bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical evolution of Nova Ophiuchi 2007 = V2615 Oph
Authors: Munari U. , Henden A. , Valentini M. , Siviero A. , Dallaporta S. , Ochner P. , Tomasoni S. 
Published: May 2008

Abstract
The moderately fast Nova Oph 2007 reached maximum brightness on 2007 March 28 at V= 8.52, B−V=+1.12, V−RC=+0.76, V−IC=+1.59 and RC−IC=+0.83, after fast initial rise and a pre-maximum halt lasting a week. Decline times were tV2= 26.5, tB2= 30, tV3= 48.5 and tB3= 56.5 d. The distance to the nova is d= 3.7 ± 0.2 kpc, the height above the Galactic plane is z= 215 pc, the reddening is E(B−V) = 0.90 and the absolute magnitude at maximum is MmaxV=−7.2 and MmaxB=−7.0. The spectrum four days before maximum resembled a F6 supergiant, in an agreement with broad-band colours. It later developed into that of a standard ‘Fe ii’-class nova. Nine days past maximum, the expansion velocity estimated from the width of Hα emission component was ∼730 km s−1, and the displacement from it of the principal and diffuse-enhanced absorption systems was ∼650 and 1380 km s−1, respectively. Dust probably formed and disappeared during the period from 82 to 100 d past maximum, causing (at peak dust concentration) an extinction of ΔB= 1.8 mag and an extra ΔE(B−V) = 0.44 reddening.
Neutralizing IL‐21 and IL‐15 Inhibits Pro‐inflammatory Cytokine Production in Rheumatoid Arthritis
Authors: Andersson A. K. , Feldmann M. , Brennan F. M. 
Published: May 2008

AbstractInterleukin (IL)‐21 and IL‐15 belong to the common γ‐chain receptor family. IL‐15 represents a novel therapeutic target in rheumatoid arthritis (RA), whereas less is known about the role of IL‐21 in human inflammatory diseases. We have analysed the effects of blocking IL‐21 and IL‐15 on spontaneous production of pro‐inflammatory cytokines in RA synovial cell cultures. RA synovial membrane cells were cultured in the presence of an IL‐21R‐Fc chimera or a neutralizing IL‐15 antibody and production of tumour necrosis factor (TNF)α, IL‐6 and IL‐1β was measured by enzyme‐linked immunosorbent assay (ELISA). Expression of IL‐21 and IL‐15 in RA synovium was measured by RT‐PCR and ELISA. mRNA for IL‐21 and IL‐21R was detected in the culture cell lysates. Protein for IL‐15 was found at detectable levels in the cell lysates. Both the IL‐21R‐Fc chimera and anti‐IL‐15 antibody inhibited cytokine release, although substantially more IL‐21R‐Fc was needed. IL‐21R‐Fc at the highest dose (100 μg/ml) significantly reduced TNFα production by 50%, IL‐6 by 57% and IL‐1β by 81%. Anti‐IL‐15 antibody (5 μg/ml) significantly inhibited TNFα release by 51%, IL‐6 by 37% and IL‐1β by 82% in line with previous published observations. The data confirm that IL‐15 plays a role in RA and suggests that IL‐21 is also involved in driving the pro‐inflammatory cytokine response in RA.
Advances in Type I Diabetes Associated Tolerance Mechanisms
Authors: Chentoufi A. A. , Binder N. R. , Berka N. , Abunadi T. , Polychronakos C. 
Published: May 2008

AbstractType 1 diabetes (T1D) is an autoimmune disease resulting from the destruction of insulin‐producing pancreatic β cells by autoreactive T cells. The polygenic trait for T1D risk implicates many genes that have an impact on fundamental immunological processes such as central and peripheral tolerance. Several pieces of evidence have suggested that many of the genetic loci that are directly linked to type 1 diabetes susceptibility modulate the generation and/or the activation of autoreactive T‐lymphocytes. We and others have proposed a critical role for medullary thymic epithelial cells (mTEC) forming the Hassall’s corpuscles in T‐cell tolerance. Indeed, mTEC have been found to express promiscuous self‐antigens, used directly or through thymic dendritic cells to drive either negative selection of insulin‐reacting precursors or their differentiation into naturally occurring regulatory Foxp3+ CD4+ CD25+ T cells. In the periphery, naturally occurring Foxp3+ CD4+ CD25+ regulatory T (Treg) cells represent the master cells in dominant peripheral T‐cell tolerance. The development and function of Treg cells are ultimately linked to IL‐2 and Foxp3 expression. This review addresses recent literature and emerging concepts of central and peripheral T‐cell tolerance with regards to T1D.
Nature’s assembly line: biosynthesis of simple phenylpropanoids and polyketides
Authors: Yu Oliver , Jez Joseph M. 
Published: May 2008

SummaryPlants produce large amounts of phenylpropanoids, both in terms of molecular diversity and absolute quantity of these compounds. The phenylpropanoids, and the related plant polyketides, have multiple biological functions. They serve to attract pollinators, support secondary cell‐wall growth, provide protection against various plant diseases, and interact with beneficial soil microbes. Their basic chemical properties also make them useful in the biofuel and biomaterial industries. Phenylpropanoid metabolism begins with the amino acid phenylalanine, which feeds into various biosynthetic pathways that generate a wide range of structurally related polyphenolic compounds. This review focuses on four sub‐groups of these polyphenolic compounds – polyketides, stilbenes, isoflavones and catechins. We discuss the biosynthesis of these molecules, their physiological role in plants, and their striking pharmacological and physiological effects on humans. This review also highlights metabolic engineering efforts aimed at increasing or decreasing the amounts of each class of compound in various model plants and crops.
Opium poppy and Madagascar periwinkle: model non‐model systems to investigate alkaloid biosynthesis in plants
Authors: Facchini Peter J. , De Luca Vincenzo 
Published: May 2008

SummaryAlkaloids represent a large and diverse group of compounds that are related by the occurrence of a nitrogen atom within a heterocyclic backbone. Unlike other types of secondary metabolites, the various structural categories of alkaloids are unrelated in terms of biosynthesis and evolution. Although the biology of each group is unique, common patterns have become apparent. Opium poppy (Papaver somniferum), which produces several benzylisoquinoline alkaloids, and Madagascar periwinkle (Catharanthus roseus), which accumulates an array of monoterpenoid indole alkaloids, have emerged as the premier organisms used to study plant alkaloid metabolism. The status of these species as model systems results from decades of research on the chemistry, enzymology and molecular biology responsible for the biosynthesis of valuable pharmaceutical alkaloids. Opium poppy remains the only commercial source for morphine, codeine and semi‐synthetic analgesics, such as oxycodone, derived from thebaine. Catharanthus roseus is the only source for the anti‐cancer drugs vinblastine and vincristine. Impressive collections of cDNAs encoding biosynthetic enzymes and regulatory proteins involved in the formation of benzylisoquinoline and monoterpenoid indole alkaloids are now available, and the rate of gene discovery has accelerated with the application of genomics. Such tools have allowed the establishment of models that describe the complex cell biology of alkaloid metabolism in these important medicinal plants. A suite of biotechnological resources, including genetic transformation protocols, has allowed the application of metabolic engineering to modify the alkaloid content of these and related species. An overview of recent progress on benzylisoquinoline and monoterpenoid indole alkaloid biosynthesis in opium poppy and C. roseus is presented.
Plant triacylglycerols as feedstocks for the production of biofuels
Authors: Durrett Timothy P. , Benning Christoph , Ohlrogge John 
Published: May 2008

SummaryTriacylglycerols produced by plants are one of the most energy‐rich and abundant forms of reduced carbon available from nature. Given their chemical similarities, plant oils represent a logical substitute for conventional diesel, a non‐renewable energy source. However, as plant oils are too viscous for use in modern diesel engines, they are converted to fatty acid esters. The resulting fuel is commonly referred to as biodiesel, and offers many advantages over conventional diesel. Chief among these is that biodiesel is derived from renewable sources. In addition, the production and subsequent consumption of biodiesel results in less greenhouse gas emission compared to conventional diesel. However, the widespread adoption of biodiesel faces a number of challenges. The biggest of these is a limited supply of biodiesel feedstocks. Thus, plant oil production needs to be greatly increased for biodiesel to replace a major proportion of the current and future fuel needs of the world. An increased understanding of how plants synthesize fatty acids and triacylglycerols will ultimately allow the development of novel energy crops. For example, knowledge of the regulation of oil synthesis has suggested ways to produce triacylglycerols in abundant non‐seed tissues. Additionally, biodiesel has poor cold‐temperature performance and low oxidative stability. Improving the fuel characteristics of biodiesel can be achieved by altering the fatty acid composition. In this regard, the generation of transgenic soybean lines with high oleic acid content represents one way in which plant biotechnology has already contributed to the improvement of biodiesel.
Biosynthesis of plant pigments: anthocyanins, betalains and carotenoids
Authors: Tanaka Yoshikazu , Sasaki Nobuhiro , Ohmiya Akemi 
Published: May 2008

SummaryPlant compounds that are perceived by humans to have color are generally referred to as ‘pigments’. Their varied structures and colors have long fascinated chemists and biologists, who have examined their chemical and physical properties, their mode of synthesis, and their physiological and ecological roles. Plant pigments also have a long history of use by humans. The major classes of plant pigments, with the exception of the chlorophylls, are reviewed here. Anthocyanins, a class of flavonoids derived ultimately from phenylalanine, are water‐soluble, synthesized in the cytosol, and localized in vacuoles. They provide a wide range of colors ranging from orange/red to violet/blue. In addition to various modifications to their structures, their specific color also depends on co‐pigments, metal ions and pH. They are widely distributed in the plant kingdom. The lipid‐soluble, yellow‐to‐red carotenoids, a subclass of terpenoids, are also distributed ubiquitously in plants. They are synthesized in chloroplasts and are essential to the integrity of the photosynthetic apparatus. Betalains, also conferring yellow‐to‐red colors, are nitrogen‐containing water‐soluble compounds derived from tyrosine that are found only in a limited number of plant lineages. In contrast to anthocyanins and carotenoids, the biosynthetic pathway of betalains is only partially understood. All three classes of pigments act as visible signals to attract insects, birds and animals for pollination and seed dispersal. They also protect plants from damage caused by UV and visible light.
Prospects for increasing starch and sucrose yields for bioethanol production
Authors: Smith Alison M. 
Published: May 2008

SummaryIn the short term, the production of bioethanol as a liquid transport fuel is almost entirely dependent on starch and sugars from existing food crops. The sustainability of this industry would be enhanced by increases in the yield of starch/sugar per hectare without further inputs into the crops concerned. Efforts to achieve increased yields of starch over the last three decades, in particular via manipulation of the enzyme ADPglucose pyrophosphorylase, have met with limited success. Other approaches have included manipulation of carbon partitioning within storage organs in favour of starch synthesis, and attempts to manipulate source–sink relationships. Some of the most promising results so far have come from manipulations that increase the availability of ATP for starch synthesis. Future options for achieving increased starch contents could include manipulation of starch degradation in organs in which starch turnover is occurring, and introduction of starch synthesis into the cytosol. Sucrose accumulation is much less well understood than starch synthesis, but recent results from research on sugar cane suggest that total sugar content can be greatly increased by conversion of sucrose into a non‐metabolizable isomer. A better understanding of carbohydrate storage and turnover in relation to carbon assimilation and plant growth is required, both for improvement of starch and sugar crops and for attempts to increase biomass production in second‐generation biofuel crops.
Microbial conversion of sugars from plant biomass to lactic acid or ethanol
Authors: Doran‐Peterson Joy , Cook Dana M. , Brandon Sarah K. 
Published: May 2008

SummaryConcerns for our environment and unease with our dependence on foreign oil have renewed interest in converting plant biomass into fuels and ‘green’ chemicals. The volume of plant matter available makes lignocellulose conversion desirable, although no single isolated organism has been shown to depolymerize lignocellulose and efficiently metabolize the resulting sugars into a specific product. This work reviews selected chemicals and fuels that can be produced from microbial fermentation of plant‐derived cell‐wall sugars and directed engineering for improvement of microbial biocatalysts. Lactic acid and ethanol production are highlighted, with a focus on engineered Escherichia coli.
Platform biochemicals for a biorenewable chemical industry
Authors: Nikolau Basil J. , Perera M. Ann D.N. , Brachova Libuse , Shanks Brent 
Published: May 2008

SummaryThe chemical industry is currently reliant on a historically inexpensive, petroleum‐based carbon feedstock that generates a small collection of platform chemicals from which highly efficient chemical conversions lead to the manufacture of a large variety of chemical products. Recently, a number of factors have coalesced to provide the impetus to explore alternative renewable sources of carbon. Here we discuss the potential impact on the chemical industry of shifting from non‐renewable carbon sources to renewable carbon sources. This change to the manufacture of chemicals from biological carbon sources will provide an opportunity for the biological research community to contribute fundamental knowledge concerning carbon metabolism and its regulation. We discuss whether fundamental biological research into metabolic processes at a holistic level, made possible by completed genome sequences and integrated with detailed structural understanding of biocatalysts, can change the chemical industry from being dependent on fossil‐carbon feedstocks to using biorenewable feedstocks. We illustrate this potential by discussing the prospect of building a platform technology based upon a concept of combinatorial biosynthesis, which would explore the enzymological flexibilities of polyketide biosynthesis.
D’orenone blocks polarized tip growth of root hairs by interfering with the PIN2‐mediated auxin transport network in the root apex
Authors: Schlicht Markus , Šamajová Olga , Schachtschabel Doreen , Mancuso Stefano , Menzel Diedrik , Boland Wilhelm , Baluška František 
Published: May 2008

SummaryThe C18 ketone (5E,7E)‐6‐methyl‐8‐(2,6,6‐trimethylcyclohex‐1‐enyl)octa‐5,7‐dien‐2‐one (D’orenone) has been postulated to be an early cleavage product of β‐carotene en route to trisporic acids; these act as morphogenetic factors during the sexual reproduction of zygomycetes. Here we report that D’orenone blocks the highly polarized tip growth of root hairs, causing tip growth to stop completely within a few minutes. Importantly, external auxin reverses the effects of D’orenone on root hairs. Further analysis revealed that D’orenone lowers the auxin concentration in trichoblasts via PIN2‐mediated auxin efflux to below the critical levels essential for root hair growth. D’orenone specifically increases PIN2 protein abundance without affecting PIN2 transcripts, and the PIN2 expression domain enlarges and shifts basipetally, resulting in more active auxin transport. The observation that D’orenone does not interfere with the root hair growth in roots of null mutant lines provides additional evidence that PIN2 is its specific target.
A novel homodimeric geranyl diphosphate synthase from the orchid Phalaenopsis bellina lacking a DD(X)2–4D motif
Authors: Hsiao Yu‐Yun , Jeng Mei‐Fen , Tsai Wen‐Chieh , Chuang Yu‐Chen , Li Chia‐Ying , Wu Tian‐Shung , Kuoh Chang‐Sheng , Chen Wen‐Huei , Chen Hong‐Hwa 
Published: May 2008

SummaryGeranyl diphosphate (GDP) is the precursor of monoterpenes, which are the major floral scent compounds in Phalaenopsis bellina. The cDNA of P. bellina GDP synthase (PbGDPS) was cloned, and its sequence corresponds to the second Asp‐rich motif (SARM), but not to any aspartate‐rich (Asp‐rich) motif. The recombinant PbGDPS enzyme exhibits dual prenyltransferase activity, producing both GDP and farnesyl diphosphate (FDP), and a yeast two‐hybrid assay and gel filtration revealed that PbGDPS was able to form a homodimer. Spatial and temporal expression analyses showed that the expression of PbGDPS was flower specific, and that maximal PbGDPS expression was concomitant with maximal emission of monoterpenes on day 5 post‐anthesis. Homology modelling of PbGDPS indicated that the Glu‐rich motif might provide a binding site for Mg2+ and catalyze the formation of prenyl products in a similar way to SARM. Replacement of the key Glu residues with alanine totally abolished enzyme activity, whereas their mutation to Asp resulted in a mutant with two‐thirds of the activity of the wild‐type protein. Phylogenetic analysis indicated that plant GDPS proteins formed four clades: members of both GDPS‐a and GDPS‐b clades contain Asp‐rich motifs, and function as homodimers. In contrast, proteins in the GDPS‐c and GDPS‐d clades do not contain Asp‐rich motifs, but although members of the GDPS‐c clade function as heterodimers, PbGDPS, which is more closely related to the GDPS‐c clade proteins than to GDPS‐a and GDPS‐b proteins, and is currently the sole member of the GDPS‐d clade, functions as a homodimer.
A role for SENSITIVE TO FREEZING2 in protecting chloroplasts against freeze‐induced damage in Arabidopsis
Authors: Fourrier Nicolas , Bédard Jocelyn , Lopez‐Juez Enrique , Barbrook Adrian , Bowyer John , Jarvis Paul , Warren Gareth , Thorlby Glenn 
Published: May 2008

SummaryThe SENSITIVE TO FREEZING2 (SFR2) gene has an important role in freezing tolerance in Arabidopsis thaliana. We show that homologous genes are present, and expressed, in a wide range of terrestrial plants, including species not able to tolerate freezing. Expression constructs derived from the cDNAs of a number of different plant species, including examples not tolerant to freezing, are able to complement the freezing sensitivity of the Arabidopsis sfr2 mutant. In Arabidopsis the SFR2 protein is localized to the chloroplast outer envelope membrane, as revealed by the analysis of transgenic plants expressing SFR2 fusions to GFP, by confocal microscopy, and by the immunological analysis of isolated chloroplasts treated with thermolysin protease. Moreover, the chloroplasts of the sfr2 mutant show clear evidence of rapid damage after a freezing episode, suggesting a role for SFR2 in the protection of the chloroplast.
A simple and rapid technique for detecting protein phosphorylation using one‐dimensional isoelectric focusing gels and immunoblot analysis
Authors: Anderson Jeffrey C. , Peck Scott C. 
Published: May 2008

SummaryWe report a technique for detecting protein phosphorylation that involves isoelectric focusing in a vertical mini‐gel format followed by immunoblot detection of the target protein. This method uses standard protein gel equipment, allows sensitive detection of protein phosphorylation when phosphospecific antibodies are not available, and provides a stoichiometric measure of phosphorylation. We demonstrate the application of this method for observing phosphorylation of an Arabidopsis thaliana protein in response to biotic stress.
Ethylene signaling in Arabidopsis involves feedback regulation via the elaborate control of EBF2 expression by EIN3
Authors: Konishi Mineko , Yanagisawa Shuichi 
Published: May 2008

SummaryEIN3 is a key transcription factor in the signaling pathway of the plant hormone ethylene in Arabidopsis. Ethylene signaling suppresses the 26S proteasome‐mediated proteolysis of EIN3, the accumulation of which induces ethylene‐responsive gene expression. The proteolysis of EIN3 has been suggested to be mediated by the E3 ubiquitin ligase SCFEBF1/2 that contains either of the two closely related F‐box proteins, EBF1 or EBF2. Here, we demonstrate feedback regulation of ethylene signaling that results from the direct upregulation of the EBF2 gene by EIN3. Although EBF1 and EBF2 show comparable activities as repressors of EIN3‐dependent transcription, our analysis of transgenic Arabidopsis plants has revealed that the EBF2 promoter, but not the EBF1 promoter, is activated by ethylene. Furthermore, the results of protoplast transient assays in vivo and electrophoretic mobility shift assays in vitro have revealed that EIN3 can bind and activate the EBF2 promoter, indicating that EIN3 modulates EBF2 gene expression in planta. An ebf2 mutant transformed with the EBF2 gene under the control of a mutant promoter in which the EIN3‐binding site was disrupted still showed an ethylene hyper‐responsive phenotype, indicating the physiological relevance of EIN3‐mediated activation of the EBF2 gene in the downregulation of ethylene signaling. We show an additional finding that a sequence downstream of the EBF2 coding region is also involved in modulations of both the EBF2 expression level and sensitivity to ethylene. These results thus indicate that the fine‐tuning of ethylene signaling involves the intricate regulation of EBF2 expression in Arabidopsis.
Effect of oregano (O. majorana × O. vulgare) on performance and antioxidative capacity of quails fed a diet rich in ω3 fatty acids
Authors: Handl S. , Hellweg P. , Khol‐Parisini A. , Rossmann B. , Thurner K. , Luf W. , Novak J. , Zentek J. 
Published: May 2008

SummaryOregano possesses high antioxidant activity and could therefore be used to enhance oxidative stability of eggs high in ω3 fatty acids. In this study, 20 female quails were fed a diet containing 4% linseed oil. They were divided into two groups, one receiving oregano, and the other grass meal as control (2% respectively). Cholesterol oxidation products were analysed in fresh eggs, in stored eggs and in the livers. Trolox equivalent antioxidative capacity of plasma was measured. No significant differences were seen between the groups.