scholarly journals Cell Membrane-Interrupting Antimicrobial Peptides from Isatis indigotica Fortune Isolated by a Bacillus subtilis Expression System

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 30 ◽  
Author(s):  
Jia Wu ◽  
Hafiz Muhammad Khalid Abbas ◽  
Jiale Li ◽  
Yuan Yuan ◽  
Yunjun Liu ◽  
...  

The situation of drug resistance has become more complicated due to the scarcity of plant resistance genes, and overcoming this challenge is imperative. Isatis indigotica has been used for the treatment of wounds, viral infections, and inflammation for centuries. Antimicrobial peptides (AMPs) are found in all classes of life ranging from prokaryotes to eukaryotes. To identify AMPs, I. indigotica was explored using a novel, sensitive, and high-throughput Bacillus subtilis screening system. We found that IiR515 and IiR915 exhibited significant antimicrobial activities against a variety of bacterial (Xanthomonas oryzae, Ralstonia solanacearum, Clavibacter michiganensis, and C. fangii) and fungal (Phytophthora capsici and Botrytis cinerea) pathogens. Scanning electron microscope and cytometric analysis revealed the possible mechanism of these peptides, which was to target and disrupt the bacterial cell membrane. This model was also supported by membrane fluidity and electrical potential analyses. Hemolytic activity assays revealed that these peptides may act as a potential source for clinical medicine development. In conclusion, the plant-derived novel AMPs IiR515 and IiR915 are effective biocontrol agents and can be used as raw materials in the drug discovery field.

2020 ◽  
Vol 21 (22) ◽  
pp. 8722
Author(s):  
Jiale Li ◽  
Samiul Islam ◽  
Pengfei Guo ◽  
Xiaoqing Hu ◽  
Wubei Dong

Antimicrobial genes are distributed in all forms of life and provide a primary defensive shield due to their unique broad-spectrum resistance activities. To better isolate these genes, we used the Bacillus subtilis expression system as the host cells to build Oryza rufipogon Griff cDNA libraries and screen potential candidate genes from the library at higher flux using built-in indicator bacteria. We observed that the antimicrobial peptides OrR214 and OrR935 have strong antimicrobial activity against a variety of Gram-positive and Gram-negative bacteria, as well as several fungal pathogens. Owing to their high thermal and enzymatic stabilities, these two peptides can also be used as field biocontrol agents. Furthermore, we also found that the peptide OrR214 (MIC 7.7–10.7 μM) can strongly inhibit bacterial growth compared to polymyxin B (MIC 5–25 μM) and OrR935 (MIC 33–44 μM). The cell flow analysis, reactive oxygen burst, and electron microscopy (scanning and transmission electron microscopy) observations showed that the cell membranes were targeted by peptides OrR214 and OrR935, which revealed the mode of action of bacteriostasis. Moreover, the hemolytic activity, toxicity, and salt sensitivity experiments demonstrated that these two peptides might have the potential to be used for clinical applications. Overall, OrR214 and OrR935 antimicrobial peptides have a high-throughput bacteriostatic activity that acts as a new form of antimicrobial agent and can be used as a raw material in the field of drug development.


Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 704 ◽  
Author(s):  
Aslaa Ahmed ◽  
Gavriella Siman-Tov ◽  
Grant Hall ◽  
Nishank Bhalla ◽  
Aarthi Narayanan

Successful in vivo infection following pathogen entry requires the evasion and subversion of multiple immunological barriers. Antimicrobial peptides (AMPs) are one of the first immune pathways upregulated during infection by multiple pathogens, in multiple organs in vivo. In humans, there are many classes of AMPs exhibiting broad antimicrobial activities, with defensins and the human cathelicidin LL-37 being the best studied examples. Whereas historically the efficacy and therapeutic potential of AMPs against bacterial infection has been the primary focus of research, recent studies have begun to elucidate the antiviral properties of AMPs as well as their role in regulation of inflammation and chemoattraction. AMPs as therapeutic tools seem especially promising against emerging infectious viral pathogens for which no approved vaccines or treatments are currently available, such as dengue virus (DENV) and Zika virus (ZIKV). In this review, we summarize recent studies elucidating the efficacy and diverse mechanisms of action of various classes of AMPs against multiple viral pathogens, as well as the potential use of human AMPs in novel antiviral therapeutic strategies.


2009 ◽  
Vol 1 (2) ◽  
Author(s):  
Risa Nofiani ◽  
Siti Nurbetty ◽  
Ajuk Sapar

<p>The increase of issues on the antibiotics resistant pathogenic bacteria has triggered high exploration for new antimicrobial compounds. One of the potential sources is sponge-associated bacteria. The aim of this study was to get sponge-associated bacteria extract containing antimicrobial activities. On the basis screening of antimicrobial activity using by streaking on agar medium, there were two potential isolates with antimicrobial activities namely LCS1 and LCS2. The two isolates were cultivated,then secondary metabolite product were extracted using methanol as a solvent. Minimum inhibitory concentrations (MICs) of extract LCS 1 were 1,000 μg/well for S. aureus, 950 μg/well for Salmonella sp.and 800 μg/well for Bacillus subtilis. Minimum inhibitory concentrations of extract LCS 2 were 500 μg/well for S. aureus, 1,050 μg/well for Salmonella sp., 750 μg/well for Bacillus subtilis, 350 μg/well for P. aeruginosa, 750 μg/sumur terhadap B. subtilis. Based on the MIC values, the two assay extracts have a relatively low antimicrobial activity.</p> <p>Keywords:Antimicrobial,Sponges associated bacteria,MICs</p>


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Paulina D. Rakowska ◽  
Mariavitalia Tiddia ◽  
Nilofar Faruqui ◽  
Claire Bankier ◽  
Yiwen Pei ◽  
...  

AbstractViral infections are a serious health challenge, and the COVID-19 pandemic has increased the demand for antiviral measures and treatments for clean surfaces, especially in public places. Here, we review a range of natural and synthetic surface materials and coatings with antiviral properties, including metals, polymers and biopolymers, graphene and antimicrobial peptides, and their underpinning antiviral mechanisms. We also discuss the physico-chemical properties of surfaces which influence virus attachment and persistence on surfaces. Finally, an overview is given of the current practices and applications of antiviral and virucidal materials and coatings in consumer products, personal protective equipment, healthcare and public settings.


2021 ◽  
Vol 62 (1) ◽  
Author(s):  
Junpeng Li ◽  
Shuping Hu ◽  
Wei Jian ◽  
Chengjian Xie ◽  
Xingyong Yang

AbstractAntimicrobial peptides (AMPs) are a class of short, usually positively charged polypeptides that exist in humans, animals, and plants. Considering the increasing number of drug-resistant pathogens, the antimicrobial activity of AMPs has attracted much attention. AMPs with broad-spectrum antimicrobial activity against many gram-positive bacteria, gram-negative bacteria, and fungi are an important defensive barrier against pathogens for many organisms. With continuing research, many other physiological functions of plant AMPs have been found in addition to their antimicrobial roles, such as regulating plant growth and development and treating many diseases with high efficacy. The potential applicability of plant AMPs in agricultural production, as food additives and disease treatments, has garnered much interest. This review focuses on the types of plant AMPs, their mechanisms of action, the parameters affecting the antimicrobial activities of AMPs, and their potential applications in agricultural production, the food industry, breeding industry, and medical field.


Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 585
Author(s):  
Marie-Louise Heymich ◽  
Laura Nißl ◽  
Dominik Hahn ◽  
Matthias Noll ◽  
Monika Pischetsrieder

The fight against food waste benefits from novel agents inhibiting spoilage. The present study investigated the preservative potential of the antimicrobial peptides Leg1 (RIKTVTSFDLPALRFLKL) and Leg2 (RIKTVTSFDLPALRWLKL) recently identified in chickpea legumin hydrolysates. Checkerboard assays revealed strong additive antimicrobial effects of Leg1/Leg2 with sodium benzoate against Escherichia coli and Bacillus subtilis with fractional inhibitory concentrations of 0.625 and 0.75. Additionally, Leg1/Leg2 displayed antifungal activity with minimum inhibitory concentrations of 500/250 µM against Saccharomyces cerevisiae and 250/125 µM against Zygosaccharomyces bailii. In contrast, no cytotoxic effects were observed against human Caco-2 cells at concentrations below 2000 µM (Leg1) and 1000 µM (Leg2). Particularly Leg2 showed antioxidative activity by radical scavenging and reducing mechanisms (maximally 91.5/86.3% compared to 91.2/94.7% for the control ascorbic acid). The present results demonstrate that Leg1/Leg2 have the potential to be applied as preservatives protecting food and other products against bacterial, fungal and oxidative spoilage.


2014 ◽  
Vol 7 (2) ◽  
pp. 143-151 ◽  
Author(s):  
Y.P. Lei ◽  
L.H. Zhao ◽  
Q.G. Ma ◽  
J.Y. Zhang ◽  
T. Zhou ◽  
...  

Zearalenone (ZEA) and its derivatives are mycotoxins that can cause oestrogenic effects and impair the reproductive physiology of animals, especially in female swine. Strategies to reduce or eliminate ZEA contamination in foods and feeds are very much needed. Among 36 bacterial isolates obtained from a variety of animal intestinal chyme, mouldy foods and feeds, soils, etc., five isolates demonstrated the ability to reduce more than 50% of ZEA in a liquid medium; ANSB01G isolate taken from normal broiler intestinal chyme reduced ZEA the most, by 88.65%. Using physiological, biochemical, and 16S rRNA gene sequence analysis methods, the ANSB01G isolate was identified as Bacillus subtilis. Under simulated intestinal tract conditions, the ANSB01G B. subtilis isolate degraded 84.58, 66.34 and 83.04% of ZEA in naturally contaminated maize, dried distillers’ grains with solubles, and swine complete feed, respectively. The highest degradation of ZEA occurred when the mycotoxin was co-incubated with the whole bacterial culture, resulting in a reduction of 88.65%, followed by 75.60% using culture supernatant, 26.11% using cell extracts, and 15.06% using viable cells. Treatments consisting of both heating and addition of proteinase K significantly reduced the rate of ZEA degradation in the culture supernatant, indicating that the ZEA degradation might be enzymatic. B. subtilis ANSB01G displayed resistance to simulated gastrointestinal tract environments and antimicrobial activities against several common bacterial pathogens, including Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. These properties of B. subtilis ANSB01G suggest the possibility of its potential to effectively degrade ZEA in feed and to develop functional feed products for livestock industries.


2021 ◽  
Vol 50 (2) ◽  
pp. 219-226
Author(s):  
Abdul Haq ◽  
Alam Khan ◽  
Zulfiqar Ali Malik ◽  
Mushtaq Ahmed ◽  
Samiullah Khan ◽  
...  

Antimicrobial activities of deoiled seed kernel (mechanically pressed), fruit coat and seed coat of Jatropha curcas Linn. collected from two regions (Bannu and Peshawar) of Pakistan were investigated. The antimicrobial activities were carried out against Klebsiella pneumoniae (ATCC 43816), Escherichia coli (ATCC 10536), Staphylococcus aureus (ATCC 6538), Bacillus subtilis (ATCC 6633) and two clinical fungal isolates Aspergillus fumigatus and Candida albicans using agar well diffusion method. The antibacterial activities of Peshawar sample were found to be higher than Bannu, against selected strains. While antifungal activities of both samples were similar. Highest zone of inhibition 31.5 ± 0.7 mm was exhibited by n-hexane extract of deoiled seed kernel of Peshawar sample against Bacillus subtilis (ATCC 6633). The minimum inhibitory concentration of ethanolic extracts of deoiled seed kernel and seed coat of Peshawar sample was 31.25 - 25 mg/ml. Whereas, minimum inhibitory concentration of ethanolic and n-hexane extracts of Bannu sample was 62.5 - 125 mg/ml. The results suggested that antimicrobial potential of J. curcas Linn. varied with geographical distribution. The investigation of different varieties of medicinal plants belonging to the same species will greatly enhance the chances of best pharmaceuticals discovery. Bangladesh J. Bot. 50(2): 219-226, 2021 (June)


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