Anti-pathogenic Effects Research Articles

Biosynthesis of silver nanoparticles from Arum dioscoridis plant leaf aqueous extract: anticancer and antimicrobial properties

This study was carried out to synthesize silver nanoparticles (AgNPs) from Arum dioscoridis (AD) leaf extract and to investigate the cytotoxic and antipathogenic effects of them. The plant material had a reducing and stabilizing effect on the synthesized nanomaterial. During the plant-mediated synthesis of nanomaterials, no substances that would cause environmental pollution were used. For the structural characterization of AD-AgNPs, Ultraviolet-visible (UV-vis) Spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Electron Dispersive X-ray (EDX) Spectroscopy, Fourier Transform Infrared (FT-IR) Spectroscopy, Transmission Electron Microscopy (TEM), X-ray Diffractometer (XRD), Atomic Force Microscopy (AFM) and Zetasizer analyses were performed. The produced AgNPs showed maximum surface plasmon resonance at 431.67 nm and had mostly spherical morphology. The zeta potential value of the nanomaterial was -9.76 mV and the average powder crystal size was 31.48 nm. The minimum inhibitory concentration (MIC) values (mg/L) of AD-AgNPs on Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Candida albicans were 0.25, 2.00, 0.125, 4.00, and 1.00, respectively. After 24 and 48 hours of application by MTT [3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazolium bromid] assay, the half-maximal inhibitory concentrations (IC50: μg/mL) of AD-AgNPs on human colon adenocarcinoma cell (CACO-2), human breast cancer cell (MCF-7), glioblastoma multiforme cell (T98-G), and healthy human umbilical vein endothelial cell (HUVEC) lines were determined as 2.977, 2.801, 5.694, 4.392; 2.115, 2.300, 2.612, 4.091, respectively.

Modulation of the Host Response as a Therapeutic Strategy in Severe Lung Infections.

Respiratory pathogens such as influenza and SARS-CoV-2 can cause severe lung infections leading to acute respiratory distress syndrome (ARDS). The pathophysiology of ARDS includes an excessive host immune response, lung epithelial and endothelial cell death and loss of the epithelial and endothelial barrier integrity, culminating in pulmonary oedema and respiratory failure. Traditional approaches for the treatment of respiratory infections include drugs that exert direct anti-pathogen effects (e.g., antivirals). However, such agents are typically ineffective or insufficient after the development of ARDS. Modulation of the host response has emerged as a promising alternative therapeutic approach to mitigate damage to the host for the treatment of respiratory infections; in principle, this strategy should also be less susceptible to the development of pathogen resistance. In this review, we discuss different host-targeting strategies against pathogen-induced ARDS. Developing therapeutics that enhance the host response is a pathogen-agnostic approach that will help prepare for the next pandemic.

Antimicrobial and antivirulence saponins of Mimusops laurifolia leaves.

Mimusops laurifolia is a native species restricted to the Red Sea mountains and Gulf of Aden. Its leaves contain saponins with wide range of biological activities. The presented research aimed to prepare saponins-rich extract from n-butanol fraction of M. laurifolia leaves and screen it for promising antimicrobial activities. Minimum inhibitory concentration (MIC) of the prepared saponins against Candida albicans, and their potential anti-pathogenic and antivirulence effects were determined. Different concentrations of the saponins-rich extract were investigated for their antimicrobial potential, particularly against C. albicans, using the agar well diffusion method. To assess the potential antivirulence and anti-pathogenic effects, we carried out molecular docking of the bioactive saponins against four key enzymes in C. albicans, which are involved in virulence and/or pathogenicity. Different concentrations of the investigated mixture showed notable antifungal activity against C. albicans with an MIC value of 6.4μg ml-1. Docking analysis of the investigated saponins showed their affinity toward the docked enzymes, particularly saponin 1 with secreted aspartic proteinase 3 and saponin 6 with secreted aspartic proteinase 5. Thereafter, the stability of these two protein-ligand interactions was investigated using molecular dynamics (MD) simulation. The molecular interactions between saponins and the enzymes' active sites were analyzed and discussed.

Sunflower spines and beyond: Mechanisms and breadth of pollen that reduce gut pathogen infection in the common eastern bumble bee

Abstract Plants have unique chemical and physical traits that can reduce infections in animals ranging from primates to caterpillars. Sunflowers (Helianthus annuus; Asteraceae) are one striking example, with pollen that suppresses infections by the trypanosomatid gut pathogen Crithidia bombi in the common eastern bumble bee (Bombus impatiens). However, the mechanism underlying this effect has remained elusive, and we do not know whether pollens from other Asteraceae species have similar effects. We evaluated whether mechanisms mediating sunflower pollen's antipathogenic effects are physical (due to its spiny exine), chemical (due to metabolites) or both. We also evaluated the degree to which pollen from seven other Asteraceae species reduced C. bombi infection relative to pollen from sunflower and two non‐Asteraceae species, and whether pollen spine length predicted pathogen suppression. We found that sunflower exines alone reduced infection as effectively as whole sunflower pollen, while sunflower pollen metabolites did not. Furthermore, bees fed pollen from four of seven other Asteraceae had 62%–92% lower C. bombi infections than those fed non‐Asteraceae pollen. Spine length, however, did not explain variation in bumble bee infection. Our study indicates that sunflower pollen's capacity to suppress C. bombi is driven by its spiny exine, and that this phenomenon extends to several other Asteraceae species. Our results indicate that sunflower pollen exines are as effective as whole pollen in reducing infection, suggesting that future studies should expand to assess the effects of other species with spiny pollen on pollinator–pathogen dynamics. Read the free Plain Language Summary for this article on the Journal blog.

Disease alleviating effects following prophylactic lemon and coriander essential oil treatment in mice with acute campylobacteriosis.

Given the worldwide increasing prevalence of human Campylobacter jejuni infections and the emergence of multi-drug resistant enteropathogenic strains, antibiotic-independent approaches applying non-toxic natural compounds for the treatment and prophylaxis of campylobacteriosis appear utmost desirable. In our placebo-controlled intervention study, we surveyed potential disease-alleviating including anti-pathogenic and immune-modulatory effects upon prophylactic oral application of lemon-essential oil (LEM-EO) and coriander-essential oil (COR-EO) in acute experimental campylobacteriosis. Therefore, secondary abiotic IL-10-/- mice were orally challenged with either LEM-EO or COR-EO starting seven days prior to peroral C. jejuni infection. Six days post-infection, slightly lower pathogen loads were assessed in the colon of mice from the LEM-EO as opposed to the COR-EO cohort if compared to placebo counterparts. Prophylactic application of both EOs improved the clinical outcome of acute campylobacteriosis which was paralleled by less distinct pathogen-induced colonic epithelial cell apoptosis. Moreover, mice subjected to LEM-EO and COR-EO prophylaxis displayed lower colonic numbers of macrophages/monocytes and of T lymphocytes, respectively, whereas in both verum groups, basal IL-6 and IFN-γ concentrations were measured in mesenteric lymph nodes on day 6 post-infection. The oral challenge with either EOs resulted in diminished secretion of distinct pro-inflammatory mediators in the kidney as well as serum samples derived from the infected mice. In conclusion, the results from our preclinical in vivo study provide evidence that LEM-EO and COR-EO constitute promising prophylactic measures to prevent severe campylobacteriosis which may help to reduce the risk for development of post-infectious sequelae in C. jejuni infected individuals.

Comparing the Effects of Rocaglates on Energy Metabolism and Immune Modulation on Cells of the Human Immune System.

A promising new approach to broad spectrum antiviral drugs is the inhibition of the eukaryotic translation initiation factor 4A (elF4A), a DEAD-box RNA helicase that effectively reduces the replication of several pathogenic virus types. Beside the antipathogenic effect, modulation of a host enzyme activity could also have an impact on the immune system. Therefore, we performed a comprehensive study on the influence of elF4A inhibition with natural and synthetic rocaglates on various immune cells. The effect of the rocaglates zotatifin, silvestrol and CR-31-B (-), as well as the nonactive enantiomer CR-31-B (+), on the expression of surface markers, release of cytokines, proliferation, inflammatory mediators and metabolic activity in primary human monocyte-derived macrophages (MdMs), monocyte-derived dendritic cells (MdDCs), T cells and B cells was assessed. The inhibition of elF4A reduced the inflammatory potential and energy metabolism of M1 MdMs, whereas in M2 MdMs, drug-specific and less target-specific effects were observed. Rocaglate treatment also reduced the inflammatory potential of activated MdDCs by altering cytokine release. In T cells, the inhibition of elF4A impaired their activation by reducing the proliferation rate, expression of CD25 and cytokine release. The inhibition of elF4A further reduced B-cell proliferation, plasma cell formation and the release of immune globulins. In conclusion, the inhibition of the elF4A RNA helicase with rocaglates suppressed the function of M1 MdMs, MdDCs, T cells and B cells. This suggests that rocaglates, while inhibiting viral replication, may also suppress bystander tissue injury by the host immune system. Thus, dosing of rocaglates would need to be adjusted to prevent excessive immune suppression without reducing their antiviral activity.

A comprehensive review of the application of probiotics and postbiotics in oral health.

Oral diseases are among the most common diseases around the world that people usually suffer from during their lifetime. Tooth decay is a multifactorial disease, and the composition of oral microbiota is a critical factor in its development. Also, Streptococcus mutans is considered the most important caries-causing species. It is expected that probiotics, as they adjust the intestinal microbiota and reduce the number of pathogenic bacteria in the human intestine, can exert their health-giving effects, especially the anti-pathogenic effect, in the oral cavity, which is part of the human gastrointestinal tract. Therefore, numerous in vitro and in vivo studies have been conducted on the role of probiotics in the prevention of tooth decay. In this review, while investigating the effect of different strains of probiotics Lactobacillus and Bifidobacteria on oral diseases, including dental caries, candida yeast infections, periodontal diseases, and halitosis, we have also discussed postbiotics as novel non-living biological compounds derived from probiotics.

Physiological aspect of apoptosis-regulating microRNAs expressions during fasting.

Fasting is an activity that requires a certain calorie restriction without consuming food or drinks for a certain period of daytime. However, fasting triggers many complex events, including activating cellular stress response pathways, autophagy promotion, apoptosis pathways, and a change in hormonal balance. Among the many events affecting the regulation of apoptosis, the expression of microRNAs (miRNAs) plays an important role. Therefore, we aimed to investigate the levels and importance of miRNA expression in fasting. The expressions of 19 miRNAs regulating different pathways from saliva samples, isolated by matching healthy university students (n = 34) as group 1 (fasting for 17 consecutive hours) and group 2 (testing 70 minutes after meal consumption), were examined using the real-time PCR method. In fasting, modulation of apoptotic pathways by miRNAs triggers anti-pathogenic effects, and the adaptation of abnormal cells in the body decreases. For this reason, vital diseases, such as cancer, can be treated by preventing the proliferation and growth of cancerous cells by increasing programmed cell death due to the downregulation expression mechanism of miRNAs. Our study aims to improve the knowledge about the mechanisms and functions of miRNAs in various apoptosis pathways during fasting and may be a model for further future physiological and pathological studies.

Molecular Targets in Campylobacter Infections

Human campylobacteriosis results from foodborne infections with Campylobacter bacteria such as Campylobacter jejuni and Campylobacter coli, and represents a leading cause of bacterial gastroenteritis worldwide. After consumption of contaminated poultry meat, constituting the major source of pathogenic transfer to humans, infected patients develop abdominal pain and diarrhea. Post-infectious disorders following acute enteritis may occur and affect the nervous system, the joints or the intestines. Immunocompromising comorbidities in infected patients favor bacteremia, leading to vascular inflammation and septicemia. Prevention of human infection is achieved by hygiene measures focusing on the reduction of pathogenic food contamination. Molecular targets for the treatment and prevention of campylobacteriosis include bacterial pathogenicity and virulence factors involved in motility, adhesion, invasion, oxygen detoxification, acid resistance and biofilm formation. This repertoire of intervention measures has recently been completed by drugs dampening the pro-inflammatory immune responses induced by the Campylobacter endotoxin lipo-oligosaccharide. Novel pharmaceutical strategies will combine anti-pathogenic and anti-inflammatory effects to reduce the risk of both anti-microbial resistance and post-infectious sequelae of acute enteritis. Novel strategies and actual trends in the combat of Campylobacter infections are presented in this review, alongside molecular targets applied for prevention and treatment strategies.

Quinoline alkaloids from the roots of Orixa japonica with the Anti-pathogenic Fungi Activities.

A new quinoline alkaloid, 5-hydroxy-6-methoxy-N-methyl-2-phenylquinoline-4-one (1), and seventeen known quinoline alkaloids (2-18) were isolated from the roots of Orixa japonica. The structure of 1 was determined by analysis of spectroscopic data. Among them, compounds 2, 3, and 13 were isolated from this plant for the first time. All isolates were screened for the anti-pathogenic fungi activities, including Rhizoctonia solani, Magnaporthe oryzae, and Phomopsis sp.. The results showed that five compounds (4, 8, 10, 11, and 12) exhibited significant anti-pathogenic fungi effects at 50.0 μg/mL. In special, compound 10 exhibited the best antifungal activities toward R. solani and M. oryzae with the IC50 values of 37.86 and 44.72 μM, respectively, better than that of the positive control, hymexazol (IC50 121.21 and 1518.18 μM, respectively). Moreover, eleven new quinoline alkaloids derivatives (12a-12k) were designed and synthesized to investigate the structure-activity relationships (SARs). The SARs analysis indicated that the furo [2, 3-b] quinoline skeleton and the methoxy at C-7 (compounds 8, 11, and 12) played a key role for improving the antifungal activities.

Copper-Treated Environmentally Friendly Antipathogenic Cotton Fabric with Modified Reactive Blue 4 Dye to Improve Its Antibacterial and Aesthetic Properties

The objectives of the present study were to develop an environmentally friendly, low-price, easy, and fast method for developing antipathogenic (antibacterial, antifungal, and antiviral) cuprous-oxide-coated multifunctional fabrics. The fabrics were first sensitized with citric acid, and then Cu2O particles were formed using the Fehling solution method. The cuprous oxide particles were then applied to the cotton fabrics. To create the Cu2O particles, three different kinds of reducing agents with varying concentrations were used. SEM, dynamic light scattering, FTIR, EDS, and XRD were used to examine the surface morphologies and metal presences. In the second step, a reactive antibacterial dye was made (by reacting Reactive Blue 4 with triclosan). The molecular structure of the modified dye was confirmed with FTIR. The resultant antibacterial dye was applied on the copper-treated cotton fabrics in accordance with the exhaust dyeing protocol. The dyed fabrics were characterized through the colorimetric data (L*, a*, b*, C, H, and K/S), levelness of dye, fastness properties as well as exhaustion and fixation rates. Cuprous-oxide-coated fabrics were tested for antipathogenic activity using quantitative and qualitative measurement results. The fabrics treated with cuprous oxide particles reduced with sodium hydrosulfite at 1 g/L seemed to have the highest antipathogenic effect. Moreover, the versatility of the hygienically developed bioactive fabrics in terms of their comfort properties such as air permeability and stiffness were investigated. Finally, the coating’s durability was confirmed by evaluating its antibacterial properties and performing an SEM analysis after laundry.

Persicaria amphibia, an old traditional remedy and wild edible herb: In vitro evaluation of cytotoxicity and antimicrobial properties

Persicaria amphibia (subfam. Polygonoideae), an aquatic macrophyte rich in dietary polyphenolics, is used as a traditional remedy and culinary herb. Nevertheless, P. amphibia from the Balkan region has been insufficiently studied and underutilized. Here, the cytotoxicity and antimicrobial properties of the previously chemically characterised ethanol extract of P. amphibia aerial parts were tested. The following methods were carried out: the MTT assay, qRT-PCR, microdilution assay, Chromobacterium violaceum screening assay (monitoring of quorum sensing, QS) and the agar plating method (antifungal activity). The study was conducted to determine the cytotoxic effects of P. amphibia against lung cancer cells (A549) and its combination with cytostatic doxorubicin (Dox). A dose-dependent decrease in cell viability (up to 82% reduction) and additive interactions of the tested agents were noted. Both alone and combined with Dox, P. amphibia reduced the expression of Nrf2 (p < 0.05). In terms of antimicrobial effects, P. amphibia exhibited an antipathogenic effect since it disrupted QS communication, which was evident through the inhibition of violacein production of C. violaceum CV025. The antifungal screening revealed that P. amphibia induced significant growth inhibition of Aspergillus spp. (28.23%). Based on the obtained results, further examination of the potential use of P. amphibia in modern phytotherapy and diet-derived cancer chemoprevention is encouraged.

臭氧杀菌技术在农业和食品行业中的应用：综述

Ozone is a strong oxidant and strong disinfectant that has a strong anti-pathogenic effect on bacteria, fungi, parasites, and viruses. Because of its high reactivity, strong permeability, low residue, and other advantages, the application of ozone is gaining more and more attention, and ozone has been widely used in water treatment, equipment disinfection, public scene disinfection, and other fields. The purpose of this review is to discuss the use of ozone technology for animal and plant protection that can be applied to agriculture, and to emphasize the need for further studies to determine the optimal concentration and application of ozone for different crops so that, in the future, ozone technology can be applied in agriculture to gain a significant competitive advantage and improve product safety.

The Prebiotic Effect of an Organic Acid Mixture on Faecalibacterium prausnitzii Metabolism and Its Anti-Pathogenic Role against Vibrio parahaemolyticus in Shrimp.

Increasing the abundance of probiotic bacteria in the gut requires either direct dietary supplementation or the inclusion of feed additives able to support the growth of beneficial commensal bacteria. In crustaceans, the increased presence of probiotic-like bacteria in the gut, including of Faecalibacterium prausnitzii (F. prausnitzii), will guarantee a positive health status and a gut environment that will ensure enhanced performance. The aim of this study was to investigate if a mixture of organic acids, AuraAqua (Aq) can stimulate the growth and the anti-pathogenic efficacy of F. prausnitzii through a combination of in vitro and ex vivo models. The results showed that 0.5% Aq was able to improve the growth rate of F. prausnitzii in vitro and in an ex vivo shrimp gut model. Moreover, we were able to demonstrate that Aq increases butyrate production and cellulose degradation in culture or in the shrimp gut model. The growth-stimulating effect of Aq also led to an improved and anti-pathogenic effect against Vibrio parahaemolyticus in a co-culture experiment with shrimp gut primary epithelial cells (SGP). In conclusion, our work demonstrates that Aq can stimulate the growth of F. prausnitzii, increase the production of short-chain fatty acid (SCFA) butyrate, improve substrate digestion, and prevent V. parahaemolyticus invasion of SGP cells.

Pattern recognition receptor mediated innate immune response requires a Rif-dependent pathway

Small GTPases play critical roles in cell morphology, movement, and adhesion by dynamic regulation of actin cytoskeleton. The small Rho GTPase Rif/RhoF (Rho in filopodia) regulates the formation of filopodia and stress fibers in cells. Rif is highly expressed in a number of cell types in the immune system; however, it's role in immune system function is unclear. In this research, we found that Rif expression is necessary for NF-κB activation in primary immune cells, and mature dendritic cell (mature DCs) induced from Bone Marrow-Derived Dendritic Cells (BMDCs) isolated from Rif knock out (Rif KO) mice displayed impaired degradation of I-κBα, as well as reduced TNF-α secretion and p38 MAPK phosphorylation under LPS stimulation. Interestingly, we revealed that TLR agonists, such as LPS and poly (I:C), as well as bacterial virulence factor SopE could induce a transient increase in Rif activation in monocytes THP-1 cells. Furthermore, Rif was found to be an integral part of the TLR4, TLR3 and nodosome signaling complex. We further identified Src tyrosine kinases as upstream activator of Rif in both bacterial and viral induced immune responses. Moreover, activated Rif induces activation of transcription factors, such as NF-κB, AP-1 and IRF-3, and mediates inflammation through secretion of IL-6, IL-8 or TNFα. Rif activation by PRRs contributes in a variety of ways to protective host responses against invading microbes. Taken together, this study reveals that Rif is indispensable for both extracellular and intracellular pattern-recognition receptor-mediated innate immune responses. Rif possess broad anti-pathogenic effect and understanding of the molecular mechanisms by which this small Rho GTPase interferes with innate immune system will be beneficial to develop therapies against infectious agents.

Evaluation of the gut microbiome alterations in healthy rats after dietary exposure to different synthetic ZnO nanoparticles

AimsAlthough synthetic ZnO nanoparticles (Nano-ZnO) as an alternative of ZnO compounds have been extensively used such as in livestock production, the increased consuming of Nano-ZnO has raised considerable concerns in environmental pollution and public health. Because of the low digestion of Nano-ZnO, the systematic studies on their interactions with gut microbiota remain to be clarified. Materials and methodsNano-ZnOs were prepared by co-precipitation (ZnO-cp) and high temperature thermal decomposition (ZnO-td) as well as the commercial type (ZnO-s). Transmission electron microscopy (TEM) was used to monitor the morphology of Nano-ZnO. CCK-8 assay was used for cytotoxicity evaluation. Total antioxidant capacity assay, total superoxide dismutase assay, and lipid peroxidation assay were used to evaluate oxidative states of rats. 16S rRNA was used to study the impact of Nano-ZnO on the rat gut microbiome. Key findingsBoth ZnO-cp and ZnO-td exhibited low cytotoxicity while ZnO-s and ZnO-td exhibited prominent antibacterial activities. After a 28-day oral feeding with 1000 mg/kg Zn at dietary dosage, ZnO-s showed slight effect on causing oxidative stress in comparison with that of ZnO-cp and ZnO-td. Results of 16S rRNA sequencing analysis indicated that ZnO-td as a promising short-term nano-supplement can increase probiotics abundances like strains belonged to the genus Lactobacillus and provide the antipathogenic effect. SignificanceThe results of the gut microbiome alteration by synthetic Nano-ZnO not only provide solution to exposure monitoring of environmental hazard, but rationalize their large-scale manufacture as alternative additive in the food chain.

Contribution of Lactobacilli on Intestinal Mucosal Barrier and Diseases: Perspectives and Challenges of Lactobacillus casei.

The intestine barrier, the front line of normal body defense, relies on its structural integrity, microbial composition and barrier immunity. The intestinal mucosal surface is continuously exposed to a complex and dynamic community of microorganisms. Although it occupies a relatively small proportion of the intestinal microbiota, Lactobacilli has been discovered to have a significant impact on the intestine tract in previous studies. It is undeniable that some Lactobacillus strains present probiotic properties through maintaining the micro-ecological balance via different mechanisms, such as mucosal barrier function and barrier immunity, to prevent infection and even to solve some neurology issues by microbiota-gut-brain/liver/lung axis communication. Notably, not only living cells but also Lactobacillus derivatives (postbiotics: soluble secreted products and para-probiotics: cell structural components) may exert antipathogenic effects and beneficial functions for the gut mucosal barrier. However, substantial research on specific effects, safety and action mechanisms in vivo should be done. In clinical application of humans and animals, there are still doubts about the precise evaluation of Lactobacilli's safety, therapeutic effect, dosage and other aspects. Therefore, we provide an overview of central issues on the impacts of Lactobacillus casei (L. casei) and their products on the intestinal mucosal barrier and some diseases and highlight the urgent need for further studies.

Safety Evaluation by Phenotypic and Genomic Characterization of Four Lactobacilli Strains with Probiotic Properties.

Probiotic Lactobacillus species are known to exert health benefits in hosts when administered in adequate quantities. A systematic safety assessment of the strains must be performed before the Lactobacillus strains can be designated as probiotics for human consumption. In this study, we selected Lactobacillus fermentum IDCC 3901, L. gasseri IDCC 3101, L. helveticus IDCC 3801, and L. salivarius IDCC 3551 as representative Lactobacilli probiotic strains and investigated their probiotic properties and potential risks through phenotypic and genomic characterization. Various assays including antimicrobial resistance, biogenic amine production, L-/D-lactate production, acute oral toxicity, and antipathogenic effect were performed to evaluate the safety of the four Lactobacillus strains. Genomic analysis using whole genome sequencing was performed to investigate virulence and antibiotic resistance genes in the genomes of the selected probiotic strains. The phenotypes of the strains such as enzymatic activity and carbohydrate utilization were also investigated. As a result, antibiotic resistances of the four Lactobacillus species were detected; however, neither antibiotic resistance-related genes nor virulence genes were found by genomic analysis. Moreover, the four Lactobacillus species did not exhibit hemolytic activity or β-glucuronidase activity. The biogenic amine production and oral acute toxicity were not shown in the four Lactobacillus species, whereas they produced D-lactate with minor ratio. The four Lactobacillus species exhibited antipathogenic effect to five pathogenic microorganisms. This study provides a way to assess the potential risks of four different Lactobacillus species and validates the safety of all four strains as probiotics for human consumption.

Inhibition of individual and combination of cell free supernatants of phenyllactic acid, pediocin‐ and nisin‐producing lactic acid bacteria against food pathogens and bread spoilage molds

AbstractConsumer demand has led to an increase in the use of natural antimicrobials for baked good preservation. In this study, the cell‐free culture supernatants of three antagonistic bacterial strains were tested, and their individual and combined antimicrobial effects on Escherichia coli, Bacillus cereus, Aspergillus neoniger, and Penicillium roqueforti were examined. The mixture of phenyllactic acid and pediocin with ethylenediaminetetraacetic acid (EDTA) exhibited a strong inhibitory effect on E. coli growth (RIA 85%). Nisin mixed with phenyllactic acid or pediocin with EDTA exhibited a strong inhibitory effect on B. cereus growth with RIA 85% and 80%, respectively. Phenyllactic acid had a stronger inhibitory effect on P. roqueforti than on A. neoniger at 50 mg/ml MIC. The antipathogenic effects of phenyllactic acid, nisin, and pediocin (alone or in combination, with or without adjuncts) were stronger than their mold‐controlling effects. A combination of such biopreservatives with EDTA is a suitable alternative to the preservatives used to improve the shelf life of perishable food products.

Dual effect of dietary seaweed of extract nanoparticles (GNS) with bionanocomposite cellulose acetate membranes (CA/bio-AgNps) on growth performance and health status of the Nile tilapia (Oreochromis niloticus): Specification on feed utilization, immune system, and antiparasitic action

Seaweed draws a lot of attention for its vital role in aquaculture as it contains beneficial biological compounds that undoubtedly might help in the development of this field. The current study sheds light on the potential efficiency of dietary supplements of Grateloupia acuminata and G. doryphore (Halymeniaceae) nanoparticles (GNS) at different levels with bionanocomposite cellulose acetate membranes (CA/bio-AgNps) on improved growth performance, digestive enzyme activity, immunity, antioxidative, resistance against infectious pathogens, and characterization of water quality treated with CA/bio-AgNps that is used in rearing Nile tilapia (Oreochromis niloticus). Four concentrations (0.1, 0.25, 0.5, and 1.0 ml/L) of GNS extract were tested as potential anti-bacterial and for the efficacy of being parasitic. Fish with an average weight (24.46 ± 0. 50 g) were apportioned into six experimental groups (T0, T1, T2, T3, T4, and T5) represented as 0.0%, 0.0%, 0.1%, 0.25%, 0.5%, and 1.0% GNS in diets with CA/bio-AgNps, respectively. Injection of fish with Aeromonas hydrophila was performed at the end of the trial. Chemical and bacteriological water indices significantly showed improvement after being treated with CA/bio-AgNps than the control group. Growth, carcass composition, digestive enzyme, and hematological and biochemical indices were significantly noticed positive (p< 0.05), especially T4 and T5, than the control group. In parallel, a significant improvement was noticed in serum lysozyme, total immunoglobulin, complement C3, antioxidative enzyme, and the relative expression of hepatic and inflammatory genes with an increased level of GNS (p< 0.05) are upregulated than the control group. Remarkably, GNS-supplemented diets and extracts provided positive efficacy against A. hydrophila with a decreased percentage of fish mortality, besides efficacy on antibacterial strains and Cichlidogyrus tilapiae, respectively. To sum up, the seaweed extract with CA/bio-AgNps resulted in better growth performance of fish, antipathogenic effect, and health status. Furthermore, CA/bio-AgNps were vital in improving water characteristics. They should be studied and applied more in the future.