中国鹅掌楸小孢子发生的细胞化学研究

多糖、脂类和蛋白质的消长变化与花粉发育过程中营养供应存在着密切的关系。雄蕊特别是花药壁内的多糖在减数分裂过程中逐渐消耗殆尽。初期的小孢子母细胞内脂滴的含量丰富,无淀粉粒,也无颗粒状的蛋白质。进行减数分裂的小孢子母细胞内、中层及绒毡层细胞积累了大量的蛋白质与脂类;减数分裂完成后,绒毡层和四分体小孢子开始逐渐积累淀粉与脂类,但蛋白质的含量较少,至小孢子时期,小孢子壁及绒毡层细胞的径切向壁和内切向壁沉积了大量的脂类物质,而且小孢子核周围分布大量淀粉粒,未观察到蛋白质颗粒。     

中国鹅掌楸子小孢子发生的细胞化学研究

多糖,脂类和蛋白质的消长变化与花粉发育过程中营养供应存在着密切的关系。雄蕊特别是花药壁内的多糖在减数分裂过程中逐渐消耗殆尽。初期的小孢子母细胞内脂滴的含量丰富,无淀粉粒,也无颗粒状的蛋白质。进行减数分裂的小孢子母细胞内,中层及绒毡层细胞积累了大量的蛋白质与脂类;减数分裂完成后,绒毡层和四分体小孢子开始逐渐积累淀粉与脂类,但蛋白质的含量较少,至小孢子时期小孢子壁及绒毡层细胞的径向向壁和内切向壁沉积了     

白菜细胞核雄性不育花药的细胞化学观察

对一种由一对隐性基因控制的白菜细胞核雄性不育和可育株的花药进行了细胞学和组织化学研究。种子播种后,有1/4植株为不育株,其余的为可育株。通过对不育株和可育株花药发育的细胞学观察,确认不育花粉的败育发生在小孢子发育时期。用组织化学的方法研究了可育株和不育株花药发育过程中的多糖和脂类的分布动态,发现在减数分裂前,可育花药和不育花药的药隔细胞中都储藏了大量的淀粉粒。二者的差异仅是不育花药的绒毡层细胞液泡化明显。在减数分裂后的小孢子发育时期,可育花药的绒毡层细胞具有将药隔细胞中的淀粉粒多糖吸收并转化成脂类的功能,小孢子及以后的二胞花粉中也积累了大量的脂类储藏物质在不育花药中,虽然减数分裂后药隔细胞中的淀粉粒也都消失,但绒毡层细胞中的脂类物质相比很少,同时绒毡层细胞显示了明显的多糖反应,表明不育花药的绒毡层细胞将糖类转化为脂类的功能受阻。在小孢子的表面有些脂类物质,但在细胞质中却没有脂类积累。这一结果暗示在该种白菜细胞核雄性不育株中,由于花药绒毡层细胞转换多糖为脂类的功能失常,导致了小孢子的败育。     

白菜细胞核雄性不育花药的细胞化学观察

对一种由一对隐性基因控制的白菜细胞核雄性不育和可育株的花药进行了细胞学和组织化学研究。种子播种后,有1／4植株为不育株,其余的为可育株。通过对不育株和可育株花药发育的细胞学观察,确认不育花粉的败育发生在小孢子发育时期。用组织化学的方法研究了可育株和不育株花药发育过程中的多糖和脂类的分布动态,发现在减数分裂前,可育花药和不育花药的药隔细胞中都储藏了大量的淀粉粒。二者的差异仅是不育花药的绒毡层细胞液泡化明显。在减数分裂后的小孢子发育时期,可育花药的绒毡层细胞具有将药隔细胞中的淀粉粒多糖吸收并转化成脂类的功能,小孢子及以后的二胞花粉中也积累了大量的脂类储藏物质。在不育花药中,虽然减数分裂后药隔细胞中的淀粉粒也都消失,但绒毡层细胞中的脂类物质相比很少,同时绒毡层细胞显示了明显的多糖反应,表明不育花药的绒毡层细胞将糖类转化为脂类的功能受阻。在小孢子的表面有些脂类物质,但在细胞质中却没有脂类积累。这一结果暗示在该种白菜细胞核雄性不育株中,由于花药绒毡层细胞转换多糖为脂类的功能失常,导致了小孢子的败育。     

巴戟天花药发育过程中多糖和脂滴分布特征

巴戟天花药发育中多糖和脂滴类物质的分布呈现一定的规律：减数分裂之前,花药壁的绒毡层细胞中有少量脂滴,其他细胞中脂滴和淀粉粒都很少。四分体时期,四分体小孢子中开始出现脂滴,绒毡层细胞中的脂滴较以前增加,其他细胞中的脂滴和淀粉粒仍然很少。小孢子早期,游离小孢子在其表面形成了花粉外壁,靠外壁下方有一层周缘分布的多糖物质。绒毡层细胞中的脂滴明显减少。发育晚期的小孢子中形成一个大液泡,细胞质中出现淀粉粒;同时在药壁和药隔组织中也出现了淀粉粒。此时绒毡层退化。在二胞花粉早期,花粉中积累了大量淀粉粒和一些脂滴。但在成熟的花粉中（二胞花粉晚期）,淀粉粒消失,只有一定数量的脂滴保留。巴戟天成熟花粉中积累的营养物质主要为脂滴。     

辣椒细胞质雄性不育花药败育及淀粉粒分布的细胞学观察

用PAS反应对辣椒细胞质雄性不育系8214A和保持系8214B花药中的淀粉粒分布进行研究.在减数分裂前,保持系花药与不育系花药的结构和淀粉粒分布相似.保持系花药减数分裂后,药壁绒毡层细胞开始液泡化并体积增大,在药隔薄壁细胞中积累了许多较小的淀粉粒;在小孢子晚期,绒毡层细胞退化,在药隔薄壁细胞中淀粉粒体积增大;在二胞花粉时期,随着花粉大液泡的消失花粉中出现淀粉粒;花粉成熟时,其细胞质中积累了丰富的淀粉粒.不育系花药减数分裂后,由于药室腔的空间不能扩大,四分体被挤压在一起,最终四分体小孢子败育.不育花药的维管组织发育正常,但较多的淀粉粒积累在药隔薄壁细胞中.该种辣椒雄性不育系中.花粉的败育发生在四分体时期.绒毡层细胞结构异常可能影响糖类物质向药室的正常转运.该种辣椒雄性不育系的绒毡层异常与花粉败育有关.     

蓝猪耳花药发育中多糖和脂滴的组织化学研究

对蓝猪耳花药发育中营养物质的分布和转化过程进行组织化学研究,结果表明:在造孢细胞时期,药壁细胞没有营养物质的积累,但在造孢细胞中有少量的脂滴;在小孢子母细胞时期,表皮细胞中出现淀粉粒,而在绒毡层细胞中出现脂滴,小孢子母细胞中也有脂滴的分布;在四分体时期,四分体小孢子中出现淀粉粒,绒毡层细胞脂滴增加;在小孢子早期,药室内壁细胞中出现淀粉粒,绒毡层继续积累脂滴,而小孢子中开始出现脂滴;到小孢子晚期,绒毡层细胞降解,细胞残留物中出现较多脂滴;在二胞花粉早期,花粉中的大液泡消失,花粉开始积累淀粉粒;在即将开花的成熟花粉中则积累了大量的脂滴和少量的淀粉粒.蓝猪耳花药发育中多糖和脂滴两种营养物质的积累和分布具有一定的时、空特点,反映出花药发育中营养物质积累的规律.     

扁豆绒毡层发育的超微结构研究

应用透射电镜对扁豆绒毡层发育过程进行了研究,主要结果如下：１）首次发现扁豆绒毡层在发育过程中,经历了二交胞质重组（第一次始于减数分裂末期Ⅱ,第二次始于小孢子发育早期）,使绒毡层细胞的活动呈现３个高峰期（即小孢子母细胞减数分裂期、小孢子四分体期一小孢子早期、小孢子晚期－二胞花粉中期）。２绒毡层细胞的分泌作用有３种形式（渗透分泌、胞吐分泌和自溶）。３．首次观察到绒毡层细胞的内切向壁和径向壁经历了两个周     

同源四倍体水稻小孢子发生的超微结构

利用透射电子显微镜对同源四倍体水稻小孢子母细胞减数分裂前及期间的超微结构进行观察,结果发现:(1)减数分裂前及减数分裂早期,小孢子母细胞核糖体密度高,线粒体、质体等细胞器丰富;粗线期核糖体密度显著下降,线粒体、质体等细胞器数量减少;终变期核糖体密度逐渐恢复到减数分裂前状态,而其他细胞器的数量除在二分体时期出现短暂的回升,终变期以后的时期均较少.(2)小孢子母细胞间的连接在小孢子母细胞时期以典型的胞间连丝为主,进入细线期,胞间连丝数量显著减少,宽孔道的胞质通道逐渐增多,粗线期小孢子母细胞间基本通过胞质通道连接,终变期小孢子母细胞间完全分离.(3)随着减数分裂的进行,药壁四层细胞逐渐液泡化,绒毡层细胞中部分小液泡融合成大液泡,形成胞内"空腔";药室内壁细胞出现大量的具有叶绿体结构特征的质体,内含丰富的淀粉粒,到了四分体时期质体数量及内含的淀粉粒显著减少.     

胡萝卜花药发育的组织化学研究

胡萝卜四分体时期的花药在药室内壁和绒毡层细胞中积累淀粉粒,随着花药的发育,花粉先出现大液泡,同时药室内壁和绒毡层细胞中淀粉粒消失;以后花粉中的大液泡消失,在花粉细胞质中出现淀粉粒。伴随着花粉的发育,绒毡层细胞退化,在细胞中积累较多的脂类物质,同时花粉中脂类物质含量也明显增加。胡萝卜成熟花粉粒的储存物主要为脂滴,也有少部分淀粉颗粒。胡萝卜花药在特定时间和特定部位积累营养储存物的过程也是其发育的一个特征。     

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.