Synthetic Peptides That Exert Antimicrobial Activities in Whole Blood and Blood-Derived Matrices

ABSTRACT Peptides that exert antimicrobial activity in artificial media may lack activity within blood or other complex biological matrices. To facilitate the evaluation of antimicrobial peptides for possible therapeutic utility, an ex vivo assay was developed to assess the extent and durability of peptide antimicrobial activities in complex fluid biomatrices of whole blood, plasma, and serum compared with those in conventional media. Novel antimicrobial peptides (RP-1 and RP-11) were designed based in part on platelet microbicidal proteins. RP-1, RP-11, or gentamicin was introduced into biomatrices either coincident with, or 2 h prior to, inoculation with an Escherichia coli target organism. Antimicrobial activities of peptides were assessed by quantitative culture 2 h after bacterial inoculation and compared to those of peptide-free and gentamicin controls. In whole blood and homologous plasma or serum, introduction of RP-1 or RP-11 coincident with E. coli was associated with a significant reduction in CFU per milliliter versus the respective peptide-free controls. Moreover, substantial antimicrobial activity remained when RP-1 or RP-11 was placed into whole blood or plasma 2 h prior to E. coli inoculation. These results suggest that the peptides were not rapidly inactivated within these biomatrices. Peptide antimicrobial activities were negatively affected by preincubation in serum or in heat-inactivated serum, compared with those of the respective controls. Peptides RP-1 and RP-11 were consistently effective at lower concentrations in biomatrices than in artificial media, indicating favorable antimicrobial interactions with components of blood or blood fractions. Collectively, these findings support the concept that synthetic peptides can be designed to exert potent antimicrobial activities in relevant and complex biological matrices.

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Synergistic Antimicrobial Activities of Combinations of Vanillin and Essential Oils of Cinnamon Bark, Cinnamon Leaves and Cloves

Foods ◽

10.3390/foods10061406 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1406

Author(s):

Rita Cava-Roda ◽

Amaury Taboada-Rodríguez ◽

Antonio López-Gómez ◽

Ginés Benito Martínez-Hernández ◽

Fulgencio Marín-Iniesta

Keyword(s):

Antimicrobial Activity ◽

Essential Oils ◽

Food Packaging ◽

Antimicrobial Effect ◽

Antimicrobial Activities ◽

Inhibitory Effects ◽

Cinnamon Bark ◽

E Coli ◽

Pure Compounds ◽

Main Component

Plant bioactive compounds have antimicrobial and antioxidant activities that allow them to be used as a substitute for synthetic chemical additives in both food and food packaging. To improve its sensory and bactericidal effects, its use in the form of effective combinations has emerged as an interesting possibility in the food industry. In this study, the antimicrobial activities of essential oils (EOs) of cinnamon bark, cinnamon leaves, and clove and the pure compounds vanillin, eugenol, and cinnamaldehyde were investigated individually and in combination against Listeria monocytogenes and Escherichia coli O157:H7. The possible interactions of combinations of pure compounds and EOs were performed by the two-dimensional checkerboard assay and isobologram methods. Vanillin exhibited the lowest antimicrobial activity (MIC of 3002 ppm against L. monocytogenes and 2795 ppm against E. coli O157:H7), while clove and cinnamon bark EOs exhibited the highest antimicrobial activity (402–404 against L. monocytogenes and 778–721 against E. coli O157:H7). For L. monocytogenes, pure compound eugenol, the main component of cinnamon leaves and clove, showed lower antimicrobial activity than EOs, which was attributed to the influence of the minor components of the EOs. The same was observed with cinnamaldehyde, the main component of cinnamon bark EO. The combinations of vanillin/clove EO and vanillin/cinnamon bark EO showed the most synergistic antimicrobial effect. The combination of the EOs of cinnamon bark/clove and cinnamon bark/cinnamon leaves showed additive effect against L. monocytogenes but indifferent effect against E. coli O157:H7. For L. monocytogenes, the best inhibitory effects were achieved by cinnamon bark EO (85 ppm)/vanillin (910 ppm) and clove EO (121 ppm)/vanillin (691 ppm) combinations. For E. coli, the inhibitory effects of clove EO (104 ppm)/vanillin (1006 ppm) and cinnamon leaves EO (118 ppm)/vanillin (979 ppm) combinations were noteworthy. Some of the tested combinations increased the antimicrobial effect and would allow the effective doses to be reduced, thereby offering possible new applications for food and active food packaging.

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Plant antimicrobial peptides: structures, functions, and applications

Botanical Studies ◽

10.1186/s40529-021-00312-x ◽

2021 ◽

Vol 62 (1) ◽

Author(s):

Junpeng Li ◽

Shuping Hu ◽

Wei Jian ◽

Chengjian Xie ◽

Xingyong Yang

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Peptides ◽

Agricultural Production ◽

Food Additives ◽

Antimicrobial Activities ◽

Gram Positive Bacteria ◽

Potential Applications ◽

Potential Applicability ◽

Bacteria And Fungi ◽

Positively Charged

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.

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Therapeutic effects of human mesenchymal stem cell microvesicles in an ex vivo perfused human lung injured with severe E. coli pneumonia

Thorax ◽

10.1136/thoraxjnl-2018-211576 ◽

2018 ◽

Vol 74 (1) ◽

pp. 43-50 ◽

Cited By ~ 48

Author(s):

Jeonghyun Park ◽

Seonguk Kim ◽

Hyungsun Lim ◽

Airan Liu ◽

Shuling Hu ◽

...

Keyword(s):

Antimicrobial Activity ◽

Human Lung ◽

Ex Vivo ◽

Poly I:C ◽

Human Model ◽

Therapeutic Effects ◽

Alveolar Fluid Clearance ◽

Bacterial Killing ◽

E Coli ◽

Protein Permeability

BackgroundWe previously reported that microvesicles (MVs) released by human mesenchymal stem cells (MSC) were as effective as the cells themselves in both Escherichia coli lipopolysaccharide and live bacteria-induced acute lung injury (ALI) mice models. However, it remained unclear whether the biological effect of MSC MV can be applied to human ALI.MethodsIn the current study, we tested the therapeutic effects of MSC MVs in a well-established ex vivo perfused human model of bacterial pneumonia. Using human donor lungs not used for transplantation, we instilled E. coli bacteria intrabronchially and, 1 hour later, administered MSC MVs into the perfusate as therapy.ResultsAfter 6 hours, instillation of E. coli bacteria caused influx of inflammatory cells, which resulted in significant inflammation, lung protein permeability and pulmonary oedema formation. Administration of MSC MV significantly increased alveolar fluid clearance and reduced protein permeability and numerically lowered the bacterial load in the injured alveolus. The beneficial effect on bacterial killing was more pronounced with pretreatment of MSCs with a Toll-like receptor 3 agonist, polyinosinic:polycytidylic acid (Poly (I:C)), prior to the isolation of MVs. Isolated human alveolar macrophages had increased antimicrobial activity with MSC MV treatment in vitro as well. Although oxygenation and lung compliance levels were similar between injury and treatment groups, administration of MSC MVs numerically decreased median pulmonary artery pressure at 6 hours.ConclusionsIn summary, MSC MVs increased alveolar fluid clearance and reduced lung protein permeability, and pretreatment with Poly (I:C) enhanced the antimicrobial activity of MVs in an ex vivo perfused human lung with severe bacteria pneumonia.

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SPS-neutralization in tissue samples for efficacy testing of antimicrobial peptides

BMC Infectious Diseases ◽

10.1186/s12879-019-4700-1 ◽

2019 ◽

Vol 19 (1) ◽

Author(s):

Gabrielle Sherella Dijksteel ◽

Peter H. Nibbering ◽

Magda M. W. Ulrich ◽

Esther Middelkoop ◽

Bouke K. H. L. Boekema

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Peptides ◽

Antimicrobial Agents ◽

Ex Vivo ◽

Residual Activity ◽

Gram Negative Bacteria ◽

Tissue Samples ◽

Gram Negative ◽

Viable Bacteria

Abstract Background Accurate determination of the efficacy of antimicrobial agents requires neutralization of residual antimicrobial activity in the samples before microbiological assessment of the number of surviving bacteria. Sodium polyanethol sulfonate (SPS) is a known neutralizer for the antimicrobial activity of aminoglycosides and polymyxins. In this study, we evaluated the ability of SPS to neutralize residual antimicrobial activity of antimicrobial peptides [SAAP-148 and pexiganan; 1% (wt/v) in PBS], antibiotics [mupirocin (Bactroban) and fusidic acid (Fucidin) in ointments; 2% (wt/wt))] and disinfectants [2% (wt/wt) silver sulfadiazine cream (SSD) and 0.5% (v/v) chlorhexidine in 70% alcohol]. Methods Homogenates of human skin models that had been exposed to various antimicrobial agents for 1 h were pipetted on top of Methicillin-resistant Staphylococcus aureus (MRSA) on agar plates to determine whether the antimicrobial agents display residual activity. To determine the optimal concentration of SPS for neutralization, antimicrobial agents were mixed with PBS or increasing doses of SPS in PBS (0.05–1% wt/v) and then 105 colony forming units (CFU)/mL MRSA were added. After 30 min incubation, the number of viable bacteria was assessed. Next, the in vitro efficacy of SAAP-148 against various gram-positive and gram-negative bacteria was determined using PBS or 0.05% (wt/v) SPS immediately after 30 min incubation of the mixture. Additionally, ex vivo excision wound models were inoculated with 105 CFU MRSA for 1 h and exposed to SAAP-148, pexiganan, chlorhexidine or PBS for 1 h. Subsequently, samples were homogenized in PBS or 0.05% (wt/v) SPS and the number of viable bacteria was assessed. Results All tested antimicrobials displayed residual activity in tissue samples, resulting in a lower recovery of surviving bacteria on agar. SPS concentrations at ≥0.05% (wt/v) were able to neutralize the antimicrobial activity of SAAP-148, pexiganan and chlorhexidine, but not of SSD, Bactroban and Fucidin. Finally, SPS-neutralization in in vitro and ex vivo efficacy tests of SAAP-148, pexiganan and chlorhexidine against gram-positive and gram-negative bacteria resulted in significantly higher numbers of CFU compared to control samples without SPS-neutralization. Conclusions SPS was successfully used to neutralize residual activity of SAAP-148, pexiganan and chlorhexidine and this prevented an overestimation of their efficacy.

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Screening of Antimicrobial Activity and Cytotoxic Effects of Two Cladonia Species

Zeitschrift für Naturforschung C ◽

10.1515/znc-2013-5-604 ◽

2013 ◽

Vol 68 (5-6) ◽

pp. 191-197 ◽

Cited By ~ 2

Author(s):

Birkan Açıkgöz ◽

İskender Karaltı ◽

Melike Ersöz ◽

Zeynep M. Coşkun ◽

Gülşah Çobanoğlu ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Activities ◽

Chloroform Extract ◽

Cytotoxic Effects ◽

Minimal Inhibitory Concentrations ◽

E Coli ◽

Methanol Extracts ◽

Gram Positive Bacteria

The present study explores the antimicrobial activity and cytotoxic effects in culture assays of two fruticose soil lichens, Cladonia rangiformis Hoffm. and Cladonia convoluta (Lamkey) Cout., to contribute to possible pharmacological uses of lichens. In vitro antimicrobial activities of methanol and chloroform extracts against two Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), two Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus), and the yeast Candida albicans were examined using the paper disc method and through determination of minimal inhibitory concentrations (MICs). The data showed the presence of antibiotic substances in the chloroform and the methanol extracts of the lichen species. The chloroform extracts exhibited more signifi cant antimicrobial activity than the methanol extracts. However, a higher antifungal activity was noted in the methanol extract of C. rangiformis. The maximum antimicrobial activity was recorded for the chloroform extract of C. convoluta against E. coli. The cytotoxic effects of the lichen extracts on human breast cancer MCF-7 cells were evaluated by the trypan blue assay yielding IC50 values of ca. 173 and 167 μg/ml for the extracts from C. rangiformis and C. convoluta, respectively.

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Synthetic Peptides Derived from Bovine Lactoferricin Exhibit Antimicrobial Activity against E. coli ATCC 11775, S. maltophilia ATCC 13636 and S. enteritidis ATCC 13076

Molecules ◽

10.3390/molecules22030452 ◽

2017 ◽

Vol 22 (3) ◽

pp. 452 ◽

Cited By ~ 20

Author(s):

Nataly Huertas Méndez ◽

Yerly Vargas Casanova ◽

Anyelith Gómez Chimbi ◽

Edith Hernández ◽

Aura Leal Castro ◽

...

Keyword(s):

Antimicrobial Activity ◽

Synthetic Peptides ◽

E Coli ◽

Bovine Lactoferricin

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Trigona laeviceps Propolis from Thailand: Antimicrobial, Antiproliferative and Cytotoxic Activities

The American Journal of Chinese Medicine ◽

10.1142/s0192415x09007338 ◽

2009 ◽

Vol 37 (05) ◽

pp. 855-865 ◽

Cited By ~ 17

Author(s):

Supawadee Umthong ◽

Songchan Puthong ◽

Chanpen Chanchao

Keyword(s):

Antimicrobial Activity ◽

Methanolic Extract ◽

Water Extract ◽

Antimicrobial Activities ◽

Diffusion Method ◽

Cytotoxic Activities ◽

E Coli ◽

Anticancer Properties ◽

Crude Extracts ◽

Sw620 Cells

Propolis is one of the natural bee products which has long been used as a crude preventative and prophylactic medicine, and has been reported to possess antibacterial, antiviral, anti-inflammatory, antioxidative and anticancer properties. Propolis of the stingless bee, Trigona laeviceps, was extracted by water or methanol at 35% (w/v) yielding a crude water or a methanolic extract at 60 and 80 mg/ml, respectively, which is 17.1 and 22.9% (w/w) of the total propolis, respectively. The antimicrobial activity of both crude extracts was assayed on four selected pathogenic microbes by using the agar well diffusion method. The results suggested that both water and methanolic crude extracts have some antimicrobial activities, water extract has greater antimicrobial activity than methanolic extract. The relative order of sensitivity of the four microbes were, however, the same between the two extracts from the most to least sensitive, S. aureus > E. coli ≫ C. albicans ⋙ A. niger, with indeed no observed growth inhibition of A. niger at all. Antiproliferative and cytotoxic affects were tested on the colon carcinoma cell line, SW620, using the three parameters: (1) MTT assay; (2) cell morphology; and (3) the fragmentation of genomic DNA. The water extract of propolis showed a higher antiproliferative activity than that of methanolic extract to SW620 cells, additionally both appeared to cause cell death by necrosis.

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Synthesis of Plant-Mediated Silver Nanoparticles UsingDioscorea batatasRhizome Extract and Evaluation of Their Antimicrobial Activities

Journal of Nanomaterials ◽

10.1155/2011/573429 ◽

2011 ◽

Vol 2011 ◽

pp. 1-7 ◽

Cited By ~ 24

Author(s):

P. C. Nagajyothi ◽

K. D. Lee

Keyword(s):

Antimicrobial Activity ◽

Silver Nanoparticles ◽

Room Temperature ◽

Antimicrobial Activities ◽

Gram Positive ◽

Gram Negative ◽

Synthesis Of Nanoparticles ◽

E Coli ◽

Synthesize Silver Nanoparticles ◽

Dioscorea Batatas

The eco-friendly synthesis of nanoparticles through various biological means helps to explore various plants for their ability to synthesize silver nanoparticles (AgNPs). Here we have synthesized AgNPs by using rhizome extract ofDioscorea batatasat as well as room temperature (). AgNPs were characterized under UV-vis spectrophotometer, SEM, FTIR, XRD, and EDX. The antimicrobial activity of AgNPs was evaluated on gram positive (B. substilisandS. aureus), gram negative (E. coli), and fungi (S. cerivisaeandC. albicans). At room temperature,S. cerivisaeandC. albicanswere found to be more susceptible to AgNPs than at .

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Whole blood optimization and genetic association of ex vivo TNF-α responsiveness to killed E. coli in Danish Holstein cows

Livestock Science ◽

10.1016/j.livsci.2017.04.014 ◽

2017 ◽

Vol 201 ◽

pp. 92-98

Author(s):

M. Khatun ◽

H.B.H. Jørgensen ◽

A. Ehsani ◽

M.S. Lund ◽

G. Sahana ◽

...

Keyword(s):

Genetic Association ◽

Whole Blood ◽

Ex Vivo ◽

Holstein Cows ◽

E Coli ◽

Tnf Α

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Antimicrobial activity of raw soybean, soybean flour and roasted soybean extracted by ethanol-hexane method

British Food Journal ◽

10.1108/bfj-10-2016-0499 ◽

2017 ◽

Vol 119 (10) ◽

pp. 2277-2286 ◽

Cited By ~ 1

Author(s):

Sireerat Laodheerasiri ◽

Nirasha Horana Pathirage

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Activities ◽

Diffusion Method ◽

Antimicrobial Compounds ◽

Soybean Flour ◽

Hexane Extraction ◽

Disk Diffusion Method ◽

Content Type ◽

E Coli ◽

Inhibitory Compounds

Purpose The purpose of this paper is to determine the antimicrobial compounds extracted from various types of soybean materials; raw soybean, soybean flour and roasted soybean. Bacteria growth inhibition was tested in E.coli and S. aureus by disk diffusion method. Efficiency of antimicrobial activities were compared among the extracted solution. Design/methodology/approach Soybean (Glycine max) isoflavones contain the ability to inhibit the growth of many strains of microorganisms. The solid-liquid extraction, ethanol-hexane extraction, was modified to isolate the inhibitory compounds from the three different types of soybean materials. All crude extracts at various concentrations performed under different extracted solutions (75, 50, 25, 12.5, 6.25 and 3.125 percent) were tested with E. coli. and S. aureus to determine the antimicrobial activities and the minimum inhibition concentration (MIC). Disk diffusion method was chosen to study the antimicrobial activity of isoflavones. Findings Soybean flour extract inhibited the growth of E. coli and S. aureus more effective than roasted soybean and raw soybean, respectively. The MIC of inhibitory compounds extracted from soybean flour was 6.25 percent (0.031 mg/ml), roasted soybean was 25 percent (0.125 mg/ml) and raw soybean was 50 percent (0.250 mg/ml). Crude extracts of soybean flour and roasted soybean showed better results than raw soybean. All the three of extracted soybeans inhibited the growth of E. coli better than S. aureus. Originality/value Ethanol-hexane extraction was successfully used to isolate the antimicrobial compounds from raw soybean, soybean flour and roasted soybean. Comparison of antimicrobial activity showed that soybean flour contained the highest inhibition activity.

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