苦豆子生物碱对萝卜蚜的毒力及其对几种酯酶的影响

苦豆子Sophora alopecuroids(L.)的次生代谢物质为喹诺里西定生物碱类。本研究明确了该生物碱中的野靛碱对萝卜蚜(Lipaphis erysimi)有很高的毒杀作用,对其无翅成蚜的致死中浓度(LC₅₀浸渍法)为(432.59±2.12)mg/L,优于著名的杀蚜生物碱毒黎碱和烟碱,两者对该试虫的LC₅₀分别为(684.70±2.28)mg/L和(1090.65±2.01)mg/L。用小菜蛾(Plutella xylostella)幼虫作试虫,得知苦豆子7种主要生物碱对昆虫的乙酰胆碱酯酶(AChE)有抑制作用,其抑制程度排序为：总碱>野靛碱>槐胺碱>槐定碱>槐果碱>氧化苦参碱>苦参碱>苦豆碱。野靛碱和苦豆碱对a-乙酸萘酯酶、a-乙酸萘酯羧酸酯酶及酯酶同功酶的活性亦表现不同程度的抑制作用。     

苦豆子生物碱对小菜蛾体内部分杀虫剂代谢酶活性的影响

以苦豆子Sophora alopecuroids 7种生物碱和小菜蛾Plutella xylostella幼虫为试材,研究了该生物碱对小菜蛾体内降解杀虫剂的羧酸酯酶、磷酸酯酶、谷胱甘肽-S-转移酶活性的影响。结果表明: 野靛碱和苦豆碱对羧酸酯酶活性有显著的抑制,为可逆抑制类型的非竞争性抑制作用;野靛碱等5种生物碱对酸性磷酸酯酶有明显的抑制,野靛碱对碱性磷酸酯酶有弱抑制作用;其中野靛碱等3种生物碱对谷胱甘肽-S-转移酶有明显的抑制作用。     

苦豆子提取物及其7种生物碱单体对埃玛菌素的增效作用

以苦豆子（Sophora alopecuroids L．）种子的甲醇提取物、水提取物及其7种生物碱单体和小菜蛾（Plutella xylostella）幼虫为试材,对生物源杀虫剂埃玛菌素进行增效作用研究。结果表明,7种生物碱单体对埃玛菌素增效比值为1．013～1．565。其中,苦豆碱和槐胺碱的增效作用最为明显,增效比值分别为1．565和1．413;而苦参碱和槐定碱对埃玛菌素的增效作用较差,增效比值仅为1．138和1．013,这2种生物碱单体对埃玛菌素仅表现出联合作用。苦豆子甲醇提取物和水提取物对埃玛菌素增效活性大于各生物碱单体,增效比值分别为3．443和2．027。     

几种苦豆子生物碱对小菜蛾部分生理指标的影响

四龄小菜蛾幼虫经苦豆子7种生物碱处理后,表现呼吸强度增加,完成完整呼吸次数减少,其中,苦参碱、苦豆碱和槐胺碱均显著促进试虫二氧化碳释放量和释放过程。槐果碱处理试虫体内总糖含量显符降低。所有处理试虫的生长发育均显著受到抑制。     

苦豆子生物碱抗烟曲霉、须癣毛癣菌和新生隐球菌的作用研究

目的对比研究苦豆子总碱、槐果碱、苦参碱、槐定碱、氧化苦参碱体外抗烟曲霉、须癣毛癣菌和新生隐球菌的敏感性,为苦豆子进一步开发利用奠定基础。方法分别用管碟扩散法和微量液基稀释法,测定苦豆子总碱、槐果碱、苦参碱、槐定碱、氧化苦参碱对烟曲霉、须癣毛癣菌和新生隐球菌的抗菌活性。结果管碟法显示上述5种生物碱体外对烟曲霉、须癣毛癣菌和新生隐球菌均有不同程度的抗菌活性。前4种生物碱对烟曲霉的最低杀菌浓度(MFC)分别为25.0、4.25、5.0、3.125 mg·mL~(-1),氧化苦参碱对烟曲霉MFC500 mg·mL~(-1);对须癣毛癣菌的MFC分别为3.125、2.125、5.0、1.5625、125 mg·mL~(-1);对新生隐球菌的MFC分别为3.125、4.25、10、6.25、1000 mg·mL~(-1)。结论槐果碱、苦参碱及槐定碱其抗真菌活性与苦豆子总碱相当,氧化苦参碱的作用不显著。     

苦豆子的抗生成分

苦豆子茎叶水提取液对小麦幼芽、幼根的生长表现出明显的抑制作用。水溶液含有苦豆碱,槐定和槐果碱。实验表明,当这些生物碱作用于小麦幼苗时,引起强烈的抑制作用,结果如下:(1)苦豆子水提取液对小麦幼苗的生长有强烈的抑制作用,对幼芽的最低抑制浓度为5％,对幼根的最低抑制浓度为0.1％。(2)薄层层析实验表明,水溶液中苦豆碱、槐定和槐果碱为主要抑制成分,它们可被小麦幼根吸收,但不能传入幼芽中。(3)苦豆碱的抑制作用大于槐定和槐果碱。它们的最低抑制浓度分别为8.6×10~(-5) M、2.0×10~(-3)和2.0×10~(-3)至8.1×10~(-4)M。3种生物碱对幼根的抑制作用大于对幼芽的抑制作用。(4)根据含量测定,在相同浓度作用下,苦豆碱在小麦幼根根尖中的含量均比槐定和槐果碱高,表明苦豆碱容易被小麦幼根吸收。同时,苦豆碱的毒性大于槐定和槐果碱。     

苦豆子中生物碱的分布及其在生长期内的含量变化

采用高效液相仪测定苦豆子植株不同部位和不同生长期间的生物碱含量。结果表明：苦豆子植株不同部位的总生物碱含量为21.346-41mg．g-1（DW）,以种子中为最高,花、根、果皮、根状茎、叶片、地上茎次之,复叶轴中最低;苦参碱含量为0．55-1．30m2．g-1（DW）,含量由高到低依次为种子〉花〉根〉果皮〉根状茎〉叶片〉地上茎〉复叶轴;氧化苦参碱和氧化槐果碱含量分别为3．76～12．29mg．g-1（DW）和3．36—13．33mg·g-1（DW）,这2种生物碱含量由高到低依次为种子〉花〉根〉果皮〉根状茎〉地上茎〉复叶轴〉叶片：根、根状茎、地上茎、叶中的苦参碱、氧化苦参碱和氧化槐果碱含量在7月份达到峰值;总生物碱含量在8月达到峰值。     

半夏和苦豆子生物碱的抗线虫活性

首次研究了半夏和苦豆子生物总碱,以及3种主要的苦豆子单体生物碱(槐定碱、氧化苦参碱和氧化槐果碱)的抗线虫活性。半夏生物总碱处理24 h,对松材线虫、南方根结线虫、全齿复合线虫和秀丽隐杆线虫的半抑制浓度(IC50)分别为16.18、20.25、33.24和20.77μg/m L。苦豆子生物总碱处理24 h,对上述4种线虫表现出更强的抑制活性,IC50值分别为0.622、0.383、1.476和1.224μg/m L,抗线虫活性强于或接近阳性对照阿维菌素。3种苦豆子单体生物碱均表现出明显的抗线虫活性,其中氧化槐果碱的抗线虫活性最强。研究结果为植物源杀线虫剂的研究和开发提供了依据。     

苦参生物碱的研究

从苦参(Sophora flavescens Ait)根中分离得到9个生物碱,用波谱等方法确定为槐果碱(sophocarpine)、苦参碱(matrine)、异苦参碱(isomatrine)、槐醇(sophoranol)、N-甲基野靛碱(N-methylcytisine)、槐定(sophoridine)、氧化苦参碱(oxymatrine)、氧化槐果碱(oxysophocarpine)和氧化槐醇(sophoranol N-oxide)。其中氧化槐醇是首次从苦参根中得到的。     

苦参碱类生物碱的应用进展

苦参碱是豆科植物苦参、苦豆子、广豆根等中草药的活性成分,是苦参碱类生物碱的代表,这一类生物碱主要还包括氧化苦参碱、槐果碱、氧化槐果碱、槐定碱和槐胺碱等。而对苦参碱和氧化苦参碱的研究最为广泛。苦参碱对中枢神经具有解热、镇痛、抗惊厥、稳定神经等作用;对心血管系统具有明显的负性频率和正性肌力作用、能防治动脉粥样硬化、减轻心肌损伤等作用;对消化系统具有抗肝损伤、抗纤维化、升高白细胞等作用;还具有抗肿瘤、抗肝癌等作用。氧化苦参碱用于治疗白细胞低下和慢性乙型、丙型肝炎、阻止肝纤维化和肝硬化,有抗心律失常、强心、平喘等作用。槐果碱有明显抗柯萨奇B病毒(Coxsackie Virus B,CVB)的作用、免疫调节功能以及抗严重急性呼吸道综合症(Severe Acute Respiratory Syndrome,SARS)病毒的作用。槐定碱有改善心功能、抗炎、抗肿瘤、抗病毒作用。槐胺碱具有免疫抑制、抗心律失常作用。本文综述了这一类生物碱的成分分析及其部分化合物的药理活性和临床应用等方面的研究进展。     

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.