Changes in Serum Steroid Hormones and Vitellogenin Levels in Cultured Female European Eels Anguilla anguilla during Artificially Induced Ovarian Development

Changes in serum concentrations of estradiol-17β, testosterone, 17α,20βdihydroxy-4-pregnen-3-one, and vitellogenin were investigated during ovarian development induced by injection of a salmon pituitary extract in cultured European eel Anguilla anguilla . Vitellogenesis was induced with a weekly dose of 50 mg pituitary extract/kg body weight. In eels receiving that dose, gonadsomatic indices ranged from 20–43% after the 10th–11th weekly injection. Body weights were relatively stable during vitellogenesis, but increased dramatically during final maturation. Serum estradiol-17β levels increased slightly during vitellogenesis and peaked at an average of 6.95 ng/mL at final maturation. The profile of serum vitellogenin followed that of estradiol-17β which increased markedly from an average of 0.36 to 20.72 mg/mL. Control levels of vitellogenin were undetectable throughout the study. Average serum levels of testosterone increased to a peak of 17.74 ng/mL in the early stage of vitellogenesis, followed by a sharp drop to initial levels (3.86 ng/mL) in the late stage of vitellogenesis, and then increased again to an average of 8.84 ng/mL at the final maturation stage. Serum 17α,20β-dihydroxy-4-pregnen-3-one was not detected (<50 pg/mL) throughout the experiment. Profiles of serum estradiol-17β, testosterone, and vitellogenin observed during ovarian development appear different from those found in salmonids and other teleosts. This study indicates, however, that cultured European eels are a useful model for study of gonadal maturation in the eel.     

Leaf-age effects on seasonal variability in photosynthetic parameters and its relationships with leaf mass per area and leaf nitrogen concentration within a Pinus densiflora crown

In the temperate zone of Japan, Pinus densiflora Sieb. et Zucc. bears needles of up to three age classes in the upper crown and up to five age classes in the lower crown. To elucidate the effects of leaf age on photosynthetic parameters and its relationships with leaf mass per unit area (LMA) and leaf nitrogen (N(l)) concentration on an area (N(a)) and mass (N(m)) basis, we measured seasonal variations in LMA, N(l), light-saturated photosynthetic rate (A(max)), stomatal conductance (g(s)), maximum rate of carboxylation (V(cmax)) and maximum rate of electron transport (J(max)) in leaves of all age classes in the upper and lower crown. Leaf mass per unit area increased by 27% with increasing leaf age in the lower crown, but LMA did not depend on age in the upper crown. Leaf age had a significant effect on N(m) but not on N(a) in both crown positions, indicating that decreases in N(m) resulted from dilution. Photosynthetic parameters decreased significantly with leaf age in the lower crown (39% for A(max) and 43% for V(cmax)), but the effect of leaf age was not as great in the upper crown, although these parameters exhibited seasonal variation in both crown positions. Regression analysis indicated a close relationship between LMA and N(a), regardless of age class or when each age class was pooled (r(2) = 0.57-0.86). Relationships between LMA and N(a) and among A(max), V(cmax) and J(max) were weak or not significant when all age classes were examined by regression analysis. However, compared with older leaves, relationships among LMA, N(a) and A(max) were stronger in younger leaves. These results indicate that changes in LMA and N(l) mainly reflect light acclimation during leaf development, but they are only slightly affected by irradiance in mature leaves. In conclusion, LMA and N(l) are useful parameters for estimating photosynthetic capacity, but age-related effects need to be taken into account, especially in evergreen conifers.     

Growth performance and carcass traits of pigs subjected to marginal dietary restrictions during the grower phase.

Sixty-four individually housed pigs were used to investigate the effect of amino acid content of finisher diets on growth performance of pigs subjected to marginal dietary amino acid restrictions (80% of the 1988 NRC lysine recommendation) during the grower phase. In each of the two trials, low- and high-amino-acid grower diets (.421 and .765 g lysine/MJ DE, respectively) and four finisher diets (.421, .516, .612, and .707 g lysine/MJ DE) were randomly assigned within sex to 16 gilts and 16 castrated males weighing 23.0 +/- 2.0 kg in a 2 x 4 factorial arrangement of treatments. The average weight of pigs after a completion of diet change was 50.4 +/- 2.1 kg. All pigs were slaughtered at an average weight of 105.2 +/- 4.1 kg. Ultrasound backfat thickness was measured at the time of diet change and before slaughter. Pigs were allowed ad libitum access to feed and water. During the grower phase, pigs fed the high-amino-acid diet grew faster (P < .001) and more efficiently (P < .001) and had less ultrasound backfat (P < .001) than those fed the low-amino-acid diet. The grower diet had no effect on weight gain during the finisher phase. Consequently, pigs fed the high-amino-acid grower diet had better overall weight gain (P < .01) than those fed the low-amino-acid diet. The rate of lean accretion was, however, similar between the two groups of pigs. Furthermore, pigs fed the low-amino-acid grower diet seemed to have better carcass quality, as indicated by less ultrasound backfat (P < .01) and larger carcass longissimus muscle area (P < .05). Average and 10th rib carcass backfat decreased linearly (P < or = .05) and lean accretion rate improved linearly (P < .05) as the amino acid content of finisher diets increased, but there was no grower x finisher diet interaction in these and other response criteria. Although no evidence of compensatory weight gain was observed, it is possible that compensatory lean tissue growth may have occurred in pigs subjected to early amino acid restrictions at the expense of fatty tissue growth.     

Development of the hypophysis of the arctic lamprey,Lampetra japonica

The hypophysis of early larval stages, from the moment of hatching on the 18th day after fertilization to the 101st day of larval life, of the arctic lamprey Lampetra japonica was studied with scanning and transmission electron microscopes. A solid cord of cells of the distal part of the nasopharyngeal duct represents the early adenohypophysis. On the 20th day after fertilization, several of the epithelial cells of this structure showed first indications of secretory activity with an extensive Golgi apparatus and small electron-dense secretory granules. On the 26th day, non-secretory, stellate (=supporting) cells and secretary cells can be distinguished. Already on the 39th day, two different parts can be distinguished in the adenohypophysis: the pars distalis with cells containing small dense granules, and the pars intermedia with cells containing larger granules of medium density. The number of granulated cells increases steadily; on the 101st day two pars distalis cell types can be distinguished. The neurohypophysis consists of a thin anterior and a thick posterior part. Already on the 20th day single nerve terminals in the ependymal layer of the diencephalic (=infundibular) floor contain dense elementary granules. The number of granule-containing terminals increases steadily; on the 101st day almost all terminals contain granules. The present observations suggest an early secretory function of the lamprey hypophysis.     

Relationship between trace elements status in mane hair and atrial fibrillation in horse

To investigate the relationships between trace elements concentrations in hair and atrial fibrillation (AF) in horses, concentrations of nineteen trace elements were detected in hair using the particle induced X-ray emission (PIXE) method. The horses were assigned to either control (n=22, no abnormalities) or AF groups (n=5) based on electrocardiograph findings. The mean concentrations of Ca and Zn in the hair of the AF group were significantly higher than those in the control group. The Zn/Cu ratio of the hair in the AF group (29.8 +/- 5.5) was significantly higher than that in the control group (23.4 +/- 2.2, P<0.05). The results of the present study suggest that there is a relationship between elevated concentrations of Ca and Zn in hair and AF.     

Global Model Simulations of the Transport of Asian and Sahara Dust: Total Deposition of Dust Mass in Japan

We simulated the global transport of dust emitted from all major dust source regions on earth by using a global three-dimensional chemical transport model for the year 2000. A modified dust emission flux scheme and an advanced nonlocal diffusion scheme for accurately determining the atmospheric eddy diffusivity in the atmospheric boundary layer were implemented to improve the chemical transport model. We specifically examined and analyzed dust storms that occurred in China and northern Africa. Four scenarios representing the global transport of dust from dust storms originating in the Loess region and the Gobi, Takla Makan, and Sahara deserts, respectively, were simulated. The results of each scenario were then compared with those resulting from all major dust source regions on earth, to identify which deserts have a major impact on dust transport and its deposition in Japan. The dust from the Sahara desert, most from the western part that was found in this study, reached Japan in 9–10 days, while Gobi and Loess region dust took 2 to 3 days, and 4 days for Takla Makan dust. The model-calculated monthly total deposition of dust mass from all major dust source regions was compared with comprehensive measurements of total deposition collected at sampling stations distributed over Japan, and good agreement was generally found. From these analyses, it was also indicated that dust emitted from other deserts, including the Turkestan, Iranian, and Arabian, could have a significant impact on dust deposition on Japan.     

Visfatin: a protein secreted by visceral fat that mimics the effects of insulin

Fat tissue produces a variety of secreted proteins (adipocytokines) with important roles in metabolism. We isolated a newly identified adipocytokine, visfatin, that is highly enriched in the visceral fat of both humans and mice and whose expression level in plasma increases during the development of obesity. Visfatin corresponds to a protein identified previously as pre-B cell colony-enhancing factor (PBEF), a 52-kilodalton cytokine expressed in lymphocytes. Visfatin exerted insulin-mimetic effects in cultured cells and lowered plasma glucose levels in mice. Mice heterozygous for a targeted mutation in the visfatin gene had modestly higher levels of plasma glucose relative to wild-type littermates. Surprisingly, visfatin binds to and activates the insulin receptor. Further study of visfatin's physiological role may lead to new insights into glucose homeostasis and/or new therapies for metabolic disorders such as diabetes.     

Horizontal and vertical variations in photosynthetic capacity in a Pinus densiflora crown in relation to leaf nitrogen allocation and acclimation to irradiance

We measured horizontal and vertical gradients of light (rPPFD) along four first-order branches of a Pinus densiflora Sieb. & Zucc. crown, and compared variations in specific leaf area (SLA), needle nitrogen concentration (N), chlorophyll concentration (Chl) and photosynthetic capacity (i.e., maximum rate of carboxylation (V(cmax))) along the two axes. The horizontal gradient of rPPFD along first-order branches was similar in magnitude to the vertical gradient of rPPFD from the upper to the lower crown. None of the measured parameters (i.e., SLA, N, Chl and Vcmax) were strictly proportional to rPPFD, although they were more or less correlated with light when data obtained for all of the crown were pooled (r(2) = 0.31-0.80). The slope of rPPFD against N on an area basis (Narea) for a branch in the middle of the crown orientated northward was significantly greater than the slope for a similar branch orientated southward. Horizontal variations were unrelated to age effects because measurements were all on 1-year-old needles. We conclude that factors other than light (i.e., orientation) may influence N allocation within branches. There was considerably less variation in the relationship of Vcmax to Narea (r2 = 0.58) than in the relationship of Vcmax to rPPFD (r2 = 0.41). Fractional N distribution among components of the photosynthetic machinery was constant within the crown. Together with the relationships between rPPFD and N on a mass basis (r2 = 0.80) and SLA and Vcmax (r2 = 0.60), these findings suggest that most light acclimation in P. densiflora occurs through changes in needle morphology (e.g., SLA) during development.