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

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

Resistance of Telluric Fungi to Chemical Fungicides

Our work focuses on the identification of resistance of telluric fungi to commonly used fungicidesin chemical control. We investigate the resistance of telluric fungi (Fusarium sp., Chalara sp., Sporonema sp., Stiebum sp., Didymabotrium sp., Dothichiza sp. and Sclerotopsis sp.) from cereal fields to four fungicides (Propicone, Vapcotop, Curitine V and Kazir). This study was based on direct contact of the telluric isolates with fungicides on Petri dishes. For the four tested fungicides different rates of resistance and susceptibility were observed according to the isolate and the used concentration. One of the isolates showed a high resistance to Vapcotop with 500 mg%252Fl. Generally the statistical analysis revealed that there are no significant differences in the effect of fungicides concentrations against isolates, while significant differences are observed between isolates

Screening of Antimicrobial and Antioxidant Secondary Metabolites from Endophytic Fungi Isolated from Wheat (Triticum Durum)

Abstract: The emergence of antibiotic-resistant micro-organisms calls for inventive research and development strategies. Inhibition of these pathogenic micro-organisms may be a promising therapeutic approach. The screening of antimicrobial compounds from endophytes is a promising way to meet the increasing threat of drug-resistant strains of human and plant pathogens. In the present study, a total of 20 endophytic fungi and 23 endophytic actinomycetes have been isolated from wheat (Triticum durum). Mohamed Ben Bachir variety collected from Bordj Bou Arreridj region (Algeria) during winter 2010. The isolates were screened and evaluated for their antimicrobial and antioxidant activities. Antimicrobial activity was evaluated for crude ethyl acetate extracts using an agar dif-fusion assay against twelve pathogenic bacteria, yeast, and two phytopathogenic fungi. All extracts showed inhibitory activity on at least one or more pathogenic microorganisms, with an average zone of inhibition varied between 7 mm to 25 mm, and the largest zone was of 25 and 25.3 mm against candida albicans and Escherichia coli respectively. The antioxidant capacity of the extracts was evalu-ated by β-carotene/linoleic acid assay. Results showed that 60 % of these extracts have antioxidant activity, exhibiting 50, 57 % to 78, 96 % inhibitions. While the inhibitory activity for oxidation of linoleic acid of 40 % of them was less than 50%. From the present work it is possible to conclude that these microorganisms could be promising source of bioactive compounds, and warrant further study. Key words: endophytic microorganisms, antimicrobial activity, antioxidant activity, Triticum duru