Associations between leaf developmental stability,variability, canalization,and phenotypic plasticity in Abutilon theophrasti

Developmental stability, canalization, and phenotypic plasticity are the most common sources of phenotypic variation, yet comparative studies investigating the relationships between these sources, specifically in plants, are lacking. To investigate the relationships among developmental stability or instability, developmental variability, canalization, and plasticity in plants, we conducted a field experiment with Abutilon theophrasti, by subjecting plants to three densities under infertile vs. fertile soil conditions. We measured the leaf width (leaf size) and calculated fluctuating asymmetry (FA), coefficient of variation within and among individuals (CV_intra and CV_inter), and plasticity (PI_rel) in leaf size at days 30, 50, and 70 of plant growth, to analyze the correlations among these variables in response to density and soil conditions, at each of or across all growth stages. Results showed increased density led to lower leaf FA, CV_intra, and PI_rel and higher CV_inter in fertile soil. A positive correlation between FA and PI_rel occurred in infertile soil, while correlations between CV_inter and PI_rel and between CV_inter and CV_intra were negative at high density and/or in fertile soil, with nonsignificant correlations among them in other cases. Results suggested the complexity of responses of developmental instability, variability, and canalization in leaf size, as well as their relationships, which depend on the strength of stresses. Intense aboveground competition that accelerates the decrease in leaf size (leading to lower plasticity) will be more likely to reduce developmental instability, variability, and canalization in leaf size. Increased developmental instability and intra‐ and interindividual variability should be advantageous and facilitate adaptive plasticity in less stressful conditions; thus, they are more likely to positively correlate with plasticity, whereas developmental stability and canalization with lower developmental variability should be beneficial for stabilizing plant performance in more stressful conditions, where they tend to have more negative correlations with plasticity.     

Experiments on Nitrogen and Phosphorus Release by Chironomus ex gr. plumosus from the Sediments of Lake Balaton,Hungary

Sediment-water systems of Lake Balaton mud and tap water were constructed in plexiglass tubes and boxes for evaluation of changes in the nitrogen and phosphorus contents of overlying water as influenced by chironomid density and light conditions. Nitrogen flux from sediment was greatly influenced by denitrification process. The amount of TN released by chironomids amounted to about half of the yearly nitrogen fixation rate in Lake Balaton. Omnivorous chironomids increased the phosphorus content of the overlying water. The rate of release was density dependent. TP release rates ranged between 1–17 mg m⁻² day ⁻¹ over a range of densities 500–20,000 larvae m⁻². It became evident that aerobic sediment cores can be an important nutrient source in lakes where chironomids inhabit them at densities above 1,000 larvae m⁻².     

Amino acid starvation‐induced LDLR trafficking accelerates lipoprotein endocytosis and LDL clearance

Mammalian cells utilize Akt‐dependent signaling to deploy intracellular Glut4 toward cell surface to facilitate glucose uptake. Low‐density lipoprotein receptor (LDLR) is the cargo receptor mediating endocytosis of apolipoprotein B‐containing lipoproteins. However, signaling‐controlled regulation of intracellular LDLR trafficking remains elusive. Here, we describe a unique amino acid stress response, which directs the deployment of intracellular LDLRs, causing enhanced LDL endocytosis, likely via Ca²⁺ and calcium/calmodulin‐dependent protein kinase II‐mediated signalings. This response is independent of induction of autophagy. Amino acid stress‐induced increase in LDL uptake in vitro is comparable to that by pravastatin. In vivo, acute AAS challenge for up to 72 h enhanced the rate of hepatic LDL uptake without changing the total expression level of LDLR. Reducing dietary amino acids by 50% for 2 to 4 weeks ameliorated high fat diet‐induced hypercholesterolemia in heterozygous LDLR‐deficient mice, with reductions in both LDL and VLDL fractions. We suggest that identification of signaling‐controlled regulation of intracellular LDLR trafficking has advanced our understanding of the LDLR biology, and may benefit future development of additional therapeutic strategies for treating hypercholesterolemia.     

基于单细胞转录组的多级别胶质瘤异质性及免疫微环境分析揭示了潜在的预后生物标志物

脑胶质瘤(glioma)是中枢神经系统最常见的内在肿瘤,具有发病率高、预后较差等特点。本研究旨在鉴定多形性胶质母细胞瘤(glioblastoma multiforme,GBM)和低级别胶质瘤(lower-grade gliomas, LGG)之间的差异表达基因(differentially expressed genes, DEGs),以探讨不同级别胶质瘤的预后影响因素。从NCBI基因表达综合数据库中收集了胶质瘤的单细胞转录组测序数据,其中包括来自3个数据集的共29 097个细胞样本。对于不同分级的人脑胶质瘤进行分析,经过滤得到21 071个细胞,通过基因本体分析、京都基因与基因组百科全书途径分析,从差异表达基因中筛选出70个基因,我们通过查阅文献,聚焦到delta样典型Notch配体3 (delta like canonical Notch ligand 3,DLL3)这个基因。基于TCGA的基因表达谱交互分析(gene expression profiling interactive analysis, GEPIA)数据库用于探索LGG和GBM中DLL3基因的表达差异,采用基因表达...     

Specificity of mRNA Folding and Its Association with Evolutionarily Adaptive mRNA Secondary Structures

The secondary structure is a fundamental feature of both non-coding RNAs (ncRNAs) and messenger RNAs (mRNAs). However, our understanding of the secondary structures of mRNAs, especially those of the coding regions, remains elusive, likely due to translation and the lack of RNA-binding proteins that sustain the consensus structure like those binding to ncRNAs. Indeed, mRNAs have recently been found to adopt diverse alternative structures, but the overall functional significance remains untested. We hereby approach this problem by estimating the folding specificity, i.e., the probability that a fragment of an mRNA folds back to the same partner once refolded. We show that the folding specificity of mRNAs is lower than that of ncRNAs and exhibits moderate evolutionary conservation. Notably, we find that specific rather than alternative folding is likely evolutionarily adaptive since specific folding is frequently associated with functionally important genes or sites within a gene. Additional analysis in combination with ribosome density suggests the ability to modulate ribosome movement as one potential functional advantage provided by specific folding. Our findings reveal a novel facet of the RNA structurome with important functional and evolutionary implications and indicate a potential method for distinguishing the mRNA secondary structures maintained by natural selection from molecular noise.     

Phenotypes and environment predict seedling survival for seven co‐occurring Great Basin plant taxa growing with invasive grass

Trait–environment correlations can arise from local adaptation and can identify genetically and environmentally appropriate seeds for restoration projects. However, anthropogenic changes can disrupt the relationships between traits and fitness. Finding the best seed sources for restoration may rely on describing plant traits adaptive in disturbed and invaded environments, recognizing that while traits may differ among species and functional groups, there may be similarities in the strategies that increase seedling establishment. Focusing on three grass genera, two shrub species, and two forb genera, we collected seeds of all taxa from 16 common sites in the sagebrush steppe of the western United States. We measured seed and seedling characteristics, including seed size, emergence timing, and root and shoot traits, and compiled a suite of environmental variables for each collection site. We described trait–environment associations and asked how traits or environment of origin were associated with seedling survival in invaded gardens. Sampling seven taxa from the same sites allowed us to ask how trait–environment–performance associations differ among taxa and whether natural selection favors similar traits across multiple taxa and functional groups. All taxa showed trait–environment associations consistent with local adaptation, and both environment of origin and phenotypes predicted survival in competitive restoration settings, with some commonalities among taxa. Notably, rapid emergence and larger seeds increased survival for multiple taxa. Environmental factors at collection sites, including lower slopes (especially for grasses), greater mean annual temperatures (especially for shrubs and forbs), and greater precipitation seasonality were frequently associated with increased survival. We noted one collection site with high seedling survival across all seven taxa, suggesting that conditions within some sites may result in selection for traits that increase establishment for multiple species. Thus, choosing native plant sources with the most adaptive traits, along with matching climates, will likely improve the restoration of invaded communities.     

2型糖尿病合并骨质疏松症患者外周血炎性因子表达与骨代谢、骨密度丢失的关系

摘要 目的：探讨2型糖尿病合并骨质疏松症患者外周血中炎性因子NLR、IL-1β、TNF-α与骨代谢指标骨密度、活性维生素D、PTH、ALP及生化指标FPG、2hPG、HbA1c、空腹C肽、BMI、血脂、血尿酸之间的关系,为该类患者的诊断和治疗提供参考。方法：选取2020年9月至2021年9月在本院内分泌科就诊的2型糖尿病合并骨质疏松症患者80例作为观察组,同时选取同期健康体检者80例作为对照组。比较两组患者的一般资料,采用ELISA法检测两组患者外周血中NLR、IL-1β、TNF-α的水平,采用双能X线吸收法（DEXA）检测两组患者的骨密度,采用放射免疫法检测两组患者外周血中活性维生素D、PTH的水平,采用生化分析仪检测两组患者外周血中ALP、FPG、2hPG、HbA1c、空腹C肽、BMI、血脂、血尿酸的水平。结果：观察组患者外周血中NLR、IL-1β、TNF-α的水平均高于对照组（P<0.05）,观察组患者骨密度低于对照组（P<0.05）,观察组患者外周血中活性维生素D水平低于对照组（P<0.05）,观察组患者外周血中PTH水平高于对照组（P<0.05）,观察组患者外周血中ALP水平高于对照组（P<0.05）,观察组患者外周血中FPG、2hPG、HbA1c水平高于对照组（P<0.05）,观察组患者空腹C肽水平低于对照组（P<0.05）,观察组患者BMI高于对照组（P<0.05）,观察组患者血脂异常率高于对照组（P<0.05）,观察组患者血尿酸水平高于对照组（P<0.05）。观察组患者外周血中NLR、IL-1β、TNF-α与骨密度呈负相关（P<0.05）,与活性维生素D呈负相关（P<0.05）,与PTH、ALP呈正相关（P<0.05）,与FPG、2hPG、HbA1c、空腹C肽、BMI、血脂、血尿酸无显著相关性（P>0.05）。结论：2型糖尿病合并骨质疏松症患者外周血中炎性因子NLR、IL-1β、TNF-α水平升高,可能与骨代谢紊乱和骨密度丢失有关,提示该类患者存在慢性低度炎症状态,应加强对其骨代谢和骨密度的监测和干预,以降低骨折风险和改善生活质量。     

短期增温和降水减少对半干旱沙质草地群落特征的影响

【目的】为探究短期增温和降水减少对沙质草地植物群落物种多样性、功能性状及生产力的影响,进一步揭示沙质草地植物群落特征对气候变化的响应。【方法】以科尔沁沙质草地植物群落为研究对象,利用开顶式生长室(OTC)模拟增温,研究降水减少0%、20%、40%和60%与增温的交互作用对沙质草地群落组成、物种多样性和功能性状的影响及群落特征与环境因子关系。【结果】结果显示:（1）短期增温和降水减少使沙质草地植物群落组成和物种优势度发生变化,其中优势物种猪毛蒿和达乌里胡枝子在短期增温和降水减少处理下均明显降低,短期增温和降水减少均显著降低了植物群落盖度和地上生物量。（2）短期增温显著降低了Margalef丰富度指数、Simpson指数、Shannon多样性指数和Pielou均匀度指数,短期降水减少对沙质草地供试4种物种多样性指标均无显著影响。（3）短期增温显著提高了植物群落高度和叶干物质含量,显著降低叶厚度,短期降水减少显著提高了叶干物质含量和叶厚度,显著降低了植株高度和比叶面积。（4）短期增温是影响沙质草地物种多样性和功能性状的主要环境因素。【结论】综上可知,短期增温和降水减少改变了沙质草地群落特征,温度是影响沙质草地群落特征的主要环境因子。     

广东海丰紫水鸡种群密度调查

2005年12月~2006年6月对广东海丰公平大湖保护区的紫水鸡(Porphyrio porphyrio)种群密度进行了调查。繁殖期和非繁殖期的种群密度分别为13.33只/km2和9.33只/km2。通过对大湖和东关联安围总的样线平均个体数比较,差异性显著(P<0.05);在种群密度上,发现东关联安围不同时期的种群密度均较高,分别达16.11只/km2和11.67只/km2,大湖分别为9.17只/km2和5.83只/km2。对种群影响因素分析表明,非法猎捕和栖息地质量下降是导致紫水鸡种群变化的重要原因。