Responses of the ecological characteristics and antioxidant enzyme activities in Rotaria rotatoria to UV-B radiation

Hydrobiologia - UV-B radiation is an increasing threat to aquatic organisms and also a potential driving force for zooplankton population dynamics. To explore the ecological effects of UVR on...     

Parkin-independent mitophagy via Drp1-mediated outer membrane severing and inner membrane ubiquitination

Here, we report that acute reduction in mitochondrial translation fidelity (MTF) causes ubiquitination of the inner mitochondrial membrane (IMM) proteins, including TRAP1 and CPOX, which occurs selectively in mitochondria with a severed outer mitochondrial membrane (OMM). Ubiquitinated IMM recruits the autophagy machinery. Inhibiting autophagy leads to increased accumulation of mitochondria with severed OMM and ubiquitinated IMM. This process occurs downstream of the accumulation of cytochrome c/CPOX in a subset of mitochondria heterogeneously distributed throughout the cell (“mosaic distribution”). Formation of mosaic mitochondria, OMM severing, and IMM ubiquitination require active mitochondrial translation and mitochondrial fission, but not the proapoptotic proteins Bax and Bak. In contrast, in Parkin-overexpressing cells, MTF reduction does not lead to the severing of the OMM or IMM ubiquitination, but it does induce Drp1-independent ubiquitination of the OMM. Furthermore, high–cytochrome c/CPOX mitochondria are preferentially targeted by Parkin, indicating that in the context of reduced MTF, they are mitophagy intermediates regardless of Parkin expression. In sum, Parkin-deficient cells adapt to mitochondrial proteotoxicity through a Drp1-mediated mechanism that involves the severing of the OMM and autophagy targeting ubiquitinated IMM proteins.     

SHED aggregate exosomes shuttled miR‐26a promote angiogenesis in pulp regeneration via TGF‐β/SMAD2/3 signalling

ObjectivesPulp regeneration brings big challenges for clinicians, and vascularization is considered as its determining factor. We previously accomplished pulp regeneration with autologous stem cells from deciduous teeth (SHED) aggregates implantation in teenager patients, however, the underlying mechanism needs to be clarified for regenerating pulp in adults. Serving as an important effector of mesenchymal stem cells (MSCs), exosomes have been reported to promote angiogenesis and tissue regeneration effectively. Here, we aimed to investigate the role of SHED aggregate‐derived exosomes (SA‐Exo) in the angiogenesis of pulp regeneration.Materials and MethodsWe extracted exosomes from SHED aggregates and utilized them in the pulp regeneration animal model. The pro‐angiogenetic effects of SA‐Exo on SHED and human umbilical vein endothelial cells (HUVECs) were evaluated. The related mechanisms were further investigated.ResultsWe firstly found that SA‐Exo significantly improved pulp tissue regeneration and angiogenesis in vivo. Next, we found that SA‐Exo promoted SHED endothelial differentiation and enhanced the angiogenic ability of HUVECs, as indicated by the in vitro tube formation assay. Mechanistically, miR‐26a, which is enriched in SA‐Exo, improved angiogenesis both in SHED and HUVECs via regulating TGF‐β/SMAD2/3 signalling.ConclusionsIn summary, these data reveal that SA‐Exo shuttled miR‐26a promotes angiogenesis via TGF‐β/SMAD2/3 signalling contributing to SHED aggregate‐based pulp tissue regeneration. These novel insights into SA‐Exo may facilitate the development of new strategies for pulp regeneration.     

3H-31, A Non-structural Protein of Heliothis virescens ascovirus 3h,Inhibits the Host Larval Cathepsin and Chitinase Activities

Virologica Sinica - 3h-31 of Heliothis virescens ascovirus 3h (HvAV-3h) is a highly conserved gene of ascoviruses. As an early gene of HvAV-3h, 3h-31 codes for a non-structural protein (3H-31) of...     

一株产透明质酸酶的菌株鉴定及酶学性质研究

透明质酸酶可用于药物渗透剂、动物皮革松散及低分子量的透明质酸制备.实验室前期筛选了一株具有较高透明质酸降解能力的菌株,本研究对其进行了 16S rRNA基因和生理生化反应鉴定,鉴定为弗氏柠檬酸杆菌,但弗氏柠檬酸杆菌来源的透明质酸酶的功能还未见报道.因而,以透明质酸为底物研究其酶学性质,结果表明:该酶最适pH值为5.5,在pH值4.0～8.0下处理1 h可以保持60％以上酶活力;最适温度为50℃,在50℃和60℃下处理1h后剩余60％以上的酶活力.该酶和人源透明质酸酶最适pH相似,但其耐热性更高.因此,本研究挖掘到了新颖的透明质酸酶的资源,并为其开发利用提供了参考价值.