Expression of matrix metalloproteinases in bovine luteal cells induced by prostaglandin F2α, interferon γ and tumor necrosis factor α

We recently demonstrated that luteal cells flow out from the ovary via lymphatic vessels during luteolysis. However, the regulatory mechanisms of the outflow of luteal cells are not known. Matrix metalloproteinases (MMPs) can degrade the extracellular matrix and basal membrane, and tissue inhibitors of matrix metalloproteinases (TIMPs) inhibit the activity of MMPs. To test the hypothesis that MMP expression in luteal cells is regulated by luteolytic factors, we investigated the effects of prostaglandin F2α (PGF), interferon γ (IFNG) and tumor necrosis factor α (TNF) on the mRNA expression of MMPs and TIMPs in cultured luteal cells. Luteal cells obtained from the CL at the mid-luteal stage (days 8–12 after ovulation) were cultured with PGF (0.01, 0.1, 1 μM), IFNG (0.05, 0.5, 5 nM) and TNF (0.05, 0.5, 0.5 nM) alone or in combination for 24 h. PGF and IFNG significantly increased the expression of MMP-1 mRNA. In addition, 1 μM PGF in combination with 5 nM IFNG stimulated MMP-1 and MMP-9 mRNA expression significantly more than either treatment alone. In contrast, IFNG significantly decreased the level of MMP-14 mRNA. The mRNA expression of TIMP-1, which preferentially inhibits MMP-1, was suppressed by 5 nM INFG. One μM PGF and 5 nM IFNG suppressed TIMP-2 mRNA expression. These results suggest a new role of MMPs: luteal MMPs stimulated by PGF and IFNG break down the extracellular matrix surrounding luteal cells, which accelerates detachment from the CL during luteolysis, providing an essential prerequisite for outflow of luteal cells from the CL to lymphatic vessels.     

Mobiloization of intracellular calcium ions in chicken and rat lymphocytes induced by T cell mitogens

Cytosolic Ca²⁺ is known to be an important factor in intracellular signaling pathways that regulate several cellular functions. The present study was designed to measure the intracellular concentrations of Ca²⁺ ([Ca²⁺]_i) in T cell mitogen-stimulated chicken lymphocytes, and to compare the results with those in rat lymphocytes. [Ca²⁺]_i was increased in the thymocytes, splenocytes and bursacytes of chickens, and in the thymocytes and splenocytes of rats following exposure to the mitogens phytohaemagglutinin (PHA) and concanavalin A (ConA). Increases were greatest in the thymocytes followed by the splenocytes and bursacytes. The PHA-induced changes in the thymocytes and splenocytes were similar in chickens and rats, but the ConA-induced increases were significantly lower in the chickens than rats. Pretreatment with EGTA before the application of PHA and ConA completely suppressed the rise in [Ca²⁺]_i in all the chicken lymphocytes, indicating that the increases that occurred in PHA- and ConA-treated chicken lymphocytes could be entirely attributed to the influx of extracellular Ca²⁺. On the other hand, the PHA- and ConA-induced increase in [Ca²⁺]_i in rat lymphocytes was not completely suppressed by EGTA, indicating the recruitment of Ca²⁺ from the intracellular Ca²⁺ pool. The results suggest species differences in the Ca²⁺-based responses to T cell mitogens between chicken lymphocytes and rat lymphocytes.     

Short-term transportation in a small vehicle affects the physiological state and subsequent water consumption in goats

We investigated the physiological effects on goats of transportation for one hour in a small truck. We also investigated food and water consumption after transportation. Eight adult goats (four castrated males and four ovariectomized females) were used. Plasma levels of cortisol, glucose and free fatty acids increased significantly within 15 min of the start of transportation, and these higher levels were maintained throughout transportation. These results indicate that transportation in a small truck activates the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system in goats. Despite activation of the sympathetic nervous system, heart rate (HR) in subjected animals during transportation did not differ from during the control animals, which were housed in their usual pen. However, after the transportation had ended and the goats started to eat fodder, HR increased significantly. There was no difference in the amount of food consumption between the control and transported goats. Water consumption in the first three hours after transportation was significantly lower in the transported goats than in the controls for the equivalent period. In the subsequent three hours, however, the transported goats consumed more water than the controls. Consequently, the total water consumption of the transported goats did not differ from that of the controls during the six hours after transportation. In conclusion, short-term transportation with a small vehicle activated the HPA axis and the sympathetic nervous system in goats. HR was not increased during transportation, but after the transportation had ended HR in transported goats was higher than that in control goats. After transportation, goats had consumed the same amount of food as control goats, but water consumption during three hours after the transportation was lower than that of control goats.     

Molecular dynamics of heterochromatin protein 1beta, HP1beta, during mouse preimplantation development

To elucidate the molecular dynamics of HP1beta in mouse preimplantation embryos, we examined the localization, dynamics, and mobility of HP1beta in the (pro)nucleus by live cell imaging. Time-lapse observation revealed that the chromatin association of HP1beta is regulated in a cell cycle-dependent manner. HP1beta was localized in the interphase nucleus and was dynamically dissociated from the nucleus during the metaphase stage. The HP1beta assembly and clustered heterochromatin structure were both found in the nuclei of 2-cell and later-stage embryos. Moreover, fluorescent recovery after photobleaching analysis implied that HP1beta is more freely mobile in the pronucleus of the 1-cell embryo than in the 4-cell nucleus. These results suggest that the chromatin configuration may be regulated by the stability and mobility of chromatin-associated proteins including HP1beta during early embryonic stages.     

Estimation of the carcass composition from a cross-section of the rib-loin from crossbred Japanese Black × Limousin F2 cattle by computer image analysis

The carcass composition of crossbred Japanese Black × Limousin F2 cattle was examined in order to find an accurate carcass composition equation. The test animals included 17 steers and 17 heifers. The 28 image measurements from the area encircling the vertical line to the thoracic vertebra and the line from the thoracic vertebra between the sixth and seventh rib‐bones were measured by computer image analysis. The relationships between the 29 parameters that added the carcass left side weight of the animal and the carcass composition were suggested. The carcass composition included muscle weight, muscle ratio, fat weight and fat ratio. The carcass composition from steers was estimated by an equation composed of these three or four parameters (R² = 90.80%, 79.30%, 90.75% and 73.70%, respectively). The selected parameters were measured without cutting the thoracic vertebra. The carcass composition from heifers was estimated by an equation composed of two to four parameters (R² = 96.15%, 90.98%, 93.60% and 88.22%, respectively). The parameters for the estimation of the muscle and fat weight, and muscle and fat ratio are very similar. Furthermore, the equations using the parameters could estimate the carcass composition from the Japanese Black × Limousin cattle resource population.     

Differences between carcass grades in some morphological, behavioral and physiological measurements at early and middle stages of fattening in crossbred steers

The differential variables for carcass grades were identified from morphological, behavioral and physiological measurements of young steers at a commercial farm. Thirty‐five Japanese Black × Holstein steers aged 6–10 months were randomly assigned to three pens. The steers had free access to ryegrass hay and a restricted amount of concentrate diet for the first 6 months of trial. They were then given oat straw ad libitum and an additional concentrate diet until slaughter. Behavioral observations (15 categories) were carried out once every 2 weeks for 2 h after feeding. Bodyweight was measured, blood sampled (for seven metabolic hormones and five metabolites), ultrasonic scanning conducted and physical measurements taken (10 parts for each animal) in months 1, 3 and 5 (early fattening stage, EFS) and in months 7, 9 and 11 (middle fattening stage, MFS) of the trial. Temperament scores during these procedures, entry order into restraint stalls, social rank and average daily gain were also assessed. A factor analysis and one‐way anova were used to identify clusters of variables which had different factor scores between carcass grades. As for the carcass yields, a cluster of chest girth and depth, bodyweight, withers and hip height, and rump length (P < 0.01), and a cluster of the frequency of scratching the body with facilities (P < 0.05) were identified as differential variables in the EFS. In the MFS, a cluster of concentrations of cortisol and epinephrine, and the frequency of eating straw were identified (P < 0.10). As for the carcass quality grade, a cluster of social rank, triglyceride concentration and the frequencies of stand‐chewing cud and eating hay, and a cluster of the frequency of investigating facilities (both P < 0.10) were identified in the EFS. In the MFS, a cluster of hip height, bodyweight, cannon circumference, chest depth, withers height and chest girth, and a cluster of the frequencies of eating a concentrate diet and stand‐chewing the cud, and social rank (both P < 0.10) were identified. In conclusion, bodyweight, chest girth and depth, withers and hip height were identified as good differential variables for future carcass grades of young steers. Facility enrichment that encourages steers to eat hay in the EFS, and to eat a concentrate diet in and after the MFS would be effective in upgrading carcass grades. High incidence of investigating and scratching the body with facilities and stand‐chewing the cud might lead to lower carcass grades.     

Myofibrillar proteolysis in chick muscle cell cultures during heat stress

The effect of heat stress on protein oxidation and myofibrillar proteolysis in chick myotubes was investigated. Myotubes were incubated at 37 or 41°C for 6 and 24 h. Protein carbonyl content, as an index of protein oxidation, increased more at 41°C than at 37°C for 6 and 24 h incubations. N^τ‐methylhistidine release as an index of myofibrillar proteolysis also increased more at 41°C than at 37°C for 6 and 24 h incubations. Proteasome activity also increased more under those same conditions. Calpain and cathepsin D but not B + L activities showed a greater increase at 41°C than at 37°C for 24 but not the 6 h incubation. These results indicate that heat stress increases protein oxidation and proteasome activity, resulting in an increase in myofibrillar proteolysis for short‐term incubation and, for long‐term incubation, it increases calpain, proteasome and cathepsin D activities, finally accelerating myofibrillar proteolysis in chick myotubes.     

Practical capability of a DNA pool‐based genome‐wide association study using BovineSNP50 array in a cattle population

Genome‐wide association mapping for complex traits in cattle populations is a powerful, but expensive, selection tool. The DNA pooling technique can potentially reduce the cost of genome‐wide association studies. However, in DNA pooling design, the additional variance generated by pooling‐specific errors must be taken into account. Therefore, this study aimed to investigate factors such as: (i) the accuracy of allele frequency estimation; (ii) the magnitude of errors in pooling construction and in the array; and (iii) the effect of the number of replicate arrays on P‐values estimated by a genome‐wide association study. Results showed that the Illumina correction method is the most effective method to correct the allele frequency estimation; pooling errors, especially array variance, should be taken into account in DNA pooling design; and the risk of a type I error can be reduced by using at least two replicate arrays. These results indicate the practical capability and cost‐effectiveness of pool‐based genome‐wide association studies using the BovineSNP50 array in a cattle population.     

尼日利亚热带雨林地区的内陆山谷中土壤发育和肥力特征: 矿物成分和粒度分布

The particle-size distribution and mineralogical composition of the clay (< 2 μm) and fine-sand (0.25--0.10 mm) fractions in soils of two inland valleys in Abakaliki and Bende, Southeast Nigeria, were investigated to provide basic information on soil-forming processes and agricultural potentials. These soils were silty or clayey, deriving from Cretaceous or Tertiary shale materials. The particle-size distribution and its computation on a clay-free basis revealed relatively remarkable lithologic breaks in a couple of pedons. The effect of lithologic discontinuities on soil mineralogical composition was not, however, conspicuous. Petrographic investigation revealed that quartz predominantly comprised the fine-sand fraction in the soils at both study sites. Nevertheless, the clay mineralogical composition of the soils was a mixture of kaolinite, irregularly interstratified smectite-illite intergrades (S/I), hydroxyl-Al interlayered 2:1 type clays (HICs), vermiculite, smectite, halloysite and illite along with fine-sized quartz in Abakaliki. The soils of Bende predominantly contained smectite, which was partially interlayered with hydroxyl-Al and kaolinite. It is suggested that seasonal floodwater has slowed the disintegration of weatherable clay minerals inherited from the shale, while quartz originating from the sandstone is predominant in the fine-sand fraction. Additionally, a possible soil-forming process observed at the both study sites was ferrolysis, which was indicated by a clear decreasing pattern of HICs downward in the soil profiles. The entry of S/I and vertical distribution patterns for a couple of clay minerals in the pedon suggested that the soils in Abakaliki have developed under the significant influence of aeolian dust delivered by the harmattan. The findings might describe a site-specific deposition pattern of harmattan dusts as well as hydromorphic soil-forming processes in the wetlands of the inland valleys.