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1.
Characterization of Bacillus and Pseudomonas strains with suppressive traits isolated from tomato hydroponic-slow filtration unit 总被引:1,自引:0,他引:1
Renault D Déniel F Benizri E Sohier D Barbier G Rey P 《Canadian journal of microbiology》2007,53(6):784-797
Bacillus and Pseudomonas spp. are known to be involved in plant pathogenic fungi elimination during the slow filtration process used in tomato soilless cultures. We isolated 6-8 strains of both Bacillus and Pseudomonas from the top, middle, and bottom sections of filters and identified them after 16S rDNA sequencing. Four Pseudomonas strains were identified as Pseudomonas fulva, 5 as Pseudomonas plecoglossicida, and 12 as Pseudomonas putida. The use of specific oligonucleotide polymerase chain reaction primer sets designed from gyrB gene sequences additionally permitted the identification of 17 Bacillus cereus and 3 Bacillus thuringiensis strains. Ribotyping with EcoRI pointed out an important polymorphism within Bacillus and Pseudomonas strains. Molecular characterization did not reveal a correlation between the location of isolates within the filter (top, middle, or bottom) and bacterial identification or riboclusters. Functional aspects assessed by community-level physiological profiling showed marked phenotypic differences between Pseudomonas communities isolated from the top and bottom filter layers; differences were lower between Bacillus communities of different layers and far less noticeable between mixed communities of Bacillus and Pseudomonas. These strains were tested for several suppressive activities. Conversely to most Bacillus, the majority of Pseudomonas strains were auxin producers and promoted the growth of tomato plantlet roots. On the other hand, only Bacillus strains displayed antagonistic activities by inhibiting the growth of pathogenic fungi frequently detected in soilless cultures. Siderophores were produced by nearly all bacteria, but at higher amounts by Pseudomonas than Bacillus strains. The biocontrol agent potentiality of certain strains to optimize the slow filtration process and to promote the suppressive potential of nutrient solution is discussed. 相似文献
2.
Le Floch Gaétan Rey Patrice Benizri Emile Benhamou Nicole Tirilly Yves 《Plant and Soil》2003,257(2):459-470
Plant growth promotion induced by the antagonistic fungus, Pythium oligandrum, is the result of a complex interaction which includes an indirect effect through control of pathogens in the rhizosphere and/or a direct one mediated by plant-induced resistance. The present study shows an increased plant growth associated with direct interaction between P. oligandrum and roots, which is mediated by a fungus-produced auxin compound, tryptamine (TNH2). In vitro experiments provided evidence that P. oligandrum metabolised specifically indole derivatives, such as tryptophan and indole-3-acetaldehyde, to produce THN2 through the tryptamine pathway. When P. oligandrum grew in sterile root exudates, it also produced an auxin-like compound. Additional experiments on P. oligandrum–root interaction showed that, in amended nutrient solution of plants, the antagonist metabolised Trp into TNH2 and that root absorption of this newly formed auxin-compound in appropriate concentrations was associated with enhancement of plant growth. This phenomenon was observed only when nutrient solution was amended with low tryptophan (Trp) concentrations, i.e. 0.05 and 0.1 mM; higher concentration (0.5 and 1 mM Trp) induced abnormal root development. Similar experiments were performed with Pythium group F, a minor pathogen known for its ability to produce auxin-compounds through the tryptamine pathway. In this case, irregular root development was always noticed with all Trp concentrations added to the nutrient solution of plants. Moreover, Pythium group F colonization of roots was associated with leakage of auxin-compounds in the nutrient solution. Our results, therefore, highlight that the production of similar auxin-compounds by two Pythium species has contrary effects on plant development. 相似文献
3.
Mickael Cregut Severine Piutti Sophie Slezack-Deschaumes Emile Benizri 《Microbiological research》2013,168(1):12-21
Arylsulfatases allow microorganisms to satisfy their sulfur (S) requirements as inorganic sulfate after sulfate ester hydrolysis. Our objectives were to investigate the arylsulfatase activities among soil isolates, especially Streptomyces sp., Microbacterium sp. and Rhodococcus sp., because such investigations are limited for these bacteria, which often live in sulfate-limited conditions. Physiological and biochemical analyses indicated that these isolates possessed strong specific arylsulfatase activities ranging from 6 to 8 U. Moreover, for Streptomyces sp., an arylsulfatase localization study revealed 2 forms of arylsulfatases. A first form was located in the membrane, and a second form was located in the intracellular compartment. Both arylsulfatases had different patterns of induction. Indeed, the intracellular arylsulfatase was strictly induced by inorganic sulfate limitation, whereas the membrane arylsulfatase was induced both by substrate presence or S demand independently. For Microbacterium and Rhodococcus isolates, only a membrane arylsulfatase was found. Consequently, our results suggest the presence of a previously undescribed arylsulfatase in these microorganisms that allows them to develop an alternative strategy to fulfill their S requirements compared to bacteria previously studied in the literature. 相似文献
4.
E Yefenof R Benizri Y Reiter E Klein Z Fishelson 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(4):1538-1543
The interaction of two Burkitt lymphoma lines, Raji and Rael, with human C and NK cells was analyzed. Raji cells activate the alternative C pathway (ACP) and then bind C3 fragments. Consequently, the cells become more sensitive to lysis by CR3-bearing NK cells but not to C lysis. In contrast, Rael cells are poor ACP activators, do not bind C3 fragments, and are therefore resistant to C-dependent NK lysis. As suggested earlier, the difference between Raji and Rael could be attributed to the presence or absence of CR2, respectively, on their surface. To potentiate C- and NK-dependent lysis of target cells, we generated heteroconjugates composed of a murine antitransferrin receptor mAb and of human C C3b or iC3b. Antibody-C3b conjugates induced C3 deposition on Rael cells and elevated C3 deposition on Raji cells in human serum. Both Raji and Rael cells coated with antibody-C3b conjugates were efficiently lyzed by the cytolytic ACP in human serum. This conjugate had a small enhancing effect on target cell lysis by NK cells which could be markedly increased by combined treatment of the target cell with antibody-C3b conjugate and C5-depleted human serum. On the other hand, antibody-iC3b conjugates efficiently potentiated lysis of target cells by NK cells in the absence of serum. The iC3b-directed cytotoxicity was mediated by CR3-bearing NK effector cells. Anti-C3 but not anti-mouse Ig antibodies abrogated the activity of the antibody-iC3b conjugate. These results further demonstrate that NK cytotoxicity may be potentiated by opsonizing the target cells with C3 fragments and suggest that antibody-C3b/iC3b conjugates could be potent tools for targeting and potentiation of the lytic action of both C and NK cells against tumor cells. 相似文献
5.
Danila Caruso Manon Meyrel Karoline Krane-Gartiser Victoire Benard Chloé Benizri Héléna Brochard 《Chronobiology international》2020,37(1):101-110
ABSTRACTEveningness and sleep disturbances are considered as markers of Bipolar Disorder (BD) and influence mood and emotional or behavioral states. This study investigates the associations between circadian markers and sleep quality on residual depressive symptoms and inhibition/activation dimensions during the euthymic phase. A sample of 89 euthymic adult individuals with BD was assessed for circadian preference and typology using the Composite Scale of Morningness (CSM) and the Circadian Type Inventory (CTI) and for sleep quality using the Pittsburgh Sleep Quality Index (PSQI). The Montgomery and Asberg Depression Rating Scale (MADRS) and the Multidimensional Assessment of Thymic States (MAThyS) were used to measure residual depressive symptoms and the inhibition/activation dimensions. We examined any associations between these parameters using correlations and path analyses. We identified significant associations between eveningness and poorer sleep quality that correlated to higher depressive residual symptoms and a global inhibition. The use of path analyses led us to conclude that poor sleep quality mediated the relationship between eveningness and either residual mood symptoms or behavioral inhibition (motivation, sensory perception, interpersonal interaction, and cognition). These factors should be considered in the clinical evaluation of individuals with BD, with a specific attention during the euthymic phase, in order to achieve the best functional outcome possible. 相似文献
6.
Durand Alexis Sterckeman Thibault Gonnelli Cristina Coppi Andrea Bacci Giovanni Leglize Pierre Benizri Emile 《Plant and Soil》2021,461(1-2):203-218
Plant and Soil - Non-mycorrhizal species such as Banksia (Proteaceae) that depend on root exudates to acquire phosphorus (P) are prominent in south-western Australia, a biodiversity hotspot on... 相似文献
7.
C Prunas K Krane-Gartiser C Nevoret V Benard C Benizri H Brochard 《Chronobiology international》2013,30(8):1124-1130
ABSTRACTChildhood attention-deficit hyperactivity disorder (ADHD) is a common precursor of adult bipolar disorders (BD). Furthermore, actigraphy studies demonstrate that each disorder may be associated with abnormalities in sleep and activity patterns. This study investigates whether the presence or absence of self-reported childhood experiences of ADHD symptoms is associated with different sleep and activity patterns in adults with BD. A sample of 115 euthymic adult patients with BD was assessed for childhood ADHD symptoms using the Wender Utah Rating Scale (WURS) and then completed 21 days of actigraphy monitoring. Actigraphic measures of sleep quantity and variability and daytime activity were compared between BD groups classified as ADHD+ (n = 24) or ADHD? (n = 91), defined according to established cutoff scores for the WURS; then we examined any associations between sleep–wake cycle parameters and ADHD dimensions (using the continuous score on the WURS). Neither approach revealed any statistically significant associations between actigraphy parameters and childhood ADHD categories or dimensions. We conclude that the sleep and activity patterns of adult patients with BD do not differ according to their self-reported history of ADHD symptoms. We discuss the implications of these findings and suggest how future studies might confirm or refute our findings. 相似文献
8.
Phuy-Chhoy Vong Séverine Piutti Emile Benizri Sophie Slezack-Deschaumes Christophe Robin Armand Guckert 《Plant and Soil》2007,294(1-2):19-29
Investigating the impact of plant species on sulphur (S) availability in the rhizosphere soil is agronomically important to
optimize S fertilization. Bulk, rhizosphere soils and the roots of field-grown rape and barley were sampled 7 times (every
fortnight), from March to June, at plant maturity. Root carbon (C) and nitrogen (N) in water extract, along with soil SO42−-S, labile soil organic-C (HWC) and -N (HWN) in hot water extract, as well as soil arylsulphatase activity were then monitored.
The average concentrations of both HWC and HWN were observed in the following decreasing order: rape rhizosphere soil >barley
rhizosphere soil >bulk soil. In parallel, the average contents of water extractable-C and -N in rape roots were higher than
those in barley roots. These results suggest that soil C and N contents in hot water extract (including rhizodeposition) were
correlated with C and N released by roots. Great ARS activities found in rape rhizosphere soil were accompanied by great SO42−-S mineralization over time. Finally, bulk and rhizosphere soils of rape and barley were pooled from the seven samplings and
incubated with the corresponding pooled root water-soluble C of both plant species and glucose-C. After 1 and 9 weeks, a greater
net S mineralization (gross mineralization - immobilization) was observed with rape root water-soluble C than with barley
root water-soluble C and glucose-C. Conjointly, we found a higher average value of ARS activity in rape rhizosphere than in
barley rhizosphere soil. Our findings suggest that plant species, via their rhizodeposition, determine the dynamic of S in
soil. 相似文献
9.
Maize root colonization by two fluorescent
Pseudomonas strains M.3.1. and TR335, isolated respectively from
maize and tomato roots, were studied in hydroponic conditions. Each bacterium
was inoculated separately, and three different colonization areas were
studied: nutrient solution, rhizoplane, and endorhizosphere. The two
Pseudomonas strains established large rhizosphere populations, and
rhizoplane colonization of the entire root system was similar for both
strains. However, strain M.3.1. colonized the endorhizosphere more
efficiently than strain TR335. Seminal root cuttings from the tip to the seed
allowed the assessment of colonization of three different root areas (i.e.,
root cap and elongation area, root-hair zone, and mature zone). Rhizoplane
colonizations of all these three areas by M.3.1. were significantly the same,
whereas strain TR335 colonized the rhizoplane of the root cap and elongation
area more actively than the root-hair zone and mature zone. Population size
of the strain M.3.1. in the internal tissue of these areas was greater than
that of strain TR335. Co-inoculations of the two strains indicated a
stimulation of the population size of strain M.3.1. regardless of root area
studied, whereas population size of strain TR335 remained unchanged. These
results demonstrated that external and internal maize root tissues were
colonized to a greater extent by a strain isolated from a maize rhizosphere
than by one isolated from another rhizosphere.
Received: 26 September 1996 / Accepted: 1 November 1996 相似文献
10.
Ramez Farajallah Saad Ahmad Kobaissi Gaylord Machinet Geneviève Villemin Guillaume Echevarria Emile Benizri 《Ecological Research》2018,33(4):799-810
Nickel (Ni) agromining aims to phytoextract heavy metals using hyperaccumulators whilst at the same time rehabilitating ultramafic soils. After removing the bioavailable metal, ultramafic soils are improved in terms of their agronomic properties with the aim of future agricultural uses. The low fertility of ultramafic soils can be compensated by integrating legumes already used in traditional agro-systems because of their importance in soil nitrogen enrichment. However, few studies have evaluated the potential profits of legumes on Ni agromining and their potential benefits on soil biological fertility. Here, we characterized the effect of a crop rotation with two plants, a legume (Vicia sativa) and a hyperaccumulator (Alyssum murale), on the phytoextraction efficiency and on soil structure and biofunctioning. A pot experiment was set up in controlled conditions to grow A. murale and four treatments were tested: rotation with V. sativa (Ro), fertilized mono-culture (FMo), non-fertilized mono-culture (NFMo) and bare soil without plants (BS). No significant difference was found between the Ro and NFMo treatments for the dry biomass yield. However, the Ro treatment showed the highest Ni concentrations ([Ni]) in A. murale shoots compared to FMo and NFMo treatments. The Ro treatment plants had more than twice as many leaves [Ni] compared to FMo. Soil physico-chemical analyses showed that the Ro treatment was better structured and showed the highest presence of bacterial micro-aggregates, as well as less non-aggregated particles. Legumes integration in Ni-agromining systems could be a pioneering strategy to reduce chemical inputs and to improve soil biofunctioning and thus fertility. 相似文献