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Background Oat ( Avena sativa L.) represents one of the important cereal crops grown in different areas around the world due to its use in human nutrition, food industry, biomaterials, and pharmaceutical industries. Fusarium seedling blight disease (FSBD) represents one of the most dangerous diseases affecting oat cultivation. Endophytic fungi proved to be useful in plant disease management. Therefore, the present study investigated the impact of applied endophytic Trichoderma harzianum AUMC 14897 culture filtrate (CF) on disease severity, plant performance, defense systems, antioxidant activity, and stress-related genes expression in oat plants infected with Fusarium oxysporum . Results The dual culture assay results revealed that T. harzianum is antagonistic against F. oxysporum and could inhibit the growth by 86.6% seven days post inoculation. Scanning electron microscope results showed that the antagonism mechanisms include nutrition, space competition, and mycoparasitism. GC–MS analysis demonstrated the presence of several volatile organic compounds in T. harzianum CF and each component might contribute to its biological activity. In a greenhouse experiment, spraying and irrigation with T. harzianum CF revealed less severe symptoms and slower disease development in the infected oat plants compared to untreated plants. Moreover, T. harzianum CF treatment significantly enhanced the levels of total reducing power, phenolics, flavonoids, chlorophyll, carotenoids, antioxidant enzymes, and stress-related genes expression in F. oxysporum -infected oat plants. Conclusions Our results demonstrated T. harzianum CF has an effective role in controlling FSBD in oat plants as a novel biocontrol agent.

Background A significant threat to the public's health is the rise in antimicrobial resistance among numerous nosocomial bacterial infections. This may be a detriment to present initiatives to enhance the health of immune-compromised patients. Consequently, attention has been devoted to exploring new bioactive compounds in the field of drug discovery from endophytes. Therefore, this study is the first on the production of l -tyrosine (LT) as a promising bio-therapeutic agent from endophytic fungi. Results A new endophytic fungal isolate has been identified for the first time as Rhizopus oryzae AUMC14899 from Opuntia ficus-indica (L.) and submitted to GenBank under the accession number MZ025968. Separation of amino acids in the crude extract of this fungal isolate was carried out, giving a higher content of LT, which is then characterized and purified. LT exhibited strong antibacterial and anti-biofilm activities against multidrug-resistant Gram-negative and Gram-positive bacteria. The recorded minimum inhibitory concentration (MIC) values ranged from 6 to 20 µg/ml. In addition, LT caused a strong reduction in biofilm formation and disrupted the preformed biofilm. Moreover, results indicated that LT supported cell viability, evidencing hemocompatibility and no cytotoxicity. Conclusion Our findings suggest that LT has potential as a therapeutic agent due to its potential antibacterial, anti-biofilm, hemocompatibility, and lack of cytotoxic activities, which may also increase the range of therapy options for skin burn infections, leading to the development of a novel fungal-based drug.

Background Melanin is a natural pigment that is considered a promising biomaterial for numerous biotechnological applications across several industries. Melanin has biomedical applications as antimicrobial, anticancer, and antioxidant properties. Additionally, in the pharmaceutical and cosmetic industries, it is used in drug delivery and as a radioprotective agent. Also, melanin has environmental uses in the fields of bioremediation and the food industry. The biosynthesis of melanin pigment is an area of interest for researchers due to its multifunctionality, high compatibility, and biodegradability. Therefore, our present work is the first attempt to characterize and optimize the productivity of melanin pigment from  Streptomyces djakartensis  NSS-3 concerning its radioprotection and biological properties. Results Forty isolates of soil actinobacteria were isolated from the Wadi Allaqui Biosphere Reserve, Egypt. Only one isolate, ACT3, produced a dark brown melanin pigment extracellularly. This isolate was identified according to phenotypic properties and molecular phylogenetic analysis as  Streptomyces djakartensis  NSS-3 with accession number OP912881. Plackett–Burman experimental design (PBD) and response surface methodology (RSM) using a Box-Behnken design (BBD) were performed for optimum medium and culturing conditions for maximum pigment production, resulting in a 4.19-fold improvement in melanin production (118.73 mg/10 mL). The extracted melanin pigment was purified and characterized as belonging to nitrogen-free pyomelanin based on ultraviolet–visible spectrophotometry (UV–VIS), Fourier transform infrared (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and NMR studies. Purified melanin demonstrated potent scavenging activity with IC 50  values of 18.03 µg/mL and revealed high potency as sunscreens (in vitro SPF = 18.5). Moreover, it showed a nontoxic effect on a normal cell line (WI38), while it had a concentration-dependent anticancer effect on HCT116, HEPG, and MCF7 cell lines with IC 50  = 108.9, 43.83, and 81.99 µg/mL, respectively. Also, purified melanin had a detrimental effect on the tested MDR bacterial strains, of which PA-09 and SA-04 were clearly more susceptible to melanin compared with other strains with MICs of 6.25 and 25 µg/mL, respectively. Conclusion Our results demonstrated that the newly characterized pyomelanin from  Streptomyces djakartensis  NSS-3 has valuable biological properties due to its potential photoprotective, antioxidant, anticancer, antimicrobial, and lack of cytotoxic activities, which open up new prospects for using this natural melanin pigment in various biotechnological applications and avoiding chemical-based drugs.

The use of medicinal plants in marginal communities was for the treatment of various ailments for centuries. Nevertheless, the potential of endophytic fungi (EF) associated with bioprospecting medicinal plants remains understudied. Research on the diversity of EF associated with various Egyptian medicinal plants remains limited. Therefore, our study conducted an analysis and comparison of the colonization frequency (CF), richness, and diversity indices of EF communities that inhabit nine different medicinal plants located in two different areas: the Protected Area of Wadi Degla in Maadi and the Natural Cultivated Area in Helwan, Egypt. These plants were Agathophora alopecuroides , Anabasis setifera , Atriplex halimus , Halocnemum strobitaceum , Lantana camara , Mesembryanthemum forsskaollii , Raphanus raphanistrum , Suaeda vermiculata , and Zygophyllum coccineum . Also, the antimicrobial and antioxidant potential of isolated EF has been investigated. A total of 39 morphospecies EF were isolated and identified, belonging to fifteen genera. Aspergillus spp. and Penicillium spp. were the dominant genera identified in the selected plants. A. setifera and S. vermiculata plants had the highest numbers of EF isolates, followed by M. forsskaollii and R. raphanistrum . Furthermore, these plants had a significant diversity index and species richness compared to other plants investigated. The most predominant EF was Aspergillus sp.3, which had the highest occurrence rate. Among all EF ethyl acetate extracts (EAEs), Aspergillus sp.3 demonstrated the highest antimicrobial activities against different human pathogenic bacteria, yeasts, and fungi. Furthermore, it showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity. Therefore, this isolate was reidentified molecularly as Aspergillus terreus AUMC16223 with accession number PP491988. Moreover, EAE of A. terreus endophyte showed cytotoxicity potential activity with the significant IC 50 value of 41.75 ± 1.83 µg/mL for the human lung carcinoma cell line (A549) and a nontoxic effect on the normal cell line (WI 38) with the significant CC 50 value of 196.2 ± 3.74 µg/mL. Our results indicated diverse EF communities associated with different Egyptian medicinal plants, showing A. terreus endophyte extract as the most significant antimicrobial, antioxidant, and cytotoxic agent.

Background Hazardous synthetic dye wastes have become a growing threat to the environment and public health. Fungal enzymes are eco-friendly, compatible and cost-effective approach for diversity of applications. Therefore, this study aimed to screen, optimize fermentation conditions, and characterize laccase from fungal endophyte with elucidating its ability to decolorize several wastewater dyes. Results A new fungal endophyte capable of laccase-producing was firstly isolated from cladodes of Opuntia ficus - indica and identified as T. harzianum AUMC14897 using ITS-rRNA sequencing analysis. Furthermore, the response surface methodology (RSM) was utilized to optimize several fermentation parameters that increase laccase production. The isolated laccase was purified to 13.79-fold. GFC, SDS-PAGE revealed laccase molecular weight at 72 kDa and zymogram analysis elucidated a single band without any isozymes. The peak activity of the pure laccase was detected at 50 °C, pH 4.5, with thermal stability up to 50 °C and half life span for 4 h even after 24 h retained 30% of its activity. The K m and V max values were 0.1 mM, 22.22 µmol/min and activation energy (E a ) equal to 5.71 kcal/mol. Furthermore, the purified laccase effectively decolorized various synthetic and real wastewater dyes. Conclusion Subsequently, the new endophytic strain produces high laccase activity that possesses a unique characteristic, it could be an appealing candidate for both environmental and industrial applications.

Biofilm formation and hyphal growth are considered to be the most serious virulence factors of Candida species in blood causing candidemia infections, which are difficult to treat due to the spread of resistant Candida isolates to most antifungal drugs. Therefore, in this study, we investigated the effect of different types and concentrations of selected macroalgal extracts from Cladostephus spongiosus (Phaeophyta), Laurencia papillosa (Rhodophyta), and Codium arabicum (Chlorophyta) in inhibiting those virulence factors of the isolated Candida . Acetone extract of C. spongiosus (AECS) showed a stronger anticandidal activity against the selected strains than ethanol extract. Candida krusei was the highest biofilm producer among the selected isolates. AECS showed an inhibition of C. krusei biofilm formation as well as a reduction in the viability of preformed biofilms. Also, AECS reduced various sugars in the candidal exo-polysaccaride layer (EPS). Scanning electron microscopy (SEM) and light microscopic images revealed an absence of hyphae and an alteration in the morphology of biofilm cells when treated with AECS. Moreover, AECS downregulated the expression of hyphal specific genes, hyphal wall protein 1 ( HWP1 ), Agglutinin-like protein 1 ( ALS1 ) and fourth secreted aspartyl proteinase ( SAP4 ), which confirmed the inhibitory effect of AECS on hyphal growth and biofilm formation. Gas chromatography-mass spectrophotometer (GC-MS) analysis of AECS showed three major compounds, which were non-existent in the ethanol extract, and might be responsible for the anticandidal activity; these revealed compounds were 4-hydroxy-4-methyl-2-pentanone, n-hexadecenoic acid, and phenol, 2-methoxy-4-(2-propenyl). These active compounds of AECS may be promising for future pharmaceutical applications in the treatment of candidemia.

L-arginine deiminase (ADI, EC 3.5.3.6) hydrolyzes arginine to ammonia and citrulline which is a natural supplement in health care. ADI was purified from Penicillium chrysogenum using 85% ammonium sulfate, DEAE-cellulose and Sephadex G 200 . ADI was purified 17.2-fold and 4.6% yield with a specific activity of 50 Umg − 1 protein. The molecular weight was 49 kDa. ADI expressed maximum activity at 40 o C and an optimum pH of 6.0. ADI thermostability was investigated and the values of both t 0.5 and D were determined. K d increased by temperature and the Z value was 38 o C. ATP, ADP and AMP activated ADI up to 0.6 mM. Cysteine and dithiothreitol activated ADI up to 60 µmol whereas the activation by thioglycolate and reduced glutathione (GSH) prolonged to 80 µmol. EDTA, α,α-dipyridyl, and o -phenanthroline inactivated ADI indicating that ADI is a metalloenzyme. N-ethylmaleimide (NEM), N-bromosuccinimide (NBS), butanedione (BD), dansyl chloride (DC), diethylpyrocarbonate (DEPC) and N-acetyl-imidazole (NAI) inhibited ADI activity indicating the necessity of sulfhydryl, tryptophanyl, arginyl, lysyl, histidyl and tyrosyl groups, respectively for ADI catalysis. The obtained results show that ADI from P. chrysogenum could be a potential candidate for industrial and biotechnological applications.

Background Biotechnology provides a cost-effective way to produce nanomaterials such as silver oxide nanoparticles (Ag 2 ONPs), which have emerged as versatile entities with diverse applications. This study investigated the ability of endophytic bacteria to biosynthesize Ag 2 ONPs. Results A novel endophytic bacterial strain, Neobacillus niacini AUMC-B524 , was isolated from Lycium shawii Roem. & Schult leaves and used to synthesize Ag 2 ONPS extracellularly. Plackett–Burman design and response surface approach was carried out to optimize the biosynthesis of Ag 2 ONPs (Bio-Ag 2 ONPs). Comprehensive characterization techniques, including UV–vis spectral analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, dynamic light scattering analysis, Raman microscopy, and energy dispersive X-ray analysis, confirmed the precise composition of the Ag 2 ONPS. Bio-Ag 2 ONPs were effective against multidrug-resistant wound pathogens, with minimum inhibitory concentrations (1–25 µg mL −1 ). Notably, Bio-Ag 2 ONPs demonstrated no cytotoxic effects on human skin fibroblasts (HSF) in vitro, while effectively suppressing the proliferation of human epidermoid skin carcinoma (A-431) cells, inducing apoptosis and modulating the key apoptotic genes including Bcl-2 associated X protein ( Bax ), B-cell lymphoma 2 (Bcl-2), Caspase-3 ( Cas-3 ), and guardian of the genome ( P53 ). Conclusions These findings highlight the therapeutic potential of Bio-Ag 2 ONPs synthesized by endophytic N. niacini AUMC-B524, underscoring their antibacterial efficacy, anticancer activity, and biocompatibility, paving the way for novel therapeutic strategies.

The aim of the present work was to immobilize L-arginine deiminase on suitable supports such as chitosan, alginate, and silica gel to study its stability. Additionally, the study aims to investigate the anticancer effects of the free purified enzyme on hepatocellular carcinoma (Hep-G2) and breast cancer (MCF-7) cell lines. L-arginine deiminase (ADI: EC 3.5.3.6) was immobilized on chitosan, Ca-alginate, and silica gel, with immobilization efficiencies of 89.0%, 72.8%, and 66.5%, respectively. The optimal immobilization time for the highest efficiency was 4 h. Increasing the concentration of glutaraldehyde improved the immobilization efficiency of ADI on chitosan. The chitosan-immobilized ADI retained about 45% of its activity after 8 cycles. The optimal pH values were 6 for the free purified ADI and 7 for the chitosan-immobilized ADI. The optimal temperature increased from 40 °C for the free enzyme to 45 °C after immobilization. The activation energies for the free and chitosan-immobilized enzymes were 71.335 kJ/mol and 64.011 kJ/mol, respectively. The K m values for the free and chitosan-immobilized ADI were 0.76 mM and 0.77 mM, respectively, while the V max values were 80.0 U/mg protein for the free ADI and 71.4 U/mg protein for the chitosan-immobilized ADI. After 30 days of storage at 4 °C, the residual activities were 40% for the free purified ADI and 84% for the chitosan-immobilized ADI. At 25 °C, the residual activities were 10% for the free ADI and 75% for the chitosan-immobilized ADI. The chitosan-immobilized ADI exhibited significantly higher stability against proteases such as pepsin and trypsin compared to the free enzyme. The purified ADI also demonstrated enhanced potential anticancer effects and significant cytotoxicity against the Hep-G2 and MCF-7 tumor cell lines compared to doxorubicin. These findings suggest that purified ADI has potential as an anticancer agent, though further in-depth studies are required.

Snail mucus is composed of bioactive compounds thought to have different biological properties for the treatment of some skin problems. Although Helix aspersa mucus is used in several cosmetic products, a detailed characterization of Eremina desertorum mucus composition and its biological activities is still missing. Mucus extracts (MEs) from H. aspersa and E. desertorum were prepared and tested for their antimicrobial and anti-inflammatory activities with their potencies in wound healing. Also, chemical characterization was performed by GC–MS analysis. Results showed that ME of E. desertorum gave higher inhibitory activity against resistant strains related to burn wound infections compared to ME of H. aspersa . Additionally, it revealed a significant anti-inflammatory activity. Moreover, we found that ME of E. desertorum lacked cytotoxicity and was able to significantly induce cell proliferation and migration through up-regulation of TGF-β1 and VEGF gene expression. Our results suggested that MEs of E. desertorum have higher biological effects than H. aspersa, which are attributable to antimicrobial, anti-inflammatory activities, cell proliferation and pave the way for further investigating its potential effect as a human therapeutic agent.