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Manipulation of microvillar proteins during Salmonella enterica invasion results in brush border effacement and actin remodeling
No full textEnterocyte invasion by the gastrointestinal pathogen Salmonella enterica is accompanied by loss of brush border and massive remodeling of the actin cytoskeleton, leading to microvilli effacement and formation of membrane ruffles. These manipulations are mediated by effector proteins translocated by the Salmonella Pathogenicity Island 1-encoded type III secretion system (SPI1- T3SS). To unravel the mechanisms of microvilli effacement and contribution of SPI1-T3SS effector proteins, the dynamics of host-pathogen interactions was analyzed using live cell imaging (LCI) of polarized epithelial cells (PEC) expressing LifeAct-GFP. PEC were infected with S. enterica wild-type and mutant strains with defined defects in SPI1-T3SS effector proteins, and pharmacological inhibition of actin assembly were applied. We identified that microvilli effacement involves two distinct mechanisms: i) F-actin depolymerization mediated by villin and ii), the consumption of cytoplasmic G-actin by formation of membrane ruffles. By analyzing the contribution of individual SPI1-T3SS effector proteins, we demonstrate that SopE dominantly triggers microvilli effacement and formation of membrane ruffles. Furthermore, SopE via Rac1 indirectly manipulates villin, which culminates in F-actin depolymerization. Collectively, these results indicate that SopE has dual functions during F-actin remodeling in PEC. While SopE-Rac1 triggers F-actin polymerization and ruffle formation, activation of PLCg and villin by SopE depolymerizes F-actin in PEC. These results demonstrate the key role of SopE in destruction of the intestinal barrier during intestinal infection by Salmonella.This work was supported by the Deutsche Forschungsgemeinschaft
grants P4 and Z within the collaborative research center SFB 944. AFL
was supported by a research fellowship of the German Academic
Exchange Service (DAAD/A-0773175). Mutant strains SB161, SB225,
SB856 and M712 were kindly provided by Wolf-Dietrich Hardt,
ETH Zürich.Facultyye
Examining native Saskatchewan bumble bees health using species occurrence data, pathogen incidence and gut microbial associations
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Biology, University of Regina. xv, 213 p.Bees are important pollinators, though, recent evidence suggests some species
of bumble bees (Hymenoptera, Apidae, Bombini, Bombus Latreille) are declining in
parts of their ranges due to a combination of drivers such as climate change, pesticide
use, habitat loss, competition for resources and pathogens acting upon the bees at
once. A relatively new and important area of gut microbial research, the fungal and
bacterial gut community members, could offer insight on why some species of bumble
bees are declining while others remain stable. In this thesis, I use a combination of field
and molecular methods to investigate aspects of bumble bee health in Saskatchewan,
Canada, including species occurrence and pathogen incidence and explore microbial
associations with known and potential pathogens.
The second chapter explores the need for a bumble bee monitoring program in
Saskatchewan and how standardization compares to non-standardized survey
methods. I compared bumble bee occurrence data from four datasets in terms of
sampling effort over time and how properties of each dataset influenced species
conservation assessments. The Palmier dataset was a single collection event in 2018
using a standardized survey methods. The Royal Saskatchewan Museum (RSM) and
Global Biodiversity Information Facility (GBIF) datasets represented specimens
collected with unstandardized collection events over decades. The iNaturalist dataset
contained citizen science observations. The Palmier dataset was the largest of the four
datasets and despite the single collection event, species richness in the Palmier dataset
was comparable to the RSM and GBIF datasets. The iNaturalist dataset was biased to
locations with higher population density and overrepresented species at-risk compared
to the Palmier, RSM and GBIF datasets.
The third chapter (previously published) documents the first occurrences of the
Common Eastern Bumble Bee (B. impatiens), a managed species that is not native to
the Canadian prairies, recorded from southeastern Alberta. The fourth chapter (also
previously published) documents the first Canadian occurrence of a recently
characterized trypanosomatid bumble bee pathogen, Crithidia expoeki, in native
Saskatchewan bumble bees.
The fifth chapter explores the fungal and bacterial gut communities of bumble
bees and their associations with common bee pathogens. The results indicate that
pathogens cause dysbiosis, or imbalance of microbial communities in bumble bees. A
differential abundance analysis revealed significantly enriched and depleted taxa in
bees testing positive for specific pathogens. The results from this study can be used to
compare microbial strain level differences across geographic landscapes over time.
The sixth chapter investigates a novel yeast association and swollen
proventriculus in the digestive tract of at-risk bumble bee species across Canada. It was
discovered that the swollen proventriculus morphology occurred only in males in the
subgenus Bombus, a taxon in which the majority of North American species are at-risk.
Classic culturing methods and Sanger sequencing revealed that bumble bees with a
swollen proventriculus harboured distinct yeast communities in high numbers. Using
16S rRNA sequencing, I also found higher abundances of lactic acid bacteria and
Gillimella bacteria in male bumble bees with a swollen proventriculus compared to
bumble bees of both sexes without.Studentye
Analyzing the effectiveness of Covid-19 vaccines among different age groups using multinomial logistic regression model
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Science in Statistics, University of Regina. vii, 95 p.This study is conducted to evaluate the effectiveness of Covid-19 vaccines
in different age groups in Saskatchewan, Canada. Data was collected between
September 2021 and December 2021, and a statistical method called
multinomial logistic regression was used to analyze the relationships between
multiple categorical variables. In this study, the categorical variables were
the age groups and the vaccination status (fully vaccinated cases, partially
vaccinated cases, and unvaccinated cases) of the individuals with the interaction
effect of rate of cases. The mathematical proof for the multinomial
logistic regression model with interaction effect was derived in this study. The
study demonstrated the effectiveness of Covid-19 vaccines among vaccinated
age groups and provided theory and practical application of the multinomial
logistic regression model. Results show that there is a statistically significant
impact of age group and vaccination status on the effectiveness of Covid-19
cases in Saskatchewan. Specifically, there is a difference in vaccine effectiveness
based on age groups and vaccination status. The findings of this
study provide crucial insights for policymakers and public health officials to
optimize vaccination rollout strategies and control the spread of Covid-19.
Overall, this study represents an important step in the ongoing efforts to understand
the effectiveness of Covid-19 vaccines and to develop policies and
interventions that can help mitigate the pandemic impact.Studentye
Working with Child Victims During the COVID-19 Pandemic: A Qualitative Study of Child Maltreatment Investigators’ Experiences
No full textThe present study adds to the growing body of knowledge on the impact of the COVID-19 pandemic by examining the experiences of Canadian child maltreatment investigators. Three focus groups were conducted with child maltreatment investigators (n = 16) from across Canada to investigate the impact of COVID-19 on child maltreatment investigators and the children and families they work with. Findings from this qualitative study relate to the personal and professional impact of COVID-19 on child maltreatment investigators and the impact of COVID-19 on investigators’ work practices. Subthemes relating to the impact of COVID-19 on child maltreatment investigators include fatigue, stress, and burnout; self-care and isolation; working from home with increasing workloads; child maltreatment investigators as essential workers; and workplace support. Participants’ work practices were impacted by rates of reporting throughout the pandemic, reduced in-person contact with clients, remote services and communication, and COVID-related safety protocols and challenges. Recommendations stemming from these focus groups include the recognition of child maltreatment investigators as essential workers, access to adequate counseling services for child maltreatment investigators, workplace flexibility for child maltreatment investigators, and ensuring that child protection agencies are adequately resourced to maintain manageable workloads.This project was funded by a Social Sciences and Humanities Research Council of Canada Partnership Engage Grant
Evaluating and optimizing the performance of single and blended amines based on their chemical structures for carbon dioxide capture from industrial gas streams
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Process Systems Engineering, University of Regina. ix, 121 p.With the well-known fact on negatively impact of the human activities and the tremendously growth of industrial sectors and the increase in the global energy demand, the increase of the Green House Gas (GHG) including CO2 is very central because almost all fossil fuel activities lead to generation of this environmentally harmful GHG which found to cause increasing on the average global temperature which causing several major issues such as extreme weather conditions, heat waves, sea level rise, wild fires, health problems and many more. Actions are required immediately to reduce the emission such as using alternative energy source with less GHG emission and use Carbon Capture and Sequestration (CCS). Post combustion capture by using a liquid absorbent solution is successful method specially the ability to regenerate the solution which makes this method cost sufficient for industrial applications. The scientists are still looking for perfect fit solution in both performance and management’s levels. This research is focused on finding a good solution that has high absorption-desorption performance and has lower corrosion rate, foaming and degradation. The relation between the performance and the chemical structure, finding the optimum condition of the single amine solutions and the blend ratio for best performance were also studied. However, two sets of amines studied mono amines and diamines. In the diamine set, the ethanol was added to the nitrogen atom in the structure while in the monoamine, the alkyl group was added to the structure. The desorption and absorption parameters criteria were used for selecting components of amine blend. The concentration and the ratio of the blend components varied in order to find the optimum ratio and concentration. The optimum blend and its single components were then studied for corrosion, foaming and degradation. The results of screening of 4AB and 4A2MB showed that adding methyl group to the straight chain enhance the absorption and the desorption performance while reduce the heat duty. The study of the diamines 22AEE and BMEM showed adding 3 methyl group sto the nitrogen atoms in the structure reduced the absorption and desorption performance and increased the heat duty, while in 22AEE and EDA; adding the -OH group to EDA as seen in 22AEE increased the rich loading, desorption rate and cyclic capacity while absorption rate, pKa, and heat duty reduced by adding the ethanol group to the structure. Considering –OH group in the structure increases the solubility of the amine and makes it less volatile which is preferred. However, the mass transfer limitations on all amines in this research had no impact on the performance at the concentrations used in the research. On the other hand, increasing the number of amine groups from mono to diamine caused to generate larger amounts of bicarbonate ions which lead to higher CO2 desorption rates and cyclic capacity, but lower heat duty. Also, the higher alkyl group found to have high viscosity. Adding ethanol groups to the diamine increased the viscosity in general but it had no impact on the performance. The developed criteria of blend selection of the diamine in terms of absorption parameter was based on taking the average pKa1 and pKa2 which resulted at the end in selection of the best performance fit of 22AEE:EDA (3:1) of overall 1M blend after screening several ratios and concentration. This had an outstanding desorption characteristics/heat duty as well as very good absorption characteristics. 22AEE to EDA 3:1 blend, implying that it is a good potential solvent for post combustion CO2 capture. Then, carried 3:1 blend for further management testing like (corrosion, foaming and degradation/emission). 22AEE found to have lower foaming than EDA and thus due to the existing three hydrophilic groups and higher surface tension compared to two groups in EDA structure. Corrosion found to be higher in EDA than 22AEE. The degradation rate found higher in 22AEE while the accumulated emission found higher in EDA.Studentye
Modeling of volumetric changes in cracked expansive soils
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Environmental Systems Engineering, University of Regina. xi, 150 p.Extensive damages to civil infrastructure occur due to volumetric deformations in expansive soils. Deformations in this class of sediments are affected by variations in soil properties, surface conditions, antecedent water, and meteorological parameters. Ground shifting is further aggravated by the presences of cracks originating from cycles of hydration-dehydration, freeze-thaw, and glacial advance-retreat. This research is focused on developing a clear understanding of modelling volumetric changes in cracked expansive soils. For this purpose, a representative expansive soil from Regina having a high water adsorption capacity (liquid limit of 77% and plastic limit of 27%) along with hairline cracks was characterized to provide baseline geotechnical properties.
The main contributions of this research are summarized as follows: (i) empirical models for volumetric changes in cracked expansive clays using three new fit equations to represent soil property functions, namely; bimodal water retention curve, bimodal hydraulic conductivity curve, and S-shaped swell-shrink curve; (ii) a numerical model for predicting weather-induced volumetric changes by coupling flow-through and heave-settlement while capturing for the effect of cracks on soil behavior; and (iii) a numerical-hierarchical risk model for infrastructure supported by cracked expansive soils by including surface conditions and climate parameters.
Results indicated that the average swell potential and swell pressure of the investigated clay were found to be 18 ± 2% and 155 ± 15 kPa, respectively. Likewise, heave was found to be 20 mm to 30 mm at surface and gradually diminishes at 1.75 m depth. History matching of numerical model revealed that the annual volumetric changes are ± 20 mm in water deficient years and reduce to half (± 10 mm) in water surplus years.
With respect to datum, the risk of volume changes was found to be two times higher in parks, insignificant for roads, half for five story buildings, and one-fourth for pipes under front road. Among meteorological parameters, initial water content representing antecedent condition and precipitation causing increase in water content were found to be the most critical. The findings and the contributions of this research are useful for improved initial design and long-term maintenance of buried and surface infrastructure in cracked expansive soils.Studentye
Qualitative Evaluation of Mental Health Capacity Building Pilot Project in Saskatchewan Schools
No full textSchool-based programs have been recommended as an effective way to tackle stigma and mental health burden among children and youth. As the Mental Health Capacity Building (MHCB) initiative was piloted across five Saskatchewan schools, this study sought to capture in-depth reflections from different stakeholders and provide experiential evidence of the initiative’s impacts. Semi-structured interviews were conducted with MHCB staff, teaching staff, student-leaders, and parents engaged in the initiative. A directed content analysis was used to synthesize the data and categorize them into four areas, further explained. The experiential evidence of the MHCB initiative showed improving mental health literacy, and positive emotional and social engagement for students (better health). The platform bridged the gap of care for some at-risk students in need of support or having difficulty reaching out (better care). The initiative inspired teacher integration of mental health programming into classrooms (better value) and created a wide network for mental health promotions (better teams). Overall, the MHCB initiative demonstrated encouraging evidence of improved mental health knowledge for engaged students and capacity building for engaged teachers in the schools and surrounding communities; hence, this study contributes to a deeper understanding of the impacts of universal mental health intervention for school-aged children.This work was supported by the Community Care Branch of the Ministry of Health,
Saskatchewan
Sedimentary DNA and pigments show increasing abundance and toxicity of cyanoHABs during the Anthropocene
No full text1. Cyanobacterial harmful algal blooms (cyanoHABs) are assumed to be increasing in abundance and toxicity, but comprehensive analysis of change through time is limited, in part, because some key taxa (e.g., Microcystis) leave ambiguous evi- dence of historical abundance and toxicity. Sedimentary DNA (sedDNA) can allow the reconstruction of the cyanobacteria community as well as the frequency of genes specific to cyanotoxin production, enabling us to determine which taxa are present and their potential for toxin-production. 2. Using a combination of droplet digital polymerase chain reaction (ddPCR) and high-throughput sequencing (HTS), we quantified the abundance of cyanobacte- rial genes of known function and changes in cyanobacteria taxa from sedDNA over the last century in nine lakes along a gradient of lake size, depth and trophic state in Minnesota, U.S.A. Using ddPCR, we quantified genes associated with mi- crocystin toxin-producing potential (mcyE), total cyanobacteria (CYA, 16S rRNA) and the genus Microcystis (MICR, 16S rRNA). Using HTS on a subset of lakes, we investigated how the abundance of this toxin-producing gene covaried with the cyanobacteria community composition. We also compared ddPCR and HTS data to fossil pigments, a well-established palaeolimnological method used to track changes in primary producers over time. 3. Our results showed a significant correlation between MICR and the quantity of mcyE gene and cyanobacterial taxa with known toxin- production potential. The abundance of both genes likewise increased concomitantly through time. 4. Community analyses of HTS data showed significant change in cyanobacte- rial communities commencing c. 1950 when major land-use change in this re- gion led to increased lake productivity, and c. 1990 when Dolichospermum and Microcystis genera increased in abundance, and the subtropical exotic cyanobac- teria Raphidiopsis raciborskii and Sphaerospermopsis aphanizomenoides became abundant. Cyanobacteria pigment data reflected these changes only in deeper lakes, suggesting issues related to benthic production or biomarker preservation in shallower systems.This research was funded by a grant from the Gold Bay Foundation
(https://proje cts.propu blica.org/nonpr ofits/organ izati ons/47400
2921) to A.J.H. and by the Minnesota Environment and Natural
Resources Trust Fund as recommended by the Legislative-Citizen
Commission on Minnesota Resources to A.J.H. P.R.L. was funded
by a Canada Research Chair and Canada Foundation for InnovatiFacultyye
Digital twin framework development for apparel manufacturing industry
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Applied Science in Industrial Systems Engineering, University of Regina. vii, 113 p.Apparel manufacturing, being a labor-intensive industry, is evolving into a more complicated, challenging, and dynamic business as a result of fast-changing fashion trends, increased variety, and increased personalization of product demands. Quick and optimized decision-making is extremely important to overcome these barriers. It is necessary to have a mechanism that can ensure real-time visibility of the production process and provide assistance in decision-making.
Digital Twin (DT) provides real-time visibility. It keeps all production data sources in connection, allowing for fast analysis without affecting physical setup. Although most DT ‘research focused on the machine level and automated industries, this has the potential of applying to apparel manufacturing industries as well. This research contributes in several ways to the current literature. 1. This study identifies the research gap and demonstrates its application to apparel manufacturing industries. 2. It develops a methodology describing step-by-step guidance for applying apparel manufacturing plants. 3. A case study is instantiated to authenticate the methodology. Using the suggested idea and technique, the case study creates a DT of a sewing assembly line. It collects real-time data and carried out simulations dynamically to reduce bottleneck operations. It also communicated production downtime with users instantly to reduce downtime by responding quickly.
Keywords: DT; Apparel Manufacturing; Sewing Assembly Line; Production Efficiency; Production Downtime.Studentye
The effect of mask wearing and emotional deficits on lateralized perception and expression of emotion
No full textA Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science (Honours) in Psychology, University of Regina. 51 p.The posing bias is the phenomenon explaining that individuals perceive and express emotion more in the left side of the face. This is based on the right hemisphere hypothesis, which posits that emotions are typically processed in the right hemisphere of the brain. This study aims to assess this neurological bias in cases where not all facial cues are visible in the case of widespread mask-wearing during the COVID-19 pandemic, especially in relation to emotion expression and perception deficits. Deficits of emotion perception and expression of interest are the result of autism spectrum disorder (ASD), wherein people with ASD have a significantly harder time recognizing and expressing emotion. ASD has also been linked to the subclinical emotional processing deficit called alexithymia, which is the inability to recognize or express others’ or one’s own emotions. The current study investigated these deficits and the influence that masking has on emotion perception and expression. In the present study, we recruited 44 undergraduate students who completed handedness, ASD, and alexithymia questionnaires and participated in two tasks: a forced choice task where they were presented with images posed left or right with and without a mask, and an expression task where they posed with and without a mask after reading two scripts. Findings suggest that alexithymia may be a better predictor of emotion expression and perception deficits than ASD, and that mask wearing may modulate lateral posing, warranting further review.Studentn