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31.
Fujii R Shimonaka S Uchida N Gardiner AT Cogdell RJ Sugisaki M Hashimoto H 《Photosynthesis research》2008,95(2-3):327-337
Typical purple bacterial photosynthetic units consist of supra-molecular arrays of peripheral (LH2) and core (LH1-RC) antenna
complexes. Recent atomic force microscopy pictures of photosynthetic units in intact membranes have revealed that the architecture
of these units is variable (Scheuring et al. (2005) Biochim Bhiophys Acta 1712:109–127). In this study, we describe methods for the construction of heterologous photosynthetic
units in lipid-bilayers from mixtures of purified LH2 (from Rhodopseudomonas acidophila) and LH1-RC (from Rhodopseudomonas viridis) core complexes. The architecture of these reconstituted photosynthetic units can be varied by controlling ratio of added
LH2 to core complexes. The arrangement of the complexes was visualized by electron-microscopy in combination with Fourier
analysis. The regular trigonal array of the core complexes seen in the native photosynthetic membrane could be regenerated
in the reconstituted membranes by temperature cycling. In the presence of added LH2 complexes, this trigonal symmetry was
replaced with orthorhombic symmetry. The small lattice lengths for the latter suggest that the constituent unit of the orthorhombic
lattice is the LH2. Fluorescence and fluorescence-excitation spectroscopy was applied to the set of the reconstituted membranes
prepared with various proportions of LH2 to core complexes. Remarkably, even though the LH2 complexes contain bacteriochlorophyll
a, and the core complexes contain bacteriochlorophyll b, it was possible to demonstrate energy transfer from LH2 to the core complexes. These experiments provide a first step along
the path toward investigating how changing the architecture of purple bacterial photosynthetic units affects the overall efficiency
of light-harvesting. 相似文献
32.
Cleavage of a DNA-RNA-DNA/DNA chimeric substrate containing a single ribonucleotide at the DNA-RNA junction with prokaryotic RNases HII 总被引:1,自引:0,他引:1
We have analyzed the cleavage specificities of various prokaryotic Type 2 ribonucleases H (RNases H) on chimeric DNA-RNA-DNA/DNA substrates containing one to four ribonucleotides. RNases HII from Bacillus subtilis and Thermococcus kodakaraensis cleaved all of these substrates to produce a DNA segment with a 5'-monoribonucleotide. Consequently, these enzymes cleaved even the chimeric substrate containing a single ribonucleotide at the DNA-RNA junction (5'-side of the single ribonucleotide). In contrast, Escherichia coli RNase HI and B. subtilis RNase HIII did not cleave the chimeric substrate containing a single ribonucleotide. These results suggest that bacterial and archaeal RNases HII are involved in excision of a single ribonucleotide misincorporated into DNA. 相似文献
33.
Mitsuru Kuwamura Yosuke Ando Akiko Takada Toshiko Kanehara Jyoji Yamate Takao Kotani Shigehito Takeshita Miyuki Kanbori Kazuhiro Kitada Tadao Serikawa 《Experimental Animals》2004,53(1):21-26
In this paper, we executed genome mapping and comparative mapping analyses for cvd and hob, autosomal recessive mutations with cerebellar vermis defect and cerebellar dysplasia in the rat. For the linkage analysis, we produced three sets of backcross progeny, (ACI x CVD)F(1) and (F344 x CVD)F(1) females crossed to a cvd homozygous male rat, and (HOB x WKY)F(1) males crossed to hob homozygous female rats. Analysis of the segregation patterns of simple sequence length polymorphism (SSLP) markers scanning the whole rat genome allowed the mapping of these autosomal recessive mutations to rat Chromosome (Chr) 2. The most likely gene order is D2Mgh12 - D2Rat86 - D2Mit15 - D2Rat185 - cvd - D2Rat66 - D2Mgh13, and D2Mit18 - Fga -D2Mit14 - D2Rat16 - hob - D2Mgh13. Crossing test between a proven cvd heterozygous and a hob heterozygous rats demonstrated their allelism. Furthermore, comparative mapping indicated the cvd locus corresponds to mouse chromosome 3 and a strong candidate gene Unc5h3, a causative gene for the rostral cerebellar malformation mouse, was implicated. 相似文献
34.
Yamakawa I Kojima H Terashima T Katagi M Oi J Urabe H Sanada M Kawai H Chan L Yasuda H Maegawa H Kimura H 《American journal of physiology. Endocrinology and metabolism》2011,301(5):E844-E852
Tumor necrosis factor (TNF)-α is a potent proinflammatory cytokine involved in the pathogenesis of diabetic neuropathy. We inactivated TNF-α to determine if it is a valid therapeutic target for the treatment of diabetic neuropathy. We effected the inactivation in diabetic neuropathy using two approaches: by genetic inactivation of TNF-α (TNF-α(-/-) mice) or by neutralization of TNF-α protein using the monoclonal antibody infliximab. We induced diabetes using streptozotocin in wild-type and TNF-α(-/-) mice. We measured serum TNF-α concentration and the level of TNF-α mRNA in the dorsal root ganglion (DRG) and evaluated nerve function by a combination of motor (MNCV) and sensory (SNCV) nerve conduction velocities and tail flick test, as well as cytological analysis of intraepidermal nerve fiber density (IENFD) and immunostaining of DRG for NF-κB p65 serine-276 phosphorylated and cleaved caspase-3. Compared with nondiabetic mice, TNF-α(+/+) diabetic mice displayed significant impairments of MNCV, SNCV, tail flick test, and IENFD as well as increased expression of NF-κB p65 and cleaved caspase-3 in their DRG. In contrast, although nondiabetic TNF-α(-/-) mice showed mild abnormalities of IENFD under basal conditions, diabetic TNF-α(-/-) mice showed no evidence of abnormal nerve function tests compared with nondiabetic mice. A single injection of infliximab in diabetic TNF-α(+/+) mice led to suppression of the increased serum TNF-α and amelioration of the electrophysiological and biochemical deficits for at least 4 wk. Moreover, the increased TNF-α mRNA expression in diabetic DRG was also attenuated by infliximab, suggesting infliximab's effects may involve the local suppression of TNF-α. Infliximab, an agent currently in clinical use, is effective in targeting TNF-α action and expression and amelioration of diabetic neuropathy in mice. 相似文献
35.
Shoji Hayashi Alexandra Houssaye Yasuhisa Nakajima Kentaro Chiba Tatsuro Ando Hiroshi Sawamura Norihisa Inuzuka Naotomo Kaneko Tomohiro Osaki 《PloS one》2013,8(4)
Background
The paleoecology of desmostylians has been discussed controversially with a general consensus that desmostylians were aquatic or semi-aquatic to some extent. Bone microanatomy can be used as a powerful tool to infer habitat preference of extinct animals. However, bone microanatomical studies of desmostylians are extremely scarce.Methodology/Principal Findings
We analyzed the histology and microanatomy of several desmostylians using thin-sections and CT scans of ribs, humeri, femora and vertebrae. Comparisons with extant mammals allowed us to better understand the mode of life and evolutionary history of these taxa. Desmostylian ribs and long bones generally lack a medullary cavity. This trait has been interpreted as an aquatic adaptation among amniotes. Behemotops and Paleoparadoxia show osteosclerosis (i.e. increase in bone compactness), and Ashoroa pachyosteosclerosis (i.e. combined increase in bone volume and compactness). Conversely, Desmostylus differs from these desmostylians in displaying an osteoporotic-like pattern.Conclusions/Significance
In living taxa, bone mass increase provides hydrostatic buoyancy and body trim control suitable for poorly efficient swimmers, while wholly spongy bones are associated with hydrodynamic buoyancy control in active swimmers. Our study suggests that all desmostylians had achieved an essentially, if not exclusively, aquatic lifestyle. Behemotops, Paleoparadoxia and Ashoroa are interpreted as shallow water swimmers, either hovering slowly at a preferred depth, or walking on the bottom, and Desmostylus as a more active swimmer with a peculiar habitat and feeding strategy within Desmostylia. Therefore, desmostylians are, with cetaceans, the second mammal group showing a shift from bone mass increase to a spongy inner organization of bones in their evolutionary history. 相似文献36.
Shinichi Kitamura Takashi Hirano Kenichi Takeo Mitsuru Mimura Kanji Kajiwara Bjrn T. Stokke Tsutomu Harada 《International journal of biological macromolecules》1994,16(6)
The conformation and dilute solution properties of (2→1)-β-d-fructan in aqueous solution were studied by gel permeation chromatography, low-angle laser light-scattering photometry, viscometry, small-angle X-ray scattering and electron microscopy. Fractions covering a broad range of weight-average molecular weights (Mw) from 1.49 × 104 to 5.29 × 106 were obtained from a native sample by ultrasonic degradation and fractional precipitation. For Mw < 4 × 104, the intrinsic viscosity [η] varies with Mw0.71, indicating that the fructan chain behaves as a random coil expanded by an excluded-volume effect in this molecular weight region. For Mw > 105, [η] exhibits an unusually weak dependence on Mw and finally becomes almost independent of molecular weight. This behaviour is interpreted in terms of a globular conformation of the high-molecular-weight fructan molecules. Small-angle X-ray-scattering measurements and electron microscopic observations support this interpretation of the values of [η] observed. 相似文献
37.
Noritsugu Yabe Yutaka Matsuya Isao Yamane Mitsuru Takada 《In vitro cellular & developmental biology. Plant》1986,22(7):363-368
Summary A newly developed, serum-free medium (NYSF-404) selects for antibody-producing hybridomas after fusion of antigen-sensitized
mouse spleen cells with myeloma cell lines P3-X63-Ag8-U1 (P3-U1), P3-X63-Ag8-6.5.3 (Ag8.653), or P3-NSI/1-Ag4-1 (NS-1). Without
the need for hypoxanthine-aminopterinthymidine (HAT) selection of hybrid cells, frequency of hybridoma formation in medium
NYSF-404 is higher (twice) than that in serum- and HAT-containing medium. Colonies developed upon limiting dilution in the
presence of the mortal parent myeloma cells in medium NYSF-404 and pure culture of antibody-secreting cells could be subsequently
established. The results suggest that fusions can be done in serum-free medium and that the clonal growth of hybridomas is
dependent on factors produced by parent myeloma cells under serum-free culture conditions. Such factors seem deficient in
serum- and HAT-containing medium or are masked by serum. 相似文献
38.
Yasuro Yoshimura Takayuki Kawano Mitsuru Kuroi Masaaki Morishita Masahiko Mori Kensaku Kawakatsu 《Histochemistry and cell biology》1970,22(4):337-346
Summary Analysis of lactate and malate dehydrogenase zymograms of rodent salivary glands showed species and organ specific patterns.Lactate dehydrogenase isoenzyme patterns occupied the middle positions in relation to those of skeletal and heart muscle. Activities of the major salivary glands were in the order submaxillary gland>parotid>sublingual gland. Zymogram of the mouse and rat showed LDH4 and LDH5 high activity patterns, while that of the rabbit was the fast moving active one. Hamster salivary gland exhibited a neutral type of the former and the latter.Malate dehydrogenase isoenzyme exhibited very similar patterns for the mouse, rat and hamster. Malate dehydrogenase zymogram of rabbit showed 3 active bands, which was different from the other rodents. 相似文献
39.
Tanaka M Sagawa S Hoshi J Shimoma F Yasue K Ubukata M Ikemoto T Hase Y Takahashi M Sasase T Ueda N Matsushita M Inaba T 《Bioorganic & medicinal chemistry》2006,14(17):5781-5794
Conformationally restricted 3-anilino-4-(3-indolyl)maleimide derivatives were designed and synthesized aiming at discovery of novel protein kinase Cbeta (PKCbeta)-selective inhibitors possessing oral bioavailability. Among them, compounds having a fused five-membered ring at the indole 1,2-position inhibited PKCbeta2 with IC50 of nM-order and showed good oral bioavailability. One of the most potent compounds was found to be PKCbeta-selective over other 6 isozymes and exhibited ameliorative effects in a rat diabetic retinopathy model via oral route. 相似文献
40.