Results of satellite tagging of Atlantic bluefin tuna, <Emphasis Type="Italic">Thunnus thynnus</Emphasis>, off the coast of Ireland

Pop-up satellite archival tags were attached to six Atlantic bluefin tuna (Thunnus thynnus) off the west coast of Ireland in autumn 2003 and 2004. The satellite tags measured pressure, ambient temperature and light for the term of deployment. Radio pop-up satellite endpoint positions, light and sea surface temperature estimations of geolocation indicate that two fish tagged minutes apart off the coast of County Donegal, migrated to the eastern and western Atlantic Ocean over the following 8 months. The two fish were 5218 km apart at the termination of the experiment. After tagging in September and popping up the following March and April, one fish had traveled to the western Atlantic while the other was located in the waters off the southwest coast of Portugal. A third fish tagged off the coast of County Donegal in October 2004 moved into the Mediterranean Sea and was caught by a fishing vessel southeast of Malta on 11 June 2005. The results link bluefin tuna feeding on European foraging grounds with known eastern breeding regions and western Atlantic waters.     

Rab35 GTPase and cancer: Linking membrane trafficking to tumorigenesis

Rab35 is a small GTPase that is involved in many cellular processes, including membrane trafficking, cell polarity, lipid homeostasis, immunity, phagocytosis and cytokinesis. Recent studies showed that activating mutations confer Rab35 with oncogenic properties. Conversely, downregulation of Rab35 inverts apico‐basal cell polarity and promotes cell migration. Here we review Rab35’s known functions in membrane trafficking and signaling, cell division and cell migration in cancer cells and discuss the importance of Rab35‐dependent membrane trafficking in cancer progression.      

Massive Sorghum Collection Genotyped with SSR Markers to Enhance Use of Global Genetic Resources

Large ex situ collections require approaches for sampling manageable amounts of germplasm for in-depth characterization and use. We present here a large diversity survey in sorghum with 3367 accessions and 41 reference nuclear SSR markers. Of 19 alleles on average per locus, the largest numbers of alleles were concentrated in central and eastern Africa. Cultivated sorghum appeared structured according to geographic regions and race within region. A total of 13 groups of variable size were distinguished. The peripheral groups in western Africa, southern Africa and eastern Asia were the most homogeneous and clearly differentiated. Except for Kafir, there was little correspondence between races and marker-based groups. Bicolor, Caudatum, Durra and Guinea types were each dispersed in three groups or more. Races should therefore better be referred to as morphotypes. Wild and weedy accessions were very diverse and scattered among cultivated samples, reinforcing the idea that large gene-flow exists between the different compartments. Our study provides an entry to global sorghum germplasm collections. Our reference marker kit can serve to aggregate additional studies and enhance international collaboration. We propose a core reference set in order to facilitate integrated phenotyping experiments towards refined functional understanding of sorghum diversity.     

Helicobacter pylori-induced inhibition of vascular endothelial cell functions: a role for VacA-dependent nitric oxide reduction

Epidemiological and clinical studies provide compelling support for a causal relationship between Helicobacter pylori infection and endothelial dysfunction, leading to vascular diseases. However, clear biochemical evidence for this association is limited. In the present study, we have conducted a comprehensive investigation of endothelial injury in bovine aortic endothelial cells (BAECs) induced by H. pylori-conditioned medium (HPCM) prepared from H. pylori 60190 [vacuolating cytotoxin A (Vac(+))]. BAECs were treated with either unconditioned media, HPCM (0-25% vol/vol), or Escherichia coli-conditioned media for 24 h, and cell functions were monitored. Vac(+) HPCM significantly decreased BAEC proliferation, tube formation, and migration (by up to 44%, 65%, and 28%, respectively). Posttreatment, we also observed sporadic zonnula occludens-1 immunolocalization along the cell-cell border, and increased BAEC permeability to FD40 Dextran, indicating barrier reduction. These effects were blocked by 5-nitro-2-(3-phenylpropylamino)benzoic acid (VacA inhibitor) and were not observed with conditioned media prepared from either VacA-deleted H. pylori or E. coli. The cellular mechanism mediating these events was also considered. Vac(+) HPCM (but not Vac(-)) reduced nitric oxide (NO) by >50%, whereas S-nitroso-N-acetylpenicillamine, an NO donor, recovered all Vac(+) HPCM-dependent effects on cell functions. We further demonstrated that laminar shear stress, an endothelial NO synthase/NO stimulus in vivo, could also recover the Vac(+) HPCM-induced decreases in BAEC functions. This study shows, for the first time, a significant proatherogenic effect of H. pylori-secreted factors on a range of vascular endothelial dysfunction markers. Specifically, the VacA-dependent reduction in endothelial NO is indicated in these events. The atheroprotective impact of laminar shear stress in this context is also evident.     

Construction of Chromosome Segment Substitution Lines in Peanut (Arachis hypogaea L.) Using a Wild Synthetic and QTL Mapping for Plant Morphology

Chromosome segment substitution lines (CSSLs) are powerful QTL mapping populations that have been used to elucidate the molecular basis of interesting traits of wild species. Cultivated peanut is an allotetraploid with limited genetic diversity. Capturing the genetic diversity from peanut wild relatives is an important objective in many peanut breeding programs. In this study, we used a marker-assisted backcrossing strategy to produce a population of 122 CSSLs from the cross between the wild synthetic allotetraploid (A. ipaënsis×A. duranensis)^4x and the cultivated Fleur11 variety. The 122 CSSLs offered a broad coverage of the peanut genome, with target wild chromosome segments averaging 39.2 cM in length. As a demonstration of the utility of these lines, four traits were evaluated in a subset of 80 CSSLs. A total of 28 lines showed significant differences from Fleur11. The line×trait significant associations were assigned to 42 QTLs: 14 for plant growth habit, 15 for height of the main stem, 12 for plant spread and one for flower color. Among the 42 QTLs, 37 were assigned to genomic regions and three QTL positions were considered putative. One important finding arising from this QTL analysis is that peanut growth habit is a complex trait that is governed by several QTLs with different effects. The CSSL population developed in this study has proved efficient for deciphering the molecular basis of trait variations and will be useful to the peanut scientific community for future QTL mapping studies.     

Vectors for regulated gene expression in the radioresistant bacterium Deinococcus radiodurans

Deinococcus radiodurans possesses an exceptional capacity to withstand the lethal and mutagenic effects of most form of DNA damage and has received considerable interest for use in both fundamental and applied research. Here we describe vectors that allow regulated expression of Deinococcal genes for functional analysis. The vectors contain the IPTG-regulated Spac system (Pspac promoter and lacI repressor gene), originally designed for Bacillus subtilis, that we have adapted to be functional in D. radiodurans. We show that the Spac system can control the expression of a lacZ reporter gene over two orders of magnitude depending on the inducer concentration and the copy number of the lacI regulatory gene. Furthermore, we demonstrate that the Spac system can be used to regulate the synthesis of a critical repair protein, such as RecA, resulting in a conditional mitomycin-resistant cell phenotype. We have also developed tools for the construction of conditional mutants where the expression of the target gene is regulated by an inducible promoter. The utility of these conditional gene inactivation systems is exemplified by the conditional lethal phenotype of a mutant expressing gyrA from the Pspac promoter.     

Is nebulized saline a placebo in COPD?

Background

Many trials of nebulized therapy have used nebulized saline as a "placebo". However, nebulized isotonic saline is sometimes used to assist sputum expectoration and relieve breathlessness in COPD patients. We designed this study to establish if nebulized saline had a placebo effect or a clinical effect.

Methods

40 patients were studied following hospital admission for exacerbated COPD (mean FEV1 30% predicted). Patients were randomised to single-blind administration of either 4 mls of nebulized isotonic saline using an efficient nebulizer (active group n = 20) or an inefficient nebulizer (placebo group n = 20). Spirometry and subjective breathlessness scores (Modified Likert Scale) were measured before nebulized treatment and 10 minutes after treatment.

Results

There was no significant change in FEV1 after active or placebo nebulized saline treatment. Patients reported a 4% improvement in mean breathlessness score following placebo (Wilcoxon test; p = 0.37) compared with 23% improvement following active nebulized saline (p = 0.0001). 65% of patients given active nebulized saline but only 5% of the placebo group reported that mucus expectoration was easier after the treatment.

Conclusions

This study lends support to the current use of nebulized saline to relieve breathlessness (possibly by facilitating sputum clearance) in COPD patients. Lung function was not affected. Nebulized saline can therefore be used as a placebo in bronchodilator studies involving COPD patients but it cannot be used as a placebo in trials assessing symptom relief.     

Rapid glucocorticoid stimulation and GABAergic inhibition of hippocampal serotonergic response: in vivo dialysis in the lizard anolis carolinensis

Central serotonin (5-HT) is activated during stressful situations and aggressive interactions in a number of species. Glucocorticoids secreted peripherally during stressful events feed back on central systems and may affect 5-HT mediation of stress-induced behavioral events. To test the neuromodulatory effect of stress hormone secretion, serotonin overflow was measured from the hippocampus of the lizard Anolis carolinensis. Microdialysis was used to collect repeated samples from anesthetized lizards, with perfusate measured by HPLC with electrochemical analysis. Following initially high levels of 5-HT, concentrations stabilized to basal levels after approximately 2 h. Intracortical infusion of 200 ng/ml corticosterone evoked transient increases in 5-HT release of approximately 400%. The effect of corticosterone on 5-HT overflow appears to be dose dependent as 20 ng/ml stimulated an increase of 200%, whereas 2 ng/ml stimulated a 50% increase. Administration of 0.1 and 1 ng/ml GABA via the dialysis probe significantly inhibited 5-HT overflow by 20 and 40%, respectively. The duration of GABA inhibition is greater than the stimulatory response for glucocorticoids. Short-lived glucocorticoid stimulation of 5-HT release suggests a possible mechanism for endocrine mediation of continuously changing social behavioral events.