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61.
Masato Kobayashi Tomohito Shimizu Koichi Okuzawa Kiyoshi Soyano Kenzo Yoseda 《Fisheries Science》2010,76(5):777-784
To determine the sexual maturity of fourteen male wild-caught hawksbill turtles [straight carapace length (SCL) range 63–79 cm]
held in captivity, we investigated their hormone levels in blood and morphological characteristics. Male turtles were divided
into two groups: five individuals showing mating behavior (group A) and nine individuals not showing mating behavior (group B).
Then, seasonal changes of plasma testosterone of both groups were studied. We also tried to determine male maturity based
on tail elongation (TE) index, i.e., the ratio of tail length (TL) to SCL. Plasma testosterone level of group A gradually
increased during premating and then sharply declined to low levels between mating and postmating seasons. In contrast, that
of group B remained low during the experimental periods. The distinct seasonal changes of plasma testosterone levels of groups A
and B correlated with their maturity. Furthermore, males were clearly divided into mature and immature based on TE values
>0.35 and <0.33, respectively, corresponding to results based on plasma testosterone levels. Our results indicate that TE
can be used more conveniently and accurately to determine maturity of male hawksbill turtles in captivity. 相似文献
62.
Astrid ARDIYANTI Yoshie OKI Yoshihito SUDA Keiichi SUZUKI Koichi CHIKUNI Yoshiaki OBARA Kazuo KATOH 《Animal Science Journal》2009,80(1):62-69
To investigate the effects of bovine growth hormone (bGH) gene polymorphism on carcass traits and fatty acid compositions in Japanese Black cattle caused by nucleotide substitution of CTG (allele A)/GTG (allele B) at codon 127 and of ACG (allele A and B)/ATG (allele C) at codon 172 of bGH, GH genotypes of 135 cattle were determined using allele specific-multiplex polymerase chain reaction (PCR). Allele A gave greater rib thickness and lower melting point of fat (MP) while allele B gave higher C18:1% ( P < 0.05). Allele C gave higher C18:1, monounsaturated fatty acid (MUFA), unsaturated fatty acid (USFA) percentages ( P < 0.05). It also gave lower saturated fatty acid (SFA) percentages, higher MUFA/SFA and USFA/SFA ratios, and lower MP ( P < 0.05). Interactions of sex and GH alleles were analyzed. In heifers, allele A gave higher carcass weight, daily carcass gain, rib eye area, rib thickness, subcutaneous fat thickness, and BMS while allele B gave greater rib eye area and rib thickness ( P < 0.05). Allele C gave higher C18:1 ( P < 0.01), MUFA ( P < 0.01), USFA percentages ( P < 0.05) and MUFA/SFA and USFA/SFA ratios ( P < 0.01), and lower C16:0 and SFA percentages ( P < 0.05) and MP ( P < 0.01). GH gene polymorphism affected carcass traits and fatty acid compositions although the effects were more pronounced in heifers. 相似文献
63.
Yasunaga YOSHIKAWA Masami MORIMATSU Kazuhiko OCHIAI Toshina ISHIGURO-OONUMA Ryo MORIOKA Kento OKUDA Koichi ORINO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(5):759
Mammary tumors are the most common tumors in women and non-spayed female dogs. One of the reasons for mammary tumors is mutations of the tumor suppressor gene, BRCA2. BRCA2 participates in homologous recombination repair by interacting with the RAD51 recombinase. BRCA2 has two RAD51-binding domains, consisting of BRC repeats and the C-terminal RAD51-binding domain, respectively. Although several studies have addressed the function of the C-terminal RAD51-binding domain of human BRCA2, the amino acid sequences required for the RAD51-interaction activity remain unclear. In this study, the C-terminal RAD51-binding domains of canine and human BRCA2 were compared; the canine domain displayed a weaker interaction with RAD51. This difference was attributed to the C-terminal portion of the domain via a comparison between canine and human domains. Furthermore, peptides shorter than those previously reported displayed RAD51-interacting activity, and a core motif of this domain consisting of 25 amino acids was identified. Since a mutation (S3323N) was reported in the core motif of this domain, the effect of this mutation was evaluated. The mutant exhibited similar RAD51-binding activity as that of the wild-type protein, suggesting that the mutation was functionally neutral. These data suggested that the C-terminal portion of the BRCA2 C-terminal RAD51-binding domain influenced its RAD51-interaction activity, and a minimum core motif of 25 amino acids was identified in this domain. These data may help clarify BRCA2 function, as well as the tumorigenic effects of BRCA2 mutation. 相似文献
64.
Toshinao Ineno Koichi Tamaki Kazuya Yamada Ryusuke Kodama Shuji Tsuchida Engkong Tan Shigeharu Kinoshita Koji Muto Takashi Yada Shoji Kitamura Shuichi Asakawa Shugo Watabe 《Fisheries Science》2018,84(4):671-679
A thermally selected strain of rainbow trout has been established by selective breeding since 1966 in Miyazaki, Japan. In the present study, we compared the critical thermal maxima (CTMs), the temperatures at which organisms reach a predefined sublethal endpoint and lose their equilibrium, between a thermally selected and two normal (Donaldson) strains of rainbow trout. The CTM of one normal strain from Nikko (Nikko strain) acclimated to 20 °C (29.7 °C) was significantly lower than those of the thermally selected strain (30.0 °C) and the other Donaldson strain from Aomori (29.9 °C) (P?<?0.05). The F1 generations, F1T and F1N, were produced by crossing thermally selected strain females with Nikko strain males and Nikko strain females with thermally selected strain males, respectively. No significant difference was observed in the CTM between F1T [30.1?±?0.15 °C (n?=?30)] and F1N [30.1?±?0.16 °C (n?=?30)] (P?>?0.05) for fish acclimated to 20 °C, suggesting that the F1 offspring inherited the thermal tolerance trait from one thermally selected strain parent irrespective of whether it was the male or female. F2 offspring of F1T or F1N also showed the thermal tolerance trait. The coefficients of variation for CTM were also compared among all the datasets obtained in the present study and their values for F1 hybrids were lower than those of the parental generation of the Nikko strain (P?<?0.05). In contrast, the coefficients of variation of F2s were the same as those of their parental generation. Furthermore, the thermally selected strain and Nikko strain as a reference family provide a F2 generation for segregating phenotypes, which is required for in-depth genetic analysis of the thermally selected rainbow trout strain. 相似文献
65.
Go Suzuki Wataru Okada Youko Yasutake Sayaka Kai Yuji Fujikura Iwao Tanita Hiroshi Yamashita Takeshi Hayashibara Wataru Ando Koichi Nogami Masayuki Fudo 《Fisheries Science》2018,84(5):849-856
Extremely low post-settlement survival is one of the largest barriers for artificial rehabilitation of Acropora corals. However, little data have been found for interspecific difference of the post-settlement survival probably because the observation of coral juvenile is difficult in the field. Here, we analyzed the survival of three dominant species of Acropora corals (A. digitifera, A. tenuis, A. yongei), with different colony morphologies and habitat preferences, for 2 years after settlement under the same environmental conditions. The post-settlement survival was significantly higher for A. tenuis than for A. digitifera 3 months after settlement. Two years later, the survival rate of A. tenuis was approximately 15 times higher than A. digitifera. In a separate analysis of three bottle-brush species (A. awi, A. echinata, A. subglabra) and A. tenuis, post-settlement survival was always higher for A. awi than for other two bottle-brush species, suggesting that the initial survival was different among morphologically sister species. Low survival was possibly associated with slow growth rates during the first 7 months. Thus, species selection is important for successful artificial coral rehabilitation, with A. tenuis being the most viable option. Alternatively, new techniques are required to improve post-settlement survival of slow growing coral species. 相似文献
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69.
BACKGROUND: Botanical insecticides do not play a major role as crop protectants, but they are beneficial in some applications. The authors investigated the actions of naturally occurring alkaloids on insect nicotinic acetylcholine (ACh) receptors (nAChRs) by evaluating their abilities to inhibit specific binding of [3H]imidacloprid (IMI) to nerve‐cord membranes from Periplaneta americana L. Two alkaloids were also tested for their actions on nAChRs expressed by cockroach neurons using patch‐clamp electrophysiology. RESULTS: Four natural quinolizidine alkaloids (matrine, sophocarpine, cytisine and aloperine) exhibited more than 50% inhibition of [3H]IMI binding at 10 µM , although other compounds were found to have no or low inhibitory activity. The rank order of potency based on concentration–inhibition curves was cytisine > sophocarpine ≥ aloperine ≥ matrine. Patch‐clamp analysis indicated that sophocarpine and aloperine were not agonists of nAChRs expressed in P. americana neurons, yet, at 10 µM , aloperine, but not sophocarpine, suppressed ACh‐induced inward currents significantly. CONCLUSION: Three of the four natural alkaloids tested possess structural moieties that are necessary for interaction with P. americana nAChRs. Aloperine, which possesses a unique structure and showed a distinctive dose–response curve, was found to act as an antagonist. Appropriate modifications of these alkaloids might result in novel insecticidal nAChR ligands. Copyright © 2008 Society of Chemical Industry 相似文献
70.
Junichiro Takeuchi Toshihiko Kawachi Chie Imagawa Natsuki Buma Koichi Unami Shigeya Maeda 《Paddy and Water Environment》2010,8(2):145-156
A sophisticated modeling approach for simulating-coupled surface and subsurface flows in a watershed is presented. The watershed
model developed is a spatially distributed physically based model of composite dimension, consisting of 3-D variably saturated
groundwater flow submodel, 2-D overland flow submodel and 1-D river flow submodel. The 3-D subsurface flow is represented
by the complete Richards equation, while the 2-D and 1-D surface flows by the diffusive approximations of their complete dynamic
equations. For piecewise integration of these equations, the finite volume method (FVM) is employed assuming unknown variables
such as the water depth and the pressure head to be volume-averaged state ones. Problem plane geometry is meshed with the
unstructured cells of triangular shape which conforms to external as well as internal irregular boundaries such as those between
1-D and 2-D flows. A cell size controlling scheme, referred to as quasi-adaptive meshing scheme, is introduced to keep the
local discretization errors caused by topographic elevation gradient even over the entire-meshed geometry. Performance of
the model is tested through its practical application to a rugged intermountain watershed. Tuning the values of the three
key parameters ensures successful calibration of the model. Once the model is so calibrated, it could reproduce satisfactory
runoff response to any rainfall event. Expansion and shrinkage of the contributing area importantly affecting the direct runoff,
caused by the vicissitude of rainfall during its total duration, are well reproduced, like what the commonly accepted runoff
theory argues. It is thus concluded that the model developed could serve as a powerful watershed simulator usable for investigating
and assessing the hydrological aspect of a watershed. 相似文献