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The aberrant changes of fussion/fission-related proteins can trigger mitochondrial dynamics imbalance, which cause mitochondrial dysfunctions and result insulin resistance (IR). However, the relationship between the inner mitochondrial membrane fusion protein optic atrophy 1 (Opa1) and hepatic IR as well as the specific molecular mechanisms of signal transduction has not been fully elucidated. In this study, we explore whether abnormalities in the Opa1 cause hepatic IR and whether berberine (BBR) can prevent hepatic IR through the SIRT1/Opa1 signalling pathway. High-fat diet (HFD)-fed mice and db/db mice are used as animal models to study hepatic IR in vivo. IR, morphological changes, and mitochondrial injury of the liver are examined to explore the effects of BBR. SIRT1/Opa1 protein expression is determined to confirm whether the signalling pathway is damaged in the model animals and is involved in BBR treatment-mediated mitigation of hepatic IR. A palmitate (PA)-induced hepatocyte IR model is established in HepG2 cells in vitro. Opa1 silencing and SIRT1 overexpression are induced to verify whether Opa1 deficiency causes hepatocyte IR and whether SIRT1 improves this dysfunction. BBR treatment and SIRT1 silencing are employed to confirm that BBR can prevent hepatic IR by activating the SIRT1/Opa1 signalling pathway. Western blot analysis and JC-1 fluorescent staining results show that Opa1 deficiency causes an imbalance in mitochondrial fusion/fission and impairs insulin signalling in HepG2 cells. SIRT1 and BBR overexpression ameliorates PA-induced IR, increases Opa1, and improves mitochondrial function. SIRT1 silencing partly reverses the effects of BBR on HepG2 cells. SIRT1 and Opa1 expressions are downregulated in the animal models. BBR attenuates hepatic IR and enhances SIRT1/Opa1 signalling in db/db mice. In summary, Opa1 silencing-mediated mitochondrial fusion/fission imbalance could lead to hepatocyte IR. BBR may improve hepatic IR by regulating the SIRT1/Opa1 signalling pathway, and thus, it may be used to treat type-2 diabetes.

Extensive studies have been performed on the role of 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in metabolic diseases. Our previous study reported glucose could directly regulate hexose-6-phosphate dehydrogenase (H6PDH) and 11β-HSD1. Recently, we further investigated the interplay of H6PDH and 11β-HSD1 and their roles in hepatic gluconeogenesis and insulin resistance to elucidate the importance of H6PDH and 11β-HSD1 in pathogenesis of type 2 diabetes mellitus (T2DM). T2DM rats model and H6PDH or 11β-HSD1 siRNA transfected in CBRH-7919 cells were used to explore the effect of H6PDH and 11β-HSD1 in T2DM. The results showed that the expression and activity of H6PDH and 11β-HSD1 in livers of diabetic rats were increased, with the expressions of PEPCK and G6Pase or liver corticosterone increased apparently. It also showed that H6PDH siRNA and 11β-HSD1 siRNA could inhibit the protein expression and enzyme activity by each other. With H6PDH siRNA, the enhancement of gluconeogenesis was blocked and insulin resistance stimulated by corticosterone was reduced. H6PDH and 11β-HSD1 might be the effective and prospective targets for T2DM and metabolic syndromes, based on the interplay between these two enzymes.

Bamboo and broad-leaved mixed forests have been widely recognized for their advantages in maintaining ecological balance, improving soil fertility, and enhancing biodiversity. To understand the effects of mixed broad-leaved tree species and mixing ratios on soil microbial communities in bamboo and broad-leaved mixed forests, we quantified the structure and diversity responses of soil microbial communities to tree species and mixing ratios using high-throughput sequencing of the 16 S rRNA gene. Three bamboo and broad-leaved tree mixed forests were studied, including bamboo–Castanopsis chinensis Hance mixed forest (CCB), bamboo–Alniphyllum fortune (Hemsl.) Makino mixed forest (AFB), and bamboo–Choerospondias axillaris (Roxb.) B. L. Burtt & A. W. Hill mixed forest (CAB). We assessed the impact of tree species and mixing ratios on soil microbial communities by measuring soil properties and the diversity and composition of soil microbes. The results indicate that soil properties and the diversity and composition of microbial communities are highly dependent on broad-leaved tree species in mixed forests. The mixing ratios had a more pronounced effect on microbial diversity than on richness. In CAB, diversity peaked at mixing ratios of 10%–20% and 20%–40%. The presence of broad-leaved trees significantly altered the relationships among soil bacteria, with CAB showing the highest stability, likely due to the increased diversity and quantity of litter from Choerospondias axillaris. Our results show that the choice of broad-leaved tree species and their mixing ratios significantly influence soil microbial diversity and composition in bamboo–broad-leaf mixed forests. An optimal mixing ratio in CAB can maximize bacterial diversity and stability, providing insights for forest management and promoting ecosystem health and sustainability. [ABSTRACT FROM AUTHOR]

Strip cutting has emerged as a new, efficient, and mechanized bamboo forest management model. To shorten the recovery period in strip cutting management, improve bamboo resource quality, prevent soil degradation, and achieve sustainable management, we selected on-year pure Moso bamboo (Phyllostachys edulis) forests for an 8-meter-wide strip cut. Three fertilization methods were applied in a complete two-factor experiment, including spreading, cave, and bamboo stump fertilization, at three fertilization dosages of 600, 900, and 1200 kg/ha (N:P:K = 3.5:1:2). We investigated the effects of different fertilization treatments on the biomass of new bamboo shoots and soil fertility to provide a reference for identifying the optimal fertilization scheme. The results showed that fertilization treatment increased the individual stand biomass of new Moso bamboo shoots, with a decreasing trend in the proportion of branches and leaves and an increasing proportion of culms in biomass allocation. Fertilization treatment significantly increased the total nitrogen, phosphorus, and potassium and available phosphorus contents in the soil. Overall, fertilization at 900 kg/ha using the spreading method showed the best results in promoting individual plant biomass recovery (5% increase in culm proportion and 4.12 kg increase in biomass per plant) and restoring soil fertility (increase the contents of TN, TP, TK, and AP in the entire soil layer) after strip cutting Moso bamboo forests, which addresses these pertinent issues in the strip cut management model. [ABSTRACT FROM AUTHOR]

Strip clearcutting of Moso bamboo forests in southern China has seen increasing interest as a way of reducing harvesting costs. Previous research has shown that cutting influences the overstory structure and drives changes in the microclimate and soil properties. However, the effects of strip cutting on understory vegetation diversity and composition remain unclear. To better understand the influence of cutting on the understory vegetation, this study compares sites under natural restoration after cut and uncut sites in the Moso bamboo forest. We selected plots that were cut in 2019 (C19) and 2017 (C17), as well as unharvested plots as controls (CK). The results showed that strip clearcutting increased the understory vegetation richness and diversity, and a significant difference (A = 0.23, P = 0.001) existed in the composition of the vegetation between the three treatments. Furthermore, the decrease of soil total phosphorus and total potassium content resulted in the difference in undergrowth vegetation distribution and composition between the uncut plots and the cut plots. Our results suggest that strip clearcutting may not be harmful to biodiversity on a local scale in the Moso bamboo forest. [ABSTRACT FROM AUTHOR]