Tomato stigma exsertion induced by high temperature is associated with the jasmonate signalling pathway

High temperature (HT) is becoming an increasingly serious factor in limiting crop production with global climate change. During hot seasons, owing to prevailing HT, cultivated tomatoes are prone to exhibiting stigma exsertion, which hampers pollination and causes fruit set failure. However, the underlying regulatory mechanisms of the HT‐induced stigma exsertion remain largely unknown. Here, we demonstrate that stigma exsertion induced by HT in cultivated tomato is caused by more seriously shortened stamens than pistils, which is different from the stigma exsertion observed in wild tomato species. Under the HT condition, the different responses of pectin, sugar, expansin, and cyclin cause cell wall remodelling and differentially localized cell division and selective cell enlargement, which further determine the lengths of stamens and pistils. In addition, auxin and jasmonate (JA) are implicated in regulating cell division and cell expansion in stamens and pistils, and exogenous JA instead of auxin treatment can effectively rescue tomato stigma exsertion through regulating the JA/COI1 signalling pathway. Our findings provide a better understanding of stigma exsertions under the HT condition in tomato and uncover a new function of JA in improving plant abiotic stress tolerance.     

Differences in Variation of Human Immunodeficiency Virus Type 1 Sequences from Henan and Shanghai Regions of China

Illegally paid blood donation was a risk factor for HIV acquisition exclusively in Henan and Hubei Provinces of China,and not in Shanghai.Nucleotide sequences in the gag and env genes of HIV-1 were compared between isolates from Henan and Shanghai regions of China to test whether an expected higher degree of a common source of infections from this unique blood donation transmission risk would be evident as decreased variation among Henan isolates in an exploratory cross-sectional analysis.Among 38 isolates studied,23 of 23(100%)from Henan and 8 of 15(54%)from Shanghai were subtype B.In addition,fewer sequence differences were found in gp41 of subtype B isolates from Henan than from Shanghai isolates.Further studies with additional controls are therefore warranted to confirm the role of the degree of a common source of infections in differences in HIV variation across populations.     

Differential regulation of cutaneous oncoprotein HPVE6 by wtp53, mutant p53R248W and ΔNp63α is HPV type dependent

UV exposure and p53 mutations are major factors in non-melanoma skin cancer, whereas a role for HPV infections has not been defined. Previous data demonstrated the wtp53-mediated degradation of cutaneous HPV20E6 by caspase-3. ΔNp63α and hot-spot mutant p53R248W conveyed a protective effect on HPV20E6 under these conditions. We demonstrate a differential regulation by wtp53 of the E6 genes of cutaneous types HPV4, HPV5, HPV7, HPV27, HPV38, HPV48, HPV60 and HPV77. Caspase- or proteasome-mediated down-regulation was HPV type dependent. Mutant p53R248W up-regulated expression of all these E6 proteins as did ΔNp63α except for HPV38E6 which was down-regulated by the latter. None of these cellular proteins affected HPV41E6 expression. Ectopic expression of both mutp53R248W and ΔNp63α in the normal NIKS keratinocyte cell line harbouring endogenous p53 and p63however led to a down-regulation of HPV20E6. We demonstrate that HPV20E6 expression in these cells is modulated by additional, yet unidentified, cellular protein(s), which are not necessarily involved in apoptosis or autophagy. We further demonstrate proliferation of HPV20E6-expressing keratinocytes. Levels of proteins involved in cell cycle control, cyclin-D1, cdk6 and p16(INK4a), phosphorylated pRB, as well as c-Jun and p-c-Jun, were all increased in these cells. HPV20E6 did not compete for the interaction between p16(INK4a) with cyclin-D1 or cdk6. Phosphorylation of pRB in the HPV20E6 expressing cells seems to be sufficient to override the cytokenetic block induced by the p16(INK4a)/pRB pathway. The present study demonstrates the diverse influence of p53 family members on individual cutaneous HPVE6 proteins. HPV20E6 expression also resulted in varying protein levels of factors involved in proliferation and differentiation.     

Plasmacytoid dendritic cells in antiviral immunity and autoimmunity

Plasmacytoid dendritic cells (pDCs) represent a unique and crucial immune cell population capable of producing large amounts of type I interferons (IFNs) in response to viral infection. The function of pDCs as the professional type I IFN-producing cells is linked to their selective expression of Toll-like receptor 7 (TLR7) and TLR9, which sense viral nucleic acids within the endosomal compartments. Type I IFNs produced by pDCs not only directly inhibit viral replication but also play an essential role in linking the innate and adaptive immune system. The aberrant activation of pDCs by self nucleic acids through TLR signaling and the ongoing production of type I IFNs do occur in some autoimmune diseases. Therefore, pDC may serve as an attractive target for therapeutic manipulations of the immune system to treat viral infectious diseases and autoimmune diseases.     

稳定同位素分析在鸟类食性及营养级结构中的应用

稳定同位素分析(stable isotope analysis,SIA)自20世纪70年代末引入鸟类生态学领域以来,在研究鸟类食性和营养级结构方面展现了强大的发展潜力和广泛的应用前景。总结了该技术在鸟类食源组成和营养级结构方面研究的前期准备、实验流程、数据分析和研究进展等,重点阐述了其在鸟类保护与管理方面的应用。鉴于稳定同位素在生物体内存在分馏现象,从鸟类不同组织和部位对营养级富集因子、转化周期、同位素印记的差异,提出了完善该方法的建议和应用前景。     

黄芪皂苷IV对H2O2诱导的心肌细胞凋亡的保护作用

目的:探讨黄芪皂苷对H2O2诱导的心肌细胞凋亡的保护作用.方法:以H2O2诱导SD大鼠心肌损伤细胞模型为基础,用黄芪皂苷IV预处理进行干预.MTT法检测不同时段细胞凋亡情况,Western blot和RT-PCR检测24h时段Cyclin D1蛋白和mRNA表达水平.结果:H2O2对SD大鼠心肌细胞的损伤呈时间依赖性.H2O2可显著诱导SD大鼠心肌细胞凋亡.而这一作用可被黄芪皂苷IV显著抑制.结论:黄芪皂苷IV对H2O2诱导的SD大鼠心肌细胞损伤有明显保护作用.     

番茄转化酶抑制子基因克隆及其表达分析

从普通栽培型番茄品种‘桃太郎’、野生醋栗番茄和潘那利番茄的幼苗中采用RT-PCR方法,扩增出转化酶抑制子基因cDNA序列的部分片段。经测序表明：不同基因型番茄的转化酶抑制子基因同源性高达97.97%以上。采用半定量RT-PCR方法对‘桃太郎’苗期根、茎、叶和花后功能叶、花期子房以及果实不同发育阶段不同部位的表达进行检测,结果表明：INH在根中表达较弱,茎中有强烈表达,从幼叶到衰老叶表达逐渐减弱;同一时期INH在果肉中表达相对较强,维管束次之,胶质胎座相对较弱;花期子房中INH的表达逐渐增强,花后3d左右达到最大,花后5～8d表达量迅速下降。     

五爪金龙乙醇提取物对福寿螺毒杀和水稻苗生长的影响

福寿螺和五爪金龙是两种危害严重的入侵生物,利用五爪金龙防治稻田福寿螺是以害治害的方法.盆栽条件下研究了五爪金龙乙醇提取物毒杀福寿螺的效果,以及其对水稻苗生长的影响.在砂培条件下五爪金龙乙醇提取物及其分离得到的甲醇相、乙酸乙酯相、乙醚相水溶液不仅对福寿螺起到毒杀作用, 而且对水稻秧苗生长有促进作用, 毒杀和促进作用由强到弱的顺序均为:乙醇提取物>甲醇相>乙酸乙酯相>乙醚相.在实验浓度范围内五爪金龙乙醇提物对福寿螺的毒杀效果及其对水稻苗促进作用强度均随浓度的增大而增强,在水稻土盆栽条件下抑制福寿螺取食水稻苗的效果与密达差异不显著(p>0.05).五爪金龙乙醇提取物能毒杀福寿螺,对水稻苗的生长没有不利的影响.因此, 利用五爪金龙防治稻田福寿螺危害是环境友好的非化学防治措施,具有良好的应用前景.     

兼性肠球菌Enterococcus hirae AUH-HM195对黄豆苷原的开环转化

摘要：【目的】从褐马鸡粪样中分离对大豆异黄酮黄豆苷原具有转化作用的功能微生物菌株。【方法】在厌氧工作站内对褐马鸡新鲜粪样进行梯度稀释后涂板,从板上挑取单菌落与底物黄豆苷原厌氧混合培养,用高效液相色谱检测底物被转化情况。【结果】分离出一株对黄豆苷原具开环转化作用的革兰氏阳性兼性好氧菌株AUH-HM195（EU919863）,经BLAST比对,该菌株的16S rDNA基因全序与肠球菌属菌株Enterococcus hirae (DSM20160) 的相似性为100%。根据保留时间、代谢产物最大紫外吸图谱以及核