Age‐related changes in the bovine corpus luteum function and progesterone secretion

Decreased fertility associated with maternal ageing is a well‐known critical problem, and progesterone (P4) concentration decreases during the menopause transition in women. The corpus luteum (CL) secretes P4, thereby supporting the implantation and maintenance of pregnancy. It is proposed that a bovine model is suitable for studying age‐associated decline of fertility in women because the physiology of cows is similar to that of women and cows have a greater longevity compared with other animal models. Thus, we investigated the age‐dependent qualitative changes and inflammatory responses in the bovine CL. In vivo experiment: Cows were divided into three groups, namely, young (mean age: 34.8 months), middle (80.1 months) and aged (188.9 months). Blood samples were collected on days 7 and 12 during the estrous cycle. In vitro experiments: Cows were divided into young (mean age: 27.6 months) and aged (183.1 months). The CL tissues of these groups were collected from a local slaughterhouse and used for tissue culture experiments. An in vivo experiment, plasma P4 concentration in aged cows was significantly lower than that in young cows, whereas no difference was found regarding the area of CL. An in vitro examination in the bovine CL tissues showed that the luteal P4 concentration, P4 secretion, and mRNA expression of StAR and 3β‐HSD were lower in aged cows compared with young cows, especially in the early luteal phase. However, no differences were detected in the mRNA expression of inflammation‐ and senescence‐related factors and inflammatory responses to lipopolysaccharides between the CL tissues from young and aged cows, indicating that an age‐dependent increase in inflammation is not involved in the luteal function. P4 production and secretion from the bovine CL diminish in old cows, especially during the early luteal phase, suggesting that senescence may affect the luteal function in cows.     

Establishment of bipotent progenitor cell clone from rat skeletal muscle

The present study describes the isolation, cloning and characterization of adipogenic progenitor cells from rat skeletal muscle. Among the obtained 10 clones, the most highly adipogenic progenitor, 2G11 cells, were further characterized. In addition to their adipogenicity, 2G11 cells retain myogenic potential as revealed by formation of multinucleated myotubes when co‐cultured with myoblasts. 2G11 cells were resistant to an inhibitory effect of basic fibroblast growth factor on adipogenesis, while adipogenesis of widely used preadipogenic cell line, 3T3‐L1 cells, was suppressed almost completely by the same treatment. In vivo transplantation experiments revealed that 2G11 cells are able to possess both adipogenicity and myogenicity in vivo. These results indicate the presence of bipotent progenitor cells in rat skeletal muscle, and suggest that such cells may contribute to ectopic fat formation in skeletal muscle.     

Mapping QTL for fat area ratios and serum leptin concentrations in a Duroc purebred population

The reduction of extra subcutaneous, intermuscular and abdominal fat is important to increase the carcass lean percentage of pigs. Image analyses of fat area ratios were effective for estimation of separated fat in pig carcasses. Serum concentrations of leptin are useful as physiological predictors of fat accumulation in pigs. The objectives of the present study were to perform a quantitative trait locus (QTL) analysis for fat area ratios and serum leptin concentrations in a Duroc purebred population. Pigs (n = 226 to 538) were measured for fat area ratios of carcass cross‐sections at the fifth to sixth thoracic vertebrae, half body length and last thoracic vertebra using an image analysis system, and serum leptin concentration. In total, animals were genotyped for 129 markers and used for QTL analysis. For fat area ratios, four significant and 12 suggestive QTLs were detected on chromosomes 1, 6, 7, 8, 9, 12 and 13. Significant QTLs were detected on the same region of chromosome 6, which was located near a leptin receptor gene. For serum leptin concentrations, two significant and two suggestive QTLs were detected on chromosomes 6, 9, and 16, and the QTLs on chromosome 6 were also in the same region for fat area ratios.     

Common nucleotide sequence of structural gene encoding fibroblast growth factor 4 in eight cattle derived from three breeds

Fibroblast growth factor 4 (FGF4) is considered as a crucial gene for the proper development of bovine embryos. However, the complete nucleotide sequences of the structural genes encoding FGF4 in identified breeds are still unknown. In the present study, direct sequencing of PCR products derived from genomic DNA samples obtained from three Japanese Black, two Japanese Shorthorn and three Holstein cattle, revealed that the nucleotide sequences of the structural gene encoding FGF4 matched completely among these eight cattle. On the other hand, differences in the nucleotide sequences, leading to substitutions, insertions or deletions of amino acid residues were detected when compared with the already reported sequence from unidentified breeds. We cannot rule out a possibility that the structural gene elucidated in the present study is widely distributed in cattle. To the best of our knowledge, this is the first determination of the complete nucleotide sequence of the structural gene encoding bovine FGF4 in identified breeds.     

Allelopathy of pinecone in Japanese red pine tree (Pinus densiflora Sieb. et Zucc.)

There are fewer weeds in the ground covered with pinecones of Japanese red pine trees ( Pinus densiflora Sieb. et Zucc.) than in the ground without pinecones. When six species of seeds were cultured with Japanese red pinecones on agar, the growth of cress, lettuce and cat's eye were inhibited. Pinecones had a plant species-selective influence on their growth. Exudates of the pinecones showed high biological activity and also plant species-selective activity. Some species-selective allelopathic substances may be released from the pinecones. One of the inhibiting allelopathic substances was isolated from the exudates of the pinecones using a bioassay of cat's eye. The substance was identified as phenylacetic acid from an ESI-MS and ¹H NMR spectra. It inhibited shoot and radicle elongation of cat's eye at concentrations of 30–100 p.p.m. The substance was also isolated from an agar medium after removal of the pinecones. These results suggest that pinecones may inhibit some weeds that grow around pine trees. There are many reports of the allelopathic effect of leaves, bark and roots of many plants, however, this is the first report that reveals the cone also affects the allelopathy phenomenon in Japanese red pine trees.     

Functional Analysis of an ATP-Binding Cassette Transporter Gene in Botrytis cinerea by Gene Disruption

The BMR1 gene encoding an ABC transporter was cloned from Botrytis cinerea. To examine the function of BMR1 in B. cinerea, we isolated BMR1-deficient mutants after gene disruption. Disruption vector pBcDF4 was constructed by replacing the BMR1-coding region with a hygromycin B phosphotransferase gene (hph) cassette. The BMR1 disruptants had an increased sensitivity to polyoxin and iprobenfos. Polyoxin and iprobenfos, structurally unrelated compounds, may therefore be substrates of BMR1. Received 18 December 2000/ Accepted in revised form 18 April 2001     

Basic characterization of 90 kDa heat shock protein genes HSP90AA1, HSP90AB1, HSP90B1 and TRAP1 expressed in Japanese quail (Coturnix japonica)

In the current study, we describe four novel members of the 90 kDa heat shock protein (HSP90) family expressed in Japanese quail, Coturnix japonica. The coding regions of the genes, CjHSP90AA1, CjHSP90AB1, CjHSP90B1 and CjTRAP1, exhibited more than 94% similarity to their related genes in chicken. The putative proteins encoded by these quail genes contained motifs considered essential for HSP90 gene function. In addition, the predicted proteins were more similar to HSP90AA1, HSP90AB1, HSP90B1 and TRAP1 proteins expressed in vertebrates than they were to other members of the HSP90 family. Exon numbers of CjHSP90AA1 (11), CjHSP90AB1 (12) or CjTRAP1 (18) are the same as the chicken and mammalian orthologs. Furthermore, gene order in the regions surrounding CjHSP90AB1 and CjTRAP1 has been preserved, providing evidence that the genomic regions were orthologous to HSP90‐containing regions in the chicken genome. The promoter regions of the genes also contained conserved motifs identified in related genes of chicken. However, the nucleotide sequences of the 5′‐flanking region of these genes were highly polymorphic. We also found that CjHSP90AA1 exhibited a robust response to heat shock treatment. Taken together, the data suggest that CjHSP90AA1, CjHSP90AB1, CjHSP90B1 and CjTRAP1 encode orthologs of HSP90AA1, HSP90AB1, HSP90B1 and TRAP1, respectively.