A data-driven approach to multiple-stressor impact assessment for a marine protected area.

The coastal environment is not managed in a way that considers the impact of cumulative threats, despite being subject to threats from all realms (marine, land, and atmosphere). Relationships between threats and species are often nonlinear; thus, current (linear) approaches to estimating the impact of threats may be misleading. We developed a data-driven approach to assessing cumulative impacts on ecosystems and applied it to explore nonlinear relationships between threats and a temperate reef fish community. We used data on water quality, commercial fishing, climate change, and indicators of recreational fishing and urbanization to build a cumulative threat map of the northern region in New South Wales, Australia. We used statistical models of fish abundance to quantify associations among threats and biophysical covariates and predicted where cumulative impacts are likely to have the greatest impact on fish. We also assessed the performance of no-take zones (NTZs), to protect fish from cumulative threats across 2 marine protected area networks (marine parks). Fishing had a greater impact on fish than water quality threats (i.e., percent increase above the mean for invertivores was 337% when fishing was removed and was 11% above the mean when water quality was removed inside NTZs), and fishing outside NTZs affected fish abundances inside NTZs. Quantifying the spatial influence of multiple threats enables managers to understand the multitude of management actions required to address threats.

Una estrategia basada en datos para la evaluación de impacto de múltiples estresores en un área marina protegida Resumen Los ambientes costeros no se manejan de manera que se considere el impacto de las amenazas acumulativas, a pesar de que se enfrentan a amenazas de todos los entornos (marinas, terrestres y atmosféricas). Las relaciones entre las amenazas y las especies casi siempre son no lineales; por lo tanto, las estrategias actuales (lineales) para estimar el impacto de las amenazas pueden ser engañosas. Desarrollamos una estrategia basada en datos para evaluar el impacto acumulativo sobre los ecosistemas y la aplicamos para explorar las relaciones no lineales entre las amenazas y la comunidad de peces de arrecifes templados. Usamos datos de la calidad del agua, pesca comercial, cambio climático e indicadores de pesca recreativa y urbanización para construir un mapa acumulativo de amenazas de la región norte de Nueva Gales del Sur, Australia. Usamos modelos estadísticos de la abundancia de peces para cuantificar las asociaciones entre las amenazas y las covarianzas biofísicas y pronosticamos en dónde es probable que los impactos acumulativos sean mayores sobre los peces. También evaluamos el desempeño de las zonas de veda para así proteger a los peces de las amenazas acumulativas en dos redes de áreas marinas protegidas (parques marinos). La pesca tuvo un mayor impacto que la calidad del agua sobre los peces (es decir, el incremento del porcentaje por encima de la media de depredadores de invertebrados fue de 337% cuando se eliminó la pesca y fue de 11% por encima de la media cuando se eliminó la calidad del agua dentro de las zonas de veda) y la pesca fuera de las zonas de veda afectó la abundancia de los peces dentro de ellas. La cuantificación de la influencia espacial de las múltiples amenazas permite que los gestores entiendan la multitud de acciones de manejo que se requieren para abordar las amenazas.

Integrating socioeconomic and ecological data into restoration practice.

Driven by the United Nations Decade on Restoration and international funding initiatives, such as the Mangrove Breakthrough, investment in mangrove restoration is expected to increase. Yet, mangrove restoration efforts frequently fail, usually because of ad hoc site-selection processes that do not consider mangrove ecology and the socioeconomic context. Using decision analysis, we developed an approach that accounts for socioeconomic and ecological data to identify sites with the highest likelihood of mangrove restoration success. We applied our approach in the Biosphere Reserve Marismas Nacionales Nayarit, Mexico, an area that recently received funding for implementing mangrove restoration actions. We identified 468 potential restoration sites, assessed their restorability potential based on socioeconomic and ecological metrics, and ranked sites for implementation with spatial optimization. The metrics we used included favorable conditions for propagules to establish and survive under sea-level rise, provision of ecosystem services, and community dynamics. Sites that were selected based on socioeconomic or ecological metrics alone had lower likelihood of mangrove restoration success than sites that were selected based on integrated socioeconomic and ecological metrics. For example, selecting sites based on only socioeconomic metrics captured 16% of the maximum attainable value of functioning mangroves able to provide propagules to potential restoration sites, whereas selecting sites based on ecological and socioeconomic metrics captured 46% of functioning mangroves. Our approach was developed as part of a collaboration between nongovernmental organizations, local government, and academics under rapid delivery time lines given preexisting mangrove restoration implementation commitments. The systematic decision process we used integrated socioeconomic and ecological considerations even under short delivery deadlines, and our approach can be adapted to help mangrove restoration site-selection decisions elsewhere.

Integración de datos socioeconómicos y ecológicos en las prácticas de restauración Resumen Se espera que la inversión en la restauración de los manglares incremente debido a la Década de Restauración de las Naciones Unidad y las iniciativas internacionales de financiamiento, como The Mangrove Breakthrough. Sin embargo, los esfuerzos de restauración de manglares fallan con frecuencia, generalmente por los procesos de selección de sitios ad­hoc que no consideran la ecología del manglar y el contexto socioeconómico. Usamos el análisis de decisiones para desarrollar una estrategia que considera los datos socioeconómicos y ecológicos para identificar los sitios con mayor probabilidad de éxito de restauración. Aplicamos nuestra estrategia en la Reserva de la Biósfera Marismas Nacionales Nayarit, México, un área que recibió financiamiento reciente para la restauración del manglar. Identificamos 468 sitios potencialmente restaurables, evaluamos su potencial de restauración con base en medidas ecológicas y socioeconómicas y clasificamos los sitios para la implementación con la optimización espacial. Las medidas que usamos incluían las condiciones favorables para que los propágulos se establezcan y sobrevivan con el incremento en el nivel del mar, el suministro de servicios ambientales y las dinámicas de la comunidad. Los sitios seleccionados sólo con base en las medidas ecológicas o socioeconómicas tuvieron una menor probabilidad de éxito de restauración que los sitios que se seleccionaron con base en medidas socioeconómicas y ecológicas integradas. Por ejemplo, la selección de sitios con base sólo en las medidas socioeconómicas capturó el 16% del máximo valor alcanzable de manglares funcionales capaces de proporcionar propágulos a los sitios potenciales de restauración, mientras que la selección basada en medidas ecológicas y socioeconómicas capturó el 46% de los manglares funcionales. Desarrollamos nuestra estrategia como parte de una colaboración entre organizaciones no gubernamentales, el gobierno local y académicos sujetos a una fecha pronta de entrega debido a los compromisos preexistentes para la restauración de manglares. El proceso de decisión sistemática que usamos integró las consideraciones ecológicas y socioeconómicas incluso con plazos cortos de entrega. Nuestra estrategia puede adaptarse para apoyar en la selección de sitios de restauración de manglares en otros sitios.

Ecosystem restructuring along the Great Barrier Reef following mass coral bleaching.

Global warming is markedly changing diverse coral reef ecosystems through an increasing frequency and magnitude of mass bleaching events1-3. How local impacts scale up across affected regions depends on numerous factors, including patchiness in coral mortality, metabolic effects of extreme temperatures on populations of reef-dwelling species4 and interactions between taxa. Here we use data from before and after the 2016 mass bleaching event to evaluate ecological changes in corals, algae, fishes and mobile invertebrates at 186 sites along the full latitudinal span of the Great Barrier Reef and western Coral Sea. One year after the bleaching event, reductions in live coral cover of up to 51% were observed on surveyed reefs that experienced extreme temperatures; however, regional patterns of coral mortality were patchy. Consistent declines in coral-feeding fishes were evident at the most heavily affected reefs, whereas few other short-term responses of reef fishes and invertebrates could be attributed directly to changes in coral cover. Nevertheless, substantial region-wide ecological changes occurred that were mostly independent of coral loss, and instead appeared to be linked directly to sea temperatures. Community-wide trophic restructuring was evident, with weakening of strong pre-existing latitudinal gradients in the diversity of fishes, invertebrates and their functional groups. In particular, fishes that scrape algae from reef surfaces, which are considered to be important for recovery after bleaching2, declined on northern reefs, whereas other herbivorous groups increased on southern reefs. The full impact of the 2016 bleaching event may not be realized until dead corals erode during the next decade5,6. However, our short-term observations suggest that the recovery processes, and the ultimate scale of impact, are affected by functional changes in communities, which in turn depend on the thermal affinities of local reef-associated fauna. Such changes will vary geographically, and may be particularly acute at locations where many fishes and invertebrates are close to their thermal distribution limits7.

Anthropogenic pressures and life history predict trajectories of seagrass meadow extent at a global scale.

Seagrass meadows are threatened by multiple pressures, jeopardizing the many benefits they provide to humanity and biodiversity, including climate regulation and food provision through fisheries production. Conservation of seagrass requires identification of the main pressures contributing to loss and the regions most at risk of ongoing loss. Here, we model trajectories of seagrass change at the global scale and show they are related to multiple anthropogenic pressures but that trajectories vary widely with seagrass life-history strategies. Rapidly declining trajectories of seagrass meadow extent (>25% loss from 2000 to 2010) were most strongly associated with high pressures from destructive demersal fishing and poor water quality. Conversely, seagrass meadow extent was more likely to be increasing when these two pressures were low. Meadows dominated by seagrasses with persistent life-history strategies tended to have slowly changing or stable trajectories, while those with opportunistic species were more variable, with a higher probability of either rapidly declining or rapidly increasing. Global predictions of regions most at risk for decline show high-risk areas in Europe, North America, Japan, and southeast Asia, including places where comprehensive long-term monitoring data are lacking. Our results highlight where seagrass loss may be occurring unnoticed and where urgent conservation interventions are required to reverse loss and sustain their essential services.

bioPROTACs as versatile modulators of intracellular therapeutic targets including proliferating cell nuclear antigen (PCNA).

Targeted degradation approaches such as proteolysis targeting chimeras (PROTACs) offer new ways to address disease through tackling challenging targets and with greater potency, efficacy, and specificity over traditional approaches. However, identification of high-affinity ligands to serve as PROTAC starting points remains challenging. As a complementary approach, we describe a class of molecules termed biological PROTACs (bioPROTACs)-engineered intracellular proteins consisting of a target-binding domain directly fused to an E3 ubiquitin ligase. Using GFP-tagged proteins as model substrates, we show that there is considerable flexibility in both the choice of substrate binders (binding positions, scaffold-class) and the E3 ligases. We then identified a highly effective bioPROTAC against an oncology target, proliferating cell nuclear antigen (PCNA) to elicit rapid and robust PCNA degradation and associated effects on DNA synthesis and cell cycle progression. Overall, bioPROTACs are powerful tools for interrogating degradation approaches, target biology, and potentially for making therapeutic impacts.

Fluctuating fortunes: Stressor synchronicity and fluctuating intensity influence biological impacts.

Ecosystems remain under enormous pressure from multiple anthropogenic stressors. Manipulative experiments evaluating stressor interactions and impacts mostly apply stressors under static conditions without considering how variable stressor intensity (i.e. fluctuations) and synchronicity (i.e. timing of fluctuations) affect biological responses. We ask how variable stressor intensity and synchronicity, and interaction type, can influence how multiple stressors affect seagrass. At the highest intensities, fluctuating stressors applied asynchronously reduced seagrass biomass 36% more than for static stressors, yet no such difference occurred for photosynthetic capacity. Testing three separate hypotheses to predict underlying drivers of differences in biological responses highlighted alternative modes of action dependent on how stressors fluctuated over time. Given that environmental conditions are constantly changing, assessing static stressors may lead to inaccurate predictions of cumulative effects. Translating multiple stressor experiments to the real world, therefore, requires considering variability in stressor intensity and the synchronicity of fluctuations.

Interactive effects of multiple stressors vary with consumer interactions, stressor dynamics and magnitude.

Predicting the impacts of multiple stressors is important for informing ecosystem management but is impeded by a lack of a general framework for predicting whether stressors interact synergistically, additively or antagonistically. Here, we use process-based models to study how interactions generalise across three levels of biological organisation (physiological, population and consumer-resource) for a two-stressor experiment on a seagrass model system. We found that the same underlying processes could result in synergistic, additive or antagonistic interactions, with interaction type depending on initial conditions, experiment duration, stressor dynamics and consumer presence. Our results help explain why meta-analyses of multiple stressor experimental results have struggled to identify predictors of consistently non-additive interactions in the natural environment. Experiments run over extended temporal scales, with treatments across gradients of stressor magnitude, are needed to identify the processes that underpin how stressors interact and provide useful predictions to management.

Interactions among multiple stressors vary with exposure duration and biological response.

Coastal ecosystems are exposed to multiple anthropogenic stressors. Effective management actions would be better informed from generalized predictions of the individual, combined and interactive effects of multiple stressors; however, few generalities are shared across different meta-analyses. Using an experimental study, we present an approach for analysing regression-based designs with generalized additive models that allowed us to capture nonlinear effects of exposure duration and stressor intensity and access interactions among stressors. We tested the approach on a globally distributed marine diatom, using 72 h photosynthesis and growth assays to quantify the individual and combined effects of three common water quality stressors; photosystem II-inhibiting herbicide exposure, dissolved inorganic nitrogen (DIN) enrichment and reduced light (due to excess suspended sediment). Exposure to DIN and reduced light generally resulted in additivity, while exposure to diuron and reduced light resulted in additive, antagonistic or synergistic interactions, depending on the stressor intensity, exposure period and biological response. We thus find the context of experimental studies to be a primary driver of interactions. The experimental and modelling approaches used here bridge the gap between two-way designs and regression-based studies, which provides a way forward to identify generalities in multiple stressor interactions.

Greater Consideration of Animals Will Enhance Coastal Restoration Outcomes.

As efforts to restore coastal habitats accelerate, it is critical that investments are targeted to most effectively mitigate and reverse habitat loss and its impacts on biodiversity. One likely but largely overlooked impediment to effective restoration of habitat-forming organisms is failing to explicitly consider non-habitat-forming animals in restoration planning, implementation, and monitoring. These animals can greatly enhance or degrade ecosystem function, persistence, and resilience. Bivalves, for instance, can reduce sulfide stress in seagrass habitats and increase drought tolerance of saltmarsh vegetation, whereas megaherbivores can detrimentally overgraze seagrass or improve seagrass seed germination, depending on the context. Therefore, understanding when, why, and how to directly manipulate or support animals can enhance coastal restoration outcomes. In support of this expanded restoration approach, we provide a conceptual framework, incorporating lessons from structured decision-making, and describe potential actions that could lead to better restoration outcomes using case studies to illustrate practical approaches.

Molecular descriptors suggest stapling as a strategy for optimizing membrane permeability of cyclic peptides.

Cyclic peptides represent a promising class of drug candidates. A significant obstacle limiting their development as therapeutics is the lack of an ability to predict their membrane permeability. We use molecular dynamics simulations to assess the ability of a set of widely used parameters in describing the membrane permeability of a set of model cyclic peptides; the parameters include polar surface area (PSA), the number of hydrogen bonds, and transfer free energy between an aqueous phase and a membrane mimicking phase. These parameters were found to generally correlate with the membrane permeability of the set of cyclic peptides. We propose two new descriptors, the charge reweighted PSA and the non-polar surface area to PSA ratio; both show enhanced correlation with membrane permeability. This inspired us to explore crosslinking of the peptide to reduce the accessible surface area of the backbone polar atoms, and we find that this can indeed result in reductions in the accessible PSA. This gives reason to speculate that crosslinking may result in increased permeability, thus suggesting a new scaffold for the development of cyclic peptides as potential therapeutics.

Directed co-evolution of interacting protein-peptide pairs by compartmentalized two-hybrid replication (C2HR).

Directed evolution methodologies benefit from read-outs quantitatively linking genotype to phenotype. We therefore devised a method that couples protein-peptide interactions to the dynamic read-out provided by an engineered DNA polymerase. Fusion of a processivity clamp protein to a thermostable nucleic acid polymerase enables polymerase activity and DNA amplification in otherwise prohibitive high-salt buffers. Here, we recapitulate this phenotype by indirectly coupling the Sso7d processivity clamp to Taq DNA polymerase via respective fusion to a high affinity and thermostable interacting protein-peptide pair. Escherichia coli cells co-expressing protein-peptide pairs can directly be used in polymerase chain reactions to determine relative interaction strengths by the measurement of amplicon yields. Conditional polymerase activity is further used to link genotype to phenotype of interacting protein-peptide pairs co-expressed in E. coli using the compartmentalized self-replication directed evolution platform. We validate this approach, termed compartmentalized two-hybrid replication, by selecting for high-affinity peptides that bind two model protein partners: SpyCatcher and the large fragment of NanoLuc luciferase. We further demonstrate directed co-evolution by randomizing both protein and peptide components of the SpyCatcher-SpyTag pair and co-selecting for functionally interacting variants.

Individual and combined effects of diuron and light reduction on marine microalgae.

Coastal ecosystems such as those in the Great Barrier Reef (GBR) lagoon, are exposed to stressors in flood plumes including low light (caused by increased turbidity) and agricultural pesticides. Photosystem II (PSII)-inhibiting herbicides are the most frequently detected pesticides in the GBR lagoon, but it is not clear how their toxicity to phototrophic species depends on light availability. This study investigated the individual and combined effects of PSII-inhibiting herbicide, diuron, and reduced light intensity (as a proxy for increased turbidity) on the marine diatom, Phaeodactylum tricornutum. Effective quantum yield (EQY) and cell density were measured to calculate responses relative to the controls over 72-h, in tests with varying stressor intensities. Individually, diuron concentrations (0.1-3 µg l-1) were not high enough to significantly reduce growth (cell density), but led to decreased EQY; while, low light generally led to increased EQY, but only reduced growth at the lowest tested light intensity (5 µmol photons m-2 s-1) after 48-hours. P. tricornutum was less affected by diuron when combined with low light scenarios, with increased EQY (up to 163% of the controls) that was likely due to increased electron transport per photon, despite lesser available photons at this low light intensity. In contrast, growth was completely inhibited relative to the controls when algae were simultaneously exposed to the highest stressor levels (3 µg l-1 diuron and 5 µmol photons m-2 s-1). This study highlights the importance of measuring more than one biological response variable to capture the combined effects of multiple stressors. Management of water quality stressors should consider combined impacts rather than just the impacts of individual stressors alone. Reducing suspended sediment and diuron concentrations in marine waters can decrease harmful effects and bring synergistic benefits to water quality.

Thermal Analysis of a Mixture of Ribosomal Proteins by vT-ESI-MS: Toward a Parallel Approach for Characterizing the Stabilitome.

The thermal stabilities of endogenous, intact proteins and protein assemblies in complex mixtures were characterized in parallel by means of variable-temperature electrospray ionization coupled to mass spectrometry (vT-ESI-MS). The method is demonstrated by directly measuring the melting transitions of seven proteins from a mixture of proteins derived from ribosomes. A proof-of-concept measurement of a fraction of an Escherichia coli lysate is provided to extend this approach to characterize the thermal stability of a proteome. As the solution temperature is increased, proteins and protein complexes undergo structural and organizational transitions; for each species, the folded ↔ unfolded and assembled ↔ disassembled populations are monitored based on changes in vT-ESI-MS charge state distributions and masses. The robustness of the approach illustrates a step toward the proteome-wide characterization of thermal stabilities and structural transitions-the stabilitome.

Direct and indirect effects of heatwaves on a coral reef fishery.

Marine heatwaves are increasing in frequency and intensity, and indirectly impacting coral reef fisheries through bleaching-induced degradation of live coral habitats. Marine heatwaves also affect fish metabolism and catchability, but such direct effects of elevated temperatures on reef fisheries are largely unknown. We investigated direct and indirect effects of the devastating 2016 marine heatwave on the largest reef fishery operating along the Great Barrier Reef (GBR). We used a combination of fishery-independent underwater census data on coral trout biomass (Plectropomus and Variola spp.) and catch-per-unit-effort (CPUE) data from the commercial fishery to evaluate changes in the fishery resulting from the 2016 heatwave. The heatwave caused widespread, yet locally patchy, declines in coral cover, but we observed little effect of local coral loss on coral trout biomass. Instead, a pattern of decreasing biomass at northern sites and stable or increasing biomass at southern sites suggested a direct response of populations to the heatwave. Analysis of the fishery-independent data and CPUE found that in-water coral trout biomass estimates were positively related to CPUE, and that coral trout catch rates increased with warmer temperatures. Temperature effects on catch rates were consistent with the thermal affinities of the multiple species contributing to this fishery. Scaling-up the effect of temperature on coral trout catch rates across the region suggests that GBR-wide catches were 18% higher for a given level of effort during the heatwave year relative to catch rates under the mean temperatures in the preceding 6 years. These results highlight a potentially large effect of heatwaves on catch rates of reef fishes, independent of changes in reef habitats, that can add substantial uncertainty to estimates of stock trends inferred from fishery-dependent (CPUE) data. Overestimation of CPUE could initiate declines in reef fisheries that are currently fully exploited, and threaten sustainable management of reef stocks.

Long-term declines and recovery of meadow area across the world's seagrass bioregions.

As human impacts increase in coastal regions, there is concern that critical habitats that provide the foundation of entire ecosystems are in decline. Seagrass meadows face growing threats such as poor water quality and coastal development. To determine the status of seagrass meadows over time, we reconstructed time series of meadow area from 175 studies that surveyed 547 sites around the world. We found an overall trajectory of decline in all seven bioregions with a global net loss of 5602 km2 (19.1% of surveyed meadow area) occurring since 1880. Declines have typically been non-linear, with rapid and historical losses observed in several bioregions. The greatest net losses of area occurred in four bioregions (Tropical Atlantic, Temperate North Atlantic East, Temperate Southern Oceans and Tropical Indo-Pacific), with declining trends being the slowest and most consistent in the latter two bioregions. In some bioregions, trends have recently stabilised or reversed. Losses, however, still outweigh gains. Despite consistent global declines, meadows show high variability in trajectories, within and across bioregions, highlighting the importance of local context. Studies identified 12 different drivers of meadow area change, with coastal development and water quality as the most commonly cited. Overall, however, attributions were primarily descriptive and only 10% of studies used inferential attributions. Although ours is the most comprehensive dataset to date, it still represents only one-tenth of known global seagrass extent, with conspicuous historical and geographic biases in sampling. It therefore remains unclear whether the bioregional patterns of change documented here reflect changes in the world's unmonitored seagrass meadows. The variability in seagrass meadow trajectories, and the attribution of change to numerous drivers, suggest we urgently need to improve understanding of the causes of seagrass meadow loss if we are to improve local-scale management.

Future carbon emissions from global mangrove forest loss.

Mangroves have among the highest carbon densities of any tropical forest. These 'blue carbon' ecosystems can store large amounts of carbon for long periods, and their protection reduces greenhouse gas emissions and supports climate change mitigation. Incorporating mangroves into Nationally Determined Contributions to the Paris Agreement and their valuation on carbon markets requires predicting how the management of different land-uses can prevent future greenhouse gas emissions and increase CO2 sequestration. We integrated comprehensive global datasets for carbon stocks, mangrove distribution, deforestation rates, and land-use change drivers into a predictive model of mangrove carbon emissions. We project emissions and foregone soil carbon sequestration potential under 'business as usual' rates of mangrove loss. Emissions from mangrove loss could reach 2391 Tg CO2 eq by the end of the century, or 3392 Tg CO2 eq when considering foregone soil carbon sequestration. The highest emissions were predicted in southeast and south Asia (West Coral Triangle, Sunda Shelf, and the Bay of Bengal) due to conversion to aquaculture or agriculture, followed by the Caribbean (Tropical Northwest Atlantic) due to clearing and erosion, and the Andaman coast (West Myanmar) and north Brazil due to erosion. Together, these six regions accounted for 90% of the total potential CO2 eq future emissions. Mangrove loss has been slowing, and global emissions could be more than halved if reduced loss rates remain in the future. Notably, the location of global emission hotspots was consistent with every dataset used to calculate deforestation rates or with alternative assumptions about carbon storage and emissions. Our results indicate the regions in need of policy actions to address emissions arising from mangrove loss and the drivers that could be managed to prevent them.

Glycoproteomic Analysis of Human Urinary Exosomes.

Exosomes represent a class of secreted biological vesicles, which have recently gained attention due to their function as intertissue and interorganism transporters of genetic materials, small molecules, lipids, and proteins. Although the protein constituents of these exosomes are often glycosylated, a large-scale characterization of the glycoproteome has not yet been completed. This study identified 3144 unique glycosylation events belonging to 378 glycoproteins and 604 unique protein sites of glycosylation. With these data, we investigated the level of glycan microheterogeneity within the urinary exosomes, finding on average 5.9 glycans per site. The glycan family abundance on individual proteins showed subtle differences, providing an additional level of molecular characterization compared to the unmodified proteome. Finally, we show protein site-specific changes in regard to the common urinary glycoprotein, uromodulin. While uromodulin is an individual case, these same site-specific analyses provide a way forward for developing diagnostic glycoprotein biomarkers with urine as a noninvasive biological fluid. This study represents an important first step in understanding the functional urinary glycoproteome.

Melting of Hemoglobin in Native Solutions as measured by IMS-MS.

Thermally induced structural transitions of the quaternary structure of the hemoglobin tetramer (human) in aqueous solution (150 mM ammonium acetate) were investigated using a variable temperature electrospray ionization (vt-ESI) technique in combination with ion mobility spectrometry (IMS) and mass spectrometry (MS) measurements. At low solution temperatures (28 to ∼40 °C), a heterotetrameric (α2ß2) complex is the most abundant species that is observed. When the solution temperature is increased, this assembly dissociates into heterodimers (holo αß forms) before ultimately forming insoluble aggregates at higher temperatures (>60 °C). In addition to the holo αß forms, a small population of αß dimers containing only a single heme ligand and having a dioxidation modification mapping to the ß subunit are observed. The oxidized heterodimers are less stable than the unmodified holo-heterodimer. The Cys93 residue of the ß subunit is the primary site of dioxidation. The close proximity of this post translational modification to both the αß subunit interface and the heme binding site suggests that this modification is coupled to the loss of the heme and decreased protein stability. Changes in the charge state and collision cross sections of these species indicate that the tetramers and dimers favor less compact structures at elevated temperatures (prior to temperatures where dissociation dominates).

Synthesis of Chiral Alkenyl Cyclopropane Amino Acids for Incorporation into Stapled Peptides.

α,α'-Disubstituted amino acids serve as important non-proteinogenic amino acids in the construction of stabilized helical peptides. To expand the repertoire of α,α'-disubstituted amino acids, chiral alkenyl-containing cyclopropane amino acids were synthesized via a two-step olefination and cyclopropanation procedure. Herein, we report the first example of the use of alkenyl cyclopropane building blocks to constrain MDM2-targeting helical peptides. The increased potency and efficacy associated with C-terminal cyclopropane substitution is postulated to be driven by a combined effect of net hydrophobicity and enhanced protein association rates.

Geographical limits to species-range shifts are suggested by climate velocity.

The reorganization of patterns of species diversity driven by anthropogenic climate change, and the consequences for humans, are not yet fully understood or appreciated. Nevertheless, changes in climate conditions are useful for predicting shifts in species distributions at global and local scales. Here we use the velocity of climate change to derive spatial trajectories for climatic niches from 1960 to 2009 (ref. 7) and from 2006 to 2100, and use the properties of these trajectories to infer changes in species distributions. Coastlines act as barriers and locally cooler areas act as attractors for trajectories, creating source and sink areas for local climatic conditions. Climate source areas indicate where locally novel conditions are not connected to areas where similar climates previously occurred, and are thereby inaccessible to climate migrants tracking isotherms: 16% of global surface area for 1960 to 2009, and 34% of ocean for the 'business as usual' climate scenario (representative concentration pathway (RCP) 8.5) representing continued use of fossil fuels without mitigation. Climate sink areas are where climate conditions locally disappear, potentially blocking the movement of climate migrants. Sink areas comprise 1.0% of ocean area and 3.6% of land and are prevalent on coasts and high ground. Using this approach to infer shifts in species distributions gives global and regional maps of the expected direction and rate of shifts of climate migrants, and suggests areas of potential loss of species richness.