马兜铃不含腋芽茎段不定芽的诱导

为建立马兜铃(Aristolochia debilis Sieb.et Zucc)不含腋芽茎段的不定芽诱导体系,采用正交设计方法研究植物生长调节剂、预培养方式和AgNO3对不定芽诱导的影响。结果表明:植物生长调节物质对不定芽诱导的影响以TDZ6-BAIAA,其中TDZ的影响极显著(P0.01),6-BA的影响显著(P0.05)。不定芽诱导的最适培养基为MS+0.5 mg L–1 TDZ+0.1 mg L–1IAA+0.5 mg L–1 6-BA+2 mg L–1 AgNO3+3%蔗糖+0.6%琼脂(pH 5.8);预培养方式为在MS+0.1 mg L–1 2,4-D+3%蔗糖+0.6%琼脂培养基上暗培养2 d。马兜铃不含腋芽茎段的不定芽诱导率最高可达37.5%。     

Human Tau may Modify Glucocorticoids-Mediated Regulation of cAMP-dependent Kinase and Phosphorylated cAMP Response Element Binding Protein

Phosphorylation of the cAMP response element binding protein (CREB) by cAMP-dependent kinase (PKA) is critical to memory formation. However, activation of PKA can also increase tau phosphorylation, which may contribute to memory impairment. Therefore, the regulation of PKA may be part of the mechanism by which glucocorticoids (GCs) influence memory. Additionally, the cellular response to GCs may be affected by the presence of human tau. The goal of this paper was to study GCs-mediated regulation of PKA as well as CREB and tau phosphorylation in wild-type HEK293 cells and HEK293 cells stably expressing human tau441 (HEK293/tau441 cells). By using dexamethasone (DEX) as GCs, we found that DEX induced a tau-dependent selective decrease in the level of PKA RIIβ subunit protein. The observed decrease in RIIβ expression was not due to alterations of mRNA levels and was reversed by inhibiting the proteasome with lactacystin. Moreover, the decrease in RIIβ did not diminish the co-localization of the catalytic subunit of PKA with tau and might contribute to the DEX-induced increase in tau phosphorylation at Ser-214. DEX also induced a tau-dependent decrease in CREB phosphorylation that could not be reversed by activating PKA with forskolin. Taken together, these results show that human tau protein may alter the GCs-mediated regulation of PKA activity and CREB phosphorylation.     

Quantitative trait locus analysis of lateral branch-related traits in cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.) using recombinant inbred lines

A group of 224 recombinant inbred lines (RILs) was derived from a narrow cross between 2 cucumber (Cucumis sativus L.) lines, namely, S94 (Northern China type with weak lateral branch growth potential and early lateral branch sprouting time) and S06 (Northern European type with strong lateral branch growth potential and late lateral branch sprouting time). These lines were then used for investigating lateral branch-related traits. A total of 36 quantitative trait loci (QTLs) were detected for the following 4 lateral branch-related traits: lateral branch average length (LBAL), lateral branch total length (LBTL), lateral branch number (LBN), and first lateral branch node (FLBN). Further, each QTL explained 3.1% (lbtl2.1, spring) to 32.3% (lbn2.3, spring) of the observed phenotypic variance. Eleven QTLs (lbal1.1, lbtl1.1, lbn1.2, flbn1.2, etc.) for different traits were found to be clustered on the e23m18d-ME23EM6c section (7.4 cM) of linkage group (LG) 1; further, 15 QTLs (lbal2.1, lbtl2.1, lbn2.1, flbn2.1, etc.) were found to be clustered on the S94A1-ME4SA4a section (13.9 cM) of LG2. Twenty-one QTLs explained more than 10% of the phenotypic variance. Moreover, lbtl1.3 (autumn, 26.2%, logarithm of odds (LOD) = 17.4; spring, 26.9%, LOD = 17.9) had stable position and contribution in both seasons. Several sequence-anchor markers (CMBR40, F, CS30, S94A1, CSWTA11B, etc.) were closely linked with some QTLs for LBAL, LBTL, LBN, and FLBN, which can be used for the marker-assisted selection to improve the plant architecture in cucumber breeding.     

一种基于链霉素沉淀的PrPSc检测方法的建立

建立一种新的基于链霉素沉淀的PrPSc的Western blot检测方法,用终浓度为60 mmol/L的链霉素处理蛋白酶K消化的PrPSc贮存液,通过离心沉淀PrPSc,用Western blot对PrPSc的链霉素富集效果进行检测.结果显示,链霉索能够与PrPSc结合形成高分子量复合物,但不影响糖基化形式.此外,基于链霉素沉淀的Western blot,无论是在低浓度或是大容积的条件下,均可显著地提高对PrPSc检测的敏感性.基于链霉素沉淀的Western blot试验是一种敏感、特异、快速及灵活的检测方法,有潜力用于脑组织、外周组织及体液中低水平的PrPSc的检测.     

Development and fine mapping of three co-dominant SCAR markers linked to the <Emphasis Type="Italic">M/m</Emphasis> gene in the cucumber plant (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.)

Owing to its diverse sex types, the cucumber plant has been studied widely as a model for sex determination. In addition to environmental factors and plant hormones, three major genes—F/f, M/m, and A/a—regulate the sex types in the cucumber plant. By combining the bulked segregant analysis (BSA) and the sequence-related amplified polymorphism (SRAP) technology, we identified eight markers linking to the M/m locus. Among them, the two closely linked SRAP markers flanking the M/m locus were the co-dominant marker ME1EM26 and the dominant marker ME1EM23. Further, the co-dominant marker ME8SA7 co-segregated with the M/m locus. With the chromosome walking method using the cucumber genomic bacterial artificial chromosome (BAC) library, we successfully developed a co-dominant SCAR marker S_ME1EM23 from the ME1EM23 sequence. Along with the other two co-dominant SCAR markers S_ME1EM26 and S_ME8SA7 (developed from ME1EM26 and ME8SA7, respectively) in a larger segregating population (900 individuals), the M/m locus was mapped between S_ME1EM26 (5.4 cM) and S_ME1EM23 (0.7 cM), and S_ME8SA7 co-segregated with it. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Z. Li and J. Pan contribute equally to this article.     

Vagal nerve stimulation improves mitochondrial dynamics via an M3 receptor/CaMKKβ/AMPK pathway in isoproterenol‐induced myocardial ischaemia

Mitochondrial dynamics—fission and fusion—are associated with ischaemic heart disease (IHD). This study explored the protective effect of vagal nerve stimulation (VNS) against isoproterenol (ISO)‐induced myocardial ischaemia in a rat model and tested whether VNS plays a role in preventing disorders of mitochondrial dynamics and function. Isoproterenol not only caused cardiac injury but also increased the expression of mitochondrial fission proteins [dynamin‐related peptide1 (Drp1) and mitochondrial fission protein1 (Fis‐1)) and decreased the expression of fusion proteins (optic atrophy‐1 (OPA1) and mitofusins1/2 (Mfn1/2)], thereby disrupting mitochondrial dynamics and leading to increase in mitochondrial fragments. Interestingly, VNS restored mitochondrial dynamics through regulation of Drp1, Fis‐1, OPA1 and Mfn1/2; enhanced ATP content and mitochondrial membrane potential; reduced mitochondrial permeability transition pore (MPTP) opening; and improved mitochondrial ultrastructure and size. Furthermore, VNS reduced the size of the myocardial infarction and ameliorated cardiomyocyte apoptosis and cardiac dysfunction induced by ISO. Moreover, VNS activated AMP‐activated protein kinase (AMPK), which was accompanied by phosphorylation of Ca²⁺/calmodulin‐dependent protein kinase kinase β (CaMKKβ) during myocardial ischaemia. Treatment with subtype‐3 of muscarinic acetylcholine receptor (M₃R) antagonist 4‐diphenylacetoxy‐N‐methylpiperidine methiodide or AMPK inhibitor Compound C abolished the protective effects of VNS on mitochondrial dynamics and function, suggesting that M₃R/CaMKKβ/AMPK signalling are involved in mediating beneficial effects of VNS. This study demonstrates that VNS modulates mitochondrial dynamics and improves mitochondrial function, possibly through the M₃R/CaMKKβ/AMPK pathway, to attenuate ISO‐induced cardiac damage in rats. Targeting mitochondrial dynamics may provide a novel therapeutic strategy in IHD.     

LncRNA‐PAGBC acts as a microRNA sponge and promotes gallbladder tumorigenesis

Long noncoding RNAs (lncRNAs) play roles in the development and progression of many cancers; however, the contributions of lncRNAs to human gallbladder cancer (GBC) remain largely unknown. In this study, we identify a group of differentially expressed lncRNAs in human GBC tissues, including prognosis‐associated gallbladder cancer lncRNA (lncRNA‐PAGBC), which we find to be an independent prognostic marker in GBC. Functional analysis indicates that lncRNA‐PAGBC promotes tumour growth and metastasis of GBC cells. More importantly, as a competitive endogenous RNA (ceRNA), lncRNA‐PAGBC competitively binds to the tumour suppressive microRNAs miR‐133b and miR‐511. This competitive role of lncRNA‐PAGBC is required for its ability to promote tumour growth and metastasis and to activate the AKT/mTOR pathway. Moreover, lncRNA‐PAGBC interacts with polyadenylate binding protein cytoplasmic 1 (PABPC1) and is stabilized by this interaction. This work provides novel insight on the molecular pathogenesis of GBC.