Effects of melezitose and stachyose on adult longevity and virus persistence in Culicoides sonorensis (Diptera: Ceratopogonidae)

A wide variety of blood-feeding Diptera feed on extrafloral sugar sources such as homopteran honeydew. The significance of these sugar sources to insect survival and disease transmission is poorly known. Culicoides sonorensis, a biting midge, can survive on plant sugars but might also feed on homopteran honeydew. The survival of C. sonorensis fed 10% melezitose or 10% stachyose was compared to that of C. sonorensis fed 10% sucrose. A significantly greater number of C. sonorensis survived longer when fed melezitose than when fed either stachyose or sucrose. The effect of sugar meals on vector competence was measured using bluetongue and epizootic hemorrhagic disease viruses. There was no significant difference in viral persistence. However, if C. sonorensis feeds on homopteran honeydew in the wild, a larger number of midges could survive to transmit orbiviruses.     

Isolation of an active step I spliceosome and composition of its RNP core

Formation of catalytically active RNA structures within the spliceosome requires the assistance of proteins. However, little is known about the number and nature of proteins needed to establish and maintain the spliceosome's active site. Here we affinity-purified human spliceosomal C complexes and show that they catalyse exon ligation in the absence of added factors. Comparisons of the composition of the precatalytic versus the catalytic spliceosome revealed a marked exchange of proteins during the transition from the B to the C complex, with apparent stabilization of Prp19-CDC5 complex proteins and destabilization of SF3a/b proteins. Disruption of purified C complexes led to the isolation of a salt-stable ribonucleoprotein (RNP) core that contained both splicing intermediates and U2, U5 and U6 small nuclear RNA plus predominantly U5 and human Prp19-CDC5 proteins and Prp19-related factors. Our data provide insights into the spliceosome's catalytic RNP domain and indicate a central role for the aforementioned proteins in sustaining its catalytically active structure.     

Hot Jupiters from secular planet-planet interactions

About 25 per cent of 'hot Jupiters' (extrasolar Jovian-mass planets with close-in orbits) are actually orbiting counter to the spin direction of the star. Perturbations from a distant binary star companion can produce high inclinations, but cannot explain orbits that are retrograde with respect to the total angular momentum of the system. Such orbits in a stellar context can be produced through secular (that is, long term) perturbations in hierarchical triple-star systems. Here we report a similar analysis of planetary bodies, including both octupole-order effects and tidal friction, and find that we can produce hot Jupiters in orbits that are retrograde with respect to the total angular momentum. With distant stellar mass perturbers, such an outcome is not possible. With planetary perturbers, the inner orbit's angular momentum component parallel to the total angular momentum need not be constant. In fact, as we show here, it can even change sign, leading to a retrograde orbit. A brief excursion to very high eccentricity during the chaotic evolution of the inner orbit allows planet-star tidal interactions to rapidly circularize that orbit, decoupling the planets and forming a retrograde hot Jupiter.     

Reduction of bovine pulmonary hypertension by normoxia,verapamil and hexaprenaline

Summary In calves with hypoxic pulmonary hypertension, resistance was reduced by 40±3% with normoxia, 19±4% with verapamil, and 60±1% with hexoprenaline. It is possible that the increased resistance during normoxia is due partly to vasoconstriction rather than solely to vascular thickening, and that the vasoconstriction is due to an abnormality in calcium metabolism by the hypertensive vasculature.Acknowledgments. We thank Rosann Glas, Mary Munroe, Diann Smith and Linda Panepinto for technical assistance. This work was supported by the Colorado Heart Association and by the National Institutes of Health Grants HL-05973 and HL-29237. Verapamil (Isoptin) was supplied by Knoll Pharmaceutical Co. Hexoprenaline (ST 1512 HCl, Ipradol) was supplied by Österreichische Stickstoffwerke Linz.     

Ollier disease and Maffucci syndrome are caused by somatic mosaic mutations of IDH1 and IDH2

Ollier disease and Maffucci syndrome are characterized by multiple central cartilaginous tumors that are accompanied by soft tissue hemangiomas in Maffucci syndrome. We show that in 37 of 40 individuals with these syndromes, at least one tumor has a mutation in isocitrate dehydrogenase 1 (IDH1) or in IDH2, 65% of which result in a R132C substitution in the protein. In 18 of 19 individuals with more than one tumor analyzed, all tumors from a given individual shared the same IDH1 mutation affecting Arg132. In 2 of 12 subjects, a low level of mutated DNA was identified in non-neoplastic tissue. The levels of the metabolite 2HG were measured in a series of central cartilaginous and vascular tumors, including samples from syndromic and nonsyndromic subjects, and these levels correlated strongly with the presence of IDH1 mutations. The findings are compatible with a model in which IDH1 or IDH2 mutations represent early post-zygotic occurrences in individuals with these syndromes.     

Hemodynamic and ventilatory effects of skin-cooling in cattle.

Cooling the skin of cattle at an ambient temperature of 25 degrees C decreased cardiac output and increased systemic and pulmonary vascular resistances. Minute ventilation was reduced by about 50%. There was no change in alveolar ventilation as measured by arterial blood gases. These results indicate that thermoregulatory ventilation has significant cardiopulmonary effects in cattle at normal laboratory temperatures.