湘中、湘东地区早籼稻耐土壤潜育性评价

我国南方稻区的主要低产稻田是潜育性稻田,约有一亿亩。挖掘其“潜在生产力”,种植耐潜育性土壤逆境胁迫能力较强的水稻品种,则是简便、经济而有效的重要途径之一。本文就几个早籼稻品种(组合)对潜育性稻田的生态适应性进行了较系统的观测,并初步提出了耐潜育性的几个鉴定指标,诸如根系生长量和幼穗分化期根系氧化力;分蘖早期茎蘖增长速率;分蘖后期单株干物质产量;乳熟期剑叶片过氧化氢酶活性GDI和光合强度等。上述鉴定指标,综合应用于水稻品种生态适应性和耐潜育性育种研究,有助于提高水稻抗逆性育种的效率。     

城市森林碳汇及其抵消能源碳排放效果——以广州为例

城市森林及其管理相关政策作为减少CO₂排放的有效策略得到了较为广泛的关注。采用材积源生物量方程与净初级生产力方法来定量分析了广州市城市森林碳储量和碳固定量,根据化石能源使用量及其碳排放因子核算了广州城市能源碳排放,最后评估了城市森林碳抵消效果。结果显示广州市城市森林碳储量为654.42×10⁴t,平均碳密度为28.81 t/hm²,而森林碳固定量为658732 t/a,平均固碳率为2.90 t·hm^-2·a^-1。2005-2010年广州市年均能源碳排放则达到2907.41×10⁴t。广州城市森林碳储量约为城市年均能源碳排放的22.51%,其通过碳固定年均能够抵消年均碳排放的2.27%,不过从城市森林综合效益来看其仍是城市低碳发展重要举措之一。分析了林型组成和林龄结构对于广州森林碳储量和碳固定量的影响,并从森林管理角度为城市森林碳汇提升提出建议。这些结果和讨论有助于评估城市森林碳汇在抵消碳排放中所起的效果。     

Development and validation of immune inflammation–based index for predicting the clinical outcome in patients with nasopharyngeal carcinoma

Inflammation indicators, such as systemic inflammation response index (SIRI), systemic immune‐inflammation index (SII), neutrophil‐to‐lymphocyte ratio (NLR) and platelet‐lymphocyte ratio (PLR), are associated with poor prognosis in various solid cancers. In this study, we investigated the predictive value of these inflammation indicators in nasopharyngeal carcinoma (NPC). This retrospective study involved 559 patients with NPC and 500 patients with chronic rhinitis, and 255 NPC patients were followed up successfully. Continuous variables and qualitative variables were measured by t test and chi‐square test, respectively. The optimal cut‐off values of various inflammation indicators were determined by receiver operating characteristic (ROC) curve. Moreover, the diagnostic value for NPC was decided by the area under the curves (AUCs). The Kaplan‐Meier methods and the log‐rank test were used to analyse overall survival (OS) and disease‐free survival (DFS). The independent prognostic risk factors for survival and influencing factors of side effects after treatment were analysed by Cox and logistic regression analysis, respectively. Most haematological indexes of NPC and rhinitis were significantly different between the two groups, and PLR was optimal predictive indicators of diagnosis. In the multivariable Cox regression analysis, PLR, WBC, RDW, M stage and age were independent prognostic risk factors. Many inflammation indicators that affected various side effects were evaluated by logistic regression analysis. In conclusion, the combined inflammation indicators were superior to single haematological indicator in the diagnosis and prognosis of NPC. These inflammation indicators can be used to supply the current evaluation system of the TNM staging system to help predict the prognosis in NPC patients.     

The use of SARS-CoV-2-related coronaviruses from bats and pangolins to polarize mutations in SARS-Cov-2

正Dear Editor,The coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 coronavirus has become a global pandemic.The SARS-CoV-2 genome has a similarity of 96.2%to that of RaTG13, a bat SARS-CoV-2-related coronavirus detected in Rhinolophus affinis (Paraskevis et al., 2020; Zhou et al.,2020). The SARS-CoV-2 genome also has 85.5%-92.4%     

Synthesis of High Aspect Ratio BaTiO3 Nanowires for High Energy Density Nanocomposite Capacitors

High energy density capacitors are critically important in advanced electronic devices and power systems since they can reduce the weight, size and cost required to meet a desired application. Nanocomposites hold strong potential for increasing the performance of high power energy sources; however, the energy density of most nanocomposites is still low compared to commercial capacitors and neat polymers. Here, we develop a new synthesis method for the growth of high aspect ratio barium titanate nanowires (BaTiO₃) nanowires (NWs) with high yield. High energy density nanocomposite capacitors are fabricated using surface‐functionalized high aspect ratio BaTiO₃ NWs in a poly(vinylidene fluoride‐trifluoroethylene‐chlorofluoroethylene) (P(VDF‐TrFE‐CFE)) matrix. At a 17.5% volume fraction, the nanocomposites show more than 45.3% increase in energy density above that of the pure P(VDF‐TrFE‐CFE) polymer (10.48 J/cc compared to 7.21 J/cc) at electric field 300 MV/m. This value is significant and exceeds those reported for the conventional polymer‐ceramic nanocomposites; it is also more than seven times larger than high performance commercial polypropylene capacitor (1.2 J/cc at 640 MV/m). In addition, our nanocomposite capacitor has a maximum power density as high as 1.2 MW/cc occurring only 1.52 μs after the start of discharge. The findings of this research could lead to enhanced interest in nanowires based nanocomposites due to their potential for achieving next generation energy storage devices.     

ompC突变造成大肠杆菌在碱性条件下对渗透压敏感

大肠杆菌DH42突变株碱性条件下对高渗透压敏感。采用mini-Tn5转座突变质粒,同源重组构建突变菌株和DNA片段亚克隆等技术确定了造成大肠杆菌DH42在碱性条件下,对高渗透压敏感的原因是ompC基因突变。通过P1转导,构建了大肠杆菌D9（W3110 ompC：：kan）菌株。比较D9菌株和DH42菌株在不同pH和不同盐浓度条件下的生长,发现大肠杆菌ompC基因是大肠杆菌在碱性条件下应对高渗透压环境胁迫的必须基因。     

Characterizing mobile element insertions in 5675 genomes

Mobile element insertions (MEIs) are a major class of structural variants (SVs) and have been linked to many human genetic disorders, including hemophilia, neurofibromatosis, and various cancers. However, human MEI resources from large-scale genome sequencing are still lacking compared to those for SNPs and SVs. Here, we report a comprehensive map of 36 699 non-reference MEIs constructed from 5675 genomes, comprising 2998 Chinese samples (∼26.2×, NyuWa) and 2677 samples from the 1000 Genomes Project (∼7.4×, 1KGP). We discovered that LINE-1 insertions were highly enriched in centromere regions, implying the role of chromosome context in retroelement insertion. After functional annotation, we estimated that MEIs are responsible for about 9.3% of all protein-truncating events per genome. Finally, we built a companion database named HMEID for public use. This resource represents the latest and largest genomewide study on MEIs and will have broad utility for exploration of human MEI findings.     

Histone acetyltransferase general control non‐repressed protein 5 (GCN5) affects the fatty acid composition of Arabidopsis thaliana seeds by acetylating fatty acid desaturase3 (FAD3)

Seed oils are important natural resources used in the processing and preparation of food. Histone modifications represent key epigenetic mechanisms that regulate gene expression, plant growth and development. However, histone modification events during fatty acid (FA) biosynthesis are not well understood. Here, we demonstrate that a mutation of the histone acetyltransferase GCN5 can decrease the ratio of α‐linolenic acid (ALA) to linoleic acid (LA) in seed oil. Using RNA‐Seq and ChIP assays, we identified FAD3, LACS2, LPP3 and PLAIIIβ as the targets of GCN5. Notably, the GCN5‐dependent H3K9/14 acetylation of FAD3 determined the expression levels of FAD3 in Arabidopsis thaliana seeds, and the ratio of ALA/LA in the gcn5 mutant was rescued to the wild‐type levels through the overexpression of FAD3. The results of this study indicated that GCN5 modulated FA biosynthesis by affecting the acetylation levels of FAD3. We provide evidence that histone acetylation is involved in FA biosynthesis in Arabidopsis seeds and might contribute to the optimization of the nutritional structure of edible oils through epigenetic engineering.     

Effect of CDKN2A/B rs4977756 polymorphism on glioma risk: a meta-analysis of 16 studies including 24077 participants

So far, epidemiological studies have been performed to investigate the association of CDKN2A/B rs4977756 polymorphism and glioma risk. However, the results from different studies remain inconsistent. To clarify these conflicts and to quantitatively evaluate the effect of rs4977756 polymorphism on glioma risk, a meta-analysis was conducted using relevant published clinical studies about rs4977756 polymorphisms and glioma risk. Relevant studies concerning the association between rs4977756 polymorphism and risk of glioma were included in this meta-analysis. Odds ratio (OR) and 95 % confidence interval (CI) were calculated under fixed or random effects models when appropriate. Subgroup analyses were performed by race. This meta-analysis included 13 studies with a total of 8129 cases and 15,858 controls. The pooled results showed that there was an obvious association of CDKN2A/B rs4977756 polymorphism with risk of glioma in all four comparison models (dominant model/AG + GG vs. AA: OR = 1.36, 95 %CI = 1.20–1.54, p < 0.01; heterozygote comparison/AG vs. AA: OR = 1.31, 95 %CI = 1.12–1.53, p < 0.01; homozygote comparison/GG versus AA: OR = 1.49, 95 %CI = 1.36–1.64, p < 0.01; additive model/G vs. A: OR = 1.23, 95 %CI = 1.18–1.28, p < 0.01, respectively). For the subgroup analyses of ethnicities, similar results were observed in Caucasians. However, the association was not found between rs4977756 polymorphism and the risk of glioma in all models for the Asian studies. The CDKN2A/B rs4977756 polymorphism is obvious increase the risk of glioma in Caucasians. Future studies are needed to confirm the results in other ethnic populations.