bluuebunny/crossref_metadata_2025 huggingface dataset:
Dissecting Defense-Related and Developmental Transcriptional Responses of Maize during Ustilago maydis Infection and Subsequent Tumor Formation
Authors: Basse Christoph W.
Published: June 2005

Infection of maize (Zea mays) plants with the smut fungus Ustilago maydis triggers the formation of tumors on aerial parts in which the fungal life cycle is completed. A differential display screen was performed to gain insight into transcriptional changes of the host response. Some of the genes strongly up-regulated in tumors showed a pronounced developmental expression pattern with decreasing transcript levels from basal to apical shoot segments, suggesting that U. maydis has the capacity to extend the undifferentiated state of maize plants. Differentially expressed genes implicated in secondary metabolism were Bx1, involved in biosynthesis of the cyclic hydroxamic acid 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one, and a novel putative sesquiterpene cyclase gene U. maydis induced (Umi)2. Together with the up-regulation of Umi11 encoding a cyclotide-like protein this suggests a nonconventional induction of plant defenses. Explicitly, U. maydis was resistant to 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one but susceptible to its benzoxazolinone derivative 6-methoxy-2-benzoxazolinone. Infection studies of isolated leaves with U. maydis and Colletotrichum graminicola provided evidence for coregulation of Umi2 and PR-1 gene expression, with mRNA levels strongly determined by the extent of fungal colonization within tissue. However, in contrast to Umi2, transcript levels of PR-1 remained low in plants infected with wild-type U. maydis but were 8-fold elevated upon infection with an U. maydis mutant strongly attenuated in pathogenic development. This suggests that U. maydis colonization in planta suppresses a classical defense response. Furthermore, comparative expression analysis uncovered distinct transcriptional programs operating in the host in response to fungal infection and subsequent tumor formation.
A Second Kazal-Like Protease Inhibitor from Phytophthora infestans Inhibits and Interacts with the Apoplastic Pathogenesis-Related Protease P69B of Tomato
Authors: Tian Miaoying , Benedetti Brett , Kamoun Sophien
Published: June 2005

The plant apoplast forms a protease-rich environment in which proteases are integral components of the plant defense response. Plant pathogenic oomycetes, such as the potato (Solanum tuberosum) and tomato (Lycopersicon esculentum) pathogen Phytophthora infestans, secrete a diverse family of serine protease inhibitors of the Kazal family. Among these, the two-domain EPI1 protein was shown to inhibit and interact with the pathogenesis-related protein P69B subtilase of tomato and was implicated in counter-defense. Here, we describe and functionally characterize a second extracellular protease inhibitor, EPI10, from P. infestans. EPI10 contains three Kazal-like domains, one of which was predicted to be an efficient inhibitor of subtilisin A by an additivity-based sequence to reactivity algorithm (Laskowski algorithm). The epi10 gene was up-regulated during infection of tomato, suggesting a potential role during pathogenesis. Recombinant EPI10 specifically inhibited subtilisin A among the major serine proteases, and inhibited and interacted with P69B subtilase of tomato. The finding that P. infestans evolved two distinct and structurally divergent protease inhibitors to target the same plant protease suggests that inhibition of P69B could be an important infection mechanism for this pathogen.
FesM, a Membrane Iron-Sulfur Protein, Is Required for Cyclic Electron Flow around Photosystem I and Photoheterotrophic Growth of the Cyanobacterium Synechococcus sp. PCC 7002
Authors: Xu Dongyi , Liu Xianwei , Zhao Jiao , Zhao Jindong
Published: June 2005

While it is known that cyclic electron flow around photosystem I is an important pathway of photosynthetic electron transfer for converting light energy to chemical energy, some components of cyclic electron flow remain to be revealed. Here, we show that fesM, encoding a novel membrane iron-sulfur protein, is essential to cyclic electron flow in the cyanobacterium Synechococcus sp. PCC 7002. The FesM protein is predicted to have a cAMP-binding domain, an NtrC-like domain, a redox sensor motif, and an iron-sulfur (4Fe-4S) motif. Deletion of fesM (fesM-D) led to an inability for Synechococcus cells to grow in the presences of glycerol and 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Photoheterotrophic growth was restored by a complete fesM gene present on a replicable plasmid. A mutant fesM gene encoding a truncated FesM protein lacking the cAMP domain failed to restore the phenotype, suggesting this domain is important to the function of FesM. Measurements of reduction of P700+ and the redox state of interphotosystem electron carriers showed that cells had a slower rate of respiratory electron donation to the interphotosystem electron transport chain, and cyclic electron flow around photosystem I in fesM-D was impaired, suggesting that FesM is a critical protein for respiratory and cyclic electron flow. Phosphatase fusion analysis showed that FesM contains nine membrane-spanning helices, and all functional domains of FesM are located on the cytoplasmic face of the thylakoid membranes.
Water Uptake and Distribution in Germinating Tobacco Seeds Investigated in Vivo by Nuclear Magnetic Resonance Imaging
Authors: Manz Bertram , Müller Kerstin , Kucera Birgit , Volke Frank , Leubner-Metzger Gerhard
Published: June 2005

The regulation of water uptake of germinating tobacco (Nicotiana tabacum) seeds was studied spatially and temporally by in vivo 1H-nuclear magnetic resonance (NMR) microimaging and 1H-magic angle spinning NMR spectroscopy. These nondestructive state-of-the-art methods showed that water distribution in the water uptake phases II and III is inhomogeneous. The micropylar seed end is the major entry point of water. The micropylar endosperm and the radicle show the highest hydration. Germination of tobacco follows a distinct pattern of events: rupture of the testa is followed by rupture of the endosperm. Abscisic acid (ABA) specifically inhibits endosperm rupture and phase III water uptake, but does not alter the spatial and temporal pattern of phase I and II water uptake. Testa rupture was associated with an increase in water uptake due to initial embryo elongation, which was not inhibited by ABA. Overexpression of β-1,3-glucanase in the seed-covering layers of transgenic tobacco seeds did not alter the moisture sorption isotherms or the spatial pattern of water uptake during imbibition, but partially reverted the ABA inhibition of phase III water uptake and of endosperm rupture. In vivo 13C-magic angle spinning NMR spectroscopy showed that seed oil mobilization is not inhibited by ABA. ABA therefore does not inhibit germination by preventing oil mobilization or by decreasing the water-holding capacity of the micropylar endosperm and the radicle. Our results support the proposal that different seed tissues and organs hydrate at different extents and that the micropylar endosperm region of tobacco acts as a water reservoir for the embryo.
In Vivo Respiratory Metabolism of Illuminated Leaves
Authors: Tcherkez Guillaume , Cornic Gabriel , Bligny Richard , Gout Elizabeth , Ghashghaie Jaleh
Published: June 2005

Day respiration of illuminated C3 leaves is not well understood and particularly, the metabolic origin of the day respiratory CO2 production is poorly known. This issue was addressed in leaves of French bean (Phaseolus vulgaris) using 12C/13C stable isotope techniques on illuminated leaves fed with 13C-enriched glucose or pyruvate. The 13CO2 production in light was measured using the deviation of the photosynthetic carbon isotope discrimination induced by the decarboxylation of the 13C-enriched compounds. Using different positional 13C-enrichments, it is shown that the Krebs cycle is reduced by 95% in the light and that the pyruvate dehydrogenase reaction is much less reduced, by 27% or less. Glucose molecules are scarcely metabolized to liberate CO2 in the light, simply suggesting that they can rarely enter glycolysis. Nuclear magnetic resonance analysis confirmed this view; when leaves are fed with 13C-glucose, leaf sucrose and glucose represent nearly 90% of the leaf 13C content, demonstrating that glucose is mainly directed to sucrose synthesis. Taken together, these data indicate that several metabolic down-regulations (glycolysis, Krebs cycle) accompany the light/dark transition and emphasize the decrease of the Krebs cycle decarboxylations as a metabolic basis of the light-dependent inhibition of mitochondrial respiration.
The roothairless1 Gene of Maize Encodes a Homolog of sec3, Which Is Involved in Polar Exocytosis
Authors: Wen Tsui-Jung , Hochholdinger Frank , Sauer Michaela , Bruce Wesley , Schnable Patrick S.
Published: June 2005

The roothairless1 (rth1) mutant is impaired in root hair elongation and exhibits other growth abnormalities. Unicellular root hairs elongate via localized tip growth, a process mediated by polar exocytosis of secretory vesicles. We report here the cloning of the rth1 gene that encodes a sec3 homolog. In yeast (Saccharomyces cerevisiae) and mammals, sec3 is a subunit of the exocyst complex, which tethers exocytotic vesicles prior to their fusion. The cloning of the rth1 gene associates the homologs of exocyst subunits to an exocytotic process in plant development and supports the hypothesis that exocyst-like proteins are involved in plant exocytosis. Proteomic analyses identified four proteins that accumulate to different levels in wild-type and rth1 primary roots. The preferential accumulation in the rth1 mutant proteome of a negative regulator of the cell cycle (a prohibitin) may at least partially explain the delayed development and flowering of the rth1 mutant.
Flowering of the Grass Lolium perenne. Effects of Vernalization and Long Days on Gibberellin Biosynthesis and Signaling
Authors: MacMillan Colleen P. , Blundell Cheryl A. , King Rod W.
Published: June 2005

Almost 50 years ago, it was shown that gibberellin (GA) applications caused flowering in species normally responding to cold (vernalization) and long day (LD). The implication that GAs are involved with vernalization and LD responses is examined here with the grass Lolium perenne. This species has an obligatory requirement for exposure to both vernalization and LD for its flowering (inflorescence initiation). Specific effects of vernalization or LD on GA synthesis, content, and action have been documented using four treatment pairs: nonvernalized or vernalized plants exposed to short days (SDs) or LDs. Irrespective of vernalization status, exposure to two LDs increased expression of L. perenne GA 20-oxidase-1 (LpGA20ox1), a critical GA biosynthetic gene, with endogenous GAs increasing by up to 5-fold in leaf and shoot. In parallel, LD led to degradation of a DELLA protein, SLENDER (within 48 h of LD or within 2 h of GA application). There was no effect on GA catabolism or abscisic acid content. Loss of SLENDER, which is a repressor of GA signaling, confirms the physiological relevance of increased GA content in LD. For flowering, applied GA replaced the need for LD but not that for vernalization. Thus, GAs may be an LD, leaf-sourced hormonal signal for flowering of L. perenne. By contrast, vernalization had little impact on GA or SLENDER levels or on SLENDER degradation following GA application. Thus, although vernalization and GA are both required for flowering of L. perenne, GA signaling is independent of vernalization that apparently impacts on unrelated processes.
Molecular Cloning of a β-Galactosidase from Radish That Specifically Hydrolyzes β-(1→3)- and β-(1→6)-Galactosyl Residues of Arabinogalactan Protein
Authors: Kotake Toshihisa , Dina Soraya , Konishi Tomoyuki , Kaneko Satoshi , Igarashi Kiyohiko , Samejima Masahiro , Watanabe Yoko , Kimura Kazumasa , Tsumuraya Yoichi
Published: June 2005

A basic β-galactosidase with high specificity toward β-(1→3)- and β-(1→6)-galactosyl residues was cloned from radish (Raphanus sativus) plants by reverse transcription-PCR. The gene, designated RsBGAL1, contained an open reading frame consisting of 2,532 bp (851 amino acids). It is expressed in hypocotyls and young leaves. RsBGAL1 was highly similar to β-galactosidases having exo-β-(1→4)-galactanase activity found in higher plants and belongs to family 35 of the glycosyl hydrolases. Recombinant RsBGAL1 was expressed in Pichia pastoris and purified to homogeneity. The recombinant enzyme specifically hydrolyzed β-(1→3)- and β-(1→6)-galactooligosaccharides, the same substrates as the native enzyme isolated from radish seeds (Sekimata et al., 1989). It split off about 90% of the carbohydrate moieties of an arabinogalactan protein extracted from radish roots in concerted action with microbial α-l-arabinofuranosidase and β-glucuronidase. These results suggest that RsBGAL1 is a new kind of β-galactosidase with different substrate specificity than other β-galactosidases that exhibit exo-β-(1→4)-galactanase activity. The C-terminal region (9.6 kD) of RsBGAL1 is significantly similar to the Gal lectin-like domain, but this region is not retained in the native enzyme. Assuming posttranslational processing of RsBGAL1 with elimination of the Gal lectin-like domain results in a protein consisting of two subunits with molecular masses of 46 and 34 kD (calculated from the RsBGAL1 gene sequence). This is in good agreement with the SDS-PAGE and matrix-assisted laser desorption/ionization-time-of flight mass spectrometry measurements for subunits of the native enzyme (45 and 34 kD) and may thus partially explain the formation process of the native enzyme.
A Gibberellin-Regulated Calcineurin B in Rice Localizes to the Tonoplast and Is Implicated in Vacuole Function
Authors: Hwang Yong-sic , Bethke Paul C. , Cheong Yong Hwa , Chang Hur-Song , Zhu Tong , Jones Russell L.
Published: June 2005

Many developmental and environmental signals are transduced through changes in intracellular calcium concentrations, yet only a few calcium-binding proteins have been identified in plants. Calcineurin B-like (CBL) proteins are calcium-binding proteins that are thought to function as plant signal transduction elements. RNA profiling using a rice (Oryza sativa cv Nipponbare) oligonucleotide microarray was used to monitor gene expression in de-embryonated rice grains. This analysis showed that a putative rice CBL gene responded to gibberellic acid, but not abscisic acid, treatment. The CBL gene family in rice contains at least 10 genes and these have extensive similarity to the CBLs of Arabidopsis (Arabidopsis thaliana). In yeast (Saccharomyces cerevisiae) two-hybrid assays, rice CBLs interact with the kinase partners of Arabidopsis CBLs. Only one rice CBL gene, OsCBL2, is up-regulated by GA in the aleurone layer. A homolog with 91% sequence identity to OsCBL2 was cloned from barley (Hordeum vulgare cv Himalaya), and designated HvCBL2. We examined the localization and function of OsCBL2 and HvCBL2 in rice and barley aleurone because changes in cytosolic calcium have been implicated in the response of the aleurone cell to GA. Green fluorescent protein translational fusions of OsCBL2 and OsCBL3 were localized to the tonoplast of aleurone cell protein storage vacuoles and OsCBL4-green fluorescent protein was localized to the plasma membrane. Data from experiments using antisense expression of OsCBL2 and HvCBL2 are consistent with a role for OsCBL2 in promoting vacuolation of barley aleurone cells following treatment with GA.
Molecular Characterization of Maize Acetylcholinesterase. A Novel Enzyme Family in the Plant Kingdom
Authors: Sagane Yoshimasa , Nakagawa Tomoyuki , Yamamoto Kosuke , Michikawa Soichi , Oguri Suguru , Momonoki Yoshie S.
Published: June 2005

Acetylcholinesterase (AChE) has been increasingly recognized in plants by indirect evidence of its activity. Here, we report purification and cloning of AChE from maize (Zea mays), thus providing to our knowledge the first direct evidence of the AChE molecule in plants. AChE was identified as a mixture of disulfide- and noncovalently linked 88-kD homodimers consisting of 42- to 44-kD polypeptides. The AChE hydrolyzed acetylthiocholine and propyonylthiocholine, but not S-butyrylthiocholine, and the AChE-specific inhibitor neostigmine bromide competitively inhibited its activity, implying that maize AChE functions in a similar manner as the animal enzyme. However, kinetic analyses indicated that maize AChE showed a lower affinity to substrates and inhibitors than animal AChE. The full-length cDNA of maize AChE gene is 1,471 nucleotides, which encode a protein having 394 residues, including a signal peptide. The deduced amino acid sequence exhibited no apparent similarity with that of the animal enzyme, although the catalytic triad was the same as in the animal AChE. In silico screening indicated that maize AChE homologs are widely distributed in plants but not in animals. These findings lead us to propose that the AChE family, as found here, comprises a novel family of the enzymes that is specifically distributed in the plant kingdom.
Characterization of Heterologous Multigene Operons in Transgenic Chloroplasts. Transcription, Processing, and Translation
Authors: Quesada-Vargas Tania , Ruiz Oscar N. , Daniell Henry
Published: June 2005

The first characterization of transcriptional, posttranscriptional, and translational processes of heterologous operons expressed via the tobacco (Nicotiana tabacum) chloroplast genome is reported here. Northern-blot analyses performed on chloroplast transgenic lines harboring seven different heterologous operons revealed that polycistronic mRNA was the predominant transcript produced. Despite the lack of processing of such polycistrons, large amounts of foreign protein accumulation was observed in these transgenic lines, indicating abundant translation of polycistrons. This is supported by polysome fractionation assays, which allowed detection of polycistronic RNA in lower fractions of the sucrose gradients. These results show that the chloroplast posttranscriptional machinery can indeed detect and translate multigenic sequences that are not of chloroplast origin. In contrast to native transcripts, processed and unprocessed heterologous polycistrons were stable, even in the absence of 3′ untranslated regions (UTRs). Unlike native 5′UTRs, heterologous secondary structures or 5′UTRs showed efficient translational enhancement independent of cellular control. Abundant read-through transcripts were observed in the presence of chloroplast 3′UTRs but they were efficiently processed at introns present within the native operon. Heterologous genes regulated by the psbA (the photosystem II polypeptide D1) promoter, 5′ and 3′UTRs have greater abundance of transcripts than the endogenous psbA gene because transgenes were integrated into the inverted repeat region. Addressing questions about polycistrons, and the sequences required for their processing and transcript stability, are essential in chloroplast metabolic engineering. Knowledge of such factors would enable engineering of foreign pathways independent of the chloroplast complex posttranscriptional regulatory machinery.
Functional Analysis of Arabidopsis Ethylene-Responsive Element Binding Protein Conferring Resistance to Bax and Abiotic Stress-Induced Plant Cell Death
Authors: Ogawa Taro , Pan Ling , Kawai-Yamada Maki , Yu Li-Hua , Yamamura Saburo , Koyama Tomotsugu , Kitajima Sakihito , Ohme-Takagi Masaru , Sato Fumihiko , Uchimiya Hirofumi
Published: June 2005

Arabidopsis (Arabidopsis thaliana) ethylene-responsive element binding protein (AtEBP) gene was isolated as a suppressor of Bax-induced cell death by functional screening in yeast (Saccharomyces cerevisiae). To further examine the cell death suppressive action of AtEBP in plant cells, we established transgenic tobacco (Nicotiana tabacum) plants overexpressing AtEBP as well as transgenic tobacco plants ectopically expressing mouse Bax protein under a dexamethasone-inducible promoter. We prepared the crosses of the selective lines of each transgenic plant, which were evaluated in terms of cell death suppression activity. Results indicate that AtEBP suppressed Bax-induced cell death in tobacco plants, an action also associated with a lowered level of ion leakage. Furthermore, tobacco Bright Yellow-2 cells overexpressing AtEBP conferred resistance to hydrogen peroxide (H2O2) and heat treatments. AtEBP protein localized in the nucleus and functioned as an in vivo transcription activator as confirmed in transient assays and experiments using stable transgenic system. Up-regulation of defense genes was observed in transgenic Arabidopsis plants overexpressing AtEBP. Based on the analysis of mRNA accumulation in ethylene-related mutants, the position of AtEBP in signaling pathway is presented.
CORKSCREW1 Defines a Novel Mechanism of Domain Specification in the Maize Shoot
Authors: Alexander Debbie L. , Mellor E. Anne , Langdale Jane A.
Published: June 2005

In higher plants, determinate leaf primordia arise in regular patterns on the flanks of the indeterminate shoot apical meristem (SAM). The acquisition of leaf form is then a gradual process, involving the specification and growth of distinct domains within the three leaf axes. The recessive corkscrew1 (cks1) mutation of maize (Zea mays) disrupts both leaf initiation patterns in the SAM and domain specification within the mediolateral and proximodistal leaf axes. Specifically, cks1 mutant leaves exhibit multiple midribs and leaf sheath tissue differentiates in the blade domain. Such perturbations are a common feature of maize mutants that ectopically accumulate KNOTTED1-like homeobox (KNOX) proteins in leaf tissue. Consistent with this observation, at least two knox genes are ectopically expressed in cks1 mutant leaves. However, ectopic KNOX proteins cannot be detected. We therefore propose that CKS1 primarily functions within the SAM to establish boundaries between meristematic and leaf zones. Loss of gene function disrupts boundary formation, impacts phyllotactic patterns, and leads to aspects of indeterminate growth within leaf primordia. Because these perturbations arise independently of ectopic KNOX activity, the cks1 mutation defines a novel component of the developmental machinery that facilitates leaf-versus-shoot development in maize.
Regulation ofWUSCHELTranscription in the Stem Cell Niche of the Arabidopsis Shoot Meristem
Authors: Bäurle Isabel , Laux Thomas
Published: June 2005

Pluripotent stem cells are localized in specialized microenvironments, called stem cell niches, where signals from surrounding cells maintain their undifferentiated status. In the Arabidopsis thaliana shoot meristem, the homeobox gene WUSCHEL (WUS) is expressed in the organizing center underneath the stem cells and integrates regulatory information from several pathways to define the boundaries of the stem cell niche. To investigate how these boundaries are precisely maintained within the proliferating cellular context of the shoot meristem, we analyzed the transcriptional control of the WUS gene. Our results show that the WUS promoter contains distinct regulatory regions that control tissue specificity and levels of transcription in a combinatorial manner. However, a 57-bp regulatory region is all that is required to control the boundaries of WUS transcription in the shoot meristem stem cell niche, and this activity can be further assigned to two adjacent short sequence motifs within this region. Our results indicate that the diverse regulatory pathways that control the stem cells in the shoot meristem converge at these two short sequence elements of the WUS promoter, suggesting that the integration of regulatory signals takes place at the level of a central transactivating complex.
Seven Lotus japonicus Genes Required for Transcriptional Reprogramming of the Root during Fungal and Bacterial Symbiosis
Authors: Kistner Catherine , Winzer Thilo , Pitzschke Andrea , Mulder Lonneke , Sato Shusei , Kaneko Takakazu , Tabata Satoshi , Sandal Niels , Stougaard Jens , Webb K. Judith , Szczyglowski Krzysztof , Parniske Martin
Published: June 2005

A combined genetic and transcriptome analysis was performed to study the molecular basis of the arbuscular mycorrhiza (AM) symbiosis. By testing the AM phenotype of nodulation-impaired mutants and complementation analysis, we defined seven Lotus japonicus common symbiosis genes (SYMRK, CASTOR, POLLUX, SYM3, SYM6, SYM15, and SYM24) that are required for both fungal and bacterial entry into root epidermal or cortical cells. To describe the phenotype of these mutants at the molecular level, we screened for differentiating transcriptional responses of mutant and wild-type roots by large-scale gene expression profiling using cDNA-amplified fragment length polymorphism. Two percent of root transcripts was found to increase in abundance during AM development, from which a set of AM-regulated marker genes was established. A Ser-protease (SbtS) and a Cys-protease (CysS) were also activated during root nodule development. AM-induced transcriptional activation was abolished in roots carrying mutations in common symbiosis genes, suggesting a central position of these genes in a pathway leading to the transcriptional activation of downstream genes. By contrast, AM fungus-induced gene repression appeared to be unaffected in mutant backgrounds, which indicates the presence of additional independent signaling pathways.
The crystal structure of TrxA(CACA): Insights into the formation of a [2Fe‐2S] iron–sulfur cluster in an Escherichia coli thioredoxin mutant
Authors: Collet Jean‐Francois , Peisach Daniel , Bardwell James C.A. , Xu Zhaohui
Published: June 2005

Escherichia coli thioredoxin is a small monomeric protein that reduces disulfide bonds in cytoplasmic proteins. Two cysteine residues present in a conserved CGPC motif are essential for this activity. Recently, we identified mutations of this motif that changed thioredoxin into a homodimer bridged by a [2Fe‐2S] iron–sulfur cluster. When exported to the periplasm, these thioredoxin mutants could restore disulfide bond formation in strains lacking the entire periplasmic oxidative pathway. Essential for the assembly of the iron–sulfur was an additional cysteine that replaced the proline at position three of the CGPC motif. We solved the crystalline structure at 2.3 Å for one of these variants, TrxA(CACA). The mutant protein crystallized as a dimer in which the iron–sulfur cluster is replaced by two intermolecular disulfide bonds. The catalytic site, which forms the dimer interface, crystallized in two different conformations. In one of them, the replacement of the CGPC motif by CACA has a dramatic effect on the structure and causes the unraveling of an extended α‐helix. In both conformations, the second cysteine residue of the CACA motif is surface‐exposed, which contrasts with wildtype thioredoxin where the second cysteine of the CXXC motif is buried. This exposure of a pair of vicinal cysteine residues apparently allows thioredoxin to acquire an iron–sulfur cofactor at its active site, and thus a new activity and mechanism of action.
Validation of the Australian/English version of the Diabetes Management Self‐Efficacy Scale
Authors: McDowell Jan , Courtney Mary , Edwards Helen , Shortridge‐Baggett Lillie
Published: June 2005

Australians’ use of the English language is influenced by a British educational curriculum, exposure to international television programmes and cultural backgrounds. Hence, adapting research instruments for use with Australian populations can be challenging. This study adapted the United Kingdom's version of the 20‐item Diabetes Management Self‐Efficacy Scale and tested it psychometrically with Australians. Face validity of the adapted instrument was established through consultation with diabetes educators and people with type 2 diabetes. Data from a convenience sample of 88 people with type 2 diabetes were analysed to determine the psychometric properties of the adapted instrument. The results indicate that the Australian/English version of the instrument is internally consistent, stable over time and it measures self‐efficacy. However, there was evidence to show that there might be some redundant items in the scale. Further psychometric testing is warranted with a larger sample to determine whether the scale requires refinement.
Poikiloderma of Civatte: a clinical and epidemiological study
Authors: Katoulis AC , Stavrianeas NG , Georgala S , Bozi E , Kalogeromitros D , Koumantaki E , Katsambas AD
Published: June 2005

Background  Although a common dermatosis, idiopathic poikiloderma of the face and neck has not been studied in depth for decades.

Objectives  To reassess the clinical and epidemiological characteristics of poikiloderma of Civatte (PC).

Material and Methods  Fifty consecutive patients with PC. Evaluation included history taking and physical examination. Epidemiological and clinical parameters were recorded and analysed. The literature from 1923 until today, was reviewed thoroughly.

Results  The frequency of PC among dermatologic patients was estimated to be 1.4%. There were 34 females (68%) and 16 males in the present study. The mean age at diagnosis was 47.8 years for females and 61.7 years for males. The majority (88%) had skin phototype II or III. Among females, 26 were at their peri‐menopausal stage, including three cases of iatrogenic menopause. Four patients reported that other blood‐related family members also had PC. The v and the sides of the neck and the upper chest were most often affected in a symmetric distribution. The face (preauricular and parotid region) was involved in 19 patients (38%). The erythemato‐telangiectatic clinical type predominated (58%), followed by the mixed (22%) and the pigmented type (20%). Almost half of the patients (46%) were symptomatic (itching, burning and ‘flushing’). The mean duration from onset to diagnosis was 6.2 years according to the patients’ report. The course was usually slowly progressive (82%) and irreversible.

Conclusions  PC shows characteristic features, supporting the theory that it represents a distinct entity. It is rather common in Greece. Although menopausal women predominated in our cohort, men were not uncommonly affected and were diagnosed at an older age. Based on the predominating clinical feature, PC can be classified into three clinical forms. Symmetry and sparing of the anatomically shaded areas of the neck are highly characteristic for PC. Face involvement was not as common and as severe as it had been considered in the past. Recognition of clinical type is important for the selection of the most appropriate treatment, which, despite the advent of novel modalities, remains problematic.
Who speaks “broken English”? US undergraduates’ perceptions of non‐native English1
Authors: Lindemann Stephanie
Published: June 2005

This study attempts to discover how native US English speakers construct social categories for people outside the US. A close look at one group's belief system provides insights that can be used in addressing linguistic discrimination, with information on how varieties and features of varieties are perceived. Here 79 US undergraduates labeled maps with descriptions of English spoken by international students, and 208 rated the English of students from 58 countries. Familiarity and socio‐political relationships with countries of origin appeared to play a role in responses. Evaluation was often central to description, with a category of stigmatized, often “broken”, English used for all non‐native speakers except perhaps (Western) Europeans. Salient subgroups were: negatively evaluated “Chinese” English, somewhat negatively evaluated “Mexican” English, and “harsh” and “guttural” Russian English. Respondents had competing frameworks for classifying Indian and German English. A model of these overlapping categories and implications for addressing linguistic prejudice are suggested.
The Role of Diet in Migraine
Authors: Medina Jose L. , Diamond Seymour
Published: June 2005

SYNOPSIS

Twenty‐four migraineurs were placed on three diets: A, B, and C for 18 weeks. Diet A foods contained tyramine, exclusive of tyramine‐free foodstuff. Diet B patients consumed tyramine‐freefoods and excluded those containing tyramine. The Diet C group ate and drank ad‐lib. The results showed no significant difference in the severity of migraine in any diet; however, some headaches were time‐locked to the ingestion of alcohol, chocolate and fasting. These dietary factors probably do not increase the frequency of headaches but may precipitate them earlier. In general, diet appears to be relatively unimportant in migraine.
Impact of Migraine in the United States: Data from the National Health Interview Survey
Authors: Stang Paul E. , Osterhaus Jane T.
Published: June 2005

SYNOPSIS

Data from the 1989 National Health Interview Survey concerning migraine occurrence and impairment were analyzed to assess the impact of migraine on the US population. About four of every one hundred persons in the United States were found to have migraine, accounting for nearly 10 million individuals. Migraine was most prevalent in those aged 25 to 44 years and was about 2.5 times more frequent in females than males. Migraine was most common in whites (85%) and those with low household income. In women, migraine prevalence increased with the level of education. About 10% of migrainous children missed at least one day of school over a two‐week period due to migraine; nearly 1% missed four days. Migraineurs were bedridden for about three million days per month and had an estimated 74.2 million days per year of restricted activity due to migraine. The potential cost of lost productivity was estimated at $1.4 billion per year for the estimated 6,196,378 migraineurs who worked outside the home. It is difficult to derive similar estimates for costs of lost productivity in housewives; however, housewives experienced an estimated 38 million days per year of restricted activity. Eighty‐five percent of females and 77% of males reported a physician visit at some point for their migraine. Migraine is a relatively common disease whose social and financial impact has been poorly understood.
A Placebo‐Controlled Crossover Trial Using Trazodone in Pediatric Migraine
Authors: Battistella P.A. , Ruffilli R. , Cernetti R. , Pettenazzo A. , Baldin L. , Bertoli S. , Zacchello F.
Published: June 2005

SYNOPSIS

An 8‐month, double‐blind, placebo‐controlled cross‐over trial was carried out on the use of trazodone in pediatric migraine prophylaxis. It involved 40 patients aged 7 to 18 years old and suffering from migraine without aura, randomly divided into 2 groups.

After a 4‐week run‐in period, Group A received oral trazodone (1 mg/kg a day divided into 3 doses) for 12 weeks, while Group B received a placebo. After a further 4‐week washout period, Group A was given the placebo and Group B was treated with trazodone for a further 12 weeks. The trial was completed by 35 patients, the number of drop‐outs being comparable in the two groups.

During the first treatment period, both the frequency and the duration of the migraine episodes were significantly reduced in both groups. During the second, a significant further improvement in both parameters was only observed in Group B. No side‐effects were observed at any time. Our results showed that, like other antidepressants, trazodone is a valid prophylactic agent for juvenile migraine.
Comprehensive Inpatient Treatment for Intractable Migraine: A Prospective Long‐Term Outcome Study
Authors: Lake Alvin E. , Saper Joel R. , Madden Scott F. , Kreeger Christopher
Published: June 2005

SYNOPSIS

This paper describes outcome data for 100 patients with severe, intractable, persistent migraine (chronic daily headache), who were admitted to a comprehensive inpatient Head‐Pain Treatment Unit for a mean of 8.5 days. Headache, pain‐related behavior, depression, sleep disturbance, functional performance, work status, and medication use were assessed at admission, post‐discharge (mean=2.3 weeks) and long‐term follow‐up (mean=8.3 months).

Significant improvement noted two weeks after discharge was maintained over time. Long‐term results revealed a 64% reduction in the mean number of days in a 2‐week period with severe to incapacitating headache (6.29 to 2.26), with a corresponding increase in pain‐free days (1.03 to 5.40). At follow‐up, the frequency of severe headaches was reduced by at least 50% for 75% of the patients. The mean rating of overall improvement was 74%. Patients on work‐leave due to pain dropped from 24% to 4%, while the number of working patients rose from 31% to 53%. The data showed statistically significant reductions in days lost to pain, depression, sleep disturbance, and use of symptomatic medication. All the above analyses were significant at P=.000. These results demonstrate the efficacy of the inpatient headache program intervention for this group of patients.
Reduced Sensitivity of Lymphocyte Beta‐Adrenergic Receptors in Migraine
Authors: Kuritzky A. , Bennet E. , Hering R. , Ebstein R.
Published: June 2005

SYNOPSIS

Cyclic AMP(CAMP) accumulation induced by isoproterenol (IP) and forskolin in intact lymphocytes was determined in 12 patients with migraine and 12 healthy controls. Our data showed that IP CAMP accumulation (8.20 + 1.08 Pmol/million cells) was significantly (P = 0.033) lower than accumulation in the controls (14.39 + 2.44 Pmol/million cells). Forskolin‐induced CAMP did not differ in the two groups. These findings support the association of migraine and a reduced lymphocyte beta‐adrenergic receptor sensitivity. An alteration in lymphocyte beta‐adrenergic receptor may reflect similar changes in central beta‐adrenergic function and may be used as a probe to evaluate its activity.
Cerebral Aneurysm Presenting as Cough Headache
Authors: Smith Wade S. , Messing Robert O.
Published: June 2005

SYNOPSIS

The diagnosis of benign cough headache syndrome currently requires non‐invasive brain imaging to exclude structural and mass lesions. We describe a patient with a cerebral aneurysm who presented with recurrent cough headache as her initial symptom. Conventional cerebral angiography was required for the diagnosis. Cerebral aneurysm should be considered in the differential diagnosis of cough headache syndrome.
GABAA Receptors as Broadcasters of Sexually Differentiating Signals in the Brain
Authors: Galanopoulou Aristea S.
Published: June 2005

Summary:  Epileptic seizures are more common in males than in females. One of the areas that has recently been implicated in the higher susceptibility of males to seizures is the substantia nigra reticulata (SNR). Several studies support the existence of phenotypic differences between male and female infantile SNR neurons, and particularly in several aspects of the GABAergic system, including its ability to control seizures. We have recently found that at postnatal day 14–17 (PN14–17) rats, which are equivalent to infants, activation of GABAA receptors has different physiological effects in male and female SNR neurons. This is likely due to the differences in the expression of the neuronal‐specific potassium‐chloride co‐transporter KCC2, which regulates the intracellular chloride concentration. In male PN14–17 SNR neurons, GABAA‐receptor activation with muscimol causes depolarization and increments in intracellular calcium concentration and the expression of calcium regulated genes, such as KCC2. Blockade of L‐type voltage‐sensitive calcium channels (L‐VSCC) by nifedipine decreases KCC2 mRNA expression. However, in PN14–17 females, muscimol hyperpolarizes the SNR neurons, does not increase intracellular calcium, and decreases KCC2 mRNA expression. In PN15 females, nifedipine has no effect on KCC2 mRNA expression in the SNR. This sexually dimorphic function of GABAA receptors also creates divergent patterns of estradiol signaling. In male PN15 rats, estradiol decreases KCC2 mRNA expression in SNR neurons. Pretreatment with the GABAA‐receptor antagonist bicuculline or with nifedipine, prevents the appearance of estradiol‐mediated downregulation of KCC2 mRNA expression. In contrast, in PN15 females, estradiol does not influence KCC2 expression. These findings show that, in infantile rats, drugs or conditions that modulate the activity of GABAA receptors or L‐VSCCs have different effects on the differentiation of the SNR. As a result, they have the potency of causing long‐term changes in the function of the SNR in the control of seizures, movement, and the susceptibility to and course of epilepsy and movement disorders.
Analysis of Seizure Onset on the Basis of Wideband EEG Recordings
Authors: Bragin Anatol , Wilson Charles L. , Fields Tony , Fried Itzhak , Engel Jerome
Published: June 2005

Summary:  Seventy‐five seizure onsets recorded with depth electrodes in the frequency band from 0.1 to 70 Hz were analyzed in 19 patients with intractable temporal lobe epilepsy. It was shown that 89% of low‐voltage fast‐type seizures contained an initial slow wave, whereas hypersynchronous‐type seizures did not show an initial slow wave. Voltage depth profile analysis illustrated that the peak amplitude of the initial slow‐wave onset was in white matter, whereas the peak amplitude of hypersynchronous onset was in deep temporal areas (hippocampus, entorhinal cortex, or amygdala). The difference in voltage depth profiles suggests that these two types of seizure onsets have different mechanisms of generation. The absence of phase reversal of the initial slow wave in white matter or at the border of deep temporal areas indicates a possible nonneuronal mechanism of generation.
Growth‐associated Protein 43 Expression in Hippocampal Molecular Layer of Chronic Epileptic Rats Treated with Cycloheximide
Authors: Longo Beatriz , Vezzani Annamaria , Mello Luiz Eugênio
Published: June 2005

Summary:  Purpose: GAP43 has been thought to be linked with mossy fiber sprouting (MFS) in various experimental models of epilepsy. To investigate how GAP43 expression (GAP43‐ir) correlates with MFS, we assessed the intensity (densitometry) and extension (width) of GAP43‐ir in the inner molecular layer of the dentate gyrus (IML) of rats subject to status epilepticus induced by pilocarpine (Pilo), previously injected or not with cycloheximide (CHX), which has been shown to inhibit MFS.

Methods: CHX was injected before the Pilo injection in adult Wistar rats. The Pilo group was injected with the same drugs, except for CHX. Animals were killed between 30 and 60 days later, and brain sections were processed for GAP43 immunohistochemistry.

Results: Densitometry showed no significant difference regarding GAP43‐ir in the IML between Pilo, CHX+Pilo, and control groups. However, the results of the width of the GAP43‐ir band in the IML showed that CHX+Pilo and control animals had a significantly larger band (p = 0.03) as compared with that in the Pilo group.

Conclusions: Our current finding that animals in the CHX+Pilo group have a GAP43‐ir band in the IML, similar to that of controls, reinforces prior data on the blockade of MFS in these animals. The change in GAP43‐ir present in Pilo‐treated animals was a thinning of the band to a very narrow layer just above the granule cell layer that is likely to be associated with the loss of hilar cell projections that express GAP‐43.
Functional Properties of ES Cell–Derived Neurons Engrafted into the Hippocampus of Adult Normal and Chronically Epileptic Rats
Authors: Rüschenschmidt Christiane , Koch Peter G. , Brüstle Oliver , Beck Heinz
Published: June 2005

Summary: Purpose:Embryonic stem (ES) cell–based therapy strategies are thought to bear considerable promise in chronic neurologic disorders. Nonetheless, studies addressing the functional properties of ES cell–derived progeny after transplantation into the adult, pathologically modified CNS are scarce.

Methods:We therefore transplanted ES cell–derived neural precursors expressing enhanced green fluorescent protein only in neuronal progeny bilaterally into the hippocampi of pilocarpine‐treated chronically epileptic and sham‐control rats. Whole‐cell patch‐clamp recordings of identified ES cell–derived neurons (ESNs) in hippocampal slices were performed 13 to 34 days after transplantation.

Results:Most ESNs were found in clusters at the transplant site and did not migrate into host tissue. However, they gave rise to a dense network of processes extending over large distances into the host tissue. All ESNs possessed the ability to generate action potentials and expressed voltage‐gated Na+and K+currents, as well as hyperpolarization‐activated currents. Likewise, most ESNs received non–N‐methyl‐d‐aspartate (NMDA) and γ‐aminobutyric acid (GABA)Areceptor‐mediated synaptic input. Both types of synapses displayed intact short‐term plasticity. An unusual feature of the majority of ESNs was the occurrence of spontaneous pacemaking activity at frequencies ∼3 Hertz. No obvious differences were found between the functional properties of ESNs in sham‐control and in pilocarpine‐treated rats.

Conclusions:After transplantation into adult control and epileptic rats, ESNs displayed intrinsic and synaptic properties characteristic of neurons. Even though ESNs remained close to the transplant site, the formation of extensive networks of graft‐derived processes may be useful for ES cell–based substance delivery.
In‐house validation of the BACTEC 9240 blood culture system for detection of bacterial contamination in platelet concentrates
Authors: Dunne Wm. Michael , Case Linda K. , Isgriggs Liz , Lublin Douglas M.
Published: June 2005

BACKGROUND: At present, only two commercially available automated culture systems are cleared by the FDA for the purpose of quality control (QC) testing for bacterial contamination of platelet (PLT) concentrates: the BacT/ALERT blood culture system (bioMérieux) and the Pall eBDS (Pall Corporation), both of which allow testing of leukoreduced apheresis as well as whole blood–derived PLTs. After the decision of the AABB to institute universal QC testing of PLT concentrates for evidence of bacterial contamination, in‐house validation of the performance of our current blood culture system, the BACTEC 9240, was carried out for this purpose.

STUDY DESIGN AND METHODS: Serial dilutions of nine species of bacteria commonly associated with PLT contamination were prepared in one single‐donor apheresis PLT unit per organism. Four mL of dilutions containing less than 1 to greater than 103 colony‐forming units (CFUs) per mL was inoculated into blood culture bottles (Standard 10 Aerobic/F, Becton‐Dickinson Diagnostic Systems) and incubated in a BACTEC 9240 continuously monitored blood culture system. Positive bottles were removed from the system and subcultured to insure the identity of bacterial growth.

RESULTS: With the exception of Streptococcus mitis, the BACTEC system provided a detection sensitivity of less than 10 CFUs per mL for Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, Bacillus cereus, Enterobacter cloacae, and Pseudomonas aeruginosa. The limit of detection for the S. mitis test strain was 61 CFUs per mL. Detection of positive bottles ranged from 6.5 to 17.6 hours depending on the species tested and the cell density of the inoculum. Ongoing use of this system for bacterial detection yielded two true‐positive samples from 3879 apheresis PLT products collected at our hospital‐based donor center over 9 months.

CONCLUSION: This study validates the use of the BACTEC 9240 continuously monitored blood culture system for the detection of low‐level bacterial contamination in single donor apheresis PLTs in less than 24 hours.