Molecular characterization of seven novel Glu-A1^mx alleles from Triticum monococcum ssp. monococcum

Seven Glu-A1m allelic variants of the Glu-A1mx genes in Triticum monococcum ssp. monococcum, designated as 1Ax2.1a, 1Ax2.1b, 1Ax2.1c, 1Ax2.1d, 1Ax2.1e, 1Ax2.1f, and 1Ax2.1g were characterized. Their authenticity was confirmed by successful expression of the coding regions in E. coli, and except for the 1Ax2.1a with the presence of internal stop codons at position of 313 aa, all correspond to the subunit in seeds. However, all the active six genes had a same DNA size although their encoding subunits showed different molecular weight. Our study indicated that amino acid residue substitutions rather than previously frequently reported insertions/deletions played an important role on the subunit evolution of these Glu-A1mx alleles. Since variation in the Glu-A1x locus in common wheat is rare, these novel genes at the Glu-A1mx can be used as candidate genes for further wheat quality improvement

Molecular characterization of different Triticum monococcum ssp. monococcum Glu-A1^mx alleles

High-molecular-weight glutenin subunits (HMW-GSs) are important seed storage proteins associated with bread-making quality in common wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD). Variation in the Glu-A1x locus in common wheat is scare. Diploid Triticum monococcum ssp. monococcum (2n = 2x = 14, AmAm) is the first cultivated wheat. In the present study, allelic variations at the Glu-A1mx locus were systematically investigated in 197 T. monococcum ssp. monococcum accessions. Out of the 8 detected Glu-A1mx alleles, 5 were novel, including Glu-A1m-b, Glu-A1m-c, Glu-A1m-d, Glu-A1m-g, and Glu-A1m-h. This diversity is higher than that of common wheat. Compared with 1Ax1 and 1Ax2*, which are present in common wheat, these alleles contained three deletions/insertions as well as some single nucleotide polymorphism variations that might affect the elastic properties of wheat flour. New variations in T. monococcum probably occurred after the divergence between A and Am and are excluded in common wheat populations. These allelic variations could be used as novel resources to further improve wheat quality

Characterization of an expressed Triticum monococcum Glu-A1y gene containing a premature termination codon in its C-terminal coding region

Premature termination codons (PTCs) are an important reason for the silence of highmolecular- weight glutenin subunits in Triticum species. Although the Glu-A1y gene is generally silent in common wheat, we here isolated an expressed Glu-A1y gene containing a PTC, named 1Ay8.3, from Triticum monococcum ssp. monococcum (AmAm, 2n = 2x = 14). Despite the presence of a PTC (TAG) at base pair positions 1879–1881 in the C-terminal coding region, this did not obviously affect 1Ay8.3 expression in seeds. This was demonstrated by the fact that when the PTC TAG of 1Ay8.3 was mutated to the CAG codon, the mutant in Escherichia coli bacterial cells expressed the same subunit as in the seeds. However, in E. coli, 1Ay8.3 containing the PTC expressed a truncated protein with faster electrophoretic mobility than that in seeds, suggesting that PTC translation termination suppression probably occurs in vivo (seeds) but not in vitro (E. coli). This may represent one of only a few reports on the PTC termination suppression phenomenon in genes

Preparation and tribological properties of Fe-hydroxyapatite bioceramics

Pigmented tooth enamel is generally composed of iron-containing hydroxyapatite (Fe-HA), and thus exhibits high hardness and good wear resistant. In this study, Fe-HA powders were synthesized using ultrasonic-assisted microwave hydrothermal method and the tribological properties of the Fe-HA ceramics were evaluated, aiming to explore the improvement effect of iron element on the wear resistance of nano-hydroxyapatite. The influence of Fe content on the phase composition, crystal structure and morphology of Fe-HA powders were characterized by various microscopy characterizations. Results showed that the Fe content had a substantial influence on the morphology and crystal structure of Fe-HA powders. Compared with the pure HA ceramic, the prepared Fe-HA ceramics showed obviously better wear resistance

Dental development and microstructure of bamboo rat incisors

Bone adapts to habitual loads by remodeling to resist stresses that would otherwise break it. The question of whether the same holds for teeth, however, remains unanswered. We might expect species with ever-growing dentitions to alter enamel histology in response to diet. In this study we fed bamboo rats (Rhizomys sinensis) different foods to assess effects on enamel microstructure. Results indicate that gnawing fracture-resistant items (i.e., bamboo) produces substantively different dental microstructures than does eating less mechanically-challenging ones (i.e., potato). Bamboo induces a structured, anisotropic pattern of rods that strengthens incisor enamel, whereas potato produces less structured, weaker enamel. Blood tests suggest that these differences are not related to nutrient variation. Rather, these ever-growing teeth evidently require a specific mechanical environment to develop normal dental microstructure