Evaluation of the antimicrobial activities of ultrasonicated spinach leaf extracts using RAPD markers and electron micro
- PDF / 2,366,133 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 59 Downloads / 200 Views
ORIGINAL PAPER
Evaluation of the antimicrobial activities of ultrasonicated spinach leaf extracts using RAPD markers and electron microscopy Ammar Altemimi1,2 · Naoufal Lakhssassi1 · Amer Abu‑Ghazaleh3 · David A. Lightfoot1
Received: 5 May 2017 / Revised: 20 July 2017 / Accepted: 27 July 2017 © Springer-Verlag GmbH Germany 2017
Abstract Spinach (Spinacia oleracea L.) leaves represent an important dietary source of nutrients, antioxidants and antimicrobials. As such, spinach leaves play an important role in health and have been used in the treatment of human diseases since ancient times. Here, the aims were to optimize the extraction methods for recovering antimicrobial substances of spinach leaves, determine the minimum inhibitory concentrations (MICs) of the antimicrobial substances against Escherichia coli and Staphylococcus aureus and, finally, evaluate the effects of spinach leaves’ antimicrobials on bacterial DNA using central composite face-centered methods. The effect of the extracts on both Gram-positive and Gram-negative bacterial models was examined by scanning electron microscopy (SEM) and random amplification of polymorphic (bacterial) DNA (RAPD). The optimal extraction conditions were at 45 °C, ultrasound power of 44% and an extraction time of 23 min. The spinach extracts exhibited antimicrobial activities against both bacteria with MICs in the 60–100 mg/ml range. Interestingly, SEM showed that the treated bacterial cells appear damaged with a reduction in cell number. RAPD analysis of Communicated by Erko Stackebrandt. Ammar Altemimi and Naoufal Lakhssassi contributed equally to this work. * Naoufal Lakhssassi [email protected] 1
Department of Plant, Soil and Agricultural Systems, Southern Illinois University, Carbondale, IL 62901, USA
2
Department of Food Science, College of Agriculture, University of Basrah, Al‑Basrah 61004, Iraq
3
Department of Animal Science Food and Nutrition, Southern Illinois University, Carbondale, IL 62901, USA
genomic DNA showed that the number and sizes of amplicons were decreased by treatments. Based on these results, it was inferred that spinach leaf extracts exert bactericidal activities by both inducing mutations in DNA and causing cell wall disruptions. Keywords Spinach · Antimicrobial activity · SEM · RAPD · Ultrasonic extraction · Escherichia coli · Bacterial pathogens · Staphylococcus aureus
Introduction In the past few decades, there has been a significant increase in resistance to antibiotics of many pathogenic bacteria (Chopra et al. 1996). For instance, approximately 90–95% of Staphylococcus aureus strains were reported to be resistant to penicillin (Casal et al. 2005) and around 70–80% were methicillin resistant (Chambers 2001). Most antibiotics face resistance from other bacteria, including strains of Escherichia coli (Diemert 2006). Thus, antibiotics are becoming ineffective to control diseases caused by these bacteria. Antibiotic resistance is a global problem and antibioticresistant bacterial strains are increasingly appearing
Data Loading...
