Inhibition Of Bacterial Growth Research Articles

Advancements in Composite Materials and Their Expanding Role in Biomedical Applications.

The synthesis of a Ni-doped ZnO nanocomposite incorporating chitosan (CS/Ni-doped ZnO) was achieved via a precipitation method, followed by annealing at 250 °C. This study comprehensively examined the nanocomposite's structural, functional, morphological, and porosity properties using various analytical techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high-resolution scanning electron microscopy (HR-SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis. The presence of chitosan (CS) and nickel (Ni) within the nanocomposite, along with their influence on reducing the band gap of ZnO particles and enhancing the generation of electron-hole pairs, was confirmed using UV-visible near-infrared spectroscopy (UV-vis-NIR). The electrochemical properties of the CS/Ni-doped ZnO nanocomposite were investigated via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) by utilizing a phosphate buffer solution with a pH of 6, which closely resembled the typical pH of bacterial cell walls. Finally, the prepared CS/Ni-doped ZnO nanocomposite was evaluated for its antibacterial and anticancer activities. The results demonstrated the highest inhibition of bacterial growth in P. vulgaris, whereas the lowest inhibition was found in S. aureus across various concentrations, thus highlighting its potential in antimicrobial applications. The cytotoxicity of CS/Ni-doped ZnO nanocomposites demonstrated remarkable effects with a half-maximum inhibitory concentration of approximately 80 ± 0.23 µg mL-1 against MCF-7 breast cancer cell lines, following a dose-dependent manner.

Antibacterial effect of periodic structure formed on SUS430 by using nanosecond pulsed laser

We investigated the laser-induced periodic surface structures (LIPSSs) formed on an SUS430 surface by irradiation with a nanosecond pulsed laser (Nd:YAG, wavelength of 532 nm, pulse width of 10 ns, number of pulses of 50, repetition rate of 10 Hz, and laser fluence of 1.2 J/cm2) and the antibacterial effect of the surface. LIPSSs with an interspacing of about 500 nm, which was close to the laser wavelength, were produced on the surface when the pulsed laser was near the ablation threshold. The film attachment method (JIS Z 2801) was used to measure the bacterial growth suppression on SUS430 surfaces with and without LIPSSs. On the surface without an LIPSS, the number of colonies was 1244, and on that with an LIPSS, the number was 198, indicating that the LIPSS formed by nanosecond pulsed laser irradiation inhibited the growth of bacteria. The chrome oxide layer on the SUS430 surface with the LIPSS may emit chrome ions from the edge of the LIPSS, enhancing the antibacterial effect.

Inhibition of host cell division by T5 protein 008 (Hdi).

Bacteriophages (phages) have evolved effective methods of exploiting host-cell machinery by redirecting molecular pathways. In this study, we describe an inhibitor of bacterial growth, T5.008, encoded by the T5 phage. High-throughput sequencing of genomic DNA from bacterial mutants resistant to T5.008 identified mutations in the Escherichia coli ftsZ gene, suggesting that T5.008 targets the cell division protein FtsZ. We validated this finding by replacing a residue in FtsZ with one that confers protection from T5.008 inhibition. We used time-lapse microscopy to show that T5.008 interferes with FtsZ ring formation and stability, thereby inhibiting division. We also demonstrated that phages expressing T5.008 can prevent host division before lysis much more efficiently than those lacking T5.008. We also showed that T5.008 provides a competitive advantage to the T5 phage. This strategy of inhibiting division during phage infection likely enables T5 phage to utilize host-cell resources efficiently.IMPORTANCEWe have identified a novel phage-encoded inhibitor of the major cytoskeletal protein in bacterial division, FtsZ. The inhibition is shown to confer T5 bacteriophage with a growth advantage in dividing hosts. Our studies demonstrate a strategy in bacteriophages to maximize their progeny number by inhibiting escape of one of the daughter cells of an infected bacterium. They further emphasize that FtsZ is a natural target for bacterial growth inhibition.

Alquremold Natural (AMN) for Growth Performance, Carcass Characteristics and Bacterial Growth Inhibition of Commercial Broilers

An experiment was conducted with 648-day-old Cobb 500 broiler chicks to evaluate the effects of Alquermold natural (AMN) on overall growth performance, carcass characteristics and inhibition of enteric bacterial growth of commercial broilers. The birds were randomly assigned to four different treatments: T0 (Control), T1 (0.5 g/kg AMN), T2 (1.0 g/kg AMN) and T3 (1.0 g/kg Mold Inhibitor (MI)), respectively. They were reared for up to 28 days. At the end of experiment, the birds’ growth performances in terms of body weight (BW), body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), survival, and meat production characteristics were recorded and calculated. Weekly fecal sample collection and microbiological count were performed to determine the bacterial load, specifically Escherichia coli and anaerobic bacteria in the broiler feces. The results showed that birds receiving 1.0 g/kg AMN had significantly higher BW and BWG (p0.01) than the control, 0.5 g/kg AMN, and MI groups. The FI and FCR of broilers were comparable in all treatment groups. There were no significant (p > 0.05) changes in meat yield parameters such as dressing percentage, neck, shank, drumstick, breast meat, thigh meat, and wing meat. However, when compared to the other dietary treatments, the bacterial load (E. coli and anaerobic bacteria) was significantly lower in the birds fed 1.0 g/kg AMN. Based on the findings, it can be concluded that feeding AMN at a rate of 1.0 g/kg may be considered for improving growth performance, maximizing feed utilization, and inhibiting bacterial load in the intestine of commercial broiler chickens.

Photocatalytic and antibacterial performance of β-cyclodextrin-TiO2 nanoparticles loading sorbic and benzoic acids

TiO2 nanoparticles (NPs) have been modified with β-cyclodextrin (βCD)-food preservative complexes. The susceptibility of Escherichia coli and Staphylococcus aureus to TiO2 NPs, sorbic acid (SA), benzoic acid (BA), and β-Cyclodextrin-TiO2 NPs including SA or BA, was studied. At 0.5 mg mL−1, TiO2 NPs were more effective in the inhibition of bacterial growth than modified-TiO2 NPs, achieving 71% inhibition rate. At the higher concentration of 3 mg mL−1 there were no significant differences between treatments, being all of them highly effective reaching 90% inhibition. Higher treatment-doses were related to slower growth rates. Flow cytometry findings suggested efficient NPs interaction with bacteria, being more noticeable in the case of TiO2 NPs. Regarding the photocatalytic activity, under 0.600 mW cm−2 irradiation, TiO2 NPs reached 95% methylene-blue dye degradation after 150 min, while βCD-TiO2 NPs showed 3-times lower kinetic constant. Overall results suggest potential application of the new systems in active packages to protect food from microbial spoilage.

Smart bactericide based on reduced graphene oxide decorated with copper and zinc nanoparticles

Graphene oxide (GO) synthesised by modified Tour’s method was decorated with copper and zinc nanoparticles (NPs) and simultaneously reduced by sodium borohydride to obtain a nanocomposite of reduced GO with copper and zinc NPs (rGO–Cu–Zn). The nanocomposite rGO–Cu–Zn was characterised by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The rGO–Cu–Zn was tested against Xanthomonas euvesicatoria (X. euvesicatoria), which attacks tomatoes and causes bacterial spots (BSs), and compared with the commercial product Champion 50 WG. Total bacterial growth inhibition was observed for the 1% rGO–Cu–Zn, whereas Champion 50 WG at the same concentration inhibited but did not eradicate all the bacterial colonies. To evaluate the negative effect of the rGO–Cu–Zn on the molecular level, the expression of the genes associated with the action of abiotic and biotic stress factors was analysed. Gene expression in the plants treated with 10% rGO–Cu–Zn did not exhibit a noticeable increase.Graphical

In Vitro Synergistic Inhibitory Effects of Plant Extract Combinations on Bacterial Growth of Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common pathogens of healthcare-associated infections. Medicinal plants have long been used in the traditional treatment of diseases or syndromes worldwide. Combined use of plant extracts could improve the effectiveness of pharmacological action by obtaining synergism, acting on multiple targets simultaneously, reducing the doses of individual components, and minimizing side effects. We aimed to investigate the synergistic inhibitory effects of selected medicinal plants (Caesalpinia sappan L. (CS), Glycyrrhiza uralensis Fisch. (GU), Sanguisorba officinalis L. (SO), and Uncaria gambir Roxb. (UG)) on the bacterial growth of MRSA and its clinical isolates. SO and UG extracts generated the best synergistic interaction as adjudged by checkerboard synergy assays. MICs of the individual extracts decreased 4-fold from 250 to 62.5 μg/mL, respectively. The SO + UG combination was further evaluated for its effects on bacterial growth inhibition, minimum bactericidal/inhibitory concentration (MBC/MIC) ratio, and time-kill kinetics. The results indicate that the SO + UG combination synergistically inhibited the bacterial growth of MRSA strains with bactericidal effects. SO + UG combination also exhibited more potent effects against clinical isolates. In multistep resistance selection experiments, both standard and isolates of MRSA showed no resistance to the SO + UG combination even after repeated exposure over fourteen passages. Our data suggest that using plant extract combinations could be a potential strategy to treat MRSA infections.

Environmental remediation promoted by silver nanoparticles biosynthesized by eucalyptus leaves extract

A simple and low-cost green synthesis method was optimized to prepare stable silver nanoparticles (AgNP) using aqueous Eucalyptus globulus leaves extract. This green method allows to obtain AgNP with spherical morphology and variable size around 25 nm, and it is dependent of the reaction temperature and concentration of the plant extract. AgNP stability was followed during 3 months by zeta potential measurements and a negative zeta range from −30.7 to −33.6 was determined. Biogenic-stabilized AgNP exhibited dual-functional properties as effective in environmental remediation with bacterial growth inhibition and dye photodegradation. Staphylococcus aureus and Escherichia coli were tested for antibacterial activity, and considerable inhibitory activity was found. High photocatalytic degradation of indigo carmine (IC) dye was performed in the presence of the AgNP as catalysts under sunlight irradiation. The degradation efficiency after 2 h of reaction was 37 %, 83 % and 98 % in the presence of UV light, visible light and sunlight irradiation, respectively. The germination of corn kernels test was used to determine the toxicity of the treated IC solutions and the results showed low toxicity after the photodegradation process.

Study the effect of the different doses from the laser on Staphylococcus aureus Bacteria growth in vitro

Background: Laser is a novel physical therapy technique used to treat various conditions, including wound healing, inhibition of bacterial growth, and postoperative wounds. High-power pulsed alexandrite laser therapy is one of the most prevalent forms of laser therapy, which is a noninvasive method for treating various pathological conditions, thereby enhancing functional capacities and quality of life. It is a modern medical and physiotherapeutic technology. Generally, the Alexandrite laser emits infrared light with a wavelength of 755 nm, allowing it to propagate and penetrate tissues. Objective: This study focused on the application of a high-power pulsed alexandrite laser in vitro to evaluate the effect of a pulsed alexandrite laser on antibiotic-resistant bacteria utilizing varying exposure times, pulse durations, and laser fluencies to determine which dose is more effective on S. aureus bacteria. Method: The laser used in this study was the alexandrite laser which was considered a pulsed laser and had the following parameters: The wavelength was 755 nm, the beam diameter was (14 mm), the exposure times varied (30, 60, 90) seconds, the laser fluency (5, 10, 15 and 20 J.Cm-2). The study was carried out after the bacteria were diagnosed as being antibioticresistant. They were exposed to different doses of Alexandrite laser. Three samples of bacteria were exposed to laser beams for 30 seconds with a 5ms pulse duration and with a laser fluency of 5J/cm2, and this process was repeated with laser fluencies of 10, 15, and 20. This procedure was repeated using exposure times of 60sec and 90sec. As well as, this process was repeated by exposure with 30 sec, 60 sec and 90 sec exposure times, 10ms and 20ms pulse durations and with different laser fluencies 5, 10, 15 and 20J/cm2, separately. Results: A significant reduction (p = <0.0001) in the mean values of the colony was observed with the increase of laser fluency doses compared with control at the same pulse duration. A significant reduction (p = <0.0001) in the mean count of the colonies was observed in the comparison between two laser fluences at the same pulse duration. In conclusion, the exposure times, pulse durations and laser fluencies of pulsed alexandrite laser showed an effect on the mean count of the colonies of S aureus bacteria and determined the effective dose. Keywords: laser, Staphylococcus aureus, Bacteria growth

Corrosion and bacterial growth inhibition by amino acid functionalized pyridine derivative at P110 steel/oil formation water interface: Experimental, surface and molecular docking investigations

The prime objective of the present research is to explore the green synthesis of pyridine derivative by functionalizing amino acid vanillin (Py-Va) using the ultrasound method and its application as a novel corrosion inhibitor for P110 steel in oil formation water (OFW). The results report that Py-Va inhibits P110 steel corrosion and represents a significant decrease in corrosion rate with the rising dose at certain temperatures. Electrochemical experiments manifest that Py-Va can restrain reactions of the cathode and anode of P110 steel. The molecular adsorption of Py-Va is governed by Langmuir isotherm with the chemical mechanism participation. The morphology maps of surface analysis support the creation of an inhibitive layer of Py-Va over the steel surface. Biological activity reveals a significant reduction in the sulfate-reducing bacteria (SRB) after Py-Va addition. Molecular docking and Root Mean Square deviation (RMSD) as used to analyze the Py-Va and SRB protein interaction.

Extrusion-blown oxidized starch/poly(butylene adipate-co-terephthalate) biodegradable active films with adequate material properties and antimicrobial activities for chilled pork preservation

Food safety concerns from spoilage and non-degradable packaging risk human health. Progress made in biodegradable plastic films, but limited study on biomass composite films with favorable morphological, mechanical, and inherent antibacterial properties for fresh meat preservation. Herein, we present a versatile packaging film created through the extrusion blowing process, combining oxidized starch (OST) with poly(butylene adipate-co-terephthalate) (PBAT). SEM analysis revealed even distribution of spherical OST particles on film's surface. FTIR spectra revealed new intermolecular hydrogen bonds between OST and PBAT. While combining OST slightly reduced tensile properties, all composite films met the required strength of 16.5 ± 1.39 MPa. Notably, films with 40 % OST showed over 98 % antibacterial rate against Staphylococcus aureus within 2 h. pH wasn't the main cause of bacterial growth inhibition; OST hindered growth by interfering with nutrient absorption and metabolism due to its carboxyl groups. Additionally, OST disrupted bacterial membrane integrity and cytoplasmic membrane potential. Remarkably, the OST/PBAT film excellently preserved chilled fresh pork, maintaining TVB-N level at 12.6 mg/100 g on day 6, microbial count at 105 CFU/g within 6–10 days, and sensory properties for 8 days. It extended pork's shelf life by two days compared to polyethylene film, suggesting an alternative to a synthetic material.

Food-protecting films based on soy protein isolate and natural deep eutectic solvents: Antimicrobial and antioxidant properties

Natural deep eutectic solvents (NADES) have just recently emerged as promising plasticizers in food coating applications owing to their excellent anti-frosting properties, low cost, and biosafety. Herein, we report for the first time the use of NADES as bioactive additives of soy protein isolate (SPI) to fabricate functional packaging materials. A neoteric eutectic solvent based on choline chloride/tannic acid (ChCl/TA) and the classical ChCl/citric acid mixture (ChCl/Cit) were explored to be integrated into the protein matrix at really high ratios (150 and 200 wt%). The resulting films were characterized by assessing morphological, physicochemical, and mechanical properties, as well as antioxidant and antimicrobial activities. The films exhibited a hydrophilic surface but limited water swelling (less than 10%), suggesting the formation of a crosslinked network between NADES and SPI. The ChCl/Cit films demonstrated potent antimicrobial activity in bacterial growth inhibition assay on chicken breast as well as in agar diffusion assays with inhibition zone diameters over 20 mm for gram+ and gram-bacteria, while ChCl/TA films showed the highest tensile strength (ranging from 744 to 2740 kPa), superior antioxidant activity (DPPH scavenging activity of ≈82%), and high light barrier properties, advantageous for storing light-sensitive food products. The incorporation of high concentrations of NADES in film production provides a novel and practical approach to improving the properties of protein materials for food packaging applications.

Gliotoxin-mediated bacterial growth inhibition is caused by specific metal ion depletion

Overcoming antimicrobial resistance represents a formidable challenge and investigating bacterial growth inhibition by fungal metabolites may yield new strategies. Although the fungal non-ribosomal peptide gliotoxin (GT) is known to exhibit antibacterial activity, the mechanism(s) of action are unknown, although reduced gliotoxin (dithiol gliotoxin; DTG) is a zinc chelator. Furthermore, it has been demonstrated that GT synergises with vancomycin to inhibit growth of Staphylococcus aureus. Here we demonstrate, without precedent, that GT-mediated growth inhibition of both Gram positive and negative bacterial species is reversed by Zn2+ or Cu2+ addition. Both GT, and the known zinc chelator TPEN, mediate growth inhibition of Enterococcus faecalis which is reversed by zinc addition. Moreover, zinc also reverses the synergistic growth inhibition of E. faecalis observed in the presence of both GT and vancomycin (4 µg/ml). As well as zinc chelation, DTG also appears to chelate Cu2+, but not Mn2+ using a 4-(2-pyridylazo)resorcinol assay system and Zn2+ as a positive control. DTG also specifically reacts in Fe3+-containing Siderotec™ assays, most likely by Fe3+ chelation from test reagents. GSH or DTT show no activity in these assays. Confirmatory high resolution mass spectrometry, in negative ion mode, confirmed, for the first time, the presence of both Cu[DTG] and Fe[DTG]2 chelates. Label free quantitative proteomic analysis further revealed major intracellular proteomic remodelling within E. faecalis in response to GT exposure for 30–180 min. Globally, 4.2–7.2% of detectable proteins exhibited evidence of either unique presence/increased abundance or unique absence/decreased abundance (n = 994–1160 total proteins detected), which is the first demonstration that GT affects the bacterial proteome in general, and E. faecalis, specifically. Unique detection of components of the AdcABC and AdcA-II zinc uptake systems was observed, along with apparent ribosomal reprofiling to zinc-free paralogs in the presence of GT. Overall, we hypothesise that GT-mediated bacterial growth inhibition appears to involve intracellular zinc depletion or reduced bioavailability, and based on in vitro chelate formation, may also involve dysregulation of Cu2+ homeostasis.

Binding-induced thermal stabilization of mosR and ndhA G-quadruplex comprising genes by emodin leads to downregulation and growth inhibition in Mtb: Potential as anti-tuberculosis drug

Non-canonical G-quadruplex (G4) DNAs in genome of living organisms are involved inregulation of several cellular activities. Understanding of G-quadruplex interaction with anthraquinones is significant, in the continuing search for an effective therapeutic target against tuberculosis disease causing Mycobacterium tuberculosis virulent strains. Emodin interacts with G4 DNA forming genes, mosR and ndhA, that are essential in ATP synthesis and hypoxic growth of bacterial strains inside host cell. The observed hypochromism, red shift ∼ 6–11 nm, fluorescence quenching, shortening of fluorescence lifetime and appearance of negative induced circular dichroism band during interaction suggest binding of emodin to grooves/loops and end stacking with guanine quartets. The thermodynamically favorable reaction, involving non-intercalative binding mechanism in two distinct modes, is enthalpy driven with affinity constant ∼ 6 × 104 M−1. Inhibition of bacterial growth, Taq polymerase enzyme and significant downregulation of mosR and ndhA genes (2–4 orders) by emodin may be attributed to binding-induced thermal stabilization, ΔTm ∼ 23 and 14 °C in ndhA and mosR G4 DNA complexes, respectively. The studies demonstrate G4 DNA as promising pharmacological targets for developing effective anti-tuberculosis treatments and therapeutic potential of emodin in targeting pathogen persistence genes, particularly in view of emerging multi drug resistant deadly strains.

Synthesis, cytotoxicity, and antibacterial studies of 2,4,5,6-substituted hexahydro-1H-isoindole-1,3(2H)-dione.

In this study, synthesis of novel isoindole-1,3-dione analogues bearig halo, hydroxy, and acetoxy groups at the position 4,5,6 of the bicyclic imide ring was performed to examine their potential anticancer effects against some cell lines. A multistep chemical pathway was used to synthesize the derivatives. The cytotoxic effect of trisubstituted isoindole derivatives were evaluated by determining cellular viability using the MTT assay against A549, PC-3, HeLa, Caco-2, and MCF-7 cell lines. The C-2 selective ring-opening products were obtained from the ring-opening reaction of 5-alkyl/aryl-2-hydroxyhexahydro-4H-oxireno[2,3-e]isoindole-4,6(5H)-diones with nucleophiles such as chloride (Cl- ) and bromide (Br- ) ions. In addition, the ring-opening products halodiols were converted to their related acetates. The anticancer activity of synthesized isoindole-1,3-dione derivatives was investigated against HeLa, A549, MCF-7, PC3, and Caco-2 cells in vitro and resulted in varies cytotoxic effect depend on the group attached to the isoindole molecule. Furthermore, the evaluation of the antimicrobial action of trisubstituted isoindole derivatives against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria was assessed and found out selective inhibition of the both bacterial growth via different trisubstituted isoindole derivatives. The results of this work encourage further research on the potential utilization of trisubstituted isoindole derivatives as cytotoxic and antimicrobial agents.

An In Vitro Evaluation of the Antibacterial Efficacy of Solanum xanthocarpum Extracts on Bacteria From Dental Plaque Biofilm.

The focus of research has recently shifted toward developing herbal-based medicines due to the emerging bacterial resistance and side effects of antibiotics. Solanum xanthocarpum (Sx) is a medicinal plant with potent pharmacological properties. This study aimed to evaluate the antibacterial activity of its crude extracts on bacteria isolated from dental plaque in patients with gingivitis. Aqueous, ethyl acetate, hexane, chloroform, and ethanolic extracts were prepared from Sx. Dental plaque samples were collected from patients with plaque-induced gingivitis. Disk diffusion assay was performed to determine the antibacterial activity of the extracts at concentrations of 25 mg/ml, 50 mg/ml, and 75 mg/ml with ampicillin 200 mg/ml as a positive control. The minimum inhibitory concentration (MIC) of the aqueous extract was also evaluated by broth dilution test against bacteria isolated from dental plaque biofilm. The antibacterial activity was estimated by measuring the zones of inhibition through the disc diffusion method. The Kruskal Wallis with Dunn post hoc test performed for intergroup comparison between the various extracts showed a statistically significant difference in inhibition of bacterial growth between 25 mg/ml and 75 mg/ml concentrations. There was no significant difference between the 75 mg/ml Sx concentration and the positive control. In addition, the MIC was elucidated to be 0.625 g/ml, at which there was maximum inhibition of bacterial growth. The Sx extract exhibited antibacterial activity against periodontal pathogens. Thus, it can be concluded that optimum concentrations of Sx could be used in therapeutic strategies to prevent and manage periodontal diseases.

Thin layer chromatography-direct bioautography for investigation of antibacterial activities of Artemisia sieversiana Ehrhart ex Willd. essential oil

The aim of the study was to characterise the chemical composition of the essential oil extracted from a Chinese traditional aromatic herb, Artemisia sieversiana Ehrhart ex Willd and investigate its antimicrobial activities against Staphylococcus aureus, the test bacterium, using thin-layer chromatography-direct bioautography (TLC-DB). Gas chromatography-mass spectrometry analysis showed that the essential oil was dominated by chamazulene (44.44%). Undeveloped TLC-DB enabled the measurement of zone of inhibition as valid as and more sensitive than the traditional agar diffusion method. The overall antimicrobial effect was weak at the tested concentration range and the antimicrobial strength did not exhibit concentration dependence. At high essential oil concentration (>1000μg/ml), size of zone of inhibition was all <7mm. Developed TLC-DB separated the components and visualised the inhibition of bacterial growth on the plate surface where the active antimicrobials were determined to be the minor components, hydroxylated terpenes, rather than the dominant component, chamazulene.

Antioxidant, Anti-Tyrosinase, and Anti-Skin Pathogenic Bacterial Activities and Phytochemical Compositions of Corn Silk Extracts, and Stability of Corn Silk Facial Cream Product.

Zea mays L. Poaceae stigma (corn silk, CS) is a byproduct of agricultural waste and is used as a traditional herb in many countries. CS is rich in chemical compounds known to benefit human health and is also a remedy for infectious diseases and has anti-proliferative effects on human cancer cell lines. In the present study, CS extract has been evaluated for its antioxidant, antibacterial, and anti-tyrosinase activities and its phytochemical composition. The higher total phenolic and flavonoid contents were found in the ethanolic extract of corn silk (CSA), at 28.27 ± 0.86 mg gallic acid equivalent/g extract and 4.71 ± 0.79 mg quercetin equivalent/g extract, respectively. Moreover, the antioxidant content of CSA was found at 5.22 ± 0.87 and 13.20 ± 0.42 mg gallic acid equivalent/g extract using DPPH and reducing power assays. Furthermore, the ethanolic extract of corn silk showed tyrosinase inhibition with an IC50 value of 12.45 µg/mL. The bacterial growth inhibition of CSA was tested using agar disc diffusion and broth dilution assays against Cutibacterium acnes and Staphylococcus epidermidis. It was found that CSA inhibited C. acnes and S. epidermidis with an inhibition zone of 11.7 ± 1.2 and 9.3 ± 0.6 mm, respectively. Moreover, the CSA showed MIC/MBC of 15.625 mg/mL against C. acnes. The following phytochemical compounds were detected in CSA: cardiac glycosides; n-hexadecanoic acid; hexadecanoic acid, ethyl ester; oleic acid; and 9,12-octadecadienoic acid, ethyl ester. After the corn silk cream product was formulated, the product demonstrated stability without phase separation. This research is beneficial for promoting effective ways to use agricultural waste while utilizing the antioxidant, anti-tyrosinase, and antibacterial activities of corn silk. Moreover, the use of technology and innovation to obtain high-value CS extract will benefit the development of commercial cosmetic products by providing safe, natural, and quality ingredients to the consumer.

Isolation and Identification of Endophytic Bacteria Bacillus sp. ME9 That Exhibits Biocontrol Activity against Xanthomonas phaseoli pv. manihotis.

In recent years, the bacterial blight of cassava has caused substantial economic losses to the Chinese cassava industry. Chemical control methods have become the primary approach to control this disease; however, their widespread usage and harmful residues have raised concerns about environmental pollution. In order to avoid this, it is urgent to seek a green ecological method to prevent and control it. Biological control through the utilization of microorganisms not only effectively inhibits the disease, but also gives consideration to environmental friendliness. Therefore, investigating an endophytic biological control method for cassava bacterial blight is of great importance. In this study, cassava leaf tissues were used as test specimens in order to isolate endophytic bacteria by using dilution and separation methods. Bacillus ME9, derived from cassava endophytic bacteria, exhibits good antagonism against a diverse range of pathogens, including Xpm11. Its genome consists of a series of genes encoding antibacterial lipopeptides, which may be directly related to its antibacterial capabilities. Furthermore, inoculation resulted in a substantial change in the diversity of the endophytic bacterial community, characterized by improved diversity, and displayed an obvious inhibition of pathogenic bacterial growth, demonstrating successful colonization within plants. The results laid a foundation and provided theoretical support for the development and utilization of cassava endophytic bacterial diversity and endogenous disease control strategies.

Egg Yolk as a New Source of Peptides with Antioxidant and Antimicrobial Properties.

A significant increase in interest in food-derived peptides obtained mostly through enzymatic reactions has been observed in the past few years. One of the best sources of bioactive peptides are defatted egg yolk proteins, which can potentially find application as high-quality nutritional supplements for infants with cow's milk protein intolerance and as natural preservatives. The aim of this study was to obtain peptides from defatted egg yolk protein, to study their antioxidant and antimicrobial properties, and to identify peptides with bioactive properties To control the course of the process, MALDI-TOF/MS (matrix-assisted laser desorption/ionization time-of flight/mass spectrometry) spectra were also examined. The peptide mixture obtained through enzyme digestion was tested for its antioxidant properties by measuring the scavenging activity in 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization (ABTS•+), and ferric reducing activity (FRAP) assays. Antimicrobial activity was also studied. The peptide mixture exhibited significant antioxidant activity: DPPH-1776.66 ± 32.99, ABTS-390.43 ± 8.92, and FRAP-16.45 ± 0.19. The inhibition of bacterial growth by two concentrations of the peptide mixture was examined. The best result was obtained in Bacillus cereus, with an inhibition zone of 20.0 ± 1.0 and 10.7 ± 0.6 mm at the concentrations of 50 and 25 mg/mL, respectively. The results of the study suggest that the mixture of egg yolk peptides may exhibit a number of health-promoting properties.