Rice phloem thioredoxin h has the capacity to mediate its own cell-to-cell transport through plasmodesmata

Rice (Oryza sativa L.) phloem sieve tubes contain RPP13-1, a thioredoxin h protein that moves around the plant via the translocation stream. Such phloem-mobile proteins are thought to be synthesized in the companion cells prior to being transferred, through plasmodesmata, to the enucleate sieve-tube members. In this study, in-situ hybridization experiments confirmed that expression of RPP13-1 is restricted to companion cells within the mature phloem. To test the hypothesis that RPP13-1 enters the sieve tube, via plasmodesmata, recombinant RPP13-1 was expressed in Escherichia coli, extracted, purified and fluorescently labeled with fluorescein isothiocyanate (FITC) for use in microinjection experiments into tobacco (Nicotiana tabacum L.) mesophyll cells. The FITC-RPP13-1 moved from the injected cell into surrounding cells, whereas the E. coli thioredoxin, an evolutionary homolog of RPP13-1, when similarly labeled and injected, failed to move in this same experimental system. In addition, co-injection of RPP13-1 and FITC-dextrans established that RPP13-1 can induce an increase in plasmodesmal size exclusion limit to a value greater than 9.4 but less than 20 kDa. Nine mutant forms of RPP13-1 were constructed and tested for their capacity to move from cell to cell; two such mutants were found to be incapable of movement. Crystal-structure prediction studies were performed on wild-type and mutant RPP13-1 to identify the location of structural motifs required for protein trafficking through plasmodesmata. These studies are discussed with respect to plasmodesmal-mediated transport of macromolecules within the companion cell-sieve tube complex.

bor1-1, an Arabidopsis thaliana mutant that requires a high level of boron

bor1-1 (high boron requiring), an Arabidopsis thaliana mutant that requires a high level of B, was isolated. When the B concentration in the medium was reduced to 3 microM, the expansion of rosette leaves was severely affected in bor1-1 but not in wild-type plants. In a medium containing 30 microM B the mutant grew normally but showed female sterility, whereas the wild type was able to set seeds. These defects of the bor1-1 mutant were not detected with supplementation of 100 microM B. In vivo concentrations of B in bor1-1 mutants were lower than those of the wild type, especially in the inflorescence stems. Tracer experiments using 10B suggested that the mutant has defects in uptake and/or translocation of B. The mutation was mapped on the lower arm of chromosome 2.

Heliquinomycin, a new inhibitor of DNA helicase, produced by Streptomyces sp. MJ929-SF2 II. Structure determination of heliquinomycin

The structure of heliquinomycin which was isolated from the culture broth of Streptomyces sp. MJ929-SF2 was studied by NMR spectroscopies, X-ray crystallographic analysis and degradation experiments. Heliquinomycin is the first member of glycosylated rubromycins and griseorhodins group antibiotics.

Raw-starch-digesting and thermostable alpha-amylase from the yeast Cryptococcus sp. S-2: purification, characterization, cloning and sequencing

A starch-degrading enzyme produced by the yeast Cryptococcus sp. S-2 was purified in only one step by using an alpha-cyclodextrin-Sepharose 6B column, and was characterized as an alpha-amylase (EC 3.2.1.1). The molecular mass and isoelectric point of purified alpha-amylase (AMY-CS2) were estimated to be 66 kDa and 4.2 respectively. AMY-CS2 has raw-starch-digesting and raw-starch-absorbing activities. Furthermore it was shown to be thermostable. An open reading frame of the cDNA specified 611 amino acids, including a putative signal peptide of 20 amino acids. The N-terminal region of AMY-CS2 (from the N-terminus to position 496) had 49.7% similarity with the whole region of alpha-amylase from Aspergillus oryzae (Taka-amylase), whereas the C-terminal region had a sequence that was similar to the C-terminal region of glucoamylase G1 from A. niger. In addition, putative raw-starch-binding motifs exist in some amylolytic enzymes. A mutant AMY-CS2 that lacks the C-terminal domain lost not only its ability to bind or digest raw starch, but also its thermostability. Consequently it is possible that the putative raw-starch-binding domain of AMY-CS2 plays a role not only in the molecule's raw-starch-digesting ability but also in its thermostability.

Acid xylanase from yeast Cryptococcus sp. S-2: purification, characterization, cloning, and sequencing

A xylan-degrading enzyme produced by yeast Cryptococcus sp. S-2 was isolated and purified, and characterized as an endoxylanase (1,4-beta-D-xylan xylanohydrolase [EC 3.2.1.8]). We estimated the molecular weight and isoelectric point of purified xylanase (xyn-CS2) to be 22,000 and 7.4, respectively. This low-molecular-weight xylanase had an unusual pH optimum of 2.0, and showed 75% of maximal activity even at pH 1.0. An open reading frame of the cDNA specified 209 amino acids, including a putative signal peptide of 25 amino acids. The deduced amino acid sequence of xyn-CS2 shared significant similarities with the family-G xylanases of B. pumilus, C. acetobutylicum, T. reesei, and A. kawachii. Xyn-CS2 included two unique cysteine residues in a putative catalytic region, raising the possibility that these residues are at least partially responsible for its acidophilic nature.

Heliquinomycin, a new inhibitor of DNA helicase, produced by Streptomyces sp. MJ929-SF2 I. Taxonomy, production, isolation, physico-chemical properties and biological activities

Heliquinomycin was isolated as a part of a program designed to find inhibitors of DNA helicase from microbial sources. It was purified from the culture broth of Streptomyces sp. MJ929-SF2 by solvent extraction and serial chromatographies of centrifugal partition chromatography, Sephadex LH-20 and Capcell Pak C18 (HPLC). The isolated red powder was analyzed to have the molecular formula of C33H30O17. It inhibited partially purified DNA helicase from HeLa cell in a non-competitive manner with the inhibition constant (Ki) of 6.8 mM. Heliquinomycin exhibited biological activity against microorganisms including MRSA, and cultured cell lines.

Development of an atmospheric 222Rn concentration model using a hydrodynamic meteorological model: II. Three-dimensional research-purpose model

This paper describes a new type of three-dimensional numerical model for 222Rn transport in an atmospheric boundary layer. The model is a combination of a prognostic hydrodynamic meteorological model including a turbulence closure model and an atmospheric diffusion model for 222Rn. The first part provides the second part with the meteorological conditions needed for calculations of the 222Rn transport and diffusion. The model is capable of giving consideration to horizontal source distribution, complex terrain, and non-uniform and non-steady atmosphere. The model's results were compared with 222Rn field measurements in a mountain-valley area and represented qualitatively a typical diurnal variation of the 222Rn concentration in nocturnal drainage flows. The model was also applied to the transport of 222Rn in a seacoast area. These results indicated that the model could be effective as a research tool for numerical analysis of 222Rn behavior under various atmospheric conditions.

Development of an atmospheric 222Rn concentration model using a hydrodynamic meteorological model: I. One-dimensional practical model

A one-dimensional numerical model for 222Rn transport in an atmospheric boundary layer was developed. The model consists of two parts: a prognostic hydrodynamic model including a turbulence closure model and an atmospheric diffusion model for 222Rn. The first part predicts meteorological conditions to provide the second part with vertical turbulence conditions which affects the vertical motion of 222Rn near the Earth's surface. Calculations with the model are compared with 222Rn concentrations measured during a variety of meteorological conditions, from clear days with high radiation and low winds to cloudy days of low radiation with high winds. The model's results represent well the typical diurnal variations of the 222Rn concentrations.

Systemic lupus erythematosus with pulmonary hypertension

A 50-year-old Japanese female with a long history of Raynaud's phenomenon presented with progressive dyspnea due to pulmonary hypertension. The diagnosis of systemic lupus erythematosus was confirmed by proteinuria, lymphocytopenia, bilateral pleurisy, and a seizure of convulsion which was consistent with neurological manifestations of systemic lupus erythematosus, whereas the antinuclear antibody showed a low titer. Despite improvement in the activity of systemic lupus erythematosus, steroid treatment did not alter the progression of pulmonary hypertension, which increased in severity, eventually resulting in her death. We believe pulmonary hypertension to be an unusual but critical complication of systemic lupus erythematosus.

Effects of sulfate concentrations on the expression of a soybean seed storage protein gene and its reversibility in transgenic Arabidopsis thaliana

Transgenic expression of genes encoding the alpha' and beta subunits of beta-conglycinin, one of the major seed storage proteins of soybean (Glycine max [L.] Merr.), was analyzed in Arabidopsis thaliana (L.) Heynh. under conditions of sulfate deficiency. Temporal patterns of expression of both the intact beta subunit gene and the beta subunit gene promoter fused to the beta-glucuronidase (GUS) gene are similar in soil-less cultures using rockwool, suggesting that the response to sulfate deficiency is regulated mainly at the level of transcription. In hydroponic cultures with various concentrations of sulfate, expression of both the intact beta subunit gene and the beta subunit gene promoter-GUS fusion gene were negatively correlated to increased sulfate concentrations in the culture medium. Transfer of transgenic A. thaliana plants carrying the beta subunit gene promoter-GUS fusion from sulfate-deficient to sulfate-sufficient control medium caused GUS activity in developing siliques to be repressed within two days. A reverse shift, where the plants were transferred from the control to sulfate-deficient medium, caused GUS activity to become higher than that in seeds of the control plants within two days. These results indicate that the expression of the beta subunit gene promoter responds rapidly to changes of sulfate availability.

[A case of successful surgical retrieval of the intracoronary interlocked Palmaz-Schatz stent]

We presented a case of a 48-year-old male with failed delivery of the Palmaz-Schatz stent, who subsequently required CABG with successful retrieval of the stent. The patient had presented recurrent angina, approximately one and a half year since the last PTCA to the LAD. Re-PTCA was performed, but resulted in a severe local dissection. The stent implantation was tried, but was inadvertently dropped in the vessel. Since the patient was hemodynamically stable, we tried to remove the stent with Retriever endovascular snare, which ended up with interlocking the stent in the more proximal segment of the LAD and the snare itself was not removed. We, therefore, resort to the emergent operation, with successful retrieval of the snare device and the stent and carried on to the the bypass operation to the distal LAD without any complications. To our best knowledge, this is the first report in Japan for surgical retrieval of the Palmaz-Schatz stent, which was failed in delivery and interlocked in the vessel with retriever device.

Thioredoxin h is one of the major proteins in rice phloem sap

Sieve tubes play important roles in the transfer of nutrients as well as signals. Hundreds of proteins were found in pure phloem sap collected from rice (Oryza sativa L. cv. Kantou) plants through the cut ends of insect stylets. These proteins may be involved in nutrient transfer and signal transduction. To characterize the nature of these proteins, the partial amino-acid sequence of a 13-kDa protein, named RPP13-1, that was abundant in the pure phleom sap was determined. A cDNA clone of 687 bp, containing an open reading frame of 122 amino acids, was isolated using corresponding oligonucleotides as a probe. The deduced amino-acid sequence was very similar to that of the ubiquitous thiol redox protein, thioredoxin. The consensus sequences of thioredoxins are highly conserved. No putative signal peptide was identified. Antiserum against wheat thioredoxin h cross-reacted with RPP13-1 in the phloem sap of rice plants. RPP13-1 produced in Escherichia coli was reactive to antiserum against wheat thioredoxin h. Both E. coli-produced RPP13-1 and the phloem sap proteins catalyzed the reduction of the disulfide bonds of insulin in the presence of dithiothreitol. These results indicate that an active thioredoxin is a major protein translocating in rice sieve tubes.

A dioxygenase gene (Ids2) expressed under iron deficiency conditions in the roots of Hordeum vulgare

A lambda zapII cDNA library was constructed from mRNA isolated from Fe-deficient barley roots and screened with cDNA probes made from mRNA of Fe-deficient and Fe-sufficient (control) barley roots. Seven clones were selected. Among them a clone having the putative full-length mRNA of dioxygenase as judged by northern hybridization was selected and named Ids2 (iron deficiency-specific clone 2). Using a cDNA fragment as probe, two clones from the genomic library (lambda EMBL-III) were isolated and one was sequenced. The predicted amino acid sequence of Ids2 resembled that of 2-oxoglutarate-dependent dioxygenase. Ids2 is expressed in the Fe-deficient barley roots but is not in the leaves. The expression is repressed by the availability of Fe. Ids2 was also strongly expressed under Mn deficiency and weakly under Zn deficiency or excess NaCl (0.5%). The upstream 5'-flanking region of Ids2 has a root-specific cis element of the CaMV 35S promoter and a nodule-specific element of leghemoglobin, a metal regulatory element (MRE) and several Cu regulatory elements (UAS) of yeast metallothionein (CUP1).

Isolation of an Arabidopsis thaliana Mutant, mto1, That Overaccumulates Soluble Methionine (Temporal and Spatial Patterns of Soluble Methionine Accumulation)

We isolated Arabidopsis thaliana mutants that are resistant to ethionine, a toxic analog of methionine (Met). One of the mutants was analyzed further, and it accumulated 10- to 40-fold more soluble Met than the wild type in the aerial parts during the vegetative growth period. When the mutant plants started to flower, however, the soluble Met content in the rosette region decreased to the wild-type level, whereas that in the inflorescence apex region and in immature fruits was 5- to 8-fold higher than the wild type. These results indicate that the concentration of soluble Met is temporally and spatially regulated and suggest that soluble Met is translocated to sink organs after the onset of reproductive growth. The causal mutation, designated mto1, was a single, nuclear, semidominant mutation and mapped to chromosome 3. Accumulation profiles of soluble amino acids suggested that the mutation affects a later step(s) in the Met biosynthesis pathway. Ethylene production of the mutants was only 40% higher than the wild-type plants, indicating that ethylene production is tightly regulated at a step after Met synthesis. This mutant will be useful in studying the translocation of amino acids, as well as regulation of Met biosynthesis and other metabolic pathways related to Met.

[A case of ruptured left ventricular aneurysm due to syphilitic myocarditis]

This case involved a 20-year-old male who on May, 14, 1992, lost consciousness while working and went into a state of shock. He was taken to a hospital, where cardiac tamponade was diagnosed. He was later transferred to this hospital. Based on the results of echocardiography, coronary arteriography and left ventriculography, a ruptured ventricular aneurysm was diagnosed. The patient underwent emergency surgery. Serologic tests for syphilis performed at admission were definitely positive. Histopathological examination of the wall of the ventricular aneurysm disclosed fibrous myocarditis and peripheral coronary endarteritis accompanied by infiltration of plasma cells and lymphocytes. Immunohistological study revealed treponeme in the histiocytes of the aneurysmal wall. The diagnosis was a ruptured ventricular aneurysm caused by syphilitic myocarditis. Since the advent of penicillin therapy, cardiovascular syphilis, particularly syphilitic myocarditis, has become a rare disease. The chief interest of this case is that treponeme was detected in the lesion of myocarditis.

Expression of a Soybean (Glycine max [L.] Merr.) Seed Storage Protein Gene in Transgenic Arabidopsis thaliana and Its Response to Nutritional Stress and to Abscisic Acid Mutations

Among the three subunits of [beta]-conglycinin, the 7S seed storage protein of soybean (Glycine max [L.] Merr.), expression of the [beta] subunit gene is unique. Accumulation of the [beta] subunit is enhanced in sulfate-deficient soybean plants, and its mRNA levels increase when abscisic acid (ABA) is added to the in vitro cotyledon culture medium. Transgenic Arabidopsis thaliana lines carrying a gene encoding the [beta] subunit was constructed and grown under sulfate deficiency. Accumulation of both [beta] subunit mRNA and protein were enhanced in developing A. thaliana seeds. Accumulation of one of the A. thaliana seed storage protein mRNAs was also enhanced by sulfate deficiency, although the response was weaker than that observed for the soybean [beta] subunit mRNA. When the aba1-1 or abi3-1 mutations were crossed into the transgenic A. thaliana line, accumulation of the [beta] subunit was significantly reduced, whereas accumulation of the A. thaliana seed storage protein was not greatly affected. These results indicate that soybean and A. thaliana share a common mechanism for response to sulfate deficiency and to ABA, although the sensitivity is different between the species. The transgenic A. thaliana carrying the [beta] subunit gene of [beta]-conglycinin will be a good system to analyze these responses.

Expression of a gene specific for iron deficiency (Ids3) in the roots of Hordeum vulgare

To clone genes required for the synthesis of mugineic acid (MA) or for the transport of Fe(III)-MA, a lambda ZAPII cDNA library was constructed from poly(A)(+)-RNA isolated from Fe-deficient barley roots. The cDNA library was then used for differential screening of barley roots that had been grown in the presence and absence of iron. Seven clones that hybridized specifically to the probe for Fe deficiency were selected. One clone, presumably encoding a full-length mRNA, as deduced from Northern hybridization, was sequenced. The clone consisting of 1685 nucleotides encoded a putative protein of 169 amino acids and an M(r) of 18704. The gene was specifically expressed in the roots of iron-deficient barley. A search for homologies in a protein database (NBRF) revealed that the predicted protein product has a functional peptide domain that resembles that of 2-oxoglutarate-dependent dioxygenases.

Indirect utilization of the phytosiderophore mugineic acid as an iron source to rhizosphere fluorescent Pseudomonas

The phytosiderophore mugineic acid (MA) was studied as a source of iron for rhizosphere fluorescent pseudomonads. 55Fe supplied as Fe-MA was taken up by Pseudomonas putida WCS358, B10 and St3 grown under iron deficient conditions. The uptake decreased when the bacteria were grown in the presence of iron. However, no differences in uptake were observed when a siderophore deficient mutant was tested. Since ligand exchange between pseudobactin and MA was shown to occur rapidly with a half-life of 2 h, MA mediated iron uptake probably proceeds through this indirect mechanism. The ecological implications of these findings are discussed.

Improvement in long-term prognosis by coronary bypass surgery in patients with 3-vessel coronary disease--a matched case control study

We compared survival patterns in 61 medically treated and 78 surgically treated patients at a Japanese community hospital. The 2 groups were matched for presence of significant 3 vessel disease, resting ejection fraction of more than 40%, a bypassable left anterior descending artery, sex, and age. All surgical patients received saphenous vein grafts. The patients treated surgically had better 5 and 9 years survival rates than the medically treated patients (93% and 85% vs 74% and 55%, respectively; p < 0.01 by Cox-Mantel analysis). Five and 9 years rates of absence of ischemic events (non-fatal myocardial infarction and primary cardiac death) were also better in the surgical group than the medical group (92% and 87% vs 66% and 52%, respectively; p < 0.001). Of the surgically treated patients, 5 died perioperatively, 3 had late cardiac deaths and 2 had a nonfatal infarction. Among the medically treated patients, 16 had cardiac deaths, and 6 had non-fatal infarctions. Although our study was non-randomized, we have shown an advantage for surgical treatment of patients with 3-vessel coronary disease.