Efficient plant regeneration system for New Guinea Impatiens (Impatiens hawkeri W. Bull) CV. ‘Violet’ and ‘Scarlet Bronze Leaf’

Plant Cell, Tissue and Organ Culture (PCTOC) - New Guinea Impatiens (Impatiens hawkeri W. Bull) is an eye-popping landscaping plant of bright and colorful blooms. A highly efficient in vitro plant...     

A validated stability-indicating HPLC method for the determination of PEGylated puerarin in aqueous solutions

The aim of this study was to develop a validated specific stability-indicating HPLC method for the quantitative determination of PEGylated puerarin (PEG-PUE) in aqueous solutions. The method was validated by subjecting PEG-PUE to forced degradation under stress conditions of acid, alkali, water hydrolysis, and oxidation. Both PEG-PUE and puerarin (PUE) were simultaneously determined and separated on CAPCELL PAK C18 column by gradient elution with 0.2% aqueous phosphoric acid and acetonitrile as the mobile phase. The flow rate was 1.0 mL min⁻¹ and detection wavelength was set at 250 nm. Both calibration curves showed good linear regression (r ≥ 0.9998) within test ranges. The LOD and LOQ of PEG-PUE were determined to be 3 and 9 μg mL⁻¹ respectively. Degradation of PEG-PUE followed pseudo-first-order kinetics with t_1/2 of 59 min at pH 9.0 and 17.79 h at pH 7.4. However, at pH 5.0 and 2.0, there was no significant degradation of PEG-PUE over time. In conclusion, the method was observed to have the necessary specificity, precision, and accuracy, and to be suitable for quantity monitoring the degradation process of PEG-PUE during stability studies. The degradation studies may give insight into useful information for formulation development of PEG-PUE.     

蛋白质二级结构预测服务器PSRSM

蛋白质二级结构预测是蛋白质结构研究的一个重要环节,大量的新预测方法被提出的同时,也不断有新的蛋白质二级结构预测服务器出现。试验选取7种目前常用的蛋白质二级结构预测服务器:PSRSM、SPOT-1D、MUFOLD、Spider3、RaptorX,Psipred和Jpred4,对它们进行了使用方法的介绍和预测效果的评估。随机选取了PDB在2018年8月至11月份发布的180条蛋白质作为测试集,评估角度为:Q3、Sov、边界识别率、内部识别率、转角C识别率,折叠E识别率和螺旋H识别率七种角度。上述服务器180条测试数据的Q3结果分别为:89.96%、88.18%、86.74%、85.77%、83.61%,79.72%和78.29%。结果表明PSRSM的预测结果最好。180条测试集中,以同源性30%,40%,70%分类的实验结果中,PSRSM的Q3结果分别为:89.49%、90.53%、89.87%,均优于其他服务器。实验结果表明,蛋白质二级结构预测可从结合多种深度学习方法以及使用大数据训练模型方向做进一步的研究。     

An investigation of spatial-temporal patterns and predictions of the coronavirus 2019 pandemic in Colombia, 2020–2021

Colombia announced the first case of severe acute respiratory syndrome coronavirus 2 on March 6, 2020. Since then, the country has reported a total of 5,002,387 cases and 127,258 deaths as of October 31, 2021. The aggressive transmission dynamics of SARS-CoV-2 motivate an investigation of COVID-19 at the national and regional levels in Colombia. We utilize the case incidence and mortality data to estimate the transmission potential and generate short-term forecasts of the COVID-19 pandemic to inform the public health policies using previously validated mathematical models. The analysis is augmented by the examination of geographic heterogeneity of COVID-19 at the departmental level along with the investigation of mobility and social media trends. Overall, the national and regional reproduction numbers show sustained disease transmission during the early phase of the pandemic, exhibiting sub-exponential growth dynamics. Whereas the most recent estimates of reproduction number indicate disease containment, with R_t<1.0 as of October 31, 2021. On the forecasting front, the sub-epidemic model performs best at capturing the 30-day ahead COVID-19 trajectory compared to the Richards and generalized logistic growth model. Nevertheless, the spatial variability in the incidence rate patterns across different departments can be grouped into four distinct clusters. As the case incidence surged in July 2020, an increase in mobility patterns was also observed. On the contrary, a spike in the number of tweets indicating the stay-at-home orders was observed in November 2020 when the case incidence had already plateaued, indicating the pandemic fatigue in the country.     

Acrolein,an endogenous aldehyde induces synaptic dysfunction in vitro and in vivo: Involvement of RhoA/ROCK2 pathway

Acrolein, an unsaturated aldehyde, is increased in the brain of Alzheimer''s disease (AD) patients and identified as a potential inducer of sporadic AD. Synaptic dysfunction, as a typical pathological change occurring in the early stage of AD, is most closely associated with the severity of dementia. However, there remains a lack of clarity on the mechanisms of acrolein inducing AD‐like pathology and synaptic impairment. In this study, acrolein‐treated primary cultured neurons and mice were applied to investigate the effects of acrolein on cognitive impairment and synaptic dysfunction and their signaling mechanisms. In vitro, ROCK inhibitors, Fasudil, and Y27632, could attenuate the axon ruptures and synaptic impairment caused by acrolein. Meanwhile, RNA‐seq distinct differentially expressed genes in acrolein models and initially linked activated RhoA/Rho‐kinase2 (ROCK2) to acrolein‐induced synaptic dysfunction, which could regulate neuronal cytoskeleton and neurite. The Morris water maze test and in vivo field excitatory postsynaptic potential (fEPSP) were performed to evaluate spatial memory and long‐term potential (LTP), respectively. Acrolein induced cognitive impairment and attenuated LTP. Furthermore, the protein level of Synapsin 1 and postsynaptic density 95 (PSD95) and dendritic spines density were also decreased in acrolein‐exposed mice. These changes were improved by ROCK2 inhibitor Fasudil or in ROCK2^+/− mice. Together, our findings suggest that RhoA/ROCK2 signaling pathway plays a critical role in acrolein‐induced synaptic damage and cognitive dysfunction, suggesting inhibition of ROCK2 should benefit to the early AD.     

A perovskite-based electrochemiluminescence aptasensor for tetracycline screening

Tetracyclines are currently the most commonly used class of antibiotics, and their residue issue significantly impacts public health safety. In this study, a surface modification of perovskite with cetyltrimethylammonium bromide led to the generation of stable electrochemiluminescence (ECL) emitters in aqueous systems and improved the biocompatibility of perovskite. A perovskite quantum dot-based ECL sensing strategy was developed. Utilizing the corresponding aptamer of the antibiotics, strain displacement reactions were triggered, disrupting the ECL quenching system composed of perovskite and Ag nanoclusters (Ag NCs) on the electrode surface, generating a signal to achieve quantitative detection of several common tetracycline antibiotics. The perovskite quantum dot provided a strong and stable initial signal, while the efficient catalytic activity of the silver cluster enhanced the recognition sensitivity. Tetracycline, chlortetracycline, and oxytetracycline were used as examples to demonstrate the differentiation and quantitative detection through this method. In addition, the aptasensor exhibited analytical performance with the linear range (0.1–10 μM OTC) and good recovery rates of 94.7% to 101.6% in real samples. This approach has the potential to become a sensitive and practical approach for assessing antibiotic residues.     

泛素E3连接酶接头蛋白SPOP和MDM2在DNA损伤修复中的作用

DNA损伤修复是维持细胞基因组稳定性和完整性的基础,越来越多的研究发现,E3泛素连接酶在DNA损伤修复中起着重要的作用.该文将介绍DNA损伤修复的机制、DNA损伤修复与疾病的关系、及E3泛素连接酶接头蛋白MDM2和SPOP在DNA损伤修复中的作用.重点围绕DNA损伤修复的两条通路:E3泛素连接酶接头蛋白SPOP与ATM...     

响应面法优化黑曲霉固定化条件及其对土壤中溴氰菊酯的降解特性研究

【目的】通过研究吸附包埋法固定黑曲霉(Aspergillus niger)的最佳制备工艺,初步探讨固定化黑曲霉对溴氰菊酯(deltamethrin, DM)及其中间产物3-苯氧基苯甲酸(3-phenoxybenzoic acid,3-PBA)的降解机制,并将其应用于农业种植中以评价固定化黑曲霉的实际应用效果。【方法】以生物炭、海藻酸钠为固定化载体,通过单因素和响应面试验对固定化黑曲霉(immobilized Aspergillusniger)的制备工艺进行优化。同时,利用高效液相色谱法分析DM和3-PBA的含量变化。【结果】海藻酸钠浓度、生物炭浓度和菌液接种量为DM去除率的显著影响因子,当三者分别为25.27、1.28和125.28 g/L时,是黑曲霉固定化的最佳制备条件;在施加固定化黑曲霉后,土壤中DM半衰期由7.6d缩短至5.2d,黑曲霉对3-PBA也具有降解作用,在21h达到最低浓度1.45mg/kg;修复后的土壤可显著提高番茄种子发芽率,株高、根长等6个生长指标较DM单独处理组也有不同程度的恢复;在经固定化黑曲霉修复28 d后,污染土壤根系酶活和微生物数量均得到不同程度改善。【...     

山矾花精油化学成分的研究

用ＧＣ／ＭＳ从山矾花精油中鉴定出６８个化合物。主要芳香成分为方樟醇１８．３５％;反式－氧化芳樟醇（吡喃型）４．５６％顺式－氧化方樟醇１．４０％：β－紫罗兰酮１．２２％;反式－氧化方樟醇０．９５％;顺式－氧化芳樟醇〔吡喃型）０．５３％：γ－癸内酯０．０５％;δ－癸内酯０．１１％二氢－β－紫罗兰酮０．１１％、四氢－β－紫罗兰酮０．０６％．