bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Characterization of Plant Ubiquitin-Conjugating Enzymes Belonging to the UbcP4/E2-C/UBCx/UbcH10 Gene Family
Authors: Criqui Marie Claire , de Almeida Engler Janice , Camasses Alain , Capron Arnaud , Parmentier Yves , Inzé Dirk , Genschik Pascal 
Published: November 2002

AbstractThe anaphase promoting complex or cyclosome is the ubiquitin-ligase that targets destruction box-containing proteins for proteolysis during the cell cycle. Anaphase promoting complex or cyclosome and its activator (the fizzy and fizzy-related) proteins work together with ubiquitin-conjugating enzymes (UBCs) (E2s). One class of E2s (called E2-C) seems specifically involved in cyclin B1 degradation. Although it has recently been shown that mammalian E2-C is regulated at the protein level during the cell cycle, not much is known concerning the expression of these genes. Arabidopsis encodes two genes belonging to the E2-C gene family (called UBC19 andUBC20). We found that UBC19 is able to complement fission yeast (Schizosaccharomyces pombe)UbcP4-140 mutant, indicating that the plant protein can functionally replace its yeast ortholog for protein degradation during mitosis. In situ hybridization experiments were performed to study the expression of the E2-C genes in various tissues of plants. Their transcripts were always, but not exclusively, found in tissues active for cell division. Thus, the UBC19/20 E2s may have a key function during cell cycle, but may also be involved in ubiquitylation reactions occurring during differentiation and/or in differentiated cells. Finally, we showed that a translational fusion protein between UBC19 and green fluorescent protein localized both in the cytosol and the nucleus in stable transformed tobacco (Nicotiana tabacumcv Bright Yellow 2) cells.
Cesarean section as a cause of chronic pelvic pain
Authors: Almeida E.C.S , Nogueira A.A , Candido dos Reis F.J , Rosa e Silva J.C 
Published: November 2002

AbstractObjective: To determine if the history of cesarean section was associated with chronic pelvic pain, independent of the presence of other conditions such as pelvic adhesions, endometriosis, sequelae of pelvic inflammatory disease, leiomyoma and pelvic varices. Methods: Retrospective case–control study conducted on 199 patients consecutively admitted from January 1998 to January 2000, 116 of them submitted to laparoscopy for the diagnosis of chronic pelvic pain and 83 asymptomatic patients submitted to tubal ligation by laparoscopy. A logistic regression analysis was used to verify the association between chronic pelvic pain and the history of previous cesarean section. Results: In women with chronic pelvic pain, a history of cesarean section was observed in 67.2% of cases, adhesions in 51.7%, endometriosis in 33.6%, sequelae of pelvic inflammatory disease in 31.9%, leiomyoma in 6.9% and pelvic varices in 11.2%. In asymptomatic women, a history of cesarean section was observed in 38.5%, adhesions in 24.1%, endometriosis in 9.6%, sequelae of pelvic inflammatory disease in 4.8%, leiomyoma in 7.2% and pelvic varices in 3.6%. In a logistic model, chronic pelvic pain was associated with a history of cesarean section (O.R.=3.7), as well as with endometriosis (O.R.=8.5), sequelae of pelvic inflammatory disease (O.R.=10.5). Conclusions: In the present study cesarean section was associated with chronic pelvic pain. This fact may be the cause of a public health problem in the coming years, due to the raised rates of cesarean section in Brazilian women.
Radiographic evaluation of the relationship between the projection of genial tubercles and the lingual foramen.
Authors: Baldissera E Z , Silveira H D 
Published: November 2002

OBJECTIVE Reports in specialized literature present divergent opinions about what corresponds to the radiopaque areas surrounding the lingual foramen. The purpose of this study is to radiographically evaluate whether these areas correspond to the genial tubercles. METHODS We selected 15 dry mandibles and obtained images of the lower incisors region by computed tomography (CT) and periapical radiography at vertical angles of -10 degrees, -20 degrees and -30 degrees. For periapical radiography, the genial tubercles and the lingual foramen were marked with stainless steel wire to demonstrate the relationship between them. RESULTS The images on periapical radiographs, as well as on CT scans of the region, showed that there is no relationship between radiopaque areas around the lingual foramen and the genial tubercles. CONCLUSION The radiopaque area surrounding the lingual foramen corresponds to the walls of a nutrient canal and not to the genial tubercles. Therefore, we recommend that the information about this anatomical landmark be reviewed in specialized literature.
The Combined Effect of Drought Stress and Heat Shock on Gene Expression in Tobacco
Authors: Rizhsky Ludmila , Liang Hongjian , Mittler Ron 
Published: November 2002

Abstract
In nature, plants encounter a combination of environmental conditions that may include stresses such as drought or heat shock. Although drought and heat shock have been extensively studied, little is known about how their combination affect plants. We used cDNA arrays, coupled with physiological measurements, to study the effect of drought and heat shock on tobacco (Nicotiana tabacum) plants. A combination of drought and heat shock resulted in the closure of stomata, suppression of photosynthesis, enhancement of respiration, and increased leaf temperature. Some transcripts induced during drought, e.g. those encoding dehydrin, catalase, and glycolate oxidase, and some transcripts induced during heat shock, e.g. thioredoxin peroxidase, and ascorbate peroxidase, were suppressed during a combination of drought and heat shock. In contrast, the expression of other transcripts, including alternative oxidase, glutathione peroxidase, phenylalanine ammonia lyase, pathogenesis-related proteins, a WRKY transcription factor, and an ethylene response transcriptional co-activator, was specifically induced during a combination of drought and heat shock. Photosynthetic genes were suppressed, whereas transcripts encoding some glycolysis and pentose phosphate pathway enzymes were induced, suggesting the utilization of sugars through these pathways during stress. Our results demonstrate that the response of plants to a combination of drought and heat shock, similar to the conditions in many natural environments, is different from the response of plants to each of these stresses applied individually, as typically tested in the laboratory. This response was also different from the response of plants to other stresses such as cold, salt, or pathogen attack. Therefore, improving stress tolerance of plants and crops may require a reevaluation, taking into account the effect of multiple stresses on plant metabolism and defense.
Alternate Energy-Dependent Pathways for the Vacuolar Uptake of Glucose and Glutathione Conjugates
Authors: Bartholomew Dolores M. , Van Dyk Drew E. , Lau Sze-Mei Cindy , O'Keefe Daniel P. , Rea Philip A. , Viitanen Paul V. 
Published: November 2002

Abstract
Through the development and application of a liquid chromatography-mass spectrometry-based procedure for measuring the transport of complex organic molecules by vacuolar membrane vesicles in vitro, it is shown that the mechanism of uptake of sulfonylurea herbicides is determined by the ligand, glucose, or glutathione, to which the herbicide is conjugated. ATP-dependent accumulation of glucosylated chlorsulfuron by vacuolar membrane vesicles purified from red beet (Beta vulgaris) storage root approximates Michaelis-Menten kinetics and is strongly inhibited by agents that collapse or prevent the formation of a transmembrane H+gradient, but is completely insensitive to the phosphoryl transition state analog, vanadate. In contrast, ATP-dependent accumulation of the glutathione conjugate of a chlorsulfuron analog, chlorimuron-ethyl, is incompletely inhibited by agents that dissipate the transmembrane H+ gradient but completely abolished by vanadate. In both cases, however, conjugation is essential for net uptake because neither of the unconjugated parent compounds are accumulated under energized or nonenergized conditions. That the attachment of glucose to two naturally occurring phenylpropanoids, p-hydroxycinnamic acid and p-hydroxybenzoic acid via aromatic hydroxyl groups, targets these compounds to the functional equivalent of the transporter responsible for chlorsulfuron-glucoside transport, confirms the general applicability of the H+ gradient dependence of glucoside uptake. It is concluded that H+gradient-dependent, vanadate-insensitive glucoside uptake is mediated by an H+ antiporter, whereas vanadate-sensitive glutathione conjugate uptake is mediated by an ATP-binding cassette transporter. In so doing, it is established that liquid chromatography-mass spectrometry affords a versatile high-sensitivity, high-fidelity technique for studies of the transport of complex organic molecules whose synthesis as radiolabeled derivatives is laborious and/or prohibitively expensive.
Interactions of Nitrate and CO2 Enrichment on Growth, Carbohydrates, and Rubisco in Arabidopsis Starch Mutants. Significance of Starch and Hexose
Authors: Sun Jindong , Gibson Kelly M. , Kiirats Olavi , Okita Thomas W. , Edwards Gerald E. 
Published: November 2002

Abstract
Wild-type (wt) Arabidopsis plants, the starch-deficient mutant TL46, and the near-starchless mutant TL25 were grown in hydroponics under two levels of nitrate, 0.2 versus 6 mm, and two levels of CO2, 35 versus 100 Pa. Growth (fresh weight and leaf area basis) was highest in wt plants, lower in TL46, and much lower in TL25 plants under a given treatment. It is surprising that the inability to synthesize starch restricted leaf area development under both low N (NL) and high N (NH). For each genotype, the order of greatest growth among the four treatments was high CO2/NH &gt; low CO2/NH, &gt; high CO2/NL, which was similar to low CO2/NL. Under high CO2/NL, wt and TL46 plants retained considerable starch in leaves at the end of the night period, and TL25 accumulated large amounts of soluble sugars, indicative of N-limited restraints on utilization of photosynthates. The lowest ribulose-1,5-bisphosphate carboxylase/oxygenase per leaf area was in plants grown under high CO2/NL. When N supply is limited, the increase in soluble sugars, particularly in the starch mutants, apparently accentuates the feedback and down-regulation of ribulose-1,5-bisphosphate carboxylase/oxygenase, resulting in greater reduction of growth. With an adequate supply of N, growth is limited in the starch mutants due to insufficient carbohydrate reserves during the dark period. A combination of limited N and a limited capacity to synthesize starch, which restrict the capacity to use photosynthate, and high CO2, which increases the potential to produce photosynthate, provides conditions for strong down-regulation of photosynthesis.
Two Putative BIN2 Substrates Are Nuclear Components of Brassinosteroid Signaling
Authors: Zhao Jun , Peng Peng , Schmitz Robert J. , Decker Adria D. , Tax Frans E. , Li Jianming 
Published: November 2002

AbstractGSK3 is a highly conserved kinase that negatively regulates many cellular processes by phosphorylating a variety of protein substrates. BIN2 is a GSK3-like kinase in Arabidopsis that functions as a negative regulator of brassinosteroid (BR) signaling. It was proposed that BR signals, perceived by a membrane BR receptor complex that contains the leucine (Leu)-rich repeat receptor-like kinase BRI1, inactivate BIN2 to relieve its inhibitory effect on unknown downstream BR-signaling components. Using a yeast (Saccharomyces cerevisiae) two-hybrid approach, we discovered a potential BIN2 substrate that is identical to a recently identified BR-signaling protein, BES1. BES1 and its closest homolog, BZR1, which was also uncovered as a potential BR-signaling protein, display specific interactions with BIN2 in yeast. Both BES1 and BZR1 contain many copies of a conserved GSK3 phosphorylation site and can be phosphorylated by BIN2 in vitro via a novel GSK3 phosphorylation mechanism that is independent of a priming phosphorylation or a scaffold protein. Five independentbes1 alleles containing the same proline-233-Leu mutation were identified as semidominant suppressors of two differentbri1 mutations. Over-expression of the wild-typeBZR1 gene partially complementedbin2/+ mutants and resulted in aBRI1 overexpression phenotype in aBIN2 + background, whereas overexpression of a mutated BZR1 gene containing the corresponding proline-234-Leu mutation rescued a weakbri1 mutation and led to a bes1-like phenotype. Confocal microscopic analysis indicated that both BES1 and BZR1 proteins were mainly localized in the nucleus. We propose that BES1/BZR1 are two nuclear components of BR signaling that are negatively regulated by BIN2 through a phosphorylation-initiated process.
Design, syntheses, and evaluation of 2,3‐diphenylcycloprop‐2‐en‐1‐ones and oxime derivatives as potential cyclooxygenase‐2 (COX‐2) inhibitors with analgesic‐antiinflammatory activity
Authors: Li Huiying , Praveen Rao P.N. , Habeeb Amgad G. , Knaus Edward E. 
Published: November 2002

AbstractA group of 2,3‐diphenylcycloprop‐2‐enes having a variety of substituents at the para‐position of the C‐2 phenyl ring (H, F), and C‐3 phenyl ring (H, F, SMe, SOMe, SO2Me), in conjunction with either a C‐1 carbonyl, oxime, oxime acetate, benzoyl hydrazone, or hydrogen substituent were synthesized for in vivo evaluation as analgesic and antiinflammatory (AI) agents, and as potential selective cyclooxygenase‐2 (COX‐2) inhibitors. This group of cycloprop‐2‐ene compounds exhibited significant analgesic activity, since 4% NaCl‐induced abdominal constriction was reduced by 43–90% at 30 min, and 41–100% at 60 min, after drug administration relative to the reference drugs aspirin and celecoxib (58% and 32% inhibition at 30 min after drug administration) for a 50 mg/kg intraperitoneal dose. AI activities, determined using the carrageenan‐induced rat paw edema assay, showed that this class of cycloprop‐2‐ene compounds exhibited AI activities in the inactive‐to‐modest activity range (0–26% inhibition) for a 50 mg/kg oral dose. The AI potency order for a group of 2,3‐diphenylcycloprop‐2‐enes with respect to the C‐1 substituent was oxime>hydrogen>carbonyl>benzoyl hydrazone. 2,3‐Diphenylcycloprop‐2‐en‐1‐one oxime (20) was the most active AI agent, inducing a 26% reduction in inflammation, relative to the reference drugs ibuprofen and celecoxib, which showed 52% and 58% reductions in inflammation, at 5 h after drug administration. In vitro COX‐1 and COX‐2 inhibition studies showed that 2,3‐diphenylcycloprop‐2‐en‐1‐one oxime (20) is a selective COX‐2 inhibitor (COX‐1 IC50>100 μM; COX‐2 IC50=2.94 μM; COX‐2 selectivity index>34). A molecular modeling study that docked the oxime (20) in the active site of the human COX‐2 isozyme showed that it binds in the vicinity of the mouth of the COX‐2 binding site with the O‐atom of the oxime (=N–OH) moiety separated from the NH2 group of Arg120 by about 3.65 Å. This orientation of the oxime compound (20) in the COX‐2 binding site could be due to a potentially strong ionic interaction between the =NOH oxime moiety and the guanidinium moiety of Arg120. Drug Dev. Res. 57:6–17, 2002. © 2002 Wiley‐Liss, Inc.
Markers of endothelial function in pediatric stem cell transplantation for acute leukemia
Authors: Luzzatto Guido , Cella Giuseppe , Messina Chiara , Randi Maria Luigia , Sbarai Alessandra , Zanesco Luigi 
Published: November 2002

AbstractBackgroundEndothelial cells and leukocytes intimately interact in inflammation and coagulation processes, so that dysregulation of their function may lead to both cellular damage and thrombosis, which may occur as complications of bone marrow transplantation (BMT). Partially conflicting evidence about endothelial markers and their relationships with clinical complications after BMT has been reported in the literature. Since almost all studies were carried out in adults, we evaluated some recent available markers of endothelial cell function in pediatric patients undergoing stem cell transplantation (SCT) for acute leukemia.ProcedureWe studied the variation in circulating serum endothelial‐selectin (ES), leukocyte‐selectin (LS), thrombomodulin (TM), von Willebrand factor (vWF), nitrate + nitrite (NO2−/NO3−), endothelin‐1 (EN), and tissue factor (TF) in 21 pediatric patients undergoing SCT for acute leukemia.ResultsES and LS significantly lowered following SCT and returned to pre‐SCT levels 4 weeks after the procedure. NO2−/NO3− markedly increased following SCT. Also, TM and vWF increased, although such changes did not reach statistical significance. EN and TF did not appreciably change. A strong correlation was observed between white blood cell (WBC) count and both ES and LS, as well as between such selectins. TM significantly correlated with both selectins and NO2−/NO3−. The pre‐conditioning levels of TM and vWF in patients undergoing major complications, considered altogether, were significantly lower and higher, respectively, than in uncomplicated patients. NO2−/NO3− levels 3 and 4 weeks post‐SCT were significantly lower in patients suffering from veno occlusive disease. Both selectins were significantly higher in allo‐ than in auto‐transplanted patients 4 weeks after SCT.ConclusionsOur data support the hypothesis of severe endothelial damage after conditioning and SCT, particularly allogeneic. However, the increase in TM, which has strong anticoagulant properties, and metabolites of NO, involved also in protective actions, may reflect regeneration of the anti‐thrombotic endothelial function. This could take place after transitory functional impairment, rather than pure endothelial damage. Med Pediatr Oncol 2003;40:9–12, © 2003 Wiley‐Liss, Inc.
Cavitation of polyethylene during extrusion processing instabilities
Authors: Son Younggon , Migler Kalman B. 
Published: November 2002

AbstractWe present observations of cavitation that occur inside a capillary die during extrusion of polyethylene. This phenomenon was observed over the last 1.5 mm of the capillary tube immediately upstream of the exit. We observed spontaneous formation of voids near the wall that grew to a typical length and width of 150 μm, and then shrank and disappeared over a time frame of approximately 20 ms. From velocity measurements of these structures, we concluded that their width in the radial direction was smaller than in the axial and lateral directions, and they were near the wall. The shape of the cavities was highly irregular. We assessed the roles of extensional stress and shear stress at the exit region and concluded that they were not the direct cause of cavitation. Rather, cavitation occurs in conjunction with an upstream rupture of the polymer that occurs in the contraction region leading into the capillary tube (gross melt fracture). We argue that the exit region does, however, serve as the initiation point of the cavitation because of a combination of the reduced pressure and extensional stress. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2791–2799, 2002
Microviscosity in poly(ethylene oxide)‐polypropylene oxide‐poly(ethylene oxide) block copolymers probed by fluorescence depolarization kinetics
Authors: Jeon Sangmin , Granick Steve , Kwon Kwan‐Wook , Char Kookheon 
Published: November 2002

AbstractTriblock copolymers [poly(ethylene oxide) (PEO) and polypropylene oxide (PPO)], Pluronic F127 with 100 PEO blocks on each end, and 65 blocks of PPO in the center were examined in aqueous solution. The “sol” and “gel” phase diagram was determined as a function of concentration and temperature. For further study, the concentration was fixed at 20 wt %, and the temperature dependence of the dynamic viscosity differed from the temperature dependence of fluorescence emission spectra and the microviscosity probed by the fluorescence depolarization kinetics of rhodamine 123 dye, which was dissolved in the continuous hydrophilic phase. The depolarization measurements used single‐photon counting after two‐photon excitation with a Ti‐sapphire femtosecond laser. Although the viscoelastic modulus increased by an order of magnitude when the sol‐to‐gel transition was crossed, the microviscosity of the hydrophilic continuous medium showed only minor changes. At different temperatures the fluorescence lifetime was the same with a single‐exponential time constant, but the fluorescence depolarization displayed a double‐exponential decay. After comparison with fluorescence depolarization of the dye in PPO melt and PEO whose molecular weight and aqueous concentrations were varied, the relative proportions of faster and slower components of the fluorescence depolarization were tentatively attributed to varying ratios of the dye in free solution and associated with micelles. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2883–2888, 2002
Structure and properties of polyamide‐6/vermiculite nanocomposites prepared by direct melt compounding
Authors: Tjong S. C. , Meng Y. Z. , Xu Y. 
Published: November 2002

AbstractPolyamide‐6 (PA6)/vermiculite nanocomposites were fabricated through the direct melt compounding of maleic anhydride‐modified vermiculite (MAV) with PA6 in a twin‐screw extruder followed by injection molding. The structure and morphology of the nanocomposites were determined by X‐ray diffraction and scanning and transmission electron microscopy techniques. The results revealed the formation of intercalated and exfoliated vermiculite platelets in the PA6 matrix. Tensile measurement showed that the tensile modulus and strength of the nanocomposites tended to increase with increasing vermiculite content. The thermal properties of the nanocomposites were determined by dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetry measurements. The storage modulus of the PA6–MAV nanocomposites increased to almost twice that of the neat PA6. The thermal stability of the nanocomposites increased dramatically, and this was associated with the addition of vermiculite. The effect of the addition of maleic anhydride on the formation of the PA6–vermiculite nanocomposites was examined. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2860–2870, 2002
Surface modification of ethylene‐co‐tetrafluoroethylene films by remote plasmas
Authors: Inagaki Norihiro , Narushima Kazuo , Lim Sang Kyoo , Park Yong Woo , Ikeda Yousuke 
Published: November 2002

AbstractThe surface modifications of ethylene‐co‐tetrafluoroethylene (ETFE) surfaces by six plasmas (direct H2, Ar, and O2 plasmas and remote H2, Ar, and O2 plasmas) were investigated with two questions in mind: (1) what plasma could effectively modify ETFE surfaces and (2) which of the CF2CF2 and CH2CH2 components in ETFE was selectively modified? The plasma exposure led to a weight loss from the ETFE surfaces and changes in the chemical composition on ETFE surfaces. The weight‐loss rate showed a strong dependence on what plasma was used for the modification. The remote H2 plasma led to the lowest rate of weight loss in the six plasma exposures, and the direct O2 plasma led to the highest rate of weight loss. During exposure to the plasmas, defluorination occurred, and two new C1s components [CH2CHFCH2 and CH2CH(OR)CFx, and CH2CHFCF2, CH2C(O)CFx, and CFxC(O)O] were formed on the modified ETFE surfaces. Defluorination was strongly influenced by what plasma was used for the modification. The remote H2 and Ar plasmas showed high defluorinations of 55 and 51%, respectively. The remote O2 plasma showed a low defluorination of only 25%. Conclusively, the remote H2 and Ar plasma exposure effectively modified ETFE surfaces. With the exposure of these surfaces to the remote H2 plasma, the CF2CF2 component was predominantly modified, rather than the CH2CH2 component. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2871–2882, 2002