Optimization of a series of quinazolinone-derived antagonists of CXCR3

The evaluation of the CXCR3 antagonist AMG 487 in clinic trials was complicated due to the formation of an active metabolite. In this Letter, we will discuss the further optimization of the quinazolinone series that led to the discovery of compounds devoid of the formation of the active metabolite that was seen with AMG 487. In addition, these compounds also feature increased potency and good pharmacokinetic properties. We will also discuss the efficacy of the lead compound 34 in a mouse model of cellular recruitment induced by bleomycin.     

A region of calpastatin domain L that reprimes cardiac L-type Ca2+ channels

Calpastatin, an endogenous inhibitor of calpain, is composed of domain L and four repetitive homologous domains 1-4. Domains 1-4 inhibit calpain, whereas domain L partially reprimes L-type Ca2+ channels for voltage-gated activation. In the present study, the effects on Ca2+ channel activity of four isoforms and a series of fragments of calpastatin domain L were investigated in guinea-pig ventricular myocytes with the patch-clamp method. With one exception, all the isoforms and fragment peptides that contained amino acid residues 54-64 of domain L reprimed the Ca2+ channels to comparable levels (9-15% of control activity) to those observed previously with a full-length form of calpastatin. These results suggest that the region containing amino acid residues 54-64 (EGKPKEHTEPK) is responsible for the Ca2+ channel repriming function of calpastatin domain L.     

The Effects of Chilling on the Fecundity and Life Span of Mass-reared Parasitoids (Hymenoptera: Braconidae) of the Mediterranean Fruit Fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae)

Suppression of Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), populations may be achieved through the mass-rearing and augmentative aerial release of opiine braconid parasitoids. Typically, aerial release techniques require up to one hour of chilling of adult parasitoids at temperatures as low as 3.5°C prior to their dissemination. Such chilling potentially could affect the subsequent performance of the insects. Among three species of the genus Diachasmimorpha longicaudata (Ashmead), tryoni (Cameron), and krausii (Fullaway) there was little or no affect of chilling in the laboratory on female longevity, production of daughters, or offspring sex ratio. This is consistent with previous experiments that found chilling to have no discernable effect on the short-term mortality of D. tryoni or on its ability to take flight immediately after aerial release. While there was little effect of chilling on longevity and fecundity in a species from another opiine genus, Fopius arisanus (Sonan), exposure to low temperatures did result in a significantly more male-biased offspring sex ratio.     

Desulfovibrio vulgaris bacterioferritin uses H(2)O(2) as a co-substrate for iron oxidation and reveals DPS-like DNA protection and binding activities

β?-GPI (β?-glycoprotein I) is a plasma glycoprotein ascribed with an anti-angiogenic function; however, the biological role and molecular basis of its action in cell migration remain unknown. The aim of the present study was to assess the contribution of β?-GPI to HAEC (human aortic endothelial cell) migration and the details of its underlying mechanism. Using wound healing and Boyden chamber assays, we found that β?-GPI inhibited endothelial cell migration, which was restored by its neutralizing antibody. NF-κB (nuclear factor κB) inhibitors and lentiviral siRNA (small interfering RNA) silencing of NF-κB significantly attenuated the inhibitory effect of β?-GPI on cell migration. Moreover, β?-GPI was found to induce IκBα (inhibitor of NF-κB) phosphorylation and translocation of p65 and p50. We further demonstrated that mRNA and protein levels of eNOS [endothelial NO (nitric oxide) synthase] and NO production were all increased by β?-GPI and these effects were remarkably inhibited by NF-κB inhibitors and siRNAs of p65 and p50. Furthermore, β?-GPI-mediated inhibition of cell migration was reversed by eNOS inhibitors and eNOS siRNAs. The findings of the present study provide novel insight into the ability of β?-GPI to inhibit endothelial cell migration predominantly through the NF-κB/eNOS/NO signalling pathway, which indicates a potential direction for clinical therapy in vascular diseases.     

Towards genomic and proteomic studies of protein phosphorylation in plant-pathogen interactions

Phosphorylation is an effective method of post-translational protein modification but understanding its significance is hindered by its biological complexity. Many protein kinases and phosphatases have been identified that connect signal perception mechanisms to plant defence responses. Recent studies of mitogen-activated protein kinases, calcium-dependent protein kinases and other kinases and phosphatases have revealed some important mechanisms, but have also raised new questions. The regulation of any phosphorylation pathway is complex and dynamic. There are many protein kinases and phosphatases in the plant genome, which makes it hard to delineate the phosphorylation machinery fully. Genomics and proteomics have already identified new components and will continue to influence the study of phosphorylation profoundly in plant-pathogen interactions.     

Uniconazole-induced thermotolerance in soybean seedling root tissue

Soybean [Glycine max(L.) Merr. cv. A2] seeds were germinated in 0 or 1 mg 1¹ (3.4 uM) uniconazole, after which seedling roots were excised and exposed to 22 or 48°C for 90 min. Prior to the temperature treatments there were few ultrastructural differences between uniconazole-treated seedling roots and the controls. Following exposure to 48°C, electron micrographs revealed near complete loss of normal ultrastructure in control epidermal root cells, whereas cellular integrity was maintained in treated roots, indicating that uniconazole conferred tolerance to high temperature. Total electrolyte, sugar and K⁺ leakage were all greater from control roots than treated roots during exposure to 48°C. Proline content in the roots was unaffected by uniconazole at 22°C but was 25–30% greater in treated tissue than in controls following exposure to 48°C. Malondialdehyde content was unaffected by uniconazole at 22°C but was nearly 20% less in treated tissue than in controls following high temperature exposure. This indicates that uniconazole decreased high-temperature-induced lipid peroxidation. Uniconazole elevated several antiox-idant systems in the roots, including water-soluble sulfhydryl concentration and catalase, peroxidase and superoxide dismutase activities. These findings are consistent with the hypothesis that uniconazole-induced stress tolerance is due, at least in part, to enhanced antioxidant activity which reduces stress-related oxidative damage to cell membranes.     

A synthesis of methane emissions from 71 northern,temperate, and subtropical wetlands

Wetlands are the largest natural source of atmospheric methane. Here, we assess controls on methane flux using a database of approximately 19 000 instantaneous measurements from 71 wetland sites located across subtropical, temperate, and northern high latitude regions. Our analyses confirm general controls on wetland methane emissions from soil temperature, water table, and vegetation, but also show that these relationships are modified depending on wetland type (bog, fen, or swamp), region (subarctic to temperate), and disturbance. Fen methane flux was more sensitive to vegetation and less sensitive to temperature than bog or swamp fluxes. The optimal water table for methane flux was consistently below the peat surface in bogs, close to the peat surface in poor fens, and above the peat surface in rich fens. However, the largest flux in bogs occurred when dry 30‐day averaged antecedent conditions were followed by wet conditions, while in fens and swamps, the largest flux occurred when both 30‐day averaged antecedent and current conditions were wet. Drained wetlands exhibited distinct characteristics, e.g. the absence of large flux following wet and warm conditions, suggesting that the same functional relationships between methane flux and environmental conditions cannot be used across pristine and disturbed wetlands. Together, our results suggest that water table and temperature are dominant controls on methane flux in pristine bogs and swamps, while other processes, such as vascular transport in pristine fens, have the potential to partially override the effect of these controls in other wetland types. Because wetland types vary in methane emissions and have distinct controls, these ecosystems need to be considered separately to yield reliable estimates of global wetland methane release.     

Structure of antimicrobial peptides and lipid membranes probed by interface-sensitive X-ray scattering

The conformation and correlations of amphiphilic and antimicrobial peptides and the associated changes of lipid bilayers can be studied in oriented lipid membranes deposited on solid substrates. Here we review recent work on these systems, as studied by modern interface-sensitive X-ray and neutron scattering methods. Density profile, short range order of acyl chains and molecular conformations of peptides and lipids are probed in the fluid state of the bilayer. With an emphasis on technical aspects, we review recent work illustrating the potential of the methods and discuss its potential in the field.