Search Results (98)

In this study, a series of novel alkoxylated resorcinarenes were synthesized using secondary and tertiary alcohols under mild catalytic conditions involving iminodiacetic acid. Structural characterization, including single-crystal X-ray diffraction, confirmed the successful incorporation of branched alkyl chains and highlighted the influence of substitution patterns on molecular packing. Notably, detailed mass spectrometric analysis revealed that, under specific conditions, the reaction pathway may shift toward the formation of defined oligomeric species with supramolecular characteristics—an observation that adds a new dimension to the synthetic potential of this system. To complement the chemical analysis, selected derivatives were evaluated for biological activity, focusing on bacterial growth and biofilm formation. Using four clinically relevant strains (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis), we assessed both planktonic proliferation (OD₆₀₀) and biofilm biomass (crystal violet assay). Compound 2c (2-pentanol derivative) consistently promoted biofilm formation, particularly in S. aureus and B. subtilis, while having limited cytotoxic effects. In contrast, compound 2e and the DMSO control exhibited minimal impact on biofilm development. The results suggest that specific structural features of the alkoxy chains may modulate microbial responses, potentially via membrane stress or quorum sensing interference. This work highlights the dual relevance of alkoxylated resorcinarenes as both supramolecular building blocks and modulators of microbial behavior. Full article

Daucus is a large genus of the Apiaceae family, comprising around forty-five accepted species, that has a worldwide distribution. Species of this genus have been reported to have several traditional medicinal uses, and some of them are also largely used as food and spices. Daucus nebrodensis Strobl. is an endemic species of Sicily growing in the montane environments of the Madonie and the Nebrodi Mountains. In this work, the essential oil of D. nebrodensis (DnEO), collected wild near Messina (Italy), was chemically and biologically investigated. The hydrodistilled essential oil (yield 0.15%), obtained from fresh aerial parts, was evaluated by GC-MS, and It was particularly rich in monoterpene hydrocarbons, with sabinene (33.6%), α-pinene (17.2%), γ-terpinene (9.8%), and α-terpinene (7.6%) as the main metabolites. DnEO, and its main constituents, have been tested to evaluate their biological properties. Given the current problem of antibiotic resistance, it is of great interest to identify alternative molecules that could counteract the its progression. Therefore, DnEO was tested against Gram-negative species, such as E. coli DH5α and P. aeruginosa PAOI, and Gram-positive species, such as S. aureus ATCC6538P, B. subtilis AZ54, and M. smegmatis MC²155, showing notable antibacterial activity. The MIC for Bacillus subtilis, the most sensitive strain, was 18 mg/mL, while the MIC for Pseudomonas aeruginosa, the least sensitive strain, was 30 mg/mL. Moreover, interesting antibiofilm activity was observed against Mycobacterium smegmatis with a 55% inhibition. Its ability to form biofilms contributes to its persistence and resistance in clinical settings. These findings highlight the potential of D. nebrodensis EO as a source of bioactive compounds with promising antimicrobial and antibiofilm properties. Full article

Bacteria are the primary microorganisms responsible for nosocomial infections. This study investigates the antibacterial, biofilm-disrupting, and cytotoxic properties of essential oils and their emulsions for the treatment of nosocomial pathogens. The antibacterial activity of selected essential oils and their emulsions was evaluated against clinically relevant strains, including Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Pseudomonas aeruginosa, and Salmonella Enteritidis. Among the tested compounds, cinnamaldehyde exhibited the most potent antibacterial activity, with minimum inhibitory concentrations ranging from 1.31 to 2.62 mg/mL against both Gram-positive and Gram-negative bacteria. Other essential oils, such as cinnamon, eucalyptus, and pine, also demonstrated antibacterial effects, although their efficacy against Pseudomonas aeruginosa was comparatively limited. In biofilm assays, cinnamaldehyde effectively disrupted biofilms formed by S. aureus, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa, indicating its potential for treating biofilm-associated infections. Cytotoxicity testing revealed that while cinnamon essential oil and cinnamaldehyde exhibited cytotoxic effects at concentrations above 0.1%, other essential oils such as basil and eucalyptus were non-toxic at the tested concentrations. These findings suggest that cinnamaldehyde is a promising agent for managing nosocomial infections, combining effective antibacterial and biofilm-disrupting properties with acceptable safety for non-target cells at appropriate doses. Full article

Streptococcus mutans (S. mutans) plays an important role in dental caries through acid production and biofilm formation. The membrane vesicles (MVs) of S. mutans are essential for microbial physiology, biofilm activity, and acid adaptation. The OpuB transporter regulates osmotic pressure in Bacillus subtilis; however, its role in S. mutans and its MVs remains unexplored. This study investigated the effects of the opuB pathway on MV biogenesis, as well as the proteomic and lipidomic profiles under neutral (pH 7.5) and acidic (pH 5.5) conditions. Nanoflow cytometry showed that the opuB-deficient strain (Smu_opuB) produced significantly more and smaller MVs than UA159 at pH 7.5, while the difference was not significant at pH 5.5. Lipidomic analysis revealed that opuB affected the lipid composition and concentration of S. mutans MVs. Proteomic analysis identified the differential enrichment of key metabolic processes associated with stress, including DNA repair. These findings highlight that opuB is an important regulator of MV biosynthesis and composition and may affect the environmental adaptability of S. mutans by regulating MVs. Full article

The potato (Solanum tuberosum), an important component of global food security, often faces threats from various diseases during its growth process, especially potato anthracnose (Colletotrichum coccodes), which severely affects crop yield and quality. In this study, we successfully isolated and identified two bacteria with potential for biological control, (Pantoea agglomerans) and (Bacillus subtilis). The experimental results indicate that the bacterial suspensions of strains JZ-1-1-1 and JZ-2-2-2 had a significant inhibitory effect on the pathogen ZL-7, with the inhibition rate of JZ-1-1-1 reaching as high as 55.21%. The inhibition rate of JZ-2-2-2 was 53.48%. When these two strains were mixed at a 4:6 ratio, the inhibitory effect on pathogenic bacteria was even more significant, reaching 68.58% inhibition. In addition, the composite microbial community produced biofilms with their yield gradually increasing within 24 h and showing a slight decrease after 72 h. The efficacy test further indicated that the composite bacterial suspension was highly effective in controlling the spread of lesions, with an efficacy rate as high as 81.40%. In the analysis of defense enzyme activity, peroxidase (POD) and superoxide dismutase (SOD) levels peaked on day seven, while the composite bacterial suspension significantly reduced malondialdehyde (MDA) and polyphenol oxidase (PPO) activity. Quantitative real-time PCR confirmed that these two strains effectively colonized the surface of potato tubers. In summary, this study provides an important theoretical basis and practical guidance for the application of biological methods for the prevention and control of potato anthracnose. Full article

Bone tissue engineering aims to develop biomaterials that are capable of effectively repairing and regenerating damaged bone tissue. Among the various polymers used in this field, polycaprolactone (PCL) is one of the most widely utilized. As a biocompatible polymer, PCL is easy to fabricate, cost-effective, and offers consistent quality control, making it a popular choice for biomedical applications. However, PCL lacks inherent antibacterial properties, making it susceptible to bacterial adhesion and biofilm formation, which can lead to implant failure. To address this issue, this study aims to enhance the antibacterial properties of PCL by incorporating calcium phosphate composite (PCL_CaP) nanostructures onto its surface via hydrothermal synthesis. The resulting “PCL_CaP” nanostructured surfaces exhibited improved wettability and demonstrated mechano-bactericidal potential against Escherichia coli and Bacillus subtilis. The flake-like morphology of the fabricated CaP nanostructures effectively disrupted bacteria membranes, inhibiting bacterial growth. Furthermore, the “PCL_CaP” surfaces supported the adhesion, proliferation, and differentiation of pre-osteoblasts, indicating their potential for bone tissue engineering applications. This study demonstrates the promise of calcium phosphate composite nanostructures as an effective antibacterial coating for implants and medical devices, with further research required to evaluate their long-term stability and in vivo performance. Full article

Plasma-treated water (PTW) recently entered science as a sanitizing agent, which possess the capability for on-demand production. It offers interesting possibilities for sustainable and resource-saving applications in healthcare and food production. The present study monitors the impact of PTW on suspended cells before the biofilm formation of the putrefactive bacterium B. subtilis. Light and electron microscope imaging captures the maturing of growing biofilms within the first 24 h. Microbiological assays (proliferation, LIVE/DEAD, and XTT), which mirror the proliferation of the bacterium, the metabolic activity, and the integrity of the cell membrane, underpinning the metabolic response of still-suspended cells. B. subtilis cells without any treatment build up a resistive biofilm within the 24 h. Cells that remain in the supernatant predominantly appear as monomers or dimers. Treated B. subtilis cells have hampered biofilm formation and were not able to build up a confluent growing biofilm within the first 24 h. Moreover, the microscopic observation of PTW-treated suspension showed cellular aggregates with an unusually high connectivity of the individual cells. The findings suggest this cellular reaction as a counter measure against the adverse impact of PTW treatment. The experiments show the adverse impact of PTW on B. subtilis–biofilm formation and the phenomenological reaction of B. subtilis. Full article

Background: Antimicrobial resistance (AMR) has become precarious, warranting investments in antimicrobial discovery. Aim: To investigate the antibacterial activity of rosemary essential oil (REO), alone and in combination with selected conventional antibiotics. Methods: REO was subjected to antimicrobial susceptibility testing (including minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) determination) and investigation of anti-pre-biofilm and antibiofilm activities. Results: The phytochemical composition of the REO was eucalyptol (42.68%), bornanone (33.20%), endo-borneol (9.37%), α-terpeneol (7.95%), linalool (2.10%), bornyl acetate (1.81%), caryophyllene (1.09%), 4-terpeneol (0.94%), and anethole (0.87%). The antibacterial inhibition zones generally increased with increasing REO concentration (i.e., 10, 20, 50, 100, and 200 mg/mL). The MIC and MBC ranges of REO for all bacteria were 3.13–6.25 mg/mL and 3.12–12.5 mg/mL, respectively. The MICs (in µg/mL) of ciprofloxacin, chloramphenicol, streptomycin, tetracycline, and ampicillin, respectively, were Escherichia coli (0.98, 3.92, 1.96, 7.81, and 250), Klebsiella pneumoniae (1.25, 7.81, 125, 7.81, and 1000), MRSA (62.5, 7.81, 3.91, 7.81, and 250), Streptococcus mutans and Bacillus subtilis (125, 15.68, 250, 31.25, and 1000), Pseudomonas aeruginosa (125, 31.25, 500, 31.25, and 1000), and Salmonella Typhi (0.98, 15.68, 125, 1.96, and 1000). The MBC-MIC ratios of REO against all bacteria were in the range 1–2, indicating bactericidal effects. Mainly synergy (FICI = 0.16–0.37) was observed between REO and the conventional antibiotics. The IC50 values (in µg/mL) of REO against the bacteria, pre-biofilm vs. biofilm formation, were E. coli (1342.00 vs. 4.00), K. pneumoniae (106.00 vs. 3.00), MRSA (134.00 vs. 6.00), S. mutans (7259.00 vs. 7.00), B. subtilis (120.00 vs. 7.00), P. aeruginosa (4989.00 vs. 7.00), and S. Typhi (10.00 vs. 2.00). Conclusions: Rosemary essential oil had significant bactericidal effects on the bacteria tested, and its MIC and MBC values were low. Overall, it was synergistic with known conventional antibiotics and, thus, has encouraging prospects in combination therapy involving conventional antibiotics, even in the treatment of infections with multidrug-resistant bacteria, including biofilm-forming ones. Full article

In response to the escalating crisis of antimicrobial resistance (AMR), there is an urgent need to research and develop novel antibiotics. This study presents the synthesis and assessment of innovative 4-aminoquinoline-benzohydrazide-based molecular hybrids bearing aryl aldehydes (HD1-23) and substituted isatin warheads (HS1-12), characterized using multispectroscopic techniques with high purity confirmed by HRMS. The compounds were evaluated against a panel of clinically relevant antibacterial strains including the Gram-positive Enterococcus faecium, Bacillus subtilis, and Staphylococcus aureus and a Gram-negative Pseudomonas aeruginosa bacterial strain. Preliminary screenings revealed that several test compounds had significant antimicrobial effects, with HD6 standing out as a promising compound. Additionally, HD6 demonstrated impressively low minimum inhibitory concentrations (MICs) in the range of (8–128 μg/mL) against the strains B. subtilis, S. aureus and P. aeruginosa. Upon further confirmation, HD6 not only showed bactericidal properties with low minimum bactericidal concentrations (MBCs) such as (8 μg/mL against B. subtilis) but also displayed a synergistic effect when combined with the standard drug ciprofloxacin (CIP), highlighted by its FICI value of (0.375) against P. aeruginosa, while posing low toxicity risk. Remarkably, HD6 also inhibited a multidrug-resistant (MDR) bacterial strain, marking it as a critical addition to our antimicrobial arsenal. Computation studies were performed to investigate the possible mechanism of action of the most potent hybrid HD6 on biofilm-causing protein (PDB ID: 7C7U). The findings suggested that HD6 exhibits favorable binding free energy, which is supported by the MD simulation studies, presumably responsible for the bacterial growth inhibition. Overall, this study provides a suitable core for further synthetic alterations for their optimization as an antibacterial agent. Full article

The increasing antibiotic resistance among bacteria challenges the biotech industry to search for new antibacterial molecules. Endolysin TP84_28 is a thermostable, lytic enzyme, encoded by the bacteriophage (phage) TP-84, and it effectively digests host bacteria cell wall. Biofilms, together with antibiotic resistance, are major problems in clinical medicine and industry. The challenge is to keep antibacterial molecules at the site of desired action, as their diffusion leads to a loss of efficacy. The TP84_28 endolysin gene was cloned into an expression-fusion vector, forming a fusion gene cbd_tp84_28_his with a cellulose-binding domain from the cellulase enzyme. The Cellulose-Binding Thermostable TP84_Endolysin (CBD_TP84_28_His) fusion protein was biosynthesized in Escherichia coli and purified. Thermostability and enzymatic activities against various bacterial species were measured by a turbidity reduction assay, a spot assay, and biofilm removal. Cellulose-binding properties were confirmed via interactions with microcellulose and cellulose paper-based immunoblotting. The high affinity of the CBD allows for a high concentration of the fusion enzyme at desired target sites such as cellulose-based wound dressings, artificial heart valves and food packaging. CBD_TP84_28_His exhibits a lytic effect against thermophilic bacteria Geobacillus stearothemophilus, Thermus aquaticus, Bacillus stearothermophilus, and Geobacillus ICI and minor effects against mesophilic Bacillus cereus and Bacillus subtilis. CBD_TP84_28_His retains full activity after preincubation in the temperatures of 30–65 °C and exhibits significant activity up to its melting point at 73 °C. CBD_TP84_28_His effectively reduces biofilms. These findings suggest that integrating CBDs into thermostable endolysins could enable the development of targeted antibacterial recombinant proteins with diverse clinical and industrial applications. Full article

Background: The emergence and prevalence of antibiotic-resistant bacteria (ARBs) have become a serious global threat, as the morbidity and mortality associated with ARB infections are continuously rising. The activation of quorum sensing (QS) genes can promote biofilm formation, which contributes to the acquisition of drug resistance and increases virulence. Therefore, there is an urgent need to develop new antimicrobial agents to control ARB and prevent further development. Antimicrobial peptides (AMPs) are naturally occurring defense molecules in organisms known to suppress pathogens through a broad range of antimicrobial mechanisms. Methods: In this study, we utilized a previously developed deep-learning model to identify AMP candidates from the venom gland transcriptome of the spider Pardosa astrigera, followed by experimental validation. Results: PA-Win2 was among the top-scoring predicted peptides and was selected based on physiochemical features. Subsequent experimental validation demonstrated that PA-Win2 inhibits the growth of Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and multidrug-resistant P. aeruginosa (MRPA) strain CCARM 2095. The peptide exhibited strong bactericidal activity against P. aeruginosa, and MRPA CCARM 2095 through the depolarization of bacterial cytoplasmic membranes and alteration of gene expression associated with bacterial survival. In addition, PA-Win2 effectively inhibited biofilm formation and degraded pre-formed biofilms of P. aeruginosa. The gene expression study showed that the peptide treatment led to the downregulation of QS genes in the Las, Pqs, and Rhl systems. Conclusions: These findings suggest PA-Win2 as a promising drug candidate against ARB and demonstrate the potential of in silico methods in discovering functional peptides from biological data. Full article

Members of Bacillus species are able to enhance the level of available phosphorus (P) for plant absorption through mechanisms of P solubilization and mineralization. In our study, B. subtilis PE7 showed P-solubilizing activity in simple phosphate broth (SPB) medium, and acetic acid, iso-butyric acid, and iso-valeric acid were major organic acids responsible for the increase in soluble P and decrease in pH of SPB medium. In addition, strain PE7 released phytase on phytase-screening agar (PSA) medium, and analysis of semi-quantitative reverse transcription and polymerase chain reaction (sqRT-PCR) revealed that the phyC gene expression was the highest at 1 day after incubation. A low concentration of KH₂PO₄ in SPB medium induced more biofilm formation than a high concentration of KH₂PO₄. Strain PE7 showed swimming and swarming motilities in TY and TrA agar media. Under P starvation, inoculation with higher cell numbers of strain PE7 enhanced biomass and nutrient acquisition by melon plants, resulting in higher values of growth parameters and nutrient contents. Moreover, the persistence of bacterial cells on the root surface and in the rhizosphere of melon plants indicated colonization of the plants by strain PE7. Due to its capacity for P solubilization and mineralization, B. subtilis PE7 could be utilized as an alternative to synthetic fertilizer for P deficient-stress management in crop plantation. Full article

Biofilm obtained from Bacillus subtilis subsp. spizizenii inoculated on vegetable seeds has been shown to have plant growth-promoting capacity. Seed inoculation with biofilm produced by this strain could also reduce the adverse effects on plant growth caused by soil or substrate heavy metal overabundance. Therefore, the objective of this work was to evaluate the impact of biofilm inoculated on tomato (Solanum lycopersicum L.) seeds, which were planted on a substrate with artificially added zinc. First, seeds of the Río Grande tomato variety were exposed to increasing zinc concentrations, namely: 50, 100, 200, and 400 ppm, with and without bacterial biofilm inoculation. Zinc addition and seed inoculation affected germination parameters. For example, an extra 200 and 400 ppm of zinc led to high toxicity. Biofilm inoculation, however, reduced the noxious effects of excess zinc, bringing acute toxicity down to moderate. Then, tomato plants growing from inoculated and non-inoculated seeds were cropped for 4 months in both substrates with 400 ppm zinc and without added zinc. Extra zinc addition significantly (p < 0.05) reduced tomato root and shoot biomass, plant height, and fruit number at harvest time. However, seed biofilm inoculation avoided the harmful effect of zinc on plant growth parameters, fruit yield, and fruit quality. The roots and shoots of plants growing on contaminated substrates showed very noticeable increases in zinc levels compared to the control, while fruits only showed a much weaker zinc gain, even if this was significant (p < 0.05). Moreover, root shoot and fruit concentrations of elements other than zinc, (nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper, lead, and cadmium) were not or only weakly affected by the addition of this metal to the substrate. In summary, the biofilm of B. subtilis proved to be effective as a bioinoculant to alleviate negative effects on tomatoes cropped in a substrate with excess zinc. Full article

The current study investigates the biochemical composition and biological activities of ethanol extract from the fruit body of Tricholoma bufonium, marking the first detailed examination of this species. The primary goal was to assess the antimicrobial, anti-biofilm, and antioxidant properties of ethanol extract from the fruit body of T. bufonium against a range of bacterial strains. Conventional microbiological and biochemical techniques were employed to assess the antimicrobial efficacy of the extract and to determine its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Furthermore, a GC-MS analysis identified bioactive compounds, such as palmitic acid and oleic acid, which are likely contributors to the observed antimicrobial activity. The anti-biofilm activity was tested using glucose monohydrate-modified environments for biofilm formation, while the antioxidant potential was measured using the DPPH radical scavenging assay, CUPRAC (cupric ion reducing antioxidant capacity) assay, and FRAP (ferric ion reducing antioxidant power) assay. The ethanol extract exhibited potent antimicrobial activity, particularly against Enterococcus faecium, Bacillus subtilis, and Staphylococcus aureus MRSA, with MIC values as low as 0.0338 mg/mL for several pathogens. Additionally, the extract exhibited significant anti-biofilm activity against Bacillus cereus and antioxidant activity with an EC₅₀ value of 11.745 mg/mL. These results suggest that ethanol extract from the fruit body of T. bufonium may be a potent candidate for developing novel antimicrobial agents, particularly against resistant strains such as MRSA, while also providing antioxidant benefits. Full article

The enzyme-assisted approaches for plant phenolics extraction are more eco-friendly methods compared to acid or alkaline hydrolysis. Carbohydrase enzymes can release free phenolics from plant materials by cleaving the glycosidic bonds between phenolic compounds and cell wall polymers. In this study, the efficiency of carbohydrase-assisted treatment approaches was evaluated to extract bioactive phenolics from hawthorn (Crataegus orientalis) fruit residues. Enzymatic treatment of the fruits was operated by using a crude cellulolytic enzyme cocktail from Rhizomucor miehei NRRL 5282 and a pectinase preparate from Aspergillus niger. Both cellulase and combined cellulase–pectinase treatments improved the total phenolic content (TPC) and antioxidant activity of extracts. The TPC increased to 1899 ± 27 mg gallic acid equivalents/100 g dry matter during the combined enzyme treatment, showing a strong correlation with the average antioxidant capacity determined by ferric-reducing antioxidant power (1.7-fold increment) and 2,2-diphenyl-1-picrylhydrazyl (1.15-fold increment) reagents. The major phenolics in enzyme-treated extracts were vanillic and ferulic acids, the concentrations of which increased 115.6-fold and 93.9-fold, respectively, during carbohydrase treatment. The planktonic growth of Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Chromobacterium violaceum was slightly inhibited by the extracts with minimum inhibitory concentration values between 15.0 and 77.9 mg/mL, while the yeasts tested were quite resistant to the samples. B. subtilis and yeast biofilms were sensitive to the enzyme-treated extracts, which also showed quorum-sensing inhibitory effects against C. violaceum. The obtained bioactive hawthorn extracts hold potential as a natural source of antioxidants and antimicrobials. Full article