bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Orbital Period of Nova V2540 Ophiuchi (2002)
Authors: Ak Tansel , Retter Alon , Liu Alex 
Published: December 2005

AbstractWe present the results of 26 nights of CCD photometry of the nova V2540 Oph (2002) from 2003 to 2004. We find a period of 0.284781 ± 0.000006 d (6.8347 ± 0.0001 h) in the data. Since this period was present in the light curves taken in both years, with no apparent change in its value or amplitude, we interpret it as the orbital period of the nova binary system. The mass–period relation for cataclysmic variables yields a secondary mass of about 0.75 ± 0.04 M⊙. From maximum magnitude–rate of decline relation, we estimate a maximum absolute visual magnitude ofMV= −6.2 ± 0.4 mag. This value leads to an uncorrected distance modulus of (m–M) = 14.7 ± 0.7. By using the interstellar reddening for the location of V2540 Oph, we find a rough estimate for the distance of 5.2 ± 0.8 kpc. We propose that V2540 Oph is either (1) a high-inclination cataclysmic variable showing a reflection effect of the secondary star, or having a spiral structure in the accretion disc, (2) a high-inclination intermediate polar system, or less likely (3) a polar.
Galaxy Groups: Proceedings from a Swinburne University Workshop
Authors: Kilborn Virginia A. , Bekki Kenji , Brough Sarah , Doyle Marianne T. , Evstigneeva Ekaterina A. , Forbes Duncan A. , Koribalski Bärbel S. , Owers Matthew S. , Power Chris , Drinkwater Michael J. , Rohde David J. , Blake Christopher A. , Couch Warrick J. , Pracy Michael B. , Gibson Brad K. 
Published: December 2005

AbstractWe present the proceedings from a two-day workshop held at Swinburne University on 2005 May 24–25. The workshop participants highlighted current Australian research on both theoretical and observational aspects of galaxy groups. These proceedings include short one-page summaries of a number of the talks presented at the workshop. The talks presented ranged from reconciling N-body simulations with observations, to the Hı content of galaxies in groups and the existence of ‘dark galaxies’. The formation and existence of ultra-compact dwarfs in groups, and a new supergroup in Eridanus were also discussed.
Explaining Sub‐Saharan Africa's Manufacturing Performance
Authors: Lawrence Peter 
Published: December 2005

AbstractThis article surveys Africa's industrial, and especially manufacturing performance over the last four decades and reviews explanations for that performance which relate to issues of structure and class; structural adjustment policies; exports, technology, finance, and transactions costs. The article considers the extent to which manufacturing success is related to increasing exports and concludes with some consideration of future policy in the wake of the recently published report by the Commission for Africa. A strong role for the state is considered to be essential for successful growth in the future, both as substitute for a non‐existent domestic capitalist class, and as planner and director of manufacturing industrialization.
Bacitracin reveals a role for multiple thiol isomerases in platelet function
Authors: Robinson Aisling , O'Neill Sarah , Kiernan Aoife , O'Donoghue Niaobh , Moran Niamh 
Published: December 2005

SummaryThe platelet‐specific integrin αIIbβ3 has endogenous thiol isomerase activity associated with the CXXC motifs within the β subunit. Using a highly purified form of bacitracin, a thiol isomerase inhibitor, we now provide further evidence of the functional significance of this enzymatic activity in integrin activation. In addition, we demonstrate a role for multiple thiol isomerases in platelet function. This bacitracin prevented platelet aggregation to thrombin and collagen, and directly inhibited αIIbβ3 activation, as detected by PAC‐1 binding. In parallel, bacitracin inhibited the endogenous thiol isomerase activity of purified αIIbβ3 with a 50% inhibitory concentration of 15·5 μmol/l. In order to determine whether the effects of bacitracin are solely mediated by inhibition of integrin enzymatic activity, we examined integrin‐independent indices of platelet activation. We found bacitracin inhibited both platelet secretion (CD62P and CD63) and thromboxane (TxA2) production, with complete inhibition at different concentrations. Thus, we demonstrated a role for multiple thiol isomerases in platelet function. Taken together, these studies support a role for the endogenous integrin thiol isomerase activity in activation of αIIbβ3 and highlight the novel regulation of platelet function by other, as yet undefined thiol isomerases.
Role of prospective screening of blood for invasive aspergillosis by polymerase chain reaction in febrile neutropenic recipients of haematopoietic stem cell transplants and patients with acute leukaemia
Authors: Halliday Catriona , Hoile Rebecca , Sorrell Tania , James Greg , Yadav Satya , Shaw Peter , Bleakley Marie , Bradstock Ken , Chen Sharon 
Published: December 2005

SummaryGuidelines for the use of polymerase chain reaction (PCR)‐based assays to aid the diagnosis of invasive aspergillosis (IA) in high‐risk haematology patients have not been formulated. We prospectively evaluated a nested PCR assay to detect Aspergillus in blood during 95 febrile neutropenic episodes, in patients with haematological malignancy and haematopoietic stem cell transplant (HSCT) recipients. PCR results were correlated with the diagnostic classification of the 2002 European Organisation for Research and Treatment of Cancer/Mycosis Study Group. When two‐positive results were used to define an episode as ‘PCR positive’, the sensitivity, specificity, positive‐predictive value and negative predictive value for ‘proven’/‘probable’ IA (n = 13) were 100%, 75·4%, 46·4% and 100%, respectively. Consecutive positive results occurred in 61·5% of these 13 episodes. Overall, PCR positivity preceded standard diagnosis by a mean of 14 d and the median time between positive results was shorter than that in other categories of IA. All 13 episodes occurred in the setting of allogeneic HSCT recipients and acute leukaemia. If ‘eligibility’ for antifungal therapy were based on two‐positive‐PCR tests, use of empiric treatment could have been reduced by up to 37%. The nested PCR assay is a practical screening test for excluding IA. Patients with consecutive positive results or intermittent‐positive results (within 14 d) warrant immediate investigations for IA and the initiation of antifungal therapy.
Differential immune effects mediated by Toll‐like receptors stimulation in precursor B‐cell acute lymphoblastic leukaemia
Authors: Corthals Sophie L. , Wynne Kristin , She Kevin , Shimizu Hiromi , Curman Darko , Garbutt Kristy , Reid Gregor S. D. 
Published: December 2005

AbstractAcute lymphoblastic leukaemia (ALL) is the most common paediatric malignancy and, although current therapy is widely effective, relapse remains a significant clinical problem for which new treatment strategies are required. The ligation of Toll‐like receptors (TLR) on antigen‐presenting cells stimulates the generation of strong T‐cell helper type 1 (Th1) adaptive immune responses. Although TLR9 ligation has been shown to enhance immunogenicity of a number of leukaemia cell types, there have been few reports of the effects mediated through other TLR. In this study we analysed both the expression of TLR by B‐cell precursor ALL cell lines and the effects of individual TLR ligation on the ability of ALL cells to stimulate allogeneic T cells. While ligation of TLR2, TLR 7 and TLR9 led to detectable changes in ALL costimulatory molecule expression, only TLR2 and TLR9 stimulation influenced T‐cell responses. The TLR2 ligand Pam3CysSerLys4 provoked the most significant changes in T‐cell response, dramatically augmenting interferon‐γ production. These results suggest that TLR ligands, in addition to TLR9 agonists, may provide a strategy to enhance the generation of anti‐ALL immune activity by skewing responding T cells towards a Th1 response.
The stress‐gradient hypothesis does not fit all relationships between plant–plant interactions and abiotic stress: further insights from arid environments
Authors: MAESTRE FERNANDO T. , VALLADARES FERNANDO , REYNOLDS JAMES F. 
Published: December 2005

Summary

Our earlier meta‐analysis of the effects of abiotic stress on the outcome of plant–plant interactions, suggested that the magnitude of the net effect provided by neighbours, whether positive or negative, was not higher under high abiotic stress conditions. This result, which does not support predictions of the stress‐gradient hypothesis, has been questioned on the basis of limitations in our analytical approach, on the inappropriateness of some of the studies included in our data bases, and on the criteria used to select the levels of abiotic stress within each study. Here we provide additional arguments in defence of our approach and selection of studies, and perform further analyses of our data base that show that these criticisms are not well founded.
The inclusion of studies with contrasting abiotic stress conditions does not invalidate per se tests of predictions derived from the stress‐gradient hypothesis because the hypothesis does not specify that predictions should hold for a given difference, or range of differences, in abiotic stress.
Our re‐analyses show that differences in the length of stress gradient between the low and high stress levels across studies do not reduce the ability of meta‐analysis to test predictions of the stress‐gradient hypothesis, and that our approach does not suffer from ‘hypothesis bias’.
Species interactions across abiotic stress gradients do not follow a simple pattern, and there are specific circumstances under which the predictions arising from the stress‐gradient hypothesis do not hold. This hypothesis requires profound revision if all situations that emerge when evaluating the relationship between plant interactions and abiotic stress are to be ‘fit’ by a single conceptual paradigm.
Long‐term stability and effective population size in North Sea and Baltic Sea cod (Gadus morhua)
Authors: POULSEN NINA Aa. , NIELSEN EINAR E. , SCHIERUP MIKKEL H. , LOESCHCKE VOLKER , GRØNKJÆR PETER 
Published: December 2005

AbstractDNA from archived otoliths was used to explore the temporal stability of the genetic composition of two cod populations, the Moray Firth (North Sea) sampled in 1965 and 2002, and the Bornholm Basin (Baltic Sea) sampled in 1928 and 1997. We found no significant changes in the allele frequencies for the Moray Firth population, while subtle but significant genetic changes over time were detected for the Bornholm Basin population. Estimates of the effective population size (Ne) generally exceeded 500 for both populations when employing a number of varieties of the temporal genetic method. However, confidence intervals were very wide and Ne's most likely range in the thousands. There was no apparent loss of genetic variability and no evidence of a genetic bottleneck for either of the populations. Calculations of the expected levels of genetic variability under different scenarios of Ne showed that the number of alleles commonly reported at microsatellite loci in Atlantic cod is best explained by Ne's exceeding thousand. Recent fishery‐induced bottlenecks can, however, not be ruled out as an explanation for the apparent discrepancy between high levels of variability and recently reported estimates of Ne << 1000. From life history traits and estimates of survival rates in the wild, we evaluate the compatibility of the species’ biology and extremely low Ne/N ratios. Our data suggest that very small Ne's are not likely to be of general concern for cod populations and, accordingly, most populations do not face any severe threat of losing evolutionary potential due to genetic drift.
The C‐terminal end of LpxC is required for degradation by the FtsH protease
Authors: Führer Frank , Langklotz Sina , Narberhaus Franz 
Published: December 2005

SummaryLipopolysaccharide (LPS) biosynthesis is essential in Gram negative bacteria. LpxC, the key enzyme in LPS formation, catalyses the limiting reaction and controls the ratio between LPS and phospholipids. As overproduction of LPS is toxic, the cellular amount of LpxC must be regulated carefully. The membrane‐bound protease FtsH controls the level of LpxC via proteolysis making FtsH the only essential protease of Escherichia coli. We found that the chaperones DnaK and DnaJ co‐purified with LpxC. However, degradation of LpxC was DnaK/J‐independent in contrast to turnover of the heat shock sigma factor σ32 (RpoH). The stability of LpxC in a bacterial one‐hybrid system suggested that a terminus of LpxC might be important for degradation. Different LpxC truncations and extensions were constructed. Removal of at least five amino acids from the C‐terminus abolished degradation by FtsH in vivo. While addition of two aspartic acids to LpxC did not alter its half‐life, the exchange of the last two residues against aspartic acids resulted in stabilization. All stable LpxC enzymes were active in vivo as assayed by their high toxicity. Our data demonstrate that the C‐terminus of LpxC contains a signal sequence necessary for FtsH‐dependent degradation.
A mannan binding lectin is involved in cell–cell attachment in a toxic strain of Microcystis aeruginosa
Authors: Kehr Jan‐Christoph , Zilliges Yvonne , Springer Andreas , Disney Matthew D. , Ratner Daniel D. , Bouchier Christiane , Seeberger Peter H. , De Marsac Nicole Tandeau , Dittmann Elke 
Published: December 2005

SummaryMicrocystin, a hepatotoxin that represents a serious health risk for humans and livestock, is produced by the bloom‐forming cyanobacterium Microcystis aeruginosa in freshwater bodies worldwide. Here we describe the discovery of a lectin, microvirin (MVN), in M. aeruginosa PCC7806 that shares 33% identity with the potent anti‐HIV protein cyanovirin‐N from Nostoc ellipsosporum. Carbohydrate microarrays were employed to demonstrate the high specificity of the protein for high‐mannose structures containing α(1→2) linked mannose residues. Lectin binding analyses and phenotypic characterizations of MVN‐deficient mutants suggest that MVN is involved in cell–cell recognition and cell–cell attachment of Microcystis. A binding partner of MVN was identified in the lipopolysaccharide fraction of M. aeruginosa PCC7806. MVN is differentially expressed in mutants lacking the hepatotoxin microcystin. Additionally, MVN‐deficient mutants contain much lower amounts of microcystin than the wild‐type cells. We discuss a possible functional correlation between microcystin and the lectin and possible implications on Microcystis morphotype formation. This study provides the first experimental evidence that microcystins may have an impact on Microcystis colony formation that is highly important for the competitive advantage of Microcystis over other phytoplankton species.
Sucrose transporter LeSUT1 and LeSUT2 inhibition affects tomato fruit development in different ways
Authors: Hackel Aleksandra , Schauer Nicolas , Carrari Fernando , Fernie Alisdair R. , Grimm Bernhard , Kühn Christina 
Published: December 2005

SummarySucrose transporters of higher plants belong to a large gene family. At least four different sucrose transporters are known in Solanaceous plants, although their function remains to be elucidated in detail. The isolation of LeSUT1 and LeSUT2from Lycopersicon esculentum has been described earlier. Whereas SUT1 is supposed to be the main phloem loader of sucrose in Solanaceae, the role of SUT2 remains a matter of debate. A transgenic approach was taken to evaluate the potential functions of SUT2/SUC3 proteins in sucrose transport or sensing. Expression of LeSUT1 and LeSUT2 was inhibited independently in transgenic tomato plants, using the antisense technique, in order to analyse their specific functions. Although the phloem‐specific inhibition of LeSUT1 antisense plants showed a phenotype consistent with an essential role in phloem loading, constitutive LeSUT2 antisense inhibition exclusively affected tomato fruit and seed development. Neither LeSUT1, nor the LeSUT2 antisense plants were able to produce normal tomato fruits; however, it is likely that independent mechanisms underlie these phenomena. While phloem loading was blocked in LeSUT1 antisense plants, the fertility of fruits was reduced in LeSUT2 antisense plants. A detailed physiological analysis of these plants established a role for SUT2 in pollen tube growth and thus assigned a physiological role for SUT2.
Downregulation of Solanum americanum genes encoding proteinase inhibitor II causes defective seed development
Authors: Sin Suk‐Fong , Yeung Edward C. , Chye Mee‐Len 
Published: December 2005

SummaryProteinase inhibitor II proteins (PIN2) are serine proteinase inhibitors found in the Solanaceae. Here, we assign functions in seed development to two Solanum americanum genes, SaPIN2a and SaPIN2b, encoding proteinase inhibitor II. Their mRNAs and proteins have been previously localized to the reproductive tissues, including the inner cell layers of ovules in senescent flowers at the beginning of fruit development, suggestive of their endogenous roles in reproductive development. We have employed RNA interference (RNAi)‐induced post‐transcriptional gene silencing (PTGS) to further investigate the role of SaPIN2a and SaPIN2b during seed development. A SaPIN2a‐derived construct that shared 83% nucleotide homology to SaPIN2b was used in PTGS to silence both genes. Northern blot analyses confirmed that the PIN2–RNAi transgenic plants contain small interfering RNAs (siRNAs) and exhibit reduced levels of SaPIN2a and SaPIN2b mRNAs at various stages of floral development. A reduction in seed set due to seed abortion was observed in PIN2‐RNAi transgenic lines. Cytological and molecular analyses of these lines showed the lack of SaPIN2a and SaPIN2b mRNAs and proteins at the inner cell layers of the ovules in senescent flowers. Aborted seeds in transgenic fruits had an abnormal endothelium. The anomalous expansion of the endothelium prevented proper development of the endosperm and embryo, leading to seed abortion. Our observations indicate that SaPIN2a and SaPIN2b are essential for seed development and suggest that the endothelium may protect the embryo sac, allowing proper formation of the endosperm and embryo, as a result of its ability to produce proteinase inhibitors.
The Arabidopsis heavy metal P‐type ATPase HMA5 interacts with metallochaperones and functions in copper detoxification of roots
Authors: Andrés‐Colás Nuria , Sancenón Vicente , Rodríguez‐Navarro Susana , Mayo Sonia , Thiele Dennis J. , Ecker Joseph R. , Puig Sergi , Peñarrubia Lola 
Published: December 2005

SummarySince copper (Cu) is essential in key physiological oxidation reactions, organisms have developed strategies for handling Cu while avoiding its potentially toxic effects. Among the tools that have evolved to cope with Cu is a network of Cu homeostasis factors such as Cu‐transporting P‐type ATPases that play a key role in transmembrane Cu transport. In this work we present the functional characterization of an Arabidopsis Cu‐transporting P‐type ATPase, denoted heavy metal ATPase 5 (HMA5), and its interaction with Arabidopsis metallochaperones. HMA5 is primarily expressed in roots, and is strongly and specifically induced by Cu in whole plants. We have identified and characterized plants carrying two independent T‐DNA insertion alleles, hma5‐1 and hma5‐2. Both mutants are hypersensitive to Cu but not to other metals such as iron, zinc or cadmium. Interestingly, root tips from Cu‐treated hma5 mutants exhibit a wave‐like phenotype at early stages and later on main root growth completely arrests whereas lateral roots emerge near the crown. Accordingly, these lines accumulate Cu in roots to a greater extent than wild‐type plants under Cu excess. Finally, yeast two‐hybrid experiments demonstrate that the metal‐binding domains of HMA5 interact with Arabidopsis ATX1‐like Cu chaperones, and suggest a regulatory role for the plant‐specific domain of the CCH Cu chaperone. Based on these findings, we propose a role for HMA5 in Cu compartmentalization and detoxification.
Analysis of the root‐hair morphogenesis transcriptome reveals the molecular identity of six genes with roles in root‐hair development in Arabidopsis
Authors: Jones Mark A. , Raymond Marjorie J. , Smirnoff Nicholas 
Published: December 2005

SummaryRoot‐hair morphogenesis is a model for studying the genetic regulation of plant cell development, and double‐mutant analyses have revealed a complex genetic network underlying the development of this type of cell. Therefore, to increase knowledge of gene expression in root hairs and to identify new genes involved in root‐hair morphogenesis, the transcriptomes of the root‐hair differentiation zone of wild‐type (WT) plants and a tip‐growth defective root‐hair mutant, rhd2‐1, were compared using Affymetrix ATH1 GeneChips®. A set of 606 genes with significantly greater expression in WT plants defines the ‘root‐hair morphogenesis transcriptome’. Compared with the whole genome, this set is highly enriched in genes known to be involved in root‐hair morphogenesis. The additional gene families and functional groups enriched in the root‐hair morphogenesis transcriptome are cell wall enzymes, hydroxyproline‐rich glycoproteins (extensins) and arabinogalactan proteins, peroxidases, receptor‐like kinases and proteins with predicted glycosylphosphatidylinositol (GPI) anchors. To discover new root‐hair genes, 159 T‐DNA insertion lines identified from the root‐hair morphogenesis transcriptome were screened for defects in root‐hair morphogenesis. This identified knockout mutations in six genes (RHM1–RHM6) that affected root‐hair morphogenesis and that had not previously been identified at the molecular level: At2g03720 (similar to Escherichia coli universal stress protein); At3g54870 (armadillo‐repeat containing kinesin‐related protein); At4g18640 (leucine‐rich repeat receptor‐like kinase subfamily VI); At4g26690 (glycerophosphoryl diester phosphodiesterase‐like GPI‐anchored protein); At5g49270 (COBL9 GPI‐anchored protein) and At5g65090 (inositol‐1,4,5 triphosphate 5‐phosphatase‐like protein). The mutants were transcript null, their root‐hair phenotypes were characterized and complementation testing with uncloned root‐hair genes was performed. The results suggest a role for GPI‐anchored proteins and lipid rafts in root‐hair tip growth because two of these genes (At4g26690 and At5g49270) encode predicted GPI‐anchored proteins likely to be associated with lipid rafts, and several other genes previously shown to be required for root‐hair development also encode proteins associated with sterol‐rich lipid rafts.