bluuebunny/crossref_metadata_2025_split huggingface dataset:
Life‐long growth of Quercus ilex L. at natural CO2 springs acclimates sulphur, nitrogen and carbohydrate metabolism of the progeny to elevated pCO2
Authors: SCHULTE M. , VON BALLMOOS P. , RENNENBERG H. , HERSCHBACH C. 
Published: March 2003

AbstractThe aim of the present study was to analyse whether offspring of mature Quercus ilex trees grown under life‐long elevated pCO2 show alterations in the physiological response to elevated pCO2 in comparison with those originating from mature trees grown at current ambient pCO2. To investigate changes in C‐ (for changes in photosynthesis, biomass and lignin see Polle, McKee & Blaschke Plant, Cell and Environment 24, 1075–1083, 2001), N‐, and S‐metabolism soluble sugar, soluble non‐proteinogenic nitrogen compounds (TSNN), nitrate reductase (NR), thiols, adenosine 5′‐phosphosulphate (APS) reductase, and anions were analysed. For this purpose Q. ilex seedlings were grown from acorns of mother tree stands at a natural spring site (elevated pCO2) and a control site (ambient pCO2) of the Laiatico spring, Central Italy. Short‐term elevated pCO2 exposure of the offspring of control oaks lead to higher sugar contents in stem tissues, to a reduced TSNN content in leaves, and basipetal stem tissues, to diminished thiol contents in all tissues analysed, and to reduced APS reductase activity in both, leaves and roots. Most of the components of C‐, N‐ and S‐metabolism including APS reductase activity which were reduced due to short‐term elevated pCO2 exposure were recovered by life‐long growth under elevated pCO2 in the offspring of spring oaks. Still TSNN contents in phloem exudates increased, nitrate contents in lateral roots and glutathione in leaves and phloem exudates remained reduced in these plants. The present results demonstrated that metabolic adaptations of Q. ilex mother trees to elevated pCO2 can be passed to the next generation. Short‐ and long‐term effects on source‐to‐sink relation and physiological and genetic acclimation to elevated pCO2 are discussed.
Genetic relationships and isozyme variability in the Heterodera avenae complex determined by isoelectrofocusing
Authors: Andrés M. F. , Romero M. D. , Montes M. J. , Delibes A. 
Published: March 2003

Isozyme variability was assessed among the principal species of the cereal cyst nematode complex to complete and enhance the information provided by classical nematode systematics, in order to clarify inter‐ and intraspecific relationships within this complex. Twenty populations of cereal cyst nematodes (Heterodera avenae, H. filipjevi, H. latipons and H. mani) were compared by means of five different isoenzymatic systems (esterase, malate dehydrogenase, phosphoglucoisomerase, phosphoglucomutase and superoxide dismutase) using isoelectrofocusing (IEF) on the electrophoretic separation. The results are in agreement with previous morphological and biochemical characterizations, which established genetic diversity between the Gotland strain and H. avenae and identified the Gotland strain with H. filipjevi. Populations from Israel, all included in the H. avenae group, exhibited well‐defined intraspecific dissimilarity. The highest degree of polymorphism was found in the H. avenae group for all five enzymatic systems studied. The H. mani population was also included in the H. avenae group by these isozyme analyses. Malate dehydrogenase, phosphoglucoisomerase and phosphoglucomutase isozymes, fractionated for the first time by IEF in the cereal cyst nematode complex, displayed a higher level of polymorphism than using conventional electrophoresis. Isoelectric focusing has proved to be a useful tool for detecting genetic diversity within and among species of the cereal cyst nematode complex and for taxonomic purposes.
Differential induction of superoxide dismutase in downy mildew‐resistant and ‐susceptible genotypes of pearl millet
Authors: Babitha M. P. , Bhat S. G. , Prakash H. S. , Shetty H. S. 
Published: March 2003

Differential induction of superoxide dismutase (SOD) in downy mildew‐resistant and ‐susceptible genotypes of pearl millet (Pennisetum glaucum) was observed on inoculation with Sclerospora graminicola. SOD activity was studied in resistant (IP18292) and susceptible (23B) pearl millet seedlings inoculated with S. graminicola. SOD activity increased by 2·3‐fold in resistant seedlings upon inoculation. SOD activity was greatest in roots, with a specific activity of 3182 U per mg protein, after inoculation. SOD activity increased in all the resistant genotypes upon inoculation with S. graminicola. Native PAGE analysis showed four isozymes of SOD, three of which (SOD‐1, ‐2 and ‐4) were Cu/Zn‐SOD, whereas isozyme SOD‐3 was Mn‐SOD. This study also revealed increased intensity of all four isozymes of SOD in the resistant genotype upon inoculation. The involvement of SOD in pearl millet (host)–downy mildew pathogen interaction is discussed.
T‐Cell Receptor Downregulation by Ceramide‐Induced Caspase Activation and Cleavage of the ζ Chain
Authors: Menné C. , Lauritsen J. P. H. , Dietrich J. , Kastrup J. , Wegener A.‐M. K. , Andersen P. S. , Ødum N. , Geisler C. 
Published: March 2003

Regulation of T‐cell receptor (TCR) cell surface expression levels is probably an important mechanism by which T‐cell responsiveness is controlled. Previously, two distinct pathways for TCR downregulation have been described. One is dependent on protein kinase C (PKC) and the leucine‐based receptor‐sorting motif (l‐based motif) of the CD3γ chain but independent of tyrosine kinases, whereas the other is dependent on the tyrosine kinase activation but independent of the PKC and the CD3γl‐based motif. In this study, we describe a new pathway for TCR downregulation distinct from both the PKC/CD3γl‐based motif‐dependent and the tyrosine kinase‐dependent pathways. This pathway is dependent on ceramide‐induced activation of caspases and correlate with caspase‐mediated cleavage of the ζ chain. Thus, a 10–15% downregulation of the TCR was induced following the treatment of the T cells with ceramide for 4 h. A close correlation between TCR downregulation, caspase activation, and cleavage of the ζ chain was found. Furthermore, the caspase inhibitors abolished the cleavage of the ζ chain and TCR downregulation in parallel with the inhibition of the caspase activity.
Heme Oxygenase is Downregulated in Stress‐Triggered and Interleukin‐12‐Mediated Murine Abortion
Authors: Zenclussen A. C. , Joachim R. , Hagen E. , Peiser C. , Klapp B. F. , Arck P. C. 
Published: March 2003

Heme oxygenases (HOs) are responsible for heme degradation. Besides their enzymatic activities, HOs are involved in tissue protection. Failing upregulation of HOs has been linked to increased necrosis in inflammatory tissues. Interestingly, previously published data indicated that mice exposed to sonic stress during early gestation show an augmented production of decidual inflammatory T‐helper 1 (Th1) cytokines, thus resulting in increased abortion rate. No data linked the Th1‐inducer interleukin (IL)‐12 with the event of abortion. As little is known about the role of HO in pregnancy maintenance, we evaluated the expression of decidual and placental HO‐1 and HO‐2 in the abortion‐prone murine mating combination CBA/J × DBA/2 J with (1) CBA/J female control mice, (2) CBA/J mice exposed to stress during early gestation and (3) CBA/J females injected with recombinant IL‐12. Decidual and placental HOs protein expression was analysed by immunohistochemistry and mRNA levels by real time polymerase chain reaction (PCR).As expected, an increased abortion rate was present in mice exposed to stress compared with the control. IL‐12 injections also boosted the abortion rate compared with control mice, mimicking the effect of stress. HOs' proteins could be detected in placenta and decidua. Real time PCR revealed lower levels of HO‐1 and HO‐2 mRNA in stress‐triggered and IL‐12‐injected mice. We conclude that increased Th1‐cytokine levels during murine pregnancy may result in low expression of HO‐1 and HO‐2, thus leading to placental necrosis and foetal rejection.
IL‐12: The Role of p40 Versus p75
Authors: Abdi K. 
Published: March 2003

Interleukin (IL)‐12p75 is a heterodimeric cytokine composed of the product of two different genes that specify p35 and p40 subunits. The prevailing view is that IL‐12 acts as a proinflammatory cytokine that bridges the innate and adaptive immune responses and skews T‐cell reactivity toward a TH1 cytokine pattern. Though the terms IL‐12 and IL‐12p40 are often used interchangeably, and measurements of the p40 chain are often interpreted as measurements of the intact p75 heterodimer, such interchangeable usage may be incorrect.In the following discussion, I will delineate an alternative hypothesis for the roles of the p40 and p75 proteins, suggesting specifically, that: (1) in vivo, secretion of free p40 precedes that of p75 in response to pathogens; (2) induction of p40 is a T‐independent response by antigen presenting cells (APCs) to early host–pathogen interactions; and (3) IL‐12p75 is a late product, whose induction requires T‐dependent signals. It is made as a result, rather than as a cause, of TH1 differentiation. Thus, it is the p40 protein, either alone or paired with other polypeptides, rather than p75, that acts as an interface between the innate and adaptive immune responses.
Multiple Mycobacterium microti Derived Lipids Stimulate iNOS Gene Expression in the J774 Murine Macrophage Cell Line
Authors: Pacheco‐García U. , Legorreta‐HerrEra M. , Hernández‐Rodríguez C. , Sánchez‐García F. J. 
Published: March 2003

The inducible nitrogen oxygen synthase (iNOS) and nitric oxide (NO) system acting in concert with superoxide radicals is recognized as a powerful macrophage microbicidal mechanism. However, experimentation with iNOS knockout mice has rendered contradictory results on the protective role of iNOS/NO in the course of mycobacterial infections. On the other hand, NO also plays an immunoregulatory role. Knowing the nature of the mycobacterial constituents that induce iNOS gene expression would help to better understand the host–parasite relationship.Lipoarabinomannan (LAM) and a 19 KDa lipoprotein are the two known mycobacterial constituents that have shown to induce iNOS. By screening a set of methanol extracted lipids from Mycobacterium microti, here we provide evidence that multiple mycobacterial molecules of lipidic nature both of intermediate and of high polarity, with free amino groups or carbohydrates but no phosphate groups as part of their structure are capable of inducing iNOS gene expression in J774 cells, thus implying a complex relationship between mycobacteria and their host immune system in regard to iNOS gene expression.
IL‐15 Induces Unspecific Effector Functions in Human Peptide‐Specific CD8+ T‐Cell Cultures
Authors: Lyngstrand S. T. , Würtzen P. A. , Ødum N. , Nissen M. H. , Röpke C. 
Published: March 2003

Antigen (Ag)‐specific CD8+ T cells are a major host defence against viral infections. In the present study, we generated human CD8+ T‐cell lines specific towards influenza matrix peptide (IMP)‐pulsed Ag‐presenting cells. We compared the effect of interleukin‐2 (IL‐2) and IL‐15 on the proliferation and cytotoxic activity of primary and secondary IMP‐specific cytotoxic T lymphocyte (CTL) culture. In primary CTL cultures, IL‐15‐induced cell expansion was considerably reduced as compared with IL‐2‐induced cell expansion, and IL‐15 favoured the outgrowth of CTLs without peptide specificity in these cultures.Secondary IMP‐specific CD8+ T cells were generated by the addition of IL‐2 during two cycles of restimulation. From the third restimulation, identical CTL cultures were expanded with either IL‐2 or IL‐15 in parallel. Cell expansion as well as Ag specificity was considerably reduced after a 5 day culture period in the presence of IL‐15. No or low CD69 expression was observed in IL‐15‐cultured CTLs, whereas IL‐2‐cultured CTLs contained high fractions of CD69+ cells. Furthermore, a high fraction of these latter cells coexpressed the cytotoxic marker CD56. However, IL‐15‐cultured CTLs exhibited cytotoxic activity without detectable expression of CD56, suggesting that CD56 is not essential for cytotoxic activity. Thus, the results presented suggest that IL‐15 favours the outgrowth of unspecific cytotoxic effector T cells.
Anastomosing river sedimentation in the Channel Country of central Australia
Authors: GIBLING MARTIN R. , NANSON GERALD C. , MAROULIS JERRY C. 
Published: March 2003

Anastomosing river plains of the Channel Country, central Australia, have aggraded slowly over the past 100 ka. Channel sediments accumulate mainly as accretionary benches of mud and sand, sandy channel‐base sheets and vegetation‐shadow deposits. The channels are laterally stable and the sediments have aggraded locally against erosional banks of tough floodplain muds. Channel sediments are profoundly affected by desiccation during dry periods and by bioturbation caused by within‐channel trees and burrowing invertebrates, especially crayfish. Excavations show that mud‐dominated channel bodies of low width:thickness ratio are generated by a combination of vertical and lateral accretion. Levees and braided surfaces, composed mainly of mud aggregates, border the channels and are activated during valley‐wide floods which lay down distal mud sheets. Floodplain muds are converted to vertisols with gilgai, deep desiccation cracks, and impregnations of carbonate and gypsum. A fixed‐channel facies model is applicable to the Channel Country river deposits. Anastomosis apparently results from the need for the system to move large volumes of water and moderate sediment loads across low‐gradient interior basins.Channels distant from upland source areas receive an abundant supply of pedogenic, sand‐sized mud aggregates generated on adjacent floodplains and reworked into braid bars during valley‐wide floods. Some quartz sand is provided from excavation of subsurface Pleistocene sands in deep channels and waterholes and from aeolian dunes on the floodplains. Adjacent gibber plains supply some gravel to the system.
Rapid in situ silicification of microbes at Loburu hot springs, Lake Bogoria, Kenya Rift Valley
Authors: RENAUT R. W. , JONES B. , TIERCELIN J.‐J. 
Published: March 2003

Microbial mats, located along the margins of hot‐spring pools and outflow channels at Lake Bogoria, Kenya, are commonly silicified forming friable laminated crusts. Columnar microstromatolites composed of silica and calcite are also forming at several springs in sites of oscillating water level or spray. Silicification of the microbes involves impregnation of organic tissue by very fine amorphous silica particles and encrustation by small (< 2 μm) silica spheroids. Rapid silicification of the microbes, which may begin while some are still alive, can preserve sheaths and in some examples, the filaments, capsules and cells. Although this provides evidence of their general morphology, the biological features that are required for taxonomic identifications are commonly poorly preserved.The silica precipitation results mainly from evaporative concentration and rapid cooling of spring waters that have been drawn upward through the mats and microstromatolites by capillary processes. Almost all the silica at the Loburu springs nucleates on microbial substrates. This affinity of silica for functional groups on microbial surfaces contributes to the rapid silicification of the microbes and their preservation in modern and ancient cherts.
Phylogeny of New Zealand hepialid moths (Lepidoptera: Hepialidae) inferred from a cladistic analysis of morphological data
Authors: Brown B. , Dugdale J. S. , Emberson R. M. , Paterson A. M. 
Published: March 2003

SummaryThe phylogeny of the New Zealand hepialid moths was estimated from a cladistic analysis of sixty‐three morphological characters, from all life cycle stages. One hundred and sixteen maximum parsimony trees were produced. The phylogenetic reconstruction indicated that the currently recognized generic concepts, and the four informal lineages hypothesized in a previous morphological taxonomic revision, were monophyletic. The relationships of species within genus Wiseana were not fully resolved. Analysis of a data set of thirty‐nine adult male characters from the New Zealand taxa and the Australian genera Jeana, Oxycanus and Trictena supported the monophyly of the New Zealand ‘Oxycanus’ s.s lineage.
Ultra‐high pressure (P > 6 GPa) garnet peridotites in Western Norway: exhumation of mantle rocks from > 185 km depth
Authors: Van Roermund  , Drury  
Published: March 2003

We report here for the first time the occurrence of relics of majoritic garnet within orogenic garnet peridotites from Otrøy, Western Gneiss Region, Norway. The microstructural evidence consists of two‐pyroxene exsolution from garnet. Majoritic garnets are only stable at depths greater than 150 km. Estimates of the initial composition of the majoritic garnets imply pressures of 6–6.5 GPa indicating that the Otrøy peridotites were derived from depths > 185 km. Mineral‐chemical data indicate that the present mineral compositions equilibrated at mantle conditions around 805 ± 40 °C and 3.2 ± 0.2 GPa. Estimates of the initial pressure temperature (PT) conditions and PTtime (t) path are consistent with a multistage, multiorogenic exhumation history with upwelling of hot asthenosphere up to ≈ 100 km in the Pre‐Cambrian followed by subsequent crustal emplacement and exhumation during the Caledonian orogeny.
PCR‐aided genomic sequencing of 5' subterminal sequences of the maize transposable element Activator (Ac) in transgenic tobacco plants.
Authors: Ott T , Nelsen‐Salz B , Doring HP 
Published: March 2003

SummaryThe maize transposable element Activator (Ac) carries subterminal CpG‐ rich sequences which are essential for the transposition of the element. It has previously been shown that the methylation of certain sequences contained in this region can alter their ability to interact with the Ac‐encoded protein. The novel hypothesis that the methylation of subterminal Ac sequences is required for transposition was tested. Approximately 150 bp of the 5' subterminal region of the Ac element was examined for the presence of 5‐methylcytosines by the ligation‐mediated polymerase chain reaction (LMPCR)‐aided genomic sequencing method. The methylation status of 22 and 39 cytosines on either strand of the DNA were analysed in each of five different transgenic tobacco cultures carrying transposable Ac sequences. Ten micrograms of tobacco DNA were used for each base‐specific cleavage reaction before amplification by LMPCR. All but one of the cytosines were unmethylated. Only a minor fraction of the Ac molecules was methylated at one cytosine residue. It is concluded that DNA methylation at the tested Ac sequences is not required for the transposability of Ac or Ds elements in tobacco cells.
Potato virus X as a vector for gene expression in plants
Authors: Chapman Sean , Kavanagh Tony , Baulcombe David 
Published: March 2003

SummaryThe suitability of potato virus X (PVX) as a gene vector in plants was tested by analysis of two viral constructs. In the first, the GUS gene of Escherichia coli was substituted for the viral coat protein gene. In the second, GUS was added into the viral genome coupled to a duplicated copy of the viral promoter for the coat protein mRNA. The viral construct with the substituted coat protein gene accumulated poorly in inoculated protoplasts and failed to spread from the site of infection in plants. These results suggest a role for the viral coat protein in key stages of the viral infection cycle and show that gene replacement constructs are not suitable for the production of PVX‐based gene vector. The construct with GUS coupled to the duplicated promoter for coat protein mRNA also accumulated less well in protoplasts than the unmodified PVX, but did infect systemically and directed high level synthesis of GUS in inoculated and systemically infected tissue. Although there was some genome instability in the PVX construct, much of the viral RNA in the systemically infected tissue had retained the foreign gene insertion, especially in infected Nicotiana clevelandii plants. These data point to a general utility of PVX as a vector for unregulated gene expression in plants.
Cis‐analysis of a seed protein gene promoter: the conservative RY repeat CATGCATG within the legumin box is essential for tissue‐specific expression of a legumin gene
Authors: Bäumlein Helmut , Nagy† Istvan , Villarroel Raimundo , Inzé Dirk , Wobus Ulrich 
Published: March 2003

SummaryA 2.4 kb fragment containing the 5 ‐flanking region and the 5′‐noncoding sequence of the Vicia faba legumin gene LeB4 mediates high level seed‐specific expression in transgenic tobacco plants. Deleted derivatives of this legumin upstream sequence were fused to the npt‐ll reporter gene to determine the tissue‐specific activity of the chimeric constructs in stably transformed tobacco plants. The results indicate the presence of positive regulatory, enhancer‐like cis elements within 566 bp of the upstream sequence. Most importantly, however, these elements are only fully functional in conjunction with the core motif CATGCATG of the legumin box around position ‐95, since destruction of the motif by a 6 bp deletion in an otherwise intact 2.4 kb upstream sequence drastically reduces expression in seeds. At the same time, low level expression in leaves is observed. The occurrence of similar CATGCATG consensus cis elements with alternating purine and pyrimidine base pairs in front of several other plant genes suggests a functional role of the motif in a wider range of plant promoters.
Identification of an S‐locus glycoprotein allele introgressed from B. napus ssp. rapifera to B. napus ssp. oleifera
Authors: Goring Daphne R. , Banks Paul , Fallis Lynne , Baszczynski Chris L. , Beversdorf Wallace D. , Rothstein Steven J. 
Published: March 2003

SummarySelf‐incompatible Brassica napus ssp. oleifera lines were generated by introgressing the S‐locus from the self‐incompatible B. napus ssp. rapifera Z line into the self‐compatible cultivars, Topas and Regent, resulting in T2 and R2, respectively. Screening of a cDNA library made from R2 stigma RNA produced several candidate SLG (S‐locus glycoprotein) cDNAs. One of the cDNAs, A14, was found to be represented in only the R2, T2 and Z lines. In addition, the corresponding A14 gene was demonstrated to segregate with the T2 self‐incompatibility phenotype in an F2 population derived from a cross between T2 and Topas, and to exhibit high mRNA levels in the stigmas prior to anthesis. Sequence analysis of the A14 cDNA revealed close homology to B. oleracea SLG alleles associated with a Class I high activity self‐incompatibility phenotype.
Soluble isoforms of starch synthase and starch‐branching enzyme also occur within starch granules in developing pea embryos
Authors: Denyer Kay , Sidebottom Christopher , Hylton Christopher M. , Smith Alison M. 
Published: March 2003

Developing wild‐type pea embryos contain two major isoforms of starch synthase and two isoforms of starch‐branching enzyme. One of the starch synthases and both starch‐branching enzymes occur both in the soluble fraction and tightly bound to starch granules. The other starch synthase, which is very similar to the waxy proteins of other species, is exclusively granule‐bound. It is inactive when solubilized in a native form from starch granules, but activity is recovered when the SDS‐denatured protein is reconstituted from polyacrylamide gels.Evidence is presented which indicates that all of these proteins become incorporated within the structure of the granule as it grows. It is proposed that the granule‐bound waxy protein is active in vivo at the granule surface, whereas the remaining proteins are active in the soluble fraction of the amyloplast. The proteins become trapped within the granule matrix as the polymers they synthesize crystallize around them, and they probably play no further part in polymer synthesis.