99mTc标记BmK CT及其胶质瘤荷瘤裸鼠的SPECT成像研究

目的:通过放射性核素~(99m)Tc标记BmK CT多肽制备靶向胶质瘤的显像剂,探讨~(99m)?Tc-BmK CT用于胶质瘤显像的可行性。方法:采用BmK CT多肽游离的氨基与DTPA酸酐反应得到BmK CT-DTPA,经99m Tc标记后通过柱层析分离纯化制备~(99m)?Tc-BmK CT。测定标记物在PBS溶液和血清中不同时间点放射性化学纯度,评价BmK CT-~(99m)?Tc体外稳定性。新西兰白兔耳缘静脉注射~(99m)Tc-BmK CT进行SPECT显像,观察不同时间点体内的放射性分布。皮下胶质瘤裸鼠经尾静脉注射~(99m)Tc-BmK CT,观察不同时间点肿瘤的摄取情况;注射后4 h处死裸鼠,分离肿瘤和主要器官进行离体SPECT显像,并用勾画感兴趣区法分析相对放射性计数。结果:~(99m)Tc标记BmK CT多肽标记率大于80%,经柱层析分离纯化后放射性化学纯度大于99%。标记物在PBS和血清稳定性良好,6 h内放射性化学纯度均大于95%,12 h内放射性化学纯度大于90%。正常白兔SPECT显像表明~(99m)Tc-BmK CT主要浓聚在肝脏、脾脏和肾脏,软组织持续显影微弱,甲状腺区及胃肠未见核素浓聚;显像剂主要通过泌尿系统排泄,24 h肾脏与肝脏显影接近。胶质瘤裸鼠SPECT显像表明,注射后4 h肿瘤显像清楚,ROI分析结果显示肿瘤/肌肉比4.26±0.25,标记物在肿瘤内代谢缓慢,8 h肿瘤部位仍有较高摄取。结论:本研究成功制备了~(99m)Tc标记BmK CT多肽,标记物主要被肝、脾和肾摄取,经泌尿系统排泄;~(99m)Tc-BmK CT能够在皮下胶质瘤中浓聚,注射后4 h肿瘤显影清晰,瘤内代谢缓慢,有潜力成为一种新型胶质瘤分子探针。     

Mitochondrial Calcium uniporters are essential for meiotic progression in mouse oocytes by controlling Ca2+ entry

ObjectivesThe alteration of bioenergetics by oocytes in response to the demands of various biological processes plays a critical role in maintaining normal cellular physiology. However, little is known about the association between energy sensing and energy production with energy‐dependent cellular processes like meiosis.Materials and methodsWe demonstrated that cell cycle‐dependent mitochondrial Ca²⁺ connects energy sensing to mitochondrial activity in meiosis progression within mouse oocytes. Further, we established a model in mouse oocytes using siRNA knockdowns that target mitochondrial calcium uniporters (MCUs) in order to inhibit mitochondrial Ca²⁺ concentrations.ResultsDecreased numbers of oocytes successfully progressed to the germinal vesicle stage and extruded the first polar body during in vitro culture after inhibition, while spindle checkpoint‐dependent meiosis was also delayed. Mitochondrial Ca²⁺ levels changed, and this was followed by altered mitochondrial masses and ATP levels within oocytes during the entirety of meiosis progression. Abnormal mitochondrial Ca²⁺ concentrations in oocytes then hindered meiotic progress and activated AMP‐activated protein kinase (AMPK) signalling that is associated with gene expression.ConclusionsThese data provide new insight into the protective role that MCU‐dependent mitochondrial Ca²⁺ signalling plays in meiotic progress, in addition to demonstrating a new mechanism of mitochondrial energy regulation by AMPK signalling that influences meiotic maturation.     

Efficient Synthesis of 8-Thiosubstituted Guanine Derivatives as Potential Tools for Biochemical and Biological Studies

Abstract

A method for the selective introduction of the N²-(dimethylamino)methylene group into 8-thio-9-(2-hydroxyethoxymethyl)guanine (1) has been developed. The effect of the N²-amidine protection on the S-alkylation of 1 was studied.     

Irgm 1参与动脉粥样硬化斑块的形成

目的:探讨免疫相关GTP酶1(Irgm 1)对小鼠血管动脉粥样硬化(AS)斑块形成的影响。方法:高脂饲料喂养野生型(WT)、ApoE~(-/-)Irgm 1~(+/+)和ApoE~(-/-)Irgm1~(+/-)小鼠3个月,建立AS模型;取小鼠主动脉弓,免疫荧光染色方法观察WT和ApoE~(-/-)Irgm 1~(+/+)小鼠血管AS斑块中Irgm 1的表达情况及部位;Western blot方法检测WT和ApoE~(-/-)Irgm 1~(+/+)小鼠血管AS斑块中Irgm 1蛋白表达情况;Q-PCR方法检测WT和ApoE~(-/-)Irgm 1~(+/+)小鼠血管AS斑块中Irgm 1 m RNA表达情况;油红O染色观察ApoE~(-/-)Irgm1~(+/+)和ApoE~(-/-)Irgm1~(+/-)小鼠血管AS斑块形成情况;结果:与WT组相比,ApoE~(-/-)Irgm 1~(+/+)组小鼠主动脉弓AS斑块中Irgm 1+细胞明显增多,Irgm 1+细胞主要位于血管AS斑块的表面;与WT组相比,ApoE~(-/-)Irgm 1~(+/+)组小鼠血管AS斑块中Irgm 1蛋白表达显著增多(P0.001),Irgm 1 m RNA表达显著增多(P0.01);与ApoE~(-/-)Irgm1~(+/-)组相比,ApoE~(-/-)Irgm1~(+/+)组小鼠主动脉弓AS斑块面积显著增大(P0.01);结论:Irgm 1能够促进血管AS斑块的形成。     

Species-specific expression of sialosyl-Lex on polymorphonuclear leukocytes (PMN), in relation to selectin-dependent PMN responses

Sialosyl-Le^x (SLe^x) and its positional isomer sialosyl-Le^a are the epitopes recognized by the lectin domain of E- and P-selectins. Expression of SLe^x in polymorphonuclear leukocytes (PMN) plays an important role in recruitment of these cells at sites of inflammation through activation of selectins. We studied expression of SLe^x in PMN of seven mammalian species in comparison with that in humans. Only PMN of humans (no other species) expressed SLe^x or other lacto-series epitopes such as Le^x or Le^y. The observed absence of these epitopes in rat PMN seems inconsistent with recent reports that the lung inflammation process in a rat model is inhibited by perfusion of SLe^x oligosaccharide (Mulligan MS,et al. (1993a)Nature 364:149; (1993b)J Exp Med 178:623). Rat selectins may be able to recognize SLe^x, even though this epitope is absent in rat PMN.Abbreviations FITC fluorescein isothiocyanate - mAb monoclonal antibody - PMN polymorphonuclear leukocytes - SLe^a sialosyl-Le^a antigen - SLe^x sialosyl-Le^x antigen     

基于双层BiGRU网络的哺乳动物组织m6A甲基化位点预测

目的 N⁶-甲基化腺苷（N⁶-methyladenosine，m⁶A）是RNA中最常见、最丰富的化学修饰，在很多生物过程中发挥着重要作用。目前已经发展了一些预测m⁶A甲基化位点的计算方法。然而，这些方法在针对不同物种或不同组织时，缺乏稳健性。为了提升对不同组织中m⁶A甲基化位点预测的稳健性，本文提出一种能结合序列反向信息来提取数据更高级特征的双层双向门控循环单元（bidirectional gated recurrent unit，BiGRU）网络模型。方法 本文选取具有代表性的哺乳动物组织m⁶A甲基化位点数据集作为训练数据，通过对模型网络、网络结构、层数和优化器等进行搭配，构建双层BiGRU网络。结果 将模型应用于人类、小鼠和大鼠共11个组织的m⁶A甲基化位点预测上，并与其他方法在这11个组织上的预测能力进行了全面的比较。结果表明，本文构建的模型平均预测接受者操作特征曲线下面积（area under the receiver operating characteristic curve，AUC）达到93.72%，与目前最好的预测方法持平，而预测准确率（accuracy，ACC）、敏感性（sensitivity，SN）、特异性（specificity，SP）和马修斯相关系数（Matthews correlation coefficient，MCC）分别为90.07%、90.30%、89.84%和80.17%，均高于目前的m⁶A甲基化位点预测方法。结论 和已有研究方法相比，本文方法对11个哺乳动物组织的m⁶A甲基化位点的预测准确性均达到最高，说明本文方法具有较好的泛化能力。     

Chalcones isolated from Angelica keiskei inhibit cysteine proteases of SARS-CoV

Two viral proteases of severe acute respiratory syndrome coronavirus (SARS-CoV), a chymotrypsin-like protease (3CL^pro) and a papain-like protease (PL^pro) are attractive targets for the development of anti-SARS drugs. In this study, nine alkylated chalcones (1–9) and four coumarins (10–13) were isolated from Angelica keiskei, and the inhibitory activities of these constituents against SARS-CoV proteases (3CL^pro and PL^pro) were determined (cell-free/based). Of the isolated alkylated chalcones, chalcone 6, containing the perhydroxyl group, exhibited the most potent 3CL^pro and PL^pro inhibitory activity with IC₅₀ values of 11.4 and 1.2?µM. Our detailed protein-inhibitor mechanistic analysis of these species indicated that the chalcones exhibited competitive inhibition characteristics to the SARS-CoV 3CL^pro, whereas noncompetitive inhibition was observed with the SARS-CoV PL^pro.     

A new heterobinuclear FeIIICuII complex with a single terminal FeIII–O(phenolate) bond. Relevance to purple acid phosphatases and nucleases

A novel heterobinuclear mixed valence complex [Fe^IIICu^II(BPBPMP)(OAc)₂]ClO₄, 1, with the unsymmetrical N₅O₂ donor ligand 2-bis[{(2-pyridylmethyl)aminomethyl}-6-{(2-hydroxybenzyl)(2-pyridylmethyl)}aminomethyl]-4-methylphenol (H₂BPBPMP) has been synthesized and characterized. A combination of data from mass spectrometry, potentiometric titrations, X-ray absorption and electron paramagnetic resonance spectroscopy, as well as kinetics measurements indicates that in ethanol/water solutions an [Fe^III–()OH–Cu^IIOH₂]⁺ species is generated which is the likely catalyst for 2,4-bis(dinitrophenyl)phosphate and DNA hydrolysis. Insofar as the data are consistent with the presence of an Fe^III-bound hydroxide acting as a nucleophile during catalysis, 1 presents a suitable mimic for the hydrolytic enzyme purple acid phosphatase. Notably, 1 is significantly more reactive than its isostructural homologues with different metal composition (Fe^IIIM^II, where M^II is Zn^II, Mn^II, Ni^II, or Fe^II). Of particular interest is the observation that cleavage of double-stranded plasmid DNA occurs even at very low concentrations of 1 (2.5 M), under physiological conditions (optimum pH of 7.0), with a rate enhancement of 2.7×10⁷ over the uncatalyzed reaction. Thus, 1 is one of the most effective model complexes to date, mimicking the function of nucleases.Electronic Supplementary Material Supplementary material is available for this article at .     

血清IL-6、IL-8、IgM抗体及T细胞亚群水平对新生儿先天性梅毒的诊断价值

目的:探讨血清白介素-6(IL-6)、白介素-8(IL-8)、IgM抗体及T细胞亚群对先天性梅毒新生儿的诊断价值。方法:选择2015年5月至2017年5月在我院进行临床治疗的先天性梅毒新生儿81例为观察组,另选同期来我院进行健康体检81例新生儿为对照组。比较两组患者血清IL-6、IL-8、T细胞亚群中CD~(3+)、CD~(4+)、CD~(8+)、CD~(4+)/CD~(8+)细胞及IgM抗体的阳性率。结果:治疗后,观察组血清IL-6、IL-8水平均明显高于对照组(P0.05),T细胞亚群中CD~(3+)、CD~(4+)、CD~(4+)/CD~(8+)明显低于对照组,而CD~(8+)T细胞比例高于对照组(P0.05)。19S-IgM-TP ELISA法检测出IgM的阳性率92.59%,明显高于TRUST法(74.07%)及TP-ELSA法(70.37%)(P0.05)。ROC曲线中,血清IL-8特异度为88.34%明显高于血清IL-6特异度81.48%、IgM抗体特异度60.13%、T细胞亚群特异度65.34%;IgM抗体的曲线面积88.91 cm~2明显大于IL-6的曲线面积45.09 cm~2、IL-8的曲线面积76.19 cm~2、T细胞亚群的曲线面积77.35 cm~2;T细胞亚群准备性67.89%明显高于IL-6准确性60.39%、IL-8准确性51.09%、IgM抗体准确性50.12;IgM抗体的灵敏度60.13%高于IL-6灵敏度59.19%、IL-8灵敏度42.35%、T细胞亚群灵敏度59.37%。具有比较意义(P0.05)。结论:血清IL-6、IL-8水平、T细胞亚群中CD~(3+)、CD~(4+)、CD~(8+)、CD~(4+)/CD~(8+)及IgM抗体阳性率是诊断先天性梅毒新生儿的重要指标。     

反硝化除磷戈登氏菌属的富集及其菌剂制备

【背景】投加微生物菌剂是强化生物处理效能的重要手段,反硝化是污水脱氮除磷的关键步骤,但目前对于反硝化微生物菌剂相关的研究报道较少。【目的】驯化高效反硝化聚磷菌菌剂,并对系统进行生物强化。【方法】采用两阶段法快速富集反硝化聚磷菌,筛选高效脱氮除磷功能菌株NC1-1并进行鉴定,以NC1-1为菌种来源制备干粉菌剂,研究菌剂强化A²SBR系统污水处理效果。【结果】历经36 d后反硝化聚磷菌富集成功,菌株NC1-1经鉴定属于戈登氏菌属,其脱氮除磷率分别为89.46%和91.68%。麦麸、玉米粉配比为85%:15%、NC1-1投菌量为20 mL、发酵液用量20 mL的条件下成功制得干粉菌剂,干粉菌剂最佳投加量为10%的A²SBR系统总磷（total phosphorus,TP）和NO₃^--N去除率比未投加菌剂的A²SBR系统提高12.06%和11.52%。【结论】菌剂NC1-1的投加使A²SBR系统的污染物去除效能进一步提高,研究结果为进一步研究反硝化聚磷菌菌剂提供了...     

NMR Spectroscopic Study of a DNA Duplex with Mercury-Mediated T-T Base Pairs

Recently, we reported that T-T mismatches can specifically recognize Hg ^II (T-Hg ^II -T pair formation). In order to understand the properties of the T-Hg ^II -T pair, we recorded NMR spectra for a DNA duplex, d(CGCG TT GTCC) ? d(GGAC TT CGCG), with two successive T-T mismatches (Hg ^II -binding sites). We assigned ¹ H resonances for mercury-free and di-mercurated duplexes, and performed titration experiments with Hg ^II by using 1D ¹ H NMR spectra. Because of the above mentioned assignments, we could confirm the existence of mono-mercurated species, because individual components gave independent NMR signals in the titration spectra.     

Partial mycoheterotrophy is common among chlorophyllous plants with Paris-type arbuscular mycorrhiza

Background and AimsAn arbuscular mycorrhiza is a mutualistic symbiosis with plants as carbon providers for fungi. However, achlorophyllous arbuscular mycorrhizal species are known to obtain carbon from fungi, i.e. they are mycoheterotrophic. These species all have the Paris type of arbuscular mycorrhiza. Recently, two chlorophyllous Paris-type species proved to be partially mycoheterotrophic. In this study, we explore the frequency of this condition and its association with Paris-type arbuscular mycorrhiza.MethodsWe searched for evidence of mycoheterotrophy in all currently published ¹³C, ²H and ¹⁵N stable isotope abundance patterns suited for calculations of enrichment factors, i.e. isotopic differences between neighbouring Paris- and Arum-type species. We found suitable data for 135 plant species classified into the two arbuscular mycorrhizal morphotypes.Key ResultsAbout half of the chlorophyllous Paris-type species tested were significantly enriched in ¹³C and often also enriched in ²H and ¹⁵N, compared with co-occurring Arum-type species. Based on a two-source linear mixing model, the carbon gain from the fungal source ranged between 7 and 93 % with ferns > horsetails > seed plants. The seed plants represented 13 families, many without a previous record of mycoheterotrophy. The ¹³C-enriched chlorophyllous Paris-type species were exclusively herbaceous perennials, with a majority of them thriving on shady forest ground.ConclusionsSignificant carbon acquisition from fungi appears quite common and widespread among Paris-type species, this arbuscular mycorrhizal morphotype probably being a pre-condition for developing varying degrees of mycoheterotrophy.     

Conformationally Restricted 2-Substituted Wyosine Derivatives. 1H, 13C,and 15N NMR Study

Abstract

It was found by ¹H, ¹³C and ¹⁵N NMR study that substitution of 4,9-dihydro-4, 6-dimethyl-9-oxo-3-(2′,3′,5′-tri-O-acetyl-β-D-ribofuranosyl) imidazo [1,2-a]purine (wyosine triacetate, 1) at C2 position with electronegative groups CH₃O and C₆H₅CH₂O results in a noticeable electron distribution disturbance in the “left-hand” imidazole ring and a significant increase in the North conformer population of the sugar moiety.     

Patterns of soil and plant nitrogen isotope composition and their relationships with climate factors in Xilingol League,Inner Mongolia,China

Background: Plant and soil nitrogen stable isotope (δ¹⁵N) can integrate several fundamental biogeochemical processes in ecosystem nitrogen dynamics, and reflect characteristics of ecosystem nitrogen cycling.

Aims: We investigated how climate change influenced plant-soil nitrogen cycling by relating soil δ¹⁵N, plant δ¹⁵N and Δδ¹⁵N (difference between soil and plant δ¹⁵N) with climatic factors.

Methods: Field investigation was conducted in temperate grasslands in Inner Mongolia during August 2015. Plant δ¹⁵N, soil δ¹⁵N and Δδ¹⁵N were determined, and their relationships with climatic factors were examined by simple regression analyses and general linear models.

Results: Soil δ¹⁵N was significantly higher than plant δ¹⁵N, and there was a positive linear correlation between them. Soil and plant δ¹⁵N were negatively related with mean annual precipitation (MAP) and positively with mean annual temperature (MAT); conversely, Δδ¹⁵N was positively related with MAP and negatively with MAT.

Conclusion: Soil δ¹⁵N was dominantly controlled by MAT, while it was MAP for plant δ¹⁵N. Climate factors influenced plant δ¹⁵N not only through their effects on soil nitrogen dynamics but also strategies of plant nitrogen acquisition. Thus, compared with plant δ¹⁵N, soil δ¹⁵N can more accurately reflect soil nitrogen dynamics, while plant δ¹⁵N may integrate soil nitrogen dynamics and plant nitrogen acquisition.     

低H~+_-ATPase活性植物乳杆菌突变菌筛选及基因表达的相对定量分析

【目的】筛选H~+_-ATPase活性降低的植物乳杆菌突变菌,比较其与亲本菌基因表达水平的差异,进一步探索H~+_-ATPase的调控机制。【方法】利用硫酸新霉素诱变、筛选突变菌,并对亲本菌(ZUST)和突变菌(ZUST-1、ZUST-2)进行生长、产酸能力及H~+_-ATPase活性的测定。分别提取亲本菌和突变菌的基因组DNA,扩增H~+_-ATPase全部编码基因并测序。通过荧光定量PCR对H~+_-ATPase全部编码基因进行相对定量分析。【结果】突变菌的生长和产酸能力均低于亲本菌,突变菌ZUST-1和ZUST-2的H~+_-ATPase活性比亲本菌分别降低了10.1%和28.8%。突变菌ZUST-1和ZUST-2的atp A基因均有22个位点发生突变,而ZUST-2的atp C基因有6个位点发生突变。突变菌ZUST-1和ZUST-2的atp A在对数期基因表达水平分别比亲本菌ZUST下调了41.1%和35.7%,在稳定期分别下调了43.6%和14.2%;ZUST-1的atp C基因在对数期的表达水平比ZUST略高,在稳定期比ZUST上调了30%,而ZUST-2的atp C基因未表达。【结论】突变菌H~+_-ATPase活性减弱会导致其全部编码基因在稳定期表达水平上调(除ZUST-2的atp C不表达外),而且atp A和atp C基因突变导致的基因表达水平的差异是影响H~+_-ATPase活性的主要因素,此研究结果为进一步研究植物乳杆菌中H~+_-ATPase的调控机制奠定了基础。     

New Reagent for Protein-DNA Contacts Footprinting

Abstract

We have found, that the reaction of o-bromobenzoic acid with Cu²⁺ ions can be used as a source of activated oxygen species capable of cleaving DNA. Possibility to apply this reaction for footprinting the nucleosome core in the reconstituted chromatin was demonstrated.     

Structures and stability of N<Subscript>13</Subscript><Superscript>+</Superscript> and N<Subscript>13</Subscript><Superscript>−</Superscript> clusters

The structures and stabilities of eleven N₁₃ ⁺ and N₁₃ ^– isomers have been investigated with second-order Møller–Plesset (MP2) and density functional theory (DFT) methods. Five N₁₃ ⁺ isomers and six N₁₃ ^– isomers are all reasonable local minima on their potential energy hypersurfaces. The most stable N₁₃ ⁺ cation is structure C-2 with C_2v symmetry, which contains a pentazole ring and two N₄ open chains. It is different from those of the N₇ ⁺ and N₉ ⁺ clusters, but similar to the N₁₁ ⁺ cluster. Meanwhile, the most stable N₁₃ ^– structure A-2 is composed of a pentazole ring and a six-membered ring connected by two nitrogen atoms. It is not only different from those of the N₇ ^– and N₉ ^– clusters, but also from the N₁₁ ^– cluster. The decomposition pathways of structures C-2 and A-2 were investigated at the B3LYP/(aug)-cc-pVDZ level. From the barrier heights of the structures C-2 and A-2 decomposition processes, it is suggested that C-2 is difficult to observe experimentally and A-2 may be observed as a short-lived species. Figure Optimized geometrical parameters of N₁₃ ⁺ isomer C-2      

Using matrix summation method for three dimensional dose calculation in brachytherapy

AimThe purpose of this study is to calculate radiation dose around a brachytherapy source in a water phantom for different seed locations or rotation the sources by the matrix summation method.BackgroundMonte Carlo based codes like MCNP are widely used for performing radiation transport calculations and dose evaluation in brachytherapy. But for complicated situations, like using more than one source, moving or rotating the source, the routine Monte Carlo method for dose calculation needs a long time running.Materials and methodsThe MCNPX code has been used to calculate radiation dose around a ¹⁹²Ir brachytherapy source and saved in a 3D matrix. Then, we used this matrix to evaluate the absorbed dose in any point due to some sources or a source which shifted or rotated in some places by the matrix summation method.ResultsThree dimensional (3D) dose results and isodose curves were presented for ¹⁹²Ir source in a water cube phantom shifted for 10 steps and rotated for 45 and 90° based on the matrix summation method. Also, we applied this method for some arrays of sources.ConclusionThe matrix summation method can be used for 3D dose calculations for any brachytherapy source which has moved or rotated. This simple method is very fast compared to routine Monte Carlo based methods. In addition, it can be applied for dose optimization study.     

Cr3+和Cd2+对普通小球藻生长及抗氧化酶活性的影响

[目的] 为探究重金属对淡水绿藻生长的影响。[方法] 选取对水质检测具有明显指示作用的普通小球藻（Chlorella vulgaris）为实验材料,CdCl₂·2H₂O和CrCl₃·7H₂O提供重金属离子,探究不同浓度Cr³⁺和Cd²⁺在单一和复合胁迫下对藻细胞浓度、叶绿素a及相关抗氧化酶活性的影响。[结果] 随着Cr³⁺和Cd²⁺浓度不断增加,藻细胞浓度呈先增长后下降趋势;叶绿素a含量呈现先下降后升高再下降的现象,浓度为1 mg/L的单一和复合胁迫下有最大值,且毒性作用表现为Cr³⁺ < Cd²⁺ < Cr³⁺+Cd²⁺;与藻细胞膜相关的丙二醛（MDA）和过氧化氢（H₂O₂）含量随着重金属离子浓度的增大而增长;重金属离子浓度低于10 mg/L时对藻细胞内抗氧化酶系统中的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）表现为促进作用,而大于10 mg/L时具有抑制作用。[结论] 结果表明在单一或复合重金属胁迫下,普通小球藻会充分调动与抗逆性相关的酶来维持自身的正常生长。