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Stefanie Wagner Isabel Sorg Matteo Degiacomi Laure Journet Matteo Dal Peraro Guy R. Cornelis 《Molecular microbiology》2009,71(3):692-701
The length of the Yersinia injectisome needle is determined by the protein YscP, which could act as a molecular ruler. The analysis of the correlation between the size of YscP and the needle length in seven wild-type strains of Yersinia enterocolitica reinforced this hypothesis but hinted that the secondary structure of YscP might influence needle length. Hence, 11 variants of YscP515 were generated by multiple Pro or Gly substitutions. The needle length changed in inverse function of the helical content, indicating that not only the number of residues but also their structure controls length. Taking the secondary motifs into account, Pro/Gly-variants were subjected to in silico modelling to simulate the extension of YscP upon needle growth. The calculated lengths when the helical content is preserved correlated strikingly with the measured needle length, with a constant difference of ∼29 nm, which corresponds approximately to the size of the basal body. These data support the ruler model and show that the functional ruler has a helical structure. 相似文献
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Daniela Barro‐Trastoy Esther Carrera Jorge Baos Julia Palau‐Rodríguez Omar Ruiz‐Rivero Pablo Tornero Jos M. Alonso Isabel Lpez‐Díaz María Dolores Gmez Miguel A. Prez‐Amador 《The Plant journal : for cell and molecular biology》2020,102(5):1026-1041
Ovule primordia formation is a complex developmental process with a strong impact on the production of seeds. In Arabidopsis this process is controlled by a gene network, including components of the signalling pathways of auxin, brassinosteroids (BRs) and cytokinins. Recently, we have shown that gibberellins (GAs) also play an important role in ovule primordia initiation, inhibiting ovule formation in both Arabidopsis and tomato. Here we reveal that BRs also participate in the control of ovule initiation in tomato, by promoting an increase on ovule primordia formation. Moreover, molecular and genetic analyses of the co‐regulation by GAs and BRs of the control of ovule initiation indicate that two different mechanisms occur in tomato and Arabidopsis. In tomato, GAs act downstream of BRs. BRs regulate ovule number through the downregulation of GA biosynthesis, which provokes stabilization of DELLA proteins that will finally promote ovule primordia initiation. In contrast, in Arabidopsis both GAs and BRs regulate ovule number independently of the activity levels of the other hormone. Taken together, our data strongly suggest that different molecular mechanisms could operate in different plant species to regulate identical developmental processes even, as for ovule primordia initiation, if the same set of hormones trigger similar responses, adding a new level of complexity. 相似文献
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Ilse Van Gucht Josephina A.N. Meester Jotte Rodrigues Bento Maaike Bastiaansen Jarl Bastianen Ilse Luyckx Lotte Van Den Heuvel Cédric H.G. Neutel Pieter-Jan Guns Mandy Vermont Erik Fransen Melanie H.A.M. Perik Joe Davis Velchev Maaike Alaerts Dorien Schepers Silke Peeters Isabel Pintelon Abdulrahman Almesned Aline Verstraeten 《American journal of human genetics》2021,108(6):1115-1125
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Mario Rincón-Barrado Sanna Olsson Tamara Villaverde Belén Moncalvillo Lisa Pokorny Alan Forrest Ricarda Riina Isabel Sanmartín 《植物分类学报:英文版》2021,59(5):915-934
Wide-range geographically discontinuous distributions have long intrigued scientists. We explore the role of ecology, geology, and dispersal in the formation of these large-scale disjunctions, using the angiosperm tribe Putorieae (Rubiaceae) as a case study. From DNA sequences of nuclear ITS and six plastid markers, we inferred a phylogeny with 65% of all known Putorieae species. Divergence times, ancestral ranges, and diversification rate shifts were then estimated using Bayesian inference. We further explored species climatic tolerances and performed ancestral niche reconstruction to discriminate among alternative speciation modes, including geographical and ecological vicariance, and ecogeographical, ecological, and dispersal-mediated speciation. As a result, we identified seven major clades in Putorieae, some of which exhibit striking geographical disjunctions, matching the Rand Flora pattern, with sister species in the Canary Islands andeastern and southern Africa. Initial diversification within the tribe occurred in the early Miocene, coincident with a period of climate warming; however, most clades diverged within the last 10 Myr. Aridification and high extinction rates, coupled with ecological vicariance, explain the oldest disjunctions. Adaptation to new environmental conditions, after allopatry, is observed in several clades. Dispersal, either long-distance or via corridors made available by mountain uplift, is behind the most recent disjunctions. Some of these events were followed by ecological speciation and rapid diversification, with species becoming adapted to xeric or increasingly colder continental climates. We show that an integrative approach may help discriminate among speciation modes invoked to explain disjunctions at macroevolutionary time scales, even when extinction has erased the signature of past events. 相似文献
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Isidoro Olmeda Patricia Casino Robert E. Collins Ramón Sendra Sara Callejón Juanjo Huesa Alexei S. Soares Sergi Ferrer Isabel Pardo 《Microbial biotechnology》2021,14(3):1026-1043
Prokaryotic laccases are emergent biocatalysts. However, they have not been broadly found and characterized in bacterial organisms, especially in lactic acid bacteria. Recently, a prokaryotic laccase from the lactic acid bacterium Pediococcus acidilactici 5930, which can degrade biogenic amines, was discovered. Thus, our study aimed to shed light on laccases from lactic acid bacteria focusing on two Pediococcus laccases, P. acidilactici 5930 and Pediococcus pentosaceus 4816, which have provided valuable information on their biochemical activities on redox mediators and biogenic amines. Both laccases are able to oxidize canonical substrates as ABTS, ferrocyanide and 2,6-DMP, and non-conventional substrates as biogenic amines. With ABTS as a substrate, they prefer an acidic environment and show sigmoidal kinetic activity, and are rather thermostable. Moreover, this study has provided the first structural view of two lactic acid bacteria laccases, revealing new structural features not seen before in other well-studied laccases, but which seem characteristic for this group of bacteria. We believe that understanding the role of laccases in lactic acid bacteria will have an impact on their biotechnological applications and provide a framework for the development of engineered lactic acid bacteria with enhanced properties. 相似文献
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Cortés-Sarabia Karen Bautista-Santos Isabel Cisneros-Sarabia Alondra Parra-Rojas Isela Estrada-Moreno Ana Karen Flores-Alfaro Eugenia Fernández-Tilapa Gloria Ramírez-Peralta Arturo Vences-Velázquez Amalia 《International journal of peptide research and therapeutics》2021,27(1):413-420
International Journal of Peptide Research and Therapeutics - Gardnerella vaginalis produces vaginolysin (VLY), a cholesterol-dependent cytolysin, responsible of the cellular lysis and epithelial... 相似文献