Panthera leo are a carnivorous species with significant bone growth occurring from gestation to 3–4 yrs. In captivity, species are not necessarily subject to all stresses influencing bone development that would otherwise result in the wild. The factors fully influencing bone development in the wild are unknown. The purpose of this study was to determine if differences in morphometric measurements are present between wild and captive populations of lions, specifically in the regions of mastication. Twenty-one different measurements were taken on fifty-seven skulls. Morphometric measurements of museum specimens from the wild were compared with specimens obtained from zoos and other captive environments. Results from analysis indicate significant differences between captive and wild specimens. The majority of these variances were in the regions of mastication; areas influenced by external stress. Wild specimens possess greater morphometric dimensions in regions of stress.

The mechanism of senescence, permanent G1 arrest, is gradually becoming elucidated; however, the exact function of senescence remains unclear. A marker assay detecting the acidic senescence-associated beta-galactosidase (saβgal) has been used as an indicator for cellular senescence. However, more recently, others have shown that expression of this low pH saβgal may not be solely limited to senescent cells. This study has extended the findings on stress induction of saβgal by assessing the enzyme activity in additional species (monkey and rat) and determining if saβgal is stimulated by the stresses of temperature and alkalinity. Our results support previous data that saβgal is not solely a marker of senescence but may in fact be a highly conserved, ubiquitous marker of cellular stress. Additionally, we feel that our data, in conjunction with the literature, indicate that this sa (stress associated) βgal may play a pivotal role in multiple signal pathways in the cell.

The enhanced green fluorescent protein (EGFP) is a macromolecule which fluoresces green under specific wavelengths of light. It has been widely used as a tool to study cell structure and function. EGFP-PTS1 is a fusion of the EGFP gene and a peroxisome targeting sequence (PTS1). Attachment of the PTS1 localizes EGFP to the peroxisome, an organelle found in eukaryotic cells. In this work, DNA encoding an EGFP-PTS1 fusion was inserted into a plasmid which contained a selectable marker gene for adenine biosynthesis (ADE1). The plasmid, called pCO1, was transformed into an adenine auxotrophic strain (ade1) of the yeast Pichia pastoris. The ade1 strain, which is pink in color, could not synthesize its own adenine and thus could not survive without this nitrogenous base in its growth medium. The ADE1 gene on pCO1 acted as a form of selection to identify cells transformed by the plasmid. Colonies transformed by pCO1 were white in color and could grow in medium without the supplemental addition of adenine. Cells harboring pCO1 expressed EGFP-PTS1 protein when grown on methanol because the gene fusion was put under the control of the methanol-inducible AOX1 promoter. By utilizing fluorescence microscopy, we show that these pCO1-transformed yeast express EGFP-PTS1 and localize it to their peroxisomes. The experimental method detailed here has been modified to teach concepts of yeast genetics and protein expression to large numbers of laboratory students in an undergraduate setting.

Southwestern College was one of the founding chapters of Beta Beta Beta in 1925 and was awarded the Outstanding Chapter designation in 2002. The campus, home of the Moundbuilders, is filled with boulders and rocks that have been carved and inscribed to honor the achievements of the school and its students. This is the text of a speech delivered by Dr. Patrick Ross, chapter advisor for Southwestern's Delta chapter, at the unveiling of the Beta Beta Beta rock on May of 2004.