The Influence of Lactobacillus spp. Secondary Metabolites Isolated from Immature Egyptian Honey on Human Pathogens, Transcription of Virulence Genes and Lung Cancer.

This work aimed to isolate, and identify Lactic Acid Bacteria LAB from Egyptian immature citrus honey, and characterize their secondary metabolites, as well as determine the antibacterial activities and transcription of virulence genes (stx1, stx2, and eae) influenced by these bacterial secondary metabolites. From twenty hives, twenty immature citrus bee honey samples were taken. Traditional cultural and biochemical testing were used, followed by molecular confirmation. Further, LAB isolates' antibacterial and cytotoxic properties were investigated. 16S rRNA gene sequencing were assessed and, two lactic acid bacterial isolates were identified as Lactobacillus acidophilus Ch2 and Levilactobacillus brevis Ch1. Both isolates have good antagonistic action against clinical pathogens, with Levilactobacillus brevis Ch1 exhibiting the best antibacterial activity against all indicator pathogens examined. When compared to untreated cancer cells, the isolates demonstrated significant cytotoxic activity. Ch1 and Ch2 cell viability percentages were 39.5% and 18.76%, respectively. Furthermore, when exposed to Levilactobacillus brevis Ch1 metabolites, Shiga-producing Escherichia coli (STEC) virulence gene expression was suppressed. To identify bacterial secondary metabolites, a high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOF) approach was developed. Twenty-seven metabolites from diverse chemical classes were discovered in the crude extracts with antibacterial and anticancer characteristics. This is the first thorough investigation on the metabolic profile of LAB isolated from immature Egyptian honey and the findings suggested that isolates or their secondary metabolites could be used in the food sector as medicinal alternatives or as a biocontrol agent.

Point-of-care ultrasound to diagnose acute cholecystitis in the emergency department: A scoping review.

Introduction/Purpose: Ultrasound is the first-line imaging modality for suspected acute cholecystitis. This can be radiology-performed ultrasound or point-of-care ultrasound (POCUS). POCUS can potentially streamline patient assessment in the emergency department (ED). The primary objective was to evaluate the literature for the diagnostic accuracy of POCUS performed for acute cholecystitis in the ED. Secondary objectives were to assess the effect of POCUS operator training on diagnostic accuracy for acute cholecystitis, utility of POCUS measurement of the common bile duct and POCUS impact on resource utilisation. Methods: A systematic scoping review of articles was conducted using Medline, Embase, CENTRAL and CINAHL. Original studies of adults with POCUS performed for the diagnosis of acute cholecystitis in the ED were included. The study was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist (PRISMA-ScR). Results: A total of 1090 publications were identified. Forty-six met the eligibility criteria. Studies were thematically grouped into categories according to specified objectives. Point-of-care ultrasound was of acceptable but variable accuracy, contributed to by the absence of a consistent reference standard and uniform training requirements. It may positively impact ED resource utilisation through reduced ED length of stay and radiology-performed imaging, whilst improving patient experience. Conclusion: This review highlights the heterogeneity of existing research, emphasising the need for standardisation of training and reference standards in order to precisely define the utility of POCUS for acute cholecystitis in the ED and its benefits on ED resource utilisation.

Optimization of Chitosan-Decorated Solid Lipid Nanoparticles for Improved Flurbiprofen Transdermal Delivery.

Transdermal delivery is a potential alternative route to oral administration for drugs associated with stomach discomfort, such as flurbiprofen, a widely nonsteroidal anti-inflammatory drug (NSAID). This study aimed to design solid lipid nanoparticle (SLN) transdermal formulations of flurbiprofen. Chitosan-coated SLNs were prepared by the solvent emulsification method, and their properties and permeation profiles across the excised rat skin were characterized. The particle size of uncoated SLNs was at 695 ± 4.65 nm, which increased to 714 ± 6.13, 847 ± 5.38, and 900 ± 8.65 nm upon coating with 0.05, 0.10, and 0.20% of chitosan, respectively. The drug association efficiency was improved when a higher concentration of chitosan was employed over SLN droplets that endowed a higher affinity of flurbiprofen with chitosan. The drug release was significantly retarded as compared to the uncoated entities and followed non-Fickian anomalous diffusion that was depicted by "n" values of >0.5 and <1. Also, the total permeation of chitosan-coated SLNs (F7-F9) was significantly higher than that of the noncoated formulation (F5). Overall, this study has successfully designed a suitable carrier system of chitosan-coated SLNs that provide insight into the current conventional therapeutic approaches and suggest new directions for the advancements in transdermal drug delivery systems for improved permeation of flurbiprofen.

Identification of Antimicrobial Metabolites from the Egyptian Soil-Derived Amycolatopsis keratiniphila Revealed by Untargeted Metabolomics and Molecular Docking.

Actinomycetes are prolific producers of bioactive secondary metabolites. The prevalence of multidrug-resistant (MDR) pathogens has prompted us to search for potential natural antimicrobial agents. Herein, we report the isolation of rare actinobacteria from Egyptian soil. The strain was identified as Amycolatopsis keratiniphila DPA04 using 16S rRNA gene sequencing. Cultivation profiling, followed by chemical and antimicrobial evaluation of crude extracts, revealed the activity of DPA04 ISP-2 and M1 culture extracts against Gram-positive bacteria. Minimum inhibitory concentrations (MIC) values ranged from 19.5 to 39 µg/mL. Chemical analysis of the crude extracts using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF) led to the identification of 45 metabolites of different chemical classes. In addition, ECO-0501 was identified in the cultures with significant antimicrobial activity. Multidrug resistance in Staphylococcus aureus is reported to be related to the multidrug efflux pump (MATE). ECO-0501 and its related metabolites were subjected to molecular docking studies against the MATE receptor as a proposed mechanism of action. ECO-0501 and its derivatives (AK_1 and N-demethyl ECO-0501) had better binding scores (-12.93, -12.24, and -11.92 kcal/mol) than the co-crystallized 4HY inhibitor (-8.99 kcal/mol) making them promising candidates as MATE inhibitors. Finally, our work established that natural products from this strain could be useful therapeutic tools for controlling infectious diseases.

Synthesis and Characterization of Sulfur Nanoparticles of Citrus limon Extract Embedded in Nanohydrogel Formulation: In Vitro and In Vivo Studies.

The study aimed to synthesize non-noxious, clean, reliable, and green sulfur nanoparticles (SNPs) from Citrus limon leaves. The synthesized SNPs were used to analyze particle size, zeta potential, UV-visible spectroscopy, SEM, and ATR-FTIR. The prepared SNPs exhibited a globule size of 55.32 ± 2.15 nm, PDI value of 0.365 ± 0.06, and zeta potential of -12.32 ± 0.23 mV. The presence of SNPs was confirmed by UV-visible spectroscopy in the range of 290 nm. The SEM image showed that the particles were spherical with a size of 40 nm. The ATR-FTIR study showed no interaction, and all the major peaks were preserved in the formulations. An antimicrobial and antifungal study of SNPs was carried out against Gram-positive bacteria (Staph. aureus, Bacillus), Gram-negative bacteria (E. coli and Bordetella), and fungal strains (Candida albicans). The study showed that Citrus limon extract SNPs exhibited better antimicrobial and antifungal activities against Staph. aureus, Bacillus, E. coli, Bordetella, and Candida albicans at a minimal inhibitory concentration of 50 µg/mL. Different antibiotics were used alone and in combination with SNPs of Citrus limon extract to evaluate their activity against various strains of bacteria and fungal strains. The study showed that using SNPs of Citrus limon extract with antibiotics has a synergistic effect against Staph.aureus, Bacillus, E. coli, Bordetella, and Candida albicans. SNPs were embedded in nanohydrogel formulations for in vivo (wound healing) studies. In preclinical studies, SNPs of Citrus limon extract embedded within a nanohydrogel formulation (NHGF4) have shown promising results. To be widely used in clinical settings, further studies are needed to evaluate their safety and efficacy in human volunteers.

Cholinesterase Inhibitors from an Endophytic Fungus Aspergillus niveus Fv-er401: Metabolomics, Isolation and Molecular Docking.

Alzheimer's disease poses a global health concern with unmet demand requiring creative approaches to discover new medications. In this study, we investigated the chemical composition and the anticholinesterase activity of Aspergillus niveus Fv-er401 isolated from Foeniculum vulgare (Apiaceae) roots. Fifty-eight metabolites were identified using UHPLC-MS/MS analysis of the crude extract. The fungal extract showed acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory effects with IC50 53.44 ± 1.57 and 48.46 ± 0.41 µg/mL, respectively. Two known metabolites were isolated, terrequinone A and citrinin, showing moderate AChE and BuChE inhibitory activity using the Ellman's method (IC50 = 11.10 ± 0.38 µg/mL and 5.06 ± 0.15 µg/mL, respectively for AChE, and IC50 15.63 ± 1.27 µg/mL and 8.02 ± 0.08 µg/mL, respectively for BuChE). As evidenced by molecular docking, the isolated compounds and other structurally related metabolites identified by molecular networking had the required structural features for AChE and BuChE inhibition. Where varioxiranol G (-9.76 and -10.36 kcal/mol), penicitrinol B (-9.50 and -8.02 kcal/mol), dicitrinol A (-8.53 and -7.98 kcal/mol) and asterriquinone CT5 (-8.02 and -8.25 kcal/mol) showed better binding scores as AChE and BuChE inhibitors than the co-crystallized inhibitor (between -7.89 and 7.82 kcal/mol) making them promising candidates for the development of new drugs to treat Alzheimer's.

Genome-Based Analysis of the Potential Bioactivity of the Terrestrial Streptomyces vinaceusdrappus Strain AC-40.

Streptomyces are factories of antimicrobial secondary metabolites. We isolated a Streptomyces species associated with the Pelargonium graveolens rhizosphere. Its total metabolic extract exhibited potent antibacterial and antifungal properties against all the tested pathogenic microbes. Whole genome sequencing and genome analyses were performed to take a look at its main characteristics and to reconstruct the metabolic pathways that can be associated with biotechnologically useful traits. AntiSMASH was used to identify the secondary metabolite gene clusters. In addition, we searched for known genes associated with plant growth-promoting characteristics. Finally, a comparative and pan-genome analysis with three closely related genomes was conducted. It was identified as Streptomyces vinaceusdrappus strain AC-40. Genome mining indicated the presence of several secondary metabolite gene clusters. Some of them are identical or homologs to gene clusters of known metabolites with antimicrobial, antioxidant, and other bioactivities. It also showed the presence of several genes related to plant growth promotion traits. The comparative genome analysis indicated that at least five of these gene clusters are highly conserved through rochei group genomes. The genotypic and phenotypic characteristics of S. vinaceusdrappus strain AC-40 indicate that it is a promising source of beneficial secondary metabolites with pharmaceutical and biotechnological applications.

Formulation and Characterization of Ethyl Cellulose-Based Patches Containing Curcumin-Chitosan Nanoparticles for the Possible Management of Inflammation via Skin Delivery.

Curcumin, a natural phenolic compound, exhibits poor absorption and extensive first pass metabolism after oral administration. In the present study, curcumin-chitosan nanoparticles (cur-cs-np) were prepared and incorporated into ethyl cellulose patches for the management of inflammation via skin delivery. Ionic gelation method was used for the preparation of nanoparticles. The prepared nanoparticles were evaluated for size, zetapotential, surface morphology, drug content, and % encapsulation efficiency. The nanoparticles were then incorporated into ethyl cellulose-based patches using solvent evaporation technique. ATR-FTIR was used to study/assess incompatibility between drug and excipients. The prepared patches were evaluated physiochemically. The in vitro release, ex vivo permeation, and skin drug retention studies were carried out using Franz diffusion cells and rat skin as permeable membrane. The prepared nanoparticles were spherical, with particle size in the range of 203-229 nm, zetapotential 25-36 mV, and PDI 0.27-0.29 Mw/Mn. The drug content and %EE were 53% and 59%. Nanoparticles incorporated patches are smooth, flexible, and homogenous. The in vitro release and ex vivo permeation of curcumin from nanoparticles were higher than the patches, whereas the skin retention of curcumin was significantly higher in case of patches. The developed patches deliver cur-cs-np into the skin, where nanoparticles interact with skin negative charges and hence result in higher and prolonged retention in the skin. The higher concentration of drug in the skin helps in better management of inflammation. This was shown by anti-inflammatory activity. The inflammation (volume of paw) was significantly reduced when using patches as compared to nanoparticles. It was concluded that the incorporation of cur-cs-np into ethyl cellulose-based patches results in controlled release and hence enhanced anti-inflammatory activity.

Immunogenicity and effectiveness of a bivalent influenza A/H1N2 vaccine strain against seasonal human influenza A viruses in mice.

BACKGROUND: Recent studies and reports have documented the ability of the co-circulating seasonal influenza A/H1N1 (ancestor: 2009 pandemic H1N1) and A/H3N2 to exchange their genetic segments, generating a novel H1N2 strain in different geographical localities around the world with an ability to infect human. This raises concerns and triggers alarms to develop a multivalent vaccine that can protect against the documented H1- and H3-type human influenza A viruses (IAVs). RESULTS: Here, we generated a PR8-based vaccine strain that carries the HA gene segment from the contemporary H1N1 virus while the NA gene segment was derived from a currently circulating influenza A/H3N2 strain. A recombinant PR8-based H1N2 vaccine strain (rgH1N2), engineered by reassortment between influenza A/H1N1 and A/H3N2 to mimic the documented human influenza A/H1N2, was used for immunization to provoke immunogenicity and cross-antigenicity against the H1- and H3-type human IAVs and was evaluated for its immunogenicity and effectiveness in mice. Following challenge infection of rgH1N2-vaccinated mice with contemporary influenza A/H1N1 and A/H3N2, results revealed that rgH1N2-vaccinated mice showed less viral shedding, more survival, and less body weight loss compared to control unvaccinated groups and vaccinated mice with rgH1N1 and rgH3N2. CONCLUSIONS: This study highlights the applicability of the PR8-based H1N2 vaccine strain to protect against seasonal IAVs and emphasizes the role of both surface proteins, HA and NA, to stimulate protective and neutralizing antibodies against circulating influenza A/H1N1 and A/H3N2 strains.

Emergency medicine trainees' perceived barriers to training and credentialing in point-of-care ultrasound: A cross-sectional study.

Introduction: Point-of-care ultrasound (POCUS) is an important tool in emergency medicine (EM), with the Australasian College for Emergency Medicine (ACEM) recommending core modalities as part of fellowship training. In Australia, acquisition of these skills is certified via credentialing but is currently poorly undertaken by EM trainees. Methods: We performed a cross-sectional survey of EM trainees across two academic teaching hospitals in Gold Coast, Queensland, between December 2018 and January 2019, to determine the current state of training and perceived barriers to credentialing in POCUS. Results: Fifty-two (59%) eligible EM trainees participated. Although credentialing rates (15%) were low amongst respondents, the majority agreed that it was necessary (69%) and should form part of ACEM training (88%). Amongst these trainees, we identified the desire for increased POCUS training and several barriers including time constraints and the credentialing process itself. Conclusion: Although there is general agreement amongst EM trainees for POCUS credentialing, barriers such as time limitations and technical difficulties were prohibitive for many. We propose the development of an internal structured POCUS training programme within mandatory training time to address these issues.

Evaluating the Phenotypic and Genomic Characterization of Some Egyptian Phages Infecting Shiga Toxin-Producing Escherichia coli O157:H7 for the Prospective Application in Food Bio-Preservation.

Shiga toxin-producing E. coli (STEC) is considered a worldwide public health and food safety problem. Despite the implementation of various different approaches to control food safety, outbreaks persist. The aim of study is to evaluate the applicability of phages, isolated against STEC O157:H7, as prospective food bio-preservatives. Considering the relatively wide host range and greatest protein diversity, two phages (STEC P2 and P4) from four were furtherly characterized. Complete genome analysis confirmed the absence of toxins and virulence factors-encoding genes. The results confirmed the close relation of STEC P2 to phages of Myoviridae, and STEC P4 to the Podoviridae family. The phages retained higher lytic competence of 90.4 and 92.68% for STEC P2 and P4, respectively with the HTST pasteurization. The strong acidic (pH 1) and alkaline (pH 13) conditions had influential effect on the surviving counts of the two phages. The lowest survivability of 63.37 and 86.36% in STEC P2 and P4 lysate, respectively appeared in 2% bile salt solution after 3 h. The results confirmed the strong effect of simulated gastric fluid (SGF) on the survivability of the two phages comparing with simulated intestinal fluid (SIF). Therefore, the two phages could be applied as a natural alternative for food preservation.

COVID-19 infection and thyroid function.

Context: COVID-19 is a new viral infection affecting mainly the respiratory system with involvement of many other organs. Thyroid dysfunction has been described in COVID-19 but data are still unclear and conflicting on its frequency, severity and relationship with the outcome. Patients and methods: We assessed thyroid function tests (TFT) in 50 patients admitted to our institution with confirmed COVID-19 infection. We excluded patients known to have thyroid diseases or taking drugs that may affect thyroid function. Serum free thyroxine (FT4), thyrotropin (TSH) and triiodothyronine (T3) were measured once or more during the first 10 days after admission. In about 50 % of the cases, a follow up TFT was obtained during the first year after discharge (at a median follow up of 6 months). Results: We included 50 patients, 29 males (58 %) and 21 females (42 %). The median age was 47 years (range 25-89). Overall, TFTs were completely normal in all patients except for minor transient abnormalities in 5 patients (10 %) as follows: three patients had a mild transient elevated TSH, one had a mild transient suppressed TSH and one patient had a mildly low FT4 with normal TSH. There were no differences between the follow up TFTs obtained after discharge and TFTs obtained during admission in the acute phase. Conclusion: In this study, thyroid dysfunction during acute COVID-19 infection was rare, mild and transient. However, the study might not be powered enough to detect an association between thyroid dysfunction and the severity of illness and further studies are needed to assess this issue. Late-onset thyroid dysfunction does not seem to occur in COVID-19 infection during the next year after discharge.

Infectious Pepper Mild Mottle Virus and Human Adenoviruses as Viral Indices in Sewage and Water Samples.

The objective of this study was to compare human adenoviruses (HAdVs) genome and infectivity, polyomaviruses (JC and BK) genome (JCPyVs) and (BKPyVs), Pepper Mild Mottle Virus (PMMoV) genome and infectivity, and infectious bacteriophages as viral indices for sewage and water samples. One hundred and forty-four samples were collected from inlets and outlets of water and wastewater treatment plants (WTPs), and WWTPs within Greater Cairo from October 2015 till March 2017. Two methods of viral concentration [Aluminium hydroxide (Al(OH)3) precipitation method and adsorption-elution technique followed by organic flocculation method] were compared to determine which of them was the best method to concentrate viruses from sewage and water. Although samples with only one litre volume were concentrated using Al(OH)3 precipitation method and the same samples with larger volumes (5-20 L) were concentrated using the adsorption-elution technique followed by the organic flocculation method, a non-significant difference was observed between the efficiency of the two methods in all types of samples except for the drinking water samples. Based on the qualitative prevalence of studied viruses in water and wastewater samples, the number of genome copies and infectious units in the same samples, resistance to treatment processes in water and wastewater treatment plants, higher frequency of both adenoviruses and PMMoV genomes as candidate viral indices in treated sewage and drinking water was observed. The problem of having a viral genome as indices of viral pollution is that it does not express the recent viral pollution because of the longer survivability of the viral genome than the infectious units in water and wastewater. Both infectious adenovirus and infectious phiX174 bacteriophage virus showed similar efficiencies as indices for viral pollution in drinking water and treated sewage samples. On the other hand, qualitative detection of infectious PMMoV failed to express efficiently the presence/absence of infectious enteric viruses in drinking water samples. Infectious adenoviruses and infectious bacteriophage phiX174 virus may be better candidates than adenoviruses genome, polyomaviruses genome, and PMMoV genome and infectivity as viral indices for water and wastewater.

Incidence and neutralizing antibody seroprevalence of influenza B virus in Egypt: Results of a community-based cohort study.

Since 2000, two lineages of influenza B viruses, Victoria and Yamagata, have been circulating at similar frequencies worldwide. Little is known about the circulation of those viruses in Egypt. This study aims to describe the epidemiology of influenza B virus infections in Egypt, 2017-2019. This was performed through a household prospective cohort study on influenza infections among 2400 individuals from five villages. When a study participant had influenza like symptoms, a nasal swab and an oropharyngeal swab were obtained and tested by RT-PCR for influenza B infections. A serum sample was obtained from all participants annually to detect neutralizing antibodies using microneutralization assay. 9.1% of subjects were positive for influenza B viruses during season 2017-2018 mostly among preschoolers and 7.6% were positive during the season 2018-2019 with higher risk in females, potentially due to mothers being infected after contact with their children. The overall seroprevalence among the participants was 53.2% and 52.2% against the Victoria and Yamagata lineages respectively, the majority of seropositive participants were students. Multivariate analysis showed that age and having chronic diseases were the strongest predictors of infection. Our results show that both influenza B lineages circulated between 2017 and 2020 in Egypt almost in equal proportion. Encouraging the uptake of seasonal influenza vaccines is recommended.

Evaluation of different bacterial honey isolates as probiotics and their efficient roles in cholesterol reduction.

Continue to hypothesize that honey is a storehouse of beneficial bacteria, and the majority of these isolates are levansucrase producers. Accordingly, ten bacterial strains were isolated from different honey sources. Four honey isolates that had the highest levansucrase production and levan yield were identified by the partial sequencing of the 16S rRNA gene as Achromobacter sp. (10A), Bacillus paralicheniformis (2M), Bacillus subtilis (9A), and Bacillus paranthracis (13M). The cytotoxicity of the selected isolates showed negative blood hemolysis. Also, they are sensitive to the tested antibiotics (Amoxicillin + Flucloxacillin, Ampicillin, Gentamicin, Benzathine benzylpenicillin, Epicephin, Vancomycin, Amikacin, and Zinol). The isolates had strong alkaline stability (pHs 9, 11) and were resistant to severe acidic conditions (29-100 percent). The tested isolates recorded complete tolerance to both H2O2 and the bile salt (0.3% Oxgall powder) after 24 h incubation. The cell-free supernatant of the examined strains had antifungal activities against C. Albicans with varying degrees. Also, isolates 2M and 13M showed strong activities against S. aureus. The isolates showed strong adhesion and auto-aggregation capacity. Isolate 10A showed the highest antioxidant activity (91.45%) followed by 2M (47.37%). The isolates recorded different catalase and protease activity. All isolates produced cholesterol oxidase and lipase with different levels. Besides, the four isolates reduced LDL (low-density lipoprotein) to different significant values. The cholesterol-reducing ability varied not only for strains but also for the time of incubation. The previous results recommended these isolates be used safely in solving the LDL problem.

Molecular characterization of endophytic and ectophytic plant growth promoting bacteria isolated from tomato plants (Solanum lycopersicum L.) grown in different soil types.

BACKGROUND: Successful rhizosphere colonization by plant growth promoting rhizobacteria (PGPR) is of crucial importance to perform the desired plant growth promoting activities. Since rhizocompetence is a dynamic process influenced by surrounding environmental conditions. In the present study, we hypothesized that bacterial isolates obtained from different tomato plant microhabitats (balk soil, rhizosphere, endorhiza, phyllosphere, and endoshoot) grown in different soils (sand, clay, and peat moss) will show different rhizocompetence abilities. RESULTS: To evaluate this hypothesis, bacterial isolates were obtained from different plant microhabitats and screened for their phosphate solubilizing and nitrogen fixing activates. BOX-PCR fingerprint profiles showed high genotypic diversity among the tested isolates and that same genotypes were shared between different soils and/or plant microhabitats. 16S rRNA gene sequences of 25 PGP isolates, representing different plant spheres and soil types, were affiliated to eight genera: Enterobacter, Paraburkholderia, Klebsiella, Bacillus, Paenibacillus, Stenotrophomonas, Pseudomonas, and Kosakonia. The rhizocompetence of each isolate was evaluated in the rhizosphere of tomato plants grown on a mixture of the three soils. Different genotypes of the same bacterial species displayed different rhizocompetence potentials. However, isolates obtained from the above-ground parts of the plant showed high rhizocompetence. In addition, biological control-related genes, ituD and srfC, were detected in the obtained spore forming bacterial isolates. CONCLUSION: This study evaluates, for the first time, the relationship between plant microhabitat and the rhizocompetence ability in tomato rhizosphere. The results indicated that soil type and plant sphere can influence both the genotypic diversity and rhizocompetence ability of the same bacterial species. Bacterial isolates obtained in this study are promising to be used as an environmentally friendly substitution of chemical fertilizers.

Simultaneous determination of ofloxacin and bromfenac in combined dosage form using four different spectrophotometric methods.

Four simple, precise, accurate and validated spectrophotometric methods have been developed for the simultaneous determination of ofloxacin (OFL) and bromfenac sodium (BROM). Firstly, first and second derivative spectrophotometric methods (1D &2D) using a zero-crossing technique utilizing 309.3 and 257.5 nm for OFL and 290.7 and 246.5 nm for BROM as optimum working wavelengths in a binary mixture, respectively. Secondly, the first derivative ratio spectrophotometric method (1DD) in which peak amplitudes at 297.3 nm and 260.7 nm were chosen to simultaneously estimate OFL and BROM, respectively. Thirdly, dual wavelength (DW) method based on two selected wavelengths for each drug in such a way that the difference in absorbance is zero for the second one. At wavelengths 296.4, 348.4 nm BROM has equal absorbance values, therefore, these two wavelengths have been used to determine OFL. Similarly, 271.7 nm and 313.1 nm were selected to determine BROM in the combined formulation. Finally, the fourth method depends on ratio difference spectrophotometry (RDSM), in which the difference between amplitudes at 305.6 nm and 326.5 nm on the ratio spectrum of the mixture was directly proportional to the concentration of OFL; independent of the interfering components. Similarly, the difference between amplitudes at 265.1 nm and 275.4 nm on the ratio spectrum was used for the determination of BROM. The linearity was confirmed in the range of 4 - 18 µg/ml for OFL and BROM for the four methods. The proposed methods were used to determine both drugs in their laboratory prepared mixture and combined formulation with mean percentage recoveries of 99.41 ± 1.35% for OFL and 99.98 ± 1.30 % for BROM in method (A). In method (B), the mean percentage recoveries were 101.70 ± 1.61% for OFL and 101.90 ± 1.45% for BROM. In method (C) OFL was 99.57 ± 1.61% and 100.90 ± 1.62% for BROM. Finally, in method (D) the mean percentage recoveries were 99.37 ± 1.67% for OFL and 100.70 ± 1.59% for BROM. The developed methods were successfully employed for determination of OFL and BROM in laboratory prepared mixtures and combined formulation showing satisfactory recoveries. Methods validation was performed according to the International Conference on Harmonization (ICH) guidelines. The obtained results conformed to the accepted ranges of recovery, precision and repeatability.

Biosynthesis and Characterization of Silver Nanoparticles Produced by Phormidium ambiguum and Desertifilum tharense Cyanobacteria.

The world faces a challenge with the pervasion of multidrug-resistant bacteria that encourages scientists to develop and discover alternative, ecofriendly, and easy-to-produce new antibacterial agents. Our work is part of the greater effort of scientists around the world to achieve this goal by the biological synthesis of silver nanoparticles using cyanobacterial extracellular and intracellular components as nonchemical reducing agents. Two Egyptian cyanobacteria were isolated and identified according to 16S rRNA gene sequencing as Phormidium ambiguum and a novel species Desertifilum tharense. The sequences were deposited with accession numbers MW762709 and MW762710 for Desertifilum tharense and Phormidium ambiguum, respectively, in the GenBank. The results of UV-Vis analysis showed promising extracellular Ag-NPs synthesis by Desertifilum tharense and Phormidium ambiguum under light conditions. Therefore, these Ag-NPs were characterized and evaluated for antibacterial and antioxidant activity. TEM and SEM analyses revealed the spherical crystals with face-centered cubic structures and size range of 6.24-11.4 nm and 6.46-12.2 nm for Ag-NPs of Desertifilum tharense and Phormidium ambiguum, respectively. XRD and EDX results confirmed the successful synthesis of Ag-NPs in their oxide form or chloride form. The FTIR spectrum data confirmed the presence of hydroxyl and amide groups. Desertifilum tharense Ag-NPs displayed the largest inhibition zone that ranged from 9 mm against Micrococcus luteus ATCC 10240 to 25 mm against methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300. For Phormidium ambiguum Ag-NPs, the inhibition zone diameter was in the range of 9 mm to 18 mm. The biosynthesized Ag-NPs significantly inhibited the growth of medically important resistance-pathogenic Gram-positive and Gram-negative bacteria. The Ag-NPs of Phormidium ambiguum exhibited the highest scavenging activity of 48.7% when compared with that of Desertifilum tharense, which displayed 43.753%.

Isolation, identification, and application of lactic acid-producing bacteria using salted cheese whey substrate and immobilized cells technology.

BACKGROUND: Lactic acid bacteria (LAB) could be used for bio-production of lactic acid (LA) from wastes of dairy industries. This study aimed to produce LA using isolated and identified LAB capable of withstanding high salt concentration of salted cheese whey and adopting immobilization technique in repeated batch fermentation process. RESULTS: Seventy four isolates of LAB were isolated from salted cheese whey and examined for lactic acid production. The superior isolates were biochemically and molecularly identified as Enterococcus faecalis, Enterococcus faecium, and Enterococcus hirae. Then the best of them, Enterococcus faecalis, Enterococcus hirae and dual of them besides Lacticaseibacillus casei were immobilized by sodium alginate 2% in entrapped cells. Repeated batch fermentation was executed for LA production from the mixture of salted whey and whey permeate (1:1) using immobilized strains during static state fermentation under optimum conditions (4% inoculum size in mixture contained 5% sucrose and 0.5% calcium carbonate and incubation at 37 °C). The potent bacterial strain was Enterococcus faecalis which gave the maximum LA production of 36.95 g/l with a yield of 81% after 36 h incubation at 37 °C in presence of 5% sugar. CONCLUSION: Immobilized cells exhibited good mechanical strength during repetitive fermentations and could be used in repetitive batch cultures for more than 126 days.

Molecular identification and in vitro evaluation of probiotic functional properties of some Egyptian lactic acid bacteria and yeasts.

BACKGROUND: The health-promoting effects along with global economic importance of consuming food products supplemented with probiotic microorganisms encouraged the researchers to discover new probiotics. RESULTS: Fourteen lactic acid bacterial isolates were identified as Enterococcus mediterraneensis, Lactobacillus fermentum, and Streptococcus lutetiensis by 16S rRNA gene sequencing, and in vitro characterized for their actual probiotic potential. All E. mediterraneensis isolates were resistant to clindamycin, whereas Lb. fermentum isolates were resistant to ampicillin, clindamycin, and vancomycin. The E. mediterraneensis and Lb. fermentum isolates displayed high overall digestive survival, ranged from 1.35 ± 0.06 to 32.73 ± 0.84% and from 2.01 ± 0.01 to 23.9 ± 1.85%, respectively. All isolates displayed cell surface hydrophobicity, ranged between 15.44 ± 6.72 and 39.79 ± 2.87%. The strongest auto-aggregation capability, higher than 40%, was observed for most E. mediterraneensis and Lb. fermentum isolates. The E. mediterraneensis isolates (L2, L12, and L15), Lb. fermentum (L8, L9, and L10), and Strep. lutetiensis (L14) exhibited the greatest co-aggregation with Salmonella typhimurium, Escherichia coli O157:H7, Staphylococcus aureus, and Bacillus cereus. Fifty-seven and fourteen hundredth percent of E. mediterraneensis isolates could be considered bacteriocinogenic against E. coli O157:H7, B. cereus, and S. aureus. CONCLUSION: This study is the first one to isolate Enterococcus mediterraneensis in Egypt and to characterize it as new species of probiotics globally. According to the results, E. mediterraneensis (L2, L12, and L15), Lb. fermentum (L8, L9, and L10), and Strep. lutetiensis (L14) are the most promising in vitro probiotic candidates.