scholarly journals Replacement of l-Amino Acids by d-Amino Acids in the Antimicrobial Peptide Ranalexin and Its Consequences for Antimicrobial Activity and Biodistribution

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2987 ◽  
Author(s):  
Cornelius Domhan ◽  
Philipp Uhl ◽  
Christian Kleist ◽  
Stefan Zimmermann ◽  
Florian Umstätter ◽  
...  
Keyword(s):  
Amino Acids ◽  
Antimicrobial Activity ◽  
Antimicrobial Peptide ◽  
The Body ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Strong Antimicrobial Activity

Infections caused by multidrug-resistant bacteria are a global emerging problem. New antibiotics that rely on innovative modes of action are urgently needed. Ranalexin is a potent antimicrobial peptide (AMP) produced in the skin of the American bullfrog Rana catesbeiana. Despite strong antimicrobial activity against Gram-positive bacteria, ranalexin shows disadvantages such as poor pharmacokinetics. To tackle these problems, a ranalexin derivative consisting exclusively of d-amino acids (named danalexin) was synthesized and compared to the original ranalexin for its antimicrobial potential and its biodistribution properties in a rat model. Danalexin showed improved biodistribution with an extended retention in the organisms of Wistar rats when compared to ranalexin. While ranalexin is rapidly cleared from the body, danalexin is retained primarily in the kidneys. Remarkably, both peptides showed strong antimicrobial activity against Gram-positive bacteria and Gram-negative bacteria of the genus Acinetobacter with minimum inhibitory concentrations (MICs) between 4 and 16 mg/L (1.9–7.6 µM). Moreover, both peptides showed lower antimicrobial activities with MICs ≥32 mg/L (≥15.2 µM) against further Gram-negative bacteria. The preservation of antimicrobial activity proves that the configuration of the amino acids does not affect the anticipated mechanism of action, namely pore formation.

scholarly journals Antimicrobial Activity and Action Mechanisms of Arg-Rich Short Analog Peptides Designed from the C-Terminal Loop Region of American Oyster Defensin (AOD)

Marine Drugs ◽  
2021 ◽  
Vol 19 (8) ◽  
pp. 451
Author(s):  
Jung-Kil Seo ◽  
Dong-Gyun Kim ◽  
Ji-Eun Lee ◽  
Kwon-Sam Park ◽  
In-Ah Lee ◽  
...  
Keyword(s):  
Amino Acids ◽  
Antimicrobial Activity ◽  
Antimicrobial Agents ◽  
Gram Negative Bacteria ◽  
Significant Activity ◽  
Gram Positive ◽  
American Oyster ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Loop Region

American oyster defensin (AOD) was previously purified from acidified gill extract of the American oyster, Crassostrea virginica. AOD is composed of 38 amino acids with three disulfide bonds and exhibits strong antimicrobial activity against Gram-positive bacteria as well as significant activity against Gram-negative bacteria. Here, to develop promising peptides into antibiotic candidates, we designed five arginine-rich analogs (A0, A1, A2, A3, and A4), predicted their loop and extended strand/random structures—including nine amino acids and a disulfide bond derived from the C-terminus of AOD—and described their antimicrobial and cytotoxic effects, as well as their modes of action. In our experimental results, the A3 and A4 analogs exhibited potent antimicrobial activity against all test organisms—including four Gram-positive bacteria, six Gram-negative bacteria, and Candida albicans—without cell toxicity. A sequence of experiments, including a membrane permeabilization assay, DNA binding study, and DNA polymerization inhibition test, indicated that the two analogs (A3 and A4) possibly did not act directly on the bacterial membrane but instead interacted with intracellular components such as DNA or DNA amplification reactions. AOD analogs also showed strong bacterial inhibition activity in the plasma environment. In addition, analog-treated microbial cells clearly exhibited membrane disruption, damage, and leakage of cytoplasmic contents. Collectively, our results suggest that two analogs, A3 and A4, have potent antimicrobial activity via DNA interaction and have the potential for development into novel antimicrobial agents.

scholarly journals Enaminone-Derived Pyrazoles with Antimicrobial Activity

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Mashooq Ahmad Bhat ◽  
Mohamed A. Al-Omar ◽  
Ahmed M. Naglah ◽  
Abdul Arif Khan
Keyword(s):  
Antimicrobial Activity ◽  
Gram Negative Bacteria ◽  
Significant Activity ◽  
Disc Diffusion ◽  
Initial Screening ◽  
Gram Positive ◽  
Gram Negative ◽  
Disc Diffusion Assay ◽  
Gram Positive Bacteria ◽  
Diffusion Assay

A series of pyrazoles derived from the substituted enaminones were synthesized and were evaluated for antimicrobial activity. All the compounds were characterized by the spectral data and elemental analysis. The synthesized compounds were initially screened for their antimicrobial activity against ATCC 6538, NCTC 10400, NCTC 10418, and ATCC 27853. During initial screening, compounds (P1, P6, and P11) presented significant antimicrobial activity through disc diffusion assay. These compounds were further evaluated for antimicrobial activity at different time points against Gram-positive and Gram-negative bacteria and presented significant activity for 6 hours. The activity was found to be greater against Gram-positive bacteria. In contrast at 24 hours, the activity was found only against Gram-positive bacteria except compound (P11), showing activity against both types of bacteria. Compound (P11) was found to have highest activity against both Gram-positive and Gram-negative bacteria.

Antimicrobial activity of Pycnarrhena cauliflora (Miers.) Diels. methanol extract

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Eti Nurwening Sholikhah ◽  
Maulina Diah ◽  
Mustofa ◽  
Masriani ◽  
Susi Iravati ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Methanolic Extract ◽  
Biological Activities ◽  
Positive Control ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Methanolic Extracts

Pycnarrhena cauliflora (Miers.) Diels., local name sengkubak, is one of indigenous plants from West Kalimantan that has been used as natural flavor. Pycnorrhena cauliflora is one of species of Menispermaceae family which is rich in bisbenzylisoquinoline alkaloids. This alkaloids are known to have various biological activities including antiprotozoal, antiplasmodial, antifungal and antibacterial activities. This study aimed to investigate antimicrobial activity of  the P. cauliflora (Miers.) Diels. methanolic extracts against gram-positive and gram-negative bacteria. The methanolic extract of P. cauliflora (Miers.) Diels., root, leaf and stem were prepared by maceration. The disk-diffusion method was then used to determine the antimicrobial activity of the extracts against Streptococcus pyogenes, S. mutants, Staphylococcus aureus, S. epidermidis, Salmonella typhi, Shigella flexneri, Pseudomonas aeruginosa and Escherichia coli after 18-24 h incubation at 37 oC. Amoxicillin was used as positive control for gram-positive bacteria and ciprofloxacin was used as gram-negative bacteria. The inhibition zones were then measured in mm. Analysis were conducted in duplicates. The results showed in general the methanolic extracts of P. cauliflora (Miers.) Diels. root (inhibition zone diameter= 10-23 mm) were more active than that leaf (0-15 mm) and stem (0-17 mm) extracts against gram-positive bacteria. The zone inhibition diameter of amoxicillin as positive control was 8-42 mm. In addition, the methanolic extracts of P. cauliflora (Miers.) Diels. root (12-17 mm) were also more active than that leaf (0-12 mm) and stem (0-12 mm) extracts against gram-negative bacteria. The zone inhibition diameter of ciprofloxacin as positive control was 33-36 mm. In conclusion, the methanolic extract of P. caulifloria (Miers.) Diels. root is the most extract active against both gram-positive and gram-negative bacteria. Further study will be focused to isolate active compounds in the methanolic extract of the root.

ANTIMICROBIAL ACTIVITY OF COPPER KAOLINITE AND SURFACTANT MODIFIED COPPER KAOLINITE AGAINST GRAM POSITIVE AND GRAM NEGATIVE BACTERIA

2016 ◽  
Vol 78 (3-2) ◽  
Author(s):  
Nor Syafawani Sarah Md Saad ◽  
Nik Ahmad Nizam Nik Malek ◽  
Chun Shiong Chong
Keyword(s):  
Antimicrobial Activity ◽  
Synergistic Effects ◽  
Wide Spectrum ◽  
Copper Nitrate ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray ◽  
Gram Positive Bacteria ◽  
Diffusion Technique

The aim of this research was to determine the antimicrobial activity of kaolinite modified with antimicrobial compounds against Gram positive and Gram negative bacteria. Copper kaolinite (Cu-kaolinite) was prepared by loading raw kaolinite with copper nitrate trihydrate (CuNO3) while surfactant modified Cu-kaolinite (SM-Cu-kaolinite) was prepared by adding cationic surfactants hexadecyltrimethyl ammonium (HDTMA) on Cu-Kaolinite. Samples was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyzer. The antimicrobial activity of the samples was tested against Gram negative bacteria (Escherichia coli ATCC 11229 and Pseudomonas aeruginosa ATCC 15442), and Gram positive bacteria (Staphylococcus aureus ATCC 6538 and Enterococcus faecalis ATCC 29212) through disc diffusion technique (DDT) and minimum inhibition concentration (MIC). The results showed that the antimicrobial activity of Cu-kaolinite increased after modified with HDTMA due to the synergistic effects of Cu ions and HDTMA molecules on the kaolinite. The antimicrobial activity for surfactant modified Cu-kaolinite was greater for Gram positive bacteria compared to Gram negative bacteria. In conclusion, the attachment of HDTMA on Cu-kaolinite contributed to the enhanced antimicrobial activity against wide spectrum of bacteria (Gram positive and Gram negative bacteria).

scholarly journals Increases in Hydrophilicity and Charge on the Polar Face of Alyteserin 1c Helix Change its Selectivity towards Gram-Positive Bacteria

Antibiotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 238 ◽  
Author(s):  
Yamil Liscano ◽  
Constain H. Salamanca ◽  
Lina Vargas ◽  
Stefania Cantor ◽  
Valentina Laverde-Rojas ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Solid Phase ◽  
Structural Characteristics ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Mutant Derivative ◽  
Conventional Antibiotics ◽  
Carboxy Terminal

Recently, resistance of pathogens towards conventional antibiotics has increased, representing a threat to public health globally. As part of the fight against this, studies on alternative antibiotics such as antimicrobial peptides have been performed, and it has been shown that their sequence and structure are closely related to their antimicrobial activity. Against this background, we here evaluated the antibacterial activity of two peptides developed by solid-phase synthesis, Alyteserin 1c (WT) and its mutant derivative (ΔM), which shows increased net charge and reduced hydrophobicity. These structural characteristics were modified as a result of amino acid substitutions on the polar face of the WT helix. The minimum inhibitory concentration (MIC) of both peptides was obtained in Gram-positive and Gram-negative bacteria. The results showed that the rational substitutions of the amino acids increased the activity in Gram-positive bacteria, especially against Staphylococcus aureus, for which the MIC was one-third of that for the WT analog. In contrast to the case for Gram-positive bacteria, these substitutions decreased activity against Gram-negative bacteria, especially in Escherichia coli, for which the MIC was eight-fold higher than that exhibited by the WT peptide. To understand this, models of the peptide behavior upon interacting with membranes of E. coli and S. aureus created using molecular dynamics were studied and it was determined that the helical stability of the peptide is indispensable for antimicrobial activity. The hydrogen bonds between the His20 of the peptides and the phospholipids of the membranes should modulate the selectivity associated with structural stability at the carboxy-terminal region of the peptides.

scholarly journals Evaluation of Antimicrobial Potential of the Marine Cyanobacterium, Rivularia mesenterica

2019 ◽  
pp. 1-11 ◽  
Author(s):  
Mirjana Skočibušić ◽  
Sandra Lacić ◽  
Zorica Rašić
Keyword(s):  
Antimicrobial Activity ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Marine Cyanobacterium ◽  
Gram Positive ◽  
Promising Alternative ◽  
Gram Negative ◽  
Antimicrobial Potential ◽  
Ethanol Extracts ◽  
Promising Source

Background: Antibiotic resistance is becoming a pivotal concern for public health accelerating the search for new antimicrobial molecules from nature. The prevention and treatment of infectious diseases by applying products from marine organisms, especially Cyanobacteria as a potential and promising source of antimicrobial agents appears as a possible alternative. Aims: To evaluate the in vitro antimicrobial potential of different extracts derived from marine cyanobacterium Rivularia mesenterica against Gram-positive and Gram-negative bacteria, including multidrug resistant bacteria, by comparison with clinically relevant antibiotics.   Methodology: The secondary metabolites were extracted from fresh and dried cyanobacterial biomass in water and different organic solvents. Antimicrobial efficacy of different extracts was evaluated by the disc diffusion assay. Additionally, the minimum inhibitory concentrations (MIC) of the ethanol extracts obtained from fresh and dried biomass was also determined. Results: The ethanol extracts obtained from fresh and dried biomass of R. mesenterica showed significant antimicrobial activity against five Gram-positive and five antibiotic resistant Gram-negative bacteria and four fungal strains in comparison with the clinically relevant antibiotics. The inhibitory effect of the ethanol extracts was observed, with MIC values in the range 0.06 to 32.00 μg/ml against tested strains. Furthermore, the water extract was inactive against of the tested bacteria and fungi. Conclusion: These results suggest that the ethanol extracts of R. mesenterica possess potent broad spectrum of antimicrobial activity, which can serve as an interesting source for antimicrobial compounds and promising alternative to synthetic antimicrobial drugs discovery.

scholarly journals Molecular Characterization of Zinc (Zn) Resistant Bacteria in Banger River, Pekalongan, Indonesia

2018 ◽  
Vol 10 (3) ◽  
pp. 622-628
Author(s):  
Fitri Arum Sasi ◽  
Hermin Pancasakti Kusumaningrum ◽  
Anto Budiharjo
Keyword(s):  
Bacterial Species ◽  
Selective Medium ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Indigenous Bacteria ◽  
Gram Positive Bacteria ◽  
Sequences Analysis

Indigenous bacteria are able to remove the metals contamination in environment. This study aimed to assess the resistance of bacterial species to Zinc (Zn) in Banger River, Pekalongan City. The bacteria from three different parts of Banger River were isolated and inoculated in Zn-selective medium. Then, molecular identification to determine the bacteria species was conducted using polymerase chain reaction (PCR) by applying forward-reverse 16SrRNA gene primers. The sequences analysis was conducted using MUSCLE and MEGA6. There were seven dominant species that possibly resistant to Zn. Approximately, every isolate could reach more than 95 % from 2000 ppm of Zn in the medium. The higher absorption of Zn was found in Z5 isolate. The seven bacteria species were clustered into nine genera i.e. Klebsiela, Xenorhabdus, Cronobacter, Enterobacter, Escherichia, Shigella and Sporomusa known as Gram Negative bacteria and Clostridium and Bacillus as Gram Positive bacteria. In Gram Positive bacteria, especially Bacillus sp, carboxyl group in peptidoglycan play a role as metal binder. In Gram-negative bacteria, lipopolysaccharide (LPS) which is highly anionic component on the outer membrane, able to catch the Zn. Besides that, Enterobacter activates endogen antioxidants such as glutathione peroxidase (GSHPx), glutathione reductase (GR), catalase (CAT) and superoxide dismutase (SOD). The research found there was possible seven novel indigenous bacteria species in Banger that able to remove Zn from the sediment extremely. This finding can be developed as an eco-friendly approach to reduce metals pollution using local microorganisms.

Preliminary investigation of antimicrobial activity of the skin secretions of frogs from Bangladesh

2019 ◽  
Vol 40 (4) ◽  
pp. 531-536
Author(s):  
Md. Sirajul Islam ◽  
Md. Mokhlesur Rahman ◽  
Md. Mizanur Rahaman
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Preliminary Investigation ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Hoplobatrachus Tigerinus ◽  
Skin Secretions ◽  
Polypedates Leucomystax

Abstract Amphibians, like some animals and plants, defend themselves against various pathogenic organisms by producing and secreting various peptides and small molecules from granular skin glands. In this study, we evaluated for the first time, the antibiotic activity of the skin secretions of 8 different frog species (Euphlyctis cyanophlyctis, E. hexadactylus, Fejervarya teraiensis, F. asmati, F. syhadrensis, Hoplobatrachus tigerinus, Microhyla ornata and Polypedates leucomystax) from Bangladesh. These secretions were collected by a nonlethal approach through chemical stimulation and the antibacterial activity was evaluated by broth macrodilution method against some Gram-positive and Gram-negative bacteria. Our study revealed that all the skin secretions (8 out of 8) from the selected frogs have antimicrobial activity against Gram-positive bacteria and 7 out of 8 skin secretions possess antibacterial activity against Gram-negative bacteria tested. Further analysis of data showed that these secretions are significantly more effective against Gram-positive bacteria than Gram-negative bacteria.

scholarly journals Antimicrobial Activity of Plant Extracts againstBacillus Subtilis,Staphylococcus Aureusand Escherichia Coli

2011 ◽  
Vol 8 (s1) ◽  
pp. S282-S284 ◽  
Author(s):  
Liliwirianis N ◽  
Wan Zuraida Wan Mohd Zain ◽  
Jamaluddin Kassim ◽  
Shaikh Abdul Karim
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Inhibition Zone ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Stemona Tuberosa ◽  
Elephantopus Scaber

Local herbs have many potential that may be active with antimicrobial activity. A screening was conducted with 11 species of herbs collected in UiTM Pahang Forest Reserve.Epipremnumsp.,Zingibersp.Tetracera indica, Tectaria crenata, Piper stylosum, Homalomena propinque, Goniothalamus sp., Elephantopus scaber, Mapania patiolale, Melastomasp.,Stemona tuberosa, Phullagathis rotundifolia, Thotea grandifoliaandSmilaxsp. were extracted with methanol to obtain their crude. The agar diffusion method using blank disc of 6 mm diameter were loaded with 1000 µg/mL of methanol crude and applied to the inoculate plate was used to assess the antimicrobial activity against two gram positive bacteria (Bacillus subtilisandStaphylococcus aeureus) and one gram negative bacteria (Escherichia coli). The results evaluated as the diameter of the inhibition zone of microbial growth, showed that all the extracts were active against gram-positive bacteria and gram-negative bacteria. The extract ofStemona tuberosewas found to be the most active against theE. coliandS. aeureuswhilePiper stylosumactive againstB. subtilis.

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