双歧杆菌发酵对豆芽汁中大豆异黄酮含量及组分影响的研究

目的探讨双歧杆菌发酵对豆芽汁中大豆异黄酮含量及组分影响.方法采用HPLC法检测波长260 nm,测定豆芽汁中金省异黄素、大豆黄素的含量.结果表明通过发酵处理后,豆浆中总大豆异黄酮浓度没有明显的变化(P＞0.05);大豆异黄酮甙元的浓度较未经过发酵处理的豆浆组明显增加(P＜0.05);而大豆异黄酮糖甙的浓度却明显降低(P＜0.05).结论豆浆中的大豆异黄酮糖甙在双歧杆菌的β葡萄糖苷酶作用下水解为异黄酮甙元,异常酮甙元的浓度显著增加.     

产漆酶真菌的筛选及其固态发酵条件研究

用愈创木酚平板法对14株白腐真菌进行初筛,通过测定漆酶活力进行复筛,筛选出1株生活力较强,产漆酶活力高的菌株MZ-1,经ITS-5.8S rDNA序列分析,初步鉴定为Trametes versicolor。在固态发酵培养基的基础上,对该菌株产漆酶的培养基组成进行正交优化,得到最优发酵培养基:麸皮∶秸秆粉∶豆粕∶玉米粉为3∶3∶2∶1,可溶性淀粉2%,(NH4)2SO4+蛋白胨1%,KH2PO40.1%,料水比1∶2。接种4个菌塞,温度为30℃,发酵8 d后酶活可达到1 555.57 U/g。     

烟草节杆菌肌酐酶发酵培养基优化

对烟草节杆菌发酵产酶培养基进行了优化。在烟草节杆菌的初始发酵培养基条件下,肌酐酶初始酶活仅为9.2U/g湿菌。首先,通过肌酸诱导、金属离子筛选实验发现肌酸和金属离子对烟草节杆菌产肌酐酶酶活有重要影响;然后再通过碳源和氮源优化,以玉米浆和酵母膏作为复合氮源,可溶性淀粉为碳源,肌酐酶产量可达到108.5 U/g湿菌;在以上基础上,最后通过两次正交试验优化初始发酵培养基,最优培养基组成为:肌酸0.3%,玉米浆0.3%,可溶性淀粉0.4%,酵母膏0.7%,Fe~2+0.003%,Mn~2+0.006%,Mg~2+0.005%,K_2HPO_40.1%,KCl 0.5%。在优化后的发酵培养基条件下,烟草节杆菌肌酐酶酶活达到182.82 U/g湿菌,为初始发酵培养基酶活的19.87倍。     

产腈水解酶基因工程菌的产酶诱导条件及培养基优化

本文通过对产酶诱导条件及发酵培养基进行优化,成功提高了产腈水解酶基因工程菌E. coli BL21(DE3)-pETNYNit的产酶水平。研究结果显示,最佳发酵培养基为：葡萄糖0.2%、甘油0.7%(v/v)、蛋白胨1.2%、酵母膏0.8%、NaCl 0.3%、(NH4)2SO40.3%、NH4Cl 0.13%、Na2 HPO4·12H2 O 1.04%、KH2 PO40.39%、MgSO4·7H2 O 0.03%,pH 7.2。最佳产酶诱导条件为：发酵4 h时加入0.5 mmol/L IPTG,然后在28℃、240 r/min下诱导腈水解酶基因表达14 h~16 h。采用优化方案,重组菌产酶水平可提升至0.9~1×105 U,与野生菌株的产酶水平相比,提高幅度超过50%。同时重组菌培养仅需24 h,培养周期缩短超过50 h。     

豆粕营养成分对蝙蝠蛾拟青霉发酵产物的影响

为探索培养基中的豆粕以及制备豆粕的原材料大豆对蝙蝠蛾拟青霉发酵产物的影响,我们比较了不同品种大豆和用其制成的豆粕的主要营养成分含量,包括粗蛋白、粗脂肪、6种微量元素（钙、镁、铜、锌、铁、锰）和总异黄酮（大豆苷、黄豆黄苷、染料木苷、大豆苷元、黄豆黄素、染料木素）,以及豆粕作为培养基对蝙蝠蛾拟青霉发酵产物的生物量和有效成分含量包括腺苷、腺嘌呤、虫草素和麦角甾醇的影响,结果表明大豆中钙和大豆苷与发酵产物中腺苷含量正相关。豆粕中钙、大豆苷、大豆苷元、染料木素与发酵产物中腺苷含量正相关;豆粕中钙、镁、大豆苷、大豆苷元、染料木素、总异黄酮与发酵产物中腺嘌呤含量负相关;豆粕中铁与菌丝体干重值正相关。结果表明,培养基中的豆粕和原料大豆主要营养成分含量对蝙蝠蛾拟青霉发酵产物品质有显著影响。     

产碱性纤维素酶嗜碱芽孢杆菌AH-8的研究

从贵州、云南、海南、安徽、四川、辽宁等地采集碱性土样,分离筛选到1株能稳定的产生碱性纤维素酶的嗜碱性芽孢杆菌AH-8。研究表明,该菌株最适产酶温度为37℃,最适发酵时间为36 h;采用均匀设计法对其发酵培养基进行优化,优化培养基配方(%):淀粉3.0,胰蛋白胨1.5,牛肉膏1.5,葡萄糖0.3,KH2PO40.1,初始pH 10.0。在优化培养基条件下,其产酶量提高了120%。碱性纤维素酶最适反应温度为60℃;最适反应pH 10.0;0.01%Co2 对酶活力有一定激活作用。     

Agrobacterium tumefaciens OAH-01产脲酶发酵培养基优化

氨基甲酸乙酯( EC)是大多数发酵制品中的潜在致癌物,而尿素是EC的最主要前体物质之一,因此需要采取相关措施控制发酵制品中尿素的含量。向酒体中添加脲酶具有安全、高效和处理条件温和等优点,是FDA推荐的降低EC 含量的优先方法。微生物是脲酶的主要来源,可利用其实现脲酶的大规模生产。本文以产脲酶根癌农杆菌Agrobacterium tumefaciens OAH-01为研究对象,考察了该菌株的生长曲线和产酶曲线,证明该菌株产脲酶属生长关联型,且能在较短时间内达到最大产酶量,此外还研究了发酵培养基组成对该菌发酵产酶的影响,通过单因素及正交试验优化确定了最佳发酵培养基组成(g/L)：蛋白胨20,酵母粉5,葡萄糖5,FeCl30.54,Na2HPO40.5, KH2 PO40.5,NiSO40.1,起始 pH 7.0。在最适条件下发酵16 h,菌悬液中脲酶酶活可达1.077 U/mL,为优化前的2.4倍。超声破碎后细胞上清中的脲酶活性为0.419 U/mL,为优化前的4.4倍。     

酵母产γ-氨基丁酸发酵培养基的优化

目的：提高酵母产γ-氨基丁酸的能力。方法：采用单因素及正交设计实验对酵母产γ-氨基丁酸（GABA）的培养基进行优化。结果：确定最适碳源为葡萄糖,最佳氮源为蛋白胨和硫酸铵复合氮源,合适的无机盐为KH2PO4;最佳发酵培养基为3%葡萄糖,3%蛋白胨,0.3%（NH4）2SO4和0.1%KH2PO4。在此培养条件下,摇瓶发酵可以获得1.690g.L-1的GABA产量。结论：发酵培养基的优化,提高了菌株产γ-氨基丁酸的能力。     

甲壳素脱乙酰酶产生菌产酶条件的优化

采用斜面培养和液体发酵培养产甲壳素脱乙酰酶的真菌构巢曲霉,并且研究了产酶条件。结果表明,构巢曲霉的最适产酶条件为：发酵培养基初始pH值为6.5、发酵时间为96h、培养温度为31℃、碳源浓度为2%、氮源浓度为2%、金属离子浓度为0.01mol/L、接种量为6%。     

5′—磷酸二酯酶高产菌株的选育和发酵培养条件的优点

以ATCC14994为出发菌株,采用紫外线与亚硝基胍相结合的多次诱变育种,获得1株5′-磷酸二酯酶高产菌株HAT2228.通过单因子和正交试验对该菌株的产酶发酵条件进行了优化,优化发酵产酶条件为蔗糖5%,酵母膏0 3%,蛋白胨0.3%,K2HPO4 0.8%,KH2PO40.8%,MgSO4 0.2%,ZnSO4 0.2%,培养基起始pH6 0,接种量10%,培养温度30℃,摇床转速120r/min,发酵时间48h.在优化条件下,HAT2228的产酶水平达1 329u/ml.     

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.