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排序方式: 共有153条查询结果,搜索用时 15 毫秒
101.
Tetsushi HIRANO Shogo YANAI Takuya OMOTEHARA Rie HASHIMOTO Yuria UMEMURA Naoto KUBOTA Kiichi MINAMI Daichi NAGAHARA Eiko MATSUO Yoshiko AIHARA Ryota SHINOHARA Tomoyuki FURUYASHIKI Youhei MANTANI Toshifumi YOKOYAMA Hiroshi KITAGAWA Nobuhiko HOSHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(10):1207-1215
Neonicotinoids, some of the most widely used pesticides in the world, act as agonists to
the nicotinic acetylcholine receptors (nAChRs) of insects, resulting in death from
abnormal excitability. Neonicotinoids unexpectedly became a major topic as a compelling
cause of honeybee colony collapse disorder, which is damaging crop production that
requires pollination worldwide. Mammal nAChRs appear to have a certain affinity for
neonicotinoids with lower levels than those of insects; there is thus rising concern about
unpredictable adverse effects of neonicotinoids on vertebrates. We hypothesized that the
effects of neonicotinoids would be enhanced under a chronic stressed condition, which is
known to alter the expression of targets of neonicotinoids, i.e.,
neuronal nAChRs. We performed immunohistochemical and behavioral analyses in male mice
actively administered a neonicotinoid, clothianidin (CTD; 0, 10, 50 and 250 mg/kg/day),
for 4 weeks under an unpredictable chronic stress procedure. Vacuolated seminiferous
epithelia and a decrease in the immunoreactivity of the antioxidant enzyme glutathione
peroxidase 4 were observed in the testes of the CTD+stress mice. In an open field test,
although the locomotor activities were not affected, the anxiety-like behaviors of the
mice were elevated by both CTD and stress. The present study demonstrates that the
behavioral and reproductive effects of CTD become more serious in combination with
environmental stress, which may reflect our actual situation of multiple exposure. 相似文献
102.
Dennis S. Ojima William J. Parton David S. Schimel Jonathan M. O. Scurlock Timothy G. F. Kittel 《Water, air, and soil pollution》1993,70(1-4):643-657
We present results from analyses of the sensitivity of global grassland ecosystems to modified climate and atmospheric CO2 levels. We assess 31 grassland sites from around the world under two different General Circulation Models (GCM) double CO2 climates. These grasslands are representative of mostly naturally occurring ecosystems, however, in many regions of the world, grasslands have been greatly modified by recent land use changes. In this paper we focus on the ecosystem dynamics of natural grasslands. The climate change results indicate that simulated soil C losses occur in all but one grassland ecoregion, ranging from 0 to 14% of current soil C levels for the surface 20 cm. The Eurasian grasslands lost the greatest amount of soil C (~1200 g C m?2) and the other temperate grasslands losses ranged from 0 to 1000 g C m?2, averaging approximately 350 g C m?2. The tropical grasslands and savannas lost the least amount of soil C per unit area ranging from no change to 300 g C m?2 losses, averaging approximately 70 g C m?2. Plant production varies according to modifications in rainfall under the altered climate and to altered nitrogen mineralization rates. The two GCM's differed in predictions of rainfall with a doubling of CO2, and these differences are reflected in plant production. Soil decomposition rates responded most predictably to changes in temperature. Direct CO2 enhancement effects on decomposition and plant production tended to reduce the net impact of climate alterations alone. 相似文献
103.
104.
105.
SUMMARY: Five clonal lines of silver crucian carp Carassius langsdorfii were produced from natural maternal fish to estimate the variance and heritability of total length, bodyweight and gonadosomatic index (GSI). The larvae on the 10th day after hatching were reared together in a common rearing system with five duplicate systems. Another system was prepared using a separate system with two replications in each family. Estimation of variance and heritability were done in the first, third, fifth and 10th month for total length and bodyweight. Microsatellite DNA markers were used to identify the clonal lines in each communal rearing tank. Average heritabilities in the first month were 0.105 for total length (ranging from 0.21 to 0.03) and 0.127 for bodyweight (ranging from 0.22 to 0.06) then decreased in the third, fifth and 10th month. In contrast, intermediate levels of heritability from separate systems were observed. Likewise, relative heritability of GSI in the 10th month presented a high level in both rearing systems. Those heritabilities indicated that growth, total length, bodyweight and reproductive performances of silver crucian carp were affected by genetic influence. The results suggest that clonal lines of silver crucian carp are suitable as experimental animals for evaluations of environmental change and various pollutants through quantitative traits such as growth, reproductive and other physiological traits. 相似文献
106.
The mid-gut gland of scallop Patinopecten yessoensis has been discarded in scallop processing factories as a fishery waste and various attempts have been made to turn the waste
into valuable resources. In the present study, we tried to use mid-gut gland drips from scallop as a source of β-1,3-glucanase.
The mid-gut gland drips were collected in a local fishery factory in Yubetsu-cho, Hokkaido Prefecture. β-1,3-Glucanase was
purified from the mid-gut gland drips by ammonium sulfate fractionation followed by successive chromatography on Toyopearl
Phenyl-650M and Toyopearl DEAE-650M. The scallop β-1,3-glucanase, named PyLam38 in the present study, showed a molecular mass
of approximately 38 kDa by sodium dodecylsulfate-polyacrylamide gel electrophoresis, and hydrolyzed laminarin, a β-1,3-glucan
from Laminaria sp., producing laminaribiose and glucose with an optimal pH and temperature of 6.0 and 45°C, respectively. PyLam38 exhibited
high transglycosylation activity toward various accepter substrates such as monosaccharides, alcohols and xylooligosaccharides.
Thus, PyLam38 was found to be useful for the production of various novel heterooligosaccharides consisting of laminarioligosaccharides
and various accepters. 相似文献
107.
Watabe Shugo Ikeda Daisuke Mashiro Takaki Kagetakubo Yuko Takahashi Yoshihiro Uemura Misaki Mizusawa Nanami Koyama Hiroki Yasumoto Ko Jimbo Mitsuru Kan-no Nobuhiro Ueda Tomohiro Matsuoka Yoko Ueki Nobuhiko Wan Jianrong 《Fisheries Science》2020,86(4):711-719
Fisheries Science - Complementary DNA encoding a part of myosin heavy chain was cloned from fast skeletal muscle of Japanese codling Physiculus japonicus. Japanese codling, a frequent catch off the... 相似文献
108.
Maria Rowena R Romana-Eguia Minoru Ikeda Zubaida U Basiao & Nobuhiko Taniguchi 《Aquaculture Research》2005,36(1):69-78
Two control (C1 or first control generation, and C4 or fourth control generation) and three selected (S1 or first selected generation, S2 or second selected generation, S4 or fourth selected generation) stocks of Chitralada Nile tilapia were analysed for microsatellite variation to determine the effect of size‐specific mass selection on genetic variability. Genetic variation based on five microsatellite loci (UNH123, UNH147, UNH172, UNH222 and UNH216) showed a slightly higher allelic diversity in the selected stocks (7.4–10 alleles) than in the control stocks (6.8–8.8 alleles). Apparent reductions in the mean number of alleles and He values were noted in successive generations of both control and selected lines. Significant deviations from Hardy–Weinberg equilibrium because of an excess of homozygotes indicated inbreeding in all control and selected stocks. Although estimated inbreeding levels were not significantly different among selected and control lines based on Welch's t‐tests, the increase in the degree of inbreeding within the selected line was higher (107.9%) than the control line (64.2%) after four generations. The implications of these results on the management and conservation of genetic diversity in improved breeds are discussed, while the importance of monitoring and minimizing inbreeding are likewise emphasized. 相似文献
109.
Previously we isolated the major alginate lyase isozyme LbAly35 from a marine snail Littorina brevicula and showed that this enzyme was significantly heat stable in a broad pH range compared with other molluscan alginate lyases (Hata et al., Fish Sci 75:755?C763, 2009). LbAly35 showed practically no similarity to other molluscan alginate lyases in the N-terminal amino-acid sequence of 20 residues and no cross-reactivity with anti-abalone alginate lyase antiserum. These led us to consider that the primary structure of LbAly35 is considerably deviated from other molluscan enzymes. Thus, in the present study, we first compared the thermal stability of LbAly35 with an abalone alginate lyase, HdAly, and found that the first order inactivation rate constants for LbAly35 at 40 and 45?°C were 1/20 and 1/45 of those for HdAly, respectively. Then, we cloned cDNAs encoding LbAly35 and characterized its deduced amino-acid sequence comparing with those of other molluscan alginate lyases. The cDNAs were amplified by polymerase chain reaction (PCR) and 5??- and 3??-RACE PCRs from the L. brevicula hepatopancreas cDNA using degenerated primers synthesized on the basis of partial amino-acid sequences of LbAly35. The cDNA covering the entire translational region of LbAly35 comprised 1,093?bp and encoded an amino-acid sequence of 296 residues. The amino-acid sequence consisted of an initiation methionine, a putative signal peptide for secretion (22 residues), a propeptide-like region (10 residues), and a mature LbAly35 domain of 263 residues. Although the N-terminal region of LbAly35 was significantly deviated from those of other molluscan alginate lyases, the catalytic domain of LbAly35 showed ~45?% identity to other molluscan enzymes which had been classified under polysaccharide-lyase-family-14 (PL-14). In addition, the amino-acid residues crucially important for the catalytic actions of PL-14 enzymes were also conserved in LbAly35. Accordingly, LbAly35 was regarded as a member of PL-14 as other molluscan alginate lyases despite the significant deviation of its N-terminal region. 相似文献
110.
Syuto Hasegawa Kazuhiro Ura Hiroyuki Tanaka Takao Ojima Yasuaki Takagi 《Fisheries Science》2012,78(5):1107-1115
We isolated a cellulase from the digestive organs of the short-spined sea urchin Strogylocentrotus intermedius using a combination of ion-exchange chromatography and gel filtration together with an assay for carboxymethylcellulase activity. The isolated cellulase was stained as a single band by Congo red. The molecular weight of the isolated cellulase, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions, was 59?kDa. The isolated cellulase exhibited hydrolytic activity toward carboxymethyl cellulose, with an optimum temperature and pH of 30?°C and pH 8.0, respectively. The thermal stability of the enzyme was characterized by determining the temperature at which activity decreased by 50?% with treatment for 30?min at pH 7.0 and found to be 32?°C. Cellulase activity remained at a high level at 5?C20?°C, which is the growth temperature of the short-spined sea urchin. These results confirm that the short-spined sea urchin should preferably be reared at a water temperature of <20?°C. 相似文献