肾蕨配子体发育的研究

利用光学显微镜观察肾蕨(Nephrolepis auriculata)孢子的萌发及配子体发育过程。结果表明:成熟的孢子棕黄色,不透明,极面观圆球形,赤道面观豆形,单裂缝,表面光滑。孢子萌发类型为书带蕨型,播种后15 d左右萌发,形成5-12个细胞长的丝状体。原叶体发育为三叉蕨型。30 d左右发育为片状体,45 d左右形成幼原叶体,幼原叶体不对称,成熟原叶体心脏形对称。原叶体边缘及背腹面都具毛状体,毛状体由单细胞构成。60 d左右精子器开始出现,精子器近圆球形,由3个细胞构成。70 d左右颈卵器出现,成熟颈卵器颈部由4列细胞构成,3-5层细胞高。原叶体受精后1个月内可看到幼胚生成。     

球腺肿足蕨的配子体发育特征及其系统学意义

采用改良Knop’s营养液液体和固体培养基,对球腺肿足蕨的孢子进行人工培养,利用光学显微镜观察其孢子的萌发及配子体发育过程。结果表明:成熟的孢子深褐色,不透明,极面观为椭圆形,赤道面观为豆形,单裂缝,周壁具密集的波纹状褶皱。孢子萌发类型为书带蕨型,原叶体发育类型为三叉蕨型。孢子接种后7d左右萌发,30d左右形成为片状体,50d左右发育为幼原叶体,幼原叶体不对称,但成熟原叶体心脏形对称。原叶体边缘及背腹面都具乳头状毛状体。75d左右精子器出现,精子器近圆球形,由3个细胞构成。90d左右颈卵器出现,成熟颈卵器颈部由4～5列细胞构成,3～5层细胞高。原叶体受精后1个月内可看到幼孢子体生成。最后讨论其系统学意义。     

四回毛枝蕨配子体发育的研究

采用MS培养基培养四回毛枝蕨孢子,利用光学显微镜详细观察记录了其孢子萌发、配子体发育及幼孢子体形成的整个过程。结果表明:成熟的孢子黑褐色,不透明,极面观圆球形,赤道面观蚕豆型,单裂缝,表面微褶皱。播种后8d左右萌发,萌发类型为书带蕨型,配子体发育为三叉蕨型。播种20d左右发育为片状体。播种30d左右形成幼原叶体,幼原叶体暂不对称,成熟原叶体呈蝴蝶形。原叶体边缘及背腹面都具毛状体,数量丰富,单细胞。播种50d左右开始有性器官出现,精子器近圆球形,由3细胞构成,成熟颈卵器颈部由5列细胞构成。原叶体受精后1月内可看到幼胚生成。     

槲蕨配子体形态发育的研究

用无机培养基和土壤培养基分别培养槲蕨(Drynaria roosii Nakaike)孢子,显微镜下观察孢子萌发及配子体形态发育过程.结果表明:孢子黄色,具单裂缝,赤道面观豆形,极面观椭圆形,不具周壁,孢子外壁局部具大小不一的颗粒状纹饰.接种后10～12 d孢子萌发,萌发类型为书带蕨型,原叶体发育为槲蕨型.接种后20 d左右发育为片状体,片状体形成顶端细胞的时间较晚.毛状体出现在片状体形成之后,数量丰富,多为单细胞,分布于原叶体背腹面及边缘.接种后60 d左右发育形成幼原叶体,成熟原叶体呈心脏形.接种后65 d左右开始有性器官出现,精子器的出现较颈卵器早10 d左右.颈卵器成熟后,颈部常向原叶体基部倾斜或弯曲.原叶体受精后幼胚突破颈卵器生长.     

日本蹄盖蕨配子体发育的研究

采用混和土培养日本蹄盖蕨(Athyrium niponicum)孢子,显微镜下观察记录其孢子萌发及配子体发育过程。结果表明:孢子黑褐色,赤道面豆形,极面观椭圆形,单裂缝。播种7 d左右孢子萌发,萌发类型为向心型,配子体发育为铁线蕨型。丝状体7~11细胞时开始发育为片状体。播种14 d后发育形成幼原叶体,成熟原叶体呈心脏形。原叶体边缘可产生单细胞毛状体。播种后20 d左右精子器出现,精子器近圆球形,由3细胞组成。7 d后颈卵器出现,成熟颈卵器3~5层细胞高。精卵受精后14 d左右即可观察到从原叶体上生成的幼胚。     

乌毛蕨配子体发育的研究

采用混合土培养乌毛蕨（Blechnum orientale）孢子,显微镜下观察记录其孢子萌发及配子体发育过程。结果表明：孢子黑褐色,赤道而豆形,极而观椭圆形,单裂缝。播种1周左右孢子萌发,萌发类型为书带蕨型,配子体发育为叉蕨型。丝状体5—10细胞时开始发育为片状体。播种2周后发育形成幼原叶体,成熟原叶体呈心脏形。原叶体边缘及表面均可产生毛状体,数量丰富,为单细胞。播种后1个月左右开始有颈卵器出现,成熟颈卵器颈部由4列细胞组成,3—5层细胞高。精子器产,扛时间较颈卵器早10d左右,精子器近圆球形,由3细胞组成。精卵受精后2周左右即可观察到从原叶体上生成的幼胚。     

江南星蕨配子体形态发育的研究

用无机培养基和土壤培养基分别培养江南星蕨(Microsorium fortunei(Moore)Ching)孢子,显微镜下观察记录其孢子萌发及配子体形态发育过程.结果表明:孢子黄色,赤道面观豆形,极面观椭圆形,单裂缝,外壁具刺状纹饰.接种后7～12d孢子萌发,萌发类型为书带蕨型,配子体发育为槲蕨型.接种后25 d左右发育为片状体,片状体形成顶端细胞的时间较晚,有的甚至不形成.无机培养基培养的原叶体常在基部发生营养繁殖.毛状体出现在片状体形成之后,数量丰富,多为单细胞,分布于原叶体背腹面及边缘.接种后60 d左右发育形成幼原叶体,成熟原叶体呈心脏形.接种后80 d左右开始有性器官出现,精子器的出现较颈卵器早10d左右.颈卵器成熟后,颈部常向原叶体基部倾斜或弯曲.     

江南星蕨配子体形态发育的研究

用无机培养基和土壤培养基分别培养江南星蕨(Microsorium fortunei (Moore) Ching)孢子,显微镜下观察记录其孢子萌发及配子体形态发育过程。结果表明：孢子黄色,赤道面观豆形,极面观椭圆形,单裂缝,外壁具刺状纹饰。接种后7～12 d孢子萌发,萌发类型为书带蕨型,配子体发育为槲蕨型。接种后25 d左右发育为片状体,片状体形成顶端细胞的时间较晚,有的甚至不形成。无机培养基培养的原叶体常在基部发生营养繁殖。毛状体出现在片状体形成之后,数量丰富,多为单细胞,分布于原叶体背腹面及边缘。接种后60 d左右发育形成幼原叶体,成熟原叶体呈心脏形。接种后80 d左右开始有性器官出现,精子器的出现较颈卵器早10 d左右。颈卵器成熟后,颈部常向原叶体基部倾斜或弯曲。     

三角鳞毛蕨配子体发育的研究

采用混合土培养三角鳞毛蕨(Dryopteris subtriangularis)孢子,显微镜下观察记录其孢子萌发及配子体发育过程。结果表明：孢子深褐色,赤道面豆形,极面观椭圆形,单裂缝。播种1周左右孢子萌发,萌发类型为书带蕨型,配子体发育为三叉蕨型。播种2周左右发育为片状体。播种4周左右发育形成幼原叶体,成熟原叶体呈心脏形。原叶体边缘及腹面均可产生毛状体,数量丰富,为单细胞。播种6周左右开始有性器官出现,精子器近圆球形,由3细胞组成,成熟颈卵器颈部由4列细胞组成,3～5层细胞高。原叶体受精后1个月内即可观察到从原叶体上生成的幼胚。     

野雉尾金粉蕨配子体发育及其系统学意义

野雉尾金粉蕨为中国蕨科金粉蕨属植物,而金粉蕨属的系统位置一直存在争议。该研究用原生境腐殖土和改良克诺普氏(Knop’s)营养液对野雉尾金粉蕨的孢子进行培养,培养条件为温度25℃、光照强度2 500 lx、光照12 h/d,在光学显微镜下观察记录其孢子萌发和配子体发育过程。结果表明:野雉尾金粉蕨的孢子为黄褐色,四面体型,三裂缝,赤道面观为扇形,具周壁,外壁表面具网状纹饰。孢子培养7 d后开始萌发,孢子萌发类型为书带蕨型(Vittaria-type)。孢子萌发后,配子体原始细胞经多次横向分裂形成3~9个细胞的丝状体,丝状体细胞呈圆筒形,壁薄,侧壁向外鼓起,含有颗粒较大且数量较多的叶绿体。15 d左右发育为片状体,片状体多为匙状。25 d左右形成幼原叶体,幼原叶体不对称,配子体发育类型为水蕨型(Ceratopteris-type)。在原叶体发育过程中分枝丝状体非常发达,配子体呈丛状生长,整个发育过程没有毛状体产生。野雉尾金粉蕨的假根为单细胞管状,偶有分支,内无叶绿体。45 d左右精子器开始出现,精子器顶面观近圆形,侧面观为近椭圆形或短柱状。精子器成熟时,盖细胞裂开,精子逸出。60 d左右颈卵器出现,颈卵器比较大,基部略大于顶部,侧面观呈烟囱状,顶面观为铜钱状,颈部由四列细胞构成。90 d左右发育出肉眼可见的幼孢子体。从研究结果看,其配子体发育的特征与凤尾蕨科(Pteridaceae)凤尾蕨属(Pteris L.)相似,支持金粉蕨属归于凤尾蕨科的观点。该研究结果为野雉尾金粉蕨系统学研究提供了配子体发育方面的证据。     

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.