Drought-induced assembly of rhizosphere mycobiomes shows beneficial effects on plant growth.

Beneficial interactions between plants and rhizosphere fungi can enhance plant adaptability during drought stress. However, harnessing these interactions will require an in-depth understanding of the response of fungal community assembly to drought. Herein, by using different varieties of wheat plants, we analyzed the drought-induced changes in fungal community assembly in rhizosphere and bulk soil. We demonstrated that drought significantly altered the fungal communities, with the contribution of species richness to community beta diversity increased in both rhizosphere and bulk soil compartments during drought stress. The stochastic processes dominated fungal community assembly, but the relative importance of deterministic processes, mainly homogeneous selection, increased in the drought-stressed rhizosphere. Drought induced an increase in the relative abundance of generalists in the rhizosphere, as opposed to specialists, and the top 10 abundant taxa that enriched under drought conditions were predominantly generalists. Notably, the most abundant drought-enriched taxon in rhizosphere was a generalist, and the corresponding Chaetomium strain was found capable of improving root length and activating ABA signaling in wheat plants through culture-based experiment. Together, these findings provide evidence that host plants exert a strong influence on rhizospheric fungal community assembly during stress and suggest the fungal communities that have experienced drought have the potential to confer fitness advantages to the host plants. IMPORTANCE: We have presented a framework to integrate the shifts in community assembly processes with plant-soil feedback during drought stress. We found that environmental filtering and host plant selection exert influence on the rhizospheric fungal community assembly, and the re-assembled community has great potential to alleviate plant drought stress. Our study proposes that future research should incorporate ecology with plant, microbiome, and molecular approaches to effectively harness the rhizospheric microbiome for enhancing the resilience of crop production to drought.

The influence of soil acidification on N2O emissions derived from fungal and bacterial denitrification using dual isotopocule mapping and acetylene inhibition.

Denitrification, as both origins and sinks of N2O, occurs extensively, and is of critical importance for regulating N2O emissions in acidified soils. However, whether soil acidification stimulates N2O emissions, and if so for what reason contributes to stimulate the emissions is uncertain and how the N2O fractions from fungal (ffD) and bacterial (fbD) denitrification change with soil pH is unclear. Thus, a pH gradient (6.2, 7.1, 8.7) was set via manipulating cropland soils (initial pH 8.7) in North China to illustrate the effect of soil acidification on fungal and bacterial denitrification after the addition of KNO3 and glucose. For source partitioning, we used and compared SP/δ18O mapping approach (SP/δ18O MAP) and acetylene inhibition technique combined isotope two endmember mixing model (AIT-IEM). The results showed significantly higher N2O emissions in the acidified soils (pH 6.2 and pH 7.1) compared with the initial soil (pH 8.7). The cumulative N2O emissions during the whole incubation period (15 days) ranged from 7.1 mg N kg-1 for pH 8.7-18.9 mg N kg-1 for pH 6.2. With the addition of glucose, relative to treatments without glucose, this emission also increased with the decrement of pH values, and were significantly stimulated. Similarly, the highest N2O emissions and N2O/(N2O + N2) ratios (rN2O) were observed in the pH 6.2 treatment. But the difference was the highest cumulative N2O + N2 emissions, which were recorded in the pH 7.1 treatment based on SP/δ18O MAP. Based on both approaches, ffD values slightly increased with the acidification of soil, and bacterial denitrification was the dominant pathway in all treatments. The SP/δ18O MAP data indicated that both the rN2O and ffD were lower compared to AIT-IEM. It has been known for long that low pH may lead to high rN2O of denitrification and ffD, but our documentation of a pervasive pH-control of rN2O and ffD by utilizing combined SP/δ18O MAP and AIT-IEM is new. The results of the evaluated N2O emissions by acidified soils are finely explained by high rN2O and enhanced ffD. We argue that soil pH management should be high on the agenda for mitigating N2O emissions in the future, particularly for regions where long-term excessive nitrogen fertilizer is likely to acidify the soils.

Global low-carbon energy transition in the post-COVID-19 era.

The COVID-19 pandemic has created significant challenges for energy transition. Concerns about the overwhelming emphasis on economic recovery at the cost of energy transition progress have been raised worldwide. More voices are calling for "green" recovery scheme, which recovers the economy while not compromising on the environment. However, limited academic attention has been paid to comprehensively investigating the implications of COVID-19 for global energy transition. This study thus provides a comprehensive analysis of the dynamics between energy transition and COVID-19 around the world and proposes a low-carbon energy transition roadmap in the post-pandemic era. Using energy data from the International Energy Agency (IEA), we first summarized and reviewed the progress of energy transition prior to COVID-19. Building on prior progress, we identified the challenges for energy transition during the pandemic from the perspectives of government support, fossil fuel divestment, renewable energy production capacity, global supply chain, and energy poverty. However, the pandemic also generates opportunities for global energy transition. We hence also identified potential opportunities for energy transition presented by the pandemic from the perspectives of price competitiveness, policy implementation efficiency, and renewable energy strengths. We further provided an in-depth discussion on the impact of current worldwide economic recovery stimulus on energy transition. Based on the identified challenges and opportunities, we proposed the post-pandemic energy transition roadmap in terms of broadening green financing instruments, strengthening international cooperation, and enhancing green recovery plans. Our study sheds light on a global low-carbon energy transition framework and has practical implications for green recovery schemes in post-pandemic times.

[Identifying the Sources of Groudwater NO3--N in Agricultural Region of Qingdao].

To increase crops yields, applying large amounts of fertilizers has become increasingly common in agricultural regions, resulting in NO3--N groundwater pollution. Agricultural non-point pollution is the main source of groundwater NO3--N pollution. To ensure drinking water safety and quality, it is crucial to clarify the sources of NO3--N pollution in agricultural regions. In this study, 35 sampling sites were randomly selected in the Qingdao agricultural area in 2009 and 2019. The spatial distribution of NO3--N concentration was analyzed by the inverse distance weighting method (IDW). The nitrogen and oxygen isotopes were used as a tool to trace sources of NO3--N and the SIAR model was used to quantify contribution proportion of pollution sources. The results showed that the concentration of NO3--N (average) in groundwater in Qingdao has been reduced from 38.49 mg·L-1 in 2009 to 22.37 mg·L-1 in 2019, but it is still higher than the maximum allowable concentration of NO3--N in drinking water set by the World Health Organization (WHO). The NO3--N concentration gradually increased from south to north both in 2009 and 2019. The cross diagram of δ15N-NO3- and δ18O-NO3- show that the main sources of NO3--N in groundwater in Qingdao are chemical fertilizers, soil nitrogen, and manure and sewage. Water isotopes indicate that precipitation was the main source of groundwater in Qingdao. The SIAR model results indicated that the contribution of each source ranked as follows:manure and sewage (47.42%) > soil nitrogen (27.80%) > chemical fertilizer (14.32%) > atmospheric nitrogen depositions (10.43%). From 2009 to 2019, the quality of groundwater in Qingdao has been improved, but NO3--N pollution still cannot be ignored. According to the results, prevention and control should be made to ensure the safety of drinking water and the sustainable development of agriculture.

Evaluation of N2O sources after fertilizers application in vegetable soil by dual isotopocule plots approach.

Nitrogen (N) fertilizer is the major deriver of nitrous oxide (N2O) emissions in agricultural soil. In the vegetable fields in China both inorganic and organic fertilizers are largely applied as basic sources of nitrogen. Identifying the effects of fertilizer type on soil microbial activities involved in N2O emissions would be of great help for future development of N2O reduction strategies. N2O isotopocule deltas, including δ15Nbulk, δ18O and SP (the 15N site preference in N2O), have been used to analyze microbial pathways of N2O production under different treatments, including bio-organic fertilizer treatment, half bio-organic fertilizer and half urea (mixed fertilizer) treatment, urea treatment and no fertilizer treatment. We measured environmental factors, N2O fluxes and N2O isotopocule deltas to evaluate the dynamics of N2O emissions and constructed the dual isotopocule plots (δ15Nbulk vs. SP and δ18O vs. SP) of the main N2O emission phases to assess contribution of the involved microbial processes (bacterial nitrification, bacterial denitrification, nitrifier denitrification and fungal denitrification). According to the results of the main N2O emission phases, we found that bio-organic fertilizer and mix fertilizer treatments had significantly lower N2O emissions compared to urea treatment, with average N2O fluxes of 1477 ± 204, 1243 ± 187 and 1941 ± 164 µg m-3 h-1, respectively, but there were no significant effects on mineral N and cabbage yield. In addition, the urea treatment and the mixed fertilizer treatment had close and higher nitrogen use efficiency. Furthermore, the δ18O vs. SP plot was useful for providing insight into microbial processes, showing that fungal denitrification/bacterial nitrification was the dominant microbial pathway and bio-organic fertilizer and mix fertilizer treatments had higher denitrification and N2O reduction compared to urea treatment. Those findings demonstrated that the partial replacement of urea with bio-organic fertilizer was a better choice, by means of enhancing denitrification to reduce N2O emissions and also guaranteeing the nitrogen use efficiency and the cabbage yield.

Long noncoding RNA LINC00261 induces chemosensitization to 5-fluorouracil by mediating methylation-dependent repression of DPYD in human esophageal cancer.

Approximately 85% of a single administered dose of 5-fluorouracil (5-FU) will be degraded by dihydropyrimidine dehydrogenase (DYPD). Studies have highlighted a link between the complete or partial loss of DYPD function and clinical responses to 5-FU; however, the underlying molecular basis of DPD deficiency remains poorly understood. Hence, the aim of the present study was to evaluate the prevailing hypothesis which suggests that overexpression of LINC00261 possesses the ability to modulate the methylation-dependent repression of DPYD, ultimately resulting in an elevation of the sensitivity of human esophageal cancer cells to 5-FU. LINC00261 levels were initially quantified, followed by analysis of DYPD methylation within the cancerous tissues collected from 75 patients diagnosed with esophageal cancer undergoing 5-FU-based adjuvant chemotherapy. In an attempt to determine the levels of LINC00261 related to the esophageal cancer cell resistance to 5-FU and to identify the interaction between the levels of LINC00261 and methylation of the DYPD promoter, esophageal cancer cells TE-1 and -5 were prepared, in which LINC00261 and the 5-FU-resistant TE-1 and -5 cells were overexpressed. The levels of LINC00261 were reduced among the cancerous tissues obtained from patients exhibiting resistance to 5-FU. Overexpression of LINC00261 was determined to dramatically inhibit proliferation and resistance to apoptosis among 5-FU-resistant TE-1 and -5 cells, whereas silencing of LINC00261 was determined to enhance proliferation and resistance to apoptosis among the TE-1 and -5 cells. DPYD, a confirmed target of LINC00261, displayed a greater incidence of DNA methylation among patient's sensitive to 5-FU. A key finding revealed that overexpressed LINC00261 could increase the methylation of the DPYD promoter through the recruitment of DNA methyltransferase (DNMT), which, in turn, acts to decrease DPYD activity in 5-FU-resistant TE-1 cells, whereas a reversible change was recorded once the demethylation reagent 5-aza-2'-deoxyctidine was employed to treat the 5-FU-resistant TE-1 cells. Taken together, the results of the study provided evidence emphasizing the distinct antitumor ability of LINC00261 in cases of esophageal cancer, which was manifested by overexpression of LINC00261 detected to increase the sensitivity of human esophageal cancer cells to 5-FU by mediating methylation-dependent repression of DPYD. Our study highlighted the potential of LINC00261 as a novel target capable of improving the chemotherapeutic response and survival of patients with esophageal cancer.-Lin, K., Jiang, H., Zhuang, S.-S., Qin, Y.-S., Qiu, G.-D., She, Y.-Q., Zheng, J.-T., Chen, C., Fang, L., Zhang, S.-Y. Long noncoding RNA LINC00261 induces chemosensitization to 5-fluorouracil by mediating methylation-dependent repression of DPYD in human esophageal cancer.

[Effects of organic and inorganic fertilizers on emission and sources of N2O in vegetable soils.] / æœ‰æœºè‚¥å’Œæ— æœºè‚¥å¯¹èœåœ°åœŸå£¤N2OæŽ’æ”¾åŠå ¶æ¥æºçš„å½±å“.

To clarify the microbial pathway of the N2O production and consumption under different fertilizers and provide theoretical basis for the reduction of N2O emission and rational management of fertilization in vegetable soils, we examined dynamics of N2O flux and isotope signatures under different fertilizer treatments in the vegetable soils of Beijing, by setting up four treatments (organic-acetylene, organic-nonacetylene, inorganic-acetylene, inorganic-nonacetylene) and using the stable isotope technique of natural N2O abundance. The results showed that the cumulative N2O emission from organic-acetylene group, organic-nonacetylene group, inorganic-acetylene group and inorganic-nonacetylene group was (374±37), (283±34), (458±36), (355±41) g·m-2 in cabbage growing season, respectively. N2O fluxes were significantly lower in treatments with organic fertilizer than those with inorganic fertilizer and significantly higher in acetylene group than nonacetylene group. The degree of N2O reduction were similar in both fertilizer treatments, and higher nitrification was found in inorganic fertilizer than organic fertilizer treatments. Acetylene only inhibited partial nitrification and partial N2O reduction at the peak of N2O emission. When the emission was reduced, N2O reduction could be completely suppressed. Therefore, the inorganic fertilizer might trigger nitrification and promote higher N2O emission. The high concentration of N2O could withstand that acetylene to inhibite N2O reduction. Hence, using organic fertilizers instead of some inorganic ones could effectively reduce N2O emission in vegetable soils of Beijing. The N2O concentration threshold should be considered when we identify N2O source by acetylene inhibition method.

Inhibition of N-methyl-N-nitrosourea-induced gastric tumorigenesis by Liuwei Dihuang Pill in db/db mice.

AIM: To investigate the inhibitory effect of Liuwei Dihuang Pill (LDP) on gastric tumorigenesis induced by N-methyl-N-nitrosourea (MNU) in diabetic mice. METHODS: Four-week-old mice were divided into four groups: A, 12 db/m mice treated with MNU and saline, as the non-diabetic control; B, 12 db/db mice treated with MNU and saline, as the diabetic control; C, 12 db/db mice treated with MNU and metformin, as the positive control; and D, 12 db/db mice treated with MNU and LDP. MNU was administrated for 20 wk to induce gastric carcinogenesis. LDP was administrated for 10 wk for improvement of insulin resistance. Body weight and food intake were measured every week. Blood samples were collected for assays of fasting blood glucose, insulin, insulin-like growth factor (IGF)-1, adiponectin and leptin. Stomach tissues were collected for histopathological analysis, immunohistochemical staining of Ki67, quantitative reverse transcription-polymerase chain reaction and western blotting. RESULTS: The incidence of MNU-induced gastric dysplasia was significantly elevated in diabetic (db/db) mice relative to the control (db/m) mice. The incidence of gastric dysplasia was significantly reduced by LDP with suppression of cell proliferation, as demonstrated by a decrease in Ki67 staining. Hyperglycemia, hyperinsulinemia and serum IGF-1 were inhibited by LDP. Expression of IGF-1 and insulin receptor mRNAs was decreased, phosphorylation of IGF-1 receptor and AKT protein was reduced in the stomach tissues by LDP. In addition, adiponectin was increased and leptin was decreased in the serum by LDP. CONCLUSION: LDP decreased risk of gastric dysplasia in type 2 diabetic mice by down-regulation of IGF and insulin activity and correction of adipokines disorders.

Metformin Inhibits N-Methyl-N-Nitrosourea Induced Gastric Tumorigenesis in db/db Mice.

Type 2 diabetes can elevate risk of gastric cancer and metformin, an anti-diabetic agent, has an inhibitory effect against gastric cancer cell in vitro. However, the effect of metformin on type 2 diabetes-related gastric tumorigenesis in vivo is still not clear. In the present study, we aim to detect whether metformin can inhibit increased risk of gastric cancer in diabetic db/db mice and which the potential anti-cancer mechanisms of metformin are. 4-week-old mice were divided into 3 groups (2 db/db mice groups and one wild type mice group). All diabetic and non-diabetic mice were treated with N-Methyl-N-Nitrosourea (MNU) for 20 weeks to induce gastric tumorigenesis. At week 21, one db/db mice group were treated with metformin (5 mg/ml) for 10 weeks and the other 2 groups were treated with saline. Blood samples were collected for testing insulin and insulin-like growth factor (IGF)-1. Stomach tissues were collected for histopathological evaluation and mRNAs analysis. Metformin significantly decreased incidence of MNU-induced gastric dysplasia and cancer in diabetic db/db mice. Furthermore, metformin reduced serum insulin as well as IGF-1, and also suppressed expression of insulin receptor, IGF-1, IGF-1 receptor and several pro-inflammatory cytokines mRNAs in stomach of db/db mice, but did not significantly influence IGF-2 and IGF-2 receptor expressions. The results show that metformin can prevent the risk of gastric cancer in type 2 diabetes and the protective mechanisms may involve in an inhibitory effect of metformin on insulin as well as IGF-1 signals and cancer related pro-inflammatory cytokines.

Angiotensin converting enzyme serum activities: Relationship with Alzheimer's disease.

OBJECTIVE: To determine serum activities of angiotensin-converting enzyme (ACE) as a marker in diagnosis and determine the severity of Alzheimer's disease (AD), METHODS: We measured serum ACE activities in 59 moderate-severe AD, 19 mild AD, 45 amnestic mild cognitive impairment (aMCI) and 39 controls. RESULTS: We found that patients in moderate-severe AD stages showed significantly higher ACE in comparison to aMCI and controls (ANOVA, LSD post hoc test: p: 0.02 and p: 0.01, respectively). Logistic regression analysis showed that if ACE activities added 200 U/L, the superiority of AD risk was 1.18 times higher than before compared with the control group (OR 1.18, 95% CI 1.01-1.74; P=0.49). By means of multivariate linear regression analysis, we found that age (ß coefficient: 7.77; P: 0.01) was significantly associated with ACE activities. However, ACE activities were found to be significantly negatively associated with measures of orientation and immediate recall among the AD patients (r<0, P<0.05), whereas ACE activities were not associated with any MMSE scores among the non-AD groups (P > 0.05).uuuu CONCLUSIONS: ACE serum activity that correlates with age is likely to constitute a potential risk factor for the development of AD. ACE serum activity might be a useful biomarker for disease status with increasingly high ACE from mild stage to moderate-severe stage. Moreover, patients with aMCI could take ACE inhibitor (ACEI) to decrease the incidence of AD, and patients with AD could take ACEI to retard cognitive decline in early AD.

The association of renin-angiotensin system blockade use with the risks of cognitive impairment of aging and Alzheimer's disease: A meta-analysis.

A quantitative meta-analysis was performed to evaluate the association of renin-angiotensin system blockade (RASB) use with the incidence of cognitive impairment of aging and Alzheimer's disease (AD). Pubmed, Embase, and Cochrane Library databases were searched up to October 2015. Ten studies that assessed the relationship between RASB use and the incidence of cognitive impairment of aging or AD were included. When randomized trials and observational studies were combined, the use of RASB was significantly associated with a reduced risk of AD (risk ratio [RR], 0.80; 95% confidence interval [CI] 0.68-0.92) and cognitive impairment of aging (RR, 0.65; 95% CI 0.35-0.94) compared no use of RASB. Meanwhile, in an analysis of subgroups, both subjects with angiotensin converting enzyme inhibitor (ACEI) and angiotensin receptor blocker (ARB) use were lower incidence of AD (RR, 0.87; 95% CI 0.74-1.00; RR, 0.69; 95% CI 0.44-0.93, respectively) than those without, whereas, indirect comparison between ACEI and ARB revealed no significance in the risk of AD (RR, 1.27, 95% CI 0.85-1.89, p=0.245). In an analysis of cognitive impairment of aging, ARB use (RR, 0.40; 95% CI 0.02-0.78), rather than ACEI use (RR, 0.72; 95% CI 0.36-1.09), was shown to decrease the risk of cognitive impairment of aging. In conclusion, RASB treatments, regardless of the drug class, have benefits on prevention of AD, and the effects of ACEI may analogous to ARB. However, the benefit differs according to drug classes for cognitive impairment of aging, with ARB use, rather than ACEI use, being a potential treatment for reducing the incidence of cognitive impairment of aging.

Renin-angiotensin system blockade use and risks of cognitive decline and dementia: A meta-analysis.

OBJECTIVE: To evaluate the effects of renin-angiotensin system blockade (RASB) and its classes on the incidences of cognitive decline and dementia. METHODS: PubMed, the EMBASE database and Cochrane Library were searched through October 2015 for eligible studies. We included ten studies that analyzed the effects of RASB treatment on the incidence of cognitive decline or dementia. RESULTS: We found that the use of RASB was associated with a reduced risk of dementia (RR, 0.84; 95% CI, 0.76-0.92), when randomized trials and observational trials were considered together. Meanwhile, regardless of the drug class, both the angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) were shown to effectively decrease the incidence rate of dementia (RR, 0.89; 95% CI, 0.82-0.96; RR, 0.79; 95% CI, 0.64-0.94, respectively). Furthermore, indirect comparison between ACEIs and ARBs revealed no correlation in incident dementia (RR, 0.89, 95% CI 0.72-1.09, p=0.26). However, centrally acting ACEIs (CACEIs) protected against the occurrence of dementia (RR, 0.94; 95% CI, 0.91-0.97); on the contrary, peripheral ACEIs (PACEIs) increased the risk of dementia (RR, 1.20; 95% CI, 1.00-1.43). In an analysis of cognitive decline, CACEIs use was shown to decrease the risk of cognitive decline (RR, 0.92; 95% CI, 0.83-1.00); however, ARBs use had no significant association with the risk of cognitive decline (RR, 0.98; 95% CI, 0.90-1.05). CONCLUSIONS: RASB antihypertensive drugs may be potential treatments for reducing the incidence of dementia, but ARBs use is likely to be analogous to ACEIs. The association of dementia with CACEIs and PACEIs may be opposite, with CACEIs being effective. Meanwhile, the benefit differing according to drug classes for cognitive decline, CACEIs use, rather than ARBs use, is likely to play protective role in cognitive decline.

Renin-angiotensin system-targeting antihypertensive drugs and risk of vascular cognitive impairment: A meta-analysis.

OBJECTIVES: To evaluate the effects of renin-angiotensin system (RAS)-targeting antihypertensive drugs and its classes on the incidence of vascular cognitive impairment (VCI). METHODS: Pubmed, Embase, and Cochrane Library database of selected articles, and previous systematic reviews through May 2015 were searched. Studies that evaluated the association between use of RAS-targeting drugs and VCI were included. Relative risks (RRs) with 95% confidence intervals (CIs) were pooled using fixed effects models or random effects models. RESULTS: In all studies as a whole, the use of RAS-targeting drugs was significantly associated with a reduced risk of VCI (RR, 0.87; 95% CI, 0.75-0.98) and vascular dementia (VD) (RR, 0.78; 95% CI, 0.64-0.93), compared no use of RAS-targeting drugs. Subgroup analysis showed that subjects with Angiotensin-Converting Enzyme Inhibitors (ACEI) use significantly associated with a reduced incidence of VCI (RR, 0.81; 95% CI 0.70-0.91) and VD (RR, 0.75; 95% CI, 0.57-0.93); however, subjects with Angiotensin Receptor Blockers (ARB) use had not this effect on VCI (RR, 0.94; 95% CI 0.76-1.13) or VD (RR, 0.94; 95% CI, 0.45-1.44). In an analysis of subgroups, case-control studies found that the use of RAS-targeting drugs could effectively decrease the incidence of VCI (RR, 0.77; 95% CI 0.66-0.87) and VD (RR, 0.77; 95% CI, 0.66-0.88); however, the randomized trials alone showed no significant effect on the incidence of VCI (RR, 0.94; 95% CI 0.82-1.07) or VD (RR, 0.94; 95% CI, 0.35-1.53). Meanwhile, in an analysis of cognitive impairment of vascular origin (VaCI), no significant association was found between RAS-targeting drugs, ACEI, or ARB and the incidence of VaCI. CONCLUSION: RAS-targeting drugs treatment may produce remarkable efficacy on reducing the incidence of VCI and VD. Meanwhile, ACEI use, rather than ARB use, significantly protects against VCI and VD incidence. However, among the classes of RAS-targeting drugs, neither ACEI nor ARB plays protective role in VaCI incidence. Further more RCTs are required to reliably establish whether RAS-targeting drugs use decreases the risk of VCI (VD and VaCI).