STUDIES ON THE ANOMALOUS VISCOSITY AND FLOW-BIREFRINGENCE OF PROTEIN SOLUTIONS : III. CHANGES IN THESE PROPERTIES OF MYOSIN SOLUTIONS IN RELATION TO ADENOSINETRIPHOSPHATE AND MUSCULAR CONTRACTION

1. An investigation of the physicochemical properties of myosin has been carried out. Prepared under standard conditions, the ratio of flow-birefringence to protein concentration is uniform. The effect of electrolytes, pH, and urea on the flow-birefringence and viscosity (relative and anomalous) of myosin has been examined. 2. Decrease or abolition of flow-birefringence does not necessarily imply far reaching denaturation, since such effects can be reversed by a variety of means. 3. When a myosin solution is treated with adenosinetriphosphate, its flow-birefringence is decreased (average 48 per cent), its anomalous viscosity is retained, and its relative viscosity is decreased (average 14 per cent). The full effect of adenosinetriphosphate is obtained at 0.004 M; a molarity very much less than that of other substances which decrease the flow-birefringence of myosin. 4. The changes in the physicochemical properties of myosin brought about by adenosinetriphosphate are spontaneously reversible, and are connected with the enzymatic action of the protein as adenosinetriphosphatase. 5. Effects similar to those of adenosinetriphosphate on the physicochemical properties of purified myosin have been obtained so far only with inosinetriphosphate. 6. Inorganic phosphate is split off by myosin from inosinetriphosphate as well as from adenosinetriphosphate. Inorganic triphosphate is split by 1 to 2 per cent solution of three times precipitated myosin. 7. Adenosinediphosphate and inorganic triphosphate act as competitive inhibitors with adenosinetriphosphate, blocking the fall of flow-birefringence. 8. The implications of the results, and the conception of active enzymic groups attached to proteins participating in cell structure, whether contractile or non-contractile, are discussed in relation to present views on muscle physiology and other biological problems.     

Growth hormone signaling is necessary for lifespan extension by dietary methionine

Growth hormone significantly impacts lifespan in mammals. Mouse longevity is extended when growth hormone (GH) signaling is interrupted but markedly shortened with high‐plasma hormone levels. Methionine metabolism is enhanced in growth hormone deficiency, for example, in the Ames dwarf, but suppressed in GH transgenic mice. Methionine intake affects also lifespan, and thus, GH mutant mice and respective wild‐type littermates were fed 0.16%, 0.43%, or 1.3% methionine to evaluate the interaction between hormone status and methionine. All wild‐type and GH transgenic mice lived longer when fed 0.16% methionine but not when fed higher levels. In contrast, animals without growth hormone signaling due to hormone deficiency or resistance did not respond to altered levels of methionine in terms of lifespan, body weight, or food consumption. Taken together, our results suggest that the presence of growth hormone is necessary to sense dietary methionine changes, thus strongly linking growth and lifespan to amino acid availability.     

Ramet Demography of a Clonal Invader, <Emphasis Type="Italic">Arundo donax</Emphasis> (Poaceae), in Southern California

Arundo donax L. is a rhizomatous perennial, asexually reproducing species that has invaded riparian habitats throughout Mediterranean climate zones. This research evaluated ramet demography of A. donax in two California riparian communities that differed in nitrogen availability. Quadrats were established along 100 m transects at each site and oriented across the advancing fronts of established populations. Morphology and phenology were assessed monthly over 1 year for calculation of demographic parameters and rhizomes were excavated and mapped at the end of the experiment. A. donax exhibited seasonal patterns of recruitment but no dormancy at the high nitrogen site, while at the low nitrogen site no recruitment occurred in the winter and maximum recruitment was delayed by a month relative to the high nitrogen site. Spread of A. donax was delayed until spring and lower overall in the low nitrogen site compared to the high nitrogen site, where lower initial density, greater production of shoots, and higher linear and areal addition indicated that this population was spreading more rapidly. Temperature and precipitation influenced seasonality and amount of recruitment of A. donax in this study. Several recently established, immature clumps were found in gaps at the low nitrogen site, likely due to flood-mediated dispersal of propagules. Recruitment in these clumps occurred from shoot buds, in contrast to the mature populations that reproduced from rhizome buds. Ecologically based management strategies for A. donax and other exotic species should account for differences such as those described here and be tailored to local conditions where the species occurs.     

Rapid in vitro production of true-to-type plants of Pogostemon heyneaus through dedieferentiated axillary buds

Summary Rapid propagation of Pogostemon heyneanus Benth. (Lamiaceae) was accomplished through culture of node explants on Murashige and Skoog (MS) medium containing N ⁶-benzyladenine (BA). Random amplified polymorphic DNA (RAPD) and gas chromatographic (GC) analysis of in vitro-derived progenies were used to determine the true-to-type nature of in vitro-derived plantlets. At the optimum level of BA (2.22μM), the axillary buds underwent a degree of dedifferentiation to become small globular green masses from which a mean of 17.1 shoots were developed within 40d. Retaining the culture without subenlture enhanced the number of shoots (>30 shoots). Inereased callus proliferation was observed at higher concentrations of BA in concomitance with a reduction in number of shoots. However, prolonged culture without subculture (more than 60d) initiated 25–30 shoot buds from the callus. Culture of node segments excised from in vitro shoots on fresh medium with optimal BA (2.22μM) exhibited a similar response, but with an increase of shoots (mean of 26.3 shoots per node) within 40d. Subeulture of shoot clumps on half-strength MS basal medium resulted in elongation (more than 4cm) of most of the shoots along with the development of new shoots. Shoots developed were rooted most successfully on half-strength MS medium with 4.9 μM indole-3-butyric acid (IBA). Plantlets derived from the best rooting medium established in small cups exhibited 95% survival. Plantlets successfully established in field conditions exhibited morphological characteristies identical to the source plant. The RAPD profile of the in vitro-derived plants and source plant, using 10 random primers, was similar. The gas chromatogram of the extracted oils from in vitro-derived plants and the source plant showed similar patterns.     

ParseCNV integrative copy number variation association software with quality tracking

A number of copy number variation (CNV) calling algorithms exist; however, comprehensive software tools for CNV association studies are lacking. We describe ParseCNV, unique software that takes CNV calls and creates probe-based statistics for CNV occurrence in both case–control design and in family based studies addressing both de novo and inheritance events, which are then summarized based on CNV regions (CNVRs). CNVRs are defined in a dynamic manner to allow for a complex CNV overlap while maintaining precise association region. Using this approach, we avoid failure to converge and non-monotonic curve fitting weaknesses of programs, such as CNVtools and CNVassoc, and although Plink is easy to use, it only provides combined CNV state probe-based statistics, not state-specific CNVRs. Existing CNV association methods do not provide any quality tracking information to filter confident associations, a key issue which is fully addressed by ParseCNV. In addition, uncertainty in CNV calls underlying CNV associations is evaluated to verify significant results, including CNV overlap profiles, genomic context, number of probes supporting the CNV and single-probe intensities. When optimal quality control parameters are followed using ParseCNV, 90% of CNVs validate by polymerase chain reaction, an often problematic stage because of inadequate significant association review. ParseCNV is freely available at http://parsecnv.sourceforge.net.     

Detection of Proton Movement Directly across Viral Membranes To Identify Novel Influenza Virus M2 Inhibitors

The influenza virus M2 protein is a well-validated yet underexploited proton-selective ion channel essential for influenza virus infectivity. Because M2 is a toxic viral ion channel, existing M2 inhibitors have been discovered through live virus inhibition or medicinal chemistry rather than M2-targeted high-throughput screening (HTS), and direct measurement of its activity has been limited to live cells or reconstituted lipid bilayers. Here, we describe a cell-free ion channel assay in which M2 ion channels are incorporated into virus-like particles (VLPs) and proton conductance is measured directly across the viral lipid bilayer, detecting changes in membrane potential, ion permeability, and ion channel function. Using this approach in high-throughput screening of over 100,000 compounds, we identified 19 M2-specific inhibitors, including two novel chemical scaffolds that inhibit both M2 function and influenza virus infectivity. Counterscreening for nonspecific disruption of viral bilayer ion permeability also identified a broad-spectrum antiviral compound that acts by disrupting the integrity of the viral membrane. In addition to its application to M2 and potentially other ion channels, this technology enables direct measurement of the electrochemical and biophysical characteristics of viral membranes.     

Comparative phylogeography of Australo‐Papuan mangrove‐restricted and mangrove‐associated avifaunas

The world's richest mangrove‐restricted avifauna is in Australia and New Guinea. The history of differentiation of the species involved and their patterns of intraspecific genetic variation remain poorly known. Here, we use sequence data derived from two mitochondrial protein‐coding genes to study the evolutionary history of eight co‐distributed mangrove‐restricted and mangrove‐associated birds from the Australian part of this region. Utilizing a comparative phylogeographical framework, we observed that the study species present concordantly located phylogeographical breaks across their shared geographical distribution, a plausible signature of common mechanisms of vicariance underlying this pattern. Barriers such as the Canning Gap, Bonaparte Gap, and the Carpentarian Gaps all had important but varying degrees of impact on the studied species. The Burdekin Gap along Australia's eastern seaboard probably had only a minor influence as a barrier to gene flow in mangrove birds. Statistical phylogeographical simulations were able to discriminate among alternative scenarios involving six different geographical and temporal population separations. Species exhibiting recent colonizations into mangroves include Rhipidura phasiana, Myiagra ruficollis, and Myzomela erythrocephala. By contrast, Peneoenanthe pulverulenta, Pachycephala melanura, Pachycephala lanioides, Zosterops luteus, and Colluricincla megarhyncha all had deeper histories, reflected as more marked phylogeographical divisions separating populations on the eastern seaboard/Cape York Peninsula from more western regions such as the Arnhem Land, the Pilbara, and the Kimberley. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 574–598.     

The Immanence of Transcendence: God and the Devil on the Aberdeenshire Coast

In Gamrie (a Scottish fishing village of 700 people and 6 Protestant churches), local experiences of ‘divine providence’ and ‘demonic attack’ abound. Bodily fluids, scraps of paper, video cassettes and prawn trawlers were immanent carriers of divine and demonic activity. Viewed through the lens of Weberian social theory, the experiences of Scottish fisher families show how the life of the Christian resembles an enchanted struggle between God and the Devil with the Christian placed awkwardly in-between. Because, locally, ‘there is no such thing as coincidence’, these Christians expected to experience both the transcendent ordering of life by divine providence through God's immanence and the transcendent disordering of life by demonic attack through the Devil's immanence. Where this ordering and disordering frequently occurred through everyday objects, seemingly mundane events – being given a washing machine or feeling sleepy in church – were experienced as material indexes of spiritual reality. Drawing on the work of Cannell (on transcendence), Keane (on indexicality) and Wagner (on symbolic obviation), this paper argues that attending to the materiality of Scottish Protestantism better equips the anthropology of religion to understand Christian experience by positing immanence as a kind of transcendence and transcendence as a kind of immanence.