Incorporating climate change into ecosystem service assessments and decisions: a review

Climate change is having a significant impact on ecosystem services and is likely to become increasingly important as this phenomenon intensifies. Future impacts can be difficult to assess as they often involve long timescales, dynamic systems with high uncertainties, and are typically confounded by other drivers of change. Despite a growing literature on climate change impacts on ecosystem services, no quantitative syntheses exist. Hence, we lack an overarching understanding of the impacts of climate change, how they are being assessed, and the extent to which other drivers, uncertainties, and decision making are incorporated. To address this, we systematically reviewed the peer‐reviewed literature that assesses climate change impacts on ecosystem services at subglobal scales. We found that the impact of climate change on most types of services was predominantly negative (59% negative, 24% mixed, 4% neutral, 13% positive), but varied across services, drivers, and assessment methods. Although uncertainty was usually incorporated, there were substantial gaps in the sources of uncertainty included, along with the methods used to incorporate them. We found that relatively few studies integrated decision making, and even fewer studies aimed to identify solutions that were robust to uncertainty. For management or policy to ensure the delivery of ecosystem services, integrated approaches that incorporate multiple drivers of change and account for multiple sources of uncertainty are needed. This is undoubtedly a challenging task, but ignoring these complexities can result in misleading assessments of the impacts of climate change, suboptimal management outcomes, and the inefficient allocation of resources for climate adaptation.     

Assessment of metabolic diversity within the intestinal microbiota from healthy humans using combined molecular and cultural approaches

The human gut harbours a wide range of bacterial communities that play key roles in supplying nutrients and energy to the host through anaerobic fermentation of dietary components and host secretions. This fermentative process involves different functional groups of microorganisms linked in a trophic chain. Although the diversity of the intestinal microbiota has been studied extensively using molecular techniques, the functional aspects of this biodiversity remain mostly unexplored. The aim of the present work was to enumerate the principal metabolic groups of microorganisms involved in the fermentative process in the gut of healthy humans. These functional groups of microorganisms were quantified by a cultural approach, while the taxonomic composition of the microbiota was assessed by in situ hybridization on the same faecal samples. The functional groups of microorganisms that predominated in the gut were the polysaccharide-degrading populations involved in the breakdown of the most readily available exogenous and endogenous substrates and the predominant butyrate-producing species. Most of the functional groups of microorganisms studied appeared to be present at rather similar levels in all healthy volunteers, suggesting that optimal numbers of these various bacterial groups are crucial for efficient gut fermentation, as well as for host nutrition and health. Significant interindividual differences were, however, confirmed with respect to the numbers of methanogenic archaea, filter paper-degrading and acetogenic bacteria and the products formed by lactate-utilizing bacteria.     

ONTOGENETIC AND SEASONAL VARIATION IN BLOOD PARAMETERS IN SOUTHERN ELEPHANT SEALS

Blood samples were collected from 156 free-ranging southern elephant seals ( Mirounga leonina ) from Peninsula Valdes to study the variation in blood parameters related to ontogeny and the annual cycle. Samples ranged from newborn pups to adults. Interactions between age and sex showed different trends in ontogenetic changes of blood parameters (MANOVA, Wilkis' Lamb-da_12,243= 0.75, P < 0.01). The hematocrit (HCT) and hemoglobin concentration (HB) reached adult levels early in life. Weanlings had 14 % higher HCT than pups, and similar levels to juveniles and adults (HCT range = 46%-62 %). HB of males were below those of females from weaning (18.4 vs . 20.3 g/dl) to adulthood (19.8 vs . 22.3 g/dl). Red blood cell counts (RBC) did not change significantly from pups to juveniles (2.8–3.2 10⁶/μl), but varied for adults at different times of the annual cycle. Breeding females had higher RBC than molting females (3.1 vs. 2.4 10⁶/μl). Changes in blood parameters are related to the development of diving capabilities from pups to juveniles. Changes in adults were associated with different stages of the annual cycle, and these may be the result of the requirements imposed by pregnancy and fasting duration.     

Comparison between the antioxidant status of terrestrial and diving mammals

Many diving mammals are known for their ability to deal with nitrogen supersaturation and to tolerate apnea for extended periods. They are all characterized by high oxygen-carrying capacity in blood together with high oxygen storage in their muscle mass due to large myoglobin concentrations. The above properties theoretically also imply a high tissue antioxidant defenses (AD) to counteract reactive oxygen species (ROS) generation associated with the rapid transition from apnea to reoxygenation. Different enzymatic (superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, and glutathione S-transferase), and non-enzymatic (levels of glutathione) AD as well as cellular damage (thiobarbituric acid-reactive substances contents, as a measure of lipoperoxidation) were measured in blood samples obtained from anesthetized animals, and also in blood obtained from recently dead diving mammals, and compared to some terrestrial mammals (n=5 in both groups). The results confirmed that diving mammals have, in general, higher antioxidant status compared to non-diving mammals. Apparently, to avoid exposure of tissues to changing high oxygen levels, and therefore to avoid an oxidative stress condition related to antioxidant consumption and increased ROS generation, diving mammals possess constitutive high levels of antioxidants in tissues. These data are in agreement with short-term AD adaptations related to torpor and to animals that experience large daily changes in oxygen consumption. These data are similar to the long-term adaptations of animals that undergo hibernation, estivation, freezing-thawing and dehydration-rehydration processes. In summary, animals that routinely face high changes in oxygen availability and/or consumption seem to show a general strategy to prevent oxidative damage by having either appropriate high constitutive AD and/or the ability to undergo arrested states, where depressed metabolic rates minimize the oxidative challenge.     

Tachykinin peptide-induced activation and desensitization of neurokinin 1 receptors

The actions of four tachykinins on inhibition and desensitization of the M-current of bullfrog sympathetic neurons have been characterized. Radioligand binding parameters of the tachykinins were determined at a neurokinin receptor in a heterologous expression system. The correlation between binding, signaling and receptor regulation was investigated. A correlation between receptor binding and signaling was found between the peptides; however, their ability to produce desensitization was not correlated with binding and signaling. These results show that the ability of a tachykinin peptide to induce signal activation is not indicative of its ability to induce receptor regulation.     

PelC is a Pseudomonas aeruginosa outer membrane lipoprotein of the OMA family of proteins involved in exopolysaccharide transport

Pseudomonas aeruginosa is a gram-negative bacterium, opportunistic pathogen, which causes severe acute or chronic infections, as is the case with cystic fibrosis patients. Chronic infections are frequently accompanied by the development of the bacterial population into a specialized community called biofilm. The pelA-G gene cluster of P. aeruginosa has been shown to be involved in pellicle production and biofilm formation. The pel genes have been proposed to contribute to the formation of the exopolysaccharide-containing pellicle. However, the function and the subcellular localization of the seven different Pel proteins are poorly understood. Based on bioinformatics analysis, we have previously considered that PelF is a putative glycosyltransferase (GT4 family), whereas PelG is a Wzx-like polysaccharide transporter from the PST family. In this study we have further characterized the PelC protein. We have shown that PelC is an outer membrane lipoprotein. The N-terminal signal peptide of the PelC lipoprotein is sufficient to target the protein into the membranes. However, by constructing various PelC hybrid proteins we also proposed that efficient and functional outer membrane insertion of PelC requires not only the signal peptide and the lipid modification, but also requires the C-terminal domain of PelC. Because the gene encoding the outer membrane lipoprotein PelC is part of a putative gene cluster involved in exopolysaccharide biogenesis, we suggest that PelC is a new member of the outer membrane auxiliary (OMA) family of lipoprotein whose Wza, involved in Escherichia coli capsular polysaccharide transport, is an archetype.     

Metformin Inhibits Growth of Human Glioblastoma Cells and Enhances Therapeutic Response

High-grade gliomas, glioblastomas (GB), are refractory to conventional treatment combining surgery, chemotherapy, mainly temozolomide, and radiotherapy. This highlights an urgent need to develop novel therapies and increase the efficacy of radio/chemotherapy for these very aggressive and malignant brain tumors. Recently, tumor metabolism became an interesting potential therapeutic target in various cancers. Accordingly, combining drugs targeting cell metabolism with appropriate chemotherapeutic agents or radiotherapy has become attractive. In light of these perspectives, we were particularly interested in the anti-cancer properties of a biguanide molecule used for type 2 diabetes treatment, metformin. In our present work, we demonstrate that metformin decreases mitochondrial-dependent ATP production and oxygen consumption and increases lactate and glycolytic ATP production. We show that metformin induces decreased proliferation, cell cycle arrest, autophagy, apoptosis and cell death in vitro with a concomitant activation of AMPK, Redd1 and inhibition of the mTOR pathway. Cell sensitivity to metformin also depends on the genetic and mutational backgrounds of the different GB cells used in this study, particularly their PTEN status. Interestingly, knockdown of AMPK and Redd1 with siRNA partially, but incompletely, abrogates the induction of apoptosis by metformin suggesting both AMPK/Redd1-dependent and –independent effects. However, the primary determinant of the effect of metformin on cell growth is the genetic and mutational backgrounds of the glioma cells. We further demonstrate that metformin treatment in combination with temozolomide and/or irradiation induces a synergistic anti-tumoral response in glioma cell lines. Xenografts performed in nude mice demonstrate in vivo that metformin delays tumor growth. As current treatments for GB commonly fail to cure, the need for more effective therapeutic options is overwhelming. Based on these results, metformin could represent a potential enhancer of the cytotoxic effects of temozolomide and/or radiotherapy.