Genetic correlation between serum insulin-like growth factor-1 concentration and performance and meat quality traits in Duroc pigs

This study was intended to examine whether serum IGF-I concentration is appropriate for use as a physiological predictor for genetic improvement of meat production and meat quality traits in pigs. Heritabilities and genetic correlations were estimated for these traits. The Duroc breed used in this study was selected for seven generations for average daily BW gain (DG) from 30 to 105 kg of BW, loin-eye muscle area (EM), backfat thickness (BF), and intramuscular fat (IMF) content. Serum IGF-I concentration of boars and gilts at the fourth generation of selection and that of boars, gilts, and barrows from the fifth to seventh generations of selection were measured at 8 wk (IGFI-8W) for 832 animals and again at the time they reached 105 kg of BW (IGFI-105KG) for 834 animals. A multivariate REML procedure was used to estimate genetic parameters with a model incorporating generation of selection, sex, common environmental effect of litter, and individual additive genetic effects. Heritability estimates for IGFI-8W and IGFI-105KG were 0.23 +/- 0.02 and 0.26 +/- 0.03, respectively. The estimates of common environmental effect for IGFI-8W and IGFI-105KG were 0.20 +/- 0.02 and 0.03 +/- 0.01, respectively. Positive genetic correlations were estimated between IGFI-8W and DG (0.26 +/- 0.08), EM (0.22 +/- 0.10), and IMF (0.32 +/- 0.10). Moreover, the positive genetic correlation between IGFI-105KG and EM was 0.42 +/- 0.08. These results indicate that serum IGF-I concentration at an early stage of growth was effective for prediction of IMF, but it was not a reliable physiological predictor of genetic merit of meat production traits.     

Distribution of photoperiod-insensitive allele Ppd-A1a and its effect on heading time in Japanese wheat cultivars

The Ppd-A1 genotype of 240 Japanese wheat cultivars and 40 foreign cultivars was determined using a PCR-based method. Among Japanese cultivars, only 12 cultivars, all of which were Hokkaido winter wheat, carried the Ppd-A1a allele, while this allele was not found in Hokkaido spring wheat cultivars or Tohoku-Kyushu cultivars. Cultivars with a photoperiod-insensitive allele headed 6.9–9.8 days earlier in Kanto and 2.5 days earlier in Hokkaido than photoperiod-sensitive cultivars. The lower effect of photoperiod-insensitive alleles observed in Hokkaido could be due to the longer day-length at the spike formation stage compared with that in Kanto. Pedigree analysis showed that ‘Purple Straw’ and ‘Tohoku 118’ were donors of Ppd-A1a and Ppd-D1a in Hokkaido wheat cultivars, respectively. Wheat cultivars recently developed in Hokkaido carry photoperiod-insensitive alleles at a high frequency. For efficient utilization of Ppd-1 alleles in the Hokkaido wheat-breeding program, the effect of Ppd-1 on growth pattern and grain yield should be investigated. Ppd-A1a may be useful as a unique gene source for fine tuning the heading time in the Tohoku-Kyushu region since the effect of Ppd-A1a on photoperiod insensitivity appears to differ from the effect of Ppd-B1a and Ppd-D1a.     

Geographical variation of the skull morphology of the common tree shrew (Tupaia glis).

Geographical variation was examined morphologically in the common tree shrew (Tupaia glis) in some Indochinese and Malayan regions. Osteometrical examination and principal component analysis elucidated the morphological differences among various populations. The populations from southern and western Thailand were distinguished morphologically from the other populations. Variation in males from south Thailand and Kuala Lumpur suggests that the Isthmus of Kra may have an influence on the variation of skull morphology. However, the Isthmus of Kra was not completely considered as a factor of geographical separation in this species, because we could not confirm the separation in skull size and shape between the localities at least in females. While, the Kanchanaburi population in western Thailand was significantly smaller than the other population in skull size, and constituted the morphologically separable group in our study.     

Molecular phylogenetic relationship of Tetraodon pufferfish based on mitochondrial DNA analysis

Pufferfishes belonging to the genus Tetraodon form one of the largest groups in the family Tetraodontidae. This group consists of more than 20 species distributed across freshwater, as well as brackish and coastal waters, of Africa and Southeast Asia. However, their phylogenetic and evolutionary relationships are still ambiguous. In the present study, mitochondrial genes encoding 16S rRNA and cytochrome b were sequenced for 17 Tetraodon species collected from various areas mentioned above. Supermatrix analysis based on the complete sequences of the two genes from Tetraodon species was performed using a tree with 50 tetraodontid species (including 7 Tetraodon species) as a backbone. The obtained phylogenetic tree classified Tetraodon species into three groups, correlating well with their habitats, such as Asian freshwater, Asian brackish water, and African freshwater. We also showed that salinity tolerance of Asian freshwater species T. cochinchinensis was apparently lower than that of Asian brackish water species T. nigroviridis, suggesting that the speciation of Tetraodon species in the Asian freshwater group was caused by the molecular evolution associated with osmotic regulation.     

Organ-specific allocation pattern of acquired phosphorus and dry matter in two rice genotypes with contrasting tolerance to phosphorus deficiency

ABSTRACT

Our earlier study demonstrated that the landrace of Japonica rice, Akamai exhibits low-P (phosphorous) tolerance mechanisms compared to the conventional type cultivar, Koshihikari. The present study examined the genotypic difference of yield, plasticity of root growth, and internal utilization of acquired P (allocation pattern of biomass and P among different vegetative and reproductive organs) of two contrasting cultivars in response to P-deficiency. Each cultivar was grown until maturity with (+P) and without (–P) P supply in pots (two plants per pot) filled with 15 kg of Regosol soil. Grain yield and yield components were determined along with biomass and P accumulation in different vegetative and reproductive organs. To assess the plasticity of root growth, the soil column in the pot was divided into two equal portions (upper and lower soil layers) in which the root dry weight and length were measured separately. Among the investigated yield components, the number of filled grains per panicle was the key parameter determining genotypic differences of grain yield of two cultivars. P-deficiency had a marked influence on grain filling of Koshihikari where the filled grain percentage under –P condition was reduced by 29% compared to that under +P condition. However, the respective reduction for Akamai was only 11%. Low-P tolerance ability of Akamai imparts a yield advantage over Koshihikari under P-deficient conditions because of the production of the higher number of filled grains per panicle. Akamai explored both upper and lower soil layers of the pot more efficiently in search of P through greater root biomass and length. Akamai grown under P-deficient conditions had remarkably lower P concentrations in less active vegetative tissues (partly and fully senesced leaves) than those of Koshihikari; whereas, more active organs (green leaves and panicles) contained a greater amount of P. Akamai’s higher plasticity to external P availability can be a genetic resource for developing low-P tolerant, high-yielding rice genotypes suitable for predicted future P-limited environments.     

Gene response in rice plants treated with continuous fog influenced by pH,was similar to that treated with biotic stress

Background

Throughout Asia, including Japan, rice plants are cultivated in a wide range of areas from lowlands to highlands and are frequently exposed to fog, including acid fog. Some physiological studies have shown that acid fog can be a stress factor for plants. We analyzed the gene expression profiles of rice plants treated with artificially prepared simulated acid fog (SiAF) or simulated neutral fog (SiNF) for 1 or 7 days.

Results

Microarray analysis results suggested that both the SiAF and the SiNF treatments induced the expression of genes involved in the defense and stress responses in rice plants. Induction of such genes was detected in plants treated with SiAF for 1 day, and the number of induced genes increased in plants treated with SiAF for 7 days. The genes for defense and stress responses were also induced by SiNF for 7 days, although they were not induced by SiNF for 1 day. The gene expression profiles of the SiAF-treated and the SiNF-treated plants were compared to those of plants treated with other stress factors. The comparison revealed that both SiAF and SiNF treatments have similar effects to biotic stresses and ozone stress. The genes encoding NADPH oxidase and germin, which function in apoplasts, were also induced by SiAF, SiNF and biotic stresses.

Conclusions

These findings suggest that both the SiAF and the SiNF treatments may result in oxidative stress through the apoplastic production of reactive oxygen species.     

Role of Tween 80 in biobleaching of unbleached hardwood kraft pulp with manganese peroxidase

The role of Tween 80 in biobleaching of unbleached hardwood kraft pulp (HWKP) with manganese peroxidase (MnP) was investigated. Among the surfactants (e.g., Tween 80, Tween 20, CHAPSO) the most significant brightness increase was obtained with Tween 80. Tween 80 and Tween 20 exhibited several effects, such as dispersion of degraded lignin and activation of MnP, that partly contributed to the brightening of HWKP during MnP treatment. However, these characteristics did not explain the most appreciable effect on the brightness increase by Tween 80. Lipid peroxidation of surfactants during MnP biobleaching was determined by measuring the peroxide value (POV). The order of the POV increase was consistent with that of the brightness increase of pulp during MnP treatment in the presence of various surfactants or linolenic acid. However, radicals and peroxides derived from lipid (linolenic acid) peroxidation by lipoxidase hardly brightened the HWKP by themselves. These results suggested that Tween 80 was peroxidized by Mn(III), and that Mn(III) and lipid peroxidation of Tween 80 synergistically brightened HWKP.This study was presented in part at the 43rd lignin symposium, Fuchu, Tokyo, Oct. 26–27, 1998 and the 49th annual meeting of the Japan Wood Research Society, Tokyo, April 2–4, 1999     

Cardiac musculature of the cranial and caudal venae cavae and the pulmonary vein in the fowl.

The cardiac musculature of cranial and caudal venae cavae and pulmonary vein was examined to clarify its distribution pattern in the fowl using both light and electron microscopies. The musculature was distributed from the heart to the root of subclavian vein in the cranial vena cava, to the cranial margin of the liver in the caudal vena cava, and to the left and right distal pulmonary veins in the pulmonary vein, respectively. Judging from the morphology and distribution pattern in the venous wall, the cardiac musculature in the fowl is thought to share the same phylogenic origin with that in mammals. The ultrastructure of cardiac myocytes including transitional cells in the cranial vena cava and the pulmonary vein resembled that of atrial myocytes. While, the typical specialized myocytes such as Purkinje fiber were found in the caudal vena cava of the fowl.