bluuebunny/crossref_metadata_2025 huggingface dataset:
The ColR–ColS two‐component signal transduction system is involved in regulation of Tn4652 transposition in Pseudomonas putida under starvation conditions
Authors: Hõrak Rita , Ilves Heili , Pruunsild Priit , Kuljus Martin , Kivisaar Maia
Published: October 2004

Bacteria use two‐component signal transduction pathways to sense both extracellular and intracellular environment and to coordinate cellular events according to changing conditions. Adaptation can be either physiological or genetical. Here, we present evidence that a genome reorganization process such as transposition can be controlled by certain environmental cues  sensed  by  a  two‐component  signal  transduction system. We demonstrate that transposition‐dependent accumulation of phenol‐utilizing mutants is severely decreased in Pseudomonas putida defective in a two‐component system colRS. Translocation of Tn4652 is decreased both in colR‐ and colS‐defective strains, indicating that signal transduction from a histidine kinase ColS to a response regulator ColR is necessary for the activation of Tn4652 in bacteria starving on phenol. However, overexpression of ColR in a colS‐defective strain restores Tn4652 transposition, suggesting that absence of the signal from ColS can be compensated by an elevated amount of ColR. In vitro analysis of purified ColR and ColS proteins evidenced that they constitute a functional phosphorelay. Site‐directed mutagenesis revealed that a conserved H221 can be the phosphoryl‐accepting residue in ColS and that aspartate residues D8 and D51 of ColR are necessary for the phosphotransfer from ColS to ColR. To our knowledge, Tn4652 is the first bacterial transposon regulated by a two‐component system. This finding indicates that transpositional activity can respond to signals sensed and processed by the host.
Export of Plasmodium falciparum calcium‐dependent protein kinase 1 to the parasitophorous vacuole is dependent on three N‐terminal membrane anchor motifs
Authors: Möskes Christian , Burghaus Petra A. , Wernli Barbara , Sauder Ursula , Dürrenberger Markus , Kappes Barbara
Published: October 2004

Calcium‐dependent protein kinases play a pivotal role in calcium signalling in plants and some protozoa, including the malaria parasites. They are found in various subcellular locations, suggesting an involvement in multiple signal transduction pathways. Recently, Plasmodium falciparum calcium‐dependent protein kinase 1 (PfCDPK1) has been found in the membrane and organelle fraction of the parasite. The kinase contains three motifs for membrane binding at its N‐terminus, a consensus sequence for myristoylation, a putative palmitoylation site and a basic motif. Endogenous PfCDPK1 and the in vitro translated kinase were both shown to be myristoylated. The supposed membrane attachment function of the basic cluster was experimentally verified and shown to participate together with N‐myristoylation in membrane anchoring of the kinase. Using immunogold electron microscopy, the protein was detected in the parasitophorous vacuole and the tubovesicular system of the parasite. Mutagenesis of the predicted acylated residues and the basic motif confirmed that dual acylation and the basic cluster are required for correct targeting of Aequorea victoria green fluorescent protein to the parasitophorous vacuole, suggesting that PfCDPK1 as the leishmanial hydrophilic acylated surface protein B is a representative of a novel class of proteins whose export is dependent on a ‘non‐classical’ pathway involving N‐myristoylation/palmitoylation.
The response regulator SsrB activates transcription and binds to a region overlapping OmpR binding sites at Salmonella pathogenicity island 2
Authors: Feng Xiuhong , Walthers Don , Oropeza Ricardo , Kenney Linda J.
Published: October 2004

OmpR activates expression of the two‐component regulatory system located on Salmonella pathogenicity island 2 (SPI‐2) that controls the expression of a type III secretion system, as well as many other genes required for systemic infection in mice. Measurements of SsrA and SsrB protein levels under different growth conditions indicate that expression of these two components is uncoupled, i.e. SsrB is produced in the absence of ssrA and vice versa. This result was suggested from our previous studies, in which two promoters at ssrA/B were identified. The isolated C‐terminus of SsrB binds to DNA and protects regions upstream of ssrA, ssrB and srfH from DNase I digestion. Furthermore, the C‐terminus of SsrB alone is capable of activating transcription in the absence of the N‐terminus. Results from β‐galactosidase assays indicate that the N‐terminal phosphorylation domain inhibits the C‐terminal effector domain. A previous study from our laboratory reported that ssrA–lacZ and ssrB–lacZ transcriptional fusions were substantially reduced in an ssrB null strain. Results from DNase I protection assays provide direct evidence that SsrB binds at ssrA and ssrB, although the binding sites lie within the transcribed regions. Additional regulators clearly affect gene expression at this important locus, and here we provide evidence that SlyA, a transcription factor that contributes to Salmonella virulence, also affects ssrA/B gene expression.
Axiom of determining transcription start points by RNA polymerase in Escherichia coli
Authors: Lewis Dale E. A. , Adhya Sankar
Published: October 2004

To investigate the determining factors in the selection of the transcription start points (tsp) by RNA polymerase of Escherichia coli, we systematically deleted or substituted single base pairs (bps) at 25 putative critical positions in the two extended −10 promoters, P1 and P2, of the gal operon. These changes extend downstream from −24 to +1 of the P1 promoter. In vitro transcription assays using supercoiled DNA templates revealed a preference for a purine in the non‐template strand for tsp in both promoters. The optimal tsp is the 11th bp counting downstream from the −10 position. A single bp deletion anywhere from −10 to +1 switched the tsp to the next available purine 2–3 bp downstream on the non‐template strand whereas deleting a single bp at position from −24 to −11 did not affect the tsp. The nature of the 10 bp sequence of the −10 to −1 region, while affecting promoter strength, did not influence tsp. The cAMP–CRP complex, which stimulates P1 and represses P2, did not affect the tsp selection process. The rules of tsp selection by RNA polymerase containing σ70 in gal and pyr promoters discussed here may be applicable to others.
Synthesis and AT2 receptor‐binding properties of angiotensin II analogues
Authors: Rosenström U. , Sköld C. , Lindeberg G. , Botros M. , Nyberg F. , Hallberg A. , Karlén A.
Published: October 2004

Abstract:  The present study investigates the importance of the amino acid side chains in the octapeptide angiotensin II (Ang II) for binding to the AT2 receptor. A Gly scan was performed where each amino acid in Ang II was substituted one‐by‐one with glycine. The resulting set of peptides was tested for affinity to the AT2 receptor (porcine myometrial membranes). For a comparison, the peptides were also tested for affinity to the AT1 receptor (rat liver membranes). Only the substitution of Arg2 reduced affinity to the AT2 receptor considerably (92‐fold when compared with Ang II). For the other Gly‐substituted analogues the affinity to the AT2 receptor was only moderately affected. To further investigate the role of the Arg2 side chain for receptor binding, we synthesized some N‐terminally modified Ang II analogues. According to these studies a positive charge in the N‐terminal end of angiotensin III [Ang II (2–8)] is not required for high AT2 receptor affinity but seems to be more important in Ang II. With respect to the AT1 receptor, [Gly2]Ang II and [Gly8]Ang II lacked binding affinity (Ki > 10 μm). Replacement of the Val3 or Ile5 residues with Gly produced only a slight decrease in affinity. Interestingly, substitution of Tyr4 or His6, which are known to be very important for AT1 receptor binding, resulted in only 48 and 14 times reduction in affinity, respectively.
Oral Candida isolates in patients undergoing radiotherapy for head and neck cancer: prevalence, azole susceptibility profiles and response to antifungal treatment
Authors: Belazi M. , Velegraki A. , Koussidou‐Eremondi T. , Andreadis D. , Hini S. , Arsenis G. , Eliopoulou C. , Destouni E. , Antoniades D.
Published: October 2004

Oral pseudomembranous candidiasis and mucositis were assessed in 39 patients receiving a total dose of 39–70 Gy radiotherapy for head and neck cancer. Mucositis was scored using the Radiation Therapy Oncology Group criteria, and oral candidiasis was diagnosed on the basis of clinical evaluation and quantitative laboratory findings. Radiation‐induced mucositis was observed in 9/39 patients. Only 3/39 patients discontinued radiotherapy due to acute severe mucosal effects. Candidiasis (colony‐forming units 35 to ≥60/lesion) associated with mucositis was diagnosed in 30/39 patients: the most frequent aetiology of the infection was Candida albicans (n = 23), followed by Candida glabrata (n = 3), Candida krusei (n = 2), Candida tropicalis (n = 1) and Candida kefyr (n = 1). Patients with confirmed oral pseudomembranous candidiasis were treated with either fluconazole 200 mg/day or itraconazole 200 mg/day for 2 weeks. Clinical improvement and concomitant negative Candida cultures (mycologic cure) were the criteria determining a response to antifungal treatment. Etest revealed very low voriconazole MICs (0.004–0.125 μg/ml) for all isolates, and fluconazole resistance for eight C. albicans strains (MIC > 64 μg/ml) and for the C. krusei isolates (MIC > 32 μg/ml). The same strains showed itraconazole susceptibility dose dependence (MIC 0.5 μg/ml). Despite the itraconazole susceptible dose dependent MIC readings, all patients with oral pseudomembranous candidiasis caused by these strains responded to antifungal treatment with 200 mg/day itraconazole. Oral mycologic surveillance of patients undergoing radiotherapy for head and neck malignancies and susceptibility testing of isolates may be indicated in cases with mucositis‐associated confirmed oral pseudomembranous candidiasis to ensure prompt administration of targeted antifungal treatment. On the basis of the low MIC values found, clinical evaluation of voriconazole is indicated for management of oral pseudomembranous candidiasis refractory to other azoles.
Use of checkerboard DNA–DNA hybridization to study complex microbial ecosystems
Authors: Socransky S. S. , Haffajee A. D. , Smith C. , Martin L. , Haffajee J. A. , Uzel N. G. , Goodson J. M.
Published: October 2004

It has been difficult to conduct large scale studies of microbiologically complex ecosystems using conventional microbiological techniques. Molecular identification techniques in new probe‐target formats, such as checkerboard DNA–DNA hybridization, permit enumeration of large numbers of species in very large numbers of samples. Digoxigenin‐labeled whole genomic probes to 40 common subgingival species were tested in a checkerboard hydridization format. Chemifluorescent signals resulting from the hybridization reactions were quantified using a Fluorimager and used to evaluate sensitivity and specificity of the probes. Sensitivity of the DNA probes was adjusted to detect 104 cells. In all, 93.5% of potential cross‐reactions to 80 cultivable species exhibited signals <5% of that detected for the homologous probe signal. Competitive hybridization and probes prepared by subtraction hybridization and polymerase chain reaction were effective in minimizing cross‐reactions for closely related taxa. To demonstrate utility, the technique was used to evaluate 8887 subgingival plaque samples from 79 periodontally healthy and 272 chronic periodontitis subjects and 8126 samples from 166 subjects taken prior to and after periodontal therapy. Significant differences were detected for many taxa for mean counts, proportion of total sample, and percentage of sites colonized between samples from periodontally healthy and periodontitis subjects. Further, significant reductions were observed post therapy for many subgingival species including periodontal pathogens. DNA probes used in the checkerboard DNA–DNA format provide a useful tool for the enumeration of bacterial species in microbiologically complex systems.
Genotypic diversity of oral Actinomyces naeslundii genospecies 1 and 2 in caries‐active preschool children
Authors: Tang G. , Samaranayake L. P. , Yip H.‐K.
Published: October 2004

A total of 991 isolates of Actinomyces naeslundii were obtained from sound approximal tooth sites in either caries‐active (n = 35) or caries‐free (n = 20) preschool children. From this group of isolates, 101 strains were chosen to study the genotypic diversity of A. naeslundii genospecies 1 (n = 30), catalase‐positive (n = 30), and catalase‐negative genospecies 2 (n = 41). Polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP), with a pair of primers targeting the 16S ribosome RNA gene (16S rDNA), and MnlI digestion together with randomly amplified polymorphic DNA (RAPD) with eight arbitrary, single 10‐mer primers were performed to generate genetic profiles of selected Actinomyces isolates. The hierarchic relationships of genetic profiles were finally analyzed using computerized dendrograms. There was no significant difference in the prevalence rates and proportions of either genospecies 1 or 2 between the caries‐free and caries‐active groups, although a higher prevalence of genospecies 2 was noted in the total population. Dendrogram analyses of the 16S rDNA PCR‐RFLP profiles revealed that all strains belonging to A. naeslundii genospecies 1 could be subgrouped into three genotypes (T7, T18, and T19), with a single predominant genotype, T18 (27/30). Catalase‐positive strains for genospecies 2 fell into three subtypes (T4, T7, and T17), whereas the catalase‐negative counterparts were distributed amongst 16 subtypes. No specific genotype was significantly associated with caries activity. We conclude that heterogeneous subgroups of A. naeslundii genospecies 1 and 2, particularly the latter, are the constituent flora of dental plaque in children and may contribute to the pathogenesis of childhood caries.
Molecular analysis of age‐related changes of Streptococcus anginosus group and Streptococcus mitis in saliva
Authors: Morita E. , Narikiyo M. , Nishimura E. , Yano A. , Tanabe C. , Sasaki H. , Hanada N.
Published: October 2004

The purpose of this study was to survey the prevalence of streptococcal species, especially Streptococcus anginosus (which has been reported to be associated with cancer in the upper digestive tract), Streptococcus constellatus, and Streptococcus intermedius in the saliva of different age groups. A sequence analysis of 16S rDNA was performed and DNA quantified using real‐time polymerase chain reaction. The S. anginosus level increased with age, whereas the levels of S. constellatus and S. intermedius did not change. Streptococcus mitis was the predominant species in the saliva of all the age groups but, unlike the S. anginosus, the proportion of S. mitis in the salivary bacteria decreased with age. The increase in S. anginosus with age should be carefully monitored because of its association with diseases, including cancer.
Alkali‐resistant bacteria in root canal systems
Authors: Nakajo K. , Nakazawa F. , Iwaku M. , Hoshino E.
Published: October 2004

The aim of this study was to isolate and identify alkali‐resistant bacteria from the dentin of infected root canals. Bacteria from homogenized dentin powder made up from infected root canal walls from human teeth were cultured on buffer‐enriched Brain Heart Infusion agar supplemented with 4% sheep blood (BHI‐blood agar), adjusted to pH 7.0, 9.0 or 10.0. Incubation took place for 7 days at 37°C in an anaerobic glove box. Bacterial strains selected according to colony and morphology were subcultured in buffer‐enriched BHI broth adjusted to pH 9.0, 10.0 or 11.0 to confirm their growth as alkali‐resistant bacteria. Polymerase chain reaction amplification using specific primer sets and 16S rDNA sequence analysis was performed for identification of alkali‐resistant isolates. In the present study, 37 teeth extracted from 37 patients were used for preparation of the dentin powder samples. Bacteria were detected in 25 samples when standard BHI‐blood agars (pH 7.0) were used. Of these, 29 strains from 15 samples were alkali resistant, 25 strains growing at pH 9.0 and 4 at pH 10.0. The alkali‐resistant strains included Enterococcus faecium (10 strains) and Enterococcus faecalis (2 strains), Enterobacter cancerogenus (1 strains), Fusobacterium nucleatum (1 strains), Klebsiella ornithinolytica (2 strains), Lactobacillus rhamnosus (2 strains), Streptococcus anginosus (2 strains), Streptococcus constellatus (3 strains), and Streptococcus mitis (2 strains). Three strains were also identified as bacteria of genus Firmicutes or Staphylococcus at the genus level. The present study showed that many bacterial species in infected root canal dentin were alkali‐resistant at pH 9.0 and/or pH 10.0, and belonged mainly to the genus Enterococcus.
Resistance to human β‐defensins is common among oral treponemes
Authors: Brissette C. A. , Simonson L. G. , Lukehart S. A.
Published: October 2004

Background/aims:  Oral treponemes are implicated in the pathogenesis of periodontal disease. We have previously shown that Treponema denticola ATCC type strains and strain GM‐1 are resistant to killing by human β‐defensins (hβD)‐1 and ‐2. We hypothesize that resistance to β‐defensins is a common feature of oral treponemes, which allows colonization and persistence in the oral cavity. In this study, we tested additional isolates of T. denticola, as well as six other species of treponemes, for resistance to hβD‐1, ‐2 and ‐3. We also examined the four ATCC strains of T. denticola and strain GM‐1 for resistance to hβD‐3.

Methods:  Resistance was determined by motility and Alamar Blue assays for metabolic activity.

Results:  All T. denticola strains tested were resistant to hβD‐1, ‐2 and ‐3, with the exception of strain Ambigua, which was sensitive to hβD‐2 and ‐3. All other treponemes except Treponema vincentii were resistant to hβD‐1. Treponema pectinovorum was sensitive to hβD‐2, while T. vincentii, T. pectinovorum and Treponema maltophilum were sensitive to hβD‐3. Escherichia coli was used as a control organism and was killed by all three defensins.

Conclusion:  Resistance to the constitutively expressed hβD‐1 may assist treponemes in initial colonization of epithelial surfaces, while resistance to the inducible hβD‐2 and ‐3 would allow some treponemes to survive in active periodontal lesions.
Differential Implication of Glutathione, Glutathione‐Metabolizing Enzymes and Ascorbate in Tomato Resistance toPseudomonas syringae
Authors: Kuźniak E. , SkŁodowska M.
Published: October 2004

We studied the response of glutathione‐ and ascorbate‐related antioxidant systems of the two tomato cultivars toPseudomonas syringaepv.tomatoinfection. In the inoculated susceptible A 100 cultivar a substantial decrease in reduced glutathione (GSH) content, oxidised glutathione accumulation and GSH redox ratio decline as well as glutathione peroxidase activity increase were found. The enhanced glutathione reductase activity was insufficient to keep the glutathione pool reduced. A transiently increased dehydroascorbic acid (DHA) content and ascorbic acid (AA) redox ratio decrease together with ascorbate peroxidase activity suppression were observed. Adversely to the progressive reduction in GSH pool size, AA content tended to increase but the changes were more modest than those of GSH. By contrast, in interaction with the resistant Ontario cultivar the glutathione pool homeostasis was maintained throughoutP. syringaeattack and no significant effect on the ascorbate pool was observed. Moreover, in the resistant interaction there was a significantly higher constitutive and pathogen‐induced glutathione‐S‐transferase (GST) activity. The relationship between GST activity and DHA content found in this study indicates that this enzyme could also act as dehydroascorbate reductase. These results reflect the differential involvement of GSH and AA in tomato‐P. syringaeinteraction and, in favour of the former, they clearly indicate the role of GSH and GSH‐utilizing enzymes in resistance toP. syringae. The maintenance of glutathione pool homeostasis and GST induction appear to contribute to tissue inaccessibility to bacterial attack.
Localized and Systemic Increase of Phenols in Tomato Roots Induced by Glomus versiforme Inhibits Ralstonia solanacearum
Authors: Zhu H. H. , Yao Q.
Published: October 2004

Ralstonia solanacearum is an important plant pathogen in tropical and subtropical countries. Here, we describe the inhibition of R. solanacearum as a result of increased phenols induced locally or systemically by an arbuscular mycorrhizal (AM) fungus. In pot cultures, R. solanacearum populations in the rhizosphere, on root surfaces and in the xylem were decreased by 26.7, 79.3 and 81.7%, respectively, following inoculation of tomato plants (Lycopersicon esculentum Mill.) with Glomus versiforme Berch. Colonization of the plants by both R. solanacearum and G. versiforme increased the contents of soluble phenols and cell‐wall bound phenols in root tissue, but with different patterns. Whereas R. solanacearum preferably promoted the cell‐wall bound phenol content, G. versiforme preferably enhanced the soluble phenol content. Split root experiments revealed that R. Solanacearum was inhibited by G. versiforme, and that G. versiforme also increased the phenol content systemically, but to a lesser extent than locally.
Molecular Variability of Mycosphaerella graminicola as Detected by RAPD Markers
Authors: Razavi M. , Hughes G. R.
Published: October 2004

A total of 90 isolates of Mycosphaerella graminicola, the cause of septoria tritici leaf blotch of wheat, were tested for DNA polymorphism using 15 decamer random primers. There was a high level of genetic variability among isolates. In 131 random amplified polymorphic DNA (RAPD) fragments, which were produced, 96% were polymorphic. Based on multilocus analysis, 40 different molecular phenotypes were detected. These molecular phenotypes were randomly distributed among sampling sites, suggesting that no clonal structure existed in the population. Cluster analysis showed that the maximum similarity value among isolates was approximately 81% and no identical isolates were detected, indicating that every isolate was a unique genotype. The high degree of DNA polymorphism, the large number of different molecular phenotypes, their random distribution and the results of the cluster analysis all suggested that sexual reproduction has a major role in the genetic structure of M. graminicola in western Canada. The presence of sexual reproduction provides the opportunity for development of new virulent genotypes in the population and suggests that the pathogen may adapt rapidly to any race‐specific sources of resistance. Therefore, when breeding for resistance to M. graminicola, emphasis should be placed on use of non‐race‐specific resistance.
Biocontrol of Rhizoctonia Damping‐off of Tomato by Bacillus subtilis Combined with Burkholderia cepacia
Authors: Szczech M. , Shoda M.
Published: October 2004

Bacillus subtilis strain RB14‐C and Burkholderia cepacia strain BY were used in combination to control damping‐off of tomato plants caused by Rhizoctonia solani. Microcosm tests showed complete inhibition of R. solani growth on filter disks buried in soil added with the mixture of both bacteria. Single BY inhibited the fungus, but not completely, and RB14‐C had only slight inhibitory effect on pathogen growth. The efficacy of this combining treatment was checked in pot experiments, where bacteria were applied to the soil in several combinations: RB14‐C and BY together 4 days before seed planting, RB14‐C 4 days and BY 2 days before seed planting, RB14‐C 4 days and BY immediately before seeds. The effect of these treatments on population of R. solani in soil and infection of plants was compared with the activity of single application of each agent. All bacterial treatments significantly decreased damping‐off of tomato plants. The best control was obtained when BY was added 2 days after RB14‐C. In this treatment plant protection was significantly higher than that obtained in other combined applications and obtained by single strains, except BY added to the soil 4 days before seed planting. The lowest suppression indicated BY introduced to the soil before seed planting. RB14‐C only slightly decreased number of R. solani in the soil. In contrast, BY drastically reduced population of the pathogen. However, there was not a clear relation between decrease of pathogen density in soil and the rate of plant infection. The results show that combination of B. subtilis RB14‐C with B. cepacia BY can lead to greater damping‐off suppression than biocontrol exhibited by these strains used separately, but the effect of combining bacterial agents was clearly related to the order in which both agents were introduced.
Efficacy of Three Natural Chemicals to Reduce the Damage of Erysiphe cichoracearum on Chicory in Two Meteorologically Different Growing Seasons
Authors: Trdan S. , Valič N. , Jerman J. , Ban D. , Žnidarčič D.
Published: October 2004

In two meteorologically quite different years, 2002 and 2003, efficacy of three natural substances with a fungicidal activity (sulphur, soya lecithin, salicylic acid) for control of Erysiphe cichoracearum on chicory was tested. In a block designed field experiment, there were statistically significant differences in the mean index of infection of exterior leaves, in the mean total weight and mean net weight of the plants (= total weight − weight of removed damaged leaves). There was also a significant difference in firmness of the heads of nine chicory varieties that was established in both years. In 2002, when no extreme weather conditions occurred, the fungus spread to a substantially larger extent. Yet no statistically significant differences were found in the efficacy of environmentally friendly fungicidal substances for control of the fungus. In the hotter and drier year of 2003, which was less favourable for spread of the pathogen, sulphur‐containing fungicide was the most effective. In 2002, chicory yield was lower than in 2003. Generally, yield loss due to removal of damaged leaves was from 30.7 to 45.0% in the first year, and from 11.3 to 24.8% in the second. The highest mean total yield and net yield of chicory were in plants, which were treated three times with sulphur‐containing fungicide. In 2002, the most firm heads were in plants treated with sulphur. In 2003, no significant differences among substances were detected. The most infected with the powdery mildew caused by E. cichoracearum, were the less productive varieties of chicory. A statistically significant relationship was not found between the firmness of the heads and the degree of infection. Among different parameters in this experiment, the only relevant and high statistically significant positive correlation (r2 = 0.71) was determined between the total weight of the plants and yield loss of chicory due to infection with the fungus in question.
Identification of Phytoplasmas Associated with Grapevine Yellows in Serbia
Authors: Duduk B. , Botti S. , Ivanović M. , Krstić B. , Dukić N. , Bertaccini A.
Published: October 2004

The molecular identification and characterization of phytoplasmas from infected grapevines in four locations in Serbia are reported. Phytoplasmas were detected and identified by restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction (PCR) amplified 16S rDNA. Grapevine yellows were associated with three molecularly distinguishable phytoplasmas: Flavescence dorée phytoplasmas (elm yellows group: 16SrV‐C subgroup) were present only in the Župa Aleksandrovac region; Bois noir phytoplasmas (stolbur group: 16SrXII‐A subgroup) were detected in the other surveyed regions; a mixed infection of European stone fruit yellows (apple proliferation group: 16SrX‐B subgroup) and Bois noir phytoplasmas was identified in one sample. A finer molecular characterization by RFLP analysis of rpS3 and SecY genes of Flavescence dorée phytoplasmas from Župa Aleksandrovac confirmed that the Serbian genotype is indistinguishable from a strain from the Veneto region, Italy. Characterization of the tuf gene of Bois noir phytoplasmas showed lack of amplification of samples from Erdevik. HpaII profiles of tuf gene PCR products of samples from Pali and Radmilovac were identical, and were indistinguishable from one of the two profiles produced by samples from Italian grapevines used as reference strains.
Etiology of Leaf Chlorosis and Deterioration of the Fruit Interior of Watermelon Plants
Authors: Boubourakas I. N. , Hatziloukas E. , Antignus Y. , Katis N. I.
Published: October 2004

A severe disease with combined symptomatology affecting only grafted watermelon plants appeared in several regions of northern and central Greece during the summers of 1999 and 2000. Disease symptoms included chlorotic mottling followed by pedicel necrosis at a later more mature fruit stage, and finally decomposition of fruit interior. Electron microscopy, double antibody sandwich enzyme‐linked immunosorbent assay tests and reverse transcriptase‐polymerase chain reaction assays identified Cucumber green mottle mosaic virus (CGMMV) as the causal agent. Our studies indicated that the CGMMV isolates from watermelon are closely related to the Israeli variant of CGMMV (CGMMV‐Is). However, bioassays revealed that the Greek isolates elicit symptoms of higher severity and have a wider host range, compared with other described CGMMV isolates. Nucleotide sequence comparison of the movement protein gene of the Greek isolates showed a 97–99% identity with other CGMMV strains. This paper reports the presence of the virus in arable weeds such as Amaranthus blitoides, Amaranthus retroflexus, Heliotropium europaeum, Portulaca oleracea and Solanum nigrum.
Cerebellar Focal Granulomatous Meningoencephalitis in a Dog: Clinical Findings and MR Imaging
Authors: Kitagawa M. , Kanayama K. , Satoh T. , Sakai T.
Published: October 2004

The authors encountered a dachshund dog, presenting vestibular disorder. On magnetic resonance (MR) imaging, a mass showing isointensity on the T1‐ and T2‐weighted images and enhanced by contrast medium, was observed in the right cerebellum. In addition, the periphery of the mass showed isointensity on the T1‐weighted image and hyperintensity on the T2‐weighted image, suggesting sever oedema. Although the dog underwent surgery, it died. The mass was diagnosed pathologically as a granulomatous meningoencephalitis.
Tamoxifen Decreases Level of Immunoglobulins in Blood of the Hen (Gallus domesticus) without Alteration in Non‐Immunoglobular Fractions of Plasma Proteins
Authors: Sechman A. , Hrabia A. , Paczoska‐Eliasiewicz H. , RzĄsa J.
Published: October 2004

The effect of tamoxifen (TMX), an anti‐estrogen compound, on immunoglobulins (Ig) level in blood plasma of laying hens was investigated. TMX (4 mg/hen/day) was given per os for seven consecutive days; control hens received placebo. Blood samples were collected from the wing vein every day before TMX treatment, and plasma Ig levels were measured by means of Ślebodziński's test. TMX significantly decreased plasma Ig levels, maximally by 51% on day 2 of the experiment. The observed reduction in Ig level was accompanied by the significant, 37% decrease in the ratio of Ig/total protein (Tp). From the third day of TMX treatment, level of Ig and the ratio of Ig/Tp gradually increased and on the day 5 of the experiment no difference between control and experimental group was found. In non‐immunoglobular (Tp‐Ig) fractions of plasma proteins no significant alterations after TMX treatment were observed. Therefore, treatment of laying hens with TMX transiently decreased plasma Ig levels. Most likely the effect of TMX is associated with the antagonistic properties of TMX toward estrogen receptors. On the contrary, the transient decrease in plasma Ig levels of TMX‐treated hens followed by the gradual increase suggests adaptation of the immunological system to treatment with the anti‐estrogen preparation.
Meningoencephalomyelitis Caused byNeospora caninumin a Juvenile Fallow Deer (Dama dama)
Authors: Soldati S. , Kiupel M. , Wise A. , Maes R. , Botteron C. , Robert N.
Published: October 2004

Neosporosis, caused by the protozoan parasiteNeospora caninum, is a serious cause of bovine abortion, stillbirth and perinatal death. This paper reports a clinical neosporosis in a 3‐week‐old fallow deer (Dama dama). The fawn was full term and appeared normal at birth. Histological lesions consisted of a multifocal necrotizing and granulomatous meningoencephalomyelitis, with intralesional protozoal cysts. Positive immunohistochemical staining and characteristic PCR products confirmed the diagnosis ofN. caninuminfection.
Survival of Dairy Cows After Surgery to Correct Abomasal Displacement: 1. Clinical and Laboratory Parameters and Overall Survival
Authors: Rohn M. , Tenhagen B.‐A. , Hofmann W.
Published: October 2004

The objective of this study was to compare the clinical and laboratory consequences of left and right displacement of the abomasum (LDA and RDA), short‐ and long‐term survival after surgery and the findings in cows, that could not be cured by omentopexy. Data from 564 cases of displaced abomasum (466 LDA, 98 RDA) were analysed retrospectively. Clinical and laboratory findings were compared between the two manifestations of DA. Survival was assessed after 10 days and after 15 months. Necropsy was carried out on cows that died or were killed.

On arrival at the clinic, left displacement of the abomasum (LDA) cows had been recognized as diseased for longer. LDA occurred earlier in lactation, and more cows with right displacement of the abomasum (RDA) were pregnant. Overall clinical symptoms were more severe in RDA than in LDA cows. Heart rate was higher, body temperature was lower, inanition, abnormal faeces and ruminal stasis were more frequent in RDA cows. Leucocyte counts were higher, and potassium and chloride levels were lower in RDA cows. Acetonuria was more frequent in LDA cows.

More LDA than RDA cows were released from the clinic as cured (82.0% versus 74.5%). However, survival after the early post‐surgical period was similar for RDA and LDA cows. At necropsy, diseases of the gastrointestinal system were the predominant finding in RDA cows, while in LDA cows, diseases of the liver and other concurrent diseases were more important.
cDNA‐AFLP analysis of differential gene expression during the interaction between sugarcane and Puccinia melanocephala
Authors: Carmona E. , Vargas D. , Borroto C. J. , Lopez J. , Fernández A. I. , Arencibia A. , Borrás‐Hidalgo O.
Published: October 2004

Amplified fragment length polymorphism (AFLP) display of complementary DNA (cDNA) was used to identify genes from sugarcane somaclones expressed during the interaction with Puccinia melanocephala. The isolated transcript‐derived fragments (TDFs) correspond to genes involved in the resistance process. Genes related with recognition, signalling and general response were identified through BLAST search. This work constitutes the first report of genes activated during the P. melanocephala‐sugarcane interaction.
Targeted BSA mapping of Scmv1 and Scmv2 conferring resistance to SCMV using PstI/MseI compared with EcoRI/MseI AFLP markers
Authors: Yuan L. , Duble C. M. , Muminovic J. , Melchinger A. E. , Lübberstedt T.
Published: October 2004

In a previous study, two chromosome regions (Scmv1 and Scmv2), conferring sugarcane mosaic virus (SCMV) resistance in maize, were enriched with EcoRI/MseI AFLP (Eco‐AFLP) markers (methylation insensitive) by targeted bulked segregant analysis (tBSA). The objective of the present study was to further saturate these two regions with PstI/MseI AFLP (Pst‐AFLP) markers (methylation sensitive) using the same tBSA approach, and to compare the genomic distribution of both Pst‐AFLP and Eco‐AFLP markers. Out of 470 PstI/MseI primer combinations screened, four Pst‐AFLP markers were identified in the Scmv1 region (chromosome 6), and none in the Scmv2 region (chromosome 3). These Pst‐AFLP markers were more closely linked to the Scmv1a gene than any of the Eco‐AFLP markers, and could be useful for marker‐assisted selection and even map‐based cloning. In addition, Pst‐AFLP and Eco‐AFLP markers were dissimilarly distributed in both target regions. Pst‐AFLP markers were equally distributed across both regions, while Eco‐AFLPs were clustered in the Scmv2 region.
Genetic diversity in cornsalad (Valerianella locusta) and related species as determined by AFLP markers
Authors: Muminovic J. , Melchinger A. E. , Luubberstedt T.
Published: October 2004

Fifteen amplified fragment length polymorphism (AFLP) EcoRI/MseI‐based primer combinations with five selective bases (Eco RI‐ANN, MseI‐CN) were used to estimate genetic diversity among 45 line varieties of cultivated cornsalad and 19 genebank accessions classified into nine different species related to cornsalad. Polymorphic fragments were scored for calculation of Jaccard's coefficient of genetic similarity (GS). The average GS estimate in elite germplasm (GS = 0.90) was substantially higher than in exotic germplasm (GS = 0.47). UPGMA‐cluster analysis revealed genetic relationships among recently bred varieties, old varieties and genebank accessions. Analysis of molecular variance indicated almost threefold variability within sets compared with between sets due to a high level of polymorphism among wild species. Sources for increasing genetic diversity in elite germplasm of cornsalad were suggested and a duplicate among the genebank accessions was detected. AFLPs could be considered a powerful tool for genetic diversity estimation in cornsalad germplasm and are recommended for systematic fingerprinting of remaining cornsalad species.
Over‐expression of Gastrodia anti‐fungal protein enhances Verticillium wilt resistance in coloured cotton
Authors: Wang Y. Q. , Chen D. J. , Wang D. M. , Huang Q. S. , Yao Z. P. , Liu F. J. , Wei X. W. , Li R. J. , Zhang Z. N. , Sun Y. R.
Published: October 2004

Currently there are no adequate control measures for the cotton fungal diseases Verticillium wilt and Fusarium wilt, which are important factors limiting yield under certain conditions. In this study the gene encoding a Gastrodia anti‐fungal protein was introduced into three cultivars of coloured cotton using the method of pollen‐tube pathway transformation, with the purpose of obtaining transgenic plants with improved resistance to wilt. Of the 121 herbicide‐resistant cotton plants two, LB‐5‐8 and ZB‐1‐49, were scored as transgenic based on Southern blot, RT‐PCR analysis and in vitro anti‐fungal activity assay. Field analysis demonstrated that the transgenic lines LB‐5‐8 and ZB‐1‐49 possess an increased resistance to wilt. After 2 years of breeding, the progeny of LB‐5‐8 and ZB‐1‐49 lines still showed a stable and strong resistance to Verticillium wilt. Lines with high levels of resistance to Verticillium wilt obtained from the present study may be widely planted and help to reduce the future impact of cotton wilt on cotton production resulting in increased yields.
Production of an interspecific hybrid between Brassica fruticulosa and B. rapa
Authors: Chandra A. , Gupta M. L. , Banga S. S. , Banga S. K.
Published: October 2004

An interspecific hybrid between a wild species, Brassica fruticulosa (2n = 16, FF) and a crop Brassica species, B. rapa (2n = 20, AA) was synthesized using sequential ovary‐ovule culture on MS medium supplemented with casein hydrolysate. Morphological, molecular and cytogenetic analysis confirmed the true hybrid nature of the offspring. The F1 plants (2n = 18) were intermediate in morphology, highly pollen‐sterile as well as self‐sterile. A maximum of three bivalents per PMC was recorded, but 14 I + 2 II was the most common meiotic configuration. Normal pollen fertility and regular bivalent (18 II) formation was observed in the amphiploid sectors of the hybrid plants. The F1 hybrid harboured significantly lower aphid populations than the crop Brassica parent.
RAPD markers linked with restorer genes for the C‐source of cytoplasmic male sterility in rye (Secale cereale L.)
Authors: Stojałowski S. , Ł Apińaski M. , Masojć P.
Published: October 2004

The study was aimed at the identification of random amplified polymorphic DNA markers linked to genes controlling male sterility in rye with the C‐source of sterility‐inducing cytoplasm. Markers of male sterility were distinguished using bulk segregant analysis, carried out on the two F2 crosses between male sterile and male fertile inbred lines. Screening of polymorphisms revealed by 1000 arbitrary 10‐mer primers allowed the detection of 10 markers in the cross between 711‐cmsC and DS2 lines and seven markers in the cross between 544‐cmsC and Ot0‐20 lines. Five markers were common for the two crosses, which allowed comparative mapping to be performed. Ten markers were mapped on the 4RL chromosome arm where two linked quantitative trait loci (QTL) for male sterility were discovered. Additional QTL of minor effect on male fertility were detected between the two linked markers provisionally assigned to the 6RS chromosome arm. The effectiveness of the marker‐assisted selection (MAS) for male‐sterile genotypes was evaluated.
Novel variation for the tocopherol profile in a sunflower created by mutagenesis and recombination
Authors: Velasco L. , Pérez‐Vich B. , Fernández‐Martínez J. M.
Published: October 2004

α‐Tocopherol is the main tocopherol in sunflower seeds (>90%). Because it exerts a weak antioxidant action in vitro, its partial replacement by other tocopherols is an important breeding objective in this crop. The objective of this research was to develop novel tocopherol profiles in sunflower through mutagenesis and genetic recombination. Seeds of four ‘Peredovik’ accessions were used for chemical mutagenesis with ethyl methane sulfonate (EMS). Single‐seed screening in the M2 generation resulted in two M2 seeds, derived from different M1 plants, with increased γ‐tocopherol contents of 19.2% and 96.7%, respectively. M3 progeny from the M2 seed with the 96.7% content bred true for high c‐tocopherol content, containing more than 90%γ‐tocopherol. M3 progeny from the M2 seed with only 19.2%γ‐tocopherol segregated in a range from 0 to 84.6%. Selection for high c‐tocopherol content produced an M4:5 line, designated IAST‐1, with a stable high concentration of γ‐tocopherol. Crosses between IAST‐1 and T589, with an increased b‐tocopherol content, produced F2 segregants with trans‐gressive levels of up to 77%β‐tocopherol or up to 68% d‐tocopherol. Both novel tocopherol profiles were confirmed in the F3 generation.
QTLs for black‐point resistance in wheat and the identification of potential markers for use in breeding programmes
Authors: Lehmensiek A. , Campbell A. W. , Sutherland M. W. , Williamson P. M. , Michalowitz M. , Daggard G. E.
Published: October 2004

Quantitative trait loci (QTLs) for black‐point resistance have been mapped in two doubled haploid‐derived wheat populations, each thought to contain unrelated sources of resistance. In the ‘Sunco’×‘Tasman’‐derived population, QTLs were located on chromosomes 1D, 2B, 3D, 4A, 5A and 7A with each QTL explaining between 4 and 15% of the observed phenotypic variance. QTLs were contributed by both parents. In the ‘Cascades’×‘AUS1408’‐derived population, QTLs from ‘Cascades’ were identified on chromosomes 2A, 2D and 7A with each QTL explaining between 12 and 18% of the phenotypic variance. Several markers were identified which are promising candidates for use in marker‐assisted selection programmes. If one, two or three of these markers would have been used to select for black‐point resistance in the ‘Sunco’×‘Tasman’ population, then with one marker 34 of 39 resistant lines, with two markers 23 of 32 and with three markers 17 of 32 would have been selected. At the same time, 67 false positives obtained by selecting with one marker are reduced to 24 by selection with two markers and to 11 by selection with three markers. Similarly, if one, two or three markers are used to select for black‐point resistance in the ‘Cascades’×‘AUS1408’ populations, then with one marker 25 of 31 resistant lines, with two markers 26 of 31 and with three markers 10 of 31 are selected. At the same time, 14 false positives are obtained with one marker are reduced to six by selection with two markers and no false positives are selected using three markers.
Inheritance and potentials of a mutated dwarfing gene ndf1 in Brassica napus
Authors: Wang M. L. , Zhao Y. , Chen F. , Yin X. C.
Published: October 2004

A dwarf mutant ‘NDF‐1′, approximately 70 cm high, was derived from a 200‐cm high doubled haploid (DH) line ‘3529’ (Brassica napus), seeds of which were jointly treated with chemical inducers and bombardment of fast neutron. The leaves of the ‘NDF‐1’ mutant were wrinkled and thicker compared with the wild‐type control. The mutant had much lower values than its original parents for all agronomic traits, except for its seed weight. A genetic analysis revealed that dwarfism is under the control of a major gene (designated as ndf1) with a mainly additive effect and non‐significant dominance effect. Because of the high level of resistance to lodging, breeding programmes for double low dwarf oilseed rape and heterosis utilization were initiated. Some new dwarf strains with improved agronomic performance were developed. The hybrid of the cross between the tall parent and the dwarf line showed increased harvest index and significantly higher seed yield than the tall parent or the control variety ‘Zhongyou 821’ and presented an estimated heterosis vigour rate as high as 12.5–25.8%. The dwarf trait will be a promising marker for a simple, economic and efficient way to control the purity of F1 hybrid varieties in hybrid production of B. napus.
Characterization of greenbug resistance in barley
Authors: Porter D. R. , Mornhinweg D. W.
Published: October 2004

The greenbug [Schizaphis graminum (Rondani)] is an extremely damaging pest of barley (Hordeum vulgare L.), particularly in the southern Great Plains of the USA. Winter barley targeted for production in this region should incorporate resistance to greenbug in the form of the resistance gene Rsg1a (in ‘Post 90′) or Rsg2b (in PI 426756). This study was conducted to fully characterize the resistance profile of these two genes against important greenbug biotypes, and to determine which of the two resistance genes is most effective in protecting barley from the greenbug. Eight barley and four wheat cultivars and germplasms were challenged with six greenbug biotypes and damage ratings were recorded for each combination. In five of the six tests, ‘Post 90’ was significantly more resistant than PI 426756 to greenbug feeding damage. Based on the results presented here, we conclude that the resistance gene, Rsg1a, in ‘Post 90’ is the better choice for use in breeding programmes and will provide better protection than Rsg2b against the greenbug.