Striatum and globus pallidus structural abnormalities in schizophrenia: A retrospective study of the different stages of the disease.

BACKGROUND: The basal ganglia are important structures for the release of dopamine in the limbic circuits of the midbrain, and the striatum and globus pallidus are the major nuclei of the basal ganglia, and the dysfunction of these regions has been the basis of many models that have attempted to explain the underlying mechanisms of schizophrenia symptoms. The purpose of this study was to investigate the changes in the volume of the striatum subregion and globus pallidus in three different stages of schizophrenia, and to analyze whether these volume changes were related to antipsychotic drugs and schizophrenia symptoms. METHODS: In this study, we investigated the volume of the striatum and globus pallidus in patients with schizophrenia at three different stages. The study included 57 patients with first-episode schizophrenia (FSZ), 51 patients with early-stage schizophrenia (ESZ), 86 patients with chronic schizophrenia (CSZ), and 191 healthy controls (HC), all of whom underwent structured magnetic resonance imaging (MRI) scans. Covariance analysis was performed using SPSS 26.0 was used for covariance analysis to determine whether there were significant differences in striatal subregion and globus pallidus volume between groups, and stratified analysis was used to further eliminate the effect of age on brain volume. Finally, the correlation analysis between the region of interest and the cumulative dose of antipsychotic drugs and psychotic symptoms was performed. RESULTS: The comparison between the different stages of the illness showed significant volume differences in the left caudate nucleus (lCAU) (F = 2.665, adjusted p = 0.048), left putamen (lPUT) (F = 12.749, adjusted p < 0.001), left pallidum (lPAL) (F = 41.111, adjusted p < 0.001), and right pallidum (rPAL) (F = 14.479, adjusted p < 0.001). Post-hoc analysis with corrections showed that the volume differences in the lCAU subregion disappeared. Further stratified analysis controlling for age showed that compared with the HC, the lPAL (t = 4.347, p < 0.001) was initially significantly enlarged in the FSZ group, the lPUT (t = 4.493, p < 0.001), rPUT (t = 2.190, p = 0.031), lPAL (t = 7.894, p < 0.001), and rPAL (t = 4.983, p < 0.001) volumes were all significantly increased in the ESZ group, and the lPUT (t = 3.314, p = 0.002), lPAL (t = 6.334, p < 0.001), and rPAL (t = 3.604, p < 0.001) subregion volumes were also significantly increased in the CSZ group. Correlation analysis showed that lPUT and bilateral globus pallidus were associated with cumulative dose of antipsychotics, but were not associated with clinical symptoms in each subregion. CONCLUSION: The findings suggest that different subregions of the striatum and globus pallidus show significant volume differences at different stages of schizophrenia compared to HC. These volume differences may be strong radiographic evidence for schizophrenia. In addition, the lPAL was the only significantly different brain region observed in the FSZ group, suggesting that it may be a sensitive indicator of early brain structural changes in schizophrenia. Finally, our findings support the hypothesis that antipsychotic drugs have an effect on the volume of brain structures.

New Awareness of the Interplay Between the Gut Microbiota and Circadian Rhythms.

Circadian rhythms influence various aspects of the biology and physiology of the host, such as food intake and sleep/wake cycles. In recent years, an increasing amount of genetic and epidemiological data has shown that the light/dark cycle is the main cue that regulates circadian rhythms. Other factors, including sleep/wake cycles and food intake, have necessary effects on the composition and rhythms of the gut microbiota. Interestingly, the gut microbiota can affect the circadian rhythm of hosts in turn through contact-dependent and contact-independent mechanisms. Furthermore, the gut microbiota has been shown to regulate the sleep/wake cycles through gut-brain-microbiota interaction. In addition to diabetes, the gut microbiota can also intervene in the progression of neuro- degenerative diseases through the gut-brain-microbiota interaction, and also in other diseases such as hypertension and rheumatoid arthritis, where it is thought to have a spare therapeutic potential. Even though fecal microbiota transplantation has good potential for treating many diseases, the risk of spreading intestinal pathogens should not be ignored.

The rate-limiting procedure of 3D DNA walkers and their applications in tandem technology.

DNA walkers, artificial dynamic DNA nanomachines, can mimic actin to move rapidly along a predefined nucleic acid track. They can generally be classified as one- (1D), two- (2D), and three-dimensional (3D) DNA walkers. In particular, 3D DNA walkers demonstrate amazing sustainable walking ability, strong enrichment ability, and fantastic signal amplification ability. In light of these, 3D DNA walkers have been widely used in fields such as biosensors, bioanalysis and cell imaging. Most notably, the strong compatibility of 3D DNA walkers allows their integration with a range of amplification strategies, effectively enhancing signal transduction and amplifying biosensor sensing signals. Herein, we first systematically expound the walking principle of the 3D walkers in this review. Then, by presenting representative examples, the research direction of 3D walkers in recent years is discussed. Furthermore, we also categorize and evaluate diverse tandem signal amplification strategies in 3D walkers. Finally, the challenges and development trends of 3D DNA walkers in the emerging field of analysis are carefully discussed. It is believed that this work can provide new ideas for researchers to quickly understand 3D DNA walkers and their applications in diverse biosensors.

Volumes of hippocampal subfields suggest a continuum between schizophrenia, major depressive disorder and bipolar disorder.

Objective: There is considerable debate as to whether the continuum of major psychiatric disorders exists and to what extent the boundaries extend. Converging evidence suggests that alterations in hippocampal volume are a common sign in psychiatric disorders; however, there is still no consensus on the nature and extent of hippocampal atrophy in schizophrenia (SZ), major depressive disorder (MDD) and bipolar disorder (BD). The aim of this study was to verify the continuum of SZ - BD - MDD at the level of hippocampal subfield volume and to compare the volume differences in hippocampal subfields in the continuum. Methods: A total of 412 participants (204 SZ, 98 MDD, and 110 BD) underwent 3 T MRI scans, structured clinical interviews, and clinical scales. We segmented the hippocampal subfields with FreeSurfer 7.1.1 and compared subfields volumes across the three diagnostic groups by controlling for age, gender, education, and intracranial volumes. Results: The results showed a gradual increase in hippocampal subfield volumes from SZ to MDD to BD. Significant volume differences in the total hippocampus and 13 of 26 hippocampal subfields, including CA1, CA3, CA4, GC-ML-DG, molecular layer and the whole hippocampus, bilaterally, and parasubiculum in the right hemisphere, were observed among diagnostic groups. Medication treatment had the most effect on subfields of MDD compared to SZ and BD. Subfield volumes were negatively correlated with illness duration of MDD. Positive correlations were found between subfield volumes and drug dose in SZ and MDD. There was no significant difference in laterality between diagnostic groups. Conclusion: The pattern of hippocampal volume reduction in SZ, MDD and BD suggests that there may be a continuum of the three disorders at the hippocampal level. The hippocampus represents a phenotype that is distinct from traditional diagnostic strategies. Combined with illness duration and drug intervention, it may better reflect shared pathophysiology and mechanisms across psychiatric disorders.

Machine learning combined with MALDI-TOF MS has the potential ability to identify serotypes of the avian pathogen Riemerella anatipestifer.

AIM: Combining MALDI-TOF MS and machine learning to establish a new rapid method to identify two important serotypes of Rimerella anatipestifer. METHODS AND RESULTS: MALDI-TOF MS was performed on 115 R. anatipestifer strains (serotype 1, serotype 2, and other serotypes) to explore its ability to identify serotypes of R. anatipestifer. Raw spectral data were generated in diagnostic mode; these data were preprocessed, clustered, and analysed using principal component analysis. The results indicated that MALDI-TOF MS completely differentiated serotype 1 from serotype 2 of R. anatipestifer; the potential serotype-associated m/z loci are listed. Furthermore, Random Forest and Support Vector Machine were used for modelling to identify the two important serotypes, and the results of cross-validation indicated that they had ∼80% confidence to make the right classification. CONCLUSION: We proved that MALDI-TOF MS can differentiate serotype 1 from serotype 2 of R. anatipestifer. Additionally, the identification models established in this study have high confidence to screen out these two important serotypes from other serotypes.

Endothelin receptor B enhances liver injury and pro-inflammatory responses by increasing G-protein-coupled receptor kinase-2 expression in primary biliary cholangitis.

Severe diseases like cirrhosis and liver failure can be developed from primary biliary cholangitis (PBC). Endothelin-2 (EDN2) and endothelin receptor B (EDNRB) are related to the pathogenesis of PBC. However, the roles of EDN2 and EDNRB in PBC-related liver injury and inflammation along with molecular mechanisms are poorly defined. In this study, histopathologic alterations of liver tissues were assessed through hematoxylin-eosin staining. Alanine transaminase (ALT), alkaline phosphatase (ALP), aspartate transaminase (AST), and γ-Glutamyltranspetidase (GGT) (4 liver function indexes) serum levels were detected with corresponding activity assay kits. Also, we determined the levels of M2 subtype anti-mitochondrial antibody (AMA-M2), interferon-gamma (IFN-γ), and tumor-necrosis factor alpha (TNFα) in serum with ELISA assay. Later, RT-qPCR assay was used to measure the expression of genes at mRNA levels, while western blotting and immunohistochemical techniques were used to detect protein levels of genes. Our results showed that the liver tissues of PBC patients and mice presented with severe hepatocyte injury and inflammatory cell infiltration as well as destruction of intrahepatic small bile ducts. ALP, AST, ALT, GGT, AMA-M2, IFN-γ, and TNF-α serum levels were higher in PBC patients and mice. Besides, EDN2 and EDNRB were highly expressed in serums and livers of PBC patients and mice. EDNRB potentiated PBC-related liver injury and pro-inflammatory responses, as evidenced by observation of serious liver pathologic injury and increased serum levels of ALP, AST, ALT, AMA-M2, IFN-γ, and TNF-α in PBC mice following EDNRB overexpression. EDNRB overexpression or activation via its agonist IRL-1620 TFA triggered liver injury and pro-inflammatory responses, increased GRK2 expression and induced NF-κB expression and activation in wild-type mice. EDNRB knockdown or inhibition by Bosentan alleviated liver damage and inflammation, reduced GRK2 expression, and inhibited NF-κB in PBC mice. These findings suggested EDNRB loss or inhibition weakened liver injury and pro-inflammatory responses by down-regulating GRK2 and inhibiting the NF-κB pathway in PBC mice.

Electroconvulsive therapy efficacy in adolescents with mental illness: A retrospective comparison.

Background: There is limited evidence on the efficacy of electroconvulsive therapy (ECT) in adolescents with mental illness. The present study reported outcomes of adolescents with mental illness treated with ECT aimed at providing evidence for large-scale feasibility. Objectives: The primary objective of this trial was to examine the differences in demographic and clinical data between responders and non-responders. The secondary objective was to determine whether ECT produced differential readmission rates, the burden of oral medication, and social function in responders and non-responders in the long term. Methods: Patients aged 14-18 years diagnosed with schizophrenia (SCZ), major depressive disorder (MDD), or bipolar disorder (BD) who received ECT between 2015 and 2020 were included in the study. Demographic and clinical data were compared, and both short-term and long-term outcomes were assessed: response on the Clinical Global Impressions-Improvement scale and readmission at follow-up. The independent-sample t-test was used to compare the continuous variables and the X 2 test was used to compare the dichotomous variables with statistical significance at P ≤ 0.05. Results: Four hundred ten adolescents (aged 14-18 years, 53.90% female) received ECT for SCZ, MDD, and BD. The response rate for SCZ, MDD, and BD were 65.61, 78.57, and 69.95%, respectively. Both SCZ (P = 0.008) and BD (P = 0.008) groups had a significant elder age in responders than in non-responders. Besides that MDD responders had a significantly larger number of ECT sessions than non-responders (P = 0.046), the study failed to find a significant difference in other ECT parameters. A significantly higher proportion of readmission was found in BD non-responders than in responders (P = 0.029), there was no difference in the rate of readmission in other diagnostic groups. Conclusions: These data suggested that ECT is an effective treatment for adolescents with severe mental illness, and the rate of readmission was low in the long term. The present study supports that large-scale systematic studies are warranted for further investigation of the response rate of ECT for treating adolescents with mental illness.

Insights into amphicarpy from the compact genome of the legume Amphicarpaea edgeworthii.

Amphicarpy (seed heteromorphy) is a unique and fascinating reproductive strategy wherein a single plant produces both aerial and subterranean fruits. This strategy is believed to be an adaptation to life under stressful or uncertain environments. Here, we sequenced and de novo assembled a chromosome-level genome assembly of the legume Amphicarpaea edgeworthii Benth. The 299-Mb A. edgeworthii genome encodes 27 899 protein-coding genes and is the most compact sequenced legume genome reported until date. Its reduced genome size may be attributed to the reduced long-terminal repeat retrotransposon content, which stems from the unequal homologous recombination. Gene families related to immunity and stress resistance have been contracted in A. edgeworthii, which is consistent with the notion that the amphicarpic reproductive strategy may be a complementary mechanism for its weak environmental-adaptation ability. We demonstrated the 'ABCE' model for the differentiation of chasmogamous and cleistogamous flowers. In addition, the characteristics of aerial and subterranean seeds in hard-seededness were explored. Thus, we suggest that the A. edgeworthii genome, which is the first of an amphicarpic plant, offers significant insights into its unusual reproductive strategy that is a key resource towards comprehending the evolution of angiosperms.

[Characteristics of Nitrogen and Phosphorus Output and Loss Flux in the Shipanqiu Watershed, Three Gorges Reservoir Area].

As the source of non-point pollution in the Three Gorges Reservoir Area, small watershed is a key control object in alleviating deterioration of water quality. In the Three Gorges Reservoir Area, the Shipanqiu small watershed with various land-use types was selected as the research object, and the water quantity and quality of the outlet section of the watershed were continuously monitored. We carried out analysis of the small watershed runoff loss and nitrogen and phosphorus pollutants with concentration, analyzed the morphology change characteristics of runoff erosion, calculated the small watershed of pollutant emission flux, and analyzed the nitrogen and phosphorus nutrient loss and main human and natural factors, especially in the Three Gorges Reservoir Area of agriculture where nonpoint source pollution research has important practical significance. The results showed that the rainfall in the watershed varied significantly with the seasons, and the rainfall was mainly distributed from April to June, which was the main output period of nitrogen and phosphorus loss in the small watershed, accounting for 58.94% and 67.60% of the total nitrogen and phosphorus load, respectively, in the whole year. The total annual runoff in the Shipanqiu small watershed was 8.02×104 m3, and the annual total nitrogen loss flux was 5.04 kg·hm-2, of which nitrate nitrogen (2.54 kg·hm-2) was the main part. The total phosphorus output was 0.534 kg·hm-2, and the soluble total phosphorus (0.422kg·hm-2) accounted for 79.00% of the total phosphorus flux. The loss flux of total nitrogen was 9.51 times that of total phosphorus, and the non-point source pollution risk of nitrogen was much greater than that of phosphorus. Therefore, for the Shipanqiu small watershed, it is especially important to prevent nitrogen loss in paddy fields when fertilization and rainfall coincide.

[Effects of Fertilizer Reduction and Application of Organic Fertilizer on Soil Nitrogen and Phosphorus Nutrients and Crop Yield in a Purple Soil Sloping Field].

The reduction in chemical fertilizers combined with organic fertilizers is a national strategy to achieve environmental friendliness and maintain the quality of cultivated land. It is of great significance for the prevention and control of soil pollution and the sustainable development of agriculture. In this study, purple soil and sloping land in the Three Gorges Reservoir area was studied. The field experiment method was used to study the control, conventional fertilization, optimized fertilization, biochar (fertilizer combined with biochar), and straw under rapeseed/corn rotation mode. The effects of five treatments on soil nitrogen/phosphorus form, crop nitrogen and phosphorus content, fertilizer utilization rate, and crop yield were studied in the field (fertilizer reduction combined with straw returning). The results showed that the soil ammonium nitrogen content was the highest in the rapeseed season, which was 4.51 mg·kg-1. The contents of ammonium nitrogen and alkali nitrogen in the treated corn season were significantly higher than those in the rape season. The reduction in chemical fertilizers can guarantee and increase the total nitrogen content of the soil. Among them, the total nitrogen content in the rapeseed and corn seasons treated with straw was the highest (0.56 g·kg-1 and 0.60 g·kg-1, respectively). The soil treated with straw in the rapeseed season had the highest available phosphorus content (0.76 mg·kg-1). Compared with conventional treatment, the reduction of chemical fertilizers combined with organic fertilizer did not significantly reduce the total phosphorus content of soil. The reduction of fertilization combined with organic fertilizer showed a slight increase in yield but showed the highest yield of rapeseed treated by biochar (2328 kg·hm-2) and the highest yield of conventionally treated maize (5838 kg·hm-2). However, there was no significant difference in each treatment (P>0.05). Regardless of the rapeseed season or the corn season, the reduction of fertilization treatment generally improved the agronomic utilization rate of nitrogen fertilizer and phosphate fertilizer. In the purple soil area, the combination of chemical fertilizer reduction and biochar and straw returning were beneficial to improve soil nutrients, improve fertilizer utilization, and reduce the effects of nitrogen fertilizer and phosphate fertilizer application on crop yield.

[Response of Nitrogen Loss Flux in Purple Soil Sloping Field to Reduced Fertilizer and Combining Straw].

The purple soil sloping field is considered as the main source of sediment and non-point source pollution in the Three Gorges Reservoir area. To prevent and control the non-point source pollution, it is indispensable to explore the characteristics of nitrogen loss in the overland flow and interflow of purple soil sloping field in Three Gorges Reservoir area. The purple soil sloping runoff plots, located in the Shibaozhai Experimental Station of Chengdu Institute of Chinese Academy of Sciences in Zhongxian County, Chongqing, were studied. The experiment included no fertilization treatment (CK), traditional fertilization treatment (T1), amended fertilization treatment (T2), and reduced fertilizer with straw treatment (T3). According to the data of volume of the interflow and runoff and the leach concentration and flux of nitrogen forms under rapeseed-maize rotation system, the response of nitrogen leaching flux to reduce fertilizer with straw application can be definite in purple soil sloping plots. The results show that the ratio of interflow to total runoff is 60.14%-88.56%, and the flux of nitrogen leaching in the interflow accounts for 72.88%-92.35% of total nitrogen loss flux. Ammonium was mainly leached by the overland flow. In addition, nitrate was mainly leached by the interflow and was the main form of nitrogen leaching. The fluxes of ammonium and nitrate under different treatments followed the order T1 > T2 > T3 > CK. The total nitrogen flux of T3 was 20.07 kg·(hm2·a)-1, which was 43.59% and 39.55% lower than that of T1 and T2, respectively. The reduced fertilizer with straw application significantly decreased the leaching flux of ammonium, nitrate, and total nitrogen, and weakened the effect on runoff nitrogen leaching in the purple soil sloping plots.

[Effect of Fertilizer Reduction and Biochar Application on Soil Nitrogen Loss in Purple Upland].

This study seeks to clarify the effect of biochar application on nitrogen loss patterns and flux in purple arid sloping land, so as to provide a scientific basis for improving the quality of farmland and reducing the risk of agricultural non-point source pollution in purple arid sloping land. The effects of four treatments on surface runoff and soil nitrogen loss patterns and fluxes in purple arid sloping land were studied by field experiments, including no fertilization (control), conventional fertilization, optimized fertilization, and biochar (fertilizer reduction and biochar application). The results showed that:① Of the fertilization treatments, the total runoff of conventional treatment was the highest at 16133 L·a-1, and the total runoff of biochar treatment was the lowest at 11893 L·a-1. In each fertilization treatment, soil midstream was the main mode of runoff, accounting for 61.80%-68.60% of the total loss. Compared with the control (no fertilization treatment), the sediment loss in other fertilization treatments was decreased, with conventional treatment showing the most significant effect. ② Ammonium nitrogen is mainly lost by surface runoff, accounting for 86.51%-96.58% of the total loss flux. Biochar treatment had the highest loss flux at 0.69 kg·(hm2·a)-1, and the control treatment had the lowest at 0.17 kg·(hm2·a)-1. ③ The concentration of granular nitrogen in the production flow of each fertilization treatment was higher than that of the control treatment, and the loss flux of granular nitrogen in the conventional fertilization treatment was the highest at 2.87 kg·(hm2·a)-1. ④ There was a significant positive correlation between total nitrogen concentration and nitrate nitrogen concentration in the soil midstream and surface runoff of each fertilization treatment (P<0.01). Nitrate nitrogen is the main form of total nitrogen loss, and both take soil midstream as the main way of loss. The total nitrogen loss through soil flow accounted for 72.86%-89.13%, and that of conventional fertilization was the highest at 35.58 kg·(hm2·a)-1, whereas that of biochar treatment was the lowest at 21.49 kg·(hm2·a)-1. Reducing the amount of fertilizer and applying biochar can significantly reduce the runoff and nitrogen flux, and effectively prevent and control the risk of agricultural non-point source pollution.

Growth hormone receptor promotes breast cancer progression via the BRAF/MEK/ERK signaling pathway.

Growth hormone receptor (GHR), a member of the class I cytokine receptor family, plays key roles in cancer progression. Recently, GHR has been reported to be associated with breast cancer development, but the molecular mechanism of GHR in this malignancy is not fully understood. To investigate this issue, we stably inhibited GHR in breast cancer cell lines, which were observed to reduce cell proliferation, tumor growth and induction of apoptosis, and arrest the cell-cycle arrest at the G1-S phase transition. In addition, GHR silencing suppressed the protein levels of B-Raf proto-oncogene, serine/threonine kinase (BRAF), Mitogen-activated protein kinase kinase (MEK) and Extracellular regulated protein kinases (ERK). These findings suggest that GHR may mediate breast cell progression and apoptosis through control of the cell cycle via the BRAF/MEK/ERK signaling pathway.

A novel cis antisense RNA AsfD promotes Salmonella enterica serovar Typhi motility and biofilm formation.

Bacterial non-coding RNAs (ncRNAs) can participate in multiple biological processes, including motility, biofilm formation, and virulence. Using high-throughput sequencing and transcriptome analysis of Salmonella enterica serovar Typhi (S. Typhi), we identified a novel antisense RNA located at the opposite strand of the flhDC operon. In this study, a northern blot and qRT-PCR were used to confirm the expression of this newfound antisense RNA in S. Typhi. Moreover, 5' RACE and 3' RT-PCR were performed to reveal the molecular characteristics of the antisense RNA, which was 2079 nt - 2179 nt in length, covered the entire flhDC operon sequence, and termed AsfD. The level of AsfD expression was higher during the stationary phase of S. Typhi and activated by the regulators, OmpR and Fis. When AsfD was overexpressed, the level of flagellar gene flhDC transcription increased; moreover, the level of fliA and fljB expression, as well as the motility and biofilm formation of S. Typhi were also enhanced. The results of this study suggest that AsfD is likely to enhance the motility and biofilm formation of S. Typhi by up-regulating flhDC expression.

Aquaporins and their function in root water transport under salt stress conditions in Eutrema salsugineum.

Eutrema salsugineum is considered as extremophile model species. To gain insights into the root hydraulic conductivity and the role played by aquaporins in E. salsugineum, we investigated the aquaporin family profiles, plant water status and root hydraulic conductivity under standard (salt-free) and salt stress conditions. We found that there was no variation in the relative electric conductivity of the leaves when the salt concentration was less than 200 mM NaCl, and the transpiration rate dropped to 60.6% at 100 mM NaCl for 14 days compared to that at standard conditions. The pressure chamber techniques indicated that the root hydraulic conductivity of E. salsugineum was repressed by salt stress. However, propionic acid, usually used as an aquaporin inhibitor, unexpectedly enhanced the root hydraulic conductivity of E. salsugineum. The aquaporin family in E. salsugineum was profiled and the PIP aquaporin expression was investigated at the transcriptional and translational levels. Finally, two EsPIPs were identified to play a role in salt stress. The overall study provides evidence on how halophytes maintain their water status and aquaporin regulation pattern under salt stress conditions.

[Response of the Soil N2O Emission and Ammonia-oxidizing Microorganism Community to the Maize Straw Return with Reducing Fertilizer in Purple Soil].

Crop straw is an important agricultural source, which can replace chemical fertilizers. A field experiment with six different amounts of fertilization combined with maize straw residues was carried out in purple soil, including the control (CK), conventional fertilizing (F), straw return with conventional fertilizing (100FS), straw return with 70% conventional fertilizing (70FS), straw return with 60% conventional fertilizing (60FS), and straw return with 50% regular fertilizing (50FS), to determine the response of the soil N2O emission and ammonia-oxidizing microorganism community distribution to straw return with reducing fertilizer. The dynamic characteristics of the N2O emission in purple soil were observed using an in situ closed chamber and gas chromatography-based system. The ammonia-oxidizing microorganism community distribution was analyzed with multiple molecular techniques (DNA-based clone library and qPCR) linked to physical-chemical soil properties. The results show that the combination of straw with fertilizer increases the N2O emission and cumulative N2O emission. The highest N2O emission[57.59-6238.02 µg·(m2·h)-1]and cumulative N2O emission (60.76 kg·hm-2) were observed for the 100FS treatment. Compared with the F treatment, the soil ammonium nitrogen and nitrate nitrogen contents are reduced and the soil organic matter increases after crop straw return with chemical fertilizer. However, significant changes of the soil total nitrogen and pH were not observed. The bacterial ammonia oxidizer (AOB) amoA gene abundance is higher than that of the archaeal ammonia oxidizer (AOA). The AOA amoA gene abundance during F treatment (50.9×103 copies·g-1) is significantly higher than that of others, while the AOB amoA abundance gene of the F treatment is the lowest (1.36×105 copies·g-1). The 100FS reduces the community diversity and Pielou index of AOA and AOB amoA gene. Their amoA gene abundance significantly declines during 100FS treatment. However, the increment of the AOA and AOB amoA gene diversity and dominant increment of AOB amoA gene abundance are significant when applying straw with reducing fertilizer. The specific AOA indicator OTU1 may be most important with respect to the direct and indirect production of N2O in purple soil. The redundancy analysis (RDA) shows that the community structure of AOA is remarkably relevant to the soil ammonium nitrogen, organic matter, and available phosphorus (P<0.05) and that the community structure of AOB is remarkably relevant to the soil dissolved organic nitrogen, total nitrogen, available potassium, and available phosphorus (P<0.05). The tolerance to different environments and ecological niches of AOB is weaker than that of AOA. Our results illustrate that the maize straw return with 60%-70% regular fertilizing dramatically increases the community diversity and abundance of the AOA and AOB amoA genes and partly mitigates the soil N2O emission without significantly decreasing the vegetable yields.

[Effect of Straw Residues in Combination with Reduced Fertilization Rate on Greenhouse Gas Emissions from a Vegetable Field].

Greenhouse gases mainly come from farmland soils. Re-spreading chaff (straw returning) is an effective ecological management in China. Quantitative analysis of straw residues together with reduced fertilization rates can provide a scientific basis for reducing greenhouse gas emissions. A field experiment with six different fertilizer amounts combined with straw residues was carried out in a vegetable field (lettuce-cabbage-chili rotation), including the control (CK), conventional fertilizing (F), straw returning with 100% conventional fertilizing (100FS), straw returning with 70% conventional fertilizing (70FS), straw returning with 60% conventional fertilizing (60FS),and straw returning with 50% conventional fertilizing (50FS). The dynamic characteristics and emission factors of CO2, CH4 and N2O in the soil were analyzed using an in-situ, closed chamber, gas chromatography-based system, from November 2016 to September 2017. The results showed that the emission of CO2, CH4 and N2O has seasonal variation characteristics. The peak value mainly occurred in April to August, and the gas emission peak would appear after fertilizing and irrigating. Compared with F treatment, straw returning with fertilizing treatments reduced the N2O emission fluxes, cumulative emission and emission factor, especially in the 100FS treatment. The N2O cumulative emission and emission factor was 60.76 kg·hm-2, 0.138 kg·kg-1 (N2O-N/N) respectively in 100FS treatment during planting chili was more than that during planting lettuce and cabbage. Moreover, straw returning with reducing conventional fertilizing could reduce the N2O emission factor compared with 100FS treatment. The CO2 emission fluxes 55.28-1831.62[mg·(m2·h)-1] and cumulative emission (7502.13-25988.55 kg·hm-2) in 70FS treatment were lower than that in CK and F treatments, while other treatments increased the CO2 emission fluxes and cumulative emission, especially in 60FS and 50FS treatments. During planting lettuce and cabbage, the CH4 cumulative emission mainly showed negative values in treatments except for CK, indicating that soil could adsorb CH4. Moreover, straw returning with 30%-50% conventional fertilizing treatment could reduce CH4 emission fluxes and cumulative emission during planting chili, but increased in 100FS. Compared with CK and F treatment, generally, straw retuning with conventional fertilizing could significantly increase the global warming potential (GWP) in the study, except for 70FS treatment. 70FS could reduce the CO2, CH4 emission and the GWP of greenhouse gases, but could not significantly affect N2O emission reduction.

[Effects of Straw and Biochar Addition on Soil Carbon Balance and Ecological Benefits in a Rape-maize Rotation Planting System].

The effects of different straw and biochar applications on the carbon balance of a farmland ecosystem were studied under a rape-maize rotation planting system. The study explored impact of straw and biochar addition on soil carbon sequestration. A field experiment was carried out at the National Monitor Station of Soil Fertility and Fertilizer Efficiency of Purple Soils (Chongqing, China). Five treatments, i.e., control (CK, no organic material), straw only (CS), straw and microorganism (CSD), half straw and half biochar (CSBC), and biochar only (BC), were applied. In-situ cumulative emissions of soil total carbon were subsequently monitored. Based on field experiment and survey data, carbon emissions, carbon sequestration, and and economic and environmental benefits were analyzed for soil respiration, soil carbon pool, crop carbon pool, as well as the cost of agricultural inputs after straw and biochar application. The main results were:①Accumulative emissions of soil carbon during two planting seasons were all higher with treatment than in CK, and the differences between CS, CSD, and CK were significant (P<0.05). ②Compared with CK, both straw and biochar treatments increased crop yield (by 1.49%-3.92%) and crop net primary productivity (NPP) increased by 4.44%-17.90%. Largest yields and NPP during both seasons were achieved with CSD.③Net carbon sequestration was positive during both seasons in all treatments without CK, indicating a carbon sink effect. The highest net carbon sequestration was obtained with CSD (9.05 t·hm-2) and BC (10.75 t·hm-2) treatments. The lowest carbon emissions were obtained with the BC treatment, with emissions 62.69%-81.86% lower than CK. ④The highest production to cost ratio was obtained with CS treatments during the rape planting season. Application of only biochar reduced the production to cost ratio but increased the carbon trading income (466.95-561.22 yuan·hm-2).⑤BC treatment increased carbon productivity (CP) in both seasons, while the economic (CJ) and ecological benefits(CE) of BC treatment were significantly lower than with other treatments. The addition of straw increases economic and ecological benefits; however, addition of biochar reduces such benefits.

[Effects of Straw and Biochar Return in Soil on Soil Aggregate and Carbon Sequestration].

The aim of this work is to understand the effects of straw and biochar return in soil on the content, distribution, stability, and relative contribution rate of organic carbon for soil aggregates, which could be used to better understanding the stability of the soil carbon pool and the protection mechanisms under straw and biochar return. In this study, a field experiment was conducted to study the effects of straw and biochar return on soil aggregates and carbon sequestration characteristics in a rape-maize rotation planting system. Five treatments, including a control (no organic material added, CK), straw (CS), straw and microorganism (CSD), Biochar (BC), half straw and half biochar (CSBC), were used. The results indicated that ① Straw and biochar could improve the content of soil organic carbon, and the BC and CSBC treatments increased it by 16.88-17.37 g·kg-1, values higher than those with the CS and CSD treatments (13.76-14.68 g·kg-1); ② Compared with the CK treatment, CS and CSD treatments could increase the stability of the aggregates through significantly increasing the content of macro-aggregate by 94.00%-117.78% and significantly increasing the mean weight diameter (MWD), geometric mean diameter (GMD), and R0.25 of water stable aggregates, but reducing the D value (P<0.05); and ③ With the increase in aggregate particle size, the content of organic carbon in the aggregates decreased first and then increased. The contribution rate of soil organic carbon in silt and clay was the highest (29.61%-42.18%), and the contribution rate of organic carbon in the macro-aggregate was the lowest (9.19%-17.81%). In addition to the CSD treatment, the CS, BC, and CSBC treatments reduced the contribution of larger aggregates (2-0.25 mm) and micro-aggregates (0.25-0.053 mm). In general, the benefit of straw return was better than that of biochar in promoting soil aggregation. However, the application of biochar was better than straw in improving the aggregates organic carbon content. The newly generated carbon from straw degradation was mainly distributed in large aggregates. Straw with microorganisms could promote the combination of carbon by different components in the larger aggregates. The carbon from biochar and straw with biochar treatments were mainly concentrated in micro-aggregates.