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7 result(s) for "Rauschkolb, Robert"
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Recent evolution of flowering time across multiple European plant species correlates with changes in aridity
Ongoing global warming and increasing drought frequencies impact plant populations and potentially drive rapid evolutionary adaptations. Historical comparisons, where plants grown from seeds collected in the past are compared to plants grown from freshly collected seeds from populations of the same sites, are a powerful method to investigate recent evolutionary changes across many taxa. We used 21–38 years old seeds of 13 European plant species, stored in seed banks and originating from Mediterranean and temperate regions, together with recently collected seeds from the same sites for a greenhouse experiment to investigate shifts in flowering phenology as a potential result of adaptive evolution to changes in drought intensities over the last decades. We further used single nucleotide polymorphism (SNP) markers to quantify relatedness and levels of genetic variation. We found that, across species, current populations grew faster and advanced their flowering. These shifts were correlated with changes in aridity at the population origins, suggesting that increased drought induced evolution of earlier flowering, whereas decreased drought lead to weak or inverse shifts in flowering phenology. In five out of the 13 species, however, the SNP markers detected strong differences in genetic variation and relatedness between the past and current populations collected, indicating that other evolutionary processes may have contributed to changes in phenotypes. Our results suggest that changes in aridity may have influenced the evolutionary trajectories of many plant species in different regions of Europe, and that flowering phenology may be one of the key traits that is rapidly evolving.
Evolution of competitive ability and the response to nutrient availability: a resurrection study with the calcareous grassland herb, Leontodon hispidus
Rapid environmental changes across Europe include warmer and increasingly variable temperatures, changes in soil nutrient availability, and pollinator decline. These abiotic and biotic changes can affect natural plant populations and force them to optimize resource use against competitors. To date, the evolution of competitive ability in the context of changes in nutrient availability remains understudied. In this study, we investigated whether the common calcareous grassland herb Leontodon hispidus recently evolved its competitive ability and response to nutrient availability. We compared ancestors sampled in 1995 and descendants sampled in 2018 and applied a competition treatment in combination with weekly nutrient treatments (no fertilizer, nitrogen, phosphorus, and both). We found evidence for evolution of increased competitive ability, with descendants producing more vegetative biomass than ancestors when grown under competition. Furthermore, supplementing nutrients (especially N) reduced differences in competitive ability between ancestors and descendants, suggesting that nutrients are a limiting factor in interspecific competition, which could be linked to the decreasing nitrogen emissions into the atmosphere since the 1990s. Our study demonstrates rapid contemporary evolution of competitive ability, but also the complexity of the underlying processes of contemporary evolution, and sheds light on the importance of understudied potential selection agents such as nutrient availability.
Spatial variability in herbaceous plant phenology is mostly explained by variability in temperature but also by photoperiod and functional traits
Whereas temporal variability of plant phenology in response to climate change has already been well studied, the spatial variability of phenology is not well understood. Given that phenological shifts may affect biotic interactions, there is a need to investigate how the variability in environmental factors relates to the spatial variability in herbaceous species’ phenology by at the same time considering their functional traits to predict their general and species-specific responses to future climate change. In this project, we analysed phenology records of 148 herbaceous species, which were observed for a single year by the PhenObs network in 15 botanical gardens. For each species, we characterised the spatial variability in six different phenological stages across gardens. We used boosted regression trees to link these variabilities in phenology to the variability in environmental parameters (temperature, latitude and local habitat conditions) as well as species traits (seed mass, vegetative height, specific leaf area and temporal niche) hypothesised to be related to phenology variability. We found that spatial variability in the phenology of herbaceous species was mainly driven by the variability in temperature but also photoperiod was an important driving factor for some phenological stages. In addition, we found that early-flowering and less competitive species characterised by small specific leaf area and vegetative height were more variable in their phenology. Our findings contribute to the field of phenology by showing that besides temperature, photoperiod and functional traits are important to be included when spatial variability of herbaceous species is investigated.
Recent evolution of flowering time across multiple European plant species correlates with changes in aridity
Ongoing global warming and increasing drought frequencies impact plant populations and potentially drive rapid evolutionary adaptations. Historical comparisons, where plants grown from seeds collected in the past are compared to plants grown from freshly collected seeds from populations of the same sites, are a powerful method to investigate recent evolutionary changes across many taxa. We used 21-38 year-old seeds of 13 European plant species, stored in seed banks and originating from Mediterranean and temperate regions, together with recently collected seeds from the same sites for a greenhouse experiment to investigate shifts in flowering phenology as a potential result of adaptive evolution to changes in drought intensities over the last decades. We further used single nucleotide polymorphism (SNP) markers to quantify relatedness and levels of genetic variation. We found that, across species, current populations grew faster and advanced their flowering. These shifts were correlated with changes in aridity at the population origins, suggesting that increased drought induced evolution of earlier flowering, whereas decreased drought lead to weak or inverse shifts in flowering phenology. In five out of the 13 species, however, the SNP markers detected strong differences in genetic variation and relatedness between the past and current populations collected, indicating that other evolutionary processes may have contributed to changes in phenotypes. Our results suggest that changes in aridity may have influenced the evolutionary trajectories of many plant species in different regions of Europe, and that flowering phenology may be one of the key traits that is rapidly evolving. We demonstrated that accurately sampled and stored seed collections from conventional seed banks can, with some limitations, be used in a similar way as the increasingly popular resurrection approach sensu stricto. Given the vast availability of seeds stored in seed banks, this opens up a large potential for future research on rapid evolutionary adaptation to changing environmental conditions across a wide variety of taxa suitable for resurrection. Furthermore, this work is unique and novel, as we combine greenhouse experiments with molecular and climatic data to disentangle potential drivers for the observed phenotypic evolution, which, to our knowledge, was never done in resurrection studies.
Garden, greenhouse or climate chamber? Experimental conditions influence whether genetic differences are phenotypically expressed
1. Common-environment experiments are important to study genetically-based phenotypic variation within and among plant populations. Such experiments can be performed in an experimental garden, greenhouse or climate chamber. However, phenotypic expression may be strongly affected by the environmental conditions and influenced by parental and storage effects. Hence, it is unclear if results from common-environment experiments are reproducible across multiple experimental setups. 2. In this study, we assessed the effects of three different growth facilities (outdoor garden, greenhouse, and climate chamber), on phenotypic expression. We compared ancestral and descendant genotypes of the same population of Leontodon hispidus. We also evaluated differences in phenotypic expression between plants grown after one (F1) vs. two (F2) intermediate generations. 3. We observed strong differences among plants growing in different growth facilities. Furthermore, we found that descendants had larger rosettes than ancestors only in the greenhouse and they flowered later than ancestors exclusively in the climate chamber. We did not find significant differences between intermediate generations within the growth facilities. 4. Overall, our study demonstrates that environmental variation among growth facilities can dictate the presence and magnitude of phenotypic differences. This implies that absence of evidence for phenotypic differences is not evidence of absence. Experimental systems should be carefully designed to provide meaningful conditions related to the research question. Finally, growing a second intermediate generation did not impact the genetic differences of ancestors and descendants within the facilities, supporting that only one intermediate generation may be sufficient to reduce detectable parental and storage effects.Competing Interest StatementThe authors have declared no competing interest.
Long-term Safety and Efficacy of Tapentadol Extended Release Following up to 2 Years of Treatment in Patients With Moderate to Severe, Chronic Pain: Results of an Open-label Extension Trial
Tapentadol extended release (ER) has demonstrated efficacy and safety for the management of moderate to severe, chronic pain in adults. This study evaluated the long-term safety and tolerability of tapentadol ER in patients with chronic osteoarthritis or low back pain. Patients were enrolled in this 1-year, open-label extension study after completing one of two 15-week, placebo-controlled studies of tapentadol ER and oxycodone controlled release (CR) for osteoarthritis knee pain (NCT00421928) or low back pain (NCT00449176), a 7-week crossover study between tapentadol immediate release and tapentadol ER for low back pain (NCT00594516), or a 1-year safety study of tapentadol ER and oxycodone CR for osteoarthritis or low back pain (NCT00361504). After titrating the drug to an optimal dose, patients received tapentadol ER (100–250 mg BID) for up to 1 year (after finishing treatment in the preceding studies); patients who were previously treated with tapentadol ER in the 1-year safety study received tapentadol ER continuously for up to 2 years in total. Of the 1,154 patients in the safety population, 82.7% were aged >65 years and 57.9% were female; 50.1% had mild baseline pain intensity. Mean (SD) pain intensity scores (11-point numerical rating scale) were 3.9 (2.38) at baseline (end of preceding study) and 3.7 (2.42) at end point, indicating that pain relief was maintained during the extension study. Improvements in measures of quality of life (eg, EuroQol-5 Dimension and the 36-item Short Form Health Survey [SF-36]) health status questionnaires) achieved during the preceding studies were maintained during the open-label extension study. Tapentadol ER was associated with a safety and tolerability profile comparable to that observed in the preceding studies. The most common treatment-emergent adverse events (incidence ≥10%; n = 1154) were headache (13.1%), nausea (11.8%), and constipation (11.1%). Similar efficacy and tolerability results were shown for patients who received up to 2 years of tapentadol ER treatment. Pain relief and improvements in quality of life achieved during the preceding studies were maintained throughout this extension study, during which tapentadol ER was well tolerated for the long-term treatment of chronic osteoarthritis or low back pain over up to 2 years of treatment. (ClinicalTrials.gov identifier: NCT00487435.)
Alternative Oxidase Attenuates Cigarette Smoke–induced Lung Dysfunction and Tissue Damage
Cigarette smoke (CS) exposure is the predominant risk factor for the development of chronic obstructive pulmonary disease (COPD) and the third leading cause of death worldwide. We aimed to elucidate whether mitochondrial respiratory inhibition and oxidative stress are triggers in its etiology. In different models of CS exposure, we investigated the effect on lung remodeling and cell signaling of restoring mitochondrial respiratory electron flow using alternative oxidase (AOX), which bypasses the cytochrome segment of the respiratory chain. AOX attenuated CS-induced lung tissue destruction and loss of function in mice exposed chronically to CS for 9 months. It preserved the cell viability of isolated mouse embryonic fibroblasts treated with CS condensate, limited the induction of apoptosis, and decreased the production of reactive oxygen species (ROS). In contrast, the early-phase inflammatory response induced by acute CS exposure of mouse lung, i.e., infiltration by macrophages and neutrophils and adverse signaling, was unaffected. The use of AOX allowed us to obtain novel pathomechanistic insights into CS-induced cell damage, mitochondrial ROS production, and lung remodeling. Our findings implicate mitochondrial respiratory inhibition as a key pathogenic mechanism of CS toxicity in the lung. We propose AOX as a novel tool to study CS-related lung remodeling and potentially to counteract CS-induced ROS production and cell damage.