We investigate the effect of hydrogen on morphological changes in GaN columns grown by electron–cyclotron-resonance plasma-excited molecular beam epitaxy on sapphire (0
0
0
1) substrates. In GaN ...growth with a hydrogen flow of 6
sccm, hexagonal columnar structure was obtained. Morphological changes of the GaN columns from hexagonal to triangle were observed by increasing the hydrogen flow rate. It is considered to be caused by preferential growth along three of the six
〈1
0
1
̄
0〉
directions. The surface of the triangle columns consisted of
{1
0
1
̄
3}
and
{1
0
1
̄
1}
faceted planes. Formation mechanism of the triangle columnar structure is discussed.
Summary
Bovine MX1 cDNAs consisting of 2280 bp from 11 animals of five breeds and from a cultured cell line were sequenced and compared with previously reported data. Ten nucleotide substitutions ...were synonymous mutations, and a single nucleotide substitution at 458 resulted in an amino acid exchange of Ile (ATT) and Met (ATG). A 13‐bp deletion–insertion mutation was also found in the 3′‐UTR. Based on the nucleotide substitutions found in this study, bovine MX1 cDNA was classified into 11 genotypes. A phylogenetic tree of the 11 genotypes suggested that the genotypes observed in Brahman were a great genetic distance from other genotypes. An 18‐bp deletion–insertion variation at position 171 was found to be the result of alternative splicing. The 18‐bp deletion–insertion is located at the boundary between exon 3 and intron 3. Permanently transfected 3T3 cell lines expressing bovine MX1 mRNA were established to analyse the antiviral potential against VSVΔG*‐G infection. Transfected cell clones expressing bovine MX1 mRNA showed a significantly smaller number of cells infected with VSVΔG*‐G compared with the control cells. These results indicate that the bovine MX1 protein has potent antiviral activity.
The semen production traits of bulls from 2 major cattle breeds in Japan, Holstein and Japanese Black, were analyzed comprehensively using genome-wide markers. Weaker genetic correlations were ...observed between the 2 age groups (1 to 3 yr old and 4 to 6 yr old) regarding semen volume and sperm motility compared with those observed for sperm number and motility after freeze-thawing. The preselection of collected semen for freezing had a limited effect. Given the increasing importance of bull proofs at a young age because of genomic selection and the results from preliminary studies, we used a multipletrait model that included motility after freeze-thawing with records collected at young ages. Based on variations in contemporary group effects, accounting for both seasonal and management factors, Holstein bulls may be more sensitive than Japanese Black bulls to seasonal environmental variations; however, the seasonal variations of contemporary group effects were smaller than those of overall contemporary group effects. The improvement of motilities, recorded immediately after collection and freeze-thawing, was observed in recent years; thus, good management and better freeze-thawing protocol may alleviate seasonal phenotypic differences. The detrimental effects of inbreeding were observed in all traits of both breeds; accordingly, the selection of candidate bulls with high inbreeding coefficients should be avoided per general recommendations. Semen production traits have never been considered for bull selection. However, negative genetic trends were observed. The magnitudes of the estimated h2 were comparable to those of other economically important traits. A single-step genomic BLUP will provide more accurate predictions of breeding values compared with BLUP; thus, marker genotype information is useful for estimating the genetic merits of bulls for semen production traits. The selection of these traits would improve sperm viability, a component related to breeding success, and alleviate negative genetic trends.
The bovine Mx1 promoter region was found to contain 4 IFN-stimulated response elements (ISREs), 7 GC boxes, 2 IL-6 responsive elements, 2 NFκB-binding sites and 2 AP-1-binding sites. Among Holstein, ...Charolai, and Brahman breeds, 5 nucleotide substitutions were detected in the promoter region. After the Mx1 promoter region from Holstein had been constructed with pGL-basic expression vector, the transfected cells showed promoter activity after IFN induction. Several artificial deletion mutants were prepared to determine the important regulatory elements responsible for the promoter activity, and it was found that ISRE has a key function in IFN response. The proximal ISRE1 showed potential induction by IFN. Furthermore, the proximal GC boxes were found to be essential for IFN response in the bovine Mx1 promoter with the deletion mutants. In this case, the 2 GC boxes exhibited a synergistic activation in the IFN response. Mithramycin A, an agent that inhibits gene expression selectively by coating GC boxes, was used, and Mx mRNA expression in MDBK cells was suppressed by this chemical. Therefore, GC boxes were also shown to be essential for IFN response in the bovine Mx1 gene.
