Biological degradation rates of estrogen compounds and common pharmaceutical and personal care products (PPCPs) were examined in soils with a long history of exposure to these compounds through wastewater effluent and in soil not previously exposed. Biological degradation rates over 14 days were compared under aerobic and anaerobic conditions. Estrogen compounds including estrone, 17β-estradiol, estriol, and 17α-ethinylestradiol exhibited rapid degradation by soil microorganisms in both aerobic and anaerobic conditions. Rapid degradation rates for estrone, estriol, and 17α-ethinylestradiol occurred in pre-exposed soil under aerobic conditions; half-lives calculated under these conditions were 0.6, 0.7, and 0.8 day, respectively. Unexposed soil showed similar or slightly longer halflives than pre-exposed soil under aerobic conditions. The exception was 17β-estradiol; in all treatments, degradation in unexposed soil resulted in a shorter halflife (2.1 versus 2.3 days). Anaerobic soils exhibited high biological degradation of estrogens as well. Half-lives of all estrogens ranged from 0.7 to 6.3 days in anaerobic soils. Triclosan degraded faster under aerobic conditions with half-lives of 5.9 and 8.9 days in exposed and unexposed soil. Under anaerobic conditions, triclosan half-lives were 15.3 days in unexposed and 28.8 days in exposed soil. Ibuprofen showed the least propensity toward biological degradation than other chemicals tested. Biological degradation of ibuprofen was only observed in unexposed soil; a half-life of 41.2 days was determined under anaerobic conditions and 121.9 days under aerobic conditions. Interestingly, unexposed soil exhibited a greater ability under anaerobic conditions to biologically degrade tested compounds than previously exposed soil.

Specific functions served by the various Na+-K+-ATPase α-isoforms are likely to originate in regions of structural divergence within their primary structures. The isoforms are nearly identical, with the exception of the NH2 terminus and a 10-residue region near the center of each molecule (isoform-specific region; ISR). Although the NH2 terminus has been clearly identified as a source of isoform functional diversity, other regions seem to be involved. We investigated whether the central ISR could also contribute to isoform variability. We constructed chimeric molecules in which the central ISRs of rat α1- and α2-isoforms were exchanged. After stable transfection into opossum kidney cells, the chimeras were characterized for two properties known to differ dramatically among the isoforms: their K+ deocclusion pattern and their response to PKC activation. Comparisons with rat full-length α1- and α2-isoforms expressed under the same conditions suggest an involvement of the central ISR in the response to PKC but not in K+ deocclusion.

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Biological degradation rates of six pharmaceuticals and personal care products were examined in soil from a land application site and in adjacent soil with no prior history of effluent exposure. Microbial degradation rates were compared over 2 weeks under standing water or saturated conditions and draining conditions after having been saturated for 3 days. Biological degradation of 17β-estradiol exhibited rapid rates of biological degradation under both saturated and draining conditions. Half-lives for 17β-estradiol ranged from 1.5 to 4 days; 66-97% was lost from the soils. Estriol showed a pattern of biological degradation in both saturated and draining conditions though the half-lives were longer (8.7-25.9 days) than those observed for 17β-estradiol. Twenty-eight percent to 73% of estriol was lost over the 14 days treatment period. Estrone and 17α-ethinylestradiol exhibited slower rates of biological transformation under saturated and draining conditions. Half-lives for estrone ranged between 27.5 and 56.8 days with loss of at most 21%. 17α-ethinylestradiol exhibited half-lives of 22.6-207 days. Half-life data for ibuprofen ranged from 30.4 to 1,706.4 days in this experiment. Losses of up to 17% were observed in draining soils. Triclosan loss was at most 10%, and half-lives were 70.9-398.8 days. In all cases, soils that were draining from saturated conditions exhibited faster degradation rates than soils that remained saturated. Prior exposure of the soil to effluent did not always result in higher biological degradation rates.

This empirical study is intended to assess whether a standards-based integrated teacher preparation curriculum is more beneficial in developing professional competencies than a traditional course-oriented curriculum at a college of education in a state university. Using multivariate analysis of variance, we found that students who went through the new integrated curriculum reported higher levels of professional preparation in all 13 standards and competency areas than those who went through the traditional course-oriented curriculum. This finding remained strong even when the teaching majors were included and controlled as another factor variable. Students in the integrated curriculum and those in the traditional curriculum had comparable characteristics, high school grade point averages (GPAs), and college GPAs. Additional related findings and suggestions for future studies also emerged.

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Comparisons of the primary structures of the Na,K-ATPase R-isoforms reveal the existence of regions of structural divergence, suggesting that they are involved in unique functions. One of these regions is the isoform-specific region (ISR), located near the ATP binding site in the major cytoplasmic loop. To evaluate its importance, we constructed mutants of the rodent wild-type R1 and R3 isoforms in which the ISR was replaced with irrelevant sequences, i.e., the analogous region from the rat gastric H,K-ATPase catalytic subunit or a region from the human c-myc oncogene. Opossum kidney (OK) cells were transfected with wild-type rat R1, R3, or their corresponding chimeras and selected in ouabain. Introduction of either mutant produced ouabain-resistant colonies, consistent with functional expression of the chimeric protein and indicating that the ISR is not essential for overall Na,K-ATPase function. The introduced chimeras were then characterized enzymatically by measuring the relative rate of K + and Li + deocclusions. Results showed that exchanges of both R1 and R3 ISRs significantly modified the sensitivity for the enzyme to either K + or Li + . Subsequent treatment of the cells with phorbol esters revealed an altered Na,K-ATPase transport in response to protein kinase C activation for the R1 chimeras. No changes were observed for the R3 isoform, suggesting that it is not sensitive to PKC regulation. These results demonstrated that the ISR plays an important role in ion deocclusion and in the response to PKC (only for the R1 isoform).The Na,K-ATPase, which catalyzes the extrusion of Na + and the absorption of K + at the expense of metabolic energy derived from ATP, consists of at least two subunits, R (110 kDa) and (55 kDa), existing as several isoforms. The R subunit, representing the catalytic component of the enzyme, is a membrane-spanning protein expressed as four isoforms (R1, R2, R3, and R4) with differences in enzyme kinetics and response to second messengers (1). Comparisons of the primary structures of the rat isoforms have revealed regions of structural divergence that could be involved in isoformspecific functions. A major site of sequence divergence among the R isoforms is the isoform-specific region (ISR 1 ; Figure 1) (2). This 11-amino acid sequence is located in the major cytoplasmic loop between TM4 and TM5 near the ATP binding site (2). Alignment and homology comparison of the rat R ISR amino acid sequences (Figure 1) reveal significant diversity among the isoforms. Indeed, while the rat R1 ISR shares 27% of homology with the R4 ISR, the R1 and R2 ISRs, as well as the R1 and R3 ISRs, share only 9% of their residues.Because of its proximity to the ATP binding site, we speculated that the replacement of the ISR by unrelated sequences would alter the enzymatic properties of the molecule. In a previous study, we have shown that the R1 ISR is essential in protein kinase C (PKC) regulation (2). The present study aims to investigate further the importance of the Na,K-ATPase R1 ISR and to des...