J A Bowman

Publications (2)4.13 Total impact

• Article: Structure and sequence conservation of a putative hypoxia response element in the lactate dehydrogenase-B gene of Fundulus.

  B B Rees, J A Bowman, P M Schulte
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  ABSTRACT: Many aquatic habitats are characterized by periodic or sustained episodes of low oxygen concentration, or hypoxia, and organisms that survive in these habitats do so by utilizing a suite of behavioral, physiological and biochemical adjustments to low oxygen (1-3). In the killifish Fundulus heteroclitus, one response to prolonged exposure to hypoxia is an increase in the activity of lactate dehydrogenase-B (LDH-B), the terminal enzyme of anaerobic glycolysis, in liver tissue (4). An increase in glycolytic enzyme activity also occurs in mammalian cells during hypoxia, a process due, in part, to increased rates of gene transcription mediated by the hypoxia-inducible transcription factor, HIF-1 (5). Given that a homolog of HIF-1 has been identified in fish (6), we hypothesized that HIF might be involved in the observed up-regulation of LDH-B in F. heteroclitus. Herein, we describe the presence of DNA elements in intron 2 of the Ldh-B gene from F. heteroclitus that resemble hypoxia response elements (HRE) describedfor mammalian genes (7-10). Specifically, over a region of approximately 50 base pairs we identified two consensus HIF-1 binding sites, as well as DNA elements that may bind other transcription factors (e.g., cyclic AMP response elements; CRE). We found that these sites were perfectly conserved among geographically diverse populations of F. heteroclitus, as well as being highly conserved among multiple species in the genus Fundulus. The spacing, orientation, and sequence conservation of these putative regulatory elements suggest that they may be functionally involved in the hypoxic regulation of Ldh-B in these fish.
  Biological Bulletin 07/2001; 200(3):247-51. · 1.70 Impact Factor
• Article: On the dependence of the elasticity and strength of cancellous bone on apparent density.

  J C Rice, S C Cowin, J A Bowman
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  ABSTRACT: This paper presents a statistical analysis of the pooled data from a number of previous experiments concerning the dependence of the Young's moduli and strength of cancellous bone tissue upon apparent density. The results show that both the Young's moduli and the strength are proportional to the square of apparent density of the tissue and are therefore proportional to one another. It is shown that the coefficient of proportionality is different for human and bovine tissue. It is concluded that the suggestion of Wolff (Das Gesetz der Transformation der Knochen, Hirschwald, Berlin, 1892) that compact bone tissue is simply more dense cancellous bone tissue is not an accurate statement when only the mechanical properties of these two tissues are considered. It is noted that estimates for the elastic modulus of the individual trabecula of human cancellous bone vary from 1 to 20 GPa and it is suggested that this question needs further study.
  Journal of Biomechanics 02/1988; 21(2):155-68. · 2.43 Impact Factor