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181.
Kuribayashi M Wang J Fujiwara O Doi Y Nabae K Tamano S Ogiso T Asamoto M Shirai T 《Bioelectromagnetics》2005,26(7):578-588
Possible effects of 1439 MHz electromagnetic near field (EMF) exposure on the blood-brain barrier (BBB) were investigated using immature (4 weeks old) and young (10 weeks old) rats, equivalent in age to the time when the BBB development is completed and the young adult, respectively. Alteration of BBB related genes, such as those encoding p-glycoprotein, aquaporin-4, and claudin-5, was assessed at the protein and mRNA levels in the brain after local exposure of the head to EMF at 0, 2, and 6 W/kg specific energy absorption rates (SARs) for 90 min/day for 1 or 2 weeks. Although expression of the 3 genes was clearly decreased after administration of 1,3-dinitrobenzene (DNB) as a positive control, when compared with the control values, there were no pathologically relevant differences with the EMF at any exposure levels at either age. Vascular permeability, monitored with reference to transfer of FITC-dextran, FD20, was not affected by EMF exposure. Thus, these findings suggest that local exposure of the head to 1439 MHz EMF exerts no adverse effects on the BBB in immature and young rats. 相似文献
182.
The genus Clostridium is dominant in human intestinal tracts and plays an important role in human health. We designed species-specific primers to identify 13 species of Clostridium (C. perfringens, C. paraputrificum, C. bifermentans, C. difficile, C. clostridiiforme, C. nexile, C. sphenoides, C. indolis, C. ramosum, C. cocleatum, C. butyricum, C. sordellii, and C. innocuum) easily and rapidly. The PCR annealing temperature was set at a uniform 60 C for application to all strains at the same time. To confirm the specificities of these primers, 85 intestinal bacteria in total, including type strains, reference strains, and isolates were used. Ten primers (including those for C. perfringens to C. cocleatum) indicated high specificities. Although there were some cross-reactions with the other three primers, the target species were distinguishable from other bacteria by the different sizes of PCR products. 相似文献
183.
Nuclei were isolated from somatic embryos of carrot (Daucus carota L.) using a buffer system containing non-ionic detergent. To prepare nuclear matrices, the purified membrane-depleted nuclei were digested with DNase I in combination with RNase A, followed by extraction with 1 M NaCl. The DNA residue in the final insoluble fraction was less than 4% of that in isolated nuclei, and most of the residual nuclei retained their sphericity. Electron microscopy revealed that the nuclear matrix was composed of a distinct peripheral layer, an internal matrix structure and some fibrils; residual nucleoli were observed when exogeneous RNase was not incorporated. The proteins extracted from the nuclei and nuclear subfractions were compared by gel electrophoresis, which showed that the residual fraction contained many minor proteins. To identify proteins showing specific localization at the nuclear periphery, we prepared monoclonal antibodies (MAbs) against an ion-exchange chromatography fraction extracted from carrot nuclear matrices. Immunofluorescence microscopy with one of the MAbs, CML-1, showed exclusive staining of the nuclear periphery. The MAb recognized several spots showing microheterogeneity, with a narrow range of pI and molecular mass upon immunoblotting. A complete set of these spots was shown to be conserved in nuclear matrices. On the other hand, MAb CML-13 appeared to react with the nuclear interior as well as the periphery, recognizing a 96-kDa polypeptide of the nuclear matrix. These proteins were thus demonstrated to lie at the nuclear periphery, and to constitute the nuclear matrices in carrot. The 96-kDa polypeptide is suggested to be similar to the 92-kDa nuclear protein reported by Beven et al. in carrot (Beven et al., 1991, J. Cell Sci. 98, 293–302).Abbreviations DEAE
diethylaminoethyl
- MAb
monoclonal antibody
- NEPHGE
nonequilibrium pH gradient electrophoresis
We wish to thank Ms. Akiko Itoh for excellent technical assistance. This work was supported by a Grant-in-Aid (05640738) from the Ministry of Education of Japan. 相似文献
184.
Summary T-type calcium channels (I
T channels) were studied in cell-attached patch electrode recordings from the ventricular cell membrane of 14-day embryonic chick heart. All experiments were performed in the absence of Ca2+ with Na+ (120mm) as the charge carrier.I
T channels were distinguished from L-type calcium channels (I
L) by their more negative activation and inactivation potential ranges; their smaller unitary slope conductance (26 pS), and their insensitivity to isoproterenol or D600. Inactivation kinetics were voltage dependent. The time constant of inactivation was 37 msec when the membrane potential was depolarized 40 mV from rest (R+40 mV), and 20 msec atR+60 mV. The frequency histogram of channel open times 0 was fit by a single-exponential curve while that of closed times c was biexponeintial.
o
was the same atR+40 mV andR+60 mV whereas
c
was shortened atR+60 mV. The open-state probability (P
o) increased with depolarization: 0.35 atR+40 mV, 0.8 atR+60 mV and 0.88 atR+80 mV. This increase inP
o at depolarized potentials could be accounted for by the decrease in c. 相似文献
185.
186.
The effect of zinc-chelating dipeptides on osteoblastic MC3T3-E1 cells was investigated. As zinc compounds, we used zinc sulfate, AHZ, di(N-acetyl-β-alanyl-l-histidinato)zinc (AAHZ), and di(histidino)zinc (HZ). Cells were cultured for 72 h in the presence of zinc compounds (10−8–10−5M). The effect of AHZ (10−7 and 10−6M) to increase protein and deoxyribonucleic acid (DNA) contents in the cells was the greatest in comparison with those of other zinc compounds. Zinc sulfate and HZ at 10−7M did not have an effect on the cellular protein content. AHZ (10−6M) had a potent effect on cell proliferation, although zinc sulfate (10−6M) had no effect. β-Alanyl-l-histidine (10−6 and 10−5M) did not have an appreciable effect on the cells. Those effects of AHZ (10−6M) on osteoblastic cells were completely abolished by the presence of cycloheximide (10−6M). AHZ (10−8–10−5M) directly activated [3H]leucyl-tRNA synthetase in the cell homogenate, whereas the effect of zinc sulfate was seen at 10−6 and 10−5M. The present study suggests that the chemical form of zinc-chelating β-alanyl-l-histidine (AHZ) can reveal a potent anabolic effect on osteoblastic cells, and that AHZ directly stimulates protein synthesis. 相似文献
187.
Takeuchi K Takahashi H Kawano S Shimada I 《The Journal of biological chemistry》2007,282(20):15179-15186
Gating of ion channels is strictly regulated by physiological conditions as well as intra/extracellular ligands. To understand the underlying structures mediating ion channel gating, we investigated the pH-dependent gating of the K(+) channel KcsA under near-physiological conditions, using solution-state NMR. In a series of (1)H(15)N-TROSY HSQC (transverse relaxation optimized spectroscopy-heteronuclear single quantum coherence) spectra measured at various pH values, significant chemical shift changes were detected between pH 3.9 and 5.2, reflecting a conformational rearrangement associated with the gating. The pH-dependent chemical shift changes were mainly observed for the resonances from the residues near the intracellular helix bundle, which has been considered to form the primary gate in the K(+) channel, as well as the intracellular extension of the inner helix. The substitution of His-25 by Ala abolished this pH-dependent conformational rearrangement, indicating that the residue serves as a "pH-sensor" for the channel. Although the electrophysiological open probability of KcsA is less than 10%, the conformations of the intracellular helix bundle between the acidic and neutral conditions seem to be remarkably different. This supports the recently proposed "dual gating" properties of the K(+) channel, in which the activation-coupled inactivation at the selectivity filter determines the channel open probability of the channel. Indeed, a pH-dependent chemical shift change was also observed for the signal from the Trp-67 indole, which is involved in a hydrogen bond network related to the activation-coupled inactivation. The slow kinetic parameter obtained for the intracellular bundle seems to fit better into the time scale for burst duration than very fast fluctuations within a burst period, indicating the existence of another gating element with faster kinetic properties. 相似文献
188.
Matsuura T Endo S Iwamoto R Takahashi H Ichinose M 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,147(4):920-927
The chemotactic behavior of the nematode Caenorhabditis elegans to chemical attractants, water-soluble sodium acetate and odorant diacetyl, was investigated using nematodes at various developmental stages to examine the effects of postembryonic development on chemotactic response and spontaneous locomotion. The chemotactic responses to attractants increased as development progressed, and the largest responses to either 1.0 M sodium acetate or 0.1% diacetyl were seen at the young adult (YA) or day adult (A1) stage, respectively. Responses to the chemicals declined thereafter in-line with increasing age. The chemotaxis indices for attractants correlated with activity of spontaneous locomotion (p<0.01), suggesting that a change in spontaneous locomotion is one of the factors involved with the change in chemotactic responses during development. We also investigated the effect of aging on attractant choice by the simultaneous presentation of 0.6 M sodium acetate and 0.1% diacetyl. In the presence of both attractants, the fraction of larval animals at the sodium acetate location was greater than that at the diacetyl location (p<0.05). The fractions of YA animals that gathered at either location were almost identical, whereas the fraction of adult animals at the diacetyl location was greater than that at the sodium acetate location (p<0.05). The patterns of attractant choice of the long-lived daf-2 mutants and short lifespan mev-1 mutants showed the same tendency as those of wild type nematodes in the presence of both attractants. These results suggest that a change in the neuronal mechanisms controlling attractant choice and preference occurs during developmental progression. 相似文献
189.
Huang J Aki T Yokochi T Nakahara T Honda D Kawamoto S Shigeta S Ono K Suzuki O 《Marine biotechnology (New York, N.Y.)》2003,5(5):450-457
Seven strains of marine microbes producing a significant amount of docosahexaenoic acid (DHA;
C22:6, n-3) were screened from seawater collected in coastal areas of Japan and Fiji. They accumulate their
respective intermediate fatty acids in addition to DHA. There are 5 kinds of polyunsaturated fatty acid (PUFA)
profiles which can be described as (1) DHA/docosapentaenoic acid (DPA; C22:5, n-6), (2) DHA/DPA/eicosapentaenoic
acid (EPA; C20:5, n-3), (3) DHA/EPA, (4) DHA/DPA/EPA/arachidonic acid (AA; C20:4, n-6),
and (5) DHA/DPA/EPA/AA/docosatetraenoic acid (C22:4, n-6). These isolates are proved to be new thraustochytrids
by their specific insertion sequences in the 18S rRNA genes. The phylogenetic tree constructed by
molecular analysis of 18S rRNA genes from the isolates and typical thraustochytrids shows that strains with the
same PUFA profile form each monophyletic cluster. These results suggest that the C20-22 PUFA profile may be
applicable as an effective characteristic for grouping thraustochytrids. 相似文献
190.
Adenovirus vector expressing keratinocyte growth factor using CAG promoter impairs pulmonary function of mice with elastase‐induced emphysema 下载免费PDF全文
Hiroshi Oki Takuya Yazawa Yasuko Baba Yumi Kanegae Hanako Sato Seiko Sakamoto Takahisa Goto Izumu Saito Kiyoyasu Kurahashi 《Microbiology and immunology》2017,61(7):264-271