Lessons learned from designing a curriculum analytics tool for improving student learning and program quality.

Curriculum Analytics (CA) emerged as a sub-field of Learning Analytics, aiming to use large amounts of educational data to drive curriculum decision-making and program improvement. However, it is still an open question how the use of CA tools impacts student learning and program quality. To advance this field, this paper describes the lessons learned from having designed and implemented a CA tool to help managers and teaching staff reflect on curriculum and teaching practices. This CA tool was developed under a design-based research approach called The Integrative Learning Design Framework. We implemented a two-cycle building-testing structure to evaluate the perceived usefulness and usability of this tool. The first cycle consisted of designing a first version of the tool and evaluating its use throughout a case study involving 5 managers and 124 teaching staff members who participated in a 3-year continuous improvement process in one Latin American university. The second cycle consisted of redesigning the tool according to the lessons learned during the first cycle and evaluating its use throughout workshops with 16 managers and 9 teaching staff members in two Latin American universities. Findings indicate that the CA tool helped teachers collect a greater number and variety of evidence regarding students' attainment of competencies, allowing staff to be more aware of the learning situation of their students when redesigning course assessment methods and course sequences. Currently, this CA tool is being used by 20 Latin American universities, guiding curriculum renewal strategies beyond the current global pandemic. Supplementary Information: The online version contains supplementary material available at 10.1007/s12528-022-09315-4.

Query-guided protein-protein interaction inhibitor discovery.

Protein-protein interactions (PPIs) are central to biological mechanisms, and can serve as compelling targets for drug discovery. Yet, the discovery of small molecule inhibitors of PPIs remains challenging given the large and typically shallow topography of the interacting protein surfaces. Here, we describe a general approach to the discovery of orthosteric PPI inhibitors that mimic specific secondary protein structures. Initially, hot residues at protein-protein interfaces are identified in silico or from experimental data, and incorporated into secondary structure-based queries. Virtual libraries of small molecules are then shape-matched against the queries, and promising ligands docked to target proteins. The approach is exemplified experimentally using two unrelated PPIs that are mediated by an α-helix (p53/hDM2) and a ß-strand (GKAP/SHANK1-PDZ). In each case, selective PPI inhibitors are discovered with low µM activity as determined by a combination of fluorescence anisotropy and 1H-15N HSQC experiments. In addition, hit expansion yields a series of PPI inhibitors with defined structure-activity relationships. It is envisaged that the generality of the approach will enable discovery of inhibitors of a wide range of unrelated secondary structure-mediated PPIs.

Identification of ß-strand mediated protein-protein interaction inhibitors using ligand-directed fragment ligation.

ß-Strand mediated protein-protein interactions (PPIs) represent underexploited targets for chemical probe development despite representing a significant proportion of known and therapeutically relevant PPI targets. ß-Strand mimicry is challenging given that both amino acid side-chains and backbone hydrogen-bonds are typically required for molecular recognition, yet these are oriented along perpendicular vectors. This paper describes an alternative approach, using GKAP/SHANK1 PDZ as a model and dynamic ligation screening to identify small-molecule replacements for tranches of peptide sequence. A peptide truncation of GKAP functionalized at the N- and C-termini with acylhydrazone groups was used as an anchor. Reversible acylhydrazone bond exchange with a library of aldehyde fragments in the presence of the protein as template and in situ screening using a fluorescence anisotropy (FA) assay identified peptide hybrid hits with comparable affinity to the GKAP peptide binding sequence. Identified hits were validated using FA, ITC, NMR and X-ray crystallography to confirm selective inhibition of the target PDZ-mediated PPI and mode of binding. These analyses together with molecular dynamics simulations demonstrated the ligands make transient interactions with an unoccupied basic patch through electrostatic interactions, establishing proof-of-concept that this unbiased approach to ligand discovery represents a powerful addition to the armory of tools that can be used to identify PPI modulators.

Surface topology evolution of Trypanosoma trans-sialidase.

The trans-sialidase (TS) from Trypanosoma cruzi is a multifunctional protein given by its enzymatic activity and binding properties. The complex structure of TS promotes topology changes over the protozoa's surface with dramatic consequences for its biology. Detailed sequence analyses show that the evolution of TS in T. cruzi and other trypanosomes as well as its genomic organization is even more complex than it has been supposed before. All of these aspects are still neglected when TS is selected as a target for drug design and chemotherapy of Chagas' disease. Herein these aspects are discussed in the context of TS multifunctionality and dynamics drug design.

¿Dónde está el apéndice cecal? Enfoque anatómico con tomografía computarizada multidetector / Where is the appendix located? Anatomical approach with multidetector computed tomography

La apendicitis aguda representa aproximadamente un tercio de las causas de dolor abdominal agudo en los pacientes que acuden al servicio de urgencias. La integración gradual de la tomografía computarizada (TC) en el algoritmo diagnóstico ha reducido las tasas de falsos negativos en las apendicectomías al 1,7 % en general, y al 7 % en las mujeres. La TC ha demostrado ser el método de elección en el diagnóstico de apendicitis aguda, con exactitud entre el 93 y el 99 %. Aunque existe una localización frecuente del apéndice, se han descrito múltiples localizaciones posibles, lo cual clínicamente dificultad el diagnóstico de patología apendicular aguda, por lo cual es de vital importancia que los radiólogos estén familiarizados con esta anatomía para disminuir el número de falsos negativos en estos pacientes.

About one third of acute abdominal pain cases which admitted to the emergency department refer to acute appendicitis. The gradual integration of computed tomography (CT) in the diagnostic algorithm has reduced the rate of false negative appendectomies to 1.7% in general cases, and 7% in women. CT has proven to be the method of choice in the diagnosis of acute appendicitis, with an accuracy of between 93 and 99%. Even though the appendix has a common location, other locations do exist. This causes clinical difficulties in the diagnosis of appendix disease. Therefore, it is vitally important that radiologists are familiar with the anatomy of the appendix in order to decrease the number of false negatives in these patients.

Secondary structure of short ß-peptides as the chiral expression of monomeric building units: a rational and predictive model.

Chirality of the monomeric residues controls and determines the prevalent folding of small oligopeptides (from di- to tetramers) composed of 2-aminocyclobutane-1-carboxylic acid (ACBA) derivatives with the same or different absolute and relative configuration. The cis-form of the monomeric ACBA gives rise to two conformers, namely, Z6 and Z8, while the trans-form manifests uniquely as an H8 structure. By combining these subunits in oligo- and polypeptides, their local structural preference remains, thus allowing the rational design of new short foldamers. A lego-type molecular architecture evolves; the overall look depends only on the conformational properties of the structural building units. A versatile and efficient method to predict the backbone folds of designed cyclobutane ß-peptides is based on QM calculations. Predictions are corroborated by high-resolution NMR studies on selected stereoisomers, most of them being new foldamers that have been synthesized and characterized for the first time. Thus, the chiral expression of monomeric building units results in the defined secondary structures of small oligomers. As a result of this study, a new set of chirality controlled foldamers is provided to probe as biocompatible biopolymers.

Designing hybrid foldamers: the effect on the peptide conformational bias of ß- versus α- and γ-linear residues in alternation with (1R,2S)-2-aminocyclobutane-1-carboxylic acid.

Several oligomers constructed with (1R,2S)-2-aminocyclobutane-1-carboxylic acid and glycine, ß-alanine, and γ-amino butyric acid (GABA), respectively, joined in alternation have been synthesized and studied by means of NMR and CD experiments as well as with computational calculations. Results account for the spacer length effect on folding and show that conformational preference for these hybrid peptides can be tuned from ß-sheet-like folding for those containing a C(2) or C(4) linear segment to a helical folding for those with a C(3) spacer between cyclobutane residues. The introduction of cyclic spacers between these residues does not modify the extended ribbon-type structure previously manifested in poly(cis-cyclobutane) ß-oligomers.

Expression of trypomastigote trans-sialidase in metacyclic forms of Trypanosoma cruzi increases parasite escape from its parasitophorous vacuole.

Trypanosoma cruzi actively invades mammalian cells by forming parasitophorous vacuoles (PVs). After entry, the parasite has to escape from these vacuoles in order to replicate inside the host cell cytosol. Trans-sialidase (TS), a parasite enzyme that is used to obtain sialic acid from host glycoconjugates, has been implicated in cell invasion and PV exit, but how the enzyme acts in these processes is still unknown. Here we show that trypomastigotes derived from infected mammalian cells express and release 20 times more TS activity than axenic metacyclic trypomastigotes, which correspond to the infective forms derived from the insect vector. Both forms have the same capacity to invade mammalian cells, but cell derived trypomastigotes exit earlier from the vacuole. To test whether high TS expression is responsible for this increased exit from the PV, trypomastigote TS was expressed on the surface of metacyclic forms. Transfected and non-transfected metacyclics attached to and invaded HeLa or CHO cells equally. In contrast, metacyclics expressing TS on the surface escaped earlier from the vacuole than non-transfected metacyclics, or metacyclics expressing TS in their cytoplasm. Sialic acid may act as a barrier, which is removed by surface and/or secreted TS, because all types of parasites escaped earlier from the vacuoles of sialic acid-deficient Lec 2 cells than wild-type CHO cells. In addition, trypomastigotes and metacyclic forms expressing TS differentiated earlier into amastigotes. These results indicate that the increased expression of TS in cell-derived trypomastigotes is responsible for the earlier exit from the PV to the cytoplasm and their subsequent differentiation into amastigotes.

Da trans-sialidase e dos minicírculos de Trypanosoma cruzi à doença de Chagas / From the trans-sialidase and the minicircles of Trypanosama cruzi to Chagas disease

A doença de Chagas é causada pelo protozoário Kinetoplastidea Trypanosoma cruzi. O parasita inicia seu contato com o hospedeiro invadindo suas células para se reproduzir, podendo depois de algum tempo gerar uma patologia envolvendo processos imunológicos de natureza ainda pouco entendida. a T. cruzi entra ativamente em células de mamíferos formando o vacúolo parasitóforo, do qual deve escapar ao citoplasma para se replicar. Uma das moléculas envolvidas nestes processos é a enzima trans-sialidase. Esta enzima catalisa a transferência de ácido siálico de glicoconjugados dos hospedeiros para aceptores na superfície do parasita. Entretanto, não é conhecido como ela atua no processo de invasão. Nesta tese mostramos que a forma tripomastigota derivada de células de mamífero expressa e libera 20 vezes mais trans-sialidase que a forma metacíclica tripomastigota, que corresponde ao estágio do parasita derivado do inseto vetor. Ambas formas invadem células da mesma maneira, mas os tripomastigotas escapam mais rapidamente do vacúolo parasitóforo. Para testar se os níveis de trans-sialidase dos tripomastigotas derivados de célula são responsáveis pelo aumento de velocidade de escape, a trans-sialidase foi superexpressada em metacíclicos. A invasão de células ReLa não foi aumentada, porém os parasitas com altos níveis de trans-sialidase escaparam do vacúolo parasitóforo mais rapidamente que os parasitas que não super-expressavam a enzima. Em células CRa Lec-2, que são deficientes na incorporação de ácido siálico na superfície e interior dos lisossomos, todos os tipos de tripomastigotas escaparam com a mesma velocidade. Já as células CRa selvagens apresentaram a diferença de escape observada nas células ReLa. Estes resultados demonstram que o ácido siálico é uma barreira ao escape do parasita para o citoplasma e que a função da trans-sialidase é de...