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51.
The brain nanopeptide arginine vasotocin (AVT) and its mammalian homolog arginine vasopressin are involved in the regulation of social and reproductive behavior. We investigated the relationship between social rank formation and the brain AVT system in the false clown anemonefish (Amphiprion ocellaris), which forms a social rank that leads to sex differentiation in higher-ranked individuals. Tanks of three sexually immature fish were kept for 90 days and each fish’s behavior was observed once a month. The social rank of each individual was distinguishable by behavior, but gonadosomatic index (GSI) did not differ significantly. The number of AVT neurons in the magnocellular layer in the preoptic area (POA) increased in subordinate individuals and declined with increasing hierarchical dominance. These results suggest that social rank formation modulates AVT production in the brain of the clown anemonefish and may influence their later sex differentiation.  相似文献   
52.
53.
A feasibility study was carried out to determine whether water-soluble salmon meat could be manufactured by conjugating a glycosyl unit using the Maillard reaction. Spawned out salmon meat was washed, mixed with alginate oligosaccharide (AO) and sorbitol, lyophilized, and then heated at 60°C and 5–95% relative humidity (RH) to introduce AO (the mean degree of polymerization was six) into the myofibrillar proteins through the Maillard reaction. The reaction progressed with an increase in the reaction humidity and the amount of AO bound to the protein reached >150 μg/mg at RH 65 and 90%. However, the protein glycosylation under high humidity impaired protein solubility and the meat protein became effectively water-soluble with the conjugation with AO at reaction conditions of 60°C and RH 35%. The improved characteristics of the meat protein were highly stable at room temperature. Further, the water-soluble protein can be prepared from the frozen salmon meat stored at −25°C for 60–90 days. These results indicate that protein glycosylation has strong potential for use with spawned out chum salmon. The suppression of protein denaturation during processing is important to obtain the high water-soluble meat protein.  相似文献   
54.
We examined open-grown Acer mono Maxim. trees of different sizes to test the hypotheses that (1) hydraulic limitation increases with tree size, thereby reducing photosynthesis, and (2) photosynthetic water- and nitrogen-use efficiencies change with tree size. Maximum net assimilation rate per unit dry mass was significantly lower in large trees than in small trees, whereas leaf nitrogen concentration increased with tree size. As a consequence, photosynthetic nitrogen-use efficiency decreased with increase in tree size. Photosynthetic water-use efficiency, however, increased with tree size, partly as a result of reduced stomatal conductance. Neither root-to-leaf hydraulic conductance nor minimum leaf water potential changed with tree size.  相似文献   
55.
Seasonal and substrate effects on first-year seedling establishment of major conifer species (Abies mariesii, Abies veitchii, Picea jezoensis var. hondoensis, and Tsuga diversifolia) were assessed in an old-growth subalpine forest in central Japan. Older seedlings (≥1 year) were more abundant on woody debris (WD), such as fallen logs, than on soil. It is known that this preferential seedling establishment on WD is determined by the first-year seedling establishment. The present results indicate that first-summer seedling survivorship clearly contributes to the creation of such seedling–substrate associations, because mortality during the first-summer was greater on soil than WD but that during the first-autumn/winter was not different. Although the standardized mortality rate of current-year seedlings on WD was not so different among the three seasons, that on soil significantly decreased in the winter; indicating that soil is not an unsuitable substrate for seedling survivorship during snow-covered winter. Thus, it can be concluded that biotic and abiotic factors enhancing seedling mortality on soil are most active during summer, and seedling–substrate associations seem to be determined mainly during the first-summer soon after seedling emergence. Furthermore, the first-year survivorship of P. jezoensis var. hondoensis, which has smaller-sized seeds/seedlings that are disadvantageous for early survival, decreased with progressing WD decay toward soil. This suggests that the properties of WD also affect current-year seedling survivorship, especially for species sensitive to substrate properties. In conclusion, initial survivorship affects seedling bank dynamics, and such early dynamics are greatly regulated by the highly heterogeneous substrate availability on forest floors.  相似文献   
56.
Highly condensed lignin can be transformed by three reactions — phenolation, hydroxymethylation, and neutral sulfonation — to water-soluble lignosulfonate. To elucidate reactivities and products in the latter two reactions, simple compounds were selected as lignin model compounds. With hydroxymethylation of creosol at 60°C, the yield of a condensed-type product with the diarylmethane structure was less than 10%. Hydroxymethylation of 1-guaiacyl-1-p-hydroxy-phenylethane (compound VI) as a phenolized guaiacyl lignin model compound gave four compounds. The initial reaction introduced the hydroxymethyl group mainly in the guaiacyl nucleus, and the additional reaction created two hydroxymethyl groups in the p-hydroxyphenyl nucleus. Contrary to our estimation, treatment of the models with 13C-labeled formaldehyde (H13CIIO) did not form any diarylmethane structure. Neutral sulfite treatment of hydroxymethylated products gave corresponding sulfonates in high yields. Phenolized guaiacylglycerol--aryl ether (compound XVI) showed a reactivity similar to that of compound VI.This paper was presented at the 45th and 46th annual meetings of the Japan Wood Research Society at Tokyo and Kumamoto, April 1995 and April 1996, respectively  相似文献   
57.
Grain shape is an important trait for improving rice yield. A number of quantitative trait loci (QTLs) for this trait have been identified by using primary F2 mapping populations and recombinant inbred lines, in which QTLs with a small effect are harder to detect than they would be in advanced generations. In this study, we developed two advanced mapping populations (chromosome segment substitution lines [CSSLs] and BC4F2 lines consisting of more than 2000 individuals) in the genetic backgrounds of two improved cultivars: a japonica cultivar (Koshihikari) with short, round grains, and an indica cultivar (IR64) with long, slender grains. We compared the ability of these materials to reveal QTLs for grain shape with that of an F2 population. Only 8 QTLs for grain length or grain width were detected in the F2 population, versus 47 in the CSSL population and 65 in the BC4F2 population. These results strongly suggest that advanced mapping populations can reveal QTLs for agronomic traits under complicated genetic control, and that DNA markers linked with the QTLs are useful for choosing superior allelic combinations to enhance grain shape in the Koshihikari and IR64 genetic backgrounds.  相似文献   
58.
Genetic improvement of resistance to infectious diseases is a challenging goal in animal breeding. Infection resistance involves multiple immunological characteristics, including natural and acquired immunity. In the present study, we developed an experimental model based on genetic selection, to improve immunological phenotypes. We selectively established three mouse lines based on phagocytic activity, antibody production and the combination of these two phenotypes. We analyzed the immunological characteristics of these lines using a lipopolysaccharide (LPS), which is one of the main components of Gram‐negative bacteria. An intense immunological reaction was induced in each of the three mouse lines. Severe loss of body weight and liver damage were observed, and a high level of cytokine messenger RNA was detected in the liver tissue. The mouse line established using a combination of the two selection standards showed unique characteristics relative to the mouse lines selected on the basis of a single phenotype. Our results indicate that genetic selection and breeding is effective, even for immunological phenotypes with a relatively low heritability. Thus, it may be possible to improve resistance to infectious diseases by means of genetic selection.  相似文献   
59.
Herbivore damage can induce the host plant to alter the chemical and physical qualities of its leaves, which is thought to be a plant strategy—termed “induced response”—for avoiding further herbivory. In woody plants, many studies have considered variation in induced response with resource availability, but few studies have examined this variation in relation to growth patterns of woody plants. We studied the phenotypic variability of induced response within successively flushing Quercus serrata seedlings. Q. serrata seedlings were grown under controlled conditions. The controlled factors were herbivore damage (herbivore-damaged and -undamaged) and soil fertility (low and high). At each flush stage, the concentrations of condensed tannin (CT), total phenolics (TP), and nitrogen (N) in leaves were analyzed, and the leaf mass per area (LMA) was measured. CT and TP concentrations in leaves and LMA were higher in herbivore-damaged seedlings. Leaves of the first flushes showed greater sensitivity to herbivore damage and had a higher CT concentration than leaves of the later flushes. Furthermore, seedlings growing in low-fertility soil showed a greater induced response. The results suggest that the induced response of Q. serrata seedlings was related to the contributions of the tissue to current productivity. Leaves of the first flush showed a greater induced response, possibly because they play an important role in subsequent growth. The potential of Q. serrata seedlings to adjust the properties of leaves depending on herbivory and soil fertility in relation to growth patterns may be advantageous on the forest floor, where seedlings grow in soil of heterogeneous fertility and are constantly exposed to herbivory.  相似文献   
60.
Two isolates of mecA-positive methicillin-resistant Staphylococcus aureus (MRSA) from retail raw chicken meat were characterized by phenotypic and genotypic methods. One isolate showed the human biovar, coagulase type III, phage group I * III, the lack of production of enterotoxins and TSST-1, and resistance to PCG/ABPC/EM/GM/KM. The other isolate showed the human biovar, coagulase type III, phage group III, production of enterotoxin C and TSST-1, and resistance to PCG/ABPC/CEZ. The biotyping results indicate that the two isolates showed characteristics of human S. aureus. They also harbored SCCmec type IV, which has prevalently been found in community-acquired MRSA isolates. This paper is the first publication regarding MRSA isolates from raw chicken meat in Japan.  相似文献   
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