bluuebunny/crossref_metadata_2025 huggingface dataset:
Database mining and transcriptional analysis of genes encoding inulin-modifying enzymes of Aspergillus niger
Authors: Yuan Xiao-Lian , Goosen Coenie , Kools Harrie , van der Maarel Marc J. E. C. , van den Hondel Cees A. M. J. J , Dijkhuizen Lubbert , Ram Arthur F. J.
Published: September 2006

As a soil fungus, Aspergillus niger can metabolize a wide variety of carbon sources, employing sets of enzymes able to degrade plant-derived polysaccharides. In this study the genome sequence of A. niger strain CBS 513.88 was surveyed, to analyse the gene/enzyme network involved in utilization of the plant storage polymer inulin, and of sucrose, the substrate for inulin synthesis in plants. In addition to three known activities, encoded by the genes suc1 (invertase activity; designated sucA), inuE (exo-inulinase activity) and inuA/inuB (endo-inulinase activity), two new putative invertase-like proteins were identified. These two putative proteins lack N-terminal signal sequences and therefore are expected to be intracellular enzymes. One of these two genes, designated sucB, is expressed at a low level, and its expression is up-regulated when A. niger is grown on sucrose- or inulin-containing media. Transcriptional analysis of the genes encoding the sucrose- (sucA) and inulin-hydrolysing enzymes (inuA and inuE) indicated that they are similarly regulated and all strongly induced on sucrose and inulin. Analysis of a ΔcreA mutant strain of A. niger revealed that expression of the extracellular inulinolytic enzymes is under control of the catabolite repressor CreA. Expression of the inulinolytic enzymes was not induced by fructose, not even in the ΔcreA background, indicating that fructose did not act as an inducer. Evidence is provided that sucrose, or a sucrose-derived intermediate, but not fructose, acts as an inducer for the expression of inulinolytic genes in A. niger.
Nutrient regulation of oligopeptide transport in Saccharomyces cerevisiae
Authors: Wiles Amy M. , Cai Houjian , Naider Fred , Becker Jeffrey M.
Published: September 2006

Small peptides (2–5 amino acid residues) are transported into Saccharomyces cerevisiae via two transport systems: PTR (Peptide TRansport) for di-/tripeptides and OPT (OligoPeptide Transport) for oligopeptides of 4–5 amino acids in length. Although regulation of the PTR system has been studied in some detail, neither the regulation of the OPT family nor the environmental conditions under which family members are normally expressed have been well studied in S. cerevisiae. Using a lacZ reporter gene construct fused to 1 kb DNA from upstream of the genes OPT1 and OPT2, which encode the two S. cerevisiae oligopeptide transporters, the relative expression levels of these genes were measured in a variety of environmental conditions. Uptake assays were also conducted to measure functional protein levels at the plasma membrane. It was found that OPT1 was up-regulated in sulfur-free medium, and that Ptr3p and Ssy1p, proteins involved in regulating the di-/tripeptide transporter encoding gene PTR2 via amino acid sensing, were required for OPT1 expression in a sulfur-free environment. In contrast, as measured by response to toxic tetrapeptide and by real-time PCR, OPT1 was not regulated through Cup9p, which is a repressor for PTR2 expression, although Cup9p did repress OPT2 expression. In addition, all of the 20 naturally occurring amino acids, except the sulfur-containing amino acids methionine and cysteine, up-regulated OPT1, with the greatest change in expression observed when cells were grown in sulfur-free medium. These data demonstrate that regulation of the OPT system has both similarities and differences to regulation of the PTR system, allowing the yeast cell to adapt its utilization of small peptides to various environmental conditions.
Stimulation of the λ
p
R promoter by Escherichia coli SeqA protein requires downstream GATC sequences and involves late stages of transcription initiation
Authors: Łyżeń Robert , Wȩgrzyn Grzegorz , Wȩgrzyn Alicja , Szalewska-Pałasz Agnieszka
Published: September 2006

Escherichia coli SeqA protein is a major negative regulator of chromosomal DNA replication acting by sequestration, and thus inactivation, of newly formed oriC regions. However, other activities of this protein have been discovered recently, one of which is regulation of transcription. SeqA has been demonstrated to be a specific transcription factor acting at bacteriophage λ promoters p
I, p
aQ and p
R. While SeqA-mediated stimulation of p
I and p
aQ occurs by facilitating functions of another transcription activator protein, cII, a mechanism for stimulation of p
R remains largely unknown. Here, it has been demonstrated that two GATC sequences, located 82 and 105 bp downstream of the p
R transcription start site, are necessary for this stimulation both in vivo and in vitro. SeqA-mediated activation of p
R was as effective on a linear DNA template as on a supercoiled one, indicating that alterations in DNA topology are not likely to facilitate the SeqA effect. In vitro transcription analysis demonstrated that the most important regulatory effect of SeqA in p
R transcription occurs after open complex formation, namely during promoter clearance. SeqA did not influence the appearance and level of abortive transcripts or the pausing during transcription elongation. Interestingly, SeqA is one of few known prokaryotic transcription factors which bind downstream of the regulated promoter and still act as transcription activators.
Different subcellular locations of secretome components of Gram-positive bacteria
Authors: Buist Girbe , Ridder Anja N. J. A. , Kok Jan , Kuipers Oscar P.
Published: September 2006

Gram-positive bacteria contain different types of secretion systems for the transport of proteins into or across the cytoplasmic membrane. Recent studies on subcellular localization of specific components of these secretion systems and their substrates have shown that they can be present at various locations in the cell. The translocons of the general Sec secretion system in the rod-shaped bacteriumBacillus subtilishave been shown to localize in spirals along the cytoplasmic membrane, whereas the translocons in the coccoidStreptococcus pyogenesare located in a microdomain near the septum. In both bacteria the Sec translocons appear to be located near the sites of cell wall synthesis. The Tat secretion system, which is used for the transport of folded proteins, probably localizes in the cytoplasmic membrane and at the cell poles ofB. subtilis. InLactococcus lactisthe ABC transporter dedicated to the transport of a small antimicrobial peptide is distributed throughout the membrane. Possible mechanisms for maintaining the localization of these secretion machineries involve their interaction with proteins of the cytoskeleton or components of the cell wall synthesis machinery, or the presence of lipid subdomains surrounding the transport systems.
The vesicle transport protein Vac1p is required for virulence of Candida albicans
Authors: Franke Kathrin , Nguyen Monika , Härtl Albert , Dahse Hans-Martin , Vogl Georgia , Würzner Reinhard , Zipfel Peter F. , Künkel Waldemar , Eck Raimund
Published: September 2006

The putative vesicle transport protein Vac1p of the human pathogenic yeastCandida albicansplays an important role in virulence. To determine the cellular functions of Vac1p, a null mutant was generated by sequential disruption of both alleles. Thevac1null mutant strain showed defective endosomal vesicle transport, demonstrating a role of Vac1p in protein transport to the vacuole. Vac1p also contributes to resistance to metal ions, as the null mutant strain was hypersensitive to Cu2+, Zn2+and Ni2+. In addition, the loss of Vac1p affected several virulence factors ofC. albicans. In particular, thevac1null mutant strain showed defective hyphal growth, even when hyphal formation was induced via different pathways. Furthermore, Vac1p affects chlamydospore formation, adherence to human vaginal epithelial cells, and the secretion of aspartyl proteinases (Saps). Avirulence in a mouse model of systemic infection of thevac1null mutant strongly suggests that Vac1p ofC. albicansis essential for pathogenicity. In summary, the Vac1p protein is required for several cellular pathways, in particular those that control virulence and pathogenicity. Consequently, Vac1p is a novel and interesting target for antifungal drugs.
Comparative analysis of two-component signal transduction systems of Bacillus cereus, Bacillus thuringiensis and Bacillus anthracis
Authors: de Been Mark , Francke Christof , Moezelaar Roy , Abee Tjakko , Siezen Roland J.
Published: September 2006

Members of the Bacillus cereus group are ubiquitously present in the environment and can adapt to a wide range of environmental fluctuations. In bacteria, these adaptive responses are generally mediated by two-component signal transduction systems (TCSs), which consist of a histidine kinase (HK) and its cognate response regulator (RR). With the use of in silico techniques, a complete set of HKs and RRs was recovered from eight completely sequenced B. cereus group genomes. By applying a bidirectional best-hits method combined with gene neighbourhood analysis, a footprint of these proteins was made. Around 40 HK-RR gene pairs were detected in each member of the B. cereus group. In addition, each member contained many HK and RR genes not encoded in pairs (‘orphans’). Classification of HKs and RRs based on their enzymic domains together with the analysis of two neighbour-joining trees of these domains revealed putative interaction partners for most of the ‘orphans’. Putative biological functions, including involvement in virulence and host–microbe interactions, were predicted for the B. cereus group HKs and RRs by comparing them with those of B. subtilis and other micro-organisms. Remarkably, B. anthracis appeared to lack specific HKs and RRs and was found to contain many truncated, putatively non-functional, HK and RR genes. It is hypothesized that specialization of B. anthracis as a pathogen could have reduced the range of environmental stimuli to which it is exposed. This may have rendered some of its TCSs obsolete, ultimately resulting in the deletion of some HK and RR genes.
A mannose-sensitive haemagglutinin (MSHA)-like pilus promotes attachment of Pseudoalteromonas tunicata cells to the surface of the green alga Ulva australis
Authors: Dalisay Doralyn S. , Webb Jeremy S. , Scheffel André , Svenson Charles , James Sally , Holmström Carola , Egan Suhelen , Kjelleberg Staffan
Published: September 2006

This study demonstrates that attachment of the marine bacterium Pseudoalteromonas tunicata to the cellulose-containing surface of the green alga Ulva australis is mediated by a mannose-sensitive haemagglutinin (MSHA-like) pilus. We have identified an MSHA pilus biogenesis gene locus in P. tunicata, termed mshI1I2JKLMNEGFBACDOPQ, which shows significant homology, with respect to its genetic characteristics and organization, to the MSHA pilus biogenesis gene locus of Vibrio cholerae. Electron microscopy studies revealed that P. tunicata wild-type cells express flexible pili peritrichously arranged on the cell surface. A P. tunicata mutant (SM5) with a transposon insertion in the mshJ region displayed a non-piliated phenotype. Using SM5, it has been demonstrated that the MSHA pilus promotes attachment of P. tunicata wild-type cells in polystyrene microtitre plates, as well as to microcrystalline cellulose and to the living surface of U. australis. P. tunicata also demonstrated increased pilus production in response to cellulose and its monomer constituent cellobiose. The MSHA pilus thus functions as a determinant of attachment in P. tunicata, and it is proposed that an understanding of surface sensing mechanisms displayed by P. tunicata will provide insight into specific ecological interactions that occur between this bacterium and higher marine organisms.
Ecophysiology of different filamentous Alphaproteobacteria in industrial wastewater treatment plants
Authors: Kragelund Caroline , Kong Yunhong , van der Waarde Jaap , Thelen Karin , Eikelboom Dick , Tandoi Valter , Thomsen Trine Rolighed , Nielsen Per Halkjær
Published: September 2006

The ecophysiology of five filamentous species affiliated to the Alphaproteobacteria was investigated in industrial activated sludge systems. The five species, ‘Candidatus Alysiosphaera europaea’, ‘Candidatus Monilibacter batavus’, ‘Candidatus Alysiomicrobium bavaricum’, ‘Candidatus Sphaeronema italicum’ and Meganema perideroedes, are very abundant in industrial wastewater treatment plants and are often involved in bulking incidents. The morphology of these filamentous bacterial species resembled Eikelboom's Nostocoida limicola, or Type 021N, and could only be correctly identified by using fluorescence in situ hybridization (FISH), applying species-specific gene probes. Two physiological groupings of the five species were found using microautoradiography combined with FISH. Group 1 (‘Ca. Monilibacter batavus' and ‘Ca. Sphaeronema italicum’) utilized many short-chained fatty acids (acetate, pyruvate and propionate), whereas Group 2 (‘Ca. Alysiosphaera europaea’, ‘Ca. Alysiomicrobium bavaricum’ and Meganema perideroedes) could also exploit several sugars, amino acids and ethanol. All species had polyhydroxyalkanoate granules present and several of the species had a very large storage capacity. No activity was found under strict anaerobic conditions, while uptake of substrate was observed in the presence of nitrate or nitrite as potential electron acceptor. However, for all species a reduced number of substrates could be consumed under these conditions compared to aerobic conditions. Only a little exo-enzymic activity was found and nearly all species had a hydrophobic cell surface. Based on knowledge of the ecophysiological potential, control strategies are suggested.
Evolution of advertisement signals in North American hylid frogs: vocalizations as end‐products of calling behavior
Authors: Robillard Tony , Höbel Gerlinde , Carl Gerhardt H.
Published: September 2006

We studied the advertisement signals in two clades of North American hylid frogs in order to characterize the relationships between signal acoustic structure and underlying behavior. A mismatch was found between the acoustic structure and the mechanism of sound production. Two separate sets of phylogenetic characters were coded following acoustic versus mechanistic criteria, and exploratory treatments were made to compare their respective phylogenetic content in comparison with the molecular phylogeny (Faivovich et al., 2005). We discuss the consequences of the acoustic/mechanistic mismatch in terms of significance of acoustic characters for phylogenetic and comparative studies; and the evolution of vocalizations in North American treefrogs. Considering only the acoustic structure of frog vocalizations can lead to misleading results in terms of both phylogenetic signal and evolution of vocalizations. In contrast, interpreting the acoustic signals with regard to the mechanism of sound production results in consistent phylogenetic information. The mechanistic coding also provides strong homologies for use in comparative studies of frog vocalizations, and to derive and test evolutionary hypotheses.

© The Willi Hennig Society 2005.
Alterations of NADPH:protochlorophyllide oxidoreductase quantity and lipid composition in etiolated barley seedlings infected by Barley stripe mosaic virus (BSMV)
Authors: HARSÁNYI ANETT , RYBERG MARGARETA , ANDERSSON MATS X. , BÓKA KÁROLY , LÁSZLÓ LAJOS , BOTOND GERGELY , BÖDDI BÉLA , GÁBORJÁNYI RICHARD
Published: September 2006

To understand the phenomenon by which infection of seed‐transmitted Barley stripe mosaic virus (BSMV) alters membrane structures and inhibits protochlorophyllide biosynthesis of dark‐grown barley (Hordeum vulgare L.) plants, we analysed the presence of NADPH:protochlorophyllide oxidoreductase (POR, EC 1.3.1.33) and the galactolipid content and fatty acid composition. The amount of POR in etioplasts of infected leaves, compared with non‐infected leaves, was reduced, as measured by immunoelectron microscopy and Western blot. These results are in agreement with the previously described reduction of the ratio of the photoactive 650 nm to non‐photoactive 630 nm absorbing protochlorophyllide forms (Harsányi et al., 2002. Physiol. Plant 114, 149–155). The galactolipid content was lower in infected leaves. Monogalactosyl‐diacylglycerol (MGDG) content was reduced to 40% and digalactosyl‐diacylglycerol to 55% of control plants on a fresh weight basis. In infected plants, the proportion of linolenic acid decreased in both galactolipids. The lower amount of highly unsaturated fatty acids and the reduced abundance of MGDG correlated well with the previously detected reduction in the membrane ratio of prolamellar body (PLB) to prothylakoid (Harsányi et al., 2002. Physiol. Plant 114, 149–155). The reduced amount of POR and the above described alterations in the lipid composition resulted in a disturbed structure of PLBs. As a consequence, pigment synthesis and the greening process were inhibited in infected cells, in turn explaining the appearance of chlorotic stripes of BSMV‐infected barley leaves. Our results show that BSMV infection can be detected at a very early stage of leaf development.
The highly attenuated vaccinia virus strain modified virus Ankara induces apoptosis in melanoma cells and allows bystander dendritic cells to generate a potent anti-tumoral immunity
Authors: Greiner S , Humrich J Y , Thuman P , Sauter B , Schuler G , Jenne L
Published: September 2006

Vaccinia virus (VV) has been tested as oncolytic virus against malignant melanoma in clinical trials for more than 40 years. Until now, mainly strains comparable to viral strains used for smallpox vaccination have been probed for anti-tumoral therapy. We have shown recently that the wild-type strain Western Reserve (WR) can interfere with crucial functions of monocyte-derived dendritic cells (DCs). Our aim was to examine whether viral immune evasion mechanisms might be responsible for the ineffectiveness of WR-based vaccination strategies and whether the highly attenuated strain modified virus Ankara (MVA) differs from WR with respect to its possible immunostimulatory capacity after intratumoral injection. Using in vitro experiments, we compared the effect of both strains on melanoma cells and on local bystander DCs. We found that both VV-strains infected melanoma cells efficiently and caused disintegration of the actin cytoskeleton, as shown by fluorescence microscopy. In addition, both VV-strains caused apoptotic cell death in melanoma cells after infection. In contrast to MVA, WR underwent a complete viral replication cycle in melanoma cells. Bystander DCs were consecutively infected by newly generated WR virions and lost their capacity to induce allogeneic T cell proliferation. DCs in contact with MVA-infected melanoma cells retained their capacity to induce T cell proliferation. Immature DCs were capable of phagocytosing MVA-infected melanoma cells. Priming of autologous CD8+ T cells by DCs that had phagocytosed MVA-infected, MelanA positive melanoma cells resulted in the induction of T cell clones specifically reactive against the model antigen MelanA as shown by enzyme-linked immunospot (ELISPOT) analysis. We conclude that the clinical trials with oncolytic wild-type VV failed probably because of suppression of bystander DCs and consecutive suppression of T cell-mediated anti-melanoma immunity. The attenuated VV-strain MVA facilitates the generation of tumour associated antigen (TAA)-specific T cell response as it is oncolytic for melanoma cells, but non-toxic for DC, and should be a promising candidate for intralesional metastatic melanoma therapy.
Proviral load and immune markers associated with human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in Peru
Authors: Best I , Adaui V , Verdonck K , González E , Tipismana M , Clark D , Gotuzzo E , Vanham G
Published: September 2006

Human T-lymphotropic virus type 1 (HTLV-1) is the aetiological agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The objective of this study is to identify which ex vivo and in vivo markers are associated independently with HAM/TSP in a Peruvian population. Eighty-one subjects (33 men/48 women) were enrolled: 35 presented with HAM/TSP, 33 were asymptomatic HTLV-1 carriers (ACs) and 13 were HTLV-1-seronegative controls (SCs). Ex vivo markers included T cell proliferation and Th1 [interferon (IFN)-γ], Th2 [interleukin (IL)-4, IL-5], proinflammatory [tumour necrosis factor (TNF)-α] and anti-inflammatory (IL-10) cytokine production in non-stimulated peripheral blood mononuclear cell (PBMC) cultures. In vivo CD4+ T cell count, markers of Th1 [interferon-inducible protein (IP)-10] and Th2 (sCD30) activity in plasma and HTLV-1 proviral load in PBMCs were also evaluated. In univariate analysis, several markers, including T cell proliferation, IFN-γ, IP-10, sCD30 and proviral load were associated with HAM/TSP, but in a multiple logistic regression analysis only the proviral load remained associated significantly with disease manifestation [adjusted OR 9·10 (1·24–66·91)]. Our findings suggest that HAM/TSP is associated primarily with proviral load, whereas the observed association with some immune markers seems secondary.
The T cell response to persistent herpes virus infections in common variable immunodeficiency
Authors: Raeiszadeh M , Kopycinski J , Paston S J , Diss T , Lowdell M , Hardy G A D , Hislop A D , Workman S , Dodi A , Emery V , Webster A D
Published: September 2006

We show that at least half of patients with common variable immunodeficiency (CVID) have circulating CD8+ T cells specific for epitopes derived from cytomegalovirus (CMV) and/or the Epstein–Barr virus (EBV). Compared to healthy age-matched subjects, more CD8+ T cells in CVID patients were committed to CMV. Despite previous reports of defects in antigen presentation and cellular immunity in CVID, specific CD4+ and CD8+ T cells produced interferon (IFN)-γ after stimulation with CMV peptides, and peripheral blood mononuclear cells secreted perforin in response to these antigens. In CVID patients we found an association between a high percentage of circulating CD8+ CD57+ T cells containing perforin, CMV infection and a low CD4/CD8 ratio, suggesting that CMV may have a major role in the T cell abnormalities described previously in this disease. We also show preliminary evidence that CMV contributes to the previously unexplained severe enteropathy that occurs in about 5% of patients.
Immune markers measured before treatment predict outcome of intensive phase tuberculosis therapy
Authors: Brahmbhatt S , Black G F , Carroll N M , Beyers N , Salker F , Kidd M , Lukey P T , Duncan K , Van Helden P , Walzl G
Published: September 2006

The development of a statistical model based on simple immunological markers which could predict the response to tuberculosis treatment would facilitate clinical trials of new anti-tuberculosis drugs. We have examined the ability of immunological biomarkers, measured at diagnosis and after 4 weeks of treatment, to predict sputum smear status at week 8. Eighteen tuberculosis patients with positive Ziehl–Nielsen (ZN)-stained sputum smears 8 weeks after initiation of treatment (slow response) were matched for age, gender, sputum smear grade and extent of disease on chest radiograph to 18 patients with negative sputum smears at week 8 (fast response). In addition to total white blood cell (WBC) counts and absolute lymphocyte, monocyte and neutrophil numbers, concentrations of six serum markers were measured by enzyme-linked immunosorbent assay (ELISA) in all patients (soluble interleukin-2 receptor alpha (sIL-2Rα), granzyme B, soluble tumour necrosis factor alpha receptors 1 and 2 (sTNF-R1 and -2), nitrotyrosine and interferon-gamma (IFN-γ). At diagnosis, 4 biomarkers (sTNF-R1, total WBC, absolute monocyte and absolute neutrophil numbers) were significantly higher in slow response patients. At week 4, total WBC count and absolute monocyte and neutrophil numbers remained significantly higher in slow responders. Discriminant analysis of the diagnosis and week 4 data provided models for classification of slow response patients with 67% and 83% predictive accuracy. We suggest that treatment response phenotypes can be determined before the start of treatment. Reliable predictive models would allow targeted interventions for patients at risk for slow treatment response to standard tuberculosis therapy.
Fire, fuels and restoration of ponderosa pine–Douglas fir forests in the Rocky Mountains, USA
Authors: Baker William L. , Veblen Thomas T. , Sherriff Rosemary L.
Published: September 2006

Aim Forest restoration in ponderosa pine and mixed ponderosa pine–Douglas fir forests in the US Rocky Mountains has been highly influenced by a historical model of frequent, low‐severity surface fires developed for the ponderosa pine forests of the Southwestern USA. A restoration model, based on this low‐severity fire model, focuses on thinning and prescribed burning to restore historical forest structure. However, in the US Rocky Mountains, research on fire history and forest structure, and early historical reports, suggest the low‐severity model may only apply in limited geographical areas. The aim of this article is to elaborate a new variable‐severity fire model and evaluate the applicability of this model, along with the low‐severity model, for the ponderosa pine–Douglas fir forests of the Rocky Mountains.

Location Rocky Mountains, USA.

Methods The geographical applicability of the two fire models is evaluated using historical records, fire histories and forest age‐structure analyses.

Results Historical sources and tree‐ring reconstructions document that, near or beforead1900, the low‐severity model may apply in dry, low‐elevation settings, but that fires naturally varied in severity in most of these forests. Low‐severity fires were common, but high‐severity fires also burned thousands of hectares. Tree regeneration increased after these high‐severity fires, and often attained densities much greater than those reconstructed for Southwestern ponderosa pine forests.

Main conclusions Exclusion of fire has not clearly and uniformly increased fuels or shifted the fire type from low‐ to high‐severity fires. However, logging and livestock grazing have increased tree densities and risk of high‐severity fires in some areas. Restoration is likely to be most effective which seeks to (1) restore variability of fire, (2) reverse changes brought about by livestock grazing and logging, and (3) modify these land uses so that degradation is not repeated.
ORIGINAL ARTICLE: Predicting species distributions from small numbers of occurrence records: a test case using cryptic geckos in Madagascar
Authors: Pearson Richard G. , Raxworthy Christopher J. , Nakamura Miguel , Townsend Peterson A.
Published: September 2006

Aim  Techniques that predict species potential distributions by combining observed occurrence records with environmental variables show much potential for application across a range of biogeographical analyses. Some of the most promising applications relate to species for which occurrence records are scarce, due to cryptic habits, locally restricted distributions or low sampling effort. However, the minimum sample sizes required to yield useful predictions remain difficult to determine. Here we developed and tested a novel jackknife validation approach to assess the ability to predict species occurrence when fewer than 25 occurrence records are available.

Location  Madagascar.

Methods  Models were developed and evaluated for 13 species of secretive leaf‐tailed geckos (Uroplatus spp.) that are endemic to Madagascar, for which available sample sizes range from 4 to 23 occurrence localities (at 1 km2 grid resolution). Predictions were based on 20 environmental data layers and were generated using two modelling approaches: a method based on the principle of maximum entropy (Maxent) and a genetic algorithm (GARP).

Results  We found high success rates and statistical significance in jackknife tests with sample sizes as low as five when the Maxent model was applied. Results for GARP at very low sample sizes (less than c. 10) were less good. When sample sizes were experimentally reduced for those species with the most records, variability among predictions using different combinations of localities demonstrated that models were greatly influenced by exactly which observations were included.

Main conclusions  We emphasize that models developed using this approach with small sample sizes should be interpreted as identifying regions that have similar environmental conditions to where the species is known to occur, and not as predicting actual limits to the range of a species. The jackknife validation approach proposed here enables assessment of the predictive ability of models built using very small sample sizes, although use of this test with larger sample sizes may lead to overoptimistic estimates of predictive power. Our analyses demonstrate that geographical predictions developed from small numbers of occurrence records may be of great value, for example in targeting field surveys to accelerate the discovery of unknown populations and species.
A pilot study of quantitative assessment of mandible advancement using pressure–flow relationship during midazolam sedation
Authors: AYUSE T. , HOSHINO Y. , INAZAWA T. , OI K. , SCHNEIDER H. , SCHWARTZ A. R.
Published: September 2006

summary  It has been proposed that a titration of the mandibular positioner would be a promising method for predicting the outcome of nasal continuous positive airway pressure (CPAP) therapy. This study was carried out to test the hypothesis that mandible advancement could be evaluated by analysis of inspiratory flow limitation using a titration procedure. To explore its effect, we examined upper airway pressure–flow relationships using a titrated mandible positioner during midazolam sedation. Non‐flow limited inspiration occurred when the mandible was advanced 7·1 ± 1·2 mm from centric occlusion position. In the centric occlusion position (0 mm advancement), Pcrit was −1·9 ± 2·9 cmH2O and Rua was 23·3 ± 4·5 cmH2O L−1 s−1. In the eMAP position, Pcrit was −7·3 ± 1·9 cmH2O and Rua was 27·8 ± 3·3 cmH2O L−1 s−1. Essentially no CPAP was required to overcome flow limitation in eMAP position, whereas 3·7 ± 2·2 cmH2O CPAP was required in centric occlusion position. We conclude that assessing inspiratory flow limitation using a titrated mandible positioner was effective for estimating individual‐matched mandible positions.
Dental attrition models predicting temporomandibular joint disease or masticatory muscle pain versus asymptomatic controls
Authors: SELIGMAN D. A. , PULLINGER A. G.
Published: September 2006

summary  Aims:  To determine whether patients with temporomandibular joint disease or masticatory muscle pain can be usefully differentiated from asymptomatic controls using multifactorial classification tree models of attrition severity and/or rates.

Methods:  Measures of attrition severity and rates in patients diagnosed with disc displacement (n = 52), osteoarthrosis (n = 74), or masticatory muscle pain only (n = 43) were compared against those in asymptomatic controls (n = 132). Cross‐validated classification tree models were tested for fit with sensitivity, specificity, accuracy and log likelihood accountability.

Results:  The model for identifying asymptomatic controls only required the three measures of attrition severity (anterior, mediotrusive and laterotrusive posterior) to be differentiated from the patients with a 74·2 ± 3·8% cross‐validation accuracy. This compared with cross‐validation accuracies of 69·7 ± 3·7% for differentiating disc displacement using anterior and laterotrusive attrition severity, 68·7 ± 3·9% for differentiating disc displacement using anterior and laterotrusive attrition rates, 70·9 ± 3·3% for differentiating osteoarthrosis using anterior attrition severity and rates, 94·6 ± 2·1% for differentiating myofascial pain using mediotrusive and laterotrusive attrition severity, and 92·0 ± 2·1% for differentiating myofascial pain using mediotrusive and anterior attrition rates. The myofascial pain models exceeded the ≥75% sensitivity and ≥90% specificity thresholds recommended for diagnostic tests, and the asymptomatic control model approached these thresholds.

Conclusion:  Multifactorial models using attrition severity and rates may differentiate masticatory muscle pain patients from asymptomatic controls, and have some predictive value for differentiating intracapsular temporomandibular disorder patients as well.
Regulation of cytotoxin expression by converging eukaryotic‐type and two‐component signalling mechanisms in Streptococcus agalactiae
Authors: Rajagopal Lakshmi , Vo Anthony , Silvestroni Aurelio , Rubens Craig E.
Published: September 2006

Signal transducing mechanisms are essential for regulation of gene expression in both prokaryotic and eukaryotic organisms. Regulation of gene expression in eukaryotes is accomplished by serine/threonine and tyrosine kinases and cognate phosphatases. In contrast, gene expression in prokaryotes is controlled by two‐component systems that comprise a sensor histidine kinase and a cognate DNA binding response regulator. Pathogenic bacteria utilize two‐component systems to regulate expression of their virulence factors and for adaptive responses to the external environment. We have previously shown that the human pathogen Streptococcus agalactiae (Group B Streptococci, GBS) encodes a single eukaryotic‐type serine/threonine kinase Stk1, which is important for virulence of the organism. In this study, we aimed to understand how Stk1 contributes to virulence of GBS. Our results indicate that Stk1 expression is important for resistance of GBS to human blood, neutrophils and oxidative stress. Consistent with these observations, Stk1 positively regulates transcription of a cytotoxin, β‐haemolysin/cytolysin (β‐H/C) that is critical for survival of GBS in the bloodstream and for resistance to oxidative stress. Interestingly, positive regulation of β‐H/C by Stk1 requires the two‐component regulator CovR. Further, we show that Stk1 can negatively regulate transcription of CAMP factor in a CovR‐dependent manner. As Stk1 phosphorylates CovR in vitro, these data suggest that serine/threonine phosphorylation impacts CovR‐mediated regulation of GBS gene expression. In summary, our studies provide novel information that a eukaryotic‐type serine/threonine kinase regulates two‐component‐mediated expression of GBS cytotoxins.
Characterization of CidR‐mediated regulation in Bacillus anthracis reveals a previously undetected role of S‐layer proteins as murein hydrolases
Authors: Ahn Jong‐Sam , Chandramohan Lakshmi , Liou Linda E. , Bayles Kenneth W.
Published: September 2006

Recent studies have shown that the Staphylococcus aureus cidABC and lrgAB operons are involved in the regulation of cell death and lysis. The transcription of cidABC and lrgAB was shown to be induced by acetic acid and was dependent on the cidR gene encoding a new member of the LysR‐type transcription regulator (LTTR) family of proteins. In the study presented here, we examined the phenotypic and regulatory effects of disrupting a cidR homologue in Bacillus anthracis. As in S. aureus, the cidR mutation affected expression of the B. anthracis cid and lrg homologues, murein hydrolase activity and cell viability in stationary phase. Interestingly, the predominant murein hydrolase affected was an 85 kDa protein that was identified as Sap, a primary constituent of the S‐layer in B. anthracis. The ability of Sap, as well as its counterpart EA1, to exhibit murein hydrolase activity was confirmed by cloning their respective genes in Escherichia coli and showing that the overexpressed proteins contained this activity. Northern blot analyses revealed that the cidR mutation caused reduced transcription of the genes encoding Sap and EA1, as well as CsaB involved in the attachment of the S‐layer proteins to the cell wall. The results of these studies not only establish the existence of the cid and lrg murein hydrolase regulatory network in B. anthracis, but also help to define the function and regulation of the S‐layer proteins.
Thellungiella halophila, a salt‐tolerant relative of Arabidopsis thaliana, has specific root ion‐channel features supporting K+/Na+ homeostasis under salinity stress
Authors: Volkov Vadim , Amtmann Anna
Published: September 2006

Thellungiella halophila is a salt‐tolerant relative of Arabidopsis thaliana with high genetic and morphological similarity. In a saline environment, T. halophila accumulates less sodium and retains more potassium than A. thaliana. Detailed electrophysiological comparison of ion currents in roots of both species showed that, unlike A. thaliana, T. halophila exhibits high potassium/sodium selectivity of the instantaneous current. This current differs in its pharmacological profile from the current through inward‐ and outward‐rectifying K+ channels insofar as it is insensitive to Cs+ and TEA+, but resembles voltage‐independent channels of glycophytes as it is inhibited by external Ca2+. Addition of Cs+ and TEA+ to the growth medium confirmed the key role of the instantaneous current in whole‐plant sodium accumulation. A negative shift in the reversal potential of the instantaneous current under high‐salt conditions was essential for decreasing sodium influx to twofold lower than the corresponding value in A. thaliana. The lower overall sodium permeability of the T. halophila root plasma membrane resulted in a smaller membrane depolarization during salt exposure, thus allowing the cells to maintain their driving force for potassium uptake. Our data provide quantitative evidence that specific features of ion channels lead to superior sodium/potassium homeostasis in a halophyte compared with a closely related glycophyte.
Simultaneous exposure of several allergens has an additive effect on multisensitized basophils
Authors: Nopp A. , Johansson S. G. O. , Lundberg M. , Öman H.
Published: September 2006

Background:  Patients immunoglobulin (Ig)E‐sensitized to more than one allergen in their environment often have more symptoms than mono‐sensitized individuals, which indicates that the allergens may have an additive effect. In order to study if such an effect could be detected on the inflammatory, cellular level, multisensitized basophils were challenged with various dose combinations of two relevant allergens.

Methods:  Basophils from patients IgE‐sensitized to timothy/cat, birch/cat, timothy/mite and cat/mite were challenged with serial dilutions of different combinations of the two allergens. The basophil response was measured as CD63 expression analysed by flow cytometry.

Results:  The doses of each allergen in the pair had an additive effect resulting in a shift of the dose–response curve to higher CD63 percentages and higher CD‐sens.

Conclusions:  If a patient has IgE antibodies and thus sensitized basophils to more than one allergen, to which he is simultaneously exposed, the additive effect should be considered. Even low concentrations of IgE antibodies could be of clinical relevance in such a situation.
Sleep disturbances in allergic diseases
Authors: Baiardini I. , Braido F. , Cauglia S. , Canonica G. W.
Published: September 2006

Sleep is fundamental for physical and mental health as well as daytime performance and represents a crucial aspect in the personal representations of well‐being. Sleep disturbances in patients with chronic disorders constitute a factor that contributes to exacerbate symptoms, complicate management, and affect mood and quality of life (QoL). Allergic diseases are a global health problem of increasing prevalence that affects up to 15% of the population in Western countries. Sleep problems associated with allergic diseases may play a role in worsening the burden of illness, contributing to impairment of the QoL. The aim of this review was to describe the most common causes leading to sleep disturbance in allergic patients and their consequences on the QoL. The possible negative effects of treatment on sleep parameters has been also considered.
Differentiation of chronic sinus diseases by measurement of inflammatory mediators
Authors: Van Zele T. , Claeys S. , Gevaert P. , Van Maele G. , Holtappels G. , Van Cauwenberge P. , Bachert C.
Published: September 2006

Background:  Chronic rhinosinusitis (CRS) clinically is a heterogeneous group of sinus diseases, which may cover different disease entities, or may represent a disease continuum. Studying inflammatory cells and mediators in clearly defined disease subgroups may lead to a better differentiation of chronic sinus diseases.

Methods:  Sinonasal mucosal tissue from 10 nasal polyp (NP) patients, 13 cystic fibrosis patients (CF‐NP), eight CRS subjects without polyps, and nine control patients were stained for CD3, CD25, CD68, CD20, myeloperoxidase (MPO), CD138 and tissue homogenates were assayed for eotaxin, interleukin (IL)‐1β, IL‐2sRα, IL‐5, interferon (IFN)‐γ, IL‐8, transforming growth factor (TGF)‐β1, tumor necrosis factor‐α, and MPO by enzyme‐linked immunosorbent assay or UNICAP system.

Results:  Nasal polyp and CF‐NP showed increased numbers and activation of T cells, while only NP displayed an increase in plasma cells. Nasal polyp had significantly higher levels of eosinophilic markers [eosinophils, eotaxin, and eosinophil cationic protein (ECP)] compared with CRS, controls and CF‐NP. Chronic rhinosinusitis was characterized by a Th1 polarization with high levels of IFN‐γ and TGF‐β, while NP showed a Th2 polarization with high IL‐5 and immunoglobulin (Ig) E concentrations. Nasal polyp and CF‐NP were discriminated by edema from CRS and controls, with CF‐NP displaying a very prominent neutrophilic inflammation.

Conclusion:  Based on cellular and mediator profiles, we suggest that CRS, NP, and CF‐NP are distinct disease entities within the group of chronic sinus diseases.
Swimming pool attendance and hay fever rates later in life
Authors: Kohlhammer Y. , Döring A. , Schäfer T. , Wichmann H.‐E. , Heinrich J. ,   the KORA Study Group
Published: September 2006

Background:  Exposure to chlorination by‐products through swimming pool attendance showed adverse health effects on children. The aim of our study was to assess whether pool attendance in childhood would be related to higher rates of allergic diseases in adulthood, with special regard to hay fever.

Methods:  2606 adults aged 35–74 years provided retrospectively collected information on swimming pool attendance and medical history, including data on atopic diseases. Information was assessed by a combination of a personal interview and a self‐administered questionnaire. Logistic regression models were applied to study associations between hay fever and swimming pool attendance, adjusted for potentially relevant confounders, such as age, gender, region, education and smoking.

Results:  Higher rates of hay fever could be seen when frequently exposed at school age (aOR: 1.74, 95% CI: 1.09–2.77), frequently exposed during the past 12 months (aOR: 1.32, 95% CI: 0.92–1.89) and ever exposed (aOR: 1.65, 95% CI: 0.98–2.78). Strongest associations were found for the youngest subjects and were dose‐related to the extent of current and school‐age pool attendance.

Conclusions:  Impaired integrity of the lung epithelial by exposure to chlorination by‐products might facilitate a closer contact to allergens and therefore could result in higher rates of hay fever.
Tauopathy: An overview
Authors: Iwatsubo Takeshi
Published: September 2006

In this symposium, cutting‐edge data on neuropathology, pathological biochemistry and molecular biology of sporadic and familial tauopathies, as well as on the development of model animals, were presented and discussed by five expert neuropathologists.
Ultrastructural characteristics of tau filaments in tauopathies: Immuno‐electron microscopic demonstration of tau filaments in tauopathies
Authors: Arima Kunimasa
Published: September 2006

The microtubule‐associated protein tau aggregates into filaments in the form of neurofibrillary tangles, neuropil threads and argyrophilic grains in neurons, in the form of variable astrocytic tangles in astrocytes and in the form of coiled bodies and argyrophilic threads in oligodendrocytes. These tau filaments may be classified into two types, straight filaments or tubules with 9–18 nm diameters and “twisted ribbons” composed of two parallel aligned components. In the same disease, the fine structure of tau filaments in glial cells roughly resembles that in neurons. In sporadic tauopathies, individual tau filaments show characteristic sizes, shapes and arrangements, and therefore contribute to neuropathologic differential diagnosis. In frontotemporal dementias caused by tau gene mutations, variable filamentous profiles were observed in association with mutation sites and insoluble tau isoforms, including straight filaments or tubules, paired helical filament‐like filaments, and twisted ribbons. Pre‐embedding immunoelectron microscopic studies were carried out using anti‐3‐repeat tau and anti‐4‐repeat tau specific antibodies, RD3 and RD4. Straight tubules in neuronal and astrocytic Pick bodies were immunolabeled by the anti‐3‐repeat tau antibody. The anti‐4‐repeat tau antibody recognized abnormal tubules comprising neurofibrillary tangles, coiled bodies and argyrophilic threads in progressive supranuclear palsy (PSP) and corticobasal degeneration. In the pre‐embedding immunoelectron microscopic study using the phosphorylated tau AT8 antibody, tuft‐shaped astrocytes of PSP were found to be composed of bundles of abnormal tubules in processes and perikarya of protoplasmic astrocytes. In this study, the 3‐repeat tau or 4‐repeat tau epitope was detected in situ at the ultrastructural level in abnormal tubules in representative pathological lesions in Pick’s disease, PSP and corticobasal degeneration.
Animal models of tauopathies
Authors: Higuchi Makoto , Saido Takaomi C. , Suhara Tetsuya
Published: September 2006

Intracellular fibrillar amyloid lesions comprised of tau proteins are pathological hallmarks in diverse neurodegenerative disorders. As models of these tauopathies, transgenic mice overexpressing tau with or without mutations discovered in familial tauopathies were generated. Findings in these tau transgenic mice support the notion that impairments of tau proteins are causally related to tauopathies, while studies on crossbred mice have indicated initiation and promotion of tau‐positive neuropathologies by cross‐talk among several pathogenic molecules. Enhancement of tau pathology by amyloid β (Aβ) deposition provided some of the most compelling evidence for such a cross‐talk, and molecular processes linking abnormalities of Aβ and tau have been suggested to involve activation of calcium‐dependent protease, calpain, based on analyses of amyloid precursor protein transgenic mice crossbred with other genetically engineered mice with altered calpain activity. It also should be noted that mice transgenic for both tau and α‐synuclein exhibit facilitated polymerization of these molecules into pathological filaments. Roles of fibrillar tau deposits in nervous system injuries can be mechanistically pursued by longitudinal monitoring of brain amyloidosis and neuroglial degeneration in the time course of antiamyloid intervention. The possibility of in vivo detection of tau‐positive amyloid lesions has been demonstrated by intravenous administration of potential tracers into tau transgenic mice and subsequent brain imaging. Moreover, visualization of glial responses in living brains may allow sensitive detection of degenerative changes in the central nervous system.