Myoglobin as a test case in the construction of space-filling models of proteins using dihedral angles

A method for construction of space-filling models of proteins of improved accuracy was developed from the dihedral angle technique proposed by Hauschka and Segal (P. V. Hauschka and D. M. Segal, Biopolymers, 4 , 1051, 1966). Tools were designed to facilitate the marking of accurate reference lines on component atoms and a simple method for cementing the fixed angles was devised. The torsion angle method was extended to include all side chains. The improved technique was used to assemble a model of sperm whale metmyoglobin from the x-ray data.     

The Saccharomyces cerevisiae ARO1 gene. An example of the co-ordinate regulation of five enzymes on a single biosynthetic pathway

The ARO1 gene of Saccharomyces cerevisiae encodes the arom multifunctional enzyme. Specific inhibitors of amino acid biosynthesis have been used to obtain evidence that expression of a cloned ARO1 gene is regulated in response to amino acid limitation. Northern blot analysis and sequence studies indicate that ARO1 is regulated by the well characterised S. cerevisiae 'general control' mechanism. This provides a very economical means of simultaneously tailoring the synthesis of five shikimate pathway enzymes to the needs of the cell.     

Environmental,behavioral, and habitat variables influencing body temperature in radio-tagged bullsnakes, Pituophis catenifer sayi

Studies regarding the thermal ecology of snakes are important to understanding their life histories. Yet, little is known about the thermal ecology of the North American genus Pituophis, which includes the bullsnake (Pituophis catenifer sayi). In an attempt to determine which independent variables significantly affected the thermal ecology of free-ranging bullsnakes, we tracked 12–19 radio-tagged individuals weekly from 2003 to 2005 in Wisconsin (USA) with temperature-sensitive transmitters. Although snake body temperature was found to vary based on several variables treated independently, two separate three-way interactions among variables were significant. We believe our results support the notion that P. c. sayi thermoconforms to environmental conditions in the upper Midwest, but more research on the topic is necessary.     

Protective effects of agomelatine on testicular damage caused by bortezomib

Bortezomib is a chemotherapeutic agent used to treat several cancers; however, it exhibits severe side effects in testicular tissue. We investigated the use of agomelatine to prevent testicular tissue damage caused by bortezomib. We used 36 male Sprague-Dawley rats divided randomly into six equal groups: group 1, no treatment control; group 2, agomelatine treatment only; group 3, bortezomib treatment only for 48 h; group 4, bortezomib + agomelatine treatment for 48 h; group 5, bortezomib treatment only for 72 h; and group 6, bortezomib + agomelatine treatment for 72 h. After treatments, the rats were sacrificed and testicular tissue was harvested. Lipid oxidation (LPO) and superoxide dismutase (SOD) levels in the tissues were determined using biochemical methods. Tissue samples also were examined using histopathological and immunohistochemical techniques. The LPO level was increased, while the SOD level was decreased in the bortezomib treated groups. We found that agomelatine treatment normalized LPO and SOD activities in the bortezomib treated groups. In the spermatogonia and Sertoli cells, the staining density of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and caspase 3 were decreased in the bortezomib + agomelatine groups at both 48 and 72 h compared to bortezomib only treated groups. We observed maturation arrest, basal membrane thickening, increase in inflammatory cells and connective tissue, and edema between germ cells in the bortezomib only treated groups. By contrast, normal basal membrane, less edema and more normal maturation were observed in the bortezomib + agomelatine groups at 48 and 72 h. We found that agomelatine reduced the damaging effects of bortezomib. The use of agomelatine to prevent bortezomib induced testicular tissue damage in human patients should be investigated further.