Cultivating cultural capitals in introductory algebra-based physics through reflective journaling

At a large, diverse, hispanic-serving, master’s-granting university, the Alma Project was created to support the rich connections of life experiences of science, technology, engineering, and mathematics (STEM) students that come from racially diverse backgrounds through reflective journaling. Utilizing frameworks in ethnic studies and social psychology, the Alma Project aims to make learning STEM inclusive by affirming the intersectional identities and cultural wealth that students bring into STEM classrooms. Approximately once per month students who participate in the Alma Project spend 5–10 min at the beginning of class responding to questions designed to affirm their values and purpose for studying STEM in college. Students then spend time in class sharing their responses with their peers, to the extent that they feel comfortable, including common struggles and successes in navigating through college and STEM spaces. For this study, we analyze 180 reflective journaling essays of students enrolled in General Physics I, an algebra-based introductory physics course primarily for life science majors. Students were enrolled in a required lab, a self-selected community-based learning program (Supplemental Instruction), or in a small number of instances, both. Using the community cultural wealth framework to anchor our analysis, we identified 11 cultural capitals that students often expressed within these physics spaces. Students in both populations frequently expressed aspirational, attainment, and navigational capital, while expressions of other cultural capitals, such as social capital, differ in the two populations. Our findings suggest that students bring rich and diverse perspectives into physics classrooms when asked to reflect about their lived experiences. Moreover, our study provides evidence that reflective journaling can be used as an asset-based teaching tool. By using reflective journaling in physics spaces, recognizing students’ assets has the potential for physics educators to leverage students’ lived experiences, goals, and values to make physics learning more meaningful and engaging

Dissecting the Active Site of the Collagenolytic Cathepsin L3 Protease of the Invasive Stage of Fasciola hepatica

Background: A family of secreted cathepsin L proteases with differential activities is essential for host colonization and survival in the parasitic flatworm Fasciola hepatica. While the blood feeding adult secretes predominantly FheCL1, an enzyme with a strong preference for Leu at the S2 pocket of the active site, the infective stage produces FheCL3, a unique enzyme with collagenolytic activity that favours Pro at P2. Methodology/Principal Findings: Using a novel unbiased multiplex substrate profiling and mass spectrometry methodology (MSP-MS), we compared the preferences of FheCL1 and FheCL3 along the complete active site cleft and confirm that while the S2 imposes the greatest influence on substrate selectivity, preferences can be indicated on other active site subsites. Notably, we discovered that the activity of FheCL1 and FheCL3 enzymes is very different, sharing only 50% of the cleavage sites, supporting the idea of functional specialization. We generated variants of FheCL1 and FheCL3 with S2 and S3 residues by mutagenesis and evaluated their substrate specificity using positional scanning synthetic combinatorial libraries (PS-SCL). Besides the rare P2 Pro preference, FheCL3 showed a distinctive specificity at the S3 pocket, accommodating preferentially the small Gly residue. Both P2 Pro and P3 Gly preferences were strongly reduced when Trp67 of FheCL3 was replaced by Leu, rendering the enzyme incapable of digesting collagen. In contrast, the inverse Leu67Trp substitution in FheCL1 only slightly reduced its Leu preference and improved Pro acceptance in P2, but greatly increased accommodation of Gly at S3. Conclusions/Significance: These data reveal the significance of S2 and S3 interactions in substrate binding emphasizing the role for residue 67 in modulating both sites, providing a plausible explanation for the FheCL3 collagenolytic activity essential to host invasion. The unique specificity of FheCL3 could be exploited in the design of specific inhibitors selectively directed to specific infective stage parasite proteinases. © 2013 Corvo et al

Investigation of the Proteolytic Functions of an Expanded Cercarial Elastase Gene Family in Schistosoma mansoni

Schistosome parasites are a major cause of disease in the developing world. The larval stage of the parasite transitions between an intermediate snail host and a definitive human host in a dramatic fashion, burrowing out of the snail and subsequently penetrating human skin. This process is facilitated by secreted proteases. In Schistosoma mansoni, cercarial elastase is the predominant secreted protease and essential for host skin invasion. Genomic analysis reveals a greatly expanded cercarial elastase gene family in S. mansoni. Despite sequence divergence, SmCE isoforms show similar expression profiles throughout the S. mansoni life cycle and have largely similar substrate specificities, suggesting that the majority of protease isoforms are functionally redundant and therefore their expansion is an example of gene dosage. However, activity-based profiling also indicates that a subset of SmCE isoforms are activated prior to the parasite's exit from its intermediate snail host, suggesting that the protease may also have a role in this process

Use and perspectives of nitric oxide donors in agriculture

[Mini-review] Nitric oxide (NO) has emerged in the last 30 years as a key molecule involved in many physiological processes in plants, animals and bacteria. Current research has shown that NO can be delivered via donor molecules. In such cases, the NO release rate is dependent on the chemical structure of the donor itself and on the chemical environment. Despite NO's powerful signaling effect in plants and animals, the application of NO donors in agriculture is currently not implemented and research remains mainly at the experimental level. Technological development in the field of NO donors is rapidly expanding in scope to include controlling seed germination, plant development, ripening and increasing shelf-life of produce. Potential applications in animal production have also been identified. This concise review focuses on the use of donors that have shown potential biotechnological applications in agriculture. Insights are provided into (i) the role of donors in plant production, (ii) the potential use of donors in animal production and (iii) future approaches to explore the use and applications of donors for the benefit of agricultur

[Mn(bpb)(DMAP)(NO)], an {Mn-NO} nitrosyl with Z' = 8.

The structure of the title compound octa-kis-{[4-(dimethyl-amino)-pyridine](nitros-yl)[N,N'-(o-phenyl-ene)bis-(pyridine-2-carboxamidato)]manganese(II)} ethanol hepta-solvate 3.5-hydrate, [Mn(C(18)H(12)N(4)O(2))(C(7)H(10)N(2))(NO)](8)·7C(2)H(5)OH·3.5H(2)O, or 8[Mn(bpb)(DMAP)(NO)]·7EtOH·3.5H(2)O, is an unusual example of a structure with Z' = 8. The tetra-dentate bpb ligand, together with the nitrosyl and dimethyl-amino-pyridine ligands, gives rise to a distorted octa-hedral coordination environment for the Mn(II) ion. The average Mn-N((N=O)) bond length is 1.631 (13) Å. The eight mol-ecules in the asymmetric unit differ mainly in the rotation of the DMAP pyridine plane with respect to a reference plane of the Mn and three N atoms, one of which is the N atom of the NO group. The dihedral angles between the normals to these planes range from a minimum of 28.0 (2)° to a maximum of 64.2 (2)°. There are also some differences in O-H⋯O hydrogen bonding inter-actions. For example, of the sixteen C=O acceptors, there are seven different inter-actions with EtOH donors and two inter-actions with H(2)O donors. The crystal studied was found to be a two-component twin, with a 179.9° rotation about the real axis [-0.535, 0.004, 1.000]. Due to the presence of a superlattice and, consequently, the large number of weak reflections, the refinement utilized rigid solvate groups and isotropic displacement parameters for all except the Mn atoms. H atoms were not located for hydrate molecules

[Mn(bpb)(DMAP)(NO)], an {Mn–NO}6 nitrosyl with Z′ = 8

The structure of the title compound octakis{[4-(dimethylamino)pyridine](nitrosyl)[N,N′-(o-phenylene)bis(pyridine-2-carboxamidato)]manganese(II)} ethanol heptasolvate 3.5-hydrate, [Mn(C18H12N4O2)(C7H10N2)(NO)]8·7C2H5OH·3.5H2O, or 8[Mn(bpb)(DMAP)(NO)]·7EtOH·3.5H2O, is an unusual example of a structure with Z′ = 8. The tetradentate bpb ligand, together with the nitrosyl and dimethylaminopyridine ligands, gives rise to a distorted octahedral coordination environment for the Mn(II) ion. The average Mn—N(N=O) bond length is 1.631 (13) Å. The eight molecules in the asymmetric unit differ mainly in the rotation of the DMAP pyridine plane with respect to a reference plane of the Mn and three N atoms, one of which is the N atom of the NO group. The dihedral angles between the normals to these planes range from a minimum of 28.0 (2)° to a maximum of 64.2 (2)°. There are also some differences in O—H...O hydrogen bonding interactions. For example, of the sixteen C=O acceptors, there are seven different interactions with EtOH donors and two interactions with H2O donors. The crystal studied was found to be a two-component twin, with a 179.9° rotation about the real axis [−0.535, 0.004, 1.000]. Due to the presence of a superlattice and, consequently, the large number of weak reflections, the refinement utilized rigid solvate groups and isotropic displacement parameters for all except the Mn atoms. H atoms were not located for hydrate molecules