Tropical cyclones likely enhance chemical weathering but suppress atmospheric CO2 consumption in landslide-dominated catchments

Biogeochemistry - The coupling between chemical weathering (including silicate, carbonate and pyrite weathering) and physical erosion is of high interest in active mountain belts. Participation of...     

水杨酸调控盐胁迫下羽衣甘蓝种子萌发的机理

盐胁迫是植物种子萌发与植株生长的重要限制因子。以羽衣甘蓝(Brassica oleracea var.acephala)名古屋为材料,研究不同盐分对其种子萌发的影响,探索水杨酸(SA)及其合成抑制剂氨基茚磷酸(AIP)处理对羽衣甘蓝种子萌发的调控效应。实验结果表明,150与200 mmol·L^–1 NaCl处理后的羽衣甘蓝种子活力显著降低。盐胁迫显著降低种子的吸水速率、种子活力与幼苗质量,降低苯丙氨酸裂解酶活性与内源SA含量,提高过氧化氢(H2O2)与超氧阴离子(O2^–.)含量。SA可以缓解盐胁迫对羽衣甘蓝种子活力的抑制作用,通过促进内源SA合成,从而提高种子吸水率与种子活力,促进种子对K^+、Mg^2+的吸收,降低Na+含量。此外,外源施加SA能够显著增强超氧化物歧化酶和过氧化物酶活性,降低H2O2与O2^–.的积累。相反,氨基茚磷酸(AIP)处理能够增强盐胁迫对种子萌发的抑制作用,推测这与AIP处理能够显著降低种子内源SA含量密切相关。研究表明外源SA主要通过提高保护酶活性、降低活性氧积累和维持体内离子平衡来增强羽衣甘蓝的耐盐性。     

Modification of donor lymphocyte infusion: how to improve the outcome?

<正>Even after allogeneic hematopoietic stem cell transplantation(HSCT), which has been acknowledged as a curative procedure, relapse of leukemia remains the leading cause of death following transplantation and is a disappointment to transplant physicians. Leukemic relapse occurs due to leukemia cell escape from immune-mediated killing (immune escape) by pre-transplantation conditioning and post-transplantation immune control. Immune exhaustion of donor T     

Survivin withdrawal by nuclear export failure as a physiological switch to commit cells to apoptosis

Apoptosis is a tightly controlled process regulated by many signaling pathways; however, the mechanisms and cellular events that decide whether a cell lives or dies remain poorly understood. Here we showed that when a cell is under apoptotic stress, the prosurvival protein Survivin redistributes from the cytoplasm to the nucleus, thus acting as a physiological switch to commit the cell to apoptosis. The nuclear relocalization of Survivin is a result of inefficient assembly of functional RanGTP–CRM1–Survivin export complex due to apoptotic RanGTP gradient collapse. Subsequently, Survivin undergoes ubiquitination, which not only physically prevents its diffusion back to the cytoplasm but also facilitates its degradation. Together, this spatial and functional regulation of Survivin abolishes its cytoprotective effect toward the apoptotic executors and thus commits a cell to apoptosis. Our data indicate that the withdrawal of Survivin is a novel and active physiological regulatory mechanism that tilts the survival balance and promotes the progression of apoptosis.     

Isoliquiritigenin prevents hyperglycemia-induced renal injuries by inhibiting inflammation and oxidative stress via SIRT1-dependent mechanism

Diabetic nephropathy (DN) as a global health concern is closely related to inflammation and oxidation. Isoliquiritigenin (ISL), a natural flavonoid compound, has been demonstrated to inhibit inflammation in macrophages. Herein, we investigated the effect of ISL in protecting against the injury in STZ-induced type 1 DN and in high glucose-induced NRK-52E cells. In this study, it was revealed that the administration of ISL not only ameliorated renal fibrosis and apoptosis, but also induced the deterioration of renal function in diabetic mice. Mediated by MAPKs and Nrf-2 signaling pathways, respectively, upstream inflammatory response and oxidative stress were neutralized by ISL in vitro and in vivo. Moreover, as further revealed by the results of molecular docking, sirtuin 1 (SIRT1) binds to ISL directly, and the involvement of SIRT1 in ISL-mediated renoprotective effects was confirmed by studies using in vitro models of SIRT1 overexpression and knockdown. In summary, by reducing inflammation and oxidative stress, ISL has a significant pharmacological effect on the deterioration of DN. The benefits of ISL are associated with the direct binding to SIRT1, the inhibition of MAPK activation, and the induction of Nrf-2 signaling, suggesting the potential of ISL for DN treatment.Subject terms: Pharmacology, Molecular biology