Characterization of Lactobacillus strains isolated from Algerian children faeces for their probiotic properties

Lactic acid bacteria termed probiotics have preventive as well as curative effects on several types of diarrhoea of different aetiologies. The main objective of this study was to screen lactobacilli strains having probiotic traits, isolated from Algerian healthy children faeces on the purpose of using them further in children diarrheal illnesses. One hundred and twenty (120) lactic acid bacteria isolates were selected from faecal samples of healthy Algerian children aged between five and ten years. Gram positive rods and catalase negative bacteria (52 isolates) were screened, in vitro, for their probiotic potential properties including ability to survive in simulated gastro-intestinal conditions, adherence to Caco-2 cells and their antimicrobial activity. The results show that only five strains resisted in simulated gastric juice at pH 1.5 and pepsin. Four of them were resistant to simulated intestinal conditions at pH 8 and pancreatin and have a good adherence. In the end, three of them were retained as they display interesting probiotic profiles characterized by a strong antimicrobial effect against some intestinal pathogenic bacteria. They were identified by 16S rDNA sequencing as Lactobacillus plantarum F12, Lactobacillus brevis G6 and Lactobacillus paracasei B13

Biological activities of essential oils and lipopeptides applied to control plant pests and diseases: a review

Plants are often subject to attack by fungi, nematodes and insects, which generate immense yield losses. Hence, the quest for crop protection solutions is ongoing, concurrent with greater awareness towards the use of synthetic chemicals in agricultural practice. Scientific research has shifted towards the use of natural products, which possess good efficacy and are environment friendly. This review details two classes of natural products. The first one is the plant essential oils with their volatile constituents, which have been proven to possess antifungal, nematicidal and insecticidal activities. The second class is the lipopeptides produced by antagonistic microorganisms. Their biological activities are discussed, as they have been shown effective against plant fungi and pests. Essential oils and lipopeptides have huge potential to be used as biopesticides. The combinatorial approach between essential oils, antagonistic microorganisms and lipopeptides for crop protection is discussed, potentially both can produce a synergistic effect, resulting from their combination against plant fungi, nematodes and pests