A declaration of intent in the kittiwake gull (Rissa tridactyla)

During the breeding seasons 1979–1982 observations were made of the vocal behaviour of the kittiwake gull (Rissa tridactyla). Attention was directed at the vocal behaviour emitted immediately preceding a bird's departure from the nest and partner. The data indicate that the kittiwake consistently makes only one type of vocalization (the Pre-departure Call) prior to departure and that the behaviour communicates intention to leave nest and partner. An analysis of the behavioural interactions reveals that the Pre-departure Call given by one bird elicits five different categories of response in the other. The data reveal that consequent partner behaviour either sanctioned or prevented absence. The functional significance of the results is discussed.     

A chemically mediated amperometric biosensor for monitoring eubacterial respiration

The development of a novel biosensor system for measuring the respiratory activity of whole eubacterial cells is described. The biosensor incorporates a physically immobilized layer of cells held in intimate contact with an amperometric transducing electrode and uses a chemical mediator, potassium ferricyanide, to divert electrons from the respiratory system of the bacteria to the poised electrode. The current thus produced is proportional to the level of respiratory activity of the immobilized bacterial cells and can be monitored by a computer interface system. The paper outlines the principles of the biosensor and describes the results of a screen of potentially useful eubacteria. Also described are the effects of physical parameters on the sensor and a strategy for the long term preservation of the biosensor by freeze-drying.     

Use of creatine in the elderly and evidence for effects on cognitive function in young and old

The ingestion of the dietary supplement creatine (about 20 g/day for 5 days or about 2 g/day for 30 days) results in increased skeletal muscle creatine and phosphocreatine. Subsequently, the performance of high-intensity exercise tasks, which rely heavily on the creatine-phosphocreatine energy system, is enhanced. The well documented benefits of creatine supplementation in young adults, including increased lean body mass, increased strength, and enhanced fatigue resistance are particularly important to older adults. With aging and reduced physical activity, there are decreases in muscle creatine, muscle mass, bone density, and strength. However, there is evidence that creatine ingestion may reverse these changes, and subsequently improve activities of daily living. Several groups have demonstrated that in older adults, short-term high-dose creatine supplementation, independent of exercise training, increases body mass, enhances fatigue resistance, increases muscle strength, and improves the performance of activities of daily living. Similarly, in older adults, concurrent creatine supplementation and resistance training increase lean body mass, enhance fatigue resistance, increase muscle strength, and improve performance of activities of daily living to a greater extent than resistance training alone. Additionally, creatine supplementation plus resistance training results in a greater increase in bone mineral density than resistance training alone. Higher brain creatine is associated with improved neuropsychological performance, and recently, creatine supplementation has been shown to increase brain creatine and phosphocreatine. Subsequent studies have demonstrated that cognitive processing, that is either experimentally (following sleep deprivation) or naturally (due to aging) impaired, can be improved with creatine supplementation. Creatine is an inexpensive and safe dietary supplement that has both peripheral and central effects. The benefits afforded to older adults through creatine ingestion are substantial, can improve quality of life, and ultimately may reduce the disease burden associated with sarcopenia and cognitive dysfunction.     

The orientation of homing pigeons in relation to change in sun declination

Summary The sun navigation hypothesis ofMatthews is briefly reviewed with special reference to his sun occlusion experiment which supports this hypothesis. The results of a similar experiment are presented in which 13 young pigeons were kept from sight of the sun during a seven day period including the fall equinox while the sun height at noon decreased 3° 6.7. When the birds were released from a point 93 km. south of their loft they were exposed to a noon sun height equal to that of a point north of their home loft eight days earlier. Nevertheless they showed a northward orientation as did the 10 control birds with no difference in homing performance between the experimental and control groups. These results are not in agreement with those ofMatthews and do not support his sun navigation hypothesis.

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Zusammenfassung Die Sonnennavigations-Hypothese vonMatthews wird kurz besprochen, besonders im Hinblick auf den Warte-Versuch (Sun occlusion experiment), der unter anderem zur Prüfung der Hypothese angestellt wurde. Die Ergebnisse eines im Wilhelmshavener Gebiet angestellten Warteversuchs werden mitgeteilt: 13 Tauben wurden um die Herbst-Tagundnachtgleiche für 7 Tage ohne Sicht der Sonne gehalten, deren Mittagshöhe in dieser Zeit um 3° 6,7 abnahm. Als die Vögel 93 km südlich ihres Heimatorts aufgelassen wurden, befanden sie sich im Gebiet einer Mittags-Sonnenhöhe gleich der, welche vor der Warteperiode etwa 2° nördlich vom Heimatort herrschte. Trotzdem flogen sie gleich den Kontrollen nordwärts ab. Auch im Heimkehrerfolg bestand kein Unterschied zwischen Versuchs-und Kontrolltauben. Diese Ergebnisse stimmen mit den vonMatthews berichteten nicht überein und stützen seine Sonnen-Navigations-Hypothese nicht.

     

Analysis of cytoskeletal and motility proteins in the sea urchin genome assembly

The sea urchin embryo is a classical model system for studying the role of the cytoskeleton in such events as fertilization, mitosis, cleavage, cell migration and gastrulation. We have conducted an analysis of gene models derived from the Strongylocentrotus purpuratus genome assembly and have gathered strong evidence for the existence of multiple gene families encoding cytoskeletal proteins and their regulators in sea urchin. While many cytoskeletal genes have been cloned from sea urchin with sequences already existing in public databases, genome analysis reveals a significantly higher degree of diversity within certain gene families. Furthermore, genes are described corresponding to homologs of cytoskeletal proteins not previously documented in sea urchins. To illustrate the varying degree of sequence diversity that exists within cytoskeletal gene families, we conducted an analysis of genes encoding actins, specific actin-binding proteins, myosins, tubulins, kinesins, dyneins, specific microtubule-associated proteins, and intermediate filaments. We conducted ontological analysis of select genes to better understand the relatedness of urchin cytoskeletal genes to those of other deuterostomes. We analyzed developmental expression (EST) data to confirm the existence of select gene models and to understand their differential expression during various stages of early development.     

COPI activity coupled with fatty acid biosynthesis is required for viral replication

During infection by diverse viral families, RNA replication occurs on the surface of virally induced cytoplasmic membranes of cellular origin. How this process is regulated, and which cellular factors are required, has been unclear. Moreover, the host-pathogen interactions that facilitate the formation of this new compartment might represent critical determinants of viral pathogenesis, and their elucidation may lead to novel insights into the coordination of vesicular trafficking events during infection. Here we show that in Drosophila cells, Drosophila C virus remodels the Golgi apparatus and forms a novel vesicular compartment, on the surface of which viral RNA replication takes place. Using genome-wide RNA interference screening, we found that this step in the viral lifecycle requires at least two host encoded pathways: the coat protein complex I (COPI) coatamer and fatty acid biosynthesis. Our results integrate, clarify, and extend numerous observations concerning the cell biology of viral replication, allowing us to conclude that the coupling of new cellular membrane formation with the budding of these vesicles from the Golgi apparatus allows for the regulated generation of this new virogenic organelle, which is essential for viral replication. Additionally, because these pathways are also limiting in flies and in human cells infected with the related RNA virus poliovirus, they may represent novel targets for antiviral therapies.