bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of Cytosolic and Plastid Acetyl-Coenzyme A Carboxylase Genes in Young Wheat Plants,
Authors: Podkowinski Jan , Jelenska Joanna , Sirikhachornkit Anchalee , Zuther Ellen , Haselkorn Robert , Gornicki Piotr 
Published: February 2003

Abstract
Expression of cytosolic and plastid acetyl-coenzyme A carboxylase (ACCase) gene families at the mRNA level was analyzed in developing wheat (Triticum aestivum) plants. The major plastid ACCase mRNA level is high in the middle part of the plant and low in roots and leaf blades. An alternative plastid ACCase transcript initiated at a different promoter and using an alternative 5′ splice site for the first intron accumulates to its highest level in roots. Cytosolic ACCase mRNA also consists of two species, one of which is present at approximately a constant level, whereas the other accumulates to a high level in the lower sheath section. It is likely that different promoters are also responsible for the two forms of cytosolic ACCase mRNA. The abundances of cytosolic and plastid ACCase mRNAs in the sheath section of the plant are similar. ACCase protein level is significantly lower in the leaf blades, in parallel with changes in the total ACCase mRNA level. Homoeologous ACCase genes show the same expression patterns and similar mRNA levels, suggesting that none of the genes was silenced or acquired new tissue specificity after polyploidization.
Overexpression of Arabidopsis Phytochelatin Synthase Paradoxically Leads to Hypersensitivity to Cadmium Stress
Authors: Lee Sangman , Moon Jae S. , Ko Tae-Seok , Petros David , Goldsbrough Peter B. , Korban Schuyler S. 
Published: February 2003

Abstract
Phytochelatin (PC) plays an important role in heavy metal detoxification in plants and other living organisms. Therefore, we overexpressed an Arabidopsis PC synthase (AtPCS1) in transgenic Arabidopsis with the goal of increasing PC synthesis, metal accumulation, and metal tolerance in these plants. Transgenic Arabidopsis plants were selected, designated pcs lines, and analyzed for tolerance to cadmium (Cd). Transgenic pcs lines showed 12- to 25-fold higher accumulation ofAtPCS1 mRNA, and production of PCs increased by 1.3- to 2.1-fold under 85 μm CdCl2 stress for 3 d when compared with wild-type plants. Cd tolerance was assessed by measuring root length of plants grown on agar medium containing 50 or 85 μm CdCl2. Pcs lines paradoxically showed hypersensitivity to Cd stress. This hypersensitivity was also observed for zinc (Zn) but not for copper (Cu). The overexpressed AtPCS1 protein itself was not responsible for Cd hypersensitivity as transgeniccad1-3 mutants overexpressing AtPCS1 to similar levels as those of pcs lines were not hypersensitive to Cd. Pcs lines were more sensitive to Cd than a PC-deficient Arabidopsis mutant,cad1-3, grown under low glutathione (GSH) levels. Cd hypersensitivity of pcs lines disappeared under increased GSH levels supplemented in the medium. Therefore, Cd hypersensitivity in pcs lines seems due to the toxicity of PCs as they existed at supraoptimal levels when compared with GSH levels.
Rapid Alkalinization Factors in Poplar Cell Cultures. Peptide Isolation, cDNA Cloning, and Differential Expression in Leaves and Methyl Jasmonate-Treated Cells
Authors: Haruta Miyoshi , Constabel C. Peter 
Published: February 2003

Abstract
A family of peptides inducing rapid pH alkalinization in hybrid poplar (Populus trichocarpa × Populus deltoides) cell culture medium was isolated from hybrid poplar leaves. Five related approximately 5-kD peptides were purified by high-performance liquid chromatography and analyzed by matrix-assisted laser desorption ionization-mass spectrometry. The N-terminal sequence of one of the isolated peptides was very similar to a previously characterized peptide from tobacco (Nicotiana tabacum), rapid alkalinization factor (RALF), which causes a rapid increase in culture medium pH when added to tobacco cell cultures (G. Pearce, D.S. Moura, J. Stratmann, C.A. Ryan [2001] Proc Natl Acad Sci USA 98: 12843–12847). Two unique poplar RALF cDNAs (PtdRALF1 and PtdRALF2) were isolated from a poplar cDNA library and used to study RALF expression in poplar saplings and cultured poplar cells. Both genes were found to be expressed constitutively in poplar saplings and cultured cells. However, PtdRALF2 was expressed in leaves at very low levels, and its expression in suspension culture cells was transiently suppressed by methyl jasmonate (MeJa). Although the function of these novel peptides remains enigmatic, our experiments suggest their role may be developmental rather than stress related. Overall, our study confirms the presence of active RALF peptides in other plants, and provides new data on the complexity of the RALF gene family in poplar.
A STEP BEYOND KNESER'S THEOREM FOR ABELIAN FINITE GROUPS
Authors: DESHOUILLERS JEAN-MARC , FREIMAN GREGORY A. 
Published: February 2003

A precise description of a subset $\mathcal{A}$ of $\mathbb{Z} / n \mathbb{Z}$ satisfying$$ | \mathcal{A} + \mathcal{A} | \leq 2.04 | \mathcal{A} | $$is given. Basically, there exists a subgroup $\mathcal{H}$ of $\mathbb{Z} / n \mathbb{Z}$ such that $\mathcal{A}$ is included in an arithmetic progression of $\ell$ cosets modulo $\mathcal{H}$ and$$(\ell - 1) | \mathcal{H} | \leq | \mathcal{A} + \mathcal{A} | - | \mathcal{A} |.$$ 2000 Mathematical Subject Classification: 11B50, 11B83, 20E34.
RECTIFIABILITY OF MEASURES WITH LOCALLY UNIFORM CUBE DENSITY
Authors: LORENT ANDREW 
Published: February 2003

The conjecture that Radon measures in Euclidean space with positive finite density are rectifiable was a central problem in Geometric Measure Theory for fifty years. This conjecture was positively resolved by Preiss in 1986, using methods entirely dependent on the symmetry of the Euclidean unit ball. Since then, due to reasons of isometric immersion of metric spaces into $l_{\infty}$ and the uncommon nature of the sup norm even in finite dimensions, a popular model problem for generalising this result to non-Euclidean spaces has been the study of 2-uniform measures in $l^{3}_{\infty}$. The rectifiability or otherwise of these measures has been a well-known question.In this paper the stronger result that locally 2-uniform measures in $l^{3}_{\infty}$ are rectifiable is proved. This is the first result that proves rectifiability, from an initial condition about densities, for general Radon measures of dimension greater than 1 outside Euclidean space.2000 Mathematical Subject Classification: 28A75.
EQUIVARIANT PRINCIPAL BUNDLES OVER SPHERES AND COHOMOGENEITY ONE MANIFOLDS
Authors: HAMBLETON IAN , HAUSMANN JEAN-CLAUDE 
Published: February 2003

We classify smooth ${\rm SO}(n)$-equivariant principal bundles over $S^n$ in terms of their isotropy representations over the north and south poles. This is an example of a general result classifying equivariant $(\Pi, G)$-bundles over manifolds with cohomogeneity 1.2000 Mathematical Subject Classification: 55R91.
CRYSTAL BASES FOR QUANTUM AFFINE ALGEBRAS AND COMBINATORICS OF YOUNG WALLS
Authors: KANG SEOK-JIN 
Published: February 2003

In this paper we give a realization of crystal bases for quantum affine algebras using some new combinatorial objects which we call the Young walls. The Young walls consist of colored blocks with various shapes that are built on a given ground-state wall and can be viewed as generalizations of Young diagrams. The rules for building Young walls and the action of Kashiwara operators are given explicitly in terms of combinatorics of Young walls. The crystal graph of a basic representation is characterized as the set of all reduced proper Young walls. The character of a basic representation can be computed easily by counting the number of colored blocks that have been added to the ground-state wall.2000 Mathematical Subject Classification: 17B37, 17B65, 81R50, 82B23.
DILATATION AND ORDER OF CONTACT FOR HOLOMORPHIC SELF-MAPS OF STRONGLY CONVEX DOMAINS
Authors: BRACCI FILIPPO 
Published: February 2003

Let $D$ be a bounded strongly convex domain and let $f$ be a holomorphic self-map of $D$. In this paper we introduce and study the dilatation $\alpha (f)$ of $f$ defined, if $f$ has no fixed points in $D$, as the usual boundary dilatation coefficient of $f$ at its Wolff point, or, if $f$ has some fixed points in $D$, as the ratio of shrinking of the Kobayashi balls around a fixed point of $f$. In particular, we show that the map $\alpha$, defined as $\alpha : f \mapsto \alpha (f) \in [0,1]$, is lower semicontinuous. Among other things, this allows us to study the limits of a family of holomorphic self-maps of $D$. In the case of an inner fixed point, the dilatation is an intrinsic measure of the order of contact of $f(D)$ to $\partial D$.Finally, using complex geodesics, we define and study a directional dilatation, which is a measure of the shrinking of the domain along a given direction. Again, results of semicontinuity are given and applied to a family of holomorphic self-maps.2000 Mathematical Subject Classification: primary 32H99; secondary 30F99, 32H15.
BROUÉ'S CONJECTURE FOR THE HALL–JANKO GROUP AND ITS DOUBLE COVER
Authors: HOLLOWAY MILES 
Published: February 2003

Broué's abelian defect conjecture suggests a deep link between the module categories of a block of a group algebra and its Brauer correspondent, viz. that they should be derived equivalent. We are able to verify Broué's conjecture for the Hall–Janko group, even its double cover $2.J_2$, as well as for $U_3(4)$ and ${\rm Sp}_4(4)$. In fact we verify Rickard's refinement to Broué's conjecture and show that the derived equivalence can be chosen to be a splendid equivalence for these examples.2000 Mathematical Subject Classification: 20C20, 20C34.
DUNKL OPERATORS FOR COMPLEX REFLECTION GROUPS
Authors: DUNKL C. F. , OPDAM E. M. 
Published: February 2003

Dunkl operators for complex reflection groups are defined in this paper. These commuting operators give rise to a parameterized family of deformations of the polynomial De Rham complex. This leads to the study of the polynomial ring as a module over the ‘rational Cherednik algebra’, and a natural contravariant form on this module. In the case of the imprimitive complex reflection groups $G(m, p, N)$, the set of singular parameters in the parameterized family of these structures is described explicitly, using the theory of non-symmetric Jack polynomials.2000 Mathematical Subject Classification: 20F55 (primary), 52C35, 05E05, 33C08 (secondary).
Identification and Localization of Flagellins FlaA and FlaB3 within Flagella ofMethanococcus voltae
Authors: Bardy Sonia L. , Mori Takahisa , Komoriya Kaoru , Aizawa Shin-Ichi , Jarrell Ken F. 
Published: February 2003

ABSTRACTMethanococcus voltaepossesses four flagellin genes, two of which (flaB1andflaB2) have previously been reported to encode major components of the flagellar filament. The remaining two flagellin genes,flaAandflaB3, are transcribed at lower levels, and the corresponding proteins remained undetected prior to this work. Electron microscopy examination of flagella isolated by detergent extraction of whole cells revealed a curved, hook-like region of varying length at the end of a long filament. Enrichment of the curved region of the flagella resulted in the identification of FlaB3 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and N-terminal sequencing, and the localization of this flagellin to the cell-proximal portion of the flagellum was confirmed through immunoblotting and immunoelectron microscopy with FlaB3-specific antibodies, indicating that FlaB3 likely composes the curved portion of the flagella. This could represent a unique case of a flagellin performing the role of the bacterial hook protein. FlaA-specific antibodies were used in immunoblotting to determine that FlaA is found throughout the flagellar filament. M. voltaecells were transformed with a modifiedflaAgene containing a hemagglutinin (HA) tag introduced into the variable region. Transformants that had replaced the wild-type copy of theflaAgene with the HA-tagged version incorporated the HA-tagged version of FlaA into flagella which appeared normal by electron microscopy.
Identification of GtgE, a Novel Virulence Factor Encoded on the Gifsy-2 Bacteriophage ofSalmonella entericaSerovar Typhimurium
Authors: Ho Theresa D. , Figueroa-Bossi Nara , Wang Minhua , Uzzau Sergio , Bossi Lionello , Slauch James M. 
Published: February 2003

ABSTRACTThe Gifsy-2 temperate bacteriophage ofSalmonella entericaserovar Typhimurium contributes significantly to the pathogenicity of strains that carry it as a prophage. Previous studies have shown that Gifsy-2 encodes SodCI, a periplasmic Cu/Zn superoxide dismutase, and at least one additional virulence factor. Gifsy-2 encodes aSalmonellapathogenicity island 2 type III secreted effector protein. Sequence analysis of the Gifsy-2 genome also identifies several open reading frames with homology to those of known virulence genes. However, we found that null mutations in these genes did not individually have a significant effect on the ability ofS. entericaserovar Typhimurium to establish a systemic infection in mice. Using deletion analysis, we have identified a gene,gtgE, which is necessary for the full virulence ofS. entericaserovar Typhimurium Gifsy-2 lysogens. Together, GtgE and SodCI account for the contribution of Gifsy-2 toS. entericaserovar Typhimurium virulence in the murine model.
fleQ
, the Gene Encoding the Major Flagellar Regulator of
Pseudomonas aeruginosa
, Is σ
70
Dependent and Is Downregulated by Vfr, a Homolog of
Escherichia coli
Cyclic AMP Receptor Protein
Authors: Dasgupta Nandini , Ferrell Evan P. , Kanack Kristen J. , West Susan E. H. , Ramphal Reuben 
Published: February 2003

ABSTRACT

The flagellar transcriptional regulator FleQ appears to be the highest-level regulator in the hierarchical regulatory cascade of flagellar biogenesis in
Pseudomonas aeruginosa
. Except for the posttranslational downregulation of FleQ activity by FleN, an antiactivator, not much is known about the regulation of the
fleQ
gene or its gene product. Some FleQ homologs in other bacterial species either are positively regulated by another regulator (e.g., CtrA, the master regulator regulating FlbD in
Caulobacter crescentus
) or are expressed from a σ
70
-dependent promoter (e.g., FlgR of
Helicobacter pylori
). In this study we demonstrated that Vfr, an
Escherichia coli
CRP homolog known to function as an activator for various genes, including
lasR
,
regA
, and
toxA
, in
P. aeruginosa
, is capable of repressing
fleQ
transcription by binding to its consensus sequence in the
fleQ
promoter. In a DNase I footprint assay, purified Vfr protected the sequence 5′-AATTGACTAATCGTTCACATTTG-3′. When this putative Vfr binding site in the
fleQ
promoter was mutated, Vfr was unable to bind the
fleQ
promoter fragment and did not repress
fleQ
transcription effectively. Primer extension analysis of the
fleQ
transcript revealed two transcriptional start sites, t1 and t2, that map within the Vfr binding site. A putative −10 region (TAAAAT) for the t2 transcript, with a five-of-six match with the
E. coli
σ
70
binding consensus, overlaps with one end of the Vfr binding site. A 4-bp mutation and an 8-bp mutation in this −10 region markedly reduced the activity of the
fleQ
promoter. The same mutations led to the disappearance of the 203-nucleotide
fleQ
transcript in an in vitro transcription assay. Vfr probably represses
fleQ
transcription by binding to the Vfr binding site in the
fleQ
promoter and preventing the sigma factor from binding to the −10 region to initiate transcription.
FleQ, the Major Flagellar Gene Regulator in
Pseudomonas aeruginosa
, Binds to Enhancer Sites Located Either Upstream or Atypically Downstream of the RpoN Binding Site
Authors: Jyot Jeevan , Dasgupta Nandini , Ramphal Reuben 
Published: February 2003

ABSTRACT

In
Pseudomonas aeruginosa
, flagellar genes are regulated in a cascade headed by FleQ, an NtrC/NifA-type activator. FleQ and RpoN positively regulate expression of
flhA
,
fliE
,
fliL
, and
fleSR
genes, among others. Direct interaction of FleQ with
flhA
,
fliE
,
fliL
, and
fleSR
promoters was demonstrated by gel shift assay, along with experiments to conclusively determine the specificity of its binding. DNase I footprinting was performed to determine the FleQ binding sites on
flhA
,
fliE
,
fliL
, and
fleSR
promoters. No sequence conservation among these binding sites was observed. Primer extension analysis revealed the transcription start sites (TSSs) to be localized above the FleQ binding sites in
flhA
,
fliE
, and
fliL
promoters. Analysis of the above data revealed FleQ binding to be in the leader sequence of these promoters, whereas FleQ binding was 67 bp upstream of the TSS in the
fleSR
promoter. Mutagenesis of the FleQ binding site in the
flhA
promoter confirmed its functionality in vivo. Deletion of the
flhA
promoter upstream of the RNA polymerase binding site did not result in a significant loss of promoter activity. These results point to two modes of regulation by an NtrC-type regulator in the flagellar hierarchy in
P. aeruginosa
, the first being the typical model of activation from a distance via looping in the
fleSR
promoter and the second involving
flhA
,
fliE
, and
fliL
promoters, where FleQ binds in the downstream vicinity of the promoter and activates transcription without looping.
Metabolism of Dichloromethylcatechols as Central Intermediates in the Degradation of Dichlorotoluenes byRalstoniasp. Strain PS12
Authors: Pollmann Katrin , Kaschabek Stefan , Wray Victor , Reineke Walter , Pieper Dietmar H. 
Published: February 2003

ABSTRACTRalstoniasp. strain PS12 is able to use 2,4-, 2,5-, and 3,4-dichlorotoluene as growth substrates. Dichloromethylcatechols are central intermediates that are formed by TecA tetrachlorobenzene dioxygenase-mediated activation at two adjacent unsubstituted carbon atoms followed by TecB chlorobenzene dihydrodiol dehydrogenase-catalyzed rearomatization and then are channeled into a chlorocatecholorthocleavage pathway involving a chlorocatechol 1,2-dioxygenase, chloromuconate cycloisomerase, and dienelactone hydrolase. However, completely different metabolic routes were observed for the three dichloromethylcatechols analyzed. Whereas 3,4-dichloro-6-methylcatechol is quantitatively transformed into one dienelactone (5-chloro-2-methyldienelactone) and thus is degraded via a linear pathway, 3,5-dichloro-2-methylmuconate formed from 4,6-dichloro-3-methylcatechol is subject to both 1,4- and 3,6-cycloisomerization and thus is degraded via a branched metabolic route. 3,6-Dichloro-4-methylcatechol, on the first view, is transformed predominantly into one (2-chloro-3-methyl-trans-) dienelactone. In situ1H nuclear magnetic resonance analysis revealed the intermediate formation of 2,5-dichloro-4-methylmuconolactone, showing that both 1,4- and 3,6-cycloisomerization occur with this muconate and indicating a degradation of the muconolactone via a reversible cycloisomerization reaction and the dienelactone-forming branch of the pathway. Diastereomeric mixtures of two dichloromethylmuconolactones were prepared chemically to proof such a hypothesis. Chloromuconate cycloisomerase transformed 3,5-dichloro-2-methylmuconolactone into a mixture of 2-chloro-5-methyl-cis- and 3-chloro-2-methyldienelactone, affording evidence for a metabolic route of 3,5-dichloro-2-methylmuconolactone via 3,5-dichloro-2-methylmuconate into 2-chloro-5-methyl-cis-dienelactone. 2,5-Dichloro-3-methylmuconolactone was transformed nearly exclusively into 2-chloro-3-methyl-trans-dienelactone.
Cold Shock Response in SporulatingBacillus subtilisand Its Effect on Spore Heat Resistance
Authors: Movahedi Sara , Waites William 
Published: February 2003

ABSTRACTCold shock and ethanol and puromycin stress responses in sporulatingBacillus subtiliscells have been investigated. We show that a total of 13 proteins are strongly induced after a short cold shock treatment of sporulating cells. The cold shock pretreatment affected the heat resistance of the spores formed subsequently, with spores heat killed at 85 or 90°C being more heat resistant than the control spores while they were more heat sensitive than controls that were heat treated at 95 or 100°C. However,B. subtilisspores with mutations in the main cold shock proteins, CspB, -C, and -D, did not display decreased heat resistance compared to controls, indicating that these proteins are not directly responsible for the increased heat resistance of the spores. The disappearance of the stress proteins later in sporulation suggests that they cannot be involved in repairing heat damage during spore germination and outgrowth but must alter spore structure in a way which increases or decreases heat resistance. Since heat, ethanol, and puromycin stress produce similar proteins and similar changes in spore heat resistance while cold shock is different in both respects, these alterations appear to be very specific.
A New Modified
ortho
Cleavage Pathway of 3-Chlorocatechol Degradation by
Rhodococcus opacus
1CP: Genetic and Biochemical Evidence
Authors: Moiseeva Olga V. , Solyanikova Inna P. , Kaschabek Stefan R. , Gröning Janosch , Thiel Monika , Golovleva Ludmila A. , Schlömann Michael 
Published: February 2003

ABSTRACT

The 4-chloro- and 2,4-dichlorophenol-degrading strain
Rhodococcus opacus
1CP has previously been shown to acquire, during prolonged adaptation, the ability to mineralize 2-chlorophenol. In addition, homogeneous chlorocatechol 1,2-dioxygenase from 2-chlorophenol-grown biomass has shown relatively high activity towards 3-chlorocatechol. Based on sequences of the N terminus and tryptic peptides of this enzyme, degenerate PCR primers were now designed and used for cloning of the respective gene from genomic DNA of strain 1CP. A 9.5-kb fragment containing nine open reading frames was obtained on pROP1. Besides other genes, a gene cluster consisting of four chlorocatechol catabolic genes was identified. As judged by sequence similarity and correspondence of predicted N termini with those of purified enzymes, the open reading frames correspond to genes for a second chlorocatechol 1,2-dioxygenase (ClcA2), a second chloromuconate cycloisomerase (ClcB2), a second dienelactone hydrolase (ClcD2), and a muconolactone isomerase-related enzyme (ClcF). All enzymes of this new cluster are only distantly related to the known chlorocatechol enzymes and appear to represent new evolutionary lines of these activities. UV overlay spectra as well as high-pressure liquid chromatography analyses confirmed that 2-chloro-
cis
,
cis
-muconate is transformed by ClcB2 to 5-chloromuconolactone, which during turnover by ClcF gives
cis
-dienelactone as the sole product.
cis
-Dienelactone was further hydrolyzed by ClcD2 to maleylacetate. ClcF, despite its sequence similarity to muconolactone isomerases, no longer showed muconolactone-isomerizing activity and thus represents an enzyme dedicated to its new function as a 5-chloromuconolactone dehalogenase. Thus, during 3-chlorocatechol degradation by
R. opacus
1CP, dechlorination is catalyzed by a muconolactone isomerase-related enzyme rather than by a specialized chloromuconate cycloisomerase.