TY - JOUR A1 - Chen, Pan A1 - Bornhorst, Julia A1 - Aschner, Michael T1 - Manganese metabolism in humans JF - Frontiers in Bioscience-Landmark N2 - Manganese (Mn) is an essential nutrient for intracellular activities; it functions as a cofactor for a variety of enzymes, including arginase, glutamine synthetase (GS), pyruvate carboxylase and Mn superoxide dismutase (Mn-SOD). Through these metalloproteins, Mn plays critically important roles in development, digestion, reproduction, antioxidant defense, energy production, immune response and regulation of neuronal activities. Mn deficiency is rare. In contrast Mn poisoning may be encountered upon overexposure to this metal. Excessive Mn tends to accumulate in the liver, pancreas, bone, kidney and brain, with the latter being the major target of Mn intoxication. Hepatic cirrhosis, polycythemia, hypermanganesemia, dystonia and Parkinsonism-like symptoms have been reported in patients with Mn poisoning. In recent years, Mn has come to the forefront of environmental concerns due to its neurotoxicity. Molecular mechanisms of Mn toxicity include oxidative stress, mitochondrial dysfunction, protein misfolding, endoplasmic reticulum (ER) stress, autophagy dysregulation, apoptosis, and disruption of other metal homeostasis. The mechanisms of Mn homeostasis are not fully understood. Here, we will address recent progress in Mn absorption, distribution and elimination across different tissues, as well as the intracellular regulation of Mn homeostasis in cells. We will conclude with recommendations for future research areas on Mn metabolism. KW - Manganese KW - Metal Metabolism KW - Homeostasis KW - Blood-Brain Barrier KW - Neurotoxicity KW - Transporters KW - Review Y1 - 2018 U6 - https://doi.org/10.2741/4665 SN - 1093-9946 SN - 1093-4715 VL - 23 IS - 9 SP - 1655 EP - 1679 PB - Frontiers in Bioscience INC CY - Irvine ER - TY - JOUR A1 - Braga, Raul Renno A1 - Gomez-Aparicio, Lorena A1 - Heger, Tina A1 - Simoes Vitule, Jean Ricardo A1 - Jeschke, Jonathan M. T1 - Structuring evidence for invasional meltdown BT - broad support but with biases and gaps JF - Biological invasions : unique international journal uniting scientists in the broad field of biological invasions N2 - Negative interactions have been suggested as a major barrier for species arriving in a new habitat. More recently, positive interactions drew attention from community assembly theory and invasion science. The invasional meltdown hypothesis (IMH) introduced the idea that positive interactions among non-native species could facilitate one another’s invasion, even increasing their impact upon the native community. Many studies have addressed IMH, but with contrasting results, reflecting various types of evidence on a multitude of scales. Here we use the hierarchy-of-hypotheses (HoH) approach to differentiate key aspects of IMH, organizing and linking empirical studies to sub-hypotheses of IMH. We also assess the level of empirical support for each sub-hypothesis based on the evidence reported in the studies. We identified 150 studies addressing IMH. The majority of studies support IMH, but the evidence comes from studies with different aims and questions. Supporting studies at the community or ecosystem level are currently rare. Evidence is scarce for marine habitats and vertebrates. Few sub-hypotheses are questioned by more than 50% of the evaluated studies, indicating that non-native species do not affect each other’s survival, growth, reproduction, abundance, density or biomass in reciprocal A ↔ B interactions. With the HoH for IMH presented here, we can monitor progress in empirical tests and evidences of IMH. For instance, more tests at the community and ecosystem level are needed, as these are necessary to address the core of this hypothesis. KW - Facilitation KW - Mutualism KW - Review KW - Nonindigenous KW - Exotic Y1 - 2018 U6 - https://doi.org/10.1007/s10530-017-1582-2 SN - 1387-3547 SN - 1573-1464 VL - 20 IS - 4 SP - 923 EP - 936 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Ayllon, Daniel A1 - Grimm, Volker A1 - Attinger, Sabine A1 - Hauhs, Michael A1 - Simmer, Clemens A1 - Vereecken, Harry A1 - Lischeid, Gunnar T1 - Cross-disciplinary links in environmental systems science BT - Current state and claimed needs identified in a meta-review of process models JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - Terrestrial environmental systems are characterised by numerous feedback links between their different compartments. However, scientific research is organized into disciplines that focus on processes within the respective compartments rather than on interdisciplinary links. Major feedback mechanisms between compartments might therefore have been systematically overlooked so far. Without identifying these gaps, initiatives on future comprehensive environmental monitoring schemes and experimental platforms might fail. We performed a comprehensive overview of feedbacks between compartments currently represented in environmental sciences and explores to what degree missing links have already been acknowledged in the literature. We focused on process models as they can be regarded as repositories of scientific knowledge that compile findings of numerous single studies. In total, 118 simulation models from 23 model types were analysed. Missing processes linking different environmental compartments were identified based on a meta-review of 346 published reviews, model inter-comparison studies, and model descriptions. Eight disciplines of environmental sciences were considered and 396 linking processes were identified and ascribed to the physical, chemical or biological domain. There were significant differences between model types and scientific disciplines regarding implemented interdisciplinary links. The most wide-spread interdisciplinary links were between physical processes in meteorology, hydrology and soil science that drive or set the boundary conditions for other processes (e.g., ecological processes). In contrast, most chemical and biological processes were restricted to links within the same compartment. Integration of multiple environmental compartments and interdisciplinary knowledge was scarce in most model types. There was a strong bias of suggested future research foci and model extensions towards reinforcing existing interdisciplinary knowledge rather than to open up new interdisciplinary pathways. No clear pattern across disciplines exists with respect to suggested future research efforts. There is no evidence that environmental research would clearly converge towards more integrated approaches or towards an overarching environmental systems theory. (c) 2017 Elsevier B.V. All rights reserved. KW - Review KW - Interdisciplinary links KW - Integrated environmental modelling KW - Research needs Y1 - 2018 U6 - https://doi.org/10.1016/j.scitotenv.2017.12.007 SN - 0048-9697 SN - 1879-1026 VL - 622 SP - 954 EP - 973 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Van Donk, Ellen A1 - Ianora, Adrianna A1 - Vos, Matthijs T1 - Induced defences in marine and freshwater phytoplankton a review JF - Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica N2 - Many organisms have developed defences to avoid predation by species at higher trophic levels. The capability of primary producers to defend themselves against herbivores affects their own survival, can modulate the strength of trophic cascades and changes rates of competitive exclusion in aquatic communities. Algal species are highly flexible in their morphology, growth form, biochemical composition and production of toxic and deterrent compounds. Several of these variable traits in phytoplankton have been interpreted as defence mechanisms against grazing. Zooplankton feed with differing success on various phytoplankton species, depending primarily on size, shape, cell wall structure and the production of toxins and deterrents. Chemical cues associated with (i) mechanical damage, (ii) herbivore presence and (iii) grazing are the main factors triggering induced defences in both marine and freshwater phytoplankton, but most studies have failed to disentangle the exact mechanism(s) governing defence induction in any particular species. Induced defences in phytoplankton include changes in morphology (e.g. the formation of spines, colonies and thicker cell walls), biochemistry (such as production of toxins, repellents) and in life history characteristics (formation of cysts, reduced recruitment rate). Our categorization of inducible defences in terms of the responsible induction mechanism provides guidance for future work, as hardly any of the available studies on marine or freshwater plankton have performed all the treatments that are required to pinpoint the actual cue(s) for induction. We discuss the ecology of inducible defences in marine and freshwater phytoplankton with a special focus on the mechanisms of induction, the types of defences, their costs and benefits, and their consequences at the community level. KW - Defenses KW - Algae KW - Review KW - Plankton community KW - Cyanobacteria KW - Toxins Y1 - 2011 U6 - https://doi.org/10.1007/s10750-010-0395-4 SN - 0018-8158 SN - 1573-5117 VL - 668 IS - 1 SP - 3 EP - 19 PB - Springer CY - Dordrecht ER -