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Aims: Larix kaempferi planting with broad-leaved trees can increase production and alleviate soil degradation; however, the mechanism is unclear, especially on large scales and in different climate regions. This paper attempts to explain the underlying mechanism in a temperate region and northern subtropical alpine region of China. Methods: Litter decomposition rates, nutrient release, enzyme activity and microbial community composition were determined in conifer litter, broad-leaved litter and mixed litter by the litterbag method during about 500 days in the two regions. Results: Decomposition rate was increased by 4.00% in temperate region and 3.38% in the subtropical region after litter mixing and the synergistic effect increased with decomposition progress. However, nutrients release was not always enhanced, and enzyme activities were enhanced at the most of decomposition time and higher in the subtropical region. After litter mixing, a few new dominant taxa emerged, and the microbial gene quantities were increased in the temperate region, but not in the subtropical region. The dominant bacterial taxa were similar, while most of the dominant fungal taxa shifted with decomposition. In addition, the dominant fungi completely differed between the two regions. The environmental variables with greater influence on microbial community were similar in the two regions, including C:N, C:P and pH. Conclusions: After mixing with broad-leaved litter, the decomposition of Larix kaempferi was enhanced by increasing enzyme activities and microbial quantities in the temperate region, but the mechanisms were not clear in the subtropical region. [ABSTRACT FROM AUTHOR]

Background: Deoxyribonuclease 2 (DNase II) plays a key role in clearing cytoplasmic double-stranded DNA (dsDNA). Deficiency of DNase II leads to DNA accumulation in the cytoplasm. Persistent dsDNA in neurons is an early pathological hallmark of senescence and neurodegenerative diseases including Alzheimer's disease (AD). However, it is not clear how DNase II and neuronal cytoplasmic dsDNA influence neuropathogenesis. Tau hyperphosphorylation is a key factor for the pathogenesis of AD. The effect of DNase II and neuronal cytoplasmic dsDNA on neuronal tau hyperphosphorylation remains unclarified. Methods: The levels of neuronal DNase II and dsDNA in WT and Tau-P301S mice of different ages were measured by immunohistochemistry and immunolabeling, and the levels of DNase II in the plasma of AD patients were measured by ELISA. To investigate the impact of DNase II on tauopathy, the levels of phosphorylated tau, phosphokinase, phosphatase, synaptic proteins, gliosis and proinflammatory cytokines in the brains of neuronal DNase II-deficient WT mice, neuronal DNase II-deficient Tau-P301S mice and neuronal DNase II-overexpressing Tau-P301S mice were evaluated by immunolabeling, immunoblotting or ELISA. Cognitive performance was determined using the Morris water maze test, Y-maze test, novel object recognition test and open field test. Results: The levels of DNase II were significantly decreased in the brains and the plasma of AD patients. DNase II also decreased age-dependently in the neurons of WT and Tau-P301S mice, along with increased dsDNA accumulation in the cytoplasm. The DNA accumulation induced by neuronal DNase II deficiency drove tau phosphorylation by upregulating cyclin-dependent-like kinase-5 (CDK5) and calcium/calmodulin activated protein kinase II (CaMKII) and downregulating phosphatase protein phosphatase 2A (PP2A). Moreover, DNase II knockdown induced and significantly exacerbated neuron loss, neuroinflammation and cognitive deficits in WT and Tau-P301S mice, respectively, while overexpression of neuronal DNase II exhibited therapeutic benefits. Conclusions: DNase II deficiency and cytoplasmic dsDNA accumulation can initiate tau phosphorylation, suggesting DNase II as a potential therapeutic target for tau-associated disorders. Scheme depicting the possible mechanism by which DNase II deficiency induces cognitive impairment in mice. DNase II deficiency induces tau phosphorylation by regulating kinases CDK5 and CaMKII as well as phosphatase PP2A through accumulation of undigested damaged DNA in the cytoplasm of neurons. Then phosphorylated tau induces synaptic loss, neuroinflammation, and neuronal apoptosis, eventually rendering cognitive impairment in mice. [ABSTRACT FROM AUTHOR]

The elderly frequently present impaired blood–brain barrier which is closely associated with various neurodegenerative diseases. However, how the albumin, the most abundant protein in the plasma, leaking through the disrupted BBB, contributes to the neuropathology remains poorly understood. We here demonstrated that mouse serum albumin-activated microglia induced astrocytes to A1 phenotype to remarkably increase levels of Elovl1, an astrocytic synthase for very long-chain saturated fatty acids, significantly promoting VLSFAs secretion and causing neuronal lippoapoptosis through endoplasmic reticulum stress response pathway. Moreover, MSA-activated microglia triggered remarkable tau phosphorylation at multiple sites through NLRP3 inflammasome pathway. Intracerebroventricular injection of MSA into the brains of C57BL/6J mice to a similar concentration as in patient brains induced neuronal apoptosis, neuroinflammation, increased tau phosphorylation, and decreased the spatial learning and memory abilities, while Elovl1 knockdown significantly prevented the deleterious effect of MSA. Overall, our study here revealed that MSA induced tau phosphorylation and neuron apoptosis based on MSA-activated microglia and astrocytes, respectively, showing the critical roles of MSA in initiating the occurrence of tauopathies and cognitive decline, and providing potential therapeutic targets for MSA-induced neuropathology in multiple neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

Aims: This study seeks to elucidate the mechanisms by which Bacillus megaterium B6 (strain B6) enhances lead (Pb) transport from roots to branches in Salix integra by approximately one time.Variations in rhizosphere/endosphere microbes, along with changes in metabolites profiles in rhizosphere soil and roots, were assessed using amplicon sequencing and LC–MS, respectively, after inoculation with strain B6 in a controlled pot experiment.Inoculation with strain B6 significantly enhanced species richness and diversities of microbes in both the rhizosphere and endosphere after inoculation with strain B6. The relative abundance of Bacillus, particularly within endosphere microbes, increased markedly. Beneficial microbes, essential for soil remediation, became the dominant species, especially within endosphere communities. Differential metabolites, for example up-regulated amino acids, chelated Pb, reducing its toxicity. These metabolites significantly enriched in "ABC transporters" pathway, promoting Pb transport directly in the root. In the soil, these metabolites either increased Pb bioavailability directly or indirectly by regulating soil properties. Additionally, differential metabolites were significantly correlated with dominant microbes, especially in root, and they played a crucial role in enhancing Pb transport than in Pb bioavailability.After colonization, strain B6 recruited beneficial microbes for soil remediation, altered metabolites expression in plant roots and rhizosphere soil, and consequently enhanced Pb transfer, either directly or indirectly. Furthermore, endosphere microbes played a more significant role in facilitating Pb transport. These findings provide new insights into microbe-assisted phytoremediation in heavy metal-contaminated soil.Methods: This study seeks to elucidate the mechanisms by which Bacillus megaterium B6 (strain B6) enhances lead (Pb) transport from roots to branches in Salix integra by approximately one time.Variations in rhizosphere/endosphere microbes, along with changes in metabolites profiles in rhizosphere soil and roots, were assessed using amplicon sequencing and LC–MS, respectively, after inoculation with strain B6 in a controlled pot experiment.Inoculation with strain B6 significantly enhanced species richness and diversities of microbes in both the rhizosphere and endosphere after inoculation with strain B6. The relative abundance of Bacillus, particularly within endosphere microbes, increased markedly. Beneficial microbes, essential for soil remediation, became the dominant species, especially within endosphere communities. Differential metabolites, for example up-regulated amino acids, chelated Pb, reducing its toxicity. These metabolites significantly enriched in "ABC transporters" pathway, promoting Pb transport directly in the root. In the soil, these metabolites either increased Pb bioavailability directly or indirectly by regulating soil properties. Additionally, differential metabolites were significantly correlated with dominant microbes, especially in root, and they played a crucial role in enhancing Pb transport than in Pb bioavailability.After colonization, strain B6 recruited beneficial microbes for soil remediation, altered metabolites expression in plant roots and rhizosphere soil, and consequently enhanced Pb transfer, either directly or indirectly. Furthermore, endosphere microbes played a more significant role in facilitating Pb transport. These findings provide new insights into microbe-assisted phytoremediation in heavy metal-contaminated soil.Results: This study seeks to elucidate the mechanisms by which Bacillus megaterium B6 (strain B6) enhances lead (Pb) transport from roots to branches in Salix integra by approximately one time.Variations in rhizosphere/endosphere microbes, along with changes in metabolites profiles in rhizosphere soil and roots, were assessed using amplicon sequencing and LC–MS, respectively, after inoculation with strain B6 in a controlled pot experiment.Inoculation with strain B6 significantly enhanced species richness and diversities of microbes in both the rhizosphere and endosphere after inoculation with strain B6. The relative abundance of Bacillus, particularly within endosphere microbes, increased markedly. Beneficial microbes, essential for soil remediation, became the dominant species, especially within endosphere communities. Differential metabolites, for example up-regulated amino acids, chelated Pb, reducing its toxicity. These metabolites significantly enriched in "ABC transporters" pathway, promoting Pb transport directly in the root. In the soil, these metabolites either increased Pb bioavailability directly or indirectly by regulating soil properties. Additionally, differential metabolites were significantly correlated with dominant microbes, especially in root, and they played a crucial role in enhancing Pb transport than in Pb bioavailability.After colonization, strain B6 recruited beneficial microbes for soil remediation, altered metabolites expression in plant roots and rhizosphere soil, and consequently enhanced Pb transfer, either directly or indirectly. Furthermore, endosphere microbes played a more significant role in facilitating Pb transport. These findings provide new insights into microbe-assisted phytoremediation in heavy metal-contaminated soil.Conclusion: This study seeks to elucidate the mechanisms by which Bacillus megaterium B6 (strain B6) enhances lead (Pb) transport from roots to branches in Salix integra by approximately one time.Variations in rhizosphere/endosphere microbes, along with changes in metabolites profiles in rhizosphere soil and roots, were assessed using amplicon sequencing and LC–MS, respectively, after inoculation with strain B6 in a controlled pot experiment.Inoculation with strain B6 significantly enhanced species richness and diversities of microbes in both the rhizosphere and endosphere after inoculation with strain B6. The relative abundance of Bacillus, particularly within endosphere microbes, increased markedly. Beneficial microbes, essential for soil remediation, became the dominant species, especially within endosphere communities. Differential metabolites, for example up-regulated amino acids, chelated Pb, reducing its toxicity. These metabolites significantly enriched in "ABC transporters" pathway, promoting Pb transport directly in the root. In the soil, these metabolites either increased Pb bioavailability directly or indirectly by regulating soil properties. Additionally, differential metabolites were significantly correlated with dominant microbes, especially in root, and they played a crucial role in enhancing Pb transport than in Pb bioavailability.After colonization, strain B6 recruited beneficial microbes for soil remediation, altered metabolites expression in plant roots and rhizosphere soil, and consequently enhanced Pb transfer, either directly or indirectly. Furthermore, endosphere microbes played a more significant role in facilitating Pb transport. These findings provide new insights into microbe-assisted phytoremediation in heavy metal-contaminated soil. [ABSTRACT FROM AUTHOR]