Vertebrate fauna of a radioactive leaching pond complex in southeastem Idaho

An inventory of the terrestrial vertebrate fauna and the seasonal occurrence of each species was determined for a man - made radioactive leaching pond complex in southeastern Idaho. Three reptile, 11 mammal, and 94 bird species were identified from February 1974 through January 1978. Fewest species were observed during the winter and most during the summer. Eight bird species nested at the pond complex, while 19 species of birds were common or seasonally abundant. It appears that the Test Reactor Area radioactive leaching pond complex is an important water source and provides habitat for some species of wildlife.     

Phosphorylation of WAVE1 regulates actin polymerization and dendritic spine morphology

WAVE1--the Wiskott-Aldrich syndrome protein (WASP)--family verprolin homologous protein 1--is a key regulator of actin-dependent morphological processes in mammals, through its ability to activate the actin-related protein (Arp2/3) complex. Here we show that WAVE1 is phosphorylated at multiple sites by cyclin-dependent kinase 5 (Cdk5) both in vitro and in intact mouse neurons. Phosphorylation of WAVE1 by Cdk5 inhibits its ability to regulate Arp2/3 complex-dependent actin polymerization. Loss of WAVE1 function in vivo or in cultured neurons results in a decrease in mature dendritic spines. Expression of a dephosphorylation-mimic mutant of WAVE1 reverses this loss of WAVE1 function in spine morphology, but expression of a phosphorylation-mimic mutant does not. Cyclic AMP (cAMP) signalling reduces phosphorylation of the Cdk5 sites in WAVE1, and increases spine density in a WAVE1-dependent manner. Our data suggest that phosphorylation/dephosphorylation of WAVE1 in neurons has an important role in the formation of the filamentous actin cytoskeleton, and thus in the regulation of dendritic spine morphology.     

Ryk-deficient mice exhibit craniofacial defects associated with perturbed Eph receptor crosstalk

Secondary palate formation is a complex process that is frequently disturbed in mammals, resulting in the birth defect cleft palate. Gene targeting has identified components of cytokine/growth factor signalling systems such as Tgf-alpha/Egfr, Eph receptors B2 and B3 (Ephb2 and Ephb3, respectively), Tgf-beta2, Tgf-beta3 and activin-betaA (ref. 3) as regulators of secondary palate development. Here we demonstrate that the mouse orphan receptor 'related to tyrosine kinases' (Ryk) is essential for normal development and morphogenesis of craniofacial structures including the secondary palate. Ryk belongs to a subclass of catalytically inactive, but otherwise distantly related, receptor protein tyrosine kinases (RTKs). Mice homozygous for a null allele of Ryk have a distinctive craniofacial appearance, shortened limbs and postnatal mortality due to feeding and respiratory complications associated with a complete cleft of the secondary palate. Consistent with cleft palate phenocopy in Ephb2/Ephb3-deficient mice and the role of a Drosophila melanogaster Ryk orthologue, Derailed, in the transduction of repulsive axon pathfinding cues, our biochemical data implicate Ryk in signalling mediated by Eph receptors and the cell-junction-associated Af-6 (also known as Afadin). Our findings highlight the importance of signal crosstalk between members of different RTK subfamilies.     

Distribution and ecological characteristics of Lewisia longipetala (Piper) Clay, a high-altitude endemic plant

Lewisia longipetala (Piper) Clay is a high-altitude endemic found in the northern Sierra Nevada. The characteristics of 12 sites with L. longipetala , which represent all known populations, were studied to define habitat requirements of the species. Meso- and microscale characteristics of the habitat were examined, including characteristics of the associated plant community. Average plant size and plant density of L. longipetala were also determined for each population. Similar measurements were made on 6 populations of Lewisia pygmaea (A. Gray) Robinson, a more common Lewisia . Populations of L. longipetala that had larger plants and higher plant density were associated with gently sloped, north-facing sites that were near large, persistent snowbanks and had low vegetative cover. Plant species associated with populations of L. longipetala were similar among the 12 sites and were indicative of mesic, rocky alpine sites. These types of plant communities found near persistent snowbanks are often termed snow-bed vegetation. In contrast, L. pygmaea was found to be less site specific. Lewisia pygmaea was found adjacent to or interspersed with L. longipetala at 5 sites, but was found in areas associated with a higher percentage of herbaceous cover and a wider variety of species. This integration of ecological community information for L. longipetala populations contributes to the interim management and long-term monitoring of this species by providing needed information concerning its habitat and environmental specificity.     

Functional diversity of melanopsins and their global expression in the teleost retina

Melanopsin (OPN4) is an opsin photopigment that, in mammals, confers photosensitivity to retinal ganglion cells and regulates circadian entrainment and pupil constriction. In non-mammalian species, two forms of opn4 exist, and are classified into mammalian-like (m) and non-mammalian-like (x) clades. However, far less is understood of the function of this photopigment family. Here we identify in zebrafish five melanopsins (opn4m-1, opn4m-2, opn4m-3, opn4x-1 and opn4x-2), each encoding a full-length opsin G protein. All five genes are expressed in the adult retina in a largely non-overlapping pattern, as revealed by RNA in situ hybridisation and immunocytochemistry, with at least one melanopsin form present in all neuronal cell types, including cone photoreceptors. This raises the possibility that the teleost retina is globally light sensitive. Electrophysiological and spectrophotometric studies demonstrate that all five zebrafish melanopsins encode a functional photopigment with peak spectral sensitivities that range from 470 to 484 nm, with opn4m-1 and opn4m-3 displaying invertebrate-like bistability, where the retinal chromophore interchanges between cis- and trans-isomers in a light-dependent manner and remains within the opsin binding pocket. In contrast, opn4m-2, opn4x-1 and opn4x-2 are monostable and function more like classical vertebrate-like photopigments, where the chromophore is converted from 11-cis to all-trans retinal upon absorption of a photon, hydrolysed and exits from the binding pocket of the opsin. It is thought that all melanopsins exhibit an invertebrate-like bistability biochemistry. Our novel findings, however, reveal the presence of both invertebrate-like and vertebrate-like forms of melanopsin in the teleost retina, and indicate that photopigment bistability is not a universal property of the melanopsin family. The functional diversity of these teleost melanopsins, together with their widespread expression pattern within the retina, suggests that melanopsins confer global photosensitivity to the teleost retina and might allow for direct “fine-tuning” of retinal circuitry and physiology in the dynamic light environments found in aquatic habitats.     

Vertebrate fauna of the Idaho National Environmental Research Park

The relative abundance, habitat use, and seasonal occurrence are reported for the 6 fish, 1 amphibian, 9 reptile, 164 bird, and 39 mammal species recorded on the Idaho National Environmental Research Park in southeastern Idaho.     

Observations of captive Rocky Mountain mule deer behavior

Observations were made on the behavior of a captive herd of Rocky Mountain mule deer ( Odocoileus hemionus hemionus ). Comparisons in general behavior patterns were made between captive and wild deer. Similar behavior was exhibited by captive and wild deer. Captive deer (as well as other species) may be useful for study of certain behavioral aspects of their wild counterparts.     

The identification of chemical intermediates in enzyme catalysis by the rapid quench-flow technique

Traditionally, enzyme transient kinetics have been studied by the stopped-flow and rapid quench-flow (QF) methods. Whereas stopped-flow is the more convenient, it suffers from two weaknesses: optically silent systems cannot be studied, and when there is a signal it cannot always be assigned to a particular step in the reaction pathway. QF is a chemical sampling method; reaction mixtures are aged for a few milliseconds or longer, ‘stopped’ by a quenching agent and the product or the intermediate is measured by a specific analytical method. Here we show that by exploiting the array of current analytical methods and different quenching agents, the QF method is a key technique for identifying, and for characterising kinetically, intermediates in enzyme reaction pathways and for determining the order by which bonds are formed or cleaved by enzymes acting on polymer substrates such as DNA. Received 24 May 2006; received after revision: 3 July 2006; accepted 19 July 2006