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排序方式: 共有479条查询结果,搜索用时 31 毫秒
71.
Keisuke Motone Toshiyuki Takagi Shunsuke Aburaya Wataru Aoki Natsuko Miura Hiroyoshi Minakuchi Haruko Takeyama Yukio Nagasaki Chuya Shinzato Mitsuyoshi Ueda 《Marine biotechnology (New York, N.Y.)》2018,20(4):542-548
Coral reefs are one of the most biologically diverse and economically important ecosystems on earth. However, the destruction of coral reefs has been reported worldwide owing to rising seawater temperature associated with global warming. In this study, we investigated the potential of a redox nanoparticle (RNPO) to scavenge reactive oxygen species (ROS), which are overproduced under heat stress and play a crucial role in causing coral mortality. When reef-building coral (Acropora tenuis) larvae, without algal symbionts, were exposed to thermal stress at 33 °C, RNPO treatment significantly increased the survival rate. Proteome analysis of coral larvae was performed using nano-liquid chromatography-tandem mass spectrometry for the first time. The results revealed that several proteins related to ROS-induced oxidative stress were specifically identified in A. tenuis larvae without RNPO treatment, whereas these proteins were absent in RNPO-treated larvae, which suggested that RNPO effectively scavenged ROS from A. tenuis larvae. Results from this study indicate that RNPO treatment can reduce ROS in aposymbiotic coral larvae and would be a promising approach for protecting corals from thermal stress. 相似文献
72.
Shin-ya Miyagishima Ryuuichi Itoh Kyoko Toda Haruko Kuroiwa Tsuneyoshi Kuroiwa 《Planta》1999,207(3):343-353
The time courses of chloroplast and mitochondrial division and the morphological changes in the plastid-dividing ring (PD
ring) and mitochondrion-dividing ring (MD ring) during chloroplast and mitochondrial division were studied in Cyanidioschyzon merolae De Luca, Taddei and Varano. To accomplish this, chloroplast and cell division of living cells were continuously video-recorded
under light microscopy, and the morphological changes in the PD and MD rings were analyzed quantitatively and three-dimensionally
by transmission electron microscopy (TEM). Under the light microscope, the diameters of the chloroplast and the cell decreased
at uniform velocities, the speed depending on the temperature. To study in detail the sequential morphological change of the
mitochondrion in M phase and the contractile mechanism in the divisional planes of the chloroplast and the mitochondrion,
we observed the PD and MD rings, which are believed to promote contraction, under TEM, using the diameter of the chloroplast
as an index of the time. Three PD rings (an outer PD ring on the cytoplasmic face of the outer envelope, a middle PD ring
in the intermembrane space, and an inner PD ring on the stromal face of the inner envelope) were clearly observed, but only
the outer MD ring could be observed. The PD ring started to contract soon after it formed, while the contraction of the MD
ring did not occur immediately after formation, but was delayed until the contraction of the PD ring was almost complete.
Once the MD ring began to contract, the rate of decrease of its circumference was 4 times as high as that of the PD ring.
As the outer PD and MD rings contracted, they grew thicker and maintained a constant volume, while the thickness of the inner
PD ring did not change and its volume decreased at a constant rate with contraction. In the early stage of contraction, the
widths of the three PD rings increased in order, from the outer to the inner ring. With contraction, their widths changed
at different rates until they came to have much the same width. In cross-section, the MD ring was wider where it was next
to the chloroplast than at the opposite side, adjacent to the nucleus in the early stage of contraction. By the late stage,
the widths of the two sides became equal. In our observations, the microbody elongated along the outer MD ring and touched
the outer PD ring during contraction of the PD and MD rings. These results clearly revealed differences between the mode of
contraction of the outer, middle, and inner PD rings, and between the PD and the MD rings. They also revealed the coordinated
widening of the three PD rings, and suggested that the microbody plays a role in the contraction of the PD and MD rings.
Received: 1 July 1998 / Accepted: 1 September 1998 相似文献
73.
Dimitri Pirottin Dominique Poncelet Luc Grobet Luis José Royo Benoit Brouwers Julio Masabanda Haruko Takeda Ruedi Fries Yoshikazu Sugimoto James E. Womack Susana Dunner Michel Georges 《Mammalian genome》1999,10(3):289-293
A closed YAC contig spanning the mh locus was assembled by STS content mapping with seven microsatellite markers, eight genes or EST, and nine STS corresponding
to YAC ends. The contig comprises 27 YACs, has an average depth of 4.3 YACs, and spans an estimated 1.2 Mb. A linkage map
was constructed based on five of the microsatellite markers anchored to the contig and shown to span 7 cM, yielding a ratio
of 160 kb/1 cM for the corresponding chromosome region. Comparative mapping data indicate that the constructed contig spans
an evolutionary breakpoint connecting two chromosome segments that are syntenic but not adjacent in the human. Consolidation
of human gene order by means of whole genome radiation hybrids and its comparison with the bovine order as inferred from the
contig confirm conservation of gene order within segments.
Received: 6 August 1998 / Accepted: 28 October 1998 相似文献
74.
Apoptosis of male germ cells is a widespread but little-understood phenomenon in many animal species. The elucidation of its mechanisms could be useful in the understanding of male infertility. We have examined the distribution of dying cells with the terminal transferase-mediated nick-end labeling (TUNEL) method and by an electron-microscopic procedure in the testes of 10 mouse strains, viz., C57BL/10 (B10), SL/NiA (SL), C57BL/6 (B6), C3H/He (C3H), BALB/c (BALB), DBA2 (DBA), CBA/J (CBA), MRL/MpJ(-)+/+ (M+), MRL/MpJ-lpr/lpr (lpr), and wild-type NJL mice (Mus musculus musculus). In the testes of the B10, NJL, SL, B6, C3H, BALB, DBA, and CBA mice, very few TUNEL-positive cells are distributed in the seminiferous tubules, whereas in the testes of the M+ and lpr mice, many TUNEL-positive cells, which are restricted to stage XII seminiferous tubules, have been identified. The most important finding is that many metaphases of meiotic spermatocytes show a marked TUNEL-positive reaction. Some metaphases show apoptotic morphology electron-microscopically. These results suggest that the testes of MRL strains will provide a useful model for the study of the mechanism of metaphase-specific apoptosis in meiotic spermatocytes. 相似文献
75.
Masahiko Hirata Nobumi Hasegawa Maki Nomura Haruko Ito Kangoro Nogami Tatsunobu Sonoda 《Ecological Research》2009,24(1):119-125
This study monitored deposition and decomposition of cattle dung in a grazed young Chamaecyparis obtusa (an evergreen conifer) plantation in southwestern Japan, as a part of exploring the impacts of livestock in the forest grazing
system. Animals defecated 10–19 times hd−1 day−1, producing feces of 2.2–3.5 kg DM and 33–73 g N per animal per day. The DM and N concentrations of feces ranged from 157–207 g DM kg−1 and 14.8−23.1 g (kg DM)−1, respectively. Occurrence of defecation was spatially heterogeneous, with feces being concentrated mainly on areas for resting
(forest roads, ridges and valleys) and moving (forest roads and along fence lines). Decomposition of dung pats was considerably
slow, showing the rates of 1.37–3.05 mg DM (g DM)−1 day−1 as DM loss. Decomposition was further slower on the basis of N release, 0.51–1.63 mg N (g N)−1 day−1, resulting in steadily increased N concentrations of dung pats with time after deposition. The results show that introduction
of livestock into a forest (i.e., forest grazing) may limit nutrient availability to plants, by redistributing nutrients into
areas with no vegetation (bare land and streams) and by establishing a large N pool as feces due to an imbalance between deposition
and slow release, though further studies are necessary for investigating the occurrence of slow dung decomposition in other
forest situations. 相似文献
76.
77.
Chuanxi Cai Haruko Masumiya Noah Weisleder Zui Pan Miyuki Nishi Shinji Komazaki Hiroshi Takeshima Jianjie Ma 《The Journal of biological chemistry》2009,284(5):3314-3322
Membrane recycling and remodeling contribute to multiple cellular
functions, including cell fusion events during myogenesis. We have identified
a tripartite motif (TRIM72) family member protein named MG53 and defined its
role in mediating the dynamic process of membrane fusion and exocytosis in
striated muscle. MG53 is a muscle-specific protein that contains a TRIM motif
at the amino terminus and a SPRY motif at the carboxyl terminus. Live cell
imaging of green fluorescent protein-MG53 fusion construct in cultured
myoblasts showed that although MG53 contains no transmembrane segment it is
tightly associated with intracellular vesicles and sarcolemmal membrane. RNA
interference-mediated knockdown of MG53 expression impeded myoblast
differentiation, whereas overexpression of MG53 enhanced vesicle trafficking
to and budding from sarcolemmal membrane. Co-expression studies indicated that
MG53 activity is regulated by a functional interaction with caveolin-3. Our
data reveal a new function for TRIM family proteins in regulating membrane
trafficking and fusion in striated muscles.When myoblasts exit the cell cycle during myogenesis, dramatic changes in
membrane organization occur as myoblast fusion allows the formation of
multinucleated muscle fibers. In addition to cell fusion events,
differentiation of myotubes involves establishment of specialized membrane
structures (1,
2). The transverse tubular
invagination of sarcolemmal membrane and the intracellular membrane network
known as the sarcoplasmic reticulum are two highly organized membrane
architectures in cardiac and skeletal muscle. Establishment of these intricate
membrane compartments requires extensive remodeling of the immature myoblast
membranes. Dynamic membrane remodeling also contributes to many physiologic
processes in mature muscle, including Ca2+ signaling, trafficking
of glucose transporter (GLUT4), and other membrane internalization events
involving caveolae structures
(3-6).
Although defects in membrane integrity have been linked to various forms of
muscular dystrophy (7,
8), the molecular machinery
regulating these specific membrane recycling and remodeling events in striated
muscle is not well defined.The large tripartite motif
(TRIM)5 family of
proteins is involved in numerous cellular functions in a wide variety of cell
types. Members of this protein family contain signature motifs that include a
RING finger, a zinc binding moiety (B-box), and a
coiled coil structure (RBCC), which invariably comprise
the amino-terminal domain of TRIM family members
(9). The carboxyl-terminal
sequence of TRIM proteins is variable; in some cases a subfamily of TRIM
proteins contains a SPRY domain, a sequence first observed in the ryanodine
receptor Ca2+ channel in the sarcoplasmic reticulum membrane of
excitable cells (10).
Extensive studies have revealed that protein-protein interactions in the
cytosol mediate the defined functions of TRIM proteins. For example, the
ubiquitin E3 ligase enzymatic activity of several TRIM family members requires
the B-box motif (11,
12). Recent studies have also
indicated a role for TRIM proteins in defense against events involving
membrane penetration, such as protection against infection by various viruses,
including human immunodeficiency virus
(13-15).
Although most of the studies concentrate on the cytosolic action of TRIM,
limited reports have investigated the role of TRIM proteins in membrane
signaling or recycling.We have previously established an immunoproteomics approach that allows
definition of novel components involved in myogenesis, Ca2+
signaling, and maintenance of membrane integrity in striated muscle
(16). Using this approach, we
have shown that junctophilin is a structural protein that establishes
functional communication between sarcoplasmic reticulum and transverse tubule
membranes at triad and dyad junctions in striated muscle
(17-19).
Further studies identified mitsugumin 29, a synaptophysin-related protein that
is essential for biogenesis of triad membrane structures and Ca2+
signaling in skeletal muscle
(20,
21). Screening of this
immunoproteomics library led to the recent identification of MG53, a
muscle-specific TRIM family protein
(22). Domain homology analysis
revealed that MG53 contains the prototypical RBCC motifs plus a SPRY domain at
the carboxyl terminus. Genetic knock-out and functional studies reveal that
MG53 nucleates the assembly of the sarcolemmal membrane repair machinery to
restore cellular integrity following acute damage to the muscle fiber
(22).Here we present evidence illustrating that MG53, in contrast to other known
TRIM proteins, can localize to intracellular vesicles and the sarcolemmal
membrane. A functional interaction between MG53 and caveolin-3, another
muscle-specific protein, plays an essential role in regulating the dynamic
process of membrane budding and exocytosis in skeletal muscle. 相似文献
78.
Serum glycoproteins are involved in various biologic activities, such as the removal of exogenous antigens, fibrinolysis, and metal transport. Some of them are also useful markers of inflammation and disease. Although the amount of sialic acid increases following inflammation, little attention has been paid to the presence of linkage-specific epitopes in serum, especially the alpha2,8-linkage. In a previous study, we demonstrated that four components in mouse serum contain alpha2,8-linked disialic acid (diSia), based on immunoreactivity with monoclonal antibody 2-4B, which is specific to N-glycolylneuraminic acid (Neu5Gc)alpha2-->(8Neu5Gc alpha2-->)(n-1), n > or = 2 [Yasukawa et al., (2005) Glycobiology, 15, 827-837]. In this study, we purified three components, 30-, 70-, and 120-kDa gp, and identified them as an immunoglobulin (Ig) light chain, vitronectin, and plasminogen, respectively, using matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy analyses. Modifications of these proteins with alpha2,8-linked diSia were chemically confirmed by fluorometric C7/C9 analyses and mild acid hydrolysates-fluorometric anion-exchange chromatography analyses. We also demonstrated that the IgG, IgM, and IgE light chains are commonly modified with alpha2,8-linked diSia. In addition, both mouse and rat vitronectin contained diSia, and the amount of disialylation in vitronectin dramatically decreased after hepatectomy. These results indicate that a novel diSia modification of serum glycoproteins is biologically important for immunologic events and fibrinolysis. 相似文献
79.
Matsumoto N Kohno T Uchida S Shimizu T Kusumoto H Hirose R Yanada K Kurio W Yamaguchi S Watabe K Fujita T 《Bioorganic & medicinal chemistry》2006,14(12):4182-4192
FTY720 (1) is a novel immunosuppressant (immunomodulator), derived from ISP-I (2: myriocin and thermozymocidin). To clarify the pharmacokinetic properties of 1, antibodies against 1 were prepared and a competitive enzyme immunoassay (EIA) was developed. Two kinds of haptens, 3 and 4, for 1 were synthesized and coupled to ovalbumin (OVA). Rabbits were immunized with 3-OVA or 4-OVA, and corresponding antibodies were obtained. Both antibodies recognized the 2-amino-2-(2-phenylethyl)propane-1,3-diol moiety in 1. Using the anti-3-OVA antibody, a competitive EIA for 1 was developed and evaluated. The range of quantification by the EIA was 0.06-10 ng/mL. The application of the EIA has enabled us to measure the FTY720 concentration in serum after oral administration of 1 (1mg/kg) to rats. 相似文献
80.
Ashikawa Y Fujimoto Z Noguchi H Habe H Omori T Yamane H Nojiri H 《Structure (London, England : 1993)》2006,14(12):1779-1789
Carbazole 1,9a-dioxygenase (CARDO), a member of the Rieske nonheme iron oxygenase system (ROS), consists of a terminal oxygenase (CARDO-O) and electron transfer components (ferredoxin [CARDO-F] and ferredoxin reductase [CARDO-R]). We determined the crystal structures of the nonreduced, reduced, and substrate-bound binary complexes of CARDO-O with its electron donor, CARDO-F, at 1.9, 1.8, and 2.0 A resolutions, respectively. These structures provide the first structure-based interpretation of intercomponent electron transfer between two Rieske [2Fe-2S] clusters of ferredoxin and oxygenase in ROS. Three molecules of CARDO-F bind to the subunit boundary of one CARDO-O trimeric molecule, and specific binding created by electrostatic and hydrophobic interactions with conformational changes suitably aligns the two Rieske clusters for electron transfer. Additionally, conformational changes upon binding carbazole resulted in the closure of a lid over the substrate-binding pocket, thereby seemingly trapping carbazole at the substrate-binding site. 相似文献