Characterization Of Antibacterial Activity Research Articles

Lactic Acid Bacteria Isolated from Cangkuak Riau: Characterization of Antibacterial Activity

Lactic Acid Bacteria Isolated from Cangkuak Riau: Characterization of Antibacterial Activity

Efficient heterologous expression of bovine lactoferrin in Pichia pastoris and characterization of antibacterial activity

Efficient heterologous expression of bovine lactoferrin in Pichia pastoris and characterization of antibacterial activity

Purification and Characterization of Antibacterial Activity against Phytopathogenic Bacteria in Culture Fluids from Ganoderma lucidum.

Previous studies of Ganoderma lucidum have focused on its medicinal applications. Limited information is available about its antibacterial activity against plant pathogens. Thus, the goal of this study was to purify and characterize the antibacterial activity against plant pathogenic bacteria from culture fluids of G. lucidum. The nature of the bioactive components was determined using heat boiling, organic solvents, dialysis tubing, gel exclusion chromatography (GEC), proteinase sensitivity, HPLC, HPLC-APCI-MS, and GC-MS. The bioactive compounds were neither lipid, based on their solubility, nor proteic in nature, based on proteinase digestion and heat stability. The putative-bioactive polysaccharides have molecular weights that range from 3500 to 4500 Daltons as determined by dialysis tubing, GEC and APCI-MS analysis. The composition of the antibacterial compounds was determined by GC-MS. This is the first report of small polysaccharides produced by G. lucidum with activity against bacterial plant pathogens.

Characterization of antibacterial activities and the related mechanisms of a β-defensin in turbot (Scophthalmus maximus)

β-defensins (BDs) are small-molecule cysteine-rich cationic antimicrobial peptides that play an important role in innate immunity against microbial invasion. In this study, a β-defensin (SmBD) was identified and characterized from turbot (Scophthalmus maximus). SmBD has an open reading frame containing 192 bp and encodes a protein of 63 amino acids. It has a predicted signal peptide consisting of 20 amino acids and a mature peptide with six conserved cysteine residues forming three disulfide bonds (C1- C5, C2-C4 and C3-C6). The 3D structure prediction shows an N-terminal α-helix and three reverse parallel β-folds. SmBD showed high sequence identity (70.45% - 95.24%) with β-defensin 2 group members from other teleost species. SmBD had the highest expression in skin of healthy turbot and was significantly up-regulated in mucosal tissues (skin, gill, intestine) after bacteria challenge. SmBD showed antibacterial activity against Vibrio anguillarum, Edwardsiella tarda, Escherichia coli and Streptococcus iniae, and inhibitory effect on the formation of bacterial biofilms. SmBD changed bacterial membrane permeability and affected bacterial morphology, as shown in fluorescence microscopy and scanning electron microscopy analyses, respectively, which indicated that SmBD might exercise antibacterial behaviors via “membrane-attack” mechanism.

Formulation and Characterization of Anti-Bacterial Activity of Silver Nanoparticles Using Root and Leaf of Wedelia trilobata

In the present study one such species, Wedelia trilobata, has be chosen to review the In vitro antibacterial activity of the root extract by using solvent ethanol for the selected plant Wedelia triolobata. The deduction of nanoparticles used to be unalterable by UV-Visible spectroscopy, FTIR, particle size, and zeta potential. The anti-bacterial activity of Wedelia trilobata mediated synthesis silver nanoparticles was tested by disc diffusion assay against standard organisms like Escherichia coli and staphylococcus aureus bacteria. The formation of silver nanoparticles by Wedelia trilobata was initially demonstrated by color changes confirmed by UV-Visible root exhibited a specific absorbance peak around 450 nm and leaf exhibited a specific absorbance peak around 418nm respectively. The Zeta potential of silver nanoparticles was found to be root 0.1 and leaf 0.4, so it indicates the dispersion and stability. The antibacterial activity against Gram-positive Staphylococcus aureus was increased, which was indicated by an increase in the inhibition zone diameter from 3Mm for normal (9.5Mm), standard (12.3Mm), control (11.3Mm), extraction for AgNPs Wedelia trilobata (13.8). 5Mm for normal (7.3Mm), standard (19.4Mm), control (10.5Mm), extraction for AgNPs Wedelia trilobata (19.8). The antibacterial activity against Gram-negative E.coli was increased, which was indicated by an increase in the inhibition zone diameter from 3Mm for normal (7.8Mm), standard (8.5Mm), control (10.2Mm), extraction for AgNPs Wedelia trilobata (14.3). 5Mm for normal (13Mm), standard (19.6Mm), control (15.3Mm) extraction for AgNPs Wedelia trilobata (19.8). The present investigation revealed that the ethanolic Root and aqueous leaf extracts the chosen plant have potential to suppress the expansion of infective bacterial strains.

Characterization of antibacterial activity and mechanisms of two linear derivatives of bactenecin

Antibiotic resistance is a significant global healthcare issue, and the development of alternative classes of antimicrobial agents with new modes of action is therefore critical. In the current study, two derivatives of the antimicrobial peptide bactenecin which were Bac2a, a 12-residue peptide, and Bac8c, an 8-residue peptide were synthesized, then their antimicrobial properties, stabilities, and mechanisms of action were investigated. Results showed that the minimum inhibitory concentrations (MICs) of Bac2a against gram-negative and gram-positive bacteria ranged from 2 to 32 μM, while Bac8c exhibited greater antimicrobial activity with MICs ranging from 2 to 16 μM Bac8c also exhibited lower hemolytic and cytotoxic activities compared with those of Bac2a. The antibacterial activities of the peptides were not inhibited by heat, and Bac8c possessed a higher antibacterial activity in the presence of salts and enzymes. Fluorescence spectroscopy, flow cytometry, and scanning and transmission electron microscopy indicated that Bac8c exhibited high antimicrobial potency by inducing cytoplasmic membrane potential loss, as well as membrane permeabilization and disruption. Based on the results of the analyses, Bac8c represents a promising candidate for novel antimicrobial applications.

Synthesis of ecofriendly copper oxide nanoparticles for fabrication over textile fabrics: Characterization of antibacterial activity and dye degradation potential

Growing concerns over the toxicity of metallic nanoparticles synthesized using physical and chemical techniques seems to be a major hurdle for researchers. Green synthesis of nanoparticles is one of the promising, ecofriendly and safer methods. Utilizing plant sources as reducing agents will replace the use of toxic chemicals for nanoparticle synthesis. Among the various nanoparticles, copper has been theoretically and practically proved for its antimicrobial properties. However, to reduce the risk of copper toxicity, Ruellia tuberosa (R. tuberosa) aqueous extract is used for the synthesis of CuONPs in the present study. Nonetheless, till date no work has been reported on the use of R. tuberosa aqueous extract for the synthesis of CuONPs. In the present study, aqueous extract of R. tuberosa has been used for the synthesis of CuONPs. The synthesis of CuONPs was confirmed by the absorption peak at 327 nm representing the nanorods with an average size of 83.23 nm. Further, the CuONPs revealed antimicrobial effects against clinical pathogens such as Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. Embedding CuONPs on cotton fabrics showed bactericidal activity against the bacterial pathogens. In addition, the photocatalytic property of the CuONPs was divulged by their crystal violet (CV) dye degradation potential. Thus, the green synthesized CuONPs using R. tuberosa could provide a remedy against bacterial pathogens in hospital and industrial environments.

Active Molecular Chitosan (AMC-S1): Preparation and characterization of Antibacterial Activity

The aim of the present study is to prepare the chitosan hydrolysates and characterize their potential antibacterial activity. High molecular weight chitosan (CTSN-H) and medium molecular weight chitosan (MMWC, 2~10-kDa) were further degraded efficiently by using chitosanase from Bacillus subtilis JH-1122. Molecular weight (MW) of the final product was determined by MALDI-TOF MS, showed several peaks ranging from 0.8 to 2.5-kDa. Based on antibacterial activity of the hydrolysates, final products were named as active molecular chitosan (AMC-S1). AMC-S1 was evaluated as IC50 to 12.5 μg/mL of the concentration toward Candida albicans. Our present study demonstrates that AMC-S1 derived from the digestion of CTSN-H and MMWC can be selected as a potent factor affecting on antimicrobial activity against C. albicans for the industry and pharmaceutical applications.

Characterization of antibacterial activity from protein hydrolysates of the macroalga Saccharina longicruris and identification of peptides implied in bioactivity

The macroalga Saccharina longicruris proteins were extracted and hydrolysed with the enzyme trypsin in order to recover antibacterial peptides, which could be used in reducing food spoilage. The >10 kDa protein hydrolysate fraction exhibited activity against the bacterium Staphylococcus aureus with a significant decrease of the maximum specific growth rate, µmax, from concentrations of 0.31 mg/mL to 2.5 mg/mL. Protein precursors were identified in a subfraction (Fr1) enriched in antibacterial peptides using liquid chromatography–tandem mass spectrometry (LC–MS/MS) with database searches. Identified peptides came from different precursors such as a protein similar to ubiquitin, histones, a hypothetical leucine rich repeat protein and a ribosomal protein. These proteins might be associated with the innate immune defences in S. longicruris. Peptidic sequences were chemically synthesized and their bioactivity confirmed, suggesting that activity probably results from synergies between peptides. This is the first time that antibacterial peptides originating from algal protein hydrolysates were isolated and characterized.

Composite copolymer hybrid silver nanoparticles: preparation and characterization of antibacterial activity and cytotoxicity

The AgNPs could adhere to the bacterial membrane through electrostatic force, then damage the bacterial membrane irreversibly and lead to bacterial apoptosis finally.

Antimicrobial Constituents of the Leaves of Mikania micrantha H. B. K

BackgroundTo isolate plant-derived compounds with antimicrobial activity from the leaves of Mikania micrantha, to determine the compounds configuration, and to evaluate their antimicrobial activity against eight plant pathogenic fungi (Exserohilum turcicum, Colletotrichum lagenarium, Pseudoperonispora cubensis, Botrytis cirerea, Rhizoctonia solani, Phytophthora parasitica, Fusarium solani, and Pythium aphanidermatum,) and four plant pathogenic bacteria (gram negative bacteria: Ralstonia dolaanacearum, Xanthomonas oryzae pv. Oryzae, Xanthomonas Campestris pv. Vesicatoria, and Xanthomonas campestris pv. Citri), and four bacteria (gram positive bacteria: Staphyloccocus aureus, Bacillus subtilis, Micrococcus luteus, and Bacillus cereus).Methods and ResultsAntimicrobial constituents of the leaves of M. micrantha were isolated using bioactivity- guided fractionation. The antifungal activity of the isolated compounds was evaluated by the inhibit hypha growth method and inhibit spore germination method. Characterization of antibacterial activity was carried out using the minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs). MIC and MBC were determined by the broth microdilution method. Six compounds – deoxymikanolide, scandenolide, dihydroscandenolide, mikanolide, dihydromikanolide, and m - methoxy benzoic acid – have been isolated from leaves of Mikania micrantha H. B. K. Deoxymikanolide, scandenolide, and dihydroscandenolide were new compounds. The result of bioassay showed that all of isolated compounds were effective against tested strains and deoxymikanolide showed the strongest activity.Conclusions and SignificanceThe leaves of M. micrantha may be a promising source in the search for new antimicrobial drugs due to its efficacy and the broadest range. Meanwhile, adverse impact of M. micrantha will be eliminated.

Characterization of Antibacterial Activity and Potential as Probiotic of Lactic Acid Bacteria Isolated from Goat’s Milk in Algeria

Characterization of Antibacterial Activity and Potential as Probiotic of Lactic Acid Bacteria Isolated from Goat’s Milk in Algeria

Characterization of Antibacterial Activity and Synergistic Effect of Cationic Antibacterial Peptide-resin Conjugates

We synthesized peptide-resin conjugates (1 and 2) by immobilizing <TEX>${\beta}$</TEX>-sheet antibacterial peptide and <TEX>${\alpha}$</TEX> helical antibacterial peptide on PEG-PS resin, respectively. Conjugate 1 showed considerable antibacterial activity in various conditions, whereas conjugate 2 did not exhibit antibacterial activity. The growths of various bacteria were inhibited by conjugate 1 even at lower concentrations than MIC. Conjugate 1 killed bacteria at MIC and had a potent synergistic effect with current antibacterial agents such as vancomycin and tetracycline, respectively. Overall results indicate that polymer surface modification using antibacterial <TEX>${\beta}$</TEX> sheet peptide is a powerful way to prevent microbial contamination on polymer surfaces.