GTPase Activity of MxB Contributes to Its Nuclear Location,Interaction with Nucleoporins and Anti-HIV-1 Activity

The human myxovirus resistance 2(Mx2/Mx B) protein, a member of interferon(IFN)-inducible dynamin-like large GTPases, restricts a number of virus infections. Inhibition of these viruses occurs at poorly-defined steps after viral entry and has a common requirement for Mx B oligomerization. However, the GTPase activity is essential for the anti-viral effects of Mx B against herpesviruses and HBV but not HIV-1. To understand the role of Mx B GTPase activity, including GTP binding and GTP hydrolysis, in restriction of HIV-1 infection, we genetically separated these two functions and evaluated their contributions to restriction. We found that both the GTP binding and hydrolysis function of Mx B involved in the restriction of HIV-1 replication. The GTPase activity of Mx B contributed to its nuclear location, interaction with nucleoporins(NUPs) and HIV-1 capsids. Furthermore, Mx B disrupted the association between NUPs and HIV-1 cores dependently upon its GTPase activity. The function of GTPase activity was therefore multi-faceted, led to fundamentally distinct mechanisms employed by wild-type Mx B and GTPase activity defective Mx B mutations to restrict HIV-1 replication.     

Study of cell killing and morphology on S180 by ultrasound activating hematoporphyrin derivatives

The inhibition of ascitic S180 and induced sarcoma 180 in vivo was studied with the combination of hematoporphyrin derivatives (HpD) and ultrasound (US) at the frequency of 1.1 MHz and different intensities by light microscopy observation, electronic microscopy observation, cytochemical analysis and fluorescence labeling. The present study indicated that the injury of ascitic S180 increased as time passed and the inhibitory effect was stronger in US plus HpD group than that in other groups. Our results also indicated that the changes in cell structure, cytochrome C oxidase activity, the degradation and missing of DNA were the important factors that inhibited the tumor cell growth and even induced celldeath. The phenomenon of apoptosis of tumor cells indicated that cell death andinduced apoptosis exist in the treatment of sonodynamic therapy (SDT). Our study investigated the mechanism underlying the killing effect of S180 induced by USactivating HpD by the observation of cell morphology and dynamic changes from seminal injury to succeeded injury even to death. It would provide rich referencefor the study of SDT.     

利用锌特异性探针HL~1示踪植物细胞外Zn~(2+)的分布

以拟南芥(Arabidopsis thaliana)和谷子(Setaria italic)为研究材料,利用锌特异性探针HL1,使用荧光分光光度仪、等温滴定热量测定仪(ITC200)和倒置荧光显微镜等仪器探究了该化学探针的特性以及植物细胞外游离Zn~(2+)的分布。结果表明,当HL1与不同元素溶液混合时,只与Zn~(2+)特异性结合,在紫外光(UV)激发下,发射出波长为500 nm的蓝色荧光;生成物的平衡解离常数KD=7.02×10–4 mol·L–1,具有很好的稳定性。拟南芥叶片中的Zn~(2+)分布于细胞间隙及叶表皮毛的外周和表层,且叶表皮毛的荧光强度具有明显的浓度依赖性;谷子叶片中的Zn~(2+)分布在细胞间隙以及维管组织。拟南芥根中的Zn~(2+)分布于根的伸长区,且荧光强度也明显地表现出与浓度相关。由此推断,根伸长区与Zn~(2+)运输有关,叶的维管组织是植物细胞外运输Zn~(2+)的主要途径,细胞间隙和叶表皮毛是植物储存Zn~(2+)的主要区域。HL1适用于检测细胞外Zn~(2+)的分布。     

Dynamic responses of picophytoplankton to physicochemical variation in the eastern Indian Ocean

Picophytoplankton were investigated during spring 2015 and 2016 extending from near‐shore coastal waters to oligotrophic open waters in the eastern Indian Ocean (EIO). They were typically composed of Prochlorococcus (Pro), Synechococcus (Syn), and picoeukaryotes (PEuks). Pro dominated most regions of the entire EIO and were approximately 1–2 orders of magnitude more abundant than Syn and PEuks. Under the influence of physicochemical conditions induced by annual variations of circulations and water masses, no coherent abundance and horizontal distributions of picophytoplankton were observed between spring 2015 and 2016. Although previous studies reported the limited effects of nutrients and heavy metals around coastal waters or upwelling zones could constrain Pro growth, Pro abundance showed strong positive correlation with nutrients, indicating the increase in nutrient availability particularly in the oligotrophic EIO could appreciably elevate their abundance. The exceptional appearance of picophytoplankton with high abundance along the equator appeared to be associated with the advection processes supported by the Wyrtki jets. For vertical patterns of picophytoplankton, a simple conceptual model was built based upon physicochemical parameters. However, Pro and PEuks simultaneously formed a subsurface maximum, while Syn generally restricted to the upper waters, significantly correlating with the combined effects of temperature, light, and nutrient availability. The average chlorophyll a concentrations (Chl a) of picophytoplankton accounted for above 49.6% and 44.9% of the total Chl a during both years, respectively, suggesting that picophytoplankton contributed a significant proportion of the phytoplankton community in the whole EIO.     

植酸对稻米品质影响的研究（Ⅰ）

本文报道在水稻生长的抽穗期、齐穗期、灌浆期和蜡熟期喷施不同浓度植酸改良稻米品质的研究。结果表明,在水稻生长的不同阶段,控制喷施植酸浓度可提高糙米率,降低稻米垩白。     

黄雀发声核团与部分听觉中枢内P物质的分布和性双态比较

用免疫组织化学方法研究P物质在雌雄黄雀发声控制核团和听觉中枢内的分布,结合计算机图像分析仪检测SP免疫阳性细胞和末梢的灰度值,并作雌雄比较。结果如下：1．在发声学习中枢嗅叶X区有大量的SP阳性神经末梢和一些神经细胞。2．在发声控制核团前脑高级发声中枢(HVc)、古纹状体栎核、发声学习中枢新纹状体巨细胞核和丘脑背内侧核外侧部内有许多的SP免疫阳性细胞。3．在发声控制中枢中脑背内侧核和延髓舌下神经核气管鸣管部、听觉中枢丘脑卵圆核的壳区、中脑背外侧核壳区及中脑丘间核等有密集的SP免疫阳性神经末梢和纤维分布;雄性发声中枢内SP的分布比雌性丰富,两者有显著的差异。结果表明：SP的分布在雌雄发声中枢之间存在显著的性双态;SP广泛分布于黄雀发声控制核团和部分听觉中枢内,提示SP可能在发声控制及听觉中枢内具有重要的生理功能。     

Evaluation of formulations of Bacillus licheniformis for the biological control of tomato gray mold caused by Botrytis cinerea

Bacillus licheniformis N1, which has previously exhibited potential as a biological control agent, was investigated to develop a biofungicide to control the gray mold of tomato caused by Botrytis cinerea. Various formulations of B. licheniformis N1 were developed using fermentation cultures of the bacteria in Biji medium, and their ability to control gray mold on tomato plants was evaluated. The results of pot experiments led to the selection of the wettable powder formulation N1E, based on corn starch and olive oil, for evaluation of the disease control activity of this bacterium after both artificial infection of the pathogen and natural disease occurrence under production conditions. In plastic-house artificial infection experiments, a 100-fold diluted N1E treatment was found to be the optimum biofungicide spray formulation. This treatment resulted in the significant reduction of symptom development when N1E was applied before Bo. cinerea infection, but not after the infection. Both artificial infection experiments in a plastic house and natural infection experiments under production conditions revealed that the N1E significantly reduced disease severity on tomato plants and flowers. The disease control value of N1E on tomato plants was 90.5% under production conditions, as compared to the 77% conferred by a chemical fungicide, the mixture of carbendazim and diethofencarb (1:1). The prevention of flower infection by N1E resulted in increased numbers of tomato fruits on each plant. N1E treatment also had growth promotion activity, which showed the increased number of tomato fruits compared to fungicide treatment and non-treated control and the increased fruit size compared the non-treated control under production conditions. This study suggests that the corn starch-based formulation of B. licheniformis developed using liquid fermentation will be an effective tool in the biological control of tomato gray mold.     

Characterization of a putative thioredoxin peroxidase prx1 of <Emphasis Type="Italic">Candida albicans</Emphasis>

In this study, we characterized a putative peroxidase Prx1 of Candida albicans by: 1) demonstrating the thioredoxin-linked peroxidase activity with purified proteins, 2) examining the sensitivity to several oxidants and the accumulation of intracellular reactive oxygen species with a null mutant (prx1Δ), a mutant (C69S) with a point mutation at Cys69, and a revertant, and 3) subcelluar localization. Enzymatic assays showed that Prx1 is a thioredoxin-linked peroxidase which reduces both hydrogen peroxide (H₂O₂) and tert-butyl hydroperoxide (t-BOOH). Compared with two other strong H₂O₂ scavenger mutants for TSA1 and CAT1, prx1Δ and C69S were less sensitive to H₂O₂, menadione and diamide at all concentrations tested, but were more sensitive to low concentration of t-BOOH. Intracellular reactive oxygen species accumulated in prx1Δ and C69S cells treated with t-BOOH but not H₂O₂. These results suggest that peroxidase activity of Prx1 is specified to t-BOOH in cells. In both biochemical and physiological cases, the evolutionarily conserved Cys69 was found to be essential for the function. Immunocytochemical staining revealed Prx1 is localized in the cytosol of yeast cells, but is translocated to the nucleus during the hyphal transition, though the significances of this observation are unclear. Our data suggest that PRX1 has a thioredoxin peroxidase activity reducing both t-BOOH and H₂O₂, but its cellular function is specified to t-BOOH.     

SRNAome and degradome sequencing analysis reveals specific regulation of sRNA in response to chilling injury in tomato fruit

Plant genomes encode diverse small RNA classes that function in distinct gene‐silencing pathways. To elucidate the intricate regulation of microRNAs (miRNAs) and endogenous small‐interfering RNAs (siRNAs) in response to chilling injury in tomato fruit, the deep sequencing and bioinformatic methods were combined to decipher the small RNAs landscape in the control and chilling‐injured groups. Except for the known miRNAs and ta‐siRNAs, 85 novel miRNAs and 5 ta‐siRNAs members belonging to 3 TAS families (TAS5, TAS9 and TAS10) were identified, 34 putative phased small RNAs and 740 cis/trans‐natural antisense small‐interfering RNAs (nat‐siRNAs) were also found in our results which enriched the tomato small RNAs repository. A large number of genes targeted by those miRNAs and siRNAs were predicted to be involved in the chilling injury responsive process and five of them were verified via degradome sequencing. Based on the above results, a regulatory model that comprehensively reveals the relationships between the small RNAs and their targets was set up. This work provides a foundation for further study of the regulation of miRNAs and siRNAs in the plant in response to chilling injury.