The distribution and activity of tachykinin-related peptides in the blood-feeding bug, Rhodnius prolixus

The invertebrate tachykinin-related peptides (TRPs) with the conserved C-terminal sequence FX1GX2Ramide shows sequence similarity to the vertebrate tachykinins after which they are named, and are hypothesized to be ancestrally related. In this study a polyclonal antiserum generated against a locust tachykinin (LomTK I), was used to demonstrate the presence and describe the distribution of LomTK-like immnoreactivity in the CNS and gut of Rhodnius prolixus. Reverse phase high performance liquid chromatography (RP-HPLC) was used in combination with a sensitive radioimmunoassay (RIA) to demonstrate picomolar amounts of immunoreactive material in the CNS, and femptomolar amounts associated with the hindgut. Furthermore, the results from CNS extracts separated by RP-HPLC, suggest that at least two tachykinin isoforms exist in R. prolixus. A hindgut contraction assay was developed to quantify the myotropic effects of selected LomTKs on R. prolixus hindgut contraction. Both LomTK I and II caused an increase in the frequency of hindgut contractions with EC50 values of 3.6x10(-8)M and 3.8x10(-8)M for LomTK I and II, respectively.     

Sustainable Rangeland Grazing in Norse Faroe

The introduction of domestic livestock, particularly sheep, and rangeland grazing by Norse settlers to Faroe during the ninth century has generally been described as a major pressure on a sensitive landscape, leading to rapid and widespread vegetation change and contributing to land degradation. This view has, however, been developed without consideration of Norse grazing management practices which may have served to minimize grazing impacts on landscapes as well as sustaining and enhancing vegetation and livestock productivity. These alternative scenarios are considered using a historical grazing management simulation model with Faroese climate and vegetation inputs and given archaeological, historical and palaeoenvironmental parameters. Three contrasting rangeland areas are investigated and, based on the maximum number of ewe/lamb pairs the rangeland could sustain, modeling suggests that utilizable biomass declined with the onset of grazing activity, but not to a level that would cause major changes in vegetation cover or contribute to soil erosion even under climatically determined poor growth conditions. When rangeland areas partitioned into what are termed hagi and partir are modeled, grazing levels are still within rangeland carrying capacities, but productivities are variable. Some rangeland areas increase biomass and livestock productivities and biomass utilization rates while other rangeland areas that were too finely partitioned were likely to suffer substantial decline in livestock productivity. Partitioning of rangeland is a likely contributor to long-term differentiation of landscapes and the relative success of settlements across Faroe beyond the Norse period.     

Nephric duct insertion is a crucial step in urinary tract maturation that is regulated by a Gata3-Raldh2-Ret molecular network in mice

Urinary tract development depends on a complex series of events in which the ureter moves from its initial branch point on the nephric duct (ND) to its final insertion site in the cloaca (the primitive bladder and urethra). Defects in this maturation process can result in malpositioned ureters and hydronephrosis, a common cause of renal disease in children. Here, we report that insertion of the ND into the cloaca is an unrecognized but crucial step that is required for proper positioning of the ureter and that depends on Ret signaling. Analysis of Ret mutant mice at birth reveals hydronephrosis and defective ureter maturation, abnormalities that our results suggest are caused, at least in part, by delayed insertion of the ND. We find a similar set of malformations in mutants lacking either Gata3 or Raldh2. We show that these factors act in parallel to regulate ND insertion via Ret. Morphological analysis of ND extension in wild-type embryos reveals elaborate cellular protrusions at ND tips that are not detected in Ret, Gata3 or Raldh2 mutant embryos, suggesting that these protrusions may normally be important for fusion with the cloaca. Together, our studies reveal a novel Ret-dependent event, ND insertion, that, when abnormal, can cause obstruction and hydronephrosis at birth; whether ND defects underlie similar types of urinary tract abnormalities in humans is an interesting possibility.     

Mild hydrogenolysis of in-situ and isolated Pinus radiata lignins

The Pd/C-catalysed hydrogenolysis of in-situ and isolated lignins from Pinus radiata wood was investigated to gain a more complete understanding of the factors affecting yield and composition of the hydrogenolysis products. Such hydrogenolysis products could potentially be refined into aromatic feedstock chemicals providing sustainable alternatives to petroleum-derived phenols. Lignins were converted into solvent-soluble oils composed of monomeric, dimeric and oligomeric products in high yields, up to 89% of the original lignin. The main monomer products were dihydroconiferyl alcohol and 4-n-propyl guaiacol. Dimeric and oligomeric compounds constituted 75% of the hydrogenolysis oils and were mainly composed of dihydroconiferyl alcohol and 4-n-propyl guaiacol units linked by β-5, 5-5, 4-O-5 and β-1 linkages. Hydrogenolysis of steam exploded wood gave lower yields of lignin hydrogenolysis products compared to unmodified wood due to fewer reactive aryl-ether linkages in the lignin.