Kulshreshtha Garima, Borza Tudor, Rathgeber Bruce, Stratton Glenn S, Thomas Nikhil A, Critchley Alan, Hafting Jeff, Prithiviraj Balakrishnan
Department of Environmental Sciences, Faculty of Agriculture, Dalhousie UniversityTruro, NS, Canada; Acadian Seaplants LimitedDartmouth, NS, Canada.
Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada.
Front Microbiol. 2016 Mar 31;7:421. doi: 10.3389/fmicb.2016.00421. eCollection 2016.
Red seaweeds are a rich source of unique bioactive compounds and secondary metabolites that are known to improve human and animal health. S. Enteritidis is a broad range host pathogen, which contaminates chicken and poultry products that end into the human food chain. Worldwide, Salmonella outbreaks have become an important economic and public health concern. Moreover, the development of resistance in Salmonella serovars toward multiple drugs highlights the need for alternative control strategies. This study evaluated the antimicrobial property of red seaweeds extracts against Salmonella Enteritidis using the Caenorhabditis elegans infection model. Six red seaweed species were tested for their antimicrobial activity against S. Enteritidis and two, Sarcodiotheca gaudichaudii (SG) and Chondrus crispus (CC), were found to exhibit such properties. Spread plate assay revealed that SG and CC (1%, w/v) significantly reduced the growth of S. Enteritidis. Seaweed water extracts (SWE) of SG and CC, at concentrations from 0.4 to 2 mg/ml, significantly reduced the growth of S. Enteritidis (log CFU 4.5-5.3 and log 5.7-6.0, respectively). However, methanolic extracts of CC and SG did not affect the growth of S. Enteritidis. Addition of SWE (0.2 mg/ml, CC and SG) significantly decreased biofilm formation and reduced the motility of S. Enteritidis. Quantitative real-time PCR analyses showed that SWE (CC and SG) suppressed the expression of quorum sensing gene sdiA and of Salmonella Pathogenesis Island-1 (SPI-1) associated genes sipA and invF, indicating that SWE might reduce the invasion of S. Enteritidis in the host by attenuating virulence factors. Furthermore, CC and SG water extracts significantly improved the survival of infected C. elegans by impairing the ability of S. Enteritidis to colonize the digestive tract of the nematode and by enhancing the expression of C. elegans immune responsive genes. As the innate immune response pathways of C. elegans and mammals show a high degree of conservation, these results suggest that these SWE may also impart beneficial effects on animal and human health.
红海藻是独特生物活性化合物和次生代谢产物的丰富来源,已知这些物质可改善人类和动物健康。肠炎沙门氏菌是一种广泛宿主病原体,它会污染进入人类食物链的鸡肉和家禽产品。在全球范围内,沙门氏菌疫情已成为重要的经济和公共卫生问题。此外,沙门氏菌血清型对多种药物产生耐药性的情况凸显了需要替代控制策略。本研究使用秀丽隐杆线虫感染模型评估了红海藻提取物对肠炎沙门氏菌的抗菌特性。测试了六种红海藻物种对肠炎沙门氏菌的抗菌活性,发现其中两种,即高迪肉叶藻(SG)和皱波角叉菜(CC)具有这种特性。平板涂布试验表明,SG和CC(1%,w/v)显著降低了肠炎沙门氏菌的生长。SG和CC的海藻水提取物(SWE),浓度为0.4至2mg/ml时,显著降低了肠炎沙门氏菌的生长(分别为log CFU 4.5 - 5.3和log 5.7 - 6.0)。然而,CC和SG的甲醇提取物对肠炎沙门氏菌的生长没有影响。添加SWE(0.2mg/ml,CC和SG)显著减少了生物膜形成并降低了肠炎沙门氏菌的运动性。定量实时PCR分析表明,SWE(CC和SG)抑制了群体感应基因sdiA以及与沙门氏菌致病岛-1(SPI-1)相关基因sipA和invF的表达,表明SWE可能通过减弱毒力因子来减少肠炎沙门氏菌在宿主中的侵袭。此外,CC和SG水提取物通过损害肠炎沙门氏菌在秀丽隐杆线虫消化道定殖的能力以及增强秀丽隐杆线虫免疫反应基因的表达,显著提高了感染秀丽隐杆线虫的存活率。由于秀丽隐杆线虫和哺乳动物的先天免疫反应途径具有高度保守性,这些结果表明这些SWE可能也会对动物和人类健康产生有益影响。