Characterization of ethylene biosynthesis and its regulation during fruit ripening in kiwifruit,Actinidia chinensis ‘Sanuki Gold’

Ethylene biosynthesis in kiwifruit, Actinidia chinensis ‘Sanuki Gold’ was characterized using propylene, an ethylene analog, and 1-methylcyclopropene (1-MCP), an inhibitor of ethylene perception. In fruit harvested between a young stage (66 days after pollination) (DAP) and an early commercial harvesting stage (143 DAP), 2 days of exposure to propylene were sufficient to initiate ethylene biosynthesis while in fruit harvested at commercial harvesting stage (154 DAP), 4 days of propylene treatment were required. This observation suggests that response of ethylene biosynthesis to propylene treatment in kiwifruit declined with fruit maturity. Propylene treatment resulted in up-regulated expression of AC-ACO1, AC-ACO2, AC-SAM1 and AC-SAM2, prior to the induction of AC-ACS1 and ethylene production, confirming that AC-ACS1 is the rate limiting step in ethylene biosynthesis in kiwifruit. Treatment of fruit with more than 5 μL L^?1 of 1-MCP after the induction of ethylene production subsequently suppressed ethylene production and expression of ethylene biosynthesis genes. Treatment of fruit with 1-MCP at harvest followed with propylene treatment delayed the induction of ethylene production and AC-ACS1 expression for 5 days. These observations suggest that in ripening kiwifruit, ethylene biosynthesis is regulated by positive feedback mechanism and that 1-MCP treatment at harvest effectively delays ethylene production by 5 days.     

Effect of natural and synthetic retinoids on the proliferation and differentiation of three canine melanoma cell lines

The effect of two natural retinoids and synthetic retinoids with or without retinoid synergists on the proliferation and differentiation of 3 melanoma cell lines were investigated in vitro. No retinoids showed significant growth inhibitory effect on these cell lines when used alone, however, cell differentiation and significant growth inhibition were observed when treated with a combination of retinoids and a retinoid synergist. This study may suggest that, though the cells showed low susceptibilities when retinoids were treated alone, the combination of retinoids and a retinoid synergist may be effective to control the growth of canine melanoma cell lines.     

Slipping magnetic reconnection in coronal loops

Magnetic reconnection of solar coronal loops is the main process that causes solar flares and possibly coronal heating. In the standard model, magnetic field lines break and reconnect instantaneously at places where the field mapping is discontinuous. However, another mode may operate where the magnetic field mapping is continuous but shows steep gradients: The field lines may slip across each other. Soft x-ray observations of fast bidirectional motions of coronal loops, observed by the Hinode spacecraft, support the existence of this slipping magnetic reconnection regime in the Sun's corona. This basic process should be considered when interpreting reconnection, both on the Sun and in laboratory-based plasma experiments.     

Genotypes and allele frequencies of buried SNPs in a bovine single‐nucleotide polymorphism array in Japanese Black cattle

Single nucleotide polymorphism (SNP) arrays are widely used for genetic and genomic analyses in cattle breeding; thus, data derived from SNP arrays have accumulated on a large scale nationwide. Commercial SNP arrays contain a considerable number of unassigned SNPs on the chromosome/position on the genome; these SNPs are excluded in subsequent analyses. Notably, the position‐unassigned SNPs, or “buried SNPs” include some of the markers associated with genetic disease. In this study, we identified the position of buried SNPs using the Basic Local Alignment Search Tool against the surrounding sequences and characterized the relationship between SNPs and genetic diseases in Online Mendelian Inheritance in Animals based on the genomic position. We determined the position of 285 buried SNPs on the genome and surveyed the genotype and allele frequencies of these SNPs in 5,955 individual Japanese Black cattle. Eleven SNPs associated with genetic disease, which contained five buried SNPs, were found in the population with the risk allele frequency ranging from 0.00008396 to 0.46. These results indicate that buried SNPs in the bovine SNP array can be utilized to identify associations with genetic disorders from large scale accumulated SNP genotype data in Japanese Black cattle.     

cDNA cloning of goldfish Hsp27 and its chaperone activity

A cDNA fragment encoding goldfish Hsp27 was amplified by polymerase chain reaction and its nucleotide sequence was determined. The deduced amino-acid sequence of goldfish Hsp27 showed 58–62% identity to Hsp27 from other vertebrates. Three serine residues reported to be phosphorylated in human Hsp27 were conserved in goldfish Hsp27. The Hsp27 gene was transcribed in goldfish culture cells after temperature shift from 20°C to 40°C, but not from 20°C to 35°C. Recombinant goldfish Hsp27 was examined for its in vitro chaperone activity and compared to those of Hsp30 from the same fish and human recombinant Hsp27. Goldfish Hsp27 and Hsp30 showed a similar activity at 10 μM, which was significantly lower than that of human Hsp27. At 1 and 5 μM concentrations, however, goldfish Hsp27 showed slightly lower activity than goldfish Hsp30, but the activities of both goldfish proteins still remained significantly lower than that of human Hsp27. Meanwhile, goldfish Hsp27 formed oligomer, which was slightly smaller than that of Hsp30. These results suggest that goldfish Hsp27 contributes as a molecular chaperone in association with Hsp30 to compensate for stress resulting from rapid temperature fluctuations. The nucleotide sequence reported in this paper has been registered into the DDBJ/EMBL/GenBank databases with accession number AB239443 for goldfish Hsp27.     

Expression analysis of defense-related genes in wild kiwifruit (Actinidia rufa) tolerant to bacterial canker

Journal of General Plant Pathology - Kiwifruit bacterial canker, which is caused by Pseudomonas syringae pv. actinidiae biovar 3 (Psa3), is found throughout kiwifruit-growing countries. Here, we...     

Genetic diversity and genomic inbreeding in Japanese Black cows in the islands of Okinawa Prefecture evaluated using single-nucleotide polymorphism array

Maintaining genetic diversity and inbreeding control are important in Japanese Black cattle production, especially in remote areas such as the islands of Okinawa Prefecture. Using a single-nucleotide polymorphism (SNP) array, we evaluated the genetic diversity and genomic inbreeding in Japanese Black cows from the islands of Okinawa Prefecture and compared them to those from other locations across Japan. Linkage disequilibrium decay was slower in cows in the islands of Okinawa Prefecture. The estimated effective population size declined over time in both populations. The genomic inbreeding coefficient (F_ROH) was estimated using long stretches of consecutive homozygous SNPs (runs of homozygosity; ROH). F_ROH was higher in the cows on the islands of Okinawa Prefecture than on other locations. In total, 818 ROH fragments, including those containing NCAPG and PLAG1, which are major quantitative trait loci for carcass weight in Japanese Black cattle, were present at significantly higher frequencies in cows in the islands of Okinawa Prefecture. This suggests that the ROH fragments are under strong selection and that cows in the islands of Okinawa Prefecture have low genetic diversity and high genomic inbreeding relative to those at other locations. SNP arrays are useful tools for evaluating genetic diversity and genomic inbreeding in cattle.     

The expression of sialyl Lewis X in canine and feline mammary gland tumors

The expression of sialyl Lewis X (sLe(x)) in 93 canine and 15 feline mammary gland tumors (MGT) obtained by surgical resection at Veterinary Medical Center, the University of Tokyo was examined by immunohistochemistry. Their clinicopathological features and prognosis were also reviewed. Approximately 60% of MGT tissues showed sLe(x) positive expressions, while all normal mammary gland tissues were negative. However, its expression was not correlated with clinicopathological features and prognosis significantly. This study suggests that sLe(x) may be a tumor-associated antigen in canine and feline MGTs.     

Fine thermal structure of a coronal active region

The determination of the fine thermal structure of the solar corona is fundamental to constraining the coronal heating mechanisms. The Hinode X-ray Telescope collected images of the solar corona in different passbands, thus providing temperature diagnostics through energy ratios. By combining different filters to optimize the signal-to-noise ratio, we observed a coronal active region in five filters, revealing a highly thermally structured corona: very fine structures in the core of the region and on a larger scale further away. We observed continuous thermal distribution along the coronal loops, as well as entangled structures, and variations of thermal structuring along the line of sight.