bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of Transverse Relaxation Optimized Spectroscopy (TROSY) on NMR as a technique in structural biology
Authors: Pervushin Konstantin 
Published: July 2002

1. Transverse relaxation and the molecular size limit in liquid state NMR 1612. TROSY: how does it work? 1632.1 Transverse relaxation in coupled spin systems 1632.2 The TROSY effect, relaxation due to remote protons and 2H isotope labeling 1653. Direct heteronuclear chemical shift correlations 1683.1 Single-Quantum [15N,1H]-TROSY 1683.2 Zero-Quantum [15N,1H]-TROSY 1713.3 Single-Quantum TROSY with aromatic 13C–1H moieties 1764. Resonance assignment and NOE spectroscopy of large biomolecules 1804.1 TROSY-based triple resonance experiments for 13C, 15N and 1HN backbone resonance assignment in uniformly 2H, 13C, 15N labeled proteins 1804.2 TROSY-type NOE spectroscopy 1865. Scalar coupling across hydrogen bonds observed by TROSY 1876. The use of TROSY for measurements of residual dipolar coupling constants 1907. Conclusions 1918. Acknowledgements 1919. References 191The application of nuclear magnetic resonance (NMR) spectroscopy for structure
determination of proteins and nucleic acids (Wüthrich, 1986) with molecular mass exceeding
30 kDa is largely constrained by two factors, fast transverse relaxation of spins of interest and
complexity of NMR spectra, both of which increase with increasing molecular size (Wagner,
1993b; Clore & Gronenborn, 1997, 1998b; Kay & Gardner, 1997). The good news is that
neither of these factors represent a fundamental limit for the application of NMR techniques
to protein structure determination in solution (Clore & Gronenborn, 1998a; Wüthrich, 1998;
Wider & Wüthrich, 1999). In fact, in the past few years the size limitations imposed by these
factors have been pushed up to 50–70 kDa by the use of 13C, 15N and 2H isotope labeling
combined with selective reprotonation of individual chemical groups in conjunction with the
use of triple-resonance experiments (Bax, 1994; Gardner et al. 1997; Gardner & Kay, 1998)
and heteronuclear-resolved NMR (Fesik & Zuiderweg, 1988; Marion et al. 1989a; Otting &
Wüthrich, 1990). Among the largest biomolecules whose 3D structure was solved by NMR
are the 44 kDa trimeric ectodomain of simian immunodeficiency virus (SIV) gp41 (Caffrey et
al. 1998) and 40–60 kDa particles of the elongation initiation factor 4E solubilized in CHAPS
micelles (Matsuo et al. 1997; McGuire et al. 1998).
Neuronal basis of dreaming and mentation during slow-wave (non-REM) sleep
Authors: Steriade M. 
Published: July 2002

Although the cerebral cortex is deprived of messages from the external world in REM sleep and because these messages are inhibited in the thalamus, cortical neurons display high rates of spontaneous firing and preserve their synaptic excitability to internally generated signals during this sleep stage. The rich activity of neocortical neurons during NREM sleep consists of prolonged spike-trains that impose rhythmic excitation onto connected cells in the network, eventually leading to a progressive increase in their synaptic responsiveness, as in plasticity processes. Thus, NREM sleep may be implicated in the consolidation of memory traces acquired during wakefulness.[Hobson et al.; Nielsen; Vertes & Eastman]
Novel mating behaviour in Florelliceps stutchburyae gen. nov., sp. nov. (Onychophora: Peripatopsidae) from Australia
Authors: Tait Noel N. , Norman Jennifer M. 
Published: July 2002

AbstractWhile mating behaviour in onychophorans has been documented in only a few species, it would appear that male reproductive strategies include both dermal and vaginal insemination. To add to this diversity, the males of many newly described species of Australian onychophorans display elaborate head structures. In some species, these head structures have been shown to carry spermatophores. Here we describe Florelliceps stutchburyae gen. nov., sp. nov., a species possessing a unique head structure. An account of its unusual mating behaviour is provided in which the male's everted head structure was placed against the female's gonopore and held there by the claws of the female's reduced last pair of oncopods. After the individuals separated, the female's genital opening was covered by a spermatophore and histological sections showed that sperm had been released into her reproductive tract. A review of mating behaviour in onychophorans is also included with a discussion of sperm acquisition by the female and its correlation with her reproductive cycle.
Introduction to the Special Issue-Trade and environment: local versus multilateral reforms
Authors: BARRETT SCOTT 
Published: July 2002

[We] must ensure that ordinary citizens in all countries actually benefit from tradeÑa trade that...protects the environment.President William J. ClintonState of the Union Address, 19 January 1999The hullabaloo that was the World Trade Organization's millenium
meeting in Seattle has shown us that ordinary people have serious misgivings
about the multilateral trading regime-both the rules and the process.
Future progress in trade liberalization will depend on convincing the
wider public that trade agreements are good for the environment and
good for development (including labour and human rights), not just GDP.
This is more than a public relations challenge. The concerns voiced by the
Seattle protesters-some of them, anyway-raise profound intellectual
questions.
Computational and Experimental Analysis of Microsatellites in Rice (Oryza sativa L.): Frequency, Length Variation, Transposon Associations, and Genetic Marker Potential
Authors: Temnykh Svetlana , DeClerck Genevieve , Lukashova Angelika , Lipovich Leonard , Cartinhour Samuel , McCouch Susan 
Published: July 2002

A total of 57.8 Mb of publicly available rice (Oryza sativaL.) DNA sequence was searched to determine the frequency and distribution of different simple sequence repeats (SSRs) in the genome. SSR loci were categorized into two groups based on the length of the repeat motif. Class I, or hypervariable markers, consisted of SSRs ≥20 bp, and Class II, or potentially variable markers, consisted of SSRs ≥12 bp <20 bp. The occurrence of Class I SSRs in end-sequences of EcoRI- and HindIII-digested BAC clones was one SSR per 40 Kb, whereas in continuous genomic sequence (represented by 27 fully sequenced BAC and PAC clones), the frequency was one SSR every 16 kb. Class II SSRs were estimated to occur every 3.7 kb in BAC ends and every 1.9 kb in fully sequenced BAC and PAC clones. GC-rich trinucleotide repeats (TNRs) were most abundant in protein-coding portions of ESTs and in fully sequenced BACs and PACs, whereas AT-rich TNRs showed no such preference, and di- and tetranucleotide repeats were most frequently found in noncoding, intergenic regions of the rice genome. Microsatellites with poly(AT)n repeats represented the most abundant and polymorphic class of SSRs but were frequently associated with the Micropon family of miniature inverted-repeat transposable elements (MITEs) and were difficult to amplify. A set of 200 Class I SSR markers was developed and integrated into the existing microsatellite map of rice, providing immediate links between the genetic, physical, and sequence-based maps. This contribution brings the number of microsatellite markers that have been rigorously evaluated for amplification, map position, and allelic diversity in Oryza spp. to a total of 500.[Clone sequences for 199 markers (RM1–RM88, RM200–RM345) developed in this lab are available as GenBank accessions AF343840–AF343869 andAF344003–AF344169.]
Delayed Abscission and Shorter Internodes Correlate with a Reduction in the Ethylene Receptor LeETR1 Transcript in Transgenic Tomato
Authors: Whitelaw Catherine A. , Lyssenko Nicholas N. , Chen Liwei , Zhou Dingbo , Mattoo Autar K. , Tucker Mark L. 
Published: July 2002

Abstract
Stable transformation of tomato (Lycopersicon esculentum cv Ailsa Craig) plants with a construct containing the antisense sequence for the receiver domain and 3′-untranslated portion of the tomato ethylene receptor (LeETR1) under the control of an enhanced cauliflower mosaic virus 35S promoter resulted in some expected and unexpected phenotypes. In addition to reduced LeETR1 transcript levels, the two most consistently observed phenotypes in the transgenic lines were delayed abscission and reduced plant size. Fruit coloration and softening were essentially unaffected, and all the seedlings from first generation seed displayed a normal triple response to ethylene. Two independent lines with a single copy of the transgene and reducedLeETR1 transcript accumulation were selected for detailed phenotypic analysis of second generation (R1) plants. Delayed abscission, shorter internode length, and reduced auxin movement all correlated with the presence of the transgene and the degree of reducedLeETR1 transcript accumulation. No significant differences were noted for fruit coloration or fruit softening on R1 plants and all seedlings from R1 and R2 seed displayed a normal triple response. LeETR2 transcript accumulation was only slightly reduced in the R1 plants compared with azygous plants, andLeETR3 (NR) transcript levels appeared to be unaffected by the transgene. We propose that ethylene signal transduction occurs through parallel paths that partially intersect to regulate shared ethylene responses.
Ethylene Enhances Water Transport in Hypoxic Aspen
Authors: Kamaluddin Mohammed , Zwiazek Janusz J. 
Published: July 2002

AbstractWater transport was examined in solution culture grown seedlings of aspen (Populus tremuloides) after short-term exposures of roots to exogenous ethylene. Ethylene significantly increased stomatal conductance, root hydraulic conductivity (L p), and root oxygen uptake in hypoxic seedlings. Aerated roots that were exposed to ethylene also showed enhanced L p. An ethylene action inhibitor, silver thiosulphate, significantly reversed the enhancement of L p by ethylene. A short-term exposure of excised roots to ethylene significantly enhanced the root water flow (Q v), measured by pressurizing the roots at 0.3 MPa. The Q v values in ethylene-treated roots declined significantly when 50 μm HgCl2was added to the root medium and this decline was reversed by the addition of 20 mm 2-mercaptoethanol. The results suggest that the response of Q v to ethylene involves mercury-sensitive water channels and that root-absorbed ethylene enhanced water permeation through roots, resulting in an increase in root water transport and stomatal opening in hypoxic seedlings.
Temperature Acclimation of Photosynthesis and Related Changes in Photosystem II Electron Transport in Winter Wheat
Authors: Yamasaki Takenobu , Yamakawa Tomokazu , Yamane Yoshihiro , Koike Hiroyuki , Satoh Kazuhiko , Katoh Sakae 
Published: July 2002

AbstractWinter wheat (Triticum aestivum L. cv Norin No. 61) was grown at 25°C until the third leaves reached about 10 cm in length and then at 15°C, 25°C, or 35°C until full development of the third leaves (about 1 week at 25°C, but 2–3 weeks at 15°C or 35°C). In the leaves developed at 15°C, 25°C, and 35°C, the optimum temperature for CO2-saturated photosynthesis was 15°C to 20°C, 25°C to 30°C, and 35°C, respectively. The photosystem II (PS II) electron transport, determined either polarographically with isolated thylakoids or by measuring the modulated chlorophyll a fluorescence in leaves, also showed the maximum rate near the temperature at which the leaves had developed. Maximum rates of CO2-saturated photosynthesis and PS II electron transport determined at respective optimum temperatures were the highest in the leaves developed at 25°C and lowest in the leaves developed at 35°C. So were the levels of chlorophyll, photosystem I and PS II, whereas the level of Rubisco decreased with increasing temperature at which the leaves had developed. Kinetic analyses of chlorophyll afluorescence changes and P700 reduction showed that the temperature dependence of electron transport at the plastoquinone and water-oxidation sites was modulated by the temperature at which the leaves had developed. These results indicate that the major factor that contributes to thermal acclimation of photosynthesis in winter wheat is the plastic response of PS II electron transport to environmental temperature.
Molecular Cloning of a Metallothionein-Like Gene from Nicotiana glutinosa L. and Its Induction by Wounding and Tobacco Mosaic Virus Infection
Authors: Choi D. , Kim H. M. , Yun H. K. , Park J. A. , Kim W. T. , Bok S. H. 
Published: July 2002

Abstract
The cloning and characterization of genes expressed in plant disease resistance could be an initial step toward understanding the molecular mechanisms of disease resistance. A metallothionein-like gene that is inducible by tobacco mosaic virus and by wounding was cloned in the process of subtractive cloning of disease resistance-response genes in Nicotiana glutinosa. One 530-bp cDNA clone (KC9–10) containing an open reading frame of 81 amino acids was characterized. Genomic Southern blot hybridization with the cDNA probe revealed that tobacco metallothionein-like genes are present in few or in one copy per diploid genome. Northern blot hybridization detected strong induction of a 0.5-kb mRNA by wounding and tobacco mosaic virus infection, but only mild induction was detected when copper was tested as an inducer. Methyl jasmonate, salicylic acid, and ethylene were also tested as possible inducers of this gene, but they had no effect on its expression. The possible role of this gene in wounded and pathogen-stressed plants is discussed.
Tissue-Specific Activity of Two Manganese Superoxide Dismutase Promoters in Transgenic Tobacco
Authors: Van Camp W. , Herouart D. , Willekens H. , Takahashi H. , Saito K. , Van Montagu M. , Inze D. 
Published: July 2002

Abstract
In eukaryotes, manganese superoxide dismutase is a nuclear-encoded protein that scavenges superoxide radicals in the mitochondrial matrix. We have isolated two manganese superoxide dismutase genes from Nicotiana plumbaginifolia L. and fused the 5[prime] upstream regulatory region of these genes to the β-glucuronidase reporter gene. The two gene fusions displayed a differential tissue specificity in transgenic tobacco (Nicotiana tabacum). Promoter activity of the SodA1 gene fusion was found in the pollen, middle layer, and stomium of anthers, but was usually undetectable in vegetative organs of mature plants. The SodA2 gene fusion was expressed in the leaves, stems, roots, and flowers. SodA2 promoter activity was most prominent in the vascular bundles, stomata, axillary buds, pericycle, stomium, and pollen. Histochemical analysis of succinate dehydrogenase activity suggested that the spatial expression of the two gene fusions is generally correlated with mitochondrial respiratory activity.
Structure-Function Relationship of Monocot Mannose-Binding Lectins
Authors: Barre A. , Van Damme EJM. , Peumans W. J. , Rouge P. 
Published: July 2002

Abstract
The monocot mannose-binding lectins are an extended superfamily of structurally and evolutionarily related proteins, which until now have been isolated from species of the Amaryllidaceae, Alliaceae, Araceae, Orchidaceae, and Liliaceae. To explain the obvious differences in biological activities, the structure-function relationships of the monocot mannose-binding lectins were studied by a combination of glycan-binding studies and molecular modeling using the deduced amino acid sequences of the currently known lectins. Molecular modeling indicated that the number of active mannose-binding sites per monomer varies between three and zero. Since the number of binding sites is fairly well correlated with the binding activity measured by surface plasmon resonance, and is also in good agreement with the results of previous studies of the biological activities of the mannose-binding lectins, molecular modeling is of great value for predicting which lectins are best suited for a particular application.
The Major Intrinsic Protein Family of Arabidopsis Has 23 Members That Form Three Distinct Groups with Functional Aquaporins in Each Group
Authors: Weig A. , Deswarte C. , Chrispeels M. J. 
Published: July 2002

Abstract
Aquaporins, proteins that enhance the permeability of biological membranes to water, are widely distributed in living organisms. They are 26- to 29-kD proteins that belong to the major intrinsic protein (MIP) family of channels. By searching the Arabidopsis thaliana expressed sequence tag database and by using the polymerase chain reaction with oligonucleotides to conserved plant aquaporin domains, we identified 23 expressed Arabidopsis MIP genes. Eight of these had been previously identified as active aquaporins, and two additional ones are now reported to have water-transport activity in Xenopus laevis oocytes. One of these is highly expressed in suspension-cultured cells. On a dendrogram these 23 MIP sequences cluster into three groups: the first group has 11 members and contains the plasma membrane aquaporins, the second group also has 11 members and contains the tonoplast aquaporins, and the third group has only a single member. This MIP protein, provisionally called At-NLM1, is most closely related to the Gm-NOD26 protein that is found in the bacteroid membranes of soybean (Glycine max L.) nodules; At-NLM1 is an active aquaporin when expressed in oocytes. With a semiquantitative slot-blot analysis technique, we determined the expression levels of 22 MIP genes in the various organs. The quantitative polymerase chain reaction was used to determine the effects of various stress treatments on the expression of NLM1.
Mechanosensitive Expression of a Lipoxygenase Gene in Wheat
Authors: Mauch F. , Kmecl A. , Schaffrath U. , Volrath S. , Gorlach J. , Ward E. , Ryals J. , Dudler R. 
Published: July 2002

Abstract
Touch stimulation of wheat (Triticum aestivum L.) seedlings led to a strong and dose-dependent increase in the level of lipoxygenase mRNA transcripts. The touch-induced response occurred within 1 h and was transient. A similar response was observed after wind treatment and wounding. The mechanical strain-regulated lipoxygenase might translate mechanical strain into lipoxygenase pathway-dependent growth responses.
Three 1-Aminocyclopropane-1-Carboxylate Synthase Genes Regulated by Primary and Secondary Pollination Signals in Orchid Flowers1
Authors: Bui Anhthu Q. , Neill Sharman D. O' 
Published: July 2002

Abstract
The temporal and spatial expression patterns of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes were investigated in pollinated orchid (Phalaenopsis spp.) flowers. Pollination signals initiate a cascade of development events in multiple floral organs, including the induction of ethylene biosynthesis, which coordinates several postpollination developmental responses. The initiation and propagation of ethylene biosynthesis is regulated by the coordinated expression of three distinct ACC synthase genes in orchid flowers. One ACC synthase gene (Phal-ACS1) is regulated by ethylene and participates in amplification and interorgan transmission of the pollination signal, as we have previously described in a related orchid genus. Two additional ACC synthase genes (Phal-ACS2 andPhal-ACS3) are expressed primarily in the stigma and ovary of pollinated orchid flowers. Phal-ACS2 mRNA accumulated in the stigma within 1 h after pollination, whereasPhal-ACS1 mRNA was not detected until 6 h after pollination. Similar to the expression of Phal-ACS2, thePhal-ACS3 gene was expressed within 2 h after pollination in the ovary. Exogenous application of auxin, but not ACC, mimicked pollination by stimulating a rapid increase in ACC synthase activity in the stigma and ovary and inducing Phal-ACS2and Phal-ACS3 mRNA accumulation in the stigma and ovary, respectively. These results provide the basis for an expanded model of interorgan regulation of three ACC synthase genes that respond to both primary (Phal-ACS2 and Phal-ACS3) and secondary (Phal-ACS1) pollination signals.
Characterization of Recombinant Rhamnogalacturonan α-l-Rhamnopyranosyl-(1,4)-α-d-Galactopyranosyluronide Lyase from Aspergillus aculeatus1
Authors: Mutter Margien , Colquhoun Ian J. , Beldman Gerrit , Schols Henk A. , Bakx Edwin J. , Voragen Alphons G.J. 
Published: July 2002

Abstract
The four major oligomeric reaction products from saponified modified hairy regions (MHR-S) from apple, produced by recombinant rhamnogalacturonan (RG) α-l-rhamnopyranosyl-(1,4)-α-d-galactopyranosyluronide lyase (rRG-lyase) from Aspergillus aculeatus, were isolated and characterized by 1H-nuclear magnetic resonance spectroscopy. They contain an alternating RG backbone with a degree of polymerization of 4, 6, 8, and 10 and with an α-Δ-(4,5)-unsaturated d-galactopyranosyluronic acid at the nonreducing end and an l-rhamnopyranose at the reducing end. l-Rhamnopyranose units are substituted at C-4 with β-galactose. The maximum reaction rate of rRG-lyase toward MHR-S at pH 6.0 and 31°C was 28 units mg−1. rRG-lyase and RG-hydrolase cleave the same alternating RG I subunit in MHR. Both of these enzymes fragment MHR by a multiple attack mechanism. The catalytic efficiency of rRG-lyase for MHR increases with decreasing degree of acetylation. Removal of arabinose side chains improves the action of rRG-lyase toward MHR-S. In contrast, removal of galactose side chains decreased the catalytic efficiency of rRG-lyase. Native RG-lyase was purified from A. aculeatus, characterized, and found to be similar to the rRG-lyase expressed inAspergillus oryzae.
Family of MADS-Box Genes Expressed Early in Male and Female Reproductive Structures of Monterey Pine
Authors: Mouradov Aidyn , Glassick Tina V. , Hamdorf Britt A. , Murphy Lawrence C. , Marla Soma S. , Yang Yumin , Teasdale Robert D. 
Published: July 2002

Abstract
Three MADS-box genes isolated from Monterey pine (Pinus radiata), PrMADS1, PrMADS2, and PrMADS3, are orthologs to members of the AGL2 and AGL6 gene subfamilies in Arabidopsis. These genes were expressed during early stages of pine shoot development in differentiating seed- and pollen-cone buds. Their transcripts were found within a group of cells that formed ovuliferous scale and microsporophyll primordia. Expression ofPrMADS3 was also detected in a group of cells giving rise to needle primordia within differentiated vegetative buds, and in needle primordia.
(+)-Germacrene A Biosynthesis
Authors: de Kraker Jan-Willem , Franssen Maurice C.R. , de Groot Aede , König Wilfried A. , Bouwmeester Harro J. 
Published: July 2002

Abstract
The leaves and especially the roots of chicory (Cichorium intybus L.) contain high concentrations of bitter sesquiterpene lactones such as the guianolides lactupicrin, lactucin, and 8-deoxylactucin. Eudesmanolides and germacranolides are present in smaller amounts. Their postulated biosynthesis through the mevalonate-farnesyl diphosphate-germacradiene pathway has now been confirmed by the isolation of a (+)-germacrene A synthase from chicory roots. This sesquiterpene cyclase was purified 200-fold using a combination of anion-exchange and dye-ligand chromatography. It has a Km value of 6.6 μm, an estimated molecular mass of 54 kD, and a (broad) pH optimum around 6.7. Germacrene A, the enzymatic product, proved to be much more stable than reported in literature. Its heat-induced Cope rearrangement into (−)-β-elemene was utilized to determine its absolute configuration on an enantioselective gas chromatography column. To our knowledge, until now in sesquiterpene biosynthesis, germacrene A has only been reported as an (postulated) enzyme-bound intermediate, which, instead of being released, is subjected to additional cyclization(s) by the same enzyme that generated it from farnesyl diphosphate. However, in chicory germacrene A is released from the sesquiterpene cyclase. Apparently, subsequent oxidations and/or glucosylation of the germacrane skeleton, together with a germacrene cyclase, determine whether guaiane- or eudesmane-type sesquiterpene lactones are produced.