bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytochrome P450CYP710AEncodes the Sterol C-22 Desaturase inArabidopsisand Tomato
Authors: Morikawa Tomomi , Mizutani Masaharu , Aoki Nozomu , Watanabe Bunta , Saga Hirohisa , Saito Shigeki , Oikawa Akira , Suzuki Hideyuki , Sakurai Nozomu , Shibata Daisuke , Wadano Akira , Sakata Kanzo , Ohta Daisaku 
Published: March 2006

AbstractΔ22-Unsaturated sterols, containing a double bond at the C-22 position in the side chain, occur specifically in fungi and plants. Here, we describe the identification and characterization of cytochrome P450s belonging to the CYP710A family as the plant C-22 desaturase. Recombinant proteins of CYP710A1 and CYP710A2 from Arabidopsis thaliana and CYP710A11 from tomato (Lycopersicon esculentum) were expressed using a baculovirus/insect system. The Arabidopsis CYP710A1 and tomato CYP710A11 proteins exhibited C-22 desaturase activity with β-sitosterol to produce stigmasterol (CYP710A1, K m = 1.0 μM and kinetic constant [k cat] = 0.53 min−1; CYP710A11, K m = 3.7 μM and k cat = 10 min−1). In Arabidopsis transgenic lines with CYP710A1 and CYP710A11 overexpression, stigmasterol levels increased by 6- to 32-fold. Arabidopsis CYP710A2 was able to produce brassicasterol and stigmasterol from 24-epi-campesterol and β-sitosterol, respectively. Sterol profiling analyses for CYP710A2 overexpression and a T-DNA insertion event into CYP710A2 clearly demonstrated in planta that CYP710A2 was responsible for both brassicasterol and stigmasterol production. Semiquantitative PCR analyses and promoter:β-glucuronidase transgenic approaches indicated strict tissue/organ-specific regulation for each CYP710A gene, implicating differential tissue distributions of the Δ22-unsaturated sterols in Arabidopsis. Our results support the possibility that the CYP710 family may encode P450s of sterol C-22 desaturases in different organisms.
Calcium-Dependent Protein Kinase Isoforms inPetuniaHave Distinct Functions in Pollen Tube Growth, Including Regulating Polarity
Authors: Yoon Gyeong Mee , Dowd Peter E. , Gilroy Simon , McCubbin Andrew G. 
Published: March 2006

AbstractCalcium is a key regulator of pollen tube growth, but little is known concerning the downstream components of the signaling pathways involved. We identified two pollen-expressed calmodulin-like domain protein kinases from Petunia inflata, CALMODULIN-LIKE DOMAIN PROTEIN KINASE1 (Pi CDPK1) and Pi CDPK2. Transient overexpression or expression of catalytically modified Pi CDPK1 disrupted pollen tube growth polarity, whereas expression of Pi CDPK2 constructs inhibited tube growth but not polarity. Pi CDPK1 exhibited plasma membrane localization most likely mediated by acylation, and we present evidence that suggests this localization is critical to the biological function of this kinase. Pi CDPK2 substantially localized to as yet unidentified internal membrane compartments, and this localization was again, at least partially, mediated by acylation. In contrast with Pi CDPK1, altering the localization of Pi CDPK2 did not noticeably alter the effect of overexpressing this isoform on pollen tube growth. Ca2+ requirements for Pi CDPK1 activation correlated closely with Ca2+ concentrations measured in the growth zone at the pollen tube apex. Interestingly, loss of polarity associated with overexpression of Pi CDPK1 was associated with elevated cytosolic Ca2+ throughout the bulging tube tip, suggesting that Pi CDPK1 may participate in maintaining Ca2+ homeostasis. These results are discussed in relation to previous models for Ca2+ regulation of pollen tube growth.
LOW PSII ACCUMULATION1 Is Involved in Efficient Assembly of Photosystem II inArabidopsis thaliana
Authors: Peng Lianwei , Ma Jinfang , Chi Wei , Guo Jinkui , Zhu Shuyong , Lu Qingtao , Lu Congming , Zhang Lixin 
Published: March 2006

AbstractTo gain insight into the processes involved in photosystem II (PSII) biogenesis and maintenance, we characterized the low psii accumulation1 (lpa1) mutant of Arabidopsis thaliana, which generally accumulates lower than wild-type levels of the PSII complex. In vivo protein labeling experiments showed that synthesis of the D1 and D2 proteins was greatly reduced in the lpa1 mutant, while other plastid-encoded proteins were translated at rates similar to the wild type. In addition, turnover rates of the PSII core proteins CP47, CP43, D1, and D2 were higher in lpa1 than in wild-type plants. The newly synthesized PSII proteins were assembled into functional protein complexes, but the assembly was less efficient in the mutant. LPA1 encodes a chloroplast protein that contains two tetratricopeptide repeat domains and is an intrinsic membrane protein but not an integral subunit of PSII. Yeast two-hybrid studies revealed that LPA1 interacts with D1 but not with D2, cytochrome b6, or Alb3. Thus, LPA1 appears to be an integral membrane chaperone that is required for efficient PSII assembly, probably through direct interaction with the PSII reaction center protein D1.
The Structure of Rauvolfia serpentina Strictosidine Synthase Is a Novel Six-Bladed β-Propeller Fold in Plant Proteins
Authors: Ma Xueyan , Panjikar Santosh , Koepke Juergen , Loris Elke , Stöckigt Joachim 
Published: March 2006

Abstract
The enzyme strictosidine synthase (STR1) from the Indian medicinal plant Rauvolfia serpentina is of primary importance for the biosynthetic pathway of the indole alkaloid ajmaline. Moreover, STR1 initiates all biosynthetic pathways leading to the entire monoterpenoid indole alkaloid family representing an enormous structural variety of ∼2000 compounds in higher plants. The crystal structures of STR1 in complex with its natural substrates tryptamine and secologanin provide structural understanding of the observed substrate preference and identify residues lining the active site surface that contact the substrates. STR1 catalyzes a Pictet-Spengler–type reaction and represents a novel six-bladed β-propeller fold in plant proteins. Structure-based sequence alignment revealed a common repetitive sequence motif (three hydrophobic residues are followed by a small residue and a hydrophilic residue), indicating a possible evolutionary relationship between STR1 and several sequence-unrelated six-bladed β-propeller structures. Structural analysis and site-directed mutagenesis experiments demonstrate the essential role of Glu-309 in catalysis. The data will aid in deciphering the details of the reaction mechanism of STR1 as well as other members of this enzyme family.
Selective Mobility and Sensitivity to SNAREs Is Exhibited by theArabidopsisKAT1 K+ Channel at the Plasma Membrane
Authors: Sutter Jens-Uwe , Campanoni Prisca , Tyrrell Matthew , Blatt Michael R. 
Published: March 2006

AbstractRecent findings indicate that proteins in the SNARE superfamily are essential for cell signaling, in addition to facilitating vesicle traffic in plant cell homeostasis, growth, and development. We previously identified SNAREs SYP121/Syr1 from tobacco (Nicotiana tabacum) and the Arabidopsis thaliana homolog SYP121 associated with abscisic acid and drought stress. Disrupting tobacco SYP121 function by expressing a dominant-negative Sp2 fragment had severe effects on growth, development, and traffic to the plasma membrane, and it blocked K+ and Cl− channel responses to abscisic acid in guard cells. These observations raise questions about SNARE control in exocytosis and endocytosis of ion channel proteins and their organization within the plane of the membrane. We have used a dual, in vivo tagging strategy with a photoactivatable green fluorescent protein and externally exposed hemagglutinin epitopes to monitor the distribution and trafficking dynamics of the KAT1 K+ channel transiently expressed in tobacco leaves. KAT1 is localized to the plasma membrane within positionally stable microdomains of ∼0.5 μm in diameter; delivery of the K+ channel, but not of the PMA2 H+-ATPase, to the plasma membrane is suppressed by Sp2 fragments of tobacco and Arabidopsis SYP121, and Sp2 expression leads to profound changes in KAT1 distribution and mobility within the plane of the plasma membrane. These results offer direct evidence for SNARE-mediated traffic of the K+ channel and a role in its distribution within subdomains of the plasma membrane, and they implicate a role for SNAREs in positional anchoring of the K+ channel protein.
A Small Family ofMYB-Regulatory Genes Controls Floral Pigmentation Intensity and Patterning in the GenusAntirrhinum
Authors: Schwinn Kathy , Venail Julien , Shang Yongjin , Mackay Steve , Alm Vibeke , Butelli Eugenio , Oyama Ryan , Bailey Paul , Davies Kevin , Martin Cathie 
Published: March 2006

AbstractThe Rosea1, Rosea2, and Venosa genes encode MYB-related transcription factors active in the flowers of Antirrhinum majus. Analysis of mutant phenotypes shows that these genes control the intensity and pattern of magenta anthocyanin pigmentation in flowers. Despite the structural similarity of these regulatory proteins, they influence the expression of target genes encoding the enzymes of anthocyanin biosynthesis with different specificities. Consequently, they are not equivalent biochemically in their activities. Different species of the genus Antirrhinum, native to Spain and Portugal, show striking differences in their patterns and intensities of floral pigmentation. Differences in anthocyanin pigmentation between at least six species are attributable to variations in the activity of the Rosea and Venosa loci. Set in the context of our understanding of the regulation of anthocyanin production in other genera, the activity of MYB-related genes is probably a primary cause of natural variation in anthocyanin pigmentation in plants.
Highly Specific Gene Silencing by Artificial MicroRNAs inArabidopsis
Authors: Schwab Rebecca , Ossowski Stephan , Riester Markus , Warthmann Norman , Weigel Detlef 
Published: March 2006

AbstractPlant microRNAs (miRNAs) affect only a small number of targets with high sequence complementarity, while animal miRNAs usually have hundreds of targets with limited complementarity. We used artificial miRNAs (amiRNAs) to determine whether the narrow action spectrum of natural plant miRNAs reflects only intrinsic properties of the plant miRNA machinery or whether it is also due to past selection against natural miRNAs with broader specificity. amiRNAs were designed to target individual genes or groups of endogenous genes. Like natural miRNAs, they had varying numbers of target mismatches. Previously determined parameters of target selection for natural miRNAs could accurately predict direct targets of amiRNAs. The specificity of amiRNAs, as deduced from genome-wide expression profiling, was as high as that of natural plant miRNAs, supporting the notion that extensive base pairing with targets is required for plant miRNA function. amiRNAs make an effective tool for specific gene silencing in plants, especially when several related, but not identical, target genes need to be downregulated. We demonstrate that amiRNAs are also active when expressed under tissue-specific or inducible promoters, with limited nonautonomous effects. The design principles for amiRNAs have been generalized and integrated into a Web-based tool (http://wmd.weigelworld.org).
Salicylic Acid–Independent ENHANCED DISEASE SUSCEPTIBILITY1 Signaling inArabidopsisImmunity and Cell Death Is Regulated by the MonooxygenaseFMO1and the Nudix HydrolaseNUDT7
Authors: Bartsch Michael , Gobbato Enrico , Bednarek Pawel , Debey Svenja , Schultze Joachim L. , Bautor Jaqueline , Parker Jane E. 
Published: March 2006

AbstractArabidopsis thaliana ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) controls defense activation and programmed cell death conditioned by intracellular Toll-related immune receptors that recognize specific pathogen effectors. EDS1 is also needed for basal resistance to invasive pathogens by restricting the progression of disease. In both responses, EDS1, assisted by its interacting partner, PHYTOALEXIN-DEFICIENT4 (PAD4), regulates accumulation of the phenolic defense molecule salicylic acid (SA) and other as yet unidentified signal intermediates. An Arabidopsis whole genome microarray experiment was designed to identify genes whose expression depends on EDS1 and PAD4, irrespective of local SA accumulation, and potential candidates of an SA-independent branch of EDS1 defense were found. We define two new immune regulators through analysis of corresponding Arabidopsis loss-of-function insertion mutants. FLAVIN-DEPENDENT MONOOXYGENASE1 (FMO1) positively regulates the EDS1 pathway, and one member (NUDT7) of a family of cytosolic Nudix hydrolases exerts negative control of EDS1 signaling. Analysis of fmo1 and nudt7 mutants alone or in combination with sid2-1, a mutation that severely depletes pathogen-induced SA production, points to SA-independent functions of FMO1 and NUDT7 in EDS1-conditioned disease resistance and cell death. We find instead that SA antagonizes initiation of cell death and stunting of growth in nudt7 mutants.
TheTORNADO1andTORNADO2Genes Function in Several Patterning Processes during Early Leaf Development inArabidopsis thaliana
Authors: Cnops Gerda , Neyt Pia , Raes Jeroen , Petrarulo Marica , Nelissen Hilde , Malenica Nenad , Luschnig Christian , Tietz Olaf , Ditengou Franck , Palme Klaus , Azmi Abdelkrim , Prinsen Els , Van Lijsebettens Mieke 
Published: March 2006

AbstractIn multicellular organisms, patterning is a process that generates axes in the primary body plan, creates domains upon organ formation, and finally leads to differentiation into tissues and cell types. We identified the Arabidopsis thaliana TORNADO1 (TRN1) and TRN2 genes and their role in leaf patterning processes such as lamina venation, symmetry, and lateral growth. In trn mutants, the leaf venation network had a severely reduced complexity: incomplete loops, no tertiary or quaternary veins, and vascular islands. The leaf laminas were asymmetric and narrow because of a severely reduced cell number. We postulate that the imbalance between cell proliferation and cell differentiation and the altered auxin distribution in both trn mutants cause asymmetric leaf growth and aberrant venation patterning. TRN1 and TRN2 were epistatic to ASYMMETRIC LEAVES1 with respect to leaf asymmetry, consistent with their expression in the shoot apical meristem and leaf primordia. TRN1 codes for a large plant-specific protein with conserved domains also found in a variety of signaling proteins, whereas TRN2 encodes a transmembrane protein of the tetraspanin family whose phylogenetic tree is presented. Double mutant analysis showed that TRN1 and TRN2 act in the same pathway.
The U-Box Protein CMPG1 Is Required for Efficient Activation of Defense Mechanisms Triggered by Multiple Resistance Genes in Tobacco and Tomato
Authors: González-Lamothe Rocío , Tsitsigiannis Dimitrios I. , Ludwig Andrea A. , Panicot Mireia , Shirasu Ken , Jones Jonathan D.G. 
Published: March 2006

AbstractWe previously identified three Avr9/Cf-9 Rapidly Elicited (ACRE) genes essential for Cf-9– and Cf-4–dependent hypersensitive response (HR) production in Nicotiana benthamiana. Two of them encode putative E3 ubiquitin ligase components. This led us to investigate other ACRE genes associated with the ubiquitination pathway. ACRE74 encodes a U-box E3 ligase homolog, highly related to parsley (Petroselinum crispum) CMPG1 and Arabidopsis thaliana PLANT U-BOX20 (PUB20) and PUB21 proteins, and was called Nt CMPG1. Transcript levels of Nt CMPG1 and the homologous tomato (Solanum lycopersicum) Cmpg1 are induced in Cf9 tobacco (Nicotiana tabacum) and Cf9 tomato after Avr9 elicitation. Tobacco CMPG1 possesses in vitro E3 ligase activity. N. benthamiana plants silenced for Nt CMPG1 show reduced HR after Cf-9/Avr9 elicitation, while overexpression of Nt CMPG1 induces a stronger HR in Cf9 tobacco plants after Avr9 infiltration. In tomato, silencing of Cmpg1 decreased resistance to Cladosporium fulvum. Overexpression of epitope-tagged tobacco CMPG1 mutated in the U-box domain confers a dominant-negative phenotype. We also show that Nt CMPG1 is involved in the Pto/AvrPto and Inf1 responses. In summary, we show that the E3 ligase Nt CMPG1 is essential for plant defense and disease resistance.
Significant increase of colonic mutated crypts correlates with age in sporadic cancer and diverticulosis cases, with higher frequency in the left‐ than right‐side colorectum
Authors: Okayasu Isao , Hana Kiyomi , Tsuruta Tomoko , Okamura Nobuyoshi , Ogawa Taishi , Tokuyama Wataru , Kajita Sabine , Yoshida Tsutomu , Mikami Tetuo 
Published: March 2006

Mild periodic acid–Schiff (mPAS) staining can discriminate non‐O‐acetylated (mPAS‐positive) from O‐acetylated (mPAS‐negative) epithelial sialoglycoproteins in human colonic mucosa, allowing the three haplotypes expressed from a single polymorphic autosomal gene (oat) to be distinguished. In heterozygotes, we previously demonstrated wholly mPAS‐positive (stem cell mutated) crypts and clusters of two or more mPAS‐positive crypts to be significantly increased with duration of ulcerative colitis. To establish whether such an increase in the number of mutated crypts with age also occurs in normal individuals or in cases with diverticulosis, the O‐acetylation phenotype in the non‐cancerous colonic mucosa of 47 sporadic colorectal cancer patients who were heterozygotes for oat was tested with mild‐PAS staining. PAS‐positive crypts were assessed histologically in relation to age and compared between the left (sigmoid colon and rectum) and right (cecum and ascending colon) sides of the colorectum. Wholly mPAS‐positive (stem cell mutated) crypts and foci in heterozygotes were found to be increased significantly (P < 0.0001) in the left side with aging (r = 0.598 and 0.643, respectively). Such a positive correlation with aging was also confirmed in 19 diverticulosis cases without cancer (r = 0.797 and 0.793, respectively). The frequency of mutated crypts and foci on the right side was significantly lower than on the left side in both spontaneous colorectal cancer and diverticulosis cases. The results provide support for an intimate relationship between accumulation of mutated crypts with aging, possibly with significance for colorectal cancer development. Furthermore, the environment in the right side of the colon may be different from that in the left side in this regard. (Cancer Sci 2006; 97)
Plasminogen activator inhibitor‐1 as a potential marker for the malignancy of gastric cancer
Authors: Sakakibara Takumi , Hibi Kenji , Koike Masahiko , Fujiwara Michitaka , Kodera Yasuhiro , Ito Katsuki , Nakao Akimasa 
Published: March 2006

To test the hypothesis that plasminogen activator inhibitor‐1 (PAI‐1) may serve as a candidate marker for the malignancy of gastric cancer, we carried out quantitative reverse transcription–polymerase chain reaction for the PAI‐1 gene and evaluated the possible relationship between PAI‐1 gene expression levels and clinicopathological findings in gastric cancer. A significant increase in PAI‐1 expression scores was observed in lymph node metastasis‐positive gastric cancers (2.11 ± 0.35) compared to metastasis‐negative cancers (0.33 ± 0.49) (P = 0.0048), as well as in distant metastasis‐positive gastric cancers (3.68 ± 0.58) compared to metastasis‐negative cancers (1.20 ± 0.32). The PAI‐1 expression score markedly increased with tumor stage (P < 0.0001; ANOVA test). Moreover, multivariate analysis revealed the PAI‐1 expression score to be a strong and independent prognostic factor for gastric cancer (P = 0.0450). These results suggested that PAI‐1 might serve as a new and promising parameter for the prediction of prognosis in gastric cancer. (Cancer Sci 2006; 97)
A laboratory analysis of gutta‐percha‐filled area obtained using Thermafil, System B and lateral condensation
Authors: De‐Deus G. , Gurgel‐Filho E. D. , Magalhães K. M. , Coutinho‐Filho T. 
Published: March 2006

AbstractAim  To determine the percentage of gutta‐percha‐filled area (PGFA) in the apical third of root canals when filled with either Thermafil, System B or lateral condensation.Methodology  Sixty extracted human maxillary central incisor teeth were root filled as following: G1: lateral condensation (n = 20), G2: System B (n = 20) and G3: Thermafil system (n = 20). A horizontal section was cut 2 and 4 mm from the apical foramen of each tooth. The samples were prepared for microscopic analysis and photomicrographs of each apical surface were taken at a magnification of 50×. Through digital image analysis, the cross‐sectional area of the canal and the gutta‐percha was measured. The PGFA was calculated. The PGFA data obtained in the three groups were analysed using a nonparametric Friedman and Wilcoxon signed‐rank tests.Results  Significant differences in PGFA were found between the Thermafil System (G3) and both System B (G2) and lateral condensation (G1) (P < 0.01). The greatest PGFA occurred in the Thermafil group. No significant statistical difference was found between System B and lateral condensation (P > 0.05).Conclusions  The coated carrier gutta‐percha system Thermafil produced significantly higher PGFAs than lateral condensation and System B techniques.
A finite element analysis of ferrule design on restoration resistance and distribution of stress within a root
Authors: Ichim I. , Kuzmanovic D. V. , Love R. M. 
Published: March 2006

AbstractAim  To analyse the effect of ferrule height upon the mechanical resistance and stress distribution within a root to explain variations in the pattern of root fracture.Methodology  An extracted, intact, caries free, maxillary right central incisor was scanned by laser and then reconstructed on a computer to produce a model of the tooth and associated periodontal ligament. A simulated post/core/crown restoration was constructed on conventional tooth preparations with various ferrules. The crown was loaded with a simulated 500 N force and the simulated displacement of components and the tensile and compressive stress within the tooth structure were recorded.Results  Without a ferrule preparation, the simulated crown tilted to the labial and rotated distally. With increasing ferrule height the displacement and rotation of the crown reduced in conventional and crown‐lengthening models with maximum reduction occurring when the ferrule height reached 1.5 mm. In ferrule models, higher levels of tensile stress developed in internal (by a factor of 8) and mid‐root palatal (by a factor of 90) dentine at the cervical margin of the preparation. With an increase in ferrule height, the area of tensile stress within the palatal mid‐dentine expanded towards the cervical margin. Similar patterns and stress values were recorded for the crown‐lengthening models.Conclusion  The study confirms that a ferrule increases the mechanical resistance of a post/core/crown restoration. However a ferrule creates a larger area of palatal dentine under tensile stress that may be a favourable condition for a crack to develop. Crown‐lengthening did not alter the levels or pattern of stress within compared with conventional ferrule preparations.