Brain catecholamines and organ weight of mice genetically selected for high and low blood pressure.

Statistically significant differences were found between the high and low genetically selected blood pressure lines for systolic blood pressure, norepinephrine content of whole brain, absolute heart weight, heart to b. wt ratio, kidney weight, kidney to b. wt ratio, and adrenal to b. wt ratio.     

Dietary overlap in giant salamanders (Dicamptodon): applying null models to resource partitioning

We examined stomach contents of preserved specimens of larval Pacific giant salamander ( Dicamptodon tenebrosus ) and Cope's giant salamander ( D. copei ) collected from sympatric and allopatric stream populations. The dietary components of these specimens were used to calculate dietary overlap between the 2 species and to determine if changes in overlap existed between sympatric and allopatric populations. To statistically test overlap values, a randomization algorithm was used to construct a simulated data matrix (i.e., null model) in order to compare observed values of dietary overlap to a distribution of overlap values from the null model. Significant levels ( P < 0.05) of dietary overlap occurred in all cases of sympatry as well as allopatry. Average dietary overlap in sympatry was significantly lower than in allopatry, suggesting a dietary shift when in sympatry to reduce competition. Diet composition also differed between sympatric and allopatric populations of each species, further suggesting a partitioning of food resources by one or both species when in the presence of its congener.     

Microelectrode studies of spontaneous potentials from chick embryo telencephalon in vitro

Résumé A l'aide de micro-électrodes, des potentiels rythmiques spontanés ont été enregistrés dans du tissu télencéphalique d'embryons de poulets âgès de 14 jours, in vitro. Ces potentiels sont semblables à ceux précédemment décrits en utilisant des électrodes de 80 en platine. La possibilité pour ces potentiels d'être produits par les neurones de l'explant est discuté.     

Generation and annotation of the DNA sequences of human chromosomes 2 and 4

Human chromosome 2 is unique to the human lineage in being the product of a head-to-head fusion of two intermediate-sized ancestral chromosomes. Chromosome 4 has received attention primarily related to the search for the Huntington's disease gene, but also for genes associated with Wolf-Hirschhorn syndrome, polycystic kidney disease and a form of muscular dystrophy. Here we present approximately 237 million base pairs of sequence for chromosome 2, and 186 million base pairs for chromosome 4, representing more than 99.6% of their euchromatic sequences. Our initial analyses have identified 1,346 protein-coding genes and 1,239 pseudogenes on chromosome 2, and 796 protein-coding genes and 778 pseudogenes on chromosome 4. Extensive analyses confirm the underlying construction of the sequence, and expand our understanding of the structure and evolution of mammalian chromosomes, including gene deserts, segmental duplications and highly variant regions.     

Aurignacian structural features and burials at Cueva Morín (Santander, Spain)

The discovery of what seems to be the foundation of a hut, an alignment of six post holes, and two graves, one of which contains human remains in a remarkable state of preservation, provides important new information about the earliest Aurignacian occupation of northern Spain.     

加拿大不列颠哥伦比亚东北部伊维湖地区几维特阶斯雷夫波音特组的层孔虫

本文描述采自泥盆系几维特阶斯雷夫波音特组石灰岩的层孔虫9属11种,标本为石油天然气钻孔的礁相岩心。石灰岩多为砾状灰岩及粒泥状灰岩,被沥青质充填,微细构造保存完好。层孔虫以穹状及枝状为主。本动物群中的Trupetostroma warreni,Stachyodes thomasclarki,S.spongiosa以及Actinostroma cf.clathratum均与天鹅山生物确相同,而以出现Actinostroma whiteavesii及Pseudotrupetostroma vitreum为明显特征。后一种以及Taleastroma logansportense种一块保存完好的标本,说明此动物群与波兰及美国俄亥俄山谷地区的几维特期动物群的关系密切。     

Structural and functional conservation of key domains in InsP3 and ryanodine receptors

Inositol-1,4,5-trisphosphate receptors (InsP(3)Rs) and ryanodine receptors (RyRs) are tetrameric intracellular Ca(2+) channels. In each of these receptor families, the pore, which is formed by carboxy-terminal transmembrane domains, is regulated by signals that are detected by large cytosolic structures. InsP(3)R gating is initiated by InsP(3) binding to the InsP(3)-binding core (IBC, residues 224-604 of InsP(3)R1) and it requires the suppressor domain (SD, residues 1-223 of InsP(3)R1). Here we present structures of the amino-terminal region (NT, residues 1-604) of rat InsP(3)R1 with (3.6??) and without (3.0??) InsP(3) bound. The arrangement of the three NT domains, SD, IBC-β and IBC-α, identifies two discrete interfaces (α and β) between the IBC and SD. Similar interfaces occur between equivalent domains (A, B and C) in RyR1 (ref. 9). The orientations of the three domains when docked into a tetrameric structure of InsP(3)R and of the ABC domains docked into RyR are remarkably similar. The importance of the α-interface for activation of InsP(3)R and RyR is confirmed by mutagenesis and, for RyR, by disease-causing mutations. Binding of InsP(3) causes partial closure of the clam-like IBC, disrupting the β-interface and pulling the SD towards the IBC. This reorients an exposed SD loop ('hotspot' (HS) loop) that is essential for InsP(3)R activation. The loop is conserved in RyR and includes mutations that are associated with malignant hyperthermia and central core disease. The HS loop interacts with an adjacent NT, suggesting that activation re-arranges inter-subunit interactions. The A domain of RyR functionally replaced the SD in full-length InsP(3)R, and an InsP(3)R in which its C-terminal transmembrane region was replaced by that from RyR1 was gated by InsP(3) and blocked by ryanodine. Activation mechanisms are conserved between InsP(3)R and RyR. Allosteric modulation of two similar domain interfaces within an N-terminal subunit reorients the first domain (SD or A domain), allowing it, through interactions of the second domain of an adjacent subunit (IBC-β or B domain), to gate the pore.     

Global variation in copy number in the human genome

Copy number variation (CNV) of DNA sequences is functionally significant but has yet to be fully ascertained. We have constructed a first-generation CNV map of the human genome through the study of 270 individuals from four populations with ancestry in Europe, Africa or Asia (the HapMap collection). DNA from these individuals was screened for CNV using two complementary technologies: single-nucleotide polymorphism (SNP) genotyping arrays, and clone-based comparative genomic hybridization. A total of 1,447 copy number variable regions (CNVRs), which can encompass overlapping or adjacent gains or losses, covering 360 megabases (12% of the genome) were identified in these populations. These CNVRs contained hundreds of genes, disease loci, functional elements and segmental duplications. Notably, the CNVRs encompassed more nucleotide content per genome than SNPs, underscoring the importance of CNV in genetic diversity and evolution. The data obtained delineate linkage disequilibrium patterns for many CNVs, and reveal marked variation in copy number among populations. We also demonstrate the utility of this resource for genetic disease studies.