Cytogenetic and molecular identification of a wheat-Leymus mollis alien multiple substitution line from octoploid Tritileymus x Triticum durum.

Leymus mollis (Trin.) Pilger (NsNsXmXm, 2n = 28), a wild relative of common wheat, possesses many traits that are potentially valuable for wheat improvement. In order to exploit and utilize the useful genes of L. mollis, we developed a multiple alien substitution line, 10DM50, from the progenies of octoploid Tritileymus M842-16 x Triticum durum cv. D4286. Genomic in situ hybridization analysis of mitosis and meiosis (metaphase I), using labeled total DNA of Psathyrostachys huashanica as probe, showed that the substitution line 10DM50 was a cytogenetically stable alien substitution line with 36 chromosomes from wheat and three pairs of Ns genome chromosomes from L. mollis. Simple sequence repeat analysis showed that the chromosomes 3D, 6D, and 7D were absent in 10DM50. Expressed sequence tag-sequence tagged sites analysis showed that new chromatin from 3Ns, 6Ns, and 7Ns of L. mollis were detected in 10DM50. We deduced that the substitution line 10DM50 was a multiple alien substitution line with the 3D, 6D, and 7D chromosomes replaced by 3Ns, 6Ns, and 7Ns from L. mollis. 10DM50 showed high resistance to leaf rust and significantly improved spike length, spikes per plant, and kernels per spike, which are correlated with higher wheat yield. These results suggest that line 10DM50 could be used as intermediate material for transferring desirable traits from L. mollis into common wheat in breeding programs.

A novel SCAR marker for detecting Psathyrostachys huashanica Keng chromatin introduced in wheat.

In this study, we cloned and sequenced a 938-base pair polymorphic band, pHs27, in the tightly linked random amplified polymorphic DNA marker OPU10 and converted it into a sequence-characterized amplified region (SCAR) marker referred to as RHS141, which was specific for the Ns genome of Psathyrostachys huashanica. A GenBank basic local alignment search tool search showed that the sequence of pHs27 had no primary sequence homology with known sequences, and Southern blotting confirmed this result. This SCAR marker was used to detect Ns genome chromatin in wheat, and it was successfully amplified in P. huashanica itself, a complete set of wheat-P. huashanica disomic addition lines (1Ns-7Ns), and undetermined homoeologous group addition lines. This SCAR marker will be a powerful tool for the marker-assisted selection of P. huashanica chromosome(s) in a wheat background, and it should also allow wheat breeders to screen for the excellent traits found in P. huashanica chromatin.

Single nucleotide polymorphisms of the bovine VEGF-B gene and their associations with growth traits in the Nanyang cattle breed.

PCR-SSCP and DNA sequencing methods were applied to reveal single nucleotide polymorphisms (SNPs) in the bovine VEGF-B gene in 675 samples belonging to three native Chinese cattle breeds. We found 3 SNPs and a duplication NC_007330.5: g. [782 A>G p. (Gly112 =) (;) 1000-1001dup CT (;) 1079 C>T (;) 2129 G>A p. (Arg184Gln)]. We also observed a statistically significant association of the polymorphism (1000-1001dup CT) in intron 3 of the VEGF-B gene with the body weight of the Nanyang cattle (p < 0.05). This polymorphisms of VEGF-B gene need to be verified among a larger cattle population before it can be identified as a marker for bovine body weight.

Lack of association of single nucleotide polymorphisms of the bovine Flt-1 gene with growth traits in Chinese cattle breeds.

We analyzed 20 exons, with their intron-exon boundaries, of the bovine Flt-1 gene, using a strategy combining PCR amplification and single-strand conformational polymorphism analysis (PCR-SSCP), followed by nucleotide sequence analysis, in 675 cattle. We then looked for associations between polymorphisms and growth traits. Twelve novel SNPs (ss#184956516, ss#184956517, ss#184956518, ss#184956519, ss#251343993, ss#251343994, ss#251343995, ss#251343996, ss#251343997, ss#251343998, ss#251343999, and ss#251344000) were detected in the bovine Flt-1 gene in all three breeds. We observed no significant associations between these polymorphisms and birth weight, body weight and average daily gain during different growth periods (6, 12, 18, and 24 months old) (P > 0.05), or in body height, body length, heart girth, or height at the hip in Nanyang cattle breeds.

[The kinetics of ascorbic acid oxidation catalyzed by Cu(II)/H2DCA in the presence of DNA].

In phosphate buffer (pH 7.40), at 20.00 +/- 0.05 degrees C, the visible spectra of Cu(II) and Cu(II) complexes and the kinetics of ascorbic acid oxidation catalyzed by Cu(II)/H2DCA in the presence of DNA were studied. Measurements were reported on rate of .OH formation by the oxidation of ascorbic acid in the presence of Cu(II)/H2DCA. It showed that ternary complex Cu(II)/H2DCA/DNA may exist in the system in which DNA strand was broken by ascorbic acid in the presence of Cu(II)/H2DCA, and it was assumed that the DNA-breaking action of ascorbic acid in the presence of Cu(II)/H2DCA conformed to site-specific Fenton reaction mechanism. All the result of DNA-breaking action can be explained in terms of this site-specific Fenton reaction mechanism.

[DNA-breaking action of ascorbic acid in the presence of Cu(II)/demethylcantharic acid complex].

Effects of various factors on the DNA-breaking action of ascorbic acid in the presence of Cu(II)/demethylcantharic acid complex were studied in phosphate buffer (pH 7.40), at 37.0 +/- 0.1 degrees C. It was shown that .OH produced from Fenton reaction of H2O2 which can be formed from the oxidation of ascorbic acid was responsible for the DNA-breaking action of ascorbic acid and the simple Fenton reaction cannot explain all the results.

[Effect of diglycylhistidine on the oxidation of ascorbate catalyzed by Cu(II)].

Glycylglycylhistidine (GGH) was synthesized using mixed anhydride method, and Cu(II): GGH = 1:1 complex was identified using UV, ESR, CD, ORD and FAB/MS technique. The oxidation of ascorbate catalyzed by cupric ion in RPMI 1640 medium (pH 7.40) was studied. The activation energy E = 39.2 kJ/mol. The addition of GGH inhibited the oxidation of ascorbate catalyzed by cupric ion. The investigations with ESR and fluorimetry indicate that there are Cu(I), ascorbate radical (AH), O2-., H2O2 and .OH during the oxidation.