红平菇产漆酶条件优化及对孔雀绿染料脱色的研究

采用LNAS(低氮天冬酰胺-琥珀酸)培养基添加方式,对红平菇Pleurotus djamor HP1进行培养,检测不同时间培养液对不同底物的氧化作用,进而得到光密度值的变化情况,作为漆酶的产生及活性测定的主要依据。结果表明:在含Cu2+的培养液中漆酶最大酶活为235.4 U/L。含Cu2+的培养液添加底物木屑后漆酶最大酶活为458.8 U/L。提取经优化筛选后的培养基培养出的漆酶粗酶液,对4种具有不同化学结构的染料进行了脱色试验。结果表明:三苯基甲烷类的孔雀绿在6 h时脱色率为87.5%,蒽醌类的SN4R在24 h时脱色率为49.4%,偶氮类的甲基橙在24 h时脱色率为45%,杂环类的中性红在24 h时脱色率为23.6%。因此,显示出红平菇漆酶对孔雀绿染料脱色具有较大的应用潜力,进而对废水处理具有更好的应用前景。     

Ganoderma lucidum U-281漆酶催化偶氮染料活性黑5脱色

漆酶在纺织染料脱色及印染废水处理领域有着广阔的应用前景。活性黑5是纺织印染中应用广泛的偶氮类活性染料,结构复杂,生物降解性低。以灵芝菌Ganoderma lucidum U-281所产漆酶对活性黑5进行氧化脱色,采用单因素逐一优化方法得到了U-281漆酶催化活性黑5脱色的工艺参数：染料初始浓度25mg/L、漆酶用量2.0U/mL、铜离子添加量40mmol/L、pH 6.0、40℃。在优化条件下,4h可使RB5脱色62.34%,24h可完成90%以上的脱色效果。     

阿魏菇与胶红酵母共培养产漆酶对活性艳蓝W-RV的脱色

利用阿魏菇与胶红酵母共培养所产漆酶对染料活性艳蓝W-RV进行脱色,同时考察不同p H、温度、染料浓度和漆酶酶活等条件对脱色的影响。结果显示,酸性范围内的p H有利于活性艳蓝W-RV的脱色,较高温度并不适于脱色反应。在研究不同染料浓度的影响时发现,不同浓度染料的脱色率在7 h反应后都达到了稳定,而漆酶酶活在达到200 U/L后脱色率不再变化。因此,最终得到的最适反应条件为p H 4.5、30℃、染料质量浓度100 mg/L、漆酶酶活200 U/L,在此条件下,活性艳蓝W-RV的最高脱色率为89.91%。     

疣孢漆斑菌Myrothecium verrucaria GH-01漆酶的纯化和酶学性质研究

疣孢漆斑菌具有生长周期短,分泌漆酶酶活高等特点。利用已分离得到的疣孢漆斑菌GH-01(Myrothecium verrucaria GH-01)发酵产生粗酶液。进而通过分级沉淀、透析和层析的方法对漆酶粗酶液进行纯化。SDS-PAGE和Native-PAGE结果表明纯化可获得具有漆酶活性的单体蛋白。酶学性质研究表明,该漆酶催化最适温度为40℃,在底物ABTS存在条件下的最适p H值为4.0,且在低温及碱性条件具有较好的稳定性。此外通过漆酶对4大类染料脱色能力的研究,发现该漆酶对偶氮类的橙黄Ⅰ和蒽醌类的茜素红脱色有较好的脱色效果,反应1 h脱色率达80%以上;对三苯甲烷类的碱性品红脱色能力较弱,脱色率只能达到20%左右;脱色率最差的是杂环类的亚甲基蓝。在含10 U漆酶的体系中,对50 mg/L的染料降解效果相对最佳。     

固定化漆酶对染料酸性紫43的脱色和降解

采用自制复合型载体丙烯酸酯类聚合物固定的漆酶对染料酸性紫43进行脱色处理。研究了固定化酶的用量、底物浓度、温度、pH对其降解效果的影响。结果表明,固定化漆酶脱色降解酸性紫43的适宜条件为:酶用量12.5 U/mL,染料浓度150 mg/L,反应的温度范围在45~55℃,pH值范围在4.5~5.0。在上述条件下降解4h,染料酸性紫43脱色率能达到98.5%。重复分批使用固定化漆酶处理染料酸性紫43,在使用8批次后,脱色率仍然能保持在90%以上,其催化效率得到了很大提高。     

栓菌420漆酶C基因的克隆、高效表达及重组酶的染料脱色潜能

根据漆酶铜结合保守区氨基酸序列设计简并引物,从新型漆酶合成菌株栓菌420(Trametes sp.420)基因组DNA扩增得到一新的漆酶同工酶基因(lacC)片段,应用长距离反向PCR技术获得其两端侧翼序列。克隆得到的lacC序列长3640bp,包括长2263bp的开放读码框及5′和3′-非编码区。lacC cDNA序列长1560bp,编码一519aa的多肽。推导的LacC蛋白序列内部存在有10个潜在的N-糖基化位点和4个铜原子结合区。将不含自身信号序列的lacC cDNA以pPIC9载体为媒介克隆到表达载体pPIC9K上,转化毕赤酵母(Pichiapastoris)GS115细胞。重组菌在含有0.3mmol/LCuSO4和0.8%丙氨酸的BMM培养基中20℃培养9d,重组漆酶(rLacC)产量达到1.62×104U/L。用发酵粗酶液对终浓度50mg/L的染料进行脱色实验,结果表明,6U/L的rLacC对测试的三甲基类和偶氮类染料具有良好的脱色作用,小分子介体ABTS和HBT能够提高rLacC对染料的脱色效率和脱色速度。     

一色齿毛菌漆酶的酶学特性及染料脱色研究

染料由于具有复杂的化学结构通常难以降解。本文从白腐菌一色齿毛菌LS0547中纯化出胞外漆酶并用于染料脱色实验。SDS-PAGE结果显示纯化的漆酶分子量大小为63.7kDa。漆酶氧化底物ABTS的最适pH为2.2,最适温度为50℃。叠氮钠可强烈抑制漆酶活性,半胱氨酸和二硫苏糖醇可部分抑制漆酶活性。漆酶氧化ABTS,丁香醛连氮和2,6-二甲氧基苯酚的米氏常数分别为0.217,0.306和0.199mmol/L。粗酶和纯化的漆酶用于不同化学结构的染料的脱色研究,结果表明一色齿毛菌纯化漆酶可快速对RB亮蓝进行脱色,偶氮胭脂红和结晶紫的脱色效果低于RB亮蓝,测试的三种染料均可在没有介体存在的条件下被漆酶脱色,显示出一色齿毛菌漆酶在染料废水处理中的应用前景。     

刺芹侧耳产漆酶条件优化及对偶氮染料甲基橙的脱色

漆酶是一种含铜的单电子多酚氧化酶,能够催化氧化各种酚类及多种染料,在处理染料废水方面具有巨大的潜力。刺芹侧耳Pleurotus eryngii具有较强的产漆酶能力,但漆酶产量在较大程度上受环境条件限制。本文研究了氮源含量、pH、温度、金属离子等环境条件对刺芹侧耳产漆酶能力的影响,优化了其产漆酶条件,并用其粗酶液对典型偶氮类染料甲基橙进行脱色,结果表明,在氮源0.5%（W/W）、pH 5.5、温度28℃、添加5.0mmol/L Mg ²⁺的培养条件下,刺芹侧耳产漆酶能力最强,培养6d时,漆酶酶活可达78.0U/L。用优化培养的刺芹侧耳粗酶液对偶氮染料甲基橙进行脱色,28h后脱色率可达90%,脱色反应为准一级动力学反应,甲基橙并未完全矿化,而是生成小分子中间产物。     

不同培养基对富集筛选脱色真菌菌群的效果比较

利用活性黑RB5和活性红M-3BE作为筛选因子,从染料脱色效果、菌群产酶能力以及菌群中的微生物丰富度三方面比较了酵母培养基A、产漆酶真菌培养基B和白腐真菌培养基D在脱色真菌富集筛选方面的效果。富集筛选结果共得到11组具有明显脱色效果的真菌菌群,其中5组来自于D培养基,A和B培养基各获得3组。来自A培养基的3组菌群显示出最好的脱色效果和最大的菌群丰富度,对50mg/L的活性红M-3BE和酸性红A溶液的脱色率最高达到99.53%和97.42%,从中分离到了16株真菌,初步鉴定分属于水霉科、曲霉科(红曲霉属)、节壶菌科和白粉菌科;而B和D培养基中所获得的菌群脱色效果稍差,从中仅得到3株和2株真菌,初步鉴定属于酵母和青霉。A、B两种培养基在各种染料存在下更易产生木质素过氧化物酶,产漆酶能力较弱,而D培养基产漆酶活性较高。     

灵芝漆酶催化直接耐晒翠蓝GL脱色条件的优化

采用灵芝菌株发酵所得的漆酶, 对酞菁类染料直接耐晒翠蓝GL进行了催化脱色实验, 确定了脱色反应的最适条件。结果表明: 单独使用灵芝漆酶粗酶液对直接耐晒翠蓝GL具有很好的脱色效果。其最适脱色pH为3.0, 最适脱色温度为40°C, 最适漆酶用量是40 U/mL, 最适染料浓度为60 mg/L。以上述最适脱色条件对直接耐晒翠蓝GL进行脱色实验, 反应70 min, 脱色率可达94.3%。研究结果显示, 所试灵芝漆酶在印染废水治理方面具有良好的应用前景。     

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.