Antimicrobial activity of endophytic fungi associated with halophytic species Salsola vermiculata

Endophytic fungi are known for their production of bioactive compounds with antibacterial and antifungal activity. In this study, an evaluation of the antibacterial and antifungal activity of endophytic fungi isolated from Salsola vermiculata, a halophyte species collected from Chott el Hodna, M'sila (Algeria) was carried out. The eleven isolated endophytic fungi were identified as belonging to the genera Alternaria sp., Aureobasidium sp., Phoma sp., Chrysosporium sp., Fusarium sp., Aspergillus sp., Papulaspora sp., Ulocladium sp., Humicola sp. and Pencillium sp. The antimicrobial activity of endophyte isolates was tested against phytopathogenic fungi and pathogenic bacteria using the dual culture and the agar plug diffusion methods respectively. The higher percentage inhibition of 79% was obtained by the isolate Penicillium sp. 1 against Fusarium oxysporum f.sp. ciccri. All isolated endophytic fungi showed antibacterial activity against at least one pathogenic bacterium, the greatest effect was obtained by Fusarium sp. against Pseudomonas aeruginosa ATCC 27853 and Bacillus cereus ATCC 10876 with inhibition zones of 26.33 and 25.33 mm respectively. After the comparison of the means of the zones of inhibition, the isolate Chrysosporium sp. was the most active against all pathogenic bacteria with average inhibition zones of 20.55 mm. DOI: http://dx.doi.org/10.5281/zenodo.703603

Broad antibacterial spectrum of endophytic fungi isolated from halophyte Suaeda fruticosa in Algeria

The purpose of this work was to isolate and evaluate the antimicrobial potential of endophytic fungi isolated from Suaeda fruticosa. Endophytic isolates were identified at the genus level. The genera Fusarium (33.33%), Phoma (26.67%), Penicillium (13.33%), and Aspergillus (13.33%) were more prevalent, while Trichoderma genus (6.67%) was less common. The isolated fungal endophytes were screened for their potential antifungal and antibacterial activities. Most isolates showed different levels of inhibitory activity against at least one of the pathogens. The best inhibition percentages were those obtained by Penicillium sp. 1; 74, 71, 65, and 47% against Fusarium oxysporum f.sp. albedinis, Fusarium oxysporum f.p. ciccri, Fusarium solani var. coeruleum and Phytophthora infestans respectively. Regarding antibacterial activity, the zones of inhibition ranged from 0 to 25.5 mm. Fusarium isolates and Phoma sp. 4 showed the greatest antibacterial activity, the highest activity was observed with Fusarium sp.5 and Fusarium sp. 1, which gave zones of inhibition of 25.5 and 22.5 mm respectively against B. cereus ATCC 10876. Gram-positive bacteria were more sensitive to endophyte isolates than Gram-negative bacteria. From the results of the present work, it is possible to conclude that endophytic fungi isolated from Suaeda fruticosa could be a promising source of bioactive compounds and deserve further study. DOI: http://dx.doi.org/10.5281/zenodo.702827

Metabolic profiling of antimicrobial secondary metabolites produced by Penicillium bilaiae EWB-3 isolated from electronic wastes in Algeria

Penicillium species research has progressed far beyond their ability to produce secondary metabolites with potential biological applications, particularly as antimicrobial agents. In this work, Penicillium bilaiae EWB-3 was isolated from electronic waste and identified using morphological and molecular (ITS and β-tubulin regions) methods. For 15 days, Penicillium bilaiae EWB-3 was grown into Czapek Yeast Broth using an orbital shaker. Finally, the secondary metabolites in this strain’s filtrates were extracted using ethyl acetate. The agar well diffusion method tested this crude extract for antimicrobial activity. The Penicillium bilaiae EWB-3 extract exhibited strong antimicrobial potential against all tested microorganisms, including Pseudomonas aeruginosa, Bacillus cereus, Enterococcus faecalis, Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, Candida albicans and Aspergillus niger. With diameters of 31, 26, and 25 mm, the largest inhibition zones were observed against C. albicans, S. aureus, and E. faecalis, respectively. The presence of 24 active compounds was revealed by gas chromatography-mass spectrometry (GC-MS) analysis of the crude extract of Penicillium bilaiae EWB-3. The findings suggest that the secondary metabolite extract of Penicillium bilaiae EWB-3 could be a promising active pharmaceutical component

Antimicrobial and Antioxidant Activities of Flavonoids Extracted from Pistacia lentiscus L., Leaves

Increasingly, the flavonoids becoming the subject of biomedical researches, and many groups have isolated and identified the structures of flavonoids possessing important biological activities. This assess investigates the antimicrobial fight and the antioxidant strengths of flavonoids extracted from Pistacia lentiscus L. leaves.  The extract was first analyzed for its phenolic content, then the flavonoids were tested for their antimicrobial capacities by the method of diffusion against fourteen bacteria, two fungi and one yeast. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of flavonoids were determined using the dilution method on solid medium, however, the antioxidant activity was evaluated through the ability of the extract to scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals and the reducing power essay. The results indicate that flavonoids extract contain other phenolics groups. On the other side, the Antibacterial tests exhibited different activities depending on the strains. Unlike, the MIC and the MBC showed that the flavonoids extract showed a best activity against Candida albicans and Vibrio cholerae. Concerning antioxidant activity, the results indicate a moderate capacity of the flavonoid extract. These preliminary results may justify the use of this plant in the treatment of some diseases and may be exploited for therapeutic purposes. Keywords: Antimicrobial, Antioxidant, Pistacia lentiscus, flavonoids, MIC, MBC

Dual biocontrol potential of the entomopathogenic fungus Akanthomyces muscarius against Thaumetopoea pityocampa and plant pathogenic fungi

Akanthomyces spp. species are known for their capacity to biocontrol of certain insects and plant pathogens; however, their ability to biocontrol the pine processionary (Thaumetopoea pityocampa) and certain phytopathogenic fungi belonging to the genera Fusarium and Curvularia have not been studied before. In this study, a strain from Akanthomyces muscarius was isolated from wheat grains and then identified by morphological and molecular tests. The strain was further studied for its capacity to control Thaumetopoea pityocampa larvae through dose-mortality tests, and its ability to control some phytopathogenic fungi strains of the genera Fusarium and Curvularia was studied through direct confrontation tests. Dose-mortality tests at three concentrations of Akanthomyces muscarius against the first instar larvae revealed a mortality of 92.15% after 11 days for the concentration of 2.3 × 106 conidia.ml−1, with a median lethal concentration of 7.6 x103 conidia.ml1. Our isolate also showed antifungal activity against these phytopathogenic fungi with inhibition rates ranging from 39.61% to 52.94%. Akanthomyces muscarius proved to be a promising biocontrol agent for plant pests and diseases

Isolation and Screening of Fungal Culture Isolated From Algerian Soil for the Production of Cellulase and Xylanase

Lignocellulolytic enzymes constitute a very large group of extracellular proteins secreting by fungi who is ecologically involved in the degradation of a variety of complex materials, a property that is attributed to a battery of enzymes produced by these microorganisms like cellulases and xylanases who are of significant industrial value and relevance. Forty fungal isolated from rich soil in organic matter were screened for lignocellulolytic enzymes production, its organized on the basis of their hydrolytic potential of cellulose and xylan. The isolates strains presented enzymatic activity which was ranked as follows: cellulolytic (56%), xylanolytic (44%). Some selected strains that produce high levels of enzymes (cellulase, xylanase) grown in submerged fermentation (SmF) and were quantitatively evaluated. The fermentation experiments were carried out in shake flasks. The highest CMCase (5,10 IU/ml) and xylanase (98,25 IU/ml) activities were obtained from Trichoderma sp strain Mtr6 isolate. Keywords: Fungi, Trichoderma sp, lignocellulolytic enzymes, soil, screening, organic matter