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41.
Abstract: The cephalopod receptor of particle motion was identified. In a previous study, it was suggested that statocysts served this function, but there was no direct supporting evidence, and epidermal hair cells had not been conclusively ruled out. Experiments on Octopus ocellatus were conducted using respiratory activity as an indicator of sound perception. Intact animals clearly responded to 141-Hz particle motion at particle accelerations below 1.3 × 10−3 m/s2 , and the mean perception threshold at this frequency was approximately 6.0 × 10−4 m/s2 . Specimens in which the statoliths had been surgically removed did not show any response for accelerations up to 3.9 × 10−3 m/s2 at 141 Hz, which was approximately 16 dB greater than the mean perception threshold at this frequency. Specimens that had undergone a control operation in which the statoliths remained intact showed positive responses at 2.8 × 10−3 m/s2 for the same frequency stimulus. This indicates that the statocyst, which is morphologically similar to the inner ear system in fish, is responsible for the observed responses to particle motion in O. ocellatus . This is the first direct evidence that cephalopods detect kinetic sound components using statocysts. 相似文献
42.
We examined spatial and temporal variations in the species composition of two seagrass species, Zostera marina and Z. caespitosa, in a lagoon facing the Sea of Okhotsk. We also considered how those variations affected habitat quality for motile epifauna, especially for a commercial shrimp. A long-interval comparison between 1996 and 2013 showed that seagrass species composition in the lagoon did not vary, while their relative abundances did. A survey in 2012 revealed that the abundance of Z. caespitosa was affected by the abundance of Z. marina, water depth, and location in the lagoon. Although these seagrass species have similar aboveground morphology, differences in their fine structures were detected. Diversities of motile animals inhabiting the seagrass species were the same. Differences in seagrass utilization were observed when we focused on a commercial shrimp, Pandalus latirostris. This shrimp always preferred higher densities of shoots irrespective of the species and seasonally changed their preference for the number of leaves per shoot. They were therefore more abundant in Z. caespitosa, which had those structural characteristics. The results suggest that the management of shrimp resources could be improved by flexibly changing protected areas in accordance with the dynamics of seagrass distribution in the lagoon. 相似文献
43.
Vita Ratri CAHYANI Jun MURASE Eiji ISHIBASHI Susumu ASAKAWA Makoto KIMURA 《Soil Science and Plant Nutrition》2009,55(2):264-270
The present study compared the capsid gene ( g23 ) of T4-type bacteriophages (phages) in Mn nodules with those in the plow layer soil and subsoils of two Japanese paddy fields by applying the primers MZIA1bis and MZIA6 to DNA extracts from the nodules and soils. The deduced amino acid sequences of the g23 genes in the Mn nodules were similar to those in the plow layer soil and in the subsoils. This result indicated that similar T4-type phage communities developed at these sites and that the diversity of T4-type phage communities was wide enough to cover those in the plow layer soil and in the subsoils. The majority of g23 clones formed several clusters with the clones and phages obtained from far-apart paddy fields, and the sequences of two clones were completely identical to a phage and a clone from other paddy fields at the nucleotide or amino acid level, indicating horizontal transfer of g23 genes between those paddy fields. A clone with a long nucleotide residue (686 bp) and a distribution remote from the other clones in the phylogenetic tree indicated that there were many uncharacterized, novel g23 genes in the paddy fields. 相似文献
44.
Ikue Murata Sigefumi Saruki Katsuyoshi Kubota Sachiko Inoue Naoaki Tashiro Tsutomu Enoki Yasuhiro Utsumi Susumu Inoue 《Journal of Forest Research》2009,14(5):296-301
Effects of sika deer (Cervus nippon) and dwarf bamboo (“sasa;” Sasamorpha borealis) on seedling emergence and survival were investigated in cool-temperate mixed forests in the Kyushu mountain range, Japan.
We compared the effects of sika deer between two sites with different sika deer densities. One site (no-sasa forest) has sparse
cover of S. borealis and a high density of sika deer, and the other site (sasa forest) has dense cover of S. borealis with a low density of sika deer. In the no-sasa forest, more seedlings emerged and the survival rate of the seedlings was
higher compared with the sasa forest. Compared with the sasa forest, the canopy in the no-sasa forest was more open, the organic
layer was shallower and drier, the mean daily soil temperature was higher, and soil temperature fluctuated more widely. Those
environmental parameters did not differ between unfenced and fenced plots. The comparison between the sasa and no-sasa forests
suggested that removal of S. borealis by sika deer had an indirect positive effect on seedling emergence and survival. However, the fenced-plot experiments indicated
that sika deer inhibited seedling emergence and survival. These contradictory conclusions could result from the much larger
negative effects of S. borealis on seedling emergence and survival compared with the effects of sika deer browsing. 相似文献
45.
Masaru Fujinoki Tomoko Koito Suguru Nemoto Mitsugu Kitada Yoko Yamaguchi Susumu Hyodo Hideki Numanami Nobuyuki Miyazaki Koji Inoue 《Fisheries Science》2012,78(1):139-146
Various invertebrates inhabiting hydrothermal vents harbor thiotrophic endosymbionts that provide the host with nutrients
and are possibly involved in the detoxification of harmful sulfides. In this study, we first determined the partial 16S rRNA
gene sequence of the thiotrophic symbiont of the deep-sea mussel Bathymodiolus septemdierum, a dominant species at hydrothermal vents in the Izu–Ogasawara (Bonin) area. We then designed a new probe, Bsob692, for fluorescent in situ hybridization (FISH) using regions completely conserved among thiotrophic symbionts of all
bathymodiolin mussels and established the protocol for FISH to compare the distribution and amount of the symbiont using an
image analysis program that is commercially available. We compared fluorescent intensity in the gill of the mussels collected
at different sites and found a higher intensity in specimens collected from a site with higher sulfide concentration. We also
compared mussels reared in the presence and absence of sulfide and found that the former had a higher fluorescent intensity. 相似文献
46.
Koichi CHIKUNI Mika OE Keisuke SASAKI Masahiro SHIBATA Ikuyo NAKAJIMA Koichi OJIMA Susumu MUROYA 《Animal Science Journal》2010,81(5):600-605
To assess the role of muscle fiber type in beef taste‐traits, we analyzed cooked meats from bovine masseter, diaphragm, psoas major, longissimus thoracis, and semitendinosus muscles with an electric taste sensing system (INSENT SA402B). The system is composed of five taste sensors of polymer membranes fixing different lipids. The sensors, CT0, CA0, AAE, C00 and AE1 are designed to respond to the individual tastes of salty, sour, umami, bitter and astringent, respectively. The system found significant differences in the converted outputs of CA0 (cvCA0), C00 (cvC00) and AE1 (cvAE1) among the bovine muscles. The slow‐type muscles (masseter and diaphragm) showed lower cvCA0, higher cvC00, and higher cvAE1 than did the fast‐type muscles (psoas major, longissimus thoracis, and semitendinosus). Lactic acid content was different among muscle types and was highly related to the cvCA0 output and pH. carbonyl compounds and free fatty acids were higher in the slow‐type muscles. Free fatty acids were major components causing the difference in the C00 output among the muscle types. Iron content was also different among the muscle types and related to the cvC00 and cvAE1 outputs. These results suggested that the muscle fiber type affects the beef taste characteristics. 相似文献
47.
Abstract Hattori (1985) proposed a model to simulate the relation between the number of bacterial colonies on agar plates and the incubation time, using the following equation: where N(t) is the number of colonies observed at time t, and N∞ λ, and t r are parameters expressing the expected number of colonies observed at an infinite time, the rate of increase in the number of colonies, and the time of initiation of colony formation, respectively. This model is called the first-order reaction (FOR) model because the Eq. 1 is essentially the same as that of the first-order reaction. 相似文献
48.
Takafumi Inoue Tsutomu Enoki Naoaki Tashiro Kotaro Sakuta Susumu Inoue 《Journal of Forest Research》2008,13(6):365-371
We investigated factors affecting the distribution of naturally regenerated broad-leaved trees in a 140-year-old Cryptomeria japonica plantation. We used path analysis to examine the relationship among microtopography, the biomass of planted trees, and the
biomasses of canopy and subcanopy trees of broad-leaved species. The study plot was divided into three topographic types (ridge,
slope, and valley), and we discuss how the different topographic types are affected. For all topographic types, the biomass
of canopy trees of broad-leaved species decreased with convexity. For slope and valley topographies, the biomass of subcanopy
trees of broad-leaved species also decreased with convexity. For ridge topography, the biomass of subcanopy trees of broad-leaved
species increased with the biomass of planted trees, and decreased with the biomass of canopy trees of broad-leaved species.
These results suggest the effects of microtopography on the biomass of subcanopy trees were much larger than the effects of
canopy trees for slope and valley topographies, while the effects of microtopography were smaller for ridge topography. 相似文献
49.
Keiko Uchida Susumu Takamatsu Sanae Matsuda Kazuhiro So Yukio Sato 《Journal of General Plant Pathology》2009,75(2):92-100
In 2002, a powdery mildew with catenate conidia lacking fibrosin bodies was found on cucumber in a greenhouse in Kanagawa
Prefecture, Japan. Morphological observation revealed that the fungus belongs to Oidium subgenus Reticuloidium, anamorph of the genus Golovinomyces. Molecular phylogenetic analyses of the nucleotide sequences of the rDNA ITS regions and D1/D2 domains of the 28S rDNA indicated
that the fungus belongs to the clade of G. orontii with other Golovinomyces fungi from a wide range of host plants, suggesting that the fungus was newly transported from abroad. Because there has been
no prior report of cucumber powdery mildew caused by Reticuloidium, further research on the physiology, epidemiology, control and resistant cucumber varieties is required. 相似文献
50.
Genetic variation in the height growth curves was investigated by analyzing data from three clonal trials of sugi (Crytomeria japonica D. Don) in Kyushu. Average height of twelve clones measured at each of five years until 30 years of age were fitted to the
Chapman-Richards function with two parameters model. Clonal variation in the two parameters (an upper asymptote and a rate
of growth parameter) was statistically significant across the tests, indicating that height growth pattern is under genetic
control. The type of growth curve was clearly classified with the two parameters and agreed with the empirical classifications
of the growth habit of local varieties. The rate of growth parameter was correlated with total height up to 20 years of age,
while the upper asymptote was correlated only with the last ten years’ increment from 21 to 30 years where the clonal repeatability
was decreasing. This indicates that a clonal selection for long rotation management system would not be reliable unless the
height is measured accurately with more advanced devices or it is adjusted by the current increment of diameter. 相似文献