bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphometric Investigations of Breed‐Specific Features in Feline Skulls and Considerations on their Functional Implications
Authors: Künzel W. , Breit S. , Oppel M. 
Published: July 2003

SummaryA total of 17 parameters (nine lengths, four heights, four widths) was used to characterize the shape of the skull in a sample of 69 pure bred cats. Results of the discriminant analysis confirmed three phenotypically different skull formations, i.e. the round‐shaped, the triangular and the cuneiform. Further statistical analyses revealed that the appearance of the skull was especially variable in the case of a round shape and that the lengths had been especially affected by these characteristics. The round shape of the brachycephalic skull was attributed to a reduction in length of the face and braincase as well. In many cases, this condition was associated with disproportional increase in height and width of the braincase and an increase in convexity of the calvaria. The decrease in length of the face was more pronounced at the dorsal surface of the nose than at the palate. Therefore, the inclination of the bony nasal aperture became flatter and the inclination of the maxilloturbinate became steeper. As a result, the ventral nasal meatus changed its direction twice. This condition might predispose to dyspnoea by restricting the air passageways within the nasal cavity. Round‐shaped skulls were also associated with a decrease in facial width. Morphological variants that were frequently seen in round‐shaped skulls include almost rectangular inclination of the nasal bone and more distant extension of the foramen magnum between the occipital condyles.
The peri‐albumen layer: a novel structure in the envelopes of an avian egg
Authors: Sultana F. , Yokoe A. , Ito Y. , Mao K. M. , Yoshizaki N. 
Published: July 2003

AbstractThe present paper describes a novel structure, termed the peri‐albumen layer, in the egg‐envelopes of the quail Coturnix japonica. It reacts with Alcian blue and exists between the egg white and the shell membrane. Ultrastructurally, it is of fine granular structure and forms a fenestrate sheet, the width of which is 190 nm or less. Isolated materials of the peri‐albumen layer include an Alcian‐blue‐positive polysaccharide of 260 kDa, and three glycoproteins of 160, 108 and 52 kDa. The layer is supplied to an egg when it passes through the magnum–isthmus junction, the normalized length of which is 0.62–0.63 of the oviduct. The mucosa of the junction consists exclusively of a luminal epithelium. It is apparently distinct from the mucosa of the magnum and the isthmus, which consist of a luminal epithelium and tubular glands. The luminal epithelium of the magnum–isthmus junction stains prominently with Alcian blue and consists of alternately distributed ciliated cells and granular cells. Immunohistochemistry with an antiserum raised against the materials of the peri‐albumen layer revealed the staining of the peri‐albumen layer of the egg, and secretory cells of the luminal epithelium at the magnum–isthmus junction. It was concluded that the materials of the peri‐albumen layer are produced by secretory cells at the magnum–isthmus junction of the oviduct.
Magnetic resonance images of the brain of a dwarf sperm whale (Kogia simus)
Authors: Marino L. , Sudheimer K. , Pabst D. A. , McLellan W. A. , Johnson J. I. 
Published: July 2003

AbstractCetacean (dolphin, whale and porpoise) brains are among the least studied mammalian brains because of the difficulty of collecting and histologically preparing such relatively rare and large specimens. Among cetaceans, there exist relatively few studies of the brain of the dwarf sperm whale (Kogia simus). Magnetic resonance imaging (MRI) offers a means of observing the internal structure of the brain when traditional histological procedures are not practical. Therefore, MRI has become a critical tool in the study of the brain of cetaceans and other large species. This paper represents the first MRI‐based anatomically labelled three‐dimensional description of the dwarf sperm whale brain. Coronal plane sections of the brain of a sub‐adult dwarf sperm whale were originally acquired and used to produce virtual digital scans in the other two orthogonal spatial planes. A sequential set of images in all three planes has been anatomically labelled and displays the proportions and positions of major neuroanatomical features.
Roles of HNK‐1 carbohydrate epitope and its synthetic glucuronyltransferase genes on migration of rat neural crest cells
Authors: Nagase Takashi , Sanai Yutaka , Nakamura Shun , Asato Hirotaka , Harii Kiyonori , Osumi Noriko 
Published: July 2003

AbstractHNK‐1 carbohydrate epitope is localized on the surface of avian neural crest cells (NCCs), and is necessary for their migration. However, it is still disputed whether the epitope works in similar ways in mammalian embryos. In this study, we found that HNK‐1 carbohydrate epitope was specifically detected in some of the cranial ganglia, migrating trunk NCCs and some non‐NCC derivatives in the rat embryo. Two genes encoding glucuronyltransferases that synthesize the HNK‐1 epitope in vitro (GlcAT‐P and GlcAT‐D) were recently identified in the rat. Interestingly, the NCCs in the cranial ganglia expressed the GlcAT‐D gene, whereas the migrating trunk NCCs expressed the GlcAT‐P gene. To investigate in vivo functions of the GlcATs in the NCC migration further, we overexpressed GlcAT genes by electroporation in the cranial NCCs in cultured rat embryos. Transfection of both GlcAT genes resulted in efficient synthesis of the HNK‐1 epitope in the NCCs. GlcAT‐P overexpression increased distance of cranial NCC migration, whereas GlcAT‐D overexpression did not show this effect. Our data suggest that the HNK‐1 epitope synthesized by different GlcATs is involved in migration in the sublineages of the NCCs in the rat embryo, and that GlcAT‐P and GlcAT‐D mediate different effects on the NCC migration.
Structural and functional relationships between type 1B heavy metal‐transporting P‐type ATPases in Arabidopsis
Authors: Cobbett Christopher S. , Hussain Dawar , Haydon Michael J. 
Published: July 2003

Summary Arabidopsis is remarkable for having eight members of the type 1B heavy metal‐transporting P‐type ATPase subfamily. Sequence analyses indicate that four, two of which may be targeted to plastids, are related to known Cu(I) transporters and contain N‐terminal metal‐binding site (MBS) motifs similar to those identified in other organisms. The remaining four are more closely related to known divalent cation transporters of prokaryotes. Three of these form a closely related group and are believed to be Zn(II) transporters. These contain a predicted N‐terminal MBS that is a variant of those found in Cu transporters in addition to extended C‐terminal regions that contain likely metal‐binding sequences. Our current limited knowledge of the physiological roles of these transporters is reviewed and their evolutionary relationships are explored, including an hypothesis that some, particularly the putative divalent cation transporters, are derived from horizontal gene transfer events.
Schizosaccharomyces pombeas a model for metal homeostasis in plant cells: the phytochelatin‐dependent pathway is the main cadmium detoxification mechanism
Authors: Clemens Stephan , Simm Claudia 
Published: July 2003

SummarySequestration of metal ions by phytochelatins is an important metal tolerance mechanism in a wide range of organisms including plants and certain fungi. Substantial progress in understanding phytochelatin formation at the molecular level has been made inSchizosaccharomyces pombe. The genome ofS. pombehas been completely sequenced and all the necessary tools of functional genomics are available. Since most other proteins implicated in plant metal tolerance and homeostasis are also present in this yeast, it represents a very powerful system to elucidate basic mechanisms of metal buffering, sequestration, and toxicity in cells that form phytochelatins. Here, we summarize the work on phytochelatin formation and metal homeostasis inS. pombe. We describe examples of molecular insights obtained from experiments withS. pombethat will be useful in guiding studies with plants. We also provide evidence for the dominance of the phytochelatin pathway in Cd detoxification inS. pombe.
Pharmacokinetic–pharmacodynamic study of apomorphine's effect on growth hormone secretion in healthy subjects
Authors: Aymard Guy , Berlin Ivan , De Brettes Benoît , Diquet Bertrand 
Published: July 2003

AbstractApomorphine (APO) stimulates growth hormone (GH) release via dopamine D2 receptors (DRD2). There is no specific study assessing the relationship between APO pharmacokinetic (PK) and the pharmacodynamic (PD) response e.g. GH release. The objective of the study is the PK–PD modelling of APO in healthy subjects. This is a randomized crossover study with s.c. administration of 5, 10, and 20 μg/kg of APO in 18 healthy subjects. APO concentrations were modelled according to both a bi‐compartmental model with zero‐order absorption and a bi‐compartmental model with first‐order absorption. PK–PD relationship was modelled in accordance with the Emax Hill equation using plasma concentrations of APO calculated according to the bi‐compartmental model with zero‐order absorption. Modelled parameters were very similar to the experimental parameters. PK of APO was linear and there was no significant difference between the tested doses for AUC0→∞ and Cmax (normalised to the dose 1 μg/kg), t1/2α and t1/2β. These parameters expressed as mean (CV%: SD/mean) were: 17.2 (26.9) ng/mL·min, 0.26 (33.3) ng/mL, 17.1 (54.2) and 45.2 (20.6) min, respectively (n = 53).An anticlockwise hysteresis loop (effect function of APO plasma concentration) appeared for each dose and each subject. The predicted and measured GH concentrations for all subjects and times were similar whatever the dose (P > 0.27). Emax values were 246 (121), 180 (107), 205 (139) ng/mL, respectively, and EC50 were 0.98 (48.1), 1.70 (62.3), 3.67 (65.2) ng/mL, respectively at dose 5, 10, and 20 μg/kg (P < 10−4). APO and GH concentrations were predicted with good accuracy using bi‐compartmental with zero‐order absorption PK model and sigmoid Emax PD model, respectively.
Alzheimer's disease: the pharmacological pathway
Authors: Allain Hervé , Bentué‐Ferrer Danièle , Tribut Olivier , Gauthier Serge , Michel Bernard‐François , Rochelle Christophe Drieu‐La 
Published: July 2003

AbstractThe current pharmacological treatment of Alzheimer's disease (AD) comes down to four marketed drugs (tacrine, donepezil, rivastigmine and galantamine) all of which are cholinesterase inhibitors, conforming to the cholinergic hypothesis. The future is clearly directed at new biological targets closely linked to the pathophysiology of the disease and more precisely, the pathological hallmark of AD which includes widespread neuronal degeneration, neuritic plaques containing β‐amyloid and τ‐rich neurofibrillary tangles. For clinicians, this means that new curative drugs will have to be prescribed early in the course of the disease. This review describes the main entry pathways for drug discovery in AD: (1) supplementation therapy, (2) anti‐apoptotic compounds, (3) substances with a mitochondrial impact, (4) anti‐amyloid substances, (5) anti‐protein aggregation and (6) lipid‐lowering drugs. The rapidity at which these compounds will be at our disposal is highly dependent on the policy of the pharmaceutical companies.
Adverse effects of conventional non‐steroidal anti‐inflammatory drugs on the upper gastrointestinal tract
Authors: Langman Michael J. S. 
Published: July 2003

AbstractThis article reviews the clinical and epidemiological features of conventional non‐steroidal anti‐inflammatory drug (NSAID) related peptic ulcer complications, and the associated risk factors. The degree of gastrointestinal toxicity varies widely between the available drugs and with dose of each. The risk of ulcer complications can however be reduced, and perhaps completely removed, by using the lowest dose of the least toxic member of the class. Enteric coating and other delayed release formulations have not been shown to reduce risk.Estimates of the imposed disease burden have varied widely, in part through assuming that risks in selected patient groups will necessarily translate to the general population. Nevertheless, the imposed disease burden is one of the largest associated with current drug treatment.Associated risk factors such as prior ulcer, corticosteroid use and concurrent aspirin as well as general cardiovascular disease will raise the likelihood of an ulcer complication in NSAID takers and non‐takers. Therefore, strategies dependent on substituting COX‐selective drugs will then be only partially successful.
Timing system for the start of gastrulation in the Xenopus embryo
Authors: Itoh Takeshi , Shinagawa Atsunori 
Published: July 2003

This study examined which component of the egg, the nucleus or cytoplasm, is involved in the timing of the start of gastrulation in the Xenopus embryo, and when it starts to measure time. First, nuclei of cells of 256‐cell stage embryos were transplanted to enucleated eggs 60 min after activation. These eggs showed first cleavage 20–30 min later than control eggs fertilized at the same time as the activation of recipient eggs, and started gastrulation 25–35 min later than control embryos (depending on the delay in the first cleavage). Second, eggs whose nuclei were temporarily isolated by the extrusion of the portion containing the nucleus out of the fertilization envelope showed first cleavage 60–90 min later than sibling control eggs, because of delayed introduction of the nucleus from the extruded portion. They started gastrulation 60–90 min later than sibling control embryos (depending on the delay in the first cleavage). The portion inside the envelope underwent two to three rounds of oscillation in cell cycle relevant activities before the first cleavage, while the portion outside underwent the same rounds of cleavage as the inside portion. From the present and previous results it is concluded that the putative timing system for the start of gastrulation in the Xenopus embryo, whether it consists of a single or of multiple clocks, starts measuring time at or around the first cleavage, and that the presence of both the nucleus and the cytoplasm in the same cell and occurrence of mitosis and/or cleavage there are indispensable for the timing system to work, although the role of the cytoplasm is superior to that of the nucleus.
Hydrotropism Interacts with Gravitropism by Degrading Amyloplasts in Seedling Roots of Arabidopsis and Radish
Authors: Takahashi Nobuyuki , Yamazaki Yutaka , Kobayashi Akie , Higashitani Atsushi , Takahashi Hideyuki 
Published: June 2003

Abstract
In response to a moisture gradient, roots exhibit hydrotropism to control the orientation of their growth. To exhibit hydrotropism, however, they must overcome the gravitropism that is dominant on Earth. We found that moisture gradient or water stress caused immediate degradation of the starch anchors, amyloplasts, in root columella cells of Arabidopsis and radish (Raphanus sativus). Namely, development of hydrotropic response was accompanied by a simultaneous reduction in starch content in columella cells. Rapid degradation of amyloplasts in columella cells also occurred in the water-stressed roots with sorbitol or mannitol. Both hydrotropically stimulated and water-stressed roots showed a reduced responsiveness to gravity. Roots of a starchless mutant, pgm1-1, showed an enhanced hydrotropism compared with that of the wild type. These results suggest that the reduced responsiveness to gravity is, at least in part, attributable to the degradation of amyloplasts in columella cells. Thus, the reduction in gravitropism allows the roots to exhibit hydrotropism.
An Arabidopsis Inositol 5-Phosphatase Gain-of-Function Alters Abscisic Acid Signaling
Authors: Burnette Ryan N. , Gunesekera Bhadra M. , Gillaspy Glenda E. 
Published: June 2003

AbstractSignals can be perceived and amplified at the cell membrane by receptors coupled to the production of a variety of second messengers, including inositol 1,4,5-trisphosphate (IP3). We previously have identified 15 putative inositol 5-phosphatases (5PTases) from Arabidopsis and shown that At5PTase1 can hydrolyze IP3. To determine whether At5PTase1 can terminate IP3-mediated signaling, we analyzed transgenic plants ectopically expressing At5PTase1. Stomata from leaves of At5PTase1 transgenic plants were abscisic acid (ABA) and light insensitive, and ABA induction of genes was delayed. Quantification of IP3 in plants exposed to ABA indicated that ABA induced two IP3 increases in wild-type plants. Both of these IP3 increases were reduced in At5PTase1 transgenic plants, indicating that IP3 may be necessary for stomatal closure and temporal control of ABA-induced gene expression. To determine if ABA could induce expression of At5PTase1, we examined RNA and protein levels of At5PTase1 in wild-type plants exposed to ABA. Our results indicate that At5PTase1 is up-regulated in response to ABA. This is consistent with At5PTase1 acting as a signal terminator of ABA signaling.
Inorganic Carbon Limitation and Light Control the Expression of Transcripts Related to the CO2-Concentrating Mechanism in the Cyanobacterium Synechocystis sp. Strain PCC6803
Authors: McGinn Patrick J. , Price G. Dean , Maleszka Ryszard , Badger Murray R. 
Published: June 2003

Abstract
The cyanobacterium Synechocystis sp. strain PCC6803 possesses three modes of inorganic carbon (Ci) uptake that are inducible under Ci stress and that dramatically enhance the efficiency of the CO2-concentrating mechanism (CCM). The effects of Ci limitation on the mRNA transcript abundance of these inducible uptake systems and on the physiological expression of the CCM were investigated in detail in this cyanobacterium. Transcript abundance was assessed with semiquantitative and real-time reverse transcriptase-polymerase chain reaction techniques. Cells aerated with CO2-free air for 30 min in the light, but not in the dark, depleted the total [Ci] to near zero levels. Under these conditions, the full physiological expression of the CCM was apparent within 2 h. Transcripts for the three inducible Ci uptake systems,ndhF3, sbtA, and cmpA, showed near-maximal abundance at 15 min under Ci limitation. The transcriptional regulators, cmpR andndhR, were more moderately expressed, whereas therbcLXS and ccmK-N operons andndhF4/ndhD4/chpX and ccaAgenes were insensitive to the low-Ci treatment. The combined requirement of low Ci and light for the expression of several CCM-related transcripts was examined using real-time reverse transcriptase-polymerase chain reaction. CmpA,ndhF3, and sbtA were strongly expressed in the light, but not in the dark, under low-Ci conditions. We could find no evidence for induction of these or other CCM-related genes by a high-light treatment under high-CO2 conditions. This provided evidence that high-light stress alone could not trigger the expression of CCM-related transcripts in Synechocystissp. PCC6803. Potential signals triggering induction of the high-affinity state of the CCM are discussed.
Nuclear Genes That Encode Mitochondrial Proteins for DNA and RNA Metabolism Are Clustered in the Arabidopsis Genome[W]
Authors: Elo Annakaisa , Lyznik Anna , Gonzalez Delkin O. , Kachman Stephen D. , Mackenzie Sally A. 
Published: July 2003

AbstractThe plant mitochondrial genome is complex in structure, owing to a high degree of recombination activity that subdivides the genome and increases genetic variation. The replication activity of various portions of the mitochondrial genome appears to be nonuniform, providing the plant with an ability to modulate its mitochondrial genotype during development. These and other interesting features of the plant mitochondrial genome suggest that adaptive changes have occurred in DNA maintenance and transmission that will provide insight into unique aspects of plant mitochondrial biology and mitochondrial-chloroplast coevolution. A search in the Arabidopsis genome for genes involved in the regulation of mitochondrial DNA metabolism revealed a region of chromosome III that is unusually rich in genes for mitochondrial DNA and RNA maintenance. An apparently similar genetic linkage was observed in the rice genome. Several of the genes identified within the chromosome III interval appear to target the plastid or to be targeted dually to the mitochondria and the plastid, suggesting that the process of endosymbiosis likely is accompanied by an intimate coevolution of these two organelles for their genome maintenance functions.
Molecular and Phylogenetic Analyses of the Complete MADS-Box Transcription Factor Family in Arabidopsis
Authors: Par̆enicová Lucie , de Folter Stefan , Kieffer Martin , Horner David S. , Favalli Cristina , Busscher Jacqueline , Cook Holly E. , Ingram Richard M. , Kater Martin M. , Davies Brendan , Angenent Gerco C. , Colombo Lucia 
Published: July 2003

AbstractMADS-box transcription factors are key regulators of several plant development processes. Analysis of the complete Arabidopsis genome sequence revealed 107 genes encoding MADS-box proteins, of which 84% are of unknown function. Here, we provide a complete overview of this family, describing the gene structure, gene expression, genome localization, protein motif organization, and phylogenetic relationship of each member. We have divided this transcription factor family into five groups (named MIKC, Mα, Mβ, Mγ, and Mδ) based on the phylogenetic relationships of the conserved MADS-box domain. This study provides a solid base for functional genomics studies into this important family of plant regulatory genes, including the poorly characterized group of M-type MADS-box proteins. MADS-box genes also constitute an excellent system with which to study the evolution of complex gene families in higher plants.
Gibberellin Biosynthesis and Response during Arabidopsis Seed Germination[W]
Authors: Ogawa Mikihiro , Hanada Atsushi , Yamauchi Yukika , Kuwahara Ayuko , Kamiya Yuji , Yamaguchi Shinjiro 
Published: July 2003

AbstractThe hormone-mediated control of plant growth and development involves both synthesis and response. Previous studies have shown that gibberellin (GA) plays an essential role in Arabidopsis seed germination. To learn how GA stimulates seed germination, we performed comprehensive analyses of GA biosynthesis and response using gas chromatography–mass spectrometry and oligonucleotide-based DNA microarray analysis. In addition, spatial correlations between GA biosynthesis and response were assessed by in situ hybridization. We identified a number of transcripts, the abundance of which is modulated upon exposure to exogenous GA. A subset of these GA-regulated genes was expressed in accordance with an increase in endogenous active GA levels, which occurs just before radicle emergence. The GA-responsive genes identified include those responsible for synthesis, transport, and signaling of other hormones, suggesting the presence of uncharacterized crosstalk between GA and other hormones. In situ hybridization analysis demonstrated that the expression of GA-responsive genes is not restricted to the predicted site of GA biosynthesis, suggesting that GA itself, or GA signals, is transmitted across different cell types during Arabidopsis seed germination.