水肥耦合对玉米籽粒全氮含量的影响

采用四因素五水平(1/2实施)二次通用旋转组合设计,选取灌水、施氮肥、施磷肥和秸秆覆盖四因素作为试验因素,在辽西半干旱区褐土农田进行了水肥耦合效应长期定位试验。按照二次通用旋转组合设计统计分析方法建立回归模型,分析了水肥耦合对玉米籽粒全氮含量的影响。结果表明:水肥单因子对籽粒全氮的含量有较明显的影响,影响顺序为施氮秸秆覆盖施磷灌水;当灌水量为700m3.hm-2、施氮量为180kg.hm-2、施磷量为120kg.hm-2和秸秆覆盖量为7500kg.hm-2时,它们每个因素对玉米籽粒全氮含量的影响都集中11.7g·kg-1,此时籽粒蛋白质含量为73g·kg-1,产量为12000kg.hm-2,表明该处理组合下,玉米的经济效益和生态效益达到最佳,推荐生产上以此进行施肥。     

锌转运体ZNT7在Alzheimer病动物模型APP/PS1转基因鼠脑内的表达

目的研究阿尔茨海默病（Alzheimer disease,AD）模型小鼠APP/PS1转基因小鼠脑内锌转运体ZNT7的分布和表达,探讨ZNT7参与Aβ老年斑形成的机理。方法应用免疫组织化学染色观察ZNT7在脑内分布情况,应用Western Blot方法分析ZNT7在APP/PS1转基因小鼠大脑内的表达。结果ZNT7免疫阳性反应产物主要分布在APP/PS1转基因小鼠大脑皮层、纹状体和海马的老年斑内,强阳性的ZNT7免疫产物定位于老年斑的核心。Western Blot分析结果表明ZNT7在APP/PS1转基因小鼠大脑内的表达明显高于野生型小鼠。结论ZNT7在APP/PS1转基因小鼠大脑内的高表达以及在Aβ老年斑的定位,提示ZNT7可能参与了锌离子在老年斑内的聚集,进而参与了APP/PS1转基因小鼠大脑内老年斑的形成。     

OxLDL-induced macrophage cytotoxicity is mediated by lysosomal rupture and modified by intralysosomal redox-active iron

Oxidized low density lipoprotein (oxLDL) is believed to play a central role in atherogenesis. LDL is oxidized in the arterial intima by mechanisms that are still only partially understood. OxLDL is then taken up by macrophages through scavenger receptor-mediated endocytosis, which then leads to cellular damage, including apoptosis. The complex mechanisms by which oxLDL induces cell injury are mostly unknown. This study has demonstrated that oxLDL-induced damage of macrophages is associated with iron-mediated intralysosomal oxidative reactions, which cause partial lysosomal rupture and ensuing apoptosis. This series of events can be prevented by pre-exposing cells to the iron-chelator, desferrioxamine (DFO), whereas it is augmented by pretreating the cells with a low molecular weight iron complex. Since both DFO and the iron complex would be taken up by endocytosis, and thus directed to the lysosomal compartment, the results suggest that the normal contents of lysosomal low molecular weight iron may play an important role in oxLDL-induced cell damage, presumably by catalyzing intralysosomal fragmentation of lipid peroxides and the formation of toxic aldehydes and oxygen-centered radicals.     

Recovery of transgenic rice plants expressing the rice dwarf virus outer coat protein gene (S8)

 The coding region of the eighth largest segment (S8) of the rice dwarf virus (RDV) was obtained from a RDV Fujian isolate. It was then cloned into pTrcHisA for expression in E. coli and into vector pE3 for plant transformation. By using callus derived from mature rice embryos as the target tissue, we obtained regenerated rice plants after bombardment of the former with plasmid pE3R8 containing the RDV S8 gene and the marker gene neomycin phosphotransferase (NPT II). Southern blotting confirmed the integration of the RDV S8 gene into the rice genome. The expression of the outer coat protein in both E. coli and rice plants was confirmed by western blotting. The recovery of transgenic rice plants expressing S8 gene is an important step towards studying the function of the RDV genes and obtaining RDV-resistant rice plants. Received: 1 March 1996 / Accepted: 2 August 1996     

Molecular mapping of a major gene conferring resistance to maize mosaic virus

 The objective of this study was to determine the genetic basis of resistance to maize mosaic virus (MMV). Molecular markers were used to map resistance loci to MMV in a set of 91 maize (Zea mays L.) recombinant inbred lines (RILs), derived from the cross between Hi31 (a B68 conversion resistant to MMV) and Kil4 (a Thai inbred susceptible to MMV). The RILs were evaluated for MMV resistance in disease nurseries in Hawaii in the winter of 1993 and the summer of 1994. Twenty-eight highly susceptible RILs were chosen for gene mapping using the pooled-sampling approach. Initial evidence from the pooled DNA indicated that restriction fragment length polymorphism (RFLP) probes on chromosome 3 near the centromere were biased to the susceptible parent allele. Analysis of 91 RILs at 103 RFLP loci confirmed the presence of a major MMV resistance gene on chromosome 3. The resistant allele at this locus, previously named Mv1, is present in the resistant parent Hi31 and traces back to the Argentine parent used in conferring common rust resistance to B68. We conclude that resistance to MMV in B68 and Caribbean flints involves a major gene mv1 on chromosome 3 located between RFLP markers umc102 and php20508. Received: 12 June 1996 / Accepted: 5 July 1996     

用人工合成的丁型肝炎病毒抗原多肽检测丁肝病毒IgM抗体及其初步应用

用人工合成的丁型肝炎病毒抗原（ＨＤＶ－Ａｇ）肽建立了检测抗ＨＤＶ－ＩｇＭ抗体的ＥＬＩＳＡ方法,本法操作简便、快速,重复性好,特异性强,与抗ＨＡＶ－ＩｇＭ、抗Ｈｋ－ＩｇＭ、抗ＨＢｓ－ＩｇＭ、抗ＨＣＶ－ＩｇＩ、抗ＣＭＶ－ＩｇＭ、抗ＲＶ－ＩｇＭ、类风湿因子（ＲＦ）及抗核抗体（ＡＮＡ）阳性血清均不起反应,且可被２－巯基乙醇阻断而不起反应。经初步临床应用,３１例正常人血清抗ＨＤＶ－ＩｇＭ全部阴性,２８例慢活肝患者检出率为３２．１％（９／２８）,１７例慢迁肝患者血清阳性率为１１．８％（２／１７）１８例肝癌和肝硬化病人血清阳性率为２２．２％（４／１８）这三组病人与正常对照者相比较均有显著性差异（Ｐ＜０．００１）。此外,抗ＨＤＶ－ＩｇＭ阳性血清的ＡＬＴ值均明显高于正常参考范围,提示在ＨＤＶ感染过程中,患者肝细胞进一步受损。实验结果证明,抗ＨＤＶ－ＩｇＭ是诊断ＨＤＶ感染的重要指标,对ＨＤＶ感染早期诊断具有重要价值。     

Specific cancer stem cell-therapy by albumin nanoparticles functionalized with CD44-mediated targeting

Background

Cancer stem cells (CSCs) are highly proliferative and tumorigenic, which contributes to chemotherapy resistance and tumor occurrence. CSCs specific therapy may achieve excellent therapeutic effects, especially to the drug-resistant tumors.

Results

In this study, we developed a kind of targeting nanoparticle system based on cationic albumin functionalized with hyaluronic acid (HA) to target the CD44 overexpressed CSCs. All-trans-retinoic acid (ATRA) was encapsulated in the nanoparticles with ultrahigh encapsulation efficiency (EE%) of 93% and loading content of 8.37%. TEM analysis showed the nanoparticles were spherical, uniform-sized and surrounded by a coating layer consists of HA. Four weeks of continuously measurements of size, PDI and EE% revealed the high stability of nanoparticles. Thanks to HA conjugation on the surface, the resultant nanoparticles (HA-eNPs) demonstrated high affinity and specific binding to CD44-enriched B16F10 cells. In vivo imaging revealed that HA-eNPs can targeted accumulate in tumor-bearing lung of mouse. The cytotoxicity tests illustrated that ATRA-laden HA-eNPs possessed better killing ability to B16F10 cells than free drug or normal nanoparticles in the same dose, indicating its good targeting property. Moreover, HA-eNPs/ATRA treatment decreased side population of B16F10 cells significantly in vitro. Finally, tumor growth was significantly inhibited by HA-eNPs/ATRA in lung metastasis tumor mice.

Conclusions

These results demonstrate that the HA functionalized albumin nanoparticles is an efficient system for targeted delivery of antitumor drugs to eliminate the CSCs.

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极端晚播对小麦籽粒产量、氮素吸收利用和籽粒蛋白质含量的影响

为探索小麦高产高效优质生产技术途径,指导小麦晚播生产实践,2012年10月—2014年6月,以弱春性小麦偃展4110和半冬性小麦矮抗58为材料进行连续2年的田间定位试验,设置了常规适播(10月中旬、240万株·hm^-2)和极端晚播(11月中旬、600万株·hm^-2)两种栽培模式,研究了极端晚播对0～40 cm土层土壤硝态氮含量、小麦氮素吸收利用、产量、籽粒蛋白质含量和氮素吸收效率的影响.结果表明: 与常规适播处理相比,两个生长季极端晚播处理均使拔节和开花期0～40 cm土壤硝态氮含量显著提高,从而促进拔节后小麦植株氮素吸收积累,成熟期穗部氮素的分配比例也得到提高,最终显著提高小麦籽粒蛋白质含量和偃展4110的蛋白质产量、氮素吸收效率,但对籽粒产量的影响因品种而异.其中,极端晚播处理使偃展4110的籽粒产量显著提高,而矮抗58的籽粒产量却显著降低.因此,极端晚播栽培模式可维持小麦拔节后的土壤氮供应,有利于提高小麦氮素吸收效率,从而提高小麦籽粒产量和蛋白质含量,是灌区小麦高产优质的有效途径之一.     

不同生境下荒漠植物红砂-珍珠猪毛菜混生根系的垂直分布规律

植物种间相互作用及其对环境胁迫的响应一直是物种共存和生物多样性维持研究的一个热点, 从地下根系入手来探讨混生群落植物种间关系及其对环境胁迫响应的研究少见报道。该文以荒漠草原区(灵武)、典型荒漠区(张掖)和极端荒漠区(酒泉) 3个不同生境条件下单生与混生红砂(Reaumuria soongarica)和珍珠猪毛菜(Salsola passerina)为实验材料, 采用分层取样法对其垂直根系参数进行测定和分析, 探讨了两种植物根系分布对混生及荒漠环境梯度的响应。结果表明: 同一生境条件下, 混生红砂和珍珠猪毛菜比根长和比表面积均高于单生, 说明红砂、珍珠猪毛菜混生后其根系相互作用关系表现为互惠, 促进了植株对土壤养分和水分的吸收。不同生境条件下, 同一生长方式的红砂根系分布深度均大于珍珠猪毛菜, 且根系消弱系数也普遍高于珍珠猪毛菜, 说明二者在不同生境条件下占据不同生态位, 红砂表现为深根性, 根系位于土壤深层, 珍珠猪毛菜表现为浅根性, 根系分布于土壤浅层。随着荒漠环境胁迫增强, 单生和混生红砂与珍珠猪毛菜的比根长和比表面积均呈现出极端荒漠区>典型荒漠区>草原荒漠区的规律, 且生境越干旱, 混生群落根系分离越明显; 单生与混生红砂根系消弱系数也逐渐增大, 在极端干旱区达到最大值, 珍珠猪毛菜变化不大, 表明红砂-珍珠猪毛菜混生群落根系生态位分离随荒漠环境胁迫增强而加大, 验证了环境胁迫梯度假说。可见“地上聚生, 地下分离”的混生方式可能是红砂-珍珠猪毛菜混生群落适应干旱胁迫环境的生长策略。     

Sphingosine‐1‐phosphate (S1P) enhances glomerular endothelial cells activation mediated by anti‐myeloperoxidase antibody‐positive IgG

Cumulating evidences suggested an important role of sphingosine‐1‐phosphate (S1P) and its receptors in regulating endothelial barrier integrity. Our previous study revealed that the circulating S1P levels and renal expression of S1PRs correlated with disease activity and renal damage in patients with antineutrophil cytoplasmic antibody (ANCA)‐associated vasculitis (AAV). This study investigated the role of S1P and its receptors in myeloperoxidase (MPO)‐ANCA‐positive IgG‐mediated glomerular endothelial cell (GEnC) activation. The effect of S1P on morphological alteration of GEnCs in the presence of MPO‐ANCA‐positive IgG was observed. Permeability assay was performed to determine endothelial monolayer activation in quantity. Both membrane‐bound and soluble ICAM‐1 and VCAM‐1 levels were measured. Furthermore, antagonists and/or agonists of various S1PRs were employed to determine the role of different S1PRs. S1P enhanced MPO‐ANCA‐positive IgG‐induced disruption of tight junction and disorganization of cytoskeleton in GEnCs. S1P induced further increase in monolayer permeability of GEnC monolayers in the presence of MPO‐ANCA‐positive IgG. S1P enhanced MPO‐ANCA‐positive IgG‐induced membrane‐bound and soluble ICAM‐1/VCAM‐1 up‐regulation of GEnCs. Soluble ICAM‐1 levels in the supernatants of GEnCs stimulated by S1P and MPO‐ANCA‐positive IgG increased upon pre‐incubation of S1PR1 antagonist, while pre‐incubation of GEnCs with the S1PR1 agonist down‐regulated sICAM‐1 level. Blocking S1PR2‐4 reduced sICAM‐1 levels in the supernatants of GEnCs stimulated by S1P and MPO‐ANCA‐positive IgG. Pre‐incubation with S1PR5 agonist could increase sICAM‐1 level in the supernatants of GEnC stimulated by S1P and MPO‐ANCA‐positive IgG. S1P can enhance MPO‐ANCA‐positive IgG‐mediated GEnC activation through S1PR2‐5.