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Abstract Biosynthesis silver nanoparticles (AgNPs) have received a lot of attention as a cytotoxic and antimicrobial activity against pathogenic bacteria. This study was carried out to evaluate the potential ability of red marine algae Corallina elongata and Gelidium amansii to biosynthesis AgNPs capping with Sodium Dodecyl Sulfate (SDS) and to determine its antibacterial efficacy. Characterization of capping AgNPs were determined by Ultra violet-Visible spectroscopy, Transmission electron microscope (TEM), Scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDX), Zeta potential and sizer. The results indicated that there is no variation change between capping AgNPs synthesis by two red algae in plasmon resonance peak and also both stable along 3 weeks. The capping nanoparticles size were range from 8 to 25 nm in the case of G. amansii and 12–20 nm C. elongata. The results were obtained from Fourier transforms infrared spectroscopy (FTIR) indicated that same metals are present in both algae except Vanadium (V) was present with G. amansii. Capping AgNPs biosynthesis by C. elongata had more toxicity to Chlorella vulgaris than that of synthesized by G. amansii. Capping AgNPs by SDS have been shown to enhance antibacterial activity against Micrococcus leutus , Kocuria varians and Escherichia coli ATCC 8739 compared to non-capping AgNPs. The antibacterial activity and toxicity of AgNPs is affected by concentrations of capping agent and the biomaterial (red algae) that used for synthesis. Highlights • Biosynthesis of AgNPs using Corallina elongata and Gelidium amansii and capping by SDS possess different characterization, cytotoxic activity against Chlorella vulgaris and also differ effects against pathogenic bacteria. • Biosynthesis AgNPs and capping by SDS had more efficiency against pathogenic bacteria. • The best concentrations of SDS in case of AgNPs synthesis by C. elongate was 6 mM whereas G. amansii was 9 mM. [ABSTRACT FROM AUTHOR]

Background: Plant disease administration is difficult due to the soil-borne nature of the phytopathogens. Biological control of plant disease is a safe mode to avoid the problems related to fungal diseases that affect crops productivity. Results: Twenty-three Trichoderma isolates were isolated from soil, surrounding healthy tomato roots from different regions in the Egyptian Governorate of Menoufia. Using a dual culture method to test the efficiency of Trichoderma isolates, the most effective isolate identified as Trichoderma atrovirde with percentage inhibition against Fusarium oxysporum f. sp. lycopersici (92.11%) and scanning electron microscope examination documented the mycoparasitic nature of T. atrovirde to F. oxysporum. Treatments with 10% filtrate T. atrovirde improved the growth aspects of tomato plants than the control plants or infected only, as well as the increase in phenol content (15.09 ug. g-1dry weight) and decreased disease incidence percentage (8%) than the plants infected only (60%). Conclusions: This study clearly demonstrated that T. atrovirde had a significant inhibition against F. oxysporum. Greenhouse assays displayed the protective role of T. atrovirde inoculation directly against pathogen or indirectly related to the defense mechanism in the plant. So, this study recommends using T. atrovirde for biological control of wilt disease in tomato plants. [ABSTRACT FROM AUTHOR]