bluuebunny/crossref_metadata_2025 huggingface dataset:
Omeprazole-Induced Intractable Cough
Authors: Howaizi Mehran , Delafosse Christian
Published: September 2003

OBJECTIVE:

To report a case of chronic, persistent cough induced by omeprazole therapy.

CASE SUMMARY:

A 42-year-old white woman presented with chronic, persistent cough after omeprazole initiation for treatment of postoperative heartburn. The cough was permanent, dry, and exhausting and worsened at night. Omeprazole therapy was continued for 4 months because the persistent cough was thought to be related to gastroesophageal reflux disease (GERD). However, no cause of persistent, chronic cough was identified. After omeprazole discontinuation, the cough resolved.

DISCUSSION:

The most common causes of chronic cough in nonsmokers of all ages are postnasal drip syndrome, asthma, and GERD. However, persistent cough without bronchospasm or other pulmonary involvement may occur as a drug adverse effect. According to the US omeprazole package insert, cough is observed as an adverse reaction in 1.1% of patients, although this has not been mentioned in international drug information sources or medical literature. A MEDLINE search (1966–June 2003) using the terms cough, drug related, adverse effects, and omeprazole failed to find any data. In our patient, there was a temporal relationship between cough and medication use, suggesting a causal relationship. An objective causality assessment revealed that the adverse drug reaction was probable. The mechanism is unclear.

CONCLUSIONS:

Chronic, persistent cough may occur as an adverse effect of omeprazole therapy. Clinicians must be aware of this adverse effect to avoid useless and costly tests.
G2 checkpoint targets late replicating DNA
Authors: Campo Del , Samaniego R. , Giménez‐Abián J.F. , Giménez‐Martín G. , López‐Sáez J.F. , Díaz de la Espina S. Moreno , De la Torre C.
Published: October 2003

In the multinucleate cells induced in Allium cepa L. meristems, the nuclei surrounded by the largest cytoplasm environment complete replication earlier (advanced nuclei), but have a longer G2, than the others (delayed nuclei). Thus, all nuclei break down the nuclear envelope and start metaphase simultaneously. The present report shows that this synchronization relies on a checkpoint mechanism. When completion of replication was prevented in the delayed nuclei (due to in vivo 5‐aminouracil feeding initiated when the advanced nuclei were already in G2), the metaphase was also further delayed in the advanced ones. In turn, some of the delayed nuclei overrode the G2 checkpoint (adaptation) and entered into mitosis with broken chromatids (Del Campo et al., 1997). Anoxic UVA (313 nm) irradiation apparently prevents the binding of regulatory proteins to Br‐DNA. The present report shows that late replicating sequences are the targets of the checkpoint signal produced by the still replicating nuclei. This signal delays metaphase in the advanced nuclei, whose DNA is already fully replicated. Thus, when the already replicated sequences of late replicating DNA was modified in the advanced nuclei by bromosubstitution followed by anoxic UVA irradiation, they entered into mitosis without any delay, ignoring the inhibitory signals produced by the still replicating nuclei.
Expression of cell adhesion molecules in the adriamycin‐induced esophageal atresia rat model
Authors: Tugay Melih , Filiz Serdar , Dalçik Hakki , Güvenç B. Haluk , Dalçik Cannur , Korkmaz Mevlit , Sozubir Selami
Published: October 2003

Cell adhesion molecules are well‐known membrane glycoproteins widely expressed during embryonic development that play a crucial role in cell division, migration and differentiation. We investigated the cell—matrix relationship using N‐CAM and pan‐cadherin adhesion molecules in the adriamycin‐induced esophageal atresia (EA) rat model in the hope of finding a clue to the mechanisms of this unique anomaly.

Time‐mated pregnant Sprague—Dawley rats were given either saline or adriamycin on days 8 and 9 of gestation. Embryos were harvested on the 18th day of gestation. Esophageal specimens obtained from adriamycin‐exposed embryos with (EA+) or without esophageal atresia (EA−) and from saline‐exposed embryos were immunostained with N‐CAM and pan‐cadherin primary antisera.

The esophageal specimens from control and EA− groups revealed similar immunostaining properties: weak N‐CAM and pan‐cadherin immunoreactivity. In contrast, the EA+ group showed intense immunoreactivity.

Our study demonstrated an increased synthesis of N‐CAM and pan‐cadherin in the epithelial cells of the atretic esophagus and trachea. These results suggest that embryonic cell—cell and cell—matrix interactions may play a crucial role in the development of adriamycin‐induced EA.
Leader Political Skill and Team Performance
Authors: Ahearn Kathleen K. , Ferris Gerald R. , Hochwarter Wayne A. , Douglas Ceasar , Ammeter Anthony P.
Published: October 2003

The present study investigates the impact of the political skill of leaders on team performance. More specifically, this study examined the role of leader political skill in the performance of casework teams in a large state child welfare system. Team performance was operationalized as “permanency rate,” or the successful placement of children into legally final living arrangements (i.e., adoption, successor guardianship, or return to natural parents). After controlling for several contextually important factors (i.e., average caseload, average age of children served, average number of team placements, team member experience, leader experience, and team empowerment), leader political skill was found to explain a significant proportion of variance in team performance scores. Implications of these results, as well as directions for future research, are discussed.
The Devil is in the Details: Converting Good Research into Publishable Articles
Authors: Feldman Daniel C.
Published: October 2003

The number one problem with abstracts is too much approach, not enough arrival. Sometimes abstracts are so generically written that they do not pique the reviewers’ interest at all. Many read like this: “Topic A is increasingly important in the global marketplace. Drawing upon the literatures in B, C, D, and E, we present a general framework for understanding A. Data were collected from a wide variety of firms and several interesting patterns of findings emerged. The article concludes with a discussion of future research directions and implications for management practice.” Abstracts are your first chance to make a positive impression on reviewers; try to give the readers some concrete information to get them excited about your work.

There’s nothing mystical about number of words in an abstract. Nonetheless, a good rule of thumb is one-half to two-thirds of a page. Try to include your key words at the end of your abstract.
Expression and regulation of NDRG2 (N‐myc downstream regulated gene 2) during the differentiation of dendritic cells
Authors: Choi Seung-Chul , Kim Kwang Dong , Kim Jong-Tae , Kim Jae-Wha , Yoon Do-Young , Choe Yong-Kyung , Chang Yong-Suk , Paik Sang-Gi , Lim Jong-Seok
Published: October 2003

We searched for genes with expressions specific to human monocyte‐derived dendritic cells (DCs) using differential display reverse transcription‐polymerase chain reaction, and found that N‐myc downstream regulated gene 2 (NDRG2), a member of a new family of differentiation‐related genes, was expressed in DCs. While DCs derived from CD34+ progenitor cells also showed strong NDRG2 expression, the corresponding mRNA expression was absent in other cell lines including monocytes, B cells, and NK cells. The inhibition of DC differentiation by dexamethasone or vitamin D3 treatment down‐regulated the expression of the NDRG2 gene in DCs. In addition, gene expression was induced in a myelomonocytic leukemia cell line, which is capable of differentiating into DCs in cytokine‐conditioned culture. The level of NDRG2 gene expression in DCs was significantly higher than that of other members of the NDRG gene family. Finally, in contrast to the stable NDRG2 expression in CD40‐stimulated DCs, the induction of DC maturation by lipopolysaccharide (LPS) resulted in the down‐regulation of NDRG2 gene expression. This down‐regulation is likely to be due to a modification and subsequent destabilization of NDRG2 mRNA, because co‐treating with actinomycin D and LPS significantly blocked this LPS effect. Taken together, our results indicate that NDRG2 is expressed during the differentiation of DCs, and that NDRG2 gene expression is differentially regulated by maturation‐inducing stimuli.
Determinants of platelet responsiveness to nitric oxide in patients with chronic heart failure
Authors: Anderson R.A. , Ellis G.R. , Chirkov Y.Y. , Holmes A.S. , Payne N. , Blackman D.J. , Jackson S.K. , Lewis M.J. , Horowitz J.D. , Frenneaux M.P.
Published: October 2003

Congestive heart failure (CHF) is associated with oxidative stress. Platelet responsiveness to nitric oxide (NO) donors, are impaired in patients with angina pectoris, possibly by increasing oxidative stress. We investigated the occurrence of platelet resistance to NO in patients, with ischaemic or non‐ischaemic cardiomyopathy compared with normal subjects. Anti‐aggregatory effects of sodium nitroprusside (SNP), oxidative stress and whole blood superoxide anion content were determined, with correlates of responsiveness to SNP. Inhibition of platelet aggregation by SNP was 65.4±3.55% in controls and 59.3±4.1% in CHF (P=ns) despite increased oxidative stress and post‐aggregation O2− in CHF patients. However, subsets of CHF patients have NO‐resistant platelets: this is associated with increasing age and/or increased oxidative stress (both p<0.05).
Is the Childbirth Experience Improved by a Birth Plan?
Authors: Lundgren Ingela , Berg Marie , Lindmark Gunilla
Published: October 2003

From antenatal clinics in Sweden, 271 women were recruited after week 33 of pregnancy and given a questionnaire designed to assess their attitudes and feelings about the coming childbirth. Thereafter, they formulated a birth plan. The midwife in attendance at the birth was able to refer to this plan. Women who followed this program were compared with women from the same clinics who were asked to complete a questionnaire during the first postpartum week to assess their birth experience. A questionnaire at the end of pregnancy, followed by a birth plan, was not effective in improving women's experiences of childbirth. In the birth plan group, women gave significantly lower scores for the relationship to the first midwife they met during delivery, with respect to listening and paying attention to needs and desires, support, guiding, and respect. Although a birth plan did not improve the experience of childbirth in the overall group, there may be beneficial effects with regard to fear, pain, and concerns about the newborn for certain subgroups of women.
CEU Maternal Serologic Screening for Toxoplasmosis
Authors: Pinard Jennifer A. , Leslie Nan S. , Irvine Pamela J.
Published: October 2003

Congenital toxoplasmosis is a rare, but potentially serious, problem during pregnancy. Toxoplasmosis is caused by a protozoal parasite that can be found in warm‐blooded animals (including humans); dried cat feces, contaminated soil, or contaminated water; and raw or undercooked meat containing infective tissue cysts. Although cats play a role in the epidemiology of the disease, there is no statistical correlation between toxoplasmosis infection and cat ownership. Toxoplasmosis can be transmitted to the fetus in utero through transplacental transmission. Both the incidence of placental transmission and severity of congenital disease depend on gestational age at which maternal seroconversion occurs. Although transmission rates from mother to fetus tend to be low early in pregnancy, fetal disease severity is highest when the fetus is infected early in gestation. Serological tests to determine maternal seroconversion are available, but their use can pose ethical and practical dilemmas. Universal maternal screening is not currently warranted in the United States because disease prevalence is low.
Fatty Acid Biosynthesis in Mitochondria of Grasses: Malonyl-Coenzyme A Is Generated by a MitochondrialLocalized Acetyl-Coenzyme A Carboxylase
Authors: Focke Manfred , Gieringer Ellen , Schwan Sabine , Jänsch Lothar , Binder Stefan , Braun Hans-Peter
Published: October 2003

We present biochemical evidence for the occurrence of a 250-kD multifunctional acetyl-coenzyme A carboxylase in barley (Hordeum vulgare) mitochondria. Organelles from 6-d-old barley seedlings were purified by differential centrifugation and Percoll density gradient centrifugation. Upon analysis by two-dimensional Blue-native (BN)/SDS-PAGE, an abundant 250-kD protein can be visualized, which runs at 500 kD on the native gel dimension. A similar 500-kD complex is present in etioplasts from barley. The mitochondrial 250-kD protein is biotinylated as indicated by specific reaction with an antibody directed against biotin. Peptide sequence analysis by electrospray ionization tandem mass spectrometry of the 250-kD proteins from both organellar fractions revealed amino acid sequences that are 100% identical to plastidic acetyl-coenzyme A carboxylase from wheat (Triticum aestivum). The 500-kD complex was also detected in wheat mitochondria, but is absent in mitochondrial fractions from Arabidopsis. Specific acetyl-coenzyme A carboxylation activity in barley mitochondria is higher than in etioplasts, suggesting an important role of mitochondria in fatty acid biosynthesis. Functional implications are discussed.
Plasma Membrane Aquaporins Are Involved in Winter Embolism Recovery in Walnut Tree
Authors: Sakr Soulaiman , Alves Georges , Morillon Raphaël , Maurel Karine , Decourteix Mélanie , Guilliot Agnès , Fleurat-Lessard Pierrette , Julien Jean-Louis , Chrispeels Maarten J.
Published: October 2003

In perennial plants, freeze-thaw cycles during the winter months can induce the formation of air bubbles in xylem vessels, leading to changes in their hydraulic conductivity. Refilling of embolized xylem vessels requires an osmotic force that is created by the accumulation of soluble sugars in the vessels. Low water potential leads to water movement from the parenchyma cells into the xylem vessels. The water flux gives rise to a positive pressure essential for the recovery of xylem hydraulic conductivity. We investigated the possible role of plasma membrane aquaporins in winter embolism recovery in walnut (Juglans regia). First, we established that xylem parenchyma starch is converted to sucrose in the winter months. Then, from a xylem-derived cDNA library, we isolated two PIP2 aquaporin genes (JrPIP2,1 and JrPIP2,2) that encode nearly identical proteins. The water channel activity of the JrPIP2,1 protein was demonstrated by its expression in Xenopus laevis oocytes. The expression of the two PIP2 isoforms was investigated throughout the autumn-winter period. In the winter period, high levels of PIP2 mRNA and corresponding protein occurred simultaneously with the rise in sucrose. Furthermore, immunolocalization studies in the winter period show that PIP2 aquaporins were mainly localized in vessel-associated cells, which play a major role in controlling solute flux between parenchyma cells and xylem vessels. Taken together, our data suggest that PIP2 aquaporins could play a role in water transport between xylem parenchyma cells and embolized vessels.
Nucleosome Position-Dependent and -Independent Activation of
HIS7
Expression in
Saccharomyces cerevisiae
by Different Transcriptional Activators
Authors: Valerius Oliver , Brendel Cornelia , Wagner Claudia , Krappmann Sven , Thoma Fritz , Braus Gerhard H.
Published: October 2003

ARO4
and
HIS7
are two tandemly orientated genes of
Saccharomyces cerevisiae
that are transcribed into the same direction. The
ARO4
terminator and the
HIS7
promoter regions are sensitive to
Micrococcus
nuclease (Mnase) and separated by a positioned nucleosome. The
HIS7
promoter is target for the transcription factors Gcn4p and Bas1p/Bas2p that activate its transcription upon amino acid starvation and purine limitation, respectively. Activation of the
HIS7
gene by Gcn4p overexpression but not by Bas1p/Bas2p releases an ordered nucleosome distribution to yield increased Mnase sensitivity throughout the intergenic region. This remodeling is
SNF2
dependent but mostly
GCN5
independent. Accordingly,
SNF2
is necessary for the Gcn4p-mediated transcriptional activation of the
HIS7
gene.
GCN5
is required for activation upon adenine limitation by Bas1p/Bas2p. Our data suggest that activation of
HIS7
transcription by Gcn4p and Bas1p/Bas2p is supported by a nucleosome position-dependent and -independent mechanism, respectively. Whereas Gcn4p activation causes Swi/Snf-mediated remodeling of the nucleosomal architecture at the
HIS7
promoter, the Bas1p/Bas2p complex presumably activates in combination with Gcn5p-dependent histone acetylation.
Copper Response Element and Crr1-Dependent Ni
2+
-Responsive Promoter for Induced, Reversible Gene Expression in
Chlamydomonas reinhardtii
Authors: Quinn Jeanette M. , Kropat Janette , Merchant Sabeeha
Published: October 2003

The
Cpx1
and
Cyc6
genes of
Chlamydomonas reinhardtii
are activated in copper-deficient cells via a signal transduction pathway that requires copper response elements (CuREs) and a copper response regulator defined by the
CRR1
locus. The two genes can also be activated by provision of nickel or cobalt ions in the medium. The response to nickel ions requires at least one CuRE and also
CRR1
function, suggesting that nickel interferes with a component in the nutritional copper signal transduction pathway. Nickel does not act by preventing copper uptake/utilization because (i) holoplastocyanin formation is unaffected in Ni
2+
-treated cells and (ii) provision of excess copper cannot reverse the Ni-dependent activation of the target genes. The CuRE is sufficient for conferring Ni-responsive expression to a reporter gene, which suggests that the system has practical application as a vehicle for inducible gene expression. The inducer can be removed either by replacing the medium or by chelating the inducer with excess EDTA, either of which treatments reverses the activation of the target genes.
Green fluorescent protein‐labeled mapping of neural stem cells migrating towards damaged areas in the adult central nervous system
Authors: Zhou Chang , Wen Zhe‐Xing , Wang Zhi‐Ping , Guo Xing , Shi Dong‐Mei , Zuo Huan‐Cong , Xie Zuo‐Ping
Published: October 2003

Neural stem cells, which are clonogenic cells with multilineage differentiation properties from regions of the fetal brain, cortex and hippocampus, are currently considered as powerful candidates for cell replacement therapy in neurodegenerative disorders, such as Parkinson's disease. A key issue is whether stem cells can survive, migrate and differentiate following transplantation into the adult CNS. Here, enhanced green fluorescent protein plasmid electroporation‐transfected neural stem cells from the fetal cortex were grafted into the striatum of a rat model of Parkinson's disease. We found most of the grafted cells could survive in the adult parkinsonian rat brain and migrated towards damaged areas, while they moved randomly in the normal brain. Several grafted cells differentiated into neurons.
Complexity Absorption and Performance: A Structural Analysis of Acute-Care Hospitals
Authors: Walters Bruce A. , Bhuian Shahid N.
Published: October 2003

This study assesses the degree to which a complexity absorption response enhances performance in an industry increasingly described as highly complex: acute-care hospitals. Business-level strategy, organizational structure, and analytical comprehensiveness are viewed as mechanisms through which executives can increase internal complexity. A case is made that hospitals are well served to pursue a hybrid (or combination) strategy, employ an organic structure, and engage in a high degree of information acquisition and use. In keeping with a complexity absorption view, results indicate that these elements generally exhibit stronger associations with performance as dynamism increases.
Investigation of the functional relevance of the catalytically important Glu28 in family 51 arabinosidases
Authors: Ferchichi Mounir , Rémond Caroline , Simo Roselyne , O’Donohue Michael J.
Published: October 2003

The α‐L‐arabinofuranosidase (AbfD3) from Thermobacillus xylanilyticus is a family 51 glycosyl hydrolase. According to classification hierarchy, family 51 belongs to clan GH‐A. While the major GH‐A motifs, the catalytic acid‐base and nucleophile, are conserved in AbfD3, a third catalytically important residue (Glu28) does not appear to be analogous to any known GH‐A motif. To evaluate the importance of Glu28, bioinformatics analyses and site‐saturation mutagenesis were performed. The results indicate that Glu28 forms part of a family 51 arabinosidase motif which might be functionally homologous to a conserved N‐terminal motif found in exo‐acting enzymes from families 1 and 5. Importantly, the data reveal that Glu28 is a key determinant of substrate recognition in the −1 subsite, where it may also play an important role in water‐mediated deglycosylation of the glycosyl–enzyme covalent intermediate.
Electrostatic interactions across the dimer–dimer interface contribute to the pH‐dependent stability of a tetrameric malate dehydrogenase
Authors: Bjørk Alexandra , Mantzilas Dimitrios , Sirevåg Reidun , Eijsink Vincent G.H.
Published: October 2003

Malate dehydrogenase (MDH) from the moderately thermophilic bacterium Chloroflexus aurantiacus (CaMDH) is a tetrameric enzyme, while MDHs from mesophilic bacteria usually are dimers. Using site‐directed mutagenesis, we show here that a network of electrostatic interactions across the extra dimer–dimer interface in CaMDH is important for thermal stability and oligomeric integrity. Stability effects of single point mutations (E25Q, E25K, D56N, D56K) varied from −1.2°C to −26.8°C, and depended strongly on pH. Gel‐filtration experiments indicated that the 26.8°C loss in stability observed for the D56K mutant at low pH was accompanied by a shift towards a lower oligomerization state.
The critical structural role of a highly conserved histidine residue in group II amino acid decarboxylases
Authors: Capitani Guido , Tramonti Angela , Bossa Francesco , Grütter Markus G. , De Biase Daniela
Published: October 2003

Glutamate decarboxylase is a pyridoxal 5′‐phosphate (PLP)‐dependent enzyme, belonging to the subset of PLP‐dependent decarboxylases classified as group II. Site‐directed mutagenesis of Escherichia coli glutamate decarboxylase, combined with analysis of the crystal structure, shows that a histidine residue buried in the protein core is critical for correct folding. This histidine is strictly conserved in the PF00282 PFAM family, which includes the group II decarboxylases. A similar role is proposed for residue Ser269, also highly conserved in this group of enzymes, as it provides one of the interactions stabilising His241.
Genomic organization and transcription of the human retinol dehydrogenase 10 (RDH10) gene
Authors: Picozzi P. , Marozzi A. , Fornasari D. , Benfante R. , Barisani D. , Meneveri R. , Ginelli E.
Published: October 2003

A cDNA clone up‐regulated in hydraulic lung edema in rabbit showed high similarity with human RDH10 mRNA, which encodes a protein involved in retinoic acid metabolism. We defined the organization of the human gene, which includes a unique transcriptional start site, a coding region with six translated exons and a 3′ untranslated region containing at least two used polyadenylation sites. The two poly(A) signals are responsible for the production of the 3 and 4 kb RDH10 mRNA isoforms detected in several human tissues and cell lines.
Polygalacturonase β-Subunit Antisense Gene Expression in Tomato Plants Leads to a Progressive Enhanced Wound Response and Necrosis in Leaves and Abscission of Developing Flowers
Authors: Orozco-Cárdenas Martha L. , Ryan Clarence A.
Published: October 2003

Tomato (Lycopersicon esculentum var. Better Boy) plants were transformed with a tomato leaf wound-inducible polygalacturonase (PG) β-subunit gene in the antisense orientation (PGβS-AS) under the control of the cauliflower mosaic virus 35S promoter. The leaves of the transgenic plants exhibited small localized lesions, which eventually enlarged and spread throughout the entire surfaces of the leaves, resulting in cell death. The same lesions were also observed in the peduncle of developing flowers, extending to the whole flower causing abscission, resulting in a sterile phenotype. Leaves of transgenic plants exhibited elevated levels of PG activity, hydrogen peroxide, and enhanced defense signaling in response to wounding and elicitor treatment. The defense signaling increased was accompanied by an increased resistance toward tobacco hornworm (Manduca sexta) larvae. The cumulative results suggest that in the absence of the β-subunit protein in tomato leaves, an increase in PG activity occurred that led to an enhanced wound response, the formation of lesions leading to severe necrosis, and an abscission of developing flowers.
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

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

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.
How Subgroup Interests and Reputations Moderate the Effect of Organizational Identification on Cooperation
Authors: Polzer Jeffrey T.
Published: October 2003

Two experiments tested the effects of organizational identification on individual decisions to cooperate. These decisions occurred in the context of a nested social dilemma in which individuals, subgroups, and the larger collective each held distinct and incompatible interests. In Study 1, when the two subgroups in the dilemma were from different real organizations, higher organizational identification caused lower cooperation with the collective (and higher cooperation with the subgroup) when the opposing organization had a purportedly individualistic culture and reputation. The results of Study 2 supported this interpretation by showing that organizational identification had a negative effect on collective cooperation, and a corresponding positive effect on subgroup cooperation, when decision makers perceived the opposing department to have an individualistic reputation. I discuss the implications of these results for organizations that try to elicit cooperation by fostering members’ organizational identification.
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

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.
Structural and mechanistic insight from high resolution structures of archaeal rhodopsins
Authors: Landau Ehud M , Pebay-Peyroula Eva , Neutze Richard
Published: October 2003

Lipidic cubic phase‐grown crystals yielded high resolution structures of a number of archaeal retinal proteins, the molecular mechanisms of which are being revealed as structures of photocycle intermediates become available. The structural basis for bacteriorhodopsin's mechanism of proton pumping is discussed, revealing a well‐synchronized sequence of molecular events. Comparison with the high resolution structures of the halide pump halorhodopsin, as well as with the receptor sensory rhodopsin II, illustrates how small and localized structural changes result in functional divergence. Fundamental principles of energy transduction and sensory reception in the archaeal rhodopsins, which may have relevance to other systems, are discussed.
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

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

ADP-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

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

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

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

Neurotransmitter 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

Vanadate 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

The 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.
Formation of glucosylceramide and sterol glucoside by a UDP‐glucose‐dependent glucosylceramide synthase from cotton expressed in Pichia pastoris
Authors: Hillig Inga , Leipelt Martina , Ott Claudia , Zähringer Ulrich , Warnecke Dirk , Heinz Ernst
Published: October 2003

In plants, glucosylceramide (GlcCer) biosynthesis is poorly understood. Previous investigations suggested that sterol glucoside (SG) acts as the actual glucose donor for the plant GlcCer synthase (GCS). We addressed this question by generating a Pichia pastoris double mutant devoid of GlcCer and SG. This mutant was used for heterologous expression of the plant GCS. The activity of the GCS resulted in the accumulation of GlcCer and, surprisingly, a small proportion of SG. The synthesis of GlcCer in the transformed double mutant shows that the GCS is SG‐independent, while the detection of SG suggests that in addition to the sterol glucosyltransferase, also the GCS may contribute in planta to SG biosynthesis.
Ospdr9, which encodes a PDR‐type ABC transporter, is induced by heavy metals, hypoxic stress and redox perturbations in rice roots1
Authors: Moons Ann
Published: October 2003

Little is known about the role of pleiotropic drug resistance (PDR)‐type ATP‐binding (ABC) proteins in plant responses to environmental stresses. We characterised ospdr9, which encodes a rice ABC protein with a reverse (ABC‐TMS6)2 configuration. Polyethylene glycol and the heavy metals Cd (20 μM) and Zn (30 μM) rapidly and markedly induced ospdr9 in roots of rice seedlings. Hypoxic stress also induced ospdr9 in rice roots, salt stress induced ospdr9 at low levels but cold and heat shock had no effect. The plant growth regulator jasmonic acid, the auxin α‐naphthalene acetic acid and the cytokinin 6‐benzylaminopurine triggered ospdr9 expression. The antioxidants dithiothreitol and ascorbic acid rapidly and markedly induced ospdr9 in rice roots; the strong oxidant hydrogen peroxide also induced ospdr9 but at three times lower levels. The results suggested that redox changes may be involved in the abiotic stress response regulation of ospdr9 in rice roots.
Aquaporin water channels: molecular mechanisms for human diseases1
Authors: Agre Peter , Kozono David
Published: October 2003

Although water is the major component of all biological fluids, the molecular pathways for water transport across cell membranes eluded identification until the discovery of the aquaporin family of water channels. The atomic structure of mammalian AQP1 illustrates how this family of proteins is freely permeated by water but not protons (hydronium ions, H3O+). Definition of the subcellular sites of expression predicted their physiological functions and potential clinical disorders. Analysis of several human disease states has confirmed that aquaporins are involved in multiple different illnesses including abnormalities of kidney function, loss of vision, onset of brain edema, starvation, and arsenic toxicity.