Gram-positive Bacterial Strains Research Articles

Synthesis, Antioxidant and Antimicrobial Activity of Calix[4]Arene Acetanilide Derivative

The current work explores the antioxidant and antimicrobial activity of a newly synthesized calix[4] arene acetanilide derivative (3), which was synthesized through Mannich reaction by the treatment of calix[4] arene with acetanilide, formaldehyde and acetic acid in tetrahydrofuran, The antioxidant activity was determined by using DPPH method. Results show that the new synthesized compound 3 has good antioxidant activity. The antimicrobial activity of 3 was staunched against different types of microorganisms, i.e. gram-negative and gram-positive bacterial strains (Escherichia Coli ATCC 8739 and Staphylococcus Aureus ATCC 10231) along with a fungus (Aspergillus Niger ATCC 16405). A suitable agar medium (Mueller Hinton agar) was applied for the growth of microorganisms. Kirby-Bauer well agar diffusion method was used to check the antimicrobial activity. The bacterial strains zone has been observed in between 250–4000 µg/ml. It is noticed that compound 3 has very good effect against fungus A niger as compared to bacterial strains. Its minimum inhibitory concentration (MIC) against A. niger, S. aureus and E. coli is found to be 250, 500 and 1000 µg/mL, respectively. Consequently, the study has been compared with the reported calix[4] arene derivatives and it has been revealed that the compound 3 is a good antimicrobial agent. Hence, it could be inferred that compound 3 is considerably effective against selected microorganisms and may be used as a medicine in near future and beneficial for the human.

6-Polyaminosteroid Squalamine Analogues Display Antibacterial Activity against Resistant Pathogens.

A series of 6-polyaminosteroid analogues of squalamine were synthesized with moderate to good yields and evaluated for their in vitro antimicrobial properties against both susceptible and resistant Gram-positive (vancomycin-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus) and Gram-negative (carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa) bacterial strains. Minimum inhibitory concentrations against Gram-positive bacteria ranged from 4 to 16 µg/mL for the most effective compounds, 4k and 4n, and showed an additive or synergistic effect with vancomycin or oxacillin. On the other hand, the derivative 4f, which carries a spermine moiety like that of the natural trodusquemine molecule, was found to be the most active derivative against all the resistant Gram-negative bacteria tested, with an MIC value of 16 µg/mL. Our results suggest that 6-polyaminosteroid analogues of squalamine are interesting candidates for Gram-positive bacterial infection treatments, as well as potent adjuvants to fight Gram-negative bacterial resistance.

Ecofriendly green synthesis and characterization of silver zinc oxide nanocomposite using the aqueous leaf extract of Rumex Crispus: Evaluation of its antimicrobial and antioxidant activity

The hydrothermal approach is used in the current study to create an environmentally friendly silver zinc oxide nanocomposite utilizing an aqueous leaf extract of Rumex Crispus. The photochemical components of Rumex Crispus, a synthetic nanocomposite with antioxidant and antibacterial activity, were also assessed. The Response Surface Methodology of Definitive Screen Design (DSD) was used to examine and optimize the effects of four independent variables on the amount of green synthesized silver zinc oxide nanocomposite in Rumex Crispus extract. According to the experimental findings, the green synthesized silver zinc oxide nanocomposite's maximum 1.89 absorbance intensity was achieved at a reaction temperature of 60 °C, a concentration of silver nitrate salt of 100 mM, a pH value of 11, and a reaction period of 3 h. The synthesized nanocomposite was characterized using Fourier-transform infrared, UV, X-ray, UV–vis, Dynamic Light Scattering, thermogravimetric analysis, and differential thermal analysis to determine its functional group, structure, bandgap energy, size distribution, a mass of loss, and energy gain or loss, respectively. The minimum lethal doses for the gram-positive, gram-negative, and fungal strains were 1.25, 0.625, and 2.5 g ml−1 respectively. The 1-1-diphenyl-2-picryl hydrazyl (DPPH) which was used to measure antioxidant activity is scavenged by Ag–ZnO nanocomposites, and the IC50 value of a Rumex Crispus extract is 29.31 g ml-1 IC50 value is.29.31 μg ml–1. Their findings show that Rumex Crispus extract-derived synthetic silver zinc oxide nanocomposite is a promising alternative against both Gram-positive and Gram-negative bacterial strains and fungal strains, as well as a prospective choice for antioxidants under the given conditions.

Evaluation of Biological Activity of New 1,2,4-Triazole Derivatives Containing Propionic Acid Moiety.

To this day, the quest to find new drugs is still a challenge due to the growing demands of patients suffering from chronic inflammatory diseases and the need for the individualization of therapy. The aim of this research was to synthesize new 1,2,4-triazole derivatives containing propanoic acid moiety and to investigate their anti-inflammatory, antibacterial and anthelmintic activity. Compounds 3a-3g were obtained in reactions of amidrazones 1a-1g with succinic anhydride. Several analyses of proton and carbon nuclear magnetic resonance (1H NMR, 13C NMR, respectively), as well as high-resolution mass spectra (HRMS), confirmed the structures of 1,2,4-triazole derivatives 3a-3g. Toxicity, antiproliferative activity and influence on cytokine release (TNF-α: Tumor Necrosis Factor-α, IL-6: Interleukin-6, IFN-γ: Interferon-γ, and IL-10: Interleukin-10) of the compounds 3a-3g were evaluated in peripheral blood mononuclear cells culture. Moreover, mitogen-stimulated cell culture was used for biological activity tests. The antimicrobial and anthelmintic activity of derivatives 3a-3g were studied against Gram-positive and Gram-negative bacterial strains and Rhabditis sp. culture. Despite the lack of toxicity, compounds 3a-3g significantly reduced the level of TNF-α. Derivatives 3a, 3c and 3e also decreased the release of IFN-γ. Taking all of the results into consideration, compounds 3a, 3c and 3e show the most beneficial anti-inflammatory effects.

Biologically Reduced Zinc Oxide Nanosheets Using Phyllanthus emblica Plant Extract for Antibacterial and Dye Degradation Studies

The nanostructures synthesized using the green chemistry method have recently attracted the attention of scientists due to their significance in many scientific domains. This work provides an overview of the biosynthesis of zinc oxide (ZnO) nanosheets (NSs) using Phyllanthus emblica plant (PEP) extract. X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) were used to analyze the synthesized ZnO-NSs. Evaluation of the antibacterial activity of biosynthesized ZnO-NSs was performed. ZnO-NSs exhibit effective antibacterial activity against Gram-positive (S. pyogenes and S. aureus) and Gram-negative (S. typhi and E. coli) bacterial strains. S. typhi is the most sensitive microbe towards ZnO-NSs and formed a 21 mm zone of inhibition (ZOI). ZnO-NSs are also tested as a photocatalyst in the degradation of methyl orange (MO) and rhodamine B (RB). The degradation rate of MO was 90%, and RB was 96% after being exposed to UV light for 120 min. The as-synthesized ZnO-NSs exhibited selective dye degradation and showed relatively better photocatalytic activity for positively charged (cationic) dyes. This work could lead to the fabrication of high-yield photocatalysts, which have the potential to degrade textile dyes from aqueous solution.

Antimicrobial Diterpenes from Rough Goldenrod (Solidago rugosa Mill.).

Solidago rugosa is one of the goldenrod species native to North America but has sporadically naturalized as an alien plant in Europe. The investigation of the root and leaf ethanol extracts of the plant using a bioassay-guided process with an anti-Bacillus assay resulted in the isolation of two antimicrobial components. Structure elucidation was performed based on high-resolution tandem mass spectrometric and one- and two-dimensional NMR spectroscopic analyses that revealed (-)-hardwickiic acid (Compound 1) and (-)-abietic acid (Compound 2). The isolates were evaluated for their antimicrobial properties against several plant pathogenic bacterial and fungal strains. Both compounds demonstrated an antibacterial effect, especially against Gram-positive bacterial strains (Bacillus spizizenii, Clavibacter michiganensis subsp. michiganensis, and Curtobacterium flaccumfaciens pv. flaccumfaciens) with half maximal inhibitory concentration (IC50) between 1 and 5.1 µg/mL (5-20 times higher than that of the positive control gentamicin). In the used concentrations, minimal bactericidal concentration (MBC) was reached only against the non-pathogen B. spizizenii. Besides their activity against Fusarium avenaceum, the highest antifungal activity was observed for Compound 1 against Bipolaris sorokiniana with an IC50 of 3.8 µg/mL.

Characterization of the Bacterial Communities Inhabiting Tropical Propolis of Puerto Rico.

Propolis is a resinous material produced by honeybees from different plant sources and used in the hive as a building material and to protect the colony from parasites and pathogens. Despite its antimicrobial properties, recent studies showed that propolis hosts diverse microbial strains, some with great antimicrobial potential. In this study, the first description of the bacterial community of propolis produced by the gentle Africanized honeybee was reported. Propolis was sampled from hives of two different geographic areas of Puerto Rico (PR, USA), and the associated microbiota investigated by both cultivation and metataxonomic approaches. Metabarcoding analysis showed appreciable bacterial diversity in both areas and statistically significant dissimilarity in the taxa composition of the two areas, probably due to the different climatic conditions. Both metabarcoding and cultivation data revealed the presence of taxa already detected in other hive components and compatible with the bee's foraging environment. Isolated bacteria and propolis extracts showed antimicrobial activity against Gram-positive and Gram-negative bacterial tester strains. These results support the hypothesis that the propolis microbiota could contribute to propolis' antimicrobial properties.

Novel arylazo nicotinate derivatives as effective antibacterial agents: Green synthesis, molecular modeling, and structure-activity relationship studies

A series of novel arylazo nicotinates compounds, denoted as (3a-k and 5a-d) were synthesized and characterized through the reaction of 3-oxo-arylhydrazonals with various active methylene nitriles using microporous zeolite as a green catalyst. The structure of the newly prepared heterocycles was determined using various spectral techniques such as MS, IR, NMR, and elemental analysis. The antibacterial activity of these compounds against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) was evaluated, and it was found that all arylazo nicotinate compounds were highly effective against both gram-negative (E. coli) and gram-positive (B. subtilis) bacterial strains. The efficacy of the developed arylazo nicotinate derivatives as antimicrobial agents against E. coli and B. subtilis was evaluated using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Density-functional theory (DFT) was employed to investigate the structure–activity relationships of recently synthesized compounds. Gaussian 09 software was utilized to compute various molecular properties, including the distribution of frontier molecular orbitals (FMO), the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), the energy gap (Eg), as well as several biological activity descriptors such as ionization potential (IP), electron affinity (EA), chemical potential (μ), chemical hardness (η), electronegativity (χ), global softness (S), and electrophilicity index (ω). The results of the FMO calculations revealed that the arylazo nicotinates had effective charge separation and distinct HOMO/LUMO energy levels for each compound, as reflected by the different Eg values. The Eg values were found to have a strong correlation with the antibacterial efficacy against E. coli and B. subtilis. The highest and lowest efficacy among the molecules (3a-k) were observed for compounds 3b (Eg = 3.36 eV) and 3 k (Eg = 2.27 eV), respectively, while the highest and lowest efficacy among the molecules (5a-d) were observed for compounds 5d (Eg = 3.33 eV) and 5c (Eg = 2.94 eV), respectively.

Cover Feature: Polypyridyl CoII‐Curcumin Complexes as Photoactivated Anticancer and Antibacterial Agents (ChemBioChem 10/2023)

Visible light-induced anticancer and antibacterial profiles of Co(II) curcumin complexes. This cover illustrates Co(II)-curcumin conjugates exhibiting remarkable visible light-triggered anticancer activity against breast cancer (MCF-7) cells by ROS-induced apoptosis and the fluorescent nature of curcumin assisting in cell imaging. Also, antibacterial activity against both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial strains through the activation of the Co(II)-curcumin conjugates at the targeted site by light exposure, is depicted here. More information can be found in the Research Article by B. Koch, S. Banerjee.

In vitro and in silico study of the biological activity of tetradentate Schiff base copper(II) complexes with ethylenediamine-bridge

The biological activity of six structurally similar tetradentate Schiff base copper(II) complexes, namely [Cu(ethylenediamine-bis-acetylacetonate)] (CuAA) and five derivatives where two methyl groups are replaced by phenyl, (CuPP), CF3 (CuTT) or by mixed groups CH3/CF3 (CuAT), Ph/CF3 (CuPT), and Ph/CH3 (CuAP) has been investigated. The set of antioxidant assays was performed, and the results were expressed as IC50 and EC50 values. The series of complexes showed interesting bioactivity and were investigated for the determination of antioxidant, antifungal, antimicrobial, and cytotoxic activity. A significant antioxidant behavior was exhibited by complex CuAA, greater than Trolox in the Oxygen Radical Absorbance Capacity (ORAC) assay. Antibacterial assay over Gram-positive and Gram-negative pathogenic bacterial strains and some fungal pathogens were studied. Antiproliferative activity of complexes in two human tumor cell lines, breast adenocarcinoma MCF-7, colon adenocarcinoma LS-174, and normal fibroblast cells-MRC-5, examined the effect on cell cycle progression. The significant cytotoxic potential, comparable to cisplatin cytotoxicity, was determined in human breast cancer cell line-MCF-7 with IC50 values being 17.53–31.40 μM and human colon cancer cell line-LS-174 with IC50 values being 15.22–23.92 μM. All tested compounds showed nearly twice more selectivity toward cancer cell lines than normal cells. The interactions of complexes with human serum albumin (HSA), the most prominent protein in plasma, were investigated using spectroscopic fluorescence techniques. The complexes bind to human serum albumin at multiple sites (n = 0.2–1.9), displaying a moderate binding constant Ka = 4.1–12.4 × 104 M−1. The molecular docking experiment effectively showed complex binding to HSA and DNA molecular fragments.

Antimicrobial effect of pimozide by targeting ROS-mediated killing in Staphylococcus aureus.

In spite of the higher nosocomial and community-acquired infections caused by Staphylococcus aureus, emerging drug resistance is a leading cause of increased mortality and morbidity associated with the overuse of antimicrobials. It is an emergent need to find out new molecules to combat such infections. In the present study, we analyzed the antibacterial effect of pimozide (PMZ) against gram-positive and gram-negative bacterial strains, including methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) S. aureus. The growth of MSSA and MRSA was completely inhibited at concentrations of 12.5 and 100μg/mL, respectively, which is referred to as 1× minimum inhibitory concentration (MIC). The cell viability was completely eliminated within 90min of PMZ treatment (2× MIC) through reactive oxygen species (ROS)-mediated killing without affecting cell membrane permeability. It suppressed α-hemolysin production and biofilm formation of different S. aureus strains by almost 50% at 1× MIC concentration, and was found to detach matured biofilm. PMZ treatment effectively eliminates S. aureus infection in Caenorhabditis elegans and improves its survival by 90% and is found safe to use with no hemolytic effect on human and chicken blood tissues. Taken together, it is concluded that PMZ may turn out to be an effective antibacterial for treating bacterial infections including MSSA and MRSA.

Biopolymer Chitosan Surface Engineering with Magnesium Oxide-Pluronic-F127-Escin Nanoparticles on Human Breast Carcinoma Cell Line and Microbial Strains.

Nanotechnology has been recognized as a highly interdisciplinary field of the twenty-first century, with diverse applications in biotechnology, healthcare, and material science. One of the most commonly employed non-toxic nanoparticles, magnesium oxide nanoparticles (MgO NPs), is simple, inexpensive, biocompatible, and biodegradable. Several researchers are interested in the biosynthesis process of MgO NPs through chemical and physical approaches. This is because of their simplicity, affordability, and environmental safety. In the current study, green MgO-Chitosan-Pluronic F127-Escin (MCsPFE) NPs have been synthesized and characterized via various techniques like UV-visible, Fourier-transform infrared spectroscopy, Energy dispersive X-ray composition analysis, Transmission electron microscopy, field emission scanning electron microscopy, X-ray Diffraction, Photoluminescence, and Dynamic light scattering analyses. The average crystallite size of MCsPFE NPs was 46 nm, and a face-centered cubic crystalline structure was observed. Further, the antimicrobial effectiveness of NPs against diverse pathogens has been assessed. The cytotoxic potential of the nanoparticles against MDA-MB-231 cell lines was evaluated using the MTT test, dual AO/EB, JC-1, DCFH-DA, and DAPI staining procedures. High antimicrobial efficacy of MCsPFE NPs against Gram-positive and Gram-negative bacterial strains as well as Candida albicans was observed. The findings concluded that the NPs augmented the ROS levels in the cells and altered the Δψm, leading to the initiation of the intrinsic apoptotic cell death pathway. Thus, green MCsPFE NPs possess immense potential to be employed as an effective antimicrobial and anticancer treatment option.

Synthesis, cytotoxicity and antibacterial activities of ruthenium, rhodium and iridium metal complexes containing diazafluorene functionalized ligands

New structurally related Ru(II), Rh(III) and Ir(III) N∩N chelating complexes of general formula [(arene)M(κ2(N∩N)L)Cl]PF6 (where arene = p-cymene, benzene and Cp*, M = Ru, Rh and Ir and L = 4,5 diazafluorene derivative ligands) have been designed and synthesized. All the complexes have been characterized by physicochemical and spectroscopic methods (FT-IR, NMR, UV, HRMS). The presence of a distorted octahedral geometry around the metal ion was confirmed by single crystal X-ray diffraction studies. The synthesized ligands, along with their metal complexes, were screened for their in-vitro antibacterial activity against two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and two Gram-positive (Bacillus thuringiensis and Staphylococcus aureus) bacterial strains and also for in-vitro antioxidant and cytotoxicity activities. Results of antibacterial activity revealed that the metal complexes possess good antibacterial activity. Cytotoxicity results displayed that the compounds act as potent anticancer agents.

First Report of green Synthesis of Copper Oxide Nanoparticles from Brassica Tournefortii Leaves Extract and Their Antibacterial Activity

In the present study, copper oxide nanoparticles (CuO NPs) were synthesized using a eco-friendly technique and evaluated their antibacterial activity. At the first time, Brassica tournefortii leaves extract mediated copper oxide-based nanoparticles which prepared by a bio-reduction method using an aqueous Brassica tournefortii leaves extract as both a reducing and stabilizing agent. Copper oxide nanoparticles were characterized by using ultraviolet-visible spectroscopy (UV-VIS), Fourier transform-infrared spectroscopy (FT-IR), x-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. The synthesized CuO nanoparticles were also evaluated for their antibacterial activity against gram-positive (Staphylococcus aureus and Streptococcus spp) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial strains. UV-Vis and FT-IR

Physicochemical and microbiological characterization of olive oil mill wastewater (OMWW) from Algerian Sahara, region of Ghardaia

The aims of this study were to determine the physical-chemical and microbiologicalcharacteristics of olive oil mill wastewater (OMWW) resulting from the extraction of olive oil inAlgerian Sahara in Ghardaia region, and to evaluate the antibacterial activity of the OMWWextracts manifested by their phenolic compounds on the identified bacteria. This is the first studyof physicochemical and microbiological characterization of the olive mill wastewater resulting fromthe modern industrial unit of trituration of olives by three-phases centrifugation in Ghardaia re-gion in Algerian Sahara. The results showed that this effluent is too rich in organic matter thatis expressed by BOD5 and COD. It is also characterized by an acidic pH (4.8) and a high level ofphenolic compounds. The microbiological study of the olive oil mill wastewater showed the isola-tion of three GRAM positive bacterial strains (Staphylococcus aureus, Staphylococcus epidermidisand Bacillus subtilis ) and five fungal strains (Penicillium sp, Aspergillus ochraceus, Aspergillus fu-migatus, Penicillium chrysogenum and Aspergillus niger ), and one strain of yeast Saccharomycescerevisiae. The results of the antibacterial activity showed that strains which were isolated fromthe olive oil mill wastewater were resistant to the phenolic compounds whereas clinical strains weresensitive.

Antioxidant and Antimicrobial Effects of Nannorrhops baluchestanica: An Endemic Palm Species in Southeast Iran

Background: Nannorrhops baluchestanica Khodash is a recently introduced shrubby species belonging to the family Arecaceae, distributed in Southeast Iran. Objectives: The antioxidant and antimicrobial potentials of this endemic plant were studied. Methods: The seeds and fruits of N. baluchestanica were collected from a natural population in Shark village, and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity of their hydroethanolic extracts was evaluated to determine potential antioxidant properties. In addition, inhibitory, bactericidal, and fungicidal effects of seed and fruit hydroalcoholic extracts were studied against a variety of pathogens, including three fungal strains (Aspergillus fumigatus, Fusarium oxysporum, and Candida albicans), three Gram-negative (klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli), and three Gram-positive bacterial strains (Bacillus cereus, Staphylococcus epidermidis, and Streptococcus pyogenes) via broth microdilution and streak plate methods. Results: The IC50 values of 26.20 and 33.90 µg.mL-1 were calculated for the fruit and seed extracts, respectively, using vitamin E with IC50 of 10.40 as standard. The MIC, MBC, and MFC values ranged from 128 to 2048 μg.mL-1. The fruit extract inhibited the growth of all microbial strains except for B. cereus and S. epidermidis, while P. aeruginosa and F. oxysporum were the only strains inhibited by the seed extract. In agreement with antioxidant properties, more broad-spectrum antimicrobial effects were observed in the fruit extract. Conclusions: Excellent antioxidant capacities of N. baluchestanica extracts indicate their great potential for treatment or prevention of oxidative stress-related diseases, but only slight effectiveness against infectious agents was observed.

Synthesis and characterization of natural deep eutectic solvents as green extractants for isolation of bioactive flavonoids from Amaranthus viridis

The application of principles of Green Chemistry is gaining importance in various fields of research to eliminate the risk of environmental pollution from toxic chemicals. Safer industrial processes reduce the risk of health problems to the consumers as well as result in a sustainable and cleaner environment. This paper indicated the synthesis of sustainable green solvents having greater solvation property to extract phytochemicals from plants in comparison to an organic solvent. Natural deep eutectic solvents (NADES) containing choline chloride (ChCl), 1,2-propanediol (PG) and citric acid (CA) were prepared followed by the study of its physicochemical properties. Selected NADES's were then used for the first time to extract bioactive components from Amaranthus viridis (AV) and compared with the ethanolic extract. The results indicated the total phenolic content (TPC) value of 54.6, 250, 40.6 mgGAE/g, total flavonoid content value (TFC) of 16.5, 82.1, 20.4 mgQUE/g and antioxidant activity of 30.3, 42.9, 22.6 mg/ml of AV extract in ChCl:PG:H2O-1:2:1 (AV-PG), AV extract in ChCl:CA:H2O-1:1:1 (AV-CA) and AV extract in ethanol (AV-E) respectively. A high concentration of bioactive components in NADES extracts was confirmed by phytochemical analysis comparing to ethanol extract. Antibacterial activity of AV-CA extract showed inhibition zone of 30 mm against both gram-positive and gram-negative bacterial strains. From the results it can be concluded that NADES extracts can be used for biomedical applications as an improvement in the drug delivery system by eliminating the toxic solvents.

Biological Response Evaluation of Human Fetal Osteoblast Cells and Bacterial Cells on Fractal Silver Dendrites for Bone Tissue Engineering.

Prosthetic joint replacement is the most widely used surgical approach to repair large bone defects, although it is often associated with prosthetic joint infection (PJI), caused by biofilm formation. To solve the PJI problem, various approaches have been proposed, including the coating of implantable devices with nanomaterials that exhibit antibacterial activity. Among these, silver nanoparticles (AgNPs) are the most used for biomedical applications, even though their use has been limited by their cytotoxicity. Therefore, several studies have been performed to evaluate the most appropriate AgNPs concentration, size, and shape to avoid cytotoxic effects. Great attention has been focused on Ag nanodendrites, due to their interesting chemical, optical, and biological properties. In this study, we evaluated the biological response of human fetal osteoblastic cells (hFOB) and P. aeruginosa and S. aureus bacteria on fractal silver dendrite substrates produced by silicon-based technology (Si_Ag). In vitro results indicated that hFOB cells cultured for 72 h on the Si_Ag surface display a good cytocompatibility. Investigations using both Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacterial strains incubated on Si_Ag for 24 h show a significant decrease in pathogen viability, more evident for P. aeruginosa than for S. aureus. These findings taken together suggest that fractal silver dendrite could represent an eligible nanomaterial for the coating of implantable medical devices.

Acetylcholine Esterase Inhibitory Effect, Antimicrobial, Antioxidant, Metabolomic Profiling, and an In Silico Study of Non-Polar Extract of The Halotolerant Marine Fungus Penicillium chrysogenum MZ945518.

Major health issues, such as the rise in oxidative stress, incidences of Alzheimer's disease, and infections caused by antibiotic-resistant microbes, have prompted researchers to look for new therapeutics. Microbial extracts are still a good source of novel compounds for biotechnological use. The objective of the current work was to investigate marine fungal bioactive compounds with potential antibacterial, antioxidant, and acetylcholinesterase inhibitory effects. Penicillium chrysogenum strain MZ945518 was isolated from the Mediterranean Sea in Egypt. The fungus was halotolerant with a salt tolerance index of 1.3. The mycelial extract showed antifungal properties against Fusarium solani with an inhibitory percentage of 77.5 ± 0.3, followed by Rhizoctonia solani and Fusarium oxysporum with percentages of 52 ± 0.0 and 40 ± 0.5, respectively. The extract also showed antibacterial activity against both Gram-negative and Gram-positive bacterial strains using the agar diffusion technique. The fungal extract was significantly more effective with Proteus mirabilis ATCC 29906 and Micrococcus luteus ATCC 9341; inhibition zones recorded 20 and 12 mm, respectively, compared with the antibiotic gentamycin, which recorded 12 and 10 mm, respectively. The antioxidant activity of the fungus extract revealed that it successfully scavenged DPPH free radicals and recorded an IC50 of 542.5 µg/mL. Additionally, it was capable of reducing Fe3+ to Fe2+ and exhibiting chelating ability in the metal ion-chelating test. The fungal extract was identified as a crucial inhibitor of acetylcholinesterase with an inhibition percentage of 63% and an IC50 value of 60.87 µg/mL. Using gas chromatography-mass spectrometry (GC/MS), 20 metabolites were detected. The most prevalent ones were (Z)-18-octadec-9-enolide and 1,2-Benzenedicarboxylic acid, with ratios of 36.28 and 26.73%, respectively. An in silico study using molecular docking demonstrated interactions between the major metabolites and the target proteins, including: DNA Gyrase, glutathione S-transferase, and Acetylcholinesterase, confirming the extract's antimicrobial and antioxidant activity. Penicillium chrysogenum MZ945518, a halotolerant strain, has promising bioactive compounds with antibacterial, antioxidant, and acetylcholinesterase inhibitory activities.

Microbacterium tenebrionis sp. nov. and Microbacterium allomyrinae sp. nov., isolated from larvae of Tenebrio molitor L. and Allomyrina dichotoma, respectively.

Two Gram-positive bacterial strains, designated as YMB-B2T and BWT-G7T, were isolated from larvae of Tenebrio molitor L. and Allomyrina dichotoma, respectively, and their taxonomic positions examined by a polyphasic approach. Both of the isolates contained ornithine as the cell-wall diamino acid. The acyl type of murein was N-glycolyl. The predominant menaquinones were MK-11 and MK-12. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol and an unidentified glycolipid. Both of the isolates contained C15 : 0 anteiso and C17 : 0 anteiso as the major fatty acids. Strain YMB-B2T also had C16 : 0 iso as an additional major fatty acid. The 16S rRNA gene phylogeny showed that the novel strains formed two distinct sublines within the genus Microbacterium. Strain YMB-B2T was most closely related to the type strains of Microbacterium aerolatum (99.1 % sequence similarity) and Microbacterium ginsengiterrae (99.0 %), whereas strain BWT-G7T formed a tight cluster with the type strain of Microbacterium thalassium (98.9 %). The phylogenomic analysis based on 92 core genes supported their relationships in 16S rRNA gene phylogeny. Overall genomic relatedness indices warranted that the isolates represent two new species of the genus Microbacterium. Based on the results obtained here, Microbacterium tenebrionis sp. nov. (type strain YMB-B2T=KCTC 49593T=CCM 9151T) and Microbacterium allomyrinae sp. nov. (type strain BWT-G7T=KACC 22262T=NBRC 115127T) are proposed.