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81.
Kawahara M Obata Y Sotomaru Y Shimozawa N Bao S Tsukadaira T Fukuda A Kono T 《Nature protocols》2008,3(2):197-209
A reliable nuclear transfer method was first reported in 1983; it provided definite evidence that parthenogenetic embryos are lethal at early postimplantation in mammals. Subsequently, nuclear transfer has been extensively used as an important and versatile tool for investigating embryo and somatic-cell cloning and nucleo-cytoplasmic interactions. Further development of this technique has enabled the generation of bimaternal embryos containing two haploid sets of maternal genomes from female germ cells of different origins. By using a 2-d nuclear transfer system for oocyte reconstruction, viable mice can be produced solely from maternal genomes, without the participation of the paternal genome. This oocyte reconstruction system, as described in this protocol, could provide valuable guidelines for exploring the potential endowments of gametes and for conferring novel properties to them. 相似文献
82.
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84.
Oba T Maeno Y Nagao M Sakuma N Murayama T 《American journal of physiology. Heart and circulatory physiology》2008,294(1):H121-H133
Recent studies indicate that low concentrations of acetaldehyde may function as the primary factor in alcoholic cardiomyopathy by disrupting Ca(2+) handling or disturbing cardiac excitation-contraction coupling. By producing reactive oxygen species, acetaldehyde shifts the intracellular redox potential from a reduced state to an oxidized state. We examined whether the redox state modulates acetaldehyde-induced Ca(2+) handling by measuring Ca(2+) transient using a confocal imaging system and single ryanodine receptor type 2 (RyR2) channel activity using the planar lipid bilayer method. Ca(2+) transient was recorded in isolated rat ventricular myocytes with incorporated fluo 3. Intracellular reduced glutathione level was estimated using the monochlorobimane fluorometric method. Acetaldehyde at 1 and 10 microM increased Ca(2+) transient amplitude and its relative area in intact myocytes, but acetaldehyde at 100 microM decreased Ca(2+) transient area significantly. Acetaldehyde showed a minor effect on Ca(2+) transient in myocytes in which intracellular reduced glutathione content had been decreased against challenge of diethylmaleate to a level comparable to that induced by exposure to approximately 50 microM acetaldehyde. Channel activity of the RyR2 with slightly reduced cytoplasmic redox potential from near resting state (-213 mV) or without redox fixation was augmented by all concentrations of acetaldehyde (1-100 microM) used here. However, acetaldehyde failed to activate the RyR2 channel, when the cytoplasmic redox potential was kept with a reduced (-230 mV) or markedly oxidized (-180 mV) state. This result was similar to effects of acetaldehyde on Ca(2+) transient in diethylmaleate-treated myocytes, probably being in oxidized redox potential. The present results suggest that acetaldehyde acts as an RyR2 activator to disturb cardiac muscle function, and redox potential protects the heart from acetaldehyde-induced alterations in myocytes. 相似文献
85.
Cartilage link protein interacts with neurocan, which shows hyaluronan binding characteristics different from CD44 and TSG-6 总被引:2,自引:0,他引:2
Uwe Rauch Satoshi Hirakawa Toshitaka Oohashi Joachim Kappler Gunnel Roos 《Matrix biology》2004,22(8):221-639
The interaction of neurocan with hyaluronan was qualitatively characterized with alkaline phosphatase fusion proteins secreted by mammalian cells. The wild type neurocan hyaluronan binding domain fused to alkaline phosphatase bound to immobilized hyaluronan under physiological as well as moderately hypertonic conditions, whereas its ability to bind to immobilized chondroitin sulfate dropped rapidly with increasing salt concentration. Strong hyaluronan binding ability was still evident when in both link modules within the hyaluronan binding domain a basic amino acid was mutated, which is well conserved among link modules of hyaluronan binding proteins. A strong enhancement of the binding of neurocan to immobilized hyaluronan was observed after preincubation of the immobilized hyaluronan with cartilage link protein. Moreover, this preincubation mediated also the binding of a fusion protein representing only the immunoglobulin module of neurocan linked to alkaline phosphatase, which showed no binding to immobilized hyaluronan alone. The interaction of the neurocan immunoglobulin module with link protein could also be shown by overlay blot analysis. These observations suggest that the hyaluronan binding characteristics of paired link modules are different from those of single link modules, and that the reported temporal co-expression of cartilage link protein and of neurocan in developing brain implicates the possibility of a cooperative function of these molecules. 相似文献
86.
H. Takami Yoshihiro Takaki Kaoru Nakasone Tokuki Sakiyama G. Maeno Rumie Sasaki Chie Hirama Fumie Fuji Noriaki Masui 《Extremophiles : life under extreme conditions》1999,3(3):227-233
Seventeen Sse8387I linking clones isolated from the chromosome of Bacillus halodurans C-125 for the purpose of constructing a physical map were sequenced and analyzed by comparison with the BSORF database and
the nonredundant protein databank. The orientations of Sse8387I or AscI linking clones serving to join adjacent fragments were determined by southern blot analysis using specific DNA probes. One-third
of the open reading frames (ORFs) identified in the Sse8387I linking clones showed no significant similarity to any protein so far reported. The ORFs showing significant similarities
to those of Bacillus subtilis were mapped in the chromosome of strain C-125, and the locations of the putative genes on the map were not well conserved
between B. halodurans C-125 and B. subtilis.
Received: March 26, 1999 / Accepted: April 27, 1999 相似文献
87.
Koh-ichi Enomoto Kishio Furuya Shunichi Yamagishi Takashi Maeno 《Cell biochemistry and function》1993,11(1):55-62
Injection of D -myo-inositol-1,4,5-trisphosphate (IP3) was found to induce a transient increase of intracellular Ca2+ concentration in cancerous mammary cells (MMT060562) and in normal mammary cells treated with epidermal growth factor. Responses to injection of either D -myo-inositol-1,4-bisphosphate (IP2) or D -myo-inositol-1,3,4,5-tetrakisphosphate (IP4) were small or absent. Furthermore, normal mammary cells cultivated with low-protein serum replacement alone or in the presence of differentiation-inducing hormones (insulin + cortisol + prolactin) were less sensitive to IP3. Thapsigargin induced a transient increase of Ca2+ due to the release of Ca2+ from an intracellular pool. There was no difference in the peak heights of the thapsigargin-induced Ca2+ increase when mammary cells were cultivated in the presence or absence of epidermal growth factor or insulin + cortisol + prolactin. These findings suggest that the releasable intracellular Ca2+ pool remained unchanged whereas sensitivity to IP3 increases during the proliferation stage. Mechanical stimulus of a mammary cell induces an increase of intracellular Ca2+ in the stimulated cell. A certain stimulating factor is released from the mechanically stimulated cell into the extracellular space, and it induces an increase of Ca2+ in surrounding cells.18 In contrast, the IP3-induced Ca2+ increase in both cancerous and epidermal growth factor-treated normal mammary cells did not spread to adjacent cells. Therefore, increase of Ca2+ is not sufficient to account for the release of stimulating substances from mammary cells in the mechanically-induced spreading response. 相似文献
88.
Itoh Hiroya Miura Ai Matsui Makoto Arazoe Takayuki Nishida Keiji Kumagai Toshitaka Arita Masanori Tamano Koichi Machida Masayuki Shibata Takashi 《Applied microbiology and biotechnology》2018,102(3):1393-1405
Applied Microbiology and Biotechnology - In the production of useful microbial secondary metabolites, the breeding of strains is generally performed by random mutagenesis. However, because random... 相似文献
89.
There have been no reports of infanticide in wild gelada baboons and it has been argued that infanticide is not necessary
in geladas, since the birth interval of female gelada can be shortened after takeover of a unit by a new leader male without
infanticide. However, we observed an instance of infanticide in a newly-found wild gelada population in the Arsi Region of
Ethiopia.
After a leader male of the unit was severely wounded by a leopard attack, he was quite weakened. The second male of the unit,
a young adult male, became the leader of the unit three weeks later, but the former leader continued to stay in the unit as
a second male. After a week, two other adult males joined the unit which, therefore, came to include four adult males. The
infanticide took place nine days later. The perpetrator was one of the immigrant males and he showed great interest in the
mother of the unweaned victim infant. Although the perpetrator copulated with her after the infanticide, the usurper was found
to own all three adult females after two weeks following the infanticide; i.e. the perpetrator could not own any female. The
wounded former leader showed conspicuous protective behavior towards the victim's mother and the dead infant.
One possible explanation for the occurrence of infanticide in this population of geladas is as follows. Gelada males in this
area may be able to join units more easily to form multi-male units but then have shorter tenure in the units. Facing the
unstable condition of units, they may sometimes engage in infanticide to increase their breeding opportunities, even before
becoming a leader. 相似文献
90.