bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of Distinct Aspects of Photomorphogenesis via Targeted Expression of Mammalian Biliverdin Reductase in Transgenic Arabidopsis Plants
Authors: Montgomery Beronda L. , Yeh Kuo-Chen , Crepeau Marc W. , Lagarias J. Clark 
Published: July 2002

Abstract
The phenotypic consequences of targeted expression of mammalian biliverdin IXα reductase (BVR), an enzyme that metabolically inactivates the linear tetrapyrrole precursors of the phytochrome chromophore, are addressed in this investigation. Through comparative phenotypic analyses of multiple plastid-targeted and cytosolic BVR transgenic Arabidopsis plant lines, we show that the subcellular localization of BVR affects distinct subsets of light-mediated and light-independent processes in plant growth and development. Regardless of its cellular localization, BVR suppresses the phytochrome-modulated responses of hypocotyl growth inhibition, sucrose-stimulated anthocyanin accumulation, and inhibition of floral initiation. By contrast, reduced protochlorophyll levels in dark-grown seedlings and fluence-rate-dependent reduction of chlorophyll occur only in transgenic plants in which BVR is targeted to plastids. Together with companion analyses of the phytochrome chromophore-deficient hy1 mutant, our results suggest a regulatory role for linear tetrapyrroles within the plastid compartment distinct from their assembly with apophytochromes in the cytosol.
Developmental and Wound-, Cold-, Desiccation-, Ultraviolet-B-Stress-Induced Modulations in the Expression of the Petunia Zinc Finger Transcription Factor GeneZPT2-2
Authors: van der Krol Alexander R. , van Poecke Remco M.P. , Vorst Oscar F.J. , Voogd Charlotte , van Leeuwen Wessel , Borst-Vrensen Tanja W.M. , Takatsuji Hiroshi , van der Plas Linus H.W. 
Published: July 2002

Abstract
TheZPT2-2 gene belongs to the EPF gene family in petunia (Petunia hybrida), which encodes proteins with TFIIIA-type zinc-finger DNA-binding motifs. To elucidate a possible function for ZPT2-2, we analyzed its pattern of expression in relation to different developmental and physiological stress signals. The activity of the ZPT2-2promoter was analyzed using a firefly luciferase (LUC) reporter gene, allowing for continuous measurements of transgene activity in planta. We show that ZPT2-2::LUC is active in all plant tissues, but is strongly modulated in cotyledons upon germination, in leaves in response to desiccation, cold treatment, wounding, or ultraviolet-B light, and in petal tissue in response to pollination of the stigma. Analysis of mRNA levels indicated that the modulations in ZPT2-2::LUC expression reflect modulations in endogenous ZPT2-2 gene expression. The change in ZPT2-2::LUC activity by cold treatment, wounding, desiccation, and ultraviolet-B light suggest that the phytohormones ethylene and jasmonic acid are involved in regulating the expression of ZPT2-2. Although up-regulation of expression of ZPT2-2 can be blocked by inhibitors of ethylene perception, expression in plants is not induced by exogenously applied ethylene. The application of jasmonic acid does result in an up-regulation of gene activity and, thus, ZPT2-2 may play a role in the realization of the jasmonic acid hormonal responses in petunia.
ACX3, a Novel Medium-Chain Acyl-Coenzyme A Oxidase from Arabidopsis
Authors: Froman Byron E. , Edwards Patricia C. , Bursch Adam G. , Dehesh Katayoon 
Published: July 2002

Abstract
In a database search for homologs of acyl-coenzyme A oxidases (ACX) in Arabidopsis, we identified a partial genomic sequence encoding an apparently novel member of this gene family. Using this sequence information we then isolated the corresponding full-length cDNA from etiolated Arabidopsis cotyledons and have characterized the encoded recombinant protein. The polypeptide contains 675 amino acids. The 34 residues at the amino terminus have sequence similarity to the peroxisomal targeting signal 2 of glyoxysomal proteins, including the R-[I/Q/L]-X5-HL-XL-X15-22-C consensus sequence, suggesting a possible microsomal localization. Affinity purification of the encoded recombinant protein expressed in Escherichia colifollowed by enzymatic assay, showed that this enzyme is active on C8:0- to C14:0-coenzyme A with maximal activity on C12:0-coenzyme A, indicating that it has medium-chain-specific activity. These data indicate that the protein reported here is different from previously characterized classes of ACX1, ACX2, and short-chain ACX (SACX), both in sequence and substrate chain-length specificity profile. We therefore, designate this new gene AtACX3. The temporal and spatial expression patterns of AtACX3 during development and in various tissues were similar to those of theAtSACX and other genes expressed in glyoxysomes. Currently available database information indicates thatAtACX3 is present as a single copy gene.
Azuki Bean Cells Are Hypersensitive to Cadmium and Do Not Synthesize Phytochelatins
Authors: Inouhe Masahiro , Ito Rika , Ito Shoko , Sasada Naoki , Tohoyama Hiroshi , Joho Masanori 
Published: July 2002

Abstract
Suspension-cultured cells of azuki bean (Vigna angularis) as well as the original root tissues were hypersensitive to Cd (&lt;10 μm). Repeated subculturings with a sublethal level of Cd (1–10 μm) did not affect the subsequent response of cells to inhibitory levels of Cd (10–100 μm). The azuki bean cells challenged to Cd did not contain phytochelatin (PC) peptides, unlike tomato (Lycopersicon esculentum) cells that have a substantial tolerance to Cd (&gt;100 μm). Both of the cell suspensions contained a similar level of reduced glutathione (GSH) when grown in the absence of Cd. Externally applied GSH to azuki bean cells recovered neither Cd tolerance nor PC synthesis of the cells. Furthermore, enzyme assays in vitro revealed that the protein extracts of azuki bean cells had no activity converting GSH to PCs, unlike tomato. These results suggest that azuki bean cells are lacking in the PC synthase activity per se, hence being Cd hypersensitive. We concluded that the PC synthase has an important role in Cd tolerance of suspension-cultured cells.
Class III Pistil-Specific Extensin-Like Proteins from Tobacco Have Characteristics of Arabinogalactan Proteins
Authors: Bosch Maurice , Knudsen Jens Sommer , Derksen Jan , Mariani Celestina 
Published: July 2002

Abstract
Class III pistil-specific extensin-like proteins (PELPIII) are specifically localized in the intercellular matrix of tobacco (Nicotiana tabacum) styles. After pollination the majority of PELPIII are translocated into the callosic layer and the callose plugs of the pollen tubes, which could suggest a function of PELPIII in pollen tube growth. PELPIII may represent one of the chemical and/or physical factors from the female sporophytic tissue that contributes to the difference between in vivo and in vitro pollen tube growth. PELPIII glycoproteins were purified and biochemically characterized. Because of their high proline (Pro) and hydroxy-Pro (Hyp) content, PELPIII proteins belong to the class of Pro/Hyp-rich glycoproteins. The carbohydrate moiety of PELPIII is attached throughO-glycosidic linkages and comprises more than one-half the total glycoprotein. Deglycosylation of PELPIII revealed two backbones, both reacting with PELPIII-specific antibodies. N-terminal amino acid sequencing of these backbones showed that PELPIII is encoded by the MG14 and MG15 genes. Two heterogeneous N-terminal sequences of MG14 andMG15, both starting downstream of the predicted signal peptide cleavage site, seem to be present, which indicates a novel N-terminal processing. Monosaccharide analysis showed that the carbohydrate moiety of PELPIII almost completely consists of arabinose and galactose in an equal molar ratio. Carbohydrate linkage analysis showed terminal and 2-linked arabinofuranosyl residues, as well as terminal and 6-, 3-, and 3,6-linked galactopyranosyl residues to be present, indicating the presence of both extensin-like and Type II arabinogalactan oligosaccharide units. The ability of β-glucosyl Yariv reagent to bind with PELPIII confirmed the arabinogalactan protein-like characteristics of these proteins.
Spectroscopic Analysis of Desiccation-Induced Alterations of the Chlorophyllide Transformation Pathway in Etiolated Barley Leaves
Authors: Le Lay Pascaline , Böddi Béla , Kovacevic Dragan , Juneau Philippe , Dewez David , Popovic Radovan 
Published: July 2002

Abstract
Effects of water deficit on the chlorophyllide (Chlide) transformation pathway were studied in etiolated barley (Hordeum vulgare) leaves by analyzing absorption spectra and 77-K fluorescence spectra deconvoluted in components. Chlide transformations were examined in dehydrated leaves exposed to a 35-ms saturating flash triggering protochlorophyllide (Pchlide) and Chlide transformation processes. During the 90 min following the flash, we found that dehydration induced modifications of Chlide transformations, but no effect on Pchlide phototransformation into Chlide was observed. During this time, content of NADPH-Pchlide oxydoreductase in leaves did not change. Chlide transformation process in dehydrated leaves was characterized by the alteration of the Shibata shift process, by the appearance of a new Chlide species emitting at 692 nm, and by the favored formation of Chl(ide) A668F676. The formation of Chl(ide) A668F676, so-called “free Chlide,” was probably induced by disaggregation of highly aggregated Chlide complexes. Here, we offer evidence for the alteration of photoactive Pchlide regeneration process, which may be caused by the desiccation-induced inhibition of Pchlide synthesis.
Specific Association of Transcripts of tbzF andtbz17, Tobacco Genes Encoding Basic Region Leucine Zipper-Type Transcriptional Activators, with Guard Cells of Senescing Leaves and/or Flowers
Authors: Yang Seung Hwan , Berberich Thomas , Sano Hiroshi , Kusano Tomonobu 
Published: July 2002

Abstract
Induction by low temperature is a common feature of thelip19 subfamily members of the basic region leucine zipper gene family in plants. Here, we characterize two tobacco (Nicotiana tabacum) genes, tbzF andtbz17, belonging to the lip19 subfamily, whose gene products, TBZF and TBZ17, show 73% identity and are located in nuclei. They preferentially bind to DNA fragments spanning A-box/G-box and C-box/G-box hybrid motifs and show transactivation activity in cobombarded tobacco BY-2 cells, indicating they function as transcriptional activators. Transcripts of tbzF were detected at a high level in senescing leaves and flowers. In contrast,tbz17 transcripts could be shown to accumulate in aged leaves but not in flowers. In situ hybridization analysis revealed transcripts of tbzF and tbz17 to be predominantly located in guard cells and vascular tissues of senescing leaves. These results suggest that TBZF and TBZ17 are both involved in controlling gene transcription related to functions of guard cells in senescing leaves and that TBZF bifunctionally acts in floral development.
Catalytic center of an archaeal type 2 ribonuclease H as revealed by X‐ray crystallographic and mutational analyses
Authors: Muroya Ayumu , Tsuchiya Daisuke , Ishikawa Momoyo , Haruki Mitsuru , Morikawa Masaaki , Kanaya Shigenori , Morikawa Kosuke 
Published: July 2002

AbstractThe catalytic center of an archaeal Type 2 RNase H has been identified by a combination of X‐ray crystallographic and mutational analyses. The crystal structure of the Type 2 RNase H from Thermococcus kodakaraensis KOD1 has revealed that the N‐terminal major domain adopts the RNase H fold, despite the poor sequence similarity to the Type 1 RNase H. Mutational analyses showed that the catalytic reaction requires four acidic residues, which are well conserved in the Type 1 RNase H and the members of the polynucleotidyl transferase family. Thus, the Type 1 and Type 2 RNases H seem to share a common catalytic mechanism, except for the requirement of histidine as a general base in the former enzyme. Combined with the results from deletion mutant analyses, the structure suggests that the C‐terminal domain of the Type 2 RNase H is involved in the interaction with the DNA/RNA hybrid.
Experimental Analysis of the Heat Transfer Induced by Thermocapillary
Convection Around a Bubble
Authors: Arlabosse P. , Tadrist L. , Tadrist H. , Pantaloni J. 
Published: July 2002

Abstract
The surface tension driven flow in the liquid vicinity of gas bubbles on a heated wall and its contribution to the heat transfer are investigated experimentally in a configuration where surface tension force and buoyancy forces oppose one another. This liquid flow caused by the temperature gradient along the interface is called thermocapillary or thermal Marangoni convection. The studies were made with silicone oils of different viscosities so that a wide range of dimensionless numbers were encountered. The velocity fields are determined from the motion of carbon particles in the meridian plane of the bubble. The influence of the temperature gradient, the oil viscosity, and the bubble shape on the profiles along the interface and in the direction normal to the interface is analyzed. The temperature field is determined by holographic interferometry. For the axisymmetric problem, the interferograms are evaluated by solving the Abel-integral equation. From the isotherms, the temperature distribution along the bubble surface and in the liquid beneath the bubble is measured. To quantify the contribution of thermocapillarity to the heat transfer, the heat flux transferred by thermocapillarity is measured. A heat exchange law giving the increase in heat flux due to Marangoni convection in comparison to the conductive regime is proposed. [S0022-1481(00)70501-9]
Hematin Polymerization Assay as a High-Throughput Screen for Identification of New Antimalarial Pharmacophores
Authors: Kurosawa Yae , Dorn Arnulf , Kitsuji-Shirane Michiko , Shimada Hisao , Satoh Tomoko , Matile Hugues , Hofheinz Werner , Masciadri Raffaello , Kansy Manfred , Ridley Robert G. 
Published: July 2002

ABSTRACT

Hematin polymerization is a parasite-specific process that enables the detoxification of heme following its release in the lysosomal digestive vacuole during hemoglobin degradation, and represents both an essential and a unique pharmacological drug target. We have developed a high-throughput in vitro microassay of hematin polymerization based on the detection of
14
C-labeled hematin incorporated into polymeric hemozoin (malaria pigment). The assay uses 96-well filtration microplates and requires 12 h and a Wallac 1450 MicroBeta liquid scintillation counter. The robustness of the assay allowed the rapid screening and evaluation of more than 100,000 compounds. Random screening was complemented by the development of a pharmacophore hypothesis using the “Catalyst” program and a large amount of data available on the inhibitory activity of a large library of 4-aminoquinolines. Using these methods, we identified “hit” compounds belonging to several chemical structural classes that had potential antimalarial activity. Follow-up evaluation of the antimalarial activity of these compounds in culture and in the
Plasmodium berghei
murine model further identified compounds with actual antimalarial activity. Of particular interest was a triarylcarbinol (Ro 06-9075) and a related benzophenone (Ro 22-8014) that showed oral activity in the murine model. These compounds are chemically accessible and could form the basis of a new antimalarial medicinal chemistry program.
Safety, Tolerability, and Pharmacokinetics of Single Oral Doses of BCH-10652 in Healthy Adult Males
Authors: Smith Patrick F. , Forrest Alan , Ballow Charles H. , Martin David E. , Proulx Louise 
Published: July 2002

ABSTRACT

Racemic dOTC (BCH-10652) is a novel nucleoside reverse transcriptase inhibitor consisting of two enantiomers of 2′-deoxy-3′-oxa-4′-thiocytidine, (−)dOTC and (+)dOTC, that have both shown activity against human immunodeficiency virus type 1. The objectives of this study were to characterize the safety, tolerability, and stereospecific pharmacokinetics of single oral doses of racemic dOTC in healthy, nonsmoking adult male volunteers. Subjects received single oral doses of 100, 200, 400, 800, and 1,600 mg of racemic dOTC in a placebo-controlled, dose-rising, incomplete crossover study design, and the pharmacokinetics of both (+)dOTC and (−)dOTC were determined. At least six subjects were studied at each dose level, with each subject studied in three of five periods, receiving two different doses of racemic dOTC and one placebo dose. Plasma and urine drug concentrations were measured for 24 to 48 h after each dose. Pharmacokinetic models were fitted to the plasma concentrations of (+)dOTC and (−)dOTC using maximum likelihood and maximum a posteriori Bayesian procedures. Statistical hypothesis testing was by nonparametric analysis of variance (where possible) and, when tests with dose as a covariate were performed, by linear mixed-effects modeling. The mean terminal elimination half-lives for (+)dOTC and (−)dOTC were 15.3 h (coefficient of variation [CV], 28%) and 11.3 h (CV, 43%), respectively (
P
< 0.05). The mean CV for total oral clearance (liter/h/65 kg) was 17.5 (25%) for (+)dOTC and 21.5 (24%) for (−)dOTC; for oral steady-state volume of distribution (liter/65 kg), values were 61.8 (24%) for (+)dOTC and 34.1 (33%) for (−)dOTC (
P
< 0.05). The mean CV for renal clearance (liter/h/65 kg) of (+)dOTC was 10.4 (19%) and for (−)dOTC was 13.6 (20%) (
P
< 0.05). There was no significant effect of dose size on the pharmacokinetics of racemic dOTC. All doses were well tolerated, and no serious adverse events or laboratory abnormalities were observed.
In Vitro Activities of Rabeprazole, a Novel Proton Pump Inhibitor, and Its Thioether Derivative Alone and in Combination with Other Antimicrobials against Recent Clinical Isolates of
Helicobacter pylori
Authors: Kawakami Yoshiyuki , Akahane Takayuki , Yamaguchi Masaru , Oana Kozue , Takahashi Yuko , Okimura Yukie , Okabe Tadashi , Gotoh Akira , Katsuyama Tsutomu 
Published: July 2002

ABSTRACT

The MICs of rabeprazole sodium (RPZ), a newly developed benzimidazole proton pump inhibitor (PPI), against 133 clinical
Helicobacter pylori
strains revealed a higher degree of activity than the another two PPIs, lansoprazole and omeprazole. Time-kill curve assays of RPZ, when combined with amoxicillin, clarithromycin, or metronidazole, disclosed that synergistic effects were demonstrated in combination with each antibiotic examined. Moreover, no apparent antagonistic effect appeared among all of the strains tested.
In Vivo Activity and Pharmacokinetics of Ziracin (SCH27899), a New Long-Acting Everninomicin Antibiotic, in a Murine Model of Penicillin-Susceptible or Penicillin-Resistant Pneumococcal Pneumonia
Authors: Wang Erjian , Simard Marie , Bergeron Yves , Beauchamp Denis , Bergeron Michel G. 
Published: July 2002

ABSTRACT

The effectiveness of ziracin (SCH27899), a novel everninomicin, was at first investigated against lethal pneumonia caused by a penicillin-susceptible
Streptococcus pneumoniae
strain. A single intravenous injection of ziracin at a dose of 60 mg/kg of body weight given at 18 h postinfection protected 100% mice and led to the complete clearance of bacteria from their lungs. The activity of ziracin was observed to be the same as that of ceftriaxone: the 50% protective doses (PD
50
s) of ziracin and ceftriaxone were 24.8 and 24.6 mg/kg, respectively. Evaluation of this therapy with leukopenic mice showed that a single injection of ziracin protected 75% of these mice. A delay in therapy with ziracin, which was initiated at 48 h postinfection with 30 mg/kg given once daily for 3 days, resulted in an 83% survival rate of immunocompetent mice. The efficacy of ziracin was further compared to that of vancomycin against lethal pneumonia caused by a penicillin-resistant
S. pneumoniae
strain in leukopenic mice. The PD
50
s of ziracin and vancomycin were 40.5 and 44.2 mg/kg, respectively. Treatment with ziracin at 30 mg/kg once daily for 2 days (initiated 18 h postinfection) yielded an 83% survival rate and achieved complete eradication of the bacteria. The results were the same as those obtained with vancomycin administered at 15 mg/kg twice daily for 2 days. It is notable that the high survival rates for mice treated with ziracin were associated with effective eradication of the bacteria and rapid recovery of pulmonary tissues from pneumonia. The pharmacokinetic properties of ziracin, ceftriaxone, and vancomycin were estimated following intravenous administration of a single dose of 30 mg/kg to immunocompetent mice. The half-life of ziracin was observed to be longer than those of ceftriaxone and vancomycin (2.3 h versus 1.0 and 0.36 h in the bloodstream and 3 h versus 1.9 and 0.45 h in lung tissues). The areas under the concentration-time curves (AUCs) in lung tissue for ziracin versus those for ceftriaxone and vancomycin were 36 μg · h/g versus 20 and 9.5 μg · h/g. The prolonged half-life and high AUC for ziracin in tissue contributed to its excellent in vivo activities.
Novel Gene Cassettes and Integrons
Authors: Peters E. D. J. , Leverstein-van Hall M. A. , Box A. T. A. , Verhoef J. , Fluit A. C. 
Published: July 2002

ABSTRACT

An increase in multiresistant
Enterobacteriaceae
was observed at one of the departments of the University Medical Center Utrecht. Nine different integrons and 17 gene cassettes were found, including the new gene cassette
aadA8
. This cassette was highly related to
aadA3
and
aadA2
. In addition, an unknown promoter sequence was found for two integrons.
In70 of Plasmid pAX22, a
bla
VIM-1
-Containing Integron Carrying a New Aminoglycoside Phosphotransferase Gene Cassette
Authors: Riccio Maria Letizia , Pallecchi Lucia , Fontana Roberta , Rossolini Gian Maria 
Published: July 2002

ABSTRACT

An
Achromobacter xylosoxydans
strain showing broad-spectrum resistance to β-lactams (including carbapenems) and aminoglycosides was isolated at the University Hospital of Verona (Verona, Italy). This strain was found to produce metallo-β-lactamase activity and to harbor a 30-kb nonconjugative plasmid, named pAX22, carrying a
bla
VIM-1
determinant inserted into a class 1 integron. Characterization of this integron, named In70, revealed an original array of four gene cassettes containing, respectively, the
bla
VIM-1
gene and three different aminoglycoside resistance determinants, including an
aacA4
allele, a new
aph
-like gene named
aphA15
, and an
aadA1
allele. The
aphA15
gene is the first example of an
aph
-like gene carried on a mobile gene cassette, and its product exhibits close similarity to the APH(3′)-IIa aminoglycoside phosphotransferase encoded by Tn
5
(36% amino acid identity) and to an APH(3′)-IIb enzyme from
Pseudomonas aeruginosa
(38% amino acid identity). Expression of the cloned
aphA15
gene in
Escherichia coli
reduced the susceptibility to kanamycin and neomycin as well as (slightly) to amikacin, netilmicin, and streptomycin. Characterization of the 5′ and 3′ conserved segments of In70 and of their flanking regions showed that In70 belongs to the group of class 1 integrons associated with defective transposon derivatives originating from Tn
402
-like elements. The structure of the 3′ conserved segment indicates the closest ancestry with members of the In0-In2 lineage. In70, with its array of cassette-borne resistance genes, can mediate broad-spectrum resistance to most β-lactams and aminoglycosides.