17 research outputs found

    Antioxidant properties, antimicrobial and anti-adhesive acivities of DCS1 lipopeptides from Bacillus methylotrophicus DCS1

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    Background: The present work aims to investigate the antioxidant and antimicrobial activities as well as the potential of DCS1 lipopeptides produced by Bacillus methylotrophicus DCS1 strain at inhibition and disruption of biofilm formation. Results: The produced biosurfactants were characterized as lipopeptides molecules by using thin layer chromatography (TLC) and Fourier transform infrared spectroscopy (FT-IR). The DCS1 lipopeptides were assayed for their antioxidant activity through five different tests. The scavenging effect on DPPH radicals at a concentration of 1 mg mL−1 was 80.6%. The reducing power reached a maximum value of 3.0 (OD700 nm) at 2 mg mL−1 . Moreover, the DCS1 lipopeptides exhibited a strong inhibition of ÎČ-carotene bleaching by linoleic acid assay with 80.8% at 1 mg mL−1 and showed good chelating ability and lipid peroxidation inhibition. The in vitro antimicrobial activity of DCS1 lipopeptides showed that they display significant antibacterial and antifungal activities. The anti-adhesive activity of DCS1 lipopeptides was evaluated against several pathogenic microorganisms. The lipopeptides showed excellent anti-adhesive activity, even at low concentrations, in a polystyrene surface pre-treatment against all the microorganisms tested. Further, they can disrupt performed biofilms. Conclusion: This study shows the potentiality of DCS1 lipopeptides as natural antioxidants, antimicrobial and/or anti-adhesive agent for several biomedical and industrial applications

    Structural characterization and identification of cyclic lipopeptides produced by Bacillus methylotrophicus DCS1 strain

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    Bacillus methylotrophicus DCS1 strain was isolated from diesel contaminated soil and screened for its ability to produce biosurfactants; it was found effective for the production of surface active molecules. The structural characterization of the isolated lipopeptides was studied by a variety of analytical techniques. The organic extract of DCS1 'lipopeptides was fractionated by silica gel column chromatography (60 Mesh). Fractions containing lipopeptides were collected and identified by tandem mass spectrometry MALDI-TOF-MS and MALDI-TOF MS2. The crude biosurfactants contains a mixture of homologous lipopeptides with molecular weights between 1016 and 1556 Da. Mass spectrometry analysis of partially purified lipopeptides revealed that it contains different isoforms belonging to three families: surfactin, iturin and fengycin. To identify lipopeptides isoforms, MALDI-TOF MS2 was used and ions representing characteristic fragmentations were detected. The mass spectrometry characterization revealed the presence of four variants of surfactin lipopeptides, four variants of pumilacidin that differ according to the-beta-hydroxy fatty acid chain length as well as the type of amino acid at position 7, five variants of iturin A/mycosubtilin varying in the beta-amino fatty acid chain length from C12 to C16, C16 iturin Cl, five isoforms of bacillomycin D varying in the beta-amino fatty acid chain length from C14 to C18, and six fengycin isoforms that differ according to the length of the beta-hydroxy fatty acid side chain as well as the amino acid at position 6. The capacity of B. methylotrohicus DCS1 strain to produce many lipopeptides isoforms belonging to different families and having a structural diversity is a very interesting characteristic that allows them to be used in various fields of biotechnological applications

    Enhanced accumulation of root hydrogen peroxide is associated with reduced antioxidant enzymes under isoosmotic NaCl and Na2SO4 salinities

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    The inhibitory effect of salt stress on lettuce is one of the main reasons for the reduction of plant growth and crop productivity. In the present study, the response of two lettuce varieties Verte and Romaine to isoosmotic NaCl and Na2SO4 treatments were examined. Both varieties were grown in pots containing nutrient Hoagland solution with or without 100 mM NaCl or 77 mM Na2SO4. Relative growth rate (RGR), hydraulic parameters, root ion content, proline and several antioxidant activities in roots were measured after 12 days of treatment. After prolonged exposure to salt stress, relative growth rate and water content of lettuce significantly decreased. Roots accumulated high level of Na+ under both salts, whereas the accumulation of K+ and Ca2+ decreased. High level of Na+ inside the cells inhibited the K+ uptake and resulted in increased K+/Na+ ratio. In addition, salt stress also caused an increase in the accumulation of proline. This result suggests that proline may play a crucial role in protecting lettuce under salt stress especially in response to Na2SO4 treatment. Membrane damage estimated by electrolyte leakage (EL) increased especially in response to Na2SO4 treatment in both varieties, but Verte had significantly lower EL relative to Romaine under 100 mM NaCl. A reduction in the activities of CAT in both varieties under 100 mM, and GPX activity in Verte under Na2SO4 treatment coincided with an increase in H2O2 level, indicative of cellular damage and a general depression of the antioxidant enzymatic system in lettuce roots.Keywords: Lettuce, NaCl, Na2SO4, RGR, mineral nutrition, antioxidant activities, prolin

    Combined effect of hormonal priming and salt treatments on germination percentage and antioxidant activities in lettuce seedlings

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    Hormonal priming is a pre-sowing treatment that improves seed germination performance and stress tolerance. To understand the physiology of hormonal priming and its association with post priming stress tolerance, we investigated the effect of hormonal priming with increasing gibberellic acid (GA3) concentrations (0, 3, 4.5 and 6 mM) on seedling growth and antioxidant system in lettuce. Germination percentage was higher in lettuce seedlings derived from primed seeds. Radicle and hypocotyl length and dry weight were reduced by salt treatment to a greater extent in non-primed than in primed seeds. Hormonal priming with 4.5 mM GA3 induced the most dramatic decreases in electrolyte leakage (EL) and malondialdehyde (MDA) levels. NaCl increased catalase (CAT) activity in primed and non-primed seeds. The total ascorbate level remained constant in both primed and non-primed seeds under NaCl constraint. These results suggest that hormonal priming might have increased the salt tolerance of lettuce seeds through enhancing the activities of antioxidant enzymes and reducing the membrane damage as estimated using EL and MDA biomarkers.Key words: Ascorbate, germination, hormonal priming, lettuce, salinity

    Les lipopeptides de Bacillus: des molécules bioactives à structure particuliÚre et à forte potentialité d'application [Bacillus lipopeptides : bioactives molecules with particular structure and high application potential]

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    Since the end of the 20th century, the efforts regarding the environment protection have been increasingly intensified. As most of surfactants used at present arise from the chemical industry, the search for new biological surfactants or biosurfactants of microbial origin with lesser side effects is of great interest. Neutral lipids, glycolipids, phospholipids, lipopolysaccharides and lipopeptides are listed among biosurfactants. Lipopeptides synthetized by microorganisms, in particular those of the genus Bacillus, are the most promising, because of their excellent interfacial properties and their biological activities. Surfactines, fengycines and iturines are the main families of biosurfactants produced by the genus through a ribosome-independent mechanism. Considering their potentialities and their harmlessness, lipopeptides have been used in various fields such as environment petroleum industry and agronomy. The application of lipopeptides in the foodprocessing and pharmaceutical industries should be improved. This review is a synthesis of the knowledge acquired, until now, on the biosurfactants produced by the genus Bacillus. We have focused on the structure of lipopeptides, their mode of synthesis as well as their biological activities and their potential applications

    Antioxidant properties, antimicrobial and anti-adhesive activities of DCS1 lipopeptides from Bacillus methylotrophicus DCS1

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    Abstract Background The present work aims to investigate the antioxidant and antimicrobial activities as well as the potential of DCS1 lipopeptides produced by Bacillus methylotrophicus DCS1 strain at inhibition and disruption of biofilm formation. Results The produced biosurfactants were characterized as lipopeptides molecules by using thin layer chromatography (TLC) and Fourier transform infrared spectroscopy (FT-IR). The DCS1 lipopeptides were assayed for their antioxidant activity through five different tests. The scavenging effect on DPPH radicals at a concentration of 1 mg mL−1 was 80.6%. The reducing power reached a maximum value of 3.0 (OD700 nm) at 2 mg mL−1. Moreover, the DCS1 lipopeptides exhibited a strong inhibition of ÎČ-carotene bleaching by linoleic acid assay with 80.8% at 1 mg mL−1 and showed good chelating ability and lipid peroxidation inhibition. The in vitro antimicrobial activity of DCS1 lipopeptides showed that they display significant antibacterial and antifungal activities. The anti-adhesive activity of DCS1 lipopeptides was evaluated against several pathogenic microorganisms. The lipopeptides showed excellent anti-adhesive activity, even at low concentrations, in a polystyrene surface pre-treatment against all the microorganisms tested. Further, they can disrupt performed biofilms. Conclusion This study shows the potentiality of DCS1 lipopeptides as natural antioxidants, antimicrobial and/or anti-adhesive agent for several biomedical and industrial applications

    Production and Biochemical Characterization of a High Maltotetraose (G4) Producing Amylase from Pseudomonas stutzeri AS22

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    Amylase production and biochemical characterization of the crude enzyme preparation from Pseudomonas stutzeri AS22 were evaluated. The highest -amylase production was achieved after 24 hours of incubation in a culture medium containing 10 g/L potato starch and 5 g/L yeast extract, with initial pH 8.0 at 30 ∘ C under continuous agitation at 200 rpm. The optimum temperature and pH for the crude -amylase activity were 60 ∘ C and 8.0, respectively. The effect of different salts was evaluated and it was found that both -amylase production and activity were Ca 2+ -dependent. The amylolytic preparation was found to catalyze exceptionally the formation of very high levels of maltotetraose from starch (98%, w/w) in the complete absence of glucose since the initial stages of starch hydrolysis (15 min) and hence would have a potential application in the manufacturing of maltotetraose syrups

    Antioxidant properties, antimicrobial and anti-adhesive acivities of DCS1 lipopeptides from Bacillus methylotrophicus DCS1

    No full text
    Background: The present work aims to investigate the antioxidant and antimicrobial activities as well as the potential of DCS1 lipopeptides produced by Bacillus methylotrophicus DCS1 strain at inhibition and disruption of biofilm formation. Results: The produced biosurfactants were characterized as lipopeptides molecules by using thin layer chromatography (TLC) and Fourier transform infrared spectroscopy (FT-IR). The DCS1 lipopeptides were assayed for their antioxidant activity through five different tests. The scavenging effect on DPPH radicals at a concentration of 1 mg mL−1 was 80.6%. The reducing power reached a maximum value of 3.0 (OD700 nm) at 2 mg mL−1 . Moreover, the DCS1 lipopeptides exhibited a strong inhibition of ÎČ-carotene bleaching by linoleic acid assay with 80.8% at 1 mg mL−1 and showed good chelating ability and lipid peroxidation inhibition. The in vitro antimicrobial activity of DCS1 lipopeptides showed that they display significant antibacterial and antifungal activities. The anti-adhesive activity of DCS1 lipopeptides was evaluated against several pathogenic microorganisms. The lipopeptides showed excellent anti-adhesive activity, even at low concentrations, in a polystyrene surface pre-treatment against all the microorganisms tested. Further, they can disrupt performed biofilms. Conclusion: This study shows the potentiality of DCS1 lipopeptides as natural antioxidants, antimicrobial and/or anti-adhesive agent for several biomedical and industrial applications
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