Antibacterial Action Research Articles

Synthesis, structure, and biological activity of sodium, zinc, and magnesium mono- and bis-1-alkoxy-4-(2′-naphthyl)-1,4-dioxo-2-buten-2-olates

The search for new biologically active compounds is a key area of chemical science. Therefore, the synthesis of compounds with a potentially bactericidal effect seems relevant. In order to extend the range of biologically active substances, the synthesis of sodium 4-(2’-naphthyl)-1,4-dioxo-1-ethoxy-2-buten-2-olate and sodium 1-butoxy-4-(2´-naphthyl)-1,4-dioxo-2-buten-2-olate was carried out by Claisen condensation of equimolar amounts of 2-acetonaphtone and dialkyloxalates in a non-polar medium in the presence of sodium as a condensing agent. Bidentate mononuclear metal chelates were obtained by the metal exchange reaction of sodium oxoenolates with Zn(II) and Mg(II) salts. The structure of the synthesized compounds was confirmed by infrared spectroscopy, (1Н, 13С) nuclear magnetic resonance spectroscopy, and mass spectrometry. The infrared spectra of solid samples of sodium oxoenolates and metal complexes contain bands of stretching vibrations of ester carbonyl groups, skeletal vibrations of aromatic rings, as well as “ether” bands due to vibrations of C–O–C bonds. The 1Н and 13С nuclear magnetic resonance spectra recorded in CDCl3 and Dimethyl sulfoxide-d6 are characterized by a complete set of all expected signals with chemical shift values that are well comparable with the reference data. In the mass spectra of the analyzed compounds, recorded in an acetonitrile solution in the electrospray mode, signals of [M+H]+ and [M+Na]+ protonated and cationized molecules are observed. The bactericidal action of the synthesized preparations was assessed using the agar well diffusion method in combination with the serial dilution method. The biological activity of sodium 4-(2’-naphthyl)-1,4-dioxo-1-ethoxy-2-buten-2-olate against Pseudomonas Aeruginosa and Staphylococcus Aureus, as well as sodium 1-butoxy-4-(2’-naphthyl)-1,4-dioxo-2-buten-2-olate against Pseudomonas Aeruginosa, was revealed. Pronounced resistance of Salmonella spp. to the studied compounds was established.

Antibacterial cationic porous organic polymer coatings via an adsorption-contact-photodynamic inactivation strategy for treatment of drug-resistant bacteria

Although photodynamic therapy (PDT) has great potential for treating severely infected wounds, it is restricted by the short lifetime, limited diffusion distance of reactive oxygen species (ROS), and incomplete contact with bacteria. Herein, we report a novel nanosized ionic porous organic polymer (TPAPy-IPOP) based on the triphenylamine (TPA) moiety. Strong electron-deficient cationic groups were introduced into TPA to construct the donor–acceptor (D–A) system, in which the photoelectric effect of TPAPy-IPOP was greatly enhanced, and it was easily excited to produce ROS under irradiation with visible light. The introduction of cations not only facilitated bacterial adsorption by TPAPy-IPOP via electrostatic attraction, which was more conducive to killing bacteria by ROS, but also inactivated bacteria by the cations directly. The nanosized TPAPy-IPOP remained suspended in water for several months and could be sprayed onto various substrates to form a durable coating with excellent antibacterial properties. The in vivo results proved that the silk fibroin/polyvinyl alcohol non-woven fabric (SF/PVA) coated with TPAPy-IPOP could create and maintain a sterile microenvironment at a wound site. The rapid reduction in inflammation resulting from its bactericidal action accelerated the wound healing rate. Collectively, this design is expected to offer a generalizable approach for developing novel antibacterial therapeutic photosensitizers, especially for infected wound treatment.

Antibacterial and Cell-Viability of Hydroxyapatite Derived from Waste Marine Shell for Biomedical Applications

The present study discusses on the functional groups, structural characterization and thermal behaviour of Crassostrea angulata shell used for the synthesis of a biocompatible hydroxyapatite material. The hydroxyapatite was synthesized from C. angulata shell through precipitation method and characterized using XRD, FTIR, FE-SEM, EDX mapping, HR-TEM and SAED pattern. The formation of hydroxyapatite was confirmed from the high intense X-ray diffraction lines and by the presence of chemical groups such as PO43–, OH– and CO32–. The structural changes during the formation of hydroxyapatite from the thermal decomposition of C. angulata shell were studied through XRD and TG-DTA. The morphology study by FE-SEM indicates that the synthesized hydroxyapatite materials were in the form of clusters of rod-like particles. The SAED patterns and XRD spectral lines confirmed the crystalline nature of the synthesized hydroxyapatite. The antibacterial activity and cell viability assay of prepared hydroxyapatite were studied to assess its suitability in various biomedical applications. The antibacterial activity of hydroxyapatite was assessed against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus saprophyticus) bacterial strains. The cytocompatibility of hydroxyapatite was assessed through an MTT assay using osteoblast cells (MG-63 cell). Thus, the prepared hydroxyapatite shows good antibacterial action and cell viability nature and it can be applied in various biomedical applications.

On the potential activity of hyaluronic acid as an antimicrobial agent: experimental and computational validations.

This century has seen the rise of antibiotic resistance as a significant public health problem. In addition, oxidative stress may also be a factor in selecting resistant strains of bacteria. The current study analyzed microbially produced hyaluronic acid's antibacterial activity and antioxidant activity. It had significant antibacterial action against strains of Staphylococcus aureus and Escherichia coli, with the IC50 value obtained being 487.65µgmL-1 for antioxidant assay. Our molecular docking investigations of hyaluronic acid on tyrosyl-tRNA synthetase (Staphylococcus aureus: -6.13kcal/mol, Escherichia coli: -5.79kcal/mol) and topoisomerase II DNA gyrase (Staphylococcus aureus: -5.02kcal/mol, Escherichia coli: -4.90kcal/mol) confirmed the ligands' possible binding mode to the appropriate targets' sites. We also employed molecular dynamics simulation and showed that HA binds more strongly with 1JIL (-85.455 ± 12.623kJ/mol) compared to 2YXN (-49.907 ± 64.191kJ/mol), 5CDP (-47.285 ± 13.925kJ/mol), and 6RKS (-45.306 ± 21.338kJ/mol). We also report that the ligand forms several hydrogen bonds in molecular simulation, implying regular interaction with key residues of the enzymes. The results in this study indicate the potential use of HA in the vast field of applications having both asthetic and medicinal values.

A Review of Bacterial Biofilm Components and Formation, Detection Methods, and Their Prevention and Control on Food Contact Surfaces

The microbial biofilms are a community of microorganisms that adhere to each other and to surfaces, typically in a mucilaginous or gel-like matrix composed of extracellular polymeric substances, including polysaccharides, proteins, lipids, and DNA. In the food industry, the bacterial biofilms may be formed on different surfaces and cause post-processing contamination or cross-contamination from the food contact surfaces to food products. Conventional cleaning and sanitizing methods are often ineffective at removing bacterial biofilms. Among more recent alternative methods proposed to address this problem are the use of hydrolytic enzymes, essential oils, and bacteriocins. These methods show promise since their antibacterial and antibiofilm actions involve degradation of the extracellular polymeric matrix of the biofilm and lead to inhibition of the foodborne pathogens present. Understanding the limitations and mechanisms of action of enzymes, bacteriocins, and essential oils in controlling bacterial biofilms on foods and food contact surfaces is essential for developing solutions to prevent and control biofilm formation. This review critically summarizes the current knowledge of bacterial biofilm components, their formation, detection methods, prevention, and removal from food contact surfaces.

Ultrasonic-aided preparation of poly(vanillin-co-thiophene)/green Fe₃O₄ nanocomposites via solution mixing for methyl orange adsorption and antibacterial applications

This work describes the preparation of novel nanocomposite materials comprising a newly synthesized semiconducting copolymer, poly(vanillin-co-thiophene) (PVTH), blended with different weight proportions (3 %, 6 %, and 9 % by weight) of greenly synthesized magnetite nanoparticles (GFe3O4 MNPs) via solution mixing, assisted by ultrasonic irradiation. PVTH copolymer was synthesized through the polycondensation of vanillin, a bioderived aldehyde, and thiophene, catalyzed by sulfuric acid. GFe3O4 MNPs were prepared via the coprecipitation method with mint extract as an environmentally friendly stabilizer. The physicochemical properties of the prepared samples were investigated by 1H NMR, 13C NMR, FTIR, XRD, UV–vis, TGA, FE-SEM/Eds, AFM, VSM, tauc plot method and the four-points probe measurement. The samples were evaluated for two applications: methyl orange (MO) adsorption from aqueous solutions and antibacterial activities against Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and Bacillus) bacterial strains. The results showed that ultrasound irradiation facilitated the easy preparation of well-dispersed and homogeneous nanocomposites with combined semiconducting and magnetic properties and improved thermal stability compared to the parent PVTH. The most effective nanocomposite for MO removal was the sample containing 9 % GFe3O4 MNPs, whose adsorption behavior followed pseudo-second-order kinetics and Freundlich isotherm. Its maximum adsorption capacity was 103.79 mg g−1. In addition, all samples showed antibacterial action against the tested bacterial strains, with PVTH showing the highest efficacy, followed by PVTH/GFe3O4 nanocomposites.

The Potential of Thymus serpyllum Essential Oil as an Antibacterial Agent against Pseudomonas aeruginosa in the Preservation of Sous Vide Red Deer Meat.

Foodborne infections caused by microbes are a serious health risk. Regarding this, customer preferences for "ready-to-eat" or minimally processed (MP) deer meat are one of the main risk factors. Given the health dangers associated with food, essential oil (EO) is a practical substitute used to decrease pathogenic germs and extend the shelf-life of MP meals. Nonetheless, further data regarding EO use in MP meals are required. In order to evaluate new, safer alternatives to chemicals for disease control and food preservation, this research was carried out in the following areas to assess the antibacterial and antibiofilm characteristics of Thymus serpyllum (TSEO) essential oil, which is extracted from dried flowering stalks. Furthermore, this study applied an essential oil of wild thyme and inoculated the sous vide deer meat with Pseudomonas aeruginosa for seven days at 4 °C in an effort to prolong its shelf-life. Against P. aeruginosa, the essential oil exhibited potent antibacterial action. The findings of the minimal biofilm inhibition concentration (MBIC) crystal violet test demonstrated the substantial antibiofilm activity of the TSEO. The TSEO modified the protein profiles of bacteria on glass and plastic surfaces, according to data from MALDI-TOF MS analysis. Moreover, it was discovered that P. aeruginosa was positively affected by the antibacterial properties of TSEO. The anti-Pseudomonas activity of the TSEO was marginally higher in vacuum-packed sous vide red deer meat samples than in control samples. The most frequently isolated species from sous vide deer meat, if we do not consider the applied bacteria Pseudomonas aeruginosa, were P. fragi, P. lundensis, and P. taetrolens. These results highlight the antibacterial and antibiofilm qualities of TSEO, demonstrating its potential for food preservation and extending the shelf-life of deer meat.

Sustainable synthesis of multifaceted copper oxide nanoparticles from Euphorbia tirucalli: Unveiling antimicrobial and catalytic potential

This work presents Euphorbia tirucalli mediated green synthesis of multi-purpose copper oxide nanoparticles (ET@CuO-NPs) exhibiting enhanced antimicrobial activity. These plant extract capped nanoparticles were characterized using sophisticated techniques such as FTIR, Raman, UV–Vis, SEM, HR-TEM, DLS, zeta potential, XPS and XRD. A uniform rod-shaped morphology was observed in HR-TEM images with size around 50 nm. Antibacterial and antifungal activity was investigated by agar well diffusion method. The bactericidal action was confirmed by zone of inhibition of 28 mm and 34 mm respectively against gram-negative and a gram-positive bacterium. The nanoparticles also show excellent antioxidant activity via free radical scavenging by DPPH. The scope of ET@CuO-NPs was extended to catalytic reduction of nitroaromatic compounds into their corresponding amino derivatives. The reduction of 4-nitrophenol, a model nitroaromatic pollutant could be completed within just 6 min with a recycling efficiency of 8 cycles. Thus, the multifaceted ET@CuO-NPs exhibited diverse therapeutic and catalytic potential.

Synergistic Action of Vanillic Acid-Coated Titanium Oxide Nanoparticles: Targeting Biofilm Formation Receptors of Dental Pathogens and Modulating Apoptosis Genes for Enhanced Oral Anticancer Activity.

The prevalence of bacterial and fungal infections is caused byS. aureus, S. mutans, E. faecalis, and Candida albicans are often associated with dental illnesses. In the present study, a unique strategy was used to combat these diseases by fabricatingtitanium dioxide nanoparticles (TiO2 NPs) conjugated with the plant-based molecule vanillic acid (VA).Molecular modeling investigations were performed to better understand the interactions among vanillic acid and dental pathogen receptors using the Autodock program. The findings indicated that VA-TiO2 NPs exhibited strong free radical scavenging activity. Additionally, they showed excellent antibacterial action towards dental pathogens, with a minimum inhibition level of 60 μg/mL. Furthermore, at doses of 15 μg/mL, 30 μg/mL, 60 μg/mL, and 120 μg/mL, VA-TiO2 NPs demonstrated concentration-dependent apoptotic impacts on human oral carcinoma cells. Apoptotic gene over-expression was identified by the molecular perspectives that revealed the anticancer mechanism of VA-TiO2 NPs on KB cells. This study highlights the promising suitability of VA-TiO2 NPs for dental applications due to their robust antioxidant, anticancer, and antimicrobial characteristics. These nanoparticles present an evident prospect for addressing oral pathogen challenges and improving overall oral health.

Assessment of the influence of synthetic peptide of the active center of granulocyte-macrophagal colony-stimulating factor – ZP2 on the growth properties of Corynebacterium spp.

The goal is to study the effect of the synthetic peptide of the active center of the granulocyte-macrophage coline-stimulating factor ZP2 on the growth properties and biofilm formation of microorganisms of the genus Corynebacterium spp. In vitro experiments were carried out on 13 isolates of Corynebacterium spp., including C. amycolatum (n = 7), C. propinquum (n = 2) and C. pseudodiphtheriticum (n = 4)), previously isolated from healthy individuals and are part of the Network Collection of Symbiotic Microorganisms and Their Consortia of the Institute for Cellular and Intracellular Symbiosis UrB RAS (Orenburg, Russia). The effect of different concentrations of the ZP2 peptide on the growth properties (planktonic culture growth and biofilm formation) of test strains was assessed in 96-well polystyrene plates. The inhibitory effect of the ZP2 peptide on the growth of planktonic culture was assessed by the Inhibition Index (%), on biofilm formation – by the Degree of Inhibition of Biofilm Formation (%). It was experimentally established that after 2, 4, 6 and 24 hours, a dose-dependent inhibition of the growth of planktonic cultures of all studied bacterial strains was observed under the influence of various concentrations of ZP2 (0.5-2.0 μg/ml). In this case, the inhibitory effect of the ZP2 peptide depended both on its concentration in the cultivation medium and on the growth phase of the test strain of bacteria. The maximum inhibition of the growth of planktonic culture of all studied bacterial strains under the influence of various concentrations of the ZP2 peptide was observed after 24 hours and ranged from 89.3±1.9 to 94.1±1.8% in C. amycolatum, and in C. propinquum from 90.0±0.6 to 96.7±0.3%, in C. pseudodiphtheriticum from 92.2±2.1 to 95.1±1.3. The ZP2 peptide also had a significant effect on biofilm formation in all test cultures studied. The reduction in biofilm formation depended on the concentration of the peptide and ranged from 62.4 to 78.4% in C. amycolatum, from 70.9 to 79.6% in C. propinquum, and from 76 to 82.7% in C. pseudodiphtheriticum. Thus, the antibacterial effect of the ZP2 peptide was revealed against the studied strains of corynebacteria species C. amycolatum, C. propinquum and C. pseudodiphtheriticum. According to available data, the ZP2 peptide is a drug with a wide spectrum of action that has an inhibitory effect not only on the studied actinobacteria, but also, according to literature data, on staphylococci and enterobacteria. An important prospect of the study is to reveal the mechanism of the antibacterial action of the ZP2 peptide with the characteristics of the effective concentration of the substance against pathogens and representatives of normal flora.

Engineering Coatings Inspired by Cell Membrane Thermal Dynamics to Enhance Photothermal Therapy and Osteogenesis for Implant Infections.

Photothermal therapy (PTT) encounters challenges of rapid thermal loss and potential tissue damage. In response, we propose a Heat-Boost and Lock implant coating strategy inspired by the thermal adaptation of biological membranes, enabling precise local photothermal utilization. This coating incorporates a poly(tannic acid) (pTA) bridging layer on implants, facilitating stable layer-by-layer integration of a black phosphorus (BP) photothermal layer and a top cell membrane Heat-Boost and Lock layer. The cell membrane layer significantly curtails photothermal loss (extending the heat retention by 17.62%) and stores energy within its phospholipid bilayer, boosting photothermal effects near implants (achieving a temperature increasement of 275%). Theoretical analysis indicates that these local heat preservation properties of the cell membrane arise from its low thermal conductivity and phase-change properties. In a Staphylococcus aureus-infected bone implant model, our coating demonstrates precise antibacterial action around implants (reach an antibacterial ratio of 99.52%). The synergetic locking function of cell membrane and pTA delays BP biodegradation, ensuring favorable photothermal stability and long-term osteo-inductive performance (increasing the bone volume fraction by 53.45%). Beyond providing an endogenic biointerface, this strategy extends the application of cell membrane in local thermal management, offering possibilities for effective and safe PTT modalities.

Antibacterial Activity of Zinc Oxide Nanoparticles Synthesized by Green Eichhornia Crassipes Extract Method

Purpose: Zinc Oxide Nanoparticle (ZnO NPs) production has become more common because of the benefits of the green strategy, which include its ease of use, environmental friendliness, and cheap operating costs. In order to accomplish the goal of green chemistry, the green synthesis process also uses safe solvents like water and ethanol. ZnO NPs are among the metal oxide-NPs used in antibacterial and bioremediation applications. Materials and Methods: Energy Dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared spectroscopy (FT-IR), X-Ray Diffractometer (XRD), and Field Emission Scanning Electron Microscopy (FESEM) were used to analyze the green-produced ZnO NPs. Results: ZnO nanoparticles have an average size of 22.89 nm, which is corroborated by FESEM pictures, indicating that the particles are tiny. The excellent purity of ZnO NPs has been confirmed by EDX data. The antibacterial activity of ZnO NPs was assessed against a few dangerous pathogens. Zinc oxide nanoparticles were shown to have an interesting antibacterial action against both gram-positive and gram-negative bacteria at micromolar concentrations because they exhibit the maximum diameter of inhibition zone at concentrations 100 mg/ml of S. aureus, E. coli, K. pneumonia, Acintobacret spp, S. fecalis reaching (27,19,18,17, and 14) mm, respectively while S. pneumonia were resistant.The ZnO NPs recorded at a concentration of 12.5 mg/ml lowest areas of the inhibition zone against the same isolates reaching (16, 11, 11, 12, and 10) mm while S. pneumonia were resistant, respectively, as well. Conclusion: ZnO NPs, since they have excellent antibacterial properties, and are biocompatible, they will open up a new line of inquiry for antibacterial agent research because they are stable, nontoxic, and harmless.

Activity antibacterial from honey kelulut (Trigona sp.) against bacteria Staphylococcus epidermidis

Honey kelulut is derived from the kelulut bee (Trigona sp.), which is native to Kalimantan and belongs to the Trigona genus of stingless bees. The honey produced by the Trigona genus has a well-documented antibacterial property. Study objective accomplished. This text discusses the potent antibacterial action of kelulut honey. The antibacterial testing method employed is the well diffusion method, utilizing the bacterium Staphylococcus epidermidis as the test organism. An antibacterial test was conducted by measuring the diameter of the zone of inhibition against bacteria. The results were obtained from concentrations of 40%, 60%, 80%, and 100%. Then the resistance diameter was measured for each concentration. The most optimal outcomes were achieved in the antibacterial test using honey kelulut. The honey kelulut with an 80% concentration exhibited a medium resistance level of 10.2 mm, while the 100% concentration demonstrated a strong resistance level of 13.7 mm.

Dye degradation and antimicrobial efficacy of cesium-doped Y2O3 nanostructures: in silico docking study.

Developing multifunctional nanomaterials is crucial to rising global concerns over environmental contamination caused by dye effluents and antibiotic resistance. This work presents cesium (Cs)-doped Y2O3 nanostructures (NSs) as viable options for catalytic dye degradation and antibacterial action. This study prepared yttrium oxide (Y2O3) and various (2, 4, and 6 wt%) concentrations of Cs-doped Y2O3 NSs via co-precipitation technique. The pure and Cs-doped Y2O3 NSs were used to degrade methylene blue (MB) at different pH levels and assess the antibacterial properties against multidrug-resistant (MDR) Escherichia coli (E. coli). The X-ray diffraction spectra of the pure and Cs-doped Y2O3 revealed the presence of cubic and monoclinic structures. The UV-vis absorption spectra displayed distinct peaks at 274 nm and a reduction in band gap energy (from 4.94 eV to 4.41 eV) upon incorporation of Cs. Maximum degradation efficiency of up to 99% attributed to 6% Cs-doped Y2O3. The bactericidal activity against MDR E. coli exhibited 4.15 mm inhibition zones at higher concentrations of Cs-doped Y2O3. The bactericidal mechanism of Cs-Y2O3 NSs was further investigated by molecular docking studies for β-lactamase and DNA gyrase enzymes.

Quercetin, the Potential Powerful Flavonoid for Human and Food: A Review

Flavonoids occur naturally in different types of fruits and vegetables, including tea, cabbage, cauliflower, elderberries, cranberries, red apples, lettuce, pears, spinach, green hot peppers, white and red onions, kale, blueberries, and nuts. Among these flavonoids is quercetin, a potent natural antioxidant and cytotoxic substance with a number of therapeutic functions. Nowadays, quercetin is a common ingredient in many nutraceutical and cosmeceutical products due to its antioxidant properties. Its antibacterial effects and possible action mechanisms have been explored in many studies. From these, it has been established that quercetin stops the activity of numerous Gram-negative and -positive bacteria, fungi, and viruses. This review clarifies the plant sources and extraction methods of quercetin, as well as its medicinal applications as an antibacterial, antifungal, antiviral, and antioxidant agent, with a particular emphasis on the underlying mechanisms of its biological activity. The mechanism of its antimicrobial effect involves damaging the cell membrane—e.g., by changing its permeability, preventing biofilm formation, reducing the mitochondrial expression of virulence factors, and inhibiting protein and nucleic-acid synthesis. Moreover, quercetin has been shown to impede the activity of a variety of drug-resistant bacterial strains, pointing to the possibility of using it as a strong antimicrobial substance against such strains. In addition, it has occasionally been demonstrated that specific structural alterations to quercetin can increase its antibacterial action in comparison to the parent molecule. Overall, this review synthesizes our understanding of the mode of action of quercetin and its prospects for use as a therapeutic material.

Effect of zinc oxide-eugenol endodontic paste on planktonic aggregates and biofilm of Enterococcus faecalis - An atomic force microscopy evaluation

ObjectiveThis work aimed to evaluate the in vitro effect of zinc oxide-eugenol paste (ZOE) on planktonic aggregates (EfPA) and biofilm (EfBio) of Enterococcus faecalis, focusing on their morphological aspects observed and analyzed using atomic force microscopy (AFM). DesignThe eugenol and paste were characterized by Gas Chromatography coupled with Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. The effect of ZOE on EfPA and EfBio was evaluated by a direct-contact test through colony counting and crystal violet staining protocol. AFM images of untreated and treated EfPA and EfBio growth on bovine dentin were obtained to analyze the morphological damage caused by the treatments. ResultsThe characterization showed high purity in the eugenol composition and chemical interaction between the components of the paste. A bactericidal effect on aggregates was observed after 6 h of exposure, and on biofilm after 24 h of treatment (p < 0.001). A disruptive effect on the biofilm was also evident. AFM images revealed the formation of EfPA, with a notable presence of an exopolysaccharide matrix. After 6 h of ZOE treatment, there was a significant increase in the size and surface roughness profile of treated cells (p < 0.05). Loss of typical cell morphology was observed after 24 h. The effect on the biofilm showed a tendency towards a less condensed biofilm pattern in the treated group, with no differences in surface roughness. ConclusionZOE presents bactericidal action on EfPA and EfBio, promoting significant morphological changes after treatment, especially in the aggregates.

Trivalent transition metal ion mediated template synthesis: In silico molecular docking, DNA binding, antimicrobial evaluation and DFT studies

In order to reduce the chances of multiple drug resistance, there is an urgent requirement for the designing of new antimicrobial agents. In this current research, series of novel hexaazamacrocyclic trivalent transition metal complexes of ChromiumIII and IronIII have been prepared by adopting the pathway of metal ion mediated template condensation. The newly synthesized macrocyclic complexes were analyzed by Infra-Red Spectroscopy, Carbon-Hydrogen-Nitrogen analyzer, UltraViolet–visible, Powder X-Ray Diffraction, Electron Paramagnetic Resonance, Magnetic Susceptibilities, Molar conductance, Electron Spray Ionisation-Mass Spectrometry and Thermogravimetric analysis techniques. The electro-lytic behaviour of the complexes was suggested by conductance (molar) values. All the complexes (T7-T12) can be formulated or represented as [MLX] X2·yH2O, where M = FeIII, CrIII and L is the macrocyclic ring resulting from 1,8-diaminonaphthalene and succinimide and X = NO3−, Cl−, CH3COO− and y = 1 or 2. All the macrocyclic complexes have been anticipated to have a penta coordinated square pyramidal shape using several physico-analytical approaches. Monomeric nature of the complexes was confirmed by CHN analysis and mass spectral data. Powder X-Ray Diffraction studies were carried out for interpreting the crystallinity of the complexes. Density Functional Theory studies were performed for energy optimization and theoretical calculations of UV & IR. The DNA interaction studies showed intercalative mode of binding is present in the newly designed complexes with the DNA. In addition to these, all the metal complexes were screened for their antibacterial and antifungal activity against pathogenic strains of bacteria and fungi, Complex T7 has effective bactericidal action against B. cereus and E. coli. Molecular docking studies were also performed on SARS Cov-2 and Mycobacterium tuberculosis. The used proteins are NSP15 Endoribonuclease from SARS CoV-2 and DNA of Mycobacterium tuberculosis H37Rv. The results revealed that complex T10 is having good binding affinity against DNA of Mycobacterium tuberculosis H37Rv.

Viable Bacteria Assay of Helicobacter pylori by RT-qPCR Measurement of cgt Gene Expression Levels: Establishment and Application of a New Method

To establish a viable bacteria assay for Helicobacter pylori (H. pylori) by assessing the cgt gene expression, and to develop accordingly a rapid and novel testing method for clinical precision treatment. Viable bacteria count was determined in bacterial cultures. The transcriptional expression level of cgt (hp0421), the conserved gene that encodes cholesterol-α-glucosyltransferase (CGT) in H. pylori, was measured by RT-PCR. The correlation between the number of colonies and cgt gene transcription expression was analyzed and the regression model was constructed. The linear range, sensitivity, and specificity of the new method were examined accordingly. The bactericidal action of clarithromycin was assessed using this method to verify the performance of the method in determining clinical bacterial drug resistance. The Ct values of cgt for H. pylori colony counts of 102, 104, 106, and 108 CFU/mL were 29.67±0.14, 23.37±0.36, 17.65±0.37, and 11.38±0.39, respectively. In the range of 101-108 CFU/mL, the regression equation for cgt gene expression and viable bacterial counts determined by RT-qPCR was y=-0.3501x+12.49, with the correlation coefficient being R 2=0.9992 and the sensitivity being 101 CFU/mL, showing no cross-reaction with 13 other bacteria. The lg values of live H. pylori bacteria treated with clarithromycin at 0, 5, 10, 20, and 40 μg/mL for 12 h were 2.57±0.02, 2.45±0.01, 2.19±0.02, 1.91±0.07, and 1.33±0.05, respectively. The corresponding cgt gene Ct values were 27.76±0.09, 28.37±0.24, 29.51±0.14, 30.11±0.12, and 31.66±0.11. By applying the cgt gene expression in the equation, the estimated counts of viable bacteria were found to be 2.73±0.03, 2.52±0.08, 2.11±0.05, 1.89±0.02, and 1.33±0.04, showing no significant difference in statistical analysis (P>0.05). The method for assessing viable bacteria account by evaluating cgt gene expression in H. pylori was successfully established, significantly reducing the time required to determine viable bacteria count and providing a new method for clinical viable bacteria testing.

Investigating the Efficacy of Various Natural Products in Raw Form against Multidrug-Resistant Bacteria.

The alarming increase in antibiotic resistance urges alternative and efficacious antimicrobial solutions. Historically, medicinal plants have been used for therapeutic purposes, such as relieving pain and healing wounds. However, the evaluation of the natural therapeutic effects of medicinal plants in a manner that resembles how humans typically consume them is lacking. Therefore, in this study, many medicinal plants known to have some antimicrobial effects, including Frankincense, Garlic, Myrrh, and Ginger, were evaluated for their direct antibacterial activity in raw form. The direct antimicrobial activity of medicinal plants was evaluated against a variety of Gram-positive and Gram-negative bacterial strains, such as Staphylococcus aureus (S. Aureus), Acinetobacter baumannii and Klebsiella pneumoniae using agar well diffusion method and turbidity measurements in suspension culture. Out of all the tested medicinal plants, only raw garlic (Allium sativum) powder, when dissolved in water or vinegar, offered a straightforward antibacterial activity. A combination of garlic extract and vinegar increased antibacterial activity. Aqueous garlic extracts displayed robust antimicrobial activity against many resistant bacteria. Other medicinal plants used in this study had absent or minimal antibacterial effects. Only garlic in its raw form was effective against antibiotic-resistant bacteria. The increase in the antibacterial activity of garlic when combined with vinegar suggests the synergistic activity of garlic. The straightforward antibacterial action of raw garlic may be strategically harnessed to combat the continuous challenge of increasing antibiotic resistance. This work promotes additional testing of more natural products (in raw form) and assesses their therapeutic effects clinically.

Impact of nitric oxide donors on capsule, biofilm and resistance profiles of Klebsiella pneumoniae

Klebsiella pneumoniae is considered to be a critical public health threat due to its ability to cause fatal, multi-drug-resistant infections in the bloodstream and key organs. The polysaccharide-based capsule layer that shields K. pneumoniae from clearance via innate immunity is a prominent virulence factor. K. pneumoniae also forms biofilms on biotic and abiotic surfaces. These biofilms significantly reduce penetration by, and antibacterial activity from, traditional antibiotics. Nitric oxide (NO), an endogenous molecule involved in the innate immune system, is equally effective at eradicating bacteria but without engendering resistance. This study investigated the effects of NO-releasing small molecules capable of diverse release kinetics on the capsule and biofilm formation characteristics of multiple K. pneumoniae strains. The use of NO donors with moderate and extended NO-release properties (i.e., half-life >1.8 h) inhibited bacterial growth. Additionally, treatment with NO decreased capsule mucoviscosity in K. pneumoniae strains that normally exhibit hypermucoviscosity. The NO donors were also effective against K. pneumoniae biofilms at the same minimum biocidal concentrations that eliminated planktonic bacteria, while meropenem showed little antibacterial action in the same experiments. These results represent the first account of exogenous NO affecting biomarkers involved in K. pneumoniae infections, and may therefore inform future development of NO-based therapeutics for treating such infections.