Lyngbyastatins 8–10, Elastase Inhibitors with Cyclic Depsipeptide Scaffolds Isolated from the Marine Cyanobacterium Lyngbya semiplena

Investigation of an extract from the marine cyanobacterium Lyngbya semiplena, collected in Tumon Bay, Guam, led to the identification of three new cyclodepsipeptides, lyngbyastatins 8–10 (1–3). The structures of 1–3 were determined by NMR, MS, ESIMS fragmentation and chemical degradation. Compounds 1–3 are closely related to lyngbyastatins 4–7. Like the latter compounds, we found 1–3 to inhibit porcine pancreatic elastase, with IC₅₀ values of 123 nM, 210 nM and 120 nM, respectively.     

Preparation and antinutritional characteristics of dry bean (Phaseolus vulgaris L.) protein concentrates

Protein concentrates and starches were prepared by a wet extraction process from five dry bean (Phaseolus vulgaris L.) cultivars. The protein contents ranged from 69.7–76.4%. Concentrates prepared from dehulled beans under similar conditions had higher protein contents (80.6–87.9%). Each additional washing of the concentrates with distilled water increased their protein content. However, the protein recovery progressively decreased. The yield of starch ranged from 48.0–51.1% of the starting material. The solubility of bean proteins was minimal at pH 4.0, and under alkaline conditions, it was influenced by the tannin contents of the concentrates. Protein concentrates had lower trypsin, chymotrypsin, and amylase inhibitory activities as well as lower phytic acid and tannin contents compared to whole bean flours.     

The tryptophan-rich domain of puroindoline is directly associated with the starch granule surface as judged by tryptic shaving and mass spectrometry

The starch granule surface is a frontline of microbial attack and defence, operating in the background of normal starch granule metabolism. Puroindoline, a wheat protein which binds starch granule surfaces, contains a unique tryptophan-rich domain likely responsible for this property, though direct evidence is lacking. To test puroindoline’s tight association, prime starch granule extracts were water-washed 8 or 20 times and residual puroindoline removed using a solution of 50% isopropanol/50 mM NaCl. We found that this solvent was consistent in the amount of protein extracted from wheat flour and washed starch, regardless of initial protein content. Relative quantification of puroindoline following water-washing was performed using dot blot. Washing more than 8 times did not further reduce puroindoline content of starch granules suggesting a strong association with the starch granule surface. To identify the tryptophan-rich domain tightly associated with the starch granule surface, a combination of in situ tryptic digestion and mass spectrometry was used. Following digestion and water-washing, 50% isopropanol/50 mM NaCl was used to remove tightly-associated peptides for identification by mass spectrometry. Using this method, we identified the tryptophan-rich domain of puroindoline directly bound to the starch granule surface of wheat.     

Effect of Acibenzolar-S-methyl (ASM) pre-treatment in inducing resistance against Pythium aphanidermatum infection in Curcuma longa

In vitro experiments were carried out to test the efficacy of plant activator Acibenzolar-S-methyl (ASM, a benzothiadiazole derivative; trade name Bion 50WG) against rhizome rot disease of turmeric (Curcuma longa L.) caused by Pythium aphanidermatum. The plant activator was applied as a liquid rhizome pre-treatment followed by inoculation with P. aphanidermatum. Cell death, activities of pathogenesis related (PR) proteins such as cysteine protease (EC 3.4.22), peroxidases (EC 1.11.1.7) both soluble and ionically bound (IB), trypsin inhibitor (EC 3.4.21.1) and chymotrypsin inhibitor (EC 3.4.21.4) were monitored. Rhizome pre-treatment was effective in controlling P. aphanidermatum infection. Anatomical observation of turmeric rhizomes indicated the presence of calcium oxalate deposits in infected tissue and an accumulation of starch grains in response to infection by P. aphanidermatum. Pathogen infection also induced new basic polypeptides corresponding to 18.0 and 41.0 kDa. Induction of protease, protease inhibitors, soluble and ionically bound peroxidase activity was observed after ASM pre-treatment and P. aphanidermatum infection. ASM treatment also enhanced activities of proteases and peroxidase in rhizomes already infected with P. aphanidermatum. Increases in enzyme activities and protease inhibitors occurred much more rapidly and were enhanced in P. aphanidermatum infected rhizomes that were previously treated with ASM suggesting that increased activities of peroxidases and protease inhibitors may play a key role in restricting the development of disease symptoms on the rhizomes infected with P. aphanidermatum as evidenced by a reduction in cell death. Hence, pretreatment with ASM suppress the P. aphanidermatum induced oxidative damage through higher accumulation of peroxidases and induced defense through activities of protease inhibitors thereby, protected turmeric rhizomes from rhizome rot disease.     

黑龙江省稻稗对丁草胺的抗性测定及交互抗性的研究

【目的】明确黑龙江省水田稻稗(Echinochloa oryzicola Vasing)对丁草胺的抗药性水平以及对其他细胞分裂抑制剂的交互抗药性水平。【方法】采用琼脂法和整株盆栽法测定了黑龙江省14个地区53个田块的稻稗对丁草胺的抗药性以及对其他3种细胞分裂抑制剂丙草胺、苯噻酰草胺和莎稗磷的交互抗性。【结果】琼脂法检测出庆安03、东京城镇02等4个稻稗生物型对丁草胺产生了中等水平抗性，抗性指数为12.92~26.03，占供试稻稗生物型的7.55%；兴隆镇03、阿城04等4个稻稗生物型对丁草胺产生了低等水平抗性，抗性指数为6.63~8.86，占供试稻稗生物型的7.55%；庆安01、汤原01等5个稻稗生物型对丁草胺敏感性下降，抗性指数为3.18~4.84，占供试稻稗生物型的9.43%；其余阿城02、尚志02等40个稻稗生物型对丁草胺表现敏感，抗性指数均小于3，占供试稻稗生物型的75.47%。选取上述测定结果当中抗性最高的两个生物型，使用整株盆栽法进行对丁草胺的抗性水平验证。发现庆安03和东京城镇02同样产生了中等水平抗性，抗性指数分别为16.78和13.27；同时测定两个抗性生物型对丙草胺、苯噻酰草胺和莎稗磷3种细胞分裂抑制剂的交互抗性，结果显示，庆安03稻稗生物型对丁草胺和丙草胺产生了交互抗性；东京城镇02稻稗生物型对丁草胺、丙草胺和莎稗磷产生了交互抗性。【结论】黑龙江省部分地区稻稗对丁草胺产生了抗药性，且对丙草胺和莎稗磷产生了交互抗性。     

几种药剂对小麦黄矮病的防治效果

为明确病毒抑制剂对小麦黄矮病的预防和防治效果,在小麦起身期将大麦黄矮病毒GAV株系接种于小麦陕恳9740上,喷施杀虫剂(2.5%吡虫啉可湿性粉剂2000倍液)与病毒抑制剂(20%病毒A可湿性粉剂500倍液、3.95%病毒必克可湿性粉剂500倍液、5%菌毒清水剂500倍液和2%菌克毒克水剂300倍液)的不同组合,于小麦开花期统计发病率、病情指数和小麦叶片黄化率,结果表明,各组合均能早期预防和防治小麦黄矮病发生和发展,且预防效果优于防治效果,其中病毒必克与吡虫啉组合的平均预防和防治效果最显著,分别为58.08%和53.03%.进一步利用病毒必克在室内进行防治性试验,发现病毒必克能够抑制GAV对叶绿素的破坏,可减轻大麦黄矮病毒对小麦的危害.     

Changes in trypsin and chymotrypsin inhibitory activity on soaking of sorghum (Sorghum bicolor L. Moench)

Changes in trypsin and chymotrypsin inhibitory activity of sorghum (Sorghum bicolor L. Moench) seeds on soaking in distilled water, different salt solutions and mixed salt solution were investigated. A greater reduction in proteinase inhibitory activity was observed on soaking in salt solution than on soaking in distilled water. Maximum loss of trypsin and chymotrypsin inhibitory activity was observed on soaking seeds in mixed salt solution.     

酶法提取猕猴桃皮和渣中果胶的工艺研究

[目的]去除猕猴桃皮和渣中的淀粉和蛋白质,提取并制备膳食食用果胶。[方法]通过单因素和正交试验设计,分别确定0.4%淀粉酶和0.4%胰蛋白酶提取猕猴桃皮和渣中果胶的适宜工艺条件。[结果]0.4%淀粉酶可有效去除猕猴桃皮和渣中的淀粉,其适宜工艺条件为：料液比1∶10.0,50℃下酶解60 min;0.4%胰蛋白酶可有效去除猕猴桃皮和渣中的蛋白质,其适宜工艺条件为：料液比1∶10.0,35℃下酶解60 min。在最佳工艺条件下,经离心、浓缩得到果胶,其中猕猴桃皮和渣中的果胶得率分别为3.10%和1.39%。[结论]通过改良酶法,建立了猕猴桃皮和渣中果胶提取的适宜工艺。     

大麦根中多胺含量和转化与耐盐性的关系

用0、50、100、200和300mmol·L-1NaCl对2个耐盐性不同的大麦品种鉴4(J4,耐盐性较强)和科品7号(KP7,耐盐性较弱)幼苗处理8d后,其干重均随着NaCl浓度增加而显著下降,叶片MDA含量和相对电导率相应增加。与对照相比,J4干重的降低要小于KP7,MDA含量和相对电导率也比KP7低。在盐胁迫下,大麦幼苗根系的多胺含量和种类也有显著的变化,随NaCl浓度的增加,腐胺(Put)含量先下降后上升,而亚精胺(Spd)含量的变化则相反,这种多胺含量变化的盐浓度阈值J4大于KP7。多胺合成抑制剂D-Arg、二氟甲基鸟氨酸(DFMO)和甲基乙二醛双(鸟嘌呤腙)(MGBG)可以显著降低盐胁迫下多胺含量,不同程度上加重了盐胁迫的伤害,表明植物体内多胺在盐胁迫适应中具有重要的作用。