Isolation and characterization of microorganisms capable of hydrolysing the herbicide mefenacet     

Naoki Harada  Kazuhiro Takagi  Kunihiko Fujii 《Soil biology & biochemistry》2006,38(1):173-179

Three strains—Nocardioides sp. MFC-A, Rhodococcus rhodochrous MFC-B, and Stenotrophomonas sp. MFC-C—were newly isolated from rice soil or bark compost as microorganisms capable of cometabolically degrading mefenacet (2-benzothiazol-2-yloxy-N-methyl-acetanilide). Several other species belonging to the genera Nocardioides, Rhodococcus, and Stenotrophomonas were also capable of degrading mefenacet, suggesting that the ability is not specific to these isolates, but common at least in these genera. N-methylaniline and 2-benzothiazoloxy acetic acid were identified as the metabolites by liquid chromatography-mass spectrometry. Besides mefenacet, the isolates could degrade one or more other amide pesticides, such as flutolanil, mepronil, metolachlor, and pretilachlor. These results indicate that the strains Nocardioides sp. MFC-A, Rhodococcus rhodochrous MFC-B, and Stenotrophomonas sp. MFC-C degrade mefenacet via hydrolysis of the amide bond, but their substrate specificities differ.  相似文献   

Biotic and abiotic processes of nitrogen immobilization in the soil-residue interface     

Naoki Moritsuka  Junta Yanai  Takashi Kosaki 《Soil biology & biochemistry》2004,36(7):1141-1148

The interface between decaying plant residues and soil is a hotspot for microbial immobilization of soil inorganic N. Recent studies on forest and grassland soils have demonstrated that rapid abiotic immobilization of inorganic N is also induced by the presence of plant residues. We, therefore, examined (1) how N immobilization varies with distance from the soil-residue interface and (2) whether abiotic immobilization occurs in agricultural soils. Spatiotemporal changes of N immobilization in the soil-residue interface were evaluated using a box that enabled soil to be sampled in 2 mm increments from a 4 mm-thick residue compartment (RC). The RC was filled with paddy soil containing ground plant residue (rice bran, rice straw or beech leaves) uniformly at a rate of 50 g dry matter kg⁻¹. Soil in the surrounding compartments contained no residue. After aerobic incubation for 5, 15 and 30 days at 25 °C, soils in each compartment were analyzed. After 5 days, significant depletion of inorganic N occurred throughout a volume of soil extending at least 10 mm from the RC in all residue treatments, suggesting extensive diffusion of inorganic N towards the RC. The depletion within 10 mm of the RC amounted to 5.0, 4.3 and 3.4 mg for rice bran, rice straw and beech leaf treatment, respectively. On the other hand, microbial N had increased significantly in the RC of the rice bran and rice straw treatments (11 mg and 5.5 mg, respectively) and insignificantly in the RC of the beech leaf treatment (0.06 mg). This increase amounted to 221% (rice bran), 129% (rice straw) and 1.7% (beech leaves) of the decrease in inorganic N within 10 mm of each RC. Thereafter the rate of N mineralization exceeded that of immobilization, and inorganic N levels had recovered almost to their original level by 15 days (rice bran) and 30 days (rice straw and beech leaves). These results suggested the predominance of biotic immobilization in soil near rice bran and rice straw and of abiotic immobilization in soil near beech leaves. No significant increase in both microbial and soluble organic N in the vicinity of beech leaves after incubation for 5 days further suggested that the abiotic process was responsible for the transformation of inorganic N into the insoluble organic N.  相似文献   

A protein that binds to a cis-acting element of wheat histone genes has a leucine zipper motif   总被引：34，自引：0，他引：34  

T Tabata  H Takase  S Takayama  K Mikami  A Nakatsuka  T Kawata  T Nakayama  M Iwabuchi 《Science (New York, N.Y.)》1989,245(4921):965-967

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Aureusidin synthase: a polyphenol oxidase homolog responsible for flower coloration   总被引：1，自引：0，他引：1  

Nakayama T  Yonekura-Sakakibara K  Sato T  Kikuchi S  Fukui Y  Fukuchi-Mizutani M  Ueda T  Nakao M  Tanaka Y  Kusumi T  Nishino T 《Science (New York, N.Y.)》2000,290(5494):1163-1166

Aurones are plant flavonoids that provide yellow color to the flowers of some popular ornamental plants, such as snapdragon and cosmos. In this study, we have identified an enzyme responsible for the synthesis of aurone from chalcones in the yellow snapdragon flower. The enzyme (aureusidin synthase) is a 39-kilodalton, copper-containing glycoprotein catalyzing the hydroxylation and/or oxidative cyclization of the precursor chalcones, 2',4',6',4-tetrahydroxychalcone and 2',4',6',3,4-pentahydroxychalcone. The complementary DNA encoding aureusidin synthase is expressed in the petals of aurone-containing varieties. DNA sequence analysis revealed that aureusidin synthase belongs to the plant polyphenol oxidase family, providing an unequivocal example of the function of the polyphenol oxidase homolog in plants, i.e., flower coloration.  相似文献   

Inhibition of T cell receptor expression and function in immature CD4+CD8+ cells by CD4   总被引：14，自引：0，他引：14  

T Nakayama  C H June  T I Munitz  M Sheard  S A McCarthy  S O Sharrow  L E Samelson  A Singer 《Science (New York, N.Y.)》1990,249(4976):1558-1561

Most immature CD4+CD8+ thymocytes express only a small number of T cell receptor (TCR) molecules on their surface, and the TCR molecules they do express are only marginally capable of transducing intracellular signals. TCR expression and function was not intrinsically low in immature CD4+CD8+ thymocytes, but was found to be actively inhibited by CD4-mediated signals. Indeed, release of CD4+CD8+ thymocytes from CD4-mediated signals resulted in significant increases in both TCR expression and signaling function. These results suggest that, in CD4+CD8+ cells developing in the thymus, increased TCR expression and function requires release from CD4-mediated inhibition.  相似文献   

Collection,mapping, and annotation of over 28,000 cDNA clones from japonica rice   总被引：2，自引：0，他引：2  

Rice Full-Length cDNA Consortium;National Institute of Agrobiological Sciences Rice Full-Length cDNA Project Team  Kikuchi S  Satoh K  Nagata T  Kawagashira N  Doi K  Kishimoto N  Yazaki J  Ishikawa M  Yamada H  Ooka H  Hotta I  Kojima K  Namiki T  Ohneda E  Yahagi W  Suzuki K  Li CJ  Ohtsuki K  Shishiki T;Foundation of Advancement of International Science Genome Sequencing & Analysis Group  Otomo Y  Murakami K  Iida Y  Sugano S  Fujimura T  Suzuki Y  Tsunoda Y  Kurosaki T  Kodama T  Masuda H  Kobayashi M  Xie Q  Lu M 《Science (New York, N.Y.)》2003,301(5631):376-379

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Protostellar feedback halts the growth of the first stars in the universe     

Hosokawa T  Omukai K  Yoshida N  Yorke HW 《Science (New York, N.Y.)》2011,334(6060):1250-1253

The first stars fundamentally transformed the early universe by emitting the first light and by producing the first heavy elements. These effects were predetermined by the mass distribution of the first stars, which is thought to have been fixed by a complex interplay of gas accretion and protostellar radiation. We performed radiation-hydrodynamics simulations that followed the growth of a primordial protostar through to the early stages as a star with thermonuclear burning. The circumstellar accretion disk was evaporated by ultraviolet radiation from the star when its mass was 43 times that of the Sun. Such massive primordial stars, in contrast to the often-postulated extremely massive stars, may help explain the fact that there are no signatures of the pair-instability supernovae in abundance patterns of metal-poor stars in our galaxy.  相似文献   

Specialized inhibitory synaptic actions between nearby neocortical pyramidal neurons     

Ren M  Yoshimura Y  Takada N  Horibe S  Komatsu Y 《Science (New York, N.Y.)》2007,316(5825):758-761

We found that, in the mouse visual cortex, action potentials generated in a single layer-2/3 pyramidal (excitatory) neuron can reliably evoke large, constant-latency inhibitory postsynaptic currents in other nearby pyramidal cells. This effect is mediated by axo-axonic ionotropic glutamate receptor-mediated excitation of the nerve terminals of inhibitory interneurons, which connect to the target pyramidal cells. Therefore, individual cortical excitatory neurons can generate inhibition independently from the somatic firing of inhibitory interneurons.  相似文献   

Quantum criticality without tuning in the mixed valence compound beta-YbAlB4     

Matsumoto Y  Nakatsuji S  Kuga K  Karaki Y  Horie N  Shimura Y  Sakakibara T  Nevidomskyy AH  Coleman P 《Science (New York, N.Y.)》2011,331(6015):316-319

Fermi liquid theory, the standard theory of metals, has been challenged by a number of observations of anomalous metallic behavior found in the vicinity of a quantum phase transition. The breakdown of the Fermi liquid is accomplished by fine-tuning the material to a quantum critical point by using a control parameter such as the magnetic field, pressure, or chemical composition. Our high-precision magnetization measurements of the ultrapure f-electron-based superconductor β-YbAlB(4) demonstrate a scaling of its free energy that is indicative of zero-field quantum criticality without tuning in a metal. The breakdown of Fermi liquid behavior takes place in a mixed-valence state, which is in sharp contrast with other known examples of quantum critical f-electron systems that are magnetic Kondo lattice systems with integral valence.  相似文献   

Morphological modifications among oribatid mites (Acari: Oribatida) in relation to habitat differentiation in mangrove forests   总被引：2，自引：0，他引：2  

Shigenori Karasawa  Naoki Hijii 《Pedobiologia》2004,48(4):383-394

We examined morphological modifications among oribatid species in five microhabitats in mangrove forests in the Ryukyu Islands of Japan. A total of 89 oribatid species were recorded from canopy (leaves and branches), bark of flooded trunks (trunks of 0–50 cm high and knee roots), bark of other trunks higher than 50 cm, and littoral algae in mangrove forests, and the forest-floor soil in an adjacent bank forest. There were no significant differences in the body length, body width, and notogastral length among oribatid species from the five microhabitats. The mean sensillus length of the oribatid species from the forest-floor soil was about twice as long as that from the other microhabitats. Claw morphology was characterized by two attributes: number (monodactyly and tridactyly) and length. In the canopy and trunks, the proportion of tridactyl species was higher than that of monodactyl species. On the other hand, the proportion of tridactyl species in the forest-floor soil accounted for only about 20%, and that in the flooded trunks and littoral algae approximated to zero. The mean claw length was larger in the oribatid species from the flooded trunks and littoral algae than in both monodactyl and tridactyl species from every other microhabitat. Trydactyl species with short claws in the arboreal environments might have been selected by a compromise between grip and mobility for unpredictable environmental changes such as wind and rain. The dominance of monodactyl species with a longer claw in the littoral environments implies a consequence of selection for regular tidal flooding, which requires oribatids to grip tighter on the substrate. The modifications in claw morphology of oribatid mites in mangrove forest might be interpreted as adaptations to a difference in the predictability of the environmental conditions of microhabitats.  相似文献