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251.
Loss of collapsin response mediator protein 4 suppresses dopaminergic neuron death in an 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine‐induced mouse model of Parkinson's disease 下载免费PDF全文
Aine Tonouchi Jun Nagai Kentaro Togashi Yoshio Goshima Toshio Ohshima 《Journal of neurochemistry》2016,137(5):795-805
252.
Hoyeun Kim Masami Yokota Hirai Hiroaki Hayashi Mitsuo Chino Satoshi Naito Toru Fujiwara 《Planta》1999,209(3):282-289
The composition of seed storage proteins is regulated by sulfur and nitrogen supplies. Under conditions of a low sulfur-to-nitrogen
ratio, accumulation of the β-subunit of β-conglycinin, a sulfur-poor seed storage protein of soybean (Glycine max [L.] Merr.), is elevated, whereas that of glycinin, a sulfur-rich storage protein, is reduced. Using transgenic Arabidopsis thaliana [L.] Heynh., it was found that the promoter from the gene encoding the β-subunit of β-conglycinin up-regulates gene expression
under sulfur deficiency and down-regulates gene expression under nitrogen deficiency. To obtain an insight into the metabolic
control of this regulation, the concentrations of metabolites related to the sulfur assimilation pathway were determined.
Among the metabolites, O-acetyl-l-serine (OAS), one of the precursors of cysteine biosynthesis, accumulated to higher levels under low-sulfur and high-nitrogen
conditions in siliques of transgenic A. thaliana. The pattern of OAS accumulation in response to various levels of sulfur and nitrogen was similar to that of gene expression
driven by the β-subunit promoter. Elevated levels of OAS accumulation were also observed in soybean cotyledons cultured under
sulfur deficiency. Moreover, OAS applied to in-vitro cultures of immature soybean cotyledons under normal sulfate conditions
resulted in a high accumulation of the β-subunit mRNA and protein, whereas the accumulation of glycinin was reduced. These
changes were very similar to the responses observed under conditions of sulfur deficiency. Our results suggest that the level
of free OAS mediates sulfur- and nitrogen-regulation of soybean seed storage-protein composition.
Received: 6 February 1999 / Accepted: 16 March 1999 相似文献
253.
T. Togashi Taizo Motomura Terunobu Ichimura Paul Alan Cox 《Sexual plant reproduction》1999,12(3):158-163
The role of phototactic behavior of gametes was tested experimentally in the slightly anisogamous marine green alga Monostroma angicava Kjellman, and the effect of phototaxis on mating efficiency was discovered. Both male and female gametes showed positive
phototaxis in response to a white light source. In contrast, they did not respond to a red light source. Their swimming velocity
did not differ between these two illuminating light sources. It was, therefore, suggested that the search ability of the gamete
itself might not vary between phototactic and non-phototactic conditions. The number of zygotes formed during the mating process
may be expressed as the product of the number of encounters between male and female gametes and the fraction of encounters
that result in sexual fusion. In this study, with high densities of male and female gametes mixed in test tubes, almost all
minor (fewer in number) gametes fused sexually within 10 min. After dilution of the gamete suspensions by half, mating efficiency
in test tubes illuminated by white light from above was higher than that in dark controls. This suggests that male and female
gametes gathered at the water surface through their positive phototaxis, thus increasing the rate of encounters. Mating efficiency
also decreased if the test tubes were illuminated from above by white light and also shaken. Since negative phototaxis is
clearly shown in planozygotes, we suggest that positive phototaxis of male and female gametes in M. angicava is an adaptive trait for increasing the rate of gametic encounters rather than for the dispersal of zygotes as previously
reported for zoospores of some marine algae.
Received: 12 February 1999 / Revision accepted: 24 May 1999 相似文献
254.
The present study was undertaken to assess the effects of sodium nitroprusside (SNP) and diethylamine NO(C2H5)2N[N(O)NO]−Na+ (DEA/NO), NO donors, on an acetylcholine (ACh)-induced Cl− current in identified Onchidium neurons using voltage-clamp and pressure ejection techniques. Bath-applied SNP (10 μM) and DEA/NO (5–10 μM) reduced the ACh-induced Cl− current in the neurons without affecting the resting membrane conductance and holding current. The suppressing effects of NO donors were concentration-dependent and completely reversible. Pretreatment with 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (1 μM), a specific inhibitor of NO-stimulated guanylate cyclase, and hemoglobin (50 μM), a nitric oxide scavenger, decreased the SNP-induced inhibition of the ACh-induced current. Intracellular injection of guanosine 3′,5′-cyclic monophosphate (cGMP) or bath-application of 3-isobutyl-1-methylxanthine (50 μM), a non-specific phosphodiesterase inhibitor, inhibited the ACh-induced current, mimicking the effect of NO donors. These results suggest that SNP and DEA/NO inhibit the ACh-induced Cl− current and that this effect is mediated by an increase in intracellular cGMP. © 1998 John Wiley & Sons, Inc. J Neurobiol 35: 388–394, 1998 相似文献
255.
A novel regulatory mechanism of myosin light chain phosphorylation via binding of 14-3-3 to myosin phosphatase 下载免费PDF全文
Myosin II phosphorylation-dependent cell motile events are regulated by myosin light-chain (MLC) kinase and MLC phosphatase (MLCP). Recent studies have revealed myosin phosphatase targeting subunit (MYPT1), a myosin-binding subunit of MLCP, plays a critical role in MLCP regulation. Here we report the new regulatory mechanism of MLCP via the interaction between 14-3-3 and MYPT1. The binding of 14-3-3beta to MYPT1 diminished the direct binding between MYPT1 and myosin II, and 14-3-3beta overexpression abolished MYPT1 localization at stress fiber. Furthermore, 14-3-3beta inhibited MLCP holoenzyme activity via the interaction with MYPT1. Consistently, 14-3-3beta overexpression increased myosin II phosphorylation in cells. We found that MYPT1 phosphorylation at Ser472 was critical for the binding to 14-3-3. Epidermal growth factor (EGF) stimulation increased both Ser472 phosphorylation and the binding of MYPT1-14-3-3. Rho-kinase inhibitor inhibited the EGF-induced Ser472 phosphorylation and the binding of MYPT1-14-3-3. Rho-kinase specific siRNA also decreased EGF-induced Ser472 phosphorylation correlated with the decrease in MLC phosphorylation. The present study revealed a new RhoA/Rho-kinase-dependent regulatory mechanism of myosin II phosphorylation by 14-3-3 that dissociates MLCP from myosin II and attenuates MLCP activity. 相似文献
256.
In this study, we surveyed the uranium (U) load in stream water within a humid forest in Japan, and clarified the fact that
changes in U load depended on the amount of sediment accumulated behind dams constructed along the stream. To elucidate the
relationship between U and the accumulated sediments, we conducted U sorption experiments in the laboratory using stream water
and sampled sediments. The chemistry of the stream water was analyzed in the field for pH, electrical conductivity (EC), and
temperature, as well as laboratory analyses via inductively coupled plasma mass spectrometry (ICP-MS). We determined the amount
of organic material, amorphous material, and total U contents in the sediments. Following the sorption experiments, we analyzed
the pH and U concentrations in experimental solutions and determined the distribution coefficients of U for the sediments.
The logarithm value of the distribution coefficients of U for amorphous material shows a positive correlation with pH, while
the logarithm value of the distribution coefficients of U for organic material is independent of pH (4.7–6.9). Although the
logarithm value of the distribution coefficient of U for amorphous material was 0.1–0.5 units larger than the value for organic
material, U was effectively removed from the stream water by sorption onto organic material (humic substances and decomposing
leaves), because the amount of organic material exceeded that of amorphous material. 相似文献
257.
Otsuki S Taniguchi N Grogan SP D'Lima D Kinoshita M Lotz M 《Arthritis research & therapy》2008,10(3):R61
Introduction
Changes in sulfation of cartilage glycosaminoglycans as mediated by sulfatases can regulate growth factor signaling. The aim of this study was to analyze expression patterns of recently identified extracellular sulfatases Sulf-1 and Sulf-2 in articular cartilage and chondrocytes. 相似文献258.
Sumino M Ohkubo A Taguchi H Seio K Sekine M 《Bioorganic & medicinal chemistry letters》2008,18(1):274-277
5-Carboxy-2'-deoxycytidine (dC(COO-)) was synthesized as an anion-carrier to seek a new possibility of modified oligodeoxynucleotides capable of stabilization of duplexes and triplexes. The base pairing properties of this compound were evaluated by use of ab initio calculations. These calculations suggest that the Hoogsteen-type base pair of dC(COO-)-G is less stable than that of the canonical C+-G pair and the Watson-Crick-type base pair of dC(COO-)-G is slightly more stable than the natural G-C base pair. The modified cytosine base showed a basicity similar to that of cytosine (pKa 4.2). It turned out that oligodeoxynucleotides 13mer and 14mer incorporating dC(COO-) could form duplexes with the complementary DNA oligomer, which were more stable than the unmodified duplex. In contrast, it formed a relatively unstable triplex with the target ds DNA. 相似文献
259.
Seio K Mizuta M Tasaki K Tamaki K Ohkubo A Sekine M 《Bioorganic & medicinal chemistry》2008,16(17):8287-8293
We report the synthesis and properties of oligonucleotides incorporating N(6)-[N-(pyren-1-ylmethyl)carbamoyl]-deoxyadenosine (dA(pymcm)). We designed the ODN which incorporated two consecutive dA(pymcm) residues. It was revealed that on hybridization with the target DNA and RNA oligomers, the fluorescence spectra of ODNs having two consecutive dA(pymcm) molecules near the 5'-terminal position can change from the pyrene monomer emission to the excimer, depending on the chain length of the target DNA and RNA. These results indicated that dA(pymcm)-modified ODNs can be used as interesting hybridization sensors that are sensitive to the size of the target strand. 相似文献
260.
Xiao G Miyazato A Inden K Nakamura K Shiratori K Nakagawa K Miyazawa T Suzuki K Kaku M Kawakami K 《Microbiology and immunology》2008,52(3):171-179
Cryptococcus neoformans is eradicated by macrophages via production of NO. Unmethylated CpG-ODN protect mice from infection with this fungal pathogen by inducing IFN-gamma. The present study was designed to elucidate the effect of C. neoformans on the synthesis of NO by alveolar macrophages. For this purpose, MH-S, an alveolar macrophage cell line, was stimulated with CpG-ODN in the presence of IFN-gamma. A highly virulent strain of C. neoformans with thick capsule suppressed the production of NO. Capsular polysaccharides were not essential for this suppression, because there was no difference between acapsular mutant (Cap67) and its parent strain. Physical or close interaction of Cap67 with MH-S was necessary, as shown by the loss of such effect when direct contact was interfered by nitrocellulose membrane. Similar effects were observed by disrupted as well as intact Cap67. Whereas the inhibitory effect of intact Cap67 was completely abrogated by heat treatment, disrupted Cap67 did not receive such influence. Finally, disrupted Cap67 did not show any inhibitory effect on the TLR9-mediated activation of NF-kappaB in a luciferase reporter assay with HEK293T cells, although the TLR4-mediated activation was suppressed. These results revealed that C. neoformans suppressed the synthesis of NO by CpG-ODN and IFN-gamma-stimulated macrophages in a fashion independent of capsular polysaccharides, although the precise mechanism remains to be elucidated. 相似文献