Genomic insights into speciation history and local adaptation of an alpine aspen in the Qinghai–Tibet Plateau and adjacent highlands

Natural selection serves as an important agent to drive and maintain interspecific divergence. Populus rotundifolia Griff. is an alpine aspen species that mainly occurs in the Qinghai–Tibet Plateau (QTP) and adjacent highlands, whereas its sister species, P. davidiana Dode, is distributed across southwest and central to northeast China in much lower altitude regions. In this study, we collected genome resequencing data of 53 P. rotundifolia and 42 P. davidiana individuals across their natural distribution regions. Our population genomic data suggest that the two species are well delimitated in the allopatric regions, but with hybrid zones in their adjacent region in the eastern QTP. Coalescent simulations suggest that P. rotundifolia diverged from P. davidiana in the middle Pleistocene with following continuous gene flow since divergence. In addition, we found numerous highly diverged genes with outlier signatures that are likely associated with high-altitude adaptation of these alpine aspens. Our finding indicate that Quaternary climatic changes and natural selection have greatly contributed to the origin and distinction maintenance of P. rotundifolia in the QTP.     

微生境对耐旱石生毛尖紫萼藓水分保持与散失特性的影响

毛尖紫萼藓(Grimmia pilifera)是典型石生耐旱藓类,水分是其生存繁衍的关键影响因素。为探究微生境对毛尖紫萼藓水分生理的影响,在安徽省大龙山国家森林公园低山丘陵区选择3种典型微生境(竹林遮蔽S-1,向阳裸岩E,薜荔灌丛遮蔽S-2),对比研究毛尖紫萼藓个体大小、饱和含水量及脱水过程中的含水量指标在不同微生境间的差异性,综合判断微生境对苔藓水分胁迫耐受性的影响及其权衡特征。结果表明:3种微生境毛尖紫萼藓个体大小及饱和含水量差异显著,其中竹林遮蔽生境毛尖紫萼藓具有较小的个体但拥有较高的内、外含水量。向阳裸岩和薜荔灌丛遮蔽生境植株大小及外吸水量接近,但前者内含水量更高。两荫蔽生境苔藓外吸水量是内吸水量的7倍,显著高于向阳裸岩生境的5.8倍。脱水过程中相同时间点向阳裸岩生境苔藓各含水量指标均高于两遮蔽生境,且达到相同含水量的时间差也随脱水进程持续而逐渐增大,这为向阳裸岩生境苔藓的有效光合作用(即相对含水量不低于35%时)及脱水后期的生理和结构调整赢得更多时间。综合而言,向阳裸岩生境毛尖紫萼藓比荫蔽生境具有更强的脱水耐受性,但后者可以通过增加外部吸水量来弥补失水过快的缺陷,这可能是不同微生境毛尖紫萼藓对水分吸收和保持的权衡策略。     

增温、施肥与种内竞争的交互作用对云杉根系属性的影响

增温、施肥与种内竞争的交互作用对云杉根系属性的影响 物种竞争、气温和土壤养分是青藏高原东部高寒地区影响树木生长的重要因素。虽然已开展了大量关于物种竞争、气温、施肥单因素对树木生长的影响研究,但关于这三者的交互作用对根系生长的影响还知之甚少。因此,本研究拟通过测量根系属性(细根长、根表面积、比根长、比表面积、根尖数、根系分支数等)、根生物量,以及根系养分吸收,研究施肥和增温对物种竞争的影响,并进一步探讨施肥、增温与物种竞争的交互作用对云杉(Picea asperata)生长的影响机制以及所采取的适应策略。研究结果表明,增温、施肥和竞争均提高了细根的氮、钾浓度,但并未影响细根生物量和根长、根表面积、根尖数和根分支数等根系特征。然而,无论是增温、施肥,或是它们的联合作用,与物种竞争进行交互时,均增加了根长、根表面积、根尖数、根系分支数和养分吸收。此外,施肥降低了根比表面积、比根长和单位面积的根尖数和根分支数,增温和竞争的交互作用使根比表面积、比根长下降,其他参数不受温度和竞争的影响。该结果表明,云杉在物种竞争、气候变暖、施肥及其交互作用下保持着保守的营养策略。该研究加强了对树木应对全球变化的生理和生态适应性的理解。     

Evaluation of the efficacy and safety of hydroxychloroquine in comparison with chloroquine in moderate and severe patients with COVID-19

Science China Life Sciences -     

Evaluation of Porcine Intestinal Epitheliocytes as an In vitro Immunoassay System for the Selection of Probiotic Bifidobacteria to Alleviate Inflammatory Bowel Disease

Probiotics and Antimicrobial Proteins - The use of in vitro systems that allow efficient selection of probiotic candidates with immunomodulatory properties could significantly minimize the use of...     

A FOXM1-Targeted Peptide Overcomes 5-Fluorouracil Resistance via Modulating ABC Transporters in Liver Cancer HepG2 Cells

Drug resistance largely limits the efficacy and efficiency of chemotherapeutics, which is a first-line treatment for liver cancer, consequently triggering a complete failure in clinical application. There are numerous attempts in exploring potential strategies for avoiding drug resistance, but none of them has effectively addressed this problem. Therefore, novel molecular targets and agents proposed for addressing drug resistance are needed. This study established 5-fluorouracil (5-Fu)-resistant HepG2 cells (HepG2/R) and showed that a FOXM1-targeted peptide, P201, reactivated 5-Fu to attenuate HepG2/R cell viability, proliferation, migration and promote apoptosis. Moreover, both pharmacological studies and RNA genomic sequencing results uncovered that combination of P201 and 5-Fu notably decreased expressions of FOXM1, MDR1 and ABCG2 compared to 5-Fu alone, indicating P201 overcame 5-Fu resistance mainly through inhibiting FOXM1 and ABC transporters. Therefore, P201 could inhibit ABC transporters by targeting FOXM1 in HepG-2/R cells, overcoming 5-Fu resistance and enhancing anti-cancer drug sensitivity. FOXM1 may be a new target for overcoming 5-Fu resistance in HepG2 cell while the combination treatment of P201 and 5-Fu may serve as a potential strategy for treating liver cancer.