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991.
Abstract: Mints (Mentha spp.), aromatic crops grown largely for their essential oils, also are rich sources of nonvolatile antiinflammatory agents. Identification and quantitation of the constituents responsible for their antiinflammatory activity is challenging owing to the lack of suitable chromatographic methodology. In the present research, the simultaneous quantitation of antiinflammatory constituents rosmarinic acid, oleanolic acid, and ursolic acid in mints was attained by using a unique tandem HPLC column system coupled with an electrospray ionization mass detection (MRM mode). The ion mode optimization for rosmarinic acid under negative and triterpenoid acids under positive was achieved by setting 2 time segments in a single run where the polarity mode was switched from negative (0 to 10 min) to positive (10 to 40 min). For the investigated concentration ranges of antiinflammatory agents in mints, good linearities (r2≥ 0.998) were obtained for each calibration curve. Validation of precision and accuracy for this method showed that intra‐ and inter‐day repeatabilities for all analytes were less than 5.51%, and the recoveries varied from 97.8% to 99.3%. The developed LC/MS/MS assay provides a suitable quality control method for the determination of antiinflammatory constituents in Mentha spp. There is a wide range of diversity in the natural product composition for these acids across the Mentha germplasm collection evaluated. The presence of these antiinflammatory acids in post‐distilled mints shows that value‐added nutraceutical enriched products can be developed with proper processing and recovery systems in addition to the distillation and capture of the valuable volatile essential oils. Practical Application: Results from this research would benefit both commercial farmers growing mint for essential oil and those in the food industry where value‐added phytopharmaceutical enriched products can be developed with proper processing, quality control, and recovery systems during mint essential oil distillation. 相似文献
992.
Kuroda M Notaguchi E Sato A Yoshioka M Hasegawa A Kagami T Narita T Yamashita M Sei K Soda S Ike M 《Journal of Bioscience and Bioengineering》2011,112(3):259-264
Pseudomonas stutzeri strain NT-I was isolated from the drainage wastewater of a selenium refinery plant. This bacterium efficiently reduced selenate to elemental selenium without prolonged accumulation of selenite under aerobic conditions. Strain NT-I was able to reduce selenate completely at high concentrations (up to 10 mM) and selenite almost completely (up to 9 mM). In addition, higher concentrations of selenate and selenite were substantially reduced. Activity was observed under the following experimental conditions: 20–50°C, pH 7–9, and 0.05–20 g L–1 NaCl for selenate reduction, and 20–50°C, pH 6–9, and 0.05–50 g L–1 NaCl for selenite reduction. Under anaerobic conditions, selenate was reduced more rapidly, whereas selenite was not reduced at all. The high selenate- and selenite-reducing capability at high concentrations suggested that strain NT-I is suitable for the removal of selenium from high-strength industrial wastewater. 相似文献
993.
The biological control of beef spoilage, with a bacteriophage (phage) pool, was evaluated under simulated retail conditions. A pool of seven phages was selected with the potential to lyse 78% of 86 Pseudomonas test strains. Subsequent host range studies with 1023 pseudomonads from three meat species (beef, pork, lamb) and five abattoirs showed that 585 (57.2%) isolates were susceptible to the phage pool. Depending on bacterial origin, bacterial sensitivity to lysis by the phage pool varied from 25 to 72%. When added to ribeye steaks, the phage pool produced a significant reduction in Pseudomonas growth but this was not sufficient to produce any significant effect upon the retail shelf life of beef. The inability of phages to control beef spoilage was not attributed to a loss of phage virulence since sufficient densities (log pfu/cm2 = 5 to 6) of virulent phage could be re-isolated from beef, 14 days after treatment. It was concluded that the efficacy of the current phage pool was limited by a narrow range of specificity. 相似文献
994.
995.
目的:筛选能够降解咖啡碱的细菌,以期在该毒素的生物脱毒中得到应用。方法:以咖啡碱作为唯一碳源和氮源进行咖啡碱降解菌株的初筛,之后将初筛的10 株菌通过液体培养基咖啡碱降解实验最终筛选出降解能力最强的1 株菌。结果:筛选出的HZ-1 菌株在48h 即可将咖啡碱完全降解,对目标菌株细胞形态、生理生化以及16SrDNA 进行鉴定,确定该菌株为Pseudomonas lutea,属于假单胞菌属。结论:利用咖啡碱作为唯一碳源和氮源从土壤中筛选出降解咖啡碱良好的菌株,为脱除咖啡碱提供了微生物菌种,填补了国内空白。 相似文献
996.
气调箱贮藏对鲜切黄瓜品质的影响及对假单胞菌的抑制作用 总被引:2,自引:0,他引:2
鲜切黄瓜在国内外具有很大的消费市场,但在贮藏期间极易受微生物污染而腐败变质。变形假单胞菌是低温贮藏条件下导致鲜切黄瓜腐败的主要微生物之一。该研究以变形假单胞菌为实验菌株,接种至鲜切黄瓜表面后,探讨3%O2、7%CO2气调箱贮藏对菌株生长和侵染情况,对黄瓜细胞壁降解和细胞壁降解引起的生理生化变化的影响。结果表明,与对照组相比,3%O2、7%CO2气调贮藏抑制了变形假单胞菌的生长,保持了细胞壁的完整性,延缓了原果胶的降解,降低了纤维素酶活性,抑制了β-半乳糖苷酶活性的增加和可溶性果胶的产生,从而保持了硬度,延缓了丙二醛含量和相对电导率的增加,维持了鲜切黄瓜的外观和色泽。总之,3%O2、7%CO2气调箱贮藏抑制了由变形假单胞菌导致的鲜切黄瓜细胞壁的降解,延缓了腐败变质。 相似文献
997.
Yan-Chao Chen Wanlei Qiu Weibin Zhang Jingrong Zhang Roushi Chen Fangyi Chen Ke-Jian Wang 《International journal of molecular sciences》2023,24(1)
New antimicrobial agents are urgently needed to address the increasing emergence and dissemination of multidrug-resistant bacteria. In the study, a chemically synthesized truncated peptide containing 22-amino acids derived from a C-type lectin homolog SpCTL6 of Scylla paramamosain was screened and found to exhibit broad-spectrum antimicrobial activity, indicating that it is an antimicrobial peptide (AMP), named Sp-LECin. Sp-LECin possessed the basic characteristics of most cationic AMPs, such as positive charge (+4) and a relatively high hydrophobicity (45%). After treatment with Sp-LECin, the disruption of microbial membrane integrity and even leakage of cellular contents was observed by scanning electron microscopy (SEM). In addition, Sp-LECin could bind lipopolysaccharide (LPS), increase the outer and inner membrane permeability and induce reactive oxygen species (ROS) production, ultimately leading to the death of Pseudomonas aeruginosa. Furthermore, Sp-LECin exhibited potent anti-biofilm activity against P. aeruginosa during both biofilm formation and maturation. Notably, Sp-LECin had no obvious cytotoxicity and could greatly improve the survival of P. aeruginosa-infected zebrafish, by approximately 40% over the control group after 72 h of treatment. This study indicated that Sp-LECin is a promising antibacterial agent with the potential to be used against devastating global pathogen infections such as P. aeruginosa. 相似文献
998.
根据荧光假单胞菌(Pseudomonas fluorescens)促旋酶(gyrase)的B亚单位基因以及金属蛋白酶(apr)基因设计出两对引物,经过反应条件的优化,建立了用于荧光假单胞菌快速检测的双重聚合酶链式反应(PCR)方法,并对该体系进行评价。结果显示,Pseudomonas fluorescens菌株经普通PCR扩增均可见2条特异性条带(384 bp和194 bp),而其它阴性对照菌株PCR扩增均为阴性。基于基因组DNA的双重PCR检测灵敏度为16.9 fg/μL(3~4拷贝/μL),1.8CFU/m L的UHT牛奶样品(250 m L)经增菌24 h后用该双重PCR方法均可检出。本研究建立的双重PCR检测方法具有良好的特异性和灵敏度,能克服乳制品样品基质的干扰,可应用于乳制品中荧光假单胞菌的快速检测。 相似文献
999.
通过摇瓶培养的方式研究了无机氮源对脱氮假单胞杆菌发酵产维生素B12的代谢调控作用。首先考察了硫酸铵、硝酸铵、硝酸钠、磷酸氢二铵和氯化铵等5种不同无机氮源对脱氮假单胞杆菌代谢过程的影响。结果表明,硫酸铵是维生素B12发酵较为适宜的无机氮源;在此基础上进一步研究了NH4+浓度对脱氮假单胞杆菌发酵过程的影响,结果发现高浓度的NH4+能明显促进菌体的生长,但是会对维生素B12的合成产生一定的负作用;基于此,提出了脱氮假单胞杆菌摇瓶发酵过程的NH4+限制性补加策略,以克服NH4+在菌体生长与维生素B12合成上的矛盾。 相似文献
1000.
以褐藻酸钠为唯一碳源,从海南省红树林、天涯海角、黎安镇及海口等地采集的样品中分离获得4株高产褐藻胶裂解酶的菌株。通过3,5-二硝基水杨酸法监测该4株菌的发酵液酶活随培养时间的变化,结果表明当达到产酶高峰时,菌株E03的发酵液酶活最高(0.58U/mL),菌株S20和W14的发酵液酶活相当(0.230.27U/mL),W13的发酵液酶活稍低(0.13U/mL),但产酶规律呈现明显差异。由菌落形态特征结合16S rDNA系统发育分析,初步确定菌株E03属于假单孢菌属,菌株W14和W13属于弧菌属,而菌株S20属于黄杆菌属。 相似文献