Regulation of fibronectin and laminin binding activity in cultured human lymphoblastic cell lines

The current study shows that a clonal derivative of the Jurkat cell line up-regulates both the avidity and density of the α 6/β1 receptor in response to phorbol 12-myristate 13-acetate (PMA). This derivative attaches to fibronectin and, to a lesser degree, laminin constitutively. Adhesion and spreading are dramatically up-regulated following treatment with PMA. The response on fibronectin peaks within 4 hours, is insensitive to cyclohexaminde, can be blocked by monoclonal antibodies (Mabs) to the β1 and α 5 subunits of the β1 family of integrins, and is not associated with increased expression of the α 5 or β1 epitopes at the cell surface. In contrast, the response on laminin is biphasic. The early phase parallels the response on fibronectin. The second phase peaks after 48–72 hours of treatment with PMA, is sensitive to cycloheximide, can be blocked by Mabs to the β1 and α 6 subunits, and is associated with increased expression of the α 6 epitope. Both the density independent and dependent responses to PMA in Jurkat cells are blocked by the protein kinase inhibitor staurosporine. The HSB-2, CEM, Molt-4, and HPB-ALL T-lymphoblastic cell lines also up-regulate attachment to fibronectin and laminin following treatment with PMA. All four lines constitutively attach to fibronectin and show rapid up-regulation of attachment following treatment with PMA. None of the lines attach to laminin prior to PMA treatment; however, specific adhesion developed after 4–120 hours of treatment. The most mature lines (Jurkat and HPB-ALL) up-regulated adhesion on laminin more rapidly than the less phenotypically mature lines (CEM, Molt-4, and HSB-2). In summary, clonal derivatives of the Jurkat cell line up-regulated attachment to laminin through protein kinase dependent increases in α /β1 receptor avidity and density. In addition, the expression of functional receptors for laminin is linked to developmental maturity in a series of T-lymphoblastic cell lines. © 1993 Wiley-Liss, Inc.     

脂肪酶水解植物油的研究

本文报导了薄层层析法及高压液相色谱法定性定量地测定植物油甘油酯的组成,对不同来源的脂肪酶对植物油的水解进行了研究。实验结果表明,不同来源的脂肪酶对植物油(橄榄油)的水解性不同,同一脂肪酶水解不同种类的植物油,脂肪酶的水解率也不同,脂肪酶水解植物油有最适pH和最适温度。     

Asymmetric effects of daytime and nighttime warming on alpine treeline recruitment

Trees at their upper range limits are highly sensitive to climate change, and thus alpine treelines worldwide have changed their recruitment patterns in response to climate warming. However, previous studies focused only on daily mean temperature, neglecting the asymmetric influences of daytime and nighttime warming on recruitments in alpine treelines. Here, based on the compiled dataset of tree recruitment series from 172 alpine treelines across the Northern Hemisphere, we quantified and compared the different effects of daytime and nighttime warming on treeline recruitment using four indices of temperature sensitivity, and assessed the responses of treeline recruitment to warming-induced drought stress. Our analyses demonstrated that even in different environmental regions, both daytime and nighttime warming could significantly promote treeline recruitment, and however, treeline recruitment was much more sensitive to nighttime warming than to daytime warming, which could be attributable to the presence of drought stress. The increasing drought stress primarily driven by daytime warming rather than by nighttime warming would likely constrain the responses of treeline recruitment to daytime warming. Our findings provided compelling evidence that nighttime warming rather than daytime warming could play a primary role in promoting the recruitment in alpine treelines, which was related to the daytime warming-induced drought stress. Thus, daytime and nighttime warming should be considered separately to improve future projections of global change impacts across alpine ecosystems.     

岭南垛基果林湿地土壤碳组分特征

岭南垛基果林湿地是珠三角地区典型的湿地类型之一,其对土壤碳汇的贡献值得关注。为探讨果林种植类型对土壤有机碳的影响,对广州垛基果林湿地内种植黄皮(Clausenalansium)(HP),龙眼(Dimocarpuslongan)(LY)、杨桃(Averrhoa carambola)(YT),龙眼和黄皮间种(LH),杨桃、龙眼和黄皮间种(YLH)共5种种植类型下的表层(0～20 cm)土壤碳组分进行研究。结果表明,不同的植被类型对土壤的总有机碳(SOC)、可溶性有机碳(DOC)、微生物生物量碳(MBC)、易氧化有机碳(ROC)、惰性碳(NLC)含量都有影响,LY的SOC含量最高(22.6 g/kg),显著高于YLH (P<0.05),且NLC含量显著高于LH和YLH (P<0.05)。NLC含量与土壤养分呈正相关,与土壤容重呈负相关。YT的MBC含量显著高于LY、HP、LH (P<0.05),且MBC/SOC显著高于HP、LY(P<0.05)。YLH模式下,土壤DOC含量和DOC/SOC显著高于其他植被类型(P<0.05)。LH的ROC/SOC显著高于HP和L...     

野芹菜体细胞胚胎发生早期变化的细胞学研究

通过光学与电子显微镜观察研究了野芹菜(Angelica polymorpha Maxim.)叶柄外植体胚性细胞的起源与原胚状体的发生。叶柄切段植入 MS 2mg/L2,4-D 0.25 mg/L KT固体培养基后,以DNA合成和细胞分裂为指标,判明了胚状体发生与紧贴维管束的鞘细胞层密切相关;鞘细胞通过有丝分裂形成多层结构的细胞群,它们仍含大液泡及薄层胞质,成片被覆在维管束表面;胚性细胞团即不同步地发生在该多层组织较内层的局部位点上,细胞具大核,胞质稠密,经持续有丝分裂发展成大小不同呈瘤状突起的原胚状体。伴随着鞘细胞的剧烈变化,韧皮部薄壁细胞亦分裂增殖,原有筛管变形衰退,部分新增殖的细胞分化为新筛分子;木质部中,原导管束附近朝向韧皮部一侧的部分薄壁细胞亦进一步分化为孔纹导管。外植体中维管系统的再次分化,显然是与输导功能强化以适应原胚状体发生时对营养物质的大量需求有关。     

The complex genome and adaptive evolution of polyploid Chinese pepper (Zanthoxylum armatum and Zanthoxylum bungeanum)

Zanthoxylum armatum and Zanthoxylum bungeanum, known as ‘Chinese pepper’, are distinguished by their extraordinary complex genomes, phenotypic innovation of adaptive evolution and species-special metabolites. Here, we report reference-grade genomes of Z. armatum and Z. bungeanum. Using high coverage sequence data and comprehensive assembly strategies, we derived 66 pseudochromosomes comprising 33 homologous phased groups of two subgenomes, including autotetraploid Z. armatum. The genomic rearrangements and two whole-genome duplications created large (~4.5 Gb) complex genomes with a high ratio of repetitive sequences (>82%) and high chromosome number (2n = 4x = 132). Further analysis of the high-quality genomes shed lights on the genomic basis of involutional reproduction, allomones biosynthesis and adaptive evolution in Chinese pepper, revealing a high consistent relationship between genomic evolution, environmental factors and phenotypic innovation. Our study provides genomic resources and new insights for investigating diversification and phenotypic innovation in Chinese pepper, with broader implications for the protection of plants under severe environmental changes.     

基于转录组测序的宁夏枸杞不同品种果实活性成分合成差异表达基因分析

为探究不同品种宁夏枸杞果实活性成分生物合成相关基因的表达水平,筛选关键差异表达基因(differentially expressed genes,DEGs),揭示宁夏枸杞品种间活性成分含量差异的分子机制,本研究采用Illumina NovaSeq 6000高通量测序技术,对宁夏枸杞‘宁杞1号’和‘宁杞7号’青果期、转色期及成熟期果实进行转录组测序,比较2个品种果实不同发育期相关基因表达谱的变化。结果显示:转录组测序共获得811818178条clean reads,有121.76 Gb有效数据。‘宁杞1号’和‘宁杞7号’在青果期、转色期和成熟期差异表达基因分别有2827、2552和2311个;分别有2153、2050和1825个差异基因在基因本体论(gene ontology,GO)、京都基因与基因组百科全书(Kyoto encyclopedia of genes and genomes,KEGG)富集分析和同源蛋白簇(clusters of orthologous groups of proteins,KOG)分析等6个数据库中被成功注释。青果期、转色期和成熟期果实的差异表达基因,在GO数据库分别有1307、865和624个被富集到生物学过程、细胞组分及分子功能3个部分中;KEGG通路富集结果均集中在代谢途径、次生代谢物生物合成和植物-病原互作过程;在KOG数据库,3个发育期分别注释了1775、1751和1541个差异表达基因。对注释的基因进行PubMed数据库检索,在青果期、转色期和成熟期分别筛选到与枸杞活性成分合成相关的差异表达基因18、26和24个,这些基因主要参与类胡萝卜素、类黄酮、萜类、生物碱和维生素等代谢途径。选取7个差异表达基因进行RT-qPCR验证,结果与转录组测序数据表达趋势一致。本研究从转录水平为不同品种宁夏枸杞活性成分含量差异提供了初步证据,为进一步挖掘枸杞活性成分生物合成的关键基因及解析其表达调控机制提供了研究基础。     

生物可降解塑料单体二元羧酸的生物合成研究进展北大核心CSCD

塑料是最重要的聚合物材料之一,需求量巨大,但存在处理困难、污染大等缺点。环境友好型的生物可降解塑料有望成为目前塑料的替代品,以满足社会各界对于塑料制品日益增长的需求。二元羧酸是生物可降解塑料中重要的单体之一,可降解性强,应用广泛,并且可以通过全生物法合成。因此,本文重点选取了几种比较有代表性的二元羧酸,总结它们的生物合成途径以及其代谢改造手段,以期为中长链等复杂二元羧酸的生物法合成提供借鉴。     

Investigations of interaction mechanism and conformational variation of serum albumin affected by artemisinin and dihydroartemisinin

In this work, binding interactions of artemisinin (ART) and dihydroartemisinin (DHA) with human serum albumin (HSA) and bovine serum albumin (BSA) were investigated thoroughly to illustrate the conformational variation of serum albumin. Experimental results indicated that ART and DHA bound strongly with the site I of serum albumins via hydrogen bond (H-bond) and van der Waals force and subsequently statically quenched the intrinsic fluorescence of serum albumins through concentration-dependent manner. The quenching abilities of two drugs on the intrinsic fluorescence of HSA were much higher than the quenching abilities of two drugs on the intrinsic fluorescence of BSA. Both ART and DHA, especially DHA, caused the conformational variation of serum albumins and reduced the α-helix structure content of serum albumins. DHA with hydrophilic hydroxyl group bound with HSA more strongly, suggesting the important roles of the chemical polarity and the hydrophilicity during the binding interactions of two drugs with serum albumins. These results reveal the molecular understanding of binding interactions between ART derivatives and serum albumins, providing vital information for the future application of ART derivatives in biological and clinical areas.