bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluvial responses to climate and sea‐level change: a review and look forward
Authors: Blum Michael D. , Törnqvist Torbjörn E. 
Published: March 2003

SummaryFluvial landforms and deposits provide one of the most readily studied Quaternary continental records, and alluvial strata represent an important component in most ancient continental interior and continental margin successions. Moreover, studies of the long‐term dynamics of fluvial systems and their responses to external or ‘allogenic' controls, can play important roles in research concerning both global change and sequence‐stratigraphy, as well as in studies of the dynamic interactions between tectonic activity and surface processes. These themes were energized in the final decades of the twentieth century, and may become increasingly important in the first decades of this millennium.This review paper provides a historical perspective on the development of ideas in the fields of geomorphology/Quaternary geology vs. sedimentary geology, and then summarizes key processes that operate to produce alluvial stratigraphic records over time‐scales of 103−106 years. Of particular interest are changes in discharge regimes, sediment supply and sediment storage en route from source terrains to sedimentary basins, as well as changes in sea‐level and the concept of accommodation. Late Quaternary stratigraphic records from the Loire (France), Mississippi (USA), Colorado (Texas, USA) and Rhine–Meuse (The Netherlands) Rivers are used to illustrate the influences of climate change on continental interior rivers, as well as the influence of interacting climate and sea‐level change on continental margin systems.The paper concludes with a look forward to a bright future for studies of fluvial response to climate and sea‐level change. At present, empirical field‐based research on fluvial response to climate and sea‐level change lags behind: (a) the global change community's understanding of the magnitude and frequency of climate and sea‐level change; (b) the sequence‐stratigraphic community's desire to interpret climate and, especially, sea‐level change as forcing mechanisms; and (c) the modelling community's ability to generate numerical and physical models of surface processes and their stratigraphic results. A major challenge for the future is to catch up, which will require the development of more detailed and sophisticated Quaternary stratigraphic, sedimentological and geochronological frameworks in a variety of continental interior and continental margin settings. There is a particular need for studies that seek to document fluvial responses to allogenic forcing over both shorter (102−103 years) and longer (104−106 years) time‐scales than has commonly been the case to date, as well as in larger river systems, from source to sink. Studies of Quaternary systems in depositional basin settings are especially critical because they can provide realistic analogues for interpretation of the pre‐Quaternary rock record.
Phylogenetic analysis of Myxophaga (Coleoptera) using larval characters
Authors: Beutel R. G.. , Maddison D. R.. , Haas A.. 
Published: March 2003

SummaryA phylogenetic parsimony analysis of fifty‐four larval characters of Myxophaga (excluding Lepiceridae) resulted in two minimal length cladograms. The monophyly of Torridincolidae, Hydroscaphidae and Microsporidae is supported by several autapomorphies: miniaturization, flattened body with laterally extended tergites, broadened head, scale‐like surface structures, broad tentorial bridge, disc‐shaped labral sensilla, spiracular gills and pupation in the last larval exuviae. Hydroscaphidae are the sister group of Microsporidae. Larvae of both families are characterized by semi‐entognathous mouthparts, tergites with posterior rows of lancet‐shaped setae, claws with flattened basal spines and balloon‐shaped spiracular gills. The monophyly of all families is supported by autapomorphies. Torridincolidae excludingDeleveais defined as a monophylum by four derived character states: body ovoid, thorax semicircular and as long as abdomen, labral sensilla fused and abdominal sternite IX distinctly reduced and triangular. The monophyly of Torridincolinae (sensuEndrödy‐Younga 1997b) is supported by two autapomorphies. The proposed branching pattern suggests that the early representatives of Myxophaga (excluding Lepiceridae) were living in aquatic conditions with a preference for hygropetric habitats. The tendency to live on rocks in running water and miniaturization have played an important role in myxophagan evolution.
Cladistic analysis of Neuroptera and their systematic position within Neuropterida (Insecta: Holometabola: Neuropterida: Neuroptera)
Authors: Aspöck Ulrike , Plant John D. , Nemeschkal Hans L. 
Published: March 2003

SummaryA phylogenetic analysis of Neuroptera using thirty‐six predominantly morphological characters of adults and larvae is presented. This is the first computerized cladistic analysis at the ordinal level. It included nineteen species representing seventeen families of Neuroptera, three species representing two families (Sialidae and both subfamilies of Corydalidae) of Megaloptera, two species representing two families of Raphidioptera and as prime outgroup one species of a family of Coleoptera. Ten equally most parsimonious cladograms were found, of which one is selected and presented in detail. The results are discussed in light of recent results from mental phylogenetic cladograms. The suborders Nevrorthi‐ formia, Myrmeleontiformia and Hemerobiiformia received strong support, however Nevrorthiformia formed the adelphotaxon of Myrmeleontiformia + Hemerobiiformia (former sister group of Myrmeleontiformia only). In Myrmeleontiformia, the sister‐group relationships between Psychopsidae + Nemopteridae and Nymphidae + (Myrmeleontidae + Ascalaphidae) are corroborated. In Hemerobiiformia, Ithonidae + Polystoechotidae is confirmed as the sister group of the remaining families. Dilaridae + (Mantispidae + (Rhachiberothidae + Berothidae)), which has already been proposed, is confirmed. Chrysopidae + Osmylidae emerged as the sister group of a clade comprising Hemerobiidae + ((Coniopterygidae + Sisyridae) + (dilarid clade)). Despite the sister‐group relationship of Coniopterygidae + Sisyridae being only weakly supported, the position of Coniopterygidae within the higher Hemerobiiformia is corroborated. At the ordinal level, the analysis provided clear support for the hypothesis that Megaloptera + Neuroptera are sister groups, which upsets the conventional Megaloptera + Raphidioptera hypothesis.
Phylogenetic revision of Agapophytinae subf.n. (Diptera: Therevidae) based on molecular and morphological evidence
Authors: Winterton Shaun L. , Yang Longlong , Wiegmann Brian M. , Yeates David K. 
Published: March 2003

SummaryAgapophytinae subf.n. is a highly diverse lineage of Australasian Therevidae, comprising eight described and two new genera:AgapophytusGuérin‐Méneville,AcupalpaKröber,AcraspisaKröber,BelonalysKröber,BonjeaniaIrwin & Lyneborg,ParapsilocephalaKröber,AcatopygiaKröber,LaxotelaWinterton & Irwin,Pipinniponsgen.n. andPatanothrixgen.n. A genus‐level cladistic analysis of the subfamily was undertaken using sixty‐eight adult morphological characters andc.1000 base pairs of the elongation factor‐1α (EF‐1α) protein coding gene. The morphological data partition produced three most parsimonious cladograms, whereas the molecular data partition gave a single most parsimonious cladogram, which did not match any of the cladograms found in the morphological analysis. The level of congruence between the data partitions was determined using the partition homogeneity test (HTF) and Wilcoxon signed ranks test. Despite being significantly incongruent in at least one of the incongruence tests, the partitions were combined in a simultaneous analysis. The combined data yielded a single cladogram that was better supported than that of the individual partitions analysed separately. The relative contributions of the data partitions to support for individual nodes on the combined cladogram were investigated using Partitioned Bremer Support. The level of support for many nodes on the combined cladogram was non‐additive and often greater than the sum of support for the respective nodes on individual partitions. This synergistic interaction between incongruent data partitions indicates a common phylogenetic signal in both partitions. It also suggests that criteria for partition combination based solely on incongruence may be misleading. The phylogenetic relationships of the genera are discussed using the combined data. A key to genera of Agapophytinae is presented, with genera diagnosed and figured. Two new genera are described:Patanothrixwith a new species (Pat. skevingtoni) andPat. wilsoni(Mann) transferred fromParapsilocephala, andPipinniponswith a new species (Pip. kroeberi).Pipinnipons fascipennis(Kröber) is transferred fromSquamopygiaKröber andPip. imitans(Mann) is transferred fromAgapophytus.Agapophytus bicolor(Kröber) is transferred fromParapsilocephala.Agapophytus varipennisMann is synonymised withAga. queenslandiKröber andAga. flavicornisMann is synonymised withAga. pallidicornis(Kröber).
A repeating 11‐mer amino acid motif and plant desiccation
Authors: Dure Leon 
Published: March 2003

SummaryAmong the proteins that accumulate as plant seeds desiccate are several protein families that are composed principally of a tandemly repeated 11‐mer amino acid motif. Proteins containing the same motif accumulate in the desiccating leaves of a desiccation‐tolerant plant species.This motif is characterized by apolar residues in positions 1, 2, 5 and 9, and charged or amide residues in positions 3, 6, 7, 8 and 11. An α helical arrangement of the 11‐mer repeating unit gives an amphiphilic helix whose hydrophobic stripe twists in a right‐handed fashion around the helix. Should these proteins dimerize via binding of their hydrophobic faces, a right‐handed coiled coil would be formed. Such a structure has not previously been observed. A conceivable function for these proteins in ion sequestration in the desiccated state is proposed.
Mechanosensory calcium‐selective cation channels in epidermal cells
Authors: Ding Jiu Ping , Pickard Barbara G. 
Published: March 2003

SummaryThis paper explores the properties and likely functions of an epidermal Ca2+‐selective cation channel complex activated by tension. As many as eight or nine linked or linkable equivalent conductance units or co‐channels can open together. Open time for co‐channel quadruplets and quintuplets tends to be relatively long with millimolar Mg2+ (but not millimolar Ca2+) at the cytosolic face of excised plasma membrane. Sensitivity to tension is regulated by transmembrane voltage and temperature. Under some circumstances channel activity is synchronized in rhythmic pulses. Certain lanthanides and a cytoskeleton‐disturbing herbicide that inhibit gravitropic reception act on the channel system at low concentrations. Specifically, ethyl‐N‐phenylcarbamate promotes tension‐dependent activity at micromolar levels. With moderate suction, Gd3+ provided at about 0.5 μM at the extracellular face of the membrane promotes for several seconds but may then become inhibitory. Provision at 1–2 μM promotes and subsequently inhibits more vigorously (often abruptly and totally), and at high levels inhibits immediately. La3+, a poor gravitropic inhibitor, acts similarly but much more gradually and only at much higher concentrations. These properties, particularly these susceptibilities to modulation, indicate that in vivo the mechanosensitive channel must be mechano‐sensory and mechanoregulatory. It could serve to transduce the shear forces generated in the integrated wall‐membrane‐cytoskeleton system during turgor changes and cell expansion as well as transducing the stresses induced by gravity, touch and flexure. In so far as such transduction is modulated by voltage and temperature, the channels would also be sensors for these modalities as long as the wall‐membrane‐cytoskeleton system experiences mechanical stress.
A (1→3,1→4)‐β‐glucan‐specific monoclonal antibody and its use in the quantitation and immunocytochemical location of (1→3,1→4)‐β‐glucans
Authors: Meikle Peter J. , Hoogenraad Nicholas J. , Bonig Ingrid , Clarke Adrienne E. , Stone Bruce A. 
Published: March 2003

SummaryMonoclonal antibodies were raised against a (1→3,1→4)‐β‐glucan‐bovine serum albumin (BSA) conjugate. One antibody (BG1) selected for further characterization, was specific for (1→3,1→4)‐β‐glucan, displaying no binding activity against a (1→3)‐β‐glucan‐BSA conjugate and minimal binding against a cellopentaose‐BSA conjugate. A range of oligosaccharides was prepared by enzymatic digestion of (1→3,1→4)‐β‐glucan, purified by size exclusion chromatography and characterized by 1H‐NMR and anion exchange chromatography.These (1→3,1→4)‐β‐oligoglucosides, together with (1→3)‐β‐ and (1→4)‐β‐oligoglucosides were used to characterize the binding site of the monoclonal antibody (BG1) by competitive inhibition. The monoclonal antibody showed maximal binding to a heptasaccharide with the structure Glc(1→3) Glc(1→4) Glc(1→4) Glc(1→3) Glc(1→4) Glc(1→4) Glc and was determined to have an affinity constant of 3.8 × 104 M−1 for this oligoglucoside.The monoclonal antibody (BG1) has been used to develop a sensitive sandwich ELISA for the specific quantitation of (1→3,1→4)‐β‐glucans. The assay operates in the range 1–10 ng ml−1 and shows no significant cross‐reaction with tamarind xyloglucan, wheat endosperm arabinoxylan or carboxymethyl‐pachyman ((1→3)‐β‐glucan). When used with a second‐stage, rabbit anti‐mouse gold conjugate and viewed under the electron microscope, the monoclonal antibody probe was found to bind strongly to the walls of the aleurone in thin sections of immature wheat (Triticum aestivum) cv. Millewa grains but not to the middle lamella region. A previously described specific anti‐(1→3)‐β‐glucan antibody (Meikle et al., 1991) bound to discrete patches on the aleurone walls, believed to be plasmodesmata.
Molecular analysis of protein domain function encoded by the myb‐homologous maize genes C1, Zm 1 and Zm 38
Authors: Franken Philipp , Schrell Susanne , Peterson Peter A. , Saedler Heinz , Wienand Udo 
Published: March 2003

SummaryTwo maize genes, Zm 1 and Zm 38, related to the regulatory anthocyanin gene C1 were analyzed molecularly and used for fusion constructs in transient domain swapping experiments with the C1 wild‐type gene. It was shown that both genes (Zm 1 and Zm 38) influence the expression of the A1 locus, a target gene for C1. Zm 1 activates the A1 promoter, however it does not turn on the whole anthocyanin pathway. The Zm 38 gene product shows functions similar to C1‐I, a dominant inhibitor of the C1 wild‐type gene. Concerning the trans‐inhibition by C1‐I two effects seem to be involved, competition for binding and formation of heterodimers. Further analysis of C1 function was carried out by a fine structure analysis of C1 mutants induced by the insertion and excision of transposable elements. These experiments indicate that for the activating domain of the protein, the formation of an alpha helix seems to be more important than a high negative charge.
Isolation and characterization of two cDNA clones encoding ATP‐sulfurylases from potato by complementation of a yeast mutant
Authors: Klonus Dirk , Höfgen Rainer , Willmitzer Lothar , Riesmeier Jörg W. 
Published: March 2003

SummarySulfur plays an important role in plants, being used for the biosynthesis of amino acids, sulfolipids and secondary metabolites. After uptake sulfate is activated and subsequently reduced to sulfide or serves as donor for sulfurylation reactions. The first step in the activation of sulfate in all cases studied so far is catalyzed by the enzyme ATP‐sulfurylase (E.C. 2.7.7.4.) which catalyzes the formation of adenosine‐5′‐phosphosulfate (APS). Two cDNA clones from potato encoding ATP‐sulfurylases were identified following transformation of a Saccharomyces cerevisiae mutant deficient in ATP‐sulfurylase activity with a cDNA library from potato source leaf poly(A)+ RNA cloned in a yeast expression vector. Several transformants were able to grow on a medium with sulfate as the only sulfur source, this ability being strictly linked to the presence of two classes of cDNAs. The clones StMet3‐1 and StMet3‐2 were further analyzed. DNA analysis revealed an open reading frame encoding a protein with a molecular mass of 48 kDa in the case of StMet3‐1 and 52 kDa for StMet3‐2. The deduced polypeptides are 88% identical at the amino acid level. The clone StMet3‐2 has a 48 amino acid N‐terminal extension which shows common features of a chloroplast transit peptide. Sequence comparison of the ATP‐sulfurylase Met3 from Saccharomyces cerevisiae with the cDNA StMet3‐1 (StMet3‐2) reveals 31% (30%) identity at the amino acid level. Protein extracts from the yeast mutant transformed with the clone StMet3‐1 displayed ATP‐sulfurylase activity. RNA blot analysis demonstrated the expression of both genes in potato leaves, root and stem, but not in tubers. To the best of the authors' knowledge this is the first cloning and identification of genes involved in the reductive sulfate assimilation pathway from higher plants.
Rhizobium meliloti Nod factors elicit cell‐specific transcription of the ENOD12 gene in transgenic alfalfa
Authors: Journet E.P. , Pichon M. , Dedieu A. , De Billy F. , Truchet G. , Barker D.G. 
Published: March 2003

SummaryExtracellular lipo‐oligosaccharides of Rhizobium, known as Nod factors, play a key role in the molecular signal exchange which leads to the specific nitrogen‐fixing symbiotic association between the soil microbe and Its host legume. The biological activity of Nod factors and their perception by the host plant during the earliest stages of the Rhizobium/legume interaction have been studied using transgenic alfalfa carrying a fusion between the promoter of the early nodulin gene MtENOD12 and the β‐glucuronidase (GUS) reporter gene. Histochemical staining has shown that GUS accumulates specifically in the differentiating root epidermis, prior to and during root hair emergence, within 2–3 h following the addition of purified Rhizobium meliloti Nod factors. This precocious transcriptional activation of the MtENOD12 gene, reminiscent of that observed after inoculation with intact Rhizobium, implies that the Nod factor signal can be perceived at a developmental stage preceding root hair formation. GUS activity can be detected following treatment with a wide range of R. meliloti Nod factor concentrations down to 10−13 M, and furthermore, this rapid response to the bacterial elicitor appears to be non‐systemic. Significantly, MtENOD12—GUS expression is not observed after inoculation with a R. meliloti nodH mutant which synthesizes exclusively non‐sulphated Nod factors. Indeed purified Nod factors which lack the sulphate substituent are approximately 1000‐fold less active than their sulphated counterparts. Thus, the triggering of ENOD12 transcription in the alfalfa root epidermis is a rapid molecular response which is subject to the same host‐specificity determinant (Nod factor sulphation) that governs the interaction between alfalfa and its bacterial symbiont.
Chromosomal integration is required for spatial regulation of expression from the β‐phaseolin promoter
Authors: Frisch David A. , Van Der Geest Apolonia H.M. , Dias Kalyani , Hall Timothy C. 
Published: March 2003

SummaryThe stringency of spatial expression of phaseolin, the major storage protein of bean (Phaseolus vulgaris) seeds, has been rigorously evaluated using stable and transient transformation techniques. Transgenic tobacco plants known to be homozygous for the β‐glucuronidase (gus) reporter sequence under the regulation of various lengths of the β‐phaseolin gene (phas) promoter were shown to express gus only in developing seed tissues. No expression was detected in calli initiated from stems, leaves and immature seeds, showing that expression was not leaky in undifferentiated tissues. Control plants and cultures containing gus fused to the CaMV 35S promoter actively expressed gus under identical conditions. It was not possible to induce expression in phas/gus calli with ABA, GA or jasmonic acid. Treatment of the cultures with 5‐azacytidine did not result in expression, excluding methyletlon as the major factor regulating the phas promoter. However, strong gus expression was detected in seed of plants regenerated from these callus cultures, confirming that neither gene rearrangements nor deletion were responsible for the lack of activity seen in tissues other than the developing seed. In contrast to the above observations, strong transient expression of gus was detected in tobacco, bean and soybean leaves following introduction of the phas/gus fusion constructs via biolistic approaches and in electroporated bean leaf and hypocotyl protoplasts. These experiments show unequi‐vocally that the phas promoter is under rigorous spatial control when integrated into the genome, but lacks spatial control when present as extrachromosomal naked DNA. A putative model explaining these differences is presented.
Maternal‐specific demethylation and expression of specific alleles of zein genes in the endosperm of Zea mays L.
Authors: Lund Gertrud , Ciceri Pietro , Viotti Angelo 
Published: March 2003

SummaryZeins constitute 60–70% of maize endosperm protein. Zein genes are specifically transcribed in the endosperm, and a correlation has been established between tissue‐specific expression and demethylation. Three inbred lines and their reciprocal crosses were analysed to assess for allele‐specific differences in methylation, transcription and translation. DNAs from endosperm, embryo and seedling tissues analysed by cleavage with methylation‐sensitive restriction enzymes and Southern blot hybridization with zein cDNA and genomic sequences show that specific demethylation of zein sequences occurs only in endosperm and is restricted to the maternal complements. Steady‐state transcript accumulation of zein mRNA assessed by RNase protection assay reveals qualitative and quantitative differences among endosperm RNAs of the inbreds and of their reciprocal hybrids. Moreover, two‐dimensional gel electrophoresis of zein proteins identified polypeptides that are maternally imprinted in reciprocal crosses. These results indicate that endosperm‐specific expression of specific zein alleles may occur via parental imprinting and disclose a possible role of methylation in regulating the expression of genes differently contributed in the endosperm by the maternal and paternal genomes.