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.     

涕灭威及其代谢物在苹果和土壤中残留量分析

本文概述了涕灭威及其代谢物在苹果和土壤中残留量的分析方法。样品以丙酮提取，过氧乙酸氧化，二氯甲烷萃取，气谱火焰光度检测器（ＧＣ／ＦＰＤ）测定。涕灭威在土壤和苹果中的最低检测浓度分别为０００４、０００４毫克／公斤，空白样品添加０１～２０毫克／公斤，涕灭威及其代谢物的平均回收率和变异系数分别为８４７～１０９７％及１０～７８％。     

Investigation of the role of diterpenes produced by marine pulmonatesTrimusculus reticulatus andT. conica

The intertidal pulmonate limpetTrimusculus reticulatus, which is found in caves or crevices along the California coast, was previously reported to contain two novel diterpenoids, 6-isovaleroxylabda-8,13-dien-7,15-diol (1) and 2,7-diacetoxy-6-isovaleroxylabda-8,13-dien-15-ol (2). Dissection of the animals prior to extraction revealed that the diterpenoids were concentrated in the mantle, foot, and mucus, but not in the viscera. The presence ofT. reticulatus or its mucus was toxic to veliger larvae of the sabellariid reef-building tube wormPhragmatopoma californica. The major diterpenoid1 was responsible for the observed larvicidal activity. Protection against overgrowth by settling invertebrate larvae is important for the survival of this sessile filter-feeding pulmonate. A related pulmonate,T. conica, which was found in similar intertidal habitats in New Zealand, contained 6-acetoxy-7-isovaleroxylabda-8,13-dien-15-oic acid (3) and 1,7,12,18-tetraacetoxy-cholest-5-en-3-ol (4). The diterpene3 was also localized in the foot, mantle, and mucus ofT. conica but was not larvicidal toP. californica.     

Continuous polymerization of lactam–lactone block copolymers in a twin‐screw extruder

Continuous copolymerizations of ?‐caprolactone with ?‐caprolactam and ω‐lauryl lactam were carried out in a modular intermeshing corotating twin‐screw extruder. Sodium hydride (initiator) and N‐acetyl caprolactam (coinitiator) were used to synthesize lactam–lactone copolymers in a twin‐screw extruder. We consider the variables of feeding order and feed rate of comonomers on the reactive extrusion of lactam–lactone copolymers. It was observed that simultaneous feeding of both monomers with initiator and coinitiator in the first hopper produced a mixture of homopolymers. When we fed the lactam into the first hopper and caprolactone sequentially into the second hopper, we obtained the lactam–caprolactone block copolymers. However, when we fed caprolactone first into the first hopper and the lactam into the second hopper, the extruded product was a mixture of poly(?‐caprolactone) and lactam monomer. We synthesized high molecular weight copolymers of poly(caprolactam‐b‐caprolactone) and poly(lauryl lactam‐b‐caprolactone) with different block lengths by sequential feeding of monomers. The block length of the block copolymer could be adjusted by controlling the feed rate of each monomer during reactive extrusion. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1429–1437, 2003     

反相高效液相色谱法同时测定多种β 内酰胺类抗生素

建立了一种在同一个色谱体系下同时测定生物样品中头孢拉定、头孢氨苄、头孢克洛、氨苄青霉素、阿莫西林等5种临床最常用的β 内酰胺类抗生素的高效液相色谱方法.采用C8色谱柱（Dupout C8柱，300?mm×4.6?mm），以HAC NaAC 缓冲溶液(pH值为3.6) 甲醇 (75∶25 )为流动相，于254?nm处检测，分离并测定了上述5种抗生素.5种抗生素可在20?min内分离，最低检出限可分别达到0.18，0.21，0.12，0.35，0.25?μg/mL.将该法用于血清及尿样中药物含量的测定取得了满意结果.5种药物在血清中的回收率均大于94.6%，而在尿样中回收率均大于88.3%.实验证明该方法操作简便、快速灵敏、准确.     

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。     

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.     

Milk metabolome reveals variations on enteric methane emissions from dairy cows fed a specific inhibitor of the methanogenesis pathway

Metabolome profiling in biological fluids is an interesting approach for exploring markers of methane emissions in ruminants. In this study, a multiplatform metabolomics approach was used for investigating changes in milk metabolic profiles related to methanogenesis in dairy cows. For this purpose, 25 primiparous Holstein cows at similar lactation stage were fed the same diet supplemented with (treated, n = 12) or without (control, n = 13) a specific antimethanogenic additive that reduced enteric methane production by 23% with no changes in intake, milk production, and health status. The study lasted 6 wk, with sampling and measures performed in wk 5 and 6. Milk samples were analyzed using 4 complementary analytical methods, including 2 untargeted (nuclear magnetic resonance and liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometer) and 2 targeted (liquid chromatography-tandem mass spectrometry and gas chromatography coupled to a flame ionization detector) approaches. After filtration, variable selection and normalization data from each analytical platform were then analyzed using multivariate orthogonal partial least square discriminant analysis. All 4 analytical methods were able to differentiate cows from treated and control groups. Overall, 38 discriminant metabolites were identified, which affected 10 metabolic pathways including methane metabolism. Some of these metabolites such as dimethylsulfoxide, dimethylsulfone, and citramalic acid, detected by nuclear magnetic resonance or liquid chromatography-mass spectrometry methods, originated from the rumen microbiota or had a microbial-host animal co-metabolism that could be associated with methanogenesis. Also, discriminant milk fatty acids detected by targeted gas chromatography were mostly of ruminal microbial origin. Other metabolites and metabolic pathways significantly affected were associated with AA metabolism. These findings provide new insight on the potential role of milk metabolites as indicators of enteric methane modifications in dairy cows.     

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）。