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141.
Restriction fragment length polymorphism (RFLP) of the total DNA ofBipolaris andCurvularia species was analysed using arbitrarily chosen genomic clones of DNA fromCurvularia lunata andBipolaris maydis as probes. Clear differences among species in both genera, resulting in different banding positions, were obtained with some probe-enzyme combinations. Intraspecific polymorphism in banding positions with these probe-enzyme combinations was slight. These analyses allow discrimination between the species. DNA fingerprinting with intrageneric probes is a potentially useful tool for species separation and identification inBipolaris andCurvularia when coupled with another characteristic such as conidial morphology.Curvularia aeria comb. nov. was proposed forCurvularia lunata var.aeria on the basis of differences in RFLP banding patterns and differences in conidial morphology. 相似文献
142.
Yoshifumi Matsumoto Chihiro Hiramatsu Yuka Matsushita Norihiro Ozawa Ryuichi Ashino Makiko Nakata Satoshi Kasagi Anthony Di Fiore Colleen M. Schaffner Filippo Aureli Amanda D. Melin Shoji Kawamura 《Molecular ecology》2014,23(7):1799-1812
New World monkeys exhibit prominent colour vision variation due to allelic polymorphism of the long‐to‐middle wavelength (L/M) opsin gene. The known spectral variation of L/M opsins in primates is broadly determined by amino acid composition at three sites: 180, 277 and 285 (the ‘three‐sites’ rule). However, two L/M opsin alleles found in the black‐handed spider monkeys (Ateles geoffroyi) are known exceptions, presumably due to novel mutations. The spectral separation of the two L/M photopigments is 1.5 times greater than expected based on the ‘three‐sites’ rule. Yet the consequence of this for the visual ecology of the species is unknown, as is the evolutionary mechanism by which spectral shift was achieved. In this study, we first examine L/M opsins of two other Atelinae species, the long‐haired spider monkeys (A. belzebuth) and the common woolly monkeys (Lagothrix lagotricha). By a series of site‐directed mutagenesis, we show that a mutation Y213D (tyrosine to aspartic acid at site 213) in the ancestral opsin of the two alleles enabled N294K, which occurred in one allele of the ateline ancestor and increased the spectral separation between the two alleles. Second, by modelling the chromaticity of dietary fruits and background leaves in a natural habitat of spider monkeys, we demonstrate that chromatic discrimination of fruit from leaves is significantly enhanced by these mutations. This evolutionary renovation of L/M opsin polymorphism in atelines illustrates a previously unappreciated dynamism of opsin genes in shaping primate colour vision. 相似文献
143.
Morimura K Yamazaki C Hattori Y Makabe H Kamo T Hirota M 《Bioscience, biotechnology, and biochemistry》2007,71(11):2837-2840
A chromene-type compound, daedalin A (1), was isolated from mycelial culture broth of Daedalea dickinsii. Based on spectroscopic data, the structure of 1 was found to be (2R)-6-hydroxy-2-hydroxymethyl-2-methyl-2H-chromene. Daedalin A (1) strongly inhibited the activity of tyrosinase (IC(50): 194 muM). In addition, 1 also showed 1,1-diphenyl-2-picrylhydrazyl scavenging activity (IC(50): 16.9 microM) and superoxide anion scavenging activity (IC(50): 28.5 microM). 相似文献
144.
Nishiya T Matsumoto K Maekawa S Kajita E Horinouchi T Fujimuro M Ogasawara K Uehara T Miwa S 《The Journal of biological chemistry》2011,286(11):9009-9019
Inducible nitric-oxide synthase (iNOS, NOS2) plays a prominent role in macrophage bactericidal and tumoricidal activities. A relatively large amount of NO produced via iNOS, however, also targets the macrophage itself for apoptotic cell death. To uncover the intrinsic mechanisms of iNOS regulation, we have characterized the SPRY domain- and SOCS box-containing protein 1 (SPSB1), SPSB2, and SPSB4 that interact with the N-terminal region of iNOS in a D-I-N-N-N sequence-dependent manner. Fluorescence microscopy revealed that these SPSB proteins can induce the subcellular redistribution of iNOS from dense regions to diffused expression in a SOCS box-dependent manner. In immunoprecipitation studies, both Elongin C and Cullin-5, components of the multi-subunit E3 ubiquitin ligase, were found to bind to iNOS via SPSB1, SPSB2, or SPSB4. Consistently, iNOS was polyubiquitinated and degraded in a proteasome-dependent manner when SPSB1, SPSB2, or SPSB4 was expressed. SPSB1 and SPSB4 had a greater effect on iNOS regulation than SPSB2. The iNOS N-terminal fragment (residues 1-124 of human iNOS) could disrupt iNOS-SPSB interactions and inhibit iNOS degradation. In lipopolysaccharide-treated macrophages, this fragment attenuated iNOS ubiquitination and substantially prolonged iNOS lifetime, resulting in a corresponding increase in NO production and enhanced NO-dependent cell death. These results not only demonstrate the mechanism of SPSB-mediated iNOS degradation and the relative contributions of different SPSB proteins to iNOS regulation, but also show that iNOS levels are sophisticatedly regulated by SPSB proteins in activated macrophages to prevent overproduction of NO that could trigger detrimental effects, such as cytotoxicity. 相似文献
145.
146.
Chihiro Kachi-TerajimaHitoshi Miyasaka Tomohiko IshiiKen-ichi Sugiura Masahiro Yamashita 《Inorganica chimica acta》2002,332(1):210-215
The ligand substitution reaction of Ru2(O2CCH3)4Cl with 2-amino-4,6-dimethylpyrimidine (Hadmpym) under gentle refluxing conditions in methanol led to the formation of a bridging-ligand mono-substituted compound, [Ru2(O2CCH3)3(admpym)(Cl)(MeOH)] (1). Compound 1 crystallized in monoclinic space group P21/n (no. 14) with a=8.3074(8) Å, b=12.3722(8) Å, c=18.913(1) Å, β=95.559(3)°, V=1934.8(3) Å3, and Z=4. Temperature dependence of the magnetic susceptibility of 1 revealed it to be in a spin ground state S=3/2 arising from the electronic configuration of σ2π4δ2(δ*π*)3. Compound 1 undergoes three metal-centered redox reactions in electrochemistry: E1/2 (ox)=+0.72 V (Ia/Ic<1, ΔEp=0.17 V); E1/2 (1,red)=−0.65 V (Ia/Ic≈1, ΔEp=0.10 V); and E1/2 (2,red)=−1.80 V (Ia/Ic?1, ΔEp=0.16 V). Then, the redox species produced by electrolysis were characterized by spectroscopic studies. 相似文献
147.
148.
Takahashi K Mitoma J Hosono M Shiozaki K Sato C Yamaguchi K Kitajima K Higashi H Nitta K Shima H Miyagi T 《The Journal of biological chemistry》2012,287(18):14816-14826
Modulation of levels of polysialic acid (polySia), a sialic acid polymer, predominantly associated with the neural cell adhesion molecule (NCAM), influences neural functions, including synaptic plasticity, neurite growth, and cell migration. Biosynthesis of polySia depends on two polysialyltransferases ST8SiaII and ST8SiaIV in vertebrate. However, the enzyme involved in degradation of polySia in its physiological turnover remains uncertain. In the present study, we identified and characterized a murine sialidase NEU4 that catalytically degrades polySia. Murine NEU4, dominantly expressed in the brain, was found to efficiently hydrolyze oligoSia and polySia chains as substrates in sialidase in vitro assays, and also NCAM-Fc chimera as well as endogenous NCAM in tissue homogenates of postnatal mouse brain as assessed by immunoblotting with anti-polySia antibodies. Degradation of polySia by NEU4 was also evident in neuroblastoma Neuro2a cells that were co-transfected with Neu4 and ST8SiaIV genes. Furthermore, in mouse embryonic hippocampal primary neurons, the endogenously expressed NEU4 was found to decrease during the neuronal differentiation. Interestingly, GFP- or FLAG-tagged NEU4 was partially co-localized with polySia in neurites and significantly suppressed their outgrowth, whereas silencing of NEU4 showed the acceleration together with an increase in polySia expression. These results suggest that NEU4 is involved in regulation of neuronal function by polySia degradation in mammals. 相似文献
149.
Distinct roles of TIR and non-TIR regions in the subcellular localization and signaling properties of MyD88 总被引:1,自引:0,他引:1
MyD88 is a cytoplasmic adaptor protein that is critical for Toll-like receptor (TLR) signaling. The subcellular localization of MyD88 is characterized as large condensed forms in the cytoplasm. The mechanism and significance of this localization with respect to the signaling function, however, are currently unknown. Here, we demonstrate that MyD88 localization depends on the entire non-TIR region and that the correct cellular targeting of MyD88 is indispensable for its signaling function. The Toll-interleukin I receptor-resistance (TIR) domain does not determine the subcellular localization, but it mediates interaction with specific TLRs. These findings reveal distinct roles for the TIR and non-TIR regions in the subcellular localization and signaling properties of MyD88. 相似文献
150.
Sugiura M Ogami S Kusumi M Un S Rappaport F Boussac A 《The Journal of biological chemistry》2012,287(16):13336-13347
The main cofactors that determine the photosystem II (PSII) oxygen evolution
activity are borne by the D1 and D2 subunits. In the cyanobacterium
Thermosynechococcus elongatus, there are three
psbA genes coding for D1. Among the 344 residues
constituting D1, there are 21 substitutions between PsbA1 and PsbA3, 31 between
PsbA1 and PsbA2, and 27 between PsbA2 and PsbA3. Here, we present the first
study of PsbA2-PSII. Using EPR and UV-visible time-resolved absorption
spectroscopy, we show that: (i) the time-resolved EPR spectrum of TyrZ• in the
(S3TyrZ•)′ is slightly modified; (ii) the split EPR signal
arising from TyrZ• in the (S2TyrZ•)′ state induced by near-infrared
illumination at 4.2 K of the S3TyrZ state is significantly
modified; and (iii) the slow phases of P680+⋅ reduction by TyrZ are
slowed down from the hundreds of μs time range to the ms time range,
whereas both the S1TyrZ• → S2TyrZ and
the S3TyrZ• → S0TyrZ + O2
transition kinetics remained similar to those in PsbA(1/3)-PSII. These results
show that the geometry of the TyrZ phenol and its environment, likely
the Tyr-O···H···Nϵ-His bonding,
are modified in PsbA2-PSII when compared with PsbA(1/3)-PSII. They also point to
the dynamics of the proton-coupled electron transfer processes associated with
the oxidation of TyrZ being affected. From sequence comparison, we
propose that the C144P and P173M substitutions in PsbA2-PSII
versus PsbA(1/3)-PSII, respectively located upstream of the
α-helix bearing TyrZ and between the two α-helices
bearing TyrZ and its hydrogen-bonded partner, His-190, are
responsible for these changes. 相似文献