bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthetic Pathways of Brassinolide in Arabidopsis
Authors: Noguchi Takahiro , Fujioka Shozo , Choe Sunghwa , Takatsuto Suguru , Tax Frans E. , Yoshida Shigeo , Feldmann Kenneth A. 
Published: July 2002

Abstract
Our previous studies on the endogenous brassinosteroids (BRs) in Arabidopsis have provided suggestive evidence for the operation of the early C6-oxidation and the late C6-oxidation pathways, leading to brassinolide (BL) in Arabidopsis. However, to date the in vivo operation of these pathways has not been fully confirmed in this species. This paper describes metabolic studies using deuterium-labeled BRs in wild-type and BR-insensitive mutant (bri1) seedlings to establish the intermediates of the biosynthetic pathway of BL in Arabidopsis. The first evidence for the conversion of campestanol to 6-deoxocathasterone and the conversion of 6-deoxocathasterone to 6-deoxoteasterone is provided. The later biosynthetic steps (6-deoxoteasterone → 3-dehydro-6-deoxoteasterone → 6-deoxotyphasterol → 6-deoxocastasterone → 6α-hydroxycastasterone → castasterone → BL) were demonstrated by stepwise metabolic experiments. Therefore, these studies complete the documentation of the late C6-oxidation pathway. The biosynthetic sequence involved in the early C6-oxidation pathway (teasterone → 3-dehydroteasterone → typhasterol → castasterone → BL) was also demonstrated. These results show that both the early and late C6-oxidation pathways are functional in Arabidopsis. In addition we report two new observations: the presence of a new branch in the pathway, C6 oxidation of 6-deoxotyphasterol to typhasterol, and increased metabolic flow in BR-insensitive mutants.
Plant Signaling 2000. Cross Talk Among Geneticists, Physiologists, and Ecologists
Authors: Cosgrove Daniel J. , Gilroy Simon , Kao Teh-hui , Ma Hong , Schultz Jack C. 
Published: July 2002

Abstract
Plants respond in complex ways to their environment, to their internal physiological status, and to the activity of other plants, pathogens, herbivores, and organisms. Plant Signaling 2000, a symposium sponsored by the Penn State Intercollege Graduate Program in Plant Physiology (May 18–20, 2000), explored the machinery underlying these responses and their potential for cross talk. We recount here some of the major themes emerging from this interdisciplinary symposium, which ranged from genetic and biochemical analyses of signaling pathways in Arabidopsis and other model plants to field studies of plants responding to insect damage.
A Genomics Approach to the Comprehensive Analysis of the Glutathione S-Transferase Gene Family in Soybean and Maize
Authors: McGonigle Brian , Keeler Sharon J. , Lau Sze-Mei Cindy , Koeppe Mary K. , O'Keefe Daniel P. 
Published: July 2002

Abstract
By BLAST searching a large expressed sequence tag database for glutathione S-transferase (GST) sequences we have identified 25 soybean (Glycine max) and 42 maize (Zea mays) clones and obtained accurate full-length GST sequences. These clones probably represent the majority of members of the GST multigene family in these species. Plant GSTs are divided according to sequence similarity into three categories: types I, II, and III. Among these GSTs only the active site serine, as well as another serine and arginine in or near the “G-site” are conserved throughout. Type III GSTs have four conserved sequence patches mapping to distinct structural features. Expression analysis reveals the distribution of GSTs in different tissues and treatments: Maize GSTI is overall the most highly expressed in maize, whereas the previously unknown GmGST 8 is most abundant in soybean. Using DNA microarray analysis we observed increased expression among the type III GSTs after inducer treatment of maize shoots, with different genes responding to different treatments. Protein activity for a subset of GSTs varied widely with seven substrates, and any GST exhibiting greater than marginal activity with chloro-2,4 dinitrobenzene activity also exhibited significant activity with all other substrates, suggesting broad individual enzyme substrate specificity.
Cloning and Characterization of a Receptor-Like Protein Kinase Gene Associated with Senescence
Authors: Hajouj Taleb , Michelis Regina , Gepstein Shimon 
Published: July 2002

Abstract
Senescence-associated genes are up-regulated during plant senescence and many have been implicated in encoding enzymes involved in the metabolism of senescing tissues. Using the differential display technique, we identified a SAG in bean (Phaseolus vulgaris) leaf that was exclusively expressed during senescence and was designated senescence-associated receptor-like kinase (SARK). The deduced SARK polypeptide consists of a signal peptide, a leucine-rich repeat in the extracellular region, a single membrane-spanning domain, and the characteristic serine/threonine protein kinase domain. The mRNA level for SARK increased prior to the loss of chlorophyll and the decrease of chlorophylla/b-binding protein mRNA. Detached mature bean leaves, which senesce at an accelerated rate compared with leaves on intact plants, showed a similar temporal pattern of SARK message accumulation. Light and cytokinin, which delayed the initiation of leaf senescence, also delayed SARK gene expression; in contrast, darkness and ethylene, which accelerated senescence, advanced the initial appearance of the SARK transcript. SARK protein accumulation exhibited a temporal pattern similar to that of its mRNA. A possible role for SARK in the regulation of leaf senescence was considered.
Glutathione and Homoglutathione Synthetases of Legume Nodules. Cloning, Expression, and Subcellular Localization
Authors: Moran Jose F. , Iturbe-Ormaetxe Iñaki , Matamoros Manuel A. , Rubio Maria C. , Clemente Maria R. , Brewin Nicholas J. , Becana Manuel 
Published: July 2002

Abstract
The thiol tripeptides glutathione (GSH) and homoglutathione (hGSH) are very abundant in legume root nodules and their synthesis is catalyzed by the enzymes γ-glutamylcysteine synthetase (γECS), GSH synthetase (GSHS), and hGSH synthetase (hGSHS). As an essential step to elucidate the role of thiols in N2 fixation we have isolated cDNAs encoding the three enzymes and have quantified the transcripts in nodules. Assay of enzyme activities in highly purified nodule organelles revealed that γECS is localized in the plastids, hGSHS in the cytosol, and GSHS in the cytosol and mitochondria. These results are consistent with sequence analyses. Subcellular fractionation of nodules also showed that bacteroids contain high thiol concentrations and high specific γECS and GSHS activities. Results emphasize the role of nodule plastids in antioxidant protection and in control of thiol synthesis, and suggest that plastids may be important in the stress response of nodules. Overall, our results provide further evidence that thiol synthesis is critical for nodule functioning.
Active Retrotransposons Are a Common Feature of Grass Genomes
Authors: Vicient Carlos M. , Jääskeläinen Marko J. , Kalendar Ruslan , Schulman Alan H. 
Published: July 2002

Abstract
A large fraction of the genomes of grasses, members of the family Graminae, is composed of retrotransposons. These elements resemble animal retroviruses in their structure and possess a life cycle similar to theirs that includes transcription, translation, and integration of daughter copies. We have investigated if retrotransposons are generally transcribed in the grasses and other plants, and whether the various families of elements are translationally and integrationally active in multiple grass species. A systematic search of 7.8 × 105 publicly available expressed sequence tags from plants revealed widespread retrotransposon transcripts at a frequency of one in 1,000. Monocot retrotransposons found relatively more expressed sequence tags from non-source species than did those of dicots. Antibodies were raised to the capsid protein, GAG, ofBARE-1, a transcribed and translatedcopia-like retrotransposon of barley (Hordeum vulgare). These detected immunoreactive proteins of sizes identical to those of the BARE-1 GAG and polyprotein, respectively, in other species of the tribe Triticeae as well as in oats (Avena sativa) and rice (Oryza sativa). Retrotransposon-based markers showed integrational polymorphisms for BARE-1 in different subfamilies of the Graminae. The results suggest that grasses share families of transcriptionally, translationally, and integrationally active retrotransposons, enabling a comparative and integrative approach to understanding the life cycle of retrotransposons and their impact on the genome.
The High Level of Aluminum Resistance in Signalgrass Is Not Associated with Known Mechanisms of External Aluminum Detoxification in Root Apices
Authors: Wenzl Peter , Patiño Gloria M. , Chaves Alba L. , Mayer Jorge E. , Rao Idupulapati M. 
Published: July 2002

Abstract
Al resistance of signalgrass (Brachiaria decumbens Stapf cv Basilisk), a widely sown tropical forage grass, is outstanding compared with the closely related ruzigrass (Brachiaria ruziziensis Germain and Evrard cv Common) and Al-resistant genotypes of graminaceous crops such as wheat, triticale, and maize. Secretion of organic acids and phosphate by root apices and alkalinization of the apical rhizosphere are commonly believed to be important mechanisms of Al resistance. However, root apices of signalgrass secreted only moderately larger quantities of organic acids than did those of ruzigrass, and efflux from signalgrass apices was three to 30 times smaller than from apices of Al-resistant genotypes of buckwheat, maize, and wheat (all much more sensitive to Al than signalgrass). In the presence, but not absence, of Al, root apices of signalgrass alkalinized the rhizosphere more than did those of ruzigrass. The latter was associated with a shortening of the alkalinizing zone in Al-intoxicated apices of ruzigrass, indicating that differences in alkalinizing power were a consequence, not a cause of, differential Al resistance. These data indicate that the main mechanism of Al resistance in signalgrass does not involve external detoxification of Al. Therefore, highly effective resistance mechanisms based on different physiological strategies appear to operate in this species.
Evidence for Non-Circadian Light/Dark-Regulated Expression of Hsp70s in Spinach Leaves
Authors: Li Qin-Bao , Guy Charles L. 
Published: July 2002

AbstractExpression of six Hsp70s in spinach (Spinacia oleracea cv Longstanding Bloomsdale) leaves grown under isothermal conditions is regulated by a light/dark (L/D) mechanism distinctly different from the light-regulated mechanism for the chlorophyll a/b-binding protein (cab) or small subunit of ribulose-1,5-bisphosphate carboxylase oxygenase (rbcS). Subjecting entrained plants to two or three L/D cycles within a 24-h period resulted in an equal number of oscillations in expression for five out of six 70-kD heat shock proteins (Hsp70s). Three cycles appear to be the maximum, as shorter L/D treatments do not consistently increase the number of cycles in a 24-h period. The expression response of Hsp70s to L/D is overridden by heat shock. Protein disulfide isomerase, a second molecular chaperone of the endoplasmic reticulum, has an expression pattern in entrained plants that is similar to hsc70-2, the endoplasmic reticulum luminal Hsp70 binding protein. The parallel expression patterns for the various Hsp70s and protein disulfide isomerase indicate a likely general coordinate L/D regulation for molecular chaperones in plants. Multiple inductions in response to successive L/D treatments within a 24-h period in entrained plants for five of six Hsp70s support the conclusion that expression is not a consequence of circadian control, but instead is independently cued by non-circadian-mediated L/D signals where peak Hsp70 expression precedes the daily thermoperiod maximum.
Pollen Tubes of Nicotiana alata Express Two Genes from Different β-Glucan Synthase Families
Authors: Doblin Monika S. , De Melis Linda , Newbigin Ed , Bacic Antony , Read Steve M. 
Published: July 2002

Abstract
The walls deposited by growing pollen tubes contain two types of β-glucan, the (1,3)-β-glucan callose and the (1,4)-β-glucan cellulose, as well as various α-linked pectic polysaccharides. Pollen tubes of Nicotiana alata Link et Otto, an ornamental tobacco, were therefore used to identify genes potentially encoding catalytic subunits of the callose synthase and cellulose synthase enzymes. Reverse transcriptase-polymerase chain reactions (RT-PCR) with pollen-tube RNA and primers designed to conserved regions of bacterial and plant cellulose synthase (CesA) genes amplified a fragment that corresponded to an abundantly expressed cellulose-synthase-like gene named NaCslD1. A fragment from a true CesA gene (NaCesA1) was also amplified, but corresponding cDNAs could not be identified in a pollen-tube library, consistent with the very low level of expression of the NaCesA1 gene. RT-PCR with pollen-tube RNA and primers designed to regions conserved between the fungalFKS genes [that encode (1,3)-β-glucan synthases] and their presumed plant homologs (the Gsl or glucan-synthase-like genes) amplified a fragment that corresponded to an abundantly expressed gene named NaGsl1. A secondGsl gene detected by RT-PCR (NaGsl2) was expressed at low levels in immature floral organs. The structure of full-length cDNAs of NaCslD1, NaCesA1, and NaGsl1 are presented. Both NaCslD1and NaGsl1 are predominantly expressed in the male gametophyte (developing and mature pollen and growing pollen tubes), and we propose that they encode the catalytic subunits of two β-glucan synthases involved in pollen-tube wall synthesis. Different β-glucans deposited in one cell type may therefore be synthesized by enzymes from different gene families.
Elongation of the BH8 β‐hairpin peptide: Electrostatic interactions in β‐hairpin formation and stability
Authors: Ramírez‐Alvarado Marina , Blanco Francisco J. , Serrano Luis 
Published: July 2002

AbstractAn elongated version of the de novo designed β‐hairpin peptide, BH8, has allowed us to gain insight into the role of electrostatic interactions in β‐hairpin stability. A Lys–Glu electrostatic pair has been introduced by adding a residue at the beginning and at the end of the N‐terminal and C‐terminal strands, respectively, of the β‐hairpin structure, in both orientations. The two resulting peptides and controls having Ala residues at these positions and different combinations of Ala with Lys, or Glu residues, have been analyzed by nuclear magnetic resonance (NMR), under different pH and ionic strength conditions. All of the NMR parameters, in particular the conformational shift analysis of Cα protons and the coupling constants, 3JHNα, correlate well and the population estimates are in reasonable agreement among the different methods used. In the most structured peptides, we find an extension of the β‐hairpin structure comprising the two extra residues. Analysis of the pH and salt dependence shows that ionic pairs contribute to β‐hairpin stability. The interaction is electrostatic in nature and can be screened by salt. There is also an important salt‐independent contribution of negatively charged groups to the stability of this family of β‐hairpin peptides.
Numerical Simulation of Real-Gas Flow in a Supersonic Turbine Nozzle
Ring
Authors: Hoffren J. , Talonpoika T. , Larjola J. , Siikonen T. 
Published: July 2002

Abstract
In small Rankine cycle power plants, it is advantageous to use organic media as the working fluid. A low-cost single-stage turbine design together with the high molecular weight of the fluid leads to high Mach numbers in the turbine. Turbine efficiency can be improved significantly by using an iterative design procedure based on an accurate CFD simulation of the flow. For this purpose, an existing Navier-Stokes solver is tailored for real gas, because the expansion of an organic fluid cannot be described with ideal gas equations. The proposed simulation method is applied for the calculation of supersonic flow in a turbine stator. The main contribution of the paper is to demonstrate how a typical ideal-gas CFD code can be adapted for real gases in a very general, fast, and robust manner.
Anisotropic Yield Locus Evolution During Cold Pilgering of Titanium
Alloy Tubing
Authors: Davies Richard W. , Khaleel Mohammad A. , Kinsel William C. , Zbib Hussein M. 
Published: July 2002

Abstract
The cold pilger metal forming technique is known to produce round titanium alloy tubing with mechanical properties that may be significantly anisotropic. These mechanical properties are of interest to both the manufacturers and consumers for defining initial manufacturing limitations and defining the final product design limitations. This study focuses on experimentally characterizing the yield locus development of Ti-3Al-2.5V seamless tubing during cold pilgering and a subsequent thermal stress relieving process. The materials are experimentally characterized using a biaxial testing apparatus, which subjects the specimen tubes to combined axial load and internal pressure. The Hill yield criterion is subsequently fit to the experimental results producing continuous yield loci. Each specimen is also experimentally characterized using X-ray diffraction to gain insight into the material textures that accompany the macroscopic properties. All work is focused on one particular pilger pass at two different production rates. A second experimental variable is introduced to the study by using two significantly different input materials, as characterized by X-ray diffraction. This study also investigates the nature of the plastic deformation of the tubing developed during cold pilgering via finite element analysis and discusses the relationship between the finite element predictions and the mechanical anisotropy.
Evidence of anomalous behavior in low-n-type mercury cadmium telluride induced by extended defects
Authors: Pelliciari B. , Destefanis G. L. , Di Cioccio L. 
Published: July 2002

Suitable improvements of our liquid phase epitaxy (LPE) growth process enable us to obtain excellent quality p-type as-grown mercury cadmium telluride (MCT) epilayers, well adapted to high-performance photovoltaic (PV) detector technology. Although our technology only needs undoped p-type MCT as starting material, we also convert a lot of these epilayers to n type to check their electrical properties in view of two fundamental problems: anomalies of electrical behavior and residual doping level. After n-type annealing, most of our LPE layers have a classical behavior versus temperature even under a high magnetic field value of 10 000 G: at 77 K, values of n77d =2×1014 cm−3 and μ77 =105 cm2  V−1  s−1 and at 27 K n27d =2×1014 cm−3 and μ27 =2 to 3×105 cm2 V−1  s−1 are routinely obtained, for a cutoff wavelength of 6.3 μm (as given by IR transmission at room temperature); this corresponds to a cutoff wavelength of 10.6 μm at 77 K, as measured on our PV diodes.
Transmission electron microscopy (TEM) observations show that these layers are defect-free and this is confirmed by x-ray topography which shows only the misfit dislocation pattern. However, some samples have an anomalous behavior featured by a ‘‘kink’’ on the mobility curve between 100 and 77 K, the nd value being in the low-1014 range. TEM observations show in this case the presence of dislocations, the density of which is directly correlated to a more or less significant kink on the mobility curve; also, the aspect of the x-ray topography changes from a sharp misfit structure (low density of loops) to a mixed structure (higher density of loops). If this density of loops is still increased, the x-ray topography becomes hazy and the Hall-effect measurement indicates the epilayer to be p type even after an n-type annealing. These loops are assumed to generate doping microinhomogeneities responsible for anomalous Hall-effect behavior. So, extended defects have to be avoided to achieve high-quality MCT material; a way to reach this goal is to grow buffered structures, the electrical properties of which are presented together with TEM observations.
Inhibition of Cyclin-Dependent Kinase Activity and Induction of Apoptosis by Preussin in Human Tumor Cells
Authors: Achenbach Tatjana V. , Slater Emily P. , Brummerhop Harm , Bach Thorsten , Müller Rolf 
Published: July 2002

ABSTRACTIn this paper, we report that (+)-preussin, a pyrrolidinol alkaloid originally identified as an antifungal agent, has growth-inhibitory and cytotoxic effects on human cancer cells. Preussin was found to be a potent inhibitor of cyclin E kinase (CDK2-cyclin E) in vitro (50% inhibitory concentration; ∼500 nM) and to inhibit cell cycle progression into S phase. In agreement with these findings, the level of the cyclin-dependent kinase inhibitor p27KIP-1is increased in response to preussin treatment while the expression of both cyclin A and the transcription factor E2F-1 is down-regulated. Preussin also induces programmed cell death (apoptosis), which requires caspase activation and involves the release of cytochromecfrom mitochondria. This induction of apoptosis is not blocked by high levels of Bcl-2, which usually confers resistance to chemotherapeutic agents. Taken together, our data indicate that preussin could be a promising lead compound for the development of a new class of potent antitumor drugs.
Regional Prophylaxis with Teicoplanin in Monolateral or Bilateral Total Knee Replacement: an Open Study
Authors: de Lalla Fausto , Viola Renato , Pellizzer Giampietro , Lazzarini Luca , Tramarin Andrea , Fabris Paolo 
Published: July 2002

ABSTRACT

From January 1991 to June 1997, patients undergoing primary elective monolateral or bilateral total knee replacement (TKR) were consecutively enrolled in a prospective, open clinical study on the efficacy and safety of regional prophylaxis with teicoplanin (TEC). Those scheduled for monolateral TKR (115 patients) received 400 mg of TEC in 100 ml of saline as a 5-min infusion into a foot vein of the leg to be operated on immediately after the tourniquet was inflated to 400 mm Hg (ca. 50 kPa). For patients undergoing bilateral surgery (45 patients), regional administration of TEC was also repeated for the second knee operation. Follow-up ranged from a minimum of 2 years to 8 years. None of the patients experienced local or systemic adverse effects following regional administration of TEC. In the immediate postoperative and 2-year follow-up periods, only one superficial infection of the primary site attributable to intraoperative contamination (prophylaxis failure) out of the 205 prostheses implanted was observed. Deep infections involving the prosthesis did not occur. Infectious complications at distant sites were observed in nine cases (urinary tract infection due to
Escherichia coli
in eight cases, and
Salmonella enteritidis
gastroenteritis in one case) in the immediate postoperative period; they all were rapidly cured after antibiotic treatment. A delayed prosthetic infection, related to hematogenous spread of the etiological agent and therefore not considered a prophylactic failure, was observed in a patient who had undergone TKR 5 years before. Regional administration of TEC in monolateral and bilateral TKR appears to be a safe and valuable prophylactic technique.