A genome‐wide association study for fat‐related traits computed by image analysis in Japanese Black cattle

The objective of this study was to identify genomic regions associated with fat‐related traits using a Japanese Black cattle population in Hyogo. From 1836 animals, those with high or low values were selected on the basis of corrected phenotype and then pooled into high and low groups (n = 100 each), respectively. DNA pool‐based genome‐wide association study (GWAS) was performed using Illumina BovineSNP50 BeadChip v2 with three replicate assays for each pooled sample. GWAS detected that two single nucleotide polymorphisms (SNPs) on BTA7 (ARS‐BFGL‐NGS‐35463 and Hapmap23838‐BTA‐163815) and one SNP on BTA12 (ARS‐BFGL‐NGS‐2915) significantly affected fat percentage (FAR). The significance of ARS‐BFGL‐NGS‐35463 on BTA7 was confirmed by individual genotyping in all pooled samples. Moreover, association analysis between SNP and FAR in 803 Japanese Black cattle revealed a significant effect of SNP on FAR. Thus, further investigation of these regions is required to identify FAR‐associated genes and mutations, which can lead to the development of DNA markers for marker‐assisted selection for the genetic improvement of beef quality.     

Effects of clay on fat necrosis and carcass characteristics in Japanese Black steers

Twenty 10‐month‐old Japanese Black steers were used to evaluate the effects of clay on fat necrosis and carcass characteristics. Ten steers (Clay group) were fed the clay (50 g/day) during 10–30 months of age. The other 10 steers (Control group) were not fed it. There was no significant difference in body weight or average daily gain between the two groups (P > 0.05). The occurrence of fat necrotic mass in the Clay group (30%) was lower (P < 0.05) than that in the Control group (90%) at slaughter. The size of necrotic masses in the Clay group was smaller (P < 0.05) than that in the Control group. There was no significant difference in the marbling score, beef color, Longissimus muscle area or subcutaneous fat thickness between the two groups. These results suggest that the clay prevented the occurrence of fat necrosis and did not affect the carcass characteristics in Japanese Black steers.     

Specific degradation ofβ-aryl ether linkage in synthetic lignin (dehydrogenative polymerizate) by bacterial enzymes ofSphingomonas paucimobilis SYK-6 produced in recombinantEscherichia coli

Sphingomonas paucimobilis SYK-6 produces unique and specific enzymes, such as-etherases,O-demethylases, and ring fission dioxygenases, for lignin degradation. Cleavage of arylglycerol--aryl ether linkage is the most important process in the lignin metabolic pathway ofS. paucimobilis SYK-6. We reported the genes (ligD, ligE, ligF) for enzymes that cleaved-aryl ether linkage of dimeric compounds in previous studies. In this study we synthesized the fluorescent high-molecular-weight lignin (UBE-DHP) by dehydrogenative polymerization. We investigated the-aryl ether cleavage ability of these enzymes produced in recombinantEscherichia coli. When UBE-DHP was incubated with LigF, 4-methylumbeliferone was released as a result of-aryl ether cleavage of O-methylumbelliferyl--hydroxypropiovanillone (compound III) incorporated in UBE-DHP. Here, we report that-etherase ofS. paucimobilis SYK-6 can be expressed inE. coli and is able to cleave the-aryl ether linkage in synthetic high-molecular-weight lignin.     

Ecological studies on subtropical evergreen broad-leaved forest in Okinawa, Japan: Litter production and nutrient input

Patterns of litterfall and nutrient input in a subtropical evergreen broad-leaved forest in northern Okinawa, Japan, were studied during May, 1996–April, 1999. The mean annual rate of litterfall in the five sampling plots ranged from 6.84 to 8.93 Mg ha⁻¹ yr⁻¹, of which 63.3–68.5% were leaves; 22.4–29.1% woody parts (including branches < 5.0 cm in diameter and bark); 2.8–5.0% sexual organs and 4.6–6.3% miscellaneous material. Significant differences were found among plots and among years. Significantly monthly differences pronounced seasonal patterns in litterfall were observed. Total litterfall and leaf litter showed negative correlations with relative basal area of the dominant species,Castanopsis sieboldii; and showed positive correlations with mean height of the stands. The dominant species,C. sieboldii produced an average of 2.36 Mg ha⁻¹ yr⁻¹ of leaf litter, which covered 30.5% of the annual litter production, and the nutrient input from those litterfall contributed 32.3, 28.3, 30.2, 22.2, 32.5, and 30.5% of total N, P, K, Ca, Mg, and Na, respectively. Nutrient use efficiency in litter production was high, especially for P and K compared with other broad-leaved forests in Japan indicating that P and K may be limiting in Okinawan evergreen broad-leaved forest.     

Responses of coppiced Eucalyptus to macro- and micronutrient application

Coppicing is a widely adopted management system for forest plantations; however, little information is available pertaining to responses to fertilizer application. Our objective was therefore to assess the effect of individual and conjunct omissions of N, P, K, Ca, Mg, B, and Cu on the growth of a highly productive Eucalyptus urophylla?×?E. grandis hybrid clone, managed for coppicing at the second rotation, in two soils of contrasting fertility in southeastern Brazil. Two commercial sites of approximately 7 years of age, one in an Arenosol and the other in a Ferralsol, were harvested and the experiments installed. At the Arenosol site, the yield from the fertilizer treatment in the coppice system (R2) was the same as determined for the first rotation (high forest; R1), at approximately 40 m³ ha^?1 year^?1 at 6 years old. In contrast, the yield from the fertilizer treatment in R2 at the Ferralsol site was 11% lower compared with R1. Despite some alterations in leaf nutrient concentrations, other than for K at the Arenosol site (where the K omission treatment reduced wood volume at 6 years by 21%), no yield reduction was found for any no-fertilizer treatments. Due to the widely distributed root system already established in coppiced plantations, ensuring a large volume of soil exploration, coppiced eucalypts only responded to K application. This is due to low soil K availability and the high K demand in eucalypt plantations.

     

Armillaria species in Japan identified by isozyme patterns with special reference to the biological species of the northern hemisphere

Isozyme patterns were examined to characterize biological species ofArmillaria in Japan. Of 25 different enzymes tested, glutamate dehydrogenase (GDH), lactate dehydrogenase (LDH), and aspartate aminotransferase (AAT) showed the most stable and reliable activities. These isozyme patterns showed little variability between haploid and diploid hyphae even under different cultural conditions among isolates tested. From the results, six Japanese biological species were clearly characterized through combination of GDH and LDH isozymes. There were no differences on the whole in isozyme patterns among European biological species ofArmillaria.     

麦冬块根提取物对稻瘟病菌丝及苗期稻瘟病发生的抑制效果

采用不同浓度来自70%甲醇溶液的麦冬块根提取物对2种产自日本的稻瘟病菌生理小种菌株MAFF305480和MAFF101002的菌丝生长及其接种诱发水稻幼苗稻瘟病发生的抑制效果进行评价.试验表明:含有麦冬块根提取物的原液1/10,1/20,1/40以及1/80浓度都能明显抑制稻瘟病菌小种菌株(MAFF305480和MAFF101002)]菌丝生长,抑制率均56.4%以上,对接种诱发稻瘟病的水稻幼苗处理发现,幼苗植株发病级数为明显下降,抑制率均38.4%以上,并且都随着处理浓度提高抑制效果明显提高.研究结果表明,麦冬块根提取物中含有抑制稻瘟病菌生长的化学物质,并且能直接抑制稻瘟病菌发生和生长.     

Quantitative trait loci for rice blast resistance detected in a local rice breeding population by genome-wide association mapping

Plant breeding programs aim to develop cultivars with high adaptability to the specific conditions in a local region. As a result, unique genes and gene combinations have been accumulated in local elite breeding populations during the long history of plant breeding. Genetic analyses on such genes and combinations may be useful for developing new cultivars with more-desirable agronomic traits. Here, we attempted to detect quantitative trait loci (QTL) for rice blast resistance (BR) using a local breeding rice population from Hokkaido, Japan. Using genotyping data on single nucleotide polymorphisms and simple sequence repeat markers distributed throughout the whole genomic region, we detected genetic regions associated with phenotypic variation in BR by a genome-wide association mapping study (GWAS). An additional association analysis using other breeding cultivars verified the effect and inheritance of the associated region. Furthermore, the existence of a gene for BR in the associated region was confirmed by QTL mapping. The results from these studies enabled us to estimate potential of the Hokkaido rice population as a gene pool for improving BR. The results of this study could be useful for developing novel cultivars with vigorous BR in rice breeding programs.     

Phylogenetic analysis of Theileria sp. from sika deer, Cervus nippon, in Japan

The 18S rRNA genes of Theileria species detected in sika deer, Cervus nippon centralis in Yamaguchi and Cervus nippon yesoensis in Hokkaido, were analyzed. The percent identities of the nucleotide sequences of Theileria from Cervus nippon centralis and Cervus nippon yesoensis were more than 99%. The percent identities of the Theileria sp. from sika deer and Theileria sergenti, Theileria buffeli and Theileria cervi were 97, 96 and 95%, respectively. Phylogenetic analysis of the gene sequences also revealed that Theileria sp. detected from sika deer comprise a clade that is clearly distinct from the clade comprised of Theileria from cattle.