bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression Profile and Cellular Localization of Maize Rpd3-Type Histone Deacetylases during Plant Development
Authors: Varotto Serena , Locatelli Sabrina , Canova Sabrina , Pipal Alexandra , Motto Mario , Rossi Vincenzo 
Published: October 2003

Abstract
We analyzed the expression profile and cellular localization of the maize (Zea mays) Rpd3-type histone deacetylases genes ZmRpd3/101, ZmRpd3/102, and ZmRpd3/108 (indicated as ZmHDA101, ZmHDA102, and ZmHDA108 in the Plant Chromatin Database). This study shows that maize Rpd3 transcripts are present in all the organs and cellular domains analyzed, but we found that their amounts change during development, accumulating in the inner region of the endosperm, in vascular zones of the nucellus, in the tapetum, and in the tetrads. A similar expression profile and nucleus-cytoplasmic localization was observed for ZmRpd3 proteins. Glutathione S-transferase pull-down assays show that ZmRpd3 proteins can interact with the maize retinoblastoma-related (ZmRBR1) protein, an important regulator of cell cycle progression, and with the maize retinoblastoma-associated protein (ZmRbAp1). However, the three ZmRpd3 proteins do not mutually compete in the binding. These results suggest a general role of ZmRpd3 genes in the plant cell cycle and development. These observations also provide indications on possible mechanisms regulating their transcription and protein accumulation. Similarities in the gene expression profiles and protein interactions may indicate that functional redundancy among members of the ZmRpd3 gene family exists. However, a degree of functional divergence is also supported by our findings.
Phosphorylation of the MAPKKK Regulator Ste50p in
Saccharomyces cerevisiae
: a Casein Kinase I Phosphorylation Site Is Required for Proper Mating Function
Authors: Wu Cunle , Arcand Mathieu , Jansen Gregor , Zhong Mei , Iouk Tatiana , Thomas David Y. , Meloche Sylvain , Whiteway Malcolm 
Published: October 2003

ABSTRACT

The Ste50 protein of
Saccharomyces cerevisiae
is a regulator of the Ste11p protein kinase. Ste11p is a member of the MAP3K (or MEKK) family, which is conserved from yeast to mammals. Ste50p is involved in all the signaling pathways that require Ste11p function, yet little is known about the regulation of Ste50p itself. Here, we show that Ste50p is phosphorylated on multiple serine/threonine residues in vivo. Threonine 42 (T42) is phosphorylated both in vivo and in vitro, and the protein kinase responsible has been identified as casein kinase I. Replacement of T42 with alanine (T42A) compromises Ste50p function. This mutation abolishes the ability of overexpressed Ste50p to suppress either the mating defect of a
ste20 ste50
deletion mutant or the mating defect of a strain with a Ste11p deleted from its sterile-alpha motif domain. Replacement of T42 with a phosphorylation-mimetic aspartic acid residue (T42D) permits wild-type function in all assays of Ste50p function. These results suggest that phosphorylation of T42 of Ste50p is required for proper signaling in the mating response. However, this phosphorylation does not seem to have a detectable role in modulating the high-osmolarity glycerol synthesis pathway.
d
-Xylose Metabolism in
Hypocrea jecorina
: Loss of the Xylitol Dehydrogenase Step Can Be Partially Compensated for by
lad1
-Encoded
l
-Arabinitol-4-Dehydrogenase
Authors: Seiboth Bernhard , Hartl Lukas , Pail Manuela , Kubicek Christian P. 
Published: October 2003

ABSTRACT

With the goal of the genetic characterization of the
d
-xylose pathway in
Hypocrea jecorina
(anamorph:
Trichoderma reesei
), we cloned the
xdh1
gene, encoding NA
D-
xylitol dehydrogenase, which catalyzes the second step of fungal
d
-xylose catabolism. This gene encodes a 363-amino-acid protein which has a mass of 38 kDa, belongs to the zinc-containing alcohol dehydrogenase family, exhibits high sequence identity to the published sequences of xylitol dehydrogenases from yeast origins, but contains a second, additional binding site for Zn
2+
. The enzyme catalyzed the NA
D-
dependent oxidation of xylitol and
d
-sorbitol and the NADH-dependent reduction of
d
-xylulose and
d
-fructose. No activity was observed with NADP,
l
-arabinose, or
l
-arabinitol. A single 1.4-kb transcript was formed during growth on xylan,
d
-xylose,
l
-arabinose,
l
-arabinitol and, at a lower abundance, xylitol,
d
-galactose, galactitol, and lactose but not on
d
-glucose and glycerol.
xdh1
deletion mutants exhibited 50% reduced growth rates on
d
-xylose, whereas growth rates on xylitol remained unaltered. These mutants contained 30% of the xylitol dehydrogenase activity of the parent strain, indicating the presence of a second xylitol dehydrogenase. This activity was shown to be due to
lad1
-encoded
l
-arabinitol-4-dehydrogenase, because
H. jecorina xdh1 lad1
double-deletion strains failed to grow on
d
-xylose or xylitol. In contrast,
lad1
deletion strains of
H. jecorina
grew normally on these carbon sources. These results show that
H. jecorina
contains a single xylitol dehydrogenase which is encoded by
xdh1
and is involved in the metabolism of
d
-xylose and that
lad1
-encoded
l
-arabinitol-4-dehydrogenase can compensate for it partially in mutants with a loss of
xdh1
function.
Transport of the Two Natural Auxins, Indole-3-Butyric Acid and Indole-3-Acetic Acid, in Arabidopsis
Authors: Rashotte Aaron M. , Poupart Julie , Waddell Candace S. , Muday Gloria K. 
Published: October 2003

Abstract
Polar transport of the natural auxin indole-3-acetic acid (IAA) is important in a number of plant developmental processes. However, few studies have investigated the polar transport of other endogenous auxins, such as indole-3-butyric acid (IBA), in Arabidopsis. This study details the similarities and differences between IBA and IAA transport in several tissues of Arabidopsis. In the inflorescence axis, no significant IBA movement was detected, whereas IAA is transported in a basipetal direction from the meristem tip. In young seedlings, both IBA and IAA were transported only in a basipetal direction in the hypocotyl. In roots, both auxins moved in two distinct polarities and in specific tissues. The kinetics of IBA and IAA transport appear similar, with transport rates of 8 to 10 mm per hour. In addition, IBA transport, like IAA transport, is saturable at high concentrations of auxin, suggesting that IBA transport is protein mediated. Interestingly, IAA efflux inhibitors and mutations in genes encoding putative IAA transport proteins reduce IAA transport but do not alter IBA movement, suggesting that different auxin transport protein complexes are likely to mediate IBA and IAA transport. Finally, the physiological effects of IBA and IAA on hypocotyl elongation under several light conditions were examined and analyzed in the context of the differences in IBA and IAA transport. Together, these results present a detailed picture of IBA transport and provide the basis for a better understanding of the transport of these two endogenous auxins.
ADP-Glucose Pyrophosphorylase Is Activated by Posttranslational Redox-Modification in Response to Light and to Sugars in Leaves of Arabidopsis and Other Plant Species
Authors: Hendriks Janneke H.M. , Kolbe Anna , Gibon Yves , Stitt Mark , Geigenberger Peter 
Published: October 2003

AbstractADP-glucose pyrophosphorylase (AGPase) catalyzes the first committed reaction in the pathway of starch synthesis. It was recently shown that potato (Solanum tuberosum) tuber AGPase is subject to redox-dependent posttranslational regulation, involving formation of an intermolecular Cys bridge between the two catalytic subunits (AGPB) of the heterotetrameric holoenzyme (A. Tiessen, J.H.M. Hendriks, M. Stitt, A. Branscheid, Y. Gibon, E.M. Farré, P. Geigenberger [2002] Plant Cell 14: 2191–2213). We show here that AGPase is also subject to posttranslational regulation in leaves of pea (Pisum sativum), potato, and Arabidopsis. Conversion is accompanied by an increase in activity, which involves changes in the kinetic properties. Light and sugars act as inputs to trigger posttranslational regulation of AGPase in leaves. AGPB is rapidly converted from a dimer to a monomer when isolated chloroplasts are illuminated and from a monomer to a dimer when preilluminated leaves are darkened. AGPB is converted from a dimer to monomer when sucrose is supplied to leaves via the petiole in the dark. Conversion to monomeric form increases during the day as leaf sugars increase. This is enhanced in the starchless phosphoglucomutase mutant, which has higher sugar levels than wild-type Columbia-0. The extent of AGPB monomerization correlates with leaf sugar levels, and at a given sugar content, is higher in the light than the dark. This novel posttranslational regulation mechanism will allow starch synthesis to be regulated in response to light and sugar levels in the leaf. It complements the well-characterized regulation network that coordinates fluxes of metabolites with the recycling of phosphate during photosynthetic carbon fixation and sucrose synthesis.
Molecular Cloning and Functional Analysis of a Novel Type of Bowman-Birk Inhibitor Gene Family in Rice
Authors: Qu Li-Jia , Chen Jun , Liu Meihua , Pan Naisui , Okamoto Haruko , Lin Zhongzhuan , Li Chengyun , Li Donghui , Wang Jinling , Zhu Guofeng , Zhao Xin , Chen Xi , Gu Hongya , Chen Zhangliang 
Published: October 2003

Abstract
Bowman-Birk inhibitor (BBI) genes encode serine protease inhibitors that have repetitive cysteine-rich domains with reactive sites for the trypsin or chymotrypsin family. We have identified seven BBI genes from japonica rice (Oryza sativa subsp. japonica var Teqing). All of the genes identified were found in a single cluster on the southern end of the long arm of rice chromosome 1. Four of the seven BBI genes have two repetitive cysteine-rich domains, whereas one has a truncated domain with only one reactive site. We have also identified three novel BBI genes, each of which possesses three repetitive domains instead of two. In situ hybridization analyses indicated that the accumulation of rice BBI transcripts was differentially regulated in germinating embryos and also in the leaves, roots, and flower organs at later developmental stages. Different members of the rice BBI gene family displayed different expression patterns during rice seed germination, and wounding induced the expression of rice BBI transcripts. The three-domain BBIs had higher expression levels than the two-domain BBIs. It was also found that the mRNA of rice BBI genes was present in abundant amounts in scutellar epithelium and aleurone layer cells. RBBI3-1, one of the three-domain RBBI, exhibited in vitro trypsin-inhibiting activity but no chymotrypsin-inhibiting activity. Overexpression of RBBI2-3 in transgenic rice plants resulted in resistance to the fungal pathogen Pyricularia oryzae, indicating that proteinase inhibitors confer resistance against the fungal pathogen in vivo and that they might play a role in the defense system of the rice plant.
DNA Sequence-Based „Bar Codes” for Tracking the Origins of Expressed Sequence Tags from a Maize cDNA Library Constructed Using Multiple mRNA Sources
Authors: Qiu Fang , Guo Ling , Wen Tsui-Jung , Liu Feng , Ashlock Daniel A. , Schnable Patrick S. 
Published: October 2003

Abstract
To enhance gene discovery, expressed sequence tag (EST) projects often make use of cDNA libraries produced using diverse mixtures of mRNAs. As such, expression data are lost because the origins of the resulting ESTs cannot be determined. Alternatively, multiple libraries can be prepared, each from a more restricted source of mRNAs. Although this approach allows the origins of ESTs to be determined, it requires the production of multiple libraries. A hybrid approach is reported here. A cDNA library was prepared using 21 different pools of maize (Zea mays) mRNAs. DNA sequence „bar codes” were added during first-strand cDNA synthesis to uniquely identify the mRNA source pool from which individual cDNAs were derived. Using a decoding algorithm that included error correction, it was possible to identify the source mRNA pool of more than 97% of the ESTs. The frequency at which a bar code is represented in an EST contig should be proportional to the abundance of the corresponding mRNA in the source pool. Consistent with this, all ESTs derived from several genes (zein and adh1) that are known to be exclusively expressed in kernels or preferentially expressed under anaerobic conditions, respectively, were exclusively tagged with bar codes associated with mRNA pools prepared from kernel and anaerobically treated seedlings, respectively. Hence, by allowing for the retention of expression data, the bar coding of cDNA libraries can enhance the value of EST projects.
Constitutive and Hyperresponsive Signaling by Mutant Forms of
Saccharomyces cerevisiae
Amino Acid Sensor Ssy1
Authors: Gaber Richard F. , Ottow Kim , Andersen Helge A. , Kielland-Brandt Morten C. 
Published: October 2003

ABSTRACT

Sensing of extracellular amino acids results in transcriptional induction of amino acid permease genes in yeast. Ssy1, a membrane protein resembling amino acid permeases, is required for signaling but is apparently unable to transport amino acids and is thus believed to be a sensor. By using a novel genetic screen in which potassium uptake was made dependent on amino acid signaling, we obtained gain-of-function mutations in
SSY1
. Some alleles confer inducer-independent signaling; others increase the apparent affinity for inducers. The results reveal that amino acid transport is not required for signaling and support the notion that sensing by Ssy1 occurs via its direct interaction with extracellular amino acids.
Synaptic structure and diffusion dynamics of synaptic receptors
Authors: Triller Antoine , Choquet Daniel 
Published: October 2003

AbstractNeurotransmitter receptors are concentrated at synaptic sites through interactions with specific scaffolding proteins and cytoskeletal elements, but can also be found in intracellular compartments or dispersed in the membrane. The notion has emerged in recent years that this distribution results from a dynamic equilibrium between the different pools of receptors. This equilibrium is regulated by neuronal activity and interactions with scaffolding proteins. A change in its set point can result in rapid variations in the number of functional receptors at synapses such as seen during plasticity. Trafficking of receptors in and out of synapses has up to now mainly been viewed within the framework of endo/exocytotic processes. After a brief presentation of the strucure of excitatory and inhibitory synapses, we review data indicating that the lateral diffusion of receptors in the plane of the membrane is also a key step to regulate receptor stabilization and accumulation at synapses.
New vanadate‐induced Ca2+pathway in human red cells
Authors: Romero Pedro J. , Romero Eneida A. 
Published: October 2003

AbstractVanadate is a commonly used Ca2+pump blocker, exerting a substantial effect on Ca2+extrusion at millimolar concentrations in human red cells. At such levels, vanadate also seems to open an L type‐like Ca2+channel in these cells (J Biol Chem 257 (1982) 7414; Gen Physiol Biophys 16 (1997) 359). Since neither a dose‐dependence effect nor a metabolic requirement for the latter action could be found in the literature, we have addressed this matter in the present work. Accordingly, vanadate action on Ca2+entry was systematically investigated in both young and old human red cells after metabolic depletion. Although vanadate enhanced Ca2+entry indifferently in either cell type, a distinct over‐all effect was paradoxically found depending on whether or not metabolic substrates that give rise to ATP were present. In ATP‐depleted cells, unlike with ATP‐containing cells, vanadate‐stimulated Ca2+entry was neither blocked by raising external K+nor by adding voltage‐dependent Ca2+channel blockers (nifedipine, calciseptine, FTX3.3) or compounds affecting polyphosphoinositide metabolism (Li+, neomycin). Likewise, full substitution of external Na+by other cations did not inhibit vanadate‐enhanced Ca2+entry. Regardless of the cell age, stimulation by vanadate depended strongly on internal Na+(0–30 mM). Vanadate stimulation was significantly reduced (about 55%) by heparin (10 mg/ml) only in young cells and by ryanodine (about 35%, 250 μM) in old cells. The results suggest presence of a new vanadate‐induced Ca2+entry pathway in ATP‐depleted cells.
In vivo study of biodegradable alginate antibiotic beads in rabbits
Authors: Ueng Steve W. N. , Yuan Li‐Jen , Lee Ning , Lin Song‐Shu , Chan Err‐Cheng , Weng Jui‐Hsun 
Published: October 2003

AbstractThe authors investigated the lyophilized poly‐L‐lysine‐coated alginate antibiotic delivery system in vivo for the treatment of musculoskeletal infections. The sodium alginate was mixed with vancomycin, coated with poly‐L‐lysine and lyophilized to form 3 mm in diameter biodegradable antibiotic beads. The antibiotic beads were implanted in the distal femoral cavities of rabbits for in vivo investigation. The local concentration of vancomycin was well above the minimal inhibitory concentration of Staphylococcus aureus for 21 days. The release was most marked during the first two days. The diameters of sample inhibition zone ranged from 8 to 16 mm, the relative activity of vancomycin ranged from 12.5% to 100%. The blood level of vancomycin reached its peak (46.0 mg/l) two days after implantation and fell to 3.2 mg/l at two weeks. It was undetectable after three weeks. There was no increase in the concentration of blood urea nitrogen and serum creatinine after the implantation. Histological observations showed that bead materials were biodegradable, resorbed slowly and only cause mild host reaction. This study offers a biodegradable delivery system of antibiotics to treat musculoskeletal infections. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Invasive assessment of bacterial endotoxin and inflammatory cytokines in patients with acute heart failure
Authors: Peschel Thomas , Schönauer Martin , Thiele Holger , Anker Stefan , Schuler Gerhard , Niebauer Josef 
Published: October 2003

AbstractAims:To test the hypothesis that during acute heart failure endotoxin might be increased in hepatic veins as a sign of bacterial or endotoxin translocation from the bowel into the blood stream.Methods and results:In patients with acute heart failure (NYHA IV; n=17) levels of endotoxin, soluble (s) CD14, tumor necrosis factor α (TNFα and interleukin 6 (IL6)) were measured in blood drawn from an antecubital vein on admission and compared with age‐matched patients with stable chronic heart failure (n=21) and healthy volunteers (n=9). All levels were systemically elevated during acute heart failure (all P<0.05); once patients were stable enough to undergo cardiac catheterization, endotoxin was found to be significantly higher in hepatic veins (0.62±0.05 EU/ml) than left ventricles (0.46±0.04 EU/ml; P<0.05), whereas sCD14, TNFα and IL6 were not different between these sites. At follow‐up (29±6 days) endotoxin but not sCD14, TNFα or IL‐6 was significantly lower as compared to baseline (P<0.05).Conclusions:Higher levels of endotoxin in hepatic veins as compared to the left ventricle during acute heart failure are suggestive of bacterial or endotoxin translocation from the bowel into the blood stream. This may lead to new treatment strategies. The lack of difference in TNFα levels between the pulmonary artery and the left ventricle sheds doubt on the heart as a source of systemically elevated TNFα levels.
Ethylene and Auxin Control the Arabidopsis Response to Decreased Light Intensity
Authors: Vandenbussche Filip , Vriezen Willem H. , Smalle Jan , Laarhoven Lucas J.J. , Harren Frans J.M. , Van Der Straeten Dominique 
Published: October 2003

AbstractMorphological responses of plants to shading have long been studied as a function of light quality, in particular the ratio of red to far red light that affects phytochrome activity. However, changes in light quantity are also expected to be important for the shading response because plants have to adapt to the reduction in overall energy input. Here, we present data on the involvement of auxin and ethylene in the response to low light intensities. Decreased light intensities coincided with increased ethylene production in Arabidopsis rosettes. This response was rapid because the plants reacted within minutes. In addition, ethylene- and auxin-insensitive mutants are impaired in their reaction to shading, which is reflected by a defect in leaf elevation and an aberrant leaf biomass allocation. On the molecular level, several auxin-inducible genes are up-regulated in wild-type Arabidopsis in response to a reduction in light intensity, including the primary auxin response gene IAA3 and a protein with similarity to AUX22 and the 1-aminocyclopropane-1-carboxylic acid synthase genes ACS6, ACS8, and ACS9 that are involved in ethylene biosynthesis. Taken together, the data show that ethylene and auxin signaling are required for the response to low light intensities.
Functional Characterization and Expression of a Cytosolic Iron-Superoxide Dismutase from Cowpea Root Nodules,
Authors: Moran Jose F. , James Euan K. , Rubio Maria C. , Sarath Gautam , Klucas Robert V. , Becana Manuel 
Published: October 2003

Abstract
An iron-superoxide dismutase (FeSOD) with an unusual subcellular localization, VuFeSOD, has been purified from cowpea (Vigna unguiculata) nodules and leaves. The enzyme has two identical subunits of 27 kD that are not covalently bound. Comparison of its N-terminal sequence (NVAGINLL) with the cDNA-derived amino acid sequence showed that VuFeSOD is synthesized as a precursor with seven additional amino acids. The mature protein was overexpressed in Escherichia coli, and the recombinant enzyme was used to generate a polyclonal monospecific antibody. Phylogenetic and immunological data demonstrate that there are at least two types of FeSODs in plants. An enzyme homologous to VuFeSOD is present in soybean (Glycine max) and common bean (Phaseolus vulgaris) nodules but not in alfalfa (Medicago sativa) and pea (Pisum sativum) nodules. The latter two species also contain FeSODs in the leaves and nodules, but the enzymes are presumably localized to the chloroplasts and plastids. In contrast, immunoblots of the soluble nodule fraction and immunoelectron microscopy of cryo-processed nodule sections demonstrate that VuFeSOD is localized to the cytosol. Immunoblot analysis showed that the content of VuFeSOD protein increases in senescent nodules with active leghemoglobin degradation, suggesting a direct or indirect (free radical-mediated) role of the released Fe in enzyme induction. Therefore, contrary to the widely held view, FeSODs in plants are not restricted to the chloroplasts and may become an important defensive mechanism against the oxidative stress associated with senescence.
Expression and Maintenance of Embryogenic Potential Is Enhanced through Constitutive Expression ofAGAMOUS-Like 15
Authors: Harding Ellen W. , Tang Weining , Nichols Karl W. , Fernandez Donna E. , Perry Sharyn E. 
Published: October 2003

AbstractThe MADS domain protein AGL15 (AGAMOUS-Like 15) has been found to preferentially accumulate in angiosperm tissues derived from double fertilization (i.e. the embryo, suspensor, and endosperm) and in apomictic, somatic, and microspore embryos. Localization to the nuclei supports a role in gene regulation during this phase of the life cycle. To test whether AGL15 is involved in the promotion and maintenance of embryo identity, the embryogenic potential of transgenic plants that constitutively express AGL15 was assessed. Expression of AGL15 was found to enhance production of secondary embryos from cultured zygotic embryos, and constitutive expression led to long-term maintenance of development in this mode. Ectopic accumulation of AGL15 also promoted somatic embryo formation after germination from the shoot apical meristem of seedlings in culture. These results indicate that AGL15 is involved in support of development in an embryonic mode.