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61.
62.
Lulwoana sp., a dark septate endophyte in roots of Posidonia oceanica (L.) Delile seagrass
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L. Torta S. Lo Piccolo G. Piazza S. Burruano P. Colombo D. Ottonello R. Perrone G. Di Maida M. Pirrotta A. Tomasello S. Calvo 《Plant biology (Stuttgart, Germany)》2015,17(2):505-511
Posidonia oceanica is the most common, widespread and important monocotyledon seagrass in the Mediterranean Basin, and hosts a large biodiversity of species, including microorganisms with key roles in the marine environment. In this study, we ascertain the presence of a fungal endophyte in the roots of P. oceanica growing on different substrata (rock, sand and matte) in two Sicilian marine meadows. Staining techniques on root fragments and sections, in combination with microscope observations, were used to visualise the fungal presence and determine the percentage of fungal colonisation (FC) in this tissue. In root fragments, statistical analysis of the FC showed a higher mean in roots anchored on rock than on matte and sand. In root sections, an inter‐ and intracellular septate mycelium, producing intracellular microsclerotia, was detected from the rhizodermis to the vascular cylinder. Using isolation techniques, we obtained, from both sampling sites, sterile, slow‐growing fungal colonies, dark in colour, with septate mycelium, belonging to the dark septate endophytes (DSEs). DNA sequencing of the internal transcribed spacer (ITS) region identified these colonies as Lulwoana sp. To our knowledge, this is the first report of Lulwoana sp. as DSE in roots of P. oceanica. Moreover, the highest fungal colonisation, detected in P. oceanica roots growing on rock, suggests that the presence of the DSE may help the host in several ways, particularly in capturing mineral nutrients through lytic activity. 相似文献
63.
Stinchfield MJ Takaesu NT Quijano JC Castillo AM Tiusanen N Shimmi O Enzo E Dupont S Piccolo S Newfeld SJ 《Development (Cambridge, England)》2012,139(15):2721-2729
The ability of secreted Transforming Growth Factor β (TGFβ) proteins to act as morphogens dictates that their influence be strictly regulated. Here, we report that maternally contributed fat facets (faf; a homolog of USP9X/FAM) is essential for proper interpretation of the zygotic Decapentaplegic (Dpp) morphogen gradient that patterns the embryonic dorsal-ventral axis. The data suggest that the loss of faf reduces the activity of Medea (a homolog of Smad4) below the minimum necessary for adequate Dpp signaling and that this is likely due to excessive ubiquitylation on a specific lysine. This study supports the hypothesis that the control of cellular responsiveness to TGFβ signals at the level of Smad4 ubiquitylation is a conserved mechanism required for proper implementation of a morphogen gradient. 相似文献
64.
Esther Imperlini Carmelina Bianco Enza Lonardo Serena Camerini Michele Cermola Giancarlo Moschetti Roberto Defez 《Applied microbiology and biotechnology》2009,83(4):727-738
We evaluated the effects of the main auxin phytohormone, indole-3-acetic acid (IAA), on the central metabolism of Sinorhizobium meliloti 1021. We either treated S. meliloti 1021 wild-type cells with 0.5 mM IAA, 1021+, or use a derivative, RD64, of the same strain harboring an additional pathway
for IAA biosynthesis (converting tryptophan into IAA via indoleacetamide). We assayed the activity of tricarboxylic acid cycle
(TCA) key enzymes and found that activity of citrate synthase and α-ketoglutarate dehydrogenase were increased in both 1021+
and RD64 as compared to the wild-type strain. We also showed that the intracellular acetyl-CoA content was enhanced in both
RD64 and 1021+ strains when compared to the control strain. The activity of key enzymes, utilizing acetyl-CoA for poly-β-hydroxybutyrate
(PHB) biosynthesis, was also induced. The PHB level measured in these cells were significantly higher than that found in control
cells. Moreover, 4-week-long survival experiments showed that 80% of 1021 cells died, whereas 50% of RD64 cells were viable.
Medicago truncatula plants nodulated by RD64 (Mt-RD64) showed an induction of both acetylene reduction activity and stem dry weight production. 相似文献
65.
Manuela Mancini Sara Petta Giovanni Martinelli Enza Barbieri Maria A. Santucci 《Journal of cellular biochemistry》2010,109(2):320-328
The mammalian target of rapamycin (mTOR) is one target of BCR‐ABL fusion gene of chronic myeloid leukemia (CML). Moreover, it drives a compensatory route to Imatinib mesylate (IM) possibly involved in the progression of leukemic progenitors towards a drug‐resistant phenotype. Accordingly, mTOR inhibitors are proposed for combined therapeutic strategies in CML. The major caveat in the use of mTOR inhibitors for cancer therapy comes from the induction of an mTOR‐phosphatidylinositol 3 kinase (PI3k) feedback loop driving the retrograde activation of Akt. Here we show that the rapamycin derivative RAD 001 (everolimus, Novartis Institutes for Biomedical Research) inhibits mTOR and, more importantly, revokes mTOR late re‐activation in response to IM. RAD 001 interferes with the assembly of both mTOR complexes: mTORC1 and mTORC2. The inhibition of mTORC2 results in the de‐phosphorylation of Akt at Ser473 in the hydrophobic motif of C‐terminal tail required for Akt full activation and precludes Akt re‐phosphorylation in response to IM. Moreover, RAD 001‐induced inhibition of Akt causes the de‐phosphorylation of tuberous sclerosis tumor suppressor protein TSC2 at 14‐3‐3 binding sites, TSC2 release from 14‐3‐3 sigma (restoring its inhibitory function on mTORC1) and nuclear import (promoting the nuclear translocation of cyclin‐dependent kinase [CDK] inhibitor p27Kip1, the stabilization of p27Kip1 ligand with CDK2, and the G0/G1 arrest). RAD 001 cytotoxicity on cells not expressing the BCR‐ABL fusion gene or its p210 protein tyrosine kinase (TK) activity suggests that the inhibition of normal hematopoiesis may represent a drug side effect. J. Cell. Biochem. 109: 320–328, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
66.
67.
Elisa?Giuntini Marco?Bazzicalupo Maurizio?Castaldini Arturo?Fabiani Nerino?Miclaus Raimondo?Piccolo Giancarlo?Ranalli Francesca?Santomassimo Stefano?Zanobini Alessio?MengoniEmail author 《Annals of microbiology》2006,56(2):83
The industrial production of olive oil is accompanied by the accumulation of large quantities of by-products from the olive milling industry that are commonly dispersed as fertilisers, which are nowadays suspected to have potential toxic effects on is omicroflora. The aim of this work has been the investigation of the genetic diversity of bacterial communities present in soil treated with olive husks focusing on the dinitrogen-fixing bacteria.nifH genes were amplified from total soil DNA using universal primers, cloned and typed by restriction analysis and sequencing of representative haplotypes. On the same samples, DGGE analysis on amplified 16S rDNA was performed aiming at monitoring modifications in the total community pattern. Results showed a high genetic diversity ofnifH genes within the community, which was well in agreement with the total community profiles obtained by DGGE on 16SrDNA. Most of thenifH gene fragments (19 out of 32) were found to be similar to sequences related with clostridia. 相似文献
68.
Piccolella E Spadaro F Ramoni C Marinari B Costanzo A Levrero M Thomson L Abraham RT Tuosto L 《Journal of immunology (Baltimore, Md. : 1950)》2003,170(6):2895-2903
We have recently observed that CD28 engagement initiates a signaling pathway leading to the activation of I kappa B kinase (IKK) complex and, consequently, to NF-kappa B activation, and we identified Vav-1 as an important mediator of this function. Here we report for the first time that Vav-1 constitutively associates with IKK alpha in both Jurkat and primary CD4(+) T cells. Vav-1/IKK alpha association is mediated by their helix-loop-helix domains, does not involve IKK beta, and is functionally relevant in that Vav-1-associated IKK alpha kinase activity is increased following CD28 engagement by B7. Moreover, we demonstrate that CD28-induced NF-kappa B activation is augmented by both IKK alpha and Vav-1, but not IKK beta. Confocal microscopy showed that endogenous Vav-1 and IKK alpha, but not IKK beta, were recruited to the membrane and colocalized in response to CD28 stimulation. Taken together, these data evidence that Vav-1 plays a key role in the control of NF-kappa B pathway by targeting IKK alpha in the T cell membrane and favoring its activation in response to CD28 stimulation. 相似文献
69.
Reorganization of actin cytoskeleton by the phosphoinositide metabolite glycerophosphoinositol 4-phosphate
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Mancini R Piccolo E Mariggio' S Filippi BM Iurisci C Pertile P Berrie CP Corda D 《Molecular biology of the cell》2003,14(2):503-515
Glycerophosphoinositol 4-phosphate (GroPIns-4P) is a biologically active, water-soluble phospholipase A metabolite derived from phosphatidylinositol 4-phosphate, whose cellular concentrations have been reported to increase in Ras-transformed cells. It is therefore important to understand its biological activities. Herein, we have examined whether GroPIns-4P can regulate the organization of the actin cytoskeleton, because this could be a Ras-related function involved in cell motility and metastatic invasion. We find that in serum-starved Swiss 3T3 cells, exogenously added GroPIns-4P rapidly and potently induces the formation of membrane ruffles, and, later, the formation of stress fibers. These actin structures can be regulated by the small GTPases Cdc42, Rac, and Rho. To analyze the mechanism of action of GroPIns-4P, we selectively inactivated each of these GTPases. GroPIns-4P requires active Rac and Rho, but not Cdc42, for ruffle and stress fiber formation, respectively. Moreover, GroPIns-4P induces a rapid translocation of the green fluorescent protein-tagged Rac into ruffles, and increases the fraction of GTP-bound Rac, in intact cells. The activation of Rac by GroPIns-4P was near maximal and long-lasting. Interestingly, this feature seems to be critical in the induction of actin ruffles by GroPIns-4P. 相似文献
70.
Natural abundance of 15N in soils along forest-to-pasture chronosequences in the western Brazilian Amazon Basin 总被引:1,自引:0,他引:1
We examined the natural abundance of 15N in soil profiles along two chronosequences in the western Brazilian Amazon Basin state of Rondônia, to investigate possible mechanisms for changes to soil nitrogen sources and transformations that occur as a result of land use. One chronosequence consisted of forest and 3-, 5- and 20-year-old pasture, the other of forest and 8- and 20-year-old pasture. The 15N values of surface soil and soil to 1 m depth in the native forest ranged from 9.8 to 13.6 and were higher than reported for temperate forest soils. Fractionation associated with nitrification and denitrification and selective losses of 15N-depleted nitrate, could potentially result in a strong enrichment of nitrogen in soil organic matter over the time scale of soil development in highly weathered tropical soils. Pasture surface soils were 1–3, depleted in 15N compared with forest soils. Lower 15N values in 20-year-old pastures is consistent with greater cumulative inputs of 15N-depleted atmospheric-derived nitrogen, fixed by free-living bacteria associated with planted pasture grasses in older pastures, or differential plant utilization of soil inorganic N pools with different 15N values. The pattern of 15N values following conversion of forest to agricultural use differs from the pattern in the temperate zone, where pasture or cultivated soils are typically more enriched in 15N than the forest soils from which they were derived. 相似文献