Antibacterial, antibiofilm, and anti-adhesion activities of Piper betle leaf extract against Avian pathogenic Escherichia coli

Piper betle leaves have traditionally been used to treat many diseases, including bacterial infections. The present studyaimed to investigate the antibacterial, antibiofilm, and anti-adhesion activities of P. betle extract against avian pathogenicEscherichia coli (APEC). The ethanol extract of P. betle leaves demonstrated strong antibacterial activity against clinicalisolates of APEC with MIC and MBC values ranging from 0.5 to 1.0 mg/mL as compared with 1% DMSO, a negative control.Disruption and breakdown of the bacterial cells were detected when the cells were challenged with the extract at 2 × MIC.Bacterial cells treated with the extract demonstrated longer cells without a septum, compared to the control. The extract at1/8, 1/4, and 1/2× MIC significantly inhibited the formation of the bacterial biofilm of all the tested isolates except the iso-late CH10 (P < 0.05) without inhibiting growth. At 1/2 × MIC, 55% of the biofilm inhibition was detected in APEC CH09,a strong biofilm producer. At 32 × MIC, 88% of the inhibition of viable cells embedded in the mature biofilm was detectedin APEC CH09. Reduction in the bacterial adhesion to surfaces was shown when APEC were treated with sub-MICs of theextract as observed by SEM. Hydroxychavicol was found to be the major compound presented in the leaf extract as detectedby GC–MS analysis. The information suggested potential medicinal benefits of P. betle extract to inhibit the growth, biofilm,and adhesion of avian pathogenic E. coli.publishe

Anti-Acanthamoeba activity of a semi-synthetic mangostin derivative and its ability in removal of Acanthamoeba triangularis WU19001 on contact lens

Garcinia mangostana L., also known as the mangosteen tree, is a native medicinal plant in Southeast Asia having a wide variety of pharmacologically active compounds, including xanthonoid mangostin. In this study, we examined the pharmacological activities of the selected semi-synthetic mangostin derivative, namely, amoebicidal activity, encystation inhibition, excystation activity, and removal capacity of adhesive Acanthamoeba from the surface of contact lens (CL). Among the three derivatives, C1 exhibited promising anti-Acanthamoeba activity against Acanthamoeba triangularis WU19001 trophozoites and cysts. SEM images displayed morphological changes in Acanthamoeba trophozoites, including the loss of acanthopodia, pore formation in the cell membrane, and membrane damage. In addition, the treated cyst was shrunken and adopted an irregular flat cyst shape. Under a fluorescence microscope, acridine orange and propidium iodide (AO/PI) staining revealed C1 induced condensation of cytoplasm and chromatin with the loss of cell volume in the treated trophozoites, while calcofluor white staining demonstrated the leakage of cell wall in treated cysts, leading to cell death. Interestingly, at the concentration ranges in which C1 showed the anti-Acanthamoeba effects (IC50 values ranging from 0.035–0.056 mg/mL), they were not toxic to Vero cells. C1 displayed the highest inhibitory effect on A. triangularis encystation at 1/16×MIC value (0.004 mg/mL). While C1 demonstrated the excystation activity at 1/128×MIC value with a high rate of 89.47%. Furthermore, C1 exhibited the removal capacity of adhesive Acanthamoeba from the surface of CL comparable with commercial multipurpose solutions (MPSs). Based on the results obtained, C1 may be a promising lead agent to develop a therapeutic for the treatment of Acanthamoeba infections and disinfectant solutions for CL

Targeting Acanthamoeba proteins interaction with flavonoids of Propolis extract by in vitro and in silico studies for promising therapeutic effects

Background: Propolis is a natural resinous mixture produced by bees. It provides beneficial effects on human health in the treatment/management of many diseases. The present study was performed to demonstrate the anti-Acanthamoeba activity of ethanolic extracts of Propolis samples from Iran. The interactions of the compounds and essential proteins of Acanthamoeba were also visualized through docking simulation. Methods: The minimal inhibitory concentrations (MICs) of Propolis extract against Acanthamoeba trophozoites and cysts was determined in vitro. In addition, two-fold dilutions of each of agents were tested for encystment, excystment and adhesion inhibitions. Three major compounds of Propolis extract such as chrysin, tectochrysin and pinocembrin have been selected in molecular docking approach to predict the compounds that might be responsible for encystment, excystment and adhesion inhibitions of A. castellanii. Furthermore, to confirm the docking results, molecular dynamics (MD) simulations were also carried out for the most promising two ligand-pocket complexes from docking studies. Results: The minimal inhibitory concentrations (MICs) 62.5 and 125 µg/mL of the most active Propolis extract were assessed in trophozoites stage of Acanthamoeba castellanii ATCC30010 and ATCC50739, respectively. At concentrations lower than their MICs values (1/16 MIC), Propolis extract revealed inhibition of encystation. However, at 1/2 MIC, it showed a potential inhibition of excystation and anti-adhesion. The molecular docking and dynamic simulation revealed the potential capability of Pinocembrin to form hydrogen bonds with A. castellanii Sir2 family protein (AcSir2), an encystation protein of high relevance for this process in Acanthamoeba. Conclusions: The results provided a candidate for the development of therapeutic drugs against Acanthamoeba infection. In vivo experiments and clinical trials are necessary to support this claim

Blend film based on fish gelatine/curdlan for packaging applications: spectral, microstructural and thermal characteristics

A series of novel fish gelatine/curdlan (FG/CL) blend films at different ratios (FG/CL ≈ 10:0, 8:2, 6:4, 5:5 and 0:10%, w/w) were successfully fabricated at pH 12 via a casting approach, and their physico-mechanical, spectral, microstructural and thermal properties were investigated as a function of CL content. FG/CL blend films exhibited lower tensile strength (TS) but higher elongation at break (EAB) and water vapour permeability (WVP), compared to FG film (P < 0.05). Increased contact angle () and moisture content (MC), but decreased water solubility (WS) were obtained for FG/CL blend films having the higher proportion of CL (P < 0.05). Furthermore, the addition of CL decreased a∗-(redness) and transparency values (P < 0.05), but enhanced L∗-(lightness), b∗-(yellowness) and ΔE∗-values (total colour difference) (P < 0.05) in FG/CL blend films. Light transmission in ultraviolet (UV) and visible regions (200-800 nm) was lowered in all FG/CL blend films, indicating excellent light barrier characteristics. Significant changes in molecular order and decreased intermolecular interactions in the matrix of FG/CL blend film were determined based on FTIR spectroscopy. TGA and DTG curves displayed that FG/CL (8:2) blend film had enhanced heat stability as evidenced by higher heat-stable mass residues (34.1%, w/w), compared to FG film (26.6%, w/w) in the temperature range of 50-600 °C. DSC thermogram suggested the solid-state morphology of FG/CL (8:2) blend film that consisted of amorphous/microcrystalline phase of partially miscible FG/CL aggregated junction zones and the coexisting of unbound CL domains. SEM micrographs elucidated that FG/CL (8:2) blend film was slightly rougher than FG film, but no signs of phase separation between film components were observed, thereby confirming its prospective use as food packaging material

Characterisation of composite films fabricated from collagen/chitosan and collagen/soy protein isolate for food packaging applications

This study was undertaken to evaluate the potential of collagen/chitosan (CG/CH) and collagen/soy protein isolate (CG/SPI) composite films for food packaging applications. Two types of composite films at different blend ratios of CG/CH or CG/SPI (10 : 0, 8 : 2, 6 : 4, 5 : 5 and 0 : 10%, w/w) using 30% (w/w) glycerol as plasticiser were prepared and characterised. The results of mechanical tests of the CG/CH composite films displayed higher elongation at break point (EAB), but lower tensile strength (TS) and modulus of elasticity (E), compared to the CG film (P < 0.05). Conversely, the CG/SPI composite films exhibited lower EAB, but greater TS and E values (P < 0.05) compared to the CG film. Water vapour permeability (WVP) increased markedly in the CG/CH composite films; whilst it was found to decrease in CG/SPI composite films at the different blend ratios tested (P < 0.05). Transparency values and water solubility of CG/CH and CG/SPI composite films were decreased substantially, compared to the CG film (P < 0.05). Lower light transmission was observed in all composite films in ultraviolet (UV) and visible regions (200–800 nm), indicating improved UV blocking capacity. Intermolecular interactions through hydrogen bonding among polymeric components were dominant in the CG/SPI (8 : 2) composite film as elucidated by FTIR analysis. Thermo-gravimetric curves demonstrated that CG/CH (8 : 2) and CG/SPI (8 : 2) composite films exhibited lower heat susceptibility and weight loss (%), as compared to the CG film in the temperature range of 30–600 °C. DSC thermograms suggested that the compatible blend of CG/SPI (8 : 2) rendered a solid film matrix, which consisted of highly ordered and aggregated junction zones. SEM micrographs revealed that both CG/CH (8 : 2) and CG/SPI (8 : 2) composite films were slightly rougher than the CG film, but no apparent signs of cracking and layering phenomena were observed, thereby highlighting their potential use as biodegradable packaging materials

Approach toward enhancement of halophilic protease production by Halobacterium sp. strain LBU50301 using statistical design response surface methodology

A new potent halophilic protease producer, Halobacterium sp. strain LBU50301 was isolated from salt-fermented fish samples (budu) and identified by phenotypic analysis, and 16S rDNA gene sequencing. Thereafter, sequential statistical strategy was used to optimize halophilic protease production from Halobacterium sp. strain LBU50301 by shake-flask fermentation. The classical one-factor-at-a-time (OFAT) approach determined gelatin was the best nitrogen source. Based on Plackett–Burman (PB) experimental design; gelatin, MgSO4·7H2O, NaCl and pH significantly influenced the halophilic protease production. Central composite design (CCD) determined the optimum level of medium components. Subsequently, an 8.78-fold increase in corresponding halophilic protease yield (156.22 U/mL) was obtained, compared with that produced in the original medium (17.80 U/mL). Validation experiments proved the adequacy and accuracy of model, and the results showed the predicted value agreed well with the experimental values. An overall 13-fold increase in halophilic protease yield was achieved using a 3 L laboratory fermenter and optimized medium (231.33 U/mL)

Conserved Candidate Antigens and Nanoparticles to Develop Vaccine against <i>Giardia intestinalis</i>

Giardia intestinalis (Giardia lambia, Giardia duodenalis) infections in humans may be asymptomatic or symptomatic and associated with diarrhea (without blood), abdominal cramps, bloating, flatulence, and weight loss. The protozoan Giardia is the third most common cause of diarrhea and death in children under five, preceded only by rotavirus and by Cryptosporidium parvum and C. hominis infections. Antimicrobial drugs, particularly 5-nitroimidazole (5-NIs), are used to treat giardiasis in humans. Immunologically naive or immunocompromised host are more vulnerable to Giardia infection, whereas a degree of resistance to this protozoan is present in humans living in endemic areas. This suggests that vaccination may be a potential and appropriate means to control this parasitic disease outbreak and protect the human population. This review discusses Giardia antigens related to vaccine development. Additionally, based on the latest development of nanoparticle technology, a combination of methods for future research and development is proposed for the design of the next generation of powerful immunogens and an effective vaccine against Giardia

Targeting Acanthamoeba proteins interaction with flavonoids of Propolis extract by in vitro and in silico studies for promising therapeutic effects [version 2; peer review: 2 approved]

Background: Propolis is a natural resinous mixture produced by bees. It provides beneficial effects on human health in the treatment/management of many diseases. The present study was performed to demonstrate the anti-Acanthamoeba activity of ethanolic extracts of Propolis samples from Iran. The interactions of the compounds and essential proteins of Acanthamoeba were also visualized through docking simulation. Methods: The minimal inhibitory concentrations (MICs) of Propolis extract against Acanthamoeba trophozoites and cysts was determined in vitro. In addition, two-fold dilutions of each of agents were tested for encystment, excystment and adhesion inhibitions. Three major compounds of Propolis extract such as chrysin, tectochrysin and pinocembrin have been selected in molecular docking approach to predict the compounds that might be responsible for encystment, excystment and adhesion inhibitions of A. castellanii. Furthermore, to confirm the docking results, molecular dynamics (MD) simulations were also carried out for the most promising two ligand-pocket complexes from docking studies. Results: The minimal inhibitory concentrations (MICs) 62.5 and 125 µg/mL of the most active Propolis extract were assessed in trophozoites stage of Acanthamoeba castellanii ATCC30010 and ATCC50739, respectively. At concentrations lower than their MICs values (1/16 MIC), Propolis extract revealed inhibition of encystation. However, at 1/2 MIC, it showed a potential inhibition of excystation and anti-adhesion. The molecular docking and dynamic simulation revealed the potential capability of Pinocembrin to form hydrogen bonds with A. castellanii Sir2 family protein (AcSir2), an encystation protein of high relevance for this process in Acanthamoeba. Conclusions: The results provided a candidate for the development of therapeutic drugs against Acanthamoeba infection. In vivo experiments and clinical trials are necessary to support this claim