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Order Blubervirales: Core Protein
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
It is an unexpected and intriguing finding that the HBc peptide 147–183 representing the arginine rich domain (ARD) of the HBc molecule possesses broad spectrum anti-Gram positive and anti-Gram negative microbial activity (including some multidrug resistant microorganisms) at micromolar concentrations (Chen HL et al. 2013, 2016). The antimicrobial activity is specific and becomes apparent by membrane permeabilisation or DNA binding. The sequences HBc153–176 or HBc147–167 were necessary and sufficient for antimicrobial activity against Pseudomonas aeruginosa and Klebsiella peumoniae. The introduction of such promising antimicrobial peptides would be currently important, as overall microbial resistance to antibiotics is rapidly growing.
Selective Antimicrobial Agents from Terrestrial Plants A Hope in the Battle of Infection
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Fadia S. Youssef, Mohamed L. Ashour
In addition, C. infortunatum leaves extracted with different solvents like methanol, distilled water, acetone, n-hexane and dichloromethane are examined for their antimicrobial potential against Staphylococcus pasteuri as Gram-positive bacteria and Pseudomonas aeruginosa as a Gram-negative one. It showed a maximum inhibition zone at 5% against both tested organisms. Besides, methanol extract showed high content of phenols. Quantification of flavonoids and tannins revealed that C. infortunatum leaves possess high flavonoid content, which is 12.17 mg/g and total tannins equal to 13.87 mg/g in acetone extract. Purification of anthocyanin from an in vitro culture of C. infortunatum was done using various chromatographic techniques, which was further checked for purity using HPLC and the molar absorptivity assay. The antimicrobial activity was assessed by determining the Minimum Inhibitory Concentration (MIC) and Minimum Killing Concentration (MKC). The purified anthocyanins showed significant antimicrobial activity with different degrees with C. albicans, S. aureus, P. aeruginosa displayed significant values followed by MRSA, E. coli and A. flavus, approaching that of standard antibiotics. In contrast, E. faecalis showed a higher resistance. The mechanistic behavior shown was proved by analysis of intracellular potassium leakage and bacterial membrane integrity (Sivamaruthi et al. 2018).
Antimicrobial Properties of Traditional Medicinal Plants: Status and Potential
Published in Megh R. Goyal, Durgesh Nandini Chauhan, Plant- and Marine-Based Phytochemicals for Human Health, 2018
V. Duraipandiyan, T. William Raja, Naif Abdullah Al-Dhabi, Ignacimuthu Savarimuthu
Antimicrobial compounds possess properties that are effective against microbial growth and several methods are used to assess the antimicrobial activity. Various tribes have depended upon plant-based drugs for their basic medical needs and diseases have been cured using different parts of medicinal plants. Administration of TMs does not cause side effects. Consequently, TMs are playing a pivotal role in protecting human beings from microorganisms.
Is there a niche for zinc oxide nanoparticles in future drug discovery?
Published in Expert Opinion on Drug Discovery, 2023
ZnO nanoparticles associated with several biological effects could be the basis of therapeutic outcome. Among those reported in literature, antimicrobial activity is one of the most studied. The mechanism for the antimicrobial activity is based on reactive oxygen species (ROS) generation at the particle surface, release of zinc ion, and membrane dysfunction. Both antimicrobial and antibacterial activities are based on the generation of ROS on the surface of ZnO. Gram negative and positive spores resistant to high temperatures and high pressure can be killed with ZnO nanoparticles depending on both concentration and extent (exposure time). This activity is believed to result from generation of hydrogen peroxide and binding of particles to the surface of the bacteria with static forces. Particle size variation and surface area/volume ratio affect the antibacterial activity [1].
Molecular insights into probiotic mechanisms of action employed against intestinal pathogenic bacteria
Published in Gut Microbes, 2020
Winschau F. van Zyl, Shelly M. Deane, Leon M.T. Dicks
Bacteriocin-like inhibitory substances (BLIS) have a broader spectrum of antimicrobial activity. Many of these compounds are not fully characterized or do not share characteristics typical of bacteriocins.12 The antimicrobial activities are not related to the production of lactic acid, other organic acids, or hydrogen peroxide.12,154Lactobacillus rhamnosus GG secretes an antimicrobial substance with inhibitory activity against Clostridium spp., Staphylococcus spp., Enterobacteriaceae, Streptococcus spp., Bacteriodes spp., and Pseudomonas spp.155 This low molecular weight (LMW) substance is characterized as heat-stable, distinct from lactic and acetic acids, and closely resembles a microcin that is normally produced by Enterobacteriaeae spp. These characteristics suggest that it could be a BLIS.12 Similar substances with molecular weights and broad activity spectrums uncharacteristic of bacteriocins are produced by other lactobacilli, including strains of L. acidophilus and L. delbrueckii, their bactericidal affects are related to neither lactic acid nor hydrogen peroxide.156,157 Other studies have identified bacteriocin-like antimicrobial substances produced by several Bifidobacterium strains with broad spectrums of activity against both Gram-positive and Gram-negative pathogens such as L. monocytogenes, Salmonella spp. and E. coli spp.158–160
Antimicrobial lipids in nano-carriers for antibacterial delivery
Published in Journal of Drug Targeting, 2020
Qianyu Zhang, Wen Wu, Jinqiang Zhang, Xuefeng Xia
The underlying mechanisms for their antimicrobial activity was also investigated. Due to the amphipathic nature of lipids, the main target for antimicrobial lipid is the cell membrane along with other crucial process in cell function [17,25]. Cell membrane lysis is the most direct bactericidal actions of fatty acids and monoglycerides, which in part explains why generally Gram-positive species are more prone to be killed by them than Gram-negative ones, as the latter usually possess an outer membrane. Some Gram-negative species are still susceptible, such as Neisseria, Haemophilus, Moraxella, Chlamydia, Helicobacter and Campylobacter, and for Neisseria and Haemophilus this might be due to their different lipopolysaccharide (LPS) structure compared with other Gram-negative species, and this required further elucidation [3,25–30]. Free fatty acid could also inhibit cell membrane-associated enzymes activity which halts bacterial growth [25]. They could interfere with energy production by uncoupling oxidative phosphorylation, impairing nutrient uptake and disrupting electron transport chain (Figure 2) [17]. Another possible mechanism might be the inhibition of the biosynthesis of fatty acid of the targeted bacteria, which has long been one of the goals for pharmaceutical companies since there might be little chance of cross-resistance [31,32].