煤绒菌原质团和菌核甲醇提取物抗氧化活性的研究

为探索黏菌的抗氧化活性,以总还原力、DPPH自由基清除率及O2自由基清除率为指标,首次对煤绒菌原质团和菌核甲醇提取物进行抗氧化活性研究。结果表明:煤绒菌原质团和菌核甲醇提取物均有较好的抗氧化活性,当质量浓度为0.8 mg/mL时,二者对O2自由基的清除能力最强,清除率分别为70.39%和86.83%;当质量浓度为0.4 mg/mL时,二者对DPPH自由基的清除能力最强,清除率分别为57.22%和62.91%,通过比较IC50值,菌核粗提物的抗氧化能力略优于原质团。     

林檎叶水提物及其不同极性组分的抑菌和清除自由基作用的研究

采用管碟法及体外抗氧化活性测试方法,以抑菌圈大小及对DPPH的半清除率浓度(IC50)为指标,评价林檎叶水提物及其不同极性组分(包括乙酸乙醑、正丁醇萃取物、及乙醇沉淀物和剩余组分)的抑菌及清除DP-PH自由基的能力.结果显示林檎叶乙酸乙酯组分对大肠杆菌、枯草杆菌、金黄色葡萄球菌、黑曲霉、毛霉、红酵母及啤酒酵母均有抑制作用;且对DPPH自由基的清除能力最强,且清除率和质量浓度之间存在剂量依赖的关系,IC50值为0.33 mg/mL.有望成为新型的天然防腐保鲜剂的原料.     

恒山黄芪和宁夏枸杞的多糖体外抗氧化活性比较研究

以恒山黄芪和宁夏枸杞为材料,采用超声波法提取其多糖成分,比较分析恒山黄芪多糖、宁夏枸杞多糖以及二者复合多糖的抗氧化活性,为开发新的天然抗氧化剂提供依据。结果显示:(1)恒山黄芪多糖的总抗氧化能力[T-AOC=(0.67±0.12)U/mg]和超氧阴离子自由基清除能力(EC50=2.34 mg/mL)均高于宁夏枸杞多糖[TAOC=(0.52±0.07)U/mg,EC50=4.28mg/mL],而恒山黄芪多糖的羟自由基清除能力(EC50=1.36mg/mL)则低于宁夏枸杞多糖(EC50=0.98mg/mL)。(2)在相同浓度下,二者按照1∶1比例配成的复合多糖总抗氧化能力[T-AOC=(0.79±0.02)U/mg]、羟自由基清除能力(EC50=0.84mg/mL)、超氧阴离子自由基清除能力(EC50=1.37mg/mL)均高于单种多糖。(3)恒山黄芪多糖、宁夏枸杞多糖以及二者复合多糖的抗氧化能力均与其浓度呈正相关关系。研究表明,恒山黄芪多糖具有较好的抗氧化活性,是具有开发潜力的天然抗氧化物质,且恒山黄芪多糖与宁夏枸杞多糖复合配伍后具有协同效应,抗氧化活性增强。为开发新的天然抗氧化剂提供参考。     

赶黄草总黄酮分级萃取及活性分析

以赶黄草茎叶为实验材料,用乙酸乙酯、正丁醇对赶黄草乙醇粗提物(EF)进行分级萃取,依次得到乙酸乙酯相(AF)、正丁醇相(BF)和水相(WF),分别测定各相黄酮含量、体外抗氧化和抑菌活性。结果表明,乙酸乙酯相的黄酮含量最高,为133.36 mg/g,超过赶黄草总黄酮含量的50%;乙酸乙酯相的DPPH自由基、羟自由基、超氧阴离子清除能力和亚铁离子螯合能力最强,其IC_(50)值分别为0.076、0.209、0.038、0.593 mg/mL;乙酸乙酯相的抑菌效果显著,对金黄色葡萄球菌和铜绿假单胞菌的最低抑菌浓度均为0.075 mg/mL。     

蛹虫草无性型菌丝体提取液体外抗氧化活性研究

分别测定了蛹虫草无性型菌丝体不同溶剂提取液在不同抗氧化模型中的抗氧化作用。结果表明,各种提取液对二苯基苦味酰基苯肼自由基(·DPPH)和羟自由基(·OH)均有显著的清除作用:在50mg/mL时,去离子水、70%乙醇和70%丙酮提取物对DPPH自由基的清除率分别为89.2%、83.6%和75.9%;70%乙醇提取物在30mg/mL时对·OH自由基的清除率达到100%;在50mg/mL时70%丙酮和去离子水提取物的·OH自由基清除率分别为95.6%和89.6%。在一定浓度下,各提取液对邻苯三酚自氧化也均有抑制作用;不同溶剂提取物的还原能力强弱为:70%乙醇>去离子水>70%丙酮。各种提取物的抗氧化组分不同,提取物浓度与抗氧化性成正相关。     

三种木层孔菌子实体不同溶剂提取物抗氧化活性的研究

以抗坏血酸为阳性对照,分别对桑木层孔菌Phellinus mori、鲍姆木层孔菌Phellinus baumii和瓦宁木层孔菌Phellinus vaninii野生子实体甲醇提取物(ME)、氯仿提取物(CE)、乙酸乙酯提取物(EAE)、正丁醇提取物(BE)和热水提取物(WE)的体外清除DPPH(1,1-二苯基-2-三硝基苯肼)自由基、羟自由基和总抗氧化能力进行了检测。结果表明,3种木层孔菌的不同溶剂提取物都具有体外抗氧化活性。3种菌EAE清除DPPH自由基能力较强,其中瓦宁木层孔菌EAE清除DPPH自由基能力最强,IC50为10.65μg/mL。3种木层孔菌热水浸提物清除羟自由基的能力较强,鲍姆木层孔菌WE的清除率最高,1mg/mL时达到73.52%。另外,3种木层孔菌不同提取物总抗氧化能力和清除DPPH自由基能力基本相同,瓦宁木层孔菌BE的总抗氧化能力最强,1mg/mL时达到了167.7U/mL。3种木层孔菌相比,瓦宁木层孔菌不同提取物的体外抗氧化能力最强,其次是鲍姆木层孔菌,桑木层孔菌的体外抗氧化能力最弱。     

鸭舌草中抗氧化活性物质的分离与鉴定

采用溶剂萃取法将鸭舌草75%乙醇提取物浸膏分成4个不同组分,并用碘量法测定其抗氧化活性.结果表明,高极性组分正丁醇相具有最强的抗氧化活性,与天然抗氧化剂茶多酚和化学合成抗氧化剂BHT的抗氧化活性相当,显著高于对照.利用柱层析技术对具有高抗氧化活性组分正丁醇相进一步分离纯化,并确定为豆甾醇葡萄糖甙.以BHT为对照对羟自由基进行清除试验,结果表明,与对照抗氧化剂BHT相比,它们对羟自由基具有更高的清除率.     

旱莲草多糖的提取及其抗氧化活性研究

采用水/甲醇混合溶剂浸泡提取旱莲草的多糖组分,利用硅胶柱层析和中压液相色谱,对多糖进行分离纯化,纯化后的多糖组分经薄层层析分析发现,这些多糖主要组成单糖均为葡萄糖和果糖。旱莲草多糖在总还原能力、总抗氧化能力和FRAP抗氧化能力测试中均显示较好的活性,能够有效清除羟自由基和DPPH自由基,在1.5 mg/m L的浓度下,对羟自由基的清除效率为(12.33~56.81)%,粗多糖组分在1 mg/m L的浓度下对DPPH自由基的清除效率为(17.88~84.47)%,精分多糖组分在5 mg/m L的浓度下,对DPPH自由基的清除效率为(18.64~91.35)%;极性小的多糖抗氧化活性显著优于极性大的多糖,抗氧化活性最高可达后者的11倍之多;粗多糖组分的抗氧化活性一般优于纯化后的相应精多糖组分,这说明旱莲草的不同多糖分子之间可能存在协同抗氧化作用。     

响应面法优化豫西山茱萸叶黄酮的提取及其抑菌和抗氧化活性

通过响应面法对山茱萸叶黄酮的提取工艺进行优化,并对其体外抑菌和抗氧化活性进行研究。经优化后,山茱萸叶黄酮在超声功率290 W、液料比31∶1(mL/g)、乙醇体积分数61%、提取时间23 min的工艺条件下提取得率最高,达到6.31%,与模型预测值相符。抑菌实验结果表明山茱萸叶黄酮对沙门氏菌有较强的抑菌作用,对绿脓杆菌、金黄色葡萄球菌和中华根霉有较弱的抑菌作用,说明山茱萸叶黄酮对细菌有较强的抑菌作用,对真菌有较弱的抑菌作用。山茱萸叶黄酮浓度为1.2 mg/mL时其对DPPH自由基的清除率为77.24%,对羟基自由基的清除率达到83.54%;山茱萸叶黄酮清除DPPH自由基和羟基自由基的IC_(50)分别为0.699和0.631 mg/L,表明山茱萸叶黄酮具有较强的抗氧化活性。     

柠条锦鸡儿不同极性部位抗氧化及抗须癣毛癣菌活性初筛

本文对柠条锦鸡儿的花、叶、枝皮和根皮的乙醇提取物进行了极性部位的分离,并对各部位的提取物进行了抗氧化及抗须癣毛癣菌的活性筛选。抗氧化活性通过DPPH、ABTS、羟自由基(·OH)和超氧阴离子(O_2~-·)自由基的清除能力来评价,抗须癣毛癣菌活性通过抑菌圈实验来进行初步筛选。结果表明,以Vc为对照,柠条锦鸡儿花和叶的提取物具有很好的DPPH和ABTS自由基的清除能力,尤其是它们的乙酸乙酯部位;但所有的提取物对·OH和O_2~-·自由基的清除能力均较弱(P0.001)。抑菌圈实验发现,花、叶和枝皮的乙酸乙酯部位具有一定的抗菌活性,其中枝皮的抗菌活性最好;通过测定生物量,当秋季采集枝皮乙酸乙酯部位提取物浓度为128μg/m L其抑菌率可达到50%。活性筛选结果说明柠条锦鸡儿的花、叶和枝皮具有一定的深入开发潜力。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.