A diminution in ascorbate oxidase activity affects carbon allocation and improves yield in tomato under water deficit

The regulation of carbon allocation between photosynthetic source leaves and sink tissues in response to stress is an important factor controlling plant yield. Ascorbate oxidase is an apoplastic enzyme, which controls the redox state of the apoplastic ascorbate pool. RNA interference was used to decrease ascorbate oxidase activity in tomato (Solanum lycopersicum L.). Fruit yield was increased in these lines under three conditions where assimilate became limiting for wild‐type plants: when fruit trusses were left unpruned, when leaves were removed or when water supply was limited. Several alterations in the transgenic lines could contribute to the improved yield and favour transport of assimilate from leaves to fruits in the ascorbate oxidase lines. Ascorbate oxidase plants showed increases in stomatal conductance and leaf and fruit sugar content, as well as an altered apoplastic hexose : sucrose ratio. Modifications in gene expression, enzyme activity and the fruit metabolome were coherent with the notion of the ascorbate oxidase RNAi lines showing altered sink strength. Ascorbate oxidase may therefore be a target for strategies aimed at improving water productivity in crop species.     

The Leeds Evaluation of Efficacy of Detoxification Study (LEEDS) Prisons Project Study: protocol for a randomised controlled trial comparing methadone and buprenorphine for opiate detoxification

Many research-funding agencies now require open access to the results of research they have funded, and some also require that researchers make available the raw data generated from that research. Similarly, the journal Trials aims to address inadequate reporting in randomised controlled trials, and in order to fulfil this objective, the journal is working with the scientific and publishing communities to try to establish best practice for publishing raw data from clinical trials in peer-reviewed biomedical journals. Common issues encountered when considering raw data for publication include patient privacy – unless explicit consent for publication is obtained – and ownership, but agreed-upon policies for tackling these concerns do not appear to be addressed in the guidance or mandates currently established. Potential next steps for journal editors and publishers, ethics committees, research-funding agencies, and researchers are proposed, and alternatives to journal publication, such as restricted access repositories, are outlined.     

A new species of Dyrosaurus (Crocodylomorpha, Dyrosauridae) from the early Eocene of Morocco: phylogenetic implications

A new dyrosaurid is described from the Ypresian of the phosphatic deposits of the Oulad Abdoun Basin of Morocco. It is based on numerous cranial and postcranial remains, allowing an almost complete reconstruction. This new Dyrosaurus species, Dyrosaurus maghribensis sp. nov. , is currently only known from Morocco. It differs from D. phosphaticus , present in contemporaneous levels of Algeria and Tunisia, by several autapomorpies, including a smooth dorsal margin of the parietal and widely opened choanae. A phylogenetic analysis, using 47 taxa and 234 morphological characters, shows the dyrosaurids as the sister taxon of pholidosaurids, which include Elosuchus , Sarcosuchus , Terminonaris and Pholidosaurus , and the thalattosuchians. Goniopholididae is a non-monophyletic group; however, if dyrosaurids are not included in the analysis, the result differs and the goniopholidids form a distinct clade. If Thalattosuchia is excluded, both Goniopholididae and Pholidosauridae become paraphyletic assemblages. Thus, phylogenetic problems remain with respect to longirostrine clade, and more attention should be paid to resolving their evolutionary relationships amongst the crocodyliforms.  © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 148 , 603–656.     

Factors Mediating the Vitamin B12 Requirement of Euglena

SYNOPSIS. Deprived of vitamin B₁₂, Euglena gracilis strain Z ceases to divide which we believe to be a function of the light regime: division inhibition occurs more quickly in continuous light than in alternating (6L : 6D) light and not at all in total darkness. This phenomenon is dependent on the carbon source; cells grown in glutamate-malate medium do not divide regardless of the culture conditions while dl -lactate as carbon source permits growth in darkness in the absence of B₁₂. Conditions which lead to an increased O₂ or decreased CO₂ tension in the medium, such as agitation in darkness or incubation in red or white light, result in inhibition of division. This inhibition can be reversed by re-transferring the cells to still culture in the dark or, in the case of light-induced blockage, by the addition of DCMU.     

Deconvolution of pigment and physiologically related photochemical reflectance index variability at the canopy scale over an entire growing season

The sensitivity of the photochemical reflectance index (PRI) to leaf pigmentation and its impacts on its potential as a proxy for light‐use efficiency (LUE) have recently been shown to be problematic at the leaf scale. Most leaf‐to‐leaf and seasonal variability can be explained by such a confounding effect. This study relies on the analysis of PRI light curves that were generated at the canopy scale under natural conditions to derive a precise deconvolution of pigment‐related and physiologically related variability in the PRI. These sources of variability were explained by measured or estimated physiologically relevant variables, such as soil water content, that can be used as indicators of water availability and canopy chlorophyll content. The PRI mainly reflected the variability in the pigment content of the canopy. However, the corrected PRI, which was obtained by subtracting the pigment‐related seasonal variability from the PRI measurement, was highly correlated with the upscaled LUE measurements. Moreover, the sensitivity of the PRI to the leaf pigment content may mask the PRI versus LUE relationship or result in an artificial relationship that reflects the relationship of chlorophyll versus LUE, depending on the species phenology.     

Antimicrobial activity of different proteins and their fragments from Bacillus thuringiensis parasporal crystals against clostridia and archaea

Proteins of parasporal crystals (Cry proteins) from entomopathogenic bacterium Bacillus thuringiensis (subspecies kurstaki, galleriae, tenebrionis) as well as some fragments of these proteins, obtained by limited proteolysis, are capable of antimicrobial action against anaerobic bacteria and archaea-Clostridium butyricum, Clostridium acetobutylicum and Methanosarcina barkeri. The MICs are 45-150 microg/mL. Electron microscopy showed that lysis of M. barkeri cells in the presence of 49kDa fragment of Cry3Aa toxin is generally similar to the bacterial cell lysis, which has been previously detected in the presence of Cry11A, Cry1Ab and other Cry proteins. The Cry1D-like toxin from crystals of B. thuringiensis subsp. galleriae has been put forward as an example of the supposition that cell wall and some of its components like teichoic acid and N-acetylgalactosamine have possible influence on Cry toxins, enhancing their antimicrobial activity. The possible ecological role of the antimicrobial activity of Cry proteins is also discussed.     

Role of Aromatic Amino-acid Residues in the Binding of Enzymes and Proteins to Nucleic Acids

MANY studies have been made of the specificity of interaction between nucleic acids and polypeptides, proteins and enzymes^1,2. Electrostatic forces between basic amino-acids and phosphate groups contribute to the stability of the complexes, but selective recognition requires more specific interactions which are not yet understood. The recognition of a specific region of a nucleic acid could be explained if this region has some particular conformation or if there are specific interactions between a few amino-acid residues and the bases of this region. We wish to report results which show that the aromatic amino-acids tryptophan and tyrosine can interact with nucleic acid bases in double stranded nucleic acids. They suggest that aromatic amino-acid residues of enzymes and proteins could participate in the binding to nucleic acids by intercalating between the bases and thus constraining the nucleic acid molecule to adopt a definite position with respect to the protein molecule.     

Genetic structure of the endangered perennial plant Eryngium alpinum (Apiaceae) in an alpine valley

We investigated the genetic structure of Eryngium alpinum (Apiaceae) in an Alpine valley where the plant occurs in patches of various sizes. In a conservation perspective, our goal was to determine whether the valley consists of one or several genetic units. Habitat fragmentation and previous observations of restricted pollen/seed dispersal suggested pronounced genetic structure, but gene dispersal often follows a leptokurtic distribution, which may lead to weak genetic structure. We used nine microsatellite loci and two nested sampling designs (50 × 50 m grid throughout the valley and 2 × 2 m grid in two 50 × 10 m quadrats). Within the overall valley, F -statistics and Bayesian approaches indicated high genetic homogeneity. This result might be explained by: (1) underestimation of long-distance pollen/seed dispersal by in situ experiments and (2) too recent fragmentation events to build up genetic structure. Spatial autocorrelation revealed isolation by distance on the overall valley but this pattern was much more pronounced in the 50 × 10 m quadrats sampled with a 2-m mesh. This was probably associated with limited primary seed dispersal, leading to the spatial clustering of half-sibs around maternal plants. We emphasize the interest of nested sampling designs and of combining several statistical tools.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 667–677.