Representing crop rotations in life cycle assessment: a review of legume LCA studies

The International Journal of Life Cycle Assessment - There is an imperative to accurately assess the environmental sustainability of crop system interventions in the context of food security and...     

Paradise lost: End‐of‐century warming and acidification under business‐as‐usual emissions have severe consequences for symbiotic corals

Despite recent efforts to curtail greenhouse gas emissions, current global emission trajectories are still following the business‐as‐usual representative concentration pathway (RCP) 8.5 emission pathway. The resulting ocean warming and acidification have transformative impacts on coral reef ecosystems, detrimentally affecting coral physiology and health, and these impacts are predicted to worsen in the near future. In this study, we kept fragments of the symbiotic corals Acropora intermedia (thermally sensitive) and Porites lobata (thermally tolerant) for 7 weeks under an orthogonal design of predicted end‐of‐century RCP8.5 conditions for temperature and pCO₂ (3.5°C and 570 ppm above present‐day, respectively) to unravel how temperature and acidification, individually or interactively, influence metabolic and physiological performance. Our results pinpoint thermal stress as the dominant driver of deteriorating health in both species because of its propensity to destabilize coral–dinoflagellate symbiosis (bleaching). Acidification had no influence on metabolism but had a significant negative effect on skeleton growth, particularly when photosynthesis was absent such as in bleached corals or under dark conditions. Total loss of photosynthesis after bleaching caused an exhaustion of protein and lipid stores and collapse of calcification that ultimately led to A. intermedia mortality. Despite complete loss of symbionts from its tissue, P. lobata maintained small amounts of photosynthesis and experienced a weaker decline in lipid and protein reserves that presumably contributed to higher survival of this species. Our results indicate that ocean warming and acidification under business‐as‐usual CO₂ emission scenarios will likely extirpate thermally sensitive coral species before the end of the century, while slowing the recovery of more thermally tolerant species from increasingly severe mass coral bleaching and mortality. This could ultimately lead to the gradual disappearance of tropical coral reefs globally, and a shift on surviving reefs to only the most resilient coral species.     

French Experience of 2009 A/H1N1v Influenza in Pregnant Women

Background

The first reports on the pandemic influenza 2009 A/H1N1v from the USA, Mexico, and Australia indicated that this disease was associated with a high mortality in pregnant women. The aim of this study was to describe and compare the characteristics of severe critically ill and non-severe pregnant women with 2009 A/H1N1v-related illness in France.

Methodology/Principal Findings

A national registry was created to screen pregnant women with laboratory-confirmed 2009 A/H1N1v influenza. Three hundred and fifteen patients from 46 French hospitals were included: 40 patients were admitted to intensive care units (severe outcomes), 111 were hospitalized in obstetric or medical wards (moderate outcomes), and 164 were outpatients (mild outcomes). The 2009 A/H1N1v influenza illness occurred during all pregnancy trimesters, but most women (54%), notably the severe patients (70%), were in the third trimester. Among the severe patients, twenty (50%) underwent mechanical ventilation, and eleven (28%) were treated with extracorporeal membrane oxygenation. Three women died from A/H1N1v influenza. We found a strong association between the development of a severe outcome and both co-existing illnesses (adjusted odds ratio [OR], 5.1; 95% confidence interval [CI], 2.2–11.8) and a delay in oseltamivir treatment after the onset of symptoms (>3 or 5 days) (adjusted OR, 4.8; 95% CI, 1.9–12.1 and 61.2, 95% CI; 14.4–261.3, respectively). Among the 140 deliveries after 22 weeks of gestation known to date, 19 neonates (14%) were admitted to a neonatal intensive care unit, mainly for preterm delivery, and two neonates died. None of these neonates developed 2009 A/H1N1v infection.

Conclusions

This series confirms the high incidence of complications in pregnant women infected with pandemic A/H1N1v observed in other countries but depicts a lower overall maternal and neonatal mortality and morbidity than indicated in the USA or Australia. Moreover, our data demonstrate the benefit of early oseltamivir treatment in this specific population.     

Long Term Expression of Drosophila melanogaster Nucleoside Kinase in Thymidine Kinase 2-deficient Mice with No Lethal Effects Caused by Nucleotide Pool Imbalances

Mitochondrial DNA depletion caused by thymidine kinase 2 (TK2) deficiency can be compensated by a nucleoside kinase from Drosophila melanogaster (Dm-dNK) in mice. We show that transgene expression of Dm-dNK in Tk2 knock-out (Tk2^−/−) mice extended the life span of Tk2^−/− mice from 3 weeks to at least 20 months. The Dm-dNK^+/−Tk2^−/− mice maintained normal mitochondrial DNA levels throughout the observation time. A significant difference in total body weight due to the reduction of subcutaneous and visceral fat in the Dm-dNK^+/−Tk2^−/− mice was the only visible difference compared with control mice. This indicates an effect on fat metabolism mediated through residual Tk2 deficiency because Dm-dNK expression was low in both liver and fat tissues. Dm-dNK expression led to increased dNTP pools and an increase in the catabolism of purine and pyrimidine nucleotides but these alterations did not apparently affect the mice during the 20 months of observation. In conclusion, Dm-dNK expression in the cell nucleus expanded the total dNTP pools to levels required for efficient mitochondrial DNA synthesis, thereby compensated the Tk2 deficiency, during a normal life span of the mice. The Dm-dNK^+/− mouse serves as a model for nucleoside gene or enzyme substitutions, nucleotide imbalances, and dNTP alterations in different tissues.     

Carriers of Loss-of-Function Mutations in EXT Display Impaired Pancreatic Beta-Cell Reserve Due to Smaller Pancreas Volume

Exotosin (EXT) proteins are involved in the chain elongation step of heparan sulfate (HS) biosynthesis, which is intricately involved in organ development. Loss of function mutations (LOF) in EXT1 and EXT2 result in hereditary exostoses (HME). Interestingly, HS plays a role in pancreas development and beta-cell function, and genetic variations in EXT2 are associated with an increased risk for type 2 diabetes mellitus. We hypothesized that loss of function of EXT1 or EXT2 in subjects with hereditary multiple exostoses (HME) affects pancreatic insulin secretion capacity and development. We performed an oral glucose tolerance test (OGTT) followed by hyperglycemic clamps to investigate first-phase glucose-stimulated insulin secretion (GSIS) in HME patients and age and gender matched non-affected relatives. Pancreas volume was assessed with magnetic resonance imaging (MRI). OGTT did not reveal significant differences in glucose disposal, but there was a markedly lower GSIS in HME subjects during hyperglycemic clamp (iAUC HME: 0.72 [0.46–1.16] vs. controls 1.53 [0.69–3.36] nmol·l⁻¹·min⁻¹, p<0.05). Maximal insulin response following arginine challenge was also significantly attenuated (iAUC HME: 7.14 [4.22–10.5] vs. controls 10.2 [7.91–12.70] nmol·l⁻¹·min⁻¹ p<0.05), indicative of an impaired beta-cell reserve. MRI revealed a significantly smaller pancreatic volume in HME subjects (HME: 72.0±15.8 vs. controls 96.5±26.0 cm³ p = 0.04). In conclusion, loss of function of EXT proteins may affect beta-cell mass and insulin secretion capacity in humans, and render subjects at a higher risk of developing type 2 diabetes when exposed to environmental risk factors.     

3D Microstructural Architecture of Muscle Attachments in Extant and Fossil Vertebrates Revealed by Synchrotron Microtomography

Background

Firm attachments binding muscles to skeleton are crucial mechanical components of the vertebrate body. These attachments (entheses) are complex three-dimensional structures, containing distinctive arrangements of cells and fibre systems embedded in the bone, which can be modified during ontogeny. Until recently it has only been possible to obtain 2D surface and thin section images of entheses, leaving their 3D histology largely unstudied except by extrapolation from 2D data. Entheses are frequently preserved in fossil bones, but sectioning is inappropriate for rare or unique fossil material.

Methodology/Principal Findings

Here we present the first non-destructive 3D investigation, by propagation phase contrast synchrotron microtomography (PPC-SRµCT), of enthesis histology in extant and fossil vertebrates. We are able to identify entheses in the humerus of the salamander Desmognathus from the organization of bone-cell lacunae and extrinsic fibres. Statistical analysis of the lacunae differentiates types of attachments, and the orientation of the fibres, reflect the approximate alignment of the muscle. Similar histological structures, including ontogenetically related pattern changes, are perfectly preserved in two 380 million year old fossil vertebrates, the placoderm Compagopiscis croucheri and the sarcopterygian fish Eusthenopteron foordi.

Conclusions/Significance

We are able to determine the position of entheses in fossil vertebrates, the approximate orientation of the attached muscles, and aspects of their ontogenetic histories, from PPC-SRµCT data. Sub-micron microtomography thus provides a powerful tool for studying the structure, development, evolution and palaeobiology of muscle attachments.     

Modulation of Protease Activated Receptor 1 Influences Human Metapneumovirus Disease Severity in a Mouse Model

Human metapneumovirus (hMPV) infection causes acute respiratory tract infections (RTI) which can result in hospitalization of both children and adults. To date, no antiviral or vaccine is available for this common viral infection. Immunomodulators could represent an interesting strategy for the treatment of severe viral infection. Recently, the role of protease-activated receptors (PAR) in inflammation, coagulation and infection processes has been of growing interest. Herein, the effects of a PAR1 agonist and a PAR1 antagonist on hMPV infection were investigated in BALB/c mice. Intranasal administration of the PAR1 agonist resulted in increased weight loss and mortality of infected mice. Conversely, the PAR1 antagonist was beneficial to hMPV infection by decreasing weight loss and clinical signs and by significantly reducing pulmonary inflammation, pro-inflammatory cytokine levels (including IL-6, KC and MCP-1) and recruitment of immune cells to the lungs. In addition, a significant reduction in pulmonary viral titers was also observed in the lungs of PAR1 antagonist-treated mice. Despite no apparent direct effect on virus replication during in vitro experiments, an important role for PAR1 in the regulation of furin expression in the lungs was shown for the first time. Further experiments indicated that the hMPV fusion protein can be cleaved by furin thus suggesting that PAR1 could have an effect on viral infectivity in addition to its immunomodulatory properties. Thus, inhibition of PAR1 by selected antagonists could represent an interesting strategy for decreasing the severity of paramyxovirus infections.     

When landscape modification is advantageous for protected species. The case of a synanthropic tarantula, Brachypelma vagans

Landscape fragmentation usually has a considerable effect on the genetic and demographic viability of most species because it reduces population size and increases isolation among populations. This situation provokes loss of genetic diversity and increased inbreeding that can lead to population or species extinctions. Some studies also show that landscape fragmentation may have no effect on or even positive consequences for species genetic diversity. The protected tarantula, Brachypelma vagans, exhibits a particular situation in the Mexican Caribbean, which has experienced high lowland and coastal fragmentation because of recent increases in agricultural, urban and touristic development. This modified landscape structure creates favorable conditions for establishment of B. vagans populations in rural settlements. Populations of this tarantula have high densities of individuals, principally females and juveniles, and gene dispersion is assumed by the rare males. Within this context, we studied the influence of natural and anthropogenic fragmentation on the genetic diversity of six B. vagans populations (five continental, one insular), together with their spatial organization. Our approach used seven inter simple sequence repeat markers, which are highly polymorphic markers. The 76 loci selected revealed high genetic variability for continental populations and a low, but not critical situation, for the insular population. We detected a good level of gene exchange among continental populations, and an evident and recent isolation of the island population. This species exhibits a metapopulation structure in the lowlands with numerous local populations where mature females exhibit high birth site fidelity. We conclude that this protected species does not exhibit characteristics to warrant its current conservation status, and we propose complete revision of the ecological and genetic situation for B. vagans in particular, and for all species within the genus Brachypelma in general.