bluuebunny/crossref_metadata_2025 huggingface dataset:
Trends in rainfall associated with sources of air pollution
Authors: Bigg E.Keith
Published: February 2009

Environmental context. Decreasing trends in rainfall over large areas of eastern and south-western Australia have resulted in critical water shortages. Three reasons have been suggested. The first is a change in atmospheric circulation as a result of greenhouse gas forcing. The second is that changes in land usage have affected surface moisture, albedo and cloud formation. Another, the subject of this study, is that airborne particulates associated with urban areas have acted to decrease the mean efficiency of rainfall, the growth of urban areas thereby causing an underlying decreasing trend in rainfall.
Abstract. Trends in rainfall in the 35 years 1970–2004 have been calculated for all 350 available rainfall stations having sufficiently complete records that lie between latitudes 26–30°S and longitudes 150–154°E. The area contains two major urban centers, Brisbane with a rapidly growing population approaching two million and the Gold Coast with a population of ~500 000. Statistically highly significant negative trends were found in the vicinity of Brisbane, with decreases exceeding 40% of mean daily rainfall in the 35 years, and in a smaller area inland from the Gold Coast. The spatial distribution of trends was consistent with aerosol production from human activities, the prevailing winds and losses due to the topography. A previously published observation using satellite data showed that cloud properties were affected by urban aerosols in a way that is likely to reduce precipitation. The results of this study reinforce the suggestion made then that monitoring of aerosol concentrations and properties and in-situ observations of rain formation processes in the area should be undertaken as a matter of urgency.
Fitzroy River Basin, Queensland, Australia. III. Identification of sediment sources in the coastal zone
Authors: Smith J. , Douglas G. B. , Radke L. C. , Palmer M. , Brooke B. P.
Published: February 2009

Environmental context. The Fitzroy River Basin is a major source of suspended sediment and nutrients to the southern Great Barrier Reef lagoon. A reduction in sediment and nutrient loads is necessary to protect coastal reefs and this requires an understanding of the sediment sources. The present geochemical and modelling study provides a quantitative estimate of the spatial and temporal variations in the sources of sediment deposited in the Fitzroy River coastal zone.
Abstract. Sediment sources to the Fitzroy River coastal zone have been identified and quantified using an integrated geochemical and modelling approach. The coastal sediments display little geochemical variation as a result of substantial homogenisation during hydrodynamic processes and indicate a sediment composition consistent with derivation from mixed catchment sources. A lack of substantial temporal geochemical variation in the sediment records indicates weathering regimes and hydrodynamic transport have been relatively consistent throughout the Holocene. Despite this apparent geochemical homogeneity, a modelling approach using a Bayesian statistical model revealed changes in catchment sediment sources over time. Variations in the occurrence and intensity of rainfall events in different parts of the catchment as well as land-use changes following European settlement are likely to have had a substantial effect on the relative contributions of the catchment sources delivered to and deposited in the coastal zone. Additionally, large variations in flow events and variable estuary hydrodynamics result in different catchment soil types being delivered and deposited under different conditions. The present study found that basaltic material is the dominant catchment source in the coastal surface sediments with an estimated enrichment of ~3 relative to catchment and estuary abundances. Basaltic soils present as a more recent and extensive, weathered surficial cover are more readily mobilised than other catchment soils and will be transported further within freshwater flood plumes. It is likely that in large flood events, this basaltic material may reach the coral-dominated outer shelf. Improved land management practices to reduce sediment loads can be targeted to the areas supplying the majority of sediment to the coastal zone.
A three-dimensional reactive transport model for sediments, incorporating microniches
Authors: Sochaczewski Łukasz , Stockdale Anthony , Davison William , Tych Wlodek , Zhang Hao
Published: February 2009

Environmental context. Modelling of discrete sites of diagenesis in sediments (microniches) has typically been performed in 1-D and has involved a limited set of components. Here we present a new 3-D model for microniches within a traditional vertical sequence of redox reactions, and show example modelled niches of a range of sizes, close to the sediment–water interface. Microniche processes may have implications for understanding trace metal diagenesis, via formation of sulfides. The model provides a quantitative framework for examining microniche data and concepts. Abstract. Most reactive transport models have represented sediments as one-dimensional (1-D) systems and have solely considered the development of vertical concentration gradients. However, application of recently developed microscale and 2-D measurement techniques have demonstrated more complicated solute structures in some sediments, including discrete localised sites of depleted oxygen, and elevated trace metals and sulfide, referred to as microniches. A model of transport and reaction in sediments that can simulate the dynamic development of concentration gradients occurring in 3-D was developed. Its graphical user interface allows easy input of user-specified reactions and provides flexible schemes that prioritise their execution. The 3-D capability was demonstrated by quantitative modelling of hypothetical solute behaviour at organic matter microniches covering a range of sizes. Significant effects of microniches on the profiles of oxygen and nitrate are demonstrated. Sulfide is shown to be readily generated in microniches within 1 cm of the sediment surface, provided the diameter of the reactive organic material is greater than 1 mm. These modelling results illustrate the geochemical complexities that arise when processes occur in 3-D and demonstrate the need for such a model. Future use of high-resolution measurement techniques should include the collection of data for relevant major components, such as reactive iron and manganese oxides, to allow full, multicomponent modelling of microniche processes.
Arsenobetaine is a significant arsenical constituent of the red Antarctic alga Phyllophora antarctica
Authors: Grotti Marco , Soggia Francesco , Lagomarsino Cristina , Goessler Walter , Francesconi Kevin A.
Published: February 2009

Environmental context. Although arsenic occurs in marine animals at high concentrations, the pathways by which it is biotransformed and accumulated remain largely unknown. The observation that some species of algae can contain significant concentrations of arsenobetaine, a major marine arsenic species, is relevant to explanations of the source of this compound to marine animals and its transport through the marine food web.
Abstract. Significant amounts of arsenobetaine (up to 0.80 μg As g–1 dry mass, representing 17% of the extractable arsenic) were found in the extracts of all four samples of the red alga Phyllophora antarctica collected from two sites in Antarctica (Terra Nova Bay and Cape Evans). The assignment was made with high performance liquid chromatography–inductively coupled plasma mass spectrometry (HPLC-ICPMS) based on exact cochromatography with a standard compound with two chromatographic systems (cation-exchange and ion-pairing reversed-phase), each run under two sets of mobile phase conditions. Particular care was taken during sample preparation to ensure that the arsenobetaine was of algal origin and did not result from epiphytes associated with the alga. Another red alga, Iridaea cordata, collected from Terra Nova Bay, did not contain detectable concentrations of arsenobetaine. For both algal species, the majority of the extractable arsenic was present as arsenosugars. Confirmation that marine algae can contain significant amounts of arsenobetaine allows a simpler explanation for the widespread occurrence of this arsenical in marine animals.
HIV risk practices sought by men who have sex with other men, and who use internet websites to identify potential sexual partners
Authors: Klein Hugh
Published: February 2009

Men who have sex with men (MSM) account for the largest number of persons diagnosed with AIDS in the USA, with higher than average rates of drug use and unprotected sex being cited as the principal reasons underlying their high rates of HIV infection. Recent evidence has suggested that the use of websites specifically designed to promote unsafe sexual practices may be particularly common among MSM, thereby fostering their risky behaviours. In light of these findings, the present study is based on a content analysis of 1316 ads/profiles posted on one of the most popular MSM websites that specifically fosters unprotected sex. Ads/profiles were selected randomly based on the American ZIP code of residence. Data were collected between September 2006 and January 2007. Rates of advertised for high-risk sexual behaviours were very high, particularly for oral sex involving ejaculation into the mouth (88.0% for receptive oral sex, 77.4% for insertive oral sex), anal sex involving ejaculation into the anus (79.7% for insertive anal sex, 69.4% for receptive anal sex), multiple partner sex (77.9%) and felching (16.5%). A multivariate analysis of the correlates of sexual risk preferences identified seven factors that were related to a propensity towards enhanced sexual risk: younger age (β = 0.12, P = 0.0001), not being African American (β = 0.05, P = 0.0341), self-identification as a sexual ‘bottom’ (β = 0.20, P = 0.0001), not caring about one’s potential sex partners’ HIV serostatus (β = 0.15, P = 0.0001), preferring to have sex while under the influence of drugs (β = 0.08, P = 0.0022), a greater involvement in and commitment to the use of the website to locate potential unprotected sex partners (β = 0.16, P = 0.0001) and not being HIV-negative (β = 0.08, P = 0.0081). The HIV intervention-related implications of these findings are discussed.
Pending research issues in male condom use promotion
Authors: Crosby Richard , Warner Lee
Published: February 2009

Sufficient evidence has accumulated to warrant the expansion of condom use research in several additional directions. Possible risk compensation pertaining to human papillomavirus vaccination and vaginal microbicides is one example. A second area of needed research involves the question of when couples can be advised to safely discontinue condom use given that ‘lifelong’ condom use is not a realistic goal for most people. A third example is intensified research designed to identify more effective means of mass marketing condoms and their use as a health-protective behaviour. As the AIDS and sexually transmissible infection pandemics persist, intensified condom promotion research is an ethical imperative.
Temporal and spatial structure in a daily wildfire-start data set from the western United States (1986 - 96)
Authors: Bartlein P. J. , Hostetler S. W. , Shafer S. L. , Holman J. O. , Solomon A. M.
Published: February 2009

The temporal and spatial structure of 332 404 daily fire-start records from the western United States for the period 1986 through 1996 is illustrated using several complimentary visualisation techniques. We supplement maps and time series plots with Hovmöller diagrams that reduce the spatial dimensionality of the daily data in order to reveal the underlying space–time structure. The mapped distributions of all lightning- and human-started fires during the 11-year interval show similar first-order patterns that reflect the broad-scale distribution of vegetation across the West and the annual cycle of climate. Lightning-started fires are concentrated in the summer half-year and occur in widespread outbreaks that last a few days and reflect coherent weather-related controls. In contrast, fires started by humans occur throughout the year and tend to be concentrated in regions surrounding large-population centres or intensive-agricultural areas. Although the primary controls of human-started fires are their location relative to burnable fuel and the level of human activity, spatially coherent, weather-related variations in their incidence can also be noted.
Climate effects on historical fires (1630 - 1900) in Utah
Authors: Brown Peter M. , Heyerdahl Emily K. , Kitchen Stanley G. , Weber Marc H.
Published: February 2009

We inferred climate effects on fire occurrence from 1630 to 1900 for a new set of crossdated fire-scar chronologies from 18 forested sites in Utah and one site in eastern Nevada. Years with regionally synchronous fires (31 years with fire at ≥20% of sites) occurred during drier than average summers and years with no fires at any site (100 years) were wetter than average. Antecedent wet summers were associated with regional-fire years in mixed-conifer and ponderosa pine forest types, possibly by affecting fine fuel amount and continuity. NINO3 (an index of the El Niño–Southern Oscillation, ENSO) was significantly low during regional-fire years (La Niñas) and significantly high during non-fire years (El Niños). NINO3 also was high during years before regional-fire years. Although regional fire years occurred nearly twice as often as expected when NINO3 and the Pacific Decadal Oscillation were both in their cool (negative) phases, this pattern was not statistically significant. Palmer Drought Severity Index was important for fire occurrence in ponderosa pine and mixed-conifer forests across the study area but ENSO forcing was seen only in south-eastern sites. Results support findings from previous fire and climate studies, including a possible geographic pivot point in Pacific basin teleconnections at ~40°N.
Climatic influences on fire regimes in montane forests of the southern Cascades, California, USA
Authors: Taylor A. H. , Trouet V. , Skinner C. N.
Published: February 2009

The relationship between climate variability and fire extent was examined in montane and upper montane forests in the southern Cascades. Fire occurrence and extent were reconstructed for seven sites and related to measures of reconstructed climate for the period 1700 to 1900. The climate variables included the Palmer Drought Severity Index (PDSI), summer temperature (TEMP), NINO3, a measure of the El Niño–Southern Oscillation (ENSO), and the Pacific Decadal Oscillation (PDO). Fire extent at the site and regional scale was associated with dry and warm conditions in the year of the fire and regional fire extent was not associated with ENSO or PDO for the full period of analysis. The relationship between regional fire extent and climate was not stable over time. The associations of fire extent with PDSI and TEMP were only significant from ~1775 onward and the associations were strongest between 1805 and 1855. PDO and fire extent were also associated during the 1805–1855 period, and ENSO was associated with fire extent before 1800, but not after. The interannual and interdecadal variability of the fire response to temperature and drought suggests that increased periods of regional fire activity may occur when high interannual PDSI variation coincides with warm decades.
Computer‐Aided Diagnosis of Multiple Sclerosis
Authors: Linder R. , Mörschner D. , Pöppl S. J. , Moser A.
Published: February 2009

The study aims to develop a computer‐assisted decision support based on cerebrospinal fluid (CSF) and blood findings to improve their value and ease the diagnostic procedure of chronic inflammatory diseases (CIDs) of central nervous system (CNS). Data were collected from patients suffering from multiple sclerosis (MS, n = 73), from another CID of the CNS (n = 22), or a psychiatric disease (control group, CTRL, n = 12). Univariate and multivariate analyses were performed using multiple logistic regression and artificial neural networks. Differentiating between MS and CID, no parameter could be disclosed that could provide a meaningful decision support. However, multivariate analysis obtained a statistically significant classification (sensitivity = 84.9%, specificity = 54.5%, p < 0.001). On the contrary, multivariate analysis based on the differentiation between MS vs. CTRL, gave good results (sensitivity = 95.9%, specificity = 83.3%, p < 0.001). It became evident from standard laboratory findings that there is a significant potential for computer‐aided decision support.
Linear Latent Structure Analysis and Modelling of Multiple Categorical Variables
Authors: Akushevich I. , Kovtun M. , Manton K. G. , Yashin A. I.
Published: February 2009

Linear latent structure analysis is a new approach for investigation of population heterogeneity using high‐dimensional categorical data. In this approach, the population is represented by a distribution of latent vectors, which play the role of heterogeneity variables, and individual characteristics are represented by the expectation of this vector conditional on individual response patterns. Results of the computer experiments demonstrating a good quality of reconstruction of model parameters are described. The heterogeneity distribution estimated from 1999 National Long Term Care Survey (NLTCS) is discussed. A predictive power of the heterogeneity scores on mortality is analysed using vital statistics data linked to NLTCS.
How to Obtain Long Term Projections for Smoking Behaviour: A Case Study in the Dutch Population
Authors: Capannesi Maurizio , Boshuizen Hendriek C. , Willemsen Marc C. , van Houwelingen Hans C.
Published: February 2009

A state‐transition model is presented to project the prevalence rates of never, current and former smokers within the Dutch population. Changes are determined by the transition rates among these three classes: start rates, quit rates and relapse rates. Both the initial prevalence rates and transition rates are calculated from cross‐sectional data using a restricted quadratic multinomial regression spline and a restricted quadratic logistic regression spline, respectively. Through a Monte Carlo experiment an uncertainty analysis was performed to assess the level of reliability of the results, while a sensitivity analysis was carried out in order to detect the input variables that mostly contribute to the output variability. The results obtained through this model show a considerable but rather slow decrease of smokers up to year 2050.
Modelling of Anti‐Tumour Immune Response: Immunocorrective Effect of Weak Centimetre Electromagnetic Waves
Authors: Isaeva O. G. , Osipov V. A.
Published: February 2009

We formulate the dynamical model for the anti‐tumour immune response based on intercellular cytokine‐mediated interactions with the interleukin‐2 (IL‐2) taken into account. The analysis shows that the expression level of tumour antigens on antigen presenting cells has a distinct influence on the tumour dynamics. At low antigen presentation, a progressive tumour growth takes place to the highest possible value. At high antigen presentation, there is a decrease in tumour size to some value when the dynamical equilibrium between the tumour and the immune system is reached. In the case of the medium antigen presentation, both these regimes can be realized depending on the initial tumour size and the condition of the immune system. A pronounced immunomodulating effect (the suppression of tumour growth and the normalization of IL‐2 concentration) is established by considering the influence of low‐intensity electromagnetic microwaves as a parametric perturbation of the dynamical system. This finding is in qualitative agreement with the recent experimental results on immunocorrective effects of centimetre electromagnetic waves in tumour‐bearing mice.
Kinetochore-generated pushing forces separate centrosomes during bipolar spindle assembly
Authors: Toso Alberto , Winter Jennifer R. , Garrod Ainslie J. , Amaro Ana C. , Meraldi Patrick , McAinsh Andrew D.
Published: February 2009

In animal somatic cells, bipolar spindle formation requires separation of the centrosome-based spindle poles. Centrosome separation relies on multiple pathways, including cortical forces and antiparallel microtubule (MT) sliding, which are two activities controlled by the protein kinase aurora A. We previously found that depletion of the human kinetochore protein Mcm21RCENP-O results in monopolar spindles, raising the question as to whether kinetochores contribute to centrosome separation. In this study, we demonstrate that kinetochores promote centrosome separation after nuclear envelope breakdown by exerting a pushing force on the kinetochore fibers (k-fibers), which are bundles of MTs that connect kinetochores to centrosomes. This force is based on poleward MT flux, which incorporates new tubulin subunits at the plus ends of k-fibers and requires stable k-fibers to drive centrosomes apart. This kinetochore-dependent force becomes essential for centrosome separation if aurora A is inhibited. We conclude that two mechanisms control centrosome separation during prometaphase: an aurora A–dependent pathway and a kinetochore-dependent pathway that relies on k-fiber–generated pushing forces.
The biological sciences in India
Authors: Vale Ronald D. , Dell Karen
Published: February 2009

India is gearing up to become an international player in the life sciences, powered by its recent economic growth and a desire to add biotechnology to its portfolio. In this article, we present the history, current state, and projected future growth of biological research in India. To fulfill its aspirations, India's greatest challenge will be in educating, recruiting, and supporting its next generation of scientists. Such challenges are faced by the US/Europe, but are particularly acute in developing countries that are racing to achieve scientific excellence, perhaps faster than their present educational and faculty support systems will allow.
The ftsZ Gene of the Endocellular Bacterium ‘Candidatus Glomeribacter gigasporarum’ Is Preferentially Expressed During the Symbiotic Phases of Its Host Mycorrhizal Fungus
Authors: Anca Iulia-Andra , Lumini Erica , Ghignone Stefano , Salvioli Alessandra , Bianciotto Valeria , Bonfante Paola
Published: February 2009

The arbuscular mycorrhizal fungus (AM) Gigaspora margarita consistently hosts bacteria, named ‘Candidatus Glomeribacter gigasporarum,’ inside its cytoplasm. Endobacteria have a positive impact on fungal fitness during the presymbiotic phase, prior to plant roots colonization. We tested the hypothesis that the endobacterium and its cell divisions depend on fungal metabolism, mirroring also the events of the fungal life cycle which are influenced by plant signals. We first cloned a fragment of ftsZ, a marker gene for bacterial division, and then analyzed its expression along the different stages of fungus development. The bacterial gene transcripts showed the highest values when the fungus was associated to the plant, and peaked in the extraradical mycelium. Strigolactones, which are known to stimulate the AM fungal growth, caused a significant transcript increase in the germinated spores in the absence of the plant. The quantitative real-time reverse-transcription polymerase chain reaction data were strengthened by the quantification of the dividing bacteria, which were increasing in number in germinating spores after the strigolactone treatment. The bioactive molecule alone did not cause any change in the number of bacteria after their isolation from the fungus, thus showing that the strigolactone alone cannot confer free-living capacities to the bacterium.
Genome-Wide Analysis of Differentially Expressed Genes During the Early Stages of Tomato Infection by a Potyvirus
Authors: Alfenas-Zerbini Poliane , Maia Ivan G. , Fávaro Regiane D. , Cascardo Julio C. M. , Brommonschenkel Sérgio H. , Zerbini Francisco Murilo
Published: February 2009

Plant responses against pathogens cause up- and downward shifts in gene expression. To identify differentially expressed genes in a plant-virus interaction, susceptible tomato plants were inoculated with the potyvirus Pepper yellow mosaic virus (PepYMV) and a subtractive library was constructed from inoculated leaves at 72 h after inoculation. Several genes were identified as upregulated, including genes involved in plant defense responses (e.g., pathogenesis-related protein 5), regulation of the cell cycle (e.g., cytokinin-repressed proteins), signal transduction (e.g., CAX-interacting protein 4, SNF1 kinase), transcriptional regulators (e.g., WRKY and SCARECROW transcription factors), stress response proteins (e.g., Hsp90, DNA-J, 20S proteasome alpha subunit B, translationally controlled tumor protein), ubiquitins (e.g., polyubiquitin, ubiquitin activating enzyme 2), among others. Downregulated genes were also identified, which likewise display identity with genes involved in several metabolic pathways. Differential expression of selected genes was validated by macroarray analysis and quantitative real-time polymerase chain reaction. The possible roles played by some of these genes in the viral infection cycle are discussed.
A New ‘Candidatus Liberibacter’ Species Associated with Diseases of Solanaceous Crops
Authors: Liefting Lia W. , Sutherland Paul W. , Ward Lisa I. , Paice Kerry L. , Weir Bevan S. , Clover Gerard R. G.
Published: February 2009

A new disease of glasshouse-grown tomato and pepper in New Zealand has resulted in plant decline and yield loss. Affected plants are characterized by spiky, chlorotic apical growth, curling or cupping of the leaves, and overall stunting. Transmission electron microscopy revealed the presence of phloem-limited bacterium-like organisms in symptomatic plants. The strategy used to identify the bacterium involved using specific prokaryote polymerase chain reaction (PCR) primers in combination with universal 16S rRNA primers. Sequence analysis of the 16S rRNA gene, the 16S/23S rRNA spacer region, and the rplKAJL-rpoBC operon revealed that the bacterium shared high identity with ‘Candidatus Liberibacter’ species. Phylogenetic analysis showed that the bacterium is distinct from the three citrus liberibacter species previously described and has been named ‘Candidatus Liberibacter solanacearum’. This is the first report of a liberibacter naturally infecting a host outside the Rutaceae family. A specific PCR primer pair was developed for its detection.
Liberibacters Associated with Citrus Huanglongbing in Brazil: ‘Candidatus Liberibacter asiaticus’ Is Heat Tolerant, ‘Ca. L. americanus’ Is Heat Sensitive
Authors: Lopes S. A. , Frare G. F. , Bertolini E. , Cambra M. , Fernandes N. G. , Ayres A. J. , Marin D. R. , Bové J. M.
Published: February 2009

In São Paulo State, Brazil, ‘Candidatus Liberibacter americanus’ and ‘Candidatus Liberibacter asiaticus’ are associated with huanglongbing (HLB). Affected municipalities occur mainly in the central and southern regions, where the annual number of hours above 30°C is two to five times lower than that in the extreme northern and western regions. The influence of temperature on sweet orange trees infected with ‘Ca. L. asiaticus’ or ‘Ca. L. americanus’ was studied in temperature-controlled growth chambers. Symptom progression on new shoots of naturally infected and experimentally graft-inoculated symptomatic sweet orange trees was assessed. Mottled leaves developed on all infected trees at 22 to 24°C, but not on any ‘Ca. L. americanus’–infected trees at 27 to 32°C. Quantitative, real time-PCR was used to determine the liberibacter titers in the trees. After 90 days, ‘Ca. L. asiaticus’–infected trees had high titers at 32 and 35°C, but not at 38°C, while ‘Ca. L. americanus’–infected trees had high titers at 24°C, but at 32°C the titers were very low or the liberibacters could not be detected. Thus, the multiplication of ‘Ca. L. asiaticus’ is not yet affected at 35°C, while a temperature of 32°C is detrimental to ‘Ca. L. americanus’. Thus, ‘Ca. L. americanus’ is less heat tolerant than ‘Ca. L. asiaticus’. The uneven distribution of these two liberibacters in São Paulo State might be in relation with these results.
First Report of the Mistletoe Tristerix verticillatus on Schinus fasciculatus from the Sierra de San Luis, Argentina
Authors: Amico G. C. , Nickrent D. L.
Published: February 2009

There are 11 species of mistletoes in the genus Tristerix (Loranthaceae) endemic to the Andes in South America (1,2). Tristerix verticillatus (Ruiz & Pav.) Barlow & Wiens is distributed on the east side of the Andes from Bolivia to Argentina at high elevations (>1,500 m). On the west side of the Andes, it is only found in Chile where it occurs at low to high elevations (50 to 3,000 m). Along its range, the mistletoe parasitizes more than 25 species, mainly Anarcadiaceae and Rhamnaceae. In February of 2007, it was observed to be parasitizing Schinus fasciculatus (Griseb.) I.M. Johnst. (Anacardiaceae) at two locations in the Sierra de San Luis, Argentina. One location was 6 km south of Las Chacras on Route 31 (32°35′56″S, 65°47′6″W, elevation 1,185 m) and the other was 12 km north of El Trapiche on Route 9 (33°1′21″S, 66°4′11″W, elevation 1,260 m). At these localities, the mistletoe was in full flower and parasitized only one host species, S. fasciculatus. No mortality associated with infection by this mistletoe was observed at either location. Specimens of the mistletoe were collected from both locations and deposited at the Centro Regional Universitario Bariloche Herbarium (BCRU), Río Negro, Argentina. To our knowledge, this is the first report of a Tristerix sp. outside the Andes and extends the eastern distribution of the genus by ≈270 km and also of S. fasciculatus serving as a host for T. verticillatus since previous collections were from other species of Schinus.

References: (1) G. C. Amico et al. Am. J. Bot. 94:558, 2007. (2) J. Kuijt, Syst. Bot. Monogr. 19, 1988.
First Report of Powdery Mildew Caused by Erysiphe pulchra on Cornus florida in Italy
Authors: Garibaldi A. , Bertetti D. , Gullino M. L.
Published: February 2009

Cornus florida L. (Cornaceae), flowering dogwood, is a small deciduous tree whose showy inflorescences, clusters of bright red fruits and red and purple leaves in autumn, make it a much appreciated ornamental. During the summer of 2008, severe outbreaks of a previously unknown powdery mildew were observed in several gardens and nurseries in Piedmont (northern Italy). Young leaves were covered with dense, white mycelia and conidia, especially on the adaxial surface. As the disease progressed, infected leaves turned red. Conidia were hyaline, elliptical, borne singly, and measured 32 to 46 × 15 to 20 (average 38 × 17) μm. Conidiophores measured 68 to 77 × 8 to 9 (average 73 × 8) μm, with a cylindrical foot cell measuring 26 to 37 × 8 to 10 (average 31 × 9) μm, followed by two shorter cells. Fibrosin bodies were absent. No chasmothecia were observed. The ITS region (internal transcribed spacer) of rDNA was amplified using primers ITS4/ITS6 and sequenced. The 627-bp sequence (Accession No. EU FJ436989 in GenBank) has 99% identity with Erysiphe pulchra. As proof of pathogenicity, diseased leaves were pressed against leaves of three healthy 3-year-old plants. Three noninoculated plants served as controls. Inoculated and noninoculated plants were maintained outdoors at 13 to 21°C. After 15 days, typical powdery mildew colonies developed on inoculated plants. Noninoculated plants did not show symptoms. The pathogenicity test was carried out twice. To our knowledge, this is the first report of the presence of powdery mildew on C. florida caused by E. pulchra in Italy. Powdery mildew of dogwood, caused by Microsphaera (Erysiphe) pulchra, has been reported in the United States (3) and Japan (1). In Italy, a powdery mildew caused by an Oidium sp. has been reported on C. sanguinea (2). Herbarium specimens of this disease are available at AGROINNOVA Collection, University of Torino, Italy.

References: (1) T. Kobayashi. Index of Fungi Inhabiting Woody Plants in Japan. Host, Distribution, and Literature. Zenkoku-Noson-Kyoikai Publishing Co., Ltd., Tokyo, 2007. (2) G. Sicoli et al. Inf. Agrario 56/48:84, 2000. (3) V. L. Smith. Plant Dis. 83:782, 1999.
Small Subunit rDNA-Based Phylogeny of the Tylenchida Sheds Light on Relationships Among Some High-Impact Plant-Parasitic Nematodes and the Evolution of Plant Feeding
Authors: Holterman M. , Karssen G. , van den Elsen S. , van Megen H. , Bakker J. , Helder J.
Published: February 2009

Cyst (Heteroderidae), root knot (Meloidogyne spp.), and lesion (Pratylenchus spp.) nematodes all belong to a single nematode order, Tylenchida. However, the relationships between and within these economically highly relevant groups, and their relatedness to other parasitic Tylenchida is unclear. We constructed a phylogeny of 116 Tylenchida taxa based on full length small subunit ribosomal DNA (small subunit [SSU] rDNA) sequences. Ancestral state reconstruction points at a gradual development of simple to more complex forms of plant parasitism. Good resolution was observed in distal clades that include cyst, root knot, and lesion nematodes, and monophyly of most families was confirmed. Our data suggest that root knot nematodes have evolved from an ancestral member of the genus Pratylenchus, but it remains unclear which species is closest to this branching point. Contrary to the notoriously polyphagous distal representatives, basal members of the genus Meloidogyne (and probably, their common ancestor) have narrow host ranges. Our analysis also shows that mitotic parthenogeny has arisen at least two times independently among root knot nematodes. In many cases resolution till species was observed, suggesting that SSU rDNA sequences have a potential for DNA barcode-based species identification with, due to the overall conserved nature of this gene, limited intra-species variation.
Graft Transmission Efficiencies and Multiplication of ‘Candidatus Liberibacter americanus’ and ‘Ca. Liberibacter asiaticus’ in Citrus Plants
Authors: Lopes S. A. , Bertolini E. , Frare G. F. , Martins E. C. , Wulff N. A. , Teixeira D. C. , Fernandes N. G. , Cambra M.
Published: February 2009

In Brazil ‘Candidatus Liberibacter asiaticus’ and ‘Ca. L. americanus’ cause huanglongbing (also known as greening), the most destructive citrus disease. A shift in pathogen prevalence was observed over time, with a disproportional increase in ‘Ca. L. asiaticus’ occurrence. Graft transmission experiments were used for a comparative study of both species using budsticks from symptomatic branches of field-affected trees as inoculum. The plants were inoculated with ‘Ca. L. asiaticus’ or ‘Ca. L. americanus’ alone, or simultaneously with both species. Symptom manifestation and conventional and quantitative real-time polymerase chain reaction were used for plant evaluations. ‘Ca. L. americanus’ was detected mainly in symptomatic plants and ‘Ca. L. asiaticus’ was detected in symptomatic plants as well as in infected plants prior to symptom manifestation. Transmission percentages varied from 54.7 to 88.0% for ‘Ca. L. asiaticus’ and 10.0 to 45.2% for ‘Ca. L. americanus’ in two experiments. In co-inoculated plants, 12.9% contained ‘Ca. L. americanus’ only, 40.3% contained ‘Ca. L. asiaticus’ only, and 19.3% contained both species. Average bacterial titers for ‘Ca. L. asiaticus’ and ‘Ca. L. americanus’, in log cells per gram of leaf midrib, were 6.42 and 4.87 for the experimental plants and 6.67 and 5.74 for the field trees used as the source of inoculum. The higher bacterial populations of the ‘Ca. L. asiaticus’-infected plants provided an explanation for the disproportional increase in field prevalence of this species over time, based on the greater likelihood for pathogen transmission by the insect vector.
Transcriptional regulation and stabilization of left–right neuronal identity in C. elegans
Authors: Lesch Bluma J. , Gehrke Andrew R. , Bulyk Martha L. , Bargmann Cornelia I.
Published: February 2009

At discrete points in development, transient signals are transformed into long-lasting cell fates. For example, the asymmetric identities of two Caenorhabditis elegans olfactory neurons called AWCON and AWCOFF are specified by an embryonic signaling pathway, but maintained throughout the life of an animal. Here we show that the DNA-binding protein NSY-7 acts to convert a transient, partially differentiated state into a stable AWCON identity. Expression of an AWCON marker is initiated in nsy-7 loss-of-function mutants, but subsequently lost, so that most adult animals have two AWCOFF neurons and no AWCON neurons. nsy-7 encodes a protein with distant similarity to a homeodomain. It is expressed in AWCON, and is an early transcriptional target of the embryonic signaling pathway that specifies AWCON and AWCOFF; its expression anticipates future AWC asymmetry. The NSY-7 protein binds a specific optimal DNA sequence that was identified through a complete biochemical survey of 8-mer DNA sequences. This sequence is present in the promoter of an AWCOFF marker and essential for its asymmetric expression. An 11-base-pair (bp) sequence required for AWCOFF expression has two activities: One region activates expression in both AWCs, and the overlapping NSY-7-binding site inhibits expression in AWCON. Our results suggest that NSY-7 responds to transient embryonic signaling by repressing AWCOFF genes in AWCON, thus acting as a transcriptional selector for a randomly specified neuronal identity.
Apoptosis of macrophages during pulmonary Mycobacterium bovis infection: correlation with intracellular bacillary load and cytokine levels
Authors: Rodrigues Michele F. , Barsante Michele M. , Alves Caio C. S. , Souza Maria A. , Ferreira Ana P. , Amarante‐Mendes Gustavo P. , Teixeira Henrique C.
Published: February 2009

Apoptosis of macrophages infected with pathogenic mycobacteria is an alternative host defence capable of removing the environment supporting bacterial growth. In this work the influence of virulence and bacterial load on apoptosis of alveolar macrophages during the initial phase of infection by Mycobacterium bovis was investigated. BALB/c mice were infected intratracheally with high or low doses of the virulent (ATCC19274) or attenuated (bacillus Calmette–Guérin Moreau) strains of M. bovis. The frequency of macrophage apoptosis, the growth of mycobacteria in macrophages, and the in situ levels of the cytokines tumour necrosis factor‐α (TNF‐α), interleukin‐10 (IL‐10) and IL‐12 and of the anti‐apoptotic protein Bcl‐2 were measured at day 3 and day 7 post‐infection. An increase of macrophage apoptosis was observed after infection with both strains but the virulent strain induced less apoptosis than the attenuated strain. On the 3rd day after infection with the virulent strain macrophage apoptosis was reduced in the high‐dose group, while on the 7th day post‐infection macrophage apoptosis was reduced in the low‐dose group. Inhibition of apoptosis was correlated with increased production of IL‐10, reduced production of TNF‐α and increased production of Bcl‐2. In addition, the production of IL‐12 was reduced at points where the lowest levels of macrophage apoptosis were observed. Our results indicate that virulent mycobacteria are able to modulate macrophage apoptosis to an extent dependent on the intracellular bacterial burden, which benefits its intracellular growth and dissemination to adjacent cells.
Switch from perforin‐expressing to perforin‐deficient CD8+ T cells accounts for two distinct types of effector cytotoxic T lymphocytes in vivo
Authors: Meiraz Avihai , Garber Orit Gal , Harari Shaul , Hassin David , Berke Gideon
Published: February 2009

Although CD8+ cytotoxic T lymphocytes (CTL) exhibit both Fas ligand (FasL) ‐based and perforin‐based lytic activities, the accepted hallmark of a fully active CTL remains its perforin killing machinery. Yet the origin, rationale for possessing both a slow‐acting (FasL) and a fast‐acting (perforin) killing mechanism has remained enigmatic. Here we have investigated perforin expression in CTL directly involved in acute tumour (i.e. leukaemias EL4 and L1210) allograft rejection occurring within the peritoneal cavity. We show that at the height of the immune response, the majority of conjugate‐forming CD8+ CTL express high levels of perforin messenger RNA and protein, and kill essentially via perforin. Later however, coinciding with complete rejection, fully cytocidal CTL emerge which exhibit a stark decrease in perforin and now kill preferentially via constitutively expressed FasL. Although late in emergence, and persistent, these powerful CTL are neither effector‐memory nor memory CTL. This finding has implications for the monitoring of anti‐transplant responses in clinical settings, based on assessing perforin expression in graft infiltrating CD8+ T cells. The results show that as the immune response progresses in vivo, targeted cellular suicide mainly prunes high perforin‐expressing CD8+ cells, resulting in the gradual switch in effector CTL, from mostly perforin‐based to largely Fas/FasL‐based killers. Hence, two kinds of CD8+ CTL have two killing strategies.
Three‐dimensional analysis of occlusal curvature in healthy Japanese young adults
Authors: KAGAYA K. , MINAMI I. , NAKAMURA T. , SATO M. , UENO T. , IGARASHI Y.
Published: February 2009

Summary  Knowledge of the standard value of the occlusal curvature would be helpful when providing oral rehabilitation for patients with or without occlusal derangement. Dentists often use a 4‐inch radii arc as the standard based on Monson spherical theory. However, the validity of application of this theory in Japanese has not yet been verified. The objective of this study was to determine the typical shape of the occlusal curvature in Japanese adults and investigate the relative contribution of each factor to the depth of the curvature, as the initial phase, to prove the validity of determination of occlusal curvature. Seventy‐nine Japanese adults (42 males and 37 females, aged 18 to 37 years) with intact dental arches were recruited, and the occlusal curvature was estimated by calculating the radius and center position of the approximate sphere. Besides, the relative contribution of gender, age, dental arch length and width, overjet, overbite for the radii was calculated. The median radius of the sphere was 110·6 mm, larger than the 4‐inch value advocated by Monson. This indicates the necessity to reconsider the application of the method of occlusal plane analysis in Japanese individuals. Median position of the centre was 64·6 mm anterior to and 68·5 mm above the mid‐point between condyles. Relative contribution of overbite for the radii was 10·9%, the highest amongst the factors. Therefore, a typical shape of the occlusal curvature was observed in Japanese subjects. Overbite is considered as one of the principal factors correlated to the depth of the occlusal curvature.
Co‐regulation of Xanthomonas campestris virulence by quorum sensing and a novel two‐component regulatory system RavS/RavR
Authors: He Ya‐Wen , Boon Calvin , Zhou Lian , Zhang Lian‐Hui
Published: February 2009

Xanthomonas campestris pv. campestris (Xcc) is known to regulate virulence through a quorum‐sensing mechanism. Detection of the quorum‐sensing signal DSF by sensor RpfC leads to activation of the response regulator RpfG, which influences virulence by degrading cyclic‐di‐GMP and by subsequent increasing expression of the global regulator Clp. In this study, we show that mutation of a response regulator RavR containing the GGDEF–EAL domains decreases Xcc virulence factor production. The functionality of RavR is dependent on its EAL domain‐associated cyclic‐di‐GMP phosphodiesterase activity. Deletion of a multidomain sensor gene ravS, which shares the same operon with ravR, results in similar phenotype changes as the ravR mutant. In addition, the sensor mutant phenotypes can be rescued by in trans expression of the response regulator, supporting the notion that RavS and RavR constitute a two‐component regulatory system. Significantly, mutation of either the PAS domain or key residues of RavS implicated in sensing low‐oxygen tension abrogates the sensor activity in virulence regulation. Moreover, similar to the DSF signalling system, RavS/RavR regulates virulence gene expression through the global regulator Clp. These results outline a co‐regulation mechanism that allows Xcc to integrate population density and environmental cues to modulate virulence factor production and adaptation.
12. Comparison of Antisera
Authors: AXELSEN NILS H. , BOCK ELISABETH , Krøll J.
Published: February 2009

Summary. The possibilities for comparison of the antibody content of two antibody samples are reviewed in simple diagrams.
21. Allergens Identified in Crossed Radioimmunoelectrophoresis
Authors: WEEKE BENT , LøWENSTEIN HENNING
Published: February 2009

Summary. A timothy pollen extract was studied in crossed immunoelectrophoresis by means of precipitating antibodies from rabbits. Six precipitates appeared. Addition to the timothy precipitates of serum from patients with allergy to grass pollen caused a binding of IgE to some or all the precipitates. The IgE‐containing precipitates were identified by autoradiography after addition of 125I‐antihuman IgE.
23. Immunization, Isolation of Immunoglobulins, Estimation of Antibody Titre
Authors: HARBOE N. , INGILD AGNETE
Published: February 2009

Summary. High titred monospecific antibodies are obtained in rabbits injecting as little as 25 μg pure antigen per kg body weight. For polyspecific antibodies the dose is increased 10 times. The immunization schedule is described in detail. A procedure is given for the isolation of the immunoglobulins from antiserum by salting out and ion exchange chromatography. Finally antibody titres as measured by 4 different titration methods are compared using anti‐human IgG from rabbits as a model.
Enzyme Characterization in Quantitative Immunoelectrophoresis
Authors: BROGREN C.‐H. , BøG‐HANSEN T. C.
Published: February 2009

Carboxylic ester hydrolases in human serum were identified, characterized, and quantified by means of crossed and rocket immunoelectrophoresis. Two types of esterase were found, arylesterase (EC 3.1.1.2) and cholinesterase (EC 3.1.1.8), exhibiting differences in specificity for several histochemical substrates. α‐naphthyl acetate and β‐naphthyl acetate were used to distinguish between the two enzymes. Arylesterase seemed to interact specifically with aJipoprotein. Quantitation of enzyme protein and correlation with enzyme activity is described. The experiments illustrate general methodological problems concerning immunochemical characterization of enzymes.
Cross‐Reactions between Pseudomonas aeruginosa and Thirty‐Six Other Bacterial Species
Authors: HøIBY N.
Published: February 2009

Cross‐reactions between Pseudomonas aeruginosa and 36 other bacterial species were studied by various quantitative immunoelectrophoretic techniques. A complex Pseudomonas aeruginosa antigen and a corresponding rabbit antiserum were used as a reference system. Ten of the 55 Pseudomonas aeruginosa antigens were cross‐reactive with antigens from as many as 33 other bacterial species, gram‐negative as well as gram‐positive. As judged by absorption of antibodies the degree of cross‐reactivity of each of the 10 Pseudomonas aeruginosa antigens with antigens from other species was found to be 25–100%, depending on the species and the antigen in question. The closest antigenic relationship to Pseudomonas aeruginosa was found in 5 other Pseudomonas species, but members of the Enterobacteriaceae also cross‐reacted fairly extensively with Pseudomonas aeruginosa. One of the cross‐reactive antigens reacted with a normally occurring antibody in sera from rabbits.
Detection of Concanavalin A — Binding Herpes Simplex Virus Type 1 and Type 2 Antigens by Crossed Immuno‐Affinoelectrophoresis
Authors: VESTERGAARD B. F. , BøG‐HANSEN T. C.
Published: February 2009

The presence of four herpes simplex virus (HSV) glycoprotein antigens in cells infected with HSV type 1 and HSV type 2 was demonstrated by the use of crossed immuno‐affinoelectrophoresis with con A.