Queen's Science Undergraduate Research Journal https://ojs.library.queensu.ca/index.php/qsurj <p>The Queen’s Science Undergraduate Research Journal (QSURJ) is an online peer- reviewed and faculty-reviewed undergraduate research journal with a focus in biochemistry and life sciences.</p> The Arts and Science Undergraduate Society en-US Queen's Science Undergraduate Research Journal <h3><span style="font-size: 9pt;">Authors who publish with this journal agree to the following terms: </span></h3><ol><li><span style="font-size: 9pt;">Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.</span></li><li><span style="font-size: 9pt;">Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.</span></li><li><span style="font-size: 9pt;">Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work.</span></li></ol> Comparison of the inhibition of recombinant and native heme oxygenase-1 (HO-1) activity by the imidazoledioxolane compound QC-15 https://ojs.library.queensu.ca/index.php/qsurj/article/view/6569 Recombinant full-length and truncated forms of human heme oxygenase-1 (hHO-1) were compared with their native, microsomal HO-1 counterpart from rat spleen tissue, with respect to their inhibition by the imidazole-dioxolane HO inhibitor QC-15. Rat native HO-1 was maximally inhibited to the greatest extent (7.53 ± 1.51% of control activity), as compared to recombinant, full-length hHO-1 (55.55 ± 6.08%), and also truncated hHO-1 (72.17 ± 5.94%). The greater susceptibility of native HO-1 to QC-15 inhibition may be attributed to the presence of its C-terminal transmembrane domain (CTD) and its anchoring into the endoplasmic reticulum (ER). If so, membrane-anchored, recombinant, full-length hHO-1 may replace the current HO-1 microsomal model derived from rat spleen, in future in vitro inhibition studies. A better understanding of HO-1 inhibitors like QC-15 may lead to chemotherapeutics that prevent tumour cells from taking advantage of the cytoprotective nature of the HO system. Nick Stone ##submission.copyrightStatement## 1 Assessing accuracy of automated segmentation methods for brain lateral ventricles in MRI data https://ojs.library.queensu.ca/index.php/qsurj/article/view/6571 The incidence of Alzheimer’s disease (AD) has steadily increased over the last few decades. AD leads to a decreased quality of life for those affected, hence, there is an urgent need to identify a reference point that can assist in early identification of the presence of AD. An objective and sensitive measure that may assist in the detection of AD is the lateral ventricle volume. In high-resolution magnetic resonance (MR) images, a relationship between lateral ventricle enlargement and AD progression can be examined. Volumetric data analyses for the ventricles require that they be segmented by neuro-anatomy experts using manual tracing. Since manual segmentation methods are impractical due to time requirements and rater variability, automated methods are frequently used to reliably and accurately segment brain regions. Thus, our goal was to compare the performance of two automated segmentation methods, FreeSurfer (FS) and FreeSurfer combined with Large Deformation Diffeomorphic Metric Mapping label propagation (FS+LDDMM), for the task of lateral ventricle segmentation. The Dice Similarity Coefficient (DSC) was used to evaluate the segmentation accuracy obtained by these two automated methods. When compared to the manual segmentation labels, the FS+LDDMM method had a greater mean DSC than the FreeSurfer method. Moreover, the manual vs. FS+LDDMM DSC values ranged from 99-100, while manual vs. FreeSurfer ranged from 73-92. Both of these results illustrate that FS+LDDMM is an automated method that has a high degree of accuracy and can be used in place of manual segmentation, while FreeSurfer should only be used as a preliminary automatic segmentation method. Mahadev Bhalla Haaris Mahmood ##submission.copyrightStatement## 1 The putative type I secretion sequence of a 1.5-MDa icebinding adhesin folds as a Ca2+-dependent β-rich structure https://ojs.library.queensu.ca/index.php/qsurj/article/view/6570 Marinomonas primoryensis is a Gram-negative and strictly aerobic bacterium, an isolate of which was found in a brackish (half-strength seawater) lake in Antarctica. M. primoryensis produces a Ca2+-dependent 1.5-MDa ice-binding adhesin (MpAFP) that likely binds the bacterium to the underside of surface ice, where it may have better access to oxygen and other nutrients. The MpAFP is divided into five distinct regions that include the highly repetitive Region II (RII) and the moderately repetitive ice-binding Region IV (RIV). Region V (RV) is the C-terminal domain of MpAFP, and may serve as its non-cleavable signal sequence for the Type I Secretion System (TISS). The Protein Homology/analogY Recognition Engine (Phyre2) Server modeled RV as a Ca2+-bound β-rich structure. A previous study used a RV construct that started directly following the C-terminus of RIV, but the expressed protein aggregated and was unsuitable for further characterization. Here, we report the expression and purification of a fusion construct spanning RIV and RV. We defined the start of the RV domain by digesting the purified RIV-V fusion protein with trypsin in the presence of Ca2+. A soluble RV was then purified from the digestion mixture using anion-exchange chromatography, and its N-terminal residues were determined using Edman degradation sequencing. The folding of the newly designed RV construct was assessed by size-exclusion chromatography and circular dichroism (CD) spectroscopy. This work will provide insight into the structural relationship between RIV and RV, as well as how extremely large proteins are secreted via the TISS in Gram-negative bacteria. Tony He ##submission.copyrightStatement## 1