菜籽饼肥对香蕉枯萎病的防效及其对土壤细菌的影响

研究菜籽饼肥对香蕉枯萎病的防治效果,探究菜籽饼肥施用后对土壤细菌群落的影响.设置2组实验,CN组为菜籽饼肥处理组,YN组为对照实验组.种植120d后,统计各组的发病率;利用qPCR技术检测2组中的FOC4孢子数量;采集2组土壤,利用Illumina Miseq高通量测序平台对CN处理组与YN对照组的土壤细菌群落结构和差异进行分析对比.实验研究发现:(1)施菜籽饼肥的CN处理组枯萎病发病率比YN对照组低63.33％;施用菜籽饼肥的处理土壤中FOC4的数量由2.94×104个/克土下降为1.96×103个/克土,YN对照组土壤中FOC4孢子的数量由2.94×104个/克土上升为4.55×105个/克土,CN处理组较YN对照组枯萎病菌数量下降了 2个数量级;(2)土壤细菌宏基因组微生物分类测序结果显示,CN处理组的Alpha多样性指数均优于YN对照组,这表明施用菜籽饼肥后增加了土壤细菌群落的丰度及多样性;(3)在门水平上,菜籽饼肥处理增加了变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)的相对丰度,同时也降低了酸杆菌门(Acidobact-eria)、厚壁菌门(Firmicutes)和Patescibacteria等菌门的相对丰度;在属水平,CN处理组中的不动杆菌属(Aci-netobacter)、水杆菌属(Aquabacterium)、热单胞菌属(Thermomonas)、产黄杆菌属(Rhodanobacter)、假单胞菌属(Pseudomonas)和奥托氏菌属(Ottowia)等菌属的相对丰度较YN对照组有明显提高,而酸热菌属(Acidother-mus)、Bryobacter菌属以及Acidipila等菌属相对丰度较YN对照组有所减少.施用菜籽饼肥可以改变土壤中细菌的群落结构,显著降低土壤中FOC4孢子数量,从而降低香蕉枯萎病的发病率.本研究结果为菜籽饼肥用于香蕉枯萎病综合防控提供了理论依据.     

"In vitro" protection of DNA from Fenton reaction by plant polyphenol verbascoside

The protection effect of verbascoside (Ver) against Fenton reaction on plasmid pBR322 DNA was studied using agarose gel electrophoresis and UV-visible spectroscopy. The pBR322 plasmid DNA is damaged by hydroxyl radical (OH*) generated from the Fenton reaction with H2O2 and Fe(II) or Fe(III). This DNA damage is characterized by the diminution of supercoiled DNA forms or by the increase of relaxed or linear DNA forms after oxidative attack. The UV spectrum study showed that verbascoside can form complexes with Fe(II) or Fe(III), and the complexation can be reversed by the addition of EDTA. The formation constants of verbascoside-Fe complexes were estimated as 10(21.03) and 10(31.94) M(-2) for Fe(II) and Fe(III) respectively. The inhibition of Fenton reaction by verbascoside could be partially explained by the sequestration of Fe ions.     

巴两橡胶树胶乳黄色体蛋白提取及双向电泳方法初探

巴西橡胶树(Hevea brasiliensis)的黄色体在胶乳凝固和保护植株过程中有重要作用。本文比较使用三氯醋酸/丙酮(TCA/ ACE)、Tris缓冲液、磷酸缓冲液提取橡胶树胶乳黄色体总蛋白的双向电泳效果。确定一种适合双向电泳的蛋白提取方法。结果表明Tris缓冲液提取法得到的双向电泳图谱可以达到300个,尤其是低丰度蛋白呈现性较好,适合提取黄色体蛋白以进行双向电泳。     

Overexpression of HuR, a nuclear-cytoplasmic shuttling protein, increases the in vivo stability of ARE-containing mRNAs.

The messenger RNAs of many proto-oncogenes, cytokines and lymphokines are targeted for rapid degradation through AU-rich elements (AREs) located in their 3'' untranslated regions (UTRs). HuR, a ubiquitously expressed member of the Elav family of RNA binding proteins, exhibits specific affinities for ARE-containing RNA sequences in vitro which correlate with their in vivo decay rates, thereby implicating HuR in the ARE-mediated degradation pathway. We have transiently transfected HuR into mouse L929 cells and observed that overexpression of HuR enhances the stability of beta-globin reporter mRNAs containing either class I or class II AREs. The increase in mRNA stability parallels the level of HuR overexpression, establishing an in vivo role for HuR in mRNA decay. Furthermore, overexpression of HuR deletion mutants lacking RNA recognition motif 3 (RRM 3) does not exert a stabilizing effect, indicating that RRM 3 is important for HuR function. We have also developed polyclonal anti-HuR antibodies. Immunofluorescent staining of HeLa and L929 cells using affinity-purified anti-HuR antibody shows that both endogenous and overexpressed HuR proteins are localized in the nucleus. By forming HeLa-L929 cell heterokaryons, we demonstrate that HuR shuttles between the nucleus and cytoplasm. Thus, HuR may initially bind to ARE-containing mRNAs in the nucleus and provide protection during and after their export to the cytoplasmic compartment.     

Overexpression of the mango MiCO gene delayed flowering time in transgenic Arabidopsis

Plant Cell, Tissue and Organ Culture (PCTOC) - CONSTANS (CO)/CONSTANS-like (COL) genes play an important role in the photoperiodic flowering pathway. However, the functional roles of the CO/COL...     

Systematics of Mukdenia and Oresitrophe (Saxifragaceae): Insights from genome skimming data

Oresitrophe and Mukdenia (Saxifragaceae) are epilithic sister genera used in traditional Chinese medicine. The taxonomy of Mukdenia, especially of M. acanthifolia, has been controversial. To address this, we produced plastid and mitochondrial data using genome skimming for Mukdenia acanthifolia and Mukdenia rossii, including three individuals of each species. We assembled complete plastomes, mitochondrial CDS and nuclear ribosomal ETS/ITS sequences using these data. Comparative analysis shows that the plastomes of Mukdenia and Oresitrophe are relatively conservative in terms of genome size, structure, gene content, RNA editing sites and codon usage. Five plastid regions that represent hotspots of change (trnH-psbA, psbC-trnS, trnM-atpE, petA-psbJ and ccsA-ndhD) are identified within Mukdenia, and six regions (trnH-psbA, petN-psbM, trnM-atpE, rps16-trnQ, ycf1 and ndhF) contain a higher number of species-specific parsimony-informative sites that may serve as potential DNA barcodes for species identification. To infer phylogenetic relationships between Mukdenia and Oresitrophe, we combined our data with published data based on three different datasets. The monophyly of each species (Oresitrophe rupifraga, M. acanthifolia and M. rossii) and the inferred topology ((M. rossii, M. acanthifolia), O. rupifraga) are well supported in trees reconstructed using the complete plastome sequences, but M. acanthifolia and M. rossii did not form a separate clade in the trees based on ETS + ITS data, while the mitochondrial CDS trees are not well-resolved. We found low recovery of genes in the Angiosperms353 target enrichment panel from our unenriched genome skimming data. Hybridization or incomplete lineage sorting may be the cause of discordance between trees reconstructed from organellar and nuclear data. Considering its morphological distinctiveness and our molecular phylogenetic results, we strongly recommend that M. acanthifolia be treated as a distinct species.     

Staphylococcus aureus Lpl protein triggers human host cell invasion via activation of Hsp90 receptor

Staphylococcus aureus is a facultative intracellular pathogen. Recently, it has been shown that the protein part of the lipoprotein‐like lipoproteins (Lpls), encoded by the lpl cluster comprising of 10 lpls paralogue genes, increases pathogenicity, delays the G2/M phase transition, and also triggers host cell invasion. Here, we show that a recombinant Lpl1 protein without the lipid moiety binds directly to the isoforms of the human heat shock proteins Hsp90α and Hsp90ß. Synthetic peptides covering the Lpl1 sequence caused a twofold to fivefold increase of S. aureus invasion in HaCaT cells. Antibodies against Hsp90 decrease S. aureus invasion in HaCaT cells and in primary human keratinocytes. Additionally, inhibition of ATPase function of Hsp90 or silencing Hsp90α expression by siRNA also decreased the S. aureus invasion in HaCaT cells. Although the Hsp90ß is constitutively expressed, the Hsp90α isoform is heat‐inducible and appears to play a major role in Lpl1 interaction. Pre‐incubation of HaCaT cells at 39°C increased both the Hsp90α expression and S. aureus invasion. Lpl1‐Hsp90 interaction induces F‐actin formation, thus, triggering an endocytosis‐like internalisation. Here, we uncovered a new host cell invasion principle on the basis of Lpl‐Hsp90 interaction.