Metabolic processes sustaining the reviviscence of lichen Xanthoria elegans (Link) in high mountain environments.

International audienceTo survive in high mountain environments lichens must adapt themselves to alternating periods of desiccation and hydration. Respiration and photosynthesis of the foliaceous lichen, Xanthoria elegans, in the dehydrated state were below the threshold of CO2-detection by infrared gas analysis. Following hydration, respiration totally recovered within seconds and photosynthesis within minutes. In order to identify metabolic processes that may contribute to the quick and efficient reactivation of lichen physiological processes, we analysed the metabolite profile of lichen thalli step by step during hydration/dehydration cycles, using 31P- and 13C-NMR. It appeared that the recovery of respiration was prepared during dehydration by the accumulation of a reserve of gluconate 6-P (glcn-6-P) and by the preservation of nucleotide pools, whereas glycolytic and photosynthetic intermediates like glucose 6-P and ribulose 1,5-diphosphate were absent. The large pools of polyols present in both X. elegans photo- and mycobiont are likely to contribute to the protection of cell constituents like nucleotides, proteins, and membrane lipids, and to preserve the integrity of intracellular structures during desiccation. Our data indicate that glcn-6-P accumulated due to activation of the oxidative pentose phosphate pathway, in response to a need for reducing power (NADPH) during the dehydration-triggered down-regulation of cell metabolism. On the contrary, glcn-6-P was metabolised immediately after hydration, supplying respiration with substrates during the replenishment of pools of glycolytic and photosynthetic intermediates. Finally, the high net photosynthetic activity of wet X. elegans thalli at low temperature may help this alpine lichen to take advantage of brief hydration opportunities such as ice melting, thus favouring its growth in harsh high mountain climates

Metabolic processes and carbon nutrient exchanges between host and pathogen sustain the disease development during sunflower infection by Sclerotinia sclerotiorum.

International audienceInteractions between the necrotrophic fungus Sclerotinia sclerotiorum and one of its hosts, Helianthus annuus L., were analyzed during fungal colonization of plant tissues. Metabolomic analysis, based on (13)C- and (31)P-NMR spectroscopy, was used to draw up the profiles of soluble metabolites of the two partners before interaction, and to trace the fate of metabolites specific of each partner during colonization. In sunflower cotyledons, the main soluble carbohydrates were glucose, fructose, sucrose and glutamate. In S. sclerotiorum extracts, glucose, trehalose and mannitol were the predominant soluble carbon stores. During infection, a decline in sugars and amino acids was observed in the plant and fungus total content. Sucrose and fructose, initially present almost exclusively in plant, were reduced by 85%. We used a biochemical approach to correlate the disappearance of sucrose with the expression and the activity of fungal invertase. The expression of two hexose transporters, Sshxt1 and Sshxt2, was enhanced during infection. A database search for hexose transporters homologues in the S. sclerotiorum genome revealed a multigenic sugar transport system. Furthermore, the composition of the pool of reserve sugars and polyols during infection was investigated. Whereas mannitol was produced in vitro and accumulated in planta, glycerol was exclusively produced in infected tissues and increased during colonization. The hypothesis that the induction of glycerol synthesis in S. sclerotiorum exerts a positive effect on osmotic protection of fungal cells and favors fungal growth in plant tissues is discussed. Taken together, our data revealed the importance of carbon-nutrient exchanges during the necrotrophic pathogenesis of S. sclerotiorum

An extremely radioresistant green eukaryote for radionuclide bio-decontamination in the nuclear industry

International audienceNuclear activities generate radioactive elements which require processes for their decontamination. Although biological remediation has proved efficient in industrial applications, no biotechnology solution is currently operational for highly radioactive media. Such a solution requires organisms that accumulate radionuclides while withstanding radioactivity. This paper describes the potentialities of an extremophile autotrophic eukaryote, Coccomyxa actinabiotis nov. sp., that we isolated from a nuclear facility and which withstands huge ionizing radiation doses, up to 20,000 Gy. Half the population survives 10,000 Gy, which is comparable to the hyper-radioresistant wellknown prokaryote Deinococcus radiodurans. Cell metabolic profile investigated by nuclear magnetic resonance was hardly affected by radiation doses of up to 10,000 Gy. Cellular functioning completely recovered within a few days. This outstanding microalga also strongly accumulates radionuclides, including 238U, 137Cs, 110mAg, 60Co, 54Mn, 65Zn, and 14C (decontamination above 85% in 24 h, concentration factor, 1,000-450,000 mL g-1 fresh weight). In 1 h, the microalga revealed as effective as the conventional physico-chemical ion-exchangers to purify nuclear effluents. Using this organism, an efficient real-scale radionuclide bio-decontamination process was performed in a nuclear fuel storage pool with an important reduction of waste volume compared to the usual physico-chemical process. The feasibility of new decontamination solutions for the nuclear industry and for environmental clean-up operations is demonstrated

Water footprint in the context of sustainability assessment. Report on the application of life cycle based indicators of water consumption in the context of integrated sustainability impact analysis

Sustainability science explores the interactions between human activities on the Earth’s life support systems. Unless we understand these interactions, we will not be able to design a path towards sustainable development. In this report we focus our attention on water as key resource for human health and ecosystem health and as archetypal resource for which sustainability assessment is needed in order to preserve quality and quantity of the resource for present and future generations. A holistic approach to sustainability assessment of water requires different methodologies able to capture the magnitude of socio-economic drivers related to water consumption: both from production sectors (such as industries and agriculture) and from consumers (domestic use, consumption pattern). The present report aims at presenting different methodologies for depicting sustainability of water use in a life cycle thinking perspective.JRC.H.8 - Sustainability Assessmen

In vivo spectroscopy and NMR metabolite fingerprinting approaches to connect the dynamics of photosynthetic and metabolic phenotypes in resurrection plant Haberlea rhodopensis during desiccation and recovery.

International audienceThe resurrection plant Haberlea rhodopensis was used to study dynamics of drought response of photosynthetic machinery parallel with changes in primary metabolism. A relation between leaf water content and photosynthetic performance was established, enabling us to perform a non-destructive evaluation of the plant water status during stress. Spectroscopic analysis of photosynthesis indicated that, at variance with linear electron flow (LEF) involving photosystem (PS) I and II, cyclic electron flow around PSI remains active till almost full dry state at the expense of the LEF, due to the changed protein organization of photosynthetic apparatus. We suggest that, this activity could have a photoprotective role and prevent a complete drop in adenosine triphosphate (ATP), in the absence of LEF, to fuel specific energy-dependent processes necessary for the survival of the plant, during the late states of desiccation. The NMR fingerprint shows the significant metabolic changes in several pathways. Due to the declining of LEF accompanied by biosynthetic reactions during desiccation, a reduction of the ATP pool during drought was observed, which was fully and quickly recovered after plants rehydration. We found a decline of valine accompanied by lipid degradation during stress, likely to provide alternative carbon sources for sucrose accumulation at late stages of desiccation. This accumulation, as well as the increased levels of glycerophosphodiesters during drought stress could provide osmoprotection to the cells

ANCA-associated vasculitis – Should we change the standard of care?

Collaborative clinical trials over the last 25 years have revolutionised the care of patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. This has led to production of management recommendations and standards of care. This paper reviews the existing standards and the recent evidence that has fed further evolution of standards of care. Pattern recognition remains vital to early diagnosis and therefore initiation treatment. While cyclophosphamide remains the treatment of choice, the advent of rituximab has been shown to be beneficial to patients with relapsing disease. It may be safer in young females and those with a risk of urothelial cancers. Methotrexate and mycophenolate mofetil may not be as good as previously thought for inducing remission. Azathioprine and rituximab are the standards for remission maintenance. There have been recent changes to the nomenclature of vasculitides. It is possible that these will continue to evolve over time to make them more meaningful and inform treatment and prognosis. In the absence of gold-standard biomarkers, we discuss the role of ANCA and histopathology, especially in the Indian setting. Follow-up and monitoring of these patients should include structured evaluation using validated clinical tools, assessing cardiovascular risk, vigilance for infections and other co-morbidities due to exposure to glucocorticoids and immunosuppression

A simple and efficient method for the long-term preservation of plant cell suspension cultures

<p>Abstract</p> <p>Background</p> <p>The repeated weekly subculture of plant cell suspension is labour intensive and increases the risk of variation from parental cells lines. Most of the procedures to preserve cultures are based on controlled freezing/thawing and storage in liquid nitrogen. However, cells viability after unfreezing is uncertain. The long-term storage and regeneration of plant cell cultures remains a priority.</p> <p>Results</p> <p>Sycamore (<it>Acer pseudoplatanus</it>) and Arabidopsis cell were preserved over six months as suspensions cultures in a phosphate-free nutrient medium at 5°C. The cell recovery monitored via gas exchange measurements and metabolic profiling using <it>in vitro </it>and <it>in vivo </it>¹³C- and ³¹P-NMR took a couple of hours, and cell growth restarted without appreciable delay. No measurable cell death was observed.</p> <p>Conclusion</p> <p>We provide a simple method to preserve physiologically homogenous plant cell cultures without subculture over several months. The protocol based on the blockage of cell growth and low culture temperature is robust for heterotrophic and semi-autotrophic cells and should be adjustable to cell lines other than those utilised in this study. It requires no specialized equipment and is suitable for routine laboratory use.</p

Two cases of lymphoepithelial cyst of the pancreas

A 35-year-old man was found to have a cystic mass in the pancreatic body on a routine health examination ; high serum CA19-9 was also detected. The enucleated cyst was diagnosed as a lymphoepithelial cyst (LEC). A 74-year-old man found to have a cystic mass in the pancreatic head by computer tomography as well as high serum CA19-9 was suspected of a cystic neoplasm of the pancreas (IPMN), and pylorus-preserving pancreaticoduodenectomy (PPPD) was performed. Pathologically, the cyst was found to be LEC. It is often difficult to diagnose pancreatic cyst as LEC preoperatively. Care should be taken not to do over-surgery for benign disease LEC

Cash Flow Optimization on Synthetic CDOs

Collateralized Debt Obligations are not as widely used nowadays as they were before 2007 Subprime crisis. Nonetheless there remains an enthralling challenge to optimize cash flows associated with synthetic CDOs. A Gaussian-based model is used here in which default correlation and unconditional probabilities of default are highlighted. Then numerous simulations are performed based on this model for different scenarios in order to evaluate the associated cash flows given a specific number of defaults at different periods of time. Cash flows are not solely calculated on a single bought or sold tranche but rather on a combination of bought and sold tranches. With some assumptions, the simplex algorithm gives a way to find the maximum cash flow according to correlation of defaults and maturities. The used Gaussian model is not realistic in crisis situations. Besides present system does not handle buying or selling a portion of a tranche but only the whole tranche. However the work provides the investor with relevant elements on how to know what and when to buy and sell