Chlorophyll Synthesis in Dark-Grown Pine Primary Needles

The pigment content of dark-grown primary needles of Pinus jeffreyi L. and Pinus sylvestris L. was determined by high-performance liquid chromatography. The state of protochlorophyllide a and of chlorophylls during dark growth were analyzed by in situ 77 K fluorescence spectroscopy. Both measurements unambiguously demonstrated that pine primary needles are able to synthesize chlorophyll in the dark. Norflurazon strongly inhibited both carotenoid and chlorophyll synthesis. Needles of plants treated with this inhibitor had low chlorophyll content, contained only traces of xanthophylls, and accumulated carotenoid precursors. The first form of chlorophyll detected in young pine needles grown in darkness had an emission maximum at 678 nm. Chlorophyll-protein complexes with in situ spectroscopic properties similar to those of fully green needles (685, 695, and 735 nm) later accumulated in untreated plants, whereas in norflurazon-treated plants the photosystem I emission at 735 nm was completely lacking. To better characterize the light-dependent chlorophyll biosynthetic pathway in pine needles, the 77 K fluorescence properties of in situ protochlorophyllide a spectral forms were studied. Photoactive and nonphotoactive protochlorophyllide a forms with emission properties similar to those reported for dark-grown angiosperms were found, but excitation spectra were substantially red shifted. Because of their lower chlorophyll content, norflurazon-treated plants were used to study the protochlorophyllide a photoreduction process triggered by one light flash. The first stable chlorophyllide photoproduct was a chlorophyllide a form emitting at 688 nm as in angiosperms. Further chlorophyllide a shifts usually observed in angiosperms were not detected. The rapid regeneration of photoactive protochlorophyllide a from nonphotoactive protochlorophyllide after one flash was demonstrated.     

Agarose as a suitable substrate for use in the study of Al dynamics in the rhizosphere

Because of experimental difficulties, few authors have studied the dynamics of aluminium in the rhizosphere. The aim of this paper is to present a suitable method for studying rhizosphere Al dynamics. It is based on the use of agarose as a substrate for plant growth. Agar and agarose gels are often used in rhizosphere studies, but most are poorly characterized and occasionally give rise to experimental artefacts, especially with low mobility elements like Al. The results reported here show that agarose is a relatively pure substrate, nearly devoid of phosphorus and other Al-complexing substances. Aqueous extracts of agarose also exhibit Al phytotoxicity equivalent to that of a nutrient solution. Since this substrate has the properties of a variable charge exchange complex, it can be considered as a physico-chemical model for organic matter. Finally, its Al adsorption capacity is high enough for the Al reserve in the substrate not to exert a limiting effect on plants and low enough to allow accurate measurement of Al depletion in the rhizophere.     

Evidence for the nitrate-dependent spatial regulation of the nitrate reductase gene in chicory roots

Young chicory plants (Cichorium intybus L. var. Witloof) show a tenfold higher nitrate reductase NR activity in roots compared to leaves. Northern analysis revealed, besides the nitrate inducibility of the nitrate reductase gene (nia), a higher level of expression in the roots. By modifying the external nitrate concentration the NR activity in the leaves remained negligible whereas a maximal activity was observed in the roots when grown in the presence of 5 mM nitrate. Surprisingly, variation of the external nitrate concentration induced changes in the spatial regulation of nia within the root. In-situ hybridization mainly localized nia mRNA in the cortical cells of roots grown at low nitrate concentrations (0.2 mM). At high nitrate concentrations (5 mM), nia mRNA was more abundant in the vascular tissues. The root apex revealed a strong signal under both conditions. The isolation and characterization of the NR structural gene from chicory is also presented. Southern blot analysis revealed the presence of a single nia gene per haploid genome of chicory.     

NtTPN1: a RPP8‐like R gene required for Potato virus Y‐induced veinal necrosis in tobacco

Potato virus Y (PVY) is one of the most damaging viruses of tobacco. In particular, aggressive necrotic strains (PVY^N) lead to considerable losses in yield. The main source of resistance against PVY is linked to the va locus. However, va‐overcoming PVY isolates inducing necrotic symptoms were observed in several countries. In this context, it is important to find va‐independent protection strategies. In a previous study, the phenotyping of 162 tobacco varieties revealed 10 accessions that do not carry the va allele and do not exhibit typical PVY^N‐induced veinal necrosis. Despite the absence of necrotic symptoms, normal viral accumulation in these plants suggests a va‐independent mechanism of tolerance to PVY^N‐induced systemic veinal necrosis. Fine mapping of the genetic determinant(s) was performed in a segregating F2 population. The tolerance trait is inherited as a single recessive gene, and allelism tests demonstrated that eight of the 10 tolerant varieties carry the same determinant. Anchoring the linkage map to the tobacco genome physical map allowed the identification of a RPP8‐like R gene, called NtTPN1 (for t abacum P VY‐induced 相似文献   

From value-added tax to a damage and value-added tax partially based on life cycle assessment: principles and feasibility

Purpose

The purpose of this article is to examine the arguments in favor of a shift from value-added tax (VAT) or sales tax to a damage and value-added tax (DaVAT) partially based on the life cycle assessment (LCA) of goods and services. With this shift, goods and services that seriously harm the environment and human health will be priced up, those that impact them less will be priced down. The paper recalls the proposal made by De Camillis and Goralczyk (Int J Life Cycle Assess 18:263–272, 2013) to differentiate the VAT rate associated with products according to their environmental impacts over their life cycle. The paper suggests a new way to convert VAT into DaVAT, examines the operating principles of such a system, and considers its practical feasibility. The new policy tool based on LCA presented is intended to be applied to every country wishing to reform its consumption tax system in order to strive for a more sustainable future. Some aspects specific to countries having the same currency, notably the Euro zone, are also discussed.

Methods

The proposal of De Camillis and Goralczyk is discussed from the perspective of both environmental performance and compliance with LCA standards. To overcome the identified difficulties, a new way of adapting VAT (or consumption taxes in general) according to LCA is suggested. The proposal relies on three essential points: (i) apply VAT (or consumption taxes in general) to all goods and services and reduce its multiple rates to one single low rate (e.g., 3%) called uniform VAT (UVAT); (ii) add to UVAT a per-unit tax called global damage tax (GDT) calculated on the basis of environmental impacts assessed by means of specific or generic LCAs. In the case of potentially high-polluting products or industries, a specific LCA will be automatically imposed. The obligation to assess high-polluting activities already exists in many countries with, e.g., environmental impact studies, but the impacts are not necessarily evaluated by LCA; (iii) in order to reflect environmental, social, or ethical concerns specific to a country, another damage tax termed specific damage tax (SDT) is proposed that extends beyond LCA. DaVAT is the sum of UVAT, GDT, and SDT. DaVAT is conceived not as an additional burden but rather as a shift of taxation, as the rate of the old consumption taxes can decrease proportionally to the increase of GDT. DaVAT is also designed in such a way that the erosion of tax revenues, when pollutant would decline, is offset by the extension of the tax to all goods and services and by the possibility to gradually re-increase the UVAT rate when the number of highly polluting products decreases.

Results and discussion

The proposal is examined first from a theoretical point of view by considering which principles should be used to comply with LCA standards and general requirements of (environmental) tax policies. Four general principles emerge: consistency in the choice of the functional unit and in the characterization, normalization and weighting methods, transparency of information about the environmental score of the product, evolution capacity of the levers of the tax and of the assessment methods, respect for national sovereignty concerning the setting of the tax price. The proposal is also examined from a practical point of view by asking how the DaVAT system would work in practice. The answer takes into account associated costs, risks of fraud, price changes, and acceptability of the proposal. The issue about price changes is addressed on the basis of a simulation drawn from six published LCA studies on different products.

Conclusions

The proposal to replace most of the VAT or sales tax with a unitary global damage tax based on LCA of goods and services seems to meet expectations not only in terms of theoretical consistency and practical feasibility but also from the perspective of income tax consolidation, environmental efficiency, and sustainable growth. The study concludes by pointing out the limits of an LCA-based tax and by suggesting a framework for a closer examination of the DaVAT system in order to verify that it would provide the intended incentives and to explore the modalities of its implementation.

     

Evidence for the possible occurrence of Grave’s disease in a blue-eyed black lemur (<Emphasis Type="Italic">Eulemur flavifrons</Emphasis>)

The blue-eyed black lemur (Eulemur flavifrons) is classified by the International Union for Conservation of Nature (IUCN) as critically endangered. A 23-year-old male housed at Mulhouse Zoo presented with lethargy, polyphagia, alopecia, and chronic weight loss. Clinical examination suggested an endocrine pathology such as hyperthyroidism. Secondary examinations included cervical ultrasound, thyroid biopsy, and scintigraphy. The latter revealed elevated thyroid activity. Blood analysis was performed to measure the level of anti-receptor thyroid-stimulating hormone antibodies, which allowed us to test the autoimmune hypothesis. The high level of antibodies together with levels of thyroid-stimulating hormone and the scintigraphy images led to the diagnosis of Grave’s disease. Carbimazole treatment followed by thyroidectomy resulted in a quick weight gain and general improvement in health status. The following breeding season, the treated individual sired an offspring. To the authors’ knowledge, this is the first report of likely Grave’s disease in a non-human primate.     

A Catalytically Disabled Double Mutant of Src Tyrosine Kinase Can Be Stabilized into an Active-Like Conformation

Tyrosine kinases are enzymes playing a critical role in cellular signaling. Molecular dynamics umbrella sampling potential of mean force computations are used to quantify the impact of activating and inactivating mutations of c-Src kinase. The potential of mean force computations predict that a specific double mutant can stabilize c-Src kinase into an active-like conformation while disabling the binding of ATP in the catalytic active site. The active-like conformational equilibrium of this catalytically dead kinase is affected by a hydrophobic unit that connects to the hydrophobic spine network via the C-helix. The αC-helix plays a crucial role in integrating the hydrophobic residues, making it a hub for allosteric regulation of kinase activity and the active conformation. The computational free-energy landscapes reported here illustrate novel design principles focusing on the important role of the hydrophobic spines. The relative stability of the spines could be exploited in future efforts to artificially engineer active-like but catalytically dead forms of protein kinases.     

Characterizing alternative feeds for rainbow trout (<Emphasis Type="Italic">O. mykiss</Emphasis>) by <Superscript>1</Superscript>H NMR metabolomics

Introduction

Fish feed formulations are constantly evolving to improve the quality of diets for farmed fish and to ensure the sustainability of the aquaculture sector. Nowadays, insect, microalgae and yeast are feedstuff candidates for new feeds. However, the characterization of aquafeed is still based on proximate and targeted analyses which may not be sufficient to assess feed quality.

Objectives

Our aim was to highlight the soluble compounds that specifically differ between selected plant-based feeds complemented with alternative feedstuffs and discuss their origin and potential for fish nutrition.

Methods

A growth trial was carried out to evaluate growth performances and feed conversion ratios of fish fed plant-based, commercial, insect, spirulina and yeast feeds. ¹H NMR metabolomics profiling of each feed was performed using a CPMG sequence on polar extracts. Spectra were processed, and data were analyzed using multivariate and univariate analyses to compare alternative feeds to a plant-based feed.

Results

Fish fed insect or yeast feed showed the best growth performances associated with the lowest feed conversion ratios compared to plant-based feed. Soluble compound ¹H NMR profiles of insect and spirulina alternative feeds differed significantly from the plant-based one that clustered with yeast feed. In insect and spirulina feeds, specific differences compared to plant-based feed concerned glycerol and 3-hydroxybutyrate, respectively.

Conclusion

This strategy based on compositional differences between plant-based and alternative feeds can be useful for detecting compounds unsuspected until now that could impact fish metabolism.