bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation, identification and molecular characterization of physiological races of apple powdery mildew (Podosphaera leucotricha)
Authors: Urbanietz A. , Dunemann F. 
Published: March 2005

The development of apple varieties displaying durable resistance against powdery mildew is one of the major aims in apple breeding programmes worldwide. For a reliable judgment of the resistance of different Malus genotypes, an extended knowledge about the virulence of the pathogen is necessary. To prove the existence of physiological races of Podosphaera leucotricha, 31 monoconidial isolates of the obligate biotrophic fungus representing five locations within Europe have been established and maintained over a period of 3–4 years. The isolates were maintained on in vitro shoots of the highly susceptible apple cv. Gibb's Golden Gage. An AFLP‐based DNA fingerprinting protocol was developed and, using 54 stably reproducible AFLP markers, a dendrogram revealed genetic variability among different isolates of P. leucotricha. Although the molecular characterization of the isolates showed an overall low level of genetic variability, the high phenotypic diversity among European isolates suggest that sexual reproduction may also be involved in the disease cycle of the pathogen in Europe. Phytopathological tests using detached leaves of a collection of 36 Malus genotypes allowed the differentiation of five selected isolates by their virulence patterns. A high level of diversity in terms of virulence was obtained in P. leucotricha. From the present study, based on apple breeding germplasm, cultivars and Malus species, it can be concluded that physiological races of P. leucotricha do indeed exist in Europe.
Effect of temperature on head blight of wheat caused by Fusarium culmorum and F. graminearum
Authors: Brennan J. M. , Egan D. , Cooke B. M. , Doohan F. M. 
Published: March 2005

The effect of small temperature differentials (16 vs. 20°C) on the pathogenicity of deoxynivalenol producing single isolates of Fusarium culmorum and F. graminearum and on the fusarium head blight (FHB) response of eight wheat cultivars was examined. Fusarium culmorum inoculation caused greater visual disease symptoms at 20°C than at 16°C, both overall and on an individual cultivar basis (overall AUDPC = 13·5 and 9·6, respectively) (P < 0·05). In contrast, F. graminearum inoculation caused greater overall visual disease symptoms at 16°C than at 20°C, both overall and at the individual cultivar level (overall AUDPC = 12·8 and 10·9, respectively) (P < 0·05). Results showed both F. culmorum and F. graminearum inoculations caused a greater loss in yield at 20°C (54·3 and 46·9% relative 1000‐grain weight, respectively) compared with 16°C (73·3 and 66·9% relative 1000‐grain weight, respectively) (P < 0·05). Fusarium culmorum‐inoculated heads contained similar amounts of fungal DNA at both 16 and 20°C (1·9 and 1·7 ng mg−1 of plant material, respectively) (not significant), while for F. graminearum inoculation, plants contained higher amounts of fungal DNA at 20°C (2·0 and 1·0 ng mg−1 of plant material, respectively) (P < 0·05). Overall, there was a significant negative correlation between AUDPC and percentage relative 1000‐grain weight at both 16 and 20°C (r =−0·693 and −0·794, respectively, P < 0·01).
Double‐stranded RNA: distribution and analysis among isolates of Rhizoctonia solani AG‐2 to ‐13
Authors: Bharathan N. , Saso H. , Gudipati L. , Bharathan S. , Whited K. ,   K. Anthony
Published: March 2005

The occurrence, distribution, and genetic relatedness of double‐stranded RNA (dsRNA) components from 36 isolates of Rhizoctonia solani belonging to nine anastomosis groups (AGs) were studied using electrophoretic analysis and RNA–RNA blot hybridization. DsRNA was consistently detected in all 36 isolates. The size of the dsRNA components varied considerably, ranging from 0·74 to 23 kb. Two thirds of isolates possessed different size dsRNA components. Only two of the isolates had small size dsRNA between 0·5 and 1·0 kb. The biotin‐labelled dsRNA probes provided the sensitivity and specificity required to study genetic relationships of dsRNA. As little as 10 pg of ‘hybridizing’ dsRNA could be detected using biotin‐labelled total dsRNA with no detectable nonspecific‐hybridization. Results from several dot‐spot as well as RNA–RNA gel hybridization experiments revealed considerable sequence heterogeneity among dsRNA components within each isolate or isolates from the same AG.
Cultivar preference exhibited by two sympatric and genetically distinct populations of the soybean fungal pathogen Phialophora gregata f.sp. sojae
Authors: Meng X. , Grau C. R. , Chen W. 
Published: March 2005

Phialophora gregata f.sp. sojae, a soilborne vascular pathogen causing brown stem rot of soybean, has been divided into A and B populations based on variation in the intergenic spacer region of nuclear rDNA (rDNA marker). The A and B populations correlate with defoliating and nondefoliating pathotypes, respectively. In this study, eight additional polymorphic anonymous marker loci (five inter simple sequence repeat loci and three long‐primer random amplified polymorphic DNA loci) were identified and applied to a total of 189 isolates. Alleles of these eight loci were invariant within, but different between the A and B populations, providing further evidence that the rDNA marker identifies genetically distinct populations. The two populations were sympatric, residing not only in the same field, but also in the same plants under field conditions. Representative strains of the two populations, when used individually in inoculations, infected both resistant cv. Bell and susceptible cv. Sturdy. However, when the same representatives of the two populations were mixed in a 1 : 1 ratio and used as a mixed inoculum in a competitive bioassay, differential cultivar preference was revealed using PCR detection of populations in infected plants. Population A was detected significantly more often (18 out of 24 plants) in the susceptible cv. Sturdy, whereas population B was detected significantly more often (17 out of 24 plants) in the resistant cv. Bell, corroborating earlier field studies. This is the first controlled experiment to demonstrate a differential host preference of P. gregata f.sp. sojae toward different cultivars of the same host species. Unification of terminologies used in P. gregata f.sp. sojae is discussed.
Potential role for salicylic acid in induced resistance of asparagus roots to Fusarium oxysporum f.sp. asparagi
Authors: He C. Y. , Wolyn D. J. 
Published: March 2005

Pre‐inoculation of asparagus (Asparagus officinalis) roots with selected nonpathogenic isolates of Fusarium oxysporum (npFo) has previously been shown to induce systemic resistance against infection by F. oxysporum f.sp. asparagi (Foa) through activation of plant‐defence mechanisms. To elucidate the putative npFo‐mediated defence pathways, the effect of salicylic acid (SA) was examined in a split‐root system of asparagus where one half of the seedling root system was drenched with SA and the activation of defence responses was measured subsequently on the remaining roots. SA‐treated plants exhibited enhanced systemic resistance, with a significant reduction in disease severity of the roots inoculated with Foa, compared with untreated plants. SA activated peroxidase and phenylalanine ammonia‐lyase, as well as lignification, upon Foa attack, in a manner similar to that observed with npFo pretreatment. In addition, application of diphenyleneiodonium, an SA biosynthesis inhibitor, led to failure of npFo to induce lignin deposition and systemic resistance. Treatment of fungal spores with SA did not affect germination and growth of either npFo or Foa in in vitro antifungal assays. Production of SA at the site of npFo infection may be involved in the induction of Foa resistance in asparagus roots.
Presence of the Stb6 gene for resistance to septoria tritici blotch (Mycosphaerella graminicola) in cultivars used in wheat‐breeding programmes worldwide
Authors: Chartrain L. , Brading P. A. , Brown J. K. M. 
Published: March 2005

Fifty‐two wheat cultivars and breeding lines, most of which have been used in breeding programmes worldwide, were tested for isolate‐specific resistance to Mycosphaerella graminicola isolate IPO323, which interacts with the Stb6 gene of wheat (first identified in cvs Flame and Hereward) via a gene‐for‐gene relationship. Twenty‐three lines were specifically resistant to this isolate. Sixteen resistant lines were crossed with Flame for a test of allelism. All progeny lines were resistant, suggesting that the 16 parental lines had Stb6, a gene allelic to it or a gene closely linked to it. In 14 lines, resistance to IPO323 was controlled by Stb6 only. An exception was Kavkaz‐K4500 L6.A.4., which has two genes for resistance to IPO323, one of which is Stb6. The microsatellite marker Xgwm369 was used to examine genetic diversity in the region of the genome containing Stb6, to which it is closely linked. Eleven alleles of Xgwm369, with amplified fragments of 10 different sizes, as well as apparent nonamplification of this marker in Bulgaria 88, were detected. Through the use of information about lines’ ancestry, combined with Xgwm369 alleles, it was shown that Stb6 entered world wheat‐breeding programmes on a minimum of six occasions, and possibly from as many as 11 sources. The presence of Stb6 in both European and Chinese landraces suggests that this gene has been present in cultivated wheat since the earliest times of agriculture.
Development ofOculimacula yallundaeandO. acuformis(eyespot) on leaf sheaths of winter wheat in the UK in relation to thermal time
Authors: Wan A. M. , Bock C. H. , Fitt B. D. L. , Harvey J. L. , Jenkyn J. F. 
Published: March 2005

In a controlled environment (15/10°C) (day/night) container experiment on winter wheat (cv. Avalon), eyespot incidence (percentage of plants affected) and number of leaf sheaths penetrated after 6 weeks increased with inoculum concentration (102−106conidia mL−1) ofOculimacula yallundae(OY) orOculimacula acuformis(OA), but there was no difference between the two species. In an outdoor container experiment, seedlings inoculated with OY 2 weeks after sowing had a greater incidence of eyespot than those inoculated with OA, when assessed 7 weeks after inoculation. Seedlings inoculated with OA at 10 or 20 weeks after sowing developed more severe eyespot by maturity than those inoculated with OY. In an experiment at 15/10°C with seedlings inoculated with OY + OA 2 weeks after sowing, more leaf sheaths were penetrated by OY (3·0 per plant) than OA (2·3 per plant) 6 weeks after inoculation. Field experiments with winter wheat consistently showed leaf sheath production, leaf sheath death, and number of leaf sheaths infected or penetrated by OA or OY were related linearly to thermal time (°C days) after sowing. Depending on cultivar, season and sample, a new leaf sheath was produced in 116–216°C days; a leaf sheath died in 221–350°C days; and infection of a new leaf sheath occurred in 129–389°C days. The mean number of living leaf sheaths infected differed between samples, cultivars and seasons for both OY and OA. Regression analysis of the 1985/86 data suggested that OY progressed more rapidly than OA through the leaf sheaths, and that both the pathogens progressed more rapidly than the rate of leaf sheath death, but more slowly than the rate at which leaf sheaths were produced. It also suggested that OA progressed more slowly than the rate at which leaf sheaths died in 1987/88, but OY did not.
Evaluation of foliar resistance in potato to Phytophthora infestans based on an international field trial network
Authors: Hansen J. G. , Koppel M. , Valskyte A. , Turka I. , Kapsa J. 
Published: March 2005

During the period 2000–03, local potato cultivars in Estonia, Latvia, Lithuania, Poland and Denmark were tested for foliar resistance to Phytophthora infestans (late blight) in an international field trial network. Four standard cultivars were included in the trials: Sava, Oleva, Danva and Kuras. Primary disease‐assessment data were entered into a common database, and parameters from the disease progress curves were calculated and made available on interactive web pages. A regression model, using relative area under disease progress curve (RAUDPC) values for cv. Oleva as a reference, was developed for the estimation of 1–9 scale values, where 1 = most susceptible. Standard deviations for the estimated 1–9 scale values and a nonparametric rank stability analysis of RAUDPC were used to evaluate the stability of resistance of the cultivars. Overall, the results showed stability of resistance for cvs Sava, Oleva and Danva, but not for Kuras. Use of the Internet‐based Web‐Blight service in this study facilitated comparison of results among countries for the level and stability of resistance. The estimated 1–9 scale values were similar to, or slightly lower than, those from official cultivar lists or from the European Cultivated Potato Database, especially for the more resistant cultivars. Possible reasons for discrepancies from different sources and locations are discussed. It is concluded that RAUPDC and the derived 1–9 scale values are useful for ranking cultivars for resistance to P. infestans, but this information is not detailed enough for use in a decision support system for late blight control.
Meconium Aspiration Syndrome Induces Complement‐Associated Systemic Inflammatory Response in Newborn Piglets
Authors: Castellheim A. , Lindenskov P. H. H. , Pharo A. , Aamodt G. , Saugstad O. D. , Mollnes T. E. 
Published: March 2005

AbstractThe pathophysiology of meconium aspiration syndrome (MAS) is complex. We recently showed that meconium is a potent activator of complement. In the present study, we investigated whether the complement activation occurring in experimental MAS is associated with a systemic inflammatory response as judged by granulocyte activation and cytokine and chemokine release. MAS was induced by the instillation of meconium into the lungs of newborn piglets (n = 8). Control animals (n = 5) received saline under otherwise identical conditions. Haemodynamic and lung dynamic data were recorded. Complement activation, revealed by the terminal sC5b‐9 complex (TCC), and cytokines [interleukin (IL)‐6 and IL‐8] were measured in plasma samples by enzyme immunoassays. The expression of CD18, CD11b and oxidative burst in granulocytes was measured in whole blood by flow cytometry. Plasma TCC increased rapidly in the MAS animals in contrast with controls (P < 0.0005). The TCC concentration correlated closely with oxygenation index (r = 0.48, P < 0.0005) and ventilation index (r = 0.57, P < 0.0005) and inversely with lung compliance (r = −0.63, P < 0.0005). IL‐6 and IL‐8 increased in MAS animals compared with the controls (P = 0.002 and P < 0.001, respectively). Granulocyte oxidative burst declined significantly in the MAS animals compared with the controls (P < 0.02). TCC correlated significantly with IL‐6 (r = 0.64, P < 0.0005) and IL‐8 (r = 0.32; P = 0.03) and inversely with oxidative burst (r = −0.37; P = 0.02). A systemic inflammatory response associated with complement activation is seen in experimental MAS. This reaction may contribute to the pathogenesis of MAS.
Increased Frequency of C4B*Q0 Alleles in Patients with Henoch–Schönlein Purpura
Authors: Stefansson Thors V. , Kolka R. , Sigurdardottir S. L. , Edvardsson V. O. , Arason G. , Haraldsson A. 
Published: March 2005

AbstractHenoch–Schönlein purpura (HSP) is a vasculitis of unknown aetiology, possibly involving immune complexes. The complement system is essential for the clearance of immune complexes. Our aim was to explore the hypothesis that patients with HSP have abnormal complements, contributing to the development of the disease. The study included 56 patients diagnosed with HSP at the Children's Hospital, Iceland between 1984 and 2000, and 98 blood donors as controls. Serum levels of immunoglobulin A, C4A, C4B and mannan‐binding lectin were measured and compared between the two groups. C4 null alleles were significantly more common in HSP patients than in controls (P = 0.018) and were carried by 66.1% of the patients compared with 41.2% of the controls. This difference was due to an increased frequency of C4B*Q0 allele in the HSP group (0.25 versus 0.11 in the control group; P = 0.002). The fact that the majority of our patients carried a C4 null allele indicates that children with C4 deficiencies may have an increased risk of developing HSP. This may reflect inadequate complement activity and possibly present an opportunity to identify patients at risk of developing serious morbidity associated with HSP.
The Inhibitory Effect of Altered Collagen II Peptide on HLA‐DRB1‐Restricted T‐Cell Activation
Authors: Cheng Y. J. , Zhou Q. , Li Z. G. 
Published: March 2005

AbstractIt has been known that rheumatoid arthritis (RA)‐associated antigenic peptides CII263–272 are coupled with human leucocyte antigen (HLA)‐DRB1 and recognized by T‐cell receptor (TCR), which in turn induced T‐cell proliferation and pathogenesis of RA. Non‐T‐cell‐stimulating type II collagen (CII) peptides might be generated by removing the amino acids responsible for TCR contact and keeping the HLA‐DR‐binding residues intact. In this study, a panel of altered CII peptides (APs) with consecutive or single substitutions of the TCR‐contacting residues were synthesized. Through peptide binding and T‐cell activation assays, we demonstrated that altered CII263–272 peptides with substitution of the TCR‐contacting residues did not or barely induced T‐cell activation; one of the best non‐T‐cell‐stimulating peptide AP268–270 inhibited the binding of wild‐type CII263–272 to HLA‐DR1 and T‐cell activation triggered by wild‐type CII263–272 and HA306–318 in a dose–response manner. These data suggest that removal of the TCR‐contacting residues of CII263–272 leads to HLA‐DRB1 binding and low T‐cell‐stimulating peptides, which could potentially inhibit the T‐cell response induced by HLA‐DRB1‐binding antigenic peptides.
Mycobacterium avium ssp. paratuberculosis Recombinant Heat Shock Protein 70 Interaction with Different Bovine Antigen‐Presenting Cells
Authors: Langelaar M. F. M. , Hope J. C. , Rutten V. P. M. G. , Noordhuizen J. P. T. M. , Van Eden W. , Koets A. P. 
Published: March 2005

AbstractHeat shock proteins (Hsp) can deliver antigen into the major histocompatibility complex class I presentation pathway of antigen‐presenting cells (APC), a process called cross priming, thus stimulating antigen‐specific CD8+ T‐cell reactions. Hsp were shown to elicit proinflammatory responses in APC. Both processes require interaction of Hsp with APC via specific receptors. This study describes the interaction of recombinant Hsp70 (rHsp70) of Mycobacterium avium subspecies paratuberculosis with bovine peripheral blood mononuclear cells that was restricted to CD14+ cells. Characterized monocyte‐derived macrophages, monocyte‐derived dendritic cells (DC) and BoMac, an immortalized bovine macrophage cell line, were used to investigate the interaction of rHsp70 with different bovine APC. Saturation of immature DC with high concentrations of rHsp70 is demonstrated, and it was found that interaction of rHsp70 with DC was related to the maturation stage of the DC. Involvement of CD91 as a cellular receptor for rHsp70 was demonstrated; however, competition studies with immature DC demonstrated that other receptors exist on bovine APC. These data suggest that rHsp70‐based vaccines may be useful for the successful immunization of cattle.
Inhibition by Artocarpus tonkinensis of the Development of Collagen‐Induced Arthritis in Rats
Authors: Ngoc D. D. T. , Catrina A. I. , Lundberg K. , Harris H. E. , Ha N. T. , Anh P. T. , Larsson P. 
Published: March 2005

AbstractExtracts of the leaves and roots from the tree Artocarpus tonkinensis A Cheval (family Moraceae) are used in traditional Vietnamese medicine in order to treat backache as well as rheumatic joint diseases. We prepared an ethyl acetate (EtOAc) extract from this plant and tested its anti‐inflammatory properties in an experimental arthritis model, collagen‐induced arthritis (CIA). CIA was induced in Dark Agouti rats by means of immunization with collagen type II (CII) emulsified in incomplete Freund's adjuvant. Starting at the day of immunization, the rats were treated daily with intraperitoneal injections of Artocarpus extract. Arthritis progression was measured by means of clinical scoring of paws and anti‐CII antibody titres were measured by means of ELISA. In vitro, lymph node (LN) cell cultures were treated with Artocarpus extract and the apoptosis‐inducing effect was determined with FACS staining by using annexin V and propidium iodide as well as the TUNEL method. Treatment of the rats with Artocarpus extract decreased arthritis incidence and severity and delayed disease onset. When treatment was started after the onset of arthritis, a tendency towards arthritis amelioration was observed. In vitro, Artocarpus extract acted as a T‐cell modulator, inhibiting mitogen‐induced T‐cell proliferation and inducing apoptosis of activated LN‐derived lymphocytes. Thus, we have demonstrated that an EtOAc extract of Artocarpus, a plant traditionally used in Vietnamese folk medicine for treating arthritic conditions, has beneficial effects in an experimental arthritis model. This effect is likely to be T cell‐dependent and mediated through apoptosis induction in activated cells.
T‐Cell Receptor Vβ Repertoire after Myeloablative and Reduced Intensity Conditioning Allogeneic Haematopoietic Stem Cell Transplantation
Authors: Hentschke P. , Omazic B. , Mattsson J. , Näsman‐Björk I. , Lundkvist I. , Gigliotti D. , Barkholt L. , Ringdén O. , Remberger M. 
Published: March 2005

AbstractT cells play an important role in the adaptive immune system. After haematopoietic stem cell transplantation (HSCT), T‐cell function is impaired. This is reflected by the emergence of opportunistic infections, infections that are often difficult to treat because of the patient's insufficient immune function. T‐cell receptor reconstitution was studied using CDR3 spectratyping to analyze the diversity of the T‐cell repertoire at 3, 6 and 12 months after myeloablative and reduced intensity conditioning (RIC) HSCT in 23 patients. Immune function in vitro was tested by lymphocyte stimulation at 3, 6 and 12 months after HSCT. Lower diversity in the CDR3 repertoire was demonstrated in CD4+ cells after RIC HSCT at 3 and 6 months and in CD8+ cells at 3 months compared with healthy donors. After myeloablative HSCT, lower diversity was seen at 3, 6 and 12 months in CD4+ cells and at 6 and 12 months in CD8+ cells after HSCT. Acute and chronic graft‐versus‐host‐disease (GVHD) did not affect diversity. Responses to phytohaemagglutinin (PHA), Concanavalin A (Con A) and Staphylococcus aureus protein A were significantly lower compared with healthy donors during the first 6 months after RIC HSCT. After myeloablative HSCT, lymphocyte response to Con A was significantly lower at 3 months compared with healthy donors. Decreased responses to cytomegalovirus and varicella zoster virus antigens were seen in patients suffering from acute GVHD grade II or chronic GVHD. The T‐cell repertoire is skewed under the first year after HSCT, and immune reconstitution after HSCT with myeloablative and RIC conditioning seems to be comparable. GVHD, infections and age are more important for immune reconstitution than type of conditioning.