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111.
The availability of different forages varies across landscapes, but little is known about how proportional consumption of
different foods affects food intake and the use of landscapes. The relative amounts of nutrients and plant secondary metabolites
(PSM) consumed by herbivores may influence forage intake and animal fitness in landscapes dominated by plants with PSM. Our
objective was to determine if the relative availability of nutritious foods that contain PSM affected food preference and
intake by lambs. Lambs in three treatments (eight lambs/treatment) were offered two PSM-containing foods at different relative
availabilities: treatment 1—ad libitum terpene- and 100-g tannin-containing food, treatment 2—ad libitum tannin- and 100-g terpene-containing food, and treatment 3—ad libitum access to both tannin- and terpene-containing foods. We measured intake of individual foods and total intake of PSM-containing
foods during conditioning and a preference test, where animals were offered both PSM-containing foods ad libitum. When lambs were fed 100 g of the tannin-containing food, they ingested more terpene and total PSM (P < 0.05) than when both PSM were offered ad libitum, but limiting terpenes did not affect intake of tannin or total intake of PSM (P > 0.10). During preference tests, all groups preferred tannins over terpenes, but lambs in the treatment fed 100 g of tannin
had a higher preference for terpenes than did lambs in the other two treatments (P < 0.10). These results support the notion that the relative amounts of PSM consumed affects intake and preference for PSM-containing
foods by herbivores. 相似文献
112.
Chemical Defense of the Caribbean Reef Sponge Axinella corrugata Against Predatory Fishes 总被引:2,自引:0,他引:2
Dean M. Wilson Monica Puyana William Fenical Joseph R. Pawlik 《Journal of chemical ecology》1999,25(12):2811-2823
Field and laboratory experiments were performed to investigate the palatability to predatory fishes of organic extracts and purified compounds from the Caribbean reef sponge Axinella corrugata (=Teichaxinella morchella). When incorporated into artificial foods at the same volumetric concentration as found in sponge tissue, crude extracts of the sponge, as well as a butanol-soluble partition of the crude extract, deterred feeding of the Caribbean reef fish Thalassoma bifasciatum in laboratory aquarium assays and deterred feeding of a natural assemblage of fishes in assays performed on reefs where A. corrugata is found. Bioassay-directed fractionation of the butanol-soluble partition led to the isolation of a single compound responsible for feeding deterrency, stevensine, a previously described dibrominated alkaloid. The mean concentration of stevensine in A. corrugata, as determined by quantitative NMR analysis, was 19.0 mg/ml (N = 8, SD = 7.2 mg/ml). Stevensine deterred feeding in laboratory aquarium assays at concentrations >2.25 mg/ml, and deterred feeding in field assays at ~12 mg/ml. Stevensine represents another in the oroidin class of brominated pyrrole derivatives that function as chemical defenses of sponges in the families Axinellidae and Agelasidae. 相似文献
113.
以一株费氏丙酸杆菌突变株为出发菌株,通过改变发酵培养基、接种量和初始培养pH值3方面,研究其代谢产物对大肠杆菌和沙门氏菌的抑菌作用,并与山梨酸钾的抑菌作用进行对比。结果表明:3种发酵培养基均对大肠杆菌和沙门氏菌均存在一定的抑制作用,其中以乳酸钠(sodium lactate broth,SLB)培养基发酵时,该菌株代谢产物的抑菌活性分别为25.3 AU/mL和18.3 AU/mL,结果要优于0.1%的山梨酸钾的抑菌活性(21.1 AU/mL和14.1 AU/mL);对于接种量而言,对大肠杆菌和沙门氏菌的抑菌活性最佳的接种量分别为6%和5%,其抑菌活性分别为28.1 AU/mL和18.0 AU/mL,抑菌效果均优于0.1%的山梨酸钾;对于不同培养pH值而言,对大肠杆菌和沙门氏菌的抑菌活性最适初始pH值分别为6.5和6,抑菌活性分别为27.6 AU/mL和14.5 AU/mL,其抑菌效果也优于0.1%的山梨酸钾。所以,选择在适宜条件下发酵所得的丙酸杆菌代谢物,对大肠杆菌和沙门氏菌的抑制效果要优于山梨酸钾。对丙酸杆菌代谢物抑菌作用的研究将为新型天然防腐剂的开发提供依据与试验数据支撑。 相似文献
114.
海藻是海洋中未开发完全的生物新资源,富含各种有利用价值的活性代谢产物。为了确定海藻中次级代谢产物的丰富度,该实验利用化学筛选方法(薄层层析色谱(TLC)、高效液相色谱(HPLC)、气相色谱-质谱(GC-MS))对江篱、刺麒麟菜、异枝麒麟菜、石花菜及小球藻这五株海藻中的次级代谢产物进行初步筛选。结果表明,通过薄层层析色谱和高效液相色谱分析得出江蓠和石花菜显色明显,代谢产物丰富且易于提取分离。通过气相色谱-质谱分析色谱分析得出,石花菜、小球藻的石油醚相成分复杂,未知化合物较多,特别是石花菜和小球藻可以进行重点研究,为后续海藻活性代谢产物研究与应用上的研发提供有力的实验基础。 相似文献
115.
建立一种QuEChERS-高效液相色谱-串联质谱法,快速测定鸡肉中氟虫腈及其3种代谢产物(氟甲腈、氟虫腈砜及氟虫腈亚砜)的方法。鸡肉样品经乙腈分散,DisQuE提取管提取和DisQuE净化管净化后,采用液相色谱-串联质谱定量测定,选择性多反应监测模式检测。在0.5~20ng/mL线性范围内,氟虫腈及其代谢产物的回归方程均呈良好的线性关系,R2>0.999,在添加水平为1.0、5.0、10.0μg/kg时,平均回收率为75.2%~89.9%,相对标准偏差(RSD)为0.8%~9.2%,方法检出限为0.5μg/kg,定量限为1.0μg/kg。该方法简便快捷,灵敏度和准确度均较高,精密度较好,适用于鸡肉中氟虫腈及其代谢产物残留量的检测。 相似文献
116.
Pablo Hernndez‐Alonso Nerea Becerra‐Toms Christopher Papandreou Mnica Bull Marta Guasch‐Ferr Estefanía Toledo Miguel Ruiz‐Canela Clary B. Clish Dolores Corella Courtney Dennis Amy Deik Dong D. Wang Cristina Razquin Jean‐Philippe Drouin‐Chartier Ramon Estruch Emilio Ros Montserrat Fit Fernando Ars Miquel Fiol Lluís Serra‐Majem Liming Liang Miguel A Martínez‐Gonzlez Frank B Hu Jordi Salas‐Salvad 《Molecular nutrition & food research》2020,64(12)
117.
目的建立气相色谱-三重四极杆质谱(gas chromatography-triple quadrupole mass spectrometry,GC-MS/MS)测定糙米中氟虫腈及其代谢产物氟甲腈、氟虫腈砜、氟虫腈硫醚残留的的分析方法。方法糙米加水涡旋混匀后乙腈提取,通过N-丙基乙二胺(primary secondary amine,PSA)、C_(18)粉末、石墨化炭黑(graphitized carbon black,GCB)粉末净化提取液,气相色谱-三重四极杆质谱多重反应离子监测模式(multiple reaction monitoring,MRM)检测,以外标法定量。结果在1~50μg/L范围下,氟虫腈及其代谢物具有良好的线性关系,相关系数(r)均大于0.99,在2、10、20μg/kg 3个添加水平下,氟虫腈及其代谢物的平均回收率为91.6%~109.9%,相对标准偏差(relative standard deviation,RSD)为4.3%~6.3%。氟虫腈及其代谢物在糙米中的定量限为0.2~0.5μg/kg,定量限添加回收率在85.0%~108.0%,RSD为5.9%~6.9%。结论该方法操作简单快速、试剂耗材消耗少、灵敏度高,适用于快速处理大批量糙米中氟虫腈及其代谢产物的残留量检测。 相似文献
118.
119.
Salma Sultan Walid Mottawea JuDong Yeo Riadh Hammami 《International journal of molecular sciences》2021,22(23)
Over the past decade, gut microbiota dysbiosis has been linked to many health disorders; however, the detailed mechanism of this correlation remains unclear. Gut microbiota can communicate with the host through immunological or metabolic signalling. Recently, microbiota-released extracellular vesicles (MEVs) have emerged as significant mediators in the intercellular signalling mechanism that could be an integral part of microbiota-host communications. MEVs are small membrane-bound vesicles that encase a broad spectrum of biologically active compounds (i.e., proteins, mRNA, miRNA, DNA, carbohydrates, and lipids), thus mediating the horizontal transfer of their cargo across intra- and intercellular space. In this study, we provide a comprehensive and in-depth discussion of the biogenesis of microbial-derived EVs, their classification and routes of production, as well as their role in inter-bacterial and inter-kingdom signaling. 相似文献
120.
目的建立超高效液相色谱-电喷雾串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)测定生菜中9种四环素类抗生素及其代谢产物的残留分析方法。方法生菜样品采用EDTA-Mcllvaine缓冲液与乙腈混合溶液提取,HLB固相萃取小柱净化,色谱分离选择ACQUITY UPLC BEH C18色谱柱,以乙腈和0.2%甲酸水溶液为流动相进行梯度洗脱,得到的分离效果较好。质谱采用电喷雾正离子电离、多反应监测模式检测。结果在0.01~0.5 mg/L范围内线性相关系数r2均大于0.99。仪器检出限为1.085~15.780μg/kg,方法的定量限为3.617~42.526μg/kg。在4个添加水平0.01、0.05、0.1和0.5 mg/kg下,除脱水四环素和差向脱水四环素(其回收率40%)外,其余四环素类抗生素及代谢产物在蔬菜中的添加回收率在为63.4%~101.3%,相对标准偏差为2.52%~12.56%。结论该方法灵敏度高,净化效果好,可以用于蔬菜中四环素类抗生素及其代谢产物的残留分析。 相似文献