bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Ser/Thr cluster within the C‐terminal domain of the rat prostaglandin receptor EP3α is essential for agonist‐induced phosphorylation, desensitization and internalization
Authors: Neuschäfer‐Rube Frank , Hermosilla Ricardo , Kuna Manuela , Pathe‐Neuschäfer‐Rube Andrea , Schülein Ralf , Püschel Gerhard Paul 
Published: June 2005

Two isoforms of the rat prostaglandin E2 receptor, rEP3α‐R and rEP3β‐R, differ only in their C‐terminal domain. To analyze the function of the rEP3‐R C‐terminal domain in agonist induced desensitization, a cluster of Ser/Thr residues in the C‐terminal domain of the rEP3α‐R was mutated to Ala and both isoforms and the receptor mutant (rEP3α‐ST341‐349A‐R) were stably expressed in HEK293 cells.
All rEP3‐R receptors showed a similar ligand‐binding profile. They were functionally coupled to Gi and reduced forskolin‐induced cAMP‐formation.
Repeated exposure of cells expressing the rEP3α‐R isoform to PGE2 reduced the agonist induced inhibition of forskolin‐stimulated cAMP‐formation by 50% and led to internalization of the receptor to intracellular endocytotic vesicles. By contrast, Gi‐response as well as plasma membrane localization of the rEP3β‐R and the rEP3α‐ST341‐349A‐R were not affected by prior agonist‐stimulation.
Agonist‐stimulation of HEK293‐rEP3α‐R cells induced a time‐ and dose‐dependent phosphorylation of the receptor most likely by G protein‐coupled receptor kinases and not by protein kinase A or protein kinase C. By contrast, upon agonist‐stimulation the rEP3β‐R was not phosphorylated and the rEP3α‐ST341‐349A‐R was phosphorylated only weakly.
These results led to the hypothesis that agonist‐induced desensitization of the rEP3α‐R isoform is mediated most likely by a GRK‐dependent phosphorylation of Ser/Thr residues 341–349. Phosphorylation then initiates uncoupling of the receptor from Gi protein and receptor internalization.

British Journal of Pharmacology (2005) 145, 1132–1142. doi:10.1038/sj.bjp.0706282
Molecular and pharmacological characteristics of transient voltage‐dependent K+ currents in cultured human pulmonary arterial smooth muscle cells
Authors: Iida Haruko , Jo Taisuke , Iwasawa Kuniaki , Morita Toshihiro , Hikiji Hisako , Takato Tsuyoshi , Toyo‐oka Teruhiko , Nagai Ryozo , Nakajima Toshiaki 
Published: June 2005

The A‐type voltage‐dependent K+ current (IA) has been identified in several types of smooth muscle cells including the pulmonary artery (PA), but little is known about the pharmacological and molecular characteristics of IA in human pulmonary arterial smooth muscle cells (hPASMCs). We investigated IA expressed in cultured PASMCs isolated from the human main pulmonary artery, using patch‐clamp techniques, reverse transcriptase–polymerase chain reaction (RT–PCR), quantitative real‐time RT–PCR and immunocytochemical studies.
With high EGTA and ATP in the pipette, the outward currents were dominated by a transient K+ current (IA), followed by a relatively small sustained outward current (IK).
IA was inhibited by 4‐aminopyridine (4‐AP) concentration‐dependently, and could be separated pharmacologically into two components by tetraethylammonium (TEA) sensitivity. A component was sensitive to TEA, and the second component was insensitive to TEA.
IA was inhibited by blood depressing substrate (BDS)‐II, a specific blocker of KV3.4 subunit, and phrixotoxin‐II, a specific blocker of KV4.2 and 4.3.
Flecainide inhibited IA concentration‐dependently, but it inhibited it preferentially in the presence of TEA (TEA‐insensitive IA).
Systematic screening of expression of KV genes using RT–PCR showed the definite presence of transcripts of the IA‐encoding genes for KV3.4, KV4.1, KV4.2 and KV4.3 as well as the IK‐encoding genes for KV1.1, KV1.5 and KV2.1. The real‐time RT–PCR analysis showed that the relative abundance of the encoding genes of IA α‐subunit and KV channel‐interacting proteins (KChIPs) was KV4.2>KV3.4>KV4.3 (long)>KV4.1, and KChIP3≫KChIP2, respectively.
The presence of KV3.4, KV4.2 and KV4.3 proteins was also demonstrated by immunocytochemical studies, and confirmed by immunohistochemical staining using intact human PA sections.
These results suggest that IA in cultured hPASMCs consists of two kinetically and pharmacologically distinct components, probably KV3.4 and KV4 channels.

British Journal of Pharmacology (2005) 146, 49–59. doi:10.1038/sj.bjp.0706285
Caveolin‐1 gene knockout impairs nitrergic function in mouse small intestine
Authors: El‐Yazbi Ahmed F , Cho Woo‐Jung , Boddy Geoffrey , Daniel Edwin E 
Published: June 2005

Caveolin‐1 is a plasma membrane‐associated protein that is responsible for caveolae formation. It plays an important role in the regulation of the function of different signaling molecules, among which are the different isoforms of nitric oxide synthase (NOS).
Nitric oxide (NO) is known to be an important inhibitory mediator in the mouse gut. Caveolin‐1 knockout mice (Cav1−/−) were used to examine the effect of caveolin‐1 absence on the NO function in the mouse small intestine (ileum and jejunum) compared to their genetic controls and BALB/c controls.
Immunohistochemical staining showed loss of caveolin‐1 and NOS in the jejunal smooth muscles and myenteric plexus interstitial cells of Cajal (ICC) of Cav1−/− mice; however, nNOS immunoreactive nerves were still present in myenteric ganglia.
Under nonadrenergic noncholinergic (NANC) conditions, small intestinal tissues from Cav1−/− mice relaxed to electrical field stimulation (EFS), as did tissues from control mice. Relaxation of tissues from control mice was markedly reduced by N‐omega‐nitro‐L‐arginine (10−4 M), but relaxation of Cav1−/− animals was affected much less. Also, Cav1−/− mice tissues showed reduced relaxation responses to sodium nitroprusside (100 μM) compared to controls; yet there were no significant differences in the relaxation responses to 8‐bromoguanosine‐3′ : 5′‐cyclic monophosphate (100 μM).
Apamin (10−6 M) significantly reduced relaxations to EFS in NANC conditions in Cav1−/− mice, but not in controls.
The data from this study suggest that caveolin‐1 gene knockout causes alterations in the smooth muscles and the ICC, leading to an impaired NO function in the mouse small intestine that could possibly be compensated by apamin‐sensitive inhibitory mediators.

British Journal of Pharmacology (2005) 145, 1017–1026. doi:10.1038/sj.bjp.0706289
A study of the protein requirements of the mature breeding ewe
Authors: Robinson J. J. , Forbes T. J. 
Published: June 2005

1. An experiment was carried out in which protein utilization in the pregnant ewe was studied using the nitrogen balance technique.2. Eight diets supplying four different intakes of crude protein and two different intakes of energy were each offered to eight individually penned ewes.3. The mean crude protein intakes per day were 7·2, 5·5, 4·1 and 3·0 g/kg W0·73 (where W = body-weight) and the metabolizable energy intakes 134 and 113 kcal/kg W0·73.4. N balances were carried out at 10–12, 14–16 and 18–20 weeks of gestation on five ewes from each treatment.5. The apparent digestibility of both dry matter and crude protein decreased with decreasing protein intake. With the high energy intake, the apparent dry-matter digestibility was increased and the apparent digestibility of crude protein decreased. Stage of gestation had no significant effect on the apparent digestibility of either of these constituents.6. N retention was not affected by the number of foetuses carried. With the higher energy intake and the higher protein intakes, the absolute retention of N was significantly increased at all stages of gestation. N retention increased with advancing pregnancy; the retentions at 10–12, 14–16 and 18–20 weeks of gestation being 0·086, 0·114 and 0·163 g/kg W0·73 per day respectively.7. The efficiency of utilization of apparently digested N was calculated from the regression of retained N as a percentage of apparently digested N against apparently digested N.8. The daily intakes of apparently digested N required for maximum efficiency were 0·551 and 0·620 g/kg W0·73 on the high and low energy intakes respectively. The daily intake for maximum efficiency decreased with advancing pregnancy, the values being 0·623, 0·587 and 0·567 g/kg W0·73 for the 10–12, 14–16 and 18–20 weeks of gestation respectively.9. The levels of N retained at maximum efficiency were 0·235 and 0·202 g/kg W0·73 per day for the high and low energy intakes respectively. The levels of N retained increased during pregnancy from 0·170 g/kg W0·73 per day at 10–12 weeks to 0·286 g/kg W0·73 at 18–20 weeks. The requirements for zero N balance were 0·072 and 0·153 g apparently digested N/kg W0·73 per day for the high and low energy intakes respectively. The requirement for zero N balance decreased from 0·176 g/kg W0·73 per day at 10–12 weeks to 0·071 g/kg W0·73 at 18–20 weeks.10. The results are discussed in relation to other research findings and current recommendations.
Physical growth and neurointegrative performance of survivors of protein–energy malnutrition
Authors: Pereira Sheila M. , Sundararaj Regina , Begum Almas 
Published: June 2005

1.The anthropometric measurements and neurointegrative performance of seventy-nine children aged 6–12 years who had survived kwashiorkor in early childhood were compared to those of 142 children who served as controls.2. For the boys the differences in height and weight between those who had survived protein-energy malnutrition (PEM) and the controls were significant (P< 0.01).3. For the girls the differences in height and weight between those who had survived PEM and the controls were not significant.4. In the tests chosen, the performances of the survivors of PEM was significantly poorer than that of the controls.5. There was no improvement in the performance when thirteen survivors were reassessed at 10 years of age.6. There was a significant difference in scholastic performance between the survivors of PEM and the normal controls. The scholastic performance of the siblings of PEM survivors was also significantly better than that of the PEM survivors.7. The dietary intakes at the time of reassessment were unsatisfactory in 25% of the survivors, but did not relate to their scholastic abilities.
Influence of caecal microflora and of two dietary protein levels on the adaptation of the exocrine pancreas: comparative study in germ-free and conventional rats
Authors: Lhoste Evelyne F. , Catala Isabelle , Fiszlewicz Michèle , Gueugneau A. M. , Popot Fran¸oise , Vaissade Pierre , Corring Tristan , Szylit Odette 
Published: June 2005

AbstractDietary proteins are degraded by both endogenous enzymes and the caecal microflora. In conventional rats the enzyme content of the pancreas depends on the amount of dietary protein. The influence of the caecal microflora on this process is unknown. We report here the effect of the caecal microflora on pancreatic enzymes (proteases, amylase (EC3.2.1.l), lipase (EC3.1.1.3)) and on colonic metabolites (NH3, urea, short-chain fatty acids). Germ-free and conventional male Fischer rats were fed for 3 weeks with a diet containing 220 or 450 g protein/kg provided as a mixture of fish concentrate and soyabean isolate. The excretion of NH3, and the pH were specifically increased by the high-protein diet in the germ-free rats. The higher production of isobutyrate, valerate and isovalerate in conventional rats fed on the high-protein diet reflected a high bacterial proteolytic activity since these short-chain fatty acids are specific indicators of this activity. The microflora hydrolysed urea to NH3and maintained the pH at neutrality whatever the amount of protein in the diet since there were changes in germ-free rats but not in conventional ones. In germ-free rats, amylase, trypsin (EC3.4.21.4), elastase (EC3.4.21.36) and carboxypeptidase A (EC3.4.17.1) specific activities were significantly lower than in conventional rats. The adaptation of the pancreas to the 450 g protein/kg diet was not impaired by the bacterial status except for the specific activity of chymotrypsin (EC3.4.21.1) which was more increased by this diet in germ-free than in conventional rats. Moreover, the specific activity of lipase increased only in conventional rats fed on the 450g protein/kg diet. In conclusion, we observed a relationship between the enzyme content of the pancreas and the presence or absence of the caecal microflora suggesting that bacterial fermentation influences pancreatic function.
Systemic Acquired Tolerance to Virulent Bacterial Pathogens in Tomato
Authors: Block Anna , Schmelz Eric , O'Donnell Phillip J. , Jones Jeffrey B. , Klee Harry J. 
Published: June 2005

Abstract
Recent studies on the interactions between plants and pathogenic microorganisms indicate that the processes of disease symptom development and pathogen growth can be uncoupled. Thus, in many instances, the symptoms associated with disease represent an active host response to the presence of a pathogen. These host responses are frequently mediated by phytohormones. For example, ethylene and salicylic acid (SA) mediate symptom development but do not influence bacterial growth in the interaction between tomato (Lycopersicon esculentum) and virulent Xanthomonas campestris pv vesicatoria (Xcv). It is not apparent why extensive tissue death is integral to a defense response if it does not have the effect of limiting pathogen proliferation. One possible function for this hormone-mediated response is to induce a systemic defense response. We therefore assessed the systemic responses of tomato to Xcv. SA- and ethylene-deficient transgenic lines were used to investigate the roles of these phytohormones in systemic signaling. Virulent and avirulent Xcv did induce a systemic response as evidenced by expression of defense-associated pathogenesis-related genes in an ethylene- and SA-dependent manner. This systemic response reduced cell death but not bacterial growth during subsequent challenge with virulent Xcv. This systemic acquired tolerance (SAT) consists of reduced tissue damage in response to secondary challenge with a virulent pathogen with no effect upon pathogen growth. SAT was associated with a rapid ethylene and pathogenesis-related gene induction upon challenge. SAT was also induced by infection with Pseudomonas syringae pv tomato. These data show that SAT resembles systemic acquired resistance without inhibition of pathogen growth.
CINNAMYL ALCOHOL DEHYDROGENASE-C and -D Are the Primary Genes Involved in Lignin Biosynthesis in the Floral Stem of Arabidopsis
Authors: Sibout Richard , Eudes Aymerick , Mouille Gregory , Pollet Brigitte , Lapierre Catherine , Jouanin Lise , Séguin Armand 
Published: June 2005

Abstract
During lignin biosynthesis in angiosperms, coniferyl and sinapyl aldehydes are believed to be converted into their corresponding alcohols by cinnamyl alcohol dehydrogenase (CAD) and by sinapyl alcohol dehydrogenase (SAD), respectively. This work clearly shows that CAD-C and CAD-D act as the primary genes involved in lignin biosynthesis in the floral stem of Arabidopsis thaliana by supplying both coniferyl and sinapyl alcohols. An Arabidopsis CAD double mutant (cad-c cad-d) resulted in a phenotype with a limp floral stem at maturity as well as modifications in the pattern of lignin staining. Lignin content of the mutant stem was reduced by 40%, with a 94% reduction, relative to the wild type, in conventional β-O-4–linked guaiacyl and syringyl units and incorportion of coniferyl and sinapyl aldehydes. Fourier transform infrared spectroscopy demonstrated that both xylem vessels and fibers were affected. GeneChip data and real-time PCR analysis revealed that transcription of CAD homologs and other genes mainly involved in cell wall integrity were also altered in the double mutant. In addition, molecular complementation of the double mutant by tissue-specific expression of CAD derived from various species suggests different abilities of these genes/proteins to produce syringyl-lignin moieties but does not indicate a requirement for any specific SAD gene.
The Structure of a Cyanobacterial Sucrose-Phosphatase Reveals the Sugar Tongs That Release Free Sucrose in the Cell
Authors: Fieulaine Sonia , Lunn John E. , Borel Franck , Ferrer Jean-Luc 
Published: June 2005

AbstractSucrose-phosphatase (SPP) catalyzes the final step in the pathway of sucrose biosynthesis in both plants and cyanobacteria, and the SPPs from these two groups of organisms are closely related. We have crystallized the enzyme from the cyanobacterium Synechocystis sp PCC 6803 and determined its crystal structure alone and in complex with various ligands. The protein consists of a core domain containing the catalytic site and a smaller cap domain that contains a glucose binding site. Two flexible hinge loops link the two domains, forming a structure that resembles a pair of sugar tongs. The glucose binding site plays a major role in determining the enzyme's remarkable substrate specificity and is also important for its inhibition by sucrose and glucose. It is proposed that the catalytic reaction is initiated by nucleophilic attack on the substrate by Asp9 and involves formation of a covalent phospho-Asp9-enzyme intermediate. From modeling based on the SPP structure, we predict that the noncatalytic SPP-like domain of the Synechocystis sucrose-phosphate synthase could bind sucrose-6F-phosphate and propose that this domain might be involved in metabolite channeling between the last two enzymes in the pathway of sucrose synthesis.
Transcriptional Profile of the Arabidopsis Root Quiescent Center
Authors: Nawy Tal , Lee Ji-Young , Colinas Juliette , Wang Jean Y. , Thongrod Sumena C. , Malamy Jocelyn E. , Birnbaum Kenneth , Benfey Philip N. 
Published: June 2005

AbstractThe self-renewal characteristics of stem cells render them vital engines of development. To better understand the molecular mechanisms that determine the properties of stem cells, transcript profiling was conducted on quiescent center (QC) cells from the Arabidopsis thaliana root meristem. The AGAMOUS-LIKE 42 (AGL42) gene, which encodes a MADS box transcription factor whose expression is enriched in the QC, was used to mark these cells. RNA was isolated from sorted cells, labeled, and hybridized to Affymetrix microarrays. Comparisons with digital in situ expression profiles of surrounding tissues identified a set of genes enriched in the QC. Promoter regions from a subset of transcription factors identified as enriched in the QC conferred expression in the QC. These studies demonstrated that it is possible to successfully isolate and profile a rare cell type in the plant. Mutations in all enriched transcription factor genes including AGL42 exhibited no detectable root phenotype, raising the possibility of a high degree of functional redundancy in the QC.
Lipid Transfer Proteins Enhance Cell Wall Extension in Tobacco
Authors: Nieuwland Jeroen , Feron Richard , Huisman Bastiaan A.H. , Fasolino Annalisa , Hilbers Cornelis W. , Derksen Jan , Mariani Celestina 
Published: June 2005

AbstractPlant cells are enclosed by a rigid cell wall that counteracts the internal osmotic pressure of the vacuole and limits the rate and direction of cell enlargement. When developmental or physiological cues induce cell extension, plant cells increase wall plasticity by a process called loosening. It was demonstrated previously that a class of proteins known as expansins are mediators of wall loosening. Here, we report a type of cell wall–loosening protein that does not share any homology with expansins but is a member of the lipid transfer proteins (LTPs). LTPs are known to bind a large range of lipid molecules to their hydrophobic cavity, and we show here that this cavity is essential for the cell wall–loosening activity of LTP. Furthermore, we show that LTP-enhanced wall extension can be described by a logarithmic time function. We hypothesize that LTP associates with hydrophobic wall compounds, causing nonhydrolytic disruption of the cell wall and subsequently facilitating wall extension.
Functional Hammerhead Ribozymes Naturally Encoded in the Genome of Arabidopsis thaliana
Authors: Przybilski Rita , Gräf Stefan , Lescoute Aurélie , Nellen Wolfgang , Westhof Eric , Steger Gerhard , Hammann Christian 
Published: June 2005

Abstract
The hammerhead ribozyme (HHRz) is an autocatalytic RNA motif found in subviral plant pathogens and transcripts of repetitive DNA sequences in animals. Here, we report the discovery and characterization of unique HHRzs encoded in a plant genome. Two novel sequences were identified on chromosome IV of Arabidopsis thaliana in a database search, which took into account recently defined structural requirements. The HHRzs are expressed in several tissues and coexist in vivo as both cleaved and noncleaved species. In vitro, both sequences cleave efficiently at physiological Mg2+ concentrations, indicative of functional loop–loop interactions. Kinetic analysis of loop nucleotide variants was used to determine a three-dimensional model of these tertiary interactions. Based on these results, on the lack of infectivity of hammerhead-carrying viroids in Arabidopsis, and on extensive sequence comparisons, we propose that the ribozyme sequences did not invade this plant by horizontal transfer but have evolved independently to perform a specific, yet unidentified, biological function.
Visualization of Diffuse Centromeres with Centromere-Specific Histone H3 in the Holocentric PlantLuzula nivea
Authors: Nagaki Kiyotaka , Kashihara Kazunari , Murata Minoru 
Published: June 2005

AbstractAlthough holocentric species are scattered throughout the plant and animal kingdoms, only holocentric chromosomes of the nematode worm Caenorhabditis elegans have been analyzed with centromeric protein markers. In an effort to determine the holocentric structure in plants, we investigated the snowy woodrush Luzula nivea. From the young roots, a cDNA encoding a putative centromere-specific histone H3 (LnCENH3) was successfully isolated based on sequence similarity among plant CENH3s. The deduced amino acid sequence was then used to raise an anti-LnCENH3 antibody. Immunostaining clearly revealed the diffuse centromere-like structure that appears in the linear shape at prophase to telophase. Furthermore, it was shown that the amount of LnCENH3 decreased significantly at interphase. The polar side positioning on each chromatid at metaphase to anaphase also confirmed that LnCENH3 represents one of the centromere-specific proteins in L. nivea. These data from L. nivea are compared with those from C. elegans, and common features of holocentric chromosomes are discussed.