Search

Project-based (research-driven) laboratory courses stimulate student involvement, improve critical thinking and initiate cooperative learning. To this end, a 7-week laboratory project was designed for a sophomore cell biology course to reinforce the fundamental relationship between genotype and phenotype using yeast alcohol dehydrogenase I (ADH1). Working in pairs, students used site-directed mutagenesis to create a H44R mutation in the ADH1 gene sequence inserted into a YEp13 shuttle vector. These plasmids were propagated in E. coli, sequenced, and reintroduced into a yeast strain expressing no ADH1 activity. The growth patterns on selective media were determined. As the mutation allows for growth in the presence of allyl alcohol, students make the connection between DNA sequence and protein function. Student performance was assessed with pre- and post-tests, with improvement observed across all learning objectives. In addition to meeting the learning outcomes, 98% of the students thought that this experience allowed them to see how the scientific process can encompass multiple techniques to answer a single question. Eighty-four percent of the students thought that this experience was more engaging than other lab experiences they have had. Our multi-week laboratory examining the phenotypic changes in yeast alcohol metabolism successfully developed students' understanding of the scientific process, knowledge of molecular techniques and the relationship of gene sequence to protein function in an engaging manner.

Project‐based (research‐driven) laboratory courses stimulate student involvement, improve critical thinking and initiate cooperative learning. To this end, a 7‐week laboratory project was designed for a sophomore cell biology course to reinforce the fundamental relationship between genotype and phenotype using yeast alcohol dehydrogenase I (ADH1). Working in pairs, students used site‐directed mutagenesis to create a H44R mutation in the ADH1 gene sequence inserted into a YEp13 shuttle vector. These plasmids were propagated in E. coli, sequenced, and reintroduced into a yeast strain expressing no ADH1 activity. The growth patterns on selective media were determined. As the mutation allows for growth in the presence of allyl alcohol, students make the connection between DNA sequence and protein function. Student performance was assessed with pre‐ and post‐tests, with improvement observed across all learning objectives. In addition to meeting the learning outcomes, 98% of the students thought that this experience allowed them to see how the scientific process can encompass multiple techniques to answer a single question. Eighty‐four percent of the students thought that this experience was more engaging than other lab experiences they have had. Our multi‐week laboratory examining the phenotypic changes in yeast alcohol metabolism successfully developed students' understanding of the scientific process, knowledge of molecular techniques and the relationship of gene sequence to protein function in an engaging manner. [ABSTRACT FROM AUTHOR]

The higher frequency of lung adenocarcinoma in women smokers than in men smokers suggests a role for gender-dependent factors in the etiology of lung cancer. We evaluated estrogen receptor (ER) alpha and beta expression and activity in human lung adenocarcinoma cell lines and normal lung fibroblasts. Full-length ERalpha and ERbeta proteins were expressed in all cell lines with higher ERbeta than ERalpha. Although estradiol (E(2)) binding was similar, E(2) stimulated proliferation only in cells from females, and this response was inhibited by anti-estrogens 4-hydroxytamoxifen (4-OHT) and ICI 182,780. In contrast, E(2) did not stimulate replication of lung adenocarcinoma cells from males and 4-OHT or ICI did not block cell proliferation. Similarly, transcription of an estrogen response element-driven reporter gene was stimulated by E(2) in lung adenocarcinoma cells from females, but not males. Progesterone receptor (PR) expression was increased by E(2) in two out of five adenocarcinoma cell lines from females, but none from males. E(2) decreased E-cadherin protein expression in some of the cell lines from females, as it did in MCF-7 breast cancer cells, but not in the cell lines from males. Thus, ERalpha and ERbeta expression does not correlate with the effect of ER ligands on cellular activities in lung adenocarcinoma cells. On the other hand, coactivator DRIP205 expression was higher in lung adenocarcinoma cells from females versus males and higher in adenocarcinoma cells than in normal human bronchial epithelial cells. DRIP205 and other ER coregulators may contribute to differences in estrogen responsiveness between lung adenocarcinoma cells in females and males.

Background: Ethacrynic acid (ECA), a diuretic that has several cellular actions, increases expression of the sodium and potassium-activated adenosine triphosphatase (Na, K-ATPase or Na pump) in normal lymphocytes, but not in lymphocytes of bipolar patients. While this has been proposed to be important in the pathophysiology of bipolar illness, the response of neural tissues to ECA is unknown., Methods: Human neuroblastoma SH-SY5Y cells differentiated with 10-microM retinoic acid were treated with various ECA concentrations for 3 days, and changes in Na-pump alpha-isoform expression were quantified with densitometric analysis of Western bands., Results: Expression of alpha1 and alpha3 Na pump isoforms significantly increased with 10-5 M ECA. Cells treated with 10-6 or 10-7 M ECA showed no change in Na-pump expression, while cells treated with 10-4 M ECA died. The alpha2 isoform could not be detected in differentiated SH-SY5Y cells., Conclusions: The effect of ECA on alpha1-isoform in neural tissue is similar to that observed in lymphocytes. As alpha3 isoform is not expressed in lymphocytes, however, we conclude that lymphocytes are an incomplete model of neural tissue.