Search

Plant detritus plays a crucial role in regulating belowground biogeochemical processes in forest ecosystems, particularly influencing labile carbon (C) dynamics and overall soil C storage. However, the specific mechanisms by which litter and roots affect soil organic carbon (SOC) and its components in plantations remain insufficiently understood. To investigate this, we conducted a detritus input and removal treatment (DIRT) experiment in a Larix principis-rupprechtii Mayr plantation in the Taiyue Mountains, China, in July 2014. The experiment comprised three treatments: root and litter retention (CK), litter removal (LR), and root and litter removal (RLR). Soil samples were collected from depths of 0–10 cm and 10–20 cm during June, August, and October 2015 to evaluate changes in soil pH, water content (SW), SOC, dissolved organic carbon (DOC), readily oxidizable organic carbon (ROC), and microbial biomass carbon (MBC). The removal of litter and roots significantly increased soil pH (p < 0.05), with pH values being 8.84% and 8.55% higher in the LR and RLR treatments, respectively, compared to CK treatment. SOC levels were significantly reduced by 26.10% and 12.47% in the LR and RLR treatments, respectively (p < 0.05). Similarly, DOC and MBC concentrations decreased following litter and root removal, with DOC content in August being 2.5 times lower than in June. Across all treatments and sampling seasons, SOC content was consistently higher in the 0–10 cm depth, exhibiting increases of 35.15% to 39.44% compared to the 10–20 cm depth (p < 0.001). Significant negative correlations were observed between SOC and the ratios of ROC/SOC, pH, DOC/SOC, and MBC/SOC (R = −0.54 to −0.37; p < 0.05). Path analysis indicated that soil pH had a significant direct negative effect on SOC (p < 0.05), with a standardized path coefficient (β) of −0.36, while ROC had a significant direct positive effect on SOC (β = 0.66, p < 0.05). Additionally, pH indirectly affected SOC by significantly influencing ROC (β = −0.69), thereby impacting SOC indirectly. Random forest analysis also confirmed that the ROC/SOC ratio plays a critical role in SOC regulation. This study reveals the complex interactions between litter and root removal and soil C dynamics in larch plantations, identifying soil pH and ROC as crucial regulator of SOC content. However, the short-term duration and focus on shallow soil depths limit our understanding of long-term impacts and deeper soil C storage. Future research should explore these aspects and consider varying climate conditions to enhance the applicability of our findings. These insights provide a scientific foundation for developing effective forest management strategies and forecasting changes in soil C storage in the context of climate change. [ABSTRACT FROM AUTHOR]

B cell receptor-associated protein 31 (BAP31) is a transmembrane protein that is widely expressed and primarily located in the endoplasmic reticulum (ER). B cells play a crucial role in the immune system, and BAP31 significantly contributes to the functions of various immune cells. However, the specific role of BAP31 in B lymphocytes development remains unknown. In this study, we utilized a mouse model with BAP31 deleted from B cells to investigate its effects. Our findings reveal a block in early B cell development in the bone marrow and a significant decrease in the number of B cells in peripheral lymphoid organs taken from BAP31 B cell conditional knockout (BAP31-BCKO) mice. B cell receptor (BCR) signaling is crucial for the normal development and differentiation of B lymphocytes. BAP31, an endoplasmic reticulum membrane protein, directly regulates the BCR signaling pathway and was shown to be significantly positively correlated with B cell activation and proliferation. These findings establish BAP31 as a crucial regulator of early B cell development. [ABSTRACT FROM AUTHOR]

The differentiation of CD4+T cells is a crucial component of the immune response. The spleen and thymus, as immune organs, are closely associated with the differentiation and development of T cells. Previous studies have suggested that BAP31 may play a role in modulating T cell activation, but the specific impact of BAP31 on T cells through macrophages remains uncertain. In this study, we present evidence that BAP31 macrophage conditional knockout (BAP31-MCKO) mice display an enlarged spleen and thymus, accompanied by activated clustering and disrupted differentiation of CD4+T cells. In vitro co-culture studies were conducted to investigate the impact of BAP31-MCKO on the activation and differentiation of CD4+T cells. The examination of costimulatory molecule expression in BMDMs and RAW 264.7 cells, based on the endoplasmic reticulum function of BAP31, revealed an increase in the expression of antigen presenting molecules, particularly MHC-II molecule, in the absence of BAP31 in BMDMs or RAW264.7 cells. These findings suggest that BAP31 plays a role in the activation and differentiation of CD4+T cells by regulating the MHC class II molecule on macrophages. These results provide further support for the importance of BAP31 in developing interaction between macrophages and CD4+T cells. [ABSTRACT FROM AUTHOR]