bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biogeographical tests of the vicariance model in Mediterranean land snails
Authors: Hausdorf Bernhard , Hennig Christian 
Published: May 2006

AbstractAim To investigate the importance of vicariance in shaping land snail faunas.Location Three data sets of Mediterranean land snails were analysed: Helicoidea of the Iberian Peninsula and the complete land snail faunas of the central and eastern Aegean Islands and of Israel and Palestine.Methods The vicariance model predicts a clustering of species ranges. We tested for clustering of species ranges with a Monte Carlo simulation. For this simulation we used a null model that generates range data sets in such a way that their range size distribution, their species richness distribution and the spatial autocorrelation of the ranges approximate the parameters in the real data set. Biotic elements (clusters of species ranges) were delimited with model‐based Gaussian clustering. A second prediction of the vicariance model is that closely related species belong to different biotic elements. This was tested with a chi‐squared test.Results The distribution areas of the Iberian Helicoidea and the Israeli/Palestinian land snails are significantly clustered. The same is true for Israeli/Palestinian land snail species belonging to groups with geographically restricted species. However, the clustering is not significant in the complete central and eastern Aegean land snail data set, the Iberian Helicoidea species, and the central and eastern Aegean land snails belonging to groups with geographically restricted species. Contrary to the prediction of the vicariance model, closely related Iberian Helicoidea species and Israeli/Palestinian land snails belong significantly more often to the same biotic element than expected by chance. The null hypothesis that closely related species are homogeneously distributed across biotic elements cannot be rejected only for the data set that includes the Israeli/Palestinian land snails belonging to groups with geographically restricted species.Main conclusions The patterns found in the central and eastern Aegean land snail and the Iberian Helicoidea data sets do not correspond with the predictions of the vicariance model. This indicates that speciation modes other than vicariance were frequent, or that the distribution areas of many species in these faunas were largely modified by extensive post‐speciation dispersal and/or regional extinction. Hardly any possible vicariance events that might have contributed to the origin of the observed biotic elements in the Israeli/Palestinian land snail fauna could be identified. On the contrary, the biotic elements of the Israeli/Palestinian land snail fauna correspond with ecological factors. Vicariance has had only a limited influence on current biogeographical patterns in Mediterranean land snails.
Chlamydia trachomatis‐derived deubiquitinating enzymes in mammalian cells during infection
Authors: Misaghi Shahram , Balsara Zarine R. , Catic Andre , Spooner Eric , Ploegh Hidde L. , Starnbach Michael N. 
Published: May 2006

SummaryChlamydia trachomatis is an obligate intracellular bacterium that causes a variety of diseases in humans. C. trachomatis has a complex developmental cycle that depends on host cells for replication, during which gene expression is tightly regulated. Here we identify two C. trachomatis proteases that possess deubiquitinating and deneddylating activities. We have designated these proteins ChlaDub1 and ChlaDub2. The genes encoding ChlaDub1 and ChlaDub2 are present in all Chlamydia species except for Chlamydia pneumoniae, and their catalytic domains bear similarity to the catalytic domains of other eukaryotic ubiquitin‐like proteases (Ulp). The C. trachomatis DUBs react with activity‐based probes and hydrolyse ubiquitinated and neddylated substrates. ChlaDub1 and ChlaDub2 represent the first known bacterial DUBs that possess both deubiquitinating and deneddylating activities.
Synthesis of low molecular weight thiols in response to Cd exposure in Thlaspi caerulescens
Authors: HERNÁNDEZ‐ALLICA J. , GARBISU C. , BECERRIL J. M. , BARRUTIA O. , GARCÍA‐PLAZAOLA J. I. , ZHAO F. J. , MCGRATH S. P. 
Published: May 2006

ABSTRACTIn this study, we investigated the accumulation of phytochelatins (PCs) and other low molecular weight (LMW) thiols in response to Cd exposure in two contrasting ecotypes differing in Cd accumulation. Using a root elongation test, we found that the highly accumulating ecotype Ganges was more tolerant to Cd than the low Cd‐accumulation ecotype Prayon. l‐buthionine‐(S,R)‐sulphoximine (BSO), a potent inhibitor of the γ‐glutamylcysteine synthetase (γ‐ECS) (an enzyme involved in the PC biosynthetic pathway), increased the Cd sensitivity of Prayon, but had no effect on Ganges. Although PC accumulation increased in response to Cd exposure, no significant differences were observed between the two ecotypes. Cd exposure induced a dose‐dependent accumulation of both Cys and a still unidentified LMW thiol in roots of both ecotypes. Root accumulation of Cys and this thiol was higher in Ganges than in Prayon; the ecotypic differences were more pronounced when the plants were treated with BSO. These findings suggest that PCs do not contribute to the Cd hypertolerance displayed by the Ganges ecotype of Thlaspi caerulescens, whereas Cys and other LMW thiols might be involved.
Guard cells in albino leaf patches do not respond to photosynthetically active radiation, but are sensitive to blue light, CO2 and abscisic acid
Authors: ROELFSEMA M. ROB G. , KONRAD KAI R. , MARTEN HOLGER , PSARAS GEORGE K. , HARTUNG WOLFRAM , HEDRICH RAINER 
Published: May 2006

ABSTRACTStomatal openings can be stimulated by light through two signalling pathways. The first pathway is blue light specific and involves phototropins, while the second pathway mediates a response to photosynthetically active radiation (PAR). This second pathway was studied with the use of albino Vicia faba plants and variegated leaves of Chlorophytum comosum. Treatment of V. faba with norflurazon (Nf) inhibits the synthesis of carotenoids and leads to albino leaves with guard cells that lack functional green chloroplasts. Guard cells in albino leaf patches of C. comosum, however, do contain photosynthetically active chloroplasts. Stomata in albino leaf patches of both plants did not respond to red light, although blue light could still induce stomatal opening. This shows that the response to PAR is not functioning in albino leaf patches, even though guard cells of C. comosum harbour chloroplasts. Stomata of Nf‐treated plants still responded to CO2 and abscisic acid (ABA). The size of Nf‐treated guard cells was increased, but impalement studies with double‐barrelled microelectrodes revealed no changes in ion‐transport properties at the plasma membrane of guard cells. Blue light could hyperpolarize albino guard cells by triggering outward currents with peak values of 37 pA in albino plants and 51 pA in green control cells. Because of the inhibition of carotenoid biosynthesis, Nf‐treated V. faba plants contained only 4% of the ABA content found in green control plants. The ABA dose dependence of anion channel activation in guard cells was shifted in these plants, causing a reduced response to 10 µm ABA. These data show that despite the dramatic changes in physiology caused by Nf, the gross responsiveness of guard cells to blue light, CO2 and ABA remains unaltered. Stomata in albino leaf patches, however, do not respond to PAR, but require photosynthetically active mesophyll cells for this response.
Transcriptional regulators of stamen development in Arabidopsis identified by transcriptional profiling
Authors: Mandaokar Ajin , Thines Bryan , Shin Byongchul , Markus Lange B. , Choi Goh , Koo Yeon J. , Yoo Yung J. , Choi Yang D. , Choi Giltsu , Browse John 
Published: May 2006

SummaryIn Arabidopsis, jasmonate is required for stamen and pollen maturation. Mutants deficient in jasmonate synthesis, such as opr3, are male‐sterile but become fertile when jasmonate is applied to developing flower buds. We have used ATH1 oligonucleotide arrays to follow gene expression in opr3 stamens for 22 h following jasmonate treatment. In these experiments, a total of 821 genes were specifically induced by jasmonate and 480 genes were repressed. Comparisons with data from previous studies indicate that these genes constitute a stamen‐specific jasmonate transcriptome, with a large proportion (70%) of the genes expressed in the sporophytic tissue but not in the pollen. Bioinformatics tools allowed us to associate many of the induced genes with metabolic pathways that are probably upregulated during jasmonate‐induced maturation. Our pathway analysis led to the identification of specific genes within larger families of homologues that apparently encode stamen‐specific isozymes. Extensive additional analysis of our dataset identified 13 transcription factors that may be key regulators of the stamen maturation processes triggered by jasmonate. Two of these transcription factors, MYB21 and MYB24, are the only members of subgroup 19 of the R2R3 family of MYB proteins. A myb21 mutant obtained by reverse genetics exhibited shorter anther filaments, delayed anther dehiscence and greatly reduced male fertility. A myb24 mutant was phenotypically wild‐type, but production of a myb21myb24 double mutant indicated that introduction of the myb24 mutation exacerbated all three aspects of the myb21 phenotype. Exogenous jasmonate could not restore fertility to myb21 or myb21myb24 mutant plants. Together with the data from transcriptional profiling, these results indicate that MYB21 and MYB24 are induced by jasmonate and mediate important aspects of the jasmonate response during stamen development.
Novel micro‐RNAs and intermediates of micro‐RNA biogenesis from moss
Authors: Talmor‐Neiman Mali , Stav Ran , Frank Wolfgang , Voss Bjoern , Arazi Tzahi 
Published: May 2006

SummaryMicro‐RNAs (miRNAs) are one class of small non‐coding RNAs that have important regulatory roles in higher plants. Much less is known about their prevalence and function in lower land plants. Previously we cloned 100 non‐structural small RNAs from the moss Physcomitrella patens but could annotate only 11 as miRNAs. To identify additional moss miRNAs among cloned small RNAs we have analyzed their genomic sequences for a characteristic miRNA precursor‐like structure. This analysis revealed 19 new moss miRNAs that are predicted to be encoded by 22 putative foldbacks. Northern blot analysis confirmed the expression of 14 new miRNA representatives. Half of these were gametophore specific, the rest were detected at low levels in the protonema. We predicted 12 genes as targets of nine new miRNAs. Three of these show homology to transcription factors and the others appear to play roles in diverse physiological processes including light and cytokine signaling, which have not to date been shown to be regulated by a miRNA in flowering plants. Four target genes, which show homology to ATN1‐like protein kinase, NAC transcription factors and a cytokinin receptor, have been validated by miRNA‐mediated mRNA cleavage. In addition, our analysis revealed that seven small RNAs represent miRNA* and three represent intermediates of pre‐miRNA processing, providing evidence for specific DICER‐like cleavage steps during miRNA biogenesis in moss. Our findings suggest that miRNAs are common in mosses and set the stage for the elucidation of their varied biological functions.
Investigation of the p.Ser278Arg polymorphism of the autoimmune regulator (AIRE) gene in alopecia areata
Authors: Pforr J. , Blaumeiser B. , Becker T. , Freudenberg‐Hua Y. , Hanneken S. , Eigelshoven S. , Cuyt I. , De Weert J. , Lambert J. , Kruse R. , Nöthen M. M. , Betz R. C. 
Published: May 2006

AbstractA recent study has suggested that the g.961C>G (p.Ser278Arg) variant of the autoimmune regulator (AIRE) gene contributes to susceptibility to alopecia areata (AA). We attempted to replicate this finding using a case‐control sample of Belgian‐German origin (273 patients and 283 controls). Despite adequate power, our study results do not support a significant association of the risk allele in our AA patient sample. This remained the case when we stratified our sample according to severity and family history of disease. Our study results do not support the hypothesis that the g.961C>G (p.Ser278Arg) polymorphism of the AIRE gene is associated with an increased risk for AA.
The 32‐base pair deletion of the chemokine receptor 5 gene (CCR5‐Δ32) is not associated with primary sclerosing cholangitis in 363 Scandinavian patients
Authors: Melum E. , Karlsen T. H. , Broomé U. , Thorsby E. , Schrumpf E. , Boberg K. M. , Lie B. A. 
Published: May 2006

AbstractCCR5 is a chemokine receptor expressed on T‐cells and macrophages. A 32‐base pair deletion in the chemokine receptor 5 gene (CCR5‐Δ32) leads to a non‐functional receptor. Conflicting evidence exists whether this deletion is associated with primary sclerosing cholangitis (PSC). We genotyped the CCR5‐Δ32 variant in 363 PSC patients and 366 controls. No significant increase in the Δ32 allele frequency was detected in the PSC patients compared to controls (12.7% vs 10.7% OR = 1.22, 95% CI [0.88, 1.68], P = 0.23). Survival analysis did not reveal any significant effects from CCR5‐Δ32 genotypes on disease progression. Thus, in this study (power > 90%, given OR = 2, α = 0.05), we were unable to replicate previous findings and our results do not support an involvement of CCR5‐Δ32 in either PSC susceptibility or progression.
Conservation of leukocyte cell surface proteins: implications for the generation of monoclonal antibodies against newly identified leukocyte cell surface proteins
Authors: Zola H. , Mavrangelos C. , Millard D. J. , Nicholson I. C. 
Published: May 2006

AbstractThe availability of mouse monoclonal antibodies has been integral to the classification of human leukocyte cell surface proteins under the ‘Cluster of Differentiation’ or ‘CD’ nomenclature system. The sequencing of the human genome has identified many more proteins that have characteristics similar to the known leukocyte cell surface proteins, but which have not so far been identified using monoclonal antibodies. One factor that may have limited the generation of monoclonal antibodies to some of these proteins is the high level of sequence conservation between the mouse and human proteins, in particular in the extracellular regions that are recognized by most of the widely used antibodies. An alternative approach is to use a more distant species, such as chickens, for the generation of antibody reagents. Here we compare the extent of amino acid differences in the protein CD molecules expressed by human leukocytes and their mouse and chicken homologs. The analysis confirms that the human proteins are more similar to the mouse homologs than the chicken homologs. The results indicate that chicken antibodies have the potential to be used as an alternative to mouse reagents where human‐mouse sequence conservation is high.
Slc11a1 (formerly Nramp1) polymorphisms and susceptibility to post‐transplant lymphoproliferative disease following pediatric liver transplantation
Authors: Barshes N.R. , Lee T.R. , Goss J.A. , Goodpastor S.E. , Huls M.H. , Rooney C.M. , Karpen S.J. , Wyllie S. 
Published: May 2006

Abstract: Background. Polymorphisms of the solute carrier family 11 member 1 (Slc11a1) gene have previously been associated with susceptibility to infectious disease, anti‐tumor defenses, and autoimmune diseases. We postulated that polymorphisms of the gene may also be associated with susceptibility to post‐transplant lymphoproliferative disease (PTLD), a disease thought to be related to an impaired immune response to Epstein–Barr virus (EBV) in immunosuppressed patients.Methods. Whole blood samples were obtained from 45 pediatric patients who underwent liver transplantation. Polymerase chain reaction (PCR) was used to amplify a 3′ region of the gene that includes an exon 15 single‐nucleotide substitution (referred to as D543N) and a 4‐bp deletion polymorphism (referred to as 3′‐UTR). PCR products were digested using AvaII and FokI restriction enzymes for the D543N and 3′‐UTR polymorphisms, respectively. PTLD disease status and EBV virus serum titers of all patients were obtained from hospital records.Results. Six of the 45 pediatric transplant recipients developed PTLD. An association was found between 3′‐UTR polymorphisms of Slc11a1 and incidence of PTLD after liver transplantation (P=0.005). In addition, post‐transplant serum EBV titers were higher (P=0.009) for recipients with certain Slc11a1 polymorphisms. No association was found between the D543N polymorphism and incidence of PTLD.Conclusion. 3′‐UTR polymorphisms of the Slc11a1 gene appear to be associated with susceptibility to PTLD and the immune response to EBV in pediatric liver transplant recipients. Genotyping of pediatric patients undergoing liver transplantation may enable early identification of patients at high risk for developing high EBV titers and/or PTLD.
Improved discrimination of self‐incompatibility S‐RNase alleles in cherry and high throughput genotyping by automated sizing of first intron polymerase chain reaction products
Authors: Sonneveld T. , Robbins T. P. , Tobutt K. R. 
Published: May 2006

AbstractA novel polymerase chain reaction (PCR) approach to determine and confirm the self‐incompatibility (S) genotype of cherries is reported. The method involves PCR amplification with a new pair of consensus primers that immediately flank the first intron of cherry S‐RNases, one of which is fluorescently labelled. Fluorescent amplification products range from 234 to c. 460 bp and can be sized accurately on an automated sequencer. Thirteen S alleles reported in sweet cherry can be distinguished, except for S2 and S7, which have an amplification product of exactly the same size. S13, which is also amplified, gives a microsatellite‐like trace which shows minor intra‐allelic length variation. This method gives fast and accurate results and should be especially useful for medium/high‐throughput genotyping of wild and cultivated cherries.
Field trial of serially passaged isolates of BYDV‐PAV overcoming resistance derived from Thinopyrum intermedium in wheat
Authors: Chain F. , Riault G. , Jacquot E. , Trottet M. 
Published: May 2006

AbstractBarley yellow dwarf disease (BYDD) is one of the main viral diseases of small grain cereals. This disease, reported on numerous plant species of the Poaceae family, is caused by a complex of viral species including the species Barley yellow dwarf virus‐PAV (BYDV‐PAV, family Luteoviridae, genus Luteovirus), frequently found in western Europe. Resistance sources towards BYDD are scarce. Indeed, breeding‐resistant genotypes is a long and expensive process. Thus, estimating the durability of the resistance genes before the achievement of selection would be an asset for breeders. One isolate of BYDV‐PAV has been serially passaged on two hosts, ‘Zhong ZH’ and ‘TC14’, carrying a gene for partial resistance. The resulting viral population showed an increase of the speed of development of the infection in controlled conditions. In this study, these viral populations were evaluated in a 3‐year field trial, including a susceptible host, ‘Rendezvous’, and a host carrying the resistance gene of ‘TC14’ in a ‘Rendezvous’ background, to assess the effect of serial passages in field conditions. Results indicate that isolates issued from serial passages on hosts carrying a gene for partial resistance induced increased damage in field conditions when compared with the initial isolate. Yield losses are mainly due to a decrease of the number of kernels per square metre. The interest on using partial resistance gene to control BYDD is discussed.
New mutants of winter rapeseed (Brassica napus L.) with changed fatty acid composition
Authors: Spasibionek S. 
Published: May 2006

AbstractSeeds of the winter oilseed rape (Brassica napus L.) line PN 3756/93 were treated with ethyl methanesulphonate to induce mutations in the fatty acid biosynthetic pathway. The seed mutagenic treatment was repeated in the M2 generation. After treatments, individual seed and plant selections were made for changes in fatty acid composition during several generations of inbreeding. Self‐pollinated plants with changed fatty acid compositions were inbred to obtain genetically homozygous and stable mutant lines. Two mutants, M‐10453 and M‐10464, with increased levels of oleic acid (approximately 76%) and reduced linoleic and linolenic acid contents (8.5% and 7.5%, respectively) were selected. Gene or genes controlling desaturation of oleic acid were probably mutated in these plants. The third mutant, M‐681 had a very low linolenic acid content (approximately 2.6%) and increased linoleic acid content (approximately 26%). This would suggest the occurrence of mutations in genes controlling linoleic acid desaturation. The results of selection work during several generations showed that the environment had substantial influence on the composition of seed oil. This made the search for mutants with modify fatty acid compositions difficult. The induced mutants are not directly usable as new varieties, but can be used as parents in crosses for the development of high quality rapeseed varieties.
Inheritance of insensitivity to culture filtrate of Pyrenophora tritici‐repentis, race 2, in wheat (Triticum aestivum L.)
Authors: Singh P.K. , Hughes G.R. 
Published: May 2006

AbstractTan spot of wheat is caused by the fungus Pyrenophora tritici‐repentis. On susceptible hosts, P. tritici‐repentis induces two phenotypically distinct symptoms, tan necrosis and chlorosis. This fungus produces several toxins that induce tan necrosis and chlorosis symptoms in susceptible cultivars. The objectives of this study were to determine the inheritance of insensitivity to necrosis‐inducing culture filtrate of P. tritici‐repentis, race 2, and to establish the relationship between the host reaction to culture filtrate and spore inoculation with respect to the necrosis component. The F1, F2, and BC1F1 plants and F2:8 lines of five crosses involving resistant wheat genotypes ‘Erik’, ‘Red Chief’, and line 86ISMN 2137 with susceptible cultivars ‘Glenlea’ and ‘Kenyon’ were studied. Plants were spore‐inoculated at the two‐leaf stage. Four days later, the newly emerged uninoculated third leaf was infiltrated with a culture filtrate of isolate Ptr 92–164 (race 2). Reactions to the spore inoculation and the culture filtrate were recorded 8 days after spore inoculation. The segregation observed in the F2 and BC1F1 generations and the F2:8 lines of all crosses indicated that a single recessive gene controlled insensitivity to necrosis caused by culture filtrate. This gene also controlled resistance to necrosis induced by spore inoculation.
Nitrogen and phosphorus uptake and utilization efficiency in D(R) substitution lines of hexaploid triticale
Authors: Oracka T. , ŁApiński B. 
Published: May 2006

AbstractTwo sets of disomic substitution lines, derived from the cultivars ‘Presto’ and ‘Rhino’ of triticale, with rye chromosome pairs replaced by their wheat D‐genome homoeologues, were tested in hydroponic culture for nitrogen and phosphorus uptake and utilization efficiency. The effect of a substitution on the amount of absorbed nutrients was predominantly negative and proportional to the effect on plant dry matter. Significant decreases were found for the substitutions 5D(5R), 6D(6R) of both cultivars, 2D(2R), 4D(4R) of ‘Presto’ and 3D(3R) of ‘Rhino’. On the other hand, the nitrogen utilization efficiency was significantly increased in all substitution lines, with the exception of the 1D(1R) ones. The differences in phosphorus utilization were generally positive, but less pronounced, and significant only in the lines 2D(2R) and 6D(6R). The data suggest that presence of both rye and D‐genome chromosomes is conducive for the best effect of the applied N and P fertilizers.