Zucchini Yellow Fleck Virus is an Emergent Virus on Melon in Sicily (Italy)

Since 2006, winter melon plants (Cucumis melo L. var inodorus) showing symptoms of pin‐point yellow spots were noticed in Sicily (Italy). Leaf samples were tested by enzyme‐linked immunosorbent assay to the most important viruses‐infecting cucurbits. Zucchini yellow fleck virus (ZYFV, genus Potyvirus) was the only virus detected. Surveys in 2007 and 2008 revealed an increasing number of sites in Sicily with ZYFV‐infected winter melon plants. To confirm the identity of the virus as ZYFV, two isolates from different locations were sequenced and shown to be approximately 85% identical to the published sequences of isolates previously identified in Italy and France. This is the first report of ZYFV occurring on melon in Italy.     

苦杏仁精油对粘虫的触杀活性研究

以粘虫4龄幼虫为对象,采用"点滴法"研究了山杏种仁两种苦杏仁精油(含HCN和去HCN)对粘虫的触杀活性及其生长发育的影响.结果显示,处理后48 h,5～100 μL/mL浓度处理的试虫死亡率均在51.67%以上,40和100 μL/mL浓度处理的粘虫死亡率分别达到了95%(含HCN)/98.33%(去HCN)和100%,48 h时含HCN与除去HCN两种苦杏仁精油对粘虫的触杀致死中浓分别为5.10和4.69 μL/mL;苦杏仁精油对粘虫的化蛹期以及羽化期提前1～3 d,并有一定数量的畸形蛹出现,部分试虫虽能正常化蛹并羽化,但其蛹以及成虫虫体均较对照小,且羽化后蛾体萎缩,活动力降低,因展翅困难而死.可见,两种苦杏仁精油对粘虫具有很强的触杀活性,且去HCN的苦杏仁精油对粘虫的活性高于含HCN的苦杏仁精油,其对粘虫生长发育抑制活性主要表现化蛹期以及羽化期提前,苦杏仁精油有望发展为植物性杀虫剂.     

苦杏仁精油的熏蒸杀虫活性研究

采用三角瓶密闭熏蒸法测定了苦杏仁精油对家蝇、白纹伊蚊、粘虫以及玉米象的熏蒸杀虫活性,结果显示:苦杏仁精油对各试虫均有较强的熏蒸杀虫活性,其中含HCN的精油对家蝇、白纹伊蚊、粘虫以及玉米象的LC50分别为3.09、0.63、4.63、12.03μL/L;除去HCN的精油对家蝇、白纹伊蚊、粘虫以及玉米象的LC50分别为3.53、0.52、4.08、23.46μL/L;熏蒸的时间效应试验结果表明,含有HCN的苦杏仁精油和不含HCN的苦杏仁精油对供试试虫的熏杀速度均较快,其中白纹伊蚊的反应最快,其次为家蝇、粘虫、玉米象.除玉米象外苦杏仁精油中所含的微量HCN对试虫的熏蒸活性影响不大,且2种处理的精油对同种试虫的致死中时差别范围不超过10 min.实验结果表明,苦杏仁精油可作为新型的杀虫活性物质,为苦杏仁精油作为植物源杀虫剂提供了依据.     

Quantitative structure-activity relationship study of bitter di- and tri-peptides including relationship with angiotensin I-converting enzyme inhibitory activity.

Bitterness represents a major challenge in industrial application of food protein hydrolysates or bioactive peptides and is a major factor that controls the flavor of formulated therapeutic products. The aim of this work was to apply quantitative structure-activity relationship modeling as a tool to determine the type and position of amino acids that contribute to bitterness of di- and tri-peptides. Datasets of bitter di- and tri-peptides were constructed using values from available literature, followed by modeling using partial least square (PLS) regression based on the three z-scores of 20 coded amino acids. Prediction models were validated using cross-validation and permutation tests. Results showed that a single-component model could explain 52 and 50% of the Y variance (bitterness threshold) of bitter di- and tri-peptides, respectively. Using PLS regression coefficients, it was determined that hydrophobic amino acids at the carboxyl-terminus and bulky amino acid residues adjacent to the carboxyl terminal are the major determinants of the intensity of bitterness of di- and tri-peptides. However, there was no significant (p > 0.05) correlation between bitterness of di- and tri-peptides and their angiotensin I-converting enzyme-inhibitory properties.     

First Report of Greeneria uvicola Causing Bitter Rot of Grape in China

In 2013, bitter rot of grape was observed in Changbei Vineyard located in Nanchang City, Jiangxi Province, China. Greeneria species was consistently isolated from the diseased grape berries (Vitis labruscana cv. Kyoho) at approximately 91% of isolation rate in three independent experiments. The species was identified as Greeneria uvicola based on the morphological characteristics, cultural appearance and sequence analysis. Koch's postulates were fulfilled through pathogenicity tests on detached healthy Kyoho grape berries. To our knowledge, this is the first report of G. uvicola causing bitter rot of grape in China.     

外源γ-氨基丁酸调控甜瓜叶绿体活性氧代谢应对短期盐碱胁迫

以甜瓜品种‘金辉1号’为试材,采用深液流水培法,研究外源γ 氨基丁酸(GABA)对短期盐碱胁迫下甜瓜幼苗叶绿体活性氧代谢的调控作用.结果表明: 盐碱胁迫显著提高了甜瓜叶绿体内光合色素、丙二醛(MDA)和过氧化氢(H₂O₂)含量及超氧阴离子(O^-_·2)产生速率;增加抗坏血酸(AsA)和谷胱甘肽(GSH)等抗氧化物质含量;明显抑制H⁺-ATP酶(H⁺-ATPase)和H⁺ 焦磷酸酶(H⁺-PPiase)活性.外源叶面喷施GABA有效抑制了盐碱胁迫引起的叶绿体内O^-_·2、H₂O₂和MDA的积累,缓解了光合色素增加的趋势;显著提高SOD和AsA GSH循环各个酶的活性,增加了AsA和GSH库,降低了AsA/DHA和GSH/GSSH比值,增强了H⁺-ATPase和H⁺-PPiase 活性.表明外源GABA能加快叶绿体内活性氧代谢,促进AsA-GSH循环的运转,维持细胞膜的渗透性,进而缓解了盐碱胁迫引起的氧化伤害.     

甜瓜果实糖含量相关性状QTL分析

以高糖栽培亲本自交系‘0246’为母本,低糖野生亲本自交系‘Y101’为父本,通过杂交得到了含135个单株的甜瓜远缘F2群体,分别测定甜瓜果实果糖、葡萄糖和蔗糖含量,将三者之和作为总糖含量,进行遗传连锁图谱构建及QTL分析。结果表明:(1)构建的甜瓜果实遗传图谱包含14个连锁群,覆盖基因组长度726.30cM,标记间平均距离为12.74cM。(2)检测到与总糖含量和果糖含量相关的QTL位点各1个,分别命名为Ts3.1和Fru4.1,贡献率分别为14.89%和13.02%,分布于第3、4连锁群,LOD值分别为3.60和3.10。2个QTL位点均为正向加性遗传,分别对增加总糖和果糖含量表现为增效累加效应。研究结果为开展甜瓜糖含量相关基因精细定位和克隆研究奠定了基础。     

Saponins from the traditional medicinal plant Momordica charantia stimulate insulin secretion in vitro

The antidiabetic activity of Momordica charantia (L.), Cucurbitaceae, a widely-used treatment for diabetes in a number of traditional medicine systems, was investigated in vitro. Antidiabetic activity has been reported for certain saponins isolated from M. charantia. In this study insulin secretion was measured in MIN6 β-cells incubated with an ethanol extract, saponin-rich fraction, and five purified saponins and cucurbitane triterpenoids from M. charantia, 3β,7β,25-trihydroxycucurbita-5,23(E)-dien-19-al (1), momordicine I (2), momordicine II (3), 3-hydroxycucurbita-5,24-dien-19-al-7,23-di-O-β-glucopyranoside (4), and kuguaglycoside G (5). Treatments were compared to incubation with high glucose (27 mM) and the insulin secretagogue, glipizide (50 μM). At 125 μg/ml, an LC-ToF-MS characterized saponin-rich fraction stimulated insulin secretion significantly more than the DMSO vehicle, p=0.02. At concentrations 10 and 25 μg/ml, compounds 3 and 5 also significantly stimulated insulin secretion as compared to the vehicle, p≤0.007, and p=0.002, respectively. This is the first report of a saponin-rich fraction, and isolated compounds from M. charantia, stimulating insulin secretion in an in vitro, static incubation assay.     

Building a tree of knowledge: analysis of bitter molecules

A phylogenetic-like tree of structural fragments has been constructed to extract useful insights from a structural database of bitter molecules. The tree of structural fragments summarizes the substructural groups present in the molecules from the bitter database. These structural fragments are compared with a large number of random molecules to highlight substructures specific to bitter molecules. This organization of the structures enabled the detection of structure-activity relationships for the bitter molecules through the construction of R-tables. Key structural groups, able to distinguish between bitter and random molecules, were identified through an analysis of the tree. This information can be used to further understand which structural components are involved in producing a bitter taste.