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11.
Regular sea urchins, which have pentaradial symmetry, have been believed to show no preference in which part of the body forward
they proceed with. Through use of circular statistics, we show that the regular sea urchin Hemicentrotus pulcherrimus had no preference with respect to what body part, as determined by Lovén’s system, should be anterior in locomotion. The
sea urchins, however, preferably proceeded with the body part, which had contacted with the aquarium walls at rest, forward.
When the contact part was artificially altered, the body part facing forward in the following proceeding changed accordingly:
the animals walked with the part that had contacted last forward. The biological significance of this behavior was discussed
in relation to the aggregation formation and homing behavior. 相似文献
12.
Sakie Miyazaki Kazuhei Takahashi Mari Shiraki Terumi Saito Yoko Tezuka Ken-ichi Kasuya 《Journal of Polymers and the Environment》2000,8(4):175-182
A poly(3-hydroxybutyrate) (PHB) depolymerase was purified from a fungus, Penicillium funiculosum (IFO6345), with phenyl-Toyopearl and its properties were compared with those of other PHB depolymerases. The molecular mass of the purified enzyme was estimated at about 33 kDa by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The pH optimum and pI were 6.5 and 6.5, respectively. The purified protein showed affinity to Con A-Sepharose, indicating that it is a glycoprotein. Diisopropylfluorophosphate and dithiothreitol inhibited the depolymerase activity completely. The N-terminal amino acid sequence of the purified enzyme was TALPAFNVNPNSVSVSGLSSGGYMAAQL, which contained a lipase box sequence. This purified enzyme is one of the extracellular PHB depolymerase which belong to serine esterase. The purified enzyme showed relatively strong hydrolytic activity against 3-hydroxybutyrate oligomers compared with its PHB-degrading activity. PHB-binding experiments showed that P. funiculosum depolymerase has the weakest affinity for PHB of all the depolymerases examined. 相似文献
13.
Vagile animals usually have bilaterally symmetrical bodies and proceed with their mouth-end first. Regular sea urchins have,
however, radially symmetrical bodies with their mouth facing the substratum and show no preference in which side of the body
should be anterior in their locomotion. The elliptical sea urchins in the subfamily Echinometrinae are exceptional among regular
sea urchins in having elongated bilateral bodies. We studied whether they showed the preference in the direction of locomotion
using Echinometra sp. type A. Directional preference was not observed in the proceedings in an open space. However, they proceeded preferentially
with their long axis coinciding with the direction of locomotion when they moved along the water surface or along the wall
of the aquarium. The speed of locomotion was the same irrespective of the direction of proceedings and of whether sea urchins
moved freely or moved along the water surface or along the walls. We suggest that the bilateral body form and the habit of
long-axis lead of this sea urchin have adaptive significance to increase the protected body surfaces, not to facilitate the
efficiency in locomotion. 相似文献
14.
Kensuke Miyazaki Noriyasu Okazaki Minoru Terano Hisayuki Nakatani 《Journal of Polymers and the Environment》2008,16(4):267-275
In this work, an oxidatively degraded polypropylene (DgPP) was studied as a novel coupling agent for fibrous cellulose (FC)/polypropylene
(PP) composite. An optimal preparation time of PP thermal oxidative degradation was 18 h at 130 °C, and the DgPP had functional
groups such as γ-lactone and acid groups. The spherulite observation of the DgPP suggested miscibility for the undegraded
PP. The addition of the DgPP presented the transparency improvement of FC/PP composite, and this behavior was found to be
originated from the grafted DgPP, which was produced by the esterification reaction between the of FC and the DgPP. The scanning
electron microscope (SEM) observation showed that the grafted DgPP coated the FC surface, and the tensile strength of the
FC/PP composite increased by an appropriate amount of the DgPP addition. These results suggested that the DgPP was suitable
for the coupling agent of FC/PP composite. 相似文献
15.
In order to determine competency of sexual reproduction and survival rate after fragmentation, the branching coral Acropora formosa was fragmented and fragments in three different sizes (ca. 5, 10 and 20 cm long) and three different stages of gametogenesis
were transplanted on coral pavement. Their oocyte development and fecundity, as well as spawning were monitored for a 3-year
period. The oocyte development was affected by both fragment size and by the developmental stage of oocytes when fragmented.
In small fragments, the oocytes were resorbed while in large fragments they continued development. Oocytes in the early vitellogenic
stage at the time of fragmentation were resorbed, whereas those in the late stage continued developing. Smaller fragments
showed a lower survival rate and histological observations of their gonads revealed resorption of oocytes, suggesting that
there was a trade-off of energy between reproduction and survival. Transplanted fragments often spawned one month earlier
than the donor colonies in the first year, but spawning occurred in the same month as the donors or did not occur at all in
the second year and none spawned in the third year. The risk of colony death may cause the fragments to re-allocate energy
for sexual reproduction. 相似文献
16.
Acute toxicity of chlorophenols to earthworms using a simple paper contact method and comparison with toxicities to fresh water organisms 总被引:5,自引:0,他引:5
An acute toxicity test of chlorophenols on earthworms (Eisenia fetida) was performed using a simple paper contact method proposed by OECD testing guideline no. 207, that were applied as an earthworm toxicity test. The median lethal concentration, EC50, had significant correlation with logP(ow) (1-octanol/water partition coefficient) of the chemicals. The toxicity of chlorophenols on E. fetida was compared with toxicities for other species: an algae (Selenostrum capricornutum), a crustacean (Daphnia magna), and a fish (Oryzias latipes). It was found that the toxicity of chlorophenols was almost same for E. fetida and for fresh water organisms. These results suggest the possibility of drawing correlations between the effects of pollutants on living things in different environments, fresh water and soil. 相似文献
17.
Nakata H Sakakibara A Kanoh M Kudo S Watanabe H Nagai N Miyazaki N Asano Y Tanabe S 《Environmental pollution (Barking, Essex : 1987)》2002,120(2):245-253
The effects of exposure to butyltin compounds (BTs: tributyltin; TBT, dibutyltin; DBT and monobutyltin; MBT) and non-ortho coplanar PCBs (IUPAC 77, 126 and 169) on marine mammals and human lymphocyte were evaluated. Peripheral blood mononuclear cells (PBMCs) isolated from Dall's porpoises (Phocoenoides dalli), bottlenose dolphins (Tursiops truncatus), a California sealion (Zalophus californianus), a larga seal (Phocoa largha) and humans (Homo sapiens) were exposed at varying concentrations of BTs and coplanar PCBs. Concanavalin A (Con A)-stimulated mitogenesis found significantly suppressed (P<0.01) when the cells were exposed at 300 nM (89 ng/ml) of TBT and 330 nM of DBT (77 ng/ml), while MBT showed little cytotoxicity at treatment levels of up to 3,600 nM (620 ng/ml). BTs concentrations in the liver of Dall's porpoises from Japanese coastal waters ranged between 81-450 ng/g for TBT and 200-1,100 ng/g (wet wt.) for DBTs, which is greater than the cytotoxic levels registered in this study. In contrast, non-ortho coplanar PCBs did not suppress cell proliferation at concentrations of up to 30 nM (10 ng/ml). The residue levels of coplanar PCBs in the blubber of Dall's porpoises were 0.12-1.3 ng/g, which were one order of lower than those levels that do cell proliferation. When cells were exposed to a mixture of TBT/DBTand coplanar PCBs, the proliferation was significantly reduced to 33 nM DBT plus 34 nM CB-77 and 33 nM DBT plus 28 nM CB-169 mixtures, respectively. The investigations relating the contaminant-induced immunosuppression in marine mammals have been focused on persistent organochlorines such as PCBs. pesticides and dioxin compounds. However, this study suggested the possibility of BTs could also pose a serious threat to the immune functions in free-ranging marine mammals and humans. 相似文献
18.
R. Xiao N. Takegawa Y. Kondo Y. Miyazaki T. Miyakawa M. Hu M. Shao L.M. Zeng A. Hofzumahaus F. Holland K. Lu N. Sugimoto Y. Zhao Y.H. Zhang 《Atmospheric environment (Oxford, England : 1994)》2009,43(24):3754-3763
Size-resolved chemical compositions of non-refractory submicron aerosols were measured using a quadrupole Aerodyne aerosol mass spectrometer at a rural site near Guangzhou in the Pearl River Delta (PRD) of China in the summer of 2006. Two cases characterized as the outflows from the PRD urban region with plumes of high SO2 concentration were investigated. The evolution of sulfate size distributions was observed on a timescale of several hours. Namely mass concentrations of sulfate in the condensation mode (with vacuum aerodynamic diameters (Dva) < 300 nm) increased at a rate of about 0.17–0.37 ppbv h?1 during the daytime. This finding was consistent with the sulfuric acid production rates of about 0.17–0.3 ppbv h?1, as calculated from the observed gas-phase concentrations of OH (~3.3 × 106–1.7 × 107 cm?3) and SO2 (~3–21.2 ppbv). This implies that the growth of sulfate in the condensation mode was mainly due to gas-phase oxidation of SO2. The observed rapid increase was caused mainly by the concurrent high concentrations of OH and SO2 in the air mass. The evolution of the mass size distributions of m/z 44, a tracer for oxygenated organic aerosol (OOA), was very similar to that of sulfate. The mass loadings of m/z 44 were strongly correlated with those of sulfate (r2 = 0.99) in the condensation mode, indicating that OOA might also be formed by the gas-phase oxidation of volatile organic compound (VOC) precursors. It is likely that sulfate and OOA were internally mixed throughout the whole size range in the air mass. 相似文献
19.
Kurokawa Daisuke Nakaguchi Ayuka Hirano Yoko Iida Tatsuo Mori Taiichiro Matsuzawa Kazuki Sakai Etsuo 《Journal of Material Cycles and Waste Management》2021,23(3):1270-1275
Journal of Material Cycles and Waste Management - This paper estimates the effects of a composition change of ordinary Portland cement on waste utilization and CO2 emissions in the Japanese cement... 相似文献
20.