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31.
Mature chick optic tecta consist of 16 laminae and receive retinal fiber projections in a precise retinotopic manner. Retinal axons arborize in laminae a-f of the SGFS, but do not cross the border between lamina f and g. In order to elucidate molecular mechanisms of tectal laminar formation, we first looked at the migration of tectal postmitotic cells. We found that the migration pattern of postmitotic cells changes around E5 and that late migratory cells intervened laminae that were formed by early migratory cells. The coincident appearance of Grg4 expression in the tectal ventricular layer and the change in migration pattern suggested an important role for Grg4. Clonal misexpression of Grg4 resulted in cells migrating to laminae h-j of the SGFS. Massive misexpression of Grg4 resulted in disruption of laminae that were formed by early migratory cells, in particular lamina g of the SGFS. Application of Grg4 morpholino antisense oligonucleotide or the misexpression of a dominant-negative form of Grg4 exerted the opposite effect. We concluded that Grg4 may direct tectal postmitotic cells to follow a late migratory pathway. 相似文献
32.
Dr. Matthew D. Collins Reiner M. Kroppenstedt Jin Támaoka Kazuo Komagata Takeshi Kinoshita 《Current microbiology》1988,17(5):275-279
The structures of the tetrahydrogenated menaquinones fromActinomadura angiospora, Faenia rectivirgula, andSaccharothrix australiensis were determined by mass spectrometry and proton nuclear magnetic resonance spectrometry. The positions of saturation of the tetrahydrogenated menaquinones fromFaenia rectivirgula andSaccharothrix australiensis were units II plus III (counting from the ring system), whereas that ofActinomadura angiospora had units III and VIII hydrogenated. The tetrahydrogenated menaquinones fromFaenia rectivirgula andSaccharothrix australiensis are similar to those characterized from other Gram-positive taxa to date, whereas that fromActinomadura angiospora represents a hitherto unknown isomer. 相似文献
33.
Wenwen Li Kaku Goto Yasuo Matsubara Sayaka Ito Ryosuke Muroyama Qiang Li Naoya Kato 《PloS one》2015,10(5)
Objectives
Mutations in hepatitis B virus (HBV) X region (HBx) play important roles in hepatocarcinogenesis while the results remain controversial. We sought to clarify potential hepatocellular carcinoma (HCC)-characteristic mutations in HBx from HBV genotype C-infected patients and the distribution of those mutations in different disease phases and genotypes.Methods
HBx sequences downloaded from an online global HBV database were screened and then classified into Non-HCC or HCC group by diagnosis information. Patients'' data of patient age, gender, country or area, and viral genotype were also extracted. Logistic regression was performed to evaluate the effects of mutations on HCC risk.Results
1) Full length HBx sequences (HCC: 161; Non-HCC: 954) originated from 1115 human sera across 29 countries/areas were extracted from the downloaded 5956 HBx sequences. Genotype C occupied 40.6% of Non-HCC (387/954) and 89.4% of HCC (144/161). 2) Sixteen nucleotide positions showed significantly different distributions between genotype C HCC and Non-HCC groups. 3) Logistic regression showed that mutations A1383C (OR: 2.32, 95% CI: 1.34-4.01), R1479C/T (OR: 1.96, 95% CI: 1.05-3.64; OR: 5.15, 95% CI: 2.53-10.48), C1485T (OR: 2.40, 95% CI: 1.41-4.08), C1631T (OR: 4.09, 95% CI: 1.41-11.85), C1653T (OR: 2.58, 95% CI: 1.59-4.19), G1719T (OR: 2.11, 95% CI: 1.19-3.73), and T1800C (OR: 23.59, 95% CI: 2.25-247.65) were independent risk factors for genotype C HBV-related HCC, presenting different trends among individual disease phases. 4) Several genotype C HCC risk mutations pre-existed, even as major types, in early disease phases with other genotypes.Conclusions
Mutations associated with HCC risk were mainly located in HBx transactivation domain, viral promoter, protein/miRNA binding sites, and the area for immune epitopes. Furthermore, the signatures of these mutations were unique to disease phases leading to HCC, suggesting molecular counteractions between the virus and host during hepatocarcinogenesis. 相似文献34.
Akira Yano Sayaka Kikuchi Yoshihisa Yamashita Yuichi Sakamoto Yuko Nakagawa Yasuo Yoshida 《Applied microbiology and biotechnology》2010,86(2):615-623
Mushrooms contain large quantities of α-glucans. Shiitake (Lentinula edodes), Japan’s most popular edible mushroom, has been reported to contain about 6% (weight/dried weight) of α-(1,3)-glucan. This
glucan is one of the major components of oral biofilm formed by the cariogenic bacteria Streptococcus mutans and Streptococcus sobrinus. We found that extracts from shiitake and other edible mushrooms could reduce preformed biofilms of S. mutans and S. sobrinus in the presence of dextranase. We also investigated the α-glucanase activities of shiitake mushroom extracts and their effects
on biofilm formation. The extracts possessed α-glucanase activity and degraded water-insoluble glucans from mutans streptococci.
The extracts strongly inhibited the sucrose-dependent formation of biofilms by S. mutans and S. sobrinus in the presence of dextranase. Our results suggest that some components of mushrooms, including α-glucanases, might inhibit
the sucrose-induced formation of oral biofilms. 相似文献
35.
36.
Characterization of a broadly reactive monoclonal antibody against norovirus genogroups I and II: recognition of a novel conformational epitope 下载免费PDF全文
Shiota T Okame M Takanashi S Khamrin P Takagi M Satou K Masuoka Y Yagyu F Shimizu Y Kohno H Mizuguchi M Okitsu S Ushijima H 《Journal of virology》2007,81(22):12298-12306
Norovirus, which belongs to the family Caliciviridae, is one of the major causes of nonbacterial acute gastroenteritis in the world. The main human noroviruses are of genogroup I (GI) and genogroup II (GII), which were subdivided further into at least 15 and 18 genotypes (GI/1 to GI/15 and GII/1 to GII/18), respectively. The development of immunological diagnosis for norovirus had been hindered by the antigen specificity of the polyclonal antibody. Therefore, several laboratories have produced broadly reactive monoclonal antibodies, which recognize the linear GI and GII cross-reactive epitopes or the conformational GI-specific epitope. In this study, we characterized the novel monoclonal antibody 14-1 (MAb14-1) for further development of the rapid immunochromatography test. Our results demonstrated that MAb14-1 could recognize 15 recombinant virus-like particles (GI/1, 4, 8, and 11 and GII/1 to 7 and 12 to 15) and showed weak affinity to the virus-like particle of GI/3. This recognition range is the broadest of the existing monoclonal antibodies. The epitope for MAb14-1 was identified by fragment, sequence, structural, and mutational analyses. Both terminal antigenic regions (amino acid positions 418 to 426 and 526 to 534) on the C-terminal P1 domain formed the conformational epitope and were in the proximity of the insertion region (positions 427 to 525). These regions contained six amino acids responsible for antigenicity that were conserved among genogroup(s), genus, and Caliciviridae. This epitope mapping explained the broad reactivity and different titers among GI and GII. To our knowledge, we are the first group to identify the GI and GII cross-reactive monoclonal antibody, which recognizes the novel conformational epitope. From these data, MAb14-1 could be used further to develop immunochromatography. 相似文献
37.
Sayaka Hori Hideaki Takeuchi Takeo Kubo 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(8):825-833
We previously studied a conditioning paradigm to associate the proboscis extension reflex (PER) with monochromatic light (conditioned
stimulus; CS) in harnessed honeybees. Here, we established a novel conditioning paradigm to associate the PER with a motion
cue generated using graphics interchange format (GIF) animations with a speed of 12 mm/s speed and a frame rate of 25 Hz as
the CS, which were projected onto a screen consisting of a translucent circular cone that largely covered the visual field
of the harnessed bee using two liquid crystal projectors. The acquisition rate reached a plateau at approximately 40% after
seven trials, indicating that the bees were successfully conditioned with the motion cue. We demonstrated four properties
of the conditioning paradigm. First, the acquisition rate was enhanced by antennae deprivation, suggesting that sensory input
from the antennae interferes with the visual associative learning. Second, bees conditioned with a backward-direction motion
cue did not respond to the forward-direction, suggesting that bees can discriminate the two directions in this paradigm. Third,
the bees can retain memory for motion cue direction for 48 h. Finally, the acquisition rate did not differ significantly between
foragers and nurse bees.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
38.
RNA interference (RNAi) has been used to suppress gene expression in various eukaryotic organisms. In plants, RNAi can be
induced by introduction of an RNAi vector that transcribes a self-complementary hairpin RNA. Most basic RNAi constructs have
an inverted repeat interrupted with a spacer sequence. To test silencing capability of RNAi constructs, we developed an in
vivo assay that is based on the RNAi-mediated changes of the α-linolenic acid content in hairy roots. A tobacco endoplasmic
reticulum ω-3 fatty acid desaturase (NtFAD3) is the main enzyme for production of α-linolenic acid of root membrane lipids.
Tobacco hairy roots transformed with the RNAi vectors against the NtFAD3 gene showed a decrease in α-linolenic acid content. The frequency of RNA silencing was more affected by spacer sequence than
by spacer length, at least between 100 and 1800 bp. Since significant amounts of hairpin RNA against the NtFAD3 gene remained in the transgenic plants displaying a weak silencing phenotype, low degree of silencing was attributed to low
efficiency of hairpin RNA processing mediated by Dicer-like proteins. Our results show the possibility of producing a broad
range of the RNAi-induced silencing phenotypes by replacing the spacer sequence of RNAi construct. 相似文献
39.
40.
Nakagawa O Ono S Tsujimoto A Li Z Sasaki S 《Nucleosides, nucleotides & nucleic acids》2007,26(6-7):645-649
8-oxoguanosine, which is derived from the oxidation of guanosine (dG), is known to induce transversion mutations (G:C-->T:A) in DNA. The compounds with a small molecular weight for recognizing 8-oxoG were designed on the basis of the structure of the G-clamp, which is reported to have selective affinity toward guanosine. The G-clamp derivatives with the additional binding units toward 8-oxoG were effectively synthesized and named "8-oxoG-clamps." The 8-oxoG-clamp completely discriminated 8-oxoG from other nucleosides by fluorescence quenching. 相似文献