A Comparative Study of the Antimicrobial and Structural Properties of Short Peptides and Lipopeptides Containing a Repetitive Motif KLFK

2019 ◽  
Vol 26 (3) ◽  
pp. 192-203
Author(s):  
María Verónica Húmpola ◽  
María Carolina Rey ◽  
Pablo Gabriel Spontón ◽  
Arturo Carlos Simonetta ◽  
Georgina Guadalupe Tonarelli
Keyword(s):  
Antimicrobial Activity ◽  
Secondary Structure ◽  
Mammalian Cells ◽  
Therapeutic Index ◽  
Dilution Method ◽  
Hemolysis Assay ◽  
Improved Stability ◽  
Repetitive Motif ◽  
Bacteria And Fungi ◽  
Α Helix

Background:In the last years, Antimicrobial Peptides (AMPs) and lipopeptides have received attention as promising candidates to treat infections caused by resistant microorganisms. </P><P> Objective: The main objective of this study was to investigate the effect of repetitive KLFK motifs and the attachment of aliphatic acids to the N-terminus of (KLFK)n peptides on therapeutic properties.Methods:Minimal inhibitory concentration against Gram (+) and (-) bacteria and yeast of synthetic compounds were determined by broth microtiter dilution method, and the toxicity was evaluated by hemolysis assay. Membrane-peptide interaction studies were performed with model phospholipid membranes mimicking those of bacterial and mammalian cells by Fluorescence Spectroscopy. The secondary structure in solution and membranes was determined by Circular Dichroism.Results:Our results showed that the resulting compounds have inhibitory activity against bacteria and fungi. The (KLFK)3 peptide showed the highest therapeutic index against bacterial and yeast strains, and the (KLFK)2 peptide conjugated with octanoic acid was the most active against yeasts. All the lipopeptides containing long-chain fatty acids (C14 or longer) were highly hemolytic at low concentrations. The antimicrobial activity of (KLFK)2 and (KLFK)3 lipopeptides was mainly associated with improved stability of the amphipathic secondary structure, which showed high contributions of α-helix in dipalmitoylphosphatidylglycerol (DPPG) vesicles.Conclusion:The repetition of the KLFK sequence and the conjugation with lipid tails allowed obtained compounds with high antimicrobial activity and low toxicity, becoming good candidates for treating infectious diseases.

scholarly journals ANTIMICROBIAL ACTIVITY AND PHYTOCHEMICAL SCREENING OF THE LEAF EXTRACTS OF EUCALYPTUS GLOBULUS

2017 ◽  
pp. 85-89
Author(s):  
Subramanian Abirami ◽  
Kannan Nishanthini ◽  
Mani Poonkothai
Keyword(s):  
Antimicrobial Activity ◽  
Functional Groups ◽  
Eucalyptus Globulus ◽  
Acetone Extract ◽  
Diffusion Method ◽  
Dilution Method ◽  
Phytochemical Analysis ◽  
Phytochemical Screening ◽  
Ft Ir ◽  
Bacteria And Fungi

Objective: To investigate the antimicrobial activity and phytochemical analysis of Eucalyptus globulus leaves.Methods: The antimicrobial activity of the leaves of E. globulus extracted with acetone, ethanol and petroleum ether was studied using well diffusion method against the selected bacterial and fungal isolates. The antimicrobial susceptibility of the bacteria and fungi to various concentrations of the extract was evaluated by the micro broth dilution method. The preliminary phytochemical screening was performed in the acetone extract of E. globulus. The presence of functional groups in the acetone extract of the leaves of E. globulus was determined by Fourier to transform infrared (FT-IR) spectroscopy.Results: Results suggested that the acetone extract exhibited maximum antimicrobial activity against the tested bacteria and fungi when compared with ciprofloxacin and fluconazole respectively (standard antibiotics). Minimum inhibitory concentration (MIC) showed that the wells containing a concentration of 12.5 mg/ml and 6.25 mg/ml of acetone extract inhibited the bacteria and fungi effectively. Phytochemical screening of acetone extract of E. globulus showed the presence of alkaloids, flavonoids, phenols, tannins, quinones, glycosides, steroids, terpenoids and leucoanthocyanides. FT-IR spectral analysis of the leaf extract of E. globulus showed the presence of functional groups such as–OH,-NH, C=O and–COOH.Conclusion: Thus to conclude, different plants and their formulations have been used in ayurveda to cure diseases for several decades. The findings of the study indicate the potential to exploit the leaves of Eucalyptus globulus in the treatment of microbial diseases.

scholarly journals Brevinin-2GHk from Sylvirana guentheri and the Design of Truncated Analogs Exhibiting the Enhancement of Antimicrobial Activity

Antibiotics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 85 ◽  
Author(s):  
Guanzhu Chen ◽  
Yuxi Miao ◽  
Chengbang Ma ◽  
Mei Zhou ◽  
Zhanzhong Shi ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Mammalian Cells ◽  
Structural Changes ◽  
Structural Characteristics ◽  
Helical Conformation ◽  
Skin Secretion ◽  
Mature Peptide ◽  
Diverse Range ◽  
Low Cytotoxicity ◽  
Α Helix

Brevinins are an important antimicrobial peptide (AMP) family discovered in the skin secretions of Ranidae frogs. The members demonstrate a typical C-terminal ranabox, as well as a diverse range of other structural characteristics. In this study, we identified a novel brevinin-2 peptide from the skin secretion of Sylvirana guentheri, via cloning transcripts, and identifying the expressed mature peptide, in the skin secretion. The confirmed amino acid sequence of the mature peptide was designated brevinin-2GHk (BR2GK). Moreover, as a previous study had demonstrated that the N-terminus of brevinin-2 is responsible for exerting antimicrobial activity, we also designed a series of truncated derivatives of BR2GK. The results show that the truncated derivatives exhibit significantly improved antimicrobial activity and cytotoxicity compared to the parent peptide, except a Pro14 substituted analog. The circular dichroism (CD) analysis of this analog revealed that it did not fold into a helical conformation in the presence of either lipopolysaccharides (LPS) or TFE, indicating that position 14 is involved in the formation of the α-helix. Furthermore, three more analogs with the substitutions of Ala, Lys and Arg at the position 14, respectively, revealed the influence on the membrane disruption potency on bacteria and mammalian cells by the structural changes at this position. Overall, the N-terminal 25-mer truncates demonstrated the potent antimicrobial activity with low cytotoxicity.

scholarly journals D-Amino Acid-Containing Lipopeptides Derived from the Lead Peptide BP100 with Activity against Plant Pathogens

2021 ◽  
Vol 22 (12) ◽  
pp. 6631
Author(s):  
Àngel Oliveras ◽  
Luís Moll ◽  
Gerard Riesco-Llach ◽  
Arnau Tolosa-Canudas ◽  
Sergio Gil-Caballero ◽  
...  
Keyword(s):  
Biological Activity ◽  
Amino Acid ◽  
Secondary Structure ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Biological Profile ◽  
High Antimicrobial Activity ◽  
Hydrophobic Chain ◽  
Bacteria And Fungi ◽  
Α Helix

From a previous collection of lipopeptides derived from BP100, we selected 18 sequences in order to improve their biological profile. In particular, analogues containing a D-amino acid at position 4 were designed, prepared, and tested against plant pathogenic bacteria and fungi. The biological activity of these sequences was compared with that of the corresponding parent lipopeptides with all L-amino acids. In addition, the influence of the length of the hydrophobic chain on the biological activity was evaluated. Interestingly, the incorporation of a D-amino acid into lipopeptides bearing a butanoyl or a hexanoyl chain led to less hemolytic sequences and, in general, that were as active or more active than the corresponding all L-lipopeptides. The best lipopeptides were BP475 and BP485, both incorporating a D-Phe at position 4 and a butanoyl group, with MIC values between 0.8 and 6.2 µM, low hemolysis (0 and 24% at 250 µM, respectively), and low phytotoxicity. Characterization by NMR of the secondary structure of BP475 revealed that the D-Phe at position 4 disrupts the α-helix and that residues 6 to 10 are able to fold in an α-helix. This secondary structure would be responsible for the high antimicrobial activity and low hemolysis of this lipopeptide.

Volatile constituents of Dietes bicolor (Iridaceae) and their antimicrobial activity

2015 ◽  
Vol 70 (7-8) ◽  
pp. 217-225 ◽  
Author(s):  
Iriny M. Ayoub ◽  
Fadia S. Youssef ◽  
Mohamed El-Shazly ◽  
Mohamed L. Ashour ◽  
Abdel Nasser B. Singab ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Geotrichum Candidum ◽  
Dilution Method ◽  
Gram Negative Bacteria ◽  
Volatile Oils ◽  
Streptococcus Pneumonia ◽  
Syncephalastrum Racemosum ◽  
Leaf Oil ◽  
Bacteria And Fungi ◽  
Broth Dilution

Abstract Volatile oils from the leaves, flowers and rhizomes of Dietes bicolor (Steud.) Sweet ex Klatt (Iridaceae) were analyzed using GLC/FID and GLC/MS. A total of 84 compounds were identified accounting for 94.65, 95.63 and 87.09% in the hydrodistilled oils from flowers, leaves and rhizomes, respectively. Spathulenol (48.44%) represented the major component in the leaf oil, followed by dihydro-edulan I (6.25%), cubenol (6.00%) and τ-cadinol (5.90%). For the flower and rhizome oils, fatty acids, their esters, aliphatic hydrocarbons and their derivatives predominate. The antimicrobial activity of both leaf and flower oils was investigated against four bacteria in addition to four fungi using the micro-broth dilution method. The leaf oil showed a more potent antimicrobial activity as compared to the flower oil against most of the assessed bacteria and fungi, with higher activities against Gram- positive organisms showing MIC values of 115 and 460 μg/ml for Bacillus subtilis and Streptococcus pneumonia, respectively. Gram-negative bacteria were generally less susceptible (MIC > 2 mg/ml for both oils against Escherichia coli) and being completely ineffective against Pseudomonas aeruginosa. A relevant antifungal potency of the leaf oil against Geotrichum candidum and Syncephalastrum racemosum was also observed with MIC values of 115 and 920 μg/ml, respectively.

scholarly journals Interactions between the plasma membrane and the antimicrobial peptide HP (2-20) and its analogues derived from Helicobacter pylori

2006 ◽  
Vol 394 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Kwang H. Lee ◽  
Dong G. Lee ◽  
Yoonkyung Park ◽  
Dong-Il Kang ◽  
Song Y. Shin ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Helicobacter Pylori ◽  
Membrane Surface ◽  
Helical Structure ◽  
Spin Labels ◽  
Haemolytic Activity ◽  
Bacterial Cells ◽  
New Antibiotics ◽  
Bacteria And Fungi ◽  
Α Helix

HP (2-20), a 19-residue peptide derived from the N-terminus of Helicobacter pylori ribosomal protein L1, has antimicrobial activity but is not cytotoxic to human erythrocytes. We synthesized several peptide analogues to investigate the effects of substitutions on structure and antimicrobial activity. Replacement of Gln16 and Asp18 with tryptophan [anal-3 (analogue-3)] caused a dramatic increase in lytic activities against bacteria and fungi. By contrast, a decrease in amphiphilicity caused by replacement of Phe5 or Leu11 with serine was accompanied by a reduction in antimicrobial activity. Analysis of the tertiary structures of the peptides in SDS micelles by NMR spectroscopy revealed that they have a well-defined α-helical structure. Among the analogues, anal-3 has the longest α-helix, from Val4 to Trp18. The enhanced hydrophobicity and increased α-helicity results in enhanced antimicrobial activity in anal-3 without an increase in haemolytic activity. Fluorescence experiments proved that the bacterial-cell selectivity of the anal-3 peptide is due to its high binding affinity for negatively charged phospholipids in bacterial cells. Results showing the effect of spin-labels on the NMR spectra indicated that the side chains in the hydrophobic phase of the amphiphilic α-helix are buried on the surface of the micelle and the tryptophan indole ring is anchored in the membrane surface. Because anal-3 shows high selectivity towards bacterial and fungal cells, it may provide an avenue for the development of new antibiotics.

Evaluation of antimicrobial potential of some spices from apiaceae sold in herbal shops

2019 ◽  
Author(s):  
Alev ONDER ◽  
Suna Sibel GURPINAR, Mujde ERYILMAZ ◽  
Bayram Kagan AKAY, Ahsen Sevde CINAR
Keyword(s):  
Antimicrobial Activity ◽  
Daucus Carota ◽  
Antimicrobial Effect ◽  
Coriandrum Sativum ◽  
Apium Graveolens ◽  
Dilution Method ◽  
Anethum Graveolens ◽  
Foeniculum Vulgare ◽  
Pimpinella Anisum ◽  
Hexane Extracts

Spices are a part of the plants used for many purposes as preservatives and as colorants in foods or as medicinal intention. Main aim of the present research was to estimate the potential antimicrobial activity of some spices from Apiaceae family such as Amni visnaga (Diş otu, Hıltan), Anethum graveolens (Dereotu), Apium graveolens (Kereviz), Coriandrum sativum (Kişniş), Cuminum cyminum (Kimyon), Daucus carota (Havuç), Foeniculum vulgare (Rezene), Petroselinum sativum (Maydanoz), Pimpinella anisum (Anason). Thus, the fruits of the plants are used in the experiments. The fruits have been extracted by n-hexane, and all extracts have been subjected to TLC (Thin Layer Chromatography). The n-hexane extracts were screened for their potential in vitro antibacterial activity against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 13883, Pseudomonas aeruginosa ATCC 27853 and antifungal activity against Candida albicans ATCC 10231 by microbroth dilution method. The hexane extracts of the fruits of Coriandrum sativum, Anethum graveolens, Daucus carota, and Pimpinella anisum did not show antimicrobial activity against tested microorganisms. Except these, the other extracts having MIC values of 2.5-5-10 mg/mL exhibited antimicrobial effect against some tested microorganisms. These results demonstrate that the extracts which have an antimicrobial effect can probably play a role as an antimicrobial agent owing to their nonpolar components which are accumulated to the n-hexane extracts.

Effect of Temperature and pH on the Secondary Structure and Denaturation Process of Jumbo Squid Hepatopancreas Cathepsin D.

2019 ◽  
Vol 26 (7) ◽  
pp. 532-541 ◽  
Author(s):  
Cadena-Cadena Francisco ◽  
Cárdenas-López José Luis ◽  
Ezquerra-Brauer Josafat Marina ◽  
Cinco-Moroyoqui Francisco Javier ◽  
López-Zavala Alonso Alexis ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Secondary Structure ◽  
Cathepsin D ◽  
Thermal Denaturation ◽  
Protein Denaturation ◽  
Marine Organisms ◽  
Effect Of Temperature ◽  
Jumbo Squid ◽  
Α Helix ◽  
Circular Dichroïsm

Background: Cathepsin D is a lysosomal enzyme that is found in all organisms acting in protein turnover, in humans it is present in some types of carcinomas, and it has a high activity in Parkinson's disease and a low activity in Alzheimer disease. In marine organisms, most of the research has been limited to corroborate the presence of this enzyme. It is known that cathepsin D of some marine organisms has a low thermostability and that it has the ability to have activity at very acidic pH. Cathepsin D of the Jumbo squid (Dosidicus gigas) hepatopancreas was purified and partially characterized. The secondary structure of these enzymes is highly conserved so the role of temperature and pH in the secondary structure and in protein denaturation is of great importance in the study of enzymes. The secondary structure of cathepsin D from jumbo squid hepatopancreas was determined by means of circular dichroism spectroscopy. Objective: In this article, our purpose was to determine the secondary structure of the enzyme and how it is affected by subjecting it to different temperature and pH conditions. Methods: Circular dichroism technique was used to measure the modifications of the secondary structure of cathepsin D when subjected to different treatments. The methodology consisted in dissecting the hepatopancreas of squid and freeze drying it. Then a crude extract was prepared by mixing 1: 1 hepatopancreas with assay buffer, the purification was in two steps; the first step consisted of using an ultrafiltration membrane with a molecular cut of 50 kDa, and the second step, a pepstatin agarose resin was used to purification the enzyme. Once the enzyme was purified, the purity was corroborated with SDS PAGE electrophoresis, isoelectric point and zymogram. Circular dichroism is carried out by placing the sample with a concentration of 0.125 mg / mL in a 3 mL quartz cell. The results were obtained in mdeg (millidegrees) and transformed to mean ellipticity per residue, using 111 g/mol molecular weight/residue as average. Secondary-structure estimation from the far-UV CD spectra was calculated using K2D Dichroweb software. Results: It was found that α helix decreases at temperatures above 50 °C and above pH 4. Heating the enzyme above 70°C maintains a low percentage of α helix and increases β sheet. Far-UV CD measurements of cathepsin D showed irreversible thermal denaturation. The process was strongly dependent on the heating rate, accompanied by a process of oligomerization of the protein that appears when the sample is heated, and maintained a certain time at this temperature. An amount typically between 3 and 4% α helix of their secondary structure remains unchanged. It is consistent with an unfolding process kinetically controlled due to the presence of an irreversible reaction. The secondary structure depends on pH, and a pH above 4 causes α helix structures to be modified. Conclusion: In conclusion, cathepsin D from jumbo squid hepatopancreas showed retaining up to 4% α helix at 80°C. The thermal denaturation of cathepsin D at pH 3.5 is under kinetic control and follows an irreversible model.

scholarly journals Antimicrobial metabolite profiling of Nigrospora sphaerica from Adiantum philippense L.

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Kolathuru Puttamadaiah Ramesha ◽  
Nagabhushana Chandra Mohana ◽  
Bettadapura Rameshgowda Nuthan ◽  
Devaraju Rakshith ◽  
Sreedharamurthy Satish
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Xanthomonas Campestris ◽  
Fungal Endophytes ◽  
Leaf Segment ◽  
Spectroscopic Techniques ◽  
Biological Potential ◽  
Bioassay Guided Fractionation ◽  
Antimicrobial Metabolite ◽  
Bacteria And Fungi

Abstract Background Endophyte bestows beneficial aspects to its inhabiting host, along with a contribution to diverse structural attributes with biological potential. In this regard, antimicrobial profiling of fungal endophytes from medicinal plant Adiantum philippense revealed bioactive Nigrospora sphaerica from the leaf segment. Chemical and biological profiling through TLC–bioautography and hyphenated spectroscopic techniques confirmed the presence of phomalactone as an antimicrobial metabolite. Results The chemical investigation of the broth extract by bioassay-guided fractionation confirmed phomalactone as a bioactive antimicrobial secondary metabolite. The antimicrobial activity of phomalactone was found to be highest against Escherichia coli by disc diffusion assay. The MIC was found to be significant against both Escherichia coli and Xanthomonas campestris in the case of bacteria and dermatophyte Candida albicans at 150 μg/ml, respectively. Conclusions Overall, the results highlighted the antimicrobial potential of phomalactone from the endophyte Nigrospora sphaerica exhibiting a broad spectrum of antimicrobial activity against human and phytopathogenic bacteria and fungi. This work is the first report regarding the antibacterial activity of phomalactone.

scholarly journals Plant antimicrobial peptides: structures, functions, and applications

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.

scholarly journals Evaluation of the Antimicrobial Activity of Some Components of the Essential Oils of Plants Used in the Traditional Medicine of the Tehuacán-Cuicatlán Valley, Puebla, México

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 295
Author(s):  
Sebastián Candelaria-Dueñas ◽  
Rocío Serrano-Parrales ◽  
Marisol Ávila-Romero ◽  
Samuel Meraz-Martínez ◽  
Julieta Orozco-Martínez ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oils ◽  
Qualitative Evaluation ◽  
Bactericidal Effect ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Diffusion Technique ◽  
Agar Dilution

In Tehuacán-Cuicatlán valley (Mexico), studies have been carried out on the essential oils of medicinal plants with antimicrobial activity and it was found that they present compounds in common such as: α-pinene, β-pinene, carvacrol, eugenol, limonene, myrcene, ocimene, cineole, methyl salicylate, farnesene, and thymol. The goal of this study was to assess the antimicrobial activity of essential oils’ compounds. The qualitative evaluation was carried out by the Kirby Baüer agar diffusion technique in Gram-positive bacteria (11 strains), Gram-negative bacteria (18 strains), and yeasts (8 strains). For the determination of the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), the agar dilution method was used. All the evaluated compounds presented antimicrobial activity. The compounds eugenol and carvacrol showed the largest inhibition zones. Regarding yeasts, the compounds ocimene, cineole, and farnesene did not show any activity. The compounds eugenol, carvacrol, and thymol presented the lowest MIC; bactericidal effect was observed at MIC level for S. aureus 75MR, E. coli 128 MR, and C albicans CUSI, for different compounds, eugenol, carvacrol, and thymol. Finally, this study shows that the essential oils of plants used by the population of Tehuacán-Cuicatlán valley share compounds and some of them have antibacterial and fungicidal activity.

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