bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integration host factor is involved in transcriptional regulation of theBrucella abortus virBoperon
Authors: Sieira Rodrigo , Comerci Diego J. , Pietrasanta Lía I. , Ugalde Rodolfo A. 
Published: October 2004

SummaryType IV secretion systems (T4SSs) are multicomponent machineries that play an essential role in pathogenicity of many facultative intracellular bacteria. ThevirBoperon ofBrucella abortuscodes for a T4SS essential for virulence and intracellular multiplication. Here, virB expression analyses carried out usinglacZtranscriptional fusions showed thatvirBpromoter (PvirB) is temporally activated within J774 cells. Primer extension experiments revealed that virB transcription starts at 27 bp upstream of the first gene of thevirBoperon. Structural analyses showed that PvirBand regulatory sequences involved in intracellular regulation span 430 bp upstream of the transcription start site. A protein able to bind PvirBwas isolated and identified.  This  protein,  homologue  to  integration host factor (IHF), specifically interacts with PvirBand induces a DNA bending with an angle of 50.36°. DNAse I footprinting experiments showed that IHF protects a 51 bp region that contains two overlapped IHF binding consensus motifs. VirB expression experiments carried out with PvirB‐lacZfusions showed that inB. abortusIHF participates in the regulation of PvirBactivity during the intracellular and vegetative growth in different media. A mutant strain with a 20 bp IHF binding site replacement failed to turn on thevirBoperon during the initial stages of macrophage infection and displayed severe intracellular multiplication defects. These data indicate that IHF plays a key role during intracellularvirBoperon expression being required for the biogenesis of the endoplasmic reticulum‐derived replicative vacuole.
Origin pairing (‘handcuffing’) and unpairing in the control of P1 plasmid replication
Authors: Das Nilangshu , Chattoraj Dhruba K. 
Published: October 2004

SummaryThe P1 plasmid origin has an array of five binding sites (iterons) for the plasmid‐encoded initiator protein RepA. Saturation of these sites is required for initiation. Iterons can also pair via their bound RepAs. The reaction, called handcuffing, is believed to be the key to control initiation negatively. Here we have determined some of the mechanistic details of the reaction. We show that handcuffed RepA–iteron complexes dissociate when they are diluted or challenged with cold competitor iterons, suggesting spontaneous reversibility of the handcuffing reaction. The complex formation increases with increased RepA binding, but decreases upon saturation of binding. Complex formation also decreases in the presence of molecular chaperones (DnaK and DnaJ) that convert RepA dimers to monomers. This indicates that dimers participate in handcuffing, and that chaperones are involved in reversing handcuffing. They could play a direct role by reducing dimers and an indirect role by increasing monomers that would compete out the weaker binding dimers from the origin. We propose that an increased monomer to dimer ratio is the key to reverse handcuffing.
Molecular approaches to malaria
Authors: Lingelbach Klaus , Kirk Kiaran , Rogerson Stephen , Langhorne Jean , Carucci Daniel J. , Waters Andrew 
Published: October 2004

SummaryMalaria is a serious health problem in developing countries. With the complete sequencing of the genomes of the parasite and of the mosquito vector, malaria research has entered the post‐genome era. In this report we summarize the results and new research avenues presented at a recent meeting held with the aim of developing interdisciplinary approaches to combat this disease.
Transmission of Streptococcus mutans in a group of Turkish families
Authors: Ersin N. K. , Kocabas E. H. , Alpoz A. R. , Uzel A. 
Published: October 2004

Background/aims:  To investigate the transmission of Streptococcus mutans in a group of Turkish families using AP‐polymerase chain reaction (PCR) detection.Methods:  Eight mothers who had high S. mutans levels in unstimulated saliva and 8 children aged between 2 and 3 years participated in the study. Plaque samples from each child were collected with the tips of sterile toothpicks for S. mutans counts. Although not part of the original study design, S. mutans samples were also obtained from the unstimulated saliva of the three fathers who shared the same households. Three typical isolates of S. mutans were isolated from TYCSB agar of each subject and identified by sugar fermentation tests. S. mutans ATCC 10449 was used as the reference strain. AP‐PCR was conducted with OPA‐05 primer.Results:  All of the mothers and fathers shared the similar genotypes within their children. The fathers also harbored similar genotypes to their spouses.Conclusion:  The mothers or the fathers could be the source for the transmission of S. mutans to their children.
Effect of Fruiting Traits on the Field Resistance of Cocoa (Theobroma cacao L.) Clones to Phytophthora megakarya
Authors: Efombagn M. I. B. , Marelli J. P. , Ducamp M. , Cilas C. , Nyassé S. , Vefonge D. 
Published: October 2004

AbstractThe effects of some traits of field resistance (precocity and duration of the fruiting cycle, age of diseased fruit and vertical pod distribution on the tree) to Phytophthora megakarya of four known cocoa clones were studied in an on‐station clonal plot planted in 1982 in the south‐west of Cameroon. Weekly observations of fruit set and development, black pod and rainfall were carried out during three growing seasons (1999, 2000 and 2001). The study confirmed the previous field and laboratory assessments of resistance of these clones based on the mean percentages of rotten pods obtained annually. The present study has permitted the identification of fruit aged 2–3 months as the highly susceptible stage of development in the most susceptible clone. In addition, precocity and pod cycle duration varied significantly among the clones. The earlier the pod cycle began, the more susceptible was the clone: the most resistant clone started flowering 1 month after the most susceptible clone and therefore escaped the peak of disease severity. Rainfall intensity greatly modified the incidence of the disease in 2001, with high yield losses occurring in all four clones (70–93%), but their ranking remained stable over the 3 years. The spatial distribution of pods on the trees showed that pods on the trunk were more likely to become diseased than those on the branches, but its effect as a clone resistance component is variable among the four clones; the resistant clone producing more pods on the trunk and the susceptible clone more in the canopy.
Virulence–Toxin Production Relationship in Isolates of the Plant Pathogenic Fungus Botrytis cinerea
Authors: Reino J. L. , Hernández‐Galán R. , Durán‐Patrón R. , Collado I. G. 
Published: October 2004

AbstractEleven isolates of Botrytis cinerea were studied to examine the relationship between toxin production and virulence. After 5 days of incubation, screening experiments revealed significant differences in toxin production by the strains. The isolates with low toxin production were less virulent; moreover, the only toxins isolated were those corresponding to botrydial or its derivatives. In contrast, higher amounts of toxins were isolated from the more aggressive isolates. Furthermore, two classes of toxins, those with botryane skeleton and botcinolide derivatives, were detected in and isolated from all aggressive strains studied. This indicates that a synergistic action of several toxins is involved in the phytotoxicity of this phytopathogen.
Agronomic and chemical characterization of 39 Hypericum perforatum accessions between 1998 and 2000
Authors: Poutaraud A. , Girardin P. 
Published: October 2004

AbstractThirty‐nine accessions of St John's Wort were studied over a 3‐year period. The percentage of diseased plants ranged from 0 to 100%. After 3 years of cultivation, 18% of the accessions presented a dieback rate of <10%. Hypericins and hyperforins in flowering tops (top 30 cm of plants at full bloom) and flowers were assayed using high‐performance liquid chromatography (HPLC‐DAD Diode Array Detector) (one to three cuttings a year). The hypericin contents in flowering tops ranged from 0.7 to 3%. These levels were, on average, 2.8‐fold lower than those recorded in flowers. Hyperforin levels varied in the different accessions, ranging from 0.65 to 3% in flowering tops and 2 to 5.7% in the flowers. In line with present industrial needs, a minimum content of one or more of the active components, it will therefore be necessary to select accessions in terms of the dry weight yield and the contents of flowering tops and flowers. Dry weight depends on cutting height, which also affects the quality of the plant material harvested. Because of the plant to plant variability, the performance of the accessions selected would be improved.
Tournefortii male sterility system in Brassica napus. Identification, expression and genetic characterization of male fertility restorers
Authors: Pahwa R. S. , Banga S. K. , Gogna K. P. S. , Banga S. S. 
Published: October 2004

AbstractA germplasm collection of 152 diverse rapeseed accessions from Canada, China, France, India, Poland and South Korea was assayed for identifying new fertility restorers and sterility maintainers for a Tournefortii (tour) cytoplasmic male sterility (CMS) system in rape‐seed. Only 16 (10.5%) genotypes showed complete fertility restoration following hybridization with tour CMS line NE 409A. Notable among these were GSL 8851, GSL 8953, Mokpo # 9, Mali, Buk‐wuk‐13, Kuju‐27 and Mokpo # 84. As many as 78 (51.3%) genotypes were perfect maintainers of sterility, the remaining 58 (38.2%) genotypes were classified as partial maintainers. To study the inheritance of fertility restoration, 20 CMS (tour) rapeseed lines were crossed with the four best fertility restorers, namely GSL 8851, GSL 8953, Kuju‐27 and Mokpo # 9, to obtain F2 and test cross populations. Segregation data indicated that fertility restoration for tour CMS was governed by two genes, of which, one is stronger than the other (χ212:3:1). Differences in gene interactions were also observed (χ29:3:4) which could be explained on the basis of influence of female parent genotypes/or modified expression of the restorer gene(s) in different genetic backgrounds. Tests of allelism indicated that the restorer genes present in the four restorers evaluated were allelic.
SCAR marker tagged to the alien leaf rust resistance gene Lr19 uniquely marking the Agropyron elongatum‐derived gene Lr24 in wheat: a revision
Authors: Prabhu K.V. , Gupta S. K. , Charpe A. , Koul S. 
Published: October 2004

AbstractA sequence characterized amplified region (SCAR) marker tagged to an Agropyron elongatum‐derived leaf rust resistance (Lr) gene Lr19 was validated on 18 known alien Lr gener in near‐isogenic lines (NILs) in the variety ‘Thatcher’, along with three wheat cultivers carrying Lr24 and two carrying Lr19. The marker was expressed only in the Lr24 lines confirming that the marker tagged the geneLr24. The monomorphic expression of the SCAR marker in 10NIL pairs for Lr19 and Lr24 revealed that each NIL pair possessed the same gene, Lr24. The donor parents used in the NIL pairs for Lr19 (‘Sunstar*6/C80‐1′) and Lr24 (‘TR380‐14*7/3Ag#14′) amplified the same fragment. Nonsegregation for leaf rust in the F2 population of the cross between the above donor parents confirmed the presence of the same gene in the two parents. Apparently, a genuine parent stock of ‘Sunstar*6/C80‐1’ was not involved in the development of the NIL pairs for Lr19 due to an improper maintence bredding protocol either at source or destination which went undetected in the absence of signs of virulence for either gene in the region.
Diallel analysis of callus formation ability in linseed anther culture
Authors: Lassaga S. L. , Camadro E. L. , Bonell M. L. , Franzone P. 
Published: October 2004

AbstractIn linseed, the time needed to obtain pure lines can be reduced by using in vitro anther culture. The technique has been improved but there are no reports on the inheritance of the characters (callogenesis and regeneration) involved in the response. To shed some light on this aspect, anthers of four linseed varieties and their F1 were cultivated in vitro. Callogenesis response was analysed according to a full diallel model. Among 7811 anthers, the percentage of callogenesis ranged from 27.40 to 82.04%, with the parental lines being around the average. The differences between specific hybrid combinations were significant and general and specific combining ability were highly significant. As well as dominant effects, additive and non‐additive effects are probable components of the heritability of this character, although additive effects would be more important than non‐additive. Differences between reciprocal crosses would indicate that cytoplasmic factors could also be involved in the determination of the character.
Genetic analysis of petal size through genomic manipulation in Brassica
Authors: Lu C. M. , Zhang B. , Liu L. , Kato M. 
Published: October 2004

AbstractThe effect of genome composition and cytoplasm on petal size was studied in Brassica. Two accessions of Brassica rapa (2n = 20, AA) were reciprocally crossed with three accessions of Brassica oleracea (2n =18, CC) to produce resynthesized B. napus (2n = 38, AACC or CCAA) and sesquidiploids (2n = 29, AAC or CAA). Petal size was measured and compared among diploids (AA and CC), sesquidiploids (AAC and CAA) and amphidiploids(AACC and CCAA). The results showed that petal size is a genome‐dependent and highly heritable character. The heritability of petal length is as high as 96.3%. The addition of each C‐genome to the AA genomic background increased the petal length by 4‐5 mm. Cytoplasm of B. oleracea showed a positive effect on petal length by about 1.3 mm over that of B. rapa. Petal width was positively correlated with petal length at a highly significant level (r= 0.806, df = 81). Resynthesized B. napus (AACC) showed significantly larger flower petals than natural rapeseed cultivars (AACC).
Detection of molecular markers linked to the durable adult plant stripe rust resistance gene Yr18 in bread wheat (Triticum aestivum L.)
Authors: Imtiaz M. , Ahmad M. , Cromey M. G. , Griffin W. B. , Hampton J. G. 
Published: October 2004

AbstractStripe rust of wheat caused by Puccinia striiformis West. f. sp. tritici presents a serious problem for wheat production worldwide, and identification and deployment of resistance sources to it are key objectives for many wheat breeders. Here we report the detection of simple sequence repeat (SSR) markers linked to the durable adult plant resistance of cv. ‘Otane’, which has conferred this resistance since its release in New Zealand in 1984. A double haploid population from a cross between ‘Otane’ and the susceptible cv. Tiritea’ was visually assessed for adult plant infection types (IT) in the glasshouse and field, and for final disease severity in the field against stripe rust pathotype 106E139A+. At least three resistance loci controlled adult plant resistance to stripe rust in this population. Quantitative trait loci (QTL) mapping results revealed that two of these, one on chromosome 7DS corresponds to the durable adult plant resistance gene Yr18 and other on chromosome 5DL were contributed from ‘Otane’; while the remaining one on chromosome 7BL, was contributed from the susceptible ‘Tiritea’. Interval mapping placed the ‘Otane’‐resistant segment near the centromere of chromosome 7DS at a distance of 7 cM from the SSR marker gwm44. The stability of QTL in the two environments is discussed. SSR gwm44 is potentially a candidate marker for identifying the durable resistance gene Yr18 in breeding programmes.
Relationship between heterosis and genetic distance based on morphological traits and AFLP markers in pepper
Authors: Geleta L. F. , Labuschagne M. T. , Viljoen C. D. 
Published: October 2004

AbstractGenetic diversity is considered as one of the criteria for the selection of parents for hybrid breeding. The present study was undertaken to evaluate genetic divergence among seven pepper cultivars and to assess the relationship between heterosis and parental genetic distance. Twenty‐one F1 hybrids and seven parents were evaluated for 15 morphological characters in a greenhouse and in the field. The parents were examined for DNA polymorphisms using six amplified fragment length polymorphism (AFLP) primer combinations. Cluster analysis using two genetic distance measures grouped the seven parents differently. Mid‐parent and high‐parent heterosis was observed for most characters. Most hybrids outperformed the parental lines for fruit yield, earliness and plant height. Morphological and AFLP‐based distance measurements were efficient enough to allocate pepper genotypes into heterotic groups. The correlations of morphological distances with mid‐parent heterosis were significant for days to flowering and maturity, suggesting earliness can be predicted from morphological distances of parental lines. However, the correlations of AFLP‐measured genetic distances with mid‐ and high‐parent heterosis were non‐significant for all characters, except for fruit diameter, and proved to be of no predictive value.
Quantitative trait loci for leafhopper (Empoasca fabae and Empoasca kraemeri) resistance and seed weight in the common bean
Authors: Murray J. D. , Michaels T. E. , Cardona C. , Schaafsma A. W. , Pauls K. P. 
Published: October 2004

AbstractA population of 108 common bean recombinant inbred lines (RILs) (F5:6‐9), derived from a leafhopper (Empoasca fabae and E. kraemeri)‐susceptible cultivar (‘Berna’) and a leafhopper‐resistant line (EMP 419) was used to identify molecular markers genetically linked to leafhopper resistance and seed weight. Bulked segregant analysis and quantitative trait analysis identified eight markers that were associated with resistance to E. fabae, and four markers that were associated with E. kraemeri resistance. Three markers were associated with resistance to both species. A partial linkage map of the bean genome was constructed. Composite interval mapping identified quantitative trait loci (QTL) for resistance to both leaf hopper species on core‐map linkage groups B1, B3 and B7. QTL for seed weight were found close to the locus controlling testa colour and an α‐phaseolin gene.
Monosomic analysis of Helminthosporium leaf blight resistance genes in wheat
Authors: Ragiba M. , Prabhu K. V. , Singh R. B. 
Published: October 2004

AbstractA set of 21 monosomic (2n ‐ 1) and the disomic (2n) lines of the ‘Chinese Spring’ cultivar were crossed with ‘Chirya‐3′, the CIMMYT synthetic wheat line which has been identified as highly resistant for Helminthosporium leaf blight disease (HLB), in order to locate the genes governing disease resistance. The F1 and segregating populations were challenged and screened against the most virulent pure mono‐conidial HLB isolate KL‐8 (Karnal, India). The F1 progenies of the crosses were found to be susceptible because of the recessive nature of resistance. The F2 progeny of the control cross (‘Chinese Spring’×‘Chirya‐3’), segregated in the ratio of 1: 15 (resistant: susceptible), indicating that resistance to HLB was controlled by a pair of recessive genes. While the F2 progeny of 19 monosomic crosses segregated in the ratio of 1: 15 (resistant: susceptible), the progeny of the remaining two crosses, 7B and 7D, deviated significantly from the ratio, revealing that 7B and 7D were the critical chromosomes for resistance genes that were located one on each chromosome. Moreover, the critical lines, 7B and 7D, confirmed the digenic complementary recessive nature of gene action by fitting well with the overall pooled F2 segregation ratio of 13: 51 (resistant: susceptible) as expected for digenic complementary recessive resistance. The F3 segregation ratios of the critical crosses, based on their pooled F2 analysis, was estimated as 19: 32: 13 (non‐segregating susceptible: segregating as susceptible and resistant: non‐segregating resistant). F3 progenies when tested with these ratios showed goodness‐of‐fit, confirming that the two pairs of recessive resistance genes were located on chromosomes 7B and 7D.
A dominant gdcP‐specific marker derived from Moricandia nitens used for introducing the C3‐C4 character from M. nitens into Brassica crops
Authors: Zhang C. , Xu G. , Huang R. , Chen C. , Meng J. 
Published: October 2004

AbstractDifferential localization of decarboxylation and carboxylation in association with Kranz anatomy distinguish species with C4 or C3‐C4 intermediate photosynthesis from species with C3 photosynthesis. Moricandia nitens has a C3‐C4 intermediate photosynthetic mechanism and yet is closely related to C3Brassica species. In order to introduce the C3‐C4 character from M. nitens into Brassica crops, sesquitetraploids (MACC) were synthesized by crossing Brassica napus (AACC) and a somatic hybrid (M. nitens+B. oleracea, MMCC). Homologous fragments (2966 and 3254 bp) of P‐protein gene of glycine decarboxylase (gdcP) were isolated from M. nitens and B. napus, respectively, to develop a PCR‐based marker for assisted selection. Reverse transcriptase‐polymerase chain reaction (RT‐PCR) of the partial encoding regions of both gdcPs indicated that the mRNAs were expressed in the expanded leaf. The characterization of high divergence, but with large conserved island in the regulatory region of the two C3 species, implies that they may play an important role in maintaining the C3 photosynthetic pathway. Thereafter, a dominant gene‐specific marker was developed within the highly divergent region for subsequent introduction of C3‐C4 photosynthesis from Moricandia nitens into Brassica crops.
Immunohistochemical study of apparently intact coronary artery in a child after Kawasaki disease
Authors: Suzuki Atsuko , Miyagawa‐Tomita Sachiko , Komatsu Keiko , Nakazawa Makoto , Fukaya Takashi , Baba Kunizou , Yutani Chikao 
Published: October 2004

Abstract
Background
: Coronary arterial lesions (CAL) due to Kawasaki disease (KD) often show progressive intimal hyperplasia even many years after the disease. However, most patients have no CAL after the acute phase, and it is an important issue whether or not coronary arteries without CAL have significant intimal hyperplasia, and whether or not there is the potential for this to progress to stenosis and/or atherosclerosis.
Methods
: The authors examined formalin‐fixed specimens of the coronary arteries immunohistochemically, using antibodies against vascular growth factors (GFs), the receptors of transforming growth factor‐β (TβRs) and inducible nitric oxid synthesis (iNOS) in a KD patient without CAL, and also in four control patients: two with CAL due to KD and two without a history of KD.
Results
: Vascular endothelial GFs, Platelet‐derived growth factor‐A (PDGF‐A) and TβRs were expressed in the vascular smooth muscle cells of all patients. PDGF‐A, transforming Gfβ1 and iNOS were expressed in the intimal smooth muscle cells of the KD but not the normal coronary artery without a history of KD. The number of TβR‐II‐positive cells were fewer than TβR‐I‐positive cells in the intima of CAL due to KD, but the number was of both almost same in the intima of coronary artery without CAL after KD and in the normal coronary.
Conclusion
: The intact coronary artery 13 months after KD still showed the influence of the inflammation of KD. Although the authors speculate that the intimal proliferation will not continue beyond the acute phase, those patients may have a risk factor for atherosclerosis.