作者：
Zhou, Min;Li, Xiaofang;Hou, Wenfu;Wang, Hongxun*;Paoli, George C.;...
期刊：
Frontiers in Microbiology,2019年10:ARTN 2265 ISSN：1664-302X
通讯作者：
Wang, Hongxun;Shi, Xianming
作者机构：
[Zhou, Min; Li, Xiaofang; Hou, Wenfu; Wang, Hongxun] Wuhan Polytech Univ, Sch Food Sci & Engn, Wuhan, Hubei, Peoples R China;[Paoli, George C.] ARS, Mol Characterizat Foodborne Pathogens Res Unit, USDA, Eastem Reg Res Ctr,Most Joint Res Ctr Food Safety, Wyndmoor, PA USA;[Shi, Xianming] Shanghai Jiao Tong Univ, State Key Lab Microbial Metab, Sch Agr & Biol, MOST USDA Joint Res Ctr Food Safety, Shanghai, Peoples R China
通讯机构：
[Wang, Hongxun] W;[Shi, Xianming] S;Wuhan Polytech Univ, Sch Food Sci & Engn, Wuhan, Hubei, Peoples R China. Shanghai Jiao Tong Univ, State Key Lab Microbial Metab, Sch Agr & Biol, MOST USDA Joint Res Ctr Food Safety, Shanghai, Peoples R China.
关键词：
MLST;Salmonella;blaCTX-M-15;blaCTX-M-65;class I integrons;qnrB
摘要：
Salmonella is a leading cause of foodborne disease and is often associated with the consumption of foods of animal origin. In this study, sixty-six Salmonella isolates were obtained from 631 raw meat samples purchased at small retail suppliers in Hubei Province, China. The most prevalent Salmonella serotypes were Thompson (18.2%) and Agona (13.6%). Frequent antimicrobial resistance was observed for the sulfonamides (43.9%), tetracycline (43.9%), and the b-lactams amoxicillin and ampicillin (36.4% for each). Interestingly, a high incidence of resistance to cephazolin was observed in strains of the most common serotype, S. Thompson. Class I integrons were found in 27.3% (18/66) of the isolates and five of these integrons contained different gene cassettes (aacA4C-arr-3-dfr2, dfrA12-aadA21, aadA2, dfrA12-aadA2, dfr17-aadA5). Additional antimicrobial resistance genes, including blaTEM-1, blaCTX- M-65, blaCTX- M-15, qnrB, and qnrS, were also identified among these Salmonella isolates. Results of replicon typing and conjugation experiments revealed that an integron with qnrB and blaCTX- M-15 genes was present on incH12 mobile plasmid in S. Thompson strain. Multilocus sequence typing (MLST) analysis revealed 32 sequence types, indicating that these isolates were phenotypically and genetically diverse, among which ST26 (18.2%) and ST541 (12.1%) were the predominant sequence types. The integrons, along with multiple antimicrobial resistance genes on mobile plasmids, are likely contributors to the dissemination of multidrug resistance in Salmonella.
作者机构：
[岳琪琪; 刘文; 孔萍] College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, 430023, China;Fresh Food Engineering and Technology Research Center of Hubei Province, Wuhan, 430023, China;College of Biological and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan, 430023, China;[侯温甫] College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, 430023, China<&wdkj&>Fresh Food Engineering and Technology Research Center of Hubei Province, Wuhan, 430023, China;[王丽梅; 王宏勋] Fresh Food Engineering and Technology Research Center of Hubei Province, Wuhan, 430023, China<&wdkj&>College of Biological and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan, 430023, China
通讯机构：
College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, China
摘要：
Lotus (Nelumbo nucifera Gaertn) is a wetland vegetable famous for its nutritional and medicinal value. Phenolic compounds are secondary metabolites that play important roles in the browning of fresh-cut fruits and vegetables, and chemical constituents are extracted from lotus for medicine due to their high antioxidant activity. Studies have explored in depth the changes in phenolic compounds during browning, while little is known about their synthesis during the formation of lotus rhizome. In this study, transcriptomic analyses of six samples were performed during lotus rhizome formation using a high-throughput tag sequencing technique. About 23 million high-quality reads were generated, and 92.14% of the data was mapped to the reference genome. The samples were divided into two stages, and we identified 23,475 genes in total, 689 of which were involved in the biosynthesis of secondary metabolites. A complex genetic crosstalk-regulated network involved in the biosynthesis of phenolic compounds was found during the development of lotus rhizome, and 25 genes in the phenylpropanoid biosynthesis pathway, 18 genes in the pentose phosphate pathway, and 30 genes in the flavonoid biosynthesis pathway were highly expressed. The expression patterns of key enzymes assigned to the synthesis of phenolic compounds were analyzed. Moreover, several differentially expressed genes required for phenolic compound biosynthesis detected by comparative transcriptomic analysis were verified through qRT-PCR. This work lays a foundation for future studies on the molecular mechanisms of phenolic compound biosynthesis during rhizome formation.
摘要：
Selenium is an essential trace element in human body, and kappa-selenocarrageenan (Se-car) is an organic source of selenium supplement. To further utilize Se-car in food packaging, biotherapy or biosensor, the molecular information of Se-car was characterized here and multi-functional Ag NPs synthesized by Se-car were fabricated. Results of GPC-MALLS, FTIR, potentiometric titration, and intrinsic viscosity showed that Se-car was polymerized by nearly 22 basic units of disaccharide. Sixty-four percentage of sulfated groups (SO42-) in carrageenan was replaced by selenium acid (SeO32-), which belonged to weak acid resulting from a gradually decrease of zeta-potential with acidity process to pH 1.0. Besides, the capacity of biosynthesis silver nanoparticles (Ag NPs) by Se-car was studied and it made a comparison with kappa-carrageenan. Results exhibited that Se-car could serve as an efficient reducing and capping agent for Ag NPs fabrication (remarked as Se-car@Ag). The k(app) of Se-car@Ag NPs for catalyzing 4-NP degradation was 2.14 x 10(-2) s(-1). Antibacterial test revealed Se-car@Ag had an ability to inhibit the growth of Escherichia coli and Staphylococcus aureus. To combine the selenium health benefit and functional metal nanoparticles, Se-car@Ag might have potential applications in multiple areas like medicine, disease diagnostic, and drug delivery. (C) 2019 Elsevier B.V. All rights reserved.
作者机构：
[欧阳何一; 韩千慧; 侯温甫; 周敏; 吴忌] College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, 430023, China;[王宏勋] School of Biological and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan, 430023, China;[侯温甫; 王宏勋; 周敏] Fresh Food Engineering and Technology Research Center of Hubei Province, Wuhan, 430023, China
作者机构：
[谢君; 艾有伟; 闵婷] College of Food Science & Engineering, Wuhan Polytechnic University, Wuhan, 430023, China;[代钰] Wuhan Institute Food and Cosmetic Control, Wuhan, 430023, China;Hubei Province Fresh Food Engineering Research Center, Wuhan, 430023, China;[王宏勋; 易阳; 侯温甫] College of Food Science & Engineering, Wuhan Polytechnic University, Wuhan, 430023, China<&wdkj&>Hubei Province Fresh Food Engineering Research Center, Wuhan, 430023, China
通讯机构：
College of Food Science & Engineering, Wuhan Polytechnic University, Wuhan, China
摘要：
Lotus root (Nelumbo nucifera G.) is an important aquatic vegetable in China. Browning easily during the processing and storage reduces the value of lotus root. Therefore, browning is an important issue for the lotus root industry. PAL, PPO and POD genes were reported as being involved in fruit and vegetable tissue browning, and PAL, PPO and POD enzymes have long been associated with lotus root browning. However, the molecular mechanism of PAL, PPO and POD involved in fresh-cut lotus root browning is poorly understood. This paper analyses the effect of different temperatures on the phenolic content, browning, PPO, PAL and POD enzyme activity and the expression pattern of PPO, PAL and POD genes in fresh-cut lotus root. The results show that the change of PAL, PPO and POD enzymatic activity occurs in parallel with the increase in browning degree in storage at different temperatures. Furthermore, the total phenol content and PAL enzyme activity changes are basically identical, suggesting that PAL might be the key genes involved in the synthesis of total phenol content. Two NnPAL, 2 NnPPO and 7 NnPOD genes were isolated using RNA-seq, and the upregulation of NnPAL1, NnPPOA, NnPOD1, NnPOD2, NnPOD3, NnPOD4, NnPOD5 and NnPOD6 by high temperature coincided with the increase in related enzyme activities and the browning degree of fresh-cut lotus root, which should be considered the most important candidates for fresh-cut lotus root browning. (C) 2016 Published by Elsevier B. V.
