Good Activity Research Articles

Acute toxicity and anti-inflammatory activity of an improved traditional medicine developed in Burkina Faso

An Improved Traditional Medicine (ITM) in capsule form presented by traditional health practitioners in Burkina Faso as used for hepatoprotective and hepatocurative treatment for viral hepatitis B. The study's main objective was to investigate the anti-inflammatory properties of this ITM, which is used in treating viral hepatitis B in traditional medicine in Burkina Faso. Phytochemical screening revealed the presence of flavonoids, saponins, tannins, coumarins, alkaloids, sterols and triterpenes. The in vitro anti-inflammatory assay inhibited LOX by 15.69 ± 0.50% at a 100 µg/mL concentration. The LD50 was estimated to be greater than 5000 mg/kg. In vivo activity using the carrageenan anti-oedema test showed good dose-dependent anti-inflammatory activity of ITM at 30, 65 and 130 mg/kg bw. After 3 hours, the extract at various doses reduced edema to over 50% inhibition. After 5 h, oedema was reduced to 85.209% at the 130 mg/kg. However, the reference acetylsalicylic acid (ASA) at 100 mg/kg bw showed a percentage of 85.048% at 5 h. The IC50 obtained after the ABTS, FRAP and LPO antioxidant tests of the phytomedicine were 351.00 µg/mL, 353.20 mM EAA/L and 81.13%. However, the IC50 with the DPPH method was higher than 104 mg/mL. The phytomedicine would have anti-inflammatory and antioxidant properties due to the presence of bioactive phytochemicals on inflammation and free radicals. Keywords: ITM, Phytochemical, Acute toxicity, Anti-inflammatory, Antioxidants

Effect of Hydroxyapatite Nanowires on Formation and Bioactivity of Osteoblastic Cell Spheroid.

Compared with traditional high-density cell spheroids, which are more prone to core necrosis, nanowires effectively improve the biological activity of core cells in spheroids, emanating more innovations for optimizing the internal cell survival environment and providing differentiation signals. In this study, hydroxyapatite nanowires (HAW), which provide numerous material exchange channels for internal cells by interpenetrating into cell spheroids, were added to osteoblast precursor (MC3T3-E1) cell spheroids. HAW, synthesized using the hydrothermal method, was used as a regulatory material to prepare uniformly sized 3D composite spheroids with good biological activity. Subsequently, material characterization and biocompatibility tests were performed on HAW, and the biological activity and osteogenic differentiation ability of the cell spheroids were tested. Notably, in 2D coculture, HAW displayed a certain attraction to MC3T3-E1 cells and promoted cell aggregation toward it. The content of HAW determined whether composite cell spheroids can form aggregated spherical structures, and incorporation of HAW alleviated core necrosis and enhanced the osteogenic phenotype. In summary, these findings indicate that the prepared HAW-bone cell composite spheroids can potentially be used as building blocks for the construction of large high-density biomimetic tissues and organoids using 3D bioprinting technology.

Octenylsuccinated alginate as a delivery agent for encapsulation of bergamot essential oil: Preparation, functional properties and release behavior

This study evaluate the effect of succinylation of sodium alginate (ALG) by octenyl succinic anhydride (OSA) and its effect on the bergamot essential oil (BEO)-loaded ALG beads. The physico-chemical, antioxidant, antibacterial, and in vitro release properties of BEO-loaded ALG beads were assessed. The presence of BEO in alginate beads was assessd using Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and differential scanning calorimetry (DSC) experiments. The higher amount of BEO in modified alginate beads at higher degree of substitution (DS) has been confirmed. Accordingly, it was discovered that the DS has notable effects on encapsulation efficiency (EE), loading capacity (LC) of beads, so that the values of EE and LC were about 31–75 % and 19–45 %, respectively, when the DS value of ALG was 0.00–0.022. Besides, BEO-loaded beads prepared using high DS, exhibited higher total phenolic compound (TPC = 21.101 mg garlic acid/g brad), good antioxidant activity (DPPH radical scavenging activity ≈ 69 %) and antibacterial properties (against E. coli and S. aureus). In vitro release analysis showed the initial fast release followed by a slow-release. OSA modification slowed down the release rate of bergamot essential oil from alginate beads. Also, the release of BEO from the beads followed Fickian diffusion.

Polyphenols with anti-inflammatory activity isolated from the whole herbs of Delphinium forrestii var. Viride

Delphinium belongs to Ranunculaceae, which is widely distributed in Northwest China. In folk, this genus of plants has analgesic, anti-inflammatory, and insecticidal effects. By studying non-alkaloid components in the whole herbs of Delphinium forrestii, we obtained a total of 11 compounds (1−11), including five new (1–5) and six known polyphenols (6–11). On the basis of chemical evidences and spectral data analysis (UV, Optical rotation data, 1D/2D-NMR and HR-ESI-MS), the structures of new compounds were elucidated. The inhibitory effect of compounds 1–11 on lipopolysaccharide (LPS) induced NO production in RAW 264.7 cells was detected. Compounds 4 and 11 showed significant inhibitory effects. This study indicated the presence of compounds with good anti-inflammatory activity among non-alkaloid components in the whole herbs of Delphinium forrestii.

Synthesis and biological evaluation of 1, 2, 3-triazole incorporated pyrrole derivatives as anticancer agents

A new series of 1,2,3-triazole skeleton incorporated pyrrole derivatives (11a–j) were developed and their chemical structures were confirmed by analytical data. Further, the anticancer profile of these newly derived compounds 11a–j was assessed against four types of human cancer cell lines such as human breast cancer (MCF-7), lung cancer (A549), colon cancer (Colo-205) and ovarian cancer (A2780) by employing of the MTT method and was compared with etoposide used as a positive control. Most of the examined derivatives displayed moderate to good activity compared with the positive control. Among them, five compounds 11a, 11b, 11c, 11d, and 11e showed more potent activity. Particularly, compound 11a showed superior activity.

Continuous processing of JP-10 production: Hydroisomerization of endo-tetrahydrodicyclopentadiene to exo-tetrahydrodicyclopentadiene using a novel bimetal catalyst of Ba/Se supported on TiO2/SO4

High-energy-density liquid fuels can be utilized as an energetic supplement to conventional fuels and are essential for volume-limited aerospace vehicles to boost payload and flying range. JP-10 has attracted much attention because of its high density, flash point, high volumetric heat, and low freezing point. Here we report the hydroisomerization of endo-tetrahydrodicyclopentadiene to exo-tetrahydrodicyclopentadiene (the main component of JP-10) was investigated over the TiO2/SO4 supported Ba(10 %)/Se(5–20 %) catalysts. This work aims to examine changes in continuous processing settings to maximize exo-THDCPD production, selectivity, and conversion. It was discovered that the synthesized TiO2/SO4/Ba(10 %)/Se(5–20 %) heterogeneous catalysts were novel, more effective, affordable, environmentally friendly, and simple to produce. The catalyst’s physicochemical characteristics were examined using FT-IR, BET, XRD, HR-SEM, HR-TEM, TGA and NH3-TPD. The produced TiO2/SO4/Ba(10 %)/Se(5–20 %) nano-catalysts have good catalytic activity and a wide range of active Lewis and Brønsted acid sites. Evaluation of the isomerization of endo-THDCPD to exo-THDCPD was conducted in a high-pressure fixed-bed continuous reactor operating at 200 °C, 20 bar of pressure, and 4.0mol/h of H2 flow rate. According to the investigations, the synthesized catalyst with a 15 % Se load performs exceptionally well, exhibiting 100 % conversion, 98.5 % selectivity, and 98.5 % yield at an H2 flow rate of 10 ml/min. The isomerized product is used in Jet Propellant-10, a high-density fuel. Under ideal circumstances, exo-THDCPD with a high degree of purity (>98 wt%) was produced without the need for any sort of separation technique.

Development of Novel Biocomposites with Antimicrobial-Activity-Based Magnesium-Doped Hydroxyapatite with Amoxicillin.

Background/Objectives: A biocomposite based on magnesium-doped hydroxyapatite and enriched with amoxicillin (MgHApOx) was synthesized using the coprecipitation method and is presented here for the first time. Methods: The stability of MgHAp and MgHApOx suspensions was evaluated by ultrasound measurements. The structure of the synthesized MgHAp and MgHApOx was examined with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The crystalline structure was determined by X-ray diffraction. The FTIR data were collected in the range of 4000-400 cm-1. The morphology of the nanoparticles was evaluated by scanning electron microscopy (SEM). Furthermore, the biocompatible properties of MgHAp, MgHApOx and amoxicillin (Ox) suspensions were assessed using human fetal osteoblastic cells (hFOB 1.19 cell line). The antimicrobial properties of the MgHAp, MgHApOx and Ox suspension nanoparticles were assessed using the standard reference microbial strains Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. Results: X-ray studies have shown that the biocomposite retains the characteristics of HAp and amoxicillin. The SEM assessment exhibited that the apatite contains particles at nanometric scale with acicular flakes morphology. The XRD and SEM results exhibited crystalline nanoparticles. The average crystallite size calculated from XRD analysis increased from 15.31 nm for MgHAp to 17.79 nm in the case of the MgHApOx sample. The energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analysis highlighted the presence of the constituent elements of MgHAp and amoxicillin. Moreover, XPS confirmed the substitution of Ca2+ ions with Mg2+ and the presence of amoxicillin constituents in the MgHAp lattice. The results of the in vitro antimicrobial assay demonstrated that MgHAp, MgHApOx and Ox suspensions exhibited good antimicrobial activity against the tested microbial strains. The results showed that the antimicrobial activity of the samples was influenced by the presence of the antibiotic and also by the incubation time. Conclusions: The findings from the biological assays indicate that MgHAp and MgHApOx are promising candidates for the development of new biocompatible and antimicrobial agents for biomedical applications.

Mo-doped carbon-dots nanozyme with peroxide-like activity for sensitive and selective smartphone-assisted colorimetric S2− ion detection and antibacterial application

Sulfur ion (S2−) plays a significant and considerable role in many living organisms and ecosystems, while its abnormal content can pose a serious hazard to human health and ecological environment. Hence, it is extremely meaningful to construct a highly sensitive and selective analytical platform for S2− detection in complex microenvironment, particularly in biological systems. In this study, phosphomolybdic acid and L-Arg were utilized to prepare a new molybdenum doped carbon-dots nanozyme (Mo-CDs) with great peroxidase-like activity by one-step hydrothermal approach. In the presence of H2O2, Mo-CDs converted 3,3′,5,5′-tetramethyl benzidine (TMB) into blue oxTMB, but S2− strongly reduced the blue solution to colorless and then brown, which established significant selectivity toward S2−. Mo-CDs illustrated a wide linear range (2.5 μM–900 μM) and low detection limit (LOD = 76 nM) by ultraviolet and smartphone-assisted visualized colorimetric analysis. Especially, the smartphone-assisted analysis platform successfully realized quick, portable, sensitive and visible identification of S2− with high recovery (95.7–106.7 %) and excellent specificity in water samples. More importantly, Mo-CDs was developed to antibacterial applications based on good peroxidase-like activity. This research not only constructed a new and efficient carbon-dots nanozyme and a low-cost, portable, visual analysis platform for real-time detection of S2−, but also proposed a novel design strategy and methodology for exploiting multifunctional nanozyme detection tool with great practical application.

Silver Nanoparticles and Simvastatin-Loaded PLGA-Coated Hydroxyapatite/Calcium Carbonate Scaffolds.

The need to develop synthetic bone substitutes with structures, properties, and functions similar to bone and capable of preventing microbial infections is still an ongoing challenge. This research is focused on the preparation and characterization of three-dimensional porous scaffolds based on hydroxyapatite (HA)-functionalized calcium carbonate loaded with silver nanoparticles and simvastatin (SIMV). The scaffolds were prepared using the foam replica method, with a polyurethane (PU) sponge as a template, followed by successive polymer removal and sintering. The scaffolds were then coated with poly(lactic-co-glycolic) acid (PLGA) to improve mechanical properties and structural integrity, and loaded with silver nanoparticles and SIMV. The scaffolds were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), ATR FT-IR, and silver and SIMV loading. Moreover, the samples were analyzed by Brillouin and Raman microscopy. Finally, in vitro bioactivity, SIMV and silver release, and antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis were evaluated. From the Brillouin spectra, samples showed characteristics analogous to those of bone tissue. They exhibited new hydroxyapatite growth, as evidenced by SEM, and good antimicrobial activity against the tested bacteria. In conclusion, the obtained results demonstrate the potential of the scaffolds for application in bone repair.

Isolation, characterization, and application of a novel Pseudomonas fluorescens phage vB_PF_Y1-MI in contaminated milk.

The food industry has incurred substantial losses from contamination by Pseudomonas fluorescens, emphasizing the critical importance of implementing effective control strategies. Phages are potential sterilizers due to their specific killing abilities and the difficulty bacteria face in developing resistance. However, a significant barrier to their development is the lack of diversity among phage types. In this study, we characterized a novel lytic P. fluorescens phage, named vB_PF_Y1-MI. Phage vB_PF_Y1-MI displayed a latent period of nearly 10min and a high burst size of 1493 PFU/cell. This phage showed good activity over a wide range of temperature (up to 70°C) and pH (3-12). The genome of phage vB_PF_Y1-MI spans 93,233bp with a GC content of 45%. It encompasses 174 open-reading frames and 19 tRNA genes, while no lysogeny or virulence-associated genes were detected. Phylogenetic analysis positions it as a novel unassigned evolutionary lineage within the Caudoviricetes class among related dsDNA phages. Our study provides foundational insights into vB_PF_Y1-MI and emphasizes its potential as an effective biological control agent against P. fluorescens. This research offers crucial theoretical groundwork and technical support for subsequent efforts in preventing and controlling P. fluorescens contamination.

Molecular Docking Studies of Tribulus Terrestris Phytochemicals Against Bovine Mastitis Caused by Methicillin-resistant Staphylococcus Aureus

Bovine mastitis caused by methicillin-resistant Staphylococcus aureus is among the diseases capable of transferring from animal to human. It often leads to the development of antibiotic-resistant genes in both humans and animals. It is marked by the failure of the active-serine site of the blaZ gene in association with mecA to hydrolyze antibiotics which will inhibit the production of the beta-lactamase enzyme. This research aims to assess the interactions and binding affinities of Tribulus terrestris phytochemicals and important bacterial proteins involved in bovine mastitis. The research process begins with the identification of important bacterial proteins responsible for bovine mastitis and then the preparation of protein and ligand structures. Consequently, docking was performed, and interactions between protein-ligand were analyzed and visualized. Four phytoconstituents of Tribulus Terrestris (2,7-Diphenyl-1,6-dioxopyridazino [4,5:2',3'] pyrrolo [4',5'] pyridazine, gitogenin, tigogenin, and hecogenin) were chosen, and molecular docking simulations revealed all the four compounds exhibit good binding affinities. The docking scores of the ligands with blaZ are as follows; 2,7-Diphenyl-1,6-dioxopyridazino [4,5:2',3'] pyrrolo [4',5'] pyridazine (-7.9), gitogenin (-8.9), tigogenin (-8.9) and hecogenin (-9.0). Also, the docking scores of the ligands with mecA are as follows; 2,7-Diphenyl-1,6-dioxopyridazino [4,5:2',3'] pyrrolo [4',5'] pyridazine (-9.4), gitogenin (-6.4), tigogenin (-6.5) and hecogenin (-6.8). Based on the predicted ADMET values using the Lipinski and Veber rule, compounds with potentially good activities were identified. The results suggest that only tigogenin is likely to exhibit antibacterial activity by binding with the active-serine site of blaZ

Preparation of novel nanoparticle demulsifier and its demulsification for surfactant-stabilized crude oil emulison

The application of nanoparticle (NP) demulsifiers in processing the emulsified crude oil production fluid is of great significance for improving production efficiency and reducing energy consumption in crude oil extraction. In this work, a novel NP demulsifier (PPA@KAO) was prepared by chemically modifying the mineral kaolinite (KAO) nanoparticles using γ-Methacryloyl propyltrimethoxysilane (MPS) and polyether-polyquaternium (PPA). The morphology and structure of the PPA@KAO demulsifiers were characterized by FT-IR, SEM, TG, XPS and Zeta potential. The contact angle measurements, interfacial tension (IFT) characterization, and the distribution of nanoparticles in the oil-water phase showed that PPA@KAO have good amphiphilicity and interfacial activity. The demulsification performance of PPA@KAO demulsifiers for a sodium dodecyl benzene sulfonate (SDBS) stabilized crude oil emulsion was studied with bottle method. It was found that the oil-water separation could be completed within 20 min, with a demulsification efficiency of 96.75 % at a dosage of 3 g L−1，pH of 6 and temperature of 30°C. Such a result indicates that the PPA@KAO NP demulsifier can achieve rapid and efficient demulsification for the surfactant-stabilized crude oil emulsion at room temperature. The demulsification mechanism of PPA@KAO for the SDBS-stabilized crude oil emulsion was well revealed, which provides an important synthetic strategy of how obtaining an effective NP demulsifiers by regulating the amphiphilicity and surface functional groups of the nanoparticles.

Synthesis and design strategies of codoped titanium dioxide with band alignment and multiple reflections of incident light for efficient visible light activity

To increase the visible-light photocatalytic performance of Titania, it was codoped with specific elements and was effectively synthesized. The goal of enhancing visible-light photocatalytic performance was achieved by broadening its absorption spectrum in the visible light range and enhancing the quantum efficiency of the photocatalytic reaction toward the degradation of the hazardous dye methyl orange. Mixed phase photocatalyst with different percentage hierarchical secondary nanostructure has been synthesized by the combination of chemical bath deposition methods and hydrothermal. The density of the sprout-like branches changes from the concentration levels of titanium butoxide in the precursor solution. Based on the experimental analysis, a mechanism was proposed to interpret the evolution of the secondary growth. The band edge difference between anatase and TiO2(B) phases induces transfer of charge at the interface. The result revealed that in the TiO2 crystal some O-sites were substituted by N and S anions resulting in band mixing and incorporation of extra energy states in between the valence band maxima and conduction band minimum, which caused a shift towards longer wavelengths in the absorption edge. Compared with pure TiO2 nanobelt, the surface modified doped samples exhibited good visible light activity. The combined effect of fast charge transfer in the atomic level contact between two phases and localized N 2p and S 3p band above valence-band edge in the same material makes titanium dioxide suitable for use in the presence of visible light.

Low-Foaming Nonionic Gemini Surfactants Containing Hydrophilic Poly(oxyethylene) Chain and Hydrophobic Di-tert-pentylbenzenes Groups.

Low-foaming nonionic gemini surfactants have a wide range of applications in industrial cleaning and photoresist development. In this study, three low-foaming nonionic gemini surfactants (S1, S2, and S3) with different poly(oxyethylene) chain lengths have been synthesized by using methoxy poly(ethylene glycol) and 2,5-di-tert-pentylhydroquinone. The chemical structures of the novel surfactants are confirmed by 1H NMR, Fourier transform infrared, and gel permeation chromatography (GPC), and their properties such as surface tension, wetting properties, emulsifying properties, and foaming properties are investigated. The surface tension values of S1, S2, and S3 at the critical micelle concentration are 40.29, 37.14, and 41.64 mN/m, exhibiting good surface activity. When the surfactant concentration is higher than 2 mM, the contact angles of S1 and S2 no longer change and can maintain 62 and 64°, showing good wetting properties. In addition, S3 can keep an emulsion state for 2 months at high concentrations, exhibiting good emulsion stability. Furthermore, all the prepared surfactants show good low-foaming properties. The initial foaming volumes of S1 are very low, less than 0.1 mL at various concentrations, less than 2% of the conventional surfactant sodium dodecyl sulfate. For S2, the initial foaming volumes at the concentration of 0.1, 1, 2, and 3 g/L are 1, 0.5, 0.55, and 0.45 mL, respectively. For S3, the initial foaming volumes show a general trend of increasing with concentration. The surfactants with longer poly(oxyethylene) chains possess more initial foaming volumes at the same concentration, which is because the greater cohesion between the surfactant molecules can increase the elasticity of the bubble film. Our study enriches the design rationales for low-foaming surfactants and motivates researchers to develop more advanced surfactants for industrial cleaning and photoresist development.

Microbiological studies on Escherichia coli and Klebsiella pneumoniae causing vaginal and urinary tract inflammation; prevalence, antibiotics-resistance and natural products susceptibility

Great efforts have been made for controlling multidrug-resistant bacteria (MDR). The antibacterial activity of natural products is an effective strategy due to its beneficial effects on human health. This study focused on the isolation, identification, studying the prevalence and the susceptibility of Escherichia coli and Klebsiella spp. to some natural products. After isolation, the isolates primarily identified using biochemical and API tests. Then, the antibiotic susceptibility test was done to reveal the most antibiotics resistant isolates before further identification of Escherichia coli and Klebsiella pneumoniae using phoA and gyrA genes, respectively. Furthermore, the sensitivity of the most antibiotics resistant isolates to apple cider vinegar (ACV), garlic oil (GO), coconut oil (CNO), tea tree oil (TTO), and lavender oil (LO) was estimated. All tested extracts especially ACV and TTO showed good antibacterial activity against MRD selected isolates. Statistical analysis indicated that there was significant difference in ACV and TTO antibacterial response between Escherichia coli and Klebsiella pneumoniae whereas there was no significant difference between natural products activity when tested against Escherichia coli and Klebsiella pneumoniae seperatly. GC-MS spectroscopy analysis revealed the most prominent active constituents present in tested ACV and TTO. Analyzing the 16S rRNA sequence confirmed the two most MRD pathogenic isolates that showed sensitivity to ACV and TTO were Escherichia coli MS1 and Klebsiella pneumoniae MS47, respectively. Essential oils tea tree and apple cider vinegar showed good antibacterial activities against antibiotics-resistant Escherichia coli and Klebsiella pneumoniae causing vaginal and urinary tract inflammation.

Study on biotransformation and absorption of genistin based on fecal microbiota and Caco-2 cell.

Genistin, as a kind of natural isoflavone glycoside, has good biological activity, and its weak absorption makes it closely related to intestinal flora. However, the role of the intestinal flora is still unclear and whether the metabolites produced by the intestinal flora are absorbed systemically is also variable. Genistin was fermented for 24h based on fecal bacteria fermentation technology. The components were qualitatively and quantitatively analyzed by HPLC and UHPLC-Q-Exactive Orbitrap Mass spectrometry. The composition of intestinal flora in fermentation samples from fecal bacteria was detected by 16S rRNA sequencing. Five representative probiotics were cultured in vitro and fermented with genistin to determine similarities and differences in genistin metabolites by different bacteria at different times. Finally, the absorption results of metabolites by fermentation were verified by a Caco-2 cell monolayer. The HPLC results of fecal fermentation showed that genistein levels increased from 0.0139 ± 0.0057mg/mL to 0.0426 ± 0.0251mg/mL and two new metabolites were produced. A total of 46 metabolites following fecal fermentation were identified, resulting from various biotransformation reaction products, such as decarbonylation, hydroxylation, and methylation. Simultaneously, the 16S rRNA results showed that the intestinal flora changed significantly before and after fermentation and that the intestinal microorganisms in the control (Con) group and the fermentation (Fer) group showed a significant separation trend. Five genera, Lactobacillus, Bifidobacterium, Parabacteroides, Sutterella, and Dorea, were considered the dominant flora for genistin fermentation. The qualitative results of fermentation of genistin by five probiotics at different times showed that there were significant differences in small molecule metabolites by fermentation of different bacteria. Meanwhile, most metabolites could be identified following fecal bacteria fermentation, which verified the importance of the dominant bacteria in the feces for the biotransformation of components. Finally, the absorption results of the metabolites based on the Caco-2 cell monolayer showed that 14 metabolites could be absorbed into the circulation in vivo through the mesentery. The small molecule metabolites of genistin by fermentation of fecal bacteria can be well absorbed systemically by the body. These studies provide a reference value for explaining the transformation and absorption of flavonoid glycosides in the intestine.

Multifunctional Au–Ag NCs for luminescence and colorimetric double signal sensing of H2S and catalytic reduction of nitrophenol

In this study, the N-Acetyl-l-Cysteine (NAC)-capped gold and silver bimetallic nanoclusters (NAC@Au–Ag NCs) was synthesized by reflux method. Due to the silver effect, the NAC@Au–Ag NCs exhibited strong photoluminescence at far-red/near-infrared regions and better catalytic performance than Au or Ag NCs. Upon addition of H2S, the Au–Ag NCs exhibited obvious fluorescence quench and color changes through the generation of metal sulfides and a static quenching process. The Au–Ag NCs displayed a wide linear luminescence response for H2S (18.5–217 μmol/L) with a detection limit of 0.269 μmol/L. Moreover, the visible color of Au–Ag NCs changed from white to brown-yellow along with increased H2S, the corresponding RGB values also displayed good linearity with the concentration of H2S (90.1–678 μmol/L). Notably, the fabrication of test strips provided a convenient and intuitive tool to screen the freshness of eggs by the color change of test strips. Au–Ag NCs could be used for living HeLa cells bioimaging and recognition of H2S abnormalities. Furthermore, it can be used as a catalyst to reduction of nitrophenols (NPhs), specific included 2NP, 3NP and 4NP. The reaction was regarded as a pseudo-first-order kinetic reaction due to the presence of excess NaBH4. At 298K, the catalytic rate constants(k) of 2NP, 3NP and 4NP were 0.1754 min−1, 0.1734 min−1 and 0.2782 min−1, respectively. The NAC@Au–Ag NCs catalyst still showed good catalytic activity and reusability after five cycles. Therefore, this study developed a H2S sensor for food samples and biological systems. And this nanocatalyst had great application potential for removed the nitrophenol pollutants in water.

Synergistic action of bacteriophage and metabolites of Pseudomonas fluorescens JB3B and Streptomyces thermocarboxydus 18PM against Enterotoxigenic Escherichia coli and Bacillus cereus and their biofilm

BackgroundFoodborne disease and food spoilage are the prime public health issue and food security round the globe. Significant disease outbreaks mostly linked to the existence of pathogenic bacteria that extremely challenging due to the persistence of biofilm-forming. Proteins and bacterial metabolites have been shown to have good antibacterial activity and effectively removal bacterial biofilm. Recently, bacteriophage and their encoded lytic proteins such as lysin have attracted attention as potential alternative agent to control undesirable pathogens in human body infection, increasing food safety as advance preservations and medical treatment such as phage therapy. For these reasons, the efficacy of bacteriophage and their potential in combination with bacterial metabolites from Phyllosphere and Actinomycetes bacteria (Pseudomonas fluorescens JB3B and Streptomyces thermocarboxydus 18PM crude extracts) was the aim of this present study.ResultsIn this study, bacteriophage BC-VP (1.28 ± 0.29 × 1011 PFU/ml) and ETEC-phage-TG (8.9 ± 2.19 × 108 PFU/ml) isolated from artificial lake water from previous study showed potential activity to control Bacillus cereus (BC) and Enterotoxigenic Escherichia coli (ETEC) population. The combination of BC-VP with metabolite (P. fluorescens JB3B and S. thermocarboxydus 18PM) which were known from previous study had antibiofilm activities were able to inhibit (86.1%; 83.3%) and destruct (41%; 45.5%) biofilm formation of B. cereus respectively. Likewise, the synergy of bacteriophage ETEC-phage-TG with the same crude extract also showed promising activity against biofilm of ETEC with percentage of inhibition (81.9%; 76.4%) and percentage of destruction (54.1%; 44.4%). Application in various food, combination of BC-VP and bacterial metabolite extract (P. fluorescens JB3B; S. thermocarboxydus 18PM) were able to reduce Bacillus cereus population in mashed potato (99.6%; 99.4%) at cold temperature (4 °C) and (68.9%; 56.6%) at room temperature (28 °C), boiled pasta (99.5%; 99.4%) and (84.7%; 75.7%), also soymilk (96.9%; 96.7%) and (42.4%; 39.4%) respectively. Likewise, combination of ETEC-phage-TG and bacterial metabolite (P. fluorescens JB3B; S. thermocarboxydus 18PM) potentially reduced ETEC population after two different temperatures (4 °C and 28 °C) incubation in bean sprouts (TFTC; TFTC) and (47.5%; 49.1%), chicken meat (TFTC; TFTC) and (58.1%; 54%), also minced beef (99.5%; 99.4%) and (41.1%; 28%). GC-MS determination performed, oxalic acid, phenol, phenylethyl alcohol, N-hexadecanoic acid, and pyrolol[1,2-a]pyrazine-1,4-dione, hexadro-3-92-methylpropyl was the most active compound in P. fluorescens JB3B. 2,4-Di-tert-butylphenol, phenyl acetic acid, N-Hexadecanoic acid, pyrolol[1,2-a]pyrazine-1,4-dione, hexadro-3-92-methylpropyl, and Bis(2-ethylhexyl) phthalate was most active compound in the S. thermocarboxydus 18PM isolates.ConclusionsThe combination of isolated bacteriophages and bacterial metabolite showed promising results to be used as biocontrol candidate to overcome biofilm formed by foodborne and food spoilage bacteria using their ability to produce antibiofilm compounds and lytic activity. In addition, this combination also potentially reduces the use or replace the drawbacks of common application such as antibiotic treatment.

Green synthesis, characterization and antibacterial evaluation of ZnO and Ag-doped ZnO nanoparticles using Ruta chalepensis leaf extract

ABSTRACT In this study, a facile, green, and eco-friendly approach was followed for the synthesis of zinc oxide (ZnO), Ag-doped ZnO nanoparticles (NPs) using Ruta chalepensis leaf extract. The biosynthesized nanoparticles were characterized by X-ray diffraction (X-RD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), and ultraviolet–visible spectroscopy (UV-Vis). The UV-Vis absorbance peaks for ZnO, 5%, and 7% Ag-doped ZnO NPs were 357, 360, and 364 nm, with band gaps of 3.00, 2.73, and 2.83 eV, respectively. The XRD data showed average crystalline sizes of ZnO, 5% Ag-doped ZnO, and 7% Ag-doped ZnO NPs were 13.82, 27.50, and 25.92 nm, respectively. The presence of a functional group was confirmed by FTIR spectrum. The improved antibacterial activity of Ag-doped ZnO NPs was due to Reactive Oxygen Species (ROS) formation. The higher zone of inhibition was observed in S. aureus and B. cereus (11 ± 1.0 and 12.33 ± 0.57 mm, respectively), by 7% Ag-doped ZnO NPs. Our finding showed that synthesized Ag-doped ZnO NPs possessed good antibacterial activity as compared to pure ZnO NPs. Hence, the designed plant leaf mediated Ag-doped ZnO NPs synthesis has provided avenues for the enhancement of the high efficiency of its antibacterial activity, this makes the study unique.

A Porphyrin-Based sp2 Carbon-Conjugated covalent organic polymer containing flexible chains for efficient heterogeneous photocatalysis

Porphyrin based covalent organic polymers are excellent catalysts. Herein, a sp2 carbon linked porphyrin based organic polymer H2Pp-PDAN was designed and synthesized by co-condensation of porphyrin monomer containing flexible chains H2Pp with 1, 4-phenylenediacetonitrile PDAN. As photocatalysts, H2Pp-PDAN exhibited excellent photocatalytic performance for photocatalytic oxidative coupling of amines, and was successfully used for 15 consecutive reactions with no detectable reduction of the catalytic activity. H2Pp-PDAN showed good photocatalytic activity and excellent recyclability for photocatalytic oxidation of thioanisole to methyl phenyl sulfoxide. Mechanistic studies revealed that the photocatalytic oxidation of benzylamine coupling by H2Pp-PDAN proceeds via both energy transfer and electron transfer pathways.