Phenotypic biodiversity of an endemic wild pear, Pyrus mamorensis Trab., in North-Western Morocco using morphological descriptors

In this paper, we report on morphological diversity, ecology and flowering phenological records of an endangered and an endemic species of Morocco Pyrus mamorensis Trab. For this study, a survey was undertaken in North-Western Morocco (Mamora forest and Zaër region) whereby 67 accessions of P. mamorensis were sampled. A set of 33 genotypes of Pyrus spp. from the international collection INRA-Angers (France) of the genus Pyrus were also analyzed. The variability of the total of 100 accessions was assessed by twenty-six characters including fourteen qualitative and twelve quantitative traits. The results demonstrated high levels of morphological variation in the sampled accessions of P. mamorensis and established the relationships among the local germplasm using the UPGMA cluster analysis and the factorial discriminant analysis. Furthermore, we were able to distinguish three types of flowering in the Mamora forest: early, intermediate and late flowering type. Otherwise, the UPGMA classification comparing local accessions of P. mamorensis to the international collection led to the formation of four major groups showing the closest correspondence to their geographical origins: (1) The North African species represented by P. mamorensis, (2) The East Asian pea species, (3) The West Asian species and (4) The European species. These findings suggest the importance of implementing a conservation strategy preserving the genetic resources of wild pear in North-Western Morocco.     

Black carbon estimation in French calcareous soils using chemo‐thermal oxidation method

We studied the black carbon (BC) content of ca. 405 samples from French topsoil and artificial soil and carbonate mixtures. Our protocol involved three main steps: (i) decarbonation by HCl, (ii) elimination of non‐pyrogenic organic carbon in a furnace at 375 °C, and (iii) quantification of residual carbon by CHN analysis. BC content increased for calcareous soils according to their carbonates content. Subsequent analyses confirmed the existence of a methodological artefact for BC determination only in calcareous soils. Decarbonation changes the thermal properties of organic matter, creating more recalcitrant carbon than in the initial sample. Higher CaCO₃ and organic carbon content results in a more pronounced artefact. The reversal of the first two steps of the chemo‐thermal oxidation method (i.e. thermal oxidation before soil decarbonation) eliminates this artefact. Overall, our results suggest that BC content may have been overestimated in a large number of studies on calcareous soils.     

Regulation and function of AtNRAMP4 metal transporter protein

The NRAMP gene family encodes integral membrane proteins mediating the transport of a broad range of transition metals in bacteria, fungi, plants, and animals. We studied the regulation of AtNRAMP4 in Arabidopsis. In a previous study, we showed that AtNRAMP3 and AtNRAMP4 transport manganese (Mn), iron (Fe), and cadmium (Cd). In this study, we show that, in contrast to AtNRAMP3, AtNRAMP4 complements the growth phenotype of the zrt1zrt2 Zn uptake deficient yeast mutant. In a previous study, we have shown that, under Fe starvation, AtNRAMP4 mRNA levels are up-regulated in Arabidopsis. To analyze the regulation of AtNRAMP4 at the protein level, we generated specific antibodies against AtNRAMP4 protein. The antiserum was able to recognize a tagged version of AtNRAMP4 expressed in yeast. The antibody did not reveal any change in AtNRAMP4 protein level upon Fe starvation in Arabidopsis thaliana ecotype Columbia plants. In AtNRAMP4 overexpressing plants, high levels of AtNRAMP4 protein could be detected. AtNRAMP4 overexpressing plants display cadmium hypersensitivity in a medium containing 50 μm FeEDTA as Fe source. However, despite the constitutive accumulation of AtNRAMP4 protein, AtNRAMP4 over-expressing plants did not display Cd hypersensitivity under high Fe supply (100 μm FeHBED). AtNRAMP4 over-expressing lines displayed the same sensitivity to Zn as controls under all conditions tested. Our results suggest a translational level for the regulation of AtNRAMP4. Over-expression of AtNRAMP4 in Arabidopsis thaliana confers a slight hypersensitivity to Cd but not to Zn.     

串联启动子调控下的t-PAcDNA乳腺定位表达

由牛β-Casein启动子与大鼠WAP启动子串联构建了t-PAcDNA乳腺定位表达载体pSVL-WAPβ-PA，将3种表达载体pSVL-βb-PA,pSVL-WAP-PA及pSVL-WAPβ-PA分别注入怀孕家兔乳腺导管中，溶圈试验结果显示，3种表达载体均能在家兔乳腺中表达，且以分娩后第4d的乳汁中表达水平最高，分别为390，440，450ug.L^-1，本试验为进一步研究t-PA基因乳腺定位表达调控和建立t-PA乳腺生物反应器奠定了基础。     

UV-visible spectroscopic investigation of the 8,8-methylmethine catechin-malvidin 3-glucoside pigments in aqueous solution: structural transformations and molecular complexation with chlorogenic acid

The physicochemical properties of 8,8-methylmethine catechin-malvidin 3-O-glucoside isomers, commonly referred to as catechin-ethyl-malvidin 3-O-glucoside, have been studied in aqueous solutions and compared with those of the parent anthocyanin (malvidin 3-O-glucoside). The hydration and acidity constants (pKh and pKa) of the catechin-ethyl-malvidin 3-O-glucoside pigments and malvidin 3-O-glucoside were determined by UV-visible spectroscopic measurements. The ethyl-linked catechin-malvidin 3-O-glucoside pigments present higher stability toward hydration than the parent anthocyanin. The high resistance of these ethyl-linked pigments toward the hydration is related to the self-association that offers optimal protection from the nucleophilic attack of water. Moreover, the ethyl link may confer to the molecule enough flexibility to undergo intramolecular interaction, further protecting it from hydration and bisulfite discoloration. In the wine pH range (3.2-4.0), due to the low pKa and high pKh values, the ethyl-linked pigments are present as colored forms (flavylium cation and quinonoid bases).     

Characterization of dinucleotide and trinucleotide EST-derived microsatellites in the wheat genome

Over the past decade microsatellites or simple sequence repeats (SSRs) have attracted a considerable amount of attention from researchers. The aim of the present paper was to analyse expressed sequence tag-derived SSR (EST-SSR) marker variability in wheat and to investigate the relationships between the number and type of repeat units and the level of microsatellite polymorphism. Two hundred and forty-one new EST-SSR markers available in a public database () were characterized in eight durum wheat cultivars (Svevo, Ciccio, Primadur, Duilio, Meridiano, Claudio, Latino, Messapia), two accessions of Triticum turgidum var. dicoccoides (MG4343, MG29896), one accession of T. turgidum var. dicoccum (MG5323) and in the common wheat cv. Chinese Spring. Of these, 201 primer pairs (83.4%) amplified PCR products successfully, while the remaining 40 (16.6%) failed to amplify any product. Of the EST-SSRs analysed, 45.2% of the primer pairs amplified one or two PCR products. Multiple discrete PCR products were observed among both di- and trinucleotide EST-SSR markers (31.2 and 40.5%, respectively). Markers based on dinucleotide microsatellites were more polymorphic than those based on trinucleotide SSRs in the 12 wheat genotypes tested (68.9 and 52.7%, respectively). An average of 2.5 alleles for dinucleotide and 2.0 alleles for trinucleotide SSRs was observed. The data reported in the present work indicate the presence of a significant relationship between motif sequence types and polymorphism. The primer set based on the AG repeat motif showed the lowest percentage of polymorphism (55.0%), while the primer set based on the AC repeat motif showed t he highest percentage (85.0%). Among trinucleotide SSRs, the AGG microsatellite markers showed the highest percentage of polymorphism (70.0%), and the ACG motif the lowest value (25.0%). The characterization of these new EST-SSR markers and the results of our studyon the effect of repeat number and type of motifs could have important applications in the genetic analysis of agronomically important traits, quantitative trait locus discovery and marker-assisted selection.