bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phylogeny of Culicomorpha (Diptera)
Authors: Sæther O. A. 
Published: March 2003

SummaryThe phylogeny of the families of Culicomorpha and their closest relatives are cladistically reinvestigated adding published information from several sources. A revised data matrix is presented and some characters are discussed. Different outgroups and options used, characters unordered or ordered, the results reweighted or not and the results discussed. Nymphomyiidae in all cladograms, alone or together with Thaumaleidae, forms the sister group of the traditional Culicomorpha and should be included in this infraorder as suggested by others. Superfamily Chironomoidea is not monophyletic as Thaumaleidae or Nymphomyiidae + Thaumaleidae form the sister group to the remaining traditional Culicomorpha. The mutual relationships of Chironomidae, Simuliidae and Ceratopogonidae are variable between cladograms. They form a monophyletic group with Chironomidae and Simuliidae as sister groups when characters are unordered and reweighted or when some characters are ordered, others unordered and the result reweighted. When the characters are ordered, or when a combination of ordered and unordered are used they form a Hennigian comb with the phyletic sequence Chironomidae/Ceratopogonidae/Simuliidae. When characters are ordered and reweighted the phyletic sequence is Chironomidae/Simuliidae/Ceratopogonidae. Culicoidea is monophyletic in all cladograms, but the division into superfamilies is not warranted.
A cladistic analysis of Erythracarinae (Acarina: Prostigmata: Anystidae), with the description of a new genus
Authors: Otto Jürgen C. 
Published: March 2003

SummaryA cladistic analysis of sixty erythracarine species is presented and used to justify recent nomenclatorial changes to the classification of erythracarine genera. Erythracarinae is redescribed, and a new diagnosis for the subfamily and a key to the included genera are presented. Neotarsolarcus is recognized as a junior synonym of Tarsolarkus, which is recorded for the first time from North America. A new genus, Pedidromus, with six new species (P. agitatus sp.n. P. curiosus sp.n., P. durongensis sp.n., P. peliculus sp.n., P. pilotrix sp.n., P. velox sp.n.) is described.
From thickening to extension in the Variscan belt — kinematic evidence from Sardinia (Italy)
Authors: Conti P. , Carmignani L. , Oggiano G. , A.  , A.  
Published: March 2003

The Variscan nappe stack of SE Sardinia originated as a result of several stages of nappe imbrication during the Lower Carboniferous phases of the Variscan orogeny. The crustal shortening caused regional SSW‐and W‐directed thrusting, greenschist facies metamorphism and open‐to‐isoclinal polyphase folding. The final stage of shortening produced large‐scale antiforms and synforms.Post‐collisional deformation resulted in inversion of earlier thrusts as normal faults, development of low‐angle normal faults, and refolding of earlier foliation and thrust planes by asymmetric folds with subhorizontal axial planes. Facing directions of these latest folds are directed horizontally outward from the hinge zones of main antiforms, suggesting that they cannot be regarded as parasitic folds of the latest thickening phase, but instead are the consequence of vertical shortening during gravitational collapse of dome‐like km‐scale antiforms, leading to denudation of antiformal culminations.
The carboxy‐terminal end of glycolate oxidase directs a foreign protein into tobacco leaf peroxisomes.
Authors: Volokita M 
Published: March 2003

SummaryThe carboxy‐terminal residues of several peroxisomal proteins were shown to act as a peroxisomal targetting signal. This study was conducted to test whether the C‐terminus of glycolate oxidase, a key enzyme in the glycolate metabolism pathway, is functioning as a targetting signal that directs proteins into plant leaf peroxisomes. A chimeric gene coding for a fusion protein composed of the C‐terminal‐ truncated beta‐glucuronidase, a synthetic linker of four amino acids and the last six C‐terminal amino acids of glycolate oxidase, was constructed. Transformation of tobacco plants with the chimeric gene resulted in expression of beta‐glucuronidase enzymic activity. About 50% of the transgenic beta‐glucuronidase activity was localized to the peroxisomes. The results indicate that the six C‐terminal amino acid residues of glycolate oxidase act as a targetting signal that is recognized by leaf peroxisomes.
The ptl1 gene expressed in the transmitting tissue of Antirrhinum encodes an extensin‐like protein.
Authors: Baldwin TC , Coen ES , Dickinson HG 
Published: March 2003

Summaryptl1, a gene expressed specifically in pistil transmitting tissue of Antirrhinum flowers, encodes a protein with similarity to plant extensins. The protein is rich in proline (28%) and serine (9%) and contains several proline‐rich repetitive amino acid motifs found in other extensin‐like proteins. The presence of three consensus N‐ glycosylation sites indicates that it is probably glycosylated. RNA blots show that the ptl1 transcript is abundant in mature pistillar tissue but absent from immature flower buds and all other plant organs tested. In‐situ localization of mRNA demonstrates that ptl1 expression is confined to the transmitting tissue of the style and stigma. The presence of a putative signal peptide at the N‐terminus of the protein, taken together with the expression pattern, indicates that the ptl1 product may be secreted into the extracellular matrix of the transmitting tissue. The possible contributions of the ptl1 product to the physical properties of the transmitting tissue are considered in the light of current views on extensin structure and function.
Isolation of an asparagus intracellular PR gene (AoPR1) wound‐responsive promoter by the inverse polymerase chain reaction and its characterization in transgenic tobacco
Authors: Warner Simon A. J. , Scott Rod , Draper John 
Published: March 2003

SummaryThe Asparagus officinalis intracellular PR1 (AoPR1) gene is expressed in response to wounding and pathogen attack. We utilized the inverse polymerase chain reaction (IPCR) to isolate the cis‐acting regulatory sequences of the AoPR1 gene following unsuccessful attempts to identify hybridizing clones in genomic libraries. Sequence analysis of two IPCR products revealed that a 347 bp intron was present in the AoPR1 gene and that it was probable that the AoPR1 regulatory sequence had been amplified. To test the AoPR1 cis‐acting sequences for biological function a translational fusion was constructed with the β‐glucuronidase (GUS) reporter gene and tested in tobacco. These data demonstrated that sequences 982 bp from the probable start of transcription are sufficient to direct wound‐inducible transcription and that there is no signal peptide encoded by the first 31 residues of the predicted AoPR1 protein. Histochemical localization of GUS activity in transgenic tobacco demonstrated strong activity localized to wound and pathogen invasion sites. GUS activity was also found in mature pollen grains.
Expression of the S‐locus receptor kinase multigene family in Brassica oleracea
Authors: Kumar Vinod , Trick Martin 
Published: March 2003

SummaryThe S‐receptor kinase (SRK) gene which is implicated in the self‐incompatibility system of Brassica oleracea is one member of a large and complex family of similar sequences. Genomic and cDNA clones were isolated for the authentic, S‐linked SRK29 gene and its DNA sequence determined. Reverse transcriptase PCR (RT‐PCR) was used to detect the expression of SRK,29 and other members of the family in stigma, leaf and root tissues. The SRK was found to be stigma‐specific whereas, for instance, K3 transcripts appeared in all three tissues. The RT‐PCR analysis also demonstrated the existence of partially processed intermediates for several of the kinase transcripts and, in the case of SRK29, a product apparently resulting from the splicing of a cryptic intron. RFLP analysis of an F2 family segregating for the S29 allele was used to show S‐linkage for the SRK and possibly for the K2 sequence. The K8 kinase probe also revealed a minor RFLP which segregated with the S‐locus.
The intravacuolar organic matrix associated with calcium oxalate crystals in leaves of Vitis
Authors: Webb Mary Alice , Cavaletto John M. , Carpita Nicholas C. , Lopez Linda E. , Arnott Howard J. 
Published: March 2003

SummaryIn Vitis (grape) calcium oxalate crystals form in a needle‐like morphology unique to plants, presenting an intriguing system of biological control over mineral formation. Crystals develop within an organic matrix which appears to provide control over the sites and forms of crystal deposition; however, little is known about the chemical nature of the matrix. A procedure has been developed to isolate crystals along with their associated intravacuolar matrix from leaves of grape, and studies have been initiated into the chemical composition of the matrix by characterizing elemental content, carbohydrates, and protein. The isolated matrix consisted of two structural phases, membrane chambers enclosing developing crystals, and a water‐soluble phase surrounding the crystal chambers. Elemental analysis detected substantial calcium and potassium, as well as some iron in the water‐soluble phase. Analysis of the water‐soluble matrix by GC‐MS showed that it contained an unusual polymer with novel glucuronic acid linkages. In addition, linkage analysis indicated 5‐linked arabinans, arabinogalactan, and various mannosyl units typical of complex carbohydrates of N‐linked glycoproteins. SDS—PAGE analysis of the water‐soluble matrix and crystal chambers showed that each had distinct banding profiles in silver‐stained gels, with prominent 60 and 70 kDa polypeptides in crystal chamber extracts. Demineralization studies provided direct evidence that the isolated matrix promotes crystal nucleation. The findings about the organic matrix associated with calcium oxalate crystals in grape are discussed in relation to crystal nucleation and growth and features shared with animal and microbial biomineralization systems.
Protease‐sensitive thylakoidal import machinery for the Sec‐, ΔpH‐ and signal recognition particle‐dependent protein targeting pathways, but not for CFoII integration
Authors: Robinson David , Karnauchov Ivan , Herrmann Reinhold G. , Klösgen Ralf Bernd , Robinson Colin 
Published: March 2003

SummaryNuclear‐encoded proteins are targeted into and across the thylakoid membrane by a surprising variety of mechanisms. Distinct Sec‐ and ΔpH‐dependent mechanisms have been shown to operate for lumenal proteins, and an integral membrane protein, LHCP, has been shown to insert via a signal recognition particle‐dependent route. Integration of a further membrane protein, CFoII, requires neither soluble factors nor energy sources, prompting speculation of a spontaneous insertion mechanism. Although the requirements for soluble factors and energy sources have been determined in some detail, much less is known of the events taking place at the membrane surface. This report examines whether thylakoid proteins are involved in each of these pathways, by testing the effects of trypsin on the capacity of isolated thylakoids to import proteins. Because all of the pathways rely to some extent on the thylakoidal ΔpH, and a light‐induced ΔpH is easily destroyed by proteolysis, the conditions under which reverse action of the ATP synthase in the dark generates a high ΔpH even after proteolysis of thylakoids have been established. This system is used to show that protease‐sensitive thylakoidal import machinery is crucial for the ΔpH‐, Sec‐ and signal recognition particle‐dependent pathways, but not for integration of CFoII.
The NADH‐binding subunit of respiratory chain complex I is nuclear‐encoded in plants and identified only in mitochondria
Authors: Grohmann Lutz , Rasmusson Allan G. , Heiser Volker , Thieck Oliver , Brennicke Axel 
Published: March 2003

In higher plants, genes for subunits of respiratory chain complex I (NADH:ubiquinone oxidoreductase) have so far been identified solely in organellar genomes. At least nine subunits are encoded by the mitochondrial DNA and 11 homologues by the plastid DNA. One of the ‘key’ components of complex I is the subunit binding the substrate NADH. The corresponding gene for the mitochondrial subunit has now been cloned and identified in the nuclear genome from potato (Solanum tuberosum). The mature protein consists of 457 amino acids and is preceded by a mitochondrial targeting sequence of 30 amino acids. The protein is evolutionarily related to the NADH‐binding subunits of complex I from other eukaryotes and is well conserved in the structural domains predicted for binding the substrate NADH, the FMN and one iron‐sulphur cluster. Expression examined in different potato tissues by Northern blot analysis shows the highest steady‐state mRNA levels in flowers.Precursor proteins translated in vitro from the cDNA are imported into isolated potato mitochondria in a ΔΨ‐dependent manner. The processed translation product has an apparent molecular mass of 55 kDa, identical to the mature protein present in the purified plant mitochondrial complex I. However, the in‐vitro translated protein is not imported into isolated chloroplasts. To further investigate whether the complex I‐like enzyme in chloroplasts contains an analogous subunit for binding of NAD(P)H, different plastid protein fractions were tested with a polyclonal antiserum directed against the bovine 51 kDa NADH‐binding subunit. In none of the different thylakoid or stroma protein fractions analysed were specific crossreactive polypeptides detected. These results are discussed particularly with respect to the structure of a potential complex I in chloroplasts and the nature of its acceptor site.
Isolation and characterization of a cDNA encoding mitochondrial chaperonin 10 from Arabidopsis thaliana by functional complementation of an Escherichia coli groES mutant
Authors: Koumoto Yasuko , Tsugeki Ryuji , Shimada Tomoo , Mori Hitoshi , Kondo Maki , Hara‐Nishimura Ikuko , Nishimura Mikio 
Published: March 2003

SummaryChaperonin (Cpn) is one of the molecular chaperones. Cpn10 is a co‐factor of Cpn60, which regulates Cpn60‐mediated protein folding. It is known that Cpn10 is located in mitochondria and chloroplasts in plant cells. The Escherichia coli homologue of Cpn10 is called GroES. A cDNA for the Cpn10 homologue was isolated from Arabidopsis thaliana by functional complementation of the E. coli groES mutant. The cDNA was 647 bp long and encoded a polypeptide of 98 amino acids. The deduced amino acid sequence showed approximately 50% identity to mammalian mitochondrial Cpn10s and 30% identity to GroES. A Northern blot analysis revealed that the mRNA for the Cpn10 homologue was expressed uniformly in various organs and was markedly induced by heat‐shock treatment. The Cpn10 homologue was constitutively expressed in transgenic tobaccos. Immunogold and immunoblot analyses following the subcellular fractionation of leaves from transgenic tobaccos revealed that the Cpn10 homologue was localized in mitochondria and accumulated at a high level in transgenic tobaccos.
Microinjection of fluorescent tubulin into plant cells provides a representative picture of the cortical microtubule array
Authors: Wymer Carol L. , Shaw Peter J. , Warn Richard M. , Lloyd Clive W. 
Published: March 2003

SummaryBy microinjecting rhodamine‐labelled tubulin into living plant cells, it is possible to observe microtubules (MTs) directly and to see how the cortical array reorganizes itself. The validity of the conclusions drawn from such observations depends upon the assumption that most, if not all, of the native MTs are dynamic and incorporate labelled tubulin. However, if arrays also contain MTs that are not exchanging tubulin subunits, such MTs will remain unlabelled, and the labelled MT population will be under‐representative of the whole array. To address this potential problem, we microinjected pea epidermal cells with rhodamine‐labelled tubulin, then fixed the cells and used fluorescein‐conjugated antibodies against tubulin to detect the entire MT array. The two fluorescent patterns corresponded well, confirming that the MTs labelled with exogenous tubulin were evenly distributed throughout the entire array. Also, by comparing the MT image before and after aldehyde fixation, we observed that, although some of the MTs were lost in the procedure, the fixation was able to preserve the arrangement of MTs seen in the living cell. We conclude that fluorescence analogue cytochemistry provides a valid representation of the entire cortical MT array.
The enzyme involved in sulfation of the turgorin, gallic acid 4‐O‐(β‐d‐glucopyranosyl‐6′‐sulfate) is pulvini‐localized in Mimosa pudica
Authors: Varin Luc , Chamberland Héléne , Lafontaine Jean Guy , Richard Martine 
Published: March 2003

SummaryA sulfotransferase (ST) which catalyzes the transfer of sulfate from 3′‐phosphoadenosine 5′‐phosphosulfate (PAPS) to gallic acid glucoside was characterized from microsomal preparations of Mimosa pudica. The product of the reaction was found to co‐elute on HPLC with the periodic leaf movement factor 1 (PLMF‐1) (gallic acid β‐d‐gluco‐pyranosyl‐6′‐sulfate). The distribution of the enzyme activity was restricted to plasma membrane preparations from primary, secondary and tertiary pulvini. The M. pudica ST activity was inhibited in a dose‐dependent manner in the presence of an antibody raised against the flavonol 3‐sulfotransferase of Flaveria chloraefolia, suggesting structural similarities between the two proteins. Western blot analysis of M. pudica protein extracts using these antibodies indicated the presence of a cross‐reactive polypeptide with an apparent molecular mass of 42 000 Da whose distribution correlates with the presence of the gallic acid glucoside ST activity. Indirect immunogold labeling of resin‐embedded sections from tertiary pulvini showed a specific localization of gold particles on the sieve‐tube plasma membranes. The label distribution was uniform and other cellular organelles and membrane systems displayed little or no labeling. The results of the Western blot and immunocytochemical studies are consistent with the detection of the gallic acid glucoside ST activity in plasma membrane preparations of M. pudica pulvini cells. The specific tissue distribution of the ST in motor organ phloem cells suggests that this is the site of synthesis and/or accumulation of PLMF‐1 and supports the proposed hypothesis that PLMF‐1 may be acting as a chemical signal during the seismonastic response of M. pudica.
Post‐transcriptional gene silencing of ACC synthase in tomato results from cytoplasmic RNA degradation
Authors: Lee Kathleen Y. , Baden Catherine , Howie William J. , Bedbrook John , Dunsmuir Pamela 
Published: March 2003

SummaryTransgenic tomato plants with the coding region of a predominantly fruit specific ACC synthase gene (LE‐ACS2) driven by the CAMV35S promoter, fall into two phenotypic classes: (i) epinastic plants and (ii) plants which appear vegetatively normal with ripening impaired fruit. In leaf tissue from epinastic plants the transgene RNA pool is high, and in the vegetatively normal plants the transgene transcript level is very low. While the epinastic phenotype results from the expected high level expression of the ACC synthase transgene throughout the plant, the vegetatively normal, ripening impaired phenotype is a consequence of the silencing of both the transgene and the corresponding endogenous gene. As in several other cases of gene silencing, the mechanism is post‐transcriptional. Transgene RNA pools are similar in nuclei of epinastic and vegetatively normal tissue. However, the transgene mRNA pool is dramatically reduced in the cytoplasm of vegetatively normal plants, and furthermore, this reduction results from degradation from the 3′ end of the transcript. This degradation probably occurs on the polysomes where the transgene transcripts are localized.
Blocking polyadenylation of mRNA in the chloroplast inhibits its degradation
Authors: Lisitsky Irena , Klaff Petra , Schuster Gadi 
Published: March 2003

SummaryThe addition of poly(A)‐rich sequences to endonuclease cleavage products of chloroplast mRNA has recently been suggested to target the polyadenylated RNA for rapid exonucleolytic degradation. This study analyzed whether the addition of a poly(A)‐rich tail to RNA molecules is required for degradation by chloroplast exonuclease(s). In lyzed chloroplasts from spinach, addition of the polyadenylation inhibitor, cordycepin triphosphate (3′‐dATP), inhibited the degradation of psbA and rbcL mRNAs. Furthermore, degradation intermediates generated by endonucleolytic cleavages accumulated. Similar results were obtained when yeast tRNA was added to the mRNA degradation system as a non‐specific exoribonuclease inhibitor. Nevertheless, the stabilization mechanisms differ: while tRNA directly affects the exonuclease activity, 3′dATP has an indirect effect by inhibiting polyadenylation. The results indicate that the addition of poly(A)‐rich sequences to endonucleolytic cleavage products of chloroplast mRNA is required to target these RNAs for rapid exonucleolytic degradation. Together with previous work, the data reported here support a model for mRNA degradation in the chloroplast in which endonucleolytic cleavages are followed by the addition of poly(A)‐rich sequences to the proximal cleavage products, targeting these RNAs for rapid exonucleolytic decay.
Oxidative cross‐linking of plasma membrane arabinogalactan proteins
Authors: Kjellbom Per , Snogerup Lars , Stöhr Christine , Reuzeau Christophe , McCabe Paul F. , Pennell Roger I. 
Published: March 2003

SummaryMonoclonal antibodies which recognize carbohydrate in arabinogalactan proteins (AGPs) have revealed that certain carbohydrate epitopes at the outer plasma membrane surface are demonstratively regulated. Some epitomes are expressed according to cell position, and AGES are thought to play a role in cell—cell interaction during development. This study demonstrates that sugar beet plasma membranes contain two subagencies of AGES, with apparent molecular masses of 82 and 97 kDa, and that each subfamily consists of a small number of acidic AGP isoforms. Excision of leaves generates three additional AGP complexes with apparent molecular masses of 120, 170 and 210 kDa, with the 170 kDa complex being the major form induced by excision. The addition of millimolar concentrations of H2O2 to a partially purified fraction of the 82 and 97 kDa AGPs also generates AGP complexes, with the 170 kDa complex as the major form. These results indicate that the plasma membrane AGPs are a target for endogenous H2O2.
In transformed tobacco cells the apoplasmic invertase inhibitor operates as a regulatory switch of cell wall invertase
Authors: Krausgrill Silke , Greiner Steffen , Köster Ulrike , Vogel Rolf , Rausch Thomas 
Published: March 2003

Summary Agrobacterium tumefaciens‐transformed tobacco suspension‐cultured cells (TSCC) exhibit no significant quantitative changes of cell wall invertase protein (CWI) during a culture period of 40 days, whereas CWI activity decreases strongly between 10 and 30 days after cell transfer to fresh medium. Western blot analysis revealed that the apoplasmic invertase inhibitor (INH) is equally expressed throughout the entire culture period. When apoplasmic protein fractions from 4 and 28 days old cell cultures are chromatographed on Concanavalin A(ConA)‐Sepharose, the non‐glycosylated INH always coelutes with the ConA‐bound fraction, suggesting that (i) INH and the glycosylated CWI form a complex in the apoplasmic space, and (ii) INH binding is not sufficient for CWI inhibition. The high specificity of INH binding to CWI was confirmed by native cathodic polyacrylamide gel electrophoresis. Expression analysis of CWI and INH indicates that, at least during certain stages of plant development (seedlings, roots of adult plants), CWI activity may be modulated by INH, the latter operating as a regulatory switch.