Ecological and evolutionary drivers of phenotypic and genetic variation in the European crabapple [Malus sylvestris (L.) Mill.], a wild relative of the cultivated apple.

BACKGROUND AND AIMS: Studying the relationship between phenotypic and genetic variation in populations distributed across environmental gradients can help us to understand the ecological and evolutionary processes involved in population divergence. We investigated the patterns of genetic and phenotypic diversity in the European crabapple, Malus sylvestris, a wild relative of the cultivated apple (Malus domestica) that occurs naturally across Europe in areas subjected to different climatic conditions, to test for divergence among populations. METHODS: Growth rates and traits related to carbon uptake in seedlings collected across Europe were measured in controlled conditions and associated with the genetic status of the seedlings, which was assessed using 13 microsatellite loci and the Bayesian clustering method. Isolation-by-distance, isolation-by-climate and isolation-by-adaptation patterns, which can explain genetic and phenotypic differentiation among M. sylvestris populations, were also tested. KEY RESULTS: A total of 11.6 % of seedlings were introgressed by M. domestica, indicating that crop-wild gene flow is ongoing in Europe. The remaining seedlings (88.4 %) belonged to seven M. sylvestris populations. Significant phenotypic trait variation among M. sylvestris populations was observed. We did not observe significant isolation by adaptation; however, the significant association between genetic variation and the climate during the Last Glacial Maximum suggests that there has been local adaptation of M. sylvestris to past climates. CONCLUSIONS: This study provides insight into the phenotypic and genetic differentiation among populations of a wild relative of the cultivated apple. This might help us to make better use of its diversity and provide options for mitigating the impact of climate change on the cultivated apple through breeding.

Pressure-induced transformations in LiCl-H2O at 77 K.

A systematic study of the properties of high-density amorphous ice (HDA) in the presence of increasing amounts of salt is missing, especially because it is challenging to avoid ice crystallization upon cooling the pressurized liquid. In order to be able to study HDA also in the presence of small amounts of salt, we have investigated the transformation behaviour of quenched aqueous LiCl solutions (mole fraction x < 0.25) upon pressurization in a piston-cylinder setup at 77 K. The sample properties were characterized by in situ dilatometry under high pressure conditions and after recovery by ex situ powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC) at ambient pressure. Two regimes can be identified, with a rather sharp switch at about x = 0.12. At x < 0.12 the samples show the phenomenology also known for pure water samples. They are composed mainly of hexagonal ice (Ih) and experience pressure-induced amorphization to HDA at P > 1 GPa. The observed densification is consistent with the idea that a freeze concentrated LiCl solution of x = 0.14 (R = 6) segregates, which transforms to the glassy state upon cooling, and that the densification is only due to the Ih → HDA transition. Also the XRD patterns and DSC scans are almost unaffected by the presence of the segregated glassy LiCl solution. Upon heating at ambient pressure HDA experiences the polyamorphic transition to low-density amorphous ice (LDA) at ∼120 K, even at x ∼ 0.10. Based on the latent heat evolved in the transition we suggest that almost all water in the sample transforms to an LDA-like state, even the water in the vicinity of the ions. The glassy LiCl solution acts as a spectator that does not shift the transformation temperature significantly and experiences a glass-to-liquid transition at ∼140 K prior to the crystallization to cubic ice. By contrast, at x > 0.12 the phenomenology completely changes and is now dominated by the salt. Hexagonal ice no longer forms upon quenching the LiCl solution, but instead LDA forms. A broad pressure-induced transformation at >0.6 GPa can be attributed to the densification of LDA, the glassy LiCl solution and/or glassy hydrates.

Structure of supercooled water in clusters and bulk and its relation to the two-state picture of water: results from the TIP4P-ice model.

The structure of water clusters (H(2)O)(n) (n = 40-200) and bulk water were examined by molecular dynamics simulations using the TIP4P-ice water model. The analysis of the low-temperature structures in terms of the local structure index (LSI) showed a bimodal distribution. This finding supports the two-state picture derived from the analysis of the inherent dynamics of bulk SPC/E water. The water molecules at the outer interface of the coldest clusters are more structured than those in the inner core. The geometrical constraint of the interface forces the surface molecules to lose one neighbor and adopt a local angular distribution of hydrogen bonds resembling that found in the basal plane of ice Ih.

Effect of salts on the properties of aqueous sugar systems, in relation to biomaterial stabilization. 1. Water sorption behavior and ice crystallization/melting.

Trehalose and sucrose, two sugars that are involved in the protection of living organisms under extreme conditions, and their mixtures with salts were employed to prepare supercooled or freeze-dried glassy systems. The objective of the present work was to explore the effects of different salts on water sorption, glass transition temperature (T(g)), and formation and melting of ice in aqueous sugar systems. In the sugar-salt mixtures, water adsorption was higher than expected on the basis of the water uptake by each pure component. In systems with a reduced mass fraction of water (w less-than-or-equal 0.4), salts delayed water crystallization, probably due to ion-water interactions. In systems where > 0.6, water crystallization could be explained by the known colligative properties of the solutes. The glass transition temperature of the maximally concentrated matrix (T(g)') was decreased by the presence of salts. However, the actual T(g) values of the systems were not modified. Thus, the effect of salts on sorption behavior and formation of ice may reflect dynamic water-salt-sugar interactions which take place at a molecular level and are related to the charge/mass ratio of the cation present without affecting supramolecular or macroscopic properties.

Thermophysical properties of trehalose and its concentrated aqueous solutions.

PURPOSE: To address the lack of fundamental thermophysical data for trehalose and its aqueous systems by measuring equilibrium and non-equilibrium properties of such systems. METHODS/RESULTS: Differential scanning calorimetry (DSC) and dynamic mechanical analysis were used to measure glass transition temperatures of trehalose and its solutions. X-ray diffractometry was used to verify the structure of amorphous trehalose. Controlled-stress rheometry was used to measure viscosity of several aqueous trehalose systems at ambient and sub-ambient temperatures. Over this temperature range, the density of these solutions was also measured with a vibrating tube densimeter. The equilibrium phase diagram of aqueous trehalose was determined by measuring the solubility and freezing point depression. CONCLUSIONS: Our solubility measurements, which have allowed long times for attainment of chemical equilibrium, are substantially different from those reported earlier that used different techniques. Our measurements of the glass transition temperature of trehalose are higher than reported values. A simple model for the glass transition is presented to describe our experimental observations.

Puentes translocados / Translocated by-passes

Se presentan 11 puentes translocados de vena safena no invertida para el tratamiento de la arteriopatía obliterante grave de los miembros inferiores. Las ventajas y desventajas de éste procedimiento en relación con la técnica "in situ" son discutidas. Estarían en su favor la utilización ipsi o contralateral de la vena, posibilidad de efectuar un puente secuencial, evitar el problema de la fístula arteriovenosa y de la ocasional endarterectomía de la arteria proximal, efectuar una más cómoda valvulotomía y poder ubicar anatómicamente el by pass sin tensión o angulación en las anastomosis. Los autores comentan particularidades técnicas de la valvulotomía efectuada

Puentes translocados / Translocated by-passes

Se presentan 11 puentes translocados de vena safena no invertida para el tratamiento de la arteriopatía obliterante grave de los miembros inferiores. Las ventajas y desventajas de éste procedimiento en relación con la técnica "in situ" son discutidas. Estarían en su favor la utilización ipsi o contralateral de la vena, posibilidad de efectuar un puente secuencial, evitar el problema de la fístula arteriovenosa y de la ocasional endarterectomía de la arteria proximal, efectuar una más cómoda valvulotomía y poder ubicar anatómicamente el by pass sin tensión o angulación en las anastomosis. Los autores comentan particularidades técnicas de la valvulotomía efectuada (AU)

[Two-dimensional immuno-electrophoresis of cephalospinal fluid proteins wih a study of the IgG/albumin ratio in psychiatry (author's transl)]. / Immunoélectrophorèse bidimensionnelle des protéines du liquide céphalo rachidien (LCR) avec étude du rapport IgG/albumine en psychiatrie.

The purpose of this study (about 187 adult psychiatric patients) is to investigate correlations between "organic brain syndrome" (vascular or abiotrophic) and values of CSF proteins (technique of two-dimensional immunoelectrophoresis). The authors show positive correlations between 'vascular' brain syndrome and increase of one alpha 2 globulin, between 'abiotrophic' brain syndrome and decrease in all globulins, the importance of brain damage and increase of IgG/albumin ratio.

[Clinical significance of the erythro-plasmatic ratio of lithium (author's transl)]. / Signification clinique du rapport érythro-plasmatique du lithium.

Six hundred erythrocyte-plasma lithium ratios have been gathered from 67 patients presenting affective disorders. Ratios values in relapse period are not altered regarding those in remission phase as between periods with neuroleptic associations and those without. Ratios values are not noticeably modified by personality, sex and the evolution of affective disorders. But lithium preventive action is essentially found in patients with high erythrocyte-plasma.