Adenosine A1/A2a receptor agonist AMP-579 induces acute and delayed preconditioning against in vivo myocardial stunning

The purpose of this study was to determine whether the adenosine A1/A2a receptor agonist AMP-579 induces acute and delayed preconditioning against in vivo myocardial stunning. Regional stunning was produced by 15 min of coronary artery occlusion and 3 h of reperfusion (RP) in anesthetized open-chest pigs. In acute protection studies, animals were pretreated with saline, low-dose AMP-579 (15 microg/kg iv bolus 10 min before ischemia), or high-dose AMP-579 (50 microg/kg iv at 14 microg/kg bolus + 1.2 microg.kg(-1).min(-1) for 30 min before coronary occlusion). The delayed preconditioning effects of AMP-579 were evaluated 24 h after administration of saline vehicle or high-dose AMP-579 (50 microg/kg iv). Load-insensitive contractility was assessed by measuring regional preload recruitable stroke work (PRSW) and PRSW area. Acute preconditioning with AMP-579 dose dependently improved regional PRSW: 129 +/- 5 and 100 +/- 2% in high- and low-dose AMP-579 groups, respectively, and 78 +/- 5% in the control group at 3 h of RP. Administration of the adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (0.7 mg/kg) blocked the acute protective effect of high-dose AMP-579, indicating that these effects are mediated through A1 receptor activation. Delayed preconditioning with AMP-579 significantly increased recovery of PRSW area: 64 +/- 5 vs. 33 +/- 5% in control at 3 h of RP. In isolated perfused rat heart studies, kinetics of the onset and washout of AMP-579 A1 and A2a receptor-mediated effects were distinct compared with those of other adenosine receptor agonists. The unique nature of the adenosine agonist AMP-579 may play a role in its ability to induce delayed preconditioning against in vivo myocardial stunning.     

Vanin-1 pantetheinase drives smooth muscle cell activation in post-arterial injury neointimal hyperplasia

The pantetheinase vanin-1 generates cysteamine, which inhibits reduced glutathione (GSH) synthesis. Vanin-1 promotes inflammation and tissue injury partly by inducing oxidative stress, and partly by peroxisome proliferator-activated receptor gamma (PPARγ) expression. Vascular smooth muscle cells (SMCs) contribute to neointimal hyperplasia in response to injury, by multiple mechanisms including modulation of oxidative stress and PPARγ. Therefore, we tested the hypothesis that vanin-1 drives SMC activation and neointimal hyperplasia. We studied reactive oxygen species (ROS) generation and functional responses to platelet-derived growth factor (PDGF) and the pro-oxidant diamide in cultured mouse aortic SMCs, and also assessed neointima formation after carotid artery ligation in vanin-1 deficiency. Vnn1(-/-) SMCs demonstrated decreased oxidative stress, proliferation, migration, and matrix metalloproteinase 9 (MMP-9) activity in response to PDGF and/or diamide, with the effects on proliferation linked, in these studies, to both increased GSH levels and PPARγ expression. Vnn1(-/-) mice displayed markedly decreased neointima formation in response to carotid artery ligation, including decreased intima:media ratio and cross-sectional area of the neointima. We conclude that vanin-1, via dual modulation of GSH and PPARγ, critically regulates the activation of cultured SMCs and development of neointimal hyperplasia in response to carotid artery ligation. Vanin-1 is a novel potential therapeutic target for neointimal hyperplasia following revascularization.     

Mass tagging approach for mitochondrial thiol proteins

A mass tagging approach is described for mitochondrial thiol proteins under nondenaturing conditions. This approach utilizes stable isotope-coded, thiol-reactive (4-iodobutyl)triphenylphosphonium (IBTP) reagents, i.e., the isotopomers IBTP-d(0) and IBTP-d(15). The mass spectrometric properties of IBTP-labeled peptides were evaluated using an ESI-q-TOF and a MALDI-TOF/TOF instrument. High energy collision induced dissociation (CID) in the TOF/TOF instrument caused side-chain fragmentation in the butyltriphenylphosphonium moiety-containing Cys-residue. By contrast, low energy CID in the qTOF instrument yielded sequence tags of IBTP-labeled peptides that were suitable for automated database searching. The IBTP labeling strategy was then applied to the analysis of a protein extract obtained from cardiac mitochondria. The relative abundance measurements for identified IBTP-labeled peptides showed an average variability for peptide quantitation of approximately 10% based on peak area ratios of ion signals for the d(0)/d(15)-tagged peptide pairs. The reactivity of the IBTP reagents was further studied by molecular modeling and visualization. The present study suggests that the IBTP reagent seems to show a bias toward highly surface-exposed protein thiols. Hence, the described mass tagging approach might become potentially useful in redox proteomics studies designed to identify protein thiols that are particularly prone to oxidative modifications.     

Dispersal and species’ responses to climate change

Dispersal is fundamental in determining biodiversity responses to rapid climate change, but recently acquired ecological and evolutionary knowledge is seldom accounted for in either predictive methods or conservation planning. We emphasise the accumulating evidence for direct and indirect impacts of climate change on dispersal. Additionally, evolutionary theory predicts increases in dispersal at expanding range margins, and this has been observed in a number of species. This multitude of ecological and evolutionary processes is likely to lead to complex responses of dispersal to climate change. As a result, improvement of models of species’ range changes will require greater realism in the representation of dispersal. Placing dispersal at the heart of our thinking will facilitate development of conservation strategies that are resilient to climate change, including landscape management and assisted colonisation. Synthesis This article seeks synthesis across the fields of dispersal ecology and evolution, species distribution modelling and conservation biology. Increasing effort focuses on understanding how dispersal influences species' responses to climate change. Importantly, though perhaps not broadly widely‐recognised, species' dispersal characteristics are themselves likely to alter during rapid climate change. We compile evidence for direct and indirect influences that climate change may have on dispersal, some ecological and others evolutionary. We emphasise the need for predictive modelling to account for this dispersal realism and highlight the need for conservation to make better use of our existing knowledge related to dispersal.     

Construction of a quinoa (Chenopodium quinoa Willd.) BAC library and its use in identifying genes encoding seed storage proteins

Quinoa (Chenopodium quinoa Willd.) is adapted to the harsh environments of the Andean Altiplano region. Its seeds have a well-balanced amino acid composition and exceptionally high protein content with respect to human nutrition. Quinoa grain is a staple in the diet of some of the most impoverished people in the world. The plant is an allotetraploid displaying disomic inheritance (2n=4x=36) with a di-haploid genome of 967 Mbp (megabase pair), or 2C=2.01 pg. We constructed two quinoa BAC libraries using BamHI (26,880 clones) and EcoRI (48,000 clones) restriction endonucleases. Cloned inserts in the BamHI library average 113 kb (kilobase) with approximately 2% of the clones lacking inserts, whereas cloned inserts in the EcoRI library average 130 kb and approximately 1% lack inserts. Three plastid genes used as probes of high-density arrayed blots of 73,728 BACs identified approximately 2.8% of the clones as containing plastid DNA inserts. We estimate that the combined quinoa libraries represent at least 9.0 di-haploid nuclear genome equivalents. An average of 12.2 positive clones per probe were identified with 13 quinoa single-copy ESTs as probes of the high-density arrayed blots, suggesting that the estimate of 9.0× coverage of the genome is conservative. Utility of the BAC libraries for gene identification was demonstrated by probing the library with a partial sequence of the 11S globulin seed storage protein gene and identifying multiple positive clones. The presence of the 11S globulin gene in four of the clones was verified by direct comparison with quinoa genomic DNA on a Southern blot. Besides serving as a useful tool for gene identification, the quinoa BAC libraries will be an important resource for physical mapping of the quinoa genome.     

The Saccharomyces cerevisiae v-SNARE Vti1p Is Required for Multiple Membrane Transport Pathways to the Vacuole

The interaction between v-SNAREs on transport vesicles and t-SNAREs on target membranes is required for membrane traffic in eukaryotic cells. Here we identify Vti1p as the first v-SNARE protein found to be required for biosynthetic traffic into the yeast vacuole, the equivalent of the mammalian lysosome. Certain vti1-ts yeast mutants are defective in alkaline phosphatase transport from the Golgi to the vacuole and in targeting of aminopeptidase I from the cytosol to the vacuole. VTI1 interacts genetically with the vacuolar t-SNARE VAM3, which is required for transport of both alkaline phosphatase and aminopeptidase I to the vacuole. The v-SNARE Nyv1p forms a SNARE complex with Vam3p in homotypic vacuolar fusion; however, we find that Nyv1p is not required for any of the three biosynthetic pathways to the vacuole. v-SNAREs were thought to ensure specificity in membrane traffic. However, Vti1p also functions in two additional membrane traffic pathways: Vti1p interacts with the t-SNAREs Pep12p in traffic from the TGN to the prevacuolar compartment and with Sed5p in retrograde traffic to the cis-Golgi. The ability of Vti1p to mediate multiple fusion steps requires additional proteins to ensure specificity in membrane traffic.     

The evolution of myiasis in humans and other animals in the Old and New Worlds (part I): phylogenetic analyses

Myiasis, the infestation of live vertebrates with dipterous larvae, seems to take two distinct forms that, it has been suggested, evolved from two distinct phylogenetic roots: saprophagous and sanguinivorous. However, the convergent evolution of morphological and life-history traits seems to have had a major role in simplifying this overall assessment of the evolutionary routes by which myiasis arose. Moreover, this somewhat simplistic division is further complicated by the existence of both ectoparasitic and endoparasitic species of myiasis-causing Diptera, the evolutionary affinities of which remain to be resolved. To understand how different forms of parasitism arose, the evolution of the various groups of myiasis-causing flies must be separated from the evolution of the myiasis habit per se. Until recently, evolutionary studies of myiasis-causing flies were little more than discussions of morphology-based taxonomy. Since the mid-1990s, however, several formal phylogenies - based on both morphological and, increasingly, molecular data - have been published, enabling reassessment of the hypotheses concerning myiasis evolution. In part I of this review, we focus on some recent landmark studies in this often-neglected branch of parasitology and draw together phylogenetic studies based on molecular and morphological data to provide a framework for the subsequent analysis of biochemical, immunological, behavioural, biogeographical and fossil evidence relating to the evolution of myiasis.     

A role for vimentin in Crohn disease

Crohn disease (CD), one of the major chronic inflammatory bowel diseases, occurs anywhere in the gastrointestinal tract with discontinuous transmural inflammation. A number of studies have now demonstrated that genetic predisposition, environmental influences and a dysregulated immune response to the intestinal microflora are involved. Major CD susceptibility pathways uncovered through genome-wide association studies strongly implicate the innate immune response (NOD2), in addition to the more specific acquired T cell response (IL23R, ICOSLG) and autophagy (ATG16L1, IRGM). Examination of the disease-associated microbiome, although complex, has identified several potentially contributory microorganisms, most notably adherent-invasive E.coli strains (AIEC), which have been isolated by independent investigators in both adult and pediatric CD patients. Here we discuss our recent finding that the type-III intermediate filament (IF) protein VIM/vimentin is a novel NOD2 interacting protein that regulates NOD2 activities including inflammatory NFKB1 signaling, autophagy and bacterial handling.