Characteristics of the microbial communities regulate soil multi-functionality under different cover crop amendments in Ultisol

The use of cover crops is a promising strategy for influencing the soil microbial consortium,which is essential for the delivery of multiple soil functions(i.e.,soil multifunctionality).Nonetheless,relatively little is known about the role of the soil microbial consortium in mediating soil multifunctionality under different cover crop amendments in dryland Ultisols.Here,we assessed the multifunctionality of soils subjected to four cover crop amendments(control,non-amended treatment;RD,radish monoculture;HV,hairy vetch monoculture;and RDHV,radish-hairy vetch mixture),and we investigated the contributions of soil microbial richness,network complexity,and ecological clusters to soil multifunctionality.Our results demonstrated that cover crops whose chemical composition differed from that of the main plant crop promoted higher multifunctionality,and the radish-hairy vetch mixture rendered the highest enhancement.We obtained evidence that changes in soil microbial richness and network complexity triggered by the cover crops were associated with higher soil multifunctionality.Specifically,specialized microbes in a key ecological cluster(ecological cluster 2)of the soil microbial network were particularly important for maintaining soil multifunctionality.Our results highlight the importance of cover crop-induced variations in functionally important taxa for promoting the soil multifunctionality of dryland Ultisols.

二氧化硅基Janus纳米片增韧增强环氧树脂

环氧树脂增韧改性一直伴随其应用发展,纳米粒子增韧环氧树脂具有独特的性能,两侧具有不同组成的Janus纳米片具有更高的比表面积和更加丰富界面行为。文中采用乳液界面溶胶凝胶法制备了各向异性的二氧化硅基Janus纳米片(JNS),并用于增韧环氧树脂(EP)。结果表明,JNS固体颗粒对EP同时具有增韧和增强作用,两侧均能参与环氧树脂交联聚合的JNS2嵌入三维的聚合物骨架网络,双侧的界面作用力大于只有亲水侧的氨基参与环氧树脂交联聚合的JNS1。当JNS2的质量分数为0.5%时,EP/JNS2的冲击强度和断裂伸长率均最大,比纯EP分别提高了57.08%和58.68%。EP/JNS复合材料的刚性和玻璃化转变温度升高,热稳定性有所提高。

E674Q(Shanghai APP mutant),a novel amyloid precursor protein mutation,in familial late-onset Alzheimer's disease

Identified as the pathogenic genes of Alzheimer's disease(AD),APP,PSEN1,and PSEN2 mainly lead to early-onset AD,whose course is more aggressive,and atypical symptoms are more common than sporadic AD.Here,a novel missense mutation,APP E674Q(also named“Shanghai APP”),was detected in a Chinese index patient with typical late-onset AD(LOAD)who developed memory decline in his mid-70s.The results from neuroimaging were consistent with AD,where widespread amyloidβdeposition was demonstrated in 18 F-florbetapir Positron Emission Tomography(PET).APP E674Q is close to theβ-secretase cleavage site and the well-studied Swedish APP mutation(KM670/671NL),which was predicted to be pathogenic in silico.Molecular dynamics simulation indicated that the E674Q mutation resulted in a rearrangement of the interaction mode between APP and BACE1 and that the E674Q mutation was more prone to cleavage by BACE1.The in vitro results suggested that the E674Q mutation was pathogenic by facilitating the BACE1-mediated processing of APP and the production of Aβ.Furthermore,we applied an adeno-associated virus(AAV)-mediated transfer of the human E674Q mutant APP gene to the hippocampi of two-month-old C57Bl/6 J mice.AAV-E674Q-injected mice exhibited impaired learning behavior and increased pathological burden in the brain,implying that the E674Q mutation had a pathogenicity that bore a comparison with the classical Swedish mutation.Collectively,we report a strong amyloidogenic effect of the E674Q substitution in AD.To our knowledge,E674Q is the only pathogenic mutation within the amyloid processing sequence causing LOAD.

Effects of duckweed(Spriodela polyrrhiza)remediation on the composition of dissolved organic matter in effluent of scale pig farms

The swine effluent studied was collected from scale pig farms,located in Yujiang County of Jiangxi Province,China,and duckweed（Spriodela polyrrhiza） was selected to dispose the effluent.The purpose of this study was to elucidate the effects of duckweed growth on the dissolved organic matter composition in swine effluent.Throughout the experiment period,the concentrations of organic matter were determined regularly,and the excitationemission matrix（3DEEM） spectroscopy was used to characterize the fluorescence component.Compared with no-duckweed treatments（controls）,the specific ultra-violet absorbance at 254 nm（SUVA254） was increased by a final average of 34.4%as the phytoremediation using duckweed,and the removal rate of DOC was increased by a final average of 28.0%.In swine effluent,four fluorescence components were identified,including two protein-like（tryptophan,tyrosine） and two humic-like（fulvic acids,humic acids） components.For all treatments,the concentrations of protein-like components decreased by a final average of 69.0%.As the growth of duckweed,the concentrations of humic-like components were increased by a final average of 123.5%than controls.Significant and positive correlations were observed between SUVA254 and humic-like components.Compared with the controls,the humification index（HIX） increased by a final average of 9.0%for duckweed treatments.Meanwhile,the duckweed growth leaded to a lower biological index（BIX） and a higher proportion of microbial-derived fulvic acids than controls.In conclusion,the duckweed remediation not only enhanced the removal rate of organic matter in swine effluent,but also increased the percent of humic substances.