Stem cell engraftment at the endosteal niche is specified by the calcium-sensing receptor

During mammalian ontogeny, haematopoietic stem cells (HSCs) translocate from the fetal liver to the bone marrow, where haematopoiesis occurs throughout adulthood. Unique features of bone that contribute to a microenvironmental niche for stem cells might include the known high concentration of calcium ions at the HSC-enriched endosteal surface. Cells respond to extracellular ionic calcium concentrations through the seven-transmembrane-spanning calcium-sensing receptor (CaR), which we identified as being expressed on HSCs. Here we show that, through the CaR, the simple ionic mineral content of the niche may dictate the preferential localization of adult mammalian haematopoiesis in bone. Antenatal mice deficient in CaR had primitive haematopoietic cells in the circulation and spleen, whereas few were found in bone marrow. CaR-/- HSCs from fetal liver were normal in number, in proliferative and differentiative function, and in migration and homing to the bone marrow. Yet they were highly defective in localizing anatomically to the endosteal niche, behaviour that correlated with defective adhesion to the extracellular matrix protein, collagen I. CaR has a function in retaining HSCs in close physical proximity to the endosteal surface and the regulatory niche components associated with it.     

GLC determination of betahistine in serum

A gas chromatographic method was developed for the determination of betahistine in serum in the range of 0.6-6.0 microgram/ml.     

Human-specific loss of regulatory DNA and the evolution of human-specific traits

Humans differ from other animals in many aspects of anatomy, physiology, and behaviour; however, the genotypic basis of most human-specific traits remains unknown. Recent whole-genome comparisons have made it possible to identify genes with elevated rates of amino acid change or divergent expression in humans, and non-coding sequences with accelerated base pair changes. Regulatory alterations may be particularly likely to produce phenotypic effects while preserving viability, and are known to underlie interesting evolutionary differences in other species. Here we identify molecular events particularly likely to produce significant regulatory changes in humans: complete deletion of sequences otherwise highly conserved between chimpanzees and other mammals. We confirm 510 such deletions in humans, which fall almost exclusively in non-coding regions and are enriched near genes involved in steroid hormone signalling and neural function. One deletion removes a sensory vibrissae and penile spine enhancer from the human androgen receptor (AR) gene, a molecular change correlated with anatomical loss of androgen-dependent sensory vibrissae and penile spines in the human lineage. Another deletion removes a forebrain subventricular zone enhancer near the tumour suppressor gene growth arrest and DNA-damage-inducible, gamma (GADD45G), a loss correlated with expansion of specific brain regions in humans. Deletions of tissue-specific enhancers may thus accompany both loss and gain traits in the human lineage, and provide specific examples of the kinds of regulatory alterations and inactivation events long proposed to have an important role in human evolutionary divergence.     

Evaluating the geographic distribution of plants in Utah from the Atlas of Vascular Plants of Utah

Locations of 73,219 vascular plant vouchers representing 2438 species were digitized from the Atlas of the Vascular Plants of Utah (Albee et al. 1988). Source maps consist of 1:6,000,000-scale shaded relief maps of Utah with points representing collection locations by species. Location points, representing 1 or more specimens, were transposed onto these maps from the approximately 400,000 herbarium records of 3 major universities and federal land management agencies. These source maps were digitized into an ARC/Info TM database in order to reproduce the atlas in digital form. Analysis of all locations revealed a mapping bias of the original authors to avoid placing sample locations on county boundaries and over major river corridors. A comparison between ecoregions and elevation showed that the Colorado Plateau and Wasatch/Uinta Mountains have the highest species diversity, and that areas of low elevation (1000-2000 m) have the highest number of unique species in the state. Further, species richness is related to elevation and to ecoregion boundaries.     

Osteology and myology of the head and neck regions of Callisaurus, Cophosaurus, Holbrookia, and Uma (Reptilia: Iguanidae)

A detailed study of the anterior osteology and myology of Callisaurus, Cophosaurus, Holbrookia, and Uma reveals the phylogenetic relationships among the sand lizards. An SPSS discriminant analysis of osteological characters combined with myological characters indicates that Callisaurus is most primitive, Cophosaurus and Holbrookia are most closely related, and Uma is the most distinct of the sand lizard genera. Because of close relationships between Cophosaurus and Holbrookia, it is postulated that earlessness evolved once, and Cophosaurus is returned to synonymy under Holbrookia.     

Redescription of the Tyee Sucker, Catostomus tsiltcoosensis (Catostomidae)

We resurrect Catostomus tsiltcoosensis, the Tyee sucker of Oregon coastal rivers, from the synonymy of Catostomus macrocheilus and compare it with its congeners. Catostomus tsiltcoosensis is superficially similar to disjunctly distributed Catostomus occidentalis of the Sacramento drainage and Catostomus ardens of the Upper Snake River and Bonneville Basin. However, the gill raker structure, wide frontoparietal fontanelle, location of the ninth cranial foramen, scale radii patterns, and cytochrome b sequences clearly align C. tsiltcoosensis with C. macrocheilus rather than C. occidentalis. Differences in counts of infraorbital pores and dorsal fin rays, in body depth proportions, and in cytochrome b sequences distinguish C. tsiltcoosensis and C. macrocheilus. Within C. tsiltcoosensis, specimens from each of the 4 main drainages (north to south—Siuslaw, Umpqua, Coos, and Coquille) were reciprocally monophyletic based on cytochrome b data but showed no differences in the morphological features examined. Both C. tsiltcoosensis and another Oregon coastal taxon Catostomus rimiculus were paraphyletic based on cytochrome b. Although such discordant mitochondria results can be due to introgression, incomplete lineage sorting, and paralogy, other evidence suggests that introgression and lateral transfer of mitochondria explains the cytochrome b pattern in C. rimiculus. We speculate that lateral transfer might also be responsible for the pattern in C. tsiltcoosensis, except that the Coquille River population appears not to have been included in recent transfers.