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991.
992.
Jaimie T. A. Dick Mhairi E. Alexander Jonathan M. Jeschke Anthony Ricciardi Hugh J. MacIsaac Tamara B. Robinson Sabrina Kumschick Olaf L. F. Weyl Alison M. Dunn Melanie J. Hatcher Rachel A. Paterson Keith D. Farnsworth David M. Richardson 《Biological invasions》2014,16(4):735-753
Invasion ecology urgently requires predictive methodologies that can forecast the ecological impacts of existing, emerging and potential invasive species. We argue that many ecologically damaging invaders are characterised by their more efficient use of resources. Consequently, comparison of the classical ‘functional response’ (relationship between resource use and availability) between invasive and trophically analogous native species may allow prediction of invader ecological impact. We review the utility of species trait comparisons and the history and context of the use of functional responses in invasion ecology, then present our framework for the use of comparative functional responses. We show that functional response analyses, by describing the resource use of species over a range of resource availabilities, avoids many pitfalls of ‘snapshot’ assessments of resource use. Our framework demonstrates how comparisons of invader and native functional responses, within and between Type II and III functional responses, allow testing of the likely population-level outcomes of invasions for affected species. Furthermore, we describe how recent studies support the predictive capacity of this method; for example, the invasive ‘bloody red shrimp’ Hemimysis anomala shows higher Type II functional responses than native mysids and this corroborates, and could have predicted, actual invader impacts in the field. The comparative functional response method can also be used to examine differences in the impact of two or more invaders, two or more populations of the same invader, and the abiotic (e.g. temperature) and biotic (e.g. parasitism) context-dependencies of invader impacts. Our framework may also address the previous lack of rigour in testing major hypotheses in invasion ecology, such as the ‘enemy release’ and ‘biotic resistance’ hypotheses, as our approach explicitly considers demographic consequences for impacted resources, such as native and invasive prey species. We also identify potential challenges in the application of comparative functional responses in invasion ecology. These include incorporation of numerical responses, multiple predator effects and trait-mediated indirect interactions, replacement versus non-replacement study designs and the inclusion of functional responses in risk assessment frameworks. In future, the generation of sufficient case studies for a meta-analysis could test the overall hypothesis that comparative functional responses can indeed predict invasive species impacts. 相似文献
993.
Tamara Münkemüller Laure Gallien Sébastien Lavergne Julien Renaud Cristina Roquet Sylvain Abdulhak Stefan Dullinger Luc Garraud Antoine Guisan Jonathan Lenoir Jens‐Christian Svenning Jérémie Van Es Pascal Vittoz Wolfgang Willner Thomas Wohlgemuth Niklaus E. Zimmermann Wilfried Thuiller 《Global Ecology and Biogeography》2014,23(6):620-632
994.
Patrick C. Thiaville Basma El Yacoubi Ludovic Perrochia Arnaud Hecker Magali Prigent Jennifer J. Thiaville Patrick Forterre Olivier Namy Tamara Basta Valérie de Crécy-Lagard 《Eukaryotic cell》2014,13(9):1222-1231
Threonylcarbamoyladenosine (t6A) is a universal modification located in the anticodon stem-loop of tRNAs. In yeast, both cytoplasmic and mitochondrial tRNAs are modified. The cytoplasmic t6A synthesis pathway was elucidated and requires Sua5p, Kae1p, and four other KEOPS complex proteins. Recent in vitro work suggested that the mitochondrial t6A machinery of Saccharomyces cerevisiae is composed of only two proteins, Sua5p and Qri7p, a member of the Kae1p/TsaD family (L. C. K. Wan et al., Nucleic Acids Res. 41:6332–6346, 2013, http://dx.doi.org/10.1093/nar/gkt322). Sua5p catalyzes the first step leading to the threonyl-carbamoyl-AMP intermediate (TC-AMP), while Qri7 transfers the threonyl-carbamoyl moiety from TC-AMP to tRNA to form t6A. Qri7p localizes to the mitochondria, but Sua5p was reported to be cytoplasmic. We show that Sua5p is targeted to both the cytoplasm and the mitochondria through the use of alternative start sites. The import of Sua5p into the mitochondria is required for this organelle to be functional, since the TC-AMP intermediate produced by Sua5p in the cytoplasm is not transported into the mitochondria in sufficient amounts. This minimal t6A pathway was characterized in vitro and, for the first time, in vivo by heterologous complementation studies in Escherichia coli. The data revealed a potential for TC-AMP channeling in the t6A pathway, as the coexpression of Qri7p and Sua5p is required to complement the essentiality of the E. coli
tsaD mutant. Our results firmly established that Qri7p and Sua5p constitute the mitochondrial pathway for the biosynthesis of t6A and bring additional advancement in our understanding of the reaction mechanism. 相似文献
995.
Mohammad R. Abdollahi Tamara Sirey Bruce E. Hayward Kelly Springell Mushtaq Ahmed Peter Corry Neil Stoodley Graham R. Taylor Eamonn Sheridan 《American journal of human genetics》2009,85(5):737-744
The critical importance of cytoskeletal function for correct neuronal migration during development of the cerebral cortex has been underscored by the identities of germline mutations underlying a number of human neurodevelopmental disorders. The proteins affected include TUBA1A, a major α-tubulin isoform, and microtubule-associated components such as doublecortin, and LIS1. Mutations in these genes are associated with the anatomical abnormality lissencephaly, which is believed to reflect failure of neuronal migration. An important recent observation has been the dependence of cortical neuronal migration upon acetylation of α-tubulin at lysine 40 by the histone acetyltransferase Elongator complex. Here, we describe a recognizable autosomal recessive syndrome, characterized by generalized polymicrogyria in association with optic nerve hypoplasia (PMGOH). By autozygosity mapping, we show that the molecular basis for this condition is mutation of the TUBA8 gene, encoding a variant α-tubulin of unknown function that is not susceptible to the lysine 40 acetylation that regulates microtubule function during cortical neuron migration. Together with the unique expression pattern of TUBA8 within the developing cerebral cortex, these observations suggest a role for this atypical microtubule component in regulating mammalian brain development. 相似文献
996.
Tamara I. Balakhnina Anatoly B. Gavrilov Teresa M. Włodarczyk Aneta Borkowska Magdalena Nosalewicz Irina R. Fomina 《Plant Growth Regulation》2009,57(2):127-135
Barley (Hordeum vulgare L.) seeds were soaked in aqueous 10−4 M dihydroquercetin (DHQ) to examine its influence on seed germination and further growth of seedlings under optimal soil
watering and flooding conditions. The adaptive potential of the plants was estimated by the content of thiobarbituric acid
reactive substances (TBARs) and the activity of ascorbate peroxidase (AsP). High-grade seeds were germinated evenly under
(−DHQ)- and (+DHQ)-treatments. Low-grade seeds soaked in DHQ, showed no mold and twofold germination rate in comparison with
the same seeds soaked in water. The seedlings grown from the similarly germinated seeds did not differ from each other in
the shoot growth, independent of the DHQ-pretreatment. The root growth was higher in DHQ-pretreated plants. Soil flooding
suppressed the shoot and root growth rates in non-pretreated and DHQ-pretreated plants, however TBARs content was lower in
the roots and leaves of (+DHQ)-seedlings as compared to the (−DHQ)-ones. The activity of AsP increased more significantly
in the (+DHQ)-plants. The ratio between TBARs content and the AsP activity was lower in the leaves of (+DHQ)-plants both under
optimal soil conditions and flooding. Thus, the treatment of low-grade barley seeds with DHQ protects the seeds against mold
and increases adaptive potential of the seedlings. 相似文献
997.
998.
Carola A. M. Yovanovich Lucas D. Jungblut Tamara Heer Andrea G. Pozzi Dante A. Paz 《Cell and tissue research》2009,336(1):1-9
The vertebrate olfactory system has fascinated neurobiologists over the last six decades because of its ability to replace
its neurons and synaptic connections continuously throughout adult life, under both physiological and pathological conditions.
Among the factors that are proposed to be involved in this regenerative potential, brain-derived neurotrophic factor (BDNF)
is a candidate for having an important role in the neuronal turnover in the olfactory epithelium (OE) because of its well-documented
neurogenic and trophic effects throughout the nervous system. The aim of the present study was to generate a suitable model
to study the participation of BDNF in the recovery of the OE after injury in vivo. We developed an experimental design in
which the OE of Rhinella arenarum tadpoles could be easily and selectively damaged by immersing the animals in ZnSO4 solutions of various concentrations for differing time periods. Image analysis of histological sections showed that different
combinations of each of these conditions produced statistically different degrees of injury to the olfactory tissue. We also
observed that the morphology of the OE was restored within a few days of recovery after ZnSO4 treatment. Immunohistochemical analysis of BDNF was performed with an antiserum whose specificity was confirmed by Western
blotting, and which showed drastic changes in the abundance and distribution pattern of this neurotrophin in the damaged olfactory
system. Our results thus suggest that BDNF is involved in the regeneration of the OE of amphibian larvae, and that our approach
is suitable for further investigations of this topic.
This work was supported by grants from CONICET (PIP 5842), Universidad de Buenos Aires (UBACYT X131) and ANPCYT (PICT 32219). 相似文献
999.
1000.
Tamara Žáčková Ilkka Y Järvelä Juha S Tapanainen Jaroslav Feyereisl 《Reproductive biology and endocrinology : RB&E》2009,7(1):151-8