毛脉酸模内生真菌蒽醌类次生代谢产物的筛选及含量分析

本文通过对毛脉酸模内生真菌的发酵培养得到其次生代谢产物,采用HPLC法对内生真菌中蒽醌类成分进行筛选。以大黄素、大黄酸、大黄酚、大黄素甲醚、芦荟大黄素五种蒽醌类成分为参照,筛选出3株真菌含大黄素、3株真菌含大黄酸、5株真菌含芦荟大黄素,其中含量最高为683μg/g、最低为8μg/g。将各菌株所含成分与各菌株分离部位的相应成分进行比较,相对宿主植物而言各菌株均有较高的含量。本实验分析方法准确、快捷,适用于毛脉酸模内生真菌的代谢产物研究。     

链霉菌原生质体种间融合提高细胞分裂素效价的研究

本文报道粉红孢类群的泾阳链霉菌与淡紫灰链霉菌不液化亚种的原生质体种间融合重组的结果。利用单亲灭活和双亲株的遗传标记筛选细胞分裂素的融合子,融合率为 10-4—10-2。在所得的融合菌株中,F1211菌株的CTK效价为292μg/L,F1613的CTK效价为857μg／L,比低产原始亲株提高2—7倍,比高产亲株提高0.3--3.0倍。在电子显微镜下观察到融合过程。     

番茄煤霉病生防融合子基因组RAPD分析鉴定

RAPD分子标记以其快速、简便等优点,克服了传统的标记手段和形态分类学的缺点,在亲本和杂交种的鉴别以及在基因克隆与分离和遗传图谱的建立等研究中都起着重要的作用。以番茄煤霉病生防菌株木霉菌T-23和链霉菌A的融合子为实验材料,比较和研究了真菌融合子基因组DNA的提取。并用20个随机引物对亲本及其融合子进行RAPD分析。结果表明,SDS-CTAB法提取的基因组DNAOD260/OD280为1.909,DNA浓度约为42.0 ng/μL,可以满足分子生物学实验的需要;融合子是双亲融合的产物,但从双亲获得的遗传信息不等,融合子在DNA水平上更接近链霉菌。     

河南太行红豆杉产紫杉醇内生真菌的筛选

目的：筛选出高产紫杉醇的内生菌株,为发酵生产紫杉醇提供菌种。方法：从不同来源的红豆杉根、茎、叶中分别分离内生真菌,并对其进行发酵,用HPLC法对菌丝体和发酵液中的紫杉醇含量进行检测,获得高产菌株。结果：获得54株产紫杉醇的内生真菌,其中根、茎、叶分别为29株、16株、9株。根、茎、叶三部位产紫杉醇菌株的平均产量分别为248.57μg/L、149.09μg/L、104.94μg/L;其中一株产量高达622.75μg/L。结论：从野生红豆杉的根部分离内生真菌效果较好,并获得了一株高产菌株。     

核桃内生真菌抗氧化菌株的筛选及其代谢产物活性研究

本试验以29株核桃内生真菌为研究对象,采用总还原力(FRAP法)及DPPH·清除试验评价其代谢产物的抗氧化能力,从中筛选出高活性菌株,并对该菌株发酵液进行浓缩萃取,研究各萃取物的抗氧化活性。结果表明,供试29株菌的代谢产物都表现出一定的抗氧化活性,其中菌株LTS-6-6(Pyrenochaeta)为高活性菌株。该菌株发酵液乙酸乙酯萃取物(EAE)显示了较强的抗氧化活性,对DPPH·的EC_(50)为7μg/mL,总还原力为527.59±10.66 mg V_C/g,总酚和总黄酮含量分别达到641.14±7.50 mg没食子酸/g、100.30±8.44 mg芦丁/g。该结果表明,核桃内生真菌代谢产物具有一定的抗氧化活性,是寻找天然抗氧化活性物质的良好资源。     

链霉菌菌株A与哈茨木霉T-23原生质体融合条件的研究

报道了链霉菌菌株和哈茨木霉菌株属问原生质体融合构建生防工程菌的前期研究成果,研究结果显示：链霉菌菌株A与哈茨木霉T-23分别以1000μg／ml庆大霉素和50～53℃热灭活120min作为遗传标记;融合系统采用聚乙二醇(PEG)作为促融剂,通过对PEG最佳分子量、浓度、处理时间的筛选,确立最佳融合技术系统,即内含0．05mol／L Ca^2 的35％ PEG6000,融合处理15min。所得融合子经过选择再生培养基培养后,在132株融合子中初步筛选出2株稳定的融合子。经孢子大小和DNA含量测定,确立一株为单倍重组体,另一株为杂合二倍体。     

共附生微生物抗肿瘤活性菌的筛选与鉴定

对分离自海绵和植物组织的一些微生物进行抗肿瘤活性菌株的筛选。采用SRB法对252株微生物菌株的发酵提取物进行了抗肿瘤活性的筛选。结果显示,28%的测试菌株在提取物浓度为100μg/mL时对HeLa细胞的抑制率在50%以上,经复筛确定有6株细菌和1株真菌具有良好且稳定的抗肿瘤活性,其提取物在100μg/mL时对HeLa细胞的抑制率均在80%以上,其中活性最高的两株菌HMJ-390和YX-5对HeLa细胞的IC50分别为40.56μg/mL和5.33μg/mL。经16S rDNA和ITS rDNA序列分析,鉴定HMJ-390为Cellulophagasp.,YX-5为Aspergillussp.。结果表明,作为抗肿瘤药物的潜在来源共附生微生物值得关注。     

运用萎锈灵抗性基因构建香菇聚乙二醇介导的遗传转化方法

【背景】萎锈灵抗性基因作为筛选标记在植物和真菌中得到广泛应用。【目的】构建可以使用萎锈灵作为筛选标记的香菇遗传转化技术。【方法】利用溶壁酶消化培养4 d的香菇菌株411-4的菌丝体获得原生质体,加入适量pL-cbx质粒和聚乙二醇溶液,混合物涂布于再生筛选培养基上,培养后挑选菌落进行验证试验。【结果】在原生质体数目108个和添加4μg质粒DNA的情况下,得到了40个抗性转化子。利用PCR实验和转代实验对转化子进行验证,结果显示38个转化子的抗性可稳定遗传,表明萎锈灵抗性基因整合进入了供试菌株的基因组中。【结论】利用香菇411-4菌株建立了一套运用萎锈灵抗性基因作为分子标记的遗传转化技术体系。     

荧光标记香菇原生质体融合菌株的鉴定

以异硫氰基荧光素（FITC）标记和香菇单核L4菌株的原生质体和未经标记的香菇单核B14菌株的原生质体为亲本,在聚乙二醇（PEG）的促融下进行融合,选取一个带有荧光,另一个不带荧光的原生质体粘合对进行再生培养,通过对利用“锁状联合”筛选得到的菌株进行鉴定后表明：融合菌株为双核菌丝,与双亲产生明显拮抗,其酯酶同工酶及可溶性蛋白质凝胶电泳图谱分析表明融合菌株均与双亲有区别,经琼脂平板快速出菇及出菇实验证明融合菌株出菇早,产量有所提高。     

酿酒酵母原生质体融合及其融合子的鉴定

应用原生质体融合技术,得到乙醇产量较高的两株多倍体酵母菌融合子F_(28)和F_(38),融合频率为2×10~(-5)。测定融合子F_(28)、F_(38)每个细胞内DNA含量分别为2.14×10~(-8)、2.34×10~(-8)μg,而亲株DNA含量分别为0.78×10~(-8)和1.24×10~(-8)μg。并进行了融合子细胞增殖率、乙醇发酵能力及同功酶分析等试验。用固定化细胞发酵乙醇试验结果表明,在pH4.0,17％糖蜜为基质情况下,发酵3小时,融合子F_(28)、F_(38)的乙醇产量分别为77.21和77.09mg/ml;亲株乙醇产量仅为65.00mg/ml和68.40mg/ml。为固定化细胞发酵乙醇提供优良菌株。     

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.