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1.
Yuichi Kano Yôichi Kawaguchi Tomomi Yamashita Tsuneo Sekijima Yukihiro Shimatani Yoshinori Taniguchi 《Landscape and Ecological Engineering》2013,9(2):281-287
We validated the effects of a passive integrated transponder (PIT) tagging process on the oriental weather loach Misgurnus anguillicaudatus. Laboratory experiments were conducted to assess the effects of PIT tagging on fish survival, growth, wound healing, and tag omission. Two tagging protocols, standard syringe injection versus insertion through a small hole pierced by a fine needle-shaped awl, were compared using a 12.5 × 2.07 mm2 tag. A control group was also included. In comparison with the awl technique, syringe injection heightened the mortality of the loach and delayed healing of the wound caused by tag insertion. No effects of either PIT tagging method were detected on the growth of surviving loach. We also field-tested similarly tagged populations within a river-based irrigation system of Sado Island, Japan. Two different sized tags (long, 12.5 × 2.07 mm2; short, 8.5 × 2.12 mm2) were compared by using antenna loggers which detected fish movement through gates and automatically logged tagged fish’s tag IDs and timestamps. By comparing logged data and actual fish collection surveys both below and above the gates, 77% and 30% of actual loach movements were confirmed to have been successfully logged for the long and short tags, respectively. The awl insertion technique with the longer tag is therefore recommended for use in similar studies of smaller fish species. 相似文献
2.
Shimatani A Kaneko J Tomita T Kamio Y 《Bioscience, biotechnology, and biochemistry》1999,63(10):1828-1830
A 2-residue (D12I13) segment of LukS of a staphylococcal leukocidin component is an essential region for the hemolytic function of LukS towards rabbit erythrocytes in the presence of LukF. Here, we report that insertion of D, I, or AA residue(s) between A11 and E12 residues of LukS-PV, in which the 2-residue D12I13 segment in LukS was absent, confers the full LukS function on LukS-PV, which has only 4% hemolytic activity of that of LukS towards rabbit erythrocytes. 相似文献
3.
Based on direct field measurement, this study quantitatively estimated the litter dynamics on the forest floor for a 1-year-period
and then investigated its influence on the seedling dynamics of Castanopsis sieboldii, as well as interactions with adults in a subtropical forest in southern Japan. Litter dynamics is composed of three major
components: falling litter, transport, and decomposition on the forest floor. Litterfall was measured by litter traps and
did not exhibit clear spatial tendency. Lateral input was assessed by newly accumulated litter beneath the traps and showed
no spatial variation, either. In contrast, lateral output of litter, which was quantified from disappearance of artificial
litter, was correlated with local topography. Consequently, we found considerable spatial variations and seasonal changes
in litter dynamics on the forest floor. In addition, we constructed survival models of C. sieboldii seedlings at the individual level. The lateral movement of accumulated litter had an influence on the survival of seedlings,
which mostly occurred in periods of typhoons with heavy rain. Meanwhile, the distance from canopy trees, which is assumed
to be a spacing mechanism due to seedling/adult interactions, played a lesser role in this subtropical forest. Our results
suggest that the stability of accumulated litter on the forest floor was a predominant factor in the spatial dynamics of the
early life stage of C. sieboldii. 相似文献
4.
Shimatani T Inoue M Iwamoto K Hyogo H Yokozaki M Saeki T Tazuma S Horikawa Y Harada N 《Helicobacter》2005,10(3):256-265
BACKGROUND: Follicular gastritis is thought to be caused by Helicobacter pylori infection. However, the pathophysiology of it remains unclear. MATERIALS AND METHODS: We assessed gastric acidity in 15 patients with follicular gastritis, aged 20-37 years, using a 24-hour intragastric pH-metry, as well as by histologic and serologic evaluations; and compared it with that in other age-matched groups: 18 cases of H. pylori-positive antrum-predominant gastritis, 12 of pangastritis, and 24 H. pylori-negative normals. In eight cases with follicular gastritis, it was re-assessed 6 months after the eradication therapy for H. pylori. RESULTS: During nighttime, the percentage of time with intragastric pH above 3.0 in follicular gastritis was significantly higher than that in normals (p<.0001), and in antrum-predominant gastritis (p<.001), but was comparable with that in pangastritis. In the daytime period, this parameter in follicular gastritis was significantly higher than that in normal (p<.001), in antrum-predominant gastritis (p<.001), and in pangastritis (p<.05). Marked mononuclear cell and neutrophil infiltration but no apparent glandular atrophy were observed in both the antrum and corpus. Serum pepsinogen I/II ratio was significantly lower in follicular gastritis than that in normals (p<.0001) and in antrum-predominant gastritis (p<.001), whereas serum gastrin was significantly higher than that in normals (p<.0001), in antrum-predominant gastritis (p<.01) and in pangastritis (p<.05). After eradication for H. pylori, all of the parameters in follicular gastritis were altered to the same ranges as those in normals. CONCLUSIONS: In follicular gastritis, gastric acidity is significantly reduced, but can be normalized by eradication of H. pylori. It can thus be speculated that inflammatory cytokines or H. pylori-infection-induced prostaglandins might strongly inhibit gastric acid secretion in follicular gastritis. 相似文献
5.
Transcriptomic analysis indicates putative metabolic changes caused by manipulation of phosphorus availability in rice leaves 总被引:10,自引:0,他引:10
6.
Hironori Hayashi Yukihiro Shimatani Kotaro Shigematsu Jun Nishihiro Shinya Ikematsu Y?ichi Kawaguchi 《Landscape and Ecological Engineering》2012,8(2):129-143
Riverine floodplains play many important roles in river ecosystems. However, many floodplains have suffered degradation or loss of ecological function due to excessive river improvements or through changes in agricultural systems. As a result, many floodplain restoration projects are being conducted worldwide. One of the many methods being implemented to restore floodplain vegetation is flood water seed dispersal. In this technique, precisely estimating the effect of seed dispersal by flood water is important in order to achieve successful floodplain revegetation. Here, we focus our attention on sediment transport by flood water into the Azamenose Swamp, a restored floodplain. We attempt to estimate the function of seed deposition in the restored floodplain and explain how the seeds are deposited in the floodplain by flood water. The result suggests that the restored floodplain functions as a more appropriate deposition site for seeds than the riverbanks of the main river. It was also found that the distance from the inflow site and the weight of the sediment were related to seed deposition. 相似文献
7.
When we calculate mortality along a gradient such as size, dividing into size classes and calculating rates for every class
often involves a trade-off: fine class intervals produce fluctuating rates along the gradient, whereas broad ones may miss
some trends within an interval. The same trade-off occurs when we want to illustrate size distribution by a histogram. This
paper introduces nonparametric methods, published in a statistical journal, into forest ecology, in which the fine-class strategy
is used in an extreme way: (1) a smoothly changing pattern is approximated by a fine step function, (2) the goodness-of-fit
to the data and the smoothness along the gradient are formulated as a weighting sum within a Bayesian framework, (3) the Akaike
Bayesian Information Criterion (ABIC) selects the weighting system that most appropriately balances the two demands, and (4)
the values of the step function are optimized by the maximum likelihood method. The nonparametric estimates enable us to represent
various patterns visually and, unlike parametric modeling, calculations do not demand the determination of a functional form.
Mortality and size distribution analyses were conducted on 12-year forest tree monitoring data from a 4 ha permanent plot
in an old-growth warm–temperate evergreen broad-leaved forest in Japan. From trees of 11 evergreen species with a diameter
at breast height (DBH) greater than 5 cm, we found three types of trend with increasing DBH: decreasing, ladle-shaped and
constant mortality. These patterns reflect variations in life history particular to each species. 相似文献
8.
The patch mosaic of an old-growth warm-temperate forest: patch-level descriptions of 40-year gap-forming processes and community structures 总被引:1,自引:0,他引:1
Tohru Manabe Kenichiro Shimatani Satoko Kawarasaki Shin-Ichi Aikawa Shin-Ichi Yamamoto 《Ecological Research》2009,24(3):575-586
Old-growth forests consist of various types of small patches that reflect their own gap-forming process, which includes changes
in environmental conditions occurring over several decades. We reconstructed the gap-forming processes that had occurred during
a 40-year period for eight representative patches of an old-growth evergreen broad-leaved forest in Japan, and examined the
current community structure. The selected patches were based on (1) changes in canopy heights estimated from aerial photographs
taken in four different years, (2) long-term ecological research (LTER) monitoring records, and (3) a recent field survey,
so that they sufficiently covered characteristic gap-forming processes such as a new gap, an old gap and consistently closed
canopy. Height and diameter at breast height (DBH) were measured on all living trees taller than 1.3 m. In their height distributions,
currently almost closed patches that were open in 1966 show a rotated sigmoid, whereas their DBH distributions are an inverse
J-shape. In contrast, patches that have been consistently under a closed canopy exhibit gentle inverse J-shapes for both distributions.
For species composition, there are no clear contrasts associated with the past gap-forming processes except for the existence
of fast-growing deciduous species in large currently open patches. Our results suggested that the variation in several decades
of gap-forming processes played a central role in the high patch diversity and the complex patch mosaic of the forest. Diverse
gap-forming processes created micro-environmental heterogeneity both vertically and horizontally, and contributed to the maintenance
of the species-rich, warm-temperate old-growth forest. 相似文献
9.
10.
Pollen flow, seed dispersal and individual reproductive success can be simultaneously estimated from the genotypes of adults and offspring using stochastic models. Using four polymorphic microsatellite loci, gene flow of the wind-pollinated and wind-seed-dispersed dioecious tree species, Fraxinus mandshurica var. japonica, was quantified in a riparian forest, in northern Japan. In a 10.5-ha plot, 74 female adults, 76 male adults and 292 current-year seedlings were mapped and genotyped, together with 200 seeds. To estimate dispersal kernels of pollen and seeds, we applied normal, exponential power, Weibull, bivariate t-distribution kernels, and two-component models consisting of two normal distribution functions, one with a small and one with a large variance. A two-component pollen flow model with a small contribution (26.1%) from short-distance dispersal (sigma = 7.2 m), and the rest from long-distance flow (sigma = 209.9 m), was chosen for the best-fitting model. The average distance that integrated pollen flows inside and outside the study plot was estimated to be 196.8 m. Tree size and flowering intensity affected reproduction, and there appeared to be critical values that distinguished reproductively successful and unsuccessful adults. In contrast, the gene flow model that estimated both pollen and seed dispersal from established seedlings resulted in extensive seed dispersal, and the expected spatial genetic structures did not satisfactorily fit with the observations, even for the selected model. Our results advanced small-scale individual-based parentage analysis for quantifying fat-tailed gene flow in wind-mediated species, but also clarified its limitations and suggested future possibilities for gene flow studies. 相似文献