A facile fluorescence turn-on biosensor customized for monitoring of protein kinase activity based on carboxylic carbon nanoparticle–peptide complexes

In this study, we present a facile and low-cost approach for detecting protein kinase A (PKA) by assembling a purpose-designed carboxyfluorescein (FAM)-labelled peptide with carboxylic carbon nanoparticles (CNPs). Fluorescence of the FAM-labelled peptide gradually decreases to a low background signal as a result of the electron transfer from CNPs to FAM-labelled peptide via the peptide, which acts as a bridge. The reaction in the sensor in the presence of adenosine 5′-triphosphate and PKA phosphorylates the substrate peptide and disrupts the electrostatic repulsive force between the CNPs and the peptide, therefore altering the spectroscopic signal of the system. The change in fluorescence signal was directly proportional to the PKA concentration in the range 0–1.8 U/ml with a detection limit of 0.04 U/ml. These results suggest that PKA activity can be effectively measured using the developed PKA biosensor. Moreover, the fluorescence biosensor was successfully used in the investigation of PKA in spiked human embryonic kidney (HEK) 293 cells lysates, indicating its potential applications in protein kinase-related biochemical fundamental research.     

Peptide probes containing a non-hydrolyzable phosphotyrosine-mimetic residue for enrichment of protein tyrosine phosphatases

We developed peptide probes containing a non-hydrolyzable phosphotyrosine mimetic, 4-[difluoro(phosphono)methyl]-L-phenylalanine (F₂Pmp) for the enrichment of protein tyrosine phosphatases (PTPs). We found that different F₂Pmp probes can enrich different PTPs, depending on the probe sequence. Furthermore, proteins containing a Src homology 2 (SH2) domain were enriched together. Importantly, probes containing phosphotyrosine instead of F₂Pmp failed to enrich PTPs due to dephosphorylation during the pulldown step. This enrichment approach using peptides containing F₂Pmp could be a generic tool for tyrosine phosphatome analysis without the use of antibodies.     

血清脑钠肽、超敏C反应蛋白、可溶性ST2对阵发性心房颤动患者射频消融术后复发的预测价值研究

摘要 目的：探讨血清脑钠肽（BNP）、超敏C反应蛋白（hs-CRP）、可溶性致瘤抑制素2（sST2）对阵发性心房颤动（AF）患者射频消融（RFA）术后复发的预测价值。方法：选择2016年1月至2020年12月我院收治的接受RFA术治疗的82例阵发性AF患者,术后随访12个月,根据术后是否复发分为复发组（25例）和未复发组（57例）。检测患者血清BNP、hs-CRP、sST2水平,收集临床相关资料,采用多因素Logistic回归模型分析影响阵发性AF患者RFA术后复发的因素,采用受试者工作特征（ROC）曲线分析血清BNP、hs-CRP、sST2预测阵发性AF患者RFA术后复发的价值。结果：复发组血清BNP、hs-CRP、sST2水平高于未复发组（P＜0.05）。血清BNP、hs-CRP、sST2水平升高、AF病程增长是影响阵发性AF患者RFA术后复发的危险因素（P＜0.05）。血清BNP、hs-CRP、sST2预测阵发性AF患者消融术后复发的曲线下面积分别为0.720、0.694、0.718,联合三者预测阵发性AF患者RFA术后复发的曲线下面积为0.866,高于BNP、hs-CRP、sST2单独预测。结论：阵发性AF患者血清BNP、hs-CRP、sST2水平升高是RFA术后复发的危险因素,联合检测血清BNP、hs-CRP、sST2水平有助于预测阵发性AF患者RFA术后复发。     

Mendelian randomization analysis of the causal impact of body mass index and waist-hip ratio on rates of hospital admission

We analyze how measures of adiposity – body mass index (BMI) and waist hip ratio (WHR) – causally influence rates of hospital admission. Conventional analyses of this relationship are susceptible to omitted variable bias from variables that jointly influence both hospital admission and adipose status. We implement a novel quasi-Poisson instrumental variable model in a Mendelian randomization framework, identifying causal effects from random perturbations to germline genetic variation. We estimate the individual and joint effects of BMI, WHR, and WHR adjusted for BMI. We also implement multivariable instrumental variable methods in which the causal effect of one exposure is estimated conditionally on the causal effect of another exposure. Data on 310,471 participants and over 550,000 inpatient admissions in the UK Biobank were used to perform one-sample and two-sample Mendelian randomization analyses. The results supported a causal role of adiposity on hospital admissions, with consistency across all estimates and sensitivity analyses. Point estimates were generally larger than estimates from comparable observational specifications. We observed an attenuation of the BMI effect when adjusting for WHR in the multivariable Mendelian randomization analyses, suggesting that an adverse fat distribution, rather than a higher BMI itself, may drive the relationship between adiposity and risk of hospital admission.     

印度藏茴香植物精油对温室棉蚜的熏蒸毒性及其成分分析（英文）

【目的】棉蚜Aphis gossypii是世界各地室内和室外果树、蔬菜和观赏植物上最具危害性的害虫之一。这一害虫取食植物汁液,产生蜜露,传播植物病毒,对植物从质和量上产生破坏。为了控制温室中的这一害虫,植物精油可用作化学农药的替代药物。本实验研究了印度藏茴香Carum copticum植物精油对棉蚜成虫的熏蒸毒性。【方法】将研磨的印度藏茴香干种子用改良的挥发油提取器(Clevenger-type apparatus)进行水蒸馏。所有生物测定均在27±2℃,相对湿度65%±5%和光周期16L∶8D条件下进行。研究采用完全随机设计,6个处理(5个不同浓度的精油加对照)。每一浓度3次重复,每一重复20头成虫。【结果】结果表明,棉蚜成蚜接触印度藏茴香精油24 h后出现明显的死亡。该精油对棉蚜成蚜的致死中浓度(LC50)为1.21μL/L空气。棉蚜成蚜的死亡百分率对精油的施用表现出较高的敏感性。精油浓度为1.21μL/L空气时,估计的棉蚜的致死中时(LT50)为11.79 h。这一精油的熏蒸毒性与浓度和接触时间之间具有一定的相关性。GC/MS组分分析结果表明,该精油由18种化合物组成,最重要的是一些化合物引起了熏蒸毒性,如麝香草酚(占50.07%)、γ-萜品烯(占23.99%)和对异丙基苯甲烷(占22.90%)。【结论】本研究结果表明印度藏茴香植物精油对棉蚜具有较好的杀虫效果。印度藏茴香精油对棉蚜产生较大的影响,由于它具有较高的熏蒸毒性潜力,因此可在温室中用于这一害虫的综合治理。     

基于质谱技术筛选差异表达蛋白的统计学策略研究进展

随着质谱技术的快速发展,蛋白质组学已成为继基因组学、转录组学之后的又一研究热点,寻找可靠的差异表达蛋白对于生物标记物的发现至关重要.因此,如何准确、灵敏地筛选出差异蛋白已成为基于质谱的定量蛋白质组学的主要研究内容之一.目前,针对该问题的研究方法众多,但这些方法策略的适用范围不尽相同.总体来说,基于质谱技术筛选差异蛋白的统计学策略可以分为3类:基于经典统计学派的策略、基于贝叶斯学派的统计检验策略和其他策略,这3类方法有各自的应用范围、特点及不足.此外,筛选过程还将产生部分假阳性结果,可以采用其他方法对差异表达蛋白的质量进行控制,以提高统计检验结果的可靠性.     

黄粉虫抗菌肽的提取及其生化特性的研究

【目的】测定黄粉虫Tenebrio molitor Linnaeus幼虫抗菌肽提取液的浓度、抑菌活性及其部分生化特性和凝血效应。【方法】本实验用浓度为1×108 CFU/m L大肠杆菌Escherichia coli诱导5龄黄粉虫幼虫,分别在诱导12、24、36、48、60和72 h后提取其中的抗菌肽,并用考马斯亮兰法测定抗菌肽粗提液蛋白的浓度,并用滤纸片法测定其抑菌活性,同时对其热稳定性、反复冻融稳定性、蛋白酶稳定性及不同p H对其活性的影响等生化特性及凝血效应进行了探究。【结果】经大肠杆菌诱导的黄粉虫抗菌肽粗提液的蛋白浓度均显著高于未诱导的黄粉虫组(P<0.01),且在诱导48 h时产生的抗菌肽提取液蛋白的浓度最高,产生的抑菌圈直径也显著高于未诱导的黄粉虫组(P<0.05),生化特性的测定结果显示,黄粉虫抗菌肽有较好的热稳定性、酶稳定性及酸碱稳定性,反复冻溶后对其抑菌活性影响不大,并且无凝血效应。【结论】大肠杆菌可以刺激黄粉虫的免疫系统,增加抗菌肽的表达量,使其产生浓度高、活性强的抗菌肽,且生化特性较稳定。本研究对黄粉虫抗菌肽作为绿色抗生素用于畜牧养殖业的进一步开发与利用提供了科学的理论依据。     

吴茱萸次碱软膏对小鼠尾部鳞片银屑病模型的治疗作用

目的：吴茱萸次碱（Rutaecarpa RUT）是芸香科植物吴茱萸的主要成分,它可激活辣椒素受体促进降钙素基因相关肽（CGRP） 等神经递质的释放来发挥药理作用。本实验的目的为观察吴茱萸次碱软膏对小鼠银屑病模型治疗作用。方法：通过药剂学方法制 成了不同浓度（2%, 5%, 10%）RUT 软膏,在小鼠尾部与背部银屑病模型给药14 天,观察小鼠尾部颗粒层形成的变化,给药结束后 取小鼠背部皮肤组织匀浆后采用放射免疫方法检测CGRP水平变化,并且取小鼠血浆检测CGRP水平变化。结果：不同浓度的吴 茱萸次碱软膏均能促进小鼠尾部颗粒层形成（P<0.05）,并且浓度为5%与10%的RUT 软膏能显著降低小鼠背部CGRP 含量（P<0. 05）,但是其对小鼠血浆的CGRP 没有影响。结论：吴茱萸次碱外用对小鼠银屑病模型有一定的治疗作用,这种作用与其促进小鼠 皮肤CGRP 释放而导致其含量降低有关。     

Polyunsaturated fatty acid metabolites as novel lipidomic biomarkers for noninvasive diagnosis of nonalcoholic steatohepatitis

Lipotoxicity is a key mechanism thought to be responsible for the progression of nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH). Noninvasive diagnosis of NASH is a major unmet clinical need, and we hypothesized that PUFA metabolites, in particular arachidonic acid (AA)-derived eicosanoids, in plasma would differentiate patients with NAFL from those with NASH. Therefore, we aimed to assess the differences in the plasma eicosanoid lipidomic profile between patients with biopsy-proven NAFL versus NASH versus normal controls without nonalcoholic fatty liver disease (NAFLD; based on MRI fat fraction <5%). We carried out a cross-sectional analysis of a prospective nested case-control study including 10 patients with biopsy-proven NAFL, 9 patients with biopsy-proven NASH, and 10 non-NAFLD MRI-phenotyped normal controls. We quantitatively compared plasma eicosanoid and other PUFA metabolite levels between NAFL versus NASH versus normal controls. Utilizing a uniquely well-characterized cohort, we demonstrated that plasma eicosanoid and other PUFA metabolite profiling can differentiate between NAFL and NASH. The top candidate as a single biomarker for differentiating NAFL from NASH was 11,12-dihydroxy-eicosatrienoic acid (11,12-diHETrE) with an area under the receiver operating characteristic curve (AUROC) of 1. In addition, we also found a panel including 13,14-dihydro-15-keto prostaglandin D₂ (dhk PGD2) and 20-carboxy arachidonic acid (20-COOH AA) that demonstrated an AUROC of 1. This proof-of-concept study provides early evidence that 11,12-diHETrE, dhk PGD2, and 20-COOH AA are the leading eicosanoid candidate biomarkers for the noninvasive diagnosis of NASH.     

马铃薯杂种无性株系的SSR鉴定及花粉育性和染色体构型分析

为明确马铃薯‘MB09’ב陇薯7号’杂种F1无性株系在DNA和细胞遗传学水平上的差异,该试验以亲本材料为对照,利用SSR分子标记技术对其20个优良无性株系(F1无性系一代)的DNA指纹特征进行分析,并采用常规制片镜检方法对已选出的8个杂种优良株系(F1无性系二代)的花粉育性及花粉母细胞减数分裂中期Ⅰ(PMCMⅠ)的染色体配对构型进行了研究,为马铃薯杂交新品系选育提供分子细胞遗传学依据。结果显示:(1)试验共筛选出2对SSR特异引物C57和S25,通过PCR扩增建立了能识别出这20个杂种株系及其双亲的SSR指纹图。(2)杂种优异株系F1-1、F1-2、F1-7、F1-11、F1-13、F1-14、F1-15和F1-20的花粉可育率变幅为36.73%~87.08%,并以株系F1-7最高(87.08%),而且显著超过高亲(83.33%),说明各优良株系花粉育性有一定差异。(3)对8个优异株系花粉母细胞的PMCMⅠ观察发现,各优良株系的染色体配对构型明显不同,均包括单价体、二价体、三价体和四价体4类,其中二价体构型的比例最高,其介于49.13%~82.91%之间,其中以株系F1-7的二价体比例最高(82.91%)。该研究明确了20个马铃薯杂种优良株系的SSR指纹特征和8个优异株系的花粉育性及染色体配对构型差异。