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Megumi Kuroiwa Keisuke Koba Kazuo Isobe Ryunosuke Tateno Asami Nakanishi Yoshiyuki Inagaki Hiroto Toda Shigeto Otsuka Keishi Senoo Yuichi Suwa Muneoki Yoh Rieko Urakawa Hideaki Shibata 《Journal of Forest Research》2011,16(5):363-373
Measurements of gross NH 4 + and NO 3 ? production in forest soils were conducted using the 15N pool dilution method. Mineral topsoils (0?C10?cm depth) were collected from four forests from northern to southern Japan with a natural climate gradient to elucidate the mechanisms regulating gross nitrification rates in forest soils. Additionally, we attempted to evaluate the relative importance of heterotrophic nitrification in gross total nitrification using acetylene as a specific inhibitor of autotrophic nitrification. Distinct differences were found among sites in the gross rates of NH 4 + production (3.1?C11.4?mg?N?kg?1?day?1) and gross total nitrification (0.0?C6.1?mg?N?kg?1?day?1). The rates of gross heterotrophic nitrification were low in this study, indicating that heterotrophic nitrification is of minor importance in most forest mineral topsoils in Japan. Significant relations were found between gross autotrophic nitrification and gross NH 4 + production, soil N, and soil C concentrations, but none was found between gross autotrophic nitrification and soil pH. We determined the critical value of the gross NH 4 + production rates for gross autotrophic nitrification under which no gross autotrophic nitrification occurred, as well as the critical soil C/N ratio above which gross autotrophic nitrification ceased. Results show that tight coupling of production and consumption of NH 4 + prevents autotrophic nitrifiers from utilizing NH 4 + as long as NH 4 + availability is low. 相似文献
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Effect of nutrient levels during the far‐off period on postpartum productivity in dairy cows 
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下载免费PDF全文 Haruhi Hirabayashi Kenji Kawashima Tomoko Okimura Ayane Tateno Akitsu Suzuki Sadaki Asakuma Naoki Isobe Taketo Obitsu Toshihisa Sugino Shiro Kushibiki 《Animal Science Journal》2017,88(8):1162-1170
The present study aimed to determine the effects of differing nutrient levels during the far‐off period on postpartum metabolism and milk production in lactating cows. Twenty‐six multiparous cows were assigned to three dietary treatments in the far‐off period: a low‐energy diet (L, n = 9, 80% intake of the total digestible nutrients requirement), a moderate‐energy diet (M, n = 8, 105%) and a high‐energy diet (H, n = 9, 130%). During the close‐up period, all cows were provided with 105% intake. After parturition, all cows were fed a lactation diet. The BCS recovery was slow, and low milk yield was found in the H group. In the L group, BCS recovery was favorable after parturition, and lactation persistence was increased. The L group had low rumen endotoxin activity and a high initial ovulation rate after parturition. These findings indicate that a high‐energy diet during the far‐off period has a deleterious effect on milk production. In contrast, the restricted diet in the far‐off period increased adaptability with respect to peri‐parturition metabolic changes, improved the post‐parturition nutritional state, and increased milk production. Furthermore, it suggests that the nutrient levels in the far‐off period affect rumen endotoxin activity and reproductive function after parturition. 相似文献
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To confirm that freeze-thaw embolism is a primary stress for evergreen woody species in winter, hydraulic conductivity, photosynthesis and leaf water potential were measured during fall and winter in trees growing in a cool temperate zone (Nikko) and in a warm temperate zone (Tokyo). We examined two evergreen conifers that naturally occur in the cool temperate zone (Abies firma Siebold & Zucc. and Abies homolepis Siebold & Zucc.), and four evergreen broad-leaved woody species that are restricted to the warm temperate zone (Camellia japonica L., Cinnamomum camphora (L.) J. Presl, Ilex crenata Thunb. and Quercus myrsinaefolia Blume). In Tokyo, where no freeze-thaw cycles of xylem sap occurred, hydraulic conductivity, photosynthesis and water balance remained constant during the experimental period. In Nikko, where there were 38 daily freeze-thaw cycles by February, neither of the tracheid-bearing evergreen conifers showed xylem embolism or leaf water deficits. Similarly, the broad-leaved evergreen trees with small-diameter vessels did not exhibit severe embolism or water deficits and maintained CO(2) assimilation even in January. In contrast, the two broad-leaved evergreen trees with large-diameter vessels showed significantly reduced hydraulic conductivity and shoot die-back in winter. We conclude that freeze-thaw embolism restricts evergreen woody species with large-diameter vessels to the warm temperate zone, whereas other stresses limit the distribution of broad-leaved trees, that have small-diameter vessels, but which are restricted to the warm temperate zone. 相似文献
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Helal IE Misumi K Tateno O Kodama T Ishimaru M Yamamoto J Miyakoshi D Fujiki M 《American journal of veterinary research》2007,68(2):134-140
OBJECTIVE: To evaluate changes in serum cartilage oligomeric matrix protein (COMP) concentrations in response to exercise in horses. ANIMALS: 15 horses in experiment 1 and 27 horses in experiment 2. PROCEDURES: In experiment 1, 15 Thoroughbreds free of orthopedic disease underwent a standardized exercise protocol. Running velocity and heart rate (HR) were recorded, and blood samples were collected immediately before (baseline) and 1, 5, and 24 hours after a single episode of exercise. In experiment 2, 27 horses underwent 9 stages of a training program in which each stage consisted of 4 to 8 consecutive daily workouts followed by a rest day. Blood samples were collected immediately before the first and final daily workouts in each stage. Serum COMP concentrations were measured via inhibition ELISA with a monoclonal antibody (14G4) against equine COMP. RESULTS: In experiment 1, mean serum COMP concentration was significantly higher than baseline 1 and 5 hours after exercise and returned to baseline concentrations 24 hours after exercise. Mean serum baseline COMP concentration increased as the velocity of running at maximum HR and at an HR of 200 beats/min increased, being significantly higher during the third and fourth exercise tests than during the first. In experiment 2, mean baseline COMP concentration at the final workout of each stage was significantly higher than that at the first workout, beginning with stage 3. CONCLUSIONS AND CLINICAL RELEVANCE: Serum COMP concentrations changed significantly in response to exercise. Exercise may enhance movement of COMP into the circulation as well as change the basal turnover rate of COMP. 相似文献
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Biologic features of HIV-1 that correlate with virulence in the host 总被引：120，自引：0，他引：120
Individuals infected with the human immunodeficiency virus type 1 (HIV-1) may be asymptomatic or have AIDS-related complex or the acquired immuno deficiency syndrome (AIDS). Little is known about the factors that influence progression of infection to AIDS. In this study of isolates of HIV-1 obtained at intervals during the infection of four individuals, the development of disease was found to be correlated with the emergence of HIV-1 variants that were more cytopathic in vitro as the disease progressed and that replicated more efficiently in a wide variety of different human cells. The biologic properties of HIV-1 in vitro thus appear to reflect its virulence in the host. Further studies of such sequentially isolated viruses may lead to the identification of viral genes that govern pathogenesis. 相似文献
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Hideaki Shibata Rieko Urakawa Hiroto Toda Yoshiyuki Inagaki Ryunosuke Tateno Keisuke Koba Asami Nakanishi Karibu Fukuzawa Ayaka Yamasaki 《Journal of Forest Research》2011,16(5):374-385
Net nitrogen transformation was investigated under different climate conditions by soil transplantation and in situ incubation
of forest surface soils using the resin-core method. Selected conditions were considered to reflect those of the natural climate
gradient in the Japanese archipelago. Study sites were established in natural forests in northern Hokkaido (Uryu), northern
Kanto (Kusaki), central Kinki (Kamigamo), and southern Kyushu (Takakuma), representing the northernmost to the southernmost
island regions of Japan. Field experiments comparing soils incubated at “native” and “transplanted” sites were conducted from
June 2008 to May 2009. Net production, accumulation, and leaching of soil ammonium (NH4
+) and nitrate (NO3
−) were measured at each of the sites during the growing season (June–October), the dormant season (November–May), and throughout
the year. Net nitrate production was highest in Kusaki soil, especially during the growing season, whereas net ammonium production
was highest in Uryu soil, the coldest site, especially during the dormant season. Net nitrate production increased significantly
in soils transplanted to a warmer climate during the growing season. However, net ammonium production increased in soils transplanted
to colder climates during the dormant season. These findings indicate that, with the exception of the infertile soil samples
from Kamigamo, the range of natural climates in Japan has a significant effect on nitrogen availability in surface soil. In
addition, the original characteristics of the nitrogen cycle of the surface soil from each native site were retained, even
when marked changes in soil temperature (approximately 8°C) occurred after transplantation. 相似文献
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We examined soil N dynamics, including inorganic N concentration, net N transformation rates, and estimated plant N uptake
(EPNU) from soil N budgets, and litterfall inputs, in five Japanese cedar plantation stands of different ages (5, 16, 31,
42, and 89 years) in the Mt Gomadan Experimental Forest (GEF). Net soil N mineralization and nitrification rates did not differ
significantly between the youngest and oldest stands; soil moisture and inorganic N concentration were higher in the youngest
stand. The EPNU was highest in the 16-year-old stand and lowest in the 31-year-old stand, and had a significant negative correlation
with litter C:N ratio. The oldest (89-year-old) stand had a higher soil C:N ratio, lower proportion of nitrification rate
to mineralization rate (%NIT), and higher estimated plant NH4
+ uptake than did the other stands, indicating that changes of soil organic matter quality can alter soil N dynamics. These
results suggest that as a Japanese cedar plantation develops, soil N dynamics can be altered by the quantity and quality of
input litter and soil organic matter, and can generate the imbalance between N supply from soil and N demand by plant. 相似文献
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In Drosophila, the Jun amino-terminal kinase (JNK) homolog Basket (Bsk) is required for epidermal closure. Mutants for Src42A, a Drosophila c-src protooncogene homolog, are described. Src42A functions in epidermal closure during both embryogenesis and metamorphosis. The severity of the epidermal closure defect in the Src42A mutant depended on the amount of Bsk activity, and the amount of Bsk activity depended on the amount of Src42A. Thus, activation of the Bsk pathway is required downstream of Src42A in epidermal closure. This work confirms mammalian studies that demonstrated a physiological link between Src and JNK. 相似文献