bluuebunny/crossref_metadata_2025 huggingface dataset:
Stepwise Evolution of Races in Fusarium oxysporum f. sp. ciceris Inferred from Fingerprinting with Repetitive DNA Sequences
Authors: del Mar Jiménez-Gasco María , Milgroom Michael G. , Jiménez-Díaz Rafael M.
Published: May 2007

Plant pathogens often exhibit variation in virulence, the ability to cause disease on host plants with specific resistance, evident from the diversity of races observed within pathogen species. The evolution of races in asexual fungal pathogens has been hypothesized to occur in a stepwise fashion, in which mutations to virulence accumulate sequentially in clonal lineages, resulting in races capable of overcoming multiple host plant resistance genes or multiple resistant cultivars. In this study, we demonstrate a simple stepwise pattern of race evolution in Fusarium oxysporum f. sp. ciceris, the fungus that causes Fusarium wilt of chickpeas. The inferred intraspecific phylogeny of races in this fungus, based on DNA fingerprinting with repetitive sequences, shows that each of the eight races forms a monophyletic lineage. By mapping virulence to each differential cultivar (used for defining races) onto the inferred phylogeny, we show that virulence has been acquired in a simple stepwise pattern, with few parallel gains or losses. Such a clear pattern of stepwise evolution of races, to our knowledge, has not been demonstrated previously for other pathogens based on analyses of field populations. We speculate that in other systems the stepwise pattern is obscured by parallel gains or losses of virulence caused by higher mutation rates and selection by widespread deployment of resistant cultivars. Although chickpea cultivars resistant to Fusarium wilt are available, their deployment has not been extensive and the stepwise acquisition of virulence is still clearly evident.
Role of Phenology in Host Susceptibility and Within-Plant Spread of Stem Rust During Reproductive Development of Perennial Ryegrass
Authors: Pfender W. F.
Published: May 2007

Perennial ryegrass (Lolium perenne) was inoculated with urediniospores of Puccinia graminis subsp. graminicola at four stages of reproductive tiller development. All developmental stages, from expansion of the penultimate leaf through anthesis, were equally susceptible to infection measured as number of pustules per total inoculated plant area. However, within each stage from boot through anthesis, there was a negative correlation of susceptibility with age of host tissue, the highest disease severities occurring on expanding or newly expanded leaves or inflorescences. Within-plant spread of the disease from primary lesions on the flag leaf sheath to the elongating stem of the inflorescence was observed and verified. A single primary infection on the leaf sheath can produce an elongated strip of contiguous secondary infections on the inflorescence head and stem, which is a characteristic sign of stem rust. Position and timing of eruption of the secondary pustules on the stem can be explained by assuming that infections occur on the stem slightly distal to the overlying sheath lesion and erupt one latent period later, by which time tiller elongation has moved the stem infection site upward. Repeated infections occur as the stem elongates, producing contiguous lesions. Expansion rate and final lesion area on the stem were correlated with elongation rate of the inflorescence. Microscopic observation of plant tissue sections revealed that the fungus sporulates on the inner surface of the sheath, and germinating urediniospores are attached to the stem surface under the covering sheath starting 1 to 2 cm distal to the location of the sheath infection site.
Acquisition of Tomato spotted wilt virus by Adults of Two Thrips Species
Authors: de Assis Filho F. M. , Deom C. M. , Sherwood J. L.
Published: May 2007

Only larval thrips that acquire Tomato spotted wilt virus (TSWV), or adults derived from such larvae, transmit the virus. Nonviruliferous adults can ingest virus particles while feeding on TSWV-infected plants, but such adult thrips have not been shown to transmit TSWV. Immunofluorescence microscopy was used to show that thrips 1, 5, 10, and 20 days after adult emergence (DAE) fed on TSWV-infected plants acquired TSWV with virus replication and accumulation occurring in both epithelial and muscle cells of Frankliniella fusca (tobacco thrips [TT]) and F. occidentalis (western flower thrips [WFT]), as indicated by immunodetection of the nonstructural (NSs) protein encoded by the small RNA and the nucleocapsid (N) protein, respectively. Adult WFT acquired TSWV more efficiently than TT. There was no significant effect of insect age on TSWV acquisition by TT. In contrast, acquisition by adult WFT at 1 and 5 DAE was higher than acquisition at 10 and 20 DAE. Subsequent transmission competence of adult cohorts was studied by vector transmission assays. All adult thrips tested that had an acquisition access period as an adult were unable to transmit the virus. These results indicate the susceptibility of adult TT and WFT to infection of midgut cells by TSWV and subsequent virus replication and confirm earlier studies that adult thrips that feed on virus-infected plants do not transmit the virus. The role of a tissue barrier in TSWV movement and infection from midgut muscle cells to the salivary glands is discussed.
Influence of Soil Temperature and Matric Potential on Sugar Beet Seedling Colonization and Suppression of Pythium Damping-Off by the Antagonistic Bacteria Pseudomonas fluorescens and Bacillus subtilis
Authors: Schmidt C. S. , Agostini F. , Leifert C. , Killham K. , Mullins C. E.
Published: May 2007

Pseudomonas fluorescens B5 and Bacillus subtilis MBI 600 colonized sugar beet seedlings at matric potentials of -7 × 103, -140 × 103, and -330 × 103 Pa and under five temperature regimes ranging from 7 to 35°C, with diurnal fluctuations of 5 to 22°C. No interaction between matric potential and temperature was observed. In situ bioluminescence indicated physiological activity of Pseudomonas fluorescens B5. Colonization of the root at ≥4 cm below the seed decreased at very low matric potential (-330 × 103 Pa). Total population size of Pseudomonas fluorescens B5 per seedling was significantly increased at -140 × 103 Pa. However, matric potential had no significant effect on the population density of Pseudomonas fluorescens per gram of root fresh weight and did not affect the distribution of the population down the root. Total population size per seedling and downward colonization by Pseudomonas fluorescens B5 were significantly reduced at high temperatures (25 to 35°C). Maximum colonization down the root occurred at intermediate temperature (15°C) at both matric potentials (-7 × 103 and -140 × 103 Pa). Addition of B. subtilis MBI 600 to the seed had no effect on rhizosphere populations of Pseudomonas fluorescens B5. Populations of B. subtilis MBI 600, which consisted largely of spores, were slightly reduced at lower matric potentials and were not affected by temperature. Survival and dry weight of plants in soils infested with Pythium spp. decreased with increasing soil temperature and matric potential, indicating an increase in disease pressure. However, there was no significant interaction between the two factors. At -330 × 103 Pa, soil dryness but not Pythium infection was the limiting factor for plant emergence. At temperatures of 7 to 25°C and matric potentials of -7 × 103 to 120 × 103 Pa, treatment with Pseudomonas fluorescens B5 increased plant survival and dry weight. At 7°C and -120 × 103 Pa, there was almost complete emergence of seeds treated with Pseudomonas fluorescens B5. Antagonistic activity of Pseudomonas fluorescens B5 decreased with increasing soil temperature and decreasing matric potential. At 25 to 35°C and -7 × 103 Pa, no effect was observed. In regimes with different day and night temperatures, the maximum (day) temperature was decisive for disease development and antagonistic activity. B. subtilis MBI 600 displayed no significant antagonistic effect against Pythium ultimum and did not influence the performance of Pseudomonas fluorescens B5 in combined inocula.
Biopriming of Infected Carrot Seed with an Antagonist, Clonostachys rosea, Selected for Control of Seedborne Alternaria spp.
Authors: Jensen Birgit , Knudsen Inge M. B. , Madsen Mette , Jensen Dan Funck
Published: May 2007

An ecological approach was used to select fungal antagonists effective against the seedborne pathogens Alternaria dauci and A. radicina on carrot. Twenty-five and 105 isolates originating from cereal and carrot habitats were screened against the pathogens in planta, respectively. Irrespective of isolate origin, fungal isolates belonging to Clonostachys rosea controlled pre- and postemergence death caused by A. dauci and A. radicina as effectively as the fungicide iprodione. Isolate IK726 of C. rosea was used in biopriming a seed lot with 29% A. radicina and 11% A. dauci (highly infected), and a seed lot with 4% A. radicina and 7% A. dauci (low infection). Seeds were primed with water alone (hydropriming) or with addition of C. rosea IK726 (biopriming). The occurrence of A. radicina and A. dauci increased twofold and fivefold, respectively, during 14 days hydropriming, irrespective of the initial infection level. On highly infected seed, biopriming reduced the incidence of A. radicina to <2.3% and that of A. dauci to <4.8% while the level of both pathogens was <0.5% on bioprimed seed with a low initial infection rate. In sand stand establishment tests, hydroprimed seeds had a lower healthy seedling stand than nonprimed seeds, mainly due to a high degree of postemergence seedling death. In contrast, biopriming resulted in a seedling stand that was better than that of both nonprimed and hydroprimed seeds. C. rosea IK726 multiplied fivefold to eightfold, and microscopic observations using C. rosea IK726 transformed with a green fluorescent protein (GFP) reporter gene showed that seeds were covered with a fine web of sporulating mycelium of C. rosea. The positive effect of biopriming on healthy seedling stand remained after 5 months of storage at 4°C and IK726 survived at high numbers on these seed. In this study, we demonstrated that bio-priming with the biocontrol strain C. rosea IK726 facilitates priming of infected seeds without risking adverse effects on seedling establishment.
Genetic Diversity and Pathogenic Variation of Common Blight Bacteria (Xanthomonas campestrispv.phaseoliandX. campestrispv.phaseolivar.fuscans) Suggests Pathogen Coevolution with the Common Bean
Authors: Mkandawire Alexander B. C. , Mabagala Robert B. , Guzmán Pablo , Gepts Paul , Gilbertson Robert L.
Published: May 2007

Common bacterial blight (CBB), caused by Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans, is one of the most important diseases of common bean (Phaseolus vulgaris) in East Africa and other bean-growing regions. Xanthomonad-like bacteria associated with CBB in Malawi and Tanzania, East Africa, and in Wisconsin, U.S., were characterized based on brown pigment production, pathogenicity on common bean, detection with an X. campestris pv. phaseoli- or X. campestris pv. phaseoli var. fuscans-specific PCR primer pair, and repetitive element polymerase chain reaction (rep-PCR) and restriction fragment length polymorphism (RFLP) analyses. The common bean gene pool (Andean or Middle American) from which each strain was isolated also was determined. In Malawi, X. campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans were isolated predominantly from Andean or Middle American beans, respectively. In Tanzania, X. campestris pv. phaseoli var. fuscans was most commonly isolated, irrespective of gene pool; whereas, in Wisconsin, only X. campestris pv. phaseoli was isolated from Andean red kidney beans. Three rep-PCR fingerprints were obtained for X. campestris pv. phaseoli strains; two were unique to East African strains, whereas the other was associated with strains collected from all other (mostly New World) locations. RFLP analyses with repetitive DNA probes revealed the same genetic diversity among X. campestris pv. phaseoli strains as did rep-PCR. These probes hybridized with only one or two fragments in the East African strains, but with multiple fragments in the other X. campestris pv. phaseoli strains. East African X. campestris pv. phaseoli strains were highly pathogenic on Andean beans, but were significantly less pathogenic on Middle American beans. In contrast, X. campestris pv. phaseoli strains from New World locations were highly pathogenic on beans of both gene pools. Together, these results indicate the existence of genetically and geographically distinct X. campestris pv. phaseoli genotypes. The rep-PCR fingerprints of X. campestris pv. phaseoli var. fuscans strains from East African and New World locations were indistinguishable, and were readily distinguished from those of X. campestris pv. phaseoli strains. Genetic diversity among X. campestris pv. phaseoli var. fuscans strains was revealed by RFLP analyses. East African and New World X. campestris pv. phaseoli var. fuscans strains were highly pathogenic on Andean and Middle American beans. Breeding for CBB resistance in East African beans should utilize X. campestris pv. phaseoli var. fuscans and New World X. campestris pv. phaseoli strains in order to identify germ plasm with the highest levels of resistance.
Genetic Diversity of Pathogenic and Nonpathogenic Populations of Fusarium oxysporum Isolated from Carnation Fields in Argentina
Authors: Lori Gladys , Edel-Hermann Véronique , Gautheron Nadine , Alabouvette Claude
Published: May 2007

In order to elucidate the origin of Fusarium oxysporum f. sp. dianthi in Argentina, the genetic diversity among pathogenic isolates together with co-occurring nonpathogenic isolates on carnation was investigated. In all, 151 isolates of F. oxysporum were obtained from soils and carnation plants from several horticultural farms in Argentina. The isolates were characterized using vegetative compatibility group (VCG), intergenic spacer (IGS) typing, and pathogenicity tests on carnation. Seven reference strains of F. oxysporum f. sp. dianthi also were analyzed and assigned to six different IGS types and six VCGs. Twenty-two Argentinean isolates were pathogenic on carnation, had the same IGS type (50), and belonged to a single VCG (0021). The 129 remaining isolates were nonpathogenic on carnation and sorted into 23 IGS types and 97 VCGs. The same VCG never occurred in different IGS types. Our results suggest that the pathogen did not originate in the local populations of F. oxysporum but, rather, that it was introduced into Argentina. Given the genetic homogeneity within Argentinean isolates of F. oxysporum f. sp. dianthi, either IGS type or VCG can be used for the identification of the forma specialis dianthi currently in Argentina.
Expression of thePeanut stunt virusCoat Protein Gene Is Essential and Sufficient for Production of Host-Dependent Ribbon-Like Inclusions in Infected Plants
Authors: Bashir N. S. , Sanger M. , Järlfors U. , Ghabrial S. A.
Published: May 2007

We previously have reported that infection of tobacco protoplasts or leaf tissue with the cucumovirus Peanut stunt virus (PSV) induced the production of unusual cytoplasmic ribbon-like inclusions. The formation of these novel inclusions is strain-specific, because infection of tobacco with subgroup II PSV strains, but not subgroup I strains, induced the production of inclusions. Furthermore, we have demonstrated that induction of the ribbon-like inclusions maps to PSV subgroup II RNA3, which codes for the coat protein (CP) and movement protein (MP). We have now extended these studies using chimeric constructs containing CP and MP open reading frames (ORFs) from PSV strains ER and W that belong to subgroups I and II, respectively. Additionally, recombinant Potato virus X (PVX) vectors containing translatable and untranslatable PSV CP ORF were constructed. Plants inoculated with infectious chimeric PSV or recombinant PVX transcripts were analyzed for CP expression by enzymelinked immunosorbent assay and reverse transcription-polymerase chain reaction and for inclusion production by electron microscopy. The results of these experiments indicated that translation of the CP ORF alone is essential and sufficient for inclusion production. In immunogold labeling experiments using an antiserum to PSV virions, abundant gold labeling of the inclusions was observed, suggesting that PSV CP is probably a major component of the inclusions. Because inclusion production is host specific, a host factor is likely to be involved. In addition to their diagnostic importance, these novel inclusions may also prove valuable in identifying the host factors that interact with PSV CP.
Evolution of Sibling Fungal Plant Pathogens in Relation to Host Specialization
Authors: Gudelj I. , Fitt B. D. L. , van den Bosch F.
Published: May 2007

Sibling plant pathogens can be grouped according to their host rangesthe following groups: group 1, sibling pathogens with nonoverlapping host ranges; group 2, sibling pathogens with both overlapping and nonoverlapping host ranges; and group 3, sibling pathogens with overlapping host ranges. Using the adaptive dynamics methodology, we investigated the evolution of sibling pathogens in relation to host specialization for groups 1 to 3. In particular, we focused on the role of multiple host niches and a trade-off in infectivity of pathogens to these hosts on the evolutionary outcome. We have shown that this ecological mechanism can explain only the evolution of sibling pathogens in group 1 and that other ecological and epidemiological mechanisms must be responsible for the evolution of sibling pathogens in the other two groups.
Characterization, In Vitro Culture, and Molecular Analysis of Thecaphora solani, the Causal Agent of Potato Smut
Authors: Andrade Orlando , Muñoz Gastón , Galdames Rafael , Durán Paola , Honorato Rodrigo
Published: May 2007

The fungus Thecaphora solani (syn.: Angiosorus solani), the causal agent of potato smut, was cultivated in vitro for the first time. Teliospores obtained from galls of infected potato plants were used to inoculate commonly used solid and liquid media. The teliospores produced two kinds of vegetative tissue depending on the nutrient status of the media. A very slow radial-growing, hyaline, and septate mycelium, as usually seen in most of the in vitro-cultivated filamentous fungi, was obtained in wateragar medium after 30 to 40 days. On the other hand, a white, sponge-like mycelial mass was obtained in HCM + 1% activated charcoal, and on common potato dextrose agar or malt-yeast-peptone solid or liquid media, after 40 to 50 days under lab conditions. The identity among teliospores and the sponge-like mycelial mass was corroborated by DNA fingerprinting and partial sequencing of the large subunit (LSU) rDNA region. The sexual cycle of the pathogen was completed under lab conditions based on the development of teliospores on the sponge-like mycelial mass. The first attempt to reproduce the disease under controlled conditions was successful, inducing a gall in a cv. Desirée potato explant cultivated in vitro inoculated with radial-growing mycelia. Phylogenetic analysis of LSU rDNA data of the genus Thecaphora and other smut fungi confirmed the initial classification of the pathogen as T. solani.
An Epidemiological Simulation Model with Three Scales of Spatial Hierarchy
Authors: Willocquet Laetitia , Savary Serge
Published: May 2007

An epidemiological model integrating three organizational scales of host plant populations (e.g., sites, leaves, and plants) is presented. At the lowest (site) scale, the model simulates the dynamics of vacant, latent, infectious, and removed sites. Three types of vacant sites are distinguished, depending on presence of infections at higher scales (leaf or plant). The rate of infection of each type of vacant site is computed according to ratios of autodeposition, allo-leaf-deposition, and allo-plantdeposition. At the leaf and plant scales, the rate of victimization is a function of the rate of infection of vacant sites. Sensitivity analyses showed that deposition patterns (the relative proportions of auto-, allo-leaf-, and allo-plant-depositions) and host structure (leaf size and number of leaves per plant) affected the speed of epidemics at the different scales. Model outputs conformed with results from other approaches in the case of random distribution of the disease. The model hypotheses concerning infection from autodeposited propagules, and their implications for disease epidemics, are discussed. The model can be used to derive relationships between allo-deposition ratios and disease incidences at the three scales. These relationships become simple when disease intensity is low. These relationships may be useful, e.g., to assess the potential efficiency of cultivar mixture to control epidemics. Integration of different organization scales and allo-deposition parameters enables the model to capture important features of epidemics developing in space without using explicitly spatialized variables. Such an approach could be useful to analyze other ecological processes that involve a variety of scales.
Spatial Diversity of Setosphaeria turcica Sampled from the Eastern United States
Authors: Ferguson Lisa M. , Carson M. L.
Published: May 2007

Randomly amplified polymorphic DNA (RAPD) markers and mating type were used to examine regional population structure of Setosphaeria turcica in the eastern United States. Of 251 maize-infecting isolates studied, 155 multilocus haplotypes were identified using 21 RAPD markers. Twelve isolates of the most common haplotype were identified from seven states and represented 5.2% of the sample. Although variation in genetic diversity was greatest within states rather than between either regions or states within regions, multidimensional scaling based on average taxonomic distances among state samples showed a close association of samples from IL, OH, IN, IA, MN, MI/WI, and NC. Isolates from GA/SC, VA/TN, PA/NY, and FL were distant from this core group that included midwestern states and NC and were distinct from one another. The high genotypic diversity, near equal mating type frequencies, and gametic phase equilibrium in samples from several states are inconsistent with a strictly clonal population. The population genetic structure of S. turcica is likely the result of both asexual and sexual reproduction. It is not clear whether sexual recombination actually occurs in the eastern United States or occurs elsewhere in tropical America and recombinant genotypes migrate to North America.
A Satellite RNA of Ophiostoma novo-ulmi Mitovirus 3a in Hypovirulent Isolates of Sclerotinia homoeocarpa
Authors: Deng F. , Boland G. J.
Published: May 2007

Two genetically distinct double-stranded RNA (dsRNA) elements were identified in hypovirulent isolates of Sclerotinia homoeocarpa, the causal agent of dollar spot of turfgrass. The large dsRNA (L-dsRNA) was consistently present in all hypovirulent isolates, whereas the small dsRNA (S-dsRNA) was found only in some hypovirulent isolates. Virulence comparisons revealed that there was no significant difference between isolates containing one or both dsRNAs. Therefore, the L-dsRNA appears to be the genetic determinant of hypovirulence, while the S-dsRNA is not essential for hypovirulence in S. homoeocarpa. The L-dsRNA in hypovirulent isolate Sh12B of S. homoeocarpa was previously characterized as a fungal mitochondrial virus and designated Ophiostoma novo-ulmi mitovirus 3a-Sh12B (OnuMV3a-Sh12B) because it was conspecific with O. novo-ulmi mitovirus 3a-Ld from O. novo-ulmi, the causal agent of Dutch elm disease. In the present study, the nucleotide sequences of the S-dsRNAs (738 to 767 nucleotides) in hypovirulent isolates Sh12B, Sh279B, and Sh286B were determined. Nucleotide sequence analysis indicated that the S-dsRNA was not derived from the OnuMV3a dsRNA and it could not encode an RNA-dependent RNA polymerase. These results are consistent with biological data that the S-dsRNA was always associated with the L-dsRNA and was never found independently. Therefore, the S-dsRNA can be regarded as a satellite RNA of OnuMV3a in S. homoeocarpa. Northern blotting analysis indicated that nucleic acid extracts from isolate Sh12B of S. homoeocarpa contained more single (+) stranded RNA than dsRNA for this satellite RNA. The 5′- and 3′-terminal sequences of the positive strand of the S-dsRNA each could be folded into a stem-loop structure and the terminal 21 nucleotides were complementary to each other, potentially forming a panhandle structure.
A New Source of Resistance to Tapesia yallundae Associated with a Homoeologous Group 4 Chromosome in Thinopyrum ponticum
Authors: Li H. J. , Arterburn M. , Jones S. S. , Murray T. D.
Published: May 2007

Wheat (Thinopyrum ponticum line SS767; PI 611939) with 42 chromosomes previously was identified as a new source of eyespot resistance. Individual plants of SS767 were tested for reaction to Tapesia yallundae, the major pathogen of eyespot in the Pacific Northwest region of the United States. Resistance of this line was similar to the resistant winter wheat cv. Madsen (carrying gene Pch1 for eyespot resistance). Polymerase chain reaction analysis with primers specific for the J or E genomes revealed that SS767 contains Thinopyrum chromatin. Cytological and Cbanding analyses demonstrated that SS767 is a chromosome substitution line in which wheat chromosome 4D is replaced by a homoeologous group 4 chromosome of Thinopyrum ponticum. Genomic in situ hybridization using St genomic DNA from Pseudoroegneria strigosa as a probe, which can differentiate chromosomes from different genomes of Thinopyrum, indicated that this chromosome belongs to the J genome. Molecular analysis of an F2 population segregating for chromosome 4J and resistance to eyespot confirmed that eyespot resistance in line SS767 is associated with chromosome 4J of Thinopyrum ponticum. This is the first report of genetic control of resistance to eyespot derived from Thinopyrum ponticum. This source of resistance provides a new opportunity to improve wheat resistance to eyespot by adding to the diversity of resistance sources available.
Glyoxysomal Nature of Microbodies Complexed with Lipid Globules in Botryosphaeria dothidea
Authors: Kim Ki Woo , Park Eun Woo , Kim Kyung Soo
Published: May 2007

The glyoxysomal nature of microbodies was determined in Botryosphaeria dothidea hyphae based on morphology and in situ enzyme characteristics by transmission electron microscopy and cytochemistry. Bound by a single membrane, microbodies had a homogeneous matrix and varied in size ranging from 200 to 400 nm in diameter. Microbodies often had crystalline inclusions that consisted of parallel arrays of fine tubules in their matrices. Microbodies and lipid globules were placed in close association with each other, forming microbody-lipid globule complexes in hyphae. The cytochemical activities of catalase and malate synthase were localized in microbodies, showing intense electron density of the organelle. In addition, immunogold labeling detected the presence of catalase in a multivesicular body-like organelle and the cell wall as well as in the matrix and crystalline inclusion of microbodies, supporting the enzyme secretion outward. Meanwhile, isocitrate lyase was localized only in matrices of microbodies. These results suggest that the microbodies complexed with lipid globules in B. dothidea hyphae are functionally defined as glyoxysomes which may enable the fungus to survive latent periods using lipids via the glyoxylate cycle and catalase secretion.
Mating and Pseudothecial Development in Mycosphaerella citri, the Cause of Citrus Greasy Spot
Authors: Mondal S. N. , Howd D. S. , Brlansky R. H. , Timmer L. W.
Published: May 2007

Greasy spot, caused by Mycosphaerella citri, is a serious disease of citrus in the Caribbean basin. M. citri is a loculoascomycete and produces pseudothecia in decomposing leaves after intermittent wetting and drying. A new in vitro mating technique was developed for production of pseudothecia on sterilized leaf disks in petri dishes. Of the single-ascospore cultures that were recovered from individual asci, four were one mating type and four were a second mating type (tentatively designated mat+ and mat-), indicating that M. citri probably is heterothallic and bipolar like most other loculoascomycetes. Most populations of ascospores recovered from individual leaves or from leaves from groves of different citrus species and various locations had a 1:1 ratio of mating types consistent with random mating. Cytological studies demonstrated that the ontogeny of pseudothecial development was similar to other loculoascomycetes. The formation of mature pseudothecia required 30 to 45 cycles of wetting and drying of infected, dead leaves which required ≈60 to 90 days. The in vitro system for pseudothecial production and the knowledge of the mating system in M. citri will facilitate genetic studies of this important pathogen.
Seasonal variation in rod recapture rates indicates differential exploitation of Atlantic salmon,Salmo salar, stock components
Authors: THORLEY J. L. , YOUNGSON A. F. , LAUGHTON R.
Published: May 2007

Abstract Differential exploitation of the various components of a fish stock can adversely affect the diversity, abundance and long‐term survival of the entire stock. Many anadromous salmonid stocks exhibit a seasonal structuring of their run‐timing that allows fisheries managers to map monthly rod catches onto stock components. To estimate the rod exploitation levels of the various run‐timing groups, fishing guides on the River Spey, Scotland, floy‐tagged 786 rod‐caught and released Atlantic salmon,Salmo salarL., between 2000 and 2002 and recorded recaptures. Whereas 25% of the fish tagged early in March were recaptured, only 2% of those tagged early in June were caught a second time. Exploitation is biased towards the early‐running stock components which current assessments show to be least abundant. Management of Atlantic salmon based on an average exploitation rate is inappropriate.
Improving the upstream passage of two galaxiid fish species through a pipe culvert
Authors: MACDONALD J. I. , DAVIES P. E.
Published: May 2007

Abstract  Movement between habitats in river fish assemblages is often restricted by instream structures such as culverts. The ability of diadromous common jollytail, Galaxias maculatus (Jenyns), and spotted galaxias, Galaxias truttaceus (Val.), to pass upstream through an in situ pipe culvert modified through the installation of baffles was assessed. Spoiler baffles (100 × 70 × 28 or 56 mm) were installed in three spatial arrangements along a 5.5‐m section of the pipe, and individual fish passage assessed at three flow velocities (0.35, 0.70 and 1.0 m s−1). Common jollytails (43–169 mm fork length, FL) were 10 times more successful in passing when baffles were present than under control conditions (baffles absent). Baffle size did not influence success, which increased with the spatial complexity of the baffle arrangement. Across all velocities, common jollytails (46–132 mm FL) and spotted galaxias (55–190 mm FL) were, respectively, 86 and 73 times more successful with the most complex baffle arrangement (overall 80% success) compared with control conditions (overall 13.5% success). Success for both species decreased at higher velocities under control conditions; however, when baffles were present, this trend persisted only for common jollytails. Installing small spoiler baffles may provide a simple, cost‐effective solution to passage problems at culverts.
The presence of germ line mosaicism in cleidocranial dysplasia
Authors: Pal T , Napierala D , Becker TA , Loscalzo M , Baldridge D , Lee B , Sutphen R
Published: May 2007

Cleidocranial dysplasia (CCD) is typically an autosomal dominant condition. The possibility of alternative causes, such as an autosomal recessive form or germ line mosaicism, have been suggested in some families with CCD, but not proven. We present a family consisting of a mother having three sons affected with CCD. One of the affected boys is a half brother to the other two affected children. The diagnosis of CCD was confirmed by DNA analysis of the RUNX2 gene in all three of the boys in blood; however, initial DNA testing in the mother’s blood did not detect the presence of a RUNX2 mutation in the mother. Further testing through heteroduplex analysis applying high‐resolution melting analysis followed by subcloning detected low‐level mosaicism in DNA isolated from maternal blood and buccal swab, confirming low‐level mosaicism in somatic cells. We present the first case of confirmed germ line mosaicism in CCD.
CT scout view as an essential part of CT reading
Authors: Brook OR , Guralnik L , Engel A
Published: May 2007

Computed tomography scout view is a mode of operating a CT system. It is generally used to prescribe CT slices and to display slice locations rather than for direct diagnosis. However, we found that a careful study of CT scout view can contribute significantly to the diagnosis. We show seven abdominal, two chest and two head CT, where the study of CT scout view allowed diagnoses to be made that were not readily apparent from the axial slices.
Ultrasound imaging features of radial scars of the breast
Authors: Lee E , Wylie E , Metcalf C
Published: May 2007

Radial scars of the breast are common benign lesions, which are often radiologically occult. When they are detected by imaging, they are most often found by mammography. Radial scars are usually impalpable and have traditionally been localized for core biopsy and hookwire placement preoperatively by mammographic guidance. Stereotactic biopsy and localization is often difficult. Ultrasound‐guided core biopsies and hookwire placement have the potential to provide a more accurate needle placement. The aim of this study was to determine the proportion of radial scars detectable by ultrasound and the feasibility of carrying out core biopsies and hookwire localization ultrasonographically. A retrospective review of the records of 7236 women was undertaken to determine those who had a histological diagnosis of radial scar. A total of 44 radial scars in 43 women were found, of which 40 had images that were available for analysis. Sixty‐eight per cent of radial scars are visible on ultrasound, most commonly seen as hypoechoic areas/masses. Parenchymal distortion without a hypoechoic mass was seen in 22%. In 8%, the lesion was appreciably better visualized by ultrasound when compared with mammography. In one case, the lesion was detected on ultrasound and not detected by mammography. At least two‐thirds of mammographically detected radial scars can be visualized on ultrasound. These should be submitted to preoperative core biopsy and hookwire localization under ultrasound control.
Nasopharygeal carcinoma in Queensland, Australia: A review of 10 years experience
Authors: Wong CH‐K , Kelly LE , Tripcony LB
Published: May 2007

The purpose of this study was to compare the treatment outcomes of patients with nasopharyngeal carcinoma in Queensland in a 10‐year period during which synchronous chemoradiotherapy has come into use and to compare characteristics of patients of different racial origins and their prognostic factors. Eighty‐one patients treated between 1991 and 2001 at the Queensland Radium Institute, Brisbane, Queensland for histologically confirmed nasopharyngeal carcinoma were included. Seventeen patients were treated using the Intergroup protocol, 32 patients with miscellaneous synchronized chemoradiotherapy, 6 patients with neoadjuvant regimens and 26 patients with radiotherapy only. Asian patients were found to present earlier than White Australian patients (P < 0.02). No significant difference was identified in the histological presentation between the two ethnic groups. Asian patients were more likely to have a relapse and poor loco‐regional control. Overall survival, however, was not different. Patients treated according to the Intergroup protocol had better disease‐specific survival and relapse‐free survival than the other groups. The median follow up was 36 months. Twenty‐five patients (30%) developed recurrent disease. The 5‐year salvage survival or survival after relapse was 15%. Our experience with the Intergroup protocol in our population is similar to other studies, with likelihood of improved results.
Effect of somatostatin on immune inflammatory response in patients with severe acute pancreatitis
Authors: TANG Wen Fu , WANG Yong Gang , ZHU Lin , WAN Mei Hua , CHEN Guang Yuan , XIA Qin , REN Ping , HUANG Xi
Published: May 2007

OBJECTIVE:  Somatostatin regulates immune inflammatory response via apoptosis and adhesion of leukocytes in many diseases. This article reported a study that aimed to observe the mechanism and effect of somatostatin on the immune inflammatory response through apoptosis and adhesion of leukocytes in severe acute pancreatitis.

METHODS:  Thirty‐eight patients with severe acute pancreatitis, that fulfilled the guidelines for the treatment of severe acute pancreatitis of China and Balthazar computed tomography severity index (≥5) were enrolled consecutively. Nineteen of these patients received our routine treatment and 19 received additional somatostatin. In all patients the expressions of CD4, CD8, CD95/CD95 ligand and CD18/CD62 ligand on leukocytes were determined by flow cytometry, both upon admission and on the fourth day. Thirty healthy volunteers constituted the normal healthy group.

RESULTS:  In the treatment group, CD4, CD4 : CD8 ratio and CD62 ligand on leukocytes increased from 11.4 ± 8.2, 0.47 ± 0.10 and 25.5 ± 9.2 to 22.1 ± 9.7, 0.68 ± 0.11 and 36.2 ± 11.7 (P < 0.05) respectively, while CD95 ligand on both lymphocyte and polymorphonuclear cells increased from 0.65 ± 0.21 and 0.76 ± 0.29 to 1.18 ± 0.32 and 1.58 ± 0.43 after treatment with somatostatin (P < 0.05). Furthermore, lactate dehydrogenase, aspartate aminotransferase, amylase, C reactive protein and acute physiology and chronic healthy evaluation (APACHE II) score in the treatment group reduced faster than those in the control group (P < 0.05), though there was no difference in mortality (15.7%vs 5.3%) between the two patient groups (P > 0.05).

CONCLUSION:  Somatostatin can modulate the immune inflammatory response and the severity of severe acute pancreatitis through apoptosis and adhesion of leukocytes, but this modulatory effect by itself is not strong enough to improve the final.
Lymphadenopathy, elevated liver function tests and weight loss in a 68‐year‐old man
Authors: KROK Karen L , TORBENSON Micheal S , SCHULICK Richard D , THULUVATH Paul J
Published: May 2007

A 68‐year‐old man presented to the hospital with fevers, weight loss, lymphadenopathy and abnormal liver‐associated enzymes. After a thorough workup, a liver biopsy demonstrated histiocytes with phagocytosis of the lymphocytes and a positive immunostain for S‐100. The diagnosis of Rosai‐Dorfman disease was made. This case report will discuss the patient's presentation as well as the diagnosis and treatment of this rare, non‐malignant disorder, which only rarely affects the liver.
Short‐Term Traffic Volume Forecasting Using Kalman Filter with Discrete Wavelet Decomposition
Authors: Xie Yuanchang , Zhang Yunlong , Ye Zhirui
Published: May 2007

Abstract:  This article investigates the application of Kalman filter with discrete wavelet analysis in short‐term traffic volume forecasting. Short‐term traffic volume data are often corrupted by local noises, which may significantly affect the prediction accuracy of short‐term traffic volumes. Discrete wavelet decomposition analysis is used to divide the original data into several approximate and detailed data such that the Kalman filter model can then be applied to the denoised data and the prediction accuracy can be improved. Two types of wavelet Kalman filter models based on Daubechies 4 and Haar mother wavelets are investigated. Traffic volume data collected from four different locations are used for comparison in this study. The test results show that both proposed wavelet Kalman filter models outperform the direct Kalman filter model in terms of mean absolute percentage error and root mean square error.
Nonlinear Analysis of Steel Cable‐Stayed Bridges
Authors: Song Weon‐Keun , Kim Seung‐Eock , Ma Sang Soo
Published: May 2007

Abstract:  In this study, a nonlinear inelastic analysis model using a softening plastic‐hinge approach is proposed for predicting the ultimate load‐carrying capacity of steel cable‐stayed bridges. The ultimate load‐carrying capacity analysis is done starting from the initial shape determination due to bridge dead load. The proposed model can consider both geometric and material nonlinearities in the nonlinear inelastic analysis for the example bridges. The load–displacement curves of the example bridges predicted by both the proposed model and the commercial code ABAQUS are compared with each other to verify the accuracy of solutions. Identical solutions between them are found. A parametric study on the example bridges is presented and their ultimate behavior is discussed.
HUME ON KNOWLEDGE, CERTAINTY AND PROBABILITY: ANTICIPATING THE DISINTEGRATION OF THE ANALYTIC/SYNTHETIC DIVIDE?
Authors: MEEKER KEVIN
Published: May 2007

Abstract:  This paper contends that the first argument of Hume's “Of scepticism with regard to reason” entails that humans have no knowledge as Hume understands knowledge. In defending this claim, we also see how Hume's argument anticipates an important aspect of an extremely influential 20th century development: the collapse of the analytic/synthetic distinction.
Minimal role for activating transcription factor 3 in the oligodendrocyte unfolded protein response in vivo
Authors: Sharma Ramaswamy , Jiang HuiYuan , Zhong Laura , Tseng James , Gow Alexander
Published: May 2007

To further our goal of identifying and characterizing the functions of major components of the unfolded protein response (UPR) in oligodendrocytes, the gene encoding the activator of transcription factor 3 protein (ATF3) has been ablated in mice expressing mutant forms of the Proteolipid protein 1 (Plp1) gene and the phenotype of double mutants characterized at several levels. Mature oligodendrocytes in Plp1 mutant mice undergo UPR‐induced cell stress, induce ATF3 expression and exhibit a greater propensity to die by apoptosis, which is consistent with pro‐death function of ATF3 proposed from in vitro studies. However, we find that the absence of ATF3 has no effect on the levels of apoptosis in Plp1 mutants. Furthermore, we find that oligodendrocyte function appears normal in Atf3−/− mice and that motor coordination and neural communication are similarly unaffected. Accordingly, we conclude that ATF3, at best, plays a minor role in UPR signaling and its expression is more likely induced by the UPR as a secondary event in oligodendrocytes that is unrelated to cell death.
Sexual or Friendly? Associations About Women, Men, and Self
Authors: Lindgren Kristen P. , Shoda Yuichi , George William H.
Published: May 2007

Using explicit, self-report measures, past research has found that heterosexual men, relative to heterosexual women, often attribute more sexuality to women's behaviors. In the present studies, the Implicit Association Test was used to determine if these findings held at the automatic processing level. The results of Study 1 were consistent with past research: Men, compared to women, had more sexual and less friendly automatic associations with the concept of women. Gender differences, however, were not observed in associations with the concept of self or men. Study 2 investigated how exposure to a dating context affected these associations. Associations about the self became more sexualized after reading about a first date, regardless of the participants' gender. However, for opposite-sex others, men's associations became less sexualized whereas women's associations became more sexualized. Collectively, these studies shed light on chronic and temporarily activated automatic processes relevant to sexual perception and contexts in which women are oversexualized.
Characterization of 20 microsatellite marker loci in the red‐bellied brown lemur (Eulemur rubriventer)
Authors: ANDRIANTOMPOHAVANA R. , MORELLI T. L. , BEHNCKE S. M. , ENGBERG S. E. , BRENNEMAN R. A. , LOUIS E. E.
Published: May 2007

Twenty nuclear microsatellite loci were isolated from a genomic DNA library derived from a free‐ranging red‐bellied brown lemur (Eulemur rubriventer), from the Ranomafana National Park, Madagascar. Population genetic parameters were estimated as baseline values from samples collected from populations harboured in the Ranomafana and Andringitra National Parks. The marker suite will be used in a future study on the population dynamics of this species.
Urban Plants as Genetic Reservoirs or Threats to the Integrity of Bushland Plant Populations
Authors: ROBERTS DAVID G. , AYRE DAVID J. , WHELAN ROBERT J.
Published: May 2007

Abstract:  Remnant plants in urban fringes and native plants in gardens have the potential to contribute to the conservation of threatened plants by increasing genetic diversity, effective size of populations, and levels of genetic connectedness. But they also pose a threat through the disruption of locally adapted gene pools. At Hyams Beach, New South Wales, Australia, four bushland stands of the rare shrub, Grevillea macleayana McGillivray, surround an urban area containing remnant and cultivated specimens of this species. Numbers of inflorescences per plant, fruits per plant, and visits by pollinators were similar for plants in urban gardens and bushland. Urban plants represented a substantial but complex genetic resource, displaying more genetic diversity than bushland plants judged byHe, numbers of alleles per locus, and number of private alleles. Of 27 private alleles in urban plants, 17 occurred in a set of 19 exotic plants. Excluding the exotic plants, all five stands displayed a moderate differentiation (FST= 0.14 ± 0.02), although the urban remnants clustered with two of the bushland stands. These patterns may be explained by high levels of selfing and inbreeding in this species and by long‐distance dispersal (several seeds in the urban stand were fathered by plants in other stands). Genetic leakage (gene flow) from exotic plants to 321 seeds on surrounding remnant or bushland plants has not occurred. Our results demonstrate the conservation value of this group of urban plants, which are viable, productive, genetically diverse, and interconnected with bushland plants. Gene flow has apparently not yet led to genetic contamination of bushland populations, but high levels of inbreeding would make this a rare event and difficult to detect. Remnant plants in urban gardens could successfully contribute to recovery plans for endangered and vulnerable species.