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Elmar Schiebel - One of the best experts on this subject based on the ideXlab platform.
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characterization of spindle pole body duplication reveals a regulatory role for nuclear pore complexes
Journal of Cell Biology, 2017Co-Authors: Diana Rüthnick, Annett Neuner, Franziska Dietrich, Daniel Kirrmaier, Michael Knop, Ulrike Engel, Elmar SchiebelAbstract:The spindle pole body (SPB) of budding yeast duplicates once per cell cycle. In G1, the satellite, an SPB precursor, assembles next to the mother SPB (mSPB) on the cytoplasmic side of the nuclear envelope (NE). How the growing satellite subsequently inserts into the NE is an open question. To address this, we have uncoupled satellite growth from NE insertion. We show that the bridge structure that separates the mSPB from the satellite is a distance holder that prevents deleterious fusion of both structures. Binding of the γ-tubulin receptor Spc110 to the central plaque from within the nucleus is important for NE insertion of the new SPB. Moreover, we provide evidence that a nuclear pore complex associates with the duplicating SPB and helps to insert the SPB into the NE. After SPB insertion, membrane-associated proteins including the conserved Ndc1 encircle the SPB and retain it within the NE. Thus, uncoupling SPB growth from NE insertion unmasks functions of the duplication machinery.
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interaction of the yeast γ tubulin complex binding protein spc72p with kar1p is essential for microtubule function during karyogamy
The EMBO Journal, 1999Co-Authors: Gislene Pereira, Michael Knop, Ulrike Grueneberg, Elmar SchiebelAbstract:The spindle pole body component Kar1p has a function in nuclear fusion during conjugation, a process known as karyogamy. The molecular role of Kar1p during this process is poorly understood. Here we show that the yeast gamma-tubulin complex-binding protein Spc72p interacts directly with the N-terminal domain of Kar1p, thereby targeting the gamma-tubulin complex to the half bridge, a substructure of the spindle pole body, where it organizes microtubules. This binding of Spc72p to Kar1p has only a minor role during vegetative growth, whereas it becomes essential for karyogamy in mating cells, explaining the important role of Kar1p in this process. We also show that the localization of Spc72p within the spindle pole body changes throughout the cell cycle and even more strongly in response to mating pheromone. Taken together, these observations suggest that the relocalization of Spc72p within the spindle pole body is the 'landmark' event in the pheromone-induced reorganization of the cytoplasmic microtubules.
Xavier Lambin - One of the best experts on this subject based on the ideXlab platform.
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living on the edge the role of field margins for common Vole microtus arvalis populations in recently colonised mediterranean farmland
Agriculture Ecosystems & Environment, 2016Co-Authors: Ruth Rodriguezpastor, Xavier Lambin, Juan Jose Luquelarena, Francois MougeotAbstract:Acknowledgments RRP was supported by a PhD-studentship from the University of Valladolid (co-funded by Banco Santander, RR 30/04/2014). Financial support was provided by ECOCYCLES (BIODIVERSA 2008, Era-net European project, EUI2008-03658 and NERC NE/G002045/1 to XL) and ECOVole projects (CGL2012-35348; Ministerio de Economia y Competitividad of Spain). The article also contributes to project ECOTULA (CGL2015-66962-C2-1-R). We held all the necessary licenses and permits for conducting this work (JJLL, FM and RRP held animal experimentation permits of level B for Spain, and a capture permit was provided by the Consejeria de Fomento y Medio Ambiente, Junta de Castilla y Leon (Expte: EP/CYL/665/2014)). We thank two anonymous reviewers for providing and constructive comments to improve the manuscript.
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hierarchical spatial segregation of two mediterranean Vole species the role of patch network structure and matrix composition
Oecologia, 2016Co-Authors: Xavier Lambin, Ricardo Pita, Antonio Mira, Pedro BejaAbstract:According to ecological theory, the coexistence of competitors in patchy environments may be facilitated by hierarchical spatial segregation along axes of environmental variation, but empirical evidence is limited. Cabrera and water Voles show a metapopulation-like structure in Mediterranean farmland, where they are known to segregate along space, habitat, and time axes within habitat patches. Here, we assess whether segregation also occurs among and within landscapes, and how this is influenced by patch-network and matrix composition. We surveyed 75 landscapes, each covering 78 ha, where we mapped all habitat patches potentially suitable for Cabrera and water Voles, and the area effectively occupied by each species (extent of occupancy). The relatively large water Vole tended to be the sole occupant of landscapes with high habitat amount but relatively low patch density (i.e., with a few large patches), and with a predominantly agricultural matrix, whereas landscapes with high patch density (i.e., many small patches) and low agricultural cover, tended to be occupied exclusively by the small Cabrera Vole. The two species tended to co-occur in landscapes with intermediate patch-network and matrix characteristics, though their extents of occurrence were negatively correlated after controlling for environmental effects. In combination with our previous studies on the Cabrera-water Vole system, these findings illustrated empirically the occurrence of hierarchical spatial segregation, ranging from within-patches to among-landscapes. Overall, our study suggests that recognizing the hierarchical nature of spatial segregation patterns and their major environmental drivers should enhance our understanding of species coexistence in patchy environments.
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spatial synchrony in field Vole microtus agrestis abundance in a coniferous forest in northern england the role of Vole eating raptors
Journal of Applied Ecology, 2000Co-Authors: Steve J Petty, Xavier Lambin, Thomas N Sherratt, Christopher Thomas, James L Mackinnon, C F Coles, M Davison, Brian LittleAbstract:1. The regional synchrony hypothesis (RSH) states that synchrony in microtine abundance over large geographical areas is caused by nomadic avian predators that specialize on small mammals for food. This has proved a difficult hypothesis to test because experiments at an appropriate scale are almost impossible. 2. We used the decline of the most abundant, nomadic Vole‐eating raptors in an extensive conifer forest in northern England (Kielder Forest) as a natural experiment to evaluate their influence on synchronizing Voles at different spatial scales. Field Vole populations fluctuated on a 3–4‐year cycle of abundance, similar to the periodicity in central Fennoscandia. 3. Over a 23‐year period, the combined numbers and density of kestrels and short‐eared owls significantly declined. If these raptors were responsible for synchronizing Vole abundance, the decline should have been associated with a decrease in synchrony. We could find no change in synchrony during the period of the greatest decline in kestrel and short‐eared owl numbers (1980–97). 4. In Kielder, Vole abundance has been shown to change in a wave‐like manner, with synchrony in the direction of the wave being 5–10‐fold smaller than that reported in Fennoscandia. Tawny owls are sedentary and the most abundant Vole‐eating raptor in our study area, and might have an equalizing influence on Vole abundance over smaller areas if they foraged in a density‐dependent manner and responded functionally to increasing Vole density. If this was the case, spatial variability in Vole density should have been less in occupied than unoccupied owl territories, especially in years of low Vole density when owls could take a larger proportion of the standing crop of Voles. Even though tawny owls caught a significant proportion of the Vole population, we could find no difference in variation in Vole density between owl territories that were unoccupied, occupied with no breeding attempt, or occupied with a successful breeding attempt. 5. We conclude that the small‐scale synchrony in field Vole abundance is unlikely to be caused by avian predators. Instead, it is more likely to be related to the pattern of clear‐cutting that has developed in Kielder, which restricts Vole dispersal. If this assumption is correct, we would predict more widespread synchrony in Vole abundance in first‐generation forests when extensive areas are planted over short periods of time, and this is supported by anecdotal evidence. These conclusions indicate that foresters may be able to manipulate the spatial dynamics of Voles and Vole predators by varying patch sizes within forests.
Mark Puder - One of the best experts on this subject based on the ideXlab platform.
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fish oil emulsion reduces liver injury and liver transplantation in children with intestinal failure associated liver disease a multicenter integrated study
The Journal of Pediatrics, 2021Co-Authors: Kathleen M. Gura, Muralidhar H Premkumar, Kara L Calkins, Mark PuderAbstract:OBJECTIVE To compare the aspartate aminotransferase to platelet ratio index, liver transplantation, and mortality rates between children with intestinal failure-associated liver disease who received fish oil lipid emulsion (FOLE) or soybean oil intravenous lipid emulsion (SOLE). STUDY DESIGN In this multicenter integrated analysis, FOLE recipients (1 g/kg/d) (n = 189) were compared with historical controls administered SOLE (≤3 g/kg/d) (n = 73). RESULTS Compared with SOLE, FOLE recipients had a higher direct bilirubin level at baseline (5.8 mg/dL vs 3.0 mg/dL; P < .0001). Among FOLE recipients, 65% experienced cholestasis resolution vs 16% of SOLE recipients (P < .0001). The aspartate aminotransferase to platelet ratio index scores improved in FOLE recipients (1.235 vs 0.810 and 0.758, P < .02) but worsened in SOLE recipients (0.540 vs 2.564 and 2.098; P ≤ .0003) when baseline scores were compared with cholestasis resolution and end of study, respectively. Liver transplantation was reduced in FOLE vs SOLE (4% vs 12%; P = .0245). The probability of liver transplantation in relation to baseline direct or conjugated bilirubin (DB) was lower in FOLE vs SOLE recipients (1% vs 9% at DB of 2 mg/dL; 8% vs 35% at DB of 12.87 mg/dL; P = .0022 for both). Death rates were similar (FOLE vs SOLE: 10% vs 14% at DB of 2 mg/dL; 17% vs 23% at a DB of 12.87 mg/dL; P = .36 for both). CONCLUSIONS FOLE recipients experienced a higher rate of cholestasis resolution, lower aspartate aminotransferase to platelet ratio index, and fewer liver transplants compared with SOLE. This study demonstrates that FOLE may be the preferred parenteral lipid emulsion in children with intestinal failure-associated liver disease when DB reaches 2 mg/dL. TRIAL REGISTRATION Clinicaltrials.gov: NCT00910104 and NCT00738101.
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intravenous fish oil monotherapy as a source of calories and fatty acids promotes age appropriate growth in pediatric patients with intestinal failure associated liver disease
The Journal of Pediatrics, 2020Co-Authors: Kathleen M. Gura, Muralidhar H Premkumar, Kara L Calkins, Mark PuderAbstract:Objective To compare growth in children with intestinal failure-associated liver disease (IFALD) who received a fish oil intravenous lipid emulsion (FOLE) to those who received a soybean oil intravenous lipid emulsion (SOLE). Study design This multisite, retrospective study pair-matched FOLE (n = 82) to SOLE recipients (n = 41) using baseline serum direct bilirubin levels and postmenstrual age. Study subjects received open-label FOLE (1 g/kg/day) until IFALD resolved or parenteral nutrition was stopped. Historical control subjects received SOLE (up to 3 g/kg/day). Growth measures (changes in body weight, height/length, and head circumference), prealbumin, triglycerides, and glucose were compared between groups over time using the Wilcoxon rank-sum test. Results Although changes in all of the growth measures were similar for both groups (P > .05), FOLE recipients demonstrated an overall improved growth trajectory. After 28 weeks, FOLE recipients had a mean body weight within a z score range of −1 to 1 indicating age-appropriate growth. FOLE recipients consistently had higher prealbumin, lower triglyceride, and more normal glucose concentrations over time compared with SOLE recipients. Conclusions Children with IFALD who received FOLE had similar growth and fewer metabolic abnormalities compared with those who received SOLE. Trial registration Clinicaltrials.gov : NCT00910104 and NCT00738101 .
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intravenous fish oil lipid emulsion promotes a shift toward anti inflammatory proresolving lipid mediators
American Journal of Physiology-gastrointestinal and Liver Physiology, 2013Co-Authors: Brian T Kalish, Kathleen M. Gura, Jonathan M Fitzgerald, Samantha Wang, Kyle J Seamon, Karsten Gronert, Mark PuderAbstract:Parenteral nutrition (PN)-associated liver disease (PNALD) is a life-threatening complication of the administration of PN. The development of PNALD may be partly due to the composition of the lipid emulsion administered with PN: soybean oil-based lipid emulsions (SOLE) are associated with liver disease, while fish oil-based lipid emulsions (FOLE) are associated with prevention and improvement of liver disease. The objective of this study was to determine how the choice of lipid emulsion modified the production of bioactive lipid mediators (LMs). We utilized a mouse model of steatosis to study the differential effect of FOLE and SOLE. We subsequently validated these results in serum samples from a small cohort of human infants transitioning from SOLE to FOLE. In mice, FOLE was associated with production of anti-inflammatory, proresolving LMs; SOLE was associated with increased production of inflammatory LMs. In human infants, the transition from SOLE to FOLE was associated with a shift toward a proresolving lipidome. Together, these results demonstrate that the composition of the lipid emulsion directly modifies inflammatory homeostasis.
Larry J Young - One of the best experts on this subject based on the ideXlab platform.
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comparative distribution of central neuropeptide y npy in the prairie microtus ochrogaster and meadow m pennsylvanicus Vole
Peptides, 2013Co-Authors: Caroline M Hostetler, Larry J Young, Leah N Hitchcock, Allison M J Anacker, Andrey E RyabininAbstract:Neuropeptide Y (NPY) has been implicated as a modulator of social behavior, often in a species-specific manner. Comparative studies of closely related Vole species are particularly useful for identifying neural systems involved in social behaviors in both Voles and humans. In the present study, immunohistochemistry was performed to compare NPY-like immunoreactivity (-ir) in brain tissue of the socially monogamous prairie Vole and non-monogamous meadow Vole. Species differences in NPY-ir were observed in a number of regions including the cortex, extended amygdala, septal area, suprachiasmatic nucleus, and intergeniculate leaf. Meadow Voles had higher NPY-ir in all these regions as compared to prairie Voles. No differences were observed in the striatum or hippocampus. The extended amygdala and lateral septum are regions that play a key role in regulation of monogamous behaviors such as pair bonding and paternal care. The present study suggests NPY in these regions may be an additional modulator of these species-specific social behaviors. Meadow Voles had moderately higher NPY-ir in a number of hypothalamic regions, especially in the suprachiasmatic nucleus. Meadow Voles also had much higher levels of NPY-ir in the intergeniculate leaflet, another key region in the regulation of circadian rhythms. Overall, species differences in NPY-ir were observed in a number of brain regions implicated in emotion, stress, circadian, and social behaviors. These findings provide additional support for a role for the NPY system in species-typical social behaviors.
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oxytocin vasopressin and the neuroendocrine basis of pair bond formation
Advances in Experimental Medicine and Biology, 1998Co-Authors: Thomas R Insel, James T Winslow, Larry J YoungAbstract:Several lines of evidence support a role for oxytocin and vasopressin in complex social behaviors, including parental care, sex behavior, and aggression. Recent studies in a monogamous mammal, the prairie Vole, suggest an additional role for both peptides in the formation of pair bonds. Central administration of oxytocin facilitates and administration of an oxytocin antagonist inhibits partner preference formation in female prairie Voles. Conversely, vasopressin facilitates and a V1a receptor antagonist inhibits pair bonding in males. A potential cellular basis for these effects is the species-specific pattern of expression of oxytocin and V1a receptors in reward pathways of the prairie Vole brain. At a molecular level, comparative sequencing of the oxytocin and V1a receptors reveals species differences in the promoter sequences that may guide regional expression in the brain. Transgenic mice created with the 5’ flanking region of the prairie Vole oxytocin receptor gene demonstrate that sequences in this region influence the pattern of expression within the brain. The unique promoter sequences of the prairie Vole OTR and V1a receptor genes and the resulting species-specific pattern of regional expression provide a potential molecular mechanism for the evolution of pair bonding behaviors and a cellular basis for monogamy.
Thomas R Insel - One of the best experts on this subject based on the ideXlab platform.
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oxytocin vasopressin and the neuroendocrine basis of pair bond formation
Advances in Experimental Medicine and Biology, 1998Co-Authors: Thomas R Insel, James T Winslow, Larry J YoungAbstract:Several lines of evidence support a role for oxytocin and vasopressin in complex social behaviors, including parental care, sex behavior, and aggression. Recent studies in a monogamous mammal, the prairie Vole, suggest an additional role for both peptides in the formation of pair bonds. Central administration of oxytocin facilitates and administration of an oxytocin antagonist inhibits partner preference formation in female prairie Voles. Conversely, vasopressin facilitates and a V1a receptor antagonist inhibits pair bonding in males. A potential cellular basis for these effects is the species-specific pattern of expression of oxytocin and V1a receptors in reward pathways of the prairie Vole brain. At a molecular level, comparative sequencing of the oxytocin and V1a receptors reveals species differences in the promoter sequences that may guide regional expression in the brain. Transgenic mice created with the 5’ flanking region of the prairie Vole oxytocin receptor gene demonstrate that sequences in this region influence the pattern of expression within the brain. The unique promoter sequences of the prairie Vole OTR and V1a receptor genes and the resulting species-specific pattern of regional expression provide a potential molecular mechanism for the evolution of pair bonding behaviors and a cellular basis for monogamy.
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a role for central vasopressin in pair bonding in monogamous prairie Voles
Nature, 1993Co-Authors: James T Winslow, C.s. Carter, N Hastings, C R Harbaugh, Thomas R InselAbstract:MONOGAMOUS social organization is characterized by selective affiliation with a partner, high levels of paternal behaviour and, in many species, intense aggression towards strangers for defence of territory, nest and mate1,2. Although much has been written about the evolutionary causes of monogamy, little is known about the proximate mechanisms for pair bonding in monogamous mammals2,3. The prairie Vole, Microtus ochrogaster, is a monogamous, biparental rodent which exhibits long-term pair bonds characterized by selective affiliation (partner preference) and aggression4,5. Here we describe the rapid development of both selective aggression and partner preferences following mating in the male of this species. We hypothesized that either argininevasopressin (AVP) or oxytocin (OT), two nine-amino-acid neuropeptides with diverse forebrain projections, could mediate the development of selective aggression and affiliation. This hypothesis was based on the following observations: (1) monogamous and polygamous Voles differ specifically in the distribution of forebrain AVP and OT receptors6,7; (2) AVP innervation in the prairie Vole brain is sexually dimorphic and important for paternal behaviour8; (3) central AVP pathways have been previously implicated in territorial displays and social memory9,10; and (4) central OT pathways have been previously implicated in affiliative behaviours11. We now demonstrate that central AVP is both necessary and sufficient for selective aggression and partner preference formation, two critical features of pair bonding in the monogamous prairie Vole.
