Aplysia sea hare assimilation of secondary metabolites from brown seaweed,Stypopodium zonale

JuvenileAplysia dactylomela were found feeding in abundance on the tropical brown algaStypopodium zonale, a seaweed previously shown to contain numerous unique terpene-quinone natural products. Lipid extracts of these herbivorous mollusks were shown by TLC and HPLC-NMR analyses to contain appreciable quantities of twoS. zonale metabolites as well as one new but closely related compound. Spectroscopic analyses of the new compound in concert with functional group modifications identified this new compound as 3-keto epitaondiol. A careful analysis of the seaweed extract failed to locate this ketone, and thus, it most likely represents anAplysia-biotransformed compound. This is the first clear reported observation of metabolite transfer between an alga of the phylum Phaeophyta and a sea hare.     

Physiological and behavioral effects of coniferyl benzoate on avian reproduction

Various plant secondary metabolites related to cinnamic acid are of interest because of their repellency to birds and their occurrence in ecologically important food items. Coniferyl benzoate (CB), a phenylpropanoid ester that occurs in quaking aspen (Populus tremuloides) is of particular ecological interest because of its effect on ruffed grouse (Bonasa umbellus) feeding behavior and its possible influence on the population dynamics of this bird. During detoxification processes, CB and other analogous compounds are metabolized into by-products, such as ferulic acid (FA), that can cause anti-reproductive effects. We tested whether consumption of CB produces antire-productive effects similar to FA using male and female Japanese quail (Coturnix coturnix) as avian models for ruffed grouse. The parameters we investigated included: the production, morphology, and development of eggs; reproductive characteristics influenced by estrogen; serum prolactin levels; and male reproductive behavior. Dietary CB did not produce antireproductive effects similar to FA at intake levels that Japanese quail and ruffed grouse would freely consume. Consumption of CB by Japanese quail significantly reduced egg production and body mass but did not affect male reproductive performance. Coniferyl benzoate's effect on egg production may be explained by lower energy acquisition and retention rather than endocrine changes per se. Contrary to previous reports, it is unlikely that FA, or similar compounds act directly as estrogen mimics or antagonists. Although, CB did reduce egg production in quail, it is unlikely that it would affect egg production in wild ruffed grouse. Detoxification costs and the effects of CB on nutrient utilization may explain why ruffed grouse avoid high dietary levels of CB.     

电喷雾串联质谱法分析阿托品在大

用液相色谱-电喷雾离子阱串联质谱(LC-ESIIT-MSn)联用法研究阿托品在大鼠肠内菌中的代谢,以阿托品优化色谱及质谱条件,总结其色谱及质谱行为规律。将阿托品与大鼠肠内菌体外厌氧温孵培养,与空白样品及阿托品标准品相比较,根据被测物的多级质谱数据,鉴定代谢物并阐述其结构。在温孵液中发现了阿托品的脱水及水解代谢产物,即脱水阿托品、托品和托品酸。该方法灵敏、快速、简单,适合于药物代谢分析。     

用核糖体工程技术二次开发海洋微生物菌株资源的研究

经对无活性的海洋来源放线菌B3054进行链霉素抗性筛选,获得了一株具有抗肿瘤活性的链霉素抗性突变株SY-1.从该突变株的发酵物中分离得到了4个活性化合物,其中1个为新天然产物.对该菌株突变前后的rpsL基因(编码核糖体蛋白S12)进行分析未发现发生突变,提示突变位点可能在核糖体的另外亚基上.实验结果表明,核糖体工程技术可用于无活性菌株资源的二次开发利用.     

微生物源食品保鲜剂的研究进展

目的 介绍近5年微生物源食品保鲜剂的研究进展,为研究高效、无毒、天然的食品保鲜剂提供理论和方法依据.方法 综述常见的微生物源食品保鲜剂,包括细菌源保鲜剂、真菌源保鲜剂和微生物代谢产物保鲜剂(乳酸链球菌素、￡-聚赖氨酸、溶菌酶和纳他霉素).简要说明其抑菌机理和存在的问题.结果 微生物源保鲜剂可以通过竞争营养,诱导系统抗性和产生活性代谢产物等方式抑制多种致病菌的生长繁殖,降低果蔬病害的发生率,保持食品良好的感官品质和理化特性,有效延长食品货架期.结论 微生物源保鲜剂为食品保鲜贮藏提供了新途径.其抑菌机理和潜在毒性需进一步明确,如何提高微生物源保鲜剂抗不良环境的稳定性还有待进一步研究.     

Plant Responses to Herbivory,Wounding, and Infection

Plants have various self-defense mechanisms against biotic attacks, involving both physical and chemical barriers. Physical barriers include spines, trichomes, and cuticle layers, whereas chemical barriers include secondary metabolites (SMs) and volatile organic compounds (VOCs). Complex interactions between plants and herbivores occur. Plant responses to insect herbivory begin with the perception of physical stimuli, chemical compounds (orally secreted by insects and herbivore-induced VOCs) during feeding. Plant cell membranes then generate ion fluxes that create differences in plasma membrane potential (Vm), which provokes the initiation of signal transduction, the activation of various hormones (e.g., jasmonic acid, salicylic acid, and ethylene), and the release of VOCs and SMs. This review of recent studies of plant–herbivore–infection interactions focuses on early and late plant responses, including physical barriers, signal transduction, SM production as well as epigenetic regulation, and phytohormone responses.     

营养液低氧胁迫对网纹甜瓜幼苗生长和生理代谢影响

在水培条件下,研究了营养液低氧胁迫对网纹甜瓜幼苗生长指标、光合作用和生理代谢物质含量的影响。结果表明,低氧处理显著抑制了幼苗的生长,鲜重、干重等生长指标和叶绿素含量、净光合速率等光合指标均显著降低;低氧胁迫诱导幼苗不定根和根系活力显著增加;低氧胁迫下幼苗MDA、H2O2含量显著增加,但是幼苗体内可溶性糖、氨基酸、游离态多胺和热稳定蛋白含量也显著提高。与西域一号相比,星光生长较快,较高的光合速率、根系活力和生理代谢物质含量,缓解了低氧胁迫对幼苗的伤害。     

Steam radish sprout (Raphanus sativus L.): active substances,antioxidant activities and non-targeted metabolomics analysis

Various active substances, antioxidant activities and primary differential metabolite profiles were investigated to assess the nutritional quality of radish sprouts steamed for 0–300 s. The levels of flavonoids, total phenolic content and isothiocyanate in radish sprouts decreased with increased steaming time, and DPPH radical scavenging activity levels and superoxide dismutase levels also exhibited a downward trend (P < 0.05). By contrast, total phenolic acid, ferric-reducing antioxidant power and reducing power levels exhibited significant increases in the early short-term steaming process (P < 0.05). Steaming for 30 s promoted the accumulation of vitamin B₂, whereas, steaming for 300 s promoted the accumulation of phospholipids and myristic acid to a greater extent than steaming for 30 s. Overall, there was a partial non-decreased nutritional indicator in short-term steaming of radish sprouts, and a longer steaming time positively affected the differential metabolites.     

豆腐果苷及其代谢产物时辰药动学研究

目的：研究不同时辰给药对豆腐果苷及其代谢产物药代动力学行为的影响。方法：建立并验证豆腐果苷及其3种Ⅰ相代谢产物高效液相色谱-质谱联用同时检测方法。分别在8∶00,14∶00及0∶00灌胃给予大鼠豆腐果苷50 mg/kg,眼底静脉丛采集血样,测得其血药浓度,对比在不同时间给药后原药及代谢产物的药物代谢动力学行为。结果：所建立的高效液相色谱串联质谱检测方法成功应用于灌胃给药后的大鼠血浆豆腐果苷及其3种代谢产物的同时检测。以AUC(0-t)做为吸收程度评价指标,原药、氧化产物、还原产物均为8∶00给药组>0∶00给药组>14∶00给药组;同一时间点原药与代谢产物比较,8∶00给药组、14∶00给药组、0∶00给药组均为：原药>还原产物>氧化产物。Cmax原药0∶00给药组>8∶00给药组>14∶00给药组,还原产物与氧化产物为8∶00给药组>14∶00给药组>0∶00给药组;Tmax原药与还原产物8∶00给药组>14∶00给药组>0∶00给药组,氧化产物8∶00给药组>0∶00给药组>14∶00给药组;以CLz/F为表征的清除情况,原药、还原产物与氧化产物均为14∶00给药组>0∶00给药组>8∶00给药组。 结论：本研究所选择的三个特定时间点,大鼠体内豆腐果苷原药及代谢产物在吸收与代谢过程显示出明显差异。8∶00给药吸收程度要大于其他两个时间点（P<0.01）,14∶00给药原药及代谢产物体内清除快于其他时间点（P<0.01）。