Mutation of the chloroplast‐localized phosphate transporter OsPHT2;1 reduces flavonoid accumulation and UV tolerance in rice

Phosphorus (P) is an essential macronutrient required for plant development and production. The mechanisms regulating phosphate (Pi) uptake are well established, but the function of chloroplast Pi homeostasis is poorly understood in Oryza sativa (rice). PHT2;1 is one of the transporters/translocators mediating Pi import into chloroplasts. In this study, to gain insight into the role of OsPHT2;1‐mediated stroma Pi, we analyzed OsPHT2;1 function in Pi utilization and photoprotection. Our results showed that OsPHT2;1 was induced by Pi starvation and light exposure. Cell‐based assays showed that OsPHT2;1 localized to the chloroplast envelope and functioned as a low‐affinity Pi transporter. The ospht2;1 had reduced Pi accumulation, plant growth and photosynthetic rates. Metabolite profiling revealed that 52.6% of the decreased metabolites in ospht2;1 plants were flavonoids, which was further confirmed by 40% lower content of total flavonoids compared with the wild type. As a consequence, ospht2;1 plants were more sensitive to UV‐B irradiation. Moreover, the content of phenylalanine, the precursor of flavonoids, was also reduced, and was largely associated with the repressed expression of ADT1/MTR1. Furthermore, the ospht2;1 plants showed decreased grain yields at relatively high levels of UV‐B irradiance. In summary, OsPHT2;1 functions as a chloroplast‐localized low‐affinity Pi transporter that mediates UV tolerance and rice yields at different latitudes.     

The role of astrocytes in oxidative stress of central nervous system: A mixed blessing

Central nervous system (CNS) maintains a high level of metabolism, which leads to the generation of large amounts of free radicals, and it is also one of the most vulnerable organs to oxidative stress. Emerging evidences have shown that, as the key homeostatic cells in CNS, astrocytes are deeply involved in multiple aspects of CNS function including oxidative stress regulation. Besides, the redox level in CNS can in turn affect astrocytes in morphology and function. The complex and multiple roles of astrocytes indicate that their correct performance is crucial for the normal functioning of the CNS, and its dysfunction may result in the occurrence and progression of various neurological disorders. To date, the influence of astrocytes in CNS oxidative stress is rarely reviewed. Therefore, in this review we sum up the roles of astrocytes in redox regulation and the corresponding mechanisms under both normal and different pathological conditions.     

以环境育人为理念的本科教学实验室管理模式探讨

本科教学实验室是开展本科生实验教学的主要场所,如何通过实验室的管理有效提升学生实验素养值得探索。文中主要介绍了将“6S (整理 (Seiri)、整顿 (Seiton)、清扫 (Seiso)、清洁 (Seiketsu)、素养 (Shitsuke)、安全 (Safety) 六项要素) 管理”理念引入本科教学实验室管理的应用实践与效果,特别是实验室环境管理、实验室安全管理、物品定位管理、试剂和耗材管理、学生培训和考核等方面的具体做法。通过实施“6S管理”,实验室环境得以改善,学生的实验素养得到提高,本科实验教学的质量得到改善和提高,达到环境育人的目的。这为高校教学实验室的建设和有效管理提供可推广、可操作的经验。     

罗霄山脉翼手目物种多样性及适生区预测

罗霄山脉位于中国大陆东南部, 是一条南北走向的大型山脉, 面积约6.76万km²。该山脉位于欧亚大陆东部季风区, 生物多样性丰富, 是亚洲东部第三纪冰期动物重要的避难所。为了解罗霄山脉翼手目物种多样性状况, 本研究组于2013-2018年, 使用雾网、手网和竖琴网等工具开展了针对性调查与标本采集, 同时运用形态分类学和分子系统发生学方法鉴定物种。根据调查结果并结合文献记载: 罗霄山脉地区现有翼手目物种4科14属40种, 其中罗霄山脉翼手目新记录种25种, 省级翼手目分布新记录种9种。同时, 本研究基于5年的调查采集位点, 使用生物多样 性与气候变化虚拟实验室(the Biodiversity & Climate Change Virtual Laboratory)在线生境预测平台, 对罗霄山脉翼手目物种当前的适生区, 以及3种不同量温室气体排放情景下(representative concentration pathway, RCP 2.6 / 6.0 / 8.5) 2050年的适生区进行预测, 其中随机森林算法(random forest)的模型解释力较优, 其预测结果显示: 影响该区域翼手目分布的主要环境因子为降水季节性和年平均温度; 山脉中部及南部为翼手目的高适生区, 面积约为罗霄山脉的30%; 与当前适生区相比, RCP 2.6情景下2050年该类群适生区有所扩增, RCP 6.0和RCP 8.5情景下均会导致翼手目适生区急剧缩减, 且分布区将迁移至高海拔区域以响应气候变化。而本项目的开展不仅初步掌握了罗霄山脉翼手目物种多样性本底状况, 也为开展后续的翼手目研究和保护管理提供了参考。     

Estimating the inbreeding level and genetic relatedness in an isolated population of critically endangered Sichuan taimen (Hucho Bleekeri) using genome‐wide SNP markers

Sichuan taimen (Hucho bleekeri) is critically endangered fish listed in The Red List of Threatened Species compiled by the International Union for Conservation of Nature (IUCN). Specific locus amplified fragment sequencing (SLAF‐seq)‐based genotyping was performed for Sichuan taimen with 43 yearling individuals from three locations in Taibai River (a tributary of Yangtze River) that has been sequestered from its access to the ocean for more than 30 years since late 1980s. Applying the inbreeding level and genetic relatedness estimation using 15,396 genome‐wide SNP markers, we found that the inbreeding level of this whole isolated population was at a low level (2.6 × 10^?3 ± 0.079), and the means of coancestry coefficients within and between the three sampling locations were all very low (close to 0), too. Genomic differentiation was negatively correlated with the geographical distances between the sampling locations (p < .001), and the 43 individuals could be considered as genetically independent two groups. The low levels of genomic inbreeding and relatedness indicated a relatively large number of sexually mature individuals were involved in reproduction in Taibai River. This study suggested a genomic‐relatedness‐guided breeding and conservation strategy for wild fish species without pedigree information records.     

Land masses and oceanic currents drive population structure of Heritiera littoralis,a widespread mangrove in the Indo‐West Pacific

Phylogeographic forces driving evolution of sea‐dispersed plants are often influenced by regional and species characteristics, although not yet deciphered at a large spatial scale for many taxa like the mangrove species Heritiera littoralis. This study aimed to assess geographic distribution of genetic variation of this widespread mangrove in the Indo‐West Pacific region and identify the phylogeographic factors influencing its present‐day distribution. Analysis of five chloroplast DNA fragments’ sequences from 37 populations revealed low genetic diversity at the population level and strong genetic structure of H. littoralis in this region. The estimated divergence times between the major genetic lineages indicated that glacial level changes during the Pleistocene epoch induced strong genetic differentiation across the Indian and Pacific Oceans. In comparison to the strong genetic break imposed by the Sunda Shelf toward splitting the lineages of the Indian and Pacific Oceans, the genetic differentiation between Indo‐Malesia and Australasia was not so prominent. Long‐distance dispersal ability of H. littoralis propagules helped the species to attain transoceanic distribution not only across South East Asia and Australia, but also across the Indian Ocean to East Africa. However, oceanic circulation pattern in the South China Sea was found to act as a barrier creating further intraoceanic genetic differentiation. Overall, phylogeographic analysis in this study revealed that glacial vicariance had profound influence on population differentiation in H. littoralis and caused low genetic diversity except for the refugia populations near the equator which might have persisted through glacial maxima. With increasing loss of suitable habitats due to anthropogenic activities, these findings therefore emphasize the urgent need for conservation actions for all populations throughout the distribution range of H. littoralis.     

Effects of long-term antibiotic treatment on mice urinary aromatic amino acid profiles

The gut microbiota–host co-metabolites are good indicators for representing the cross-talk between host and gut microbiota in a bi-direct manner. There is increasing evidence that levels of aromatic amino acids (AAAs) are associated with the alteration of intestinal microbial community though the effects of long-term microbial disturbance remain unclear. Here we monitored the gut microbiota composition and host–microbiota co-metabolites AAA profiles of mice after gentamicin and ceftriaxone treatments for nearly 4 months since their weaning to reveal the relationship between host and microbiome in long- term microbial disturbances. The study was performed employing targeted LC-MS measurement of AAA-related metabolites and 16S RNA sequence of mice cecal contents. The results showed obvious decreased gut microbial diversity and decreased Firmicutes/Bacteroidetes ratio in the cecal contents after long-term antibiotics treatment. The accumulated AAA (tyrosine, phenylalanine and tryptophan) and re-distribution of their downstreaming metabolites that produced under the existence of intestinal flora were found in mice treated with antibiotics for 4 months. Our results suggested that the long-term antibiotic treatment significantly changed the composition of the gut microbiota and destroyed the homeostasis in the intestinal metabolism. And the urinary AAA could be an indicator for exploring interactions between host and gut microbiota.     

Down-regulation of RBP4 indicates a poor prognosis and correlates with immune cell infiltration in hepatocellular carcinoma

Recent research has indicated that metabolically related genes play crucial roles in the pathogenesis of hepatocellular carcinoma (HCC). We evaluated the associations between novel biomarkers and retinol-binding protein 4 (RBP4) for predicting clinical HCC outcomes, hub-related genes, pathway regulation, and immune cells infiltration. Bioinformatic analyses based on data from The Cancer Genome Atlas were performed using online analysis tools. RBP4 expression was low in HCC and was also down-regulated in pan-cancers compared with normal tissues. RBP4 expression was also significantly different based on age (41–60 years old versus 61–80 years old), and low RBP4 expression levels were associated with advanced tumor stages and grades. Higher RBP4 expression was associated with better overall survival time in HCC patients, and we identified a deletion-mutation rate of 1.4% in RBP4. We also identified ten co-expressed genes most related to RBP4 and explored the relationships between six hub genes (APOB, FGA, FGG, SERPINC1, APOA1, and F2) involved in RBP4 regulation. A pathway enrichment analysis for RBP4 indicated complement and coagulation cascades, metabolic pathways, antibiotic biosynthesis pathways, peroxisome proliferator-activated receptor signaling pathways, and pyruvate metabolism pathways. These results suggest that RBP4 may be a novel biomarker for HCC prognosis, and an indicator of low immune response to the disease.