Botanic gardens and climate change: a review of scientific activities at the Royal Botanic Gardens,Kew

In 2009, the Royal Botanic Gardens, Kew (UK) launched its Breathing Planet Programme. This 10 year programme seeks to re-align Kew’s work to develop plant-based solutions to the challenges of climate change. Further to the development of the Programme, Kew has undertaken a review of its science projects with relevance to mitigating the impacts of climate change on plant diversity and people. The review has allowed Kew to better understand its current strengths and weaknesses in this area in order to plan for the future. The findings of the review could be relevant for science programmes in other botanic gardens. Botanic gardens play a fundamental role in the conservation of biodiversity to mitigate climate change impacts. Knowledge and data on plant systematics, distribution and physiology is vital for modelling and monitoring the impacts of climate change, to help to identify plant species and habitats most at risk of losing their wild diversity. Kew’s Millennium Seed Bank Project will safeguard 25% of plant species by 2020, while in situ projects are improving the conservation of threatened habitats. One challenge is to make such activities relevant and useful to other scientists, conservation groups and policy makers working to address climate change. However, botanic gardens must also develop working practices and projects that specifically address the challenges of climate change. Kew and a global network of partners are doing this in a variety of ways, and examples will be presented in this paper.     

Systemic administration of high-molecular weight hyaluronan stimulates wound healing in genetically diabetic mice

Hyaluronic acid (HA), an essential component of the extracellular matrix, is an efficient space filler that maintains hydration, serves as a substrate for assembly of proteoglycans and is involved in wound healing. Although numerous pieces of evidence demonstrate beneficial effects in promoting wound healing in diabetes, a systemic approach has never been tested. We used an incisional wound healing model in genetically diabetic mice to test the effects of systemic injection of HA. Diabetic (n = 56) and normoglycemic (n = 56) mice were subjected to incision and randomized (8 groups of 7 animals each) to receive HA at different doses, 7.5, 15 and 30 mg/kg/i.p., or vehicle (0.9% NaCl solution) for 12 days. At the end of the experiment animals were sacrificed and skin wounds were excised for histological, biochemical and molecular analysis. Histology revealed that the most effective dose to improve wound repair and angiogenesis in diabetic mice was 30 mg/kg. Furthermore HA injection (30 mg/kg) improved the altered healing pattern in diabetic animals, increased skin remodeling proteins TGF-β and transglutaminase-II and restored the altered expression of cyclin B1/Cdc2 complex. Evaluation of skin from diabetic animals injected with HA revealed also an increase in HA content, suggesting that systemic injection may be able to restore the reduced intracellular HA pool of diabetic mice. Finally HA markedly improved skin mechanical properties. These promising results, if confirmed in a clinical setting, may improve the care and management of diabetic patients.     

Habitat complexity drives experimental evolution of a conditionally expressed secondary sexual trait

The conditional expression of alternative phenotypes underlies the production of almost all life history decisions and many dichotomous traits, including male alternative reproductive morphs and behavioral tactics. Changes in tactic fitness should lead to evolutionary shifts in developmental switch points that underlie tactic expression. We used experimental evolution to directly test this hypothesis by rearing ten generations of the male-dimorphic mite Rhizoglyphus echinopus in either simple or three-dimensionally complex habitats that differed in their effects on morph fitness. In R. echinopus, fighter males develop weapons used for killing rivals, whereas scrambler males do not. Populations evolving in complex 3D habitats, where fighters had reduced fitness, produced fewer fighters because the switch point for fighter development evolved to a larger critical body size. Both the reduced mobility of fighter males and the altered spatial distribution of potential mates and rivals in the complex habitat were implicated in the evolutionary divergence of switch point between the habitats. Our results demonstrate how abiotic factors like habitat complexity can have a profound effect on evolution through sexual selection.     

Characterization of the disordered-to-α-helical transition of IA₃ by SDSL-EPR spectroscopy

Electron paramagnetic resonance (EPR) spectroscopy coupled with site-directed spin labeling (SDSL) is a valuable tool for characterizing the mobility and conformational changes of proteins but has seldom been applied to intrinsically disordered proteins (IDPs). Here, IA₃ is used as a model system demonstrating SDSL-EPR characterization of conformational changes in small IDP systems. IA₃ has 68 amino acids, is unstructured in solution, and becomes α-helical upon addition of the secondary structural stabilizer 2,2,2-trifluoroethanol (TFE). Two single cysteine substitutions, one in the N-terminus (S14C) and one in the C-terminus (N58C), were generated and labeled with three different nitroxide spin labels. The resultant EPR line shapes of each of the labels were compared and each reported changes in mobility upon addition of TFE. Specifically, the spectral line shape parameters h₍₊₁₎/h₍₀₎, the local tumbling volume (V_L), and the percent change of the h₍₋₁₎ intensity were utilized to quantitatively monitor TFE-induced conformational changes. The values of h_(+1)/h₍₀₎ as a function of TFE titration varied in a sigmoidal manner and were fit to a two-state Boltzmann model that provided values for the midpoint of the transition, thus, reporting on the global conformational change of IA₃. The other parameters provide site-specific information and show that S14C-SL undergoes a conformational change resulting in more restricted motion than N58C-SL, which is consistent with previously published results obtained by studies using NMR and circular dichroism spectroscopy indicating a higher degree of α-helical propensity of the N-terminal segment of IA₃. Overall, the results provide a framework for data analyzes that can be used to study induced unstructured-to-helical conformations in IDPs by SDSL.     

Phenanthrene Emulsification and Biodegradation Using Rhamnolipid Biosurfactants and Acinetobacter calcoaceticus In Vitro

The ability of biosurfactants and Acinetobacter calcoaceticus to enhance the emulsification and biodegradation of phenanthrene was investigated. Phenanthrene is a polycyclic aromatic hydrocarbon that may be derived from various sources, for example incomplete combustion of petroleum fuel, and thus it occurs ubiquitously throughout the environment. In order to assess the efficacy of a biosurfactant microparticle system, emulsification assays and in vitro biodegradation studies were conducted. Emulsification assays were carried out to assess the stability of phenanthrene emulsions. Emulsion stability was determined by the height of the emulsion layer (Emulsification Index) and turbidity. In vitro biodegradation tests were done to estimate phenanthrene degradation from an aqueous system by A. calcoaceticus supplemented with encapsulated (ERhBS) and nonencapsulated biosurfactants (NERhBS). Results show that phenanthrene emulsifications were stabilized after 48 h with NERhBS and remained stable for 72 additional hours. Phenanthrene emulsifications were stabilized with ERhBS after 216 h and remained stable for an additional 96 h. A. calcoaceticus alone and supplemented with rhamnolipid biosurfactant were able to biodegrade 10 to 50 mg L^?1 of phenanthrene within 250 h. When supplemented with NERhBS, A. calcoaceticus degraded phenanthrene significantly faster than when nonsupplemented or supplemented with ERhBS. Addition of exogenous biosurfactants was considered to be a major factor driving the direct correlation between decreasing phenanthrene concentration in the system and increasing bacterial biomass.     

Functional changes in the snail statocyst system elicited by microgravity

Background

The mollusk statocyst is a mechanosensing organ detecting the animal''s orientation with respect to gravity. This system has clear similarities to its vertebrate counterparts: a weight-lending mass, an epithelial layer containing small supporting cells and the large sensory hair cells, and an output eliciting compensatory body reflexes to perturbations.

Methodology/Principal Findings

In terrestrial gastropod snail we studied the impact of 16- (Foton M-2) and 12-day (Foton M-3) exposure to microgravity in unmanned orbital missions on: (i) the whole animal behavior (Helix lucorum L.), (ii) the statoreceptor responses to tilt in an isolated neural preparation (Helix lucorum L.), and (iii) the differential expression of the Helix pedal peptide (HPep) and the tetrapeptide FMRFamide genes in neural structures (Helix aspersa L.). Experiments were performed 13–42 hours after return to Earth. Latency of body re-orientation to sudden 90° head-down pitch was significantly reduced in postflight snails indicating an enhanced negative gravitaxis response. Statoreceptor responses to tilt in postflight snails were independent of motion direction, in contrast to a directional preference observed in control animals. Positive relation between tilt velocity and firing rate was observed in both control and postflight snails, but the response magnitude was significantly larger in postflight snails indicating an enhanced sensitivity to acceleration. A significant increase in mRNA expression of the gene encoding HPep, a peptide linked to ciliary beating, in statoreceptors was observed in postflight snails; no differential expression of the gene encoding FMRFamide, a possible neurotransmission modulator, was observed.

Conclusions/Significance

Upregulation of statocyst function in snails following microgravity exposure parallels that observed in vertebrates suggesting fundamental principles underlie gravi-sensing and the organism''s ability to adapt to gravity changes. This simple animal model offers the possibility to describe general subcellular mechanisms of nervous system''s response to conditions on Earth and in space.