scholarly journals Antibacterial and Biofilm Modulating Potential of Ferulic Acid-Grafted Chitosan against Human Pathogenic Bacteria

2018 ◽  
Vol 19 (8) ◽  
pp. 2157 ◽  
Author(s):  
Chakradhar Dasagrandhi ◽  
Seulki Park ◽  
Won-Kyo Jung ◽  
Young-Mog Kim
Keyword(s):  
Ferulic Acid ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Membrane Integrity ◽  
Microscopic Analysis ◽  
Multi Drug Resistance ◽  
Bactericidal Action ◽  
Electron Microscopic ◽  
Iodide Uptake ◽  
Human Pathogenic Bacteria

The emergence of more virulent forms of human pathogenic bacteria with multi-drug resistance is a serious global issue and requires alternative control strategies. The current study focused on investigating the antibacterial and antibiofilm potential of ferulic acid-grafted chitosan (CFA) against Listeria monocytogenes (LM), Pseudomonas aeruginosa (PA), and Staphylococcus aureus (SA). The result showed that CFA at 64 µg/mL concentration exhibits bactericidal action against LM and SA (>4 log reduction) and bacteriostatic action against PA (<2 log colony forming units/mL reduction) within 24 h of incubation. Further studies based on propidium iodide uptake assay, measurement of material released from the cell, and electron microscopic analysis revealed that the bactericidal action of CFA was due to altered membrane integrity and permeability. CFA dose dependently inhibited biofilm formation (52–89% range), metabolic activity (30.8–75.1% range) and eradicated mature biofilms, and reduced viability (71–82% range) of the test bacteria. Also, the swarming motility of LM was differentially affected at sub-minimum inhibitory concentration (MIC) concentrations of CFA. In the present study, the ability of CFA to kill and alter the virulence production in human pathogenic bacteria will offer insights into a new scope for the application of these biomaterials in healthcare to effectively treat bacterial infections.

scholarly journals Antibacterial and Biofilm Modulating Potential of Ferulic Acid Grafted Chitosan against Human Pathogenic Bacteria

2018 ◽  
Author(s):  
Chakradhar Dasagrandhi ◽  
Seulki Park ◽  
Won-Kyo Jung ◽  
Young-Mog Kim
Keyword(s):  
Ferulic Acid ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Membrane Integrity ◽  
Microscopic Analysis ◽  
Multi Drug Resistance ◽  
Bactericidal Action ◽  
Electron Microscopic ◽  
Iodide Uptake ◽  
Human Pathogenic Bacteria

Emergence of more virulent forms of human pathogenic bacteria with multi drug resistance is a serious global issue and requires alternative control strategies. The current study was focused to investigate the antibacterial and antibiofilm potential of ferulic acid grafted chitosan (CFA) against Listeria monocytogenes (LM), Pseudomonas aeruginosa (PA), and Staphylococcus aureus (SA). The present result showed that CFA at 64 µg/mL concentration exhibit bactericidal action against LM and SA (&gt;4 log reduction) and bacteriostatic action against PA (&lt;2 log CFU) within 24 h of incubation. Further studies based on propidium iodide uptake assay, measurement of material released from the cell, and electron microscopic analysis revealed that the bactericidal action of CFA was due to the altered membrane integrity and permeability. CFA dose-dependently inhibited biofilm formation (52-89% range), its metabolic activity (30.8-75.1% range) and eradicated mature biofilms, and reduced viability (71-82% range) of the test bacteria. Also, the swarming motility of LM was differentially affected at sub-MIC concentration of CFA. In the present study, the ability of CFA to kill and alter the virulence production in human pathogenic bacteria will insight a new scope for the application of these biomaterials in healthcare to effectively treat bacterial infections.

Protein-stabilized silver nanoparticles encapsulating gentamycin for the therapy of bacterial biofilm infections

Nanomedicine ◽  
2021 ◽  
Author(s):  
Sudip Nag ◽  
Arpita Biswas ◽  
Dhrubajyoti Chattopadhyay ◽  
Maitree Bhattacharyya
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Infections ◽  
Microscopic Analysis ◽  
Bacterial Biofilm ◽  
Resistant Bacteria ◽  
Hydrodynamic Diameter ◽  
Drug Resistant ◽  
Electron Microscopic ◽  
Antibacterial Efficiency ◽  
Control Drug

Aim: An antibiotic-conjugated protein-stabilized nanoparticle hybrid system was developed to combat the challenges faced during the treatment of drug-resistant bacterial biofilm-associated infections. Materials & methods: Biocompatible silver nanoparticles were synthesized using intracellular protein and gentamycin was attached. The resulting nanohybrid was characterized and its antibacterial efficiency was assessed against Gram-positive, Gram-negative and drug-resistant bacteria. Results: Spectroscopic and electron microscopic analysis revealed that the nanoparticles were spherical with a diameter of 2–6 nm. Red-shifting of the surface plasmon peak and an increase in hydrodynamic diameter confirmed attachment of gentamycin. The nanohybrid exhibited antibacterial efficiency against a range of bacteria with the ability to inhibit and disrupt bacterial biofilm. Conclusion: A unique nanohybrid was designed that has potential to be used to control drug-resistant bacterial infections in the future.

scholarly journals Antibacterial mode of action of Ginkgo biloba leaf essential oil: Effect on morphology and membrane permeability

2015 ◽  
Vol 10 (2) ◽  
pp. 337 ◽  
Author(s):  
Vivek K. Bajpai ◽  
Ajay Sharma ◽  
Kwang-Hyun Baek
Keyword(s):  
Essential Oil ◽  
Ginkgo Biloba ◽  
Mode Of Action ◽  
Pathogenic Bacteria ◽  
Membrane Integrity ◽  
Spectrometric Analysis ◽  
Electron Microscopic ◽  
Morphological Alterations ◽  
Leaf Essential Oil ◽  
Foodborne Pathogenic Bacteria

<p>This study was aimed to evaluate antimicrobial mode of action of <em>Ginkgo biloba</em> leaf essential oil against foodborne pathogenic bacteria. Gas-chromatography and mass-spectrometric analysis determined 34 different compounds, representing 95.45% of the total oil. The <em>G. biloba</em> leaf essential oil (1,000 µg/disc) showed potential antibacterial effect as diameters of inhibition zones (12.0 ± 0.4-18.0 ± 1.2 mm) along with minimum inhibitory and minimum bactericidal concentration values ranging of 250-1,000 µg/mL. Also the <em>G. biloba</em> leaf essential oil had potential inhibitory effect on the cell viability of the tested pathogens. The scanning electron microscopic analysis using <em>G. biloba</em> leaf essential oil showed considerable morphological alterations on the cell wall of tested pathogens. The oil revealed its mode of action on membrane integrity as confirmed by release of extracellular ATP, increase of 260-nm absorbing materials and increased leakage of potassium ions against foodborne pathogenic bacteria.  </p><p> </p>

scholarly journals Mechanism of BceAB-type transporter: Resistance by lipid II flipping

2020 ◽  
Author(s):  
Julia Zaschke-Kriesche ◽  
Sandra Unsleber ◽  
Irina Voitsekhovskaia ◽  
Andreas Kulik ◽  
Lara V. Behrmann ◽  
...  
Keyword(s):  
Cell Wall ◽  
Antimicrobial Peptides ◽  
Streptococcus Agalactiae ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Human Pathogenic Bacteria ◽  
Lipid Ii ◽  
Multiresistant Bacteria

AbstractTreatment of bacterial infections are the great challenge of our era due to the evolved resistance mechanisms against antibiotics. The Achilles heel of bacteria is the cell wall especially during the needs of its synthesis and cell division. Here lipid II is an essential cell wall precursor component synthesized in the cytosol and flipped into the outer leaflet of the membrane prior to its incorporation into the cell wall.Compounds targeting the cell wall or its biosynthesis precursors have been around for decades and have been used as antibiotics against bacterial infections like meningitis, pneumonia and endocarditis. Antimicrobial peptides (AMPs) have proven to be a promising weapon against multiresistant bacteria. However, the Bacitracin efflux (BceAB)-type ATP binding cassette transporters expressed in the membrane of human pathogenic bacteria have been shown to confer resistance to these alternative antibiotics, thereby hampering their medical development.In Streptococcus agalactiae COH1 the BceAB-type transporter NsrFP (SaNsrFP) confers high-level resistance against the antimicrobial peptide nisin, a member of the lantibiotic subfamily. We showed that SaNsrFP provides a novel resistance mechanism by flipping lipid II back into the cytosol, thereby preventing the binding of nisin as well as other lipid II targeting compounds. This is intriguing since a relatively simple reaction mediates resistance to human pathogenic bacteria to lipid II targeting antibiotics, regardless of their structure.Significance StatementThe ABC-transporter NsrFP from Streptococcus agalactiae (SaNsrFP) belongs to the BceAB-type transporters. Several BceAB-type transporters are known to confer resistance against multiple antimicrobial peptides. In this study a new resistance mechanism was identified, which is based on the reduction of the number of cell wall precursor lipid II molecules on the cell surface mediated by SaNsrFP. SaNsrFP flips lipid II, which are considered to be the target for many antibiotics, back into the cytoplasm. With this newly gained knowledge about the resistance mechanism of BceAB-type transporters, novel strategies can be established to overcome or bypass this resistance in human pathogenic bacteria.

scholarly journals Effect of Plasmonic Gold Nanoprisms on Biofilm Formation and Heat Shock Proteins Expression in Human Pathogenic Bacteria

2021 ◽  
Vol 14 (12) ◽  
pp. 1335
Author(s):  
Rihab Lagha ◽  
Fethi Ben Abdallah ◽  
Amine Mezni ◽  
Othman M. Alzahrani
Keyword(s):  
Gold Nanoparticles ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Western Blot ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Biofilm Inhibition ◽  
Human Pathogenic Bacteria ◽  
Gold Nanoprisms ◽  
Shock Proteins

Gold nanoparticles have gained interest in biomedical sciences in the areas of nano-diagnostics, bio-labeling, drug delivery, and bacterial infection. In this study, we examined, for the first time, the antibacterial and antibiofilm properties of plasmonic gold nanoprisms against human pathogenic bacteria using MIC and crystal violet. In addition, the expression level of GroEL/GroES heat shock proteins was also investigated by western blot. Gold nanoparticles were characterized by TEM and EDX, which showed equilateral triangular prisms with an average edge length of 150 nm. Antibacterial activity testing showed a great effect of AuNPs against pathogenic bacteria with MICs values ranging from 50 μg/mL to 100 μg/mL. Nanoparticles demonstrated strong biofilm inhibition action with a percentage of inhibition ranging from 40.44 to 82.43%. Western blot analysis revealed that GroEL was an AuNPs-inducible protein with an increase of up to 66.04%, but GroES was down-regulated with a reduction of up to 46.81%. Accordingly, plasmonic gold nanoprisms, could be a good candidate for antibiotics substitution in order to treat bacterial infections.

Evaluation and Microanalysis of Parasitic and Bacterial Agents of Egyptian Fresh Sushi, Salmo salar

2019 ◽  
Vol 25 (6) ◽  
pp. 1498-1508 ◽  
Author(s):  
Sara S. Abdel-Hakeem ◽  
Ghada Abd-Elmonsef Mahmoud ◽  
Hanan H. Abdel-Hafeez
Keyword(s):  
Salmo Salar ◽  
Pathogenic Bacteria ◽  
Developmental Stages ◽  
Periodic Acid ◽  
Muscular Tissue ◽  
Electron Microscopic ◽  
Serratia Plymuthica ◽  
Periodic Acid Schiff ◽  
Thin Sections ◽  
Human Pathogenic Bacteria

AbstractThe present study aimed to evaluate the quality of fresh sushi in Egypt. Fifty samples of sushi (Salmo salar) were collected from restaurants in Alexandria, Egypt. Paraffin, semi-thin and ultra-thin sections were used for parasitological analysis by light and transmission electron microscopy. Bacteria were isolated by the dilution plate and direct plate methods and identified by a Vitek system. Twenty (40%) of the total examined samples showed microsporidia and helminth metacercariae infections. Histochemical stains showed distinct pinkish-red pyriform microspores embedded in muscular tissue stained with Gram, periodic acid-Schiff (PAS), and Ziehl–Neelsen (ZN) stains. Semi-thin sections showed double membrane xenoma-inducing granulomas containing spores at different developmental stages. Empty sporophorous vesicles and free spores were observed in the electron microscopic images. A bacteriological assay showed forty samples (80%) contaminated with human pathogenic bacteria with the average total bacterial counts ranging from 32 to 526 CFU/g. Four species of human pathogenic bacteria were identified in the examined samples, namely Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, and Serratia plymuthica in 40, 38, 11, and 6 samples, respectively. These constitute the first record of fresh sushi product in Egypt and indicate the potential pathogenicity associated with raw seafood products.

scholarly journals Discovery of bactericides as an acute mitochondrial membrane damage inducer

2021 ◽  
pp. mbc.E21-04-0191
Author(s):  
Ryan Houston ◽  
Yusuke Sekine ◽  
Mads B Larsen ◽  
Kei Murakami ◽  
Steven J Mullett ◽  
...  
Keyword(s):  
Stress Responses ◽  
Mitochondrial Membrane ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Microscopic Analysis ◽  
Mitochondrial Membranes ◽  
Inner Mitochondrial Membrane ◽  
Electron Microscopic ◽  
Bacterial Membranes ◽  
Anionic Phospholipids

Mitochondria evolved from endosymbiotic bacteria to become essential organelles of eukaryotic cells. The unique lipid composition and structure of mitochondrial membranes are critical for the proper functioning of mitochondria. However, stress responses that help maintain the mitochondrial membrane integrity are not well understood. One reason for this lack of insight is the absence of efficient tools to specifically damage mitochondrial membranes. Here, through a compound screen, we found that two bis-biguanide compounds, Chlorhexidine and Alexidine, modified the activity of the inner mitochondrial membrane (IMM)-resident protease OMA1 by altering the integrity of the IMM. These compounds are well-known bactericides whose mechanism of action has centered on their damage-inducing activity on bacterial membranes. We found Alexidine binds to the IMM likely through the electrostatic interaction driven by the membrane potential as well as an affinity for anionic phospholipids. Electron microscopic analysis revealed that Alexidine severely perturbated the cristae structure. Notably, Alexidine evoked a specific transcriptional/proteostasis signature that was not induced by other typical mitochondrial stressors, highlighting the unique property of Alexidine as a novel mitochondrial membrane stressor. Our findings provide a chemical-biological tool that should enable the delineation of mitochondrial stress-signaling pathways required to maintain the mitochondrial membrane homeostasis.

scholarly journals Semi- and fully synthetic carbohydrate vaccines against pathogenic bacteria: recent developments

2021 ◽  
Author(s):  
Magdalena E. Zasłona ◽  
A. Michael Downey ◽  
Peter H. Seeberger ◽  
Oren Moscovitz
Keyword(s):  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
High Efficiency ◽  
Low Cost ◽  
Cost Effective ◽  
Human Pathogenic Bacteria ◽  
Effective Manner ◽  
Recent Developments ◽  
Synthetic Carbohydrate ◽  
Carbohydrate Vaccines

The importance of vaccine-induced protection was repeatedly demonstrated over the last three decades and emphasized during the recent COVID-19 pandemic as the safest and most effective way of preventing infectious diseases. Vaccines have controlled, and in some cases, eradicated global viral and bacterial infections with high efficiency and at a relatively low cost. Carbohydrates form the capsular sugar coat that surrounds the outer surface of human pathogenic bacteria. Specific surface-exposed bacterial carbohydrates serve as potent vaccine targets that broadened our toolbox against bacterial infections. Since first approved for commercial use, antibacterial carbohydrate-based vaccines mostly rely on inherently complex and heterogenous naturally derived polysaccharides, challenging to obtain in a pure, safe, and cost-effective manner. The introduction of synthetic fragments identical with bacterial capsular polysaccharides provided well-defined and homogenous structures that resolved many challenges of purified polysaccharides. The success of semisynthetic glycoconjugate vaccines against bacterial infections, now in different phases of clinical trials, opened up new possibilities and encouraged further development towards fully synthetic antibacterial vaccine solutions. In this mini-review, we describe the recent achievements in semi- and fully synthetic carbohydrate vaccines against a range of human pathogenic bacteria, focusing on preclinical and clinical studies.

scholarly journals Antagonistic Activity of Endophytic Fungi Isolated from Globba patens Miq. Rhizome against Human Pathogenic Bacteria

2021 ◽  
Vol 15 (1) ◽  
pp. 232-239
Author(s):  
Anisa Lutfia ◽  
Erman Munir ◽  
Yurnaliza Yurnaliza ◽  
Mohammad Basyuni
Keyword(s):  
Endophytic Fungi ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Morphological Characteristics ◽  
Antibacterial Activities ◽  
Antagonistic Activity ◽  
Dual Culture ◽  
E Coli ◽  
Human Pathogenic Bacteria ◽  
Wide Range

The emergence of bacterial infections caused by resistant strains poses a threat to the development of new antibiotics. The majority of antibiotics being produced has been accelerated through the finding of newly reported natural products, especially those originated and produced by biological sources. Endophytic fungi residing in medicinal plants may be regarded as potential sources and encourage the exploration of more plant species for their antimicrobial activity. Our current study reports on the assemblage of endophytic fungi that colonize the rhizomes, using Globba patens a representative of Zingiberaceous species from North Sumatra. Twenty-six fungal morphotypes were obtained and differentiated by their morphological features. Each isolate was tested against human pathogenic bacteria namely Staphylococcus aureus ATCC® 29213™, Methicillin-resistant S. aureus (MRSA) ATCC® 43300™, Escherichia coli ATCC® 25922™, and Enteropathogenic E. coli (EPEC) K11 in a dual culture assay. The results revealed that the majority of fungal isolates were strong antagonists against S. aureus and E. coli but not against MRSA and EPEC. Isolate Gp07 was the most potential fungus with a wide range of antibacterial activities and was subjected to further species-level identification based on its morphological characteristics and DNA sequence in the ITS-rDNA region. The isolate Gp07 was identified as Colletotrichum siamense, yet the presence of C. siamense in the rhizome of G. patens is not fully understood while possibly being characterized as the antibiotics-producing agent in the future.

Curcumin inhibits FtsZ assembly: an attractive mechanism for its antibacterial activity

2008 ◽  
Vol 410 (1) ◽  
pp. 147-155 ◽  
Author(s):  
Dipti Rai ◽  
Jay Kumar Singh ◽  
Nilanjan Roy ◽  
Dulal Panda
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Microscopic Analysis ◽  
Antibacterial Drug ◽  
Gtpase Activity ◽  
Electron Microscopic ◽  
Z Ring ◽  
Ftsz Assembly ◽  
Antibacterial Drug Target

The assembly and stability of FtsZ protofilaments have been shown to play critical roles in bacterial cytokinesis. Recent evidence suggests that FtsZ may be considered as an important antibacterial drug target. Curcumin, a dietary polyphenolic compound, has been shown to have a potent antibacterial activity against a number of pathogenic bacteria including Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus. We found that curcumin induced filamentation in the Bacillus subtilis 168, suggesting that it inhibits bacterial cytokinesis. Further, curcumin strongly inhibited the formation of the cytokinetic Z-ring in B. subtilis 168 without detectably affecting the segregation and organization of the nucleoids. Since the assembly dynamics of FtsZ protofilaments plays a major role in the formation and functioning of the Z-ring, we analysed the effects of curcumin on the assembly of FtsZ protofilaments. Curcumin inhibited the assembly of FtsZ protofilaments and also increased the GTPase activity of FtsZ. Electron microscopic analysis showed that curcumin reduced the bundling of FtsZ protofilaments in vitro. Further, curcumin was found to bind to FtsZ in vitro with a dissociation constant of 7.3±1.8 μM and the agent also perturbed the secondary structure of FtsZ. The results indicate that the perturbation of the GTPase activity of FtsZ assembly is lethal to bacteria and suggest that curcumin inhibits bacterial cell proliferation by inhibiting the assembly dynamics of FtsZ in the Z-ring.

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