Synthesis of a biotin-functionalized biguanide for the identification of the tumor growth inhibition mechanism of metformin

La metformine est largement utilisée pour réduire le taux de glycémie dans le cas des patients souffrant de diabète de type 2. Dans des études récentes, les chercheurs ont observé une association inverse entre l'utilisation de la metformine et le cancer dans différents tissus. L'inhibition du complexe I de la chaine respiratoire des mitochondries a été considéré responsable pour l'activité antinéoplasique de la metformine, mais le mécanisme par lequel la metformine conduit à inhiber le complexe I et, par conséquent, la prolifération des cellules cancéreuses, n'a jamais été entièrement démontrée ou comprise. Dans cette thèse, nous nous somme proposé d'identifier le mécanisme d'action de la metformine et de sa cible dans les mitochondries, en fonctionnalisant la biguanide analogue de la metformine avec de la biotine. Des extraits de mitochondries ont mises en contact avec la metformine biotinylée et ont été séparés sur des colonnes d'affinité contenant de la streptavidine immobilisée. Les protéines éluées après les étapes de lavage ont été analysées par LC-MS/MS et leurs séquences analysées en utilisant l'algorithme BLAST (NCBI). Nous avons isolé et identifié par spectrométrie de masse (MS) une protéine de 8 KDa qui lie spécifiquement et directement la metformine. Cette protéine a été identifiée comme étant la sous-unité de la ATP synthase. Nos résultats suggèrent que la metformine inhibe la prolifération des cellules cancéreuses par l'inhibition directe de l'ATP synthase de la chaîne respiratoire mitochondriale. Les travaux présentés dans cette thèse ont été réalisés dans le département de chimie, en collaboration avec le département de biochimie et médecine moléculaire de l'université de Montréal.Metformin is widely used to reduce high blood sugar levels in type 2 diabetes patients. In recent studies, researchers observed an inverse association between metformin use and cancer incidence in different tissues. Inhibition of the mitochondrial respiratory complex I has been proposed to be the cause of the antineoplastic activity of metformin, but the mechanism by which metformin inhibits the complex I and consequently stops proliferation of cancer cells was not fully identified and understood. In this thesis, we present the functionalization of a biguanide. A metformin - biotin conjugate was synthesized and used to identify the mechanism of action of metformin and its target in mitochondria. Mitochondrial extracts were put in contact with the biotinylated biguanide and were passed over affinity columns containing immobilized streptavidin. The proteins eluted after the washing steps were analyzed by LC-MS/MS and their sequences analyzed using the BLAST algorithm (NCBI). We isolated and identified by mass spectrometry (MS) an 8 KDa protein that specifically and directly binds metformin. This protein has been identified as the ATP synthase-subunit e. Our results suggest that metformin inhibits cancer cell proliferation through the direct inhibition of the ATP synthase of the mitochondrial respiratory chain. The research presented in this thesis has been performed in the Department of Chemistry, in collaboration with the Department of Biochemistry and Molecular Medicine, at the University of Montreal

Silence as an Educational Tool to Deconstruct Normative Societal Structures and Create Epistemic Trust

This article advances a teaching strategy to help students reflect on how they engage in class discussion by considering silence and silencing of voices in classroom discussions among peers as epistemic violence where a student’s capacity as a knower is questioned. We provide examples of silence(ing) we experienced as graduate international students from the Global South studying educational policy and leadership studies in the United States, to then share how we have used silence as a pedagogical tool to deconstruct the assumptions of the field and the society that keeps the silence as normative. We introduce third thinging as a teaching practice to create epistemic trust when ways of knowing and being are incommensurate. We explain in this paper how as educators, silence can be a tool to humanize difference rather than to silence marginalized knowers

Domestic dog ownership in Iran is a risk factor for human infection with Leishmania infantum.

One explanation proposed for the widespread failure to control zoonotic visceral leishmaniasis by culling infected domestic dogs is that wild canids or humans play significant roles in transmission. The aim of this study was to determine the importance of domestic dogs as the reservoir hosts of visceral leishmaniasis in northwest Iran. A random sample of 3,872 children and 199 dogs in 38 villages was surveyed by the direct agglutination test. Dog ownership details among these households were collected by questionnaire. Parasites isolated from 16 patients and 12 dogs were characterized as Leishmania infantum MON-1. Average seroprevalence in dogs (21.6%) was much higher than in children (7%). Child seropositivity increased significantly with village dog density in absolute terms (P < 0.001) and in relation to dog/human ratios (P = 0.028). Dog ownership within villages also was a significant risk factor for child seropositivity (P = 0.003)

Sequence variation in mitochondrial cox1 and nad1 genes of ascaridoid nematodes in cats and dogs from Iran

The study was conducted to determine the sequence variation in two mitochondrial genes, namely cytochrome c oxidase 1 (pcox1) and NADH dehydrogenase 1 (pnad1) within and among isolates of Toxocara cati, Toxocara canis and Toxascaris leonina. Genomic DNA was extracted from 32 isolates of T. cati, 9 isolates of T. canis and 19 isolates of T. leonina collected from cats and dogs in different geographical areas of Iran. Mitochondrial genes were amplified by polymerase chain reaction (PCR) and sequenced. Sequence data were aligned using the BioEdit software and compared with published sequences in GenBank. Phylogenetic analysis was performed using Bayesian inference and maximum likelihood methods. Based on pairwise comparison, intra-species genetic diversity within Iranian isolates of T. cati, T. canis and T. leonina amounted to 0-2.3, 0-1.3 and 0-1.0 for pcox1 and 0-2.0, 0-1.7 and 0-2.6 for pnad1, respectively. Inter-species sequence variation among the three ascaridoid nematodes was significantly higher, being 9.5-16.6 for pcox1 and 11.9-26.7 for pnad1. Sequence and phylogenetic analysis of the pcox1 and pnad1 genes indicated that there is significant genetic diversity within and among isolates of T. cati, T. canis and T. leonina from different areas of Iran, and these genes can be used for studying genetic variation of ascaridoid nematodes. © Cambridge University Press 2014

Immunotherapy Using Autoclaved L. major Antigens and M. vaccae with Meglumine Antimoniate, for the Treatment of Experimental Canine Visceral Leishmaniasis

Background: To evaluate immunotherapy against canine visceral leishmaniasis, Leishmania ma­jor antigen and heat-killed Mycobacterium vaccae (SRL172) were used as stimulators of immune de­fense mechanisms and the results were compared with standard chemotherapy meglumine antimoni­ate.Methods: Nineteen mongrel dogs aging 1-3 years old were used in this experiment. Infection was carried out in 15 out of 19 dogs using L. infantum, isolated from a naturally infected poly-symptomatic dog.Results: All the cases showed positive serologic results by direct agglutination test during 30-60 days following inoculation. In the first group, which was under chemotherapy (GlucantimeR), one of the members showed recurrence of the disease despite rapid effect of the therapeutic protocol. Im­munotherapy using SRL172 caused complete cleaning of the parasite in group 2, but the speed was less than Glucantime. Immunotherapy using L. major antigen combined with M. vaccae in group 3 and combine administration of immunotherapy and chemotherapy in group 4 both were with relapsing of one case in each group. Group 5 and 6 were consisted of positive and negative con­trol dogs, respectively.Conclusion: Immunotherapy seems to be an adjuvant in treatment of canine leishmaniasis but it needs more investigation for final confirmation

Identity and Legitimacy: Iran's Nuclear Ambitions From Non-Traditional Perspectives

This thesis examines the role of national identity in Iranian leaders’ dream to pursue nuclear ambitions and show the world that identity plays a very outstanding role in society’s thoughts. The Iranian national identity components, including the Persian nationality, Shia Islam, Islamic Revolutionary ideology, and modernity and technological advancement showed to be of central importance in policy-making and decision-making. Since the Islamic Revolution of 1979, Iran has always had very effective policies in the Middle East and also in the world. Iran is of paramount importance not only in terms of economy and security but also in terms of cultural identity; in other words, the country’s security is not just limited to security and military issues, but the economic, the societal, the environmental, the political, and the cultural domains, which are causes and effects of security, can affect it. In current decades, Iran’s nuclear programme has been very challenging. Accordingly, in order to have a further understanding of policy-making and managing nuclear ambitions in Iran, one needs to concentrate more on the non-traditional approaches towards security

Development of a Transformational Engagement Model to Study University Community Partnerships

Mutuality of benefits and reciprocity are the characteristics of university community engagement partnerships that render them democratic and enable universities to serve a larger purpose in working with communities. A review of literature shows that 1- mutually beneficial and reciprocal partnerships are not always the case in practice, 2- the terms lack conceptual clarity, and 3- the literature provides varied and at times contradictory evidence on how to develop such partnerships. By bringing the university community engagement literature in conversation with the Social Exchange tradition, particularly, Social Commitments Theory and Reciprocity Theory, through a critical interpretive synthesis approach, this study develops a new model to study university community engagement and partnerships. Transformational Engagement Model (TEM) provides a clear definition for mutuality of benefits and reciprocity, suggests that reciprocity can be developed from mutually beneficial partnerships through a transformational process, and provides recommendations on how to facilitate formation of transformational partnerships. By framing reciprocity as an outcome of transformational partnerships, TEM criticizes the current direction in institutionalizing engagement through training individuals to do the counter-normative work. TEM suggests that intentionality from institutions should be directed toward encouraging formation of transformational partnerships. TEM also criticizes portraying mutually beneficial partnerships as selfish, and reciprocal partnerships as selfless and non-utilitarian. Rather, TEM suggests that reciprocal partnerships have to be mutually beneficial and universities can have self-interest in engaging with communities. Finally, TEM provides recommendation on how to form structures that may facilitate formation of transformational partnerships. First, partnerships should be designed in ways that the relationships between individuals could be sustained for long periods. Second, different task types that incorporate different engagement structures are encouraged. Third, tasks need to be interdependent and groups, and not individuals, should be kept accountable for the partnership outcomes. Finally, engagement structures allow analysis of sophisticated engagement structures and investigation of formation of reciprocity among groups and beyond dyadic relationships. I also argue that TEM’s conceptualization of reciprocity is more aligned with the Deweyan conception of learning by doing that the university community engagement advocates.Educational Leadership Studie

Miltefosine-Induced Apoptotic Cell Death on Leishmania major and L. tropica Strains

The aim of this study was to assess the cytotoxic effects of various concentrations of miltefosine on Leishmania major (MRHO/IR/75/ER) and L. tropica (MHOM/IR/02/Mash10) promastigotes and to observe the programmed cell death features. The colorimetric MTT assay was used to find L. major and L. tropica viability and the obtained results were expressed as 50% inhibitory concentration (IC50). Also, 50% effective doses (ED50) for L. major and L. tropica amastigotes were also determined. Annexin-V FLUOS staining was performed to study the cell death properties of miltefosine using FACS analysis. Qualitative analysis of the total genomic DNA fragmentation was performed by agarose gel electrophoresis. Furthermore, to observe changes in cell morphology, promastigotes were examined using light microscopy. In both strains of L. major and L. tropica, miltefosine induced dose-dependent death with features of apoptosis, including cell shrinkage, DNA laddering, and externalization of phosphatidylserine. The IC50 was achieved at 22 µM and 11 µM for L. major and L. tropica after 48 hr of incubation, respectively. ED50 of L. major and L. tropica amastigotes were 5.7 µM and 4.2 µM, respectively. Our results indicate that miltefosine induces apoptosis of the causative agent of cutaneous leishmaniasis in a dose-dependent manner. Interestingly, L. major did not display any apoptotic changes when it was exposed to miltefosine in concentrations sufficient to kill L. tropica

Antinociceptive & anti-inflammatory effects of Berberis vulgaris L. root's hydroalcoholic extract and determination of it’s possible antinociceptive mechanism in male mice

      Berberis vulgaris L. (B. vulgaris) and specially its root have been used for a long time as a plant medicine in many countries including Iran. This plant is native in different parts of the world and is native in north areas of Iran like Khorasan. Recent research on this plant has shown its different therapeutic effects, Alkaloids especially Berberine has the most therapeutic usage among its compounds. This research is about the effects of Berberis vulgaris L. root's hydroalcoholic extract has done in two parts: its antinociceptive and anti-inflammatory effects was determined by Formalin and Xylene test respectively after determination of mortal plant dosage. Their dosage was 20, 40, 80 and 160 mg/kg. The three drugs include Naloxone 2 mg/kg, Dextromethorphan 20 mg/kg and L-NAME 10 mg/kg  interact with more significant dosage of B. vulgaris. The results showed antinociceptive and anti-inflammatory effects of root’s extract of B. vulgaris in acute and chronic phases of Formalin test. The extract efficiency was analyzed in part two through Formalin test by three drugs individually and also by root’s extract. Conclusion: due to reduction of extract’s antinociceptive effect in both acute and chronic phases after Naloxone injection, it may concluded that the extract shows its signs through opioid receptors