simulated ischemia (SI)/reperfusion (R). AGE-BSA increased SI/R injury as evidenced by enhanced lactate dehydrogenase release and caspase-3 activity. Moreover, AGE-BSA significantly increased SI/R-induced oxidative/nitrative stress in CMECs (as measured by increased inducible nitric oxide synthase expression, total nitric oxide production, superoxide generation, and peroxynitrite formation) and increased SI/R-induced nitrative inactivation of thioredoxin-1 (Trx-1), an essential cytoprotective molecule. Supplementation of EUK134 (peroxynitrite decomposition catalyst), human Trx-1, or soluble receptor of advanced end product (sRAGE) (a RAGE decoy) in AGE-BSA precultured cells attenuated SI/R-induced oxidative/nitrative stress, reduced SI/R-induced Trx-1 nitration, preserved Trx-1 activity, and reduced SI/R injury. Our results demonstrated that AGEs may increase SI/R-induced endothelial injury by increasing oxidative/nitrative injury and subsequent nitrative inactivation of Trx-1. Interventions blocking RAGE signaling or restoring Trx activity may be novel therapies to mitigate endothelial ischemia/reperfusion injury in the diabetic population

A single dose of lipopolysaccharide elicits autofluorescence in the mouse brain

One hallmark of aging is autofluorescence (AF) in the brain. However, the underlying mechanism for inducing AF remains unknown. This study aims to determine the cause(s) of this phenomenon. The endogenous expression pattern of AF in mice was examined at differing ages. Intraperitoneal injection of a single dose of lipopolysaccharide (LPS) was performed to induce AF. Copper sulfate was applied to remove AF to allow for further immunofluorescence staining. AF appeared in the mouse brain as early as 3 months of age. In the cortex, AF occurs in the lysosomes of microglia, astrocytes, endothelial cells, and oligodendrocyte lineage cells and its prevalence increases with age. Interestingly, AF never occurs in the pericytes of young or aged brains. LPS administration resulted in a rapid and marked induction of brain AF, similar to the normal aging process. Finally, age-related and induced AF can be eliminated by low concentrations of copper sulfate solution. This pre-treatment is safe for aging and lineage tracing studies. These findings depict that AF in the brain could be associated with the innate immune response against Gram-negative bacteria infection

Dynamic Analysis and Prediction of Food Nitrogen Footprint of Urban and Rural Residents in Shanghai

The food nitrogen (N) footprint reflects the amount of reactive N emission and its impact on the environment as a result of food production and consumption to satisfy the basic food demands of an urban population. The N-Calculator model was used to estimate the food N footprint and its dynamic changes in Shanghai from 2000 to 2017, and the auto regressive integrated moving average (ARIMA) time series model was used to predict the food N footprint in Shanghai from 2018 to 2027. The results show that the food N footprint was higher in urban areas (15.3–18.8 kg N/capita/yr) than rural areas (12.6–17.4 kg N/capita/yr) of Shanghai from 2000 to 2017. The change in the food N footprint was consistent with changes in food consumption in urban and rural areas, and the total food N footprint of urban and rural residents was positively correlated with the per capita disposable income and population whereas it was negatively correlated with the Engel’s Coefficient and price index. It was predicted that the per capita food N footprint will gradually decrease in 2018–2027 in urban areas of Shanghai, but it will generally increase in the rural areas. This study will help to initiate policy interventions for sustainable N management and contribute to the achievement of key sustainable development goals (SDGs)

Grain Yield and Nitrogen Use Efficiency of Late-cropping Rice in Response to Delayed Application of Nitrogen and Altered Plant Spacing in South China

【Objective】In order to further enhance grain yield of rice and nitrogen (N) use efficiency (NUE), N fertilizer was reduced and topdressing was delayed, together with alteration in row and plant spacing and planting density.【Method】In two late seasons, comparison trials were conducted with 8 treatments, including zero applied N (T1), farmers' practice (T2, control), 3 moderately-delayed N topdressing (T3-T5) and 3 highly-delayed N topdressing (T5-T8). T3-T8 also had alteration in N application rate, planting density and row and plant spacing.【Result】In comparison to T2, the average grain yields under T3-T5 were increased by 29.7% and 15.9%, and those of T6-T8 were increased by 26.4% and 18.6% in two late seasons, respectively. In both late seasons, nitrogen uptake and plant growth under T3-T5 and T6-T8 were slower before panicle initiation and they were both increased or accelerated thereafter. Based on average results in two late seasons, leaf area indexes at heading stage were enhanced by 8.5% and 11.8% respectively under T3-T5 and T6-T8 compared with that under T2. Leaf nitrogen contents at heading stage were enhanced by 16.8% and 23.5%, respectively. The numbers of panicles per hectare were increased by 14.5% and 15.2%, panicle size remained unchanged or was increased by 12.5%, sink sizes were increased by 13.6% and 29.3%, seed setting rate was enhanced by 9.0% or remained the same, 1000-grain weight remained identical or was decreased by 9.0%, biomasses were increased by 14.8% and 15.5%, and harvest indexes were increased by 7.2% and 6.4%, respectively. The total amounts of N uptake were increased by 27.6% and 40.7%, N uptake efficiencies were increased by 85.9% and 124.2%, agronomical efficiencies were increased by 99.1% and 102.5%, and partial factor productivity was increased by 32.1% and 36.2%, respectively. Additional N input, dense planting and alteration in row and plant spacing had little effect on yield and NUE. Highly-delayed N topdressing could further expand sink size and improve NUE, but could not enhance grain yield anymore.【Conclusion】With reduced N input, both source and sink of rice were substantially enlarged, and the yield and NUE were dramatically increased under moderately-delayed and highly-delayed N topdressing

The Corrosion Behavior of As-cast Mg–4Al–xEr–0.3Mn Alloys

Magnesium and magnesium alloys are light-weighting candidates as the structure materials. The microstructure and corrosion behavior of Mg–4Al–xEr–0.3Mn (x = 2, 4, 6 all in wt%) alloys were studied. The results showed that the morphology, size and distribution of Mg17Al12 phase were gradually improved with the increasing of Er content, and a large number of Al2Er were observed. The Al2Er inhibited the hydrogen evolution reaction and promoted the growth of passivation film. Er oxides or hydroxides were found on the surface of the passivation film, and the charge transfer resistance of the film was 4447 Ω cm2, while the film resistance was 5852 Ω cm2, which reduced the electron transfer efficiency and improved the density and stability of the passivation film, thus greatly improving the corrosion resistance. As Er content reaches 6 wt%, the corrosion rate decreases by nearly 45 %

Occurrence, Distribution and Risk Assessment of Mercury in Multimedia of Soil-Dust-Plants in Shanghai, China

The urban environment is a complex ecosystem influenced by strong human disturbances in multi-environmental media, so it is necessary to analyze urban environmental pollutants through the comprehensive analysis of different media. Soil, road dust, foliar dust, and camphor leaves from 32 sample sites in Shanghai were collected for the analysis of mercury contamination in soil–road dust–leaves–foliar dust systems. Mercury concentrations in surface soils in Shanghai were the highest, followed by road dust, foliar dust, and leaves, successively. The spatial distribution of mercury in the four environmental media presented different distribution patterns. Except for the significant correlation between mercury concentrations in road dust and mercury concentrations in leaves (r = 0.56, p < 0.001), there was no significant correlation between the other groups in the four media. Besides this, there was no significant correlation between mercury concentrations and land types. The LUR (Land use regression) model was used to assess the impact of urbanization factors on mercury distribution in the environment. The results showed that soil mercury was affected by factories and residential areas. Foliar dust mercury was affected by road density and power plants. Leaf mercury was affected by power plants and road dust mercury was affected by public service areas. The highest average HI (Hazard index) value of mercury in Shanghai was found in road dust, followed by surface soil and foliar dust. The HI values for children were much higher than those for adults. However, the HI values of mercury exposure in all sampling sites were less than one, suggesting a lower health risk level. The microscopic mechanism of mercury in different environmental media was suggested to be studied further in order to learn the quantitative effects of urbanization factors on mercury concentrations

Mapping of QTL for Chlorophyll Content in Rice on High-Density Bin Map

【Objective】The research explored the genetic mechanism for regulating chlorophyll content and its response to nitrogen (N) fertilizer in rice, and provide new molecular marker segments for breeding of high-yield and nitrogen- efficient rice varieties.【Method】The 113 family lines of ZS 97 × MH 63 recombinant inbred lines (RIL, F11) were adopted as tested materials for QTL analysis. Field experiments were performed with split-plot design, N fertilizer rate being the main plots and RIL being subplots. The low N (no N) and normal N (130, 135 N kg/hm2) fertilizer treatments were established in the fields. The chlorophyll meter was used to determine SPAD values of leaves at 30 days after transplanting (30 DAT) and at heading (HD) stage. By using a high-density genetic map containing 1 619 Bin markers, IciMappingv3.4 software and complete interval mapping, QTL for controlling leaf chlorophyll content at two growth stages was mapped.【Result】In two N treatments at two growth stages within two years, a total of 15 QTLs for controlling leaf chlorophyll content were detected and they were located on chromosomes 1, 2, 3, 6, 7, 10 and 11. Each single QTL could explain 1.21%-40.74% of genetic contributions to traits. Through comparison of their physical loci, 6 QTLs were found to have been cloned or have the same loci being known previously for chlorophyll content. Among them, a locus, named qHDCHL6-1, regulating the chlorophyll content of flag leaf at heading stage was detected at 8.45-9.12Mb of chromosome 6. It was stably detected under two N treatments in two years, which explained 1.55%-28.01% of contributions to traits. Through functional annotation, 4 candidate genes related to chlorophyll content of flag leaf were found in the qHDCHL6-1 chromosome interval. These genes were LOC_Os06g15370 (OsNPF3.1), LOC_Os06g15420 (OsAS2), LOC_Os06g15620 (GAS) and LOC_Os06g15590, and the first three of these genes have been cloned【Conclusion】15 QTLs controlling leaf chlorophyll content of rice at 30 DAT and HD stage are detected, and a QTL locus qHDCHL6-1 with stable expression was identified, which contains 4 candidate genes