Phosphatidic acid phosphatase 1 impairs SARS-CoV-2 replication by affecting the glycerophospholipid metabolism pathway

Viruses exploit the host lipid metabolism machinery to achieve efficient replication. We herein characterize the lipids profile reprogramming in vitro and in vivo using liquid chromatography-mass spectrometry-based untargeted lipidomics. The lipidome of SARS-CoV-2-infected Caco-2 cells was markedly different from that of mock-infected samples, with most of the changes involving downregulation of ceramides. In COVID-19 patients'' plasma samples, a total of 54 lipids belonging to 12 lipid classes that were significantly perturbed compared to non-infected control subjects'' plasma samples were identified. Among these 12 lipid classes, ether-linked phosphatidylcholines, ether-linked phosphatidylethanolamines, phosphatidylcholines, and ceramides were the four most perturbed. Pathway analysis revealed that the glycerophospholipid, sphingolipid, and ether lipid metabolisms pathway were the most significantly perturbed host pathways. Phosphatidic acid phosphatases (PAP) were involved in all three pathways and PAP-1 deficiency significantly suppressed SARS-CoV-2 replication. siRNA knockdown of LPIN2 and LPIN3 resulted in significant reduction of SARS-CoV-2 load. In summary, these findings characterized the host lipidomic changes upon SARS-CoV-2 infection and identified PAP-1 as a potential target for intervention for COVID-19.     

中国20座旅游城市人体舒适度指数分析

基于中国20座主要旅游城市1951—2007年的日平均气温和相对湿度资料,分别计算得到其57年的逐日人体舒适度指数,进行了等级划分,界定了舒适月份。结果表明：1)由北向南,中国主要旅游城市舒适月份分布由5—9月逐渐过渡到5月以前、8月或9月以后;舒适天数呈增加趋势。2）沿长江一线,各主要旅游城市舒适月份多分布在4月、5月、10月;长江上游旅游城市舒适天数最多、下游次之、中游最少。3）海拔高度由低到高,主要旅游城市舒适月份分布渐趋于6月和7月,舒适天数趋于减少。4）纬度相近情况下,沿海旅游城市舒适月份和天数多于内陆旅游城市。研究结果可为全国旅游气候资源优势的综合开发、旅行社和游客合理安排旅游度假时间和地点,以及气象部门开展旅游气象服务提供科学依据。     

Arbuscular mycorrhizal fungi affect plant community structure under various nutrient conditions and stabilize the community productivity

Soil biota could have a significant impact on plant productivity and diversity through benefiting plants and mediating plant–plant interaction. However, it is poorly understood how soil biotic factors interaction with abiotic environments affect plant community diversity and composition. Here, we investigate the community‐level consequences of arbuscular mycorrhizal fungi (AMF) interactions with multiple nutrients and their ecological stoichiometry. We conducted a greenhouse experiment manipulating nitrogen (N) and phosphorus (P) to create soil nutrient availability and N:P gradients for microcosm communities with and without AMF. We found that AMF suppressed plant diversity at low P levels, whereas it did not alter the diversity at high P levels because of trade‐offs in the abundance of the dominant and subordinate species. AMF reduced plant diversity at the intermediate N:P ratios, while AMF did not affect the diversity at low and high N:P ratios. P addition decreased the mycorrhizal contribution to community productivity, whereas N addition reduced the negative effects of AMF on productivity at high P levels. AMF decreased community productivity at low N:P ratios but increased it at high N:P ratios. AMF increased the stoichiometric homoeostasis of plant communities, which was positively correlated with the stability of productivity under variations in soil N:P ratios. Our study demonstrates that both resource availability and stoichiometry influence the effect of AMF on plant community productivity and diversity and suggests that AMF may increase the stability of plant communities under variations in the soil nutrients by increasing the stoichiometric homoeostasis of the plant community.     

Defects in cytoskeletal microtubule deployment of microsporocytes contribute to fertility loss in genic male-sterile Chinese cabbage

The microtubular cytoskeleton of male-sterile Chinese cabbage was examined to characterize cytoplasmically based defects during microsporogenesis of fertile and sterile microsporocytes. At the onset of meiosis, microtubules (MTs) in fertile microsporocytes were short and anisotropically oriented in the microsporocyte cytoplasm. As the microsporocytes entered metaphase I, the MTs constructed a bisymmetrical spindle characterized by conspicuous kinetochore fibers closely associated with chromosomes in the medial plane. During anaphase I, interzonal MTs become conspicuous between the two sets of chromosomes and the polar regions become more distant as spindle MTs are depleted, essentially disappearing at telophase I. Radially distributed MTs increased and the microsporocyte entered meiosis II, producing two spindles at angles to one another within the wall of the microsporocyte. Indicative of the completion of anaphase II is the formation of a field of aligned MTs between two non-sister nuclei, after which the cytoplasm produced centripetal furrows, meeting in the center of the cell and dividing it into four microspores at the completion of cytokinesis. In sterile microsporocytes, however, an abnormal arrangement of MTs occurred at the conclusion of anaphase II. Although two spindles formed, the angle and the boundary between the spindles were not maintained. At the onset of telophase II, the two spindles migrated to a central region and laterally fused in irregular orientations in which the decondensing chromatin of the non-sister nuclei may form separate or merged nuclei, followed by irregular cytokinesis. The result of meiosis was 41.8 % two binuclear products, and 58.2 % one diploid and one binuclear sterile products.     

The Strategies for Treating “Alzheimer’s Disease”: Insulin Signaling May Be a Feasible Target

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by senile plaques formed by amyloid-beta (Aβ) extracellularly and neurofibrillary tangles (NFTs) formed by hyperphosphorylated tau protein intracellularly. Apart from these two features, insulin deficiency and insulin resistance have also been observed in AD brains. Thus, AD has also been referred to as type 3 diabetes by some of the scientists in this field. Insulin plays a pivotal role in learning and memory and is involved in regulating tau phosphorylation though the PI3KAkt-GSK3b signaling pathway. Interestingly, recent studies revealed that in AD brains the microglia transformed into a disease-associated microglia (DAM) status in a TREM2-dependent manner to restrain the toxicity of Aβ and propagation of tau. This also correlated with PI3K-Akt signaling through the adaptor of TREM2. Whether insulin has any effect on microglia activation in AD pathology is unclear so far. However, many studies demonstrated that diabetes increased the risk of AD. In this review, we summarize the main strategies for curing AD, including lowering the level of Aβ, suppressing the phosphorylation of tau, the ablation and/or repopulation of microglia, and especially the supply of insulin. We also propose that attention should be given to the influences of insulin on microglia in AD.     

精氨酸激酶基因研究进展

磷酸原激酶(PKs)在细胞能量代谢过程中起着关键作用,其中在无脊椎动物、原生动物和细菌中普遍存在的精氨酸激酶(AKs)已成为开发新型高选择性杀虫剂的潜在靶标。本文从精氨酸激酶基因的表达及其调控、分子进化与功能以及精氨酸激酶基因在害虫防治中的应用等几个方面介绍了国内外有关精氨酸激酶基因的研究进展。     

Amending biochar affected enzyme activities and nitrogen turnover in Phaeozem and Luvisol

Soil nitrogen (N) is a vital source of nutrients for maintaining soil fertility and crop production. However, the effect of biochar application rate on the mechanism of organic N transformation and the contribution of enzyme mineralization is still unclear. Therefore, we conducted two 5-year field experiments in contrasting soils (Phaeozem and Luvisol) with biochar application rate at 0 t hm⁻² (CK, 0), 22.5 t hm⁻² (D₁, 1%), 67.5 t hm⁻² (D₂, 3%), and 112.5 t hm⁻² (D₃, 5%) to investigate the potential effects of biochar application rate on soil organic nitrogen (N) turnover and its linkage to enzymatic mineralization in contrasting soil. The results showed that soil organic carbon (SOC) and microbial biomass nitrogen (MBN) contents, microbial biomass carbon to nitrogen ratio (MBC:MBN) and protease activity are significantly influenced by biochar application rate whereas not by soil type. Ammonium nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃⁻-N) contents, and dehydrogenase activity are significantly changed by soil type whereas not by biochar application rate. Based on the redundancy analysis, we found that organic N fractions are associated with MBN, SOC, and protease in Phaeozem, but related to protease activity in Luvisol. Our findings indicate that organic N turnover is not only related to the bioavailability of N but also requires carbon substrates in Phaeozem, whereas the transformation of organic N in Luvisol is dominated by enzymatic mineralization as the relatively low level of bioavailable N.     

E-learning助推临床微生物教学数字化转型

由于医学知识的快速增加、新病原体的出现、新传染病的产生和新耐药机制的形成,在临床微生物学领域具有学习和应用能力并不断提升是一项不容忽视的挑战。E-learning是一种教学方法,它基于使用电子媒体和设备作为工具,以改善获得培训、交流和互动的机会,并促进学生适应新的知识和技能。在临床微生物学教学和培训中E-learning可以提供更高效灵活的模式来满足教育需求。E-learning为教育工作者提供了新的角色,在数字技术的帮助下设计和促进更好的学习体验,引导学生正确掌握临床微生物学的电子资源,促进了理论和实践差距的缩小。作为一种E-learning的新方法,虚拟实验室通过重新激活和场景模拟提供了更广泛有效的学习平台。多平台整合教育资源,让学生更容易理解和掌握日新月异的医学知识,促进临床微生物教学观念转换、数字化转型和教学模式改革。

     

北京市白河和潮河流域生态健康评价

选取北京市重要的饮用水源密云水库上游白河和潮河流域,结合北京山区流域生态现状,构建了涵盖水域生境结构、水生生物、生态压力和陆域生态格局与功能、生态压力5大类13项指标的评价指标体系,开展了流域生态健康评价。结果表明白河和潮河流域的健康状态整体处于良好等级,但水生生物和陆域生态格局状况相对较差。14个子流域的健康状况差异并不显著,琉璃河、白河下段、汤河上游的健康状况相对较好,潮河中下段和小汤河的健康状况相对较差。流域内不合理的畜禽养殖、岸边带种植及民俗旅游是导致流域生态健康退化的主要原因,建议加强污染负荷排放的控制和监管涉水活动对水生生境的干扰以改善流域健康状况,并重点关注可指示水生态系统早期退化的生物指数,以实现可持续性和适应性的流域管理,保障密云水库的水生态安全。