I denna uppsats utreds vilka metoder och åtgärder som bidrar till att en stad blir cykelvänlig. Syftet är att undersöka vilka åtgärder som bidrar till att fler väljer att cykla inom staden samt underlättar för de som cyklar. Målsättningen är att komma fram till vilka åtgärder och tillvägagångssätt som en kommun kan använda sig av för att bli mer cykelvänlig och därigenom underlätta för miljövänligt resande.  Först läggs en kunskapsgrund vilken mynnar ut i en hypotes om vilka aspekter och områden som är viktiga för att underlätta för och skapa en stadsstruktur som är gynnsam för cyklister. Därefter genomförs en fall- studie av hur Helsingborgs stad, Lunds kommun och Malmö stad har arbetat med cykelplanering och cykelfrämjande åtgärder. Slutligen skapas utifrån hypotesen en bedömningsmall i resultatavsnittet mot vilken kommunernas arbete bedöms och utvärderas. Resultatet ligger till grund för en vidare analys och diskussion kring om en cykelvänlig stad är uppnåbar samt vad det kan bero på att kommuner fokuserar resurser och arbete på vissa aspekter av cykelplanering medan de inte arbetar med andra.

A large number of proteins interact with biological membranes, either integrated in the membrane (PepTSo2), embedded on a membrane surface (5-lipoxygenase) or encircling a cutout of lipid bilayer (apolipoprotein1 (apoA-I). They function as transporters, receptors or biocatalysts in cellular processes like inflammation or cholesterol transport which are touched upon here. Malfunction of specific membrane proteins are the cause for several diseases or disorders. Knowledge of protein structure supports understanding of its mechanism of function. Here, transmission electron microscopy (TEM) was used for structure determination. To obtain structure information to high resolution for membrane proteins, normally surrounded by lipids, demands specific methods and materials for stabilization. Stabilized in detergent the structure of the bacterial transporter PepTSo2 was shown to form a tetramer even bound to substrate. However, with a protein based stabilizer, Salipro, the structure of PepTSo2 could be determined to high resolution. High density lipoprotein (HDL) in blood plasma, involved in the removal of cholesterol from peripheral tissues, have a central role in cardiovascular function, metabolic syndrome and diabetes. The HDL-particle is composed of two copies of ApoA1 and around hundred lipid molecules. From TEM data, for the first time the clearly discoidal shape could be shown by 3-dimendional reconstructions. These were used for modelling the ApoA1 protein dimer by a "biased fitting" procedure. The results indicate how ApoA1 folds around a lipid bilayer in a disc-shaped structure. Modified HDL called nanodiscs were here used to show the Ca2+ dependent binding of 5-lipoxygenase on the nanodisc bilayer and thereby increased production of the inflammatory mediator leukotrieneA4. Dimerization of 5-lipoxygenase inactivates these functions. / <p>QC 20170323</p>

L’explosion de la nanotechnologie a permis l’intégration d’une multitude de nanoparticules dans des produits de consommation. Les nanoparticules d’argent (nAg) sont les plus utilisées à ces fins, selon les derniers recensements disponibles. La plupart des études toxicologiques, à ce jour, ont fait état de l’implication très évidente de l’ion Ag+ dans la toxicité aigüe des nAg; cependant, quelques études ont mis en évidence des effets toxicologiques dus aux nAg. Il y a un certain consensus à propos d’un risque de contamination des eaux douces via leur rejet par les effluents des réseaux d’aqueducs. Puisque les concentrations en Ag+ sont généralement très faibles dans les eaux douces (de l’ordre du pg L-1), de par la formation de complexes non-labiles avec des thiols (organiques et inorganiques) et des sulfures, la toxicité inhérente aux nAg pourrait ne pas être négligeable- comparativement aux tests en laboratoires. Cette étude s’intéressait donc aux mécanismes de bioaccumulation d’argent par l’algue verte C. reinhardtii suite à l’exposition à des nAg de 5 nm (enrobage d’acide polyacrylique). La bioaccumulation d’argent pour l’exposition à Ag+ servait de point de comparaison; également, les abondances de l’ARNm de l’isocitrate lyase 1 (ICL1) et de l’ARNm de Copper Transporter 2 (CTR2) étaient mesurées comme témoins biologiques de la bioaccumulation de Ag+. Les expériences ont été menées en présence d’un tampon organique (NaHEPES, 2 x 10-2 M; Ca2+, 5x 10-5 M) à pH de 7,00. Pour des expositions à temps fixe de 2 heures, la bioaccumulation d’argent pour nAg était supérieure à ce qui était prédit par sa concentration initiale en Ag+; cependant, il n’y avait pas de différence d’abondance des ARNm de ICL1 et de CTR2 entre nAg et Ag+. D’un autre côté, pour une exposition à temps variables, la bioaccumulation d’argent pour nAg était supérieure à ce qui était prédit par sa concentration initiale en Ag+ et une augmentation de l’abondance de l’ARNm de ICL1 était notée pour nAg. Cependant, il n’y avait aucune différence significative au niveau de l’abondance de l’ARNm de CTR2 entre nAg et une solution équivalente en Ag+. L’ajout d’un fort ligand organique (L-Cystéine; log K= 11,5) à une solution de nAg en diminuait radicalement la bioaccumulation d’argent par rapport à nAg-sans ajout de ligand. Par contre, l’abondance des ARNm de ICL1 et de CTR2 étaient stimulées significativement par rapport à une solution contrôle non-exposée à nAg, ni à Ag+. Les résultats suggéraient fortement que les nAg généraient des ions Ag+ au contact de C. reinhardtii. / The recent developments in nanotechnology have given rise to a new and increasing economical market where nanoparticles are at the forefront. Recent inventories of the nanoparticles-containing products have shown that silver nanoparticle- containing products are the most frequently used consumer nanomaterial. Due to the fear of a large scale contamination-and even pollution- of the aquatic environment from silver nanoparticles (nAg), studies have been conducted to assess their toxicities, which, in many cases, have been found to be mediated by the concomitant presence of Ag+. Notably, few studies have found evidence of toxicity due to the nAg, per se. Since numerous non-labile complexes are formed with Ag+ in freshwaters- especially with thiols and sulfides-, nAg toxicity might be more relevant in comparison to laboratory tests where the Ag+ tends to dominate toxicity studies. Therefore, this study investigated the mechanisms underlying silver bioaccumulation by the green alga, C. reinhardtii upon exposure to solutions of nAg (nominal size of 5 nm; poly-acrylate coating). Silver bioaccumulation upon exposures to the free ion alone served for comparison. In parallel, the abundance of two mRNAs- ICL1 and CTR2- were used to better understand the mechanisms underlying the bioaccumulation of Ag+ (and potentially nAg). The experiments were conducted in pH buffered solutions (NaHEPES, 2 x 10-2 M; Ca2+, 5x 10-5 M) at pH 7.00. For 2-hour exposures, the silver bioaccumulation for solutions of nAg exceeded what was expected from their Ag+ content only; however, no differences were noticed in the abundance of the expression of ICL1 and CTR2. For variable time exposures, the silver bioaccumulation for solutions of nAg exceeded what was expected from their Ag+ content only. Moreover, the expression of ICL1 was significantly higher for nAg than what was expected based upon an exposure to Ag+ only. When exposed to nAg, expression levels of CTR2 could be predicted from levels based solely on the Ag+ concentrations. The addition of a large excess of L-Cysteine, which is a very strong silver ligand (log K =11.5), to a nAg solution largely decreased silver bioaccumulation, however, bioaccumulation remained significant and the expression of both ICL1 and CTR2 were significantly higher than that of the control solutions (without Ag+). The results strongly suggest that nAg generated Ag+ ions when in contact with C. reinhardtii and that the nAg released to freshwaters might exert its toxicity through organism-contact-dependant release of Ag+.

Les anthracyclines tels que la doxorubicin et la daunorubicin sont une famille de médicaments anticancéreux hydrophiles qui doivent être transportés dans les cellules afin d’exercer leur action par intercalation à l’ADN dans le noyau cellulaire. Ceci mène à la perturbation du métabolisme de l’ADN et entraine la mort cellulaire. Les anthracyclines sont utilisés pour le traitement d’une variété de cancers incluant la leucémie, les lymphomes, le cancer du sein, le cancer des poumons et le cancer des ovaires. Étant donné que le transport actif des anthracyclines dans les cellules a partiellement été démontré, le transporteur spécifique impliqué dans ce processus n’est pas encore connu. En utilisant un modèle de cancer des ovaires, la lignée cellulaire TOV2223G, nous avons démontré que des substrats spécifiques au transporteur de cations organiques 1 (OCT1), notamment la ergothionéine, la thiamine et la phenformin, ont partiellement inhibé l’absorption de la daunorubicin en différence de la carnitine qui est un substrat de haute affinité des transporteurs CT2 et OCTN2. Ces résultats suggèrent que les transporteurs organiques spécifiques au transport de la carnitine ne sont pas impliqués dans le transport des anthracyclines. Ainsi, nos résultats ont démontré que l’absorption de la daunorubicin est orchestrée par le transporteur OCT1 dans les cellules TOV2223G (Km ~ 5 μM) et des concentrations micromolaires de choline ont complètement abolies l’absorption de la drogue. De plus, un ARN sh dirigé contre OCT1 a réprimé son expression protéique, ce qui a été confirmé par la technique d’immuno-buvardage en utilisant un anti-OCT1 anticorps. Les cellules déficientes en OCT1 n’ont pas été capables d’absorber la daunorubicin et ont été plus résistantes à l’action de la drogue par rapport aux cellules contrôle. La transfection des cellules HEK293T avec un plasmide construit de façon à faire exprimer OCT1 comme protéine de fusion avec la protéine fluorescente EYFP a montré que celle-ci est localisée dans la membrane plasmique. Les cellules transfectées ont été capables d’absorber cinq fois plus de daunorubicin comparé aux cellules contrôles. Cette étude est, selon nous, la première à démontrer que OCT1 est un transporteur de haute affinité des anthracyclines. Ainsi, nous avons émis l’hypothèse que des défauts de OCT1 peuvent contribuer à l’efficacité de la réponse des cellules cancéreuses à la chimiothérapie avec les anthracyclines. / Anthracyclines such as doxorubicin and daunorubicin are hydrophilic anticancer agents that must be transported into cells. These drugs accumulate in the nucleus where they intercalate with DNA, thereby interfering with DNA replication in turn leading to cell death. Anthracyclines are used for treating a variety of cancers including leukemia, lymphomas, breast, lung, and ovarian. Despite evidence for active uptake of anthracyclines, the specific transporter has not been identified. Using the ovarian cancer cell line TOV2223G, we show that substrates reported for the organic cation transporter OCT1, such as ergothioneine, thiamine and phenformin, partially compete with uptake of daunorubicin, but not of L-carnitine, i.e., a high affinity substrate transported by hCT2 and OCTN2. These findings exclude the involvement of the L-carnitine organic cation family of transporters in anthracycline uptake. Moreover, we show that OCT1 actively mediates high affinity (Km ~ 5 μM) transport of daunorubicin into TOV2223G cells, whereas micromolar amounts of choline completely abolish drug uptake. shRNA-mediated downregulation of OCT1 causes defective uptake of daunorubicin, as well as significant resistance to the drug, as compared to the vector control. Transfection of HEK293T cells with a plasmid expressing OCT1 as a GFP fusion protein revealed that OCT1-EYFP was predominantly localized to the plasma membrane. These transfected cells manifested nearly 5-fold increased uptake of daunorubicin compared to the empty vector control. In summary, we show for the first time that human OCT1 is a high affinity transporter for anthracyclines. As such, we postulate that OCT1 status represents a critical determinant in the response of cancer cells to chemotherapy with anthracyclines

Resistance to chemotherapeutics is a widespread phenomenon in cancer cells that may counteract the successful therapy of many patients. In resistant cells, higher level of ABC transporters, among others, often can be detected. This high level of ABC transporters represents a suspected mechanism of acquired cancer resistance. We studied the molecular mechanism of resistance to taxanes in cancer cells using SK-BR-3 and MCF-7 breast cancer cell lines. We analyzed the effect of paclitaxel on apoptosis induction in the originally sensitive cells of these lines as compared to their counterpart resistant cells, developed by gradual adaptation to paclitaxel. In resistant cells of the SK-BR-3 and MCF-7 lines, we did not detected ongoing induction of apoptosis but we did detect significantly increased expression of ABCB1 transporter after paclitaxel application. By silencing the expression of the transport via employment of small interfering RNA (siRNA), we tested the role of the ABCB1 transporter in cells resistant to paclitaxel. We found that resistant cells with silenced expression of the ABCB1 transporter had a statistically significant increase of sensitivity to paclitaxel as compared to control resistant cells with high expression of this transporter. Along with increased sensitivity, we demonstrated...

Le glutamate est le principal neurotransmetteur excitateur du noyau du tractus solitaire (NTS), une structure sensorielle qui reçoit des informations provenant des viscères. Nous avons utilisé l'immunocytochimie et la microscopie électronique pour étudier les systèmes de recapture du glutamate dans le NTS. Nous montrons que le transporteur exprimé par les astrocytes est de type GLT-1 et que la couverture des synapses glutamatergiques par les processus astrocytaires n'est pas complète ce qui autorise des phénomènes de transmission à distance par diffusion du glutamate. Nous montrons aussi que les dendrites des neurones du NTS expriment le transporteur de type EAAC1. Ce transporteur est essentiellement présent sous forme d'un pool intracellulaire. Son expression membranaire pourrait donc être régulée par l'activité. Enfin, dans une dernière partie, nous montrons qu'une inflammation des viscères induit une augmentation de la couverture gliale des synapses glutamatergiques du NTS. / Glutamate is the main excitatory transmitter in the nucleus tractus solitarii (NTS), a sensory nucleus involved in visceral information processing. Using electron microscope immunocytochemistry, we have investigated neuron to glia relationships and localization of glutamate transporters in the NTS. We show that NTS astrocytes express GLT-1 and that astrocytic wrapping of NTS glutamatergic synapses is incomplete, allowing glutamate to diffuse out of the synaptic cleft. In addition, we demonstrate that NTS neurons express the EAAC1 transporter. EAAC1 is exclusively present in dendrites and mostly located intracellularly. Finally, we show that visceral inflammation increases the glial wrapping of NTS glutamatergic synapses.

Bakgrund: Anläggningslokalisering är för de flesta organisationer ett strategiskt beslut och traditionellt sett har dessa beslut beserats på kostnadsorienterade modeller. Dessa modeller kan beskrivas som matematiska eller faktorvärderande. Historiskt sett har dessa modeller använts för att bestämma ekonomiskt lämpliga placeringar men när andra fördelar som miljö och sociala fördelar kan öka en organisations konkurrensfördelar har intresset för hållbar utveckling ökat. I dagsläget finns dock inga modeller där hänsyn tas till hållbar utveckling för anläggningslokalisering. Det framgår att kunskapen om hållbar utveckling vid logistiklokalisering är bristfällig och att det finns ett behov att introducera hållbara aspekter vid beslutsfattande som rör lokalisering. Syfte: Syftet med studien var att kartlägga vilka hållbara faktorer som är viktigast vid logistiklokalisering samt att rangordna dessa med en modell som utgår ifrån de tre dimensionerna av hållbar utveckling; ekonomi, socialt och miljö. Metod: En litteraturstudie gjordes på vetenskapliga artiklar, böcker och dokument som berör de ämnen som varit aktuella för denna studie. För att komplettera teorin gjordes en fallstudie med intervjuer på organisationer som jobbar med regional utveckling samt med en upphovsman av en lokaliseringsmodell som börjat jobba med hållbarhet. Resultat: I resultatet samlades respondenternas synpunkter om hållbarhet och arbetet med hållbar utveckling inom logistiketableringar. Analys och Diskussion: det framkom att respondenterna hade lite olika synvinklar på hållbarhet men att de ändå kom fram till samma slutsats. Samtliga respondenter tog upp hållbara transporter, kompetenstillgången och tillgången på arbetskraft som viktiga aspekter för hållbara etableringar. För att motivera hållbara logistikverksamhets-lokaliseringar visade sig tillgången till dessa faktorer vara viktiga. När analysen sammanställdes visade det sig att sex faktorer trädde fram i intervjusvaren samt även i teorin. Dessa var hållbar infrastruktur, livscykelperspektiv, omgivningens påverkan, logistikparker, arbetskraft och mångfald. Slutsats: De sex kriterierna som togs fram rangordnades med hjälp av en AHP-beslutsmodell och det visade sig att hållbar infrastruktur är viktigast för hållbar utveckling inom logistiklokaliseringar. Därefter kom livscykelperspektiv, logistikparker, arbetskraft, omgivningens påverkan och till sist mångfald. Lärdomarna efter denna studie är att hållbarhet inom lokalisering fortfarande är bristfällig och att lokalisering bör ske utifrån samarbeten och arbetskraftutveckling i större grad. Genom att föreslå viktiga faktorer finns nu ett ramverk att jobba efter när det kommer till hållbara logistiklokaliseringar. / Background: Facility location is for most organizations a strategic decision and traditionally, these decisions have been based on cost-oriented models. These models can be described as mathematical or evaluative factor. Historically, these models are used to determine the appropriate economic placements but other benefits such as environmental and social benefits can increase an organization's competitive advantage when interest in sustainable development has increased. In the current situation, there are no models that take into account sustainable development in facility location. It is clear that knowledge of sustainable development in logistics business location is flawed and that there is a need to introduce sustainable aspects when making decisions related to localization problems. Purpose: The purpose of this study was to identify the most important sustainable factors in logistics business location and to rank them with a model based on the three dimensions of sustainable development; economic, social and environmental. Method: A literature review was conducted based on scientific articles, books and documents related to the topics that have been considered for this study. To complement the theory a case study was implemented based on interviews with organizations that work with regional development as well as an author of a localization model with sustainable aspects. Results: The respondents view on sustainability and sustainability in logistics were collected in this section. Analysis and Discussion: It was revealed that the respondents had slightly different perspectives on sustainability but they still came to the same conclusion. All respondents talked about sustainable transports, availability of labor workers and also availability of skilled personnel as important aspects of sustainable establishments. To motivate sustainable logistics localizations it came clear that access to these factors is important. When the analysis was compiled, it was found that six factors emerged in the interview responses, as well as in theory. These were sustainable infrastructure, life-cycle perspective, influences on the surroundings, logistics parks, labor and diversity. Conclusion: The six criteria that were developed were ranked using an AHP decision model, and it turned out that sustainable infrastructure is the most important factor for sustainable development in logistics localizations. Then came the life-cycle perspective, logistics parks, labor, influences on the surroundings and ultimately diversity. Lessons learned by this study are that the sustainability in localization is still inadequate and that the localization should be based on partnerships and workforce development to a greater degree. By proposing important factors a framework is developed to work by when it comes to sustainable logistics localizations.

Byggindustrin är reglerad av avtal, överenskommelser och består av flera metoder samt att materialet är beroende av vilken typ av byggnad som ska konstrueras. Varje nytt byggprojekt är en unik produkt på en helt ny plats. Vilket skiljer sig från tillverkningsindustrin, som producerar produkter i fabrik. Från studiens syfte har tre frågeställningar utformats. Metoden som använts för att uppnå syftet och besvara frågeställningar har varit kvalitativ och kvantitativ. Den insamlade data är främst från intervjuer och tidigare studier. Studien har visat att tidigare bygglogistikanalyser saknar eller har otydlig definition av avgörande faktorer och detaljer kring konstruktion av fastigheter samt dess transporter. Analysen av tidigare bygglogistikanalyser har resulterat i antaganden och användbara värden för att utföra en prognos för stadsutvecklingsprojektet Väsjön. Scenarioanalysen visade att projektet generar drygt 240 000 transporter som motsvarar cirka 200 ton koldioxidutsläpp vid bostadsproduktion av 4500 nya bostäder. Analysen visade möjligheten att minska både antalet transporter och utsläpp när olika logistiklösningarna introduceras, såsom en checkpoint- lösning, en terminallösning, en gemensam avfallshantering eller kombination av dem.

O balanço redox em mitocôndrias de mamíferos é realizado pelo transportador de aspartato-glutamato (AGC), o qual é o principal mecanismo para o movimento de equivalentes redutores na forma de NADH. A citrulinemia do tipo II (CTLN2) é uma doença autossômica recessiva de início tardio, causada por mutações no gene SLC25A13 que codifica a citrina. A citrina é uma isoforma do transportador AGC e catalisa o transporte de glutamato citosólico através da troca com o aspartato mitocondrial, o qual será utilizado no ciclo da ureia. A CTLN2 promove uma deficiência no ciclo da ureia e consequente hiperamonemia. A deficiência da citrina promove um aumento da razão NADH/NAD+ citosólica. O aumento dessa razão inibe a glicólise e a gliconeogênese. O desenvolvimento de modelo in vitro da CTLN2 é importante para estudos do mecanismo da doença e de novas terapias. A expressão heteróloga de proteínas entre diferentes reinos tem sido utilizado como uma forma de corrigir algumas doenças mitocondriais. Estudos bioquímicos e moleculares em nosso laboratório demonstraram a presença de um transportador mitocondrial de nicotinamida adenina dinucleotídeo (Ndt1) em Aspergillus fumigatus. Ndt1 realiza o transporte de NAD+ citosólico para a matriz mitocondrial, sendo dessa forma uma proteína importante para manter o balanço redox em A. fumigatus. Assim, o objetivo deste trabalho foi obter uma linhagem de células de mamífero HEK293 com knockdown para o gene SLC25A13, ou seja, um modelo in vitro de CTLN2 e a expressão heteróloga da proteína Ndt1 como uma forma de recuperação do metabolismo. As células com knockdown para o gene SLC25A13 apresentaram um aumento da razão NADH/NAD+ citosólico, redução da glicólise, redução da concentração da ureia e aumento da concentração de amônia. A expressão de Ndt1 foi capaz de reduzir a razão NADH/NAD+ citosólico e recuperou a atividade glicolítica. Entretanto, a expressão de Ndt1 não foi capaz de aumentar a concentração de ureia e reduzir a concentração de amônia causadas pela CTLN2. Dessa forma, nossos resultados sugerem que a expressão da proteína Ndt1 em células de mamíferos recupera o metabolismo mitocondrial e atividade glicolítica das células com CTLN2, mas não melhora o ciclo da ureia e o aumento da concentração de amônia. / Redox balance in mammalian mitochondria is performed by the aspartate-glutamate carrier (AGC), which is the main mechanism for the movement of reducing equivalents in the form of NADH.Type II citrullinemia (CTLN2) is an adult-onset autosomal recessive disease caused by mutations in SLC25A13 gene, and that coding citrin. Citrin is an isoform of AGC and catalyzes the transport of cytosolic glutamate through exchange with mitochondrial aspartate. It will be used in the urea cycle. CTLN2 causes urea cycle deficiency and hyperammonemia. Citrin deficiency cause an increase in the cytosolic NADH/NAD+ ratio. The increase in this ratio inhibits glycolysis and gluconeogenesis. The development an in vitro CTLN2 model is important for new studies about the disease mechanism and new therapies. Heterologous expression of proteins from different organisms has been used to recover some mitochondrial diseases. Biochemical and molecular studies in our laboratory demonstrated the presence of a mitochondrial nicotinamide adenine dinucleotide transporter (Ndt1) in Aspergillus fumigatus. Ndt1 protein performs cytosolic NAD+ transport to the mitochondria matrix, thus being an important protein to keep the redox balance in A. fumigatus. Thus, the aim of this work was to obtain a line of HEK293 mammalian cells with knockdown for the SLC25A13 gene, an in vitro CTLN2 model and the heterologous expression of the Ndt1 protein as a form of metabolism recovery. Cells with citrin knockdown showed an increase of cytosolic NADH/NAD+ ratio, reduction of glycolysis, reduction of urea concentration, and increase of ammonia concentration. Expression of Ndt1 protein was able to reduce cytosolic NADH/NAD+ ratio and recovered the glycolytic activity. However, Ndt1 protein was not able to increase the urea concentration and reduce of ammonia concentration caused by CTLN2. Thus, our results suggest that expression of Ndt1 protein in mammal cells recovers the mitochondrial metabolism and glycolytic activity in CTLN2 cells but does not improve urea cycle and reduce ammonia concentration.

Pouco se sabe sobre o mecanismo de ação da pentamidina, um composto utilizado no tratamento das leishmanioses. Para uma melhor compreensão do mecanismo de ação assim como o mecanismo de resistência à pentamidina, foi isolado um gene que codifica um membro da família de transportadores ABC, chamado PRP1 capaz de conferir resistência à pentamidina em formas promastigotas e amastigotas de Leishmania spp. O tratamento dos transfectantes que superexpressam a PRP1 com pentamidina em presença de concentrações não tóxicas de verapamil, um inibidor de transportadores ABC, foi capaz de reverter a resistência mediada por esse transportador. Foram ainda isolados nesse estudo duas linhagens de L. amazonensis resistentes à pentamidina. A análise molecular dos parasitos indicou que esses mutantes não apresentaram nenhuma amplificação de DNA, inclusive do gene PRP1 que também não se mostrou superexpresso em ambas as linhagens. As duas linhagens resistentes à pentamidina tiveram sua resistência revertida quando tratadas com verapamil, indicando que o mecanismo de resistência nesses mutantes pode estar associado a um transportador ABC. Os resultados obtidos nesse estudo fornecem dados para uma melhor compreensão do mecanismo de resistência à pentamidina e sugerem um provável potencial da associação pentamidina e verapamil no tratamento da doença. / Little it is known about the mechanism of action of pentamidine, an compound used for leishmaniases chemotherapy. To understand the mechanism of action and resistance of pentamidine, it was isolated a gene that codifies a member of ABC transporter family, named as PRP1 able to confer pentamidine resistance in promastigotes and amastigotes of Leishmania spp. Treatment of transfectants overexpressing PRP1 with pentamidine in presence of non toxic concentration of verapamil, an inhibitor of ABC transporters, was able to reverse the drug resistance mediated by this transporter. Two lines of L. amazonensis resistant to pentamidine were selected. Molecular analysis of parasites indicated that these mutants do not contain amplified DNA, including the PRP1 gene either not associated with overexpression in both lines. The two lines resistant to pentamidine had their resistance reversed when treated with verapamil, indicating that the mechanism of resistance may be associated to an ABC transporter. The results of this work lead to new insights for a better understanding of the mechanism of of resistance suggesting a probably potencial of pentamidine and verapamil association in the chemotherapy.