Quantum critical phenomena of unconventional superconductors: U(1) gauge model of link Cooper pair

In this paper we shall study quantum critical behavior of lattice model of unconventional superconductors (SC) that was proposed in the previous papers. In this model, the Cooper-pair (CP) field is defined on lattice links in order to describe d-wave SC. The CP field can be regarded as a U(1) lattice gauge field, and the SC phase transition takes place as a result of the phase coherence of the CP field. Effects of the long-range Coulomb interactions between the CP's and fluctuations of the electromagnetic field are taken into account. We investigate the phase structure of the model and the critical behavior by means of the Monte Carlo simulations. We find that the parameter, which controls the fluxes (vortices) of the CP, strongly influences the phase structure. In three-dimensional case, the model has rich phase structure. In particular there is a "monopole proliferation" phase transition besides the SC phase transition. Depending on the parameters, this transition exists within the SC phase or takes place simultaneously with the SC transition. This new type of transition is relevant for unconventional SC's with strong spatial three-dimensionality and to be observed by experiments.Comment: 13pages,25figure

Tranformation of Mutualistic Fungal Acremonium Endophyte

Conditions have been developed for transforming protoplast of the Acremonium endophyte by PEG 4000 and electroporation. Transformation by PEG exhibited a higher number of tranformants than by electroporation. Intregation of iaaM gene into the genome was examined by PCR and Southern blot hybridization analysis. PCR product showed that transformants banded at around 1.7 kb corresponding to the size of iaaM gene. Hybridizationn of the digest of genomic DNA with iaaM gene as DNA probe showed that the number of hybridized band signals was different between tranformant and non-transformant. These result might indicate that PEG is an effective method for the transformation of Acremonium endopyhte and that there are repeated copies of the iaaM homologous sequences in the genome of Acremonium. Key words: Acremonium sp., endhophyte, transformation, iaaM gene, hph gen

Quantum Phase Transition in Lattice Model of Unconventional Superconductors

In this paper we shall introduce a lattice model of unconventional superconductors (SC) like d-wave SC in order to study quantum phase transition at vanishing temperature ($T$). Finite-$T$ counterpart of the present model was proposed previously with which SC phase transition at finite $T$ was investigated. The present model is a noncompact U(1) lattice-gauge-Higgs model in which the Higgs boson, the Cooper-pair field, is put on lattice links in order to describe d-wave SC. We first derive the model from a microscopic Hamiltonian in the path-integral formalism and then study its phase structure by means of the Monte Carlo simulations. We calculate the specific heat, monopole densities and the magnetic penetration depth (the gauge-boson mass). We verified that the model exhibits a second-order phase transition from normal to SC phases. Behavior of the magnetic penetration depth is compared with that obtained in the previous analytical calculation using XY model in four dimensions. Besides the normal to SC phase transition, we also found that another second-order phase transition takes place within the SC phase in the present model. We discuss physical meaning of that phase transition.Comment: 12 pages, 10 figures, references added, some discussion on the results adde

エンドウ原形質膜におけるATPアーゼとホスファチジルイノシトールリン資質リン酸化酵素の共精製

The plasma membrance ATPase was partially purified by a linear glycerol density gradient centrifugation of the detergent-solubilized plasma membrance poteins and subsequent separation by a size-exclusion column chromatogrphy. A purified ATPase preparation is shown to contain a 97.6kDa protein that was cross-reacted with an antibody raised against mung bean H+-ATPase. The preparation also exhibited the phosphorylation of exogenous phosphatidylionsitol(PI) when supplized with [γ-32P]ATP. These results indicate that one form plasma membrance ATPase is co-purified with PI kinase.エンドウの上胚軸組織から分離した原形質膜画分におけるATPアーゼとホスファチジルイノシトールリン脂質リン酸化酵素との相互作用を解析する目的で、双方の原形質膜画分からの可溶化とそれらの部分精製を試みた。原形質膜のTritonX－100可溶化画分をグリセロール連続密度勾配遠心分画に供し、得られた活性画分をさらに分子ふるいカラムクロマトグラフィーによって分離した。この結果、ＡＴＰアーゼとホスファチジルイイノシトールリン脂質リン酸化酵素は共精製され、非変性条件下では双方の活性を分けることができなかった

共生真菌アクレモニウムエンドファイトの形質転換

Conditions have been developed for transforming protoplasts of the Acremonium endophyte by PEG 4000 and electroporation. Transformation by PEG exhibited a higher number of transformants than by electroporation. lntegration of iaaM gene into the genome was examined by PCR and Southern blot hybridization analysis. PCR product showed that transformants banded at around 1.7 kb corresponding to the size of iaaM gene. Hybridization of the digests of genomic DNA with iaaM gene as DNA probe showed that the number of hybridized band signals was different between transformant and non-transformant. These results might indicate that PEG is an effective method for the transformation of Acremonium endophyte and that there are repeated copies of the iaaM homologous sequences in the genome of Acremonium.アクレモニウムエンドファイトの形質転換の条件を検討した。アクレモニウムエンドファイトからプロトプラストを調製し、PEG4000とエレクトロポレーションを用いて形質転換を試みた。その結果、PEGで形質転換すると、エレクトロポレーションによる場合よりも多くの形質転換体が得られた。PCR解析によってiaaM遺伝子のゲノムへの導入を確認したところ、形質転換体のPCR産物はiaaM遺伝子のサイズに相当する約1.7kbのバンドを持っていた。一方、iaaM遺伝子をプローブとしたサザンブロット解析においては、形質転換体と非形質転換体の間にはハイブリダイズした断片数に違いがあることが明らかとなった。以上の結果は、アクレモニウムエンドファイトの形質転換にはPEG法が有効であること、アクレモニウムエンドファイトのゲノム中にはiaaM遺伝子様配列の反復コピーが存在することを示唆している

Higgs mechanism and superconductivity in U(1) lattice gauge theory with dual gauge fields

We introduce a U(1) lattice gauge theory with dual gauge fields and study its phase structure. This system is motivated by unconventional superconductors like extended s-wave and d-wave superconductors in the strongly-correlated electron systems. In this theory, the "Cooper-pair" field is put on links of a cubic lattice due to strong on-site repulsion between electrons in contrast to the ordinary s-wave Cooper-pair field on sites. This Cooper-pair field behaves as a gauge field dual to the electromagnetic U(1) gauge field. By Monte Carlo simulations we study this lattice gauge model and find a first-order phase transition from the normal state to the Higgs (superconducting) state. Each gauge field works as a Higgs field for the other gauge field. This mechanism requires no scalar fields in contrast to the ordinary Higgs mechanism.Comment: 4 pages, 6 figure

Finite-temperature phase diagram of two-component bosons in a cubic optical lattice: Three-dimensional t-J model of hard-core bosons

We study the three-dimensional bosonic t-J model, i.e., the t-J model of "bosonic electrons", at finite temperatures. This model describes the $s={1 \over 2}$ Heisenberg spin model with the anisotropic exchange coupling $J_{\bot}=-\alpha J_z$ and doped {\it bosonic} holes, which is an effective system of the Bose-Hubbard model with strong repulsions. The bosonic "electron" operator $B_{r\sigma}$ at the site $r$ with a two-component (pseudo-)spin $\sigma (=1,2)$ is treated as a hard-core boson operator, and represented by a composite of two slave particles; a "spinon" described by a Schwinger boson (CP$^1$ boson) $z_{r\sigma}$ and a "holon" described by a hard-core-boson field $\phi_r$ as $B_{r\sigma}=\phi^\dag_r z_{r\sigma}$. By means of Monte Carlo simulations, we study its finite-temperature phase structure including the $\alpha$ dependence, the possible phenomena like appearance of checkerboard long-range order, super-counterflow, superfluid, and phase separation, etc. The obtained results may be taken as predictions about experiments of two-component cold bosonic atoms in the cubic optical lattice.Comment: 8 pages, 14 figures, Size of figures has been adjuste

A Volatile Substance, β-Caryophyllene, from Talaromyces wortmannii Promotes Growth and Tolerance to Diseases on Several Plants

A plant growth-promoting fungus, Talaromyces wortmannii strain FS2 was isolated from an agricultural field at Okayama Pref. FS2 enhanced seed germination, root elongation and leaf growth of Brassica rapa var perviridis (Komatsuna). Such plant growth-promoting effect was observed in the same sealed chamber where FS2 was cultured on PDA medium separated from seedlings, suggesting effective volatile compound(s). GC‒MS analysis showed that FS2 emitted at least seven terpenoids, of which a volatile was identified as β‒caryophyllene. β‒caryophyllene alone promoted the growth of cucumber, Nicotiana benthamiana and barley. Furthermore β‒caryophyllene increased the yield of cucumber fruits. Interestingly, we found that β‒caryophyllene conditioned these plants to be resistant to respective diseases caused by Colletotrichum orbiculare, Botrytis cinerea or Blumeria graminis f. sp hordei. The findings indicate that β‒caryophyllene has desirable dual features and therefore, it is available to cultivation of many crops.岡山県総社市の圃場から分離した植物生育促進菌Talaromyces wortmannii FS2が生産するβ-caryophylleneは，コマツナ（アブラナ科）のみならず，キュウリ（ウリ科），タバコ（ナス科）およびオオムギ（イネ科）など広汎な植物に対して，生育促進作用および耐病性増進作用を示したことから，有用な農業資材として利用可能であるものと考察した

病原菌シグナルによるエンドウ原形質膜におけるホスファチジルイノシトールリン脂質のリン酸化とリゾリン脂質生成の制御

Effects of elicitor and suppressor from a pea pathogen, Mycosphaerella pinodes, on Pl etabolism in pea plasma membrane were examined in vitro. The elicitor induced rapid phosphorylation of phosphatidylinositols as well as production of lysophospholipid in plasma membranes, but these responses were severely inhibited by the suppressor. These results indicate that a membrane-associated phospholipase A is regulated coordinately by fungal signals, together with Pl metabolism, and that it may participate in signal transduction pathways leading to defense responses. To evaluate a possible rote of phospholipase A activation in induction of a pea defense response, the effect of free fatty acid on induction of a phytoalexin accumulation was also examined. When pea leaves were treated with linoleic- or linolenic acid, most commonly released in plant cells by phospholipase A, the accumulation of pisatin was induced even in the absence of the elicitor. It is, therefore, conceivable that free fatty acid(s) released from plasma membrane is also implicated in the early stage of elicitor-signal transduction in pea.エンドウの上胚軸組織により分離した原形質膜画分を褐紋病菌の生産するエリシターで処理すると、ホスファチジルイノシトールリン脂質の急速なリン酸化とリゾリン脂質の生成が誘導されたが、同菌より調製したサプレッサーの共存下では双方とも著しく阻害された。本結果は、ポリホスホイノシチド代謝系と同調的に作動するホリパーゼA活性化が存在すること、さらに、原形質膜における病原菌シグナルの受容・応答には複数の資質代謝系が介在する可能性を示唆している。一方、ホスホリパーゼAの活性化の役割を調べる目的で、本酵素によって原形質膜から生成されると考えられる脂肪酸(リノール酸ならびにリノレン酸)をエンドウ葉に処理したところ、エリシターの非存在下においてもファイトアレキシンであるピサチンの生成が誘導されることが示された。以上から、ポリホスホイノシチド代謝系と同調的に働くホスホリパーゼAがエリシターシグナルの初期伝達に深く関連しているものと考えられた