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Major Effects (major + effects)
Selected AbstractsTherapeutic aspects of growth hormone and insulin-like growth factor-I treatment on visceral fat and insulin sensitivity in adultsDIABETES OBESITY & METABOLISM, Issue 1 2007K. C. J. Yuen Growth hormone (GH) is generally considered to exert anti-insulin actions, whereas insulin-like growth factor I (IGF-I) has insulin-like properties. Paradoxically, GH deficient adults and those with acromegaly are both predisposed to insulin resistance, but one cannot extrapolate from these pathological conditions to determine the normal metabolic roles of GH and IGF-I on glucose homeostasis. High doses of GH treatment have major effects on lipolysis, which plays a crucial role in promoting its anti-insulin effects, whereas IGF-I acts as an insulin sensitizer that does not exert any direct effect on lipolysis or lipogenesis. Under physiological conditions, the insulin-sensitizing effect of IGF-I is only evident after feeding when the bioavailability of circulating IGF-I is increased. In contrast, many studies in GH deficient adults have consistently shown that GH replacement improves the body composition profile although these studies differ considerably in terms of age, the presence or absence of multiple pituitary hormone deficiency, and whether GH deficiency was childhood or adult-onset. However, the improvement in body composition does not necessarily translate into improvements in insulin sensitivity presumably due to the anti-insulin effects of high doses of GH therapy. More recently, we have found that a very low dose GH therapy (0.1 mg/day) improved insulin sensitivity without affecting body composition in GH-deficient adults and in subjects with metabolic syndrome, and we postulate that these effects are mediated by its ability to increase free ,bioavailable' IGF-I without the induction of lipolysis. These results raise the possibility that this low GH dose may play a role in preventing the decline of ,-cell function and the development of type 2 diabetes in these "high risk" subjects. [source] Drug education: myth and realityDRUG AND ALCOHOL REVIEW, Issue 1 2001GRAEME HAWTHORNE Abstract Recently there has been an increase in Australian public funds for drug education. The accompanying rhetoric asserts that it is to enable abstinence among young people. This contradicts some State Government education guidelines endorsing harm minimization. A literature search of the key electronic databases, drug agency libraries, the Internet and reference lists identified evaluation research in school-based drug education. There is little evidence to support the new public rhetoric. The predictors of adolescent drug use are social and personal; schools can have little effect on these. Four models of drug education are described. Schools, however, mix-and-match activities from different models, and exposure is too slight for major effects on behaviours. Although methodological difficulties affect findings, none of the drug education models show consistent behavioural effects over time. There is a mismatch between the new public rhetoric and the evaluation research literature. Reasons for this are explored, including that there are two stakeholder groups, one with exaggerated ideological anti-drug messages and the other with more realistic perspectives about what schools can reasonably achieve. The paradox is that the rhetoric is needed for continued funding, yet this same rhetoric sets up criteria which doom drug education to failure. [source] Ascomycete communities in the rhizosphere of field-grown wheat are not affected by introductions of genetically modified Pseudomonas putida WCS358rENVIRONMENTAL MICROBIOLOGY, Issue 11 2005Mareike Viebahn Summary A long-term field experiment (1999,2002) was conducted to monitor effects on the indigenous microflora of Pseudomonas putida WCS358r and two transgenic derivatives constitutively producing phenazine-1-carboxylic acid (PCA) or 2,4-diacetylphloroglucinol (DAPG). The strains were introduced as seed coating on wheat into the same field plots each year. Rhizosphere populations of ascomycetes were analysed using denaturing gradient gel electrophoresis (DGGE). To evaluate the significance of changes caused by the genetically modified microorganisms (GMMs), they were compared with effects caused by a crop rotation from wheat to potato. In the first year, only the combination of both GMMs caused a significant shift in the ascomycete community. After the repeated introductions this effect was no longer evident. However, cropping potato significantly affected the ascomycete community. This effect persisted into the next year when wheat was grown. Clone libraries were constructed from samples taken in 1999 and 2000, and sequence analysis indicated ascomycetes of common genera to be present. Most species occurred in low frequencies, distributed almost evenly in all treatments. However, in 1999 Microdochium occurred in relatively high frequencies, whereas in the following year no Microdochium species were detected. On the other hand, Fusarium -like organisms were low in 1999, and increased in 2000. Both the DGGE and the sequence analysis revealed that repeated introduction of P. putida WCS358r had no major effects on the ascomycete community in the wheat rhizosphere, but demonstrated a persistent difference between the rhizospheres of potato and wheat. [source] Effects of selected polybrominated diphenyl ether flame retard ants on lake trout (Salvelinus namaycush) thymocyte viability, apoptosis, and necrosisENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2005Kelly L. Birchmeier Abstract Polybrominated diphenyl ether (PBDE) flame-retardants have been identified as an emergent contaminants issue in many parts of the world. In vitro analyses were conducted to test the hypothesis that selected PBDEs congeners affect viability, apoptosis, and necrosis of thymocytes from laboratory-reared lake trout (Salvelinus namaycush). At current environmental levels (<1 mg/L), effects of the tested PBDEs on thymocytes were negligible. However, at 100 mg/L, major effects were seen for congener brominated diphenyl ether 47 (BDE-47) and minor effects were seen for congener BDE-99. [source] T-cell interleukin-6 receptor binding in interferon-,-1b-treated multiple sclerosis patientsEUROPEAN JOURNAL OF NEUROLOGY, Issue 6 2000P. Bongioanni Multiple sclerosis (MS) is a T-cell-mediated autoimmune demyelinating disease of the central nervous system, associated with an altered cytokine network. We previously assayed peripheral blood T-lymphocyte binding for two prototypic cytokines, tumour necrosis factor-, (TNF-,) and interleukin-6 (IL-6), and found that T cells from MS patients had significantly more TNF-, and IL-6 receptors than those from healthy controls. In the present work, paralleling a previous one on T-cell TNF-, binding, we studied the effect of interferon (IFN)-,-1b treatment on T-lymphocyte IL-6 binding in patients with relapsing,remitting MS. T cells from MS patients had significantly (P < 0.001) higher amounts of IL-6 receptors than those from controls [292 ± 6 vs. 228 ± 8 (mean ± SEM) receptors per cell, respectively], whereas the ligand-receptor affinity values were similar in the two groups [26.2 ± 0.7 and 25.7 ± 0.4 (mean ± SEM) pmoles/l, respectively]. After a 3-month IFN-,-1b treatment, they showed a significant decrease in IL-6 binding [266 ± 7 (mean ± SEM) receptors per cell]. After 6 and 9 months, T-cell IL-6 Bmax values were even lower [258 ± 8 and 251 ± 8 (mean ± SEM) receptors per cell]. Since an increased IL-6 binding might be linked to a lymphocyte activation, our data give further support for an enhanced immune response in patients with MS. Our data seem to demonstrate that the major effects of IFN-,-1b treatment result in a decrease of T-cell activation. [source] A CENTENNIAL CELEBRATION FOR QUANTITATIVE GENETICSEVOLUTION, Issue 5 2007Derek A. Roff Quantitative genetics is at or is fast approaching its centennial. In this perspective I consider five current issues pertinent to the application of quantitative genetics to evolutionary theory. First, I discuss the utility of a quantitative genetic perspective in describing genetic variation at two very different levels of resolution, (1) in natural, free-ranging populations and (2) to describe variation at the level of DNA transcription. Whereas quantitative genetics can serve as a very useful descriptor of genetic variation, its greater usefulness is in predicting evolutionary change, particularly when used in the first instance (wild populations). Second, I review the contributions of Quantitative trait loci (QLT) analysis in determining the number of loci and distribution of their genetic effects, the possible importance of identifying specific genes, and the ability of the multivariate breeder's equation to predict the results of bivariate selection experiments. QLT analyses appear to indicate that genetic effects are skewed, that at least 20 loci are generally involved, with an unknown number of alleles, and that a few loci have major effects. However, epistatic effects are common, which means that such loci might not have population-wide major effects: this question waits upon (QTL) analyses conducted on more than a few inbred lines. Third, I examine the importance of research into the action of specific genes on traits. Although great progress has been made in identifying specific genes contributing to trait variation, the high level of gene interactions underlying quantitative traits makes it unlikely that in the near future we will have mechanistic models for such traits, or that these would have greater predictive power than quantitative genetic models. In the fourth section I present evidence that the results of bivariate selection experiments when selection is antagonistic to the genetic covariance are frequently not well predicted by the multivariate breeder's equation. Bivariate experiments that combine both selection and functional analyses are urgently needed. Finally, I discuss the importance of gaining more insight, both theoretical and empirical, on the evolution of the G and P matrices. [source] Influence of fault map resolution on pore pressure distribution and secondary hydrocarbon migration; Tune area, North SeaGEOFLUIDS (ELECTRONIC), Issue 2 2006A. E. LOTHE Abstract Pressure and hydrocarbon migration modelling was carried out in the Tune Field area, Viking Graben, offshore Norway. The pressures are considered to be controlled by compartments bounded by mapped faults. Two different interpreted fault maps at the top reservoir level (Brent Group) are used as input to the modelling. First, a low-resolution fault map is used, with only the large faults interpreted, and next, both large and small faults are included. The simulations show high overpressures generated in the western area, in the deeper part of the Viking Graben, and hydrostatic in the eastern areas. A sharp transition zone results from using the low-resolution fault map in the simulations. Small N,S striking faults situated in between the wells have to have higher sealing capacity than expected from juxtaposition analysis alone, to be able to match the overpressures measured in well 30/5-2 and 30/8-1S in the Tune Field, and well 30/8-3 east of Tune. The intermediate pressure in the western part is probably related to flow in the deeper parts of the sedimentary column in the compartment, where well 30/8-3 is situated. The secondary oil migration models show that overpressures have major effects on the migration pathways of hydrocarbons. The level of detail in the fault interpretation is important for simulation results, both for pressure distribution and for hydrocarbon migration. [source] Modelling the effects of loss of soil biodiversity on ecosystem functionGLOBAL CHANGE BIOLOGY, Issue 1 2002H. W. Hunt Abstract There are concerns about whether accelerating worldwide loss of biodiversity will adversely affect ecosystem functioning and services such as forage production. Theoretically, the loss of some species or functional groups might be compensated for by changes in abundance of other species or functional groups such that ecosystem processes are unaffected. A simulation model was constructed for carbon and nitrogen transfers among plants and functional groups of microbes and soil fauna. The model was based on extensive information from shortgrass prairie, and employed stabilizing features such as prey refuges and predator switching in the trophic equations. Model parameters were derived either from the literature or were estimated to achieve a good fit between model predictions and data. The model correctly represented (i) the major effects of elevated atmospheric CO2 and plant species on root and shoot biomass, residue pools, microbial biomass and soil inorganic nitrogen, and (ii) the effects on plant growth of manipulating the composition of the microbial and faunal community. The model was evaluated by comparing predictions to data not used in model development. The 15 functional groups of microbes and soil fauna were deleted one at a time and the model was run to steady state. Only six of the 15 deletions led to as much as a 15% change in abundance of a remaining group, and only two deletions (bacteria and saprophytic fungi) led to extinctions of other groups. Functional groups with greater effect on abundance of other groups were those with greater biomass or greater number of consumers, regardless of trophic position. Of the six deletions affecting the abundance of other groups, only three (bacteria, saprophytic fungi, and root-feeding nematodes) caused as much as 10% changes in indices of ecosystem function (nitrogen mineralization and primary production). While the soil fauna as a whole were important for maintenance of plant production, no single faunal group had a significant effect. These results suggest that ecosystems could sustain the loss of some functional groups with little decline in ecosystem services, because of compensatory changes in the abundance of surviving groups. However, this prediction probably depends on the nature of stabilizing mechanisms in the system, and these mechanisms are not fully understood. [source] The E-economy and the Rise of Technocapitalism: Networks, Firms, and TransportationGROWTH AND CHANGE, Issue 4 2003Luis Suarez-Villa ABSTRACT The e-economy is part of a larger phenomenon, technocapitalism, that is transforming business organizations and the ways in which they transact, produce, and ship their goods. Technocapitalism is an evolution of market capitalism that is rooted in technological innovation and supported by such intangibles as creativity and knowledge. This paper considers first the main characteristics of networks that support the e-economy and its source phenomenon, the emergence of technocapitalism. Networks are thought to be the main vehicle through which the e-economy spreads, and they have major effects on the organization of business firms. The culture of technocapitalism, with its emphasis on continuous innovation and rapid adjustment, is largely behind the rising importance of networks. A second section then considers the deconstruction of business firms and its relation to networks, the e-economy, and the rise of technocapitalism. A historical perspective is provided to show the contrast with previous eras. The deconstruction of business organizations involves a major transformation of the norms and ways in which firms are run and structured. Finally, the likely implications for transportation and shipping of the rise of the e-economy, its networks, and the deconstruction of firms are discussed. The logistics, pricing, and infrastructure of shipping are likely to be substantially affected by the spread of the e-economy, its networks, and the deconstruction of firms. [source] Growth and product quality of European eel (Anguilla anguilla) as affected by dietary protein and lipid sourcesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2003U. Luzzana Summary A 12-week feeding trial was undertaken to evaluate the effects of partial replacement of marine raw materials in the diet with soybean meal and beef tallow on growth and product quality of European eel (Anguilla anguilla). Based on growth, feed efficiency and chemical composition, soybean meal was found to be an unsuitable ingredient for eel diets as a substitute for fishmeal (25% on a protein basis), probably because of the low digestibility of its carbohydrate content. However, beef tallow can be used to replace 50% of fish oil without reduction in growth, provided that digestible carbohydrates are present in the diet. No major effects of protein and lipid sources in the diet were found on fillet chemical composition. Sensory analysis revealed no significant differences between fish fed the control and the experimental diets, with the exception of salty taste which was significantly higher in fish fed combined soybean meal and beef tallow compared with fish fed the control diet. [source] The effect of macromolecular crowding on protein aggregation and amyloid fibril formation,JOURNAL OF MOLECULAR RECOGNITION, Issue 5 2004Larissa A. Munishkina Abstract Macromolecular crowding is expected to have several significant effects on protein aggregation; the major effects will be those due to excluded volume and increased viscosity. In this report we summarize data demonstrating that macromolecular crowding may lead to a dramatic acceleration in the rate of protein aggregation and formation of amyloid fibrils, using the protein ,-synuclein. The aggregation of ,-synuclein has been implicated as a critical factor in development of Parkinson's disease. Various types of polymers, from neutral polyethylene glycols and polysaccharides (Ficolls, dextrans) to inert proteins, are shown to accelerate ,-synuclein fibrillation. The stimulation of fibrillation increases with increasing length of polymer, as well as increasing polymer concentration. At lower polymer concentrations (typically up to ,100,mg/ml) the major effect is ascribed to excluded volume, whereas at higher polymer concentrations evidence of opposing viscosity effects become apparent. Pesticides and metals, which are linked to increased risk of Parkinson's disease by epidemiological studies, are shown to accelerate ,-synuclein fibrillation under conditions of molecular crowding. Copyright © 2004 John Wiley & Sons, Ltd. [source] Dysfunction of the subthalamic nucleus induces behavioral and movement disorders in monkeys,MOVEMENT DISORDERS, Issue 8 2009Carine Karachi MD Abstract High-frequency stimulation of the subthalamic nucleus (STN) in parkinsonian patients is reported to induce psychiatric effects. The likely explanation for these effects is the partitioning of the STN into sensorimotor, associative, and limbic anatomo-functional territories. Thus, a specific neuronal dysfunction of the STN sensorimotor territory could lead to abnormal movements, whereas a dysfunction of the associative or limbic territory could lead to behavioral disturbances. To test this hypothesis, neuronal dysfunction of the STN was induced by microinjections of the GABA agonist muscimol, or antagonist bicucculline, in various parts of the nucleus in three monkeys. Stereotyped behaviors (licking and biting fingers) and/or violent hyperactivity were obtained with bicuculline injected into the anteromedial, associative, and limbic territories, whereas injections of muscimol induced no major effects. Abnormal limb movements (contralateral ballism) were obtained after muscimol or bicuculline injections into the posterolateral, sensorimotor territory. Control injections localized around the STN induced other effects (mainly torticollis), which underlines the specificity of STN injection effects. Our study supports the hypothesis that the anteromedial part of the STN is involved in behavioral control. © 2009 Movement Disorder Society [source] MRI monitoring of focal cerebral ischemia in peroxisome proliferator-activated receptor (PPAR)-deficient miceNMR IN BIOMEDICINE, Issue 3 2007Jean-Baptiste Pialat Abstract Peroxisome proliferator-activated receptors (PPARs) are a potential target for neuroprotection in focal ischemic stroke. These nuclear receptors have major effects in lipid metabolism, but they are also involved in inflammatory processes. Three PPAR isotypes have been identified: ,, , (or ,) and ,. The development of PPAR transgenic mice offers a promising tool for prospective therapeutic studies. This study used MRI to assess the role of PPAR, and PPAR, in the development of stroke. Permanent middle cerebral artery occlusion induced focal ischemia in wild-type, PPAR, -null mice and PPAR, -null mice. T2 -weighted MRI was performed with a 7 T MRI scan on day 0, 1, 3, 7 and 14 to monitor lesion growth in the various genotypes. General Linear Model statistical analysis found a significant difference in lesion volume between wild-type and PPAR-null mice for both , and , isotypes. These data validate high-resolution MRI for monitoring cerebral ischemic lesions, and confirm the neuroprotective role of PPAR, and PPAR, in the brain. Copyright © 2007 John Wiley & Sons, Ltd. [source] Is polaron effect important for resonant Raman scattering in self-assembled quantum dots?PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2005M. I. Vasilevskiy Abstract While the diagonal (or intra-level) interaction of a confined exciton with optical phonons in self-assembled quantum dots (SAQD's) is rather weak, the non-diagonal one can lead to a considerable change of the exciton spectrum and the formation of a polaron. An impact of this effect on resonant inelastic light scattering is studied theoretically. The polaron spectrum is obtained by numerical diagonalisation of the exciton,phonon interaction Hamiltonian in a truncated Hilbert space of the non-interacting excitons and phonons. Based on this spectrum, the probability of the multi-phonon Raman scattering is calculated, which is compared to that obtained within the standard perturbation theory approach (where phonon emission and absorption are irreversible). It is shown that there are two major effects of the polaron formation: (i) the intensity of the two-phonon (2 LO) peak, relative to that of the fundamental 1 LO one is strongly increased and (ii) the resonant behaviour of the 1 LO peak differs considerably from the perturbation theory predictions. With the correct theoretical interpretation, resonant Raman scattering in SAQD's opens the possibility of accessing the (renormalised) exciton spectrum and exciton,phonon coupling constants. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Race and sex differences and contribution of height: A study on bone size in healthy Caucasians and ChineseAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2005Yuan-Yuan Zhang Osteoporosis is characterized by a loss of bone strength, of which bone size (BS) is an important determinant. However, studies on the factors determining BS are relatively few. The present study evaluated the independent effects of height, age, weight, sex, and race on areal BS at the hip and spine, measured by dual-energy X-ray absorptiometry, while focusing on the differential contributions of height to BS across sex, race, and skeletal site. The subjects were aged 40 years or older, including 763 Chinese (384 males and 379 females) from Shanghai, People's Republic of China, and 424 Caucasians (188 males and 236 females) from Omaha, Nebraska. Basically, Caucasians had significantly larger BS than Chinese. After adjusting for height, age, and weight, the Chinese had similar spine BS, but significantly larger intertrochanter BS in both sexes and larger total hip BS in females compared with Caucasians. Males had significantly larger BS than females before and after adjustment in both ethnic groups. The effects of age, weight, and race varied, depending on skeletal site. As expected, height had major effects on BS variation in both sexes and races. Height tended to account for larger BS variation at the spine than at the hip (except for Chinese females), and larger BS variation in Caucasians than in Chinese of the same sex (except for the trochanter in females). We conclude that height is a major predictor for BS, and its contributions vary across sex, race, and skeletal site. Am. J. Hum. Biol. 17:568,575, 2005. © 2005 Wiley-Liss, Inc. [source] Psychologic Treatment for Hypertension Can Be EfficaciousPREVENTIVE CARDIOLOGY, Issue 1 2003Wolfgang Linden PhD The traditional view of psychologic treatments and their efficacy for treating primary hypertension is that they may be of some benefit for borderline hypertension and that they can be potentially useful adjuncts to medical treatment. This review challenges such cautious conclusions by critically analyzing previous reviews and by also considering innovative, newer clinical trials. One reason for cautious conclusions has been selective reviewing and a lack of well-designed trials. Measurement and study protocol differences as well as differences in treatment modality have all been shown to have major effects on observed outcomes. Studies that promise better results have the following characteristics: 1) use of 24-hour ambulatory monitoring as an end point to rule out white coat hypertension that does not need treatment in the first place; 2) inclusion of patients with truly elevated blood pressure at pretreatment; and 3) multicomponent treatments that are tailored to individual patient needs. [source] Automating proteome analysis: improvements in throughput, quality and accuracy of protein identification by peptide mass fingerprinting,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 23 2004Ludovic Canelle The use of robots has major effects on maximizing the proteomic workflow required in an increasing number of high-throughput projects and on increasing the quality of the data. In peptide mass finger printing (PMF), automation of steps downstream of two-dimensional gel electrophoresis is essential. To achieve this goal, the workflow must be fluid. We have developed tools using macros written in Microsoft Excel and Word to complete the automation of our platform. Additionally, because sample preparation is crucial for identification of proteins by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, we optimized a sandwich method usable by any robot for spotting digests on a MALDI target. This procedure enables further efficient automated washing steps directly on the MALDI target. The success rate of PMF identification was evaluated for the automated sandwich method, and for the dried-droplet method implemented on the robot as recommended by the manufacturer. Of the two methods, the sandwich method achieved the highest identification success rate and sequence coverage of proteins. Copyright © 2004 John Wiley & Sons, Ltd. [source] Modelling tropical atmospheric convection in the context of the weak temperature gradient approximationTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 608 2005David J. Raymond Abstract A cumulus ensemble model is used to simulate the interaction between tropical atmospheric convection and the large-scale tropical environment in the context of Sobel and Bretherton's (2000) weak temperature gradient approximation. In this approximation, gravity waves are assumed to redistribute buoyancy anomalies over a broad area of the tropics, thus maintaining the local virtual-temperature profile close to the large-scale mean. This result is implemented in the model by imposing the advective effects of a hypothetical mean vertical velocity which is just sufficient to counteract the local heating induced by convection and radiation. The implied vertical advection in the moisture equation and entrainment of air from the surrounding environment have major effects on the evolution of convection in the model. The precipitation produced by the model mimics the results of a very simple model of tropical precipitation introduced by Raymond (2000), in that the mean rainfall rate predicted by the cumulus ensemble model is, to a good approximation, a function only of the mean column precipitable water. The evolution of the precipitable water, and hence the precipitation rate, is a result of the imbalance between the surface flux of moist entropy into the domain and the radiative loss of entropy out of the top of the domain. This evolution leads to a statistically steady solution in which the resulting precipitation rate is a unique function of the entropy flux imbalance. These results support the hypothesis that tropical precipitation averaged over distance scales of a few hundred kilometres and time scales of a day is a consequence only of local thermodynamic factors. Copyright © 2005 Royal Meteorological Society [source] Can atmospheric input of nitrogen affect seed bank dynamics in habitats of conservation interest?APPLIED VEGETATION SCIENCE, Issue 3 2008The case of dune slacks Abstract. Questions: Does the increased atmospheric deposition of nitrogen, which can have major effects on the established vegetation of nutrient-poor habitats, also impact germination from the soil seed bank? Location: Coastal dune slacks at Newborough Warren, Wales, UK. Methods: The effects of nitrogen addition (15 kg.ha -1.a -1) on seed germination from the soil seed bank were investigated using the seedling emergence method between September 2004 and February 2005. Results: More seedlings emerged from fertilised samples than unfertilised controls. Most species showed enhanced germination after fertilisation with nitrogen, with seedling numbers statistically significantly greater in nitrogen addition samples in a quarter of species abundant enough for analysis. Species that responded positively to fertilisation were species with low Ellenberg indicator values indicative of infertile sites. Conclusions: Most species showed increased germination after fertilisation with nitrogen, including early successional species normally growing in nutrient-poor conditions. This suggests that the increased atmospheric deposition of nitrogen probably not only impacts on established vegetation, but also has the potential to alter seed bank dynamics. [source] SUMOylation and cell signallingBIOTECHNOLOGY JOURNAL, Issue 12 2009Artemisia M. Andreou Abstract SUMOylation is a highly transient post-translational protein modification. Attachment of SUMO to target proteins occurs via a number of specific activating and ligating enzymes that form the SUMO-substrate complex, and other SUMO-specific proteases that cleave the covalent bond, thus leaving both SUMO and target protein free for the next round of modification. SUMO modification has major effects on numerous aspects of substrate function, including subcellular localisation, regulation of their target genes, and interactions with other molecules. The modified SUMO-protein complex is a very transient state, and it thus facilitates rapid response and actions by the cell, when needed. Like phosphorylation, acetylation and ubiquitination, SUMOylation has been associated with a number of cellular processes. In addition to its nuclear role, important sides of mitochondrial activity, stress response signalling and the decision of cells to undergo senescence or apoptosis, have now been shown to involve the SUMO pathway. With ever increasing numbers of reports linking SUMO to human disease, like neurodegeneration and cancer metastasis, it is highly likely that novel and equally important functions of components of the SUMOylation process in cell signalling pathways will be elucidated in the near future. [source] | ||||||||||||||||||||||