内源脱落酸和赤霉素对番茄发育果实和种子水分关系的影响

利用热偶湿度计（ｔｈｅｒｍｏｃｏｕｐｌｅｐｓｙｃｈｒｏｍｅｔｅｒ）研究了野生型、ＧＡ－缺陷型和ＡＢＡ－缺陷型番茄发育过程中果实种子的水分关系,发现除ＡＢＡ－缺陷型种子胶囊和果肉水势变化特殊外,３种类型果实水分状况变化基本一致;在整个发育时期内．前期种子胶囊和果肉水分流向种子,中期种子水分流向种子胶囊和果肉,后期种子和果实间的水势达到平衡。鉴于种胚脱水是一种主动过程,种胚水势一直低于整个种子、种子胶囊和果肉。内源赤霉素可明显增加果实和种子的重量,但对增加种胚溶质的作用不大。由于内源脱落酸可以促使果实成熟和衰老,促进果实细胞解体,大大降低种子胶囊和果肉水势,因而抑制成熟种子在果实内萌发。     

内源脱落酸和赤霉素对番茄发育果实和种子水分关系的影响

利用热偶湿度计研究了野生型、ＧＡ－缺陷型和ＡＢＡ－缺陷型番茄发育过程中果实种子的水分关系,发现除ＡＢＡ－缺陷型种子胶囊和果肉水势变化特殊外,３种类型果实水分状况变化基本一致;在整个发育时期内,前期种子胶囊和果肉水分流向种子,中期种子水分流向种子胶囊和果肉,后期种子和果实间的水势达到平衡。鉴于种胚脱水是一种主动过程,种胚水势一直低于整个种子、种子胶囊和果肉。内源赤霉素可明显增加果实和种子的重量,但对     

赤霉素与脱落酸对番茄种子萌发中细胞周期的调控

利用细胞流检仪检测番茄（Ｌｙｃｏｐｅｒｓｉｃｏｎ ｅｓｃｕｌｅｎｔｕｍ Ｍｉｌｌ．） ＧＡ－缺陷型、ＡＢＡ－缺陷型和相应的正常品种（野生型）成熟种子胚根尖细胞倍性水平时发现：ＧＡ－缺陷型和野生型种子绝大多数细胞ＤＮＡ 水平为２Ｃ,而ＡＢＡ－缺陷型种子则含有较多的４Ｃ细胞。在标准发芽条件下,ＡＢＡ－缺陷型和野生型种子浸种１ ｄ 后胚根尖细胞ＤＮＡ 开始复制,随后胚根突破种皮而发芽。然而ＧＡ－缺陷型种子除非加入外源ＧＡ,否则既不发生细胞ＤＮＡ 复制,也不发芽。这说明内源ＧＡ 是启动番茄种子胚根尖细胞ＤＮＡ 复制的关键因素,同时也说明番茄根尖细胞ＤＮＡ 复制是种子发芽的必要条件。实验证明：ＡＢＡ 不抑制细胞ＤＮＡ 合成,但阻止Ｇ２ 细胞进入到Ｍ 期。外源ＡＢＡ处理野生型种子与渗控处理结果相似,可以大幅度提高胚根尖４Ｃ／２Ｃ细胞的比例,但抑制种子的最终发芽     

矮生鸡冠花的离体快繁及试管苗开花

１植物名称矮生鸡冠花（Ｃｅｌｏｓｉａｃｒｉｓｔａｔａ）。２材料名称无菌种子苗顶芽、腋芽。３培养条件基本培养基为ＭＳ。培养基组合为：（１）ＭＳ＋ＢＡ１－２ｍｇ·Ｌ~（－１）（单位下同）＋ＮＡＡ０．１～０．２;（２）ＭＳ＋ＢＡ２＋ＩＡＡ０．２;（３）ＭＳ＋ＫＴ２;（４）ＭＳ＋ＢＡ０．１～０．５。以上培养基均含３％蔗糖,０．６％琼脂,ｐＨ为５．８,培养温室为（２６±２）℃,光照１２ｈ．ｄ~（－１）（２０００ｌｘ）。４生长与分化情况４．１无菌材料的获得成熟的种子置７０％酒精中摇动５０ｓ后,转入饱和漂白粉溶…     

南川升麻种子休眠与萌发的研究

南川升麻（ＣｉｍｉｃｉｆｕｇａｎａｎｃｈｕａｎｅｎｓｉｓＨｓｉａｏ）的种子自然脱落时尚处于球形胚发育阶段,需要长时间的越冬过程才能完成胚的后熟。室内采用低温湿润或不同浓度的ＧＡ３处理,可以不同程度地加快其胚的后熟过程。休眠种子用０．１ｇ／ＬＧＡ３处理１周后,在低温（１～５℃）湿润条件下存放约９０ｄ,萌发率可达到７０％以上。     

枇杷种子的脱水敏感性与膜脂过氧化作用

枇杷种子不耐贮藏,属于脱水敏感的种子。在干燥脱水过程中,子叶和胚轴的超氧物歧化酶（ＳＯＤ） 和过氧化物酶（ＰＯＤ） 活性不断下降,而丙二醛（ ＭＤＡ） 含量及种子浸泡液的电导率不断增加,种子活力逐渐降低。外源０ ．０５ ～０ ．２５ ｍｍｏｌ／Ｌ 的抗坏血酸（ＡＳＡ） ,０ ．０５ ～５ ．０ ｍｍｏｌ／Ｌ 的还原性谷胱甘肽（ＧＳＨ）和０ ．０５ ～０ ．５ ｍｍｏｌ／Ｌ 的Ｃａ２ ＋ 处理能有效地增强种胚防御过氧化的能力,缓解氧自由基对种胚的伤害,提高脱水劣变的种子活力。     

油松体细胞无性系的建立

以油松（Ｐｉｎｕｓｔａｂｕｌａｅｆｏｒｍｉｓ）种胚为外植体,通过器官发生途径建立体细胞无性系。以ＭＳ为基本培养基,在芽的诱导和增殖培养基中,附加植物激素,以６ＢＡ＋ＫＴ和ＮＡＡ效果最好,两者的配比为５－１０：１,６ＢＡ和ＫＴ的浓度分别均不超过１ｍｇ／Ｌ。同时根据培养物的发育状态交替使用活性炭,则对芽的增殖有明显的促进作用。选择发育状态较幼嫩的刚抽茎的外植体,诱导生根,在１／２ＭＳ＋ＫＴ０．１＋ＩＢＡ０．１＋ＮＡＡ０．１ｍｇ／Ｌ的培养基中,生根率达３２．％。体细胞胚胎发生途径建立细胞无性系也已取得成功,筛选出可继代培养的胚性胚柄团无性系,在胚轴和子叶上诱导出成熟的体细胞胚并获得完整小植株。     

海边香豌豆胚性愈伤组织的诱导和体细胞胚发生

将生长１４ｄ的海边香豌豆（Ｌａｔｈｙｒｕｓ ｍａｒｉｔｉｍｕｓ（Ｌ．）Ｂｉｇｅｌ）无菌苗下胚轴切成０．５ｃｍ左右的片段,置于含有１ｍｇ／Ｌ２,４－Ｄ,０．５ｍｇ／Ｌ ＢＡ和０．５％ＮａＣｌ的ＭＳ培养基中,２８ｄ后诱导出胚性愈伤组织。将其转入含有适当浓度２,４－Ｄ的ＭＳ培养基上,又２８ｄ后可得到大量球形胚和心形胚以及极少量鱼雷胚和子叶胚。诱导体细胞胚适合的２,４－Ｄ浓度为０．５ｍｇ／Ｌ。较高浓度的２     

第二信使介导模拟低氧下丘脑CRF分泌

用模拟高原低氧的方法研究急性低氧条件下促肾上腺皮质激素释放因子（ｃｏｒｔｉｃｏｔｒｏｐｉｎ－ｒｅｌｅａｓｉｎｇｆａｃｔｏｒ,ＣＲＦ）分泌的变化及第二信使参与ＣＲＦ分泌的作用。低氧（海拔７ｋｍ）１ｈ后,正中隆起（ｍｅｄｉａｎｅｍｉｎｅｎｃｅ,ＭＥ）处ＣＲＦ含量明显下降（Ｐ＜０．０５）,下丘脑（ｈｙｐｏｔｈａｌａｍｕｓ,Ｈｙ）ＣＲＦ（不含ＭＥ）含量无明显变化,而Ｈｙ内ｃＡＭＰ含量明显增加（Ｐ＜０．０１）。脑室注射Ｆｏｒｓｋｌｉｎ、ＴＰＡ后低氧暴露（海拔５ｋｍ）１ｈ,ＭＥＣＲＦ含量下降（Ｐ＜０．０５;Ｐ＜０．０５）,ＨｙＣＲＦ无明显变化。脑室注射Ｆｏｒｓｋｌｉｎ后ＨｙｃＡＭＰ含量升高（Ｐ＜０．０５）。脑室注射Ｈ７和ＰＫＡ抑制剂,ＭＥＣＲＦ升高（Ｐ＜０．０５;Ｐ＜０．０１）,ＨｙＣＲＦ和ＨｙｃＡＭＰ均无显著变化。上述结果表明急性低氧应激中ＣＲＦ分泌显著增加,第二信使通路ＰＫＡ和ＰＫＣ通路均参与ＣＲＦ分泌     

预浸和发芽过程中番茄种子细胞核的倍性变化

用细胞流检仪（ｆｌｏｗｃｙｔｏｍｅｔｅｒ）检测番茄种子细胞核倍性水平时发现：当年成熟的番茄种子胚细胞核ＤＮＡ绝大多数为２Ｃ水平,胚乳细胞核则为３Ｃ水平,说明成熟番茄种子细胞一般休止停留在Ｇ１期。同时我们也发现极少量的胚和胚乳细胞核分别为４Ｃ和６Ｃ水平,说明这些细胞已经进行了ＤＮＡ内复制。供试番茄种子浸种后１２ｈ左右完成吸水过程,２ｄ后胚根可突破种皮发芽。随着种子吸水过程的完成,胚根尖部分细胞开始进入ＤＮＡ复制期（Ｓ期）,而且此类细胞的数量增加迅速,一直到种子发芽。番茄胚根尖细胞进入４Ｃ的数量的多少与种子萌发时期有明显相关,４Ｃ／２Ｃ比率越大说明越接近发芽。渗控处理可以增加番茄种子胚根细胞４Ｃ／２Ｃ比率,因而明显提高种子的发芽速率。结果还表明;渗控处理的番茄种子再度干燥后４Ｃ／２Ｃ比率不变,这说明干燥可以固定细胞周期。     

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.