The influence of personality and ability on undergraduate teamwork and team performance

The ability to work effectively on a team is highly valued by employers, and collaboration among students can lead to intrinsic motivation, increased persistence, and greater transferability of skills. Moreover, innovation often arises from multidisciplinary teamwork. The influence of personality and ability on undergraduate teamwork and performance is not comprehensively understood. An investigation was undertaken to explore correlations between team outcomes, personality measures and ability in an undergraduate population. Team outcomes included various self-, peer- and instructor ratings of skills, performance, and experience. Personality measures and ability involved the Five-Factor Model personality traits and GPA. Personality, GPA, and teamwork survey data, as well as instructor evaluations were collected from upper division team project courses in engineering, business, political science, and industrial design at a large public university. Characteristics of a multidisciplinary student team project were briefly examined. Personality, in terms of extraversion scores, was positively correlated with instructors’ assessment of team performance in terms of oral and written presentation scores, which is consistent with prior research. Other correlations to instructor-, students’ self- and peer-ratings were revealed and merit further study. The findings in this study can be used to understand important influences on successful teamwork, teamwork instruction and intervention and to understand the design of effective curricula in this area moving forward

Mifepristone Prevents Stress-Induced Apoptosis in Newborn Neurons and Increases AMPA Receptor Expression in the Dentate Gyrus of C57/BL6 Mice

Chronic stress produces sustained elevation of corticosteroid levels, which is why it is considered one of the most potent negative regulators of adult hippocampal neurogenesis (AHN). Several mood disorders are accompanied by elevated glucocorticoid levels and have been linked to alterations in AHN, such as major depression (MD). Nevertheless, the mechanism by which acute stress affects the maturation of neural precursors in the dentate gyrus is poorly understood. We analyzed the survival and differentiation of 1 to 8 week-old cells in the dentate gyrus of female C57/BL6 mice following exposure to an acute stressor (the Porsolt or forced swimming test). Furthermore, we evaluated the effects of the glucocorticoid receptor (GR) antagonist mifepristone on the cell death induced by the Porsolt test. Forced swimming induced selective apoptotic cell death in 1 week-old cells, an effect that was abolished by pretreatment with mifepristone. Independent of its antagonism of GR, mifepristone also induced an increase in the percentage of 1 week-old cells that were AMPA+. We propose that the induction of AMPA receptor expression in immature cells may mediate the neuroprotective effects of mifepristone, in line with the proposed antidepressant effects of AMPA receptor potentiators

Streptokinase contains two independent plasminogen-binding sites

Streptokinase (SK) exerts its thrombolytic effect by activating plasminogen (PG) indirectly, after the formation of an equimolar complex with either PG or plasmin (PN). The location and nature of the PG/PN-binding sites in SK have been explored using limited proteolysis with immobilized trypsin. Employing Western blotting with radiolabeled PG after SDS-PAGE of total tryptic digest, three fragments of MW 7 kD, 19 kD and 31 kD were found to possess PG-binding ability. Each of these fragments was then isolated by reverse phase HPLC and characterised with respect to its sequence, as well as its PG-binding properties by ELISA. These analyses revealed that in addition to a PG-binding site in the region 143-293 reported recently in the literature, there is another distinct, high-affinity and independent PG-binding site, located in the N terminal region (residues 1-59) of SK. Using a synthetic peptide, the N-terminally located PG-binding-site has been further localised to the region 37-51 of SK. Further, we demonstrate that the PG-binding of this peptide is not mediated through the lysine-binding sites ("Kringles") of PG. This stretch contains a short sequence (LTSRPA) that is also present in the PG-binding domain of human fibronectin

Mapping of the plasminogen binding site of streptokinase with short synthetic peptides.

Although several recent studies employing various truncated fragments of streptokinase (SK) have demonstrated that the high-affinity interactions of this protein with human plasminogen (HPG) to form activator complex (SK-HPG) are located in the central region of SK, the exact location and nature of such HPG interacting site(s) is still unclear. In order to locate the "core" HPG binding ability in SK, we focused on the primary structure of a tryptic fragment of SK derived from the central region (SK143-293) that could bind as well as activate HPG, albeit at reduced levels in comparison to the activity of the native, full-length protein. Because this fragment was refractory to further controlled proteolysis, we took recourse to a synthetic peptide approach wherein the HPG interacting properties of 16 overlapping 20-mer peptides derived from this region of SK were examined systematically. Only four peptides from this set, viz., SK234-253, SK254-273, SK274-293, and SK263-282, together representing the contiguous sequence SK234-293, displayed HPG binding ability. This was established by a specific HPG-binding ELISA as well as by dot blot assay using 125I-labeled HPG. These results showed that the minimal sequence with HPG binding function resided between residues 234 and 293. None of the synthetic SK peptides was found to activate HPG, either individually or in combination, but, in competition experiments where each of the peptides was added prior to complex formation between SK and HPG, three of the HPG binding peptides (SK234-253, SK254-273, and SK274-293) inhibited strongly the generation of a functional activator complex by SK and HPG. This indicated that residues 234-293 in SK participate directly in intermolecular contact formation with HPG during the formation of the 1:1 SK-HPG complex. Two of the three peptides (SK234-253 and SK274-293), apart from interfering in SK-HPG complex formation, also showed inhibition of the amidolytic activity of free HPN by increasing the K(m) by approximately fivefold. A similar increase in K(m) for amidolysis by HPN as a result of complexation with SK has been interpreted previously to arise from the steric hinderance at or near the active site due to the binding of SK in this region. Thus, our results suggest that SK234-253 and SK274-293 also, like SK, bound close to the active site of HPN, an event that was reflected in the observed alteration in its substrate accessibility. By contrast, whereas the intervening peptide (SK254-273) could not inhibit amidolysis by free HPN, it showed a marked inhibition of the activation of "substrate" PG (human or bovine plasminogen) by activator complex, indicating that this particular region is intimately involved in interaction of the SK-HPG activator complex with substrate plasminogen during the catalytic cycle. This finding provides a rational explanation for one of the most intriguing aspects of SK action, i.e., the ability of the SK-HPG complex to catalyze selectively the activation of substrate molecules of PG to PN, whereas free HPN alone cannot do so. Taken together, the results presented in this paper strongly support a model of SK action in which the segment 234-293 of SK, by virtue of the epitopes present in residues 234-253 and 274-293, binds close to the active center of HPN (or, a cryptic active site, in the case of HPG) during the intermolecular association of the two proteins to form the equimolar activator complex; the segment SK254-273 present in the center of the core region then imparts an ability to the activator complex to interact selectively with substrate PG molecules during each PG activation cycle

Role of the amino-terminal region of streptokinase in the generation of a fully functional plasminogen activator complex probed with synthetic peptides.

The mechanism whereby fragments of streptokinase (SK) derived from its N terminus (e.g., SK1-59 or SK1-63) enhance the low plasminogen (PG)-activating ability of other fragments, namely SK64-386, SK60-414, SK60-387, and SK60-333 (reported previously), has been investigated using a synthetic peptide approach. The addition of either natural SK1-59, or chemically synthesized SK16-59, at saturation (about 500-fold molar excess) generated amidolytic and PG activation capabilities in equimolar mixtures of human plasminogen (HPG) and its complementary fragment (either SK60-414 or SK56-414, prepared by expression of truncated SK gene fragments in Escherichia coli) that were approximately 1.2- and 2.5-fold, respectively, of that generated by equimolar mixtures of native SK and HPG. Although in the absence of SK1-59 equimolar mixtures of SK56-414 and HPG could generate almost 80% of amidolytic activity, albeit slowly, less than 2% level of PG activation could be observed under the same conditions, indicating that the contribution of the N-terminal region lay mainly in imparting in SK56-414 an enhanced ability for PG activation. The ability of various synthetic peptides derived from the amino-terminal region (SK16-51, SK16-45, SK37-59, SK1-36, SK16-36, and SK37-51) to (1) complement equimolar mixtures of SK56-414 and HPG for the generation of amidolytic and PG activation functions, (2) inhibit the potentiation of SK56-414 and HPG by SK16-59, and (3) directly inhibit PG activation by the 1:1 SK-HPG activator complex was tested. Apart from SK16-59, SK16-51, and 16-45, the ability to rapidly generate amidolytic potential in HPG in the presence of SK56-414 survived even in the smaller SK-peptides, viz., SK37-59 and SK37-51. However, this ability was abolished upon specifically mutating the sequence -LTSRP-, present at position 42-46 in native SK. Although SK16-51 retained virtually complete ability for potentiation of PG activation in comparison to SK16-59 or SK1-59, this ability was reduced by approximately fourfold in the case of SK16-45, and completely abolished upon further truncation of the C-terminal residues to SK16-36 or SK1-36. Remarkably, however, these peptides not only displayed ability to bind PG, but also showed strong inhibition of PG activation by the native activator complex in the micromolar range of concentration; the observed inhibition, however, could be competitively relieved by increasing the concentration of substrate PG in the reaction, suggesting that this region in SK contains a site directed specifically toward interaction with substrate PG. This conclusion was substantiated by the observation that the potentiation of PG activating ability was found to be considerably reduced in a peptide (SK25-59) in which the sequence corresponding to this putative locus (residues 16-36) was truncated at the middle. On the other hand, fragments SK37-51 and SK37-59 did not show any inhibition of the PG activation by native activator complex. Taken together, these findings strongly support a model of SK action wherein the HPG binding site resident in the region 37-51 helps in anchoring the N-terminal domain to the strong intermolecular complex formed between HPG and the region 60-414. In contrast, the site located between residues 16 and 36 is qualitatively more similar to the previously reported PG interacting site (SK254-273) present in the core region of SK, in being involved in the relatively low-affinity enzyme-substrate interactions of the activator complex with PG during the catalytic cycle

Inhibition of membrane depolarisation-induced transcriptional activity of cyclic AMP response element binding protein (CREB) by the dual-leucine-zipper-bearing kinase in a pancreatic islet beta cell line

The activation of the transcription factor cyclic AMP response element binding protein (CREB) by protein kinase A is inhibited by the human orthologue of the mitogen-activated protein kinase, dual-leucine-zipper-bearing kinase (DLK) in teratocarcinoma cells. However, pancreatic beta cells are electrically excitable and a major pathway regulating CREB in these cells is membrane depolarisation, leading to calcium influx and activation of the calcium/calmodulin-dependent protein phosphatase calcineurin. Therefore, the effect of DLK on CREB activity induced by membrane depolarisation was investigated in the beta cell line HIT.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46037/1/125_2005_Article_87.pd