Angiotensin II inhibits growth of cultured embryonic renomedullary interstitial cells through the AT2 receptor

Angiotensin II inhibits growth of cultured embryonic renomedullary interstitial cells through the AT2 receptor. The high abundance of angiotensin II (Ang II) AT2, relative to the AT1 receptor subtype in developing kidneys may be related to their potential as mediators of cell growth, although little evidence exists to support this concept. Renomedullary interstitial cells (RMICs) differentiate early in embryonic kidneys and are important in subsequent nephron development. These cells have been shown in vivo to possess AT2 binding sites, although the functional significance of these sites remains unknown. The aim of the current investigation was to examine the actions of Ang II on cultured embryonic renomedullary interstitial cells (ERMICs). 125I-[Sar1, Ile8]Ang II specifically bound to AT1 and AT2 receptors on ERMICs, and their mRNAs were detected by reverse transcription—polymerase chain reaction (RT-PCR). Angiotensin II (10−6M) increased intracellular IP3 concentrations at 20 seconds, and decreased intracellular cAMP concentrations after 10 minutes. Angiotensin II (10−6M) induced an increase in [3H]thymidine incorporation, mediated through the AT1 receptor subtype. Basic fibroblast growth factor (bFGF; 20 ng/ml) also increased 3[H]thymidine incorporation after 24 hours of treatment, an effect that was attenuated by subsequent addition of Ang II (10−6M). This antiproliferative action of Ang II was blocked by PD 123319 (10−6M), an AT2 receptor antagonist, and was not affected by losartan (10−6M), an AT1 receptor antagonist. These results indicate a dual role for Ang II in regulating ERMIC mitogenesis: a growth stimulating effect mediated by the AT1 receptor subtype, and an antiproliferative effect mediated by the AT2 receptor subtype

Sea anemones (Exaiptasia pallida) use a secreted adhesive and complex pedal disc morphology for surface attachment

Background The mechanism by which sea anemones attach to surfaces underwater remains elusive, which is surprising given their ubiquitous distribution in the world’s oceans and tractability for experimental biology. Their adhesion is mechanically interesting, bridging the interface between very hard and soft materials. The Cnidaria are thought to have evolved adhesion to surfaces at least 505 Ma ago implying that, among the Metazoa, only Porifera developed this capability earlier. The purpose of this study was primarily to address an existing hypothesis, that spirocysts (a sticky class of cnidocyst) facilitate adhesion to surfaces, as observed during prey capture. Results We demonstrated conclusively that spirocysts were not involved in the pedal disc adhesion of Exaiptasia pallida. Second, we applied a variety of imaging methods to develop an understanding of the true adhesion mechanism. Morphological studies using scanning electron microscopy identified a meshwork of adhesive material, unique to the pedal disc. Serial block-face SEM highlighted four classes of cells that could secrete the adhesive from the pedal disc ectoderm. A variety of histochemical techniques identified proteins, glycans and quinones in the cell contents and secreted adhesive, with variation in contents of specific cell-types in different areas of the body. Conclusions Spirocysts are not used by Exaiptasia pallida for adhesion to surfaces. Instead, a structurally and compositionally complex secreted glue was observed, firmly attaching the animals underwater. The results of this study provide a basis for further investigations of adhesion in Cnidaria, and establish E. pallida as a new model organism for bioadhesion research

Interdisciplinary approaches to a connected landscape: upland survey in the Northern Ochils

The key to understanding a landscape is through its connections, which tie together people and environment within and beyond that landscape and across many different periods. This is particularly true of the northern face of the Ochil Hills in central Scotland, which is characterised by dense networks of connections between lowlands and uplands, local and regional. To trace those connections we integrate the results of walkover survey, aerial archaeology, excavations, documentary analysis and place name analysis, revealing significant continuities and differences in the networks and relationships that have connected this landscape across time and space. Iron Age hillforts used their prominence and monumentality to guide people along very specific routes across the Ochils. Regular seasonal movements of cattle and herders in the medieval and post-medieval periods were closely related to the agriculture and settlement they encountered on the way: this interaction can be clearly seen in the elaborate intertwining of paths, braided cattle tracks, farmsteads and enclosures, most strikingly in the 18th century. Such intricate connections across the landscape are equally keyed in to the specifics of particular locations and to much broader networks and historical change

The relevance of chemistry practicals - first year students’ perspective at a regional university in Victoria, Australia

The use of laboratory practical sessions in chemistry to enhance student learning is common practice however, student perspectives of the relevance of this experience to their learning is difficult to find. A unique situation arose with a cohort of first-year undergraduate students where they completed one introductory chemistry course with no laboratory component, followed by a second introductory chemistry course with a laboratory component included. Upon completion of both chemistry courses the students were surveyed to gauge their perceptions, attitudes and experiences relating to chemistry laboratory sessions and whether they aided their understanding of chemical concepts covered in lectures and tutorials. Students (88%) considered the laboratory work to be essential and/or important in aiding their learning of chemistry, highlighting that their learning was enhanced due to the cross-over between theory and practice, while also gaining a variety of laboratory skills. A more diverse range of laboratory activities was suggested, but some students noted that they appreciated some skills repetition. Incorporating a combination of introductory and inquiry based sessions could meet the needs of both of these groups of students, while enhancing skills in other areas

Surface modification of spray dried food and emulsion powders with surface-active proteins : A review

Spray drying is a well-established and widely used method for transforming a wide range of liquid food products into powder form. Stickiness is the limitation in spray drying of different sugar and acid-rich food products. To minimize this problem process and material science based approaches are in place. However, these remedies have their own drawbacks. Surface modification of droplets/particles is a novel way to minimize stickiness. It is timely that the research efforts on surface modification of droplets/particles be reviewed. Therefore, this review highlights the recent research dealing with surface modification of emulsions and spray dried powders. The theoretical foundation, mechanisms and methods used to achieve surface modification of food and emulsion powders are highlighted. © 2009 Elsevier Ltd. All rights reserved

Using digital image analysis to accurately determine the thousand kernel weight of randomly distributed barley, malt and wheat samples

Rapid, accurate and non-subjective grain tests help growers and processors agree on a fair price and ensure that the grain is used for the most appropriate purpose. Common tests include protein, moisture, test (hectolitre) weight, screenings and dockages for pests, disease and foreign matter (Vicgrain, 2000). Each test contributes to a more comprehensive assessment of the grain. The tests assist breeders when selecting promising new cultivars. Plant breeders and maltsters also use the thousand kernel weight (TKW) test, which provides additional information on seed morphology. The test indicates the average kernel weight, with the units expressed as grams per thousand seeds. TKWs are valuable to maltsters and millers as high TKW kernels are plumper, malt and/or mill more evenly and have a higher proportion of endosperm than small kernels. The high TKW grains also produce more attractive malt (Stuart, 1998). TKWs assist breeders in selecting large kernel cultivars and permit growers to calculate their optimum sowing rates (Schwarz and Horsley, 1995).E

Elucidating an amorphous form stabilization mechanism of tenapanor hydrochloride: crystal structure analysis using Xray diffraction, NMR crystallography and molecular modelling

By the combined use of powder and single crystal X-ray diffraction, solid-state NMR, and molecular modelling, the crystal structures of two systems containing the unusually large tenapanor drug molecule have been determined: the free form, ANHY and a dihydrochloride salt form, 2HCl. Dynamic nuclear polarization (DNP) assisted solid-state NMR (SSNMR) crystallography investigations were found essential for the final assignment, and were used to validate the crystal structure of ANHY. From the structural informatics analysis of ANHY and 2HCl, conformational ring differences in one part of the molecule were observed which influences the relative orientation of a methyl group on a ring nitrogen and thereby impacts the crystallizability of the dihydrochloride salt. From quantum chemistry calculations, the dynamics between different ring conformations in tenapanor is predicted to be fast. Addition of HCl to tenapanor results in general in a mixture of protonated ring conformers and hence a statistical mix of diastereoisomers which builds up the amorphous form, a-2HCl. This was qualitatively verified by 13C CP/MAS NMR investigations of the amorphous form. Thus, to form any significant amount of the crystalline material 2HCl, which originates from the minor (i.e., energetically less stable) ring conformations, one needs to involve nitrogen deprotonation to allow exchange between minor and major conformations of ANHY in solution. Thus, by controlling the solution pH value to well below the pKa of ANHY, the equilibrium between ANHY and 2HCl can be controlled and by this mechanism the crystallization of 2HCl can be avoided and the amorphous form of the dichloride salt can therefore be stabilized

Amelogenesis imperfecta

Amelogenesis imperfecta (AI) represents a group of developmental conditions, genomic in origin, which affect the structure and clinical appearance of enamel of all or nearly all the teeth in a more or less equal manner, and which may be associated with morphologic or biochemical changes elsewhere in the body. The prevalence varies from 1:700 to 1:14,000, according to the populations studied. The enamel may be hypoplastic, hypomineralised or both and teeth affected may be discoloured, sensitive or prone to disintegration. AI exists in isolation or associated with other abnormalities in syndromes. It may show autosomal dominant, autosomal recessive, sex-linked and sporadic inheritance patterns. In families with an X-linked form it has been shown that the disorder may result from mutations in the amelogenin gene, AMELX. The enamelin gene, ENAM, is implicated in the pathogenesis of the dominant forms of AI. Autosomal recessive AI has been reported in families with known consanguinity. Diagnosis is based on the family history, pedigree plotting and meticulous clinical observation. Genetic diagnosis is presently only a research tool. The condition presents problems of socialisation, function and discomfort but may be managed by early vigorous intervention, both preventively and restoratively, with treatment continued throughout childhood and into adult life. In infancy, the primary dentition may be protected by the use of preformed metal crowns on posterior teeth. The longer-term care involves either crowns or, more frequently these days, adhesive, plastic restorations

Omics‐based molecular analyses of adhesion by aquatic invertebrates

Many aquatic invertebrates are associated with surfaces, using adhesives to attach to the substratum for locomotion, prey capture, reproduction, building or defence. Their intriguing and sophisticated biological glues have been the focus of study for decades. In all but a couple of specific taxa, however, the precise mechanisms by which the bioadhesives stick to surfaces underwater and (in many cases) harden have proved to be elusive. Since the bulk components are known to be based on proteins in most organisms, the opportunities provided by advancing ‘omics technologies have revolutionised bioadhesion research. Time‐consuming isolation and analysis of single molecules has been either replaced or augmented by the generation of massive data sets that describe the organism's translated genes and proteins. While these new approaches have provided resources and opportunities that have enabled physiological insights and taxonomic comparisons that were not previously possible, they do not provide the complete picture and continued multi‐disciplinarity is essential. This review covers the various ways in which ‘omics have contributed to our understanding of adhesion by aquatic invertebrates, with new data to illustrate key points. The associated challenges are highlighted and priorities are suggested for future research