Flavonoid variability within and between natural populations of Pinus uncinata

A total of 120 individual trees representative of Pinus uncinata were analysed for their foliar flavonoid content. The ratio of two extracted anthocyanidins, prodelphinidin and procyanidin, is a constant. Among the flavonols quercetin, kaempfrerol and isorhamnetin, the percentage of quercetin discriminates the five studied populations. Its distribution conforms to the Hardy-Weinberg law, but the ratio of the two implicit alleles proves the originality of each population, and leads to the recognition of distinct chemotypes.     

Equine CTNNB1 and PECAM1 nucleotide structure and expression analyses in an experimental model of normal and pathological wound repair

Background  

Wound healing in horses is fraught with complications. Specifically, wounds on horse limbs often develop exuberant granulation tissue which behaves clinically like a benign tumor and resembles the human keloid in that the evolving scar is trapped in the proliferative phase of repair, leading to fibrosis. Clues gained from the study of over-scarring in horses should eventually lead to new insights into how to prevent unwanted scar formation in humans. cDNA fragments corresponding to CTNNB1 (coding for β-catenin) and PECAM1, genes potentially contributing to the proliferative phase of repair, were previously identified in a mRNA expression study as being up-regulated in 7 day wound biopsies from horses. The aim of the present study was to clone full-length equine CTNNB1 and PECAM1 cDNAs and to study the spatio-temporal expression of mRNAs and corresponding proteins during repair of body and limb wounds in a horse model.     

Evolution de la radioactivité des cellules neurosécrétrices de la pars intercerebralis chez Locusta migratoria migratorioides (Insecte Orthoptère) après injection de cystéine S35

Résumé Après injection de cystéine S³⁵, les cellules A, B, C et les neurones banaux de la pars intercerebralis chez Locusta (femelles immatures et mûres) sont radioactifs. Le taux d' incorporation de la cystéine S³⁵ dans les cellules B est identique chez toutes les femelles et il est légèrement supérieur à celui des neurones banaux. Ces résultats confirment l'inactivité sécrétoire protéique des cellules B. Les cellules C incorporent 3 à 5 fois plus de cystéine S³⁵ que les neurones banaux. Elles synthétisent donc une ou plusieurs protéines contenant de la cystéine ce qui réaffirme leur activité neurosécrétrice chez Locusta. Les cellules A possèdent le taux d'incorporation de cystéine S³⁵ le plus élevé: 5 à 8 fois celui des neurones banaux.Chez toutes les femelles, les cellules A synthétisent plus de neurosécrétion et en éliminent proportionellement plus que les cellules C. La neurosécrétion A est élaborée sous sa forme figurée plus rapidement (30 min) que la neurosécrétion C (60 min). Le renouvellement de la neurosécrétion A est donc quantitativement plus important et plus rapide que celui de la neurosécrétion C. Chez les femelles immatures, les cellules A et C synthétisent plus de matériel et en éliminent proportionnellement plus que chez les femelles mûres. Le temps nécessaire à l'élaboration et à la vidange des grains de neurosécrétion A est identique chez toutes les femelles. Il en est de même pour le matériel C. Le renouvellement des neurosécrétions A et C est donc plus important chez les femelles immatures que chez les femelles mûres mais il n'est pas plus rapide. L'accumulation du matériel fuchsinophile dans les cellules A et C lors de la maturation ovarienne correspond à une réduction de leur fonction neurosécrétrice: elle résulte d'une diminution de l'activité d'élimination des cellules neurosécrétrices A et C supérieure à l'affaiblissement de leur activité de synthèse.

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Evolution of the radioactivity of the neurosecretory cells of pars intercerebralis in Locusta migratoria migratorioides (insect orthoptera) after injection of ³⁵S-cysteineAn autoradiographic study by optical and electronic microscopy

Summary After injection of ³⁵S-cysteine, the A, B, C cells and the ordinary neurones of pars intercerebralis in Locusta — immature and mature females — are radioactive. The rate of incorporation of ³⁵S-cysteine into the B cells is the same for all the females, and it is slightly higher than the rate of incorporation of ³⁵S-cysteine into the ordinary neurones. These results demonstrate the proteinic secretory inactivity of the B cells. The C cells incorporate 3 to 5 times more ³⁵S-cysteine than ordinary neurones. Thus, the C cells synthesize one protein or several proteins with cysteine; this observation confirms their neurosecretory activity in Locusta. The A cells have the highest rate of incorporation of ³⁵S-cysteine: 5 to 8 times the one of ordinary neurones.In all the females, the A cells produce and release proportionally more neurosecretion than the C cells. The production of granules is faster in A cells (30 min) than in C cells (60 min). The turnover of the A neurosecretion is consequently higher and quicker than the C neurosecretion. In immature females, the A and C cells synthesize and release proportionally more material than in mature females. The time necessary for production and release of the A neurosecretion is the same for all the females. It is so for the C material. The turnover of the A and C neurosecretions is thus more important in immature females than in mature females but it is not more rapid. The accumulation of stainable neurosecretory material in A and C cells at the time of ovarian maturation is associated with a reduction of their neurosecretory activity: it is due to a decrease of the rate of release of the A and C cells being more important than their rate of production.

     

Osmotic stress alters the balance between organic and inorganic solutes in flax (Linum usitatissimum)

Flax (Linum usitatissimum) is grown for its oil and its fiber. This crop, cultivated in temperate regions, has seen a renewed interest due to the presence of abundant molecules of interest for many applications. Little information is available about the behavior of flax during osmotic stress; yet this is considered a major stress that causes significant yield losses in most crops. To control the presence of this stress better, flax behavior was investigated following the application of osmotic stress and the response was examined by applying increasing concentrations of PEG 8000. This resulted in the reorganization of 32 metabolites and 6 mineral ions in the leaves. The analysis of these two types of solute highlighted the contrasting behavior between a higher metabolite content (particularly fructose, glucose and proline) and a decrease in mineral ions (especially nitrate and potassium) following PEG treatment. However, this reorganization did not lead to a greater accumulation of solutes, with the total amount remaining unchanged in leaves during osmotic stress.     

Elucidation of direct competition and allosteric modulation of small‐molecular‐weight protein ligands using surface plasmon resonance methods

The present work introduces a surface plasmon resonance‐based method for the discrimination of direct competition and allosteric effects that occur in ternary systems comprising a receptor protein and two small‐molecular‐weight ligands that bind to it. Fatty acid binding protein 4, fructose‐1,6‐bisphosphatase and human serum albumin were used as model receptor molecules to demonstrate the performance of the method. For each of the receptor molecules, pairs of ligand molecules were selected for which either direct competition or an allosteric effect had already been determined by other methods. The method of discrimination introduced here is based on the surface plasmon resonance responses observed at equilibrium when an immobilized receptor protein is brought into contact with binary mixtures of interacting ligands. These experimentally determined responses are compared with the responses calculated using a theoretical model that considers both direct competition and allosteric ligand interaction modes. This study demonstrates that the allosteric ternary complex model, which enables calculation of the fractional occupancy of the protein by each ligand in such ternary systems, is well suited for the theoretical calculation of these types of responses. For all of the ternary systems considered in this work, the experimental and calculated responses in the chosen concentration ratio range were identical within a five‐σ confidence interval when the calculations considered the correct interaction mode of the ligands (direct competition or different types of allosteric regulation), and in case of allosteric modulation, also the correct strength of this effect. This study also demonstrates that the allosteric ternary complex model‐based calculations are well suited to predict the ideal concentration ratio range or even single concentration ratios that can serve as hot spots for discrimination, and such hot spots can drastically reduce the numbers of measurements needed for discrimination between direct competition and distinct modulation modes (neutral, positive or negative allostery). Copyright © 2015 John Wiley & Sons, Ltd.     

Increased susceptibility to oxidative stress as a proximate cost of reproduction

In iteroparous species high investment in current reproduction is usually paid in terms of reduced future reproduction and increased mortality. However, the proximal mechanisms of these costs remain poorly understood. Free radicals arising as by‐products of normal metabolic activities have deleterious effects on cellular proteins, lipids and DNA, and this phenomenon is known as oxidative stress. Since reproduction is an energetically demanding activity, which increases both basal and field metabolic rates, one could expect that breeding effort generates an oxidative stress whose strength depends on the availability and efficiency of antioxidant defences. In agreement with this prediction, we show here for the first time that reproduction decreases antioxidant defences, illustrating that oxidative stress represents a cost of reproduction. We suggest that increased susceptibility to oxidative stress might be a general proximal connection between reproduction and survival underlying other mechanistic links previously acknowledged.