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151.
Ortega-Morales BO Chan-Bacab MJ Miranda-Tello E Fardeau ML Carrero JC Stein T 《Journal of industrial microbiology & biotechnology》2008,35(1):9-15
Marine biofilms are a virtually untapped source of bioactive molecules that may find application as novel antifoulants in
the marine paint industry. This study aimed at determining the potential of marine biofilm bacteria to produce novel biomolecules
with potential application as natural antifoulants. Nine representative strains were isolated from a range of surfaces and
were grown in YEB medium and harvested during the late exponential growth phase. Bacterial biomass and spent culture medium
were extracted with ethanol and ethyl acetate, respectively. Extracts were assayed for their antifouling activity using two
tests: (1) antimicrobial well diffusion test against a common fouling bacterium, Halomonas marina, and (2) anti-crustacean activity test using Artemia salina. Our results showed that none of the ethanolic extracts (bacterial biomass) were active in either test. In contrast, most
of the organic extracts had antimicrobial activity (88%) and were toxic towards A. salina (67%). Sequencing of full 16 S ribosomal DNA analysis showed that the isolates were related to Bacillus mojavensis and Bacillus firmus. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) profiling of ethyl acetate extracts
of culture supernatants showed that these species produce the bioactive lipopeptides surfactin A, mycosubtilin and bacillomycin
D. 相似文献
152.
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154.
Gladys Ferrere Anne Leroux Laura Wrzosek Virginie Puchois Fran?oise Gaudin Dragos Ciocan Marie-Laure Renoud Sylvie Naveau Gabriel Perlemuter Anne-Marie Cassard 《PloS one》2016,11(1)
The increase consumption of fructose in diet is associated with liver inflammation. As a specific fructan substrate, fructose may modify the gut microbiota which is involved in obesity-induced liver disease. Here, we aimed to assess whether fructose-induced liver damage was associated with a specific dysbiosis, especially in mice fed a high fat diet (HFD). To this end, four groups of mice were fed with normal and HFD added or not with fructose. Body weight and glucose sensitivity, liver inflammation, dysbiosis and the phenotype of Kupffer cells were determined after 16 weeks of diet. Food intake was increased in the two groups of mice fed with the HFD. Mice fed with HFD and fructose showed a higher infiltration of lymphocytes into the liver and a lower inflammatory profile of Kupffer cells than mice fed with the HFD without fructose. The dysbiosis associated with diets showed that fructose specifically prevented the decrease of Mouse intestinal bacteria in HFD fed mice and increased Erysipelotrichi in mice fed with fructose, independently of the amount of fat. In conclusion, fructose, used as a sweetener, induced a dysbiosis which is different in presence of fat in the diet. Consequently, the activation of Kupffer cells involved in mice model of HFD-induced liver inflammation was not observed in an HFD/fructose combined diet. These data highlight that the complexity of diet composition could highly impact the development of liver lesions during obesity. Specific dysbiosis associated with the diet could explain that the progressions of liver damage are different. 相似文献
155.
Olfa Ben Dhia Thabet Terres Wafa Khelifi Eltaief Jean-Luc Cayol Moktar Hamdi Guy Fauque Marie-Laure Fardeau 《Current microbiology》2011,62(2):486-491
A new moderately halophilic sulfate-reducing bacterium (strain H1T) was enriched and isolated from a wastewater digestor in Tunisia. Cells were curved, motile rods (2–3 x 0.5 μm). Strain H1T grew at temperatures between 22 and 43°C (optimum 35°C), and at pH between 5.0 and 9.2 (optimum 7.3–7.5). Strain H1T required salt for growth (1–45 g of NaCl/l), with an optimum at 20–30 g/l. Sulfate, sulfite, thiosulfate, and elemental sulfur
were used as terminal electron acceptors but not nitrate and nitrite. Strain H1T utilized lactate, pyruvate, succinate, fumarate, ethanol, and hydrogen (in the presence of acetate and CO2) as electron donors in the presence of sulfate as electron acceptor. The main end-products from lactate oxidation were acetate
with H2 and CO2. The G + C content of the genomic DNA was 55%. The predominant fatty acids of strain H1T were C15:0 iso (38.8%), C16:0 (19%), and C14:0 iso 3OH (12.2%), and menaquinone MK-6 was the major respiratory quinone. Phylogenetic analysis of the small-subunit (SSU)
ribosomal RNA (rRNA) gene sequence indicated that strain H1T was affiliated to the genus Desulfovibrio. On the basis of SSU rRNA gene sequence comparisons and physiological characteristics, strain H1T is proposed to be assigned to a novel species of sulfate reducers of the genus Desulfovibrio, Desulfovibrio legallis sp. nov. (= DSM 19129T = CCUG 54389T). 相似文献
156.
Joélle Fournier Marie-Laure Pouénat Martina Rickauer Hélène Rabinovltch-Chable Michel Rigaud Marie-Thérèse Esquerré-Tugayé 《The Plant journal : for cell and molecular biology》1993,3(1):63-70
Lipoxygenase activity was induced in a tobacco cell suspension culture by treatment with glycopeptide elicitors prepared from the cell walls of Phytophthora parasitica var, nicotianae, and in tobacco seedlings infected by this fungal pathogen. Upon purification and characterization, the enzyme appeared to have a molecular weight of 96000, a pl of 5.1 and a Km of 20.9 μM with linoleic acid as substrate. According to its acidic optimum pH, it belongs to type-2 lipoxygenases. Using linoleic, linolenic and arachidonic acids as substrates, the products formed in vitro by lipoxygenase were characterized. 9- and 5-hydroperoxides were the main products obtained from the C18 and C20 fatty acids, respectively, thereby indicating that a 5-lipoxygenase accounts for most of the elicitor-induced activity, since the main site of insertion of molecular oxygen is on C-5 of arachidonic acid. Small amounts of 13-hydroperoxides were also formed from the C18 fatty acids. In vitro, the strongest inhibitors of tobacco lipoxygenase were n-propylgallate and nordihydroguaiaretic acid. The possible involvement of this enzyme in signaling phenomena leading to defense induction in plants via jasmonic acid and other fatty acid-derived products is discussed. 相似文献
157.
ClpP of Bacillus subtilis is required for competence development, motility, degradative enzyme synthesis, growth at high temperature and sporulation 总被引:13,自引:11,他引:2
158.
Hajaij M Carron A Deleuze J Gaven B Setier-Rio ML Vigo G Thiéry I Nielsen-LeRoux C Lagneau C 《Microbial ecology》2005,50(4):475-487
We studied the persistence of Bacillus thuringiensis serovar israelensis (Bti) in a typical breeding site of the mosquito Ochlerotatus caspius in a particularly sensitive salt marsh ecosystem following two Bti-based larvicidal applications (Vectobac 12AS, 1.95 L/ha). The treated area was composed of four larval biotopes that differed in terms of the most representative plant species (Sarcocornia fruticosa, Bolboschoenus maritimus, Phragmites australis, and Juncus maritimus) and the physical and chemical characteristics of the soil. We sampled water, soil, and plants at various times before and after the applications (from spring to autumn, 2001) and quantified the spores of B. thuringiensis (Bt) and Bacillus species. The B. cereus group accounted for between 0% and 20% of all Bacillus spp. before application depending on the larval biotope. No Bti were found before application. The variation in the quantity of bacilli during the mosquito breeding season depended more on the larval biotope than on the season or the larvicidal application. More bacilli were found in soil (10(4)-10(6) spores/g) than on plant samples (10(2)-10(4) spores/g). The abundance in water (10(5) to 10(7) spores/L) appeared to be correlated to the water level of the breeding site. The number of Bti spores increased just after application, after declining; no spores were detected in soil or water 3 months after application. However, low numbers of Bti spores were present on foliage from three of the four studied plant strata. In conclusion, the larvicidal application has very little impact on Bacillus spp. flora after one breeding season (two applications). 相似文献
159.
In Escherichia coli, sigma(E) regulon functions are required for envelope homeostasis during stress and are essential for viability under all growth conditions. The E. coli genome encodes approximately 100 lipoproteins, and 6 of these are regulated by sigma(E). Phenotypes associated with deletion of each of these lipoproteins are the subject of this report. One lipoprotein, YfiO, is essential for cellular viability. However, overexpression of this protein is not sufficient to alleviate the requirement of sigma(E) for viability, suggesting that the sigma(E) regulon provides more than one essential function. The remaining five lipoproteins in the sigma(E) regulon are nonessential; cells are viable even when all five are removed simultaneously. Deletion of three nonessential lipoprotein genes (nlpB, yraP, ygfL) results in the exhibition of phenotypes that suggest they are important for maintenance of the integrity of the cell envelope. deltanlpB cells are selectively sensitive to rifampin; deltayraP cells are selectively sensitive to sodium dodecyl sulfate. Such selective sensitivity has not been previously reported. Both deltayraP and deltanlpB are synthetically lethal with surA::Cm, which encodes a periplasmic chaperone and PPIase, suggesting that NlpB and YraP play roles in a periplasmic folding pathway that functions in parallel with that of SurA. Finally, the deltayfgL mutant exhibits a broad range of envelope defects, including sensitivity to several membrane-impermeable agents, an altered outer membrane protein profile, synthetic lethality with both surA::Cm and deltafkpA::Cm strains, and sensitivity to a bactericidal permeability-increasing peptide. We suggest that this lipoprotein performs a very important but as-yet-unknown function in maintaining the integrity of the cell envelope. 相似文献
160.
The cell interactions that specify the spatial pattern of vulval precursor cell (VPC) fates differ between the nematodes Oscheius tipulae CEW1 and Caenorhabditis elegans. In the former, the centered pattern of fates is obtained by two successive inductions from the gonadal anchor cell, whereas in the latter, a single inductive step by the anchor cell (EGF-Ras-MAP kinase pathway) can act as a morphogen and is reinforced by lateral signaling between the vulval precursors (Notch pathway). We performed a genetic screen for vulva mutants in O. tipulae CEW1. Here we present the mutants that specifically affect the vulval induction mechanisms. Phenotypic and epistatic analyses of these mutants show that both vulval induction steps share common components, one of which appears to be MEK kinase(s). Moreover, the inductive pathway (including MEK kinase) influences the competence of the vulval precursor cells and more strikingly their division pattern as well, irrespective of their vulval fate. Finally, a comparison of vulval mutant phenotypes obtained in C. elegans and O. tipulae CEW1 highlights the evolution of vulval induction mechanisms between the two species. 相似文献