Elsayed Tarek R, Nour Eman, Hamed Ahmed A, Hassan Ashwak Abdel-Moneim, Elenany Yasser Essam
Department of Agricultural Microbiology, Faculty of Agriculture, Cairo University, Giza, 12613 Egypt.
Faculty of Organic Agriculture, Heliopolis University for Sustainable Development, Cairo, 11785 Egypt.
Indian J Microbiol. 2024 Jun;64(2):671-682. doi: 10.1007/s12088-024-01224-7. Epub 2024 Mar 4.
This work aimed to isolate, and identify Lactic Acid Bacteria LAB from Egyptian immature citrus honey, and characterize their secondary metabolites, as well as determine the antibacterial activities and transcription of virulence genes (stx1, stx2, and eae) influenced by these bacterial secondary metabolites. From twenty hives, twenty immature citrus bee honey samples were taken. Traditional cultural and biochemical testing were used, followed by molecular confirmation. Further, LAB isolates' antibacterial and cytotoxic properties were investigated. 16S rRNA gene sequencing were assessed and, two lactic acid bacterial isolates were identified as Ch and Ch. Both isolates have good antagonistic action against clinical pathogens, with Ch exhibiting the best antibacterial activity against all indicator pathogens examined. When compared to untreated cancer cells, the isolates demonstrated significant cytotoxic activity. Ch and Ch cell viability percentages were 39.5% and 18.76%, respectively. Furthermore, when exposed to Ch metabolites, Shiga-producing (STEC) virulence gene expression was suppressed. To identify bacterial secondary metabolites, a high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOF) approach was developed. Twenty-seven metabolites from diverse chemical classes were discovered in the crude extracts with antibacterial and anticancer characteristics. This is the first thorough investigation on the metabolic profile of LAB isolated from immature Egyptian honey and the findings suggested that isolates or their secondary metabolites could be used in the food sector as medicinal alternatives or as a biocontrol agent.
这项工作旨在从埃及未成熟柑橘蜂蜜中分离和鉴定乳酸菌（LAB），表征其次生代谢产物，以及确定受这些细菌次生代谢产物影响的毒力基因（stx1、stx2和eae）的抗菌活性和转录情况。从20个蜂箱中采集了20份未成熟柑橘蜂蜜样本。采用传统的培养和生化测试，随后进行分子确认。此外，还研究了LAB分离株的抗菌和细胞毒性特性。评估了16S rRNA基因测序，鉴定出两种乳酸菌分离株分别为Ch和Ch。两种分离株对临床病原体均具有良好的拮抗作用，其中Ch对所有检测的指示病原体表现出最佳的抗菌活性。与未处理的癌细胞相比，这些分离株表现出显著的细胞毒性活性。Ch和Ch的细胞活力百分比分别为39.5%和18.76%。此外，当暴露于Ch代谢产物时，产志贺毒素大肠杆菌（STEC）的毒力基因表达受到抑制。为了鉴定细菌次生代谢产物，开发了一种高效液相色谱-四极杆飞行时间质谱（HPLC-QTOF）方法。在粗提物中发现了27种来自不同化学类别的具有抗菌和抗癌特性的代谢产物。这是首次对从埃及未成熟蜂蜜中分离的LAB的代谢谱进行全面研究，研究结果表明，这些分离株或其次生代谢产物可在食品领域用作药用替代品或生物防治剂。
