scholarly journals The synergistic antimicrobial effects of novel bombinin and bombinin H peptides from the skin secretion of Bombina orientalis

2017 ◽  
Vol 37 (5) ◽  
Author(s):  
Jie Xiang ◽  
Mei Zhou ◽  
Yuxin Wu ◽  
Tianbao Chen ◽  
Chris Shaw ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Mammalian Cells ◽  
Functional Characterization ◽  
Multidrug Resistant ◽  
Skin Secretion ◽  
Helical Structures ◽  
Bombina Orientalis ◽  
Biosynthetic Precursor ◽  
Wide Range

Bombinin and bombinin H are two antimicrobial peptide (AMP) families initially discovered from the skin secretion of Bombina that share the same biosynthetic precursor-encoding cDNAs, but have different structures and physicochemical properties. Insight into their possible existing relationship lead us to perform the combination investigations into their anti-infectious activities. In this work, we report the molecular cloning and functional characterization of two novel AMPs belonging to bombinin and bombinin H families from secretions of Bombina orientalis. Their mature peptides (BHL-bombinin and bombinin HL), coded by single ORF, were chemically synthesized along with an analogue peptide that replaced L-leucine with D-leucine from the second position of the N-terminus (bombinin HD). CD analysis revealed that all of them displayed well-defined α-helical structures in membrane mimicking environments. Furthermore, BHL-bombinin displayed broad-spectrum bactericidal activities on a wide range of microorganisms, while bombinin H only exhibited a mildly bacteriostatic effect on the Gram-positive bacteria Staphylococcus aureus. The combination potency of BHL-bombinin with either bombinin HL or bombinin HD showed the synergistic inhibition activities against S. aureus (fractional inhibitory concentration index (FICI): 0.375). A synergistic effect has also been observed between bombinin H and ampicillin, which was further systematically evaluated and confirmed by in vitro time-killing investigations. Haemolytic and cytotoxic examinations exhibited a highly synergistic selectivity and low cytotoxicity on mammalian cells of these three peptides. Taken together, the discovery of the potent synergistic effect of AMPs in a single biosynthetic precursor with superior functional selectivity provides a promising strategy to combat multidrug-resistant pathogens in clinical therapy.

scholarly journals In Vitro Antibacterial Activity of Selected Palestinian Medicinal Plants against Chlamydia trachomatis

2021 ◽  
Vol 12 (3) ◽  
pp. 656-662
Author(s):  
Omar Hamarsheh ◽  
Ahmad Amro ◽  
Munir A. Al-Zeer
Keyword(s):  
Plant Extracts ◽  
Bacterial Resistance ◽  
Multidrug Resistant ◽  
World Health ◽  
Chlamydia Infection ◽  
Drug Candidates ◽  
Cell Defense ◽  
Wide Range ◽  
Alternative Drug

Chlamydia spp. are intracellular pathogens of humans and animals that cause a wide range of diseases such as blinding trachoma and sexually transmitted infections. According to the World Health Organization (WHO), there are more than 127 million new infections each year worldwide. Chlamydial urogenital infections can cause cervicitis, urethritis, pelvic inflammatory disease and infertility. From within an intracellular niche, termed an inclusion, the Chlamydiae complete their life cycle shielded from host defenses. The host cell defense response used to eliminate the pathogen must subvert this protective shield and is thought to involve the gamma interferon-inducible family of immunity related GTPase proteins and nitric oxide. Typically, azithromycin and doxycycline are the first line drugs for the treatment of chlamydial infections. Although C. trachomatis is sensitive to these antibiotics in vitro, currently, there is increasing bacterial resistance to antibiotics including multidrug-resistant C. trachomatis, which have been described in many instances. Therefore, alternative drug candidates against Chlamydia should be assessed in vitro. In this study, we tested and quantified the activity of plant extracts against Chlamydia-infected HeLa cells with C. trachomatis inclusions. The in vitro results show that post-treatment with Artemisia inculta Delile extract significantly inhibits Chlamydia infection compared to DMSO-treated samples. In conclusion, plant extracts may contain active ingredients with antichlamydial activity potential and can be used as alternative drug candidates for treatment of Chlamydia infection which has significant socio-economic and medical impact.

scholarly journals Essential Oil from Origanum vulgare Completely Inhibits the Growth of Multidrug-Resistant Cystic Fibrosis Pathogens

2016 ◽  
Vol 11 (6) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Giovanna Pesavento ◽  
Valentina Maggini ◽  
Isabel Maida ◽  
Antonella Lo Nostro ◽  
Carmela Calonico ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Essential Oil ◽  
Multidrug Resistant ◽  
Diffusion Method ◽  
Achromobacter Xylosoxidans ◽  
Bacterial Strains ◽  
Origanum Vulgare ◽  
Disk Diffusion Method ◽  
Wide Range

Essential oils (EOs) are known to inhibit the growth of a wide range of microorganisms. Particularly interesting is the possible use of EOs to treat multidrug-resistant cystic fibrosis (CF) pathogens. We tested the essential oil (EO) from Origanum vulgare for in vitro antimicrobial activity, against three of the major human opportunistic pathogens responsible for respiratory infections in CF patients; these are methicillin-resistant Staphylococcus aureus, Stenotrophomonas maltophilia and Achromobacter xylosoxidans. Antibiotic susceptibility of each strain was previously tested by the standard disk diffusion method. Most strains were resistant to multiple antibiotics and could be defined as multi-drug-resistant (MDR). The antibacterial activity of O. vulgare EO (OEO) against a panel of 59 bacterial strains was evaluated, with MIC and MBC determined at 24, 48 and 72 hours by a microdilution method. The OEO was effective against all tested strains, although to a different extent. The MBC and MIC of OEO for S. aureus strains were either lower or equal to 0.50%, v/v, for A. xylosoxidans strains were lower or equal to 1% and 0.50%, v/v, respectively; and for S. maltophilia strains were lower or equal to 0.25%, v/v. The results from this study suggest that OEO might exert a role as an antimicrobial in the treatment of CF infections.

scholarly journals Volatile Oils ofNepeta tenuifolia(Jing Jie) as an Alternative Medicine against Multidrug-Resistant Pathogenic Microbes

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Yi-Hsuan Lee ◽  
Chao-Min Wang ◽  
Po-Yu Liu ◽  
Ching-Chang Cheng ◽  
Zong-Yen Wu ◽  
...  
Keyword(s):  
Essential Oils ◽  
In Vitro Study ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Gram Negative ◽  
E Coli ◽  
Wide Range ◽  
Main Component ◽  
Reference Strains

Essential oils from the dried spikes ofNepeta tenuifolia(Benth) are obtained by steam distillation. Pulegone was identified as the main component in the spikes ofN. tenuifoliathrough analysis, with greater than 85% purity obtained in this study. The essential oils are extremely active against all Gram-positive and some Gram-negative reference bacteria, particularlySalmonella enterica,Citrobacter freundii, andEscherichia coli. The minimum inhibitory concentration was found to be between 0.08 and 0.78% (againstS. enterica), 0.39 and 0.78% (againstC. freundii), and 0.097 and 0.39% (againstE. coli), whereas the minimum bactericidal concentration varied in range from 0.097% to 1.04%. In general, the essential oils show a strong inhibitory action against all tested reference strains and clinical isolates. However, the antibacterial activity of EOs against bothPseudomonas aeruginosareference strains and clinical isolates was relatively lower than other Gram-negative pathogens. The essential oils ofN. tenuifoliaalso displayed bactericidal activities (MBC/MIC < 4) in this study. These findings reflect the bactericidal activity of the essential oils against a wide range of multidrug-resistant clinical pathogens in an in vitro study. In addition, we propose the fragmentation pathways of pulegone and its derivatives by LC-ESI-MS/MS in this study.

scholarly journals Achieving tight control of a photoactivatable Cre recombinase gene switch: new design strategies and functional characterization in mammalian cells and rodent

2019 ◽  
Vol 47 (17) ◽  
pp. e97-e97 ◽  
Author(s):  
Kyle Meador ◽  
Christina L Wysoczynski ◽  
Aaron J Norris ◽  
Jason Aoto ◽  
Michael R Bruchas ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Cultured Cells ◽  
Functional Characterization ◽  
Cre Recombinase ◽  
Common Mechanism ◽  
Protein Fragments ◽  
Low Background ◽  
Wide Range ◽  
Split Protein

AbstractA common mechanism for inducibly controlling protein function relies on reconstitution of split protein fragments using chemical or light-induced dimerization domains. A protein is split into fragments that are inactive on their own, but can be reconstituted after dimerization. As many split proteins retain affinity for their complementary half, maintaining low activity in the absence of an inducer remains a challenge. Here, we systematically explore methods to achieve tight regulation of inducible proteins that are effective despite variation in protein expression level. We characterize a previously developed split Cre recombinase (PA-Cre2.0) that is reconstituted upon light-induced CRY2-CIB1 dimerization, in cultured cells and in vivo in rodent brain. In culture, PA-Cre2.0 shows low background and high induced activity over a wide range of expression levels, while in vivo the system also shows low background and sensitive response to brief light inputs. The consistent activity stems from fragment compartmentalization that shifts localization toward the cytosol. Extending this work, we exploit nuclear compartmentalization to generate light-and-chemical regulated versions of Cre recombinase. This work demonstrates in vivo functionality of PA-Cre2.0, describes new approaches to achieve tight inducible control of Cre DNA recombinase, and provides general guidelines for further engineering and application of split protein fragments.

DAPI Method: A Novel Assay to Evaluate the In vitro Impact of Nanomaterials on Mammalian Cells

2006 ◽  
Vol 951 ◽  
Author(s):  
Pavan M. V. Raja ◽  
Jennifer Connolley ◽  
Pulickel M. Ajayan ◽  
Omkaram Nalamasu ◽  
Deanna M. Thompson
Keyword(s):  
Image Analysis ◽  
Mammalian Cells ◽  
Biological Impact ◽  
Simple Estimate ◽  
Aortic Smooth Muscle ◽  
Diphenyltetrazolium Bromide ◽  
Wide Range ◽  
The Impact ◽  
Non Destructive

ABSTRACTThe increasing importance of nanomaterial-related applications has given rise to concerns pertaining to their impact on human health. In vitro mammalian cell-based assays can provide a quick and simple estimate of the possible adverse effects of the nanomaterials. However, recent studies have questioned the efficacy of traditional assays such as the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, in evaluating cell-nanomaterial interactions, implying the need for alternate methods. We applied image analysis to enumerate the DAPI (2-[4-(Aminomethyl) phenyl]-1H-indole-6-carboximidamide, dihydrochloride) – stained cellular nuclei. Image analysis, being non-destructive, capable of automation, and applicable over a wide range of cell seeding densities, offers several advantages compared to older methods like the MTT assay and hemocytometry. Using image analysis, the impact of singlewalled carbon nanotubes (SWNT) on rat aortic smooth muscle cell (SMC) growth kinetics, were examined. Despite the carbon nanomaterial presence, the fluorescent signal from the nuclei was not noticeably impacted over the SWNT range examined (0.00-0.10 mg/ml). We anticipate that this method can also be applied to evaluate the biological impact of other nanomaterials.

scholarly journals Clavanin A Improves Outcome of Complications from Different Bacterial Infections

2014 ◽  
Vol 59 (3) ◽  
pp. 1620-1626 ◽  
Author(s):  
Osmar N. Silva ◽  
Isabel C. M. Fensterseifer ◽  
Elaine A. Rodrigues ◽  
Hortência H. S. Holanda ◽  
Natasha R. F. Novaes ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Bacterial Infections ◽  
Multidrug Resistant ◽  
Toxicity Tests ◽  
Cytotoxic Activities ◽  
Content Type ◽  
Wound Model ◽  
Acute Toxicity Tests

ABSTRACTThe rapid increase in the incidence of multidrug-resistant infections today has led to enormous interest in antimicrobial peptides (AMPs) as suitable compounds for developing unusual antibiotics. In this study, clavanin A, an antimicrobial peptide previously isolated from the marine tunicateStyela clava, was selected as a purposeful molecule that could be used in controlling infection and further synthesized. Clavanin A wasin vitroevaluated againstStaphylococcus aureusandEscherichia colias well as toward L929 mouse fibroblasts and skin primary cells (SPCs). Moreover, this peptide was challenged here in anin vivowound and sepsis model, and the immune response was also analyzed. Despite displaying clearin vitroantimicrobial activity toward Gram-positive and -negative bacteria, clavanin A showed no cytotoxic activities against mammalian cells, and in acute toxicity tests, no adverse reaction was observed at any of the concentrations. Moreover, clavanin A significantly reduced theS. aureusCFU in an experimental wound model. This peptide also reduced the mortality of mice infected withE. coliandS. aureusby 80% compared with that of control animals (treated with phosphate-buffered saline [PBS]): these data suggest that clavanin A prevents the start of sepsis and thereby reduces mortality. These data suggest that clavanin A is an AMP that could improve the development of novel peptide-based strategies for the treatment of wound and sepsis infections.

scholarly journals The Pomegranate: Effects on Bacteria and Viruses That Influence Human Health

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Amy B. Howell ◽  
Doris H. D'Souza
Keyword(s):  
Antimicrobial Activity ◽  
Foodborne Pathogens ◽  
Clinical Results ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Oral Bacteria ◽  
Resistant Bacteria ◽  
Wide Range

Pomegranates have been known for hundreds of years for their multiple health benefits, including antimicrobial activity. The recent surge in multidrug-resistant bacteria and the possibility of widespread global virus pandemics necessitate the need for additional preventative and therapeutic options to conventional drugs. Research indicates that pomegranates and their extracts may serve as natural alternatives due to their potency against a wide range of bacterial and viral pathogens. Nearly every part of the pomegranate plant has been tested for antimicrobial activities, including the fruit juice, peel, arils, flowers, and bark. Many studies have utilized pomegranate peel with success. There are various phytochemical compounds in pomegranate that have demonstrated antimicrobial activity, but most of the studies have found that ellagic acid and larger hydrolyzable tannins, such as punicalagin, have the highest activities. In some cases the combination of the pomegranate constituents offers the most benefit. The positive clinical results on pomegranate and suppression of oral bacteria are intriguing and worthy of further study. Much of the evidence for pomegranates’ antibacterial and antiviral activities against foodborne pathogens and other infectious disease organisms comes fromin vitrocell-based assays, necessitating further confirmation ofin vivoefficacy through human clinical trials.

scholarly journals Synergistic Efficacy of Aedes aegypti Antimicrobial Peptide Cecropin A2 and Tetracycline against Pseudomonas aeruginosa

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Zhaojun Zheng ◽  
Nagendran Tharmalingam ◽  
Qingzhong Liu ◽  
Elamparithi Jayamani ◽  
Wooseong Kim ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Aedes Aegypti ◽  
Mammalian Cells ◽  
Galleria Mellonella ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Synergistic Activity ◽  
Content Type

ABSTRACT The increasing prevalence of antibiotic resistance has created an urgent need for alternative drugs with new mechanisms of action. Antimicrobial peptides (AMPs) are promising candidates that could address the spread of multidrug-resistant bacteria, either alone or in combination with conventional antibiotics. We studied the antimicrobial efficacy and bactericidal mechanism of cecropin A2, a 36-residue α-helical cationic peptide derived from Aedes aegypti cecropin A, focusing on the common pathogen Pseudomonas aeruginosa. The peptide showed little hemolytic activity and toxicity toward mammalian cells, and the MICs against most clinical P. aeruginosa isolates were 32 to 64 μg/ml, and its MICs versus other Gram-negative bacteria were 2 to 32 μg/ml. Importantly, cecropin A2 demonstrated synergistic activity against P. aeruginosa when combined with tetracycline, reducing the MICs of both agents by 8-fold. The combination was also effective in vivo in the P. aeruginosa/Galleria mellonella model (P < 0.001). We found that cecropin A2 bound to P. aeruginosa lipopolysaccharides, permeabilized the membrane, and interacted with the bacterial genomic DNA, thus facilitating the translocation of tetracycline into the cytoplasm. In summary, the combination of cecropin A2 and tetracycline demonstrated synergistic antibacterial activity against P. aeruginosa in vitro and in vivo, offering an alternative approach for the treatment of P. aeruginosa infections.

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